Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs updates from Al Viro:

- more ->d_init() stuff (work.dcache)

- pathname resolution cleanups (work.namei)

- a few missing iov_iter primitives - copy_from_iter_full() and
friends. Either copy the full requested amount, advance the iterator
and return true, or fail, return false and do _not_ advance the
iterator. Quite a few open-coded callers converted (and became more
readable and harder to fuck up that way) (work.iov_iter)

- several assorted patches, the big one being logfs removal

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
logfs: remove from tree
vfs: fix put_compat_statfs64() does not handle errors
namei: fold should_follow_link() with the step into not-followed link
namei: pass both WALK_GET and WALK_MORE to should_follow_link()
namei: invert WALK_PUT logics
namei: shift interpretation of LOOKUP_FOLLOW inside should_follow_link()
namei: saner calling conventions for mountpoint_last()
namei.c: get rid of user_path_parent()
switch getfrag callbacks to ..._full() primitives
make skb_add_data,{_nocache}() and skb_copy_to_page_nocache() advance only on success
[iov_iter] new primitives - copy_from_iter_full() and friends
don't open-code file_inode()
ceph: switch to use of ->d_init()
ceph: unify dentry_operations instances
lustre: switch to use of ->d_init()

Documentation/filesystems/00-INDEX

···
 	- info and mount options for the JFS filesystem.
 locks.txt
 	- info on file locking implementations, flock() vs. fcntl(), etc.
-logfs.txt
-	- info on the LogFS flash filesystem.
 mandatory-locking.txt
 	- info on the Linux implementation of Sys V mandatory file locking.
 ncpfs.txt

Documentation/filesystems/logfs.txt

···
-
-The LogFS Flash Filesystem
-==========================
-
-Specification
-=============
-
-Superblocks
------------
-
-Two superblocks exist at the beginning and end of the filesystem.
-Each superblock is 256 Bytes large, with another 3840 Bytes reserved
-for future purposes, making a total of 4096 Bytes.
-
-Superblock locations may differ for MTD and block devices.  On MTD the
-first non-bad block contains a superblock in the first 4096 Bytes and
-the last non-bad block contains a superblock in the last 4096 Bytes.
-On block devices, the first 4096 Bytes of the device contain the first
-superblock and the last aligned 4096 Byte-block contains the second
-superblock.
-
-For the most part, the superblocks can be considered read-only.  They
-are written only to correct errors detected within the superblocks,
-move the journal and change the filesystem parameters through tunefs.
-As a result, the superblock does not contain any fields that require
-constant updates, like the amount of free space, etc.
-
-Segments
---------
-
-The space in the device is split up into equal-sized segments.
-Segments are the primary write unit of LogFS.  Within each segments,
-writes happen from front (low addresses) to back (high addresses.  If
-only a partial segment has been written, the segment number, the
-current position within and optionally a write buffer are stored in
-the journal.
-
-Segments are erased as a whole.  Therefore Garbage Collection may be
-required to completely free a segment before doing so.
-
-Journal
---------
-
-The journal contains all global information about the filesystem that
-is subject to frequent change.  At mount time, it has to be scanned
-for the most recent commit entry, which contains a list of pointers to
-all currently valid entries.
-
-Object Store
-------------
-
-All space except for the superblocks and journal is part of the object
-store.  Each segment contains a segment header and a number of
-objects, each consisting of the object header and the payload.
-Objects are either inodes, directory entries (dentries), file data
-blocks or indirect blocks.
-
-Levels
-------
-
-Garbage collection (GC) may fail if all data is written
-indiscriminately.  One requirement of GC is that data is separated
-roughly according to the distance between the tree root and the data.
-Effectively that means all file data is on level 0, indirect blocks
-are on levels 1, 2, 3 4 or 5 for 1x, 2x, 3x, 4x or 5x indirect blocks,
-respectively.  Inode file data is on level 6 for the inodes and 7-11
-for indirect blocks.
-
-Each segment contains objects of a single level only.  As a result,
-each level requires its own separate segment to be open for writing.
-
-Inode File
-----------
-
-All inodes are stored in a special file, the inode file.  Single
-exception is the inode file's inode (master inode) which for obvious
-reasons is stored in the journal instead.  Instead of data blocks, the
-leaf nodes of the inode files are inodes.
-
-Aliases
--------
-
-Writes in LogFS are done by means of a wandering tree.  A naïve
-implementation would require that for each write or a block, all
-parent blocks are written as well, since the block pointers have
-changed.  Such an implementation would not be very efficient.
-
-In LogFS, the block pointer changes are cached in the journal by means
-of alias entries.  Each alias consists of its logical address - inode
-number, block index, level and child number (index into block) - and
-the changed data.  Any 8-byte word can be changes in this manner.
-
-Currently aliases are used for block pointers, file size, file used
-bytes and the height of an inodes indirect tree.
-
-Segment Aliases
----------------
-
-Related to regular aliases, these are used to handle bad blocks.
-Initially, bad blocks are handled by moving the affected segment
-content to a spare segment and noting this move in the journal with a
-segment alias, a simple (to, from) tupel.  GC will later empty this
-segment and the alias can be removed again.  This is used on MTD only.
-
-Vim
----
-
-By cleverly predicting the life time of data, it is possible to
-separate long-living data from short-living data and thereby reduce
-the GC overhead later.  Each type of distinc life expectency (vim) can
-have a separate segment open for writing.  Each (level, vim) tupel can
-be open just once.  If an open segment with unknown vim is encountered
-at mount time, it is closed and ignored henceforth.
-
-Indirect Tree
--------------
-
-Inodes in LogFS are similar to FFS-style filesystems with direct and
-indirect block pointers.  One difference is that LogFS uses a single
-indirect pointer that can be either a 1x, 2x, etc. indirect pointer.
-A height field in the inode defines the height of the indirect tree
-and thereby the indirection of the pointer.
-
-Another difference is the addressing of indirect blocks.  In LogFS,
-the first 16 pointers in the first indirect block are left empty,
-corresponding to the 16 direct pointers in the inode.  In ext2 (maybe
-others as well) the first pointer in the first indirect block
-corresponds to logical block 12, skipping the 12 direct pointers.
-So where ext2 is using arithmetic to better utilize space, LogFS keeps
-arithmetic simple and uses compression to save space.
-
-Compression
------------
-
-Both file data and metadata can be compressed.  Compression for file
-data can be enabled with chattr +c and disabled with chattr -c.  Doing
-so has no effect on existing data, but new data will be stored
-accordingly.  New inodes will inherit the compression flag of the
-parent directory.
-
-Metadata is always compressed.  However, the space accounting ignores
-this and charges for the uncompressed size.  Failing to do so could
-result in GC failures when, after moving some data, indirect blocks
-compress worse than previously.  Even on a 100% full medium, GC may
-not consume any extra space, so the compression gains are lost space
-to the user.
-
-However, they are not lost space to the filesystem internals.  By
-cheating the user for those bytes, the filesystem gained some slack
-space and GC will run less often and faster.
-
-Garbage Collection and Wear Leveling
-------------------------------------
-
-Garbage collection is invoked whenever the number of free segments
-falls below a threshold.  The best (known) candidate is picked based
-on the least amount of valid data contained in the segment.  All
-remaining valid data is copied elsewhere, thereby invalidating it.
-
-The GC code also checks for aliases and writes then back if their
-number gets too large.
-
-Wear leveling is done by occasionally picking a suboptimal segment for
-garbage collection.  If a stale segments erase count is significantly
-lower than the active segments' erase counts, it will be picked.  Wear
-leveling is rate limited, so it will never monopolize the device for
-more than one segment worth at a time.
-
-Values for "occasionally", "significantly lower" are compile time
-constants.
-
-Hashed directories
-------------------
-
-To satisfy efficient lookup(), directory entries are hashed and
-located based on the hash.  In order to both support large directories
-and not be overly inefficient for small directories, several hash
-tables of increasing size are used.  For each table, the hash value
-modulo the table size gives the table index.
-
-Tables sizes are chosen to limit the number of indirect blocks with a
-fully populated table to 0, 1, 2 or 3 respectively.  So the first
-table contains 16 entries, the second 512-16, etc.
-
-The last table is special in several ways.  First its size depends on
-the effective 32bit limit on telldir/seekdir cookies.  Since logfs
-uses the upper half of the address space for indirect blocks, the size
-is limited to 2^31.  Secondly the table contains hash buckets with 16
-entries each.
-
-Using single-entry buckets would result in birthday "attacks".  At
-just 2^16 used entries, hash collisions would be likely (P >= 0.5).
-My math skills are insufficient to do the combinatorics for the 17x
-collisions necessary to overflow a bucket, but testing showed that in
-10,000 runs the lowest directory fill before a bucket overflow was
-188,057,130 entries with an average of 315,149,915 entries.  So for
-directory sizes of up to a million, bucket overflows should be
-virtually impossible under normal circumstances.
-
-With carefully chosen filenames, it is obviously possible to cause an
-overflow with just 21 entries (4 higher tables + 16 entries + 1).  So
-there may be a security concern if a malicious user has write access
-to a directory.
-
-Open For Discussion
-===================
-
-Device Address Space
---------------------
-
-A device address space is used for caching.  Both block devices and
-MTD provide functions to either read a single page or write a segment.
-Partial segments may be written for data integrity, but where possible
-complete segments are written for performance on simple block device
-flash media.
-
-Meta Inodes
------------
-
-Inodes are stored in the inode file, which is just a regular file for
-most purposes.  At umount time, however, the inode file needs to
-remain open until all dirty inodes are written.  So
-generic_shutdown_super() may not close this inode, but shouldn't
-complain about remaining inodes due to the inode file either.  Same
-goes for mapping inode of the device address space.
-
-Currently logfs uses a hack that essentially copies part of fs/inode.c
-code over.  A general solution would be preferred.
-
-Indirect block mapping
-----------------------
-
-With compression, the block device (or mapping inode) cannot be used
-to cache indirect blocks.  Some other place is required.  Currently
-logfs uses the top half of each inode's address space.  The low 8TB
-(on 32bit) are filled with file data, the high 8TB are used for
-indirect blocks.
-
-One problem is that 16TB files created on 64bit systems actually have
-data in the top 8TB.  But files >16TB would cause problems anyway, so
-only the limit has changed.

MAINTAINERS

···
 F:	Documentation/ldm.txt
 F:	block/partitions/ldm.*
 
-LogFS
-M:	Joern Engel <[e-mail]>
-M:	Prasad Joshi <[e-mail]>
-L:	[e-mail]
-W:	logfs.org
-S:	Maintained
-F:	fs/logfs/
-
 LSILOGIC MPT FUSION DRIVERS (FC/SAS/SPI)
 M:	Sathya Prakash <[e-mail]>
 M:	Chaitra P B <[e-mail]>

drivers/bluetooth/hci_vhci.c

···
 	if (!skb)
 		return -ENOMEM;
 
-	if (copy_from_iter(skb_put(skb, len), len, from) != len) {
+	if (!copy_from_iter_full(skb_put(skb, len), len, from)) {
 		kfree_skb(skb);
 		return -EFAULT;
 	}

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

···
 static ssize_t amdgpu_debugfs_regs_read(struct file *f, char __user *buf,
 					size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	ssize_t result = 0;
 	int r;
 	bool pm_pg_lock, use_bank;
···
 static ssize_t amdgpu_debugfs_regs_write(struct file *f, const char __user *buf,
 					 size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	ssize_t result = 0;
 	int r;
 	bool pm_pg_lock, use_bank;
···
 static ssize_t amdgpu_debugfs_regs_pcie_read(struct file *f, char __user *buf,
 					size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	ssize_t result = 0;
 	int r;
 
···
 static ssize_t amdgpu_debugfs_regs_pcie_write(struct file *f, const char __user *buf,
 					 size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	ssize_t result = 0;
 	int r;
 
···
 static ssize_t amdgpu_debugfs_regs_didt_read(struct file *f, char __user *buf,
 					size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	ssize_t result = 0;
 	int r;
 
···
 static ssize_t amdgpu_debugfs_regs_didt_write(struct file *f, const char __user *buf,
 					 size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	ssize_t result = 0;
 	int r;
 
···
 static ssize_t amdgpu_debugfs_regs_smc_read(struct file *f, char __user *buf,
 					size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	ssize_t result = 0;
 	int r;
 
···
 static ssize_t amdgpu_debugfs_regs_smc_write(struct file *f, const char __user *buf,
 					 size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	ssize_t result = 0;
 	int r;
 
···
 static ssize_t amdgpu_debugfs_gca_config_read(struct file *f, char __user *buf,
 					size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	ssize_t result = 0;
 	int r;
 	uint32_t *config, no_regs = 0;
···
 static ssize_t amdgpu_debugfs_sensor_read(struct file *f, char __user *buf,
 					size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	int idx, r;
 	int32_t value;
 

drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c

···
 static ssize_t amdgpu_debugfs_ring_read(struct file *f, char __user *buf,
 					size_t size, loff_t *pos)
 {
-	struct amdgpu_ring *ring = (struct amdgpu_ring*)f->f_inode->i_private;
+	struct amdgpu_ring *ring = file_inode(f)->i_private;
 	int r, i;
 	uint32_t value, result, early[3];
 

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

···
 static ssize_t amdgpu_ttm_vram_read(struct file *f, char __user *buf,
 				    size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	ssize_t result = 0;
 	int r;
 
···
 static ssize_t amdgpu_ttm_gtt_read(struct file *f, char __user *buf,
 				   size_t size, loff_t *pos)
 {
-	struct amdgpu_device *adev = f->f_inode->i_private;
+	struct amdgpu_device *adev = file_inode(f)->i_private;
 	ssize_t result = 0;
 	int r;
 

drivers/net/macvtap.c

···
 	int depth;
 	bool zerocopy = false;
 	size_t linear;
-	ssize_t n;
 
 	if (q->flags & IFF_VNET_HDR) {
 		vnet_hdr_len = q->vnet_hdr_sz;
···
 		len -= vnet_hdr_len;
 
 		err = -EFAULT;
-		n = copy_from_iter(&vnet_hdr, sizeof(vnet_hdr), from);
-		if (n != sizeof(vnet_hdr))
+		if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from))
 			goto err;
 		iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));
 		if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&

drivers/net/tun.c

···
 	bool zerocopy = false;
 	int err;
 	u32 rxhash;
-	ssize_t n;
 
 	if (!(tun->dev->flags & IFF_UP))
 		return -EIO;
···
 			return -EINVAL;
 		len -= sizeof(pi);
 
-		n = copy_from_iter(&pi, sizeof(pi), from);
-		if (n != sizeof(pi))
+		if (!copy_from_iter_full(&pi, sizeof(pi), from))
 			return -EFAULT;
 	}
 
···
 			return -EINVAL;
 		len -= tun->vnet_hdr_sz;
 
-		n = copy_from_iter(&gso, sizeof(gso), from);
-		if (n != sizeof(gso))
+		if (!copy_from_iter_full(&gso, sizeof(gso), from))
 			return -EFAULT;
 
 		if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&

drivers/staging/greybus/camera.c

···
 				      size_t len, loff_t *offset)
 {
 	const struct gb_camera_debugfs_entry *op = file->private_data;
-	struct gb_camera *gcam = file->f_inode->i_private;
+	struct gb_camera *gcam = file_inode(file)->i_private;
 	struct gb_camera_debugfs_buffer *buffer;
 	ssize_t ret;
 
···
 				       loff_t *offset)
 {
 	const struct gb_camera_debugfs_entry *op = file->private_data;
-	struct gb_camera *gcam = file->f_inode->i_private;
+	struct gb_camera *gcam = file_inode(file)->i_private;
 	ssize_t ret;
 	char *kbuf;
 

drivers/staging/greybus/es2.c

···
 static ssize_t apb_log_read(struct file *f, char __user *buf,
 				size_t count, loff_t *ppos)
 {
-	struct es2_ap_dev *es2 = f->f_inode->i_private;
+	struct es2_ap_dev *es2 = file_inode(f)->i_private;
 	ssize_t ret;
 	size_t copied;
 	char *tmp_buf;
···
 static ssize_t apb_log_enable_read(struct file *f, char __user *buf,
 				size_t count, loff_t *ppos)
 {
-	struct es2_ap_dev *es2 = f->f_inode->i_private;
+	struct es2_ap_dev *es2 = file_inode(f)->i_private;
 	int enable = !IS_ERR_OR_NULL(es2->apb_log_task);
 	char tmp_buf[3];
 
···
 {
 	int enable;
 	ssize_t retval;
-	struct es2_ap_dev *es2 = f->f_inode->i_private;
+	struct es2_ap_dev *es2 = file_inode(f)->i_private;
 
 	retval = kstrtoint_from_user(buf, count, 10, &enable);
 	if (retval)

drivers/staging/greybus/svc.c

···
 static ssize_t pwr_debugfs_voltage_read(struct file *file, char __user *buf,
 					size_t len, loff_t *offset)
 {
-	struct svc_debugfs_pwrmon_rail *pwrmon_rails = file->f_inode->i_private;
+	struct svc_debugfs_pwrmon_rail *pwrmon_rails = file_inode(file)->i_private;
 	struct gb_svc *svc = pwrmon_rails->svc;
 	int ret, desc;
 	u32 value;
···
 static ssize_t pwr_debugfs_current_read(struct file *file, char __user *buf,
 					size_t len, loff_t *offset)
 {
-	struct svc_debugfs_pwrmon_rail *pwrmon_rails = file->f_inode->i_private;
+	struct svc_debugfs_pwrmon_rail *pwrmon_rails = file_inode(file)->i_private;
 	struct gb_svc *svc = pwrmon_rails->svc;
 	int ret, desc;
 	u32 value;
···
 static ssize_t pwr_debugfs_power_read(struct file *file, char __user *buf,
 				      size_t len, loff_t *offset)
 {
-	struct svc_debugfs_pwrmon_rail *pwrmon_rails = file->f_inode->i_private;
+	struct svc_debugfs_pwrmon_rail *pwrmon_rails = file_inode(file)->i_private;
 	struct gb_svc *svc = pwrmon_rails->svc;
 	int ret, desc;
 	u32 value;

drivers/staging/greybus/timesync.c

···
 static ssize_t gb_timesync_ping_read(struct file *file, char __user *ubuf,
 				     size_t len, loff_t *offset, bool ktime)
 {
-	struct gb_timesync_svc *timesync_svc = file->f_inode->i_private;
+	struct gb_timesync_svc *timesync_svc = file_inode(file)->i_private;
 	char *buf;
 	ssize_t ret = 0;
 

drivers/staging/lustre/lustre/llite/dcache.c

···
 
 	LASSERT(de);
 	lld = ll_d2d(de);
-	if (!lld) /* NFS copies the de->d_op methods (bug 4655) */
-		return;
-
 	if (lld->lld_it) {
 		ll_intent_release(lld->lld_it);
 		kfree(lld->lld_it);
···
 	return 0;
 }
 
-int ll_d_init(struct dentry *de)
+static int ll_d_init(struct dentry *de)
 {
-	CDEBUG(D_DENTRY, "ldd on dentry %pd (%p) parent %p inode %p refc %d\n",
-	       de, de, de->d_parent, d_inode(de), d_count(de));
-
-	if (!de->d_fsdata) {
-		struct ll_dentry_data *lld;
-
-		lld = kzalloc(sizeof(*lld), GFP_NOFS);
-		if (likely(lld)) {
-			spin_lock(&de->d_lock);
-			if (likely(!de->d_fsdata)) {
-				de->d_fsdata = lld;
-				__d_lustre_invalidate(de);
-			} else {
-				kfree(lld);
-			}
-			spin_unlock(&de->d_lock);
-		} else {
-			return -ENOMEM;
-		}
-	}
-	LASSERT(de->d_op == &ll_d_ops);
-
+	struct ll_dentry_data *lld = kzalloc(sizeof(*lld), GFP_KERNEL);
+	if (unlikely(!lld))
+		return -ENOMEM;
+	lld->lld_invalid = 1;
+	de->d_fsdata = lld;
 	return 0;
 }
 
···
 }
 
 const struct dentry_operations ll_d_ops = {
+	.d_init = ll_d_init,
 	.d_revalidate = ll_revalidate_nd,
 	.d_release = ll_release,
 	.d_delete  = ll_ddelete,

drivers/staging/lustre/lustre/llite/llite_internal.h

···
 
 /* llite/dcache.c */
 
-int ll_d_init(struct dentry *de);
 extern const struct dentry_operations ll_d_ops;
 void ll_intent_drop_lock(struct lookup_intent *);
 void ll_intent_release(struct lookup_intent *);
···
 	 * 'lld_sa_generation == lli->lli_sa_generation'.
 	 */
 	ldd = ll_d2d(dentry);
-	if (ldd && ldd->lld_sa_generation == lli->lli_sa_generation)
+	if (ldd->lld_sa_generation == lli->lli_sa_generation)
 		return false;
 
 	return true;
···
 
 static inline int d_lustre_invalid(const struct dentry *dentry)
 {
-	struct ll_dentry_data *lld = ll_d2d(dentry);
-
-	return !lld || lld->lld_invalid;
-}
-
-static inline void __d_lustre_invalidate(struct dentry *dentry)
-{
-	struct ll_dentry_data *lld = ll_d2d(dentry);
-
-	if (lld)
-		lld->lld_invalid = 1;
+	return ll_d2d(dentry)->lld_invalid;
 }
 
 /*
···
 
 	spin_lock_nested(&dentry->d_lock,
 			 nested ? DENTRY_D_LOCK_NESTED : DENTRY_D_LOCK_NORMAL);
-	__d_lustre_invalidate(dentry);
+	ll_d2d(dentry)->lld_invalid = 1;
 	/*
 	 * We should be careful about dentries created by d_obtain_alias().
 	 * These dentries are not put in the dentry tree, instead they are

drivers/staging/lustre/lustre/llite/llite_nfs.c

···
 	/* N.B. d_obtain_alias() drops inode ref on error */
 	result = d_obtain_alias(inode);
 	if (!IS_ERR(result)) {
-		int rc;
-
-		rc = ll_d_init(result);
-		if (rc < 0) {
-			dput(result);
-			result = ERR_PTR(rc);
-		} else {
-			struct ll_dentry_data *ldd = ll_d2d(result);
-
-			/*
-			 * Need to signal to the ll_intent_file_open that
-			 * we came from NFS and so opencache needs to be
-			 * enabled for this one
-			 */
-			ldd->lld_nfs_dentry = 1;
-		}
+		/*
+		 * Need to signal to the ll_intent_file_open that
+		 * we came from NFS and so opencache needs to be
+		 * enabled for this one
+		 */
+		ll_d2d(result)->lld_nfs_dentry = 1;
 	}
 
 	return result;

drivers/staging/lustre/lustre/llite/namei.c

···
  */
 struct dentry *ll_splice_alias(struct inode *inode, struct dentry *de)
 {
-	struct dentry *new;
-	int rc;
-
 	if (inode) {
-		new = ll_find_alias(inode, de);
+		struct dentry *new = ll_find_alias(inode, de);
 		if (new) {
-			rc = ll_d_init(new);
-			if (rc < 0) {
-				dput(new);
-				return ERR_PTR(rc);
-			}
 			d_move(new, de);
 			iput(inode);
 			CDEBUG(D_DENTRY,
···
 			return new;
 		}
 	}
-	rc = ll_d_init(de);
-	if (rc < 0)
-		return ERR_PTR(rc);
 	d_add(de, inode);
 	CDEBUG(D_DENTRY, "Add dentry %p inode %p refc %d flags %#x\n",
 	       de, d_inode(de), d_count(de), de->d_flags);

drivers/staging/lustre/lustre/llite/statahead.c

···
 	 * dentry_may_statahead().
 	 */
 	ldd = ll_d2d(*dentryp);
-	/* ldd can be NULL if llite lookup failed. */
-	if (ldd)
-		ldd->lld_sa_generation = lli->lli_sa_generation;
+	ldd->lld_sa_generation = lli->lli_sa_generation;
 	sa_put(sai, entry);
 	return rc;
 }

drivers/target/target_core_configfs.c

···
 		pr_err("db_root: cannot open: %s\n", db_root_stage);
 		return -EINVAL;
 	}
-	if (!S_ISDIR(fp->f_inode->i_mode)) {
+	if (!S_ISDIR(file_inode(fp)->i_mode)) {
 		filp_close(fp, 0);
 		mutex_unlock(&g_tf_lock);
 		pr_err("db_root: not a directory: %s\n", db_root_stage);

drivers/usb/gadget/function/f_fs.c

···
 			goto error_mutex;
 		}
 		if (!io_data->read &&
-		    copy_from_iter(data, data_len, &io_data->data) != data_len) {
+		    !copy_from_iter_full(data, data_len, &io_data->data)) {
 			ret = -EFAULT;
 			goto error_mutex;
 		}

drivers/usb/gadget/legacy/inode.c

···
 		return -ENOMEM;
 	}
 
-	if (unlikely(copy_from_iter(buf, len, from) != len)) {
+	if (unlikely(!copy_from_iter_full(buf, len, from))) {
 		value = -EFAULT;
 		goto out;
 	}

drivers/vhost/scsi.c

···
 		 */
 		iov_iter_init(&out_iter, WRITE, vq->iov, out, out_size);
 
-		ret = copy_from_iter(req, req_size, &out_iter);
-		if (unlikely(ret != req_size)) {
+		if (unlikely(!copy_from_iter_full(req, req_size, &out_iter))) {
 			vq_err(vq, "Faulted on copy_from_iter\n");
 			vhost_scsi_send_bad_target(vs, vq, head, out);
 			continue;

drivers/vhost/vhost.c

···
 			       i, count);
 			return -EINVAL;
 		}
-		if (unlikely(copy_from_iter(&desc, sizeof(desc), &from) !=
-			     sizeof(desc))) {
+		if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
 			vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
 			       i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
 			return -EINVAL;

fs/Kconfig

···
 source "fs/jffs2/Kconfig"
 # UBIFS File system configuration
 source "fs/ubifs/Kconfig"
-source "fs/logfs/Kconfig"
 source "fs/cramfs/Kconfig"
 source "fs/squashfs/Kconfig"
 source "fs/freevxfs/Kconfig"

fs/Makefile

···
 obj-$(CONFIG_UFS_FS)		+= ufs/
 obj-$(CONFIG_EFS_FS)		+= efs/
 obj-$(CONFIG_JFFS2_FS)		+= jffs2/
-obj-$(CONFIG_LOGFS)		+= logfs/
 obj-$(CONFIG_UBIFS_FS)		+= ubifs/
 obj-$(CONFIG_AFFS_FS)		+= affs/
 obj-$(CONFIG_ROMFS_FS)		+= romfs/

fs/aio.c

···
 	struct address_space *i_mapping;
 
 	if (aio_ring_file) {
-		truncate_setsize(aio_ring_file->f_inode, 0);
+		truncate_setsize(file_inode(aio_ring_file), 0);
 
 		/* Prevent further access to the kioctx from migratepages */
-		i_mapping = aio_ring_file->f_inode->i_mapping;
+		i_mapping = aio_ring_file->f_mapping;
 		spin_lock(&i_mapping->private_lock);
 		i_mapping->private_data = NULL;
 		ctx->aio_ring_file = NULL;
···
 
 	for (i = 0; i < nr_pages; i++) {
 		struct page *page;
-		page = find_or_create_page(file->f_inode->i_mapping,
+		page = find_or_create_page(file->f_mapping,
 					   i, GFP_HIGHUSER | __GFP_ZERO);
 		if (!page)
 			break;

fs/autofs4/inode.c

···
 		seq_printf(m, ",indirect");
 #ifdef CONFIG_CHECKPOINT_RESTORE
 	if (sbi->pipe)
-		seq_printf(m, ",pipe_ino=%ld", sbi->pipe->f_inode->i_ino);
+		seq_printf(m, ",pipe_ino=%ld", file_inode(sbi->pipe)->i_ino);
 	else
 		seq_printf(m, ",pipe_ino=-1");
 #endif

fs/ceph/dir.c

···
 /*
  * Initialize ceph dentry state.
  */
-int ceph_init_dentry(struct dentry *dentry)
+static int ceph_d_init(struct dentry *dentry)
 {
 	struct ceph_dentry_info *di;
-
-	if (dentry->d_fsdata)
-		return 0;
 
 	di = kmem_cache_zalloc(ceph_dentry_cachep, GFP_KERNEL);
 	if (!di)
 		return -ENOMEM;          /* oh well */
 
-	spin_lock(&dentry->d_lock);
-	if (dentry->d_fsdata) {
-		/* lost a race */
-		kmem_cache_free(ceph_dentry_cachep, di);
-		goto out_unlock;
-	}
-
-	if (ceph_snap(d_inode(dentry->d_parent)) == CEPH_NOSNAP)
-		d_set_d_op(dentry, &ceph_dentry_ops);
-	else if (ceph_snap(d_inode(dentry->d_parent)) == CEPH_SNAPDIR)
-		d_set_d_op(dentry, &ceph_snapdir_dentry_ops);
-	else
-		d_set_d_op(dentry, &ceph_snap_dentry_ops);
-
 	di->dentry = dentry;
 	di->lease_session = NULL;
 	di->time = jiffies;
-	/* avoid reordering d_fsdata setup so that the check above is safe */
-	smp_mb();
 	dentry->d_fsdata = di;
 	ceph_dentry_lru_add(dentry);
-out_unlock:
-	spin_unlock(&dentry->d_lock);
 	return 0;
 }
 
···
 	if (dentry->d_name.len > NAME_MAX)
 		return ERR_PTR(-ENAMETOOLONG);
 
-	err = ceph_init_dentry(dentry);
-	if (err < 0)
-		return ERR_PTR(err);
-
 	/* can we conclude ENOENT locally? */
 	if (d_really_is_negative(dentry)) {
 		struct ceph_inode_info *ci = ceph_inode(dir);
···
 	kmem_cache_free(ceph_dentry_cachep, di);
 }
 
-static int ceph_snapdir_d_revalidate(struct dentry *dentry,
-					  unsigned int flags)
-{
-	/*
-	 * Eventually, we'll want to revalidate snapped metadata
-	 * too... probably...
-	 */
-	return 1;
-}
-
 /*
  * When the VFS prunes a dentry from the cache, we need to clear the
  * complete flag on the parent directory.
···
 
 	/* if we are not hashed, we don't affect dir's completeness */
 	if (d_unhashed(dentry))
+		return;
+
+	if (ceph_snap(d_inode(dentry->d_parent)) == CEPH_SNAPDIR)
 		return;
 
 	/*
···
 	.d_revalidate = ceph_d_revalidate,
 	.d_release = ceph_d_release,
 	.d_prune = ceph_d_prune,
-};
-
-const struct dentry_operations ceph_snapdir_dentry_ops = {
-	.d_revalidate = ceph_snapdir_d_revalidate,
-	.d_release = ceph_d_release,
-};
-
-const struct dentry_operations ceph_snap_dentry_ops = {
-	.d_release = ceph_d_release,
-	.d_prune = ceph_d_prune,
+	.d_init = ceph_d_init,
 };

fs/ceph/export.c

···
 {
 	struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
 	struct inode *inode;
-	struct dentry *dentry;
 	struct ceph_vino vino;
 	int err;
 
···
 			return ERR_PTR(-ESTALE);
 	}
 
-	dentry = d_obtain_alias(inode);
-	if (IS_ERR(dentry))
-		return dentry;
-	err = ceph_init_dentry(dentry);
-	if (err < 0) {
-		dput(dentry);
-		return ERR_PTR(err);
-	}
-	dout("__fh_to_dentry %llx %p dentry %p\n", ino, inode, dentry);
-	return dentry;
+	return d_obtain_alias(inode);
 }
 
 /*
···
 	struct ceph_mds_client *mdsc = ceph_sb_to_client(sb)->mdsc;
 	struct ceph_mds_request *req;
 	struct inode *inode;
-	struct dentry *dentry;
 	int mask;
 	int err;
 
···
 	if (!inode)
 		return ERR_PTR(-ENOENT);
 
-	dentry = d_obtain_alias(inode);
-	if (IS_ERR(dentry))
-		return dentry;
-	err = ceph_init_dentry(dentry);
-	if (err < 0) {
-		dput(dentry);
-		return ERR_PTR(err);
-	}
-	dout("__get_parent ino %llx parent %p ino %llx.%llx\n",
-	     child ? ceph_ino(d_inode(child)) : ino,
-	     dentry, ceph_vinop(inode));
-	return dentry;
+	return d_obtain_alias(inode);
 }
 
 static struct dentry *ceph_get_parent(struct dentry *child)

fs/ceph/file.c

···
 	if (dentry->d_name.len > NAME_MAX)
 		return -ENAMETOOLONG;
 
-	err = ceph_init_dentry(dentry);
-	if (err < 0)
-		return err;
-
 	if (flags & O_CREAT) {
 		err = ceph_pre_init_acls(dir, &mode, &acls);
 		if (err < 0)

fs/ceph/inode.c

···
 	long unsigned half_ttl = from_time + (duration * HZ / 2) / 1000;
 	struct inode *dir;
 
-	/* only track leases on regular dentries */
-	if (dentry->d_op != &ceph_dentry_ops)
-		return;
-
 	spin_lock(&dentry->d_lock);
 	dout("update_dentry_lease %p duration %lu ms ttl %lu\n",
 	     dentry, duration, ttl);
 
 	/* make lease_rdcache_gen match directory */
 	dir = d_inode(dentry->d_parent);
+
+	/* only track leases on regular dentries */
+	if (ceph_snap(dir) != CEPH_NOSNAP)
+		goto out_unlock;
+
 	di->lease_shared_gen = ceph_inode(dir)->i_shared_gen;
 
 	if (duration == 0)
···
 					err = -ENOMEM;
 					goto done;
 				}
-				err = ceph_init_dentry(dn);
-				if (err < 0) {
-					dput(dn);
-					dput(parent);
-					goto done;
-				}
+				err = 0;
 			} else if (d_really_is_positive(dn) &&
 				   (ceph_ino(d_inode(dn)) != vino.ino ||
 				    ceph_snap(d_inode(dn)) != vino.snap)) {
···
 			if (dn == NULL) {
 				dout("d_alloc badness\n");
 				err = -ENOMEM;
-				goto out;
-			}
-			ret = ceph_init_dentry(dn);
-			if (ret < 0) {
-				dput(dn);
-				err = ret;
 				goto out;
 			}
 		} else if (d_really_is_positive(dn) &&

fs/ceph/super.c

···
 			root = ERR_PTR(-ENOMEM);
 			goto out;
 		}
-		ceph_init_dentry(root);
 		dout("open_root_inode success, root dentry is %p\n", root);
 	} else {
 		root = ERR_PTR(err);
···
 	fsc->sb = s;
 
 	s->s_op = &ceph_super_ops;
+	s->s_d_op = &ceph_dentry_ops;
 	s->s_export_op = &ceph_export_ops;
 
 	s->s_time_gran = 1000;  /* 1000 ns == 1 us */

fs/ceph/super.h

···
 extern const struct file_operations ceph_snapdir_fops;
 extern const struct inode_operations ceph_dir_iops;
 extern const struct inode_operations ceph_snapdir_iops;
-extern const struct dentry_operations ceph_dentry_ops, ceph_snap_dentry_ops,
-	ceph_snapdir_dentry_ops;
+extern const struct dentry_operations ceph_dentry_ops;
 
 extern loff_t ceph_make_fpos(unsigned high, unsigned off, bool hash_order);
 extern int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry);
···
 extern void ceph_invalidate_dentry_lease(struct dentry *dentry);
 extern unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn);
 extern void ceph_readdir_cache_release(struct ceph_readdir_cache_control *ctl);
-
-/*
- * our d_ops vary depending on whether the inode is live,
- * snapshotted (read-only), or a virtual ".snap" directory.
- */
-int ceph_init_dentry(struct dentry *dentry);
-
 
 /* ioctl.c */
 extern long ceph_ioctl(struct file *file, unsigned int cmd, unsigned long arg);

fs/compat.c

···
 
 static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstatfs *kbuf)
 {
-	if (sizeof ubuf->f_blocks == 4) {
-		if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail |
-		     kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
+	if (sizeof(ubuf->f_bsize) == 4) {
+		if ((kbuf->f_type | kbuf->f_bsize | kbuf->f_namelen |
+		     kbuf->f_frsize | kbuf->f_flags) & 0xffffffff00000000ULL)
 			return -EOVERFLOW;
 		/* f_files and f_ffree may be -1; it's okay
 		 * to stuff that into 32 bits */

fs/fcntl.c

···
 		   arg |= O_NONBLOCK;
 
 	/* Pipe packetized mode is controlled by O_DIRECT flag */
-	if (!S_ISFIFO(filp->f_inode->i_mode) && (arg & O_DIRECT)) {
+	if (!S_ISFIFO(inode->i_mode) && (arg & O_DIRECT)) {
 		if (!filp->f_mapping || !filp->f_mapping->a_ops ||
 			!filp->f_mapping->a_ops->direct_IO)
 				return -EINVAL;

fs/logfs/Kconfig

···
-config LOGFS
-	tristate "LogFS file system"
-	depends on MTD || (!MTD && BLOCK)
-	select ZLIB_INFLATE
-	select ZLIB_DEFLATE
-	select CRC32
-	select BTREE
-	help
-	  Flash filesystem aimed to scale efficiently to large devices.
-	  In comparison to JFFS2 it offers significantly faster mount
-	  times and potentially less RAM usage, although the latter has
-	  not been measured yet.
-
-	  In its current state it is still very experimental and should
-	  not be used for other than testing purposes.
-
-	  If unsure, say N.

fs/logfs/Makefile

···
-obj-$(CONFIG_LOGFS)	+= logfs.o
-
-logfs-y	+= compr.o
-logfs-y	+= dir.o
-logfs-y	+= file.o
-logfs-y	+= gc.o
-logfs-y	+= inode.o
-logfs-y	+= journal.o
-logfs-y	+= readwrite.o
-logfs-y	+= segment.o
-logfs-y	+= super.o
-logfs-$(CONFIG_BLOCK)	+= dev_bdev.o
-logfs-$(CONFIG_MTD)	+= dev_mtd.o

fs/logfs/compr.c

···
-/*
- * fs/logfs/compr.c	- compression routines
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- */
-#include "logfs.h"
-#include <linux/vmalloc.h>
-#include <linux/zlib.h>
-
-#define COMPR_LEVEL 3
-
-static DEFINE_MUTEX(compr_mutex);
-static struct z_stream_s stream;
-
-int logfs_compress(void *in, void *out, size_t inlen, size_t outlen)
-{
-	int err, ret;
-
-	ret = -EIO;
-	mutex_lock(&compr_mutex);
-	err = zlib_deflateInit(&stream, COMPR_LEVEL);
-	if (err != Z_OK)
-		goto error;
-
-	stream.next_in = in;
-	stream.avail_in = inlen;
-	stream.total_in = 0;
-	stream.next_out = out;
-	stream.avail_out = outlen;
-	stream.total_out = 0;
-
-	err = zlib_deflate(&stream, Z_FINISH);
-	if (err != Z_STREAM_END)
-		goto error;
-
-	err = zlib_deflateEnd(&stream);
-	if (err != Z_OK)
-		goto error;
-
-	if (stream.total_out >= stream.total_in)
-		goto error;
-
-	ret = stream.total_out;
-error:
-	mutex_unlock(&compr_mutex);
-	return ret;
-}
-
-int logfs_uncompress(void *in, void *out, size_t inlen, size_t outlen)
-{
-	int err, ret;
-
-	ret = -EIO;
-	mutex_lock(&compr_mutex);
-	err = zlib_inflateInit(&stream);
-	if (err != Z_OK)
-		goto error;
-
-	stream.next_in = in;
-	stream.avail_in = inlen;
-	stream.total_in = 0;
-	stream.next_out = out;
-	stream.avail_out = outlen;
-	stream.total_out = 0;
-
-	err = zlib_inflate(&stream, Z_FINISH);
-	if (err != Z_STREAM_END)
-		goto error;
-
-	err = zlib_inflateEnd(&stream);
-	if (err != Z_OK)
-		goto error;
-
-	ret = 0;
-error:
-	mutex_unlock(&compr_mutex);
-	return ret;
-}
-
-int __init logfs_compr_init(void)
-{
-	size_t size = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
-			zlib_inflate_workspacesize());
-	stream.workspace = vmalloc(size);
-	if (!stream.workspace)
-		return -ENOMEM;
-	return 0;
-}
-
-void logfs_compr_exit(void)
-{
-	vfree(stream.workspace);
-}

fs/logfs/dev_bdev.c

···
-/*
- * fs/logfs/dev_bdev.c	- Device access methods for block devices
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- */
-#include "logfs.h"
-#include <linux/bio.h>
-#include <linux/blkdev.h>
-#include <linux/buffer_head.h>
-#include <linux/gfp.h>
-#include <linux/prefetch.h>
-
-#define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1))
-
-static int sync_request(struct page *page, struct block_device *bdev, int op)
-{
-	struct bio bio;
-	struct bio_vec bio_vec;
-
-	bio_init(&bio, &bio_vec, 1);
-	bio.bi_bdev = bdev;
-	bio_add_page(&bio, page, PAGE_SIZE, 0);
-	bio.bi_iter.bi_sector = page->index * (PAGE_SIZE >> 9);
-	bio_set_op_attrs(&bio, op, 0);
-
-	return submit_bio_wait(&bio);
-}
-
-static int bdev_readpage(void *_sb, struct page *page)
-{
-	struct super_block *sb = _sb;
-	struct block_device *bdev = logfs_super(sb)->s_bdev;
-	int err;
-
-	err = sync_request(page, bdev, READ);
-	if (err) {
-		ClearPageUptodate(page);
-		SetPageError(page);
-	} else {
-		SetPageUptodate(page);
-		ClearPageError(page);
-	}
-	unlock_page(page);
-	return err;
-}
-
-static DECLARE_WAIT_QUEUE_HEAD(wq);
-
-static void writeseg_end_io(struct bio *bio)
-{
-	struct bio_vec *bvec;
-	int i;
-	struct super_block *sb = bio->bi_private;
-	struct logfs_super *super = logfs_super(sb);
-
-	BUG_ON(bio->bi_error); /* FIXME: Retry io or write elsewhere */
-
-	bio_for_each_segment_all(bvec, bio, i) {
-		end_page_writeback(bvec->bv_page);
-		put_page(bvec->bv_page);
-	}
-	bio_put(bio);
-	if (atomic_dec_and_test(&super->s_pending_writes))
-		wake_up(&wq);
-}
-
-static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
-		size_t nr_pages)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct address_space *mapping = super->s_mapping_inode->i_mapping;
-	struct bio *bio = NULL;
-	struct page *page;
-	unsigned int max_pages;
-	int i, ret;
-
-	max_pages = min_t(size_t, nr_pages, BIO_MAX_PAGES);
-
-	for (i = 0; i < nr_pages; i++) {
-		if (!bio) {
-			bio = bio_alloc(GFP_NOFS, max_pages);
-			BUG_ON(!bio);
-
-			bio->bi_bdev = super->s_bdev;
-			bio->bi_iter.bi_sector = ofs >> 9;
-			bio->bi_private = sb;
-			bio->bi_end_io = writeseg_end_io;
-			bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
-		}
-		page = find_lock_page(mapping, index + i);
-		BUG_ON(!page);
-		ret = bio_add_page(bio, page, PAGE_SIZE, 0);
-
-		BUG_ON(PageWriteback(page));
-		set_page_writeback(page);
-		unlock_page(page);
-
-		if (!ret) {
-			/* Block layer cannot split bios :( */
-			ofs += bio->bi_iter.bi_size;
-			atomic_inc(&super->s_pending_writes);
-			submit_bio(bio);
-			bio = NULL;
-		}
-	}
-
-	if (bio) {
-		atomic_inc(&super->s_pending_writes);
-		submit_bio(bio);
-	}
-	return 0;
-}
-
-static void bdev_writeseg(struct super_block *sb, u64 ofs, size_t len)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int head;
-
-	BUG_ON(super->s_flags & LOGFS_SB_FLAG_RO);
-
-	if (len == 0) {
-		/* This can happen when the object fit perfectly into a
-		 * segment, the segment gets written per sync and subsequently
-		 * closed.
-		 */
-		return;
-	}
-	head = ofs & (PAGE_SIZE - 1);
-	if (head) {
-		ofs -= head;
-		len += head;
-	}
-	len = PAGE_ALIGN(len);
-	__bdev_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT);
-}
-
-
-static void erase_end_io(struct bio *bio)
-{ 
-	struct super_block *sb = bio->bi_private; 
-	struct logfs_super *super = logfs_super(sb); 
-
-	BUG_ON(bio->bi_error); /* FIXME: Retry io or write elsewhere */ 
-	bio_put(bio); 
-	if (atomic_dec_and_test(&super->s_pending_writes))
-		wake_up(&wq); 
-} 
-
-static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index,
-		size_t nr_pages)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct bio *bio = NULL;
-	unsigned int max_pages;
-	int i, ret;
-
-	max_pages = min_t(size_t, nr_pages, BIO_MAX_PAGES);
-
-	for (i = 0; i < nr_pages; i++) {
-		if (!bio) {
-			bio = bio_alloc(GFP_NOFS, max_pages);
-			BUG_ON(!bio);
-
-			bio->bi_bdev = super->s_bdev;
-			bio->bi_iter.bi_sector = ofs >> 9;
-			bio->bi_private = sb;
-			bio->bi_end_io = erase_end_io;
-			bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
-		}
-		ret = bio_add_page(bio, super->s_erase_page, PAGE_SIZE, 0);
-		if (!ret) {
-			/* Block layer cannot split bios :( */
-			ofs += bio->bi_iter.bi_size;
-			atomic_inc(&super->s_pending_writes);
-			submit_bio(bio);
-		}
-	}
-	if (bio) {
-		atomic_inc(&super->s_pending_writes);
-		submit_bio(bio);
-	}
-	return 0;
-}
-
-static int bdev_erase(struct super_block *sb, loff_t to, size_t len,
-		int ensure_write)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	BUG_ON(to & (PAGE_SIZE - 1));
-	BUG_ON(len & (PAGE_SIZE - 1));
-
-	if (super->s_flags & LOGFS_SB_FLAG_RO)
-		return -EROFS;
-
-	if (ensure_write) {
-		/*
-		 * Object store doesn't care whether erases happen or not.
-		 * But for the journal they are required.  Otherwise a scan
-		 * can find an old commit entry and assume it is the current
-		 * one, travelling back in time.
-		 */
-		do_erase(sb, to, to >> PAGE_SHIFT, len >> PAGE_SHIFT);
-	}
-
-	return 0;
-}
-
-static void bdev_sync(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	wait_event(wq, atomic_read(&super->s_pending_writes) == 0);
-}
-
-static struct page *bdev_find_first_sb(struct super_block *sb, u64 *ofs)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct address_space *mapping = super->s_mapping_inode->i_mapping;
-	filler_t *filler = bdev_readpage;
-
-	*ofs = 0;
-	return read_cache_page(mapping, 0, filler, sb);
-}
-
-static struct page *bdev_find_last_sb(struct super_block *sb, u64 *ofs)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct address_space *mapping = super->s_mapping_inode->i_mapping;
-	filler_t *filler = bdev_readpage;
-	u64 pos = (super->s_bdev->bd_inode->i_size & ~0xfffULL) - 0x1000;
-	pgoff_t index = pos >> PAGE_SHIFT;
-
-	*ofs = pos;
-	return read_cache_page(mapping, index, filler, sb);
-}
-
-static int bdev_write_sb(struct super_block *sb, struct page *page)
-{
-	struct block_device *bdev = logfs_super(sb)->s_bdev;
-
-	/* Nothing special to do for block devices. */
-	return sync_request(page, bdev, WRITE);
-}
-
-static void bdev_put_device(struct logfs_super *s)
-{
-	blkdev_put(s->s_bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
-}
-
-static int bdev_can_write_buf(struct super_block *sb, u64 ofs)
-{
-	return 0;
-}
-
-static const struct logfs_device_ops bd_devops = {
-	.find_first_sb	= bdev_find_first_sb,
-	.find_last_sb	= bdev_find_last_sb,
-	.write_sb	= bdev_write_sb,
-	.readpage	= bdev_readpage,
-	.writeseg	= bdev_writeseg,
-	.erase		= bdev_erase,
-	.can_write_buf	= bdev_can_write_buf,
-	.sync		= bdev_sync,
-	.put_device	= bdev_put_device,
-};
-
-int logfs_get_sb_bdev(struct logfs_super *p, struct file_system_type *type,
-		const char *devname)
-{
-	struct block_device *bdev;
-
-	bdev = blkdev_get_by_path(devname, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
-				  type);
-	if (IS_ERR(bdev))
-		return PTR_ERR(bdev);
-
-	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
-		int mtdnr = MINOR(bdev->bd_dev);
-		blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
-		return logfs_get_sb_mtd(p, mtdnr);
-	}
-
-	p->s_bdev = bdev;
-	p->s_mtd = NULL;
-	p->s_devops = &bd_devops;
-	return 0;
-}

