Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
"The siginificant new ext4 feature this time around is Harshad's new
fast_commit mode.

In addition, thanks to Mauricio for fixing a race where mmap'ed pages
that are being changed in parallel with a data=journal transaction
commit could result in bad checksums in the failure that could cause
journal replays to fail.

Also notable is Ritesh's buffered write optimization which can result
in significant improvements on parallel write workloads. (The kernel
test robot reported a 330.6% improvement on fio.write_iops on a 96
core system using DAX)

Besides that, we have the usual miscellaneous cleanups and bug fixes"

Link: https://lore.kernel.org/r/20200925071217.GO28663@shao2-debian

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (46 commits)
ext4: fix invalid inode checksum
ext4: add fast commit stats in procfs
ext4: add a mount opt to forcefully turn fast commits on
ext4: fast commit recovery path
jbd2: fast commit recovery path
ext4: main fast-commit commit path
jbd2: add fast commit machinery
ext4 / jbd2: add fast commit initialization
ext4: add fast_commit feature and handling for extended mount options
doc: update ext4 and journalling docs to include fast commit feature
ext4: Detect already used quota file early
jbd2: avoid transaction reuse after reformatting
ext4: use the normal helper to get the actual inode
ext4: fix bs < ps issue reported with dioread_nolock mount opt
ext4: data=journal: write-protect pages on j_submit_inode_data_buffers()
ext4: data=journal: fixes for ext4_page_mkwrite()
jbd2, ext4, ocfs2: introduce/use journal callbacks j_submit|finish_inode_data_buffers()
jbd2: introduce/export functions jbd2_journal_submit|finish_inode_data_buffers()
ext4: introduce ext4_sb_bread_unmovable() to replace sb_bread_unmovable()
ext4: use ext4_sb_bread() instead of sb_bread()
...

Documentation/filesystems/ext4/journal.rst

···
 safest. If ``data=writeback``, dirty data blocks are not flushed to the
 disk before the metadata are written to disk through the journal.
 
+In case of ``data=ordered`` mode, Ext4 also supports fast commits which
+help reduce commit latency significantly. The default ``data=ordered``
+mode works by logging metadata blocks to the journal. In fast commit
+mode, Ext4 only stores the minimal delta needed to recreate the
+affected metadata in fast commit space that is shared with JBD2.
+Once the fast commit area fills in or if fast commit is not possible
+or if JBD2 commit timer goes off, Ext4 performs a traditional full commit.
+A full commit invalidates all the fast commits that happened before
+it and thus it makes the fast commit area empty for further fast
+commits. This feature needs to be enabled at mkfs time.
+
 The journal inode is typically inode 8. The first 68 bytes of the
 journal inode are replicated in the ext4 superblock. The journal itself
 is normal (but hidden) file within the filesystem. The file usually
···
      - \_\_be32
      - h\_commit\_nsec
      - Nanoseconds component of the above timestamp.
+
+Fast commits
+~~~~~~~~~~~~
+
+Fast commit area is organized as a log of tag length values. Each TLV has
+a ``struct ext4_fc_tl`` in the beginning which stores the tag and the length
+of the entire field. It is followed by variable length tag specific value.
+Here is the list of supported tags and their meanings:
+
+.. list-table::
+   :widths: 8 20 20 32
+   :header-rows: 1
+
+   * - Tag
+     - Meaning
+     - Value struct
+     - Description
+   * - EXT4_FC_TAG_HEAD
+     - Fast commit area header
+     - ``struct ext4_fc_head``
+     - Stores the TID of the transaction after which these fast commits should
+       be applied.
+   * - EXT4_FC_TAG_ADD_RANGE
+     - Add extent to inode
+     - ``struct ext4_fc_add_range``
+     - Stores the inode number and extent to be added in this inode
+   * - EXT4_FC_TAG_DEL_RANGE
+     - Remove logical offsets to inode
+     - ``struct ext4_fc_del_range``
+     - Stores the inode number and the logical offset range that needs to be
+       removed
+   * - EXT4_FC_TAG_CREAT
+     - Create directory entry for a newly created file
+     - ``struct ext4_fc_dentry_info``
+     - Stores the parent inode number, inode number and directory entry of the
+       newly created file
+   * - EXT4_FC_TAG_LINK
+     - Link a directory entry to an inode
+     - ``struct ext4_fc_dentry_info``
+     - Stores the parent inode number, inode number and directory entry
+   * - EXT4_FC_TAG_UNLINK
+     - Unlink a directory entry of an inode
+     - ``struct ext4_fc_dentry_info``
+     - Stores the parent inode number, inode number and directory entry
+
+   * - EXT4_FC_TAG_PAD
+     - Padding (unused area)
+     - None
+     - Unused bytes in the fast commit area.
+
+   * - EXT4_FC_TAG_TAIL
+     - Mark the end of a fast commit
+     - ``struct ext4_fc_tail``
+     - Stores the TID of the commit, CRC of the fast commit of which this tag
+       represents the end of
 

Documentation/filesystems/journalling.rst

···
 if you allow unprivileged userspace to trigger codepaths containing
 these calls.
 
+Fast commits
+~~~~~~~~~~~~
+
+JBD2 to also allows you to perform file-system specific delta commits known as
+fast commits. In order to use fast commits, you first need to call
+:c:func:`jbd2_fc_init` and tell how many blocks at the end of journal
+area should be reserved for fast commits. Along with that, you will also need
+to set following callbacks that perform correspodning work:
+
+`journal->j_fc_cleanup_cb`: Cleanup function called after every full commit and
+fast commit.
+
+`journal->j_fc_replay_cb`: Replay function called for replay of fast commit
+blocks.
+
+File system is free to perform fast commits as and when it wants as long as it
+gets permission from JBD2 to do so by calling the function
+:c:func:`jbd2_fc_begin_commit()`. Once a fast commit is done, the client
+file  system should tell JBD2 about it by calling
+:c:func:`jbd2_fc_end_commit()`. If file system wants JBD2 to perform a full
+commit immediately after stopping the fast commit it can do so by calling
+:c:func:`jbd2_fc_end_commit_fallback()`. This is useful if fast commit operation
+fails for some reason and the only way to guarantee consistency is for JBD2 to
+perform the full traditional commit.
+
+JBD2 helper functions to manage fast commit buffers. File system can use
+:c:func:`jbd2_fc_get_buf()` and :c:func:`jbd2_fc_wait_bufs()` to allocate
+and wait on IO completion of fast commit buffers.
+
+Currently, only Ext4 implements fast commits. For details of its implementation
+of fast commits, please refer to the top level comments in
+fs/ext4/fast_commit.c.
+
 Summary
 ~~~~~~~
 

fs/ext4/Makefile

···
 		indirect.o inline.o inode.o ioctl.o mballoc.o migrate.o \
 		mmp.o move_extent.o namei.o page-io.o readpage.o resize.o \
 		super.o symlink.o sysfs.o xattr.o xattr_hurd.o xattr_trusted.o \
-		xattr_user.o
+		xattr_user.o fast_commit.o
 
 ext4-$(CONFIG_EXT4_FS_POSIX_ACL)	+= acl.o
 ext4-$(CONFIG_EXT4_FS_SECURITY)		+= xattr_security.o

fs/ext4/acl.c

···
 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
+	ext4_fc_start_update(inode);
 
 	if ((type == ACL_TYPE_ACCESS) && acl) {
 		error = posix_acl_update_mode(inode, &mode, &acl);
···
 	}
 out_stop:
 	ext4_journal_stop(handle);
+	ext4_fc_stop_update(inode);
 	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
 		goto retry;
 	return error;

fs/ext4/balloc.c

···
 				      struct buffer_head *bh)
 {
 	ext4_fsblk_t	blk;
-	struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
+	struct ext4_group_info *grp;
+
+	if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
+
+	grp = ext4_get_group_info(sb, block_group);
 
 	if (buffer_verified(bh))
 		return 0;
···
 	 */
 	set_buffer_new(bh);
 	trace_ext4_read_block_bitmap_load(sb, block_group, ignore_locked);
-	bh->b_end_io = ext4_end_bitmap_read;
-	get_bh(bh);
-	submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO |
-		  (ignore_locked ? REQ_RAHEAD : 0), bh);
+	ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO |
+			    (ignore_locked ? REQ_RAHEAD : 0),
+			    ext4_end_bitmap_read);
 	return bh;
 verify:
 	err = ext4_validate_block_bitmap(sb, desc, block_group, bh);

fs/ext4/block_validity.c

···
 
 	printk(KERN_INFO "System zones: ");
 	rcu_read_lock();
-	system_blks = rcu_dereference(sbi->system_blks);
+	system_blks = rcu_dereference(sbi->s_system_blks);
 	node = rb_first(&system_blks->root);
 	while (node) {
 		entry = rb_entry(node, struct ext4_system_zone, node);
···
 	 * with ext4_data_block_valid() accessing the rbtree at the same
 	 * time.
 	 */
-	rcu_assign_pointer(sbi->system_blks, system_blks);
+	rcu_assign_pointer(sbi->s_system_blks, system_blks);
 
 	if (test_opt(sb, DEBUG))
 		debug_print_tree(sbi);
···
 {
 	struct ext4_system_blocks *system_blks;
 
-	system_blks = rcu_dereference_protected(EXT4_SB(sb)->system_blks,
+	system_blks = rcu_dereference_protected(EXT4_SB(sb)->s_system_blks,
 					lockdep_is_held(&sb->s_umount));
-	rcu_assign_pointer(EXT4_SB(sb)->system_blks, NULL);
+	rcu_assign_pointer(EXT4_SB(sb)->s_system_blks, NULL);
 
 	if (system_blks)
 		call_rcu(&system_blks->rcu, ext4_destroy_system_zone);
···
 	 * mount option.
 	 */
 	rcu_read_lock();
-	system_blks = rcu_dereference(sbi->system_blks);
+	system_blks = rcu_dereference(sbi->s_system_blks);
 	if (system_blks == NULL)
 		goto out_rcu;
 

fs/ext4/dir.c

···
 {
 	struct qstr qstr = {.name = str, .len = len };
 	const struct dentry *parent = READ_ONCE(dentry->d_parent);
-	const struct inode *inode = READ_ONCE(parent->d_inode);
+	const struct inode *inode = d_inode_rcu(parent);
 	char strbuf[DNAME_INLINE_LEN];
 
 	if (!inode || !IS_CASEFOLDED(inode) ||
···
 {
 	const struct ext4_sb_info *sbi = EXT4_SB(dentry->d_sb);
 	const struct unicode_map *um = sbi->s_encoding;
-	const struct inode *inode = READ_ONCE(dentry->d_inode);
+	const struct inode *inode = d_inode_rcu(dentry);
 	unsigned char *norm;
 	int len, ret = 0;
 

fs/ext4/ext4.h

···
 #include <linux/seqlock.h>
 #include <linux/mutex.h>
 #include <linux/timer.h>
-#include <linux/version.h>
 #include <linux/wait.h>
 #include <linux/sched/signal.h>
 #include <linux/blockgroup_lock.h>
···
 
 /* Flags which are mutually exclusive to DAX */
 #define EXT4_DAX_MUT_EXCL (EXT4_VERITY_FL | EXT4_ENCRYPT_FL |\
-			   EXT4_JOURNAL_DATA_FL)
+			   EXT4_JOURNAL_DATA_FL | EXT4_INLINE_DATA_FL)
 
 /* Mask out flags that are inappropriate for the given type of inode. */
 static inline __u32 ext4_mask_flags(umode_t mode, __u32 flags)
···
 #endif /* defined(__KERNEL__) || defined(__linux__) */
 
 #include "extents_status.h"
+#include "fast_commit.h"
 
 /*
  * Lock subclasses for i_data_sem in the ext4_inode_info structure.
···
 	struct rw_semaphore xattr_sem;
 
 	struct list_head i_orphan;	/* unlinked but open inodes */
+
+	/* Fast commit related info */
+
+	struct list_head i_fc_list;	/*
+					 * inodes that need fast commit
+					 * protected by sbi->s_fc_lock.