fs/logfs/dev_mtd.c

···
-/*
- * fs/logfs/dev_mtd.c	- Device access methods for MTD
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- */
-#include "logfs.h"
-#include <linux/completion.h>
-#include <linux/mount.h>
-#include <linux/sched.h>
-#include <linux/slab.h>
-
-#define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1))
-
-static int logfs_mtd_read(struct super_block *sb, loff_t ofs, size_t len,
-			void *buf)
-{
-	struct mtd_info *mtd = logfs_super(sb)->s_mtd;
-	size_t retlen;
-	int ret;
-
-	ret = mtd_read(mtd, ofs, len, &retlen, buf);
-	BUG_ON(ret == -EINVAL);
-	if (ret)
-		return ret;
-
-	/* Not sure if we should loop instead. */
-	if (retlen != len)
-		return -EIO;
-
-	return 0;
-}
-
-static int loffs_mtd_write(struct super_block *sb, loff_t ofs, size_t len,
-			void *buf)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct mtd_info *mtd = super->s_mtd;
-	size_t retlen;
-	loff_t page_start, page_end;
-	int ret;
-
-	if (super->s_flags & LOGFS_SB_FLAG_RO)
-		return -EROFS;
-
-	BUG_ON((ofs >= mtd->size) || (len > mtd->size - ofs));
-	BUG_ON(ofs != (ofs >> super->s_writeshift) << super->s_writeshift);
-	BUG_ON(len > PAGE_SIZE);
-	page_start = ofs & PAGE_MASK;
-	page_end = PAGE_ALIGN(ofs + len) - 1;
-	ret = mtd_write(mtd, ofs, len, &retlen, buf);
-	if (ret || (retlen != len))
-		return -EIO;
-
-	return 0;
-}
-
-/*
- * For as long as I can remember (since about 2001) mtd->erase has been an
- * asynchronous interface lacking the first driver to actually use the
- * asynchronous properties.  So just to prevent the first implementor of such
- * a thing from breaking logfs in 2350, we do the usual pointless dance to
- * declare a completion variable and wait for completion before returning
- * from logfs_mtd_erase().  What an exercise in futility!
- */
-static void logfs_erase_callback(struct erase_info *ei)
-{
-	complete((struct completion *)ei->priv);
-}
-
-static int logfs_mtd_erase_mapping(struct super_block *sb, loff_t ofs,
-				size_t len)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct address_space *mapping = super->s_mapping_inode->i_mapping;
-	struct page *page;
-	pgoff_t index = ofs >> PAGE_SHIFT;
-
-	for (index = ofs >> PAGE_SHIFT; index < (ofs + len) >> PAGE_SHIFT; index++) {
-		page = find_get_page(mapping, index);
-		if (!page)
-			continue;
-		memset(page_address(page), 0xFF, PAGE_SIZE);
-		put_page(page);
-	}
-	return 0;
-}
-
-static int logfs_mtd_erase(struct super_block *sb, loff_t ofs, size_t len,
-		int ensure_write)
-{
-	struct mtd_info *mtd = logfs_super(sb)->s_mtd;
-	struct erase_info ei;
-	DECLARE_COMPLETION_ONSTACK(complete);
-	int ret;
-
-	BUG_ON(len % mtd->erasesize);
-	if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO)
-		return -EROFS;
-
-	memset(&ei, 0, sizeof(ei));
-	ei.mtd = mtd;
-	ei.addr = ofs;
-	ei.len = len;
-	ei.callback = logfs_erase_callback;
-	ei.priv = (long)&complete;
-	ret = mtd_erase(mtd, &ei);
-	if (ret)
-		return -EIO;
-
-	wait_for_completion(&complete);
-	if (ei.state != MTD_ERASE_DONE)
-		return -EIO;
-	return logfs_mtd_erase_mapping(sb, ofs, len);
-}
-
-static void logfs_mtd_sync(struct super_block *sb)
-{
-	struct mtd_info *mtd = logfs_super(sb)->s_mtd;
-
-	mtd_sync(mtd);
-}
-
-static int logfs_mtd_readpage(void *_sb, struct page *page)
-{
-	struct super_block *sb = _sb;
-	int err;
-
-	err = logfs_mtd_read(sb, page->index << PAGE_SHIFT, PAGE_SIZE,
-			page_address(page));
-	if (err == -EUCLEAN || err == -EBADMSG) {
-		/* -EBADMSG happens regularly on power failures */
-		err = 0;
-		/* FIXME: force GC this segment */
-	}
-	if (err) {
-		ClearPageUptodate(page);
-		SetPageError(page);
-	} else {
-		SetPageUptodate(page);
-		ClearPageError(page);
-	}
-	unlock_page(page);
-	return err;
-}
-
-static struct page *logfs_mtd_find_first_sb(struct super_block *sb, u64 *ofs)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct address_space *mapping = super->s_mapping_inode->i_mapping;
-	filler_t *filler = logfs_mtd_readpage;
-	struct mtd_info *mtd = super->s_mtd;
-
-	*ofs = 0;
-	while (mtd_block_isbad(mtd, *ofs)) {
-		*ofs += mtd->erasesize;
-		if (*ofs >= mtd->size)
-			return NULL;
-	}
-	BUG_ON(*ofs & ~PAGE_MASK);
-	return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb);
-}
-
-static struct page *logfs_mtd_find_last_sb(struct super_block *sb, u64 *ofs)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct address_space *mapping = super->s_mapping_inode->i_mapping;
-	filler_t *filler = logfs_mtd_readpage;
-	struct mtd_info *mtd = super->s_mtd;
-
-	*ofs = mtd->size - mtd->erasesize;
-	while (mtd_block_isbad(mtd, *ofs)) {
-		*ofs -= mtd->erasesize;
-		if (*ofs <= 0)
-			return NULL;
-	}
-	*ofs = *ofs + mtd->erasesize - 0x1000;
-	BUG_ON(*ofs & ~PAGE_MASK);
-	return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb);
-}
-
-static int __logfs_mtd_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
-		size_t nr_pages)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct address_space *mapping = super->s_mapping_inode->i_mapping;
-	struct page *page;
-	int i, err;
-
-	for (i = 0; i < nr_pages; i++) {
-		page = find_lock_page(mapping, index + i);
-		BUG_ON(!page);
-
-		err = loffs_mtd_write(sb, page->index << PAGE_SHIFT, PAGE_SIZE,
-					page_address(page));
-		unlock_page(page);
-		put_page(page);
-		if (err)
-			return err;
-	}
-	return 0;
-}
-
-static void logfs_mtd_writeseg(struct super_block *sb, u64 ofs, size_t len)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int head;
-
-	if (super->s_flags & LOGFS_SB_FLAG_RO)
-		return;
-
-	if (len == 0) {
-		/* This can happen when the object fit perfectly into a
-		 * segment, the segment gets written per sync and subsequently
-		 * closed.
-		 */
-		return;
-	}
-	head = ofs & (PAGE_SIZE - 1);
-	if (head) {
-		ofs -= head;
-		len += head;
-	}
-	len = PAGE_ALIGN(len);
-	__logfs_mtd_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT);
-}
-
-static void logfs_mtd_put_device(struct logfs_super *s)
-{
-	put_mtd_device(s->s_mtd);
-}
-
-static int logfs_mtd_can_write_buf(struct super_block *sb, u64 ofs)
-{
-	struct logfs_super *super = logfs_super(sb);
-	void *buf;
-	int err;
-
-	buf = kmalloc(super->s_writesize, GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
-	err = logfs_mtd_read(sb, ofs, super->s_writesize, buf);
-	if (err)
-		goto out;
-	if (memchr_inv(buf, 0xff, super->s_writesize))
-		err = -EIO;
-	kfree(buf);
-out:
-	return err;
-}
-
-static const struct logfs_device_ops mtd_devops = {
-	.find_first_sb	= logfs_mtd_find_first_sb,
-	.find_last_sb	= logfs_mtd_find_last_sb,
-	.readpage	= logfs_mtd_readpage,
-	.writeseg	= logfs_mtd_writeseg,
-	.erase		= logfs_mtd_erase,
-	.can_write_buf	= logfs_mtd_can_write_buf,
-	.sync		= logfs_mtd_sync,
-	.put_device	= logfs_mtd_put_device,
-};
-
-int logfs_get_sb_mtd(struct logfs_super *s, int mtdnr)
-{
-	struct mtd_info *mtd = get_mtd_device(NULL, mtdnr);
-	if (IS_ERR(mtd))
-		return PTR_ERR(mtd);
-
-	s->s_bdev = NULL;
-	s->s_mtd = mtd;
-	s->s_devops = &mtd_devops;
-	return 0;
-}

fs/logfs/dir.c

···
-/*
- * fs/logfs/dir.c	- directory-related code
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- */
-#include "logfs.h"
-#include <linux/slab.h>
-
-/*
- * Atomic dir operations
- *
- * Directory operations are by default not atomic.  Dentries and Inodes are
- * created/removed/altered in separate operations.  Therefore we need to do
- * a small amount of journaling.
- *
- * Create, link, mkdir, mknod and symlink all share the same function to do
- * the work: __logfs_create.  This function works in two atomic steps:
- * 1. allocate inode (remember in journal)
- * 2. allocate dentry (clear journal)
- *
- * As we can only get interrupted between the two, when the inode we just
- * created is simply stored in the anchor.  On next mount, if we were
- * interrupted, we delete the inode.  From a users point of view the
- * operation never happened.
- *
- * Unlink and rmdir also share the same function: unlink.  Again, this
- * function works in two atomic steps
- * 1. remove dentry (remember inode in journal)
- * 2. unlink inode (clear journal)
- *
- * And again, on the next mount, if we were interrupted, we delete the inode.
- * From a users point of view the operation succeeded.
- *
- * Rename is the real pain to deal with, harder than all the other methods
- * combined.  Depending on the circumstances we can run into three cases.
- * A "target rename" where the target dentry already existed, a "local
- * rename" where both parent directories are identical or a "cross-directory
- * rename" in the remaining case.
- *
- * Local rename is atomic, as the old dentry is simply rewritten with a new
- * name.
- *
- * Cross-directory rename works in two steps, similar to __logfs_create and
- * logfs_unlink:
- * 1. Write new dentry (remember old dentry in journal)
- * 2. Remove old dentry (clear journal)
- *
- * Here we remember a dentry instead of an inode.  On next mount, if we were
- * interrupted, we delete the dentry.  From a users point of view, the
- * operation succeeded.
- *
- * Target rename works in three atomic steps:
- * 1. Attach old inode to new dentry (remember old dentry and new inode)
- * 2. Remove old dentry (still remember the new inode)
- * 3. Remove victim inode
- *
- * Here we remember both an inode an a dentry.  If we get interrupted
- * between steps 1 and 2, we delete both the dentry and the inode.  If
- * we get interrupted between steps 2 and 3, we delete just the inode.
- * In either case, the remaining objects are deleted on next mount.  From
- * a users point of view, the operation succeeded.
- */
-
-static int write_dir(struct inode *dir, struct logfs_disk_dentry *dd,
-		loff_t pos)
-{
-	return logfs_inode_write(dir, dd, sizeof(*dd), pos, WF_LOCK, NULL);
-}
-
-static int write_inode(struct inode *inode)
-{
-	return __logfs_write_inode(inode, NULL, WF_LOCK);
-}
-
-static s64 dir_seek_data(struct inode *inode, s64 pos)
-{
-	s64 new_pos = logfs_seek_data(inode, pos);
-
-	return max(pos, new_pos - 1);
-}
-
-static int beyond_eof(struct inode *inode, loff_t bix)
-{
-	loff_t pos = bix << inode->i_sb->s_blocksize_bits;
-	return pos >= i_size_read(inode);
-}
-
-/*
- * Prime value was chosen to be roughly 256 + 26.  r5 hash uses 11,
- * so short names (len <= 9) don't even occupy the complete 32bit name
- * space.  A prime >256 ensures short names quickly spread the 32bit
- * name space.  Add about 26 for the estimated amount of information
- * of each character and pick a prime nearby, preferably a bit-sparse
- * one.
- */
-static u32 logfs_hash_32(const char *s, int len, u32 seed)
-{
-	u32 hash = seed;
-	int i;
-
-	for (i = 0; i < len; i++)
-		hash = hash * 293 + s[i];
-	return hash;
-}
-
-/*
- * We have to satisfy several conflicting requirements here.  Small
- * directories should stay fairly compact and not require too many
- * indirect blocks.  The number of possible locations for a given hash
- * should be small to make lookup() fast.  And we should try hard not
- * to overflow the 32bit name space or nfs and 32bit host systems will
- * be unhappy.
- *
- * So we use the following scheme.  First we reduce the hash to 0..15
- * and try a direct block.  If that is occupied we reduce the hash to
- * 16..255 and try an indirect block.  Same for 2x and 3x indirect
- * blocks.  Lastly we reduce the hash to 0x800_0000 .. 0xffff_ffff,
- * but use buckets containing eight entries instead of a single one.
- *
- * Using 16 entries should allow for a reasonable amount of hash
- * collisions, so the 32bit name space can be packed fairly tight
- * before overflowing.  Oh and currently we don't overflow but return
- * and error.
- *
- * How likely are collisions?  Doing the appropriate math is beyond me
- * and the Bronstein textbook.  But running a test program to brute
- * force collisions for a couple of days showed that on average the
- * first collision occurs after 598M entries, with 290M being the
- * smallest result.  Obviously 21 entries could already cause a
- * collision if all entries are carefully chosen.
- */
-static pgoff_t hash_index(u32 hash, int round)
-{
-	u32 i0_blocks = I0_BLOCKS;
-	u32 i1_blocks = I1_BLOCKS;
-	u32 i2_blocks = I2_BLOCKS;
-	u32 i3_blocks = I3_BLOCKS;
-
-	switch (round) {
-	case 0:
-		return hash % i0_blocks;
-	case 1:
-		return i0_blocks + hash % (i1_blocks - i0_blocks);
-	case 2:
-		return i1_blocks + hash % (i2_blocks - i1_blocks);
-	case 3:
-		return i2_blocks + hash % (i3_blocks - i2_blocks);
-	case 4 ... 19:
-		return i3_blocks + 16 * (hash % (((1<<31) - i3_blocks) / 16))
-			+ round - 4;
-	}
-	BUG();
-}
-
-static struct page *logfs_get_dd_page(struct inode *dir, struct dentry *dentry)
-{
-	const struct qstr *name = &dentry->d_name;
-	struct page *page;
-	struct logfs_disk_dentry *dd;
-	u32 hash = logfs_hash_32(name->name, name->len, 0);
-	pgoff_t index;
-	int round;
-
-	if (name->len > LOGFS_MAX_NAMELEN)
-		return ERR_PTR(-ENAMETOOLONG);
-
-	for (round = 0; round < 20; round++) {
-		index = hash_index(hash, round);
-
-		if (beyond_eof(dir, index))
-			return NULL;
-		if (!logfs_exist_block(dir, index))
-			continue;
-		page = read_cache_page(dir->i_mapping, index,
-				(filler_t *)logfs_readpage, NULL);
-		if (IS_ERR(page))
-			return page;
-		dd = kmap_atomic(page);
-		BUG_ON(dd->namelen == 0);
-
-		if (name->len != be16_to_cpu(dd->namelen) ||
-				memcmp(name->name, dd->name, name->len)) {
-			kunmap_atomic(dd);
-			put_page(page);
-			continue;
-		}
-
-		kunmap_atomic(dd);
-		return page;
-	}
-	return NULL;
-}
-
-static int logfs_remove_inode(struct inode *inode)
-{
-	int ret;
-
-	drop_nlink(inode);
-	ret = write_inode(inode);
-	LOGFS_BUG_ON(ret, inode->i_sb);
-	return ret;
-}
-
-static void abort_transaction(struct inode *inode, struct logfs_transaction *ta)
-{
-	if (logfs_inode(inode)->li_block)
-		logfs_inode(inode)->li_block->ta = NULL;
-	kfree(ta);
-}
-
-static int logfs_unlink(struct inode *dir, struct dentry *dentry)
-{
-	struct logfs_super *super = logfs_super(dir->i_sb);
-	struct inode *inode = d_inode(dentry);
-	struct logfs_transaction *ta;
-	struct page *page;
-	pgoff_t index;
-	int ret;
-
-	ta = kzalloc(sizeof(*ta), GFP_KERNEL);
-	if (!ta)
-		return -ENOMEM;
-
-	ta->state = UNLINK_1;
-	ta->ino = inode->i_ino;
-
-	inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
-
-	page = logfs_get_dd_page(dir, dentry);
-	if (!page) {
-		kfree(ta);
-		return -ENOENT;
-	}
-	if (IS_ERR(page)) {
-		kfree(ta);
-		return PTR_ERR(page);
-	}
-	index = page->index;
-	put_page(page);
-
-	mutex_lock(&super->s_dirop_mutex);
-	logfs_add_transaction(dir, ta);
-
-	ret = logfs_delete(dir, index, NULL);
-	if (!ret)
-		ret = write_inode(dir);
-
-	if (ret) {
-		abort_transaction(dir, ta);
-		printk(KERN_ERR"LOGFS: unable to delete inode\n");
-		goto out;
-	}
-
-	ta->state = UNLINK_2;
-	logfs_add_transaction(inode, ta);
-	ret = logfs_remove_inode(inode);
-out:
-	mutex_unlock(&super->s_dirop_mutex);
-	return ret;
-}
-
-static inline int logfs_empty_dir(struct inode *dir)
-{
-	u64 data;
-
-	data = logfs_seek_data(dir, 0) << dir->i_sb->s_blocksize_bits;
-	return data >= i_size_read(dir);
-}
-
-static int logfs_rmdir(struct inode *dir, struct dentry *dentry)
-{
-	struct inode *inode = d_inode(dentry);
-
-	if (!logfs_empty_dir(inode))
-		return -ENOTEMPTY;
-
-	return logfs_unlink(dir, dentry);
-}
-
-/* FIXME: readdir currently has it's own dir_walk code.  I don't see a good
- * way to combine the two copies */
-static int logfs_readdir(struct file *file, struct dir_context *ctx)
-{
-	struct inode *dir = file_inode(file);
-	loff_t pos;
-	struct page *page;
-	struct logfs_disk_dentry *dd;
-
-	if (ctx->pos < 0)
-		return -EINVAL;
-
-	if (!dir_emit_dots(file, ctx))
-		return 0;
-
-	pos = ctx->pos - 2;
-	BUG_ON(pos < 0);
-	for (;; pos++, ctx->pos++) {
-		bool full;
-		if (beyond_eof(dir, pos))
-			break;
-		if (!logfs_exist_block(dir, pos)) {
-			/* deleted dentry */
-			pos = dir_seek_data(dir, pos);
-			continue;
-		}
-		page = read_cache_page(dir->i_mapping, pos,
-				(filler_t *)logfs_readpage, NULL);
-		if (IS_ERR(page))
-			return PTR_ERR(page);
-		dd = kmap(page);
-		BUG_ON(dd->namelen == 0);
-
-		full = !dir_emit(ctx, (char *)dd->name,
-				be16_to_cpu(dd->namelen),
-				be64_to_cpu(dd->ino), dd->type);
-		kunmap(page);
-		put_page(page);
-		if (full)
-			break;
-	}
-	return 0;
-}
-
-static void logfs_set_name(struct logfs_disk_dentry *dd, const struct qstr *name)
-{
-	dd->namelen = cpu_to_be16(name->len);
-	memcpy(dd->name, name->name, name->len);
-}
-
-static struct dentry *logfs_lookup(struct inode *dir, struct dentry *dentry,
-		unsigned int flags)
-{
-	struct page *page;
-	struct logfs_disk_dentry *dd;
-	pgoff_t index;
-	u64 ino = 0;
-	struct inode *inode;
-
-	page = logfs_get_dd_page(dir, dentry);
-	if (IS_ERR(page))
-		return ERR_CAST(page);
-	if (!page) {
-		d_add(dentry, NULL);
-		return NULL;
-	}
-	index = page->index;
-	dd = kmap_atomic(page);
-	ino = be64_to_cpu(dd->ino);
-	kunmap_atomic(dd);
-	put_page(page);
-
-	inode = logfs_iget(dir->i_sb, ino);
-	if (IS_ERR(inode))
-		printk(KERN_ERR"LogFS: Cannot read inode #%llx for dentry (%lx, %lx)n",
-				ino, dir->i_ino, index);
-	return d_splice_alias(inode, dentry);
-}
-
-static void grow_dir(struct inode *dir, loff_t index)
-{
-	index = (index + 1) << dir->i_sb->s_blocksize_bits;
-	if (i_size_read(dir) < index)
-		i_size_write(dir, index);
-}
-
-static int logfs_write_dir(struct inode *dir, struct dentry *dentry,
-		struct inode *inode)
-{
-	struct page *page;
-	struct logfs_disk_dentry *dd;
-	u32 hash = logfs_hash_32(dentry->d_name.name, dentry->d_name.len, 0);
-	pgoff_t index;
-	int round, err;
-
-	for (round = 0; round < 20; round++) {
-		index = hash_index(hash, round);
-
-		if (logfs_exist_block(dir, index))
-			continue;
-		page = find_or_create_page(dir->i_mapping, index, GFP_KERNEL);
-		if (!page)
-			return -ENOMEM;
-
-		dd = kmap_atomic(page);
-		memset(dd, 0, sizeof(*dd));
-		dd->ino = cpu_to_be64(inode->i_ino);
-		dd->type = logfs_type(inode);
-		logfs_set_name(dd, &dentry->d_name);
-		kunmap_atomic(dd);
-
-		err = logfs_write_buf(dir, page, WF_LOCK);
-		unlock_page(page);
-		put_page(page);
-		if (!err)
-			grow_dir(dir, index);
-		return err;
-	}
-	/* FIXME: Is there a better return value?  In most cases neither
-	 * the filesystem nor the directory are full.  But we have had
-	 * too many collisions for this particular hash and no fallback.
-	 */
-	return -ENOSPC;
-}
-
-static int __logfs_create(struct inode *dir, struct dentry *dentry,
-		struct inode *inode, const char *dest, long destlen)
-{
-	struct logfs_super *super = logfs_super(dir->i_sb);
-	struct logfs_inode *li = logfs_inode(inode);
-	struct logfs_transaction *ta;
-	int ret;
-
-	ta = kzalloc(sizeof(*ta), GFP_KERNEL);
-	if (!ta) {
-		drop_nlink(inode);
-		iput(inode);
-		return -ENOMEM;
-	}
-
-	ta->state = CREATE_1;
-	ta->ino = inode->i_ino;
-	mutex_lock(&super->s_dirop_mutex);
-	logfs_add_transaction(inode, ta);
-
-	if (dest) {
-		/* symlink */
-		ret = logfs_inode_write(inode, dest, destlen, 0, WF_LOCK, NULL);
-		if (!ret)
-			ret = write_inode(inode);
-	} else {
-		/* creat/mkdir/mknod */
-		ret = write_inode(inode);
-	}
-	if (ret) {
-		abort_transaction(inode, ta);
-		li->li_flags |= LOGFS_IF_STILLBORN;
-		/* FIXME: truncate symlink */
-		drop_nlink(inode);
-		iput(inode);
-		goto out;
-	}
-
-	ta->state = CREATE_2;
-	logfs_add_transaction(dir, ta);
-	ret = logfs_write_dir(dir, dentry, inode);
-	/* sync directory */
-	if (!ret)
-		ret = write_inode(dir);
-
-	if (ret) {
-		logfs_del_transaction(dir, ta);
-		ta->state = CREATE_2;
-		logfs_add_transaction(inode, ta);
-		logfs_remove_inode(inode);
-		iput(inode);
-		goto out;
-	}
-	d_instantiate(dentry, inode);
-out:
-	mutex_unlock(&super->s_dirop_mutex);
-	return ret;
-}
-
-static int logfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
-{
-	struct inode *inode;
-
-	/*
-	 * FIXME: why do we have to fill in S_IFDIR, while the mode is
-	 * correct for mknod, creat, etc.?  Smells like the vfs *should*
-	 * do it for us but for some reason fails to do so.
-	 */
-	inode = logfs_new_inode(dir, S_IFDIR | mode);
-	if (IS_ERR(inode))
-		return PTR_ERR(inode);
-
-	inode->i_op = &logfs_dir_iops;
-	inode->i_fop = &logfs_dir_fops;
-
-	return __logfs_create(dir, dentry, inode, NULL, 0);
-}
-
-static int logfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
-		bool excl)
-{
-	struct inode *inode;
-
-	inode = logfs_new_inode(dir, mode);
-	if (IS_ERR(inode))
-		return PTR_ERR(inode);
-
-	inode->i_op = &logfs_reg_iops;
-	inode->i_fop = &logfs_reg_fops;
-	inode->i_mapping->a_ops = &logfs_reg_aops;
-
-	return __logfs_create(dir, dentry, inode, NULL, 0);
-}
-
-static int logfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
-		dev_t rdev)
-{
-	struct inode *inode;
-
-	if (dentry->d_name.len > LOGFS_MAX_NAMELEN)
-		return -ENAMETOOLONG;
-
-	inode = logfs_new_inode(dir, mode);
-	if (IS_ERR(inode))
-		return PTR_ERR(inode);
-
-	init_special_inode(inode, mode, rdev);
-
-	return __logfs_create(dir, dentry, inode, NULL, 0);
-}
-
-static int logfs_symlink(struct inode *dir, struct dentry *dentry,
-		const char *target)
-{
-	struct inode *inode;
-	size_t destlen = strlen(target) + 1;
-
-	if (destlen > dir->i_sb->s_blocksize)
-		return -ENAMETOOLONG;
-
-	inode = logfs_new_inode(dir, S_IFLNK | 0777);
-	if (IS_ERR(inode))
-		return PTR_ERR(inode);
-
-	inode->i_op = &page_symlink_inode_operations;
-	inode_nohighmem(inode);
-	inode->i_mapping->a_ops = &logfs_reg_aops;
-
-	return __logfs_create(dir, dentry, inode, target, destlen);
-}
-
-static int logfs_link(struct dentry *old_dentry, struct inode *dir,
-		struct dentry *dentry)
-{
-	struct inode *inode = d_inode(old_dentry);
-
-	inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
-	ihold(inode);
-	inc_nlink(inode);
-	mark_inode_dirty_sync(inode);
-
-	return __logfs_create(dir, dentry, inode, NULL, 0);
-}
-
-static int logfs_get_dd(struct inode *dir, struct dentry *dentry,
-		struct logfs_disk_dentry *dd, loff_t *pos)
-{
-	struct page *page;
-	void *map;
-
-	page = logfs_get_dd_page(dir, dentry);
-	if (IS_ERR(page))
-		return PTR_ERR(page);
-	*pos = page->index;
-	map = kmap_atomic(page);
-	memcpy(dd, map, sizeof(*dd));
-	kunmap_atomic(map);
-	put_page(page);
-	return 0;
-}
-
-static int logfs_delete_dd(struct inode *dir, loff_t pos)
-{
-	/*
-	 * Getting called with pos somewhere beyond eof is either a goofup
-	 * within this file or means someone maliciously edited the
-	 * (crc-protected) journal.
-	 */
-	BUG_ON(beyond_eof(dir, pos));
-	dir->i_ctime = dir->i_mtime = current_time(dir);
-	log_dir(" Delete dentry (%lx, %llx)\n", dir->i_ino, pos);
-	return logfs_delete(dir, pos, NULL);
-}
-
-/*
- * Cross-directory rename, target does not exist.  Just a little nasty.
- * Create a new dentry in the target dir, then remove the old dentry,
- * all the while taking care to remember our operation in the journal.
- */
-static int logfs_rename_cross(struct inode *old_dir, struct dentry *old_dentry,
-			      struct inode *new_dir, struct dentry *new_dentry)
-{
-	struct logfs_super *super = logfs_super(old_dir->i_sb);
-	struct logfs_disk_dentry dd;
-	struct logfs_transaction *ta;
-	loff_t pos;
-	int err;
-
-	/* 1. locate source dd */
-	err = logfs_get_dd(old_dir, old_dentry, &dd, &pos);
-	if (err)
-		return err;
-
-	ta = kzalloc(sizeof(*ta), GFP_KERNEL);
-	if (!ta)
-		return -ENOMEM;
-
-	ta->state = CROSS_RENAME_1;
-	ta->dir = old_dir->i_ino;
-	ta->pos = pos;
-
-	/* 2. write target dd */
-	mutex_lock(&super->s_dirop_mutex);
-	logfs_add_transaction(new_dir, ta);
-	err = logfs_write_dir(new_dir, new_dentry, d_inode(old_dentry));
-	if (!err)
-		err = write_inode(new_dir);
-
-	if (err) {
-		super->s_rename_dir = 0;
-		super->s_rename_pos = 0;
-		abort_transaction(new_dir, ta);
-		goto out;
-	}
-
-	/* 3. remove source dd */
-	ta->state = CROSS_RENAME_2;
-	logfs_add_transaction(old_dir, ta);
-	err = logfs_delete_dd(old_dir, pos);
-	if (!err)
-		err = write_inode(old_dir);
-	LOGFS_BUG_ON(err, old_dir->i_sb);
-out:
-	mutex_unlock(&super->s_dirop_mutex);
-	return err;
-}
-
-static int logfs_replace_inode(struct inode *dir, struct dentry *dentry,
-		struct logfs_disk_dentry *dd, struct inode *inode)
-{
-	loff_t pos;
-	int err;
-
-	err = logfs_get_dd(dir, dentry, dd, &pos);
-	if (err)
-		return err;
-	dd->ino = cpu_to_be64(inode->i_ino);
-	dd->type = logfs_type(inode);
-
-	err = write_dir(dir, dd, pos);
-	if (err)
-		return err;
-	log_dir("Replace dentry (%lx, %llx) %s -> %llx\n", dir->i_ino, pos,
-			dd->name, be64_to_cpu(dd->ino));
-	return write_inode(dir);
-}
-
-/* Target dentry exists - the worst case.  We need to attach the source
- * inode to the target dentry, then remove the orphaned target inode and
- * source dentry.
- */
-static int logfs_rename_target(struct inode *old_dir, struct dentry *old_dentry,
-			       struct inode *new_dir, struct dentry *new_dentry)
-{
-	struct logfs_super *super = logfs_super(old_dir->i_sb);
-	struct inode *old_inode = d_inode(old_dentry);
-	struct inode *new_inode = d_inode(new_dentry);
-	int isdir = S_ISDIR(old_inode->i_mode);
-	struct logfs_disk_dentry dd;
-	struct logfs_transaction *ta;
-	loff_t pos;
-	int err;
-
-	BUG_ON(isdir != S_ISDIR(new_inode->i_mode));
-	if (isdir) {
-		if (!logfs_empty_dir(new_inode))
-			return -ENOTEMPTY;
-	}
-
-	/* 1. locate source dd */
-	err = logfs_get_dd(old_dir, old_dentry, &dd, &pos);
-	if (err)
-		return err;
-
-	ta = kzalloc(sizeof(*ta), GFP_KERNEL);
-	if (!ta)
-		return -ENOMEM;
-
-	ta->state = TARGET_RENAME_1;
-	ta->dir = old_dir->i_ino;
-	ta->pos = pos;
-	ta->ino = new_inode->i_ino;
-
-	/* 2. attach source inode to target dd */
-	mutex_lock(&super->s_dirop_mutex);
-	logfs_add_transaction(new_dir, ta);
-	err = logfs_replace_inode(new_dir, new_dentry, &dd, old_inode);
-	if (err) {
-		super->s_rename_dir = 0;
-		super->s_rename_pos = 0;
-		super->s_victim_ino = 0;
-		abort_transaction(new_dir, ta);
-		goto out;
-	}
-
-	/* 3. remove source dd */
-	ta->state = TARGET_RENAME_2;
-	logfs_add_transaction(old_dir, ta);
-	err = logfs_delete_dd(old_dir, pos);
-	if (!err)
-		err = write_inode(old_dir);
-	LOGFS_BUG_ON(err, old_dir->i_sb);
-
-	/* 4. remove target inode */
-	ta->state = TARGET_RENAME_3;
-	logfs_add_transaction(new_inode, ta);
-	err = logfs_remove_inode(new_inode);
-
-out:
-	mutex_unlock(&super->s_dirop_mutex);
-	return err;
-}
-
-static int logfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-			struct inode *new_dir, struct dentry *new_dentry,
-			unsigned int flags)
-{
-	if (flags & ~RENAME_NOREPLACE)
-		return -EINVAL;
-
-	if (d_really_is_positive(new_dentry))
-		return logfs_rename_target(old_dir, old_dentry,
-					   new_dir, new_dentry);
-	return logfs_rename_cross(old_dir, old_dentry, new_dir, new_dentry);
-}
-
-/* No locking done here, as this is called before .get_sb() returns. */
-int logfs_replay_journal(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct inode *inode;
-	u64 ino, pos;
-	int err;
-
-	if (super->s_victim_ino) {
-		/* delete victim inode */
-		ino = super->s_victim_ino;
-		printk(KERN_INFO"LogFS: delete unmapped inode #%llx\n", ino);
-		inode = logfs_iget(sb, ino);
-		if (IS_ERR(inode))
-			goto fail;
-
-		LOGFS_BUG_ON(i_size_read(inode) > 0, sb);
-		super->s_victim_ino = 0;
-		err = logfs_remove_inode(inode);
-		iput(inode);
-		if (err) {
-			super->s_victim_ino = ino;
-			goto fail;
-		}
-	}
-	if (super->s_rename_dir) {
-		/* delete old dd from rename */
-		ino = super->s_rename_dir;
-		pos = super->s_rename_pos;
-		printk(KERN_INFO"LogFS: delete unbacked dentry (%llx, %llx)\n",
-				ino, pos);
-		inode = logfs_iget(sb, ino);
-		if (IS_ERR(inode))
-			goto fail;
-
-		super->s_rename_dir = 0;
-		super->s_rename_pos = 0;
-		err = logfs_delete_dd(inode, pos);
-		iput(inode);
-		if (err) {
-			super->s_rename_dir = ino;
-			super->s_rename_pos = pos;
-			goto fail;
-		}
-	}
-	return 0;
-fail:
-	LOGFS_BUG(sb);
-	return -EIO;
-}
-
-const struct inode_operations logfs_dir_iops = {
-	.create		= logfs_create,
-	.link		= logfs_link,
-	.lookup		= logfs_lookup,
-	.mkdir		= logfs_mkdir,
-	.mknod		= logfs_mknod,
-	.rename		= logfs_rename,
-	.rmdir		= logfs_rmdir,
-	.symlink	= logfs_symlink,
-	.unlink		= logfs_unlink,
-};
-const struct file_operations logfs_dir_fops = {
-	.fsync		= logfs_fsync,
-	.unlocked_ioctl	= logfs_ioctl,
-	.iterate_shared	= logfs_readdir,
-	.read		= generic_read_dir,
-	.llseek		= generic_file_llseek,
-};

fs/logfs/file.c

···
-/*
- * fs/logfs/file.c	- prepare_write, commit_write and friends
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- */
-#include "logfs.h"
-#include <linux/sched.h>
-#include <linux/writeback.h>
-
-static int logfs_write_begin(struct file *file, struct address_space *mapping,
-		loff_t pos, unsigned len, unsigned flags,
-		struct page **pagep, void **fsdata)
-{
-	struct inode *inode = mapping->host;
-	struct page *page;
-	pgoff_t index = pos >> PAGE_SHIFT;
-
-	page = grab_cache_page_write_begin(mapping, index, flags);
-	if (!page)
-		return -ENOMEM;
-	*pagep = page;
-
-	if ((len == PAGE_SIZE) || PageUptodate(page))
-		return 0;
-	if ((pos & PAGE_MASK) >= i_size_read(inode)) {
-		unsigned start = pos & (PAGE_SIZE - 1);
-		unsigned end = start + len;
-
-		/* Reading beyond i_size is simple: memset to zero */
-		zero_user_segments(page, 0, start, end, PAGE_SIZE);
-		return 0;
-	}
-	return logfs_readpage_nolock(page);
-}
-
-static int logfs_write_end(struct file *file, struct address_space *mapping,
-		loff_t pos, unsigned len, unsigned copied, struct page *page,
-		void *fsdata)
-{
-	struct inode *inode = mapping->host;
-	pgoff_t index = page->index;
-	unsigned start = pos & (PAGE_SIZE - 1);
-	unsigned end = start + copied;
-	int ret = 0;
-
-	BUG_ON(PAGE_SIZE != inode->i_sb->s_blocksize);
-	BUG_ON(page->index > I3_BLOCKS);
-
-	if (copied < len) {
-		/*
-		 * Short write of a non-initialized paged.  Just tell userspace
-		 * to retry the entire page.
-		 */
-		if (!PageUptodate(page)) {
-			copied = 0;
-			goto out;
-		}
-	}
-	if (copied == 0)
-		goto out; /* FIXME: do we need to update inode? */
-
-	if (i_size_read(inode) < (index << PAGE_SHIFT) + end) {
-		i_size_write(inode, (index << PAGE_SHIFT) + end);
-		mark_inode_dirty_sync(inode);
-	}
-
-	SetPageUptodate(page);
-	if (!PageDirty(page)) {
-		if (!get_page_reserve(inode, page))
-			__set_page_dirty_nobuffers(page);
-		else
-			ret = logfs_write_buf(inode, page, WF_LOCK);
-	}
-out:
-	unlock_page(page);
-	put_page(page);
-	return ret ? ret : copied;
-}
-
-int logfs_readpage(struct file *file, struct page *page)
-{
-	int ret;
-
-	ret = logfs_readpage_nolock(page);
-	unlock_page(page);
-	return ret;
-}
-
-/* Clear the page's dirty flag in the radix tree. */
-/* TODO: mucking with PageWriteback is silly.  Add a generic function to clear
- * the dirty bit from the radix tree for filesystems that don't have to wait
- * for page writeback to finish (i.e. any compressing filesystem).
- */
-static void clear_radix_tree_dirty(struct page *page)
-{
-	BUG_ON(PagePrivate(page) || page->private);
-	set_page_writeback(page);
-	end_page_writeback(page);
-}
-
-static int __logfs_writepage(struct page *page)
-{
-	struct inode *inode = page->mapping->host;
-	int err;
-
-	err = logfs_write_buf(inode, page, WF_LOCK);
-	if (err)
-		set_page_dirty(page);
-	else
-		clear_radix_tree_dirty(page);
-	unlock_page(page);
-	return err;
-}
-
-static int logfs_writepage(struct page *page, struct writeback_control *wbc)
-{
-	struct inode *inode = page->mapping->host;
-	loff_t i_size = i_size_read(inode);
-	pgoff_t end_index = i_size >> PAGE_SHIFT;
-	unsigned offset;
-	u64 bix;
-	level_t level;
-
-	log_file("logfs_writepage(%lx, %lx, %p)\n", inode->i_ino, page->index,
-			page);
-
-	logfs_unpack_index(page->index, &bix, &level);
-
-	/* Indirect blocks are never truncated */
-	if (level != 0)
-		return __logfs_writepage(page);
-
-	/*
-	 * TODO: everything below is a near-verbatim copy of nobh_writepage().
-	 * The relevant bits should be factored out after logfs is merged.
-	 */
-
-	/* Is the page fully inside i_size? */
-	if (bix < end_index)
-		return __logfs_writepage(page);
-
-	 /* Is the page fully outside i_size? (truncate in progress) */
-	offset = i_size & (PAGE_SIZE-1);
-	if (bix > end_index || offset == 0) {
-		unlock_page(page);
-		return 0; /* don't care */
-	}
-
-	/*
-	 * The page straddles i_size.  It must be zeroed out on each and every
-	 * writepage invokation because it may be mmapped.  "A file is mapped
-	 * in multiples of the page size.  For a file that is not a multiple of
-	 * the  page size, the remaining memory is zeroed when mapped, and
-	 * writes to that region are not written out to the file."
-	 */
-	zero_user_segment(page, offset, PAGE_SIZE);
-	return __logfs_writepage(page);
-}
-
-static void logfs_invalidatepage(struct page *page, unsigned int offset,
-				 unsigned int length)
-{
-	struct logfs_block *block = logfs_block(page);
-
-	if (block->reserved_bytes) {
-		struct super_block *sb = page->mapping->host->i_sb;
-		struct logfs_super *super = logfs_super(sb);
-
-		super->s_dirty_pages -= block->reserved_bytes;
-		block->ops->free_block(sb, block);
-		BUG_ON(bitmap_weight(block->alias_map, LOGFS_BLOCK_FACTOR));
-	} else
-		move_page_to_btree(page);
-	BUG_ON(PagePrivate(page) || page->private);
-}
-
-static int logfs_releasepage(struct page *page, gfp_t only_xfs_uses_this)
-{
-	return 0; /* None of these are easy to release */
-}
-
-
-long logfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-	struct inode *inode = file_inode(file);
-	struct logfs_inode *li = logfs_inode(inode);
-	unsigned int oldflags, flags;
-	int err;
-
-	switch (cmd) {
-	case FS_IOC_GETFLAGS:
-		flags = li->li_flags & LOGFS_FL_USER_VISIBLE;
-		return put_user(flags, (int __user *)arg);
-	case FS_IOC_SETFLAGS:
-		if (IS_RDONLY(inode))
-			return -EROFS;
-
-		if (!inode_owner_or_capable(inode))
-			return -EACCES;
-
-		err = get_user(flags, (int __user *)arg);
-		if (err)
-			return err;
-
-		inode_lock(inode);
-		oldflags = li->li_flags;
-		flags &= LOGFS_FL_USER_MODIFIABLE;
-		flags |= oldflags & ~LOGFS_FL_USER_MODIFIABLE;
-		li->li_flags = flags;
-		inode_unlock(inode);
-
-		inode->i_ctime = current_time(inode);
-		mark_inode_dirty_sync(inode);
-		return 0;
-
-	default:
-		return -ENOTTY;
-	}
-}
-
-int logfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
-{
-	struct super_block *sb = file->f_mapping->host->i_sb;
-	struct inode *inode = file->f_mapping->host;
-	int ret;
-
-	ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
-	if (ret)
-		return ret;
-
-	inode_lock(inode);
-	logfs_get_wblocks(sb, NULL, WF_LOCK);
-	logfs_write_anchor(sb);
-	logfs_put_wblocks(sb, NULL, WF_LOCK);
-	inode_unlock(inode);
-
-	return 0;
-}
-
-static int logfs_setattr(struct dentry *dentry, struct iattr *attr)
-{
-	struct inode *inode = d_inode(dentry);
-	int err = 0;
-
-	err = setattr_prepare(dentry, attr);
-	if (err)
-		return err;
-
-	if (attr->ia_valid & ATTR_SIZE) {
-		err = logfs_truncate(inode, attr->ia_size);
-		if (err)
-			return err;
-	}
-
-	setattr_copy(inode, attr);
-	mark_inode_dirty(inode);
-	return 0;
-}
-
-const struct inode_operations logfs_reg_iops = {
-	.setattr	= logfs_setattr,
-};
-
-const struct file_operations logfs_reg_fops = {
-	.read_iter	= generic_file_read_iter,
-	.write_iter	= generic_file_write_iter,
-	.fsync		= logfs_fsync,
-	.unlocked_ioctl	= logfs_ioctl,
-	.llseek		= generic_file_llseek,
-	.mmap		= generic_file_readonly_mmap,
-	.open		= generic_file_open,
-};
-
-const struct address_space_operations logfs_reg_aops = {
-	.invalidatepage	= logfs_invalidatepage,
-	.readpage	= logfs_readpage,
-	.releasepage	= logfs_releasepage,
-	.set_page_dirty	= __set_page_dirty_nobuffers,
-	.writepage	= logfs_writepage,
-	.writepages	= generic_writepages,
-	.write_begin	= logfs_write_begin,
-	.write_end	= logfs_write_end,
-};

fs/logfs/gc.c

···
-/*
- * fs/logfs/gc.c	- garbage collection code
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- */
-#include "logfs.h"
-#include <linux/sched.h>
-#include <linux/slab.h>
-
-/*
- * Wear leveling needs to kick in when the difference between low erase
- * counts and high erase counts gets too big.  A good value for "too big"
- * may be somewhat below 10% of maximum erase count for the device.
- * Why not 397, to pick a nice round number with no specific meaning? :)
- *
- * WL_RATELIMIT is the minimum time between two wear level events.  A huge
- * number of segments may fulfil the requirements for wear leveling at the
- * same time.  If that happens we don't want to cause a latency from hell,
- * but just gently pick one segment every so often and minimize overhead.
- */
-#define WL_DELTA 397
-#define WL_RATELIMIT 100
-#define MAX_OBJ_ALIASES	2600
-#define SCAN_RATIO 512	/* number of scanned segments per gc'd segment */
-#define LIST_SIZE 64	/* base size of candidate lists */
-#define SCAN_ROUNDS 128	/* maximum number of complete medium scans */
-#define SCAN_ROUNDS_HIGH 4 /* maximum number of higher-level scans */
-
-static int no_free_segments(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	return super->s_free_list.count;
-}
-
-/* journal has distance -1, top-most ifile layer distance 0 */
-static u8 root_distance(struct super_block *sb, gc_level_t __gc_level)
-{
-	struct logfs_super *super = logfs_super(sb);
-	u8 gc_level = (__force u8)__gc_level;
-
-	switch (gc_level) {
-	case 0: /* fall through */
-	case 1: /* fall through */
-	case 2: /* fall through */
-	case 3:
-		/* file data or indirect blocks */
-		return super->s_ifile_levels + super->s_iblock_levels - gc_level;
-	case 6: /* fall through */
-	case 7: /* fall through */
-	case 8: /* fall through */
-	case 9:
-		/* inode file data or indirect blocks */
-		return super->s_ifile_levels - (gc_level - 6);
-	default:
-		printk(KERN_ERR"LOGFS: segment of unknown level %x found\n",
-				gc_level);
-		WARN_ON(1);
-		return super->s_ifile_levels + super->s_iblock_levels;
-	}
-}
-
-static int segment_is_reserved(struct super_block *sb, u32 segno)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_area *area;
-	void *reserved;
-	int i;
-
-	/* Some segments are reserved.  Just pretend they were all valid */
-	reserved = btree_lookup32(&super->s_reserved_segments, segno);
-	if (reserved)
-		return 1;
-
-	/* Currently open segments */
-	for_each_area(i) {
-		area = super->s_area[i];
-		if (area->a_is_open && area->a_segno == segno)
-			return 1;
-	}
-
-	return 0;
-}
-
-static void logfs_mark_segment_bad(struct super_block *sb, u32 segno)
-{
-	BUG();
-}
-
-/*
- * Returns the bytes consumed by valid objects in this segment.  Object headers
- * are counted, the segment header is not.
- */
-static u32 logfs_valid_bytes(struct super_block *sb, u32 segno, u32 *ec,
-		gc_level_t *gc_level)
-{
-	struct logfs_segment_entry se;
-	u32 ec_level;
-
-	logfs_get_segment_entry(sb, segno, &se);
-	if (se.ec_level == cpu_to_be32(BADSEG) ||
-			se.valid == cpu_to_be32(RESERVED))
-		return RESERVED;
-
-	ec_level = be32_to_cpu(se.ec_level);
-	*ec = ec_level >> 4;
-	*gc_level = GC_LEVEL(ec_level & 0xf);
-	return be32_to_cpu(se.valid);
-}
-
-static void logfs_cleanse_block(struct super_block *sb, u64 ofs, u64 ino,
-		u64 bix, gc_level_t gc_level)
-{
-	struct inode *inode;
-	int err, cookie;
-
-	inode = logfs_safe_iget(sb, ino, &cookie);
-	err = logfs_rewrite_block(inode, bix, ofs, gc_level, 0);
-	BUG_ON(err);
-	logfs_safe_iput(inode, cookie);
-}
-
-static u32 logfs_gc_segment(struct super_block *sb, u32 segno)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_segment_header sh;
-	struct logfs_object_header oh;
-	u64 ofs, ino, bix;
-	u32 seg_ofs, logical_segno, cleaned = 0;
-	int err, len, valid;
-	gc_level_t gc_level;
-
-	LOGFS_BUG_ON(segment_is_reserved(sb, segno), sb);
-
-	btree_insert32(&super->s_reserved_segments, segno, (void *)1, GFP_NOFS);
-	err = wbuf_read(sb, dev_ofs(sb, segno, 0), sizeof(sh), &sh);
-	BUG_ON(err);
-	gc_level = GC_LEVEL(sh.level);
-	logical_segno = be32_to_cpu(sh.segno);
-	if (sh.crc != logfs_crc32(&sh, sizeof(sh), 4)) {
-		logfs_mark_segment_bad(sb, segno);
-		cleaned = -1;
-		goto out;
-	}
-
-	for (seg_ofs = LOGFS_SEGMENT_HEADERSIZE;
-			seg_ofs + sizeof(oh) < super->s_segsize; ) {
-		ofs = dev_ofs(sb, logical_segno, seg_ofs);
-		err = wbuf_read(sb, dev_ofs(sb, segno, seg_ofs), sizeof(oh),
-				&oh);
-		BUG_ON(err);
-
-		if (!memchr_inv(&oh, 0xff, sizeof(oh)))
-			break;
-
-		if (oh.crc != logfs_crc32(&oh, sizeof(oh) - 4, 4)) {
-			logfs_mark_segment_bad(sb, segno);
-			cleaned = super->s_segsize - 1;
-			goto out;
-		}
-
-		ino = be64_to_cpu(oh.ino);
-		bix = be64_to_cpu(oh.bix);
-		len = sizeof(oh) + be16_to_cpu(oh.len);
-		valid = logfs_is_valid_block(sb, ofs, ino, bix, gc_level);
-		if (valid == 1) {
-			logfs_cleanse_block(sb, ofs, ino, bix, gc_level);
-			cleaned += len;
-		} else if (valid == 2) {
-			/* Will be invalid upon journal commit */
-			cleaned += len;
-		}
-		seg_ofs += len;
-	}
-out:
-	btree_remove32(&super->s_reserved_segments, segno);
-	return cleaned;
-}
-
-static struct gc_candidate *add_list(struct gc_candidate *cand,
-		struct candidate_list *list)
-{
-	struct rb_node **p = &list->rb_tree.rb_node;
-	struct rb_node *parent = NULL;
-	struct gc_candidate *cur;
-	int comp;
-
-	cand->list = list;
-	while (*p) {
-		parent = *p;
-		cur = rb_entry(parent, struct gc_candidate, rb_node);
-
-		if (list->sort_by_ec)
-			comp = cand->erase_count < cur->erase_count;
-		else
-			comp = cand->valid < cur->valid;
-
-		if (comp)
-			p = &parent->rb_left;
-		else
-			p = &parent->rb_right;
-	}
-	rb_link_node(&cand->rb_node, parent, p);
-	rb_insert_color(&cand->rb_node, &list->rb_tree);
-
-	if (list->count <= list->maxcount) {
-		list->count++;
-		return NULL;
-	}
-	cand = rb_entry(rb_last(&list->rb_tree), struct gc_candidate, rb_node);
-	rb_erase(&cand->rb_node, &list->rb_tree);
-	cand->list = NULL;
-	return cand;
-}
-
-static void remove_from_list(struct gc_candidate *cand)
-{
-	struct candidate_list *list = cand->list;
-
-	rb_erase(&cand->rb_node, &list->rb_tree);
-	list->count--;
-}
-
-static void free_candidate(struct super_block *sb, struct gc_candidate *cand)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	btree_remove32(&super->s_cand_tree, cand->segno);
-	kfree(cand);
-}
-
-u32 get_best_cand(struct super_block *sb, struct candidate_list *list, u32 *ec)
-{
-	struct gc_candidate *cand;
-	u32 segno;
-
-	BUG_ON(list->count == 0);
-
-	cand = rb_entry(rb_first(&list->rb_tree), struct gc_candidate, rb_node);
-	remove_from_list(cand);
-	segno = cand->segno;
-	if (ec)
-		*ec = cand->erase_count;
-	free_candidate(sb, cand);
-	return segno;
-}
-
-/*
- * We have several lists to manage segments with.  The reserve_list is used to
- * deal with bad blocks.  We try to keep the best (lowest ec) segments on this
- * list.
- * The free_list contains free segments for normal usage.  It usually gets the
- * second pick after the reserve_list.  But when the free_list is running short
- * it is more important to keep the free_list full than to keep a reserve.
- *
- * Segments that are not free are put onto a per-level low_list.  If we have
- * to run garbage collection, we pick a candidate from there.  All segments on
- * those lists should have at least some free space so GC will make progress.
- *
- * And last we have the ec_list, which is used to pick segments for wear
- * leveling.
- *
- * If all appropriate lists are full, we simply free the candidate and forget
- * about that segment for a while.  We have better candidates for each purpose.
- */
-static void __add_candidate(struct super_block *sb, struct gc_candidate *cand)
-{
-	struct logfs_super *super = logfs_super(sb);
-	u32 full = super->s_segsize - LOGFS_SEGMENT_RESERVE;
-
-	if (cand->valid == 0) {
-		/* 100% free segments */
-		log_gc_noisy("add reserve segment %x (ec %x) at %llx\n",
-				cand->segno, cand->erase_count,
-				dev_ofs(sb, cand->segno, 0));
-		cand = add_list(cand, &super->s_reserve_list);
-		if (cand) {
-			log_gc_noisy("add free segment %x (ec %x) at %llx\n",
-					cand->segno, cand->erase_count,
-					dev_ofs(sb, cand->segno, 0));
-			cand = add_list(cand, &super->s_free_list);
-		}
-	} else {
-		/* good candidates for Garbage Collection */
-		if (cand->valid < full)
-			cand = add_list(cand, &super->s_low_list[cand->dist]);
-		/* good candidates for wear leveling,
-		 * segments that were recently written get ignored */
-		if (cand)
-			cand = add_list(cand, &super->s_ec_list);
-	}
-	if (cand)
-		free_candidate(sb, cand);
-}
-
-static int add_candidate(struct super_block *sb, u32 segno, u32 valid, u32 ec,
-		u8 dist)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct gc_candidate *cand;
-
-	cand = kmalloc(sizeof(*cand), GFP_NOFS);
-	if (!cand)
-		return -ENOMEM;
-
-	cand->segno = segno;
-	cand->valid = valid;
-	cand->erase_count = ec;
-	cand->dist = dist;
-
-	btree_insert32(&super->s_cand_tree, segno, cand, GFP_NOFS);
-	__add_candidate(sb, cand);
-	return 0;
-}
-
-static void remove_segment_from_lists(struct super_block *sb, u32 segno)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct gc_candidate *cand;
-
-	cand = btree_lookup32(&super->s_cand_tree, segno);
-	if (cand) {
-		remove_from_list(cand);
-		free_candidate(sb, cand);
-	}
-}
-
-static void scan_segment(struct super_block *sb, u32 segno)
-{
-	u32 valid, ec = 0;
-	gc_level_t gc_level = 0;
-	u8 dist;
-
-	if (segment_is_reserved(sb, segno))
-		return;
-
-	remove_segment_from_lists(sb, segno);
-	valid = logfs_valid_bytes(sb, segno, &ec, &gc_level);
-	if (valid == RESERVED)
-		return;
-
-	dist = root_distance(sb, gc_level);
-	add_candidate(sb, segno, valid, ec, dist);
-}
-
-static struct gc_candidate *first_in_list(struct candidate_list *list)
-{
-	if (list->count == 0)
-		return NULL;
-	return rb_entry(rb_first(&list->rb_tree), struct gc_candidate, rb_node);
-}
-
-/*
- * Find the best segment for garbage collection.  Main criterion is
- * the segment requiring the least effort to clean.  Secondary
- * criterion is to GC on the lowest level available.
- *
- * So we search the least effort segment on the lowest level first,
- * then move up and pick another segment iff is requires significantly
- * less effort.  Hence the LOGFS_MAX_OBJECTSIZE in the comparison.
- */
-static struct gc_candidate *get_candidate(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int i, max_dist;
-	struct gc_candidate *cand = NULL, *this;
-
-	max_dist = min(no_free_segments(sb), LOGFS_NO_AREAS - 1);
-
-	for (i = max_dist; i >= 0; i--) {
-		this = first_in_list(&super->s_low_list[i]);
-		if (!this)
-			continue;
-		if (!cand)
-			cand = this;
-		if (this->valid + LOGFS_MAX_OBJECTSIZE <= cand->valid)
-			cand = this;
-	}
-	return cand;
-}
-
-static int __logfs_gc_once(struct super_block *sb, struct gc_candidate *cand)
-{
-	struct logfs_super *super = logfs_super(sb);
-	gc_level_t gc_level;
-	u32 cleaned, valid, segno, ec;
-	u8 dist;
-
-	if (!cand) {
-		log_gc("GC attempted, but no candidate found\n");
-		return 0;
-	}
-
-	segno = cand->segno;
-	dist = cand->dist;
-	valid = logfs_valid_bytes(sb, segno, &ec, &gc_level);
-	free_candidate(sb, cand);
-	log_gc("GC segment #%02x at %llx, %x required, %x free, %x valid, %llx free\n",
-			segno, (u64)segno << super->s_segshift,
-			dist, no_free_segments(sb), valid,
-			super->s_free_bytes);
-	cleaned = logfs_gc_segment(sb, segno);
-	log_gc("GC segment #%02x complete - now %x valid\n", segno,
-			valid - cleaned);
-	BUG_ON(cleaned != valid);
-	return 1;
-}
-
-static int logfs_gc_once(struct super_block *sb)
-{
-	struct gc_candidate *cand;
-
-	cand = get_candidate(sb);
-	if (cand)
-		remove_from_list(cand);
-	return __logfs_gc_once(sb, cand);
-}
-
-/* returns 1 if a wrap occurs, 0 otherwise */
-static int logfs_scan_some(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	u32 segno;
-	int i, ret = 0;
-
-	segno = super->s_sweeper;
-	for (i = SCAN_RATIO; i > 0; i--) {
-		segno++;
-		if (segno >= super->s_no_segs) {
-			segno = 0;
-			ret = 1;
-			/* Break out of the loop.  We want to read a single
-			 * block from the segment size on next invocation if
-			 * SCAN_RATIO is set to match block size
-			 */
-			break;
-		}
-
-		scan_segment(sb, segno);
-	}
-	super->s_sweeper = segno;
-	return ret;
-}
-
-/*
- * In principle, this function should loop forever, looking for GC candidates
- * and moving data.  LogFS is designed in such a way that this loop is
- * guaranteed to terminate.
- *
- * Limiting the loop to some iterations serves purely to catch cases when
- * these guarantees have failed.  An actual endless loop is an obvious bug
- * and should be reported as such.
- */
-static void __logfs_gc_pass(struct super_block *sb, int target)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_block *block;
-	int round, progress, last_progress = 0;
-
-	/*
-	 * Doing too many changes to the segfile at once would result
-	 * in a large number of aliases.  Write the journal before
-	 * things get out of hand.
-	 */
-	if (super->s_shadow_tree.no_shadowed_segments >= MAX_OBJ_ALIASES)
-		logfs_write_anchor(sb);
-
-	if (no_free_segments(sb) >= target &&
-			super->s_no_object_aliases < MAX_OBJ_ALIASES)
-		return;
-
-	log_gc("__logfs_gc_pass(%x)\n", target);
-	for (round = 0; round < SCAN_ROUNDS; ) {
-		if (no_free_segments(sb) >= target)
-			goto write_alias;
-
-		/* Sync in-memory state with on-medium state in case they
-		 * diverged */
-		logfs_write_anchor(sb);
-		round += logfs_scan_some(sb);
-		if (no_free_segments(sb) >= target)
-			goto write_alias;
-		progress = logfs_gc_once(sb);
-		if (progress)
-			last_progress = round;
-		else if (round - last_progress > 2)
-			break;
-		continue;
-
-		/*
-		 * The goto logic is nasty, I just don't know a better way to
-		 * code it.  GC is supposed to ensure two things:
-		 * 1. Enough free segments are available.
-		 * 2. The number of aliases is bounded.
-		 * When 1. is achieved, we take a look at 2. and write back
-		 * some alias-containing blocks, if necessary.  However, after
-		 * each such write we need to go back to 1., as writes can
-		 * consume free segments.
-		 */
-write_alias:
-		if (super->s_no_object_aliases < MAX_OBJ_ALIASES)
-			return;
-		if (list_empty(&super->s_object_alias)) {
-			/* All aliases are still in btree */
-			return;
-		}
-		log_gc("Write back one alias\n");
-		block = list_entry(super->s_object_alias.next,
-				struct logfs_block, alias_list);
-		block->ops->write_block(block);
-		/*
-		 * To round off the nasty goto logic, we reset round here.  It
-		 * is a safety-net for GC not making any progress and limited
-		 * to something reasonably small.  If incremented it for every
-		 * single alias, the loop could terminate rather quickly.
-		 */
-		round = 0;
-	}
-	LOGFS_BUG(sb);
-}
-
-static int wl_ratelimit(struct super_block *sb, u64 *next_event)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	if (*next_event < super->s_gec) {
-		*next_event = super->s_gec + WL_RATELIMIT;
-		return 0;
-	}
-	return 1;
-}
-
-static void logfs_wl_pass(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct gc_candidate *wl_cand, *free_cand;
-
-	if (wl_ratelimit(sb, &super->s_wl_gec_ostore))
-		return;
-
-	wl_cand = first_in_list(&super->s_ec_list);
-	if (!wl_cand)
-		return;
-	free_cand = first_in_list(&super->s_free_list);
-	if (!free_cand)
-		return;
-
-	if (wl_cand->erase_count < free_cand->erase_count + WL_DELTA) {
-		remove_from_list(wl_cand);
-		__logfs_gc_once(sb, wl_cand);
-	}
-}
-
-/*
- * The journal needs wear leveling as well.  But moving the journal is an
- * expensive operation so we try to avoid it as much as possible.  And if we
- * have to do it, we move the whole journal, not individual segments.
- *
- * Ratelimiting is not strictly necessary here, it mainly serves to avoid the
- * calculations.  First we check whether moving the journal would be a
- * significant improvement.  That means that a) the current journal segments
- * have more wear than the future journal segments and b) the current journal
- * segments have more wear than normal ostore segments.
- * Rationale for b) is that we don't have to move the journal if it is aging
- * less than the ostore, even if the reserve segments age even less (they are
- * excluded from wear leveling, after all).
- * Next we check that the superblocks have less wear than the journal.  Since
- * moving the journal requires writing the superblocks, we have to protect the
- * superblocks even more than the journal.
- *
- * Also we double the acceptable wear difference, compared to ostore wear
- * leveling.  Journal data is read and rewritten rapidly, comparatively.  So
- * soft errors have much less time to accumulate and we allow the journal to
- * be a bit worse than the ostore.
- */
-static void logfs_journal_wl_pass(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct gc_candidate *cand;
-	u32 min_journal_ec = -1, max_reserve_ec = 0;
-	int i;
-
-	if (wl_ratelimit(sb, &super->s_wl_gec_journal))
-		return;
-
-	if (super->s_reserve_list.count < super->s_no_journal_segs) {
-		/* Reserve is not full enough to move complete journal */
-		return;
-	}
-
-	journal_for_each(i)
-		if (super->s_journal_seg[i])
-			min_journal_ec = min(min_journal_ec,
-					super->s_journal_ec[i]);
-	cand = rb_entry(rb_first(&super->s_free_list.rb_tree),
-			struct gc_candidate, rb_node);
-	max_reserve_ec = cand->erase_count;
-	for (i = 0; i < 2; i++) {
-		struct logfs_segment_entry se;
-		u32 segno = seg_no(sb, super->s_sb_ofs[i]);
-		u32 ec;
-
-		logfs_get_segment_entry(sb, segno, &se);
-		ec = be32_to_cpu(se.ec_level) >> 4;
-		max_reserve_ec = max(max_reserve_ec, ec);
-	}
-
-	if (min_journal_ec > max_reserve_ec + 2 * WL_DELTA) {
-		do_logfs_journal_wl_pass(sb);
-	}
-}
-
-void logfs_gc_pass(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	//BUG_ON(mutex_trylock(&logfs_super(sb)->s_w_mutex));
-	/* Write journal before free space is getting saturated with dirty
-	 * objects.
-	 */
-	if (super->s_dirty_used_bytes + super->s_dirty_free_bytes
-			+ LOGFS_MAX_OBJECTSIZE >= super->s_free_bytes)
-		logfs_write_anchor(sb);
-	__logfs_gc_pass(sb, super->s_total_levels);
-	logfs_wl_pass(sb);
-	logfs_journal_wl_pass(sb);
-}
-
-static int check_area(struct super_block *sb, int i)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_area *area = super->s_area[i];
-	gc_level_t gc_level;
-	u32 cleaned, valid, ec;
-	u32 segno = area->a_segno;
-	u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
-
-	if (!area->a_is_open)
-		return 0;
-
-	if (super->s_devops->can_write_buf(sb, ofs) == 0)
-		return 0;
-
-	printk(KERN_INFO"LogFS: Possibly incomplete write at %llx\n", ofs);
-	/*
-	 * The device cannot write back the write buffer.  Most likely the
-	 * wbuf was already written out and the system crashed at some point
-	 * before the journal commit happened.  In that case we wouldn't have
-	 * to do anything.  But if the crash happened before the wbuf was
-	 * written out correctly, we must GC this segment.  So assume the
-	 * worst and always do the GC run.
-	 */
-	area->a_is_open = 0;
-	valid = logfs_valid_bytes(sb, segno, &ec, &gc_level);
-	cleaned = logfs_gc_segment(sb, segno);
-	if (cleaned != valid)
-		return -EIO;
-	return 0;
-}
-
-int logfs_check_areas(struct super_block *sb)
-{
-	int i, err;
-
-	for_each_area(i) {
-		err = check_area(sb, i);
-		if (err)
-			return err;
-	}
-	return 0;
-}
-
-static void logfs_init_candlist(struct candidate_list *list, int maxcount,
-		int sort_by_ec)
-{
-	list->count = 0;
-	list->maxcount = maxcount;
-	list->sort_by_ec = sort_by_ec;
-	list->rb_tree = RB_ROOT;
-}
-
-int logfs_init_gc(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int i;
-
-	btree_init_mempool32(&super->s_cand_tree, super->s_btree_pool);
-	logfs_init_candlist(&super->s_free_list, LIST_SIZE + SCAN_RATIO, 1);
-	logfs_init_candlist(&super->s_reserve_list,
-			super->s_bad_seg_reserve, 1);
-	for_each_area(i)
-		logfs_init_candlist(&super->s_low_list[i], LIST_SIZE, 0);
-	logfs_init_candlist(&super->s_ec_list, LIST_SIZE, 1);
-	return 0;
-}
-
-static void logfs_cleanup_list(struct super_block *sb,
-		struct candidate_list *list)
-{
-	struct gc_candidate *cand;
-
-	while (list->count) {
-		cand = rb_entry(list->rb_tree.rb_node, struct gc_candidate,
-				rb_node);
-		remove_from_list(cand);
-		free_candidate(sb, cand);
-	}
-	BUG_ON(list->rb_tree.rb_node);
-}
-
-void logfs_cleanup_gc(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int i;
-
-	if (!super->s_free_list.count)
-		return;
-
-	/*
-	 * FIXME: The btree may still contain a single empty node.  So we
-	 * call the grim visitor to clean up that mess.  Btree code should
-	 * do it for us, really.
-	 */
-	btree_grim_visitor32(&super->s_cand_tree, 0, NULL);
-	logfs_cleanup_list(sb, &super->s_free_list);
-	logfs_cleanup_list(sb, &super->s_reserve_list);
-	for_each_area(i)
-		logfs_cleanup_list(sb, &super->s_low_list[i]);
-	logfs_cleanup_list(sb, &super->s_ec_list);
-}

fs/logfs/inode.c

···
-/*
- * fs/logfs/inode.c	- inode handling code
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- */
-#include "logfs.h"
-#include <linux/slab.h>
-#include <linux/writeback.h>
-#include <linux/backing-dev.h>
-
-/*
- * How soon to reuse old inode numbers?  LogFS doesn't store deleted inodes
- * on the medium.  It therefore also lacks a method to store the previous
- * generation number for deleted inodes.  Instead a single generation number
- * is stored which will be used for new inodes.  Being just a 32bit counter,
- * this can obvious wrap relatively quickly.  So we only reuse inodes if we
- * know that a fair number of inodes can be created before we have to increment
- * the generation again - effectively adding some bits to the counter.
- * But being too aggressive here means we keep a very large and very sparse
- * inode file, wasting space on indirect blocks.
- * So what is a good value?  Beats me.  64k seems moderately bad on both
- * fronts, so let's use that for now...
- *
- * NFS sucks, as everyone already knows.
- */
-#define INOS_PER_WRAP (0x10000)
-
-/*
- * Logfs' requirement to read inodes for garbage collection makes life a bit
- * harder.  GC may have to read inodes that are in I_FREEING state, when they
- * are being written out - and waiting for GC to make progress, naturally.
- *
- * So we cannot just call iget() or some variant of it, but first have to check
- * whether the inode in question might be in I_FREEING state.  Therefore we
- * maintain our own per-sb list of "almost deleted" inodes and check against
- * that list first.  Normally this should be at most 1-2 entries long.
- *
- * Also, inodes have logfs-specific reference counting on top of what the vfs
- * does.  When .destroy_inode is called, normally the reference count will drop
- * to zero and the inode gets deleted.  But if GC accessed the inode, its
- * refcount will remain nonzero and final deletion will have to wait.
- *
- * As a result we have two sets of functions to get/put inodes:
- * logfs_safe_iget/logfs_safe_iput	- safe to call from GC context
- * logfs_iget/iput			- normal version
- */
-static struct kmem_cache *logfs_inode_cache;
-
-static DEFINE_SPINLOCK(logfs_inode_lock);
-
-static void logfs_inode_setops(struct inode *inode)
-{
-	switch (inode->i_mode & S_IFMT) {
-	case S_IFDIR:
-		inode->i_op = &logfs_dir_iops;
-		inode->i_fop = &logfs_dir_fops;
-		inode->i_mapping->a_ops = &logfs_reg_aops;
-		break;
-	case S_IFREG:
-		inode->i_op = &logfs_reg_iops;
-		inode->i_fop = &logfs_reg_fops;
-		inode->i_mapping->a_ops = &logfs_reg_aops;
-		break;
-	case S_IFLNK:
-		inode->i_op = &page_symlink_inode_operations;
-		inode_nohighmem(inode);
-		inode->i_mapping->a_ops = &logfs_reg_aops;
-		break;
-	case S_IFSOCK:	/* fall through */
-	case S_IFBLK:	/* fall through */
-	case S_IFCHR:	/* fall through */
-	case S_IFIFO:
-		init_special_inode(inode, inode->i_mode, inode->i_rdev);
-		break;
-	default:
-		BUG();
-	}
-}
-
-static struct inode *__logfs_iget(struct super_block *sb, ino_t ino)
-{
-	struct inode *inode = iget_locked(sb, ino);
-	int err;
-
-	if (!inode)
-		return ERR_PTR(-ENOMEM);
-	if (!(inode->i_state & I_NEW))
-		return inode;
-
-	err = logfs_read_inode(inode);
-	if (err || inode->i_nlink == 0) {
-		/* inode->i_nlink == 0 can be true when called from
-		 * block validator */
-		/* set i_nlink to 0 to prevent caching */
-		clear_nlink(inode);
-		logfs_inode(inode)->li_flags |= LOGFS_IF_ZOMBIE;
-		iget_failed(inode);
-		if (!err)
-			err = -ENOENT;
-		return ERR_PTR(err);
-	}
-
-	logfs_inode_setops(inode);
-	unlock_new_inode(inode);
-	return inode;
-}
-
-struct inode *logfs_iget(struct super_block *sb, ino_t ino)
-{
-	BUG_ON(ino == LOGFS_INO_MASTER);
-	BUG_ON(ino == LOGFS_INO_SEGFILE);
-	return __logfs_iget(sb, ino);
-}
-
-/*
- * is_cached is set to 1 if we hand out a cached inode, 0 otherwise.
- * this allows logfs_iput to do the right thing later
- */
-struct inode *logfs_safe_iget(struct super_block *sb, ino_t ino, int *is_cached)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_inode *li;
-
-	if (ino == LOGFS_INO_MASTER)
-		return super->s_master_inode;
-	if (ino == LOGFS_INO_SEGFILE)
-		return super->s_segfile_inode;
-
-	spin_lock(&logfs_inode_lock);
-	list_for_each_entry(li, &super->s_freeing_list, li_freeing_list)
-		if (li->vfs_inode.i_ino == ino) {
-			li->li_refcount++;
-			spin_unlock(&logfs_inode_lock);
-			*is_cached = 1;
-			return &li->vfs_inode;
-		}
-	spin_unlock(&logfs_inode_lock);
-
-	*is_cached = 0;
-	return __logfs_iget(sb, ino);
-}
-
-static void logfs_i_callback(struct rcu_head *head)
-{
-	struct inode *inode = container_of(head, struct inode, i_rcu);
-	kmem_cache_free(logfs_inode_cache, logfs_inode(inode));
-}
-
-static void __logfs_destroy_inode(struct inode *inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-
-	BUG_ON(li->li_block);
-	list_del(&li->li_freeing_list);
-	call_rcu(&inode->i_rcu, logfs_i_callback);
-}
-
-static void __logfs_destroy_meta_inode(struct inode *inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	BUG_ON(li->li_block);
-	call_rcu(&inode->i_rcu, logfs_i_callback);
-}
-
-static void logfs_destroy_inode(struct inode *inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-
-	if (inode->i_ino < LOGFS_RESERVED_INOS) {
-		/*
-		 * The reserved inodes are never destroyed unless we are in
-		 * unmont path.
-		 */
-		__logfs_destroy_meta_inode(inode);
-		return;
-	}
-
-	BUG_ON(list_empty(&li->li_freeing_list));
-	spin_lock(&logfs_inode_lock);
-	li->li_refcount--;
-	if (li->li_refcount == 0)
-		__logfs_destroy_inode(inode);
-	spin_unlock(&logfs_inode_lock);
-}
-
-void logfs_safe_iput(struct inode *inode, int is_cached)
-{
-	if (inode->i_ino == LOGFS_INO_MASTER)
-		return;
-	if (inode->i_ino == LOGFS_INO_SEGFILE)
-		return;
-
-	if (is_cached) {
-		logfs_destroy_inode(inode);
-		return;
-	}
-
-	iput(inode);
-}
-
-static void logfs_init_inode(struct super_block *sb, struct inode *inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	int i;
-
-	li->li_flags	= 0;
-	li->li_height	= 0;
-	li->li_used_bytes = 0;
-	li->li_block	= NULL;
-	i_uid_write(inode, 0);
-	i_gid_write(inode, 0);
-	inode->i_size	= 0;
-	inode->i_blocks	= 0;
-	inode->i_ctime	= current_time(inode);
-	inode->i_mtime	= current_time(inode);
-	li->li_refcount = 1;
-	INIT_LIST_HEAD(&li->li_freeing_list);
-
-	for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
-		li->li_data[i] = 0;
-
-	return;
-}
-
-static struct inode *logfs_alloc_inode(struct super_block *sb)
-{
-	struct logfs_inode *li;
-
-	li = kmem_cache_alloc(logfs_inode_cache, GFP_NOFS);
-	if (!li)
-		return NULL;
-	logfs_init_inode(sb, &li->vfs_inode);
-	return &li->vfs_inode;
-}
-
-/*
- * In logfs inodes are written to an inode file.  The inode file, like any
- * other file, is managed with a inode.  The inode file's inode, aka master
- * inode, requires special handling in several respects.  First, it cannot be
- * written to the inode file, so it is stored in the journal instead.
- *
- * Secondly, this inode cannot be written back and destroyed before all other
- * inodes have been written.  The ordering is important.  Linux' VFS is happily
- * unaware of the ordering constraint and would ordinarily destroy the master
- * inode at umount time while other inodes are still in use and dirty.  Not
- * good.
- *
- * So logfs makes sure the master inode is not written until all other inodes
- * have been destroyed.  Sadly, this method has another side-effect.  The VFS
- * will notice one remaining inode and print a frightening warning message.
- * Worse, it is impossible to judge whether such a warning was caused by the
- * master inode or any other inodes have leaked as well.
- *
- * Our attempt of solving this is with logfs_new_meta_inode() below.  Its
- * purpose is to create a new inode that will not trigger the warning if such
- * an inode is still in use.  An ugly hack, no doubt.  Suggections for
- * improvement are welcome.
- *
- * AV: that's what ->put_super() is for...
- */
-struct inode *logfs_new_meta_inode(struct super_block *sb, u64 ino)
-{
-	struct inode *inode;
-
-	inode = new_inode(sb);
-	if (!inode)
-		return ERR_PTR(-ENOMEM);
-
-	inode->i_mode = S_IFREG;
-	inode->i_ino = ino;
-	inode->i_data.a_ops = &logfs_reg_aops;
-	mapping_set_gfp_mask(&inode->i_data, GFP_NOFS);
-
-	return inode;
-}
-
-struct inode *logfs_read_meta_inode(struct super_block *sb, u64 ino)
-{
-	struct inode *inode;
-	int err;
-
-	inode = logfs_new_meta_inode(sb, ino);
-	if (IS_ERR(inode))
-		return inode;
-
-	err = logfs_read_inode(inode);
-	if (err) {
-		iput(inode);
-		return ERR_PTR(err);
-	}
-	logfs_inode_setops(inode);
-	return inode;
-}
-
-static int logfs_write_inode(struct inode *inode, struct writeback_control *wbc)
-{
-	int ret;
-	long flags = WF_LOCK;
-
-	/* Can only happen if creat() failed.  Safe to skip. */
-	if (logfs_inode(inode)->li_flags & LOGFS_IF_STILLBORN)
-		return 0;
-
-	ret = __logfs_write_inode(inode, NULL, flags);
-	LOGFS_BUG_ON(ret, inode->i_sb);
-	return ret;
-}
-
-/* called with inode->i_lock held */
-static int logfs_drop_inode(struct inode *inode)
-{
-	struct logfs_super *super = logfs_super(inode->i_sb);
-	struct logfs_inode *li = logfs_inode(inode);
-
-	spin_lock(&logfs_inode_lock);
-	list_move(&li->li_freeing_list, &super->s_freeing_list);
-	spin_unlock(&logfs_inode_lock);
-	return generic_drop_inode(inode);
-}
-
-static void logfs_set_ino_generation(struct super_block *sb,
-		struct inode *inode)
-{
-	struct logfs_super *super = logfs_super(sb);
-	u64 ino;
-
-	mutex_lock(&super->s_journal_mutex);
-	ino = logfs_seek_hole(super->s_master_inode, super->s_last_ino + 1);
-	super->s_last_ino = ino;
-	super->s_inos_till_wrap--;
-	if (super->s_inos_till_wrap < 0) {
-		super->s_last_ino = LOGFS_RESERVED_INOS;
-		super->s_generation++;
-		super->s_inos_till_wrap = INOS_PER_WRAP;
-	}
-	inode->i_ino = ino;
-	inode->i_generation = super->s_generation;
-	mutex_unlock(&super->s_journal_mutex);
-}
-
-struct inode *logfs_new_inode(struct inode *dir, umode_t mode)
-{
-	struct super_block *sb = dir->i_sb;
-	struct inode *inode;
-
-	inode = new_inode(sb);
-	if (!inode)
-		return ERR_PTR(-ENOMEM);
-
-	logfs_init_inode(sb, inode);
-
-	/* inherit parent flags */
-	logfs_inode(inode)->li_flags |=
-		logfs_inode(dir)->li_flags & LOGFS_FL_INHERITED;
-
-	inode->i_mode = mode;
-	logfs_set_ino_generation(sb, inode);
-
-	inode_init_owner(inode, dir, mode);
-	logfs_inode_setops(inode);
-	insert_inode_hash(inode);
-
-	return inode;
-}
-
-static void logfs_init_once(void *_li)
-{
-	struct logfs_inode *li = _li;
-	int i;
-
-	li->li_flags = 0;
-	li->li_used_bytes = 0;
-	li->li_refcount = 1;
-	for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
-		li->li_data[i] = 0;
-	inode_init_once(&li->vfs_inode);
-}
-
-static int logfs_sync_fs(struct super_block *sb, int wait)
-{
-	logfs_get_wblocks(sb, NULL, WF_LOCK);
-	logfs_write_anchor(sb);
-	logfs_put_wblocks(sb, NULL, WF_LOCK);
-	return 0;
-}
-
-static void logfs_put_super(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	/* kill the meta-inodes */
-	iput(super->s_segfile_inode);
-	iput(super->s_master_inode);
-	iput(super->s_mapping_inode);
-}
-
-const struct super_operations logfs_super_operations = {
-	.alloc_inode	= logfs_alloc_inode,
-	.destroy_inode	= logfs_destroy_inode,
-	.evict_inode	= logfs_evict_inode,
-	.drop_inode	= logfs_drop_inode,
-	.put_super	= logfs_put_super,
-	.write_inode	= logfs_write_inode,
-	.statfs		= logfs_statfs,
-	.sync_fs	= logfs_sync_fs,
-};
-
-int logfs_init_inode_cache(void)
-{
-	logfs_inode_cache = kmem_cache_create("logfs_inode_cache",
-			sizeof(struct logfs_inode), 0,
-			SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
-			logfs_init_once);
-	if (!logfs_inode_cache)
-		return -ENOMEM;
-	return 0;
-}
-
-void logfs_destroy_inode_cache(void)
-{
-	/*
-	 * Make sure all delayed rcu free inodes are flushed before we
-	 * destroy cache.
-	 */
-	rcu_barrier();
-	kmem_cache_destroy(logfs_inode_cache);
-}