+					 */
+
+	/* Fast commit subtid when this inode was committed */
+	unsigned int i_fc_committed_subtid;
+
+	/* Start of lblk range that needs to be committed in this fast commit */
+	ext4_lblk_t i_fc_lblk_start;
+
+	/* End of lblk range that needs to be committed in this fast commit */
+	ext4_lblk_t i_fc_lblk_len;
+
+	/* Number of ongoing updates on this inode */
+	atomic_t  i_fc_updates;
+
+	/* Fast commit wait queue for this inode */
+	wait_queue_head_t i_fc_wait;
+
+	/* Protect concurrent accesses on i_fc_lblk_start, i_fc_lblk_len */
+	struct mutex i_fc_lock;
 
 	/*
 	 * i_disksize keeps track of what the inode size is ON DISK, not
···
 #define	EXT4_VALID_FS			0x0001	/* Unmounted cleanly */
 #define	EXT4_ERROR_FS			0x0002	/* Errors detected */
 #define	EXT4_ORPHAN_FS			0x0004	/* Orphans being recovered */
+#define EXT4_FC_INELIGIBLE		0x0008	/* Fast commit ineligible */
+#define EXT4_FC_COMMITTING		0x0010	/* File system underoing a fast
+						 * commit.
+						 */
+#define EXT4_FC_REPLAY			0x0020	/* Fast commit replay ongoing */
 
 /*
  * Misc. filesystem flags
···
 
 #define EXT4_MOUNT2_EXPLICIT_JOURNAL_CHECKSUM	0x00000008 /* User explicitly
 						specified journal checksum */
+
+#define EXT4_MOUNT2_JOURNAL_FAST_COMMIT	0x00000010 /* Journal fast commit */
 
 #define clear_opt(sb, opt)		EXT4_SB(sb)->s_mount_opt &= \
 						~EXT4_MOUNT_##opt
···
 	unsigned long s_commit_interval;
 	u32 s_max_batch_time;
 	u32 s_min_batch_time;
-	struct block_device *journal_bdev;
+	struct block_device *s_journal_bdev;
 #ifdef CONFIG_QUOTA
 	/* Names of quota files with journalled quota */
 	char __rcu *s_qf_names[EXT4_MAXQUOTAS];
 	int s_jquota_fmt;			/* Format of quota to use */
 #endif
 	unsigned int s_want_extra_isize; /* New inodes should reserve # bytes */
-	struct ext4_system_blocks __rcu *system_blks;
+	struct ext4_system_blocks __rcu *s_system_blks;
 
 #ifdef EXTENTS_STATS
 	/* ext4 extents stats */
···
 	/* Record the errseq of the backing block device */
 	errseq_t s_bdev_wb_err;
 	spinlock_t s_bdev_wb_lock;
+
+	/* Ext4 fast commit stuff */
+	atomic_t s_fc_subtid;
+	atomic_t s_fc_ineligible_updates;
+	/*
+	 * After commit starts, the main queue gets locked, and the further
+	 * updates get added in the staging queue.
+	 */
+#define FC_Q_MAIN	0
+#define FC_Q_STAGING	1
+	struct list_head s_fc_q[2];	/* Inodes staged for fast commit
+					 * that have data changes in them.
+					 */
+	struct list_head s_fc_dentry_q[2];	/* directory entry updates */
+	unsigned int s_fc_bytes;
+	/*
+	 * Main fast commit lock. This lock protects accesses to the
+	 * following fields:
+	 * ei->i_fc_list, s_fc_dentry_q, s_fc_q, s_fc_bytes, s_fc_bh.
+	 */
+	spinlock_t s_fc_lock;
+	struct buffer_head *s_fc_bh;
+	struct ext4_fc_stats s_fc_stats;
+	u64 s_fc_avg_commit_time;
+#ifdef CONFIG_EXT4_DEBUG
+	int s_fc_debug_max_replay;
+#endif
+	struct ext4_fc_replay_state s_fc_replay_state;
 };
 
 static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)
···
 	EXT4_STATE_EXT_PRECACHED,	/* extents have been precached */
 	EXT4_STATE_LUSTRE_EA_INODE,	/* Lustre-style ea_inode */
 	EXT4_STATE_VERITY_IN_PROGRESS,	/* building fs-verity Merkle tree */
+	EXT4_STATE_FC_COMMITTING,	/* Fast commit ongoing */
 };
 
 #define EXT4_INODE_BIT_FNS(name, field, offset)				\
···
 #define EXT4_FEATURE_COMPAT_RESIZE_INODE	0x0010
 #define EXT4_FEATURE_COMPAT_DIR_INDEX		0x0020
 #define EXT4_FEATURE_COMPAT_SPARSE_SUPER2	0x0200
+#define EXT4_FEATURE_COMPAT_FAST_COMMIT		0x0400
 #define EXT4_FEATURE_COMPAT_STABLE_INODES	0x0800
 
 #define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
···
 EXT4_FEATURE_COMPAT_FUNCS(resize_inode,		RESIZE_INODE)
 EXT4_FEATURE_COMPAT_FUNCS(dir_index,		DIR_INDEX)
 EXT4_FEATURE_COMPAT_FUNCS(sparse_super2,	SPARSE_SUPER2)
+EXT4_FEATURE_COMPAT_FUNCS(fast_commit,		FAST_COMMIT)
 EXT4_FEATURE_COMPAT_FUNCS(stable_inodes,	STABLE_INODES)
 
 EXT4_FEATURE_RO_COMPAT_FUNCS(sparse_super,	SPARSE_SUPER)
···
 			  struct dx_hash_info *hinfo);
 
 /* ialloc.c */
+extern int ext4_mark_inode_used(struct super_block *sb, int ino);
 extern struct inode *__ext4_new_inode(handle_t *, struct inode *, umode_t,
 				      const struct qstr *qstr, __u32 goal,
 				      uid_t *owner, __u32 i_flags,
···
 extern int ext4_init_inode_table(struct super_block *sb,
 				 ext4_group_t group, int barrier);
 extern void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate);
+
+/* fast_commit.c */
+int ext4_fc_info_show(struct seq_file *seq, void *v);
+void ext4_fc_init(struct super_block *sb, journal_t *journal);
+void ext4_fc_init_inode(struct inode *inode);
+void ext4_fc_track_range(struct inode *inode, ext4_lblk_t start,
+			 ext4_lblk_t end);
+void ext4_fc_track_unlink(struct inode *inode, struct dentry *dentry);
+void ext4_fc_track_link(struct inode *inode, struct dentry *dentry);
+void ext4_fc_track_create(struct inode *inode, struct dentry *dentry);
+void ext4_fc_track_inode(struct inode *inode);
+void ext4_fc_mark_ineligible(struct super_block *sb, int reason);
+void ext4_fc_start_ineligible(struct super_block *sb, int reason);
+void ext4_fc_stop_ineligible(struct super_block *sb);
+void ext4_fc_start_update(struct inode *inode);
+void ext4_fc_stop_update(struct inode *inode);
+void ext4_fc_del(struct inode *inode);
+bool ext4_fc_replay_check_excluded(struct super_block *sb, ext4_fsblk_t block);
+void ext4_fc_replay_cleanup(struct super_block *sb);
+int ext4_fc_commit(journal_t *journal, tid_t commit_tid);
+int __init ext4_fc_init_dentry_cache(void);
 
 /* mballoc.c */
 extern const struct seq_operations ext4_mb_seq_groups_ops;
···
 				ext4_fsblk_t block, unsigned long count);
 extern int ext4_trim_fs(struct super_block *, struct fstrim_range *);
 extern void ext4_process_freed_data(struct super_block *sb, tid_t commit_tid);
+extern void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
+		       int len, int state);
 
 /* inode.c */
+void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
+			 struct ext4_inode_info *ei);
 int ext4_inode_is_fast_symlink(struct inode *inode);
 struct buffer_head *ext4_getblk(handle_t *, struct inode *, ext4_lblk_t, int);
 struct buffer_head *ext4_bread(handle_t *, struct inode *, ext4_lblk_t, int);
···
 extern void ext4_dirty_inode(struct inode *, int);
 extern int ext4_change_inode_journal_flag(struct inode *, int);
 extern int ext4_get_inode_loc(struct inode *, struct ext4_iloc *);
+extern int ext4_get_fc_inode_loc(struct super_block *sb, unsigned long ino,
+			  struct ext4_iloc *iloc);
 extern int ext4_inode_attach_jinode(struct inode *inode);
 extern int ext4_can_truncate(struct inode *inode);
 extern int ext4_truncate(struct inode *);
···
 /* ioctl.c */
 extern long ext4_ioctl(struct file *, unsigned int, unsigned long);
 extern long ext4_compat_ioctl(struct file *, unsigned int, unsigned long);
+extern void ext4_reset_inode_seed(struct inode *inode);
 
 /* migrate.c */
 extern int ext4_ext_migrate(struct inode *);
 extern int ext4_ind_migrate(struct inode *inode);
 
 /* namei.c */
+extern int ext4_init_new_dir(handle_t *handle, struct inode *dir,
+			     struct inode *inode);
 extern int ext4_dirblock_csum_verify(struct inode *inode,
 				     struct buffer_head *bh);
 extern int ext4_orphan_add(handle_t *, struct inode *);
···
 /* super.c */
 extern struct buffer_head *ext4_sb_bread(struct super_block *sb,
 					 sector_t block, int op_flags);
+extern struct buffer_head *ext4_sb_bread_unmovable(struct super_block *sb,
+						   sector_t block);
+extern void ext4_read_bh_nowait(struct buffer_head *bh, int op_flags,
+				bh_end_io_t *end_io);
+extern int ext4_read_bh(struct buffer_head *bh, int op_flags,
+			bh_end_io_t *end_io);
+extern int ext4_read_bh_lock(struct buffer_head *bh, int op_flags, bool wait);
+extern void ext4_sb_breadahead_unmovable(struct super_block *sb, sector_t block);
 extern int ext4_seq_options_show(struct seq_file *seq, void *offset);
 extern int ext4_calculate_overhead(struct super_block *sb);
 extern void ext4_superblock_csum_set(struct super_block *sb);
···
 	return ext4_has_feature_gdt_csum(sb) || ext4_has_metadata_csum(sb);
 }
 
+#define ext4_read_incompat_64bit_val(es, name) \
+	(((es)->s_feature_incompat & cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT) \
+		? (ext4_fsblk_t)le32_to_cpu(es->name##_hi) << 32 : 0) | \
+		le32_to_cpu(es->name##_lo))
+
 static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
 {
-	return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |
-		le32_to_cpu(es->s_blocks_count_lo);
+	return ext4_read_incompat_64bit_val(es, s_blocks_count);
 }
 
 static inline ext4_fsblk_t ext4_r_blocks_count(struct ext4_super_block *es)
 {
-	return ((ext4_fsblk_t)le32_to_cpu(es->s_r_blocks_count_hi) << 32) |
-		le32_to_cpu(es->s_r_blocks_count_lo);
+	return ext4_read_incompat_64bit_val(es, s_r_blocks_count);
 }
 
 static inline ext4_fsblk_t ext4_free_blocks_count(struct ext4_super_block *es)
 {
-	return ((ext4_fsblk_t)le32_to_cpu(es->s_free_blocks_count_hi) << 32) |
-		le32_to_cpu(es->s_free_blocks_count_lo);
+	return ext4_read_incompat_64bit_val(es, s_free_blocks_count);
 }
 
 static inline void ext4_blocks_count_set(struct ext4_super_block *es,
···
 
 struct ext4_group_info {
 	unsigned long   bb_state;
+#ifdef AGGRESSIVE_CHECK
+	unsigned long	bb_check_counter;
+#endif
 	struct rb_root  bb_free_root;
 	ext4_grpblk_t	bb_first_free;	/* first free block */
 	ext4_grpblk_t	bb_free;	/* total free blocks */
···
 extern int ext4_ci_compare(const struct inode *parent,
 			   const struct qstr *fname,
 			   const struct qstr *entry, bool quick);