fs/logfs/journal.c

···
-/*
- * fs/logfs/journal.c	- journal handling code
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- */
-#include "logfs.h"
-#include <linux/slab.h>
-
-static void logfs_calc_free(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	u64 reserve, no_segs = super->s_no_segs;
-	s64 free;
-	int i;
-
-	/* superblock segments */
-	no_segs -= 2;
-	super->s_no_journal_segs = 0;
-	/* journal */
-	journal_for_each(i)
-		if (super->s_journal_seg[i]) {
-			no_segs--;
-			super->s_no_journal_segs++;
-		}
-
-	/* open segments plus one extra per level for GC */
-	no_segs -= 2 * super->s_total_levels;
-
-	free = no_segs * (super->s_segsize - LOGFS_SEGMENT_RESERVE);
-	free -= super->s_used_bytes;
-	/* just a bit extra */
-	free -= super->s_total_levels * 4096;
-
-	/* Bad blocks are 'paid' for with speed reserve - the filesystem
-	 * simply gets slower as bad blocks accumulate.  Until the bad blocks
-	 * exceed the speed reserve - then the filesystem gets smaller.
-	 */
-	reserve = super->s_bad_segments + super->s_bad_seg_reserve;
-	reserve *= super->s_segsize - LOGFS_SEGMENT_RESERVE;
-	reserve = max(reserve, super->s_speed_reserve);
-	free -= reserve;
-	if (free < 0)
-		free = 0;
-
-	super->s_free_bytes = free;
-}
-
-static void reserve_sb_and_journal(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct btree_head32 *head = &super->s_reserved_segments;
-	int i, err;
-
-	err = btree_insert32(head, seg_no(sb, super->s_sb_ofs[0]), (void *)1,
-			GFP_KERNEL);
-	BUG_ON(err);
-
-	err = btree_insert32(head, seg_no(sb, super->s_sb_ofs[1]), (void *)1,
-			GFP_KERNEL);
-	BUG_ON(err);
-
-	journal_for_each(i) {
-		if (!super->s_journal_seg[i])
-			continue;
-		err = btree_insert32(head, super->s_journal_seg[i], (void *)1,
-				GFP_KERNEL);
-		BUG_ON(err);
-	}
-}
-
-static void read_dynsb(struct super_block *sb,
-		struct logfs_je_dynsb *dynsb)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	super->s_gec		= be64_to_cpu(dynsb->ds_gec);
-	super->s_sweeper	= be64_to_cpu(dynsb->ds_sweeper);
-	super->s_victim_ino	= be64_to_cpu(dynsb->ds_victim_ino);
-	super->s_rename_dir	= be64_to_cpu(dynsb->ds_rename_dir);
-	super->s_rename_pos	= be64_to_cpu(dynsb->ds_rename_pos);
-	super->s_used_bytes	= be64_to_cpu(dynsb->ds_used_bytes);
-	super->s_generation	= be32_to_cpu(dynsb->ds_generation);
-}
-
-static void read_anchor(struct super_block *sb,
-		struct logfs_je_anchor *da)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct inode *inode = super->s_master_inode;
-	struct logfs_inode *li = logfs_inode(inode);
-	int i;
-
-	super->s_last_ino = be64_to_cpu(da->da_last_ino);
-	li->li_flags	= 0;
-	li->li_height	= da->da_height;
-	i_size_write(inode, be64_to_cpu(da->da_size));
-	li->li_used_bytes = be64_to_cpu(da->da_used_bytes);
-
-	for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
-		li->li_data[i] = be64_to_cpu(da->da_data[i]);
-}
-
-static void read_erasecount(struct super_block *sb,
-		struct logfs_je_journal_ec *ec)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int i;
-
-	journal_for_each(i)
-		super->s_journal_ec[i] = be32_to_cpu(ec->ec[i]);
-}
-
-static int read_area(struct super_block *sb, struct logfs_je_area *a)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_area *area = super->s_area[a->gc_level];
-	u64 ofs;
-	u32 writemask = ~(super->s_writesize - 1);
-
-	if (a->gc_level >= LOGFS_NO_AREAS)
-		return -EIO;
-	if (a->vim != VIM_DEFAULT)
-		return -EIO; /* TODO: close area and continue */
-
-	area->a_used_bytes = be32_to_cpu(a->used_bytes);
-	area->a_written_bytes = area->a_used_bytes & writemask;
-	area->a_segno = be32_to_cpu(a->segno);
-	if (area->a_segno)
-		area->a_is_open = 1;
-
-	ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
-	if (super->s_writesize > 1)
-		return logfs_buf_recover(area, ofs, a + 1, super->s_writesize);
-	else
-		return logfs_buf_recover(area, ofs, NULL, 0);
-}
-
-static void *unpack(void *from, void *to)
-{
-	struct logfs_journal_header *jh = from;
-	void *data = from + sizeof(struct logfs_journal_header);
-	int err;
-	size_t inlen, outlen;
-
-	inlen = be16_to_cpu(jh->h_len);
-	outlen = be16_to_cpu(jh->h_datalen);
-
-	if (jh->h_compr == COMPR_NONE)
-		memcpy(to, data, inlen);
-	else {
-		err = logfs_uncompress(data, to, inlen, outlen);
-		BUG_ON(err);
-	}
-	return to;
-}
-
-static int __read_je_header(struct super_block *sb, u64 ofs,
-		struct logfs_journal_header *jh)
-{
-	struct logfs_super *super = logfs_super(sb);
-	size_t bufsize = max_t(size_t, sb->s_blocksize, super->s_writesize)
-		+ MAX_JOURNAL_HEADER;
-	u16 type, len, datalen;
-	int err;
-
-	/* read header only */
-	err = wbuf_read(sb, ofs, sizeof(*jh), jh);
-	if (err)
-		return err;
-	type = be16_to_cpu(jh->h_type);
-	len = be16_to_cpu(jh->h_len);
-	datalen = be16_to_cpu(jh->h_datalen);
-	if (len > sb->s_blocksize)
-		return -EIO;
-	if ((type < JE_FIRST) || (type > JE_LAST))
-		return -EIO;
-	if (datalen > bufsize)
-		return -EIO;
-	return 0;
-}
-
-static int __read_je_payload(struct super_block *sb, u64 ofs,
-		struct logfs_journal_header *jh)
-{
-	u16 len;
-	int err;
-
-	len = be16_to_cpu(jh->h_len);
-	err = wbuf_read(sb, ofs + sizeof(*jh), len, jh + 1);
-	if (err)
-		return err;
-	if (jh->h_crc != logfs_crc32(jh, len + sizeof(*jh), 4)) {
-		/* Old code was confused.  It forgot about the header length
-		 * and stopped calculating the crc 16 bytes before the end
-		 * of data - ick!
-		 * FIXME: Remove this hack once the old code is fixed.
-		 */
-		if (jh->h_crc == logfs_crc32(jh, len, 4))
-			WARN_ON_ONCE(1);
-		else
-			return -EIO;
-	}
-	return 0;
-}
-
-/*
- * jh needs to be large enough to hold the complete entry, not just the header
- */
-static int __read_je(struct super_block *sb, u64 ofs,
-		struct logfs_journal_header *jh)
-{
-	int err;
-
-	err = __read_je_header(sb, ofs, jh);
-	if (err)
-		return err;
-	return __read_je_payload(sb, ofs, jh);
-}
-
-static int read_je(struct super_block *sb, u64 ofs)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_journal_header *jh = super->s_compressed_je;
-	void *scratch = super->s_je;
-	u16 type, datalen;
-	int err;
-
-	err = __read_je(sb, ofs, jh);
-	if (err)
-		return err;
-	type = be16_to_cpu(jh->h_type);
-	datalen = be16_to_cpu(jh->h_datalen);
-
-	switch (type) {
-	case JE_DYNSB:
-		read_dynsb(sb, unpack(jh, scratch));
-		break;
-	case JE_ANCHOR:
-		read_anchor(sb, unpack(jh, scratch));
-		break;
-	case JE_ERASECOUNT:
-		read_erasecount(sb, unpack(jh, scratch));
-		break;
-	case JE_AREA:
-		err = read_area(sb, unpack(jh, scratch));
-		break;
-	case JE_OBJ_ALIAS:
-		err = logfs_load_object_aliases(sb, unpack(jh, scratch),
-				datalen);
-		break;
-	default:
-		WARN_ON_ONCE(1);
-		return -EIO;
-	}
-	return err;
-}
-
-static int logfs_read_segment(struct super_block *sb, u32 segno)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_journal_header *jh = super->s_compressed_je;
-	u64 ofs, seg_ofs = dev_ofs(sb, segno, 0);
-	u32 h_ofs, last_ofs = 0;
-	u16 len, datalen, last_len = 0;
-	int i, err;
-
-	/* search for most recent commit */
-	for (h_ofs = 0; h_ofs < super->s_segsize; h_ofs += sizeof(*jh)) {
-		ofs = seg_ofs + h_ofs;
-		err = __read_je_header(sb, ofs, jh);
-		if (err)
-			continue;
-		if (jh->h_type != cpu_to_be16(JE_COMMIT))
-			continue;
-		err = __read_je_payload(sb, ofs, jh);
-		if (err)
-			continue;
-		len = be16_to_cpu(jh->h_len);
-		datalen = be16_to_cpu(jh->h_datalen);
-		if ((datalen > sizeof(super->s_je_array)) ||
-				(datalen % sizeof(__be64)))
-			continue;
-		last_ofs = h_ofs;
-		last_len = datalen;
-		h_ofs += ALIGN(len, sizeof(*jh)) - sizeof(*jh);
-	}
-	/* read commit */
-	if (last_ofs == 0)
-		return -ENOENT;
-	ofs = seg_ofs + last_ofs;
-	log_journal("Read commit from %llx\n", ofs);
-	err = __read_je(sb, ofs, jh);
-	BUG_ON(err); /* We should have caught it in the scan loop already */
-	if (err)
-		return err;
-	/* uncompress */
-	unpack(jh, super->s_je_array);
-	super->s_no_je = last_len / sizeof(__be64);
-	/* iterate over array */
-	for (i = 0; i < super->s_no_je; i++) {
-		err = read_je(sb, be64_to_cpu(super->s_je_array[i]));
-		if (err)
-			return err;
-	}
-	super->s_journal_area->a_segno = segno;
-	return 0;
-}
-
-static u64 read_gec(struct super_block *sb, u32 segno)
-{
-	struct logfs_segment_header sh;
-	__be32 crc;
-	int err;
-
-	if (!segno)
-		return 0;
-	err = wbuf_read(sb, dev_ofs(sb, segno, 0), sizeof(sh), &sh);
-	if (err)
-		return 0;
-	crc = logfs_crc32(&sh, sizeof(sh), 4);
-	if (crc != sh.crc) {
-		WARN_ON(sh.gec != cpu_to_be64(0xffffffffffffffffull));
-		/* Most likely it was just erased */
-		return 0;
-	}
-	return be64_to_cpu(sh.gec);
-}
-
-static int logfs_read_journal(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	u64 gec[LOGFS_JOURNAL_SEGS], max;
-	u32 segno;
-	int i, max_i;
-
-	max = 0;
-	max_i = -1;
-	journal_for_each(i) {
-		segno = super->s_journal_seg[i];
-		gec[i] = read_gec(sb, super->s_journal_seg[i]);
-		if (gec[i] > max) {
-			max = gec[i];
-			max_i = i;
-		}
-	}
-	if (max_i == -1)
-		return -EIO;
-	/* FIXME: Try older segments in case of error */
-	return logfs_read_segment(sb, super->s_journal_seg[max_i]);
-}
-
-/*
- * First search the current segment (outer loop), then pick the next segment
- * in the array, skipping any zero entries (inner loop).
- */
-static void journal_get_free_segment(struct logfs_area *area)
-{
-	struct logfs_super *super = logfs_super(area->a_sb);
-	int i;
-
-	journal_for_each(i) {
-		if (area->a_segno != super->s_journal_seg[i])
-			continue;
-
-		do {
-			i++;
-			if (i == LOGFS_JOURNAL_SEGS)
-				i = 0;
-		} while (!super->s_journal_seg[i]);
-
-		area->a_segno = super->s_journal_seg[i];
-		area->a_erase_count = ++(super->s_journal_ec[i]);
-		log_journal("Journal now at %x (ec %x)\n", area->a_segno,
-				area->a_erase_count);
-		return;
-	}
-	BUG();
-}
-
-static void journal_get_erase_count(struct logfs_area *area)
-{
-	/* erase count is stored globally and incremented in
-	 * journal_get_free_segment() - nothing to do here */
-}
-
-static int journal_erase_segment(struct logfs_area *area)
-{
-	struct super_block *sb = area->a_sb;
-	union {
-		struct logfs_segment_header sh;
-		unsigned char c[ALIGN(sizeof(struct logfs_segment_header), 16)];
-	} u;
-	u64 ofs;
-	int err;
-
-	err = logfs_erase_segment(sb, area->a_segno, 1);
-	if (err)
-		return err;
-
-	memset(&u, 0, sizeof(u));
-	u.sh.pad = 0;
-	u.sh.type = SEG_JOURNAL;
-	u.sh.level = 0;
-	u.sh.segno = cpu_to_be32(area->a_segno);
-	u.sh.ec = cpu_to_be32(area->a_erase_count);
-	u.sh.gec = cpu_to_be64(logfs_super(sb)->s_gec);
-	u.sh.crc = logfs_crc32(&u.sh, sizeof(u.sh), 4);
-
-	/* This causes a bug in segment.c.  Not yet. */
-	//logfs_set_segment_erased(sb, area->a_segno, area->a_erase_count, 0);
-
-	ofs = dev_ofs(sb, area->a_segno, 0);
-	area->a_used_bytes = sizeof(u);
-	logfs_buf_write(area, ofs, &u, sizeof(u));
-	return 0;
-}
-
-static size_t __logfs_write_header(struct logfs_super *super,
-		struct logfs_journal_header *jh, size_t len, size_t datalen,
-		u16 type, u8 compr)
-{
-	jh->h_len	= cpu_to_be16(len);
-	jh->h_type	= cpu_to_be16(type);
-	jh->h_datalen	= cpu_to_be16(datalen);
-	jh->h_compr	= compr;
-	jh->h_pad[0]	= 'H';
-	jh->h_pad[1]	= 'E';
-	jh->h_pad[2]	= 'A';
-	jh->h_pad[3]	= 'D';
-	jh->h_pad[4]	= 'R';
-	jh->h_crc	= logfs_crc32(jh, len + sizeof(*jh), 4);
-	return ALIGN(len, 16) + sizeof(*jh);
-}
-
-static size_t logfs_write_header(struct logfs_super *super,
-		struct logfs_journal_header *jh, size_t datalen, u16 type)
-{
-	size_t len = datalen;
-
-	return __logfs_write_header(super, jh, len, datalen, type, COMPR_NONE);
-}
-
-static inline size_t logfs_journal_erasecount_size(struct logfs_super *super)
-{
-	return LOGFS_JOURNAL_SEGS * sizeof(__be32);
-}
-
-static void *logfs_write_erasecount(struct super_block *sb, void *_ec,
-		u16 *type, size_t *len)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_je_journal_ec *ec = _ec;
-	int i;
-
-	journal_for_each(i)
-		ec->ec[i] = cpu_to_be32(super->s_journal_ec[i]);
-	*type = JE_ERASECOUNT;
-	*len = logfs_journal_erasecount_size(super);
-	return ec;
-}
-
-static void account_shadow(void *_shadow, unsigned long _sb, u64 ignore,
-		size_t ignore2)
-{
-	struct logfs_shadow *shadow = _shadow;
-	struct super_block *sb = (void *)_sb;
-	struct logfs_super *super = logfs_super(sb);
-
-	/* consume new space */
-	super->s_free_bytes	  -= shadow->new_len;
-	super->s_used_bytes	  += shadow->new_len;
-	super->s_dirty_used_bytes -= shadow->new_len;
-
-	/* free up old space */
-	super->s_free_bytes	  += shadow->old_len;
-	super->s_used_bytes	  -= shadow->old_len;
-	super->s_dirty_free_bytes -= shadow->old_len;
-
-	logfs_set_segment_used(sb, shadow->old_ofs, -shadow->old_len);
-	logfs_set_segment_used(sb, shadow->new_ofs, shadow->new_len);
-
-	log_journal("account_shadow(%llx, %llx, %x) %llx->%llx %x->%x\n",
-			shadow->ino, shadow->bix, shadow->gc_level,
-			shadow->old_ofs, shadow->new_ofs,
-			shadow->old_len, shadow->new_len);
-	mempool_free(shadow, super->s_shadow_pool);
-}
-
-static void account_shadows(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct inode *inode = super->s_master_inode;
-	struct logfs_inode *li = logfs_inode(inode);
-	struct shadow_tree *tree = &super->s_shadow_tree;
-
-	btree_grim_visitor64(&tree->new, (unsigned long)sb, account_shadow);
-	btree_grim_visitor64(&tree->old, (unsigned long)sb, account_shadow);
-	btree_grim_visitor32(&tree->segment_map, 0, NULL);
-	tree->no_shadowed_segments = 0;
-
-	if (li->li_block) {
-		/*
-		 * We never actually use the structure, when attached to the
-		 * master inode.  But it is easier to always free it here than
-		 * to have checks in several places elsewhere when allocating
-		 * it.
-		 */
-		li->li_block->ops->free_block(sb, li->li_block);
-	}
-	BUG_ON((s64)li->li_used_bytes < 0);
-}
-
-static void *__logfs_write_anchor(struct super_block *sb, void *_da,
-		u16 *type, size_t *len)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_je_anchor *da = _da;
-	struct inode *inode = super->s_master_inode;
-	struct logfs_inode *li = logfs_inode(inode);
-	int i;
-
-	da->da_height	= li->li_height;
-	da->da_last_ino = cpu_to_be64(super->s_last_ino);
-	da->da_size	= cpu_to_be64(i_size_read(inode));
-	da->da_used_bytes = cpu_to_be64(li->li_used_bytes);
-	for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
-		da->da_data[i] = cpu_to_be64(li->li_data[i]);
-	*type = JE_ANCHOR;
-	*len = sizeof(*da);
-	return da;
-}
-
-static void *logfs_write_dynsb(struct super_block *sb, void *_dynsb,
-		u16 *type, size_t *len)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_je_dynsb *dynsb = _dynsb;
-
-	dynsb->ds_gec		= cpu_to_be64(super->s_gec);
-	dynsb->ds_sweeper	= cpu_to_be64(super->s_sweeper);
-	dynsb->ds_victim_ino	= cpu_to_be64(super->s_victim_ino);
-	dynsb->ds_rename_dir	= cpu_to_be64(super->s_rename_dir);
-	dynsb->ds_rename_pos	= cpu_to_be64(super->s_rename_pos);
-	dynsb->ds_used_bytes	= cpu_to_be64(super->s_used_bytes);
-	dynsb->ds_generation	= cpu_to_be32(super->s_generation);
-	*type = JE_DYNSB;
-	*len = sizeof(*dynsb);
-	return dynsb;
-}
-
-static void write_wbuf(struct super_block *sb, struct logfs_area *area,
-		void *wbuf)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct address_space *mapping = super->s_mapping_inode->i_mapping;
-	u64 ofs;
-	pgoff_t index;
-	int page_ofs;
-	struct page *page;
-
-	ofs = dev_ofs(sb, area->a_segno,
-			area->a_used_bytes & ~(super->s_writesize - 1));
-	index = ofs >> PAGE_SHIFT;
-	page_ofs = ofs & (PAGE_SIZE - 1);
-
-	page = find_or_create_page(mapping, index, GFP_NOFS);
-	BUG_ON(!page);
-	memcpy(wbuf, page_address(page) + page_ofs, super->s_writesize);
-	unlock_page(page);
-}
-
-static void *logfs_write_area(struct super_block *sb, void *_a,
-		u16 *type, size_t *len)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_area *area = super->s_area[super->s_sum_index];
-	struct logfs_je_area *a = _a;
-
-	a->vim = VIM_DEFAULT;
-	a->gc_level = super->s_sum_index;
-	a->used_bytes = cpu_to_be32(area->a_used_bytes);
-	a->segno = cpu_to_be32(area->a_segno);
-	if (super->s_writesize > 1)
-		write_wbuf(sb, area, a + 1);
-
-	*type = JE_AREA;
-	*len = sizeof(*a) + super->s_writesize;
-	return a;
-}
-
-static void *logfs_write_commit(struct super_block *sb, void *h,
-		u16 *type, size_t *len)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	*type = JE_COMMIT;
-	*len = super->s_no_je * sizeof(__be64);
-	return super->s_je_array;
-}
-
-static size_t __logfs_write_je(struct super_block *sb, void *buf, u16 type,
-		size_t len)
-{
-	struct logfs_super *super = logfs_super(sb);
-	void *header = super->s_compressed_je;
-	void *data = header + sizeof(struct logfs_journal_header);
-	ssize_t compr_len, pad_len;
-	u8 compr = COMPR_ZLIB;
-
-	if (len == 0)
-		return logfs_write_header(super, header, 0, type);
-
-	compr_len = logfs_compress(buf, data, len, sb->s_blocksize);
-	if (compr_len < 0 || type == JE_ANCHOR) {
-		memcpy(data, buf, len);
-		compr_len = len;
-		compr = COMPR_NONE;
-	}
-
-	pad_len = ALIGN(compr_len, 16);
-	memset(data + compr_len, 0, pad_len - compr_len);
-
-	return __logfs_write_header(super, header, compr_len, len, type, compr);
-}
-
-static s64 logfs_get_free_bytes(struct logfs_area *area, size_t *bytes,
-		int must_pad)
-{
-	u32 writesize = logfs_super(area->a_sb)->s_writesize;
-	s32 ofs;
-	int ret;
-
-	ret = logfs_open_area(area, *bytes);
-	if (ret)
-		return -EAGAIN;
-
-	ofs = area->a_used_bytes;
-	area->a_used_bytes += *bytes;
-
-	if (must_pad) {
-		area->a_used_bytes = ALIGN(area->a_used_bytes, writesize);
-		*bytes = area->a_used_bytes - ofs;
-	}
-
-	return dev_ofs(area->a_sb, area->a_segno, ofs);
-}
-
-static int logfs_write_je_buf(struct super_block *sb, void *buf, u16 type,
-		size_t buf_len)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_area *area = super->s_journal_area;
-	struct logfs_journal_header *jh = super->s_compressed_je;
-	size_t len;
-	int must_pad = 0;
-	s64 ofs;
-
-	len = __logfs_write_je(sb, buf, type, buf_len);
-	if (jh->h_type == cpu_to_be16(JE_COMMIT))
-		must_pad = 1;
-
-	ofs = logfs_get_free_bytes(area, &len, must_pad);
-	if (ofs < 0)
-		return ofs;
-	logfs_buf_write(area, ofs, super->s_compressed_je, len);
-	BUG_ON(super->s_no_je >= MAX_JOURNAL_ENTRIES);
-	super->s_je_array[super->s_no_je++] = cpu_to_be64(ofs);
-	return 0;
-}
-
-static int logfs_write_je(struct super_block *sb,
-		void* (*write)(struct super_block *sb, void *scratch,
-			u16 *type, size_t *len))
-{
-	void *buf;
-	size_t len;
-	u16 type;
-
-	buf = write(sb, logfs_super(sb)->s_je, &type, &len);
-	return logfs_write_je_buf(sb, buf, type, len);
-}
-
-int write_alias_journal(struct super_block *sb, u64 ino, u64 bix,
-		level_t level, int child_no, __be64 val)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_obj_alias *oa = super->s_je;
-	int err = 0, fill = super->s_je_fill;
-
-	log_aliases("logfs_write_obj_aliases #%x(%llx, %llx, %x, %x) %llx\n",
-			fill, ino, bix, level, child_no, be64_to_cpu(val));
-	oa[fill].ino = cpu_to_be64(ino);
-	oa[fill].bix = cpu_to_be64(bix);
-	oa[fill].val = val;
-	oa[fill].level = (__force u8)level;
-	oa[fill].child_no = cpu_to_be16(child_no);
-	fill++;
-	if (fill >= sb->s_blocksize / sizeof(*oa)) {
-		err = logfs_write_je_buf(sb, oa, JE_OBJ_ALIAS, sb->s_blocksize);
-		fill = 0;
-	}
-
-	super->s_je_fill = fill;
-	return err;
-}
-
-static int logfs_write_obj_aliases(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int err;
-
-	log_journal("logfs_write_obj_aliases: %d aliases to write\n",
-			super->s_no_object_aliases);
-	super->s_je_fill = 0;
-	err = logfs_write_obj_aliases_pagecache(sb);
-	if (err)
-		return err;
-
-	if (super->s_je_fill)
-		err = logfs_write_je_buf(sb, super->s_je, JE_OBJ_ALIAS,
-				super->s_je_fill
-				* sizeof(struct logfs_obj_alias));
-	return err;
-}
-
-/*
- * Write all journal entries.  The goto logic ensures that all journal entries
- * are written whenever a new segment is used.  It is ugly and potentially a
- * bit wasteful, but robustness is more important.  With this we can *always*
- * erase all journal segments except the one containing the most recent commit.
- */
-void logfs_write_anchor(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_area *area = super->s_journal_area;
-	int i, err;
-
-	if (!(super->s_flags & LOGFS_SB_FLAG_DIRTY))
-		return;
-	super->s_flags &= ~LOGFS_SB_FLAG_DIRTY;
-
-	BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);
-	mutex_lock(&super->s_journal_mutex);
-
-	/* Do this first or suffer corruption */
-	logfs_sync_segments(sb);
-	account_shadows(sb);
-
-again:
-	super->s_no_je = 0;
-	for_each_area(i) {
-		if (!super->s_area[i]->a_is_open)
-			continue;
-		super->s_sum_index = i;
-		err = logfs_write_je(sb, logfs_write_area);
-		if (err)
-			goto again;
-	}
-	err = logfs_write_obj_aliases(sb);
-	if (err)
-		goto again;
-	err = logfs_write_je(sb, logfs_write_erasecount);
-	if (err)
-		goto again;
-	err = logfs_write_je(sb, __logfs_write_anchor);
-	if (err)
-		goto again;
-	err = logfs_write_je(sb, logfs_write_dynsb);
-	if (err)
-		goto again;
-	/*
-	 * Order is imperative.  First we sync all writes, including the
-	 * non-committed journal writes.  Then we write the final commit and
-	 * sync the current journal segment.
-	 * There is a theoretical bug here.  Syncing the journal segment will
-	 * write a number of journal entries and the final commit.  All these
-	 * are written in a single operation.  If the device layer writes the
-	 * data back-to-front, the commit will precede the other journal
-	 * entries, leaving a race window.
-	 * Two fixes are possible.  Preferred is to fix the device layer to
-	 * ensure writes happen front-to-back.  Alternatively we can insert
-	 * another logfs_sync_area() super->s_devops->sync() combo before
-	 * writing the commit.
-	 */
-	/*
-	 * On another subject, super->s_devops->sync is usually not necessary.
-	 * Unless called from sys_sync or friends, a barrier would suffice.
-	 */
-	super->s_devops->sync(sb);
-	err = logfs_write_je(sb, logfs_write_commit);
-	if (err)
-		goto again;
-	log_journal("Write commit to %llx\n",
-			be64_to_cpu(super->s_je_array[super->s_no_je - 1]));
-	logfs_sync_area(area);
-	BUG_ON(area->a_used_bytes != area->a_written_bytes);
-	super->s_devops->sync(sb);
-
-	mutex_unlock(&super->s_journal_mutex);
-	return;
-}
-
-void do_logfs_journal_wl_pass(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_area *area = super->s_journal_area;
-	struct btree_head32 *head = &super->s_reserved_segments;
-	u32 segno, ec;
-	int i, err;
-
-	log_journal("Journal requires wear-leveling.\n");
-	/* Drop old segments */
-	journal_for_each(i)
-		if (super->s_journal_seg[i]) {
-			btree_remove32(head, super->s_journal_seg[i]);
-			logfs_set_segment_unreserved(sb,
-					super->s_journal_seg[i],
-					super->s_journal_ec[i]);
-			super->s_journal_seg[i] = 0;
-			super->s_journal_ec[i] = 0;
-		}
-	/* Get new segments */
-	for (i = 0; i < super->s_no_journal_segs; i++) {
-		segno = get_best_cand(sb, &super->s_reserve_list, &ec);
-		super->s_journal_seg[i] = segno;
-		super->s_journal_ec[i] = ec;
-		logfs_set_segment_reserved(sb, segno);
-		err = btree_insert32(head, segno, (void *)1, GFP_NOFS);
-		BUG_ON(err); /* mempool should prevent this */
-		err = logfs_erase_segment(sb, segno, 1);
-		BUG_ON(err); /* FIXME: remount-ro would be nicer */
-	}
-	/* Manually move journal_area */
-	freeseg(sb, area->a_segno);
-	area->a_segno = super->s_journal_seg[0];
-	area->a_is_open = 0;
-	area->a_used_bytes = 0;
-	/* Write journal */
-	logfs_write_anchor(sb);
-	/* Write superblocks */
-	err = logfs_write_sb(sb);
-	BUG_ON(err);
-}
-
-static const struct logfs_area_ops journal_area_ops = {
-	.get_free_segment	= journal_get_free_segment,
-	.get_erase_count	= journal_get_erase_count,
-	.erase_segment		= journal_erase_segment,
-};
-
-int logfs_init_journal(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	size_t bufsize = max_t(size_t, sb->s_blocksize, super->s_writesize)
-		+ MAX_JOURNAL_HEADER;
-	int ret = -ENOMEM;
-
-	mutex_init(&super->s_journal_mutex);
-	btree_init_mempool32(&super->s_reserved_segments, super->s_btree_pool);
-
-	super->s_je = kzalloc(bufsize, GFP_KERNEL);
-	if (!super->s_je)
-		return ret;
-
-	super->s_compressed_je = kzalloc(bufsize, GFP_KERNEL);
-	if (!super->s_compressed_je)
-		return ret;
-
-	super->s_master_inode = logfs_new_meta_inode(sb, LOGFS_INO_MASTER);
-	if (IS_ERR(super->s_master_inode))
-		return PTR_ERR(super->s_master_inode);
-
-	ret = logfs_read_journal(sb);
-	if (ret)
-		return -EIO;
-
-	reserve_sb_and_journal(sb);
-	logfs_calc_free(sb);
-
-	super->s_journal_area->a_ops = &journal_area_ops;
-	return 0;
-}
-
-void logfs_cleanup_journal(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	btree_grim_visitor32(&super->s_reserved_segments, 0, NULL);
-
-	kfree(super->s_compressed_je);
-	kfree(super->s_je);
-}

fs/logfs/logfs.h

···
-/*
- * fs/logfs/logfs.h
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- *
- * Private header for logfs.
- */
-#ifndef FS_LOGFS_LOGFS_H
-#define FS_LOGFS_LOGFS_H
-
-#include <linux/types.h>
-#include <linux/btree.h>
-#include <linux/crc32.h>
-#include <linux/fs.h>
-#include <linux/kernel.h>
-#include <linux/mempool.h>
-#include <linux/pagemap.h>
-#include <linux/mtd/mtd.h>
-#include "logfs_abi.h"
-
-#define LOGFS_DEBUG_SUPER	(0x0001)
-#define LOGFS_DEBUG_SEGMENT	(0x0002)
-#define LOGFS_DEBUG_JOURNAL	(0x0004)
-#define LOGFS_DEBUG_DIR		(0x0008)
-#define LOGFS_DEBUG_FILE	(0x0010)
-#define LOGFS_DEBUG_INODE	(0x0020)
-#define LOGFS_DEBUG_READWRITE	(0x0040)
-#define LOGFS_DEBUG_GC		(0x0080)
-#define LOGFS_DEBUG_GC_NOISY	(0x0100)
-#define LOGFS_DEBUG_ALIASES	(0x0200)
-#define LOGFS_DEBUG_BLOCKMOVE	(0x0400)
-#define LOGFS_DEBUG_ALL		(0xffffffff)
-
-#define LOGFS_DEBUG		(0x01)
-/*
- * To enable specific log messages, simply define LOGFS_DEBUG to match any
- * or all of the above.
- */
-#ifndef LOGFS_DEBUG
-#define LOGFS_DEBUG		(0)
-#endif
-
-#define log_cond(cond, fmt, arg...) do {	\
-	if (cond)				\
-		printk(KERN_DEBUG fmt, ##arg);	\
-} while (0)
-
-#define log_super(fmt, arg...) \
-	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_SUPER, fmt, ##arg)
-#define log_segment(fmt, arg...) \
-	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_SEGMENT, fmt, ##arg)
-#define log_journal(fmt, arg...) \
-	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_JOURNAL, fmt, ##arg)
-#define log_dir(fmt, arg...) \
-	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_DIR, fmt, ##arg)
-#define log_file(fmt, arg...) \
-	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_FILE, fmt, ##arg)
-#define log_inode(fmt, arg...) \
-	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_INODE, fmt, ##arg)
-#define log_readwrite(fmt, arg...) \
-	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_READWRITE, fmt, ##arg)
-#define log_gc(fmt, arg...) \
-	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_GC, fmt, ##arg)
-#define log_gc_noisy(fmt, arg...) \
-	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_GC_NOISY, fmt, ##arg)
-#define log_aliases(fmt, arg...) \
-	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_ALIASES, fmt, ##arg)
-#define log_blockmove(fmt, arg...) \
-	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_BLOCKMOVE, fmt, ##arg)
-
-#define PG_pre_locked		PG_owner_priv_1
-#define PagePreLocked(page)	test_bit(PG_pre_locked, &(page)->flags)
-#define SetPagePreLocked(page)	set_bit(PG_pre_locked, &(page)->flags)
-#define ClearPagePreLocked(page) clear_bit(PG_pre_locked, &(page)->flags)
-
-/* FIXME: This should really be somewhere in the 64bit area. */
-#define LOGFS_LINK_MAX		(1<<30)
-
-/* Read-only filesystem */
-#define LOGFS_SB_FLAG_RO	0x0001
-#define LOGFS_SB_FLAG_DIRTY	0x0002
-#define LOGFS_SB_FLAG_OBJ_ALIAS	0x0004
-#define LOGFS_SB_FLAG_SHUTDOWN	0x0008
-
-/* Write Control Flags */
-#define WF_LOCK			0x01 /* take write lock */
-#define WF_WRITE		0x02 /* write block */
-#define WF_DELETE		0x04 /* delete old block */
-
-typedef u8 __bitwise level_t;
-typedef u8 __bitwise gc_level_t;
-
-#define LEVEL(level) ((__force level_t)(level))
-#define GC_LEVEL(gc_level) ((__force gc_level_t)(gc_level))
-
-#define SUBLEVEL(level) ( (void)((level) == LEVEL(1)),	\
-		(__force level_t)((__force u8)(level) - 1) )
-
-/**
- * struct logfs_area - area management information
- *
- * @a_sb:			the superblock this area belongs to
- * @a_is_open:			1 if the area is currently open, else 0
- * @a_segno:			segment number of area
- * @a_written_bytes:		number of bytes already written back
- * @a_used_bytes:		number of used bytes
- * @a_ops:			area operations (either journal or ostore)
- * @a_erase_count:		erase count
- * @a_level:			GC level
- */
-struct logfs_area { /* a segment open for writing */
-	struct super_block *a_sb;
-	int	a_is_open;
-	u32	a_segno;
-	u32	a_written_bytes;
-	u32	a_used_bytes;
-	const struct logfs_area_ops *a_ops;
-	u32	a_erase_count;
-	gc_level_t a_level;
-};
-
-/**
- * struct logfs_area_ops - area operations
- *
- * @get_free_segment:		fill area->ofs with the offset of a free segment
- * @get_erase_count:		fill area->erase_count (needs area->ofs)
- * @erase_segment:		erase and setup segment
- */
-struct logfs_area_ops {
-	void	(*get_free_segment)(struct logfs_area *area);
-	void	(*get_erase_count)(struct logfs_area *area);
-	int	(*erase_segment)(struct logfs_area *area);
-};
-
-struct logfs_super;	/* forward */
-/**
- * struct logfs_device_ops - device access operations
- *
- * @readpage:			read one page (mm page)
- * @writeseg:			write one segment.  may be a partial segment
- * @erase:			erase one segment
- * @read:			read from the device
- * @erase:			erase part of the device
- * @can_write_buf:		decide whether wbuf can be written to ofs
- */
-struct logfs_device_ops {
-	struct page *(*find_first_sb)(struct super_block *sb, u64 *ofs);
-	struct page *(*find_last_sb)(struct super_block *sb, u64 *ofs);
-	int (*write_sb)(struct super_block *sb, struct page *page);
-	int (*readpage)(void *_sb, struct page *page);
-	void (*writeseg)(struct super_block *sb, u64 ofs, size_t len);
-	int (*erase)(struct super_block *sb, loff_t ofs, size_t len,
-			int ensure_write);
-	int (*can_write_buf)(struct super_block *sb, u64 ofs);
-	void (*sync)(struct super_block *sb);
-	void (*put_device)(struct logfs_super *s);
-};
-
-/**
- * struct candidate_list - list of similar candidates
- */
-struct candidate_list {
-	struct rb_root rb_tree;
-	int count;
-	int maxcount;
-	int sort_by_ec;
-};
-
-/**
- * struct gc_candidate - "candidate" segment to be garbage collected next
- *
- * @list:			list (either free of low)
- * @segno:			segment number
- * @valid:			number of valid bytes
- * @erase_count:		erase count of segment
- * @dist:			distance from tree root
- *
- * Candidates can be on two lists.  The free list contains electees rather
- * than candidates - segments that no longer contain any valid data.  The
- * low list contains candidates to be picked for GC.  It should be kept
- * short.  It is not required to always pick a perfect candidate.  In the
- * worst case GC will have to move more data than absolutely necessary.
- */
-struct gc_candidate {
-	struct rb_node rb_node;
-	struct candidate_list *list;
-	u32	segno;
-	u32	valid;
-	u32	erase_count;
-	u8	dist;
-};
-
-/**
- * struct logfs_journal_entry - temporary structure used during journal scan
- *
- * @used:
- * @version:			normalized version
- * @len:			length
- * @offset:			offset
- */
-struct logfs_journal_entry {
-	int used;
-	s16 version;
-	u16 len;
-	u16 datalen;
-	u64 offset;
-};
-
-enum transaction_state {
-	CREATE_1 = 1,
-	CREATE_2,
-	UNLINK_1,
-	UNLINK_2,
-	CROSS_RENAME_1,
-	CROSS_RENAME_2,
-	TARGET_RENAME_1,
-	TARGET_RENAME_2,
-	TARGET_RENAME_3
-};
-
-/**
- * struct logfs_transaction - essential fields to support atomic dirops
- *
- * @ino:			target inode
- * @dir:			inode of directory containing dentry
- * @pos:			pos of dentry in directory
- */
-struct logfs_transaction {
-	enum transaction_state state;
-	u64	 ino;
-	u64	 dir;
-	u64	 pos;
-};
-
-/**
- * struct logfs_shadow - old block in the shadow of a not-yet-committed new one
- * @old_ofs:			offset of old block on medium
- * @new_ofs:			offset of new block on medium
- * @ino:			inode number
- * @bix:			block index
- * @old_len:			size of old block, including header
- * @new_len:			size of new block, including header
- * @level:			block level
- */
-struct logfs_shadow {
-	u64 old_ofs;
-	u64 new_ofs;
-	u64 ino;
-	u64 bix;
-	int old_len;
-	int new_len;
-	gc_level_t gc_level;
-};
-
-/**
- * struct shadow_tree
- * @new:			shadows where old_ofs==0, indexed by new_ofs
- * @old:			shadows where old_ofs!=0, indexed by old_ofs
- * @segment_map:		bitfield of segments containing shadows
- * @no_shadowed_segment:	number of segments containing shadows
- */
-struct shadow_tree {
-	struct btree_head64 new;
-	struct btree_head64 old;
-	struct btree_head32 segment_map;
-	int no_shadowed_segments;
-};
-
-struct object_alias_item {
-	struct list_head list;
-	__be64 val;
-	int child_no;
-};
-
-/**
- * struct logfs_block - contains any block state
- * @type:			indirect block or inode
- * @full:			number of fully populated children
- * @partial:			number of partially populated children
- *
- * Most blocks are directly represented by page cache pages.  But when a block
- * becomes dirty, is part of a transaction, contains aliases or is otherwise
- * special, a struct logfs_block is allocated to track the additional state.
- * Inodes are very similar to indirect blocks, so they can also get one of
- * these structures added when appropriate.
- */
-#define BLOCK_INDIRECT	1	/* Indirect block */
-#define BLOCK_INODE	2	/* Inode */
-struct logfs_block_ops;
-struct logfs_block {
-	struct list_head alias_list;
-	struct list_head item_list;
-	struct super_block *sb;
-	u64 ino;
-	u64 bix;
-	level_t level;
-	struct page *page;
-	struct inode *inode;
-	struct logfs_transaction *ta;
-	unsigned long alias_map[LOGFS_BLOCK_FACTOR / BITS_PER_LONG];
-	const struct logfs_block_ops *ops;
-	int full;
-	int partial;
-	int reserved_bytes;
-};
-
-typedef int write_alias_t(struct super_block *sb, u64 ino, u64 bix,
-		level_t level, int child_no, __be64 val);
-struct logfs_block_ops {
-	void	(*write_block)(struct logfs_block *block);
-	void	(*free_block)(struct super_block *sb, struct logfs_block*block);
-	int	(*write_alias)(struct super_block *sb,
-			struct logfs_block *block,
-			write_alias_t *write_one_alias);
-};
-
-#define MAX_JOURNAL_ENTRIES 256
-
-struct logfs_super {
-	struct mtd_info *s_mtd;			/* underlying device */
-	struct block_device *s_bdev;		/* underlying device */
-	const struct logfs_device_ops *s_devops;/* device access */
-	struct inode	*s_master_inode;	/* inode file */
-	struct inode	*s_segfile_inode;	/* segment file */
-	struct inode *s_mapping_inode;		/* device mapping */
-	atomic_t s_pending_writes;		/* outstanting bios */
-	long	 s_flags;
-	mempool_t *s_btree_pool;		/* for btree nodes */
-	mempool_t *s_alias_pool;		/* aliases in segment.c */
-	u64	 s_feature_incompat;
-	u64	 s_feature_ro_compat;
-	u64	 s_feature_compat;
-	u64	 s_feature_flags;
-	u64	 s_sb_ofs[2];
-	struct page *s_erase_page;		/* for dev_bdev.c */
-	/* alias.c fields */
-	struct btree_head32 s_segment_alias;	/* remapped segments */
-	int	 s_no_object_aliases;
-	struct list_head s_object_alias;	/* remapped objects */
-	struct btree_head128 s_object_alias_tree; /* remapped objects */
-	struct mutex s_object_alias_mutex;
-	/* dir.c fields */
-	struct mutex s_dirop_mutex;		/* for creat/unlink/rename */
-	u64	 s_victim_ino;			/* used for atomic dir-ops */
-	u64	 s_rename_dir;			/* source directory ino */
-	u64	 s_rename_pos;			/* position of source dd */
-	/* gc.c fields */
-	long	 s_segsize;			/* size of a segment */
-	int	 s_segshift;			/* log2 of segment size */
-	long	 s_segmask;			/* 1 << s_segshift - 1 */
-	long	 s_no_segs;			/* segments on device */
-	long	 s_no_journal_segs;		/* segments used for journal */
-	long	 s_no_blocks;			/* blocks per segment */
-	long	 s_writesize;			/* minimum write size */
-	int	 s_writeshift;			/* log2 of write size */
-	u64	 s_size;			/* filesystem size */
-	struct logfs_area *s_area[LOGFS_NO_AREAS];	/* open segment array */
-	u64	 s_gec;				/* global erase count */
-	u64	 s_wl_gec_ostore;		/* time of last wl event */
-	u64	 s_wl_gec_journal;		/* time of last wl event */
-	u64	 s_sweeper;			/* current sweeper pos */
-	u8	 s_ifile_levels;		/* max level of ifile */
-	u8	 s_iblock_levels;		/* max level of regular files */
-	u8	 s_data_levels;			/* # of segments to leaf block*/
-	u8	 s_total_levels;		/* sum of above three */
-	struct btree_head32 s_cand_tree;	/* all candidates */
-	struct candidate_list s_free_list;	/* 100% free segments */
-	struct candidate_list s_reserve_list;	/* Bad segment reserve */
-	struct candidate_list s_low_list[LOGFS_NO_AREAS];/* good candidates */
-	struct candidate_list s_ec_list;	/* wear level candidates */
-	struct btree_head32 s_reserved_segments;/* sb, journal, bad, etc. */
-	/* inode.c fields */
-	u64	 s_last_ino;			/* highest ino used */
-	long	 s_inos_till_wrap;
-	u32	 s_generation;			/* i_generation for new files */
-	struct list_head s_freeing_list;	/* inodes being freed */
-	/* journal.c fields */
-	struct mutex s_journal_mutex;
-	void	*s_je;				/* journal entry to compress */
-	void	*s_compressed_je;		/* block to write to journal */
-	u32	 s_journal_seg[LOGFS_JOURNAL_SEGS]; /* journal segments */
-	u32	 s_journal_ec[LOGFS_JOURNAL_SEGS]; /* journal erasecounts */
-	u64	 s_last_version;
-	struct logfs_area *s_journal_area;	/* open journal segment */
-	__be64	s_je_array[MAX_JOURNAL_ENTRIES];
-	int	s_no_je;
-
-	int	 s_sum_index;			/* for the 12 summaries */
-	struct shadow_tree s_shadow_tree;
-	int	 s_je_fill;			/* index of current je */
-	/* readwrite.c fields */
-	struct mutex s_write_mutex;
-	int	 s_lock_count;
-	mempool_t *s_block_pool;		/* struct logfs_block pool */
-	mempool_t *s_shadow_pool;		/* struct logfs_shadow pool */
-	struct list_head s_writeback_list;	/* writeback pages */
-	/*
-	 * Space accounting:
-	 * - s_used_bytes specifies space used to store valid data objects.
-	 * - s_dirty_used_bytes is space used to store non-committed data
-	 *   objects.  Those objects have already been written themselves,
-	 *   but they don't become valid until all indirect blocks up to the
-	 *   journal have been written as well.
-	 * - s_dirty_free_bytes is space used to store the old copy of a
-	 *   replaced object, as long as the replacement is non-committed.
-	 *   In other words, it is the amount of space freed when all dirty
-	 *   blocks are written back.
-	 * - s_free_bytes is the amount of free space available for any
-	 *   purpose.
-	 * - s_root_reserve is the amount of free space available only to
-	 *   the root user.  Non-privileged users can no longer write once
-	 *   this watermark has been reached.
-	 * - s_speed_reserve is space which remains unused to speed up
-	 *   garbage collection performance.
-	 * - s_dirty_pages is the space reserved for currently dirty pages.
-	 *   It is a pessimistic estimate, so some/most will get freed on
-	 *   page writeback.
-	 *
-	 * s_used_bytes + s_free_bytes + s_speed_reserve = total usable size
-	 */
-	u64	 s_free_bytes;
-	u64	 s_used_bytes;
-	u64	 s_dirty_free_bytes;
-	u64	 s_dirty_used_bytes;
-	u64	 s_root_reserve;
-	u64	 s_speed_reserve;
-	u64	 s_dirty_pages;
-	/* Bad block handling:
-	 * - s_bad_seg_reserve is a number of segments usually kept
-	 *   free.  When encountering bad blocks, the affected segment's data
-	 *   is _temporarily_ moved to a reserved segment.
-	 * - s_bad_segments is the number of known bad segments.
-	 */
-	u32	 s_bad_seg_reserve;
-	u32	 s_bad_segments;
-};
-
-/**
- * struct logfs_inode - in-memory inode
- *
- * @vfs_inode:			struct inode
- * @li_data:			data pointers
- * @li_used_bytes:		number of used bytes
- * @li_freeing_list:		used to track inodes currently being freed
- * @li_flags:			inode flags
- * @li_refcount:		number of internal (GC-induced) references
- */
-struct logfs_inode {
-	struct inode vfs_inode;
-	u64	li_data[LOGFS_EMBEDDED_FIELDS];
-	u64	li_used_bytes;
-	struct list_head li_freeing_list;
-	struct logfs_block *li_block;
-	u32	li_flags;
-	u8	li_height;
-	int	li_refcount;
-};
-
-#define journal_for_each(__i) for (__i = 0; __i < LOGFS_JOURNAL_SEGS; __i++)
-#define for_each_area(__i) for (__i = 0; __i < LOGFS_NO_AREAS; __i++)
-#define for_each_area_down(__i) for (__i = LOGFS_NO_AREAS - 1; __i >= 0; __i--)
-
-/* compr.c */
-int logfs_compress(void *in, void *out, size_t inlen, size_t outlen);
-int logfs_uncompress(void *in, void *out, size_t inlen, size_t outlen);
-int __init logfs_compr_init(void);
-void logfs_compr_exit(void);
-
-/* dev_bdev.c */
-#ifdef CONFIG_BLOCK
-int logfs_get_sb_bdev(struct logfs_super *s,
-		struct file_system_type *type,
-		const char *devname);
-#else
-static inline int logfs_get_sb_bdev(struct logfs_super *s,
-		struct file_system_type *type,
-		const char *devname)
-{
-	return -ENODEV;
-}
-#endif
-
-/* dev_mtd.c */
-#if IS_ENABLED(CONFIG_MTD)
-int logfs_get_sb_mtd(struct logfs_super *s, int mtdnr);
-#else
-static inline int logfs_get_sb_mtd(struct logfs_super *s, int mtdnr)
-{
-	return -ENODEV;
-}
-#endif
-
-/* dir.c */
-extern const struct inode_operations logfs_dir_iops;
-extern const struct file_operations logfs_dir_fops;
-int logfs_replay_journal(struct super_block *sb);
-
-/* file.c */
-extern const struct inode_operations logfs_reg_iops;
-extern const struct file_operations logfs_reg_fops;
-extern const struct address_space_operations logfs_reg_aops;
-int logfs_readpage(struct file *file, struct page *page);
-long logfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
-int logfs_fsync(struct file *file, loff_t start, loff_t end, int datasync);
-
-/* gc.c */
-u32 get_best_cand(struct super_block *sb, struct candidate_list *list, u32 *ec);
-void logfs_gc_pass(struct super_block *sb);
-int logfs_check_areas(struct super_block *sb);
-int logfs_init_gc(struct super_block *sb);
-void logfs_cleanup_gc(struct super_block *sb);
-
-/* inode.c */
-extern const struct super_operations logfs_super_operations;
-struct inode *logfs_iget(struct super_block *sb, ino_t ino);
-struct inode *logfs_safe_iget(struct super_block *sb, ino_t ino, int *cookie);
-void logfs_safe_iput(struct inode *inode, int cookie);
-struct inode *logfs_new_inode(struct inode *dir, umode_t mode);
-struct inode *logfs_new_meta_inode(struct super_block *sb, u64 ino);
-struct inode *logfs_read_meta_inode(struct super_block *sb, u64 ino);
-int logfs_init_inode_cache(void);
-void logfs_destroy_inode_cache(void);
-void logfs_set_blocks(struct inode *inode, u64 no);
-/* these logically belong into inode.c but actually reside in readwrite.c */
-int logfs_read_inode(struct inode *inode);
-int __logfs_write_inode(struct inode *inode, struct page *, long flags);
-void logfs_evict_inode(struct inode *inode);
-
-/* journal.c */
-void logfs_write_anchor(struct super_block *sb);
-int logfs_init_journal(struct super_block *sb);
-void logfs_cleanup_journal(struct super_block *sb);
-int write_alias_journal(struct super_block *sb, u64 ino, u64 bix,
-		level_t level, int child_no, __be64 val);
-void do_logfs_journal_wl_pass(struct super_block *sb);
-
-/* readwrite.c */
-pgoff_t logfs_pack_index(u64 bix, level_t level);
-void logfs_unpack_index(pgoff_t index, u64 *bix, level_t *level);
-int logfs_inode_write(struct inode *inode, const void *buf, size_t count,
-		loff_t bix, long flags, struct shadow_tree *shadow_tree);
-int logfs_readpage_nolock(struct page *page);
-int logfs_write_buf(struct inode *inode, struct page *page, long flags);
-int logfs_delete(struct inode *inode, pgoff_t index,
-		struct shadow_tree *shadow_tree);
-int logfs_rewrite_block(struct inode *inode, u64 bix, u64 ofs,
-		gc_level_t gc_level, long flags);
-int logfs_is_valid_block(struct super_block *sb, u64 ofs, u64 ino, u64 bix,
-		gc_level_t gc_level);
-int logfs_truncate(struct inode *inode, u64 size);
-u64 logfs_seek_hole(struct inode *inode, u64 bix);
-u64 logfs_seek_data(struct inode *inode, u64 bix);
-int logfs_open_segfile(struct super_block *sb);
-int logfs_init_rw(struct super_block *sb);
-void logfs_cleanup_rw(struct super_block *sb);
-void logfs_add_transaction(struct inode *inode, struct logfs_transaction *ta);
-void logfs_del_transaction(struct inode *inode, struct logfs_transaction *ta);
-void logfs_write_block(struct logfs_block *block, long flags);
-int logfs_write_obj_aliases_pagecache(struct super_block *sb);
-void logfs_get_segment_entry(struct super_block *sb, u32 segno,
-		struct logfs_segment_entry *se);
-void logfs_set_segment_used(struct super_block *sb, u64 ofs, int increment);
-void logfs_set_segment_erased(struct super_block *sb, u32 segno, u32 ec,
-		gc_level_t gc_level);
-void logfs_set_segment_reserved(struct super_block *sb, u32 segno);
-void logfs_set_segment_unreserved(struct super_block *sb, u32 segno, u32 ec);
-struct logfs_block *__alloc_block(struct super_block *sb,
-		u64 ino, u64 bix, level_t level);
-void __free_block(struct super_block *sb, struct logfs_block *block);
-void btree_write_block(struct logfs_block *block);
-void initialize_block_counters(struct page *page, struct logfs_block *block,
-		__be64 *array, int page_is_empty);
-int logfs_exist_block(struct inode *inode, u64 bix);
-int get_page_reserve(struct inode *inode, struct page *page);
-void logfs_get_wblocks(struct super_block *sb, struct page *page, int lock);
-void logfs_put_wblocks(struct super_block *sb, struct page *page, int lock);
-extern const struct logfs_block_ops indirect_block_ops;
-
-/* segment.c */
-int logfs_erase_segment(struct super_block *sb, u32 ofs, int ensure_erase);
-int wbuf_read(struct super_block *sb, u64 ofs, size_t len, void *buf);
-int logfs_segment_read(struct inode *inode, struct page *page, u64 ofs, u64 bix,
-		level_t level);
-int logfs_segment_write(struct inode *inode, struct page *page,
-		struct logfs_shadow *shadow);
-int logfs_segment_delete(struct inode *inode, struct logfs_shadow *shadow);
-int logfs_load_object_aliases(struct super_block *sb,
-		struct logfs_obj_alias *oa, int count);
-void move_page_to_btree(struct page *page);
-int logfs_init_mapping(struct super_block *sb);
-void logfs_sync_area(struct logfs_area *area);
-void logfs_sync_segments(struct super_block *sb);
-void freeseg(struct super_block *sb, u32 segno);
-void free_areas(struct super_block *sb);
-
-/* area handling */
-int logfs_init_areas(struct super_block *sb);
-void logfs_cleanup_areas(struct super_block *sb);
-int logfs_open_area(struct logfs_area *area, size_t bytes);
-int __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
-		int use_filler);
-
-static inline int logfs_buf_write(struct logfs_area *area, u64 ofs,
-		void *buf, size_t len)
-{
-	return __logfs_buf_write(area, ofs, buf, len, 0);
-}
-
-static inline int logfs_buf_recover(struct logfs_area *area, u64 ofs,
-		void *buf, size_t len)
-{
-	return __logfs_buf_write(area, ofs, buf, len, 1);
-}
-
-/* super.c */
-struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index);
-void emergency_read_end(struct page *page);
-void logfs_crash_dump(struct super_block *sb);
-int logfs_statfs(struct dentry *dentry, struct kstatfs *stats);
-int logfs_check_ds(struct logfs_disk_super *ds);
-int logfs_write_sb(struct super_block *sb);
-
-static inline struct logfs_super *logfs_super(struct super_block *sb)
-{
-	return sb->s_fs_info;
-}
-
-static inline struct logfs_inode *logfs_inode(struct inode *inode)
-{
-	return container_of(inode, struct logfs_inode, vfs_inode);
-}
-
-static inline void logfs_set_ro(struct super_block *sb)
-{
-	logfs_super(sb)->s_flags |= LOGFS_SB_FLAG_RO;
-}
-
-#define LOGFS_BUG(sb) do {					\
-	struct super_block *__sb = sb;				\
-	logfs_crash_dump(__sb);					\
-	logfs_super(__sb)->s_flags |= LOGFS_SB_FLAG_RO;		\
-	BUG();							\
-} while (0)
-
-#define LOGFS_BUG_ON(condition, sb) \
-	do { if (unlikely(condition)) LOGFS_BUG((sb)); } while (0)
-
-static inline __be32 logfs_crc32(void *data, size_t len, size_t skip)
-{
-	return cpu_to_be32(crc32(~0, data+skip, len-skip));
-}
-
-static inline u8 logfs_type(struct inode *inode)
-{
-	return (inode->i_mode >> 12) & 15;
-}
-
-static inline pgoff_t logfs_index(struct super_block *sb, u64 pos)
-{
-	return pos >> sb->s_blocksize_bits;
-}
-
-static inline u64 dev_ofs(struct super_block *sb, u32 segno, u32 ofs)
-{
-	return ((u64)segno << logfs_super(sb)->s_segshift) + ofs;
-}
-
-static inline u32 seg_no(struct super_block *sb, u64 ofs)
-{
-	return ofs >> logfs_super(sb)->s_segshift;
-}
-
-static inline u32 seg_ofs(struct super_block *sb, u64 ofs)
-{
-	return ofs & logfs_super(sb)->s_segmask;
-}
-
-static inline u64 seg_align(struct super_block *sb, u64 ofs)
-{
-	return ofs & ~logfs_super(sb)->s_segmask;
-}
-
-static inline struct logfs_block *logfs_block(struct page *page)
-{
-	return (void *)page->private;
-}
-
-static inline level_t shrink_level(gc_level_t __level)
-{
-	u8 level = (__force u8)__level;
-
-	if (level >= LOGFS_MAX_LEVELS)
-		level -= LOGFS_MAX_LEVELS;
-	return (__force level_t)level;
-}
-
-static inline gc_level_t expand_level(u64 ino, level_t __level)
-{
-	u8 level = (__force u8)__level;
-
-	if (ino == LOGFS_INO_MASTER) {
-		/* ifile has separate areas */
-		level += LOGFS_MAX_LEVELS;
-	}
-	return (__force gc_level_t)level;
-}
-
-static inline int logfs_block_shift(struct super_block *sb, level_t level)
-{
-	level = shrink_level((__force gc_level_t)level);
-	return (__force int)level * (sb->s_blocksize_bits - 3);
-}
-
-static inline u64 logfs_block_mask(struct super_block *sb, level_t level)
-{
-	return ~0ull << logfs_block_shift(sb, level);
-}
-
-static inline struct logfs_area *get_area(struct super_block *sb,
-		gc_level_t gc_level)
-{
-	return logfs_super(sb)->s_area[(__force u8)gc_level];
-}
-
-static inline void logfs_mempool_destroy(mempool_t *pool)
-{
-	if (pool)
-		mempool_destroy(pool);
-}
-
-#endif

fs/logfs/logfs_abi.h

···
-/*
- * fs/logfs/logfs_abi.h
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- *
- * Public header for logfs.
- */
-#ifndef FS_LOGFS_LOGFS_ABI_H
-#define FS_LOGFS_LOGFS_ABI_H
-
-/* For out-of-kernel compiles */
-#ifndef BUILD_BUG_ON
-#define BUILD_BUG_ON(condition) /**/
-#endif
-
-#define SIZE_CHECK(type, size)					\
-static inline void check_##type(void)				\
-{								\
-	BUILD_BUG_ON(sizeof(struct type) != (size));		\
-}
-
-/*
- * Throughout the logfs code, we're constantly dealing with blocks at
- * various positions or offsets.  To remove confusion, we stricly
- * distinguish between a "position" - the logical position within a
- * file and an "offset" - the physical location within the device.
- *
- * Any usage of the term offset for a logical location or position for
- * a physical one is a bug and should get fixed.
- */
-
-/*
- * Block are allocated in one of several segments depending on their
- * level.  The following levels are used:
- *  0	- regular data block
- *  1	- i1 indirect blocks
- *  2	- i2 indirect blocks
- *  3	- i3 indirect blocks
- *  4	- i4 indirect blocks
- *  5	- i5 indirect blocks
- *  6	- ifile data blocks
- *  7	- ifile i1 indirect blocks
- *  8	- ifile i2 indirect blocks
- *  9	- ifile i3 indirect blocks
- * 10	- ifile i4 indirect blocks
- * 11	- ifile i5 indirect blocks
- * Potential levels to be used in the future:
- * 12	- gc recycled blocks, long-lived data
- * 13	- replacement blocks, short-lived data
- *
- * Levels 1-11 are necessary for robust gc operations and help separate
- * short-lived metadata from longer-lived file data.  In the future,
- * file data should get separated into several segments based on simple
- * heuristics.  Old data recycled during gc operation is expected to be
- * long-lived.  New data is of uncertain life expectancy.  New data
- * used to replace older blocks in existing files is expected to be
- * short-lived.
- */
-
-
-/* Magic numbers.  64bit for superblock, 32bit for statfs f_type */
-#define LOGFS_MAGIC		0x7a3a8e5cb9d5bf67ull
-#define LOGFS_MAGIC_U32		0xc97e8168u
-
-/*
- * Various blocksize related macros.  Blocksize is currently fixed at 4KiB.
- * Sooner or later that should become configurable and the macros replaced
- * by something superblock-dependent.  Pointers in indirect blocks are and
- * will remain 64bit.
- *
- * LOGFS_BLOCKSIZE	- self-explaining
- * LOGFS_BLOCK_FACTOR	- number of pointers per indirect block
- * LOGFS_BLOCK_BITS	- log2 of LOGFS_BLOCK_FACTOR, used for shifts
- */
-#define LOGFS_BLOCKSIZE		(4096ull)
-#define LOGFS_BLOCK_FACTOR	(LOGFS_BLOCKSIZE / sizeof(u64))
-#define LOGFS_BLOCK_BITS	(9)
-
-/*
- * Number of blocks at various levels of indirection.  There are 16 direct
- * block pointers plus a single indirect pointer.
- */
-#define I0_BLOCKS		(16)
-#define I1_BLOCKS		LOGFS_BLOCK_FACTOR
-#define I2_BLOCKS		(LOGFS_BLOCK_FACTOR * I1_BLOCKS)
-#define I3_BLOCKS		(LOGFS_BLOCK_FACTOR * I2_BLOCKS)
-#define I4_BLOCKS		(LOGFS_BLOCK_FACTOR * I3_BLOCKS)
-#define I5_BLOCKS		(LOGFS_BLOCK_FACTOR * I4_BLOCKS)
-
-#define INDIRECT_INDEX		I0_BLOCKS
-#define LOGFS_EMBEDDED_FIELDS	(I0_BLOCKS + 1)
-
-/*
- * Sizes at which files require another level of indirection.  Files smaller
- * than LOGFS_EMBEDDED_SIZE can be completely stored in the inode itself,
- * similar like ext2 fast symlinks.
- *
- * Data at a position smaller than LOGFS_I0_SIZE is accessed through the
- * direct pointers, else through the 1x indirect pointer and so forth.
- */
-#define LOGFS_EMBEDDED_SIZE	(LOGFS_EMBEDDED_FIELDS * sizeof(u64))
-#define LOGFS_I0_SIZE		(I0_BLOCKS * LOGFS_BLOCKSIZE)
-#define LOGFS_I1_SIZE		(I1_BLOCKS * LOGFS_BLOCKSIZE)
-#define LOGFS_I2_SIZE		(I2_BLOCKS * LOGFS_BLOCKSIZE)
-#define LOGFS_I3_SIZE		(I3_BLOCKS * LOGFS_BLOCKSIZE)
-#define LOGFS_I4_SIZE		(I4_BLOCKS * LOGFS_BLOCKSIZE)
-#define LOGFS_I5_SIZE		(I5_BLOCKS * LOGFS_BLOCKSIZE)
-
-/*
- * Each indirect block pointer must have this flag set, if all block pointers
- * behind it are set, i.e. there is no hole hidden in the shadow of this
- * indirect block pointer.
- */
-#define LOGFS_FULLY_POPULATED (1ULL << 63)
-#define pure_ofs(ofs) (ofs & ~LOGFS_FULLY_POPULATED)
-
-/*
- * LogFS needs to separate data into levels.  Each level is defined as the
- * maximal possible distance from the master inode (inode of the inode file).
- * Data blocks reside on level 0, 1x indirect block on level 1, etc.
- * Inodes reside on level 6, indirect blocks for the inode file on levels 7-11.
- * This effort is necessary to guarantee garbage collection to always make
- * progress.
- *
- * LOGFS_MAX_INDIRECT is the maximal indirection through indirect blocks,
- * LOGFS_MAX_LEVELS is one more for the actual data level of a file.  It is
- * the maximal number of levels for one file.
- * LOGFS_NO_AREAS is twice that, as the inode file and regular files are
- * effectively stacked on top of each other.
- */
-#define LOGFS_MAX_INDIRECT	(5)
-#define LOGFS_MAX_LEVELS	(LOGFS_MAX_INDIRECT + 1)
-#define LOGFS_NO_AREAS		(2 * LOGFS_MAX_LEVELS)
-
-/* Maximum size of filenames */
-#define LOGFS_MAX_NAMELEN	(255)
-
-/* Number of segments in the primary journal. */
-#define LOGFS_JOURNAL_SEGS	(16)
-
-/* Maximum number of free/erased/etc. segments in journal entries */
-#define MAX_CACHED_SEGS		(64)
-
-
-/*
- * LOGFS_OBJECT_HEADERSIZE is the size of a single header in the object store,
- * LOGFS_MAX_OBJECTSIZE the size of the largest possible object, including
- * its header,
- * LOGFS_SEGMENT_RESERVE is the amount of space reserved for each segment for
- * its segment header and the padded space at the end when no further objects
- * fit.
- */
-#define LOGFS_OBJECT_HEADERSIZE	(0x1c)
-#define LOGFS_SEGMENT_HEADERSIZE (0x18)
-#define LOGFS_MAX_OBJECTSIZE	(LOGFS_OBJECT_HEADERSIZE + LOGFS_BLOCKSIZE)
-#define LOGFS_SEGMENT_RESERVE	\
-	(LOGFS_SEGMENT_HEADERSIZE + LOGFS_MAX_OBJECTSIZE - 1)
-
-/*
- * Segment types:
- * SEG_SUPER	- Data or indirect block
- * SEG_JOURNAL	- Inode
- * SEG_OSTORE	- Dentry
- */
-enum {
-	SEG_SUPER	= 0x01,
-	SEG_JOURNAL	= 0x02,
-	SEG_OSTORE	= 0x03,
-};
-
-/**
- * struct logfs_segment_header - per-segment header in the ostore
- *
- * @crc:			crc32 of header (there is no data)
- * @pad:			unused, must be 0
- * @type:			segment type, see above
- * @level:			GC level for all objects in this segment
- * @segno:			segment number
- * @ec:				erase count for this segment
- * @gec:			global erase count at time of writing
- */
-struct logfs_segment_header {
-	__be32	crc;
-	__be16	pad;
-	__u8	type;
-	__u8	level;
-	__be32	segno;
-	__be32	ec;
-	__be64	gec;
-};
-
-SIZE_CHECK(logfs_segment_header, LOGFS_SEGMENT_HEADERSIZE);
-
-#define LOGFS_FEATURES_INCOMPAT		(0ull)
-#define LOGFS_FEATURES_RO_COMPAT	(0ull)
-#define LOGFS_FEATURES_COMPAT		(0ull)
-
-/**
- * struct logfs_disk_super - on-medium superblock
- *
- * @ds_magic:			magic number, must equal LOGFS_MAGIC
- * @ds_crc:			crc32 of structure starting with the next field
- * @ds_ifile_levels:		maximum number of levels for ifile
- * @ds_iblock_levels:		maximum number of levels for regular files
- * @ds_data_levels:		number of separate levels for data
- * @pad0:			reserved, must be 0
- * @ds_feature_incompat:	incompatible filesystem features
- * @ds_feature_ro_compat:	read-only compatible filesystem features
- * @ds_feature_compat:		compatible filesystem features
- * @ds_flags:			flags
- * @ds_segment_shift:		log2 of segment size
- * @ds_block_shift:		log2 of block size
- * @ds_write_shift:		log2 of write size
- * @pad1:			reserved, must be 0
- * @ds_journal_seg:		segments used by primary journal
- * @ds_root_reserve:		bytes reserved for the superuser
- * @ds_speed_reserve:		bytes reserved to speed up GC
- * @ds_bad_seg_reserve:		number of segments reserved to handle bad blocks
- * @pad2:			reserved, must be 0
- * @pad3:			reserved, must be 0
- *
- * Contains only read-only fields.  Read-write fields like the amount of used
- * space is tracked in the dynamic superblock, which is stored in the journal.
- */
-struct logfs_disk_super {
-	struct logfs_segment_header ds_sh;
-	__be64	ds_magic;
-
-	__be32	ds_crc;
-	__u8	ds_ifile_levels;
-	__u8	ds_iblock_levels;
-	__u8	ds_data_levels;
-	__u8	ds_segment_shift;
-	__u8	ds_block_shift;
-	__u8	ds_write_shift;
-	__u8	pad0[6];
-
-	__be64	ds_filesystem_size;
-	__be32	ds_segment_size;
-	__be32  ds_bad_seg_reserve;
-
-	__be64	ds_feature_incompat;
-	__be64	ds_feature_ro_compat;
-
-	__be64	ds_feature_compat;
-	__be64	ds_feature_flags;
-
-	__be64	ds_root_reserve;
-	__be64  ds_speed_reserve;
-
-	__be32	ds_journal_seg[LOGFS_JOURNAL_SEGS];
-
-	__be64	ds_super_ofs[2];
-	__be64	pad3[8];
-};
-
-SIZE_CHECK(logfs_disk_super, 256);
-
-/*
- * Object types:
- * OBJ_BLOCK	- Data or indirect block
- * OBJ_INODE	- Inode
- * OBJ_DENTRY	- Dentry
- */
-enum {
-	OBJ_BLOCK	= 0x04,
-	OBJ_INODE	= 0x05,
-	OBJ_DENTRY	= 0x06,
-};
-
-/**
- * struct logfs_object_header - per-object header in the ostore
- *
- * @crc:			crc32 of header, excluding data_crc
- * @len:			length of data
- * @type:			object type, see above
- * @compr:			compression type
- * @ino:			inode number
- * @bix:			block index
- * @data_crc:			crc32 of payload
- */
-struct logfs_object_header {
-	__be32	crc;
-	__be16	len;
-	__u8	type;
-	__u8	compr;
-	__be64	ino;
-	__be64	bix;
-	__be32	data_crc;
-} __attribute__((packed));
-
-SIZE_CHECK(logfs_object_header, LOGFS_OBJECT_HEADERSIZE);
-
-/*
- * Reserved inode numbers:
- * LOGFS_INO_MASTER	- master inode (for inode file)
- * LOGFS_INO_ROOT	- root directory
- * LOGFS_INO_SEGFILE	- per-segment used bytes and erase count
- */
-enum {
-	LOGFS_INO_MAPPING	= 0x00,
-	LOGFS_INO_MASTER	= 0x01,
-	LOGFS_INO_ROOT		= 0x02,
-	LOGFS_INO_SEGFILE	= 0x03,
-	LOGFS_RESERVED_INOS	= 0x10,
-};
-
-/*
- * Inode flags.  High bits should never be written to the medium.  They are
- * reserved for in-memory usage.
- * Low bits should either remain in sync with the corresponding FS_*_FL or
- * reuse slots that obviously don't make sense for logfs.
- *
- * LOGFS_IF_DIRTY	Inode must be written back
- * LOGFS_IF_ZOMBIE	Inode has been deleted
- * LOGFS_IF_STILLBORN	-ENOSPC happened when creating inode
- */
-#define LOGFS_IF_COMPRESSED	0x00000004 /* == FS_COMPR_FL */
-#define LOGFS_IF_DIRTY		0x20000000
-#define LOGFS_IF_ZOMBIE		0x40000000
-#define LOGFS_IF_STILLBORN	0x80000000
-
-/* Flags available to chattr */
-#define LOGFS_FL_USER_VISIBLE	(LOGFS_IF_COMPRESSED)
-#define LOGFS_FL_USER_MODIFIABLE (LOGFS_IF_COMPRESSED)
-/* Flags inherited from parent directory on file/directory creation */
-#define LOGFS_FL_INHERITED	(LOGFS_IF_COMPRESSED)
-
-/**
- * struct logfs_disk_inode - on-medium inode
- *
- * @di_mode:			file mode
- * @di_pad:			reserved, must be 0
- * @di_flags:			inode flags, see above
- * @di_uid:			user id
- * @di_gid:			group id
- * @di_ctime:			change time
- * @di_mtime:			modify time
- * @di_refcount:		reference count (aka nlink or link count)
- * @di_generation:		inode generation, for nfs
- * @di_used_bytes:		number of bytes used
- * @di_size:			file size
- * @di_data:			data pointers
- */
-struct logfs_disk_inode {
-	__be16	di_mode;
-	__u8	di_height;
-	__u8	di_pad;
-	__be32	di_flags;
-	__be32	di_uid;
-	__be32	di_gid;
-
-	__be64	di_ctime;
-	__be64	di_mtime;
-
-	__be64	di_atime;
-	__be32	di_refcount;
-	__be32	di_generation;
-
-	__be64	di_used_bytes;
-	__be64	di_size;
-
-	__be64	di_data[LOGFS_EMBEDDED_FIELDS];
-};
-
-SIZE_CHECK(logfs_disk_inode, 200);
-
-#define INODE_POINTER_OFS \
-	(offsetof(struct logfs_disk_inode, di_data) / sizeof(__be64))
-#define INODE_USED_OFS \
-	(offsetof(struct logfs_disk_inode, di_used_bytes) / sizeof(__be64))
-#define INODE_SIZE_OFS \
-	(offsetof(struct logfs_disk_inode, di_size) / sizeof(__be64))
-#define INODE_HEIGHT_OFS	(0)
-
-/**
- * struct logfs_disk_dentry - on-medium dentry structure
- *
- * @ino:			inode number
- * @namelen:			length of file name
- * @type:			file type, identical to bits 12..15 of mode
- * @name:			file name
- */
-/* FIXME: add 6 bytes of padding to remove the __packed */
-struct logfs_disk_dentry {
-	__be64	ino;
-	__be16	namelen;
-	__u8	type;
-	__u8	name[LOGFS_MAX_NAMELEN];
-} __attribute__((packed));
-
-SIZE_CHECK(logfs_disk_dentry, 266);
-
-#define RESERVED		0xffffffff
-#define BADSEG			0xffffffff
-/**
- * struct logfs_segment_entry - segment file entry
- *
- * @ec_level:			erase count and level
- * @valid:			number of valid bytes
- *
- * Segment file contains one entry for every segment.  ec_level contains the
- * erasecount in the upper 28 bits and the level in the lower 4 bits.  An
- * ec_level of BADSEG (-1) identifies bad segments.  valid contains the number
- * of valid bytes or RESERVED (-1 again) if the segment is used for either the
- * superblock or the journal, or when the segment is bad.
- */
-struct logfs_segment_entry {
-	__be32	ec_level;
-	__be32	valid;
-};
-
-SIZE_CHECK(logfs_segment_entry, 8);
-
-/**
- * struct logfs_journal_header - header for journal entries (JEs)
- *
- * @h_crc:			crc32 of journal entry
- * @h_len:			length of compressed journal entry,
- *				not including header
- * @h_datalen:			length of uncompressed data
- * @h_type:			JE type
- * @h_compr:			compression type
- * @h_pad:			reserved
- */
-struct logfs_journal_header {
-	__be32	h_crc;
-	__be16	h_len;
-	__be16	h_datalen;
-	__be16	h_type;
-	__u8	h_compr;
-	__u8	h_pad[5];
-};
-
-SIZE_CHECK(logfs_journal_header, 16);
-
-/*
- * Life expectency of data.
- * VIM_DEFAULT		- default vim
- * VIM_SEGFILE		- for segment file only - very short-living
- * VIM_GC		- GC'd data - likely long-living
- */
-enum logfs_vim {
-	VIM_DEFAULT	= 0,
-	VIM_SEGFILE	= 1,
-};
-
-/**
- * struct logfs_je_area - wbuf header
- *
- * @segno:			segment number of area
- * @used_bytes:			number of bytes already used
- * @gc_level:			GC level
- * @vim:			life expectancy of data
- *
- * "Areas" are segments currently being used for writing.  There is at least
- * one area per GC level.  Several may be used to separate long-living from
- * short-living data.  If an area with unknown vim is encountered, it can
- * simply be closed.
- * The write buffer immediately follow this header.
- */
-struct logfs_je_area {
-	__be32	segno;
-	__be32	used_bytes;
-	__u8	gc_level;
-	__u8	vim;
-} __attribute__((packed));
-
-SIZE_CHECK(logfs_je_area, 10);
-
-#define MAX_JOURNAL_HEADER \
-	(sizeof(struct logfs_journal_header) + sizeof(struct logfs_je_area))
-
-/**
- * struct logfs_je_dynsb - dynamic superblock
- *
- * @ds_gec:			global erase count
- * @ds_sweeper:			current position of GC "sweeper"
- * @ds_rename_dir:		source directory ino (see dir.c documentation)
- * @ds_rename_pos:		position of source dd (see dir.c documentation)
- * @ds_victim_ino:		victims of incomplete dir operation (see dir.c)
- * @ds_victim_ino:		parent inode of victim (see dir.c)
- * @ds_used_bytes:		number of used bytes
- */
-struct logfs_je_dynsb {
-	__be64	ds_gec;
-	__be64	ds_sweeper;
-
-	__be64	ds_rename_dir;
-	__be64	ds_rename_pos;
-
-	__be64	ds_victim_ino;
-	__be64	ds_victim_parent; /* XXX */
-
-	__be64	ds_used_bytes;
-	__be32	ds_generation;
-	__be32	pad;
-};
-
-SIZE_CHECK(logfs_je_dynsb, 64);
-
-/**
- * struct logfs_je_anchor - anchor of filesystem tree, aka master inode
- *
- * @da_size:			size of inode file
- * @da_last_ino:		last created inode
- * @da_used_bytes:		number of bytes used
- * @da_data:			data pointers
- */
-struct logfs_je_anchor {
-	__be64	da_size;
-	__be64	da_last_ino;
-
-	__be64	da_used_bytes;
-	u8	da_height;
-	u8	pad[7];
-
-	__be64	da_data[LOGFS_EMBEDDED_FIELDS];
-};
-
-SIZE_CHECK(logfs_je_anchor, 168);
-
-/**
- * struct logfs_je_spillout - spillout entry (from 1st to 2nd journal)
- *
- * @so_segment:			segments used for 2nd journal
- *
- * Length of the array is given by h_len field in the header.
- */
-struct logfs_je_spillout {
-	__be64	so_segment[0];
-};
-
-SIZE_CHECK(logfs_je_spillout, 0);
-
-/**
- * struct logfs_je_journal_ec - erase counts for all journal segments
- *
- * @ec:				erase count
- *
- * Length of the array is given by h_len field in the header.
- */
-struct logfs_je_journal_ec {
-	__be32	ec[0];
-};
-
-SIZE_CHECK(logfs_je_journal_ec, 0);
-
-/**
- * struct logfs_je_free_segments - list of free segmetns with erase count
- */
-struct logfs_je_free_segments {
-	__be32	segno;
-	__be32	ec;
-};
-
-SIZE_CHECK(logfs_je_free_segments, 8);
-
-/**
- * struct logfs_seg_alias - list of segment aliases
- */
-struct logfs_seg_alias {
-	__be32	old_segno;
-	__be32	new_segno;
-};
-
-SIZE_CHECK(logfs_seg_alias, 8);
-
-/**
- * struct logfs_obj_alias - list of object aliases
- */
-struct logfs_obj_alias {
-	__be64	ino;
-	__be64	bix;
-	__be64	val;
-	u8	level;
-	u8	pad[5];
-	__be16	child_no;
-};
-
-SIZE_CHECK(logfs_obj_alias, 32);
-
-/**
- * Compression types.
- *
- * COMPR_NONE	- uncompressed
- * COMPR_ZLIB	- compressed with zlib
- */
-enum {
-	COMPR_NONE	= 0,
-	COMPR_ZLIB	= 1,
-};
-
-/*
- * Journal entries come in groups of 16.  First group contains unique
- * entries, next groups contain one entry per level
- *
- * JE_FIRST	- smallest possible journal entry number
- *
- * JEG_BASE	- base group, containing unique entries
- * JE_COMMIT	- commit entry, validates all previous entries
- * JE_DYNSB	- dynamic superblock, anything that ought to be in the
- *		  superblock but cannot because it is read-write data
- * JE_ANCHOR	- anchor aka master inode aka inode file's inode
- * JE_ERASECOUNT  erasecounts for all journal segments
- * JE_SPILLOUT	- unused
- * JE_SEG_ALIAS	- aliases segments
- * JE_AREA	- area description
- *
- * JE_LAST	- largest possible journal entry number
- */
-enum {
-	JE_FIRST	= 0x01,
-
-	JEG_BASE	= 0x00,
-	JE_COMMIT	= 0x02,
-	JE_DYNSB	= 0x03,
-	JE_ANCHOR	= 0x04,
-	JE_ERASECOUNT	= 0x05,
-	JE_SPILLOUT	= 0x06,
-	JE_OBJ_ALIAS	= 0x0d,
-	JE_AREA		= 0x0e,
-
-	JE_LAST		= 0x0e,
-};
-
-#endif