+extern int __ext4_unlink(struct inode *dir, const struct qstr *d_name,
+			 struct inode *inode);
+extern int __ext4_link(struct inode *dir, struct inode *inode,
+		       struct dentry *dentry);
 
 #define S_SHIFT 12
 static const unsigned char ext4_type_by_mode[(S_IFMT >> S_SHIFT) + 1] = {
···
 extern int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode,
 				       int check_cred, int restart_cred,
 				       int revoke_cred);
+extern void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end);
+extern int ext4_ext_replay_set_iblocks(struct inode *inode);
+extern int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
+		int len, int unwritten, ext4_fsblk_t pblk);
+extern int ext4_ext_clear_bb(struct inode *inode);
 
 
 /* move_extent.c */

fs/ext4/ext4_jbd2.c

···
 		return ERR_PTR(err);
 
 	journal = EXT4_SB(sb)->s_journal;
-	if (!journal)
+	if (!journal || (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))
 		return ext4_get_nojournal();
 	return jbd2__journal_start(journal, blocks, rsv_blocks, revoke_creds,
 				   GFP_NOFS, type, line);

fs/ext4/extents.c

···
 
 	if (!bh_uptodate_or_lock(bh)) {
 		trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
-		err = bh_submit_read(bh);
+		err = ext4_read_bh(bh, 0, NULL);
 		if (err < 0)
 			goto errout;
 	}
···
 	err = ext4_ext_dirty(handle, inode, path + path->p_depth);
 out:
 	ext4_ext_show_leaf(inode, path);
+	ext4_fc_track_range(inode, ee_block, ee_block + ee_len - 1);
 	return err;
 }
 
···
 	if (*allocated > map->m_len)
 		*allocated = map->m_len;
 	map->m_len = *allocated;
+	ext4_fc_track_range(inode, ee_block, ee_block + ee_len - 1);
 	return 0;
 }
 
···
  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
  *
- * return > 0, number of of blocks already mapped/allocated
+ * return > 0, number of blocks already mapped/allocated
  *          if create == 0 and these are pre-allocated blocks
  *          	buffer head is unmapped
  *          otherwise blocks are mapped
···
 	map->m_len = ar.len;
 	allocated = map->m_len;
 	ext4_ext_show_leaf(inode, path);
-
+	ext4_fc_track_range(inode, map->m_lblk, map->m_lblk + map->m_len - 1);
 out:
 	ext4_ext_drop_refs(path);
 	kfree(path);
···
 	ret = ext4_mark_inode_dirty(handle, inode);
 	if (unlikely(ret))
 		goto out_handle;
-
+	ext4_fc_track_range(inode, offset >> inode->i_sb->s_blocksize_bits,
+			(offset + len - 1) >> inode->i_sb->s_blocksize_bits);
 	/* Zero out partial block at the edges of the range */
 	ret = ext4_zero_partial_blocks(handle, inode, offset, len);
 	if (ret >= 0)
···
 		     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
 		     FALLOC_FL_INSERT_RANGE))
 		return -EOPNOTSUPP;
+	ext4_fc_track_range(inode, offset >> blkbits,
+			(offset + len - 1) >> blkbits);
 
-	if (mode & FALLOC_FL_PUNCH_HOLE)
-		return ext4_punch_hole(inode, offset, len);
+	ext4_fc_start_update(inode);
+
+	if (mode & FALLOC_FL_PUNCH_HOLE) {
+		ret = ext4_punch_hole(inode, offset, len);
+		goto exit;
+	}
 
 	ret = ext4_convert_inline_data(inode);
 	if (ret)
-		return ret;
+		goto exit;
 
-	if (mode & FALLOC_FL_COLLAPSE_RANGE)
-		return ext4_collapse_range(inode, offset, len);
+	if (mode & FALLOC_FL_COLLAPSE_RANGE) {
+		ret = ext4_collapse_range(inode, offset, len);
+		goto exit;
+	}
 
-	if (mode & FALLOC_FL_INSERT_RANGE)
-		return ext4_insert_range(inode, offset, len);
+	if (mode & FALLOC_FL_INSERT_RANGE) {
+		ret = ext4_insert_range(inode, offset, len);
+		goto exit;
+	}
 
-	if (mode & FALLOC_FL_ZERO_RANGE)
-		return ext4_zero_range(file, offset, len, mode);
-
+	if (mode & FALLOC_FL_ZERO_RANGE) {
+		ret = ext4_zero_range(file, offset, len, mode);
+		goto exit;
+	}
 	trace_ext4_fallocate_enter(inode, offset, len, mode);
 	lblk = offset >> blkbits;
 
···
 		goto out;
 
 	if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
-		ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
-						EXT4_I(inode)->i_sync_tid);
+		ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
+					EXT4_I(inode)->i_sync_tid);
 	}
 out:
 	inode_unlock(inode);
 	trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
+exit:
+	ext4_fc_stop_update(inode);
 	return ret;
 }
 
···
 
 int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
 {
-	int ret, err = 0;
+	int ret = 0, err = 0;
 	struct ext4_io_end_vec *io_end_vec;
 
 	/*
···
 		ret = PTR_ERR(handle);
 		goto out_mmap;
 	}
+	ext4_fc_start_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE);
 
 	down_write(&EXT4_I(inode)->i_data_sem);
 	ext4_discard_preallocations(inode, 0);
···
 
 out_stop:
 	ext4_journal_stop(handle);
+	ext4_fc_stop_ineligible(sb);
 out_mmap:
 	up_write(&EXT4_I(inode)->i_mmap_sem);
 out_mutex:
···
 		ret = PTR_ERR(handle);
 		goto out_mmap;
 	}
+	ext4_fc_start_ineligible(sb, EXT4_FC_REASON_FALLOC_RANGE);
 
 	/* Expand file to avoid data loss if there is error while shifting */
 	inode->i_size += len;
···
 
 out_stop:
 	ext4_journal_stop(handle);
+	ext4_fc_stop_ineligible(sb);
 out_mmap:
 	up_write(&EXT4_I(inode)->i_mmap_sem);
 out_mutex:
···
 	kfree(path);
 
 	return err ? err : mapped;
+}
+
+/*
+ * Updates physical block address and unwritten status of extent
+ * starting at lblk start and of len. If such an extent doesn't exist,
+ * this function splits the extent tree appropriately to create an
+ * extent like this.  This function is called in the fast commit
+ * replay path.  Returns 0 on success and error on failure.
+ */
+int ext4_ext_replay_update_ex(struct inode *inode, ext4_lblk_t start,
+			      int len, int unwritten, ext4_fsblk_t pblk)
+{
+	struct ext4_ext_path *path = NULL, *ppath;
+	struct ext4_extent *ex;
+	int ret;
+
+	path = ext4_find_extent(inode, start, NULL, 0);
+	if (!path)
+		return -EINVAL;
+	ex = path[path->p_depth].p_ext;
+	if (!ex) {
+		ret = -EFSCORRUPTED;
+		goto out;
+	}
+
+	if (le32_to_cpu(ex->ee_block) != start ||
+		ext4_ext_get_actual_len(ex) != len) {
+		/* We need to split this extent to match our extent first */
+		ppath = path;
+		down_write(&EXT4_I(inode)->i_data_sem);
+		ret = ext4_force_split_extent_at(NULL, inode, &ppath, start, 1);
+		up_write(&EXT4_I(inode)->i_data_sem);
+		if (ret)
+			goto out;
+		kfree(path);
+		path = ext4_find_extent(inode, start, NULL, 0);
+		if (IS_ERR(path))
+			return -1;
+		ppath = path;
+		ex = path[path->p_depth].p_ext;
+		WARN_ON(le32_to_cpu(ex->ee_block) != start);
+		if (ext4_ext_get_actual_len(ex) != len) {
+			down_write(&EXT4_I(inode)->i_data_sem);
+			ret = ext4_force_split_extent_at(NULL, inode, &ppath,
+							 start + len, 1);
+			up_write(&EXT4_I(inode)->i_data_sem);
+			if (ret)
+				goto out;
+			kfree(path);
+			path = ext4_find_extent(inode, start, NULL, 0);
+			if (IS_ERR(path))
+				return -EINVAL;
+			ex = path[path->p_depth].p_ext;
+		}
+	}
+	if (unwritten)
+		ext4_ext_mark_unwritten(ex);
+	else
+		ext4_ext_mark_initialized(ex);
+	ext4_ext_store_pblock(ex, pblk);
+	down_write(&EXT4_I(inode)->i_data_sem);
+	ret = ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
+	up_write(&EXT4_I(inode)->i_data_sem);
+out:
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	ext4_mark_inode_dirty(NULL, inode);
+	return ret;
+}
+
+/* Try to shrink the extent tree */
+void ext4_ext_replay_shrink_inode(struct inode *inode, ext4_lblk_t end)
+{
+	struct ext4_ext_path *path = NULL;
+	struct ext4_extent *ex;
+	ext4_lblk_t old_cur, cur = 0;
+
+	while (cur < end) {
+		path = ext4_find_extent(inode, cur, NULL, 0);
+		if (IS_ERR(path))
+			return;
+		ex = path[path->p_depth].p_ext;
+		if (!ex) {
+			ext4_ext_drop_refs(path);
+			kfree(path);
+			ext4_mark_inode_dirty(NULL, inode);
+			return;
+		}
+		old_cur = cur;
+		cur = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
+		if (cur <= old_cur)
+			cur = old_cur + 1;
+		ext4_ext_try_to_merge(NULL, inode, path, ex);
+		down_write(&EXT4_I(inode)->i_data_sem);
+		ext4_ext_dirty(NULL, inode, &path[path->p_depth]);
+		up_write(&EXT4_I(inode)->i_data_sem);
+		ext4_mark_inode_dirty(NULL, inode);
+		ext4_ext_drop_refs(path);
+		kfree(path);
+	}
+}
+
+/* Check if *cur is a hole and if it is, skip it */
+static void skip_hole(struct inode *inode, ext4_lblk_t *cur)
+{
+	int ret;
+	struct ext4_map_blocks map;
+
+	map.m_lblk = *cur;
+	map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
+
+	ret = ext4_map_blocks(NULL, inode, &map, 0);
+	if (ret != 0)
+		return;
+	*cur = *cur + map.m_len;
+}
+
+/* Count number of blocks used by this inode and update i_blocks */
+int ext4_ext_replay_set_iblocks(struct inode *inode)
+{
+	struct ext4_ext_path *path = NULL, *path2 = NULL;
+	struct ext4_extent *ex;
+	ext4_lblk_t cur = 0, end;
+	int numblks = 0, i, ret = 0;
+	ext4_fsblk_t cmp1, cmp2;
+	struct ext4_map_blocks map;
+
+	/* Determin the size of the file first */
+	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
+					EXT4_EX_NOCACHE);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+	ex = path[path->p_depth].p_ext;
+	if (!ex) {
+		ext4_ext_drop_refs(path);
+		kfree(path);
+		goto out;
+	}
+	end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
+	ext4_ext_drop_refs(path);
+	kfree(path);
+
+	/* Count the number of data blocks */
+	cur = 0;
+	while (cur < end) {
+		map.m_lblk = cur;
+		map.m_len = end - cur;
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+		if (ret < 0)
+			break;
+		if (ret > 0)
+			numblks += ret;
+		cur = cur + map.m_len;
+	}
+
+	/*
+	 * Count the number of extent tree blocks. We do it by looking up
+	 * two successive extents and determining the difference between
+	 * their paths. When path is different for 2 successive extents
+	 * we compare the blocks in the path at each level and increment
+	 * iblocks by total number of differences found.
+	 */
+	cur = 0;
+	skip_hole(inode, &cur);
+	path = ext4_find_extent(inode, cur, NULL, 0);
+	if (IS_ERR(path))
+		goto out;
+	numblks += path->p_depth;
+	ext4_ext_drop_refs(path);
+	kfree(path);
+	while (cur < end) {
+		path = ext4_find_extent(inode, cur, NULL, 0);
+		if (IS_ERR(path))
+			break;
+		ex = path[path->p_depth].p_ext;
+		if (!ex) {
+			ext4_ext_drop_refs(path);
+			kfree(path);
+			return 0;
+		}
+		cur = max(cur + 1, le32_to_cpu(ex->ee_block) +
+					ext4_ext_get_actual_len(ex));
+		skip_hole(inode, &cur);
+
+		path2 = ext4_find_extent(inode, cur, NULL, 0);
+		if (IS_ERR(path2)) {
+			ext4_ext_drop_refs(path);
+			kfree(path);
+			break;
+		}
+		ex = path2[path2->p_depth].p_ext;
+		for (i = 0; i <= max(path->p_depth, path2->p_depth); i++) {
+			cmp1 = cmp2 = 0;
+			if (i <= path->p_depth)
+				cmp1 = path[i].p_bh ?
+					path[i].p_bh->b_blocknr : 0;
+			if (i <= path2->p_depth)
+				cmp2 = path2[i].p_bh ?
+					path2[i].p_bh->b_blocknr : 0;
+			if (cmp1 != cmp2 && cmp2 != 0)
+				numblks++;
+		}
+		ext4_ext_drop_refs(path);
+		ext4_ext_drop_refs(path2);
+		kfree(path);
+		kfree(path2);
+	}
+
+out:
+	inode->i_blocks = numblks << (inode->i_sb->s_blocksize_bits - 9);
+	ext4_mark_inode_dirty(NULL, inode);
+	return 0;
+}
+
+int ext4_ext_clear_bb(struct inode *inode)
+{
+	struct ext4_ext_path *path = NULL;
+	struct ext4_extent *ex;
+	ext4_lblk_t cur = 0, end;
+	int j, ret = 0;
+	struct ext4_map_blocks map;
+
+	/* Determin the size of the file first */
+	path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
+					EXT4_EX_NOCACHE);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+	ex = path[path->p_depth].p_ext;
+	if (!ex) {
+		ext4_ext_drop_refs(path);
+		kfree(path);
+		return 0;
+	}
+	end = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
+	ext4_ext_drop_refs(path);
+	kfree(path);
+
+	cur = 0;
+	while (cur < end) {
+		map.m_lblk = cur;
+		map.m_len = end - cur;
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+		if (ret < 0)
+			break;
+		if (ret > 0) {
+			path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
+			if (!IS_ERR_OR_NULL(path)) {
+				for (j = 0; j < path->p_depth; j++) {
+
+					ext4_mb_mark_bb(inode->i_sb,
+							path[j].p_block, 1, 0);
+				}
+				ext4_ext_drop_refs(path);
+				kfree(path);
+			}
+			ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
+		}
+		cur = cur + map.m_len;
+	}
+
+	return 0;
 }

fs/ext4/extents_status.c

···
 			       ext4_lblk_t lblk, ext4_lblk_t end,
 			       struct extent_status *es)
 {
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return;
+
 	trace_ext4_es_find_extent_range_enter(inode, lblk);
 
 	read_lock(&EXT4_I(inode)->i_es_lock);
···
 {
 	bool ret;
 
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return false;
+
 	read_lock(&EXT4_I(inode)->i_es_lock);
 	ret = __es_scan_range(inode, matching_fn, lblk, end);
 	read_unlock(&EXT4_I(inode)->i_es_lock);
···
 		      ext4_lblk_t lblk)
 {
 	bool ret;
+
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return false;
 
 	read_lock(&EXT4_I(inode)->i_es_lock);
 	ret = __es_scan_clu(inode, matching_fn, lblk);
···
 	int err = 0;
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
+
 	es_debug("add [%u/%u) %llu %x to extent status tree of inode %lu\n",
 		 lblk, len, pblk, status, inode->i_ino);
 
···
 	struct extent_status newes;
 	ext4_lblk_t end = lblk + len - 1;
 
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return;
+
 	newes.es_lblk = lblk;
 	newes.es_len = len;
 	ext4_es_store_pblock_status(&newes, pblk, status);
···
 	struct extent_status *es1 = NULL;
 	struct rb_node *node;
 	int found = 0;
+
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
 
 	trace_ext4_es_lookup_extent_enter(inode, lblk);
 	es_debug("lookup extent in block %u\n", lblk);
···
 	ext4_lblk_t end;
 	int err = 0;
 	int reserved = 0;
+
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
 
 	trace_ext4_es_remove_extent(inode, lblk, len);
 	es_debug("remove [%u/%u) from extent status tree of inode %lu\n",
···
 {
 	struct extent_status newes;
 	int err = 0;
+
+	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
 
 	es_debug("add [%u/1) delayed to extent status tree of inode %lu\n",
 		 lblk, inode->i_ino);

fs/ext4/fast_commit.c

···
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * fs/ext4/fast_commit.c
+ *
+ * Written by Harshad Shirwadkar <[e-mail]>
+ *
+ * Ext4 fast commits routines.
+ */
+#include "ext4.h"
+#include "ext4_jbd2.h"
+#include "ext4_extents.h"
+#include "mballoc.h"
+
+/*
+ * Ext4 Fast Commits
+ * -----------------
+ *
+ * Ext4 fast commits implement fine grained journalling for Ext4.
+ *
+ * Fast commits are organized as a log of tag-length-value (TLV) structs. (See
+ * struct ext4_fc_tl). Each TLV contains some delta that is replayed TLV by
+ * TLV during the recovery phase. For the scenarios for which we currently
+ * don't have replay code, fast commit falls back to full commits.
+ * Fast commits record delta in one of the following three categories.
+ *
+ * (A) Directory entry updates:
+ *
+ * - EXT4_FC_TAG_UNLINK		- records directory entry unlink
+ * - EXT4_FC_TAG_LINK		- records directory entry link
+ * - EXT4_FC_TAG_CREAT		- records inode and directory entry creation
+ *
+ * (B) File specific data range updates:
+ *
+ * - EXT4_FC_TAG_ADD_RANGE	- records addition of new blocks to an inode
+ * - EXT4_FC_TAG_DEL_RANGE	- records deletion of blocks from an inode
+ *
+ * (C) Inode metadata (mtime / ctime etc):
+ *
+ * - EXT4_FC_TAG_INODE		- record the inode that should be replayed
+ *				  during recovery. Note that iblocks field is
+ *				  not replayed and instead derived during
+ *				  replay.
+ * Commit Operation
+ * ----------------
+ * With fast commits, we maintain all the directory entry operations in the
+ * order in which they are issued in an in-memory queue. This queue is flushed
+ * to disk during the commit operation. We also maintain a list of inodes
+ * that need to be committed during a fast commit in another in memory queue of
+ * inodes. During the commit operation, we commit in the following order:
+ *
+ * [1] Lock inodes for any further data updates by setting COMMITTING state
+ * [2] Submit data buffers of all the inodes
+ * [3] Wait for [2] to complete
+ * [4] Commit all the directory entry updates in the fast commit space
+ * [5] Commit all the changed inode structures
+ * [6] Write tail tag (this tag ensures the atomicity, please read the following
+ *     section for more details).
+ * [7] Wait for [4], [5] and [6] to complete.
+ *
+ * All the inode updates must call ext4_fc_start_update() before starting an
+ * update. If such an ongoing update is present, fast commit waits for it to
+ * complete. The completion of such an update is marked by
+ * ext4_fc_stop_update().
+ *
+ * Fast Commit Ineligibility
+ * -------------------------
+ * Not all operations are supported by fast commits today (e.g extended
+ * attributes). Fast commit ineligiblity is marked by calling one of the
+ * two following functions:
+ *
+ * - ext4_fc_mark_ineligible(): This makes next fast commit operation to fall
+ *   back to full commit. This is useful in case of transient errors.
+ *
+ * - ext4_fc_start_ineligible() and ext4_fc_stop_ineligible() - This makes all
+ *   the fast commits happening between ext4_fc_start_ineligible() and
+ *   ext4_fc_stop_ineligible() and one fast commit after the call to
+ *   ext4_fc_stop_ineligible() to fall back to full commits. It is important to
+ *   make one more fast commit to fall back to full commit after stop call so
+ *   that it guaranteed that the fast commit ineligible operation contained
+ *   within ext4_fc_start_ineligible() and ext4_fc_stop_ineligible() is
+ *   followed by at least 1 full commit.
+ *
+ * Atomicity of commits
+ * --------------------
+ * In order to gaurantee atomicity during the commit operation, fast commit
+ * uses "EXT4_FC_TAG_TAIL" tag that marks a fast commit as complete. Tail
+ * tag contains CRC of the contents and TID of the transaction after which
+ * this fast commit should be applied. Recovery code replays fast commit
+ * logs only if there's at least 1 valid tail present. For every fast commit
+ * operation, there is 1 tail. This means, we may end up with multiple tails
+ * in the fast commit space. Here's an example:
+ *
+ * - Create a new file A and remove existing file B
+ * - fsync()
+ * - Append contents to file A
+ * - Truncate file A
+ * - fsync()
+ *
+ * The fast commit space at the end of above operations would look like this:
+ *      [HEAD] [CREAT A] [UNLINK B] [TAIL] [ADD_RANGE A] [DEL_RANGE A] [TAIL]
+ *             |<---  Fast Commit 1   --->|<---      Fast Commit 2     ---->|
+ *
+ * Replay code should thus check for all the valid tails in the FC area.
+ *
+ * TODOs
+ * -----
+ * 1) Make fast commit atomic updates more fine grained. Today, a fast commit
+ *    eligible update must be protected within ext4_fc_start_update() and
+ *    ext4_fc_stop_update(). These routines are called at much higher
+ *    routines. This can be made more fine grained by combining with
+ *    ext4_journal_start().
+ *
+ * 2) Same above for ext4_fc_start_ineligible() and ext4_fc_stop_ineligible()
+ *
+ * 3) Handle more ineligible cases.
+ */
+
+#include <trace/events/ext4.h>
+static struct kmem_cache *ext4_fc_dentry_cachep;
+
+static void ext4_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
+{
+	BUFFER_TRACE(bh, "");
+	if (uptodate) {
+		ext4_debug("%s: Block %lld up-to-date",
+			   __func__, bh->b_blocknr);
+		set_buffer_uptodate(bh);
+	} else {
+		ext4_debug("%s: Block %lld not up-to-date",
+			   __func__, bh->b_blocknr);
+		clear_buffer_uptodate(bh);
+	}
+
+	unlock_buffer(bh);
+}
+
+static inline void ext4_fc_reset_inode(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	ei->i_fc_lblk_start = 0;
+	ei->i_fc_lblk_len = 0;
+}
+
+void ext4_fc_init_inode(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	ext4_fc_reset_inode(inode);
+	ext4_clear_inode_state(inode, EXT4_STATE_FC_COMMITTING);
+	INIT_LIST_HEAD(&ei->i_fc_list);
+	init_waitqueue_head(&ei->i_fc_wait);
+	atomic_set(&ei->i_fc_updates, 0);
+	ei->i_fc_committed_subtid = 0;
+}
+
+/*
+ * Inform Ext4's fast about start of an inode update
+ *
+ * This function is called by the high level call VFS callbacks before
+ * performing any inode update. This function blocks if there's an ongoing
+ * fast commit on the inode in question.
+ */
+void ext4_fc_start_update(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	if (!test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+restart:
+	spin_lock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+	if (list_empty(&ei->i_fc_list))
+		goto out;
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING)) {
+		wait_queue_head_t *wq;
+#if (BITS_PER_LONG < 64)
+		DEFINE_WAIT_BIT(wait, &ei->i_state_flags,
+				EXT4_STATE_FC_COMMITTING);
+		wq = bit_waitqueue(&ei->i_state_flags,
+				   EXT4_STATE_FC_COMMITTING);
+#else
+		DEFINE_WAIT_BIT(wait, &ei->i_flags,
+				EXT4_STATE_FC_COMMITTING);
+		wq = bit_waitqueue(&ei->i_flags,
+				   EXT4_STATE_FC_COMMITTING);
+#endif
+		prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
+		spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+		schedule();
+		finish_wait(wq, &wait.wq_entry);
+		goto restart;
+	}
+out:
+	atomic_inc(&ei->i_fc_updates);
+	spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+}
+
+/*
+ * Stop inode update and wake up waiting fast commits if any.