fs/logfs/readwrite.c

···
-/*
- * fs/logfs/readwrite.c
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- *
- *
- * Actually contains five sets of very similar functions:
- * read		read blocks from a file
- * seek_hole	find next hole
- * seek_data	find next data block
- * valid	check whether a block still belongs to a file
- * write	write blocks to a file
- * delete	delete a block (for directories and ifile)
- * rewrite	move existing blocks of a file to a new location (gc helper)
- * truncate	truncate a file
- */
-#include "logfs.h"
-#include <linux/sched.h>
-#include <linux/slab.h>
-
-static u64 adjust_bix(u64 bix, level_t level)
-{
-	switch (level) {
-	case 0:
-		return bix;
-	case LEVEL(1):
-		return max_t(u64, bix, I0_BLOCKS);
-	case LEVEL(2):
-		return max_t(u64, bix, I1_BLOCKS);
-	case LEVEL(3):
-		return max_t(u64, bix, I2_BLOCKS);
-	case LEVEL(4):
-		return max_t(u64, bix, I3_BLOCKS);
-	case LEVEL(5):
-		return max_t(u64, bix, I4_BLOCKS);
-	default:
-		WARN_ON(1);
-		return bix;
-	}
-}
-
-static inline u64 maxbix(u8 height)
-{
-	return 1ULL << (LOGFS_BLOCK_BITS * height);
-}
-
-/**
- * The inode address space is cut in two halves.  Lower half belongs to data
- * pages, upper half to indirect blocks.  If the high bit (INDIRECT_BIT) is
- * set, the actual block index (bix) and level can be derived from the page
- * index.
- *
- * The lowest three bits of the block index are set to 0 after packing and
- * unpacking.  Since the lowest n bits (9 for 4KiB blocksize) are ignored
- * anyway this is harmless.
- */
-#define ARCH_SHIFT	(BITS_PER_LONG - 32)
-#define INDIRECT_BIT	(0x80000000UL << ARCH_SHIFT)
-#define LEVEL_SHIFT	(28 + ARCH_SHIFT)
-static inline pgoff_t first_indirect_block(void)
-{
-	return INDIRECT_BIT | (1ULL << LEVEL_SHIFT);
-}
-
-pgoff_t logfs_pack_index(u64 bix, level_t level)
-{
-	pgoff_t index;
-
-	BUG_ON(bix >= INDIRECT_BIT);
-	if (level == 0)
-		return bix;
-
-	index  = INDIRECT_BIT;
-	index |= (__force long)level << LEVEL_SHIFT;
-	index |= bix >> ((__force u8)level * LOGFS_BLOCK_BITS);
-	return index;
-}
-
-void logfs_unpack_index(pgoff_t index, u64 *bix, level_t *level)
-{
-	u8 __level;
-
-	if (!(index & INDIRECT_BIT)) {
-		*bix = index;
-		*level = 0;
-		return;
-	}
-
-	__level = (index & ~INDIRECT_BIT) >> LEVEL_SHIFT;
-	*level = LEVEL(__level);
-	*bix = (index << (__level * LOGFS_BLOCK_BITS)) & ~INDIRECT_BIT;
-	*bix = adjust_bix(*bix, *level);
-	return;
-}
-#undef ARCH_SHIFT
-#undef INDIRECT_BIT
-#undef LEVEL_SHIFT
-
-/*
- * Time is stored as nanoseconds since the epoch.
- */
-static struct timespec be64_to_timespec(__be64 betime)
-{
-	return ns_to_timespec(be64_to_cpu(betime));
-}
-
-static __be64 timespec_to_be64(struct timespec tsp)
-{
-	return cpu_to_be64((u64)tsp.tv_sec * NSEC_PER_SEC + tsp.tv_nsec);
-}
-
-static void logfs_disk_to_inode(struct logfs_disk_inode *di, struct inode*inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	int i;
-
-	inode->i_mode	= be16_to_cpu(di->di_mode);
-	li->li_height	= di->di_height;
-	li->li_flags	= be32_to_cpu(di->di_flags);
-	i_uid_write(inode, be32_to_cpu(di->di_uid));
-	i_gid_write(inode, be32_to_cpu(di->di_gid));
-	inode->i_size	= be64_to_cpu(di->di_size);
-	logfs_set_blocks(inode, be64_to_cpu(di->di_used_bytes));
-	inode->i_atime	= be64_to_timespec(di->di_atime);
-	inode->i_ctime	= be64_to_timespec(di->di_ctime);
-	inode->i_mtime	= be64_to_timespec(di->di_mtime);
-	set_nlink(inode, be32_to_cpu(di->di_refcount));
-	inode->i_generation = be32_to_cpu(di->di_generation);
-
-	switch (inode->i_mode & S_IFMT) {
-	case S_IFSOCK:	/* fall through */
-	case S_IFBLK:	/* fall through */
-	case S_IFCHR:	/* fall through */
-	case S_IFIFO:
-		inode->i_rdev = be64_to_cpu(di->di_data[0]);
-		break;
-	case S_IFDIR:	/* fall through */
-	case S_IFREG:	/* fall through */
-	case S_IFLNK:
-		for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
-			li->li_data[i] = be64_to_cpu(di->di_data[i]);
-		break;
-	default:
-		BUG();
-	}
-}
-
-static void logfs_inode_to_disk(struct inode *inode, struct logfs_disk_inode*di)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	int i;
-
-	di->di_mode	= cpu_to_be16(inode->i_mode);
-	di->di_height	= li->li_height;
-	di->di_pad	= 0;
-	di->di_flags	= cpu_to_be32(li->li_flags);
-	di->di_uid	= cpu_to_be32(i_uid_read(inode));
-	di->di_gid	= cpu_to_be32(i_gid_read(inode));
-	di->di_size	= cpu_to_be64(i_size_read(inode));
-	di->di_used_bytes = cpu_to_be64(li->li_used_bytes);
-	di->di_atime	= timespec_to_be64(inode->i_atime);
-	di->di_ctime	= timespec_to_be64(inode->i_ctime);
-	di->di_mtime	= timespec_to_be64(inode->i_mtime);
-	di->di_refcount	= cpu_to_be32(inode->i_nlink);
-	di->di_generation = cpu_to_be32(inode->i_generation);
-
-	switch (inode->i_mode & S_IFMT) {
-	case S_IFSOCK:	/* fall through */
-	case S_IFBLK:	/* fall through */
-	case S_IFCHR:	/* fall through */
-	case S_IFIFO:
-		di->di_data[0] = cpu_to_be64(inode->i_rdev);
-		break;
-	case S_IFDIR:	/* fall through */
-	case S_IFREG:	/* fall through */
-	case S_IFLNK:
-		for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
-			di->di_data[i] = cpu_to_be64(li->li_data[i]);
-		break;
-	default:
-		BUG();
-	}
-}
-
-static void __logfs_set_blocks(struct inode *inode)
-{
-	struct super_block *sb = inode->i_sb;
-	struct logfs_inode *li = logfs_inode(inode);
-
-	inode->i_blocks = ULONG_MAX;
-	if (li->li_used_bytes >> sb->s_blocksize_bits < ULONG_MAX)
-		inode->i_blocks = ALIGN(li->li_used_bytes, 512) >> 9;
-}
-
-void logfs_set_blocks(struct inode *inode, u64 bytes)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-
-	li->li_used_bytes = bytes;
-	__logfs_set_blocks(inode);
-}
-
-static void prelock_page(struct super_block *sb, struct page *page, int lock)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	BUG_ON(!PageLocked(page));
-	if (lock) {
-		BUG_ON(PagePreLocked(page));
-		SetPagePreLocked(page);
-	} else {
-		/* We are in GC path. */
-		if (PagePreLocked(page))
-			super->s_lock_count++;
-		else
-			SetPagePreLocked(page);
-	}
-}
-
-static void preunlock_page(struct super_block *sb, struct page *page, int lock)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	BUG_ON(!PageLocked(page));
-	if (lock)
-		ClearPagePreLocked(page);
-	else {
-		/* We are in GC path. */
-		BUG_ON(!PagePreLocked(page));
-		if (super->s_lock_count)
-			super->s_lock_count--;
-		else
-			ClearPagePreLocked(page);
-	}
-}
-
-/*
- * Logfs is prone to an AB-BA deadlock where one task tries to acquire
- * s_write_mutex with a locked page and GC tries to get that page while holding
- * s_write_mutex.
- * To solve this issue logfs will ignore the page lock iff the page in question
- * is waiting for s_write_mutex.  We annotate this fact by setting PG_pre_locked
- * in addition to PG_locked.
- */
-void logfs_get_wblocks(struct super_block *sb, struct page *page, int lock)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	if (page)
-		prelock_page(sb, page, lock);
-
-	if (lock) {
-		mutex_lock(&super->s_write_mutex);
-		logfs_gc_pass(sb);
-		/* FIXME: We also have to check for shadowed space
-		 * and mempool fill grade */
-	}
-}
-
-void logfs_put_wblocks(struct super_block *sb, struct page *page, int lock)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	if (page)
-		preunlock_page(sb, page, lock);
-	/* Order matters - we must clear PG_pre_locked before releasing
-	 * s_write_mutex or we could race against another task. */
-	if (lock)
-		mutex_unlock(&super->s_write_mutex);
-}
-
-static struct page *logfs_get_read_page(struct inode *inode, u64 bix,
-		level_t level)
-{
-	return find_or_create_page(inode->i_mapping,
-			logfs_pack_index(bix, level), GFP_NOFS);
-}
-
-static void logfs_put_read_page(struct page *page)
-{
-	unlock_page(page);
-	put_page(page);
-}
-
-static void logfs_lock_write_page(struct page *page)
-{
-	int loop = 0;
-
-	while (unlikely(!trylock_page(page))) {
-		if (loop++ > 0x1000) {
-			/* Has been observed once so far... */
-			printk(KERN_ERR "stack at %p\n", &loop);
-			BUG();
-		}
-		if (PagePreLocked(page)) {
-			/* Holder of page lock is waiting for us, it
-			 * is safe to use this page. */
-			break;
-		}
-		/* Some other process has this page locked and has
-		 * nothing to do with us.  Wait for it to finish.
-		 */
-		schedule();
-	}
-	BUG_ON(!PageLocked(page));
-}
-
-static struct page *logfs_get_write_page(struct inode *inode, u64 bix,
-		level_t level)
-{
-	struct address_space *mapping = inode->i_mapping;
-	pgoff_t index = logfs_pack_index(bix, level);
-	struct page *page;
-	int err;
-
-repeat:
-	page = find_get_page(mapping, index);
-	if (!page) {
-		page = __page_cache_alloc(GFP_NOFS);
-		if (!page)
-			return NULL;
-		err = add_to_page_cache_lru(page, mapping, index, GFP_NOFS);
-		if (unlikely(err)) {
-			put_page(page);
-			if (err == -EEXIST)
-				goto repeat;
-			return NULL;
-		}
-	} else logfs_lock_write_page(page);
-	BUG_ON(!PageLocked(page));
-	return page;
-}
-
-static void logfs_unlock_write_page(struct page *page)
-{
-	if (!PagePreLocked(page))
-		unlock_page(page);
-}
-
-static void logfs_put_write_page(struct page *page)
-{
-	logfs_unlock_write_page(page);
-	put_page(page);
-}
-
-static struct page *logfs_get_page(struct inode *inode, u64 bix, level_t level,
-		int rw)
-{
-	if (rw == READ)
-		return logfs_get_read_page(inode, bix, level);
-	else
-		return logfs_get_write_page(inode, bix, level);
-}
-
-static void logfs_put_page(struct page *page, int rw)
-{
-	if (rw == READ)
-		logfs_put_read_page(page);
-	else
-		logfs_put_write_page(page);
-}
-
-static unsigned long __get_bits(u64 val, int skip, int no)
-{
-	u64 ret = val;
-
-	ret >>= skip * no;
-	ret <<= 64 - no;
-	ret >>= 64 - no;
-	return ret;
-}
-
-static unsigned long get_bits(u64 val, level_t skip)
-{
-	return __get_bits(val, (__force int)skip, LOGFS_BLOCK_BITS);
-}
-
-static inline void init_shadow_tree(struct super_block *sb,
-		struct shadow_tree *tree)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	btree_init_mempool64(&tree->new, super->s_btree_pool);
-	btree_init_mempool64(&tree->old, super->s_btree_pool);
-}
-
-static void indirect_write_block(struct logfs_block *block)
-{
-	struct page *page;
-	struct inode *inode;
-	int ret;
-
-	page = block->page;
-	inode = page->mapping->host;
-	logfs_lock_write_page(page);
-	ret = logfs_write_buf(inode, page, 0);
-	logfs_unlock_write_page(page);
-	/*
-	 * This needs some rework.  Unless you want your filesystem to run
-	 * completely synchronously (you don't), the filesystem will always
-	 * report writes as 'successful' before the actual work has been
-	 * done.  The actual work gets done here and this is where any errors
-	 * will show up.  And there isn't much we can do about it, really.
-	 *
-	 * Some attempts to fix the errors (move from bad blocks, retry io,...)
-	 * have already been done, so anything left should be either a broken
-	 * device or a bug somewhere in logfs itself.  Being relatively new,
-	 * the odds currently favor a bug, so for now the line below isn't
-	 * entirely tasteles.
-	 */
-	BUG_ON(ret);
-}
-
-static void inode_write_block(struct logfs_block *block)
-{
-	struct inode *inode;
-	int ret;
-
-	inode = block->inode;
-	if (inode->i_ino == LOGFS_INO_MASTER)
-		logfs_write_anchor(inode->i_sb);
-	else {
-		ret = __logfs_write_inode(inode, NULL, 0);
-		/* see indirect_write_block comment */
-		BUG_ON(ret);
-	}
-}
-
-/*
- * This silences a false, yet annoying gcc warning.  I hate it when my editor
- * jumps into bitops.h each time I recompile this file.
- * TODO: Complain to gcc folks about this and upgrade compiler.
- */
-static unsigned long fnb(const unsigned long *addr,
-		unsigned long size, unsigned long offset)
-{
-	return find_next_bit(addr, size, offset);
-}
-
-static __be64 inode_val0(struct inode *inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	u64 val;
-
-	/*
-	 * Explicit shifting generates good code, but must match the format
-	 * of the structure.  Add some paranoia just in case.
-	 */
-	BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_mode) != 0);
-	BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_height) != 2);
-	BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_flags) != 4);
-
-	val =	(u64)inode->i_mode << 48 |
-		(u64)li->li_height << 40 |
-		(u64)li->li_flags;
-	return cpu_to_be64(val);
-}
-
-static int inode_write_alias(struct super_block *sb,
-		struct logfs_block *block, write_alias_t *write_one_alias)
-{
-	struct inode *inode = block->inode;
-	struct logfs_inode *li = logfs_inode(inode);
-	unsigned long pos;
-	u64 ino , bix;
-	__be64 val;
-	level_t level;
-	int err;
-
-	for (pos = 0; ; pos++) {
-		pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos);
-		if (pos >= LOGFS_EMBEDDED_FIELDS + INODE_POINTER_OFS)
-			return 0;
-
-		switch (pos) {
-		case INODE_HEIGHT_OFS:
-			val = inode_val0(inode);
-			break;
-		case INODE_USED_OFS:
-			val = cpu_to_be64(li->li_used_bytes);
-			break;
-		case INODE_SIZE_OFS:
-			val = cpu_to_be64(i_size_read(inode));
-			break;
-		case INODE_POINTER_OFS ... INODE_POINTER_OFS + LOGFS_EMBEDDED_FIELDS - 1:
-			val = cpu_to_be64(li->li_data[pos - INODE_POINTER_OFS]);
-			break;
-		default:
-			BUG();
-		}
-
-		ino = LOGFS_INO_MASTER;
-		bix = inode->i_ino;
-		level = LEVEL(0);
-		err = write_one_alias(sb, ino, bix, level, pos, val);
-		if (err)
-			return err;
-	}
-}
-
-static int indirect_write_alias(struct super_block *sb,
-		struct logfs_block *block, write_alias_t *write_one_alias)
-{
-	unsigned long pos;
-	struct page *page = block->page;
-	u64 ino , bix;
-	__be64 *child, val;
-	level_t level;
-	int err;
-
-	for (pos = 0; ; pos++) {
-		pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos);
-		if (pos >= LOGFS_BLOCK_FACTOR)
-			return 0;
-
-		ino = page->mapping->host->i_ino;
-		logfs_unpack_index(page->index, &bix, &level);
-		child = kmap_atomic(page);
-		val = child[pos];
-		kunmap_atomic(child);
-		err = write_one_alias(sb, ino, bix, level, pos, val);
-		if (err)
-			return err;
-	}
-}
-
-int logfs_write_obj_aliases_pagecache(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_block *block;
-	int err;
-
-	list_for_each_entry(block, &super->s_object_alias, alias_list) {
-		err = block->ops->write_alias(sb, block, write_alias_journal);
-		if (err)
-			return err;
-	}
-	return 0;
-}
-
-void __free_block(struct super_block *sb, struct logfs_block *block)
-{
-	BUG_ON(!list_empty(&block->item_list));
-	list_del(&block->alias_list);
-	mempool_free(block, logfs_super(sb)->s_block_pool);
-}
-
-static void inode_free_block(struct super_block *sb, struct logfs_block *block)
-{
-	struct inode *inode = block->inode;
-
-	logfs_inode(inode)->li_block = NULL;
-	__free_block(sb, block);
-}
-
-static void indirect_free_block(struct super_block *sb,
-		struct logfs_block *block)
-{
-	struct page *page = block->page;
-
-	if (PagePrivate(page)) {
-		ClearPagePrivate(page);
-		put_page(page);
-		set_page_private(page, 0);
-	}
-	__free_block(sb, block);
-}
-
-
-static const struct logfs_block_ops inode_block_ops = {
-	.write_block = inode_write_block,
-	.free_block = inode_free_block,
-	.write_alias = inode_write_alias,
-};
-
-const struct logfs_block_ops indirect_block_ops = {
-	.write_block = indirect_write_block,
-	.free_block = indirect_free_block,
-	.write_alias = indirect_write_alias,
-};
-
-struct logfs_block *__alloc_block(struct super_block *sb,
-		u64 ino, u64 bix, level_t level)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_block *block;
-
-	block = mempool_alloc(super->s_block_pool, GFP_NOFS);
-	memset(block, 0, sizeof(*block));
-	INIT_LIST_HEAD(&block->alias_list);
-	INIT_LIST_HEAD(&block->item_list);
-	block->sb = sb;
-	block->ino = ino;
-	block->bix = bix;
-	block->level = level;
-	return block;
-}
-
-static void alloc_inode_block(struct inode *inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	struct logfs_block *block;
-
-	if (li->li_block)
-		return;
-
-	block = __alloc_block(inode->i_sb, LOGFS_INO_MASTER, inode->i_ino, 0);
-	block->inode = inode;
-	li->li_block = block;
-	block->ops = &inode_block_ops;
-}
-
-void initialize_block_counters(struct page *page, struct logfs_block *block,
-		__be64 *array, int page_is_empty)
-{
-	u64 ptr;
-	int i, start;
-
-	block->partial = 0;
-	block->full = 0;
-	start = 0;
-	if (page->index < first_indirect_block()) {
-		/* Counters are pointless on level 0 */
-		return;
-	}
-	if (page->index == first_indirect_block()) {
-		/* Skip unused pointers */
-		start = I0_BLOCKS;
-		block->full = I0_BLOCKS;
-	}
-	if (!page_is_empty) {
-		for (i = start; i < LOGFS_BLOCK_FACTOR; i++) {
-			ptr = be64_to_cpu(array[i]);
-			if (ptr)
-				block->partial++;
-			if (ptr & LOGFS_FULLY_POPULATED)
-				block->full++;
-		}
-	}
-}
-
-static void alloc_data_block(struct inode *inode, struct page *page)
-{
-	struct logfs_block *block;
-	u64 bix;
-	level_t level;
-
-	if (PagePrivate(page))
-		return;
-
-	logfs_unpack_index(page->index, &bix, &level);
-	block = __alloc_block(inode->i_sb, inode->i_ino, bix, level);
-	block->page = page;
-
-	SetPagePrivate(page);
-	get_page(page);
-	set_page_private(page, (unsigned long) block);
-
-	block->ops = &indirect_block_ops;
-}
-
-static void alloc_indirect_block(struct inode *inode, struct page *page,
-		int page_is_empty)
-{
-	struct logfs_block *block;
-	__be64 *array;
-
-	if (PagePrivate(page))
-		return;
-
-	alloc_data_block(inode, page);
-
-	block = logfs_block(page);
-	array = kmap_atomic(page);
-	initialize_block_counters(page, block, array, page_is_empty);
-	kunmap_atomic(array);
-}
-
-static void block_set_pointer(struct page *page, int index, u64 ptr)
-{
-	struct logfs_block *block = logfs_block(page);
-	__be64 *array;
-	u64 oldptr;
-
-	BUG_ON(!block);
-	array = kmap_atomic(page);
-	oldptr = be64_to_cpu(array[index]);
-	array[index] = cpu_to_be64(ptr);
-	kunmap_atomic(array);
-	SetPageUptodate(page);
-
-	block->full += !!(ptr & LOGFS_FULLY_POPULATED)
-		- !!(oldptr & LOGFS_FULLY_POPULATED);
-	block->partial += !!ptr - !!oldptr;
-}
-
-static u64 block_get_pointer(struct page *page, int index)
-{
-	__be64 *block;
-	u64 ptr;
-
-	block = kmap_atomic(page);
-	ptr = be64_to_cpu(block[index]);
-	kunmap_atomic(block);
-	return ptr;
-}
-
-static int logfs_read_empty(struct page *page)
-{
-	zero_user_segment(page, 0, PAGE_SIZE);
-	return 0;
-}
-
-static int logfs_read_direct(struct inode *inode, struct page *page)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	pgoff_t index = page->index;
-	u64 block;
-
-	block = li->li_data[index];
-	if (!block)
-		return logfs_read_empty(page);
-
-	return logfs_segment_read(inode, page, block, index, 0);
-}
-
-static int logfs_read_loop(struct inode *inode, struct page *page,
-		int rw_context)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	u64 bix, bofs = li->li_data[INDIRECT_INDEX];
-	level_t level, target_level;
-	int ret;
-	struct page *ipage;
-
-	logfs_unpack_index(page->index, &bix, &target_level);
-	if (!bofs)
-		return logfs_read_empty(page);
-
-	if (bix >= maxbix(li->li_height))
-		return logfs_read_empty(page);
-
-	for (level = LEVEL(li->li_height);
-			(__force u8)level > (__force u8)target_level;
-			level = SUBLEVEL(level)){
-		ipage = logfs_get_page(inode, bix, level, rw_context);
-		if (!ipage)
-			return -ENOMEM;
-
-		ret = logfs_segment_read(inode, ipage, bofs, bix, level);
-		if (ret) {
-			logfs_put_read_page(ipage);
-			return ret;
-		}
-
-		bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level)));
-		logfs_put_page(ipage, rw_context);
-		if (!bofs)
-			return logfs_read_empty(page);
-	}
-
-	return logfs_segment_read(inode, page, bofs, bix, 0);
-}
-
-static int logfs_read_block(struct inode *inode, struct page *page,
-		int rw_context)
-{
-	pgoff_t index = page->index;
-
-	if (index < I0_BLOCKS)
-		return logfs_read_direct(inode, page);
-	return logfs_read_loop(inode, page, rw_context);
-}
-
-static int logfs_exist_loop(struct inode *inode, u64 bix)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	u64 bofs = li->li_data[INDIRECT_INDEX];
-	level_t level;
-	int ret;
-	struct page *ipage;
-
-	if (!bofs)
-		return 0;
-	if (bix >= maxbix(li->li_height))
-		return 0;
-
-	for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) {
-		ipage = logfs_get_read_page(inode, bix, level);
-		if (!ipage)
-			return -ENOMEM;
-
-		ret = logfs_segment_read(inode, ipage, bofs, bix, level);
-		if (ret) {
-			logfs_put_read_page(ipage);
-			return ret;
-		}
-
-		bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level)));
-		logfs_put_read_page(ipage);
-		if (!bofs)
-			return 0;
-	}
-
-	return 1;
-}
-
-int logfs_exist_block(struct inode *inode, u64 bix)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-
-	if (bix < I0_BLOCKS)
-		return !!li->li_data[bix];
-	return logfs_exist_loop(inode, bix);
-}
-
-static u64 seek_holedata_direct(struct inode *inode, u64 bix, int data)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-
-	for (; bix < I0_BLOCKS; bix++)
-		if (data ^ (li->li_data[bix] == 0))
-			return bix;
-	return I0_BLOCKS;
-}
-
-static u64 seek_holedata_loop(struct inode *inode, u64 bix, int data)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	__be64 *rblock;
-	u64 increment, bofs = li->li_data[INDIRECT_INDEX];
-	level_t level;
-	int ret, slot;
-	struct page *page;
-
-	BUG_ON(!bofs);
-
-	for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) {
-		increment = 1 << (LOGFS_BLOCK_BITS * ((__force u8)level-1));
-		page = logfs_get_read_page(inode, bix, level);
-		if (!page)
-			return bix;
-
-		ret = logfs_segment_read(inode, page, bofs, bix, level);
-		if (ret) {
-			logfs_put_read_page(page);
-			return bix;
-		}
-
-		slot = get_bits(bix, SUBLEVEL(level));
-		rblock = kmap_atomic(page);
-		while (slot < LOGFS_BLOCK_FACTOR) {
-			if (data && (rblock[slot] != 0))
-				break;
-			if (!data && !(be64_to_cpu(rblock[slot]) & LOGFS_FULLY_POPULATED))
-				break;
-			slot++;
-			bix += increment;
-			bix &= ~(increment - 1);
-		}
-		if (slot >= LOGFS_BLOCK_FACTOR) {
-			kunmap_atomic(rblock);
-			logfs_put_read_page(page);
-			return bix;
-		}
-		bofs = be64_to_cpu(rblock[slot]);
-		kunmap_atomic(rblock);
-		logfs_put_read_page(page);
-		if (!bofs) {
-			BUG_ON(data);
-			return bix;
-		}
-	}
-	return bix;
-}
-
-/**
- * logfs_seek_hole - find next hole starting at a given block index
- * @inode:		inode to search in
- * @bix:		block index to start searching
- *
- * Returns next hole.  If the file doesn't contain any further holes, the
- * block address next to eof is returned instead.
- */
-u64 logfs_seek_hole(struct inode *inode, u64 bix)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-
-	if (bix < I0_BLOCKS) {
-		bix = seek_holedata_direct(inode, bix, 0);
-		if (bix < I0_BLOCKS)
-			return bix;
-	}
-
-	if (!li->li_data[INDIRECT_INDEX])
-		return bix;
-	else if (li->li_data[INDIRECT_INDEX] & LOGFS_FULLY_POPULATED)
-		bix = maxbix(li->li_height);
-	else if (bix >= maxbix(li->li_height))
-		return bix;
-	else {
-		bix = seek_holedata_loop(inode, bix, 0);
-		if (bix < maxbix(li->li_height))
-			return bix;
-		/* Should not happen anymore.  But if some port writes semi-
-		 * corrupt images (as this one used to) we might run into it.
-		 */
-		WARN_ON_ONCE(bix == maxbix(li->li_height));
-	}
-
-	return bix;
-}
-
-static u64 __logfs_seek_data(struct inode *inode, u64 bix)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-
-	if (bix < I0_BLOCKS) {
-		bix = seek_holedata_direct(inode, bix, 1);
-		if (bix < I0_BLOCKS)
-			return bix;
-	}
-
-	if (bix < maxbix(li->li_height)) {
-		if (!li->li_data[INDIRECT_INDEX])
-			bix = maxbix(li->li_height);
-		else
-			return seek_holedata_loop(inode, bix, 1);
-	}
-
-	return bix;
-}
-
-/**
- * logfs_seek_data - find next data block after a given block index
- * @inode:		inode to search in
- * @bix:		block index to start searching
- *
- * Returns next data block.  If the file doesn't contain any further data
- * blocks, the last block in the file is returned instead.
- */
-u64 logfs_seek_data(struct inode *inode, u64 bix)
-{
-	struct super_block *sb = inode->i_sb;
-	u64 ret, end;
-
-	ret = __logfs_seek_data(inode, bix);
-	end = i_size_read(inode) >> sb->s_blocksize_bits;
-	if (ret >= end)
-		ret = max(bix, end);
-	return ret;
-}
-
-static int logfs_is_valid_direct(struct logfs_inode *li, u64 bix, u64 ofs)
-{
-	return pure_ofs(li->li_data[bix]) == ofs;
-}
-
-static int __logfs_is_valid_loop(struct inode *inode, u64 bix,
-		u64 ofs, u64 bofs)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	level_t level;
-	int ret;
-	struct page *page;
-
-	for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)){
-		page = logfs_get_write_page(inode, bix, level);
-		BUG_ON(!page);
-
-		ret = logfs_segment_read(inode, page, bofs, bix, level);
-		if (ret) {
-			logfs_put_write_page(page);
-			return 0;
-		}
-
-		bofs = block_get_pointer(page, get_bits(bix, SUBLEVEL(level)));
-		logfs_put_write_page(page);
-		if (!bofs)
-			return 0;
-
-		if (pure_ofs(bofs) == ofs)
-			return 1;
-	}
-	return 0;
-}
-
-static int logfs_is_valid_loop(struct inode *inode, u64 bix, u64 ofs)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	u64 bofs = li->li_data[INDIRECT_INDEX];
-
-	if (!bofs)
-		return 0;
-
-	if (bix >= maxbix(li->li_height))
-		return 0;
-
-	if (pure_ofs(bofs) == ofs)
-		return 1;
-
-	return __logfs_is_valid_loop(inode, bix, ofs, bofs);
-}
-
-static int __logfs_is_valid_block(struct inode *inode, u64 bix, u64 ofs)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-
-	if ((inode->i_nlink == 0) && atomic_read(&inode->i_count) == 1)
-		return 0;
-
-	if (bix < I0_BLOCKS)
-		return logfs_is_valid_direct(li, bix, ofs);
-	return logfs_is_valid_loop(inode, bix, ofs);
-}
-
-/**
- * logfs_is_valid_block - check whether this block is still valid
- *
- * @sb:		superblock
- * @ofs:	block physical offset
- * @ino:	block inode number
- * @bix:	block index
- * @gc_level:	block level
- *
- * Returns 0 if the block is invalid, 1 if it is valid and 2 if it will
- * become invalid once the journal is written.
- */
-int logfs_is_valid_block(struct super_block *sb, u64 ofs, u64 ino, u64 bix,
-		gc_level_t gc_level)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct inode *inode;
-	int ret, cookie;
-
-	/* Umount closes a segment with free blocks remaining.  Those
-	 * blocks are by definition invalid. */
-	if (ino == -1)
-		return 0;
-
-	LOGFS_BUG_ON((u64)(u_long)ino != ino, sb);
-
-	inode = logfs_safe_iget(sb, ino, &cookie);
-	if (IS_ERR(inode))
-		goto invalid;
-
-	ret = __logfs_is_valid_block(inode, bix, ofs);
-	logfs_safe_iput(inode, cookie);
-	if (ret)
-		return ret;
-
-invalid:
-	/* Block is nominally invalid, but may still sit in the shadow tree,
-	 * waiting for a journal commit.
-	 */
-	if (btree_lookup64(&super->s_shadow_tree.old, ofs))
-		return 2;
-	return 0;
-}
-
-int logfs_readpage_nolock(struct page *page)
-{
-	struct inode *inode = page->mapping->host;
-	int ret = -EIO;
-
-	ret = logfs_read_block(inode, page, READ);
-
-	if (ret) {
-		ClearPageUptodate(page);
-		SetPageError(page);
-	} else {
-		SetPageUptodate(page);
-		ClearPageError(page);
-	}
-	flush_dcache_page(page);
-
-	return ret;
-}
-
-static int logfs_reserve_bytes(struct inode *inode, int bytes)
-{
-	struct logfs_super *super = logfs_super(inode->i_sb);
-	u64 available = super->s_free_bytes + super->s_dirty_free_bytes
-			- super->s_dirty_used_bytes - super->s_dirty_pages;
-
-	if (!bytes)
-		return 0;
-
-	if (available < bytes)
-		return -ENOSPC;
-
-	if (available < bytes + super->s_root_reserve &&
-			!capable(CAP_SYS_RESOURCE))
-		return -ENOSPC;
-
-	return 0;
-}
-
-int get_page_reserve(struct inode *inode, struct page *page)
-{
-	struct logfs_super *super = logfs_super(inode->i_sb);
-	struct logfs_block *block = logfs_block(page);
-	int ret;
-
-	if (block && block->reserved_bytes)
-		return 0;
-
-	logfs_get_wblocks(inode->i_sb, page, WF_LOCK);
-	while ((ret = logfs_reserve_bytes(inode, 6 * LOGFS_MAX_OBJECTSIZE)) &&
-			!list_empty(&super->s_writeback_list)) {
-		block = list_entry(super->s_writeback_list.next,
-				struct logfs_block, alias_list);
-		block->ops->write_block(block);
-	}
-	if (!ret) {
-		alloc_data_block(inode, page);
-		block = logfs_block(page);
-		block->reserved_bytes += 6 * LOGFS_MAX_OBJECTSIZE;
-		super->s_dirty_pages += 6 * LOGFS_MAX_OBJECTSIZE;
-		list_move_tail(&block->alias_list, &super->s_writeback_list);
-	}
-	logfs_put_wblocks(inode->i_sb, page, WF_LOCK);
-	return ret;
-}
-
-/*
- * We are protected by write lock.  Push victims up to superblock level
- * and release transaction when appropriate.
- */
-/* FIXME: This is currently called from the wrong spots. */
-static void logfs_handle_transaction(struct inode *inode,
-		struct logfs_transaction *ta)
-{
-	struct logfs_super *super = logfs_super(inode->i_sb);
-
-	if (!ta)
-		return;
-	logfs_inode(inode)->li_block->ta = NULL;
-
-	if (inode->i_ino != LOGFS_INO_MASTER) {
-		BUG(); /* FIXME: Yes, this needs more thought */
-		/* just remember the transaction until inode is written */
-		//BUG_ON(logfs_inode(inode)->li_transaction);
-		//logfs_inode(inode)->li_transaction = ta;
-		return;
-	}
-
-	switch (ta->state) {
-	case CREATE_1: /* fall through */
-	case UNLINK_1:
-		BUG_ON(super->s_victim_ino);
-		super->s_victim_ino = ta->ino;
-		break;
-	case CREATE_2: /* fall through */
-	case UNLINK_2:
-		BUG_ON(super->s_victim_ino != ta->ino);
-		super->s_victim_ino = 0;
-		/* transaction ends here - free it */
-		kfree(ta);
-		break;
-	case CROSS_RENAME_1:
-		BUG_ON(super->s_rename_dir);
-		BUG_ON(super->s_rename_pos);
-		super->s_rename_dir = ta->dir;
-		super->s_rename_pos = ta->pos;
-		break;
-	case CROSS_RENAME_2:
-		BUG_ON(super->s_rename_dir != ta->dir);
-		BUG_ON(super->s_rename_pos != ta->pos);
-		super->s_rename_dir = 0;
-		super->s_rename_pos = 0;
-		kfree(ta);
-		break;
-	case TARGET_RENAME_1:
-		BUG_ON(super->s_rename_dir);
-		BUG_ON(super->s_rename_pos);
-		BUG_ON(super->s_victim_ino);
-		super->s_rename_dir = ta->dir;
-		super->s_rename_pos = ta->pos;
-		super->s_victim_ino = ta->ino;
-		break;
-	case TARGET_RENAME_2:
-		BUG_ON(super->s_rename_dir != ta->dir);
-		BUG_ON(super->s_rename_pos != ta->pos);
-		BUG_ON(super->s_victim_ino != ta->ino);
-		super->s_rename_dir = 0;
-		super->s_rename_pos = 0;
-		break;
-	case TARGET_RENAME_3:
-		BUG_ON(super->s_rename_dir);
-		BUG_ON(super->s_rename_pos);
-		BUG_ON(super->s_victim_ino != ta->ino);
-		super->s_victim_ino = 0;
-		kfree(ta);
-		break;
-	default:
-		BUG();
-	}
-}
-
-/*
- * Not strictly a reservation, but rather a check that we still have enough
- * space to satisfy the write.
- */
-static int logfs_reserve_blocks(struct inode *inode, int blocks)
-{
-	return logfs_reserve_bytes(inode, blocks * LOGFS_MAX_OBJECTSIZE);
-}
-
-struct write_control {
-	u64 ofs;
-	long flags;
-};
-
-static struct logfs_shadow *alloc_shadow(struct inode *inode, u64 bix,
-		level_t level, u64 old_ofs)
-{
-	struct logfs_super *super = logfs_super(inode->i_sb);
-	struct logfs_shadow *shadow;
-
-	shadow = mempool_alloc(super->s_shadow_pool, GFP_NOFS);
-	memset(shadow, 0, sizeof(*shadow));
-	shadow->ino = inode->i_ino;
-	shadow->bix = bix;
-	shadow->gc_level = expand_level(inode->i_ino, level);
-	shadow->old_ofs = old_ofs & ~LOGFS_FULLY_POPULATED;
-	return shadow;
-}
-
-static void free_shadow(struct inode *inode, struct logfs_shadow *shadow)
-{
-	struct logfs_super *super = logfs_super(inode->i_sb);
-
-	mempool_free(shadow, super->s_shadow_pool);
-}
-
-static void mark_segment(struct shadow_tree *tree, u32 segno)
-{
-	int err;
-
-	if (!btree_lookup32(&tree->segment_map, segno)) {
-		err = btree_insert32(&tree->segment_map, segno, (void *)1,
-				GFP_NOFS);
-		BUG_ON(err);
-		tree->no_shadowed_segments++;
-	}
-}
-
-/**
- * fill_shadow_tree - Propagate shadow tree changes due to a write
- * @inode:	Inode owning the page
- * @page:	Struct page that was written
- * @shadow:	Shadow for the current write
- *
- * Writes in logfs can result in two semi-valid objects.  The old object
- * is still valid as long as it can be reached by following pointers on
- * the medium.  Only when writes propagate all the way up to the journal
- * has the new object safely replaced the old one.
- *
- * To handle this problem, a struct logfs_shadow is used to represent
- * every single write.  It is attached to the indirect block, which is
- * marked dirty.  When the indirect block is written, its shadows are
- * handed up to the next indirect block (or inode).  Untimately they
- * will reach the master inode and be freed upon journal commit.
- *
- * This function handles a single step in the propagation.  It adds the
- * shadow for the current write to the tree, along with any shadows in
- * the page's tree, in case it was an indirect block.  If a page is
- * written, the inode parameter is left NULL, if an inode is written,
- * the page parameter is left NULL.
- */
-static void fill_shadow_tree(struct inode *inode, struct page *page,
-		struct logfs_shadow *shadow)
-{
-	struct logfs_super *super = logfs_super(inode->i_sb);
-	struct logfs_block *block = logfs_block(page);
-	struct shadow_tree *tree = &super->s_shadow_tree;
-
-	if (PagePrivate(page)) {
-		if (block->alias_map)
-			super->s_no_object_aliases -= bitmap_weight(
-					block->alias_map, LOGFS_BLOCK_FACTOR);
-		logfs_handle_transaction(inode, block->ta);
-		block->ops->free_block(inode->i_sb, block);
-	}
-	if (shadow) {
-		if (shadow->old_ofs)
-			btree_insert64(&tree->old, shadow->old_ofs, shadow,
-					GFP_NOFS);
-		else
-			btree_insert64(&tree->new, shadow->new_ofs, shadow,
-					GFP_NOFS);
-
-		super->s_dirty_used_bytes += shadow->new_len;
-		super->s_dirty_free_bytes += shadow->old_len;
-		mark_segment(tree, shadow->old_ofs >> super->s_segshift);
-		mark_segment(tree, shadow->new_ofs >> super->s_segshift);
-	}
-}
-
-static void logfs_set_alias(struct super_block *sb, struct logfs_block *block,
-		long child_no)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	if (block->inode && block->inode->i_ino == LOGFS_INO_MASTER) {
-		/* Aliases in the master inode are pointless. */
-		return;
-	}
-
-	if (!test_bit(child_no, block->alias_map)) {
-		set_bit(child_no, block->alias_map);
-		super->s_no_object_aliases++;
-	}
-	list_move_tail(&block->alias_list, &super->s_object_alias);
-}
-
-/*
- * Object aliases can and often do change the size and occupied space of a
- * file.  So not only do we have to change the pointers, we also have to
- * change inode->i_size and li->li_used_bytes.  Which is done by setting
- * another two object aliases for the inode itself.
- */
-static void set_iused(struct inode *inode, struct logfs_shadow *shadow)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-
-	if (shadow->new_len == shadow->old_len)
-		return;
-
-	alloc_inode_block(inode);
-	li->li_used_bytes += shadow->new_len - shadow->old_len;
-	__logfs_set_blocks(inode);
-	logfs_set_alias(inode->i_sb, li->li_block, INODE_USED_OFS);
-	logfs_set_alias(inode->i_sb, li->li_block, INODE_SIZE_OFS);
-}
-
-static int logfs_write_i0(struct inode *inode, struct page *page,
-		struct write_control *wc)
-{
-	struct logfs_shadow *shadow;
-	u64 bix;
-	level_t level;
-	int full, err = 0;
-
-	logfs_unpack_index(page->index, &bix, &level);
-	if (wc->ofs == 0)
-		if (logfs_reserve_blocks(inode, 1))
-			return -ENOSPC;
-
-	shadow = alloc_shadow(inode, bix, level, wc->ofs);
-	if (wc->flags & WF_WRITE)
-		err = logfs_segment_write(inode, page, shadow);
-	if (wc->flags & WF_DELETE)
-		logfs_segment_delete(inode, shadow);
-	if (err) {
-		free_shadow(inode, shadow);
-		return err;
-	}
-
-	set_iused(inode, shadow);
-	full = 1;
-	if (level != 0) {
-		alloc_indirect_block(inode, page, 0);
-		full = logfs_block(page)->full == LOGFS_BLOCK_FACTOR;
-	}
-	fill_shadow_tree(inode, page, shadow);
-	wc->ofs = shadow->new_ofs;
-	if (wc->ofs && full)
-		wc->ofs |= LOGFS_FULLY_POPULATED;
-	return 0;
-}
-
-static int logfs_write_direct(struct inode *inode, struct page *page,
-		long flags)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	struct write_control wc = {
-		.ofs = li->li_data[page->index],
-		.flags = flags,
-	};
-	int err;
-
-	alloc_inode_block(inode);
-
-	err = logfs_write_i0(inode, page, &wc);
-	if (err)
-		return err;
-
-	li->li_data[page->index] = wc.ofs;
-	logfs_set_alias(inode->i_sb, li->li_block,
-			page->index + INODE_POINTER_OFS);
-	return 0;
-}
-
-static int ptr_change(u64 ofs, struct page *page)
-{
-	struct logfs_block *block = logfs_block(page);
-	int empty0, empty1, full0, full1;
-
-	empty0 = ofs == 0;
-	empty1 = block->partial == 0;
-	if (empty0 != empty1)
-		return 1;
-
-	/* The !! is necessary to shrink result to int */
-	full0 = !!(ofs & LOGFS_FULLY_POPULATED);
-	full1 = block->full == LOGFS_BLOCK_FACTOR;
-	if (full0 != full1)
-		return 1;
-	return 0;
-}
-
-static int __logfs_write_rec(struct inode *inode, struct page *page,
-		struct write_control *this_wc,
-		pgoff_t bix, level_t target_level, level_t level)
-{
-	int ret, page_empty = 0;
-	int child_no = get_bits(bix, SUBLEVEL(level));
-	struct page *ipage;
-	struct write_control child_wc = {
-		.flags = this_wc->flags,
-	};
-
-	ipage = logfs_get_write_page(inode, bix, level);
-	if (!ipage)
-		return -ENOMEM;
-
-	if (this_wc->ofs) {
-		ret = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level);
-		if (ret)
-			goto out;
-	} else if (!PageUptodate(ipage)) {
-		page_empty = 1;
-		logfs_read_empty(ipage);
-	}
-
-	child_wc.ofs = block_get_pointer(ipage, child_no);
-
-	if ((__force u8)level-1 > (__force u8)target_level)
-		ret = __logfs_write_rec(inode, page, &child_wc, bix,
-				target_level, SUBLEVEL(level));
-	else
-		ret = logfs_write_i0(inode, page, &child_wc);
-
-	if (ret)
-		goto out;
-
-	alloc_indirect_block(inode, ipage, page_empty);
-	block_set_pointer(ipage, child_no, child_wc.ofs);
-	/* FIXME: first condition seems superfluous */
-	if (child_wc.ofs || logfs_block(ipage)->partial)
-		this_wc->flags |= WF_WRITE;
-	/* the condition on this_wc->ofs ensures that we won't consume extra
-	 * space for indirect blocks in the future, which we cannot reserve */
-	if (!this_wc->ofs || ptr_change(this_wc->ofs, ipage))
-		ret = logfs_write_i0(inode, ipage, this_wc);
-	else
-		logfs_set_alias(inode->i_sb, logfs_block(ipage), child_no);
-out:
-	logfs_put_write_page(ipage);
-	return ret;
-}
-
-static int logfs_write_rec(struct inode *inode, struct page *page,
-		pgoff_t bix, level_t target_level, long flags)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	struct write_control wc = {
-		.ofs = li->li_data[INDIRECT_INDEX],
-		.flags = flags,
-	};
-	int ret;
-
-	alloc_inode_block(inode);
-
-	if (li->li_height > (__force u8)target_level)
-		ret = __logfs_write_rec(inode, page, &wc, bix, target_level,
-				LEVEL(li->li_height));
-	else
-		ret = logfs_write_i0(inode, page, &wc);
-	if (ret)
-		return ret;
-
-	if (li->li_data[INDIRECT_INDEX] != wc.ofs) {
-		li->li_data[INDIRECT_INDEX] = wc.ofs;
-		logfs_set_alias(inode->i_sb, li->li_block,
-				INDIRECT_INDEX + INODE_POINTER_OFS);
-	}
-	return ret;
-}
-
-void logfs_add_transaction(struct inode *inode, struct logfs_transaction *ta)
-{
-	alloc_inode_block(inode);
-	logfs_inode(inode)->li_block->ta = ta;
-}
-
-void logfs_del_transaction(struct inode *inode, struct logfs_transaction *ta)
-{
-	struct logfs_block *block = logfs_inode(inode)->li_block;
-
-	if (block && block->ta)
-		block->ta = NULL;
-}
-
-static int grow_inode(struct inode *inode, u64 bix, level_t level)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	u8 height = (__force u8)level;
-	struct page *page;
-	struct write_control wc = {
-		.flags = WF_WRITE,
-	};
-	int err;
-
-	BUG_ON(height > 5 || li->li_height > 5);
-	while (height > li->li_height || bix >= maxbix(li->li_height)) {
-		page = logfs_get_write_page(inode, I0_BLOCKS + 1,
-				LEVEL(li->li_height + 1));
-		if (!page)
-			return -ENOMEM;
-		logfs_read_empty(page);
-		alloc_indirect_block(inode, page, 1);
-		block_set_pointer(page, 0, li->li_data[INDIRECT_INDEX]);
-		err = logfs_write_i0(inode, page, &wc);
-		logfs_put_write_page(page);
-		if (err)
-			return err;
-		li->li_data[INDIRECT_INDEX] = wc.ofs;
-		wc.ofs = 0;
-		li->li_height++;
-		logfs_set_alias(inode->i_sb, li->li_block, INODE_HEIGHT_OFS);
-	}
-	return 0;
-}
-
-static int __logfs_write_buf(struct inode *inode, struct page *page, long flags)
-{
-	struct logfs_super *super = logfs_super(inode->i_sb);
-	pgoff_t index = page->index;
-	u64 bix;
-	level_t level;
-	int err;
-
-	flags |= WF_WRITE | WF_DELETE;
-	inode->i_ctime = inode->i_mtime = current_time(inode);
-
-	logfs_unpack_index(index, &bix, &level);
-	if (logfs_block(page) && logfs_block(page)->reserved_bytes)
-		super->s_dirty_pages -= logfs_block(page)->reserved_bytes;
-
-	if (index < I0_BLOCKS)
-		return logfs_write_direct(inode, page, flags);
-
-	bix = adjust_bix(bix, level);
-	err = grow_inode(inode, bix, level);
-	if (err)
-		return err;
-	return logfs_write_rec(inode, page, bix, level, flags);
-}
-
-int logfs_write_buf(struct inode *inode, struct page *page, long flags)
-{
-	struct super_block *sb = inode->i_sb;
-	int ret;
-
-	logfs_get_wblocks(sb, page, flags & WF_LOCK);
-	ret = __logfs_write_buf(inode, page, flags);
-	logfs_put_wblocks(sb, page, flags & WF_LOCK);
-	return ret;
-}
-
-static int __logfs_delete(struct inode *inode, struct page *page)
-{
-	long flags = WF_DELETE;
-	int err;
-
-	inode->i_ctime = inode->i_mtime = current_time(inode);
-
-	if (page->index < I0_BLOCKS)
-		return logfs_write_direct(inode, page, flags);
-	err = grow_inode(inode, page->index, 0);
-	if (err)
-		return err;
-	return logfs_write_rec(inode, page, page->index, 0, flags);
-}
-
-int logfs_delete(struct inode *inode, pgoff_t index,
-		struct shadow_tree *shadow_tree)
-{
-	struct super_block *sb = inode->i_sb;
-	struct page *page;
-	int ret;
-
-	page = logfs_get_read_page(inode, index, 0);
-	if (!page)
-		return -ENOMEM;
-
-	logfs_get_wblocks(sb, page, 1);
-	ret = __logfs_delete(inode, page);
-	logfs_put_wblocks(sb, page, 1);
-
-	logfs_put_read_page(page);
-
-	return ret;
-}
-
-int logfs_rewrite_block(struct inode *inode, u64 bix, u64 ofs,
-		gc_level_t gc_level, long flags)
-{
-	level_t level = shrink_level(gc_level);
-	struct page *page;
-	int err;
-
-	page = logfs_get_write_page(inode, bix, level);
-	if (!page)
-		return -ENOMEM;
-
-	err = logfs_segment_read(inode, page, ofs, bix, level);
-	if (!err) {
-		if (level != 0)
-			alloc_indirect_block(inode, page, 0);
-		err = logfs_write_buf(inode, page, flags);
-		if (!err && shrink_level(gc_level) == 0) {
-			/* Rewrite cannot mark the inode dirty but has to
-			 * write it immediately.
-			 * Q: Can't we just create an alias for the inode
-			 * instead?  And if not, why not?
-			 */
-			if (inode->i_ino == LOGFS_INO_MASTER)
-				logfs_write_anchor(inode->i_sb);
-			else {
-				err = __logfs_write_inode(inode, page, flags);
-			}
-		}
-	}
-	logfs_put_write_page(page);
-	return err;
-}
-
-static int truncate_data_block(struct inode *inode, struct page *page,
-		u64 ofs, struct logfs_shadow *shadow, u64 size)
-{
-	loff_t pageofs = page->index << inode->i_sb->s_blocksize_bits;
-	u64 bix;
-	level_t level;
-	int err;
-
-	/* Does truncation happen within this page? */
-	if (size <= pageofs || size - pageofs >= PAGE_SIZE)
-		return 0;
-
-	logfs_unpack_index(page->index, &bix, &level);
-	BUG_ON(level != 0);
-
-	err = logfs_segment_read(inode, page, ofs, bix, level);
-	if (err)
-		return err;
-
-	zero_user_segment(page, size - pageofs, PAGE_SIZE);
-	return logfs_segment_write(inode, page, shadow);
-}
-
-static int logfs_truncate_i0(struct inode *inode, struct page *page,
-		struct write_control *wc, u64 size)
-{
-	struct logfs_shadow *shadow;
-	u64 bix;
-	level_t level;
-	int err = 0;
-
-	logfs_unpack_index(page->index, &bix, &level);
-	BUG_ON(level != 0);
-	shadow = alloc_shadow(inode, bix, level, wc->ofs);
-
-	err = truncate_data_block(inode, page, wc->ofs, shadow, size);
-	if (err) {
-		free_shadow(inode, shadow);
-		return err;
-	}
-
-	logfs_segment_delete(inode, shadow);
-	set_iused(inode, shadow);
-	fill_shadow_tree(inode, page, shadow);
-	wc->ofs = shadow->new_ofs;
-	return 0;
-}
-
-static int logfs_truncate_direct(struct inode *inode, u64 size)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	struct write_control wc;
-	struct page *page;
-	int e;
-	int err;
-
-	alloc_inode_block(inode);
-
-	for (e = I0_BLOCKS - 1; e >= 0; e--) {
-		if (size > (e+1) * LOGFS_BLOCKSIZE)
-			break;
-
-		wc.ofs = li->li_data[e];
-		if (!wc.ofs)
-			continue;
-
-		page = logfs_get_write_page(inode, e, 0);
-		if (!page)
-			return -ENOMEM;
-		err = logfs_segment_read(inode, page, wc.ofs, e, 0);
-		if (err) {
-			logfs_put_write_page(page);
-			return err;
-		}
-		err = logfs_truncate_i0(inode, page, &wc, size);
-		logfs_put_write_page(page);
-		if (err)
-			return err;
-
-		li->li_data[e] = wc.ofs;
-	}
-	return 0;
-}
-
-/* FIXME: these need to become per-sb once we support different blocksizes */
-static u64 __logfs_step[] = {
-	1,
-	I1_BLOCKS,
-	I2_BLOCKS,
-	I3_BLOCKS,
-};
-
-static u64 __logfs_start_index[] = {
-	I0_BLOCKS,
-	I1_BLOCKS,
-	I2_BLOCKS,
-	I3_BLOCKS
-};
-
-static inline u64 logfs_step(level_t level)
-{
-	return __logfs_step[(__force u8)level];
-}
-
-static inline u64 logfs_factor(u8 level)
-{
-	return __logfs_step[level] * LOGFS_BLOCKSIZE;
-}
-
-static inline u64 logfs_start_index(level_t level)
-{
-	return __logfs_start_index[(__force u8)level];
-}
-
-static void logfs_unpack_raw_index(pgoff_t index, u64 *bix, level_t *level)
-{
-	logfs_unpack_index(index, bix, level);
-	if (*bix <= logfs_start_index(SUBLEVEL(*level)))
-		*bix = 0;
-}
-
-static int __logfs_truncate_rec(struct inode *inode, struct page *ipage,
-		struct write_control *this_wc, u64 size)
-{
-	int truncate_happened = 0;
-	int e, err = 0;
-	u64 bix, child_bix, next_bix;
-	level_t level;
-	struct page *page;
-	struct write_control child_wc = { /* FIXME: flags */ };
-
-	logfs_unpack_raw_index(ipage->index, &bix, &level);
-	err = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level);
-	if (err)
-		return err;
-
-	for (e = LOGFS_BLOCK_FACTOR - 1; e >= 0; e--) {
-		child_bix = bix + e * logfs_step(SUBLEVEL(level));
-		next_bix = child_bix + logfs_step(SUBLEVEL(level));
-		if (size > next_bix * LOGFS_BLOCKSIZE)
-			break;
-
-		child_wc.ofs = pure_ofs(block_get_pointer(ipage, e));
-		if (!child_wc.ofs)
-			continue;
-
-		page = logfs_get_write_page(inode, child_bix, SUBLEVEL(level));
-		if (!page)
-			return -ENOMEM;
-
-		if ((__force u8)level > 1)
-			err = __logfs_truncate_rec(inode, page, &child_wc, size);
-		else
-			err = logfs_truncate_i0(inode, page, &child_wc, size);
-		logfs_put_write_page(page);
-		if (err)
-			return err;
-
-		truncate_happened = 1;
-		alloc_indirect_block(inode, ipage, 0);
-		block_set_pointer(ipage, e, child_wc.ofs);
-	}
-
-	if (!truncate_happened) {
-		printk("ineffectual truncate (%lx, %lx, %llx)\n", inode->i_ino, ipage->index, size);
-		return 0;
-	}
-
-	this_wc->flags = WF_DELETE;
-	if (logfs_block(ipage)->partial)
-		this_wc->flags |= WF_WRITE;
-
-	return logfs_write_i0(inode, ipage, this_wc);
-}
-
-static int logfs_truncate_rec(struct inode *inode, u64 size)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	struct write_control wc = {
-		.ofs = li->li_data[INDIRECT_INDEX],
-	};
-	struct page *page;
-	int err;
-
-	alloc_inode_block(inode);
-
-	if (!wc.ofs)
-		return 0;
-
-	page = logfs_get_write_page(inode, 0, LEVEL(li->li_height));
-	if (!page)
-		return -ENOMEM;
-
-	err = __logfs_truncate_rec(inode, page, &wc, size);
-	logfs_put_write_page(page);
-	if (err)
-		return err;
-
-	if (li->li_data[INDIRECT_INDEX] != wc.ofs)
-		li->li_data[INDIRECT_INDEX] = wc.ofs;
-	return 0;
-}
-
-static int __logfs_truncate(struct inode *inode, u64 size)
-{
-	int ret;
-
-	if (size >= logfs_factor(logfs_inode(inode)->li_height))
-		return 0;
-
-	ret = logfs_truncate_rec(inode, size);
-	if (ret)
-		return ret;
-
-	return logfs_truncate_direct(inode, size);
-}
-
-/*
- * Truncate, by changing the segment file, can consume a fair amount
- * of resources.  So back off from time to time and do some GC.
- * 8 or 2048 blocks should be well within safety limits even if
- * every single block resided in a different segment.
- */
-#define TRUNCATE_STEP	(8 * 1024 * 1024)
-int logfs_truncate(struct inode *inode, u64 target)
-{
-	struct super_block *sb = inode->i_sb;
-	u64 size = i_size_read(inode);
-	int err = 0;
-
-	size = ALIGN(size, TRUNCATE_STEP);
-	while (size > target) {
-		if (size > TRUNCATE_STEP)
-			size -= TRUNCATE_STEP;
-		else
-			size = 0;
-		if (size < target)
-			size = target;
-
-		logfs_get_wblocks(sb, NULL, 1);
-		err = __logfs_truncate(inode, size);
-		if (!err)
-			err = __logfs_write_inode(inode, NULL, 0);
-		logfs_put_wblocks(sb, NULL, 1);
-	}
-
-	if (!err) {
-		err = inode_newsize_ok(inode, target);
-		if (err)
-			goto out;
-
-		truncate_setsize(inode, target);
-	}
-
- out:
-	/* I don't trust error recovery yet. */
-	WARN_ON(err);
-	return err;
-}
-
-static void move_page_to_inode(struct inode *inode, struct page *page)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	struct logfs_block *block = logfs_block(page);
-
-	if (!block)
-		return;
-
-	log_blockmove("move_page_to_inode(%llx, %llx, %x)\n",
-			block->ino, block->bix, block->level);
-	BUG_ON(li->li_block);
-	block->ops = &inode_block_ops;
-	block->inode = inode;
-	li->li_block = block;
-
-	block->page = NULL;
-	if (PagePrivate(page)) {
-		ClearPagePrivate(page);
-		put_page(page);
-		set_page_private(page, 0);
-	}
-}
-
-static void move_inode_to_page(struct page *page, struct inode *inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	struct logfs_block *block = li->li_block;
-
-	if (!block)
-		return;
-
-	log_blockmove("move_inode_to_page(%llx, %llx, %x)\n",
-			block->ino, block->bix, block->level);
-	BUG_ON(PagePrivate(page));
-	block->ops = &indirect_block_ops;
-	block->page = page;
-
-	if (!PagePrivate(page)) {
-		SetPagePrivate(page);
-		get_page(page);
-		set_page_private(page, (unsigned long) block);
-	}
-
-	block->inode = NULL;
-	li->li_block = NULL;
-}
-
-int logfs_read_inode(struct inode *inode)
-{
-	struct super_block *sb = inode->i_sb;
-	struct logfs_super *super = logfs_super(sb);
-	struct inode *master_inode = super->s_master_inode;
-	struct page *page;
-	struct logfs_disk_inode *di;
-	u64 ino = inode->i_ino;
-
-	if (ino << sb->s_blocksize_bits > i_size_read(master_inode))
-		return -ENODATA;
-	if (!logfs_exist_block(master_inode, ino))
-		return -ENODATA;
-
-	page = read_cache_page(master_inode->i_mapping, ino,
-			(filler_t *)logfs_readpage, NULL);
-	if (IS_ERR(page))
-		return PTR_ERR(page);
-
-	di = kmap_atomic(page);
-	logfs_disk_to_inode(di, inode);
-	kunmap_atomic(di);
-	move_page_to_inode(inode, page);
-	put_page(page);
-	return 0;
-}
-
-/* Caller must logfs_put_write_page(page); */
-static struct page *inode_to_page(struct inode *inode)
-{
-	struct inode *master_inode = logfs_super(inode->i_sb)->s_master_inode;
-	struct logfs_disk_inode *di;
-	struct page *page;
-
-	BUG_ON(inode->i_ino == LOGFS_INO_MASTER);
-
-	page = logfs_get_write_page(master_inode, inode->i_ino, 0);
-	if (!page)
-		return NULL;
-
-	di = kmap_atomic(page);
-	logfs_inode_to_disk(inode, di);
-	kunmap_atomic(di);
-	move_inode_to_page(page, inode);
-	return page;
-}
-
-static int do_write_inode(struct inode *inode)
-{
-	struct super_block *sb = inode->i_sb;
-	struct inode *master_inode = logfs_super(sb)->s_master_inode;
-	loff_t size = (inode->i_ino + 1) << inode->i_sb->s_blocksize_bits;
-	struct page *page;
-	int err;
-
-	BUG_ON(inode->i_ino == LOGFS_INO_MASTER);
-	/* FIXME: lock inode */
-
-	if (i_size_read(master_inode) < size)
-		i_size_write(master_inode, size);
-
-	/* TODO: Tell vfs this inode is clean now */
-
-	page = inode_to_page(inode);
-	if (!page)
-		return -ENOMEM;
-
-	/* FIXME: transaction is part of logfs_block now.  Is that enough? */
-	err = logfs_write_buf(master_inode, page, 0);
-	if (err)
-		move_page_to_inode(inode, page);
-
-	logfs_put_write_page(page);
-	return err;
-}
-
-static void logfs_mod_segment_entry(struct super_block *sb, u32 segno,
-		int write,
-		void (*change_se)(struct logfs_segment_entry *, long),
-		long arg)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct inode *inode;
-	struct page *page;
-	struct logfs_segment_entry *se;
-	pgoff_t page_no;
-	int child_no;
-
-	page_no = segno >> (sb->s_blocksize_bits - 3);
-	child_no = segno & ((sb->s_blocksize >> 3) - 1);
-
-	inode = super->s_segfile_inode;
-	page = logfs_get_write_page(inode, page_no, 0);
-	BUG_ON(!page); /* FIXME: We need some reserve page for this case */
-	if (!PageUptodate(page))
-		logfs_read_block(inode, page, WRITE);
-
-	if (write)
-		alloc_indirect_block(inode, page, 0);
-	se = kmap_atomic(page);
-	change_se(se + child_no, arg);
-	if (write) {
-		logfs_set_alias(sb, logfs_block(page), child_no);
-		BUG_ON((int)be32_to_cpu(se[child_no].valid) > super->s_segsize);
-	}
-	kunmap_atomic(se);
-
-	logfs_put_write_page(page);
-}
-
-static void __get_segment_entry(struct logfs_segment_entry *se, long _target)
-{
-	struct logfs_segment_entry *target = (void *)_target;
-
-	*target = *se;
-}
-
-void logfs_get_segment_entry(struct super_block *sb, u32 segno,
-		struct logfs_segment_entry *se)
-{
-	logfs_mod_segment_entry(sb, segno, 0, __get_segment_entry, (long)se);
-}
-
-static void __set_segment_used(struct logfs_segment_entry *se, long increment)
-{
-	u32 valid;
-
-	valid = be32_to_cpu(se->valid);
-	valid += increment;
-	se->valid = cpu_to_be32(valid);
-}
-
-void logfs_set_segment_used(struct super_block *sb, u64 ofs, int increment)
-{
-	struct logfs_super *super = logfs_super(sb);
-	u32 segno = ofs >> super->s_segshift;
-
-	if (!increment)
-		return;
-
-	logfs_mod_segment_entry(sb, segno, 1, __set_segment_used, increment);
-}
-
-static void __set_segment_erased(struct logfs_segment_entry *se, long ec_level)
-{
-	se->ec_level = cpu_to_be32(ec_level);
-}
-
-void logfs_set_segment_erased(struct super_block *sb, u32 segno, u32 ec,
-		gc_level_t gc_level)
-{
-	u32 ec_level = ec << 4 | (__force u8)gc_level;
-
-	logfs_mod_segment_entry(sb, segno, 1, __set_segment_erased, ec_level);
-}
-
-static void __set_segment_reserved(struct logfs_segment_entry *se, long ignore)
-{
-	se->valid = cpu_to_be32(RESERVED);
-}
-
-void logfs_set_segment_reserved(struct super_block *sb, u32 segno)
-{
-	logfs_mod_segment_entry(sb, segno, 1, __set_segment_reserved, 0);
-}
-
-static void __set_segment_unreserved(struct logfs_segment_entry *se,
-		long ec_level)
-{
-	se->valid = 0;
-	se->ec_level = cpu_to_be32(ec_level);
-}
-
-void logfs_set_segment_unreserved(struct super_block *sb, u32 segno, u32 ec)
-{
-	u32 ec_level = ec << 4;
-
-	logfs_mod_segment_entry(sb, segno, 1, __set_segment_unreserved,
-			ec_level);
-}
-
-int __logfs_write_inode(struct inode *inode, struct page *page, long flags)
-{
-	struct super_block *sb = inode->i_sb;
-	int ret;
-
-	logfs_get_wblocks(sb, page, flags & WF_LOCK);
-	ret = do_write_inode(inode);
-	logfs_put_wblocks(sb, page, flags & WF_LOCK);
-	return ret;
-}
-
-static int do_delete_inode(struct inode *inode)
-{
-	struct super_block *sb = inode->i_sb;
-	struct inode *master_inode = logfs_super(sb)->s_master_inode;
-	struct page *page;
-	int ret;
-
-	page = logfs_get_write_page(master_inode, inode->i_ino, 0);
-	if (!page)
-		return -ENOMEM;
-
-	move_inode_to_page(page, inode);
-
-	logfs_get_wblocks(sb, page, 1);
-	ret = __logfs_delete(master_inode, page);
-	logfs_put_wblocks(sb, page, 1);
-
-	logfs_put_write_page(page);
-	return ret;
-}
-
-/*
- * ZOMBIE inodes have already been deleted before and should remain dead,
- * if it weren't for valid checking.  No need to kill them again here.
- */
-void logfs_evict_inode(struct inode *inode)
-{
-	struct super_block *sb = inode->i_sb;
-	struct logfs_inode *li = logfs_inode(inode);
-	struct logfs_block *block = li->li_block;
-	struct page *page;
-
-	if (!inode->i_nlink) {
-		if (!(li->li_flags & LOGFS_IF_ZOMBIE)) {
-			li->li_flags |= LOGFS_IF_ZOMBIE;
-			if (i_size_read(inode) > 0)
-				logfs_truncate(inode, 0);
-			do_delete_inode(inode);
-		}
-	}
-	truncate_inode_pages_final(&inode->i_data);
-	clear_inode(inode);
-
-	/* Cheaper version of write_inode.  All changes are concealed in
-	 * aliases, which are moved back.  No write to the medium happens.
-	 */
-	/* Only deleted files may be dirty at this point */
-	BUG_ON(inode->i_state & I_DIRTY && inode->i_nlink);
-	if (!block)
-		return;
-	if ((logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN)) {
-		block->ops->free_block(inode->i_sb, block);
-		return;
-	}
-
-	page = inode_to_page(inode);
-	BUG_ON(!page); /* FIXME: Use emergency page */
-	logfs_put_write_page(page);
-}
-
-void btree_write_block(struct logfs_block *block)
-{
-	struct inode *inode;
-	struct page *page;
-	int err, cookie;
-
-	inode = logfs_safe_iget(block->sb, block->ino, &cookie);
-	page = logfs_get_write_page(inode, block->bix, block->level);
-
-	err = logfs_readpage_nolock(page);
-	BUG_ON(err);
-	BUG_ON(!PagePrivate(page));
-	BUG_ON(logfs_block(page) != block);
-	err = __logfs_write_buf(inode, page, 0);
-	BUG_ON(err);
-	BUG_ON(PagePrivate(page) || page->private);
-
-	logfs_put_write_page(page);
-	logfs_safe_iput(inode, cookie);
-}
-
-/**
- * logfs_inode_write - write inode or dentry objects
- *
- * @inode:		parent inode (ifile or directory)
- * @buf:		object to write (inode or dentry)
- * @count:		object size
- * @bix:		block index
- * @flags:		write flags
- * @shadow_tree:	shadow below this inode
- *
- * FIXME: All caller of this put a 200-300 byte variable on the stack,
- * only to call here and do a memcpy from that stack variable.  A good
- * example of wasted performance and stack space.
- */
-int logfs_inode_write(struct inode *inode, const void *buf, size_t count,
-		loff_t bix, long flags, struct shadow_tree *shadow_tree)
-{
-	loff_t pos = bix << inode->i_sb->s_blocksize_bits;
-	int err;
-	struct page *page;
-	void *pagebuf;
-
-	BUG_ON(pos & (LOGFS_BLOCKSIZE-1));
-	BUG_ON(count > LOGFS_BLOCKSIZE);
-	page = logfs_get_write_page(inode, bix, 0);
-	if (!page)
-		return -ENOMEM;
-
-	pagebuf = kmap_atomic(page);
-	memcpy(pagebuf, buf, count);
-	flush_dcache_page(page);
-	kunmap_atomic(pagebuf);
-
-	if (i_size_read(inode) < pos + LOGFS_BLOCKSIZE)
-		i_size_write(inode, pos + LOGFS_BLOCKSIZE);
-
-	err = logfs_write_buf(inode, page, flags);
-	logfs_put_write_page(page);
-	return err;
-}
-
-int logfs_open_segfile(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct inode *inode;
-
-	inode = logfs_read_meta_inode(sb, LOGFS_INO_SEGFILE);
-	if (IS_ERR(inode))
-		return PTR_ERR(inode);
-	super->s_segfile_inode = inode;
-	return 0;
-}
-
-int logfs_init_rw(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int min_fill = 3 * super->s_no_blocks;
-
-	INIT_LIST_HEAD(&super->s_object_alias);
-	INIT_LIST_HEAD(&super->s_writeback_list);
-	mutex_init(&super->s_write_mutex);
-	super->s_block_pool = mempool_create_kmalloc_pool(min_fill,
-			sizeof(struct logfs_block));
-	super->s_shadow_pool = mempool_create_kmalloc_pool(min_fill,
-			sizeof(struct logfs_shadow));
-	return 0;
-}
-
-void logfs_cleanup_rw(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	logfs_mempool_destroy(super->s_block_pool);
-	logfs_mempool_destroy(super->s_shadow_pool);
-}