+ */
+void ext4_fc_stop_update(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	if (!test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+	if (atomic_dec_and_test(&ei->i_fc_updates))
+		wake_up_all(&ei->i_fc_wait);
+}
+
+/*
+ * Remove inode from fast commit list. If the inode is being committed
+ * we wait until inode commit is done.
+ */
+void ext4_fc_del(struct inode *inode)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+
+	if (!test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+restart:
+	spin_lock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+	if (list_empty(&ei->i_fc_list)) {
+		spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+		return;
+	}
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING)) {
+		wait_queue_head_t *wq;
+#if (BITS_PER_LONG < 64)
+		DEFINE_WAIT_BIT(wait, &ei->i_state_flags,
+				EXT4_STATE_FC_COMMITTING);
+		wq = bit_waitqueue(&ei->i_state_flags,
+				   EXT4_STATE_FC_COMMITTING);
+#else
+		DEFINE_WAIT_BIT(wait, &ei->i_flags,
+				EXT4_STATE_FC_COMMITTING);
+		wq = bit_waitqueue(&ei->i_flags,
+				   EXT4_STATE_FC_COMMITTING);
+#endif
+		prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
+		spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+		schedule();
+		finish_wait(wq, &wait.wq_entry);
+		goto restart;
+	}
+	if (!list_empty(&ei->i_fc_list))
+		list_del_init(&ei->i_fc_list);
+	spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
+}
+
+/*
+ * Mark file system as fast commit ineligible. This means that next commit
+ * operation would result in a full jbd2 commit.
+ */
+void ext4_fc_mark_ineligible(struct super_block *sb, int reason)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!test_opt2(sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+	sbi->s_mount_state |= EXT4_FC_INELIGIBLE;
+	WARN_ON(reason >= EXT4_FC_REASON_MAX);
+	sbi->s_fc_stats.fc_ineligible_reason_count[reason]++;
+}
+
+/*
+ * Start a fast commit ineligible update. Any commits that happen while
+ * such an operation is in progress fall back to full commits.
+ */
+void ext4_fc_start_ineligible(struct super_block *sb, int reason)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	if (!test_opt2(sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+	WARN_ON(reason >= EXT4_FC_REASON_MAX);
+	sbi->s_fc_stats.fc_ineligible_reason_count[reason]++;
+	atomic_inc(&sbi->s_fc_ineligible_updates);
+}
+
+/*
+ * Stop a fast commit ineligible update. We set EXT4_FC_INELIGIBLE flag here
+ * to ensure that after stopping the ineligible update, at least one full
+ * commit takes place.
+ */
+void ext4_fc_stop_ineligible(struct super_block *sb)
+{
+	if (!test_opt2(sb, JOURNAL_FAST_COMMIT) ||
+	    (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))
+		return;
+
+	EXT4_SB(sb)->s_mount_state |= EXT4_FC_INELIGIBLE;
+	atomic_dec(&EXT4_SB(sb)->s_fc_ineligible_updates);
+}
+
+static inline int ext4_fc_is_ineligible(struct super_block *sb)
+{
+	return (EXT4_SB(sb)->s_mount_state & EXT4_FC_INELIGIBLE) ||
+		atomic_read(&EXT4_SB(sb)->s_fc_ineligible_updates);
+}
+
+/*
+ * Generic fast commit tracking function. If this is the first time this we are
+ * called after a full commit, we initialize fast commit fields and then call
+ * __fc_track_fn() with update = 0. If we have already been called after a full
+ * commit, we pass update = 1. Based on that, the track function can determine
+ * if it needs to track a field for the first time or if it needs to just
+ * update the previously tracked value.
+ *
+ * If enqueue is set, this function enqueues the inode in fast commit list.
+ */
+static int ext4_fc_track_template(
+	struct inode *inode, int (*__fc_track_fn)(struct inode *, void *, bool),
+	void *args, int enqueue)
+{
+	tid_t running_txn_tid;
+	bool update = false;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	int ret;
+
+	if (!test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT) ||
+	    (sbi->s_mount_state & EXT4_FC_REPLAY))
+		return -EOPNOTSUPP;
+
+	if (ext4_fc_is_ineligible(inode->i_sb))
+		return -EINVAL;
+
+	running_txn_tid = sbi->s_journal ?
+		sbi->s_journal->j_commit_sequence + 1 : 0;
+
+	mutex_lock(&ei->i_fc_lock);
+	if (running_txn_tid == ei->i_sync_tid) {
+		update = true;
+	} else {
+		ext4_fc_reset_inode(inode);
+		ei->i_sync_tid = running_txn_tid;
+	}
+	ret = __fc_track_fn(inode, args, update);
+	mutex_unlock(&ei->i_fc_lock);
+
+	if (!enqueue)
+		return ret;
+
+	spin_lock(&sbi->s_fc_lock);
+	if (list_empty(&EXT4_I(inode)->i_fc_list))
+		list_add_tail(&EXT4_I(inode)->i_fc_list,
+				(sbi->s_mount_state & EXT4_FC_COMMITTING) ?
+				&sbi->s_fc_q[FC_Q_STAGING] :
+				&sbi->s_fc_q[FC_Q_MAIN]);
+	spin_unlock(&sbi->s_fc_lock);
+
+	return ret;
+}
+
+struct __track_dentry_update_args {
+	struct dentry *dentry;
+	int op;
+};
+
+/* __track_fn for directory entry updates. Called with ei->i_fc_lock. */
+static int __track_dentry_update(struct inode *inode, void *arg, bool update)
+{
+	struct ext4_fc_dentry_update *node;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct __track_dentry_update_args *dentry_update =
+		(struct __track_dentry_update_args *)arg;
+	struct dentry *dentry = dentry_update->dentry;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+	mutex_unlock(&ei->i_fc_lock);
+	node = kmem_cache_alloc(ext4_fc_dentry_cachep, GFP_NOFS);
+	if (!node) {
+		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_MEM);
+		mutex_lock(&ei->i_fc_lock);
+		return -ENOMEM;
+	}
+
+	node->fcd_op = dentry_update->op;
+	node->fcd_parent = dentry->d_parent->d_inode->i_ino;
+	node->fcd_ino = inode->i_ino;
+	if (dentry->d_name.len > DNAME_INLINE_LEN) {
+		node->fcd_name.name = kmalloc(dentry->d_name.len, GFP_NOFS);
+		if (!node->fcd_name.name) {
+			kmem_cache_free(ext4_fc_dentry_cachep, node);
+			ext4_fc_mark_ineligible(inode->i_sb,
+				EXT4_FC_REASON_MEM);
+			mutex_lock(&ei->i_fc_lock);
+			return -ENOMEM;
+		}
+		memcpy((u8 *)node->fcd_name.name, dentry->d_name.name,
+			dentry->d_name.len);
+	} else {
+		memcpy(node->fcd_iname, dentry->d_name.name,
+			dentry->d_name.len);
+		node->fcd_name.name = node->fcd_iname;
+	}
+	node->fcd_name.len = dentry->d_name.len;
+
+	spin_lock(&sbi->s_fc_lock);
+	if (sbi->s_mount_state & EXT4_FC_COMMITTING)
+		list_add_tail(&node->fcd_list,
+				&sbi->s_fc_dentry_q[FC_Q_STAGING]);
+	else
+		list_add_tail(&node->fcd_list, &sbi->s_fc_dentry_q[FC_Q_MAIN]);
+	spin_unlock(&sbi->s_fc_lock);
+	mutex_lock(&ei->i_fc_lock);
+
+	return 0;
+}
+
+void ext4_fc_track_unlink(struct inode *inode, struct dentry *dentry)
+{
+	struct __track_dentry_update_args args;
+	int ret;
+
+	args.dentry = dentry;
+	args.op = EXT4_FC_TAG_UNLINK;
+
+	ret = ext4_fc_track_template(inode, __track_dentry_update,
+					(void *)&args, 0);
+	trace_ext4_fc_track_unlink(inode, dentry, ret);
+}
+
+void ext4_fc_track_link(struct inode *inode, struct dentry *dentry)
+{
+	struct __track_dentry_update_args args;
+	int ret;
+
+	args.dentry = dentry;
+	args.op = EXT4_FC_TAG_LINK;
+
+	ret = ext4_fc_track_template(inode, __track_dentry_update,
+					(void *)&args, 0);
+	trace_ext4_fc_track_link(inode, dentry, ret);
+}
+
+void ext4_fc_track_create(struct inode *inode, struct dentry *dentry)
+{
+	struct __track_dentry_update_args args;
+	int ret;
+
+	args.dentry = dentry;
+	args.op = EXT4_FC_TAG_CREAT;
+
+	ret = ext4_fc_track_template(inode, __track_dentry_update,
+					(void *)&args, 0);
+	trace_ext4_fc_track_create(inode, dentry, ret);
+}
+
+/* __track_fn for inode tracking */
+static int __track_inode(struct inode *inode, void *arg, bool update)
+{
+	if (update)
+		return -EEXIST;
+
+	EXT4_I(inode)->i_fc_lblk_len = 0;
+
+	return 0;
+}
+
+void ext4_fc_track_inode(struct inode *inode)
+{
+	int ret;
+
+	if (S_ISDIR(inode->i_mode))
+		return;
+
+	ret = ext4_fc_track_template(inode, __track_inode, NULL, 1);
+	trace_ext4_fc_track_inode(inode, ret);
+}
+
+struct __track_range_args {
+	ext4_lblk_t start, end;
+};
+
+/* __track_fn for tracking data updates */
+static int __track_range(struct inode *inode, void *arg, bool update)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	ext4_lblk_t oldstart;
+	struct __track_range_args *__arg =
+		(struct __track_range_args *)arg;
+
+	if (inode->i_ino < EXT4_FIRST_INO(inode->i_sb)) {
+		ext4_debug("Special inode %ld being modified\n", inode->i_ino);
+		return -ECANCELED;
+	}
+
+	oldstart = ei->i_fc_lblk_start;
+
+	if (update && ei->i_fc_lblk_len > 0) {
+		ei->i_fc_lblk_start = min(ei->i_fc_lblk_start, __arg->start);
+		ei->i_fc_lblk_len =
+			max(oldstart + ei->i_fc_lblk_len - 1, __arg->end) -
+				ei->i_fc_lblk_start + 1;
+	} else {
+		ei->i_fc_lblk_start = __arg->start;
+		ei->i_fc_lblk_len = __arg->end - __arg->start + 1;
+	}
+
+	return 0;
+}
+
+void ext4_fc_track_range(struct inode *inode, ext4_lblk_t start,
+			 ext4_lblk_t end)
+{
+	struct __track_range_args args;
+	int ret;
+
+	if (S_ISDIR(inode->i_mode))
+		return;
+
+	args.start = start;
+	args.end = end;
+
+	ret = ext4_fc_track_template(inode,  __track_range, &args, 1);
+
+	trace_ext4_fc_track_range(inode, start, end, ret);
+}
+
+static void ext4_fc_submit_bh(struct super_block *sb)
+{
+	int write_flags = REQ_SYNC;
+	struct buffer_head *bh = EXT4_SB(sb)->s_fc_bh;
+
+	if (test_opt(sb, BARRIER))
+		write_flags |= REQ_FUA | REQ_PREFLUSH;
+	lock_buffer(bh);
+	clear_buffer_dirty(bh);
+	set_buffer_uptodate(bh);
+	bh->b_end_io = ext4_end_buffer_io_sync;
+	submit_bh(REQ_OP_WRITE, write_flags, bh);
+	EXT4_SB(sb)->s_fc_bh = NULL;
+}
+
+/* Ext4 commit path routines */
+
+/* memzero and update CRC */
+static void *ext4_fc_memzero(struct super_block *sb, void *dst, int len,
+				u32 *crc)
+{
+	void *ret;
+
+	ret = memset(dst, 0, len);
+	if (crc)
+		*crc = ext4_chksum(EXT4_SB(sb), *crc, dst, len);
+	return ret;
+}
+
+/*
+ * Allocate len bytes on a fast commit buffer.
+ *
+ * During the commit time this function is used to manage fast commit
+ * block space. We don't split a fast commit log onto different
+ * blocks. So this function makes sure that if there's not enough space
+ * on the current block, the remaining space in the current block is
+ * marked as unused by adding EXT4_FC_TAG_PAD tag. In that case,
+ * new block is from jbd2 and CRC is updated to reflect the padding
+ * we added.
+ */
+static u8 *ext4_fc_reserve_space(struct super_block *sb, int len, u32 *crc)
+{
+	struct ext4_fc_tl *tl;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct buffer_head *bh;
+	int bsize = sbi->s_journal->j_blocksize;
+	int ret, off = sbi->s_fc_bytes % bsize;
+	int pad_len;
+
+	/*
+	 * After allocating len, we should have space at least for a 0 byte
+	 * padding.
+	 */
+	if (len + sizeof(struct ext4_fc_tl) > bsize)
+		return NULL;
+
+	if (bsize - off - 1 > len + sizeof(struct ext4_fc_tl)) {
+		/*
+		 * Only allocate from current buffer if we have enough space for
+		 * this request AND we have space to add a zero byte padding.
+		 */
+		if (!sbi->s_fc_bh) {
+			ret = jbd2_fc_get_buf(EXT4_SB(sb)->s_journal, &bh);
+			if (ret)
+				return NULL;
+			sbi->s_fc_bh = bh;
+		}
+		sbi->s_fc_bytes += len;
+		return sbi->s_fc_bh->b_data + off;
+	}
+	/* Need to add PAD tag */
+	tl = (struct ext4_fc_tl *)(sbi->s_fc_bh->b_data + off);
+	tl->fc_tag = cpu_to_le16(EXT4_FC_TAG_PAD);
+	pad_len = bsize - off - 1 - sizeof(struct ext4_fc_tl);
+	tl->fc_len = cpu_to_le16(pad_len);
+	if (crc)
+		*crc = ext4_chksum(sbi, *crc, tl, sizeof(*tl));
+	if (pad_len > 0)
+		ext4_fc_memzero(sb, tl + 1, pad_len, crc);
+	ext4_fc_submit_bh(sb);
+
+	ret = jbd2_fc_get_buf(EXT4_SB(sb)->s_journal, &bh);
+	if (ret)
+		return NULL;
+	sbi->s_fc_bh = bh;
+	sbi->s_fc_bytes = (sbi->s_fc_bytes / bsize + 1) * bsize + len;
+	return sbi->s_fc_bh->b_data;
+}
+
+/* memcpy to fc reserved space and update CRC */
+static void *ext4_fc_memcpy(struct super_block *sb, void *dst, const void *src,
+				int len, u32 *crc)
+{
+	if (crc)
+		*crc = ext4_chksum(EXT4_SB(sb), *crc, src, len);
+	return memcpy(dst, src, len);
+}
+
+/*
+ * Complete a fast commit by writing tail tag.
+ *
+ * Writing tail tag marks the end of a fast commit. In order to guarantee
+ * atomicity, after writing tail tag, even if there's space remaining
+ * in the block, next commit shouldn't use it. That's why tail tag
+ * has the length as that of the remaining space on the block.
+ */
+static int ext4_fc_write_tail(struct super_block *sb, u32 crc)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_fc_tl tl;
+	struct ext4_fc_tail tail;
+	int off, bsize = sbi->s_journal->j_blocksize;
+	u8 *dst;
+
+	/*
+	 * ext4_fc_reserve_space takes care of allocating an extra block if
+	 * there's no enough space on this block for accommodating this tail.
+	 */
+	dst = ext4_fc_reserve_space(sb, sizeof(tl) + sizeof(tail), &crc);
+	if (!dst)
+		return -ENOSPC;
+
+	off = sbi->s_fc_bytes % bsize;
+
+	tl.fc_tag = cpu_to_le16(EXT4_FC_TAG_TAIL);
+	tl.fc_len = cpu_to_le16(bsize - off - 1 + sizeof(struct ext4_fc_tail));
+	sbi->s_fc_bytes = round_up(sbi->s_fc_bytes, bsize);
+
+	ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), &crc);
+	dst += sizeof(tl);
+	tail.fc_tid = cpu_to_le32(sbi->s_journal->j_running_transaction->t_tid);
+	ext4_fc_memcpy(sb, dst, &tail.fc_tid, sizeof(tail.fc_tid), &crc);
+	dst += sizeof(tail.fc_tid);
+	tail.fc_crc = cpu_to_le32(crc);
+	ext4_fc_memcpy(sb, dst, &tail.fc_crc, sizeof(tail.fc_crc), NULL);
+
+	ext4_fc_submit_bh(sb);
+
+	return 0;
+}
+
+/*
+ * Adds tag, length, value and updates CRC. Returns true if tlv was added.
+ * Returns false if there's not enough space.
+ */
+static bool ext4_fc_add_tlv(struct super_block *sb, u16 tag, u16 len, u8 *val,
+			   u32 *crc)
+{
+	struct ext4_fc_tl tl;
+	u8 *dst;
+
+	dst = ext4_fc_reserve_space(sb, sizeof(tl) + len, crc);
+	if (!dst)
+		return false;
+
+	tl.fc_tag = cpu_to_le16(tag);
+	tl.fc_len = cpu_to_le16(len);
+
+	ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), crc);
+	ext4_fc_memcpy(sb, dst + sizeof(tl), val, len, crc);
+
+	return true;
+}
+
+/* Same as above, but adds dentry tlv. */
+static  bool ext4_fc_add_dentry_tlv(struct super_block *sb, u16 tag,
+					int parent_ino, int ino, int dlen,
+					const unsigned char *dname,
+					u32 *crc)
+{
+	struct ext4_fc_dentry_info fcd;
+	struct ext4_fc_tl tl;
+	u8 *dst = ext4_fc_reserve_space(sb, sizeof(tl) + sizeof(fcd) + dlen,
+					crc);
+
+	if (!dst)
+		return false;
+
+	fcd.fc_parent_ino = cpu_to_le32(parent_ino);
+	fcd.fc_ino = cpu_to_le32(ino);
+	tl.fc_tag = cpu_to_le16(tag);
+	tl.fc_len = cpu_to_le16(sizeof(fcd) + dlen);
+	ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), crc);
+	dst += sizeof(tl);
+	ext4_fc_memcpy(sb, dst, &fcd, sizeof(fcd), crc);
+	dst += sizeof(fcd);
+	ext4_fc_memcpy(sb, dst, dname, dlen, crc);
+	dst += dlen;
+
+	return true;
+}
+
+/*
+ * Writes inode in the fast commit space under TLV with tag @tag.
+ * Returns 0 on success, error on failure.
+ */
+static int ext4_fc_write_inode(struct inode *inode, u32 *crc)
+{
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	int inode_len = EXT4_GOOD_OLD_INODE_SIZE;
+	int ret;
+	struct ext4_iloc iloc;
+	struct ext4_fc_inode fc_inode;
+	struct ext4_fc_tl tl;
+	u8 *dst;
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret)
+		return ret;
+
+	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE)
+		inode_len += ei->i_extra_isize;
+
+	fc_inode.fc_ino = cpu_to_le32(inode->i_ino);
+	tl.fc_tag = cpu_to_le16(EXT4_FC_TAG_INODE);
+	tl.fc_len = cpu_to_le16(inode_len + sizeof(fc_inode.fc_ino));
+
+	dst = ext4_fc_reserve_space(inode->i_sb,
+			sizeof(tl) + inode_len + sizeof(fc_inode.fc_ino), crc);
+	if (!dst)
+		return -ECANCELED;
+
+	if (!ext4_fc_memcpy(inode->i_sb, dst, &tl, sizeof(tl), crc))
+		return -ECANCELED;
+	dst += sizeof(tl);
+	if (!ext4_fc_memcpy(inode->i_sb, dst, &fc_inode, sizeof(fc_inode), crc))
+		return -ECANCELED;
+	dst += sizeof(fc_inode);
+	if (!ext4_fc_memcpy(inode->i_sb, dst, (u8 *)ext4_raw_inode(&iloc),
+					inode_len, crc))
+		return -ECANCELED;
+
+	return 0;
+}
+
+/*
+ * Writes updated data ranges for the inode in question. Updates CRC.
+ * Returns 0 on success, error otherwise.
+ */
+static int ext4_fc_write_inode_data(struct inode *inode, u32 *crc)
+{
+	ext4_lblk_t old_blk_size, cur_lblk_off, new_blk_size;
+	struct ext4_inode_info *ei = EXT4_I(inode);
+	struct ext4_map_blocks map;
+	struct ext4_fc_add_range fc_ext;
+	struct ext4_fc_del_range lrange;
+	struct ext4_extent *ex;
+	int ret;
+
+	mutex_lock(&ei->i_fc_lock);
+	if (ei->i_fc_lblk_len == 0) {
+		mutex_unlock(&ei->i_fc_lock);
+		return 0;
+	}
+	old_blk_size = ei->i_fc_lblk_start;
+	new_blk_size = ei->i_fc_lblk_start + ei->i_fc_lblk_len - 1;
+	ei->i_fc_lblk_len = 0;
+	mutex_unlock(&ei->i_fc_lock);
+
+	cur_lblk_off = old_blk_size;
+	jbd_debug(1, "%s: will try writing %d to %d for inode %ld\n",
+		  __func__, cur_lblk_off, new_blk_size, inode->i_ino);
+
+	while (cur_lblk_off <= new_blk_size) {
+		map.m_lblk = cur_lblk_off;
+		map.m_len = new_blk_size - cur_lblk_off + 1;
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+		if (ret < 0)
+			return -ECANCELED;
+
+		if (map.m_len == 0) {
+			cur_lblk_off++;
+			continue;
+		}
+
+		if (ret == 0) {
+			lrange.fc_ino = cpu_to_le32(inode->i_ino);
+			lrange.fc_lblk = cpu_to_le32(map.m_lblk);
+			lrange.fc_len = cpu_to_le32(map.m_len);
+			if (!ext4_fc_add_tlv(inode->i_sb, EXT4_FC_TAG_DEL_RANGE,
+					    sizeof(lrange), (u8 *)&lrange, crc))
+				return -ENOSPC;
+		} else {
+			fc_ext.fc_ino = cpu_to_le32(inode->i_ino);
+			ex = (struct ext4_extent *)&fc_ext.fc_ex;
+			ex->ee_block = cpu_to_le32(map.m_lblk);
+			ex->ee_len = cpu_to_le16(map.m_len);
+			ext4_ext_store_pblock(ex, map.m_pblk);
+			if (map.m_flags & EXT4_MAP_UNWRITTEN)
+				ext4_ext_mark_unwritten(ex);
+			else
+				ext4_ext_mark_initialized(ex);
+			if (!ext4_fc_add_tlv(inode->i_sb, EXT4_FC_TAG_ADD_RANGE,
+					    sizeof(fc_ext), (u8 *)&fc_ext, crc))
+				return -ENOSPC;
+		}
+
+		cur_lblk_off += map.m_len;
+	}
+
+	return 0;
+}
+
+
+/* Submit data for all the fast commit inodes */
+static int ext4_fc_submit_inode_data_all(journal_t *journal)
+{
+	struct super_block *sb = (struct super_block *)(journal->j_private);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_inode_info *ei;
+	struct list_head *pos;
+	int ret = 0;
+
+	spin_lock(&sbi->s_fc_lock);
+	sbi->s_mount_state |= EXT4_FC_COMMITTING;
+	list_for_each(pos, &sbi->s_fc_q[FC_Q_MAIN]) {
+		ei = list_entry(pos, struct ext4_inode_info, i_fc_list);
+		ext4_set_inode_state(&ei->vfs_inode, EXT4_STATE_FC_COMMITTING);
+		while (atomic_read(&ei->i_fc_updates)) {
+			DEFINE_WAIT(wait);
+
+			prepare_to_wait(&ei->i_fc_wait, &wait,
+						TASK_UNINTERRUPTIBLE);
+			if (atomic_read(&ei->i_fc_updates)) {
+				spin_unlock(&sbi->s_fc_lock);
+				schedule();
+				spin_lock(&sbi->s_fc_lock);
+			}
+			finish_wait(&ei->i_fc_wait, &wait);
+		}
+		spin_unlock(&sbi->s_fc_lock);
+		ret = jbd2_submit_inode_data(ei->jinode);
+		if (ret)
+			return ret;
+		spin_lock(&sbi->s_fc_lock);
+	}
+	spin_unlock(&sbi->s_fc_lock);
+
+	return ret;
+}
+
+/* Wait for completion of data for all the fast commit inodes */
+static int ext4_fc_wait_inode_data_all(journal_t *journal)
+{
+	struct super_block *sb = (struct super_block *)(journal->j_private);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_inode_info *pos, *n;
+	int ret = 0;
+
+	spin_lock(&sbi->s_fc_lock);
+	list_for_each_entry_safe(pos, n, &sbi->s_fc_q[FC_Q_MAIN], i_fc_list) {
+		if (!ext4_test_inode_state(&pos->vfs_inode,
+					   EXT4_STATE_FC_COMMITTING))
+			continue;
+		spin_unlock(&sbi->s_fc_lock);
+
+		ret = jbd2_wait_inode_data(journal, pos->jinode);
+		if (ret)
+			return ret;
+		spin_lock(&sbi->s_fc_lock);
+	}
+	spin_unlock(&sbi->s_fc_lock);
+
+	return 0;
+}
+
+/* Commit all the directory entry updates */
+static int ext4_fc_commit_dentry_updates(journal_t *journal, u32 *crc)
+{
+	struct super_block *sb = (struct super_block *)(journal->j_private);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_fc_dentry_update *fc_dentry;
+	struct inode *inode;
+	struct list_head *pos, *n, *fcd_pos, *fcd_n;
+	struct ext4_inode_info *ei;
+	int ret;
+
+	if (list_empty(&sbi->s_fc_dentry_q[FC_Q_MAIN]))
+		return 0;
+	list_for_each_safe(fcd_pos, fcd_n, &sbi->s_fc_dentry_q[FC_Q_MAIN]) {
+		fc_dentry = list_entry(fcd_pos, struct ext4_fc_dentry_update,
+					fcd_list);
+		if (fc_dentry->fcd_op != EXT4_FC_TAG_CREAT) {
+			spin_unlock(&sbi->s_fc_lock);
+			if (!ext4_fc_add_dentry_tlv(
+				sb, fc_dentry->fcd_op,
+				fc_dentry->fcd_parent, fc_dentry->fcd_ino,
+				fc_dentry->fcd_name.len,
+				fc_dentry->fcd_name.name, crc)) {
+				ret = -ENOSPC;
+				goto lock_and_exit;
+			}
+			spin_lock(&sbi->s_fc_lock);
+			continue;
+		}
+
+		inode = NULL;
+		list_for_each_safe(pos, n, &sbi->s_fc_q[FC_Q_MAIN]) {
+			ei = list_entry(pos, struct ext4_inode_info, i_fc_list);
+			if (ei->vfs_inode.i_ino == fc_dentry->fcd_ino) {
+				inode = &ei->vfs_inode;
+				break;
+			}
+		}
+		/*
+		 * If we don't find inode in our list, then it was deleted,
+		 * in which case, we don't need to record it's create tag.