fs/logfs/segment.c

···
-/*
- * fs/logfs/segment.c	- Handling the Object Store
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- *
- * Object store or ostore makes up the complete device with exception of
- * the superblock and journal areas.  Apart from its own metadata it stores
- * three kinds of objects: inodes, dentries and blocks, both data and indirect.
- */
-#include "logfs.h"
-#include <linux/slab.h>
-
-static int logfs_mark_segment_bad(struct super_block *sb, u32 segno)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct btree_head32 *head = &super->s_reserved_segments;
-	int err;
-
-	err = btree_insert32(head, segno, (void *)1, GFP_NOFS);
-	if (err)
-		return err;
-	logfs_super(sb)->s_bad_segments++;
-	/* FIXME: write to journal */
-	return 0;
-}
-
-int logfs_erase_segment(struct super_block *sb, u32 segno, int ensure_erase)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	super->s_gec++;
-
-	return super->s_devops->erase(sb, (u64)segno << super->s_segshift,
-			super->s_segsize, ensure_erase);
-}
-
-static s64 logfs_get_free_bytes(struct logfs_area *area, size_t bytes)
-{
-	s32 ofs;
-
-	logfs_open_area(area, bytes);
-
-	ofs = area->a_used_bytes;
-	area->a_used_bytes += bytes;
-	BUG_ON(area->a_used_bytes >= logfs_super(area->a_sb)->s_segsize);
-
-	return dev_ofs(area->a_sb, area->a_segno, ofs);
-}
-
-static struct page *get_mapping_page(struct super_block *sb, pgoff_t index,
-		int use_filler)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct address_space *mapping = super->s_mapping_inode->i_mapping;
-	filler_t *filler = super->s_devops->readpage;
-	struct page *page;
-
-	BUG_ON(mapping_gfp_constraint(mapping, __GFP_FS));
-	if (use_filler)
-		page = read_cache_page(mapping, index, filler, sb);
-	else {
-		page = find_or_create_page(mapping, index, GFP_NOFS);
-		if (page)
-			unlock_page(page);
-	}
-	return page;
-}
-
-int __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
-		int use_filler)
-{
-	pgoff_t index = ofs >> PAGE_SHIFT;
-	struct page *page;
-	long offset = ofs & (PAGE_SIZE-1);
-	long copylen;
-
-	/* Only logfs_wbuf_recover may use len==0 */
-	BUG_ON(!len && !use_filler);
-	do {
-		copylen = min((ulong)len, PAGE_SIZE - offset);
-
-		page = get_mapping_page(area->a_sb, index, use_filler);
-		if (IS_ERR(page))
-			return PTR_ERR(page);
-		BUG_ON(!page); /* FIXME: reserve a pool */
-		SetPageUptodate(page);
-		memcpy(page_address(page) + offset, buf, copylen);
-
-		if (!PagePrivate(page)) {
-			SetPagePrivate(page);
-			get_page(page);
-		}
-		put_page(page);
-
-		buf += copylen;
-		len -= copylen;
-		offset = 0;
-		index++;
-	} while (len);
-	return 0;
-}
-
-static void pad_partial_page(struct logfs_area *area)
-{
-	struct super_block *sb = area->a_sb;
-	struct page *page;
-	u64 ofs = dev_ofs(sb, area->a_segno, area->a_used_bytes);
-	pgoff_t index = ofs >> PAGE_SHIFT;
-	long offset = ofs & (PAGE_SIZE-1);
-	u32 len = PAGE_SIZE - offset;
-
-	if (len % PAGE_SIZE) {
-		page = get_mapping_page(sb, index, 0);
-		BUG_ON(!page); /* FIXME: reserve a pool */
-		memset(page_address(page) + offset, 0xff, len);
-		if (!PagePrivate(page)) {
-			SetPagePrivate(page);
-			get_page(page);
-		}
-		put_page(page);
-	}
-}
-
-static void pad_full_pages(struct logfs_area *area)
-{
-	struct super_block *sb = area->a_sb;
-	struct logfs_super *super = logfs_super(sb);
-	u64 ofs = dev_ofs(sb, area->a_segno, area->a_used_bytes);
-	u32 len = super->s_segsize - area->a_used_bytes;
-	pgoff_t index = PAGE_ALIGN(ofs) >> PAGE_SHIFT;
-	pgoff_t no_indizes = len >> PAGE_SHIFT;
-	struct page *page;
-
-	while (no_indizes) {
-		page = get_mapping_page(sb, index, 0);
-		BUG_ON(!page); /* FIXME: reserve a pool */
-		SetPageUptodate(page);
-		memset(page_address(page), 0xff, PAGE_SIZE);
-		if (!PagePrivate(page)) {
-			SetPagePrivate(page);
-			get_page(page);
-		}
-		put_page(page);
-		index++;
-		no_indizes--;
-	}
-}
-
-/*
- * bdev_writeseg will write full pages.  Memset the tail to prevent data leaks.
- * Also make sure we allocate (and memset) all pages for final writeout.
- */
-static void pad_wbuf(struct logfs_area *area, int final)
-{
-	pad_partial_page(area);
-	if (final)
-		pad_full_pages(area);
-}
-
-/*
- * We have to be careful with the alias tree.  Since lookup is done by bix,
- * it needs to be normalized, so 14, 15, 16, etc. all match when dealing with
- * indirect blocks.  So always use it through accessor functions.
- */
-static void *alias_tree_lookup(struct super_block *sb, u64 ino, u64 bix,
-		level_t level)
-{
-	struct btree_head128 *head = &logfs_super(sb)->s_object_alias_tree;
-	pgoff_t index = logfs_pack_index(bix, level);
-
-	return btree_lookup128(head, ino, index);
-}
-
-static int alias_tree_insert(struct super_block *sb, u64 ino, u64 bix,
-		level_t level, void *val)
-{
-	struct btree_head128 *head = &logfs_super(sb)->s_object_alias_tree;
-	pgoff_t index = logfs_pack_index(bix, level);
-
-	return btree_insert128(head, ino, index, val, GFP_NOFS);
-}
-
-static int btree_write_alias(struct super_block *sb, struct logfs_block *block,
-		write_alias_t *write_one_alias)
-{
-	struct object_alias_item *item;
-	int err;
-
-	list_for_each_entry(item, &block->item_list, list) {
-		err = write_alias_journal(sb, block->ino, block->bix,
-				block->level, item->child_no, item->val);
-		if (err)
-			return err;
-	}
-	return 0;
-}
-
-static const struct logfs_block_ops btree_block_ops = {
-	.write_block	= btree_write_block,
-	.free_block	= __free_block,
-	.write_alias	= btree_write_alias,
-};
-
-int logfs_load_object_aliases(struct super_block *sb,
-		struct logfs_obj_alias *oa, int count)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_block *block;
-	struct object_alias_item *item;
-	u64 ino, bix;
-	level_t level;
-	int i, err;
-
-	super->s_flags |= LOGFS_SB_FLAG_OBJ_ALIAS;
-	count /= sizeof(*oa);
-	for (i = 0; i < count; i++) {
-		item = mempool_alloc(super->s_alias_pool, GFP_NOFS);
-		if (!item)
-			return -ENOMEM;
-		memset(item, 0, sizeof(*item));
-
-		super->s_no_object_aliases++;
-		item->val = oa[i].val;
-		item->child_no = be16_to_cpu(oa[i].child_no);
-
-		ino = be64_to_cpu(oa[i].ino);
-		bix = be64_to_cpu(oa[i].bix);
-		level = LEVEL(oa[i].level);
-
-		log_aliases("logfs_load_object_aliases(%llx, %llx, %x, %x) %llx\n",
-				ino, bix, level, item->child_no,
-				be64_to_cpu(item->val));
-		block = alias_tree_lookup(sb, ino, bix, level);
-		if (!block) {
-			block = __alloc_block(sb, ino, bix, level);
-			block->ops = &btree_block_ops;
-			err = alias_tree_insert(sb, ino, bix, level, block);
-			BUG_ON(err); /* mempool empty */
-		}
-		if (test_and_set_bit(item->child_no, block->alias_map)) {
-			printk(KERN_ERR"LogFS: Alias collision detected\n");
-			return -EIO;
-		}
-		list_move_tail(&block->alias_list, &super->s_object_alias);
-		list_add(&item->list, &block->item_list);
-	}
-	return 0;
-}
-
-static void kill_alias(void *_block, unsigned long ignore0,
-		u64 ignore1, u64 ignore2, size_t ignore3)
-{
-	struct logfs_block *block = _block;
-	struct super_block *sb = block->sb;
-	struct logfs_super *super = logfs_super(sb);
-	struct object_alias_item *item;
-
-	while (!list_empty(&block->item_list)) {
-		item = list_entry(block->item_list.next, typeof(*item), list);
-		list_del(&item->list);
-		mempool_free(item, super->s_alias_pool);
-	}
-	block->ops->free_block(sb, block);
-}
-
-static int obj_type(struct inode *inode, level_t level)
-{
-	if (level == 0) {
-		if (S_ISDIR(inode->i_mode))
-			return OBJ_DENTRY;
-		if (inode->i_ino == LOGFS_INO_MASTER)
-			return OBJ_INODE;
-	}
-	return OBJ_BLOCK;
-}
-
-static int obj_len(struct super_block *sb, int obj_type)
-{
-	switch (obj_type) {
-	case OBJ_DENTRY:
-		return sizeof(struct logfs_disk_dentry);
-	case OBJ_INODE:
-		return sizeof(struct logfs_disk_inode);
-	case OBJ_BLOCK:
-		return sb->s_blocksize;
-	default:
-		BUG();
-	}
-}
-
-static int __logfs_segment_write(struct inode *inode, void *buf,
-		struct logfs_shadow *shadow, int type, int len, int compr)
-{
-	struct logfs_area *area;
-	struct super_block *sb = inode->i_sb;
-	s64 ofs;
-	struct logfs_object_header h;
-	int acc_len;
-
-	if (shadow->gc_level == 0)
-		acc_len = len;
-	else
-		acc_len = obj_len(sb, type);
-
-	area = get_area(sb, shadow->gc_level);
-	ofs = logfs_get_free_bytes(area, len + LOGFS_OBJECT_HEADERSIZE);
-	LOGFS_BUG_ON(ofs <= 0, sb);
-	/*
-	 * Order is important.  logfs_get_free_bytes(), by modifying the
-	 * segment file, may modify the content of the very page we're about
-	 * to write now.  Which is fine, as long as the calculated crc and
-	 * written data still match.  So do the modifications _before_
-	 * calculating the crc.
-	 */
-
-	h.len	= cpu_to_be16(len);
-	h.type	= type;
-	h.compr	= compr;
-	h.ino	= cpu_to_be64(inode->i_ino);
-	h.bix	= cpu_to_be64(shadow->bix);
-	h.crc	= logfs_crc32(&h, sizeof(h) - 4, 4);
-	h.data_crc = logfs_crc32(buf, len, 0);
-
-	logfs_buf_write(area, ofs, &h, sizeof(h));
-	logfs_buf_write(area, ofs + LOGFS_OBJECT_HEADERSIZE, buf, len);
-
-	shadow->new_ofs = ofs;
-	shadow->new_len = acc_len + LOGFS_OBJECT_HEADERSIZE;
-
-	return 0;
-}
-
-static s64 logfs_segment_write_compress(struct inode *inode, void *buf,
-		struct logfs_shadow *shadow, int type, int len)
-{
-	struct super_block *sb = inode->i_sb;
-	void *compressor_buf = logfs_super(sb)->s_compressed_je;
-	ssize_t compr_len;
-	int ret;
-
-	mutex_lock(&logfs_super(sb)->s_journal_mutex);
-	compr_len = logfs_compress(buf, compressor_buf, len, len);
-
-	if (compr_len >= 0) {
-		ret = __logfs_segment_write(inode, compressor_buf, shadow,
-				type, compr_len, COMPR_ZLIB);
-	} else {
-		ret = __logfs_segment_write(inode, buf, shadow, type, len,
-				COMPR_NONE);
-	}
-	mutex_unlock(&logfs_super(sb)->s_journal_mutex);
-	return ret;
-}
-
-/**
- * logfs_segment_write - write data block to object store
- * @inode:		inode containing data
- *
- * Returns an errno or zero.
- */
-int logfs_segment_write(struct inode *inode, struct page *page,
-		struct logfs_shadow *shadow)
-{
-	struct super_block *sb = inode->i_sb;
-	struct logfs_super *super = logfs_super(sb);
-	int do_compress, type, len;
-	int ret;
-	void *buf;
-
-	super->s_flags |= LOGFS_SB_FLAG_DIRTY;
-	BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);
-	do_compress = logfs_inode(inode)->li_flags & LOGFS_IF_COMPRESSED;
-	if (shadow->gc_level != 0) {
-		/* temporarily disable compression for indirect blocks */
-		do_compress = 0;
-	}
-
-	type = obj_type(inode, shrink_level(shadow->gc_level));
-	len = obj_len(sb, type);
-	buf = kmap(page);
-	if (do_compress)
-		ret = logfs_segment_write_compress(inode, buf, shadow, type,
-				len);
-	else
-		ret = __logfs_segment_write(inode, buf, shadow, type, len,
-				COMPR_NONE);
-	kunmap(page);
-
-	log_segment("logfs_segment_write(%llx, %llx, %x) %llx->%llx %x->%x\n",
-			shadow->ino, shadow->bix, shadow->gc_level,
-			shadow->old_ofs, shadow->new_ofs,
-			shadow->old_len, shadow->new_len);
-	/* this BUG_ON did catch a locking bug.  useful */
-	BUG_ON(!(shadow->new_ofs & (super->s_segsize - 1)));
-	return ret;
-}
-
-int wbuf_read(struct super_block *sb, u64 ofs, size_t len, void *buf)
-{
-	pgoff_t index = ofs >> PAGE_SHIFT;
-	struct page *page;
-	long offset = ofs & (PAGE_SIZE-1);
-	long copylen;
-
-	while (len) {
-		copylen = min((ulong)len, PAGE_SIZE - offset);
-
-		page = get_mapping_page(sb, index, 1);
-		if (IS_ERR(page))
-			return PTR_ERR(page);
-		memcpy(buf, page_address(page) + offset, copylen);
-		put_page(page);
-
-		buf += copylen;
-		len -= copylen;
-		offset = 0;
-		index++;
-	}
-	return 0;
-}
-
-/*
- * The "position" of indirect blocks is ambiguous.  It can be the position
- * of any data block somewhere behind this indirect block.  So we need to
- * normalize the positions through logfs_block_mask() before comparing.
- */
-static int check_pos(struct super_block *sb, u64 pos1, u64 pos2, level_t level)
-{
-	return	(pos1 & logfs_block_mask(sb, level)) !=
-		(pos2 & logfs_block_mask(sb, level));
-}
-
-#if 0
-static int read_seg_header(struct super_block *sb, u64 ofs,
-		struct logfs_segment_header *sh)
-{
-	__be32 crc;
-	int err;
-
-	err = wbuf_read(sb, ofs, sizeof(*sh), sh);
-	if (err)
-		return err;
-	crc = logfs_crc32(sh, sizeof(*sh), 4);
-	if (crc != sh->crc) {
-		printk(KERN_ERR"LOGFS: header crc error at %llx: expected %x, "
-				"got %x\n", ofs, be32_to_cpu(sh->crc),
-				be32_to_cpu(crc));
-		return -EIO;
-	}
-	return 0;
-}
-#endif
-
-static int read_obj_header(struct super_block *sb, u64 ofs,
-		struct logfs_object_header *oh)
-{
-	__be32 crc;
-	int err;
-
-	err = wbuf_read(sb, ofs, sizeof(*oh), oh);
-	if (err)
-		return err;
-	crc = logfs_crc32(oh, sizeof(*oh) - 4, 4);
-	if (crc != oh->crc) {
-		printk(KERN_ERR"LOGFS: header crc error at %llx: expected %x, "
-				"got %x\n", ofs, be32_to_cpu(oh->crc),
-				be32_to_cpu(crc));
-		return -EIO;
-	}
-	return 0;
-}
-
-static void move_btree_to_page(struct inode *inode, struct page *page,
-		__be64 *data)
-{
-	struct super_block *sb = inode->i_sb;
-	struct logfs_super *super = logfs_super(sb);
-	struct btree_head128 *head = &super->s_object_alias_tree;
-	struct logfs_block *block;
-	struct object_alias_item *item, *next;
-
-	if (!(super->s_flags & LOGFS_SB_FLAG_OBJ_ALIAS))
-		return;
-
-	block = btree_remove128(head, inode->i_ino, page->index);
-	if (!block)
-		return;
-
-	log_blockmove("move_btree_to_page(%llx, %llx, %x)\n",
-			block->ino, block->bix, block->level);
-	list_for_each_entry_safe(item, next, &block->item_list, list) {
-		data[item->child_no] = item->val;
-		list_del(&item->list);
-		mempool_free(item, super->s_alias_pool);
-	}
-	block->page = page;
-
-	if (!PagePrivate(page)) {
-		SetPagePrivate(page);
-		get_page(page);
-		set_page_private(page, (unsigned long) block);
-	}
-	block->ops = &indirect_block_ops;
-	initialize_block_counters(page, block, data, 0);
-}
-
-/*
- * This silences a false, yet annoying gcc warning.  I hate it when my editor
- * jumps into bitops.h each time I recompile this file.
- * TODO: Complain to gcc folks about this and upgrade compiler.
- */
-static unsigned long fnb(const unsigned long *addr,
-		unsigned long size, unsigned long offset)
-{
-	return find_next_bit(addr, size, offset);
-}
-
-void move_page_to_btree(struct page *page)
-{
-	struct logfs_block *block = logfs_block(page);
-	struct super_block *sb = block->sb;
-	struct logfs_super *super = logfs_super(sb);
-	struct object_alias_item *item;
-	unsigned long pos;
-	__be64 *child;
-	int err;
-
-	if (super->s_flags & LOGFS_SB_FLAG_SHUTDOWN) {
-		block->ops->free_block(sb, block);
-		return;
-	}
-	log_blockmove("move_page_to_btree(%llx, %llx, %x)\n",
-			block->ino, block->bix, block->level);
-	super->s_flags |= LOGFS_SB_FLAG_OBJ_ALIAS;
-
-	for (pos = 0; ; pos++) {
-		pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos);
-		if (pos >= LOGFS_BLOCK_FACTOR)
-			break;
-
-		item = mempool_alloc(super->s_alias_pool, GFP_NOFS);
-		BUG_ON(!item); /* mempool empty */
-		memset(item, 0, sizeof(*item));
-
-		child = kmap_atomic(page);
-		item->val = child[pos];
-		kunmap_atomic(child);
-		item->child_no = pos;
-		list_add(&item->list, &block->item_list);
-	}
-	block->page = NULL;
-
-	if (PagePrivate(page)) {
-		ClearPagePrivate(page);
-		put_page(page);
-		set_page_private(page, 0);
-	}
-	block->ops = &btree_block_ops;
-	err = alias_tree_insert(block->sb, block->ino, block->bix, block->level,
-			block);
-	BUG_ON(err); /* mempool empty */
-	ClearPageUptodate(page);
-}
-
-static int __logfs_segment_read(struct inode *inode, void *buf,
-		u64 ofs, u64 bix, level_t level)
-{
-	struct super_block *sb = inode->i_sb;
-	void *compressor_buf = logfs_super(sb)->s_compressed_je;
-	struct logfs_object_header oh;
-	__be32 crc;
-	u16 len;
-	int err, block_len;
-
-	block_len = obj_len(sb, obj_type(inode, level));
-	err = read_obj_header(sb, ofs, &oh);
-	if (err)
-		goto out_err;
-
-	err = -EIO;
-	if (be64_to_cpu(oh.ino) != inode->i_ino
-			|| check_pos(sb, be64_to_cpu(oh.bix), bix, level)) {
-		printk(KERN_ERR"LOGFS: (ino, bix) don't match at %llx: "
-				"expected (%lx, %llx), got (%llx, %llx)\n",
-				ofs, inode->i_ino, bix,
-				be64_to_cpu(oh.ino), be64_to_cpu(oh.bix));
-		goto out_err;
-	}
-
-	len = be16_to_cpu(oh.len);
-
-	switch (oh.compr) {
-	case COMPR_NONE:
-		err = wbuf_read(sb, ofs + LOGFS_OBJECT_HEADERSIZE, len, buf);
-		if (err)
-			goto out_err;
-		crc = logfs_crc32(buf, len, 0);
-		if (crc != oh.data_crc) {
-			printk(KERN_ERR"LOGFS: uncompressed data crc error at "
-					"%llx: expected %x, got %x\n", ofs,
-					be32_to_cpu(oh.data_crc),
-					be32_to_cpu(crc));
-			goto out_err;
-		}
-		break;
-	case COMPR_ZLIB:
-		mutex_lock(&logfs_super(sb)->s_journal_mutex);
-		err = wbuf_read(sb, ofs + LOGFS_OBJECT_HEADERSIZE, len,
-				compressor_buf);
-		if (err) {
-			mutex_unlock(&logfs_super(sb)->s_journal_mutex);
-			goto out_err;
-		}
-		crc = logfs_crc32(compressor_buf, len, 0);
-		if (crc != oh.data_crc) {
-			printk(KERN_ERR"LOGFS: compressed data crc error at "
-					"%llx: expected %x, got %x\n", ofs,
-					be32_to_cpu(oh.data_crc),
-					be32_to_cpu(crc));
-			mutex_unlock(&logfs_super(sb)->s_journal_mutex);
-			goto out_err;
-		}
-		err = logfs_uncompress(compressor_buf, buf, len, block_len);
-		mutex_unlock(&logfs_super(sb)->s_journal_mutex);
-		if (err) {
-			printk(KERN_ERR"LOGFS: uncompress error at %llx\n", ofs);
-			goto out_err;
-		}
-		break;
-	default:
-		LOGFS_BUG(sb);
-		err = -EIO;
-		goto out_err;
-	}
-	return 0;
-
-out_err:
-	logfs_set_ro(sb);
-	printk(KERN_ERR"LOGFS: device is read-only now\n");
-	LOGFS_BUG(sb);
-	return err;
-}
-
-/**
- * logfs_segment_read - read data block from object store
- * @inode:		inode containing data
- * @buf:		data buffer
- * @ofs:		physical data offset
- * @bix:		block index
- * @level:		block level
- *
- * Returns 0 on success or a negative errno.
- */
-int logfs_segment_read(struct inode *inode, struct page *page,
-		u64 ofs, u64 bix, level_t level)
-{
-	int err;
-	void *buf;
-
-	if (PageUptodate(page))
-		return 0;
-
-	ofs &= ~LOGFS_FULLY_POPULATED;
-
-	buf = kmap(page);
-	err = __logfs_segment_read(inode, buf, ofs, bix, level);
-	if (!err) {
-		move_btree_to_page(inode, page, buf);
-		SetPageUptodate(page);
-	}
-	kunmap(page);
-	log_segment("logfs_segment_read(%lx, %llx, %x) %llx (%d)\n",
-			inode->i_ino, bix, level, ofs, err);
-	return err;
-}
-
-int logfs_segment_delete(struct inode *inode, struct logfs_shadow *shadow)
-{
-	struct super_block *sb = inode->i_sb;
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_object_header h;
-	u16 len;
-	int err;
-
-	super->s_flags |= LOGFS_SB_FLAG_DIRTY;
-	BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);
-	BUG_ON(shadow->old_ofs & LOGFS_FULLY_POPULATED);
-	if (!shadow->old_ofs)
-		return 0;
-
-	log_segment("logfs_segment_delete(%llx, %llx, %x) %llx->%llx %x->%x\n",
-			shadow->ino, shadow->bix, shadow->gc_level,
-			shadow->old_ofs, shadow->new_ofs,
-			shadow->old_len, shadow->new_len);
-	err = read_obj_header(sb, shadow->old_ofs, &h);
-	LOGFS_BUG_ON(err, sb);
-	LOGFS_BUG_ON(be64_to_cpu(h.ino) != inode->i_ino, sb);
-	LOGFS_BUG_ON(check_pos(sb, shadow->bix, be64_to_cpu(h.bix),
-				shrink_level(shadow->gc_level)), sb);
-
-	if (shadow->gc_level == 0)
-		len = be16_to_cpu(h.len);
-	else
-		len = obj_len(sb, h.type);
-	shadow->old_len = len + sizeof(h);
-	return 0;
-}
-
-void freeseg(struct super_block *sb, u32 segno)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct address_space *mapping = super->s_mapping_inode->i_mapping;
-	struct page *page;
-	u64 ofs, start, end;
-
-	start = dev_ofs(sb, segno, 0);
-	end = dev_ofs(sb, segno + 1, 0);
-	for (ofs = start; ofs < end; ofs += PAGE_SIZE) {
-		page = find_get_page(mapping, ofs >> PAGE_SHIFT);
-		if (!page)
-			continue;
-		if (PagePrivate(page)) {
-			ClearPagePrivate(page);
-			put_page(page);
-		}
-		put_page(page);
-	}
-}
-
-int logfs_open_area(struct logfs_area *area, size_t bytes)
-{
-	struct super_block *sb = area->a_sb;
-	struct logfs_super *super = logfs_super(sb);
-	int err, closed = 0;
-
-	if (area->a_is_open && area->a_used_bytes + bytes <= super->s_segsize)
-		return 0;
-
-	if (area->a_is_open) {
-		u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
-		u32 len = super->s_segsize - area->a_written_bytes;
-
-		log_gc("logfs_close_area(%x)\n", area->a_segno);
-		pad_wbuf(area, 1);
-		super->s_devops->writeseg(area->a_sb, ofs, len);
-		freeseg(sb, area->a_segno);
-		closed = 1;
-	}
-
-	area->a_used_bytes = 0;
-	area->a_written_bytes = 0;
-again:
-	area->a_ops->get_free_segment(area);
-	area->a_ops->get_erase_count(area);
-
-	log_gc("logfs_open_area(%x, %x)\n", area->a_segno, area->a_level);
-	err = area->a_ops->erase_segment(area);
-	if (err) {
-		printk(KERN_WARNING "LogFS: Error erasing segment %x\n",
-				area->a_segno);
-		logfs_mark_segment_bad(sb, area->a_segno);
-		goto again;
-	}
-	area->a_is_open = 1;
-	return closed;
-}
-
-void logfs_sync_area(struct logfs_area *area)
-{
-	struct super_block *sb = area->a_sb;
-	struct logfs_super *super = logfs_super(sb);
-	u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
-	u32 len = (area->a_used_bytes - area->a_written_bytes);
-
-	if (super->s_writesize)
-		len &= ~(super->s_writesize - 1);
-	if (len == 0)
-		return;
-	pad_wbuf(area, 0);
-	super->s_devops->writeseg(sb, ofs, len);
-	area->a_written_bytes += len;
-}
-
-void logfs_sync_segments(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int i;
-
-	for_each_area(i)
-		logfs_sync_area(super->s_area[i]);
-}
-
-/*
- * Pick a free segment to be used for this area.  Effectively takes a
- * candidate from the free list (not really a candidate anymore).
- */
-static void ostore_get_free_segment(struct logfs_area *area)
-{
-	struct super_block *sb = area->a_sb;
-	struct logfs_super *super = logfs_super(sb);
-
-	if (super->s_free_list.count == 0) {
-		printk(KERN_ERR"LOGFS: ran out of free segments\n");
-		LOGFS_BUG(sb);
-	}
-
-	area->a_segno = get_best_cand(sb, &super->s_free_list, NULL);
-}
-
-static void ostore_get_erase_count(struct logfs_area *area)
-{
-	struct logfs_segment_entry se;
-	u32 ec_level;
-
-	logfs_get_segment_entry(area->a_sb, area->a_segno, &se);
-	BUG_ON(se.ec_level == cpu_to_be32(BADSEG) ||
-			se.valid == cpu_to_be32(RESERVED));
-
-	ec_level = be32_to_cpu(se.ec_level);
-	area->a_erase_count = (ec_level >> 4) + 1;
-}
-
-static int ostore_erase_segment(struct logfs_area *area)
-{
-	struct super_block *sb = area->a_sb;
-	struct logfs_segment_header sh;
-	u64 ofs;
-	int err;
-
-	err = logfs_erase_segment(sb, area->a_segno, 0);
-	if (err)
-		return err;
-
-	sh.pad = 0;
-	sh.type = SEG_OSTORE;
-	sh.level = (__force u8)area->a_level;
-	sh.segno = cpu_to_be32(area->a_segno);
-	sh.ec = cpu_to_be32(area->a_erase_count);
-	sh.gec = cpu_to_be64(logfs_super(sb)->s_gec);
-	sh.crc = logfs_crc32(&sh, sizeof(sh), 4);
-
-	logfs_set_segment_erased(sb, area->a_segno, area->a_erase_count,
-			area->a_level);
-
-	ofs = dev_ofs(sb, area->a_segno, 0);
-	area->a_used_bytes = sizeof(sh);
-	logfs_buf_write(area, ofs, &sh, sizeof(sh));
-	return 0;
-}
-
-static const struct logfs_area_ops ostore_area_ops = {
-	.get_free_segment	= ostore_get_free_segment,
-	.get_erase_count	= ostore_get_erase_count,
-	.erase_segment		= ostore_erase_segment,
-};
-
-static void free_area(struct logfs_area *area)
-{
-	if (area)
-		freeseg(area->a_sb, area->a_segno);
-	kfree(area);
-}
-
-void free_areas(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int i;
-
-	for_each_area(i)
-		free_area(super->s_area[i]);
-	free_area(super->s_journal_area);
-}
-
-static struct logfs_area *alloc_area(struct super_block *sb)
-{
-	struct logfs_area *area;
-
-	area = kzalloc(sizeof(*area), GFP_KERNEL);
-	if (!area)
-		return NULL;
-
-	area->a_sb = sb;
-	return area;
-}
-
-static void map_invalidatepage(struct page *page, unsigned int o,
-			       unsigned int l)
-{
-	return;
-}
-
-static int map_releasepage(struct page *page, gfp_t g)
-{
-	/* Don't release these pages */
-	return 0;
-}
-
-static const struct address_space_operations mapping_aops = {
-	.invalidatepage = map_invalidatepage,
-	.releasepage	= map_releasepage,
-	.set_page_dirty = __set_page_dirty_nobuffers,
-};
-
-int logfs_init_mapping(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct address_space *mapping;
-	struct inode *inode;
-
-	inode = logfs_new_meta_inode(sb, LOGFS_INO_MAPPING);
-	if (IS_ERR(inode))
-		return PTR_ERR(inode);
-	super->s_mapping_inode = inode;
-	mapping = inode->i_mapping;
-	mapping->a_ops = &mapping_aops;
-	/* Would it be possible to use __GFP_HIGHMEM as well? */
-	mapping_set_gfp_mask(mapping, GFP_NOFS);
-	return 0;
-}
-
-int logfs_init_areas(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int i = -1;
-
-	super->s_alias_pool = mempool_create_kmalloc_pool(600,
-			sizeof(struct object_alias_item));
-	if (!super->s_alias_pool)
-		return -ENOMEM;
-
-	super->s_journal_area = alloc_area(sb);
-	if (!super->s_journal_area)
-		goto err;
-
-	for_each_area(i) {
-		super->s_area[i] = alloc_area(sb);
-		if (!super->s_area[i])
-			goto err;
-		super->s_area[i]->a_level = GC_LEVEL(i);
-		super->s_area[i]->a_ops = &ostore_area_ops;
-	}
-	btree_init_mempool128(&super->s_object_alias_tree,
-			super->s_btree_pool);
-	return 0;
-
-err:
-	for (i--; i >= 0; i--)
-		free_area(super->s_area[i]);
-	free_area(super->s_journal_area);
-	logfs_mempool_destroy(super->s_alias_pool);
-	return -ENOMEM;
-}
-
-void logfs_cleanup_areas(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	btree_grim_visitor128(&super->s_object_alias_tree, 0, kill_alias);
-}