+		 */
+		if (!inode)
+			continue;
+		spin_unlock(&sbi->s_fc_lock);
+
+		/*
+		 * We first write the inode and then the create dirent. This
+		 * allows the recovery code to create an unnamed inode first
+		 * and then link it to a directory entry. This allows us
+		 * to use namei.c routines almost as is and simplifies
+		 * the recovery code.
+		 */
+		ret = ext4_fc_write_inode(inode, crc);
+		if (ret)
+			goto lock_and_exit;
+
+		ret = ext4_fc_write_inode_data(inode, crc);
+		if (ret)
+			goto lock_and_exit;
+
+		if (!ext4_fc_add_dentry_tlv(
+			sb, fc_dentry->fcd_op,
+			fc_dentry->fcd_parent, fc_dentry->fcd_ino,
+			fc_dentry->fcd_name.len,
+			fc_dentry->fcd_name.name, crc)) {
+			spin_lock(&sbi->s_fc_lock);
+			ret = -ENOSPC;
+			goto lock_and_exit;
+		}
+
+		spin_lock(&sbi->s_fc_lock);
+	}
+	return 0;
+lock_and_exit:
+	spin_lock(&sbi->s_fc_lock);
+	return ret;
+}
+
+static int ext4_fc_perform_commit(journal_t *journal)
+{
+	struct super_block *sb = (struct super_block *)(journal->j_private);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_inode_info *iter;
+	struct ext4_fc_head head;
+	struct list_head *pos;
+	struct inode *inode;
+	struct blk_plug plug;
+	int ret = 0;
+	u32 crc = 0;
+
+	ret = ext4_fc_submit_inode_data_all(journal);
+	if (ret)
+		return ret;
+
+	ret = ext4_fc_wait_inode_data_all(journal);
+	if (ret)
+		return ret;
+
+	blk_start_plug(&plug);
+	if (sbi->s_fc_bytes == 0) {
+		/*
+		 * Add a head tag only if this is the first fast commit
+		 * in this TID.
+		 */
+		head.fc_features = cpu_to_le32(EXT4_FC_SUPPORTED_FEATURES);
+		head.fc_tid = cpu_to_le32(
+			sbi->s_journal->j_running_transaction->t_tid);
+		if (!ext4_fc_add_tlv(sb, EXT4_FC_TAG_HEAD, sizeof(head),
+			(u8 *)&head, &crc))
+			goto out;
+	}
+
+	spin_lock(&sbi->s_fc_lock);
+	ret = ext4_fc_commit_dentry_updates(journal, &crc);
+	if (ret) {
+		spin_unlock(&sbi->s_fc_lock);
+		goto out;
+	}
+
+	list_for_each(pos, &sbi->s_fc_q[FC_Q_MAIN]) {
+		iter = list_entry(pos, struct ext4_inode_info, i_fc_list);
+		inode = &iter->vfs_inode;
+		if (!ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING))
+			continue;
+
+		spin_unlock(&sbi->s_fc_lock);
+		ret = ext4_fc_write_inode_data(inode, &crc);
+		if (ret)
+			goto out;
+		ret = ext4_fc_write_inode(inode, &crc);
+		if (ret)
+			goto out;
+		spin_lock(&sbi->s_fc_lock);
+		EXT4_I(inode)->i_fc_committed_subtid =
+			atomic_read(&sbi->s_fc_subtid);
+	}
+	spin_unlock(&sbi->s_fc_lock);
+
+	ret = ext4_fc_write_tail(sb, crc);
+
+out:
+	blk_finish_plug(&plug);
+	return ret;
+}
+
+/*
+ * The main commit entry point. Performs a fast commit for transaction
+ * commit_tid if needed. If it's not possible to perform a fast commit
+ * due to various reasons, we fall back to full commit. Returns 0
+ * on success, error otherwise.
+ */
+int ext4_fc_commit(journal_t *journal, tid_t commit_tid)
+{
+	struct super_block *sb = (struct super_block *)(journal->j_private);
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	int nblks = 0, ret, bsize = journal->j_blocksize;
+	int subtid = atomic_read(&sbi->s_fc_subtid);
+	int reason = EXT4_FC_REASON_OK, fc_bufs_before = 0;
+	ktime_t start_time, commit_time;
+
+	trace_ext4_fc_commit_start(sb);
+
+	start_time = ktime_get();
+
+	if (!test_opt2(sb, JOURNAL_FAST_COMMIT) ||
+		(ext4_fc_is_ineligible(sb))) {
+		reason = EXT4_FC_REASON_INELIGIBLE;
+		goto out;
+	}
+
+restart_fc:
+	ret = jbd2_fc_begin_commit(journal, commit_tid);
+	if (ret == -EALREADY) {
+		/* There was an ongoing commit, check if we need to restart */
+		if (atomic_read(&sbi->s_fc_subtid) <= subtid &&
+			commit_tid > journal->j_commit_sequence)
+			goto restart_fc;
+		reason = EXT4_FC_REASON_ALREADY_COMMITTED;
+		goto out;
+	} else if (ret) {
+		sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
+		reason = EXT4_FC_REASON_FC_START_FAILED;
+		goto out;
+	}
+
+	fc_bufs_before = (sbi->s_fc_bytes + bsize - 1) / bsize;
+	ret = ext4_fc_perform_commit(journal);
+	if (ret < 0) {
+		sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
+		reason = EXT4_FC_REASON_FC_FAILED;
+		goto out;
+	}
+	nblks = (sbi->s_fc_bytes + bsize - 1) / bsize - fc_bufs_before;
+	ret = jbd2_fc_wait_bufs(journal, nblks);
+	if (ret < 0) {
+		sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
+		reason = EXT4_FC_REASON_FC_FAILED;
+		goto out;
+	}
+	atomic_inc(&sbi->s_fc_subtid);
+	jbd2_fc_end_commit(journal);
+out:
+	/* Has any ineligible update happened since we started? */
+	if (reason == EXT4_FC_REASON_OK && ext4_fc_is_ineligible(sb)) {
+		sbi->s_fc_stats.fc_ineligible_reason_count[EXT4_FC_COMMIT_FAILED]++;
+		reason = EXT4_FC_REASON_INELIGIBLE;
+	}
+
+	spin_lock(&sbi->s_fc_lock);
+	if (reason != EXT4_FC_REASON_OK &&
+		reason != EXT4_FC_REASON_ALREADY_COMMITTED) {
+		sbi->s_fc_stats.fc_ineligible_commits++;
+	} else {
+		sbi->s_fc_stats.fc_num_commits++;
+		sbi->s_fc_stats.fc_numblks += nblks;
+	}
+	spin_unlock(&sbi->s_fc_lock);
+	nblks = (reason == EXT4_FC_REASON_OK) ? nblks : 0;
+	trace_ext4_fc_commit_stop(sb, nblks, reason);
+	commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
+	/*
+	 * weight the commit time higher than the average time so we don't
+	 * react too strongly to vast changes in the commit time
+	 */
+	if (likely(sbi->s_fc_avg_commit_time))
+		sbi->s_fc_avg_commit_time = (commit_time +
+				sbi->s_fc_avg_commit_time * 3) / 4;
+	else
+		sbi->s_fc_avg_commit_time = commit_time;
+	jbd_debug(1,
+		"Fast commit ended with blks = %d, reason = %d, subtid - %d",
+		nblks, reason, subtid);
+	if (reason == EXT4_FC_REASON_FC_FAILED)
+		return jbd2_fc_end_commit_fallback(journal, commit_tid);
+	if (reason == EXT4_FC_REASON_FC_START_FAILED ||
+		reason == EXT4_FC_REASON_INELIGIBLE)
+		return jbd2_complete_transaction(journal, commit_tid);
+	return 0;
+}
+
+/*
+ * Fast commit cleanup routine. This is called after every fast commit and
+ * full commit. full is true if we are called after a full commit.
+ */
+static void ext4_fc_cleanup(journal_t *journal, int full)
+{
+	struct super_block *sb = journal->j_private;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_inode_info *iter;
+	struct ext4_fc_dentry_update *fc_dentry;
+	struct list_head *pos, *n;
+
+	if (full && sbi->s_fc_bh)
+		sbi->s_fc_bh = NULL;
+
+	jbd2_fc_release_bufs(journal);
+
+	spin_lock(&sbi->s_fc_lock);
+	list_for_each_safe(pos, n, &sbi->s_fc_q[FC_Q_MAIN]) {
+		iter = list_entry(pos, struct ext4_inode_info, i_fc_list);
+		list_del_init(&iter->i_fc_list);
+		ext4_clear_inode_state(&iter->vfs_inode,
+				       EXT4_STATE_FC_COMMITTING);
+		ext4_fc_reset_inode(&iter->vfs_inode);
+		/* Make sure EXT4_STATE_FC_COMMITTING bit is clear */
+		smp_mb();
+#if (BITS_PER_LONG < 64)
+		wake_up_bit(&iter->i_state_flags, EXT4_STATE_FC_COMMITTING);
+#else
+		wake_up_bit(&iter->i_flags, EXT4_STATE_FC_COMMITTING);
+#endif
+	}
+
+	while (!list_empty(&sbi->s_fc_dentry_q[FC_Q_MAIN])) {
+		fc_dentry = list_first_entry(&sbi->s_fc_dentry_q[FC_Q_MAIN],
+					     struct ext4_fc_dentry_update,
+					     fcd_list);
+		list_del_init(&fc_dentry->fcd_list);
+		spin_unlock(&sbi->s_fc_lock);
+
+		if (fc_dentry->fcd_name.name &&
+			fc_dentry->fcd_name.len > DNAME_INLINE_LEN)
+			kfree(fc_dentry->fcd_name.name);
+		kmem_cache_free(ext4_fc_dentry_cachep, fc_dentry);
+		spin_lock(&sbi->s_fc_lock);
+	}
+
+	list_splice_init(&sbi->s_fc_dentry_q[FC_Q_STAGING],
+				&sbi->s_fc_dentry_q[FC_Q_MAIN]);
+	list_splice_init(&sbi->s_fc_q[FC_Q_STAGING],
+				&sbi->s_fc_q[FC_Q_STAGING]);
+
+	sbi->s_mount_state &= ~EXT4_FC_COMMITTING;
+	sbi->s_mount_state &= ~EXT4_FC_INELIGIBLE;
+
+	if (full)
+		sbi->s_fc_bytes = 0;
+	spin_unlock(&sbi->s_fc_lock);
+	trace_ext4_fc_stats(sb);
+}
+
+/* Ext4 Replay Path Routines */
+
+/* Get length of a particular tlv */
+static inline int ext4_fc_tag_len(struct ext4_fc_tl *tl)
+{
+	return le16_to_cpu(tl->fc_len);
+}
+
+/* Get a pointer to "value" of a tlv */
+static inline u8 *ext4_fc_tag_val(struct ext4_fc_tl *tl)
+{
+	return (u8 *)tl + sizeof(*tl);
+}
+
+/* Helper struct for dentry replay routines */
+struct dentry_info_args {
+	int parent_ino, dname_len, ino, inode_len;
+	char *dname;
+};
+
+static inline void tl_to_darg(struct dentry_info_args *darg,
+				struct  ext4_fc_tl *tl)
+{
+	struct ext4_fc_dentry_info *fcd;
+
+	fcd = (struct ext4_fc_dentry_info *)ext4_fc_tag_val(tl);
+
+	darg->parent_ino = le32_to_cpu(fcd->fc_parent_ino);
+	darg->ino = le32_to_cpu(fcd->fc_ino);
+	darg->dname = fcd->fc_dname;
+	darg->dname_len = ext4_fc_tag_len(tl) -
+			sizeof(struct ext4_fc_dentry_info);
+}
+
+/* Unlink replay function */
+static int ext4_fc_replay_unlink(struct super_block *sb, struct ext4_fc_tl *tl)
+{
+	struct inode *inode, *old_parent;
+	struct qstr entry;
+	struct dentry_info_args darg;
+	int ret = 0;
+
+	tl_to_darg(&darg, tl);
+
+	trace_ext4_fc_replay(sb, EXT4_FC_TAG_UNLINK, darg.ino,
+			darg.parent_ino, darg.dname_len);
+
+	entry.name = darg.dname;
+	entry.len = darg.dname_len;
+	inode = ext4_iget(sb, darg.ino, EXT4_IGET_NORMAL);
+
+	if (IS_ERR_OR_NULL(inode)) {
+		jbd_debug(1, "Inode %d not found", darg.ino);
+		return 0;
+	}
+
+	old_parent = ext4_iget(sb, darg.parent_ino,
+				EXT4_IGET_NORMAL);
+	if (IS_ERR_OR_NULL(old_parent)) {
+		jbd_debug(1, "Dir with inode  %d not found", darg.parent_ino);
+		iput(inode);
+		return 0;
+	}
+
+	ret = __ext4_unlink(old_parent, &entry, inode);
+	/* -ENOENT ok coz it might not exist anymore. */
+	if (ret == -ENOENT)
+		ret = 0;
+	iput(old_parent);
+	iput(inode);
+	return ret;
+}
+
+static int ext4_fc_replay_link_internal(struct super_block *sb,
+				struct dentry_info_args *darg,
+				struct inode *inode)
+{
+	struct inode *dir = NULL;
+	struct dentry *dentry_dir = NULL, *dentry_inode = NULL;
+	struct qstr qstr_dname = QSTR_INIT(darg->dname, darg->dname_len);
+	int ret = 0;
+
+	dir = ext4_iget(sb, darg->parent_ino, EXT4_IGET_NORMAL);
+	if (IS_ERR(dir)) {
+		jbd_debug(1, "Dir with inode %d not found.", darg->parent_ino);
+		dir = NULL;
+		goto out;
+	}
+
+	dentry_dir = d_obtain_alias(dir);
+	if (IS_ERR(dentry_dir)) {
+		jbd_debug(1, "Failed to obtain dentry");
+		dentry_dir = NULL;
+		goto out;
+	}
+
+	dentry_inode = d_alloc(dentry_dir, &qstr_dname);
+	if (!dentry_inode) {
+		jbd_debug(1, "Inode dentry not created.");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = __ext4_link(dir, inode, dentry_inode);
+	/*
+	 * It's possible that link already existed since data blocks
+	 * for the dir in question got persisted before we crashed OR
+	 * we replayed this tag and crashed before the entire replay
+	 * could complete.
+	 */
+	if (ret && ret != -EEXIST) {
+		jbd_debug(1, "Failed to link\n");
+		goto out;
+	}
+
+	ret = 0;
+out:
+	if (dentry_dir) {
+		d_drop(dentry_dir);
+		dput(dentry_dir);
+	} else if (dir) {
+		iput(dir);
+	}
+	if (dentry_inode) {
+		d_drop(dentry_inode);
+		dput(dentry_inode);
+	}
+
+	return ret;
+}
+
+/* Link replay function */
+static int ext4_fc_replay_link(struct super_block *sb, struct ext4_fc_tl *tl)
+{
+	struct inode *inode;
+	struct dentry_info_args darg;
+	int ret = 0;
+
+	tl_to_darg(&darg, tl);
+	trace_ext4_fc_replay(sb, EXT4_FC_TAG_LINK, darg.ino,
+			darg.parent_ino, darg.dname_len);
+
+	inode = ext4_iget(sb, darg.ino, EXT4_IGET_NORMAL);
+	if (IS_ERR_OR_NULL(inode)) {
+		jbd_debug(1, "Inode not found.");
+		return 0;
+	}
+
+	ret = ext4_fc_replay_link_internal(sb, &darg, inode);
+	iput(inode);
+	return ret;
+}
+
+/*
+ * Record all the modified inodes during replay. We use this later to setup
+ * block bitmaps correctly.
+ */
+static int ext4_fc_record_modified_inode(struct super_block *sb, int ino)
+{
+	struct ext4_fc_replay_state *state;
+	int i;
+
+	state = &EXT4_SB(sb)->s_fc_replay_state;
+	for (i = 0; i < state->fc_modified_inodes_used; i++)
+		if (state->fc_modified_inodes[i] == ino)
+			return 0;
+	if (state->fc_modified_inodes_used == state->fc_modified_inodes_size) {
+		state->fc_modified_inodes_size +=
+			EXT4_FC_REPLAY_REALLOC_INCREMENT;
+		state->fc_modified_inodes = krealloc(
+					state->fc_modified_inodes, sizeof(int) *
+					state->fc_modified_inodes_size,
+					GFP_KERNEL);
+		if (!state->fc_modified_inodes)
+			return -ENOMEM;
+	}
+	state->fc_modified_inodes[state->fc_modified_inodes_used++] = ino;
+	return 0;
+}
+
+/*
+ * Inode replay function
+ */
+static int ext4_fc_replay_inode(struct super_block *sb, struct ext4_fc_tl *tl)
+{
+	struct ext4_fc_inode *fc_inode;
+	struct ext4_inode *raw_inode;
+	struct ext4_inode *raw_fc_inode;
+	struct inode *inode = NULL;
+	struct ext4_iloc iloc;
+	int inode_len, ino, ret, tag = le16_to_cpu(tl->fc_tag);
+	struct ext4_extent_header *eh;
+
+	fc_inode = (struct ext4_fc_inode *)ext4_fc_tag_val(tl);
+
+	ino = le32_to_cpu(fc_inode->fc_ino);
+	trace_ext4_fc_replay(sb, tag, ino, 0, 0);
+
+	inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
+	if (!IS_ERR_OR_NULL(inode)) {
+		ext4_ext_clear_bb(inode);
+		iput(inode);
+	}
+
+	ext4_fc_record_modified_inode(sb, ino);
+
+	raw_fc_inode = (struct ext4_inode *)fc_inode->fc_raw_inode;
+	ret = ext4_get_fc_inode_loc(sb, ino, &iloc);
+	if (ret)
+		goto out;
+
+	inode_len = ext4_fc_tag_len(tl) - sizeof(struct ext4_fc_inode);
+	raw_inode = ext4_raw_inode(&iloc);
+
+	memcpy(raw_inode, raw_fc_inode, offsetof(struct ext4_inode, i_block));
+	memcpy(&raw_inode->i_generation, &raw_fc_inode->i_generation,
+		inode_len - offsetof(struct ext4_inode, i_generation));
+	if (le32_to_cpu(raw_inode->i_flags) & EXT4_EXTENTS_FL) {
+		eh = (struct ext4_extent_header *)(&raw_inode->i_block[0]);
+		if (eh->eh_magic != EXT4_EXT_MAGIC) {
+			memset(eh, 0, sizeof(*eh));
+			eh->eh_magic = EXT4_EXT_MAGIC;
+			eh->eh_max = cpu_to_le16(
+				(sizeof(raw_inode->i_block) -
+				 sizeof(struct ext4_extent_header))
+				 / sizeof(struct ext4_extent));
+		}
+	} else if (le32_to_cpu(raw_inode->i_flags) & EXT4_INLINE_DATA_FL) {
+		memcpy(raw_inode->i_block, raw_fc_inode->i_block,
+			sizeof(raw_inode->i_block));
+	}
+
+	/* Immediately update the inode on disk. */
+	ret = ext4_handle_dirty_metadata(NULL, NULL, iloc.bh);
+	if (ret)
+		goto out;
+	ret = sync_dirty_buffer(iloc.bh);
+	if (ret)
+		goto out;
+	ret = ext4_mark_inode_used(sb, ino);
+	if (ret)
+		goto out;
+
+	/* Given that we just wrote the inode on disk, this SHOULD succeed. */
+	inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
+	if (IS_ERR_OR_NULL(inode)) {
+		jbd_debug(1, "Inode not found.");
+		return -EFSCORRUPTED;
+	}
+
+	/*
+	 * Our allocator could have made different decisions than before
+	 * crashing. This should be fixed but until then, we calculate
+	 * the number of blocks the inode.
+	 */
+	ext4_ext_replay_set_iblocks(inode);
+
+	inode->i_generation = le32_to_cpu(ext4_raw_inode(&iloc)->i_generation);
+	ext4_reset_inode_seed(inode);
+
+	ext4_inode_csum_set(inode, ext4_raw_inode(&iloc), EXT4_I(inode));
+	ret = ext4_handle_dirty_metadata(NULL, NULL, iloc.bh);
+	sync_dirty_buffer(iloc.bh);
+	brelse(iloc.bh);
+out:
+	iput(inode);
+	if (!ret)
+		blkdev_issue_flush(sb->s_bdev, GFP_KERNEL);
+
+	return 0;
+}
+
+/*
+ * Dentry create replay function.
+ *
+ * EXT4_FC_TAG_CREAT is preceded by EXT4_FC