fs/logfs/super.c

···
-/*
- * fs/logfs/super.c
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <[e-mail]>
- *
- * Generally contains mount/umount code and also serves as a dump area for
- * any functions that don't fit elsewhere and neither justify a file of their
- * own.
- */
-#include "logfs.h"
-#include <linux/bio.h>
-#include <linux/slab.h>
-#include <linux/blkdev.h>
-#include <linux/module.h>
-#include <linux/mtd/mtd.h>
-#include <linux/statfs.h>
-#include <linux/buffer_head.h>
-
-static DEFINE_MUTEX(emergency_mutex);
-static struct page *emergency_page;
-
-struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index)
-{
-	filler_t *filler = (filler_t *)mapping->a_ops->readpage;
-	struct page *page;
-	int err;
-
-	page = read_cache_page(mapping, index, filler, NULL);
-	if (page)
-		return page;
-
-	/* No more pages available, switch to emergency page */
-	printk(KERN_INFO"Logfs: Using emergency page\n");
-	mutex_lock(&emergency_mutex);
-	err = filler(NULL, emergency_page);
-	if (err) {
-		mutex_unlock(&emergency_mutex);
-		printk(KERN_EMERG"Logfs: Error reading emergency page\n");
-		return ERR_PTR(err);
-	}
-	return emergency_page;
-}
-
-void emergency_read_end(struct page *page)
-{
-	if (page == emergency_page)
-		mutex_unlock(&emergency_mutex);
-	else
-		put_page(page);
-}
-
-static void dump_segfile(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_segment_entry se;
-	u32 segno;
-
-	for (segno = 0; segno < super->s_no_segs; segno++) {
-		logfs_get_segment_entry(sb, segno, &se);
-		printk("%3x: %6x %8x", segno, be32_to_cpu(se.ec_level),
-				be32_to_cpu(se.valid));
-		if (++segno < super->s_no_segs) {
-			logfs_get_segment_entry(sb, segno, &se);
-			printk(" %6x %8x", be32_to_cpu(se.ec_level),
-					be32_to_cpu(se.valid));
-		}
-		if (++segno < super->s_no_segs) {
-			logfs_get_segment_entry(sb, segno, &se);
-			printk(" %6x %8x", be32_to_cpu(se.ec_level),
-					be32_to_cpu(se.valid));
-		}
-		if (++segno < super->s_no_segs) {
-			logfs_get_segment_entry(sb, segno, &se);
-			printk(" %6x %8x", be32_to_cpu(se.ec_level),
-					be32_to_cpu(se.valid));
-		}
-		printk("\n");
-	}
-}
-
-/*
- * logfs_crash_dump - dump debug information to device
- *
- * The LogFS superblock only occupies part of a segment.  This function will
- * write as much debug information as it can gather into the spare space.
- */
-void logfs_crash_dump(struct super_block *sb)
-{
-	dump_segfile(sb);
-}
-
-/*
- * FIXME: There should be a reserve for root, similar to ext2.
- */
-int logfs_statfs(struct dentry *dentry, struct kstatfs *stats)
-{
-	struct super_block *sb = dentry->d_sb;
-	struct logfs_super *super = logfs_super(sb);
-
-	stats->f_type		= LOGFS_MAGIC_U32;
-	stats->f_bsize		= sb->s_blocksize;
-	stats->f_blocks		= super->s_size >> LOGFS_BLOCK_BITS >> 3;
-	stats->f_bfree		= super->s_free_bytes >> sb->s_blocksize_bits;
-	stats->f_bavail		= super->s_free_bytes >> sb->s_blocksize_bits;
-	stats->f_files		= 0;
-	stats->f_ffree		= 0;
-	stats->f_namelen	= LOGFS_MAX_NAMELEN;
-	return 0;
-}
-
-static int logfs_sb_set(struct super_block *sb, void *_super)
-{
-	struct logfs_super *super = _super;
-
-	sb->s_fs_info = super;
-	sb->s_mtd = super->s_mtd;
-	sb->s_bdev = super->s_bdev;
-#ifdef CONFIG_BLOCK
-	if (sb->s_bdev)
-		sb->s_bdi = &bdev_get_queue(sb->s_bdev)->backing_dev_info;
-#endif
-#ifdef CONFIG_MTD
-	if (sb->s_mtd)
-		sb->s_bdi = sb->s_mtd->backing_dev_info;
-#endif
-	return 0;
-}
-
-static int logfs_sb_test(struct super_block *sb, void *_super)
-{
-	struct logfs_super *super = _super;
-	struct mtd_info *mtd = super->s_mtd;
-
-	if (mtd && sb->s_mtd == mtd)
-		return 1;
-	if (super->s_bdev && sb->s_bdev == super->s_bdev)
-		return 1;
-	return 0;
-}
-
-static void set_segment_header(struct logfs_segment_header *sh, u8 type,
-		u8 level, u32 segno, u32 ec)
-{
-	sh->pad = 0;
-	sh->type = type;
-	sh->level = level;
-	sh->segno = cpu_to_be32(segno);
-	sh->ec = cpu_to_be32(ec);
-	sh->gec = cpu_to_be64(segno);
-	sh->crc = logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4);
-}
-
-static void logfs_write_ds(struct super_block *sb, struct logfs_disk_super *ds,
-		u32 segno, u32 ec)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_segment_header *sh = &ds->ds_sh;
-	int i;
-
-	memset(ds, 0, sizeof(*ds));
-	set_segment_header(sh, SEG_SUPER, 0, segno, ec);
-
-	ds->ds_ifile_levels	= super->s_ifile_levels;
-	ds->ds_iblock_levels	= super->s_iblock_levels;
-	ds->ds_data_levels	= super->s_data_levels; /* XXX: Remove */
-	ds->ds_segment_shift	= super->s_segshift;
-	ds->ds_block_shift	= sb->s_blocksize_bits;
-	ds->ds_write_shift	= super->s_writeshift;
-	ds->ds_filesystem_size	= cpu_to_be64(super->s_size);
-	ds->ds_segment_size	= cpu_to_be32(super->s_segsize);
-	ds->ds_bad_seg_reserve	= cpu_to_be32(super->s_bad_seg_reserve);
-	ds->ds_feature_incompat	= cpu_to_be64(super->s_feature_incompat);
-	ds->ds_feature_ro_compat= cpu_to_be64(super->s_feature_ro_compat);
-	ds->ds_feature_compat	= cpu_to_be64(super->s_feature_compat);
-	ds->ds_feature_flags	= cpu_to_be64(super->s_feature_flags);
-	ds->ds_root_reserve	= cpu_to_be64(super->s_root_reserve);
-	ds->ds_speed_reserve	= cpu_to_be64(super->s_speed_reserve);
-	journal_for_each(i)
-		ds->ds_journal_seg[i] = cpu_to_be32(super->s_journal_seg[i]);
-	ds->ds_magic		= cpu_to_be64(LOGFS_MAGIC);
-	ds->ds_crc = logfs_crc32(ds, sizeof(*ds),
-			LOGFS_SEGMENT_HEADERSIZE + 12);
-}
-
-static int write_one_sb(struct super_block *sb,
-		struct page *(*find_sb)(struct super_block *sb, u64 *ofs))
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_disk_super *ds;
-	struct logfs_segment_entry se;
-	struct page *page;
-	u64 ofs;
-	u32 ec, segno;
-	int err;
-
-	page = find_sb(sb, &ofs);
-	if (!page)
-		return -EIO;
-	ds = page_address(page);
-	segno = seg_no(sb, ofs);
-	logfs_get_segment_entry(sb, segno, &se);
-	ec = be32_to_cpu(se.ec_level) >> 4;
-	ec++;
-	logfs_set_segment_erased(sb, segno, ec, 0);
-	logfs_write_ds(sb, ds, segno, ec);
-	err = super->s_devops->write_sb(sb, page);
-	put_page(page);
-	return err;
-}
-
-int logfs_write_sb(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int err;
-
-	/* First superblock */
-	err = write_one_sb(sb, super->s_devops->find_first_sb);
-	if (err)
-		return err;
-
-	/* Last superblock */
-	err = write_one_sb(sb, super->s_devops->find_last_sb);
-	if (err)
-		return err;
-	return 0;
-}
-
-static int ds_cmp(const void *ds0, const void *ds1)
-{
-	size_t len = sizeof(struct logfs_disk_super);
-
-	/* We know the segment headers differ, so ignore them */
-	len -= LOGFS_SEGMENT_HEADERSIZE;
-	ds0 += LOGFS_SEGMENT_HEADERSIZE;
-	ds1 += LOGFS_SEGMENT_HEADERSIZE;
-	return memcmp(ds0, ds1, len);
-}
-
-static int logfs_recover_sb(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_disk_super _ds0, *ds0 = &_ds0;
-	struct logfs_disk_super _ds1, *ds1 = &_ds1;
-	int err, valid0, valid1;
-
-	/* read first superblock */
-	err = wbuf_read(sb, super->s_sb_ofs[0], sizeof(*ds0), ds0);
-	if (err)
-		return err;
-	/* read last superblock */
-	err = wbuf_read(sb, super->s_sb_ofs[1], sizeof(*ds1), ds1);
-	if (err)
-		return err;
-	valid0 = logfs_check_ds(ds0) == 0;
-	valid1 = logfs_check_ds(ds1) == 0;
-
-	if (!valid0 && valid1) {
-		printk(KERN_INFO"First superblock is invalid - fixing.\n");
-		return write_one_sb(sb, super->s_devops->find_first_sb);
-	}
-	if (valid0 && !valid1) {
-		printk(KERN_INFO"Last superblock is invalid - fixing.\n");
-		return write_one_sb(sb, super->s_devops->find_last_sb);
-	}
-	if (valid0 && valid1 && ds_cmp(ds0, ds1)) {
-		printk(KERN_INFO"Superblocks don't match - fixing.\n");
-		return logfs_write_sb(sb);
-	}
-	/* If neither is valid now, something's wrong.  Didn't we properly
-	 * check them before?!? */
-	BUG_ON(!valid0 && !valid1);
-	return 0;
-}
-
-static int logfs_make_writeable(struct super_block *sb)
-{
-	int err;
-
-	err = logfs_open_segfile(sb);
-	if (err)
-		return err;
-
-	/* Repair any broken superblock copies */
-	err = logfs_recover_sb(sb);
-	if (err)
-		return err;
-
-	/* Check areas for trailing unaccounted data */
-	err = logfs_check_areas(sb);
-	if (err)
-		return err;
-
-	/* Do one GC pass before any data gets dirtied */
-	logfs_gc_pass(sb);
-
-	/* after all initializations are done, replay the journal
-	 * for rw-mounts, if necessary */
-	err = logfs_replay_journal(sb);
-	if (err)
-		return err;
-
-	return 0;
-}
-
-static int logfs_get_sb_final(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct inode *rootdir;
-	int err;
-
-	/* root dir */
-	rootdir = logfs_iget(sb, LOGFS_INO_ROOT);
-	if (IS_ERR(rootdir))
-		goto fail;
-
-	sb->s_root = d_make_root(rootdir);
-	if (!sb->s_root)
-		goto fail;
-
-	/* at that point we know that ->put_super() will be called */
-	super->s_erase_page = alloc_pages(GFP_KERNEL, 0);
-	if (!super->s_erase_page)
-		return -ENOMEM;
-	memset(page_address(super->s_erase_page), 0xFF, PAGE_SIZE);
-
-	/* FIXME: check for read-only mounts */
-	err = logfs_make_writeable(sb);
-	if (err) {
-		__free_page(super->s_erase_page);
-		return err;
-	}
-
-	log_super("LogFS: Finished mounting\n");
-	return 0;
-
-fail:
-	iput(super->s_master_inode);
-	iput(super->s_segfile_inode);
-	iput(super->s_mapping_inode);
-	return -EIO;
-}
-
-int logfs_check_ds(struct logfs_disk_super *ds)
-{
-	struct logfs_segment_header *sh = &ds->ds_sh;
-
-	if (ds->ds_magic != cpu_to_be64(LOGFS_MAGIC))
-		return -EINVAL;
-	if (sh->crc != logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4))
-		return -EINVAL;
-	if (ds->ds_crc != logfs_crc32(ds, sizeof(*ds),
-				LOGFS_SEGMENT_HEADERSIZE + 12))
-		return -EINVAL;
-	return 0;
-}
-
-static struct page *find_super_block(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct page *first, *last;
-
-	first = super->s_devops->find_first_sb(sb, &super->s_sb_ofs[0]);
-	if (!first || IS_ERR(first))
-		return NULL;
-	last = super->s_devops->find_last_sb(sb, &super->s_sb_ofs[1]);
-	if (!last || IS_ERR(last)) {
-		put_page(first);
-		return NULL;
-	}
-
-	if (!logfs_check_ds(page_address(first))) {
-		put_page(last);
-		return first;
-	}
-
-	/* First one didn't work, try the second superblock */
-	if (!logfs_check_ds(page_address(last))) {
-		put_page(first);
-		return last;
-	}
-
-	/* Neither worked, sorry folks */
-	put_page(first);
-	put_page(last);
-	return NULL;
-}
-
-static int __logfs_read_sb(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct page *page;
-	struct logfs_disk_super *ds;
-	int i;
-
-	page = find_super_block(sb);
-	if (!page)
-		return -EINVAL;
-
-	ds = page_address(page);
-	super->s_size = be64_to_cpu(ds->ds_filesystem_size);
-	super->s_root_reserve = be64_to_cpu(ds->ds_root_reserve);
-	super->s_speed_reserve = be64_to_cpu(ds->ds_speed_reserve);
-	super->s_bad_seg_reserve = be32_to_cpu(ds->ds_bad_seg_reserve);
-	super->s_segsize = 1 << ds->ds_segment_shift;
-	super->s_segmask = (1 << ds->ds_segment_shift) - 1;
-	super->s_segshift = ds->ds_segment_shift;
-	sb->s_blocksize = 1 << ds->ds_block_shift;
-	sb->s_blocksize_bits = ds->ds_block_shift;
-	super->s_writesize = 1 << ds->ds_write_shift;
-	super->s_writeshift = ds->ds_write_shift;
-	super->s_no_segs = super->s_size >> super->s_segshift;
-	super->s_no_blocks = super->s_segsize >> sb->s_blocksize_bits;
-	super->s_feature_incompat = be64_to_cpu(ds->ds_feature_incompat);
-	super->s_feature_ro_compat = be64_to_cpu(ds->ds_feature_ro_compat);
-	super->s_feature_compat = be64_to_cpu(ds->ds_feature_compat);
-	super->s_feature_flags = be64_to_cpu(ds->ds_feature_flags);
-
-	journal_for_each(i)
-		super->s_journal_seg[i] = be32_to_cpu(ds->ds_journal_seg[i]);
-
-	super->s_ifile_levels = ds->ds_ifile_levels;
-	super->s_iblock_levels = ds->ds_iblock_levels;
-	super->s_data_levels = ds->ds_data_levels;
-	super->s_total_levels = super->s_ifile_levels + super->s_iblock_levels
-		+ super->s_data_levels;
-	put_page(page);
-	return 0;
-}
-
-static int logfs_read_sb(struct super_block *sb, int read_only)
-{
-	struct logfs_super *super = logfs_super(sb);
-	int ret;
-
-	super->s_btree_pool = mempool_create(32, btree_alloc, btree_free, NULL);
-	if (!super->s_btree_pool)
-		return -ENOMEM;
-
-	btree_init_mempool64(&super->s_shadow_tree.new, super->s_btree_pool);
-	btree_init_mempool64(&super->s_shadow_tree.old, super->s_btree_pool);
-	btree_init_mempool32(&super->s_shadow_tree.segment_map,
-			super->s_btree_pool);
-
-	ret = logfs_init_mapping(sb);
-	if (ret)
-		return ret;
-
-	ret = __logfs_read_sb(sb);
-	if (ret)
-		return ret;
-
-	if (super->s_feature_incompat & ~LOGFS_FEATURES_INCOMPAT)
-		return -EIO;
-	if ((super->s_feature_ro_compat & ~LOGFS_FEATURES_RO_COMPAT) &&
-			!read_only)
-		return -EIO;
-
-	ret = logfs_init_rw(sb);
-	if (ret)
-		return ret;
-
-	ret = logfs_init_areas(sb);
-	if (ret)
-		return ret;
-
-	ret = logfs_init_gc(sb);
-	if (ret)
-		return ret;
-
-	ret = logfs_init_journal(sb);
-	if (ret)
-		return ret;
-
-	return 0;
-}
-
-static void logfs_kill_sb(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-
-	log_super("LogFS: Start unmounting\n");
-	/* Alias entries slow down mount, so evict as many as possible */
-	sync_filesystem(sb);
-	logfs_write_anchor(sb);
-	free_areas(sb);
-
-	/*
-	 * From this point on alias entries are simply dropped - and any
-	 * writes to the object store are considered bugs.
-	 */
-	log_super("LogFS: Now in shutdown\n");
-	generic_shutdown_super(sb);
-	super->s_flags |= LOGFS_SB_FLAG_SHUTDOWN;
-
-	BUG_ON(super->s_dirty_used_bytes || super->s_dirty_free_bytes);
-
-	logfs_cleanup_gc(sb);
-	logfs_cleanup_journal(sb);
-	logfs_cleanup_areas(sb);
-	logfs_cleanup_rw(sb);
-	if (super->s_erase_page)
-		__free_page(super->s_erase_page);
-	super->s_devops->put_device(super);
-	logfs_mempool_destroy(super->s_btree_pool);
-	logfs_mempool_destroy(super->s_alias_pool);
-	kfree(super);
-	log_super("LogFS: Finished unmounting\n");
-}
-
-static struct dentry *logfs_get_sb_device(struct logfs_super *super,
-		struct file_system_type *type, int flags)
-{
-	struct super_block *sb;
-	int err = -ENOMEM;
-	static int mount_count;
-
-	log_super("LogFS: Start mount %x\n", mount_count++);
-
-	err = -EINVAL;
-	sb = sget(type, logfs_sb_test, logfs_sb_set, flags | MS_NOATIME, super);
-	if (IS_ERR(sb)) {
-		super->s_devops->put_device(super);
-		kfree(super);
-		return ERR_CAST(sb);
-	}
-
-	if (sb->s_root) {
-		/* Device is already in use */
-		super->s_devops->put_device(super);
-		kfree(super);
-		return dget(sb->s_root);
-	}
-
-	/*
-	 * sb->s_maxbytes is limited to 8TB.  On 32bit systems, the page cache
-	 * only covers 16TB and the upper 8TB are used for indirect blocks.
-	 * On 64bit system we could bump up the limit, but that would make
-	 * the filesystem incompatible with 32bit systems.
-	 */
-	sb->s_maxbytes	= (1ull << 43) - 1;
-	sb->s_max_links = LOGFS_LINK_MAX;
-	sb->s_op	= &logfs_super_operations;
-
-	err = logfs_read_sb(sb, sb->s_flags & MS_RDONLY);
-	if (err)
-		goto err1;
-
-	sb->s_flags |= MS_ACTIVE;
-	err = logfs_get_sb_final(sb);
-	if (err) {
-		deactivate_locked_super(sb);
-		return ERR_PTR(err);
-	}
-	return dget(sb->s_root);
-
-err1:
-	/* no ->s_root, no ->put_super() */
-	iput(super->s_master_inode);
-	iput(super->s_segfile_inode);
-	iput(super->s_mapping_inode);
-	deactivate_locked_super(sb);
-	return ERR_PTR(err);
-}
-
-static struct dentry *logfs_mount(struct file_system_type *type, int flags,
-		const char *devname, void *data)
-{
-	ulong mtdnr;
-	struct logfs_super *super;
-	int err;
-
-	super = kzalloc(sizeof(*super), GFP_KERNEL);
-	if (!super)
-		return ERR_PTR(-ENOMEM);
-
-	mutex_init(&super->s_dirop_mutex);
-	mutex_init(&super->s_object_alias_mutex);
-	INIT_LIST_HEAD(&super->s_freeing_list);
-
-	if (!devname)
-		err = logfs_get_sb_bdev(super, type, devname);
-	else if (strncmp(devname, "mtd", 3))
-		err = logfs_get_sb_bdev(super, type, devname);
-	else {
-		char *garbage;
-		mtdnr = simple_strtoul(devname+3, &garbage, 0);
-		if (*garbage)
-			err = -EINVAL;
-		else
-			err = logfs_get_sb_mtd(super, mtdnr);
-	}
-
-	if (err) {
-		kfree(super);
-		return ERR_PTR(err);
-	}
-
-	return logfs_get_sb_device(super, type, flags);
-}
-
-static struct file_system_type logfs_fs_type = {
-	.owner		= THIS_MODULE,
-	.name		= "logfs",
-	.mount		= logfs_mount,
-	.kill_sb	= logfs_kill_sb,
-	.fs_flags	= FS_REQUIRES_DEV,
-
-};
-MODULE_ALIAS_FS("logfs");
-
-static int __init logfs_init(void)
-{
-	int ret;
-
-	emergency_page = alloc_pages(GFP_KERNEL, 0);
-	if (!emergency_page)
-		return -ENOMEM;
-
-	ret = logfs_compr_init();
-	if (ret)
-		goto out1;
-
-	ret = logfs_init_inode_cache();
-	if (ret)
-		goto out2;
-
-	ret = register_filesystem(&logfs_fs_type);
-	if (!ret)
-		return 0;
-	logfs_destroy_inode_cache();
-out2:
-	logfs_compr_exit();
-out1:
-	__free_pages(emergency_page, 0);
-	return ret;
-}
-
-static void __exit logfs_exit(void)
-{
-	unregister_filesystem(&logfs_fs_type);
-	logfs_destroy_inode_cache();
-	logfs_compr_exit();
-	__free_pages(emergency_page, 0);
-}
-
-module_init(logfs_init);
-module_exit(logfs_exit);
-
-MODULE_LICENSE("GPL v2");
-MODULE_AUTHOR("Joern Engel <[e-mail]>");
-MODULE_DESCRIPTION("scalable flash filesystem");

fs/namei.c

···
 	return 1;
 }
 
+enum {WALK_FOLLOW = 1, WALK_MORE = 2};
+
 /*
  * Do we need to follow links? We _really_ want to be able
  * to do this check without having to look at inode->i_op,
  * so we keep a cache of "no, this doesn't need follow_link"
  * for the common case.
  */
-static inline int should_follow_link(struct nameidata *nd, struct path *link,
-				     int follow,
-				     struct inode *inode, unsigned seq)
+static inline int step_into(struct nameidata *nd, struct path *path,
+			    int flags, struct inode *inode, unsigned seq)
 {
-	if (likely(!d_is_symlink(link->dentry)))
+	if (!(flags & WALK_MORE) && nd->depth)
+		put_link(nd);
+	if (likely(!d_is_symlink(path->dentry)) ||
+	   !(flags & WALK_FOLLOW || nd->flags & LOOKUP_FOLLOW)) {
+		/* not a symlink or should not follow */
+		path_to_nameidata(path, nd);
+		nd->inode = inode;
+		nd->seq = seq;
 		return 0;
-	if (!follow)
-		return 0;
+	}
 	/* make sure that d_is_symlink above matches inode */
 	if (nd->flags & LOOKUP_RCU) {
-		if (read_seqcount_retry(&link->dentry->d_seq, seq))
+		if (read_seqcount_retry(&path->dentry->d_seq, seq))
 			return -ECHILD;
 	}
-	return pick_link(nd, link, inode, seq);
+	return pick_link(nd, path, inode, seq);
 }
-
-enum {WALK_GET = 1, WALK_PUT = 2};
 
 static int walk_component(struct nameidata *nd, int flags)
 {
···
 	 */
 	if (unlikely(nd->last_type != LAST_NORM)) {
 		err = handle_dots(nd, nd->last_type);
-		if (flags & WALK_PUT)
+		if (!(flags & WALK_MORE) && nd->depth)
 			put_link(nd);
 		return err;
 	}
···
 		inode = d_backing_inode(path.dentry);
 	}
 
-	if (flags & WALK_PUT)
-		put_link(nd);
-	err = should_follow_link(nd, &path, flags & WALK_GET, inode, seq);
-	if (unlikely(err))
-		return err;
-	path_to_nameidata(&path, nd);
-	nd->inode = inode;
-	nd->seq = seq;
-	return 0;
+	return step_into(nd, &path, flags, inode, seq);
 }
 
 /*
···
 			if (!name)
 				return 0;
 			/* last component of nested symlink */
-			err = walk_component(nd, WALK_GET | WALK_PUT);
+			err = walk_component(nd, WALK_FOLLOW);
 		} else {
-			err = walk_component(nd, WALK_GET);
+			/* not the last component */
+			err = walk_component(nd, WALK_FOLLOW | WALK_MORE);
 		}
 		if (err < 0)
 			return err;
···
 		nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
 
 	nd->flags &= ~LOOKUP_PARENT;
-	return walk_component(nd,
-			nd->flags & LOOKUP_FOLLOW
-				? nd->depth
-					? WALK_PUT | WALK_GET
-					: WALK_GET
-				: 0);
+	return walk_component(nd, 0);
 }
 
 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
···
 }
 EXPORT_SYMBOL(user_path_at_empty);
 
-/*
- * NB: most callers don't do anything directly with the reference to the
- *     to struct filename, but the nd->last pointer points into the name string
- *     allocated by getname. So we must hold the reference to it until all
- *     path-walking is complete.
- */
-static inline struct filename *
-user_path_parent(int dfd, const char __user *path,
-		 struct path *parent,
-		 struct qstr *last,
-		 int *type,
-		 unsigned int flags)
-{
-	/* only LOOKUP_REVAL is allowed in extra flags */
-	return filename_parentat(dfd, getname(path), flags & LOOKUP_REVAL,
-				 parent, last, type);
-}
-
 /**
  * mountpoint_last - look up last component for umount
  * @nd:   pathwalk nameidata - currently pointing at parent directory of "last"
- * @path: pointer to container for result
  *
  * This is a special lookup_last function just for umount. In this case, we
  * need to resolve the path without doing any revalidation.
···
  *
  * Returns:
  * -error: if there was an error during lookup. This includes -ENOENT if the
- *         lookup found a negative dentry. The nd->path reference will also be
- *         put in this case.
+ *         lookup found a negative dentry.
  *
- * 0:      if we successfully resolved nd->path and found it to not to be a
- *         symlink that needs to be followed. "path" will also be populated.
- *         The nd->path reference will also be put.
+ * 0:      if we successfully resolved nd->last and found it to not to be a
+ *         symlink that needs to be followed.
  *
  * 1:      if we successfully resolved nd->last and found it to be a symlink
- *         that needs to be followed. "path" will be populated with the path
- *         to the link, and nd->path will *not* be put.
+ *         that needs to be followed.
  */
 static int
-mountpoint_last(struct nameidata *nd, struct path *path)
+mountpoint_last(struct nameidata *nd)
 {
 	int error = 0;
-	struct dentry *dentry;
 	struct dentry *dir = nd->path.dentry;
+	struct path path;
 
 	/* If we're in rcuwalk, drop out of it to handle last component */
 	if (nd->flags & LOOKUP_RCU) {
···
 		error = handle_dots(nd, nd->last_type);
 		if (error)
 			return error;
-		dentry = dget(nd->path.dentry);
+		path.dentry = dget(nd->path.dentry);
 	} else {
-		dentry = d_lookup(dir, &nd->last);
-		if (!dentry) {
+		path.dentry = d_lookup(dir, &nd->last);
+		if (!path.dentry) {
 			/*
 			 * No cached dentry. Mounted dentries are pinned in the
 			 * cache, so that means that this dentry is probably
 			 * a symlink or the path doesn't actually point
 			 * to a mounted dentry.
 			 */
-			dentry = lookup_slow(&nd->last, dir,
+			path.dentry = lookup_slow(&nd->last, dir,
 					     nd->flags | LOOKUP_NO_REVAL);
-			if (IS_ERR(dentry))
-				return PTR_ERR(dentry);
+			if (IS_ERR(path.dentry))
+				return PTR_ERR(path.dentry);
 		}
 	}
-	if (d_is_negative(dentry)) {
-		dput(dentry);
+	if (d_is_negative(path.dentry)) {
+		dput(path.dentry);
 		return -ENOENT;
 	}
-	if (nd->depth)
-		put_link(nd);
-	path->dentry = dentry;
-	path->mnt = nd->path.mnt;
-	error = should_follow_link(nd, path, nd->flags & LOOKUP_FOLLOW,
-				   d_backing_inode(dentry), 0);
-	if (unlikely(error))
-		return error;
-	mntget(path->mnt);
-	follow_mount(path);
-	return 0;
+	path.mnt = nd->path.mnt;
+	return step_into(nd, &path, 0, d_backing_inode(path.dentry), 0);
 }
 
 /**
···
 	if (IS_ERR(s))
 		return PTR_ERR(s);
 	while (!(err = link_path_walk(s, nd)) &&
-		(err = mountpoint_last(nd, path)) > 0) {
+		(err = mountpoint_last(nd)) > 0) {
 		s = trailing_symlink(nd);
 		if (IS_ERR(s)) {
 			err = PTR_ERR(s);
 			break;
 		}
+	}
+	if (!err) {
+		*path = nd->path;
+		nd->path.mnt = NULL;
+		nd->path.dentry = NULL;
+		follow_mount(path);
 	}
 	terminate_walk(nd);
 	return err;
···
 	seq = 0;	/* out of RCU mode, so the value doesn't matter */
 	inode = d_backing_inode(path.dentry);
 finish_lookup:
-	if (nd->depth)
-		put_link(nd);
-	error = should_follow_link(nd, &path, nd->flags & LOOKUP_FOLLOW,
-				   inode, seq);
+	error = step_into(nd, &path, 0, inode, seq);
 	if (unlikely(error))
 		return error;
-
-	path_to_nameidata(&path, nd);
-	nd->inode = inode;
-	nd->seq = seq;
-	/* Why this, you ask?  _Now_ we might have grown LOOKUP_JUMPED... */
 finish_open:
+	/* Why this, you ask?  _Now_ we might have grown LOOKUP_JUMPED... */
 	error = complete_walk(nd);
 	if (error)
 		return error;
···
 	int type;
 	unsigned int lookup_flags = 0;
 retry:
-	name = user_path_parent(dfd, pathname,
-				&path, &last, &type, lookup_flags);
+	name = filename_parentat(dfd, getname(pathname), lookup_flags,
+				&path, &last, &type);
 	if (IS_ERR(name))
 		return PTR_ERR(name);
 
···
 	struct inode *delegated_inode = NULL;
 	unsigned int lookup_flags = 0;
 retry:
-	name = user_path_parent(dfd, pathname,
-				&path, &last, &type, lookup_flags);
+	name = filename_parentat(dfd, getname(pathname), lookup_flags,
+				&path, &last, &type);
 	if (IS_ERR(name))
 		return PTR_ERR(name);
 
···
 		target_flags = 0;
 
 retry:
-	from = user_path_parent(olddfd, oldname,
-				&old_path, &old_last, &old_type, lookup_flags);
+	from = filename_parentat(olddfd, getname(oldname), lookup_flags,
+				&old_path, &old_last, &old_type);
 	if (IS_ERR(from)) {
 		error = PTR_ERR(from);
 		goto exit;
 	}
 
-	to = user_path_parent(newdfd, newname,
-				&new_path, &new_last, &new_type, lookup_flags);
+	to = filename_parentat(newdfd, getname(newname), lookup_flags,
+				&new_path, &new_last, &new_type);
 	if (IS_ERR(to)) {
 		error = PTR_ERR(to);
 		goto exit1;

fs/ncpfs/file.c

···
 				      bufsize - (pos % bufsize),
 				      iov_iter_count(from));
 
-		if (copy_from_iter(bouncebuffer, to_write, from) != to_write) {
+		if (!copy_from_iter_full(bouncebuffer, to_write, from)) {
 			errno = -EFAULT;
 			break;
 		}

fs/orangefs/devorangefs-req.c

···
 		__u64 tag;
 	} head;
 	int total = ret = iov_iter_count(iter);
-	int n;
 	int downcall_size = sizeof(struct orangefs_downcall_s);
 	int head_size = sizeof(head);
 
···
 		return -EFAULT;
 	}
      
-	n = copy_from_iter(&head, head_size, iter);
-	if (n < head_size) {
+	if (!copy_from_iter_full(&head, head_size, iter)) {
 		gossip_err("%s: failed to copy head.\n", __func__);
 		return -EFAULT;
 	}
···
 		return ret;
 	}
 
-	n = copy_from_iter(&op->downcall, downcall_size, iter);
-	if (n != downcall_size) {
+	if (!copy_from_iter_full(&op->downcall, downcall_size, iter)) {
 		gossip_err("%s: failed to copy downcall.\n", __func__);
 		goto Efault;
 	}
···
 		goto Enomem;
 	}
 	memset(op->downcall.trailer_buf, 0, op->downcall.trailer_size);
-	n = copy_from_iter(op->downcall.trailer_buf,
-			   op->downcall.trailer_size,
-			   iter);
-	if (n != op->downcall.trailer_size) {
+	if (!copy_from_iter_full(op->downcall.trailer_buf,
+			         op->downcall.trailer_size, iter)) {
 		gossip_err("%s: failed to copy trailer.\n", __func__);
 		vfree(op->downcall.trailer_buf);
 		goto Efault;

fs/orangefs/file.c

···
 {
 	int rc = -EINVAL;
 
-	if (ORANGEFS_SB(filp->f_inode->i_sb)->flags & ORANGEFS_OPT_LOCAL_LOCK) {
+	if (ORANGEFS_SB(file_inode(filp)->i_sb)->flags & ORANGEFS_OPT_LOCAL_LOCK) {
 		if (cmd == F_GETLK) {
 			rc = 0;
 			posix_test_lock(filp, fl);

fs/orangefs/orangefs-debugfs.c

···
 	char *debug_string;
 	struct orangefs_kernel_op_s *new_op = NULL;
 	struct client_debug_mask c_mask = { NULL, 0, 0 };
+	char *s;
 
 	gossip_debug(GOSSIP_DEBUGFS_DEBUG,
 		"orangefs_debug_write: %pD\n",
···
 	}
 
 	mutex_lock(&orangefs_debug_lock);
-	memset(file->f_inode->i_private, 0, ORANGEFS_MAX_DEBUG_STRING_LEN);
-	sprintf((char *)file->f_inode->i_private, "%s\n", debug_string);
+	s = file_inode(file)->i_private;
+	memset(s, 0, ORANGEFS_MAX_DEBUG_STRING_LEN);
+	sprintf(s, "%s\n", debug_string);
 	mutex_unlock(&orangefs_debug_lock);
 
 	*ppos += count;

fs/overlayfs/copy_up.c

···
 {
 	const struct dentry *dentry = data;
 
-	if (f->f_inode == d_inode(dentry))
+	if (file_inode(f) == d_inode(dentry))
 		pr_warn_ratelimited("overlayfs: Warning: Copying up %pD, but open R/O on fd %u which will cease to be coherent [pid=%d %s]\n",
 				    f, fd, current->pid, current->comm);
 	return 0;

include/linux/skbuff.h

···
 
 	if (skb->ip_summed == CHECKSUM_NONE) {
 		__wsum csum = 0;
-		if (csum_and_copy_from_iter(skb_put(skb, copy), copy,
-					    &csum, from) == copy) {
+		if (csum_and_copy_from_iter_full(skb_put(skb, copy), copy,
+					         &csum, from)) {
 			skb->csum = csum_block_add(skb->csum, csum, off);
 			return 0;
 		}
-	} else if (copy_from_iter(skb_put(skb, copy), copy, from) == copy)
+	} else if (copy_from_iter_full(skb_put(skb, copy), copy, from))
 		return 0;
 
 	__skb_trim(skb, off);

include/linux/uio.h

···
 			 struct iov_iter *i);
 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
+bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i);
 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
+bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i);
 size_t iov_iter_zero(size_t bytes, struct iov_iter *);
 unsigned long iov_iter_alignment(const struct iov_iter *i);
 unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
···
 }
 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
+bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
 
 int import_iovec(int type, const struct iovec __user * uvector,
 		 unsigned nr_segs, unsigned fast_segs,

include/net/sock.h

···
 {
 	if (skb->ip_summed == CHECKSUM_NONE) {
 		__wsum csum = 0;
-		if (csum_and_copy_from_iter(to, copy, &csum, from) != copy)
+		if (!csum_and_copy_from_iter_full(to, copy, &csum, from))
 			return -EFAULT;
 		skb->csum = csum_block_add(skb->csum, csum, offset);
 	} else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
-		if (copy_from_iter_nocache(to, copy, from) != copy)
+		if (!copy_from_iter_full_nocache(to, copy, from))
 			return -EFAULT;
-	} else if (copy_from_iter(to, copy, from) != copy)
+	} else if (!copy_from_iter_full(to, copy, from))
 		return -EFAULT;
 
 	return 0;

include/net/udplite.h

···
 				      int len, int odd, struct sk_buff *skb)
 {
 	struct msghdr *msg = from;
-	return copy_from_iter(to, len, &msg->msg_iter) != len ? -EFAULT : 0;
+	return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
 }
 
 /* Designate sk as UDP-Lite socket */

kernel/audit_watch.c

···
 	exe_file = get_task_exe_file(tsk);
 	if (!exe_file)
 		return 0;
-	ino = exe_file->f_inode->i_ino;
-	dev = exe_file->f_inode->i_sb->s_dev;
+	ino = file_inode(exe_file)->i_ino;
+	dev = file_inode(exe_file)->i_sb->s_dev;
 	fput(exe_file);
 	return audit_mark_compare(mark, ino, dev);
 }

kernel/events/core.c

···
 				     struct file *file, unsigned long offset,
 				     unsigned long size)
 {
-	if (filter->inode != file->f_inode)
+	if (filter->inode != file_inode(file))
 		return false;
 
 	if (filter->offset > offset + size)

kernel/locking/qspinlock_stat.h

···
 	/*
 	 * Get the counter ID stored in file->f_inode->i_private
 	 */
-	if (!file->f_inode) {
-		WARN_ON_ONCE(1);
-		return -EBADF;
-	}
-	counter = (long)(file->f_inode->i_private);
+	counter = (long)file_inode(file)->i_private;
 
 	if (counter >= qstat_num)
 		return -EBADF;
···
 	/*
 	 * Get the counter ID stored in file->f_inode->i_private
 	 */
-	if (!file->f_inode) {
-		WARN_ON_ONCE(1);
-		return -EBADF;
-	}
-	if ((long)(file->f_inode->i_private) != qstat_reset_cnts)
+	if ((long)file_inode(file)->i_private != qstat_reset_cnts)
 		return count;
 
 	for_each_possible_cpu(cpu) {

kernel/printk/printk.c

···
 		return -ENOMEM;
 
 	buf[len] = '\0';
-	if (copy_from_iter(buf, len, from) != len) {
+	if (!copy_from_iter_full(buf, len, from)) {
 		kfree(buf);
 		return -EFAULT;
 	}

lib/iov_iter.c

···
 }
 EXPORT_SYMBOL(copy_from_iter);
 
+bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
+{
+	char *to = addr;
+	if (unlikely(i->type & ITER_PIPE)) {
+		WARN_ON(1);
+		return false;
+	}
+	if (unlikely(i->count < bytes))				\
+		return false;
+
+	iterate_all_kinds(i, bytes, v, ({
+		if (__copy_from_user((to += v.iov_len) - v.iov_len,
+				      v.iov_base, v.iov_len))
+			return false;
+		0;}),
+		memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
+				 v.bv_offset, v.bv_len),
+		memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
+	)
+
+	iov_iter_advance(i, bytes);
+	return true;
+}
+EXPORT_SYMBOL(copy_from_iter_full);
+
 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
 {
 	char *to = addr;
···
 	return bytes;
 }
 EXPORT_SYMBOL(copy_from_iter_nocache);
+
+bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
+{
+	char *to = addr;
+	if (unlikely(i->type & ITER_PIPE)) {
+		WARN_ON(1);
+		return false;
+	}
+	if (unlikely(i->count < bytes))				\
+		return false;
+	iterate_all_kinds(i, bytes, v, ({
+		if (__copy_from_user_nocache((to += v.iov_len) - v.iov_len,
+					     v.iov_base, v.iov_len))
+			return false;
+		0;}),
+		memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
+				 v.bv_offset, v.bv_len),
+		memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
+	)
+
+	iov_iter_advance(i, bytes);
+	return true;
+}
+EXPORT_SYMBOL(copy_from_iter_full_nocache);
 
 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
 			 struct iov_iter *i)
···
 	}
 	iterate_and_advance(i, bytes, v, ({
 		int err = 0;
-		next = csum_and_copy_from_user(v.iov_base, 
+		next = csum_and_copy_from_user(v.iov_base,
 					       (to += v.iov_len) - v.iov_len,
 					       v.iov_len, 0, &err);
 		if (!err) {
···
 }
 EXPORT_SYMBOL(csum_and_copy_from_iter);
 
+bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum,
+			       struct iov_iter *i)
+{
+	char *to = addr;
+	__wsum sum, next;
+	size_t off = 0;
+	sum = *csum;
+	if (unlikely(i->type & ITER_PIPE)) {
+		WARN_ON(1);
+		return false;
+	}
+	if (unlikely(i->count < bytes))
+		return false;
+	iterate_all_kinds(i, bytes, v, ({
+		int err = 0;
+		next = csum_and_copy_from_user(v.iov_base,
+					       (to += v.iov_len) - v.iov_len,
+					       v.iov_len, 0, &err);
+		if (err)
+			return false;
+		sum = csum_block_add(sum, next, off);
+		off += v.iov_len;
+		0;
+	}), ({
+		char *p = kmap_atomic(v.bv_page);
+		next = csum_partial_copy_nocheck(p + v.bv_offset,
+						 (to += v.bv_len) - v.bv_len,
+						 v.bv_len, 0);
+		kunmap_atomic(p);
+		sum = csum_block_add(sum, next, off);
+		off += v.bv_len;
+	}),({
+		next = csum_partial_copy_nocheck(v.iov_base,
+						 (to += v.iov_len) - v.iov_len,
+						 v.iov_len, 0);
+		sum = csum_block_add(sum, next, off);
+		off += v.iov_len;
+	})
+	)
+	*csum = sum;
+	iov_iter_advance(i, bytes);
+	return true;
+}
+EXPORT_SYMBOL(csum_and_copy_from_iter_full);
+
 size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
 			     struct iov_iter *i)
 {
···
 	iterate_and_advance(i, bytes, v, ({
 		int err = 0;
 		next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
-					     v.iov_base, 
+					     v.iov_base,
 					     v.iov_len, 0, &err);
 		if (!err) {
 			sum = csum_block_add(sum, next, off);

net/atm/common.c

···
 		goto out;
 	skb->dev = NULL; /* for paths shared with net_device interfaces */
 	ATM_SKB(skb)->atm_options = vcc->atm_options;
-	if (copy_from_iter(skb_put(skb, size), size, &m->msg_iter) != size) {
+	if (!copy_from_iter_full(skb_put(skb, size), size, &m->msg_iter)) {
 		kfree_skb(skb);
 		error = -EFAULT;
 		goto out;

net/bluetooth/l2cap_core.c

···
 	struct sk_buff **frag;
 	int sent = 0;
 
-	if (copy_from_iter(skb_put(skb, count), count, &msg->msg_iter) != count)
+	if (!copy_from_iter_full(skb_put(skb, count), count, &msg->msg_iter))
 		return -EFAULT;
 
 	sent += count;
···
 
 		*frag = tmp;
 
-		if (copy_from_iter(skb_put(*frag, count), count,
-				   &msg->msg_iter) != count)
+		if (!copy_from_iter_full(skb_put(*frag, count), count,
+				   &msg->msg_iter))
 			return -EFAULT;
 
 		sent += count;

net/ipv4/ip_output.c

···
 	struct msghdr *msg = from;
 
 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
-		if (copy_from_iter(to, len, &msg->msg_iter) != len)
+		if (!copy_from_iter_full(to, len, &msg->msg_iter))
 			return -EFAULT;
 	} else {
 		__wsum csum = 0;
-		if (csum_and_copy_from_iter(to, len, &csum, &msg->msg_iter) != len)
+		if (!csum_and_copy_from_iter_full(to, len, &csum, &msg->msg_iter))
 			return -EFAULT;
 		skb->csum = csum_block_add(skb->csum, csum, odd);
 	}

net/ipv4/ping.c

···
 		fraglen -= sizeof(struct icmphdr);
 		if (fraglen < 0)
 			BUG();
-		if (csum_and_copy_from_iter(to + sizeof(struct icmphdr),
+		if (!csum_and_copy_from_iter_full(to + sizeof(struct icmphdr),
 			    fraglen, &pfh->wcheck,
-			    &pfh->msg->msg_iter) != fraglen)
+			    &pfh->msg->msg_iter))
 			return -EFAULT;
 	} else if (offset < sizeof(struct icmphdr)) {
 			BUG();
 	} else {
-		if (csum_and_copy_from_iter(to, fraglen, &pfh->wcheck,
-					    &pfh->msg->msg_iter) != fraglen)
+		if (!csum_and_copy_from_iter_full(to, fraglen, &pfh->wcheck,
+					    &pfh->msg->msg_iter))
 			return -EFAULT;
 	}
 

net/packet/af_packet.c

···
 static int packet_snd_vnet_parse(struct msghdr *msg, size_t *len,
 				 struct virtio_net_hdr *vnet_hdr)
 {
-	int n;
-
 	if (*len < sizeof(*vnet_hdr))
 		return -EINVAL;
 	*len -= sizeof(*vnet_hdr);
 
-	n = copy_from_iter(vnet_hdr, sizeof(*vnet_hdr), &msg->msg_iter);
-	if (n != sizeof(*vnet_hdr))
+	if (!copy_from_iter_full(vnet_hdr, sizeof(*vnet_hdr), &msg->msg_iter))
 		return -EFAULT;
 
 	return __packet_snd_vnet_parse(vnet_hdr, *len);

net/tipc/msg.c

···
 		__skb_queue_tail(list, skb);
 		skb_copy_to_linear_data(skb, mhdr, mhsz);
 		pktpos = skb->data + mhsz;
-		if (copy_from_iter(pktpos, dsz, &m->msg_iter) == dsz)
+		if (copy_from_iter_full(pktpos, dsz, &m->msg_iter))
 			return dsz;
 		rc = -EFAULT;
 		goto error;
···
 		if (drem < pktrem)
 			pktrem = drem;
 
-		if (copy_from_iter(pktpos, pktrem, &m->msg_iter) != pktrem) {
+		if (!copy_from_iter_full(pktpos, pktrem, &m->msg_iter)) {
 			rc = -EFAULT;
 			goto error;
 		}

security/keys/keyctl.c

···
 		}
 
 		ret = -EFAULT;
-		if (copy_from_iter(payload, plen, from) != plen)
+		if (!copy_from_iter_full(payload, plen, from))
 			goto error2;
 	}
 

security/smack/smack_lsm.c

···
 {
 	struct task_smack *tsp = cred->security;
 	struct smack_known *sskp = tsp->smk_task;
-	struct inode *inode = file->f_inode;
+	struct inode *inode = file_inode(file);
 	struct inode_smack *isp = inode->i_security;
 	char acc[SMK_NUM_ACCESS_TYPE + 1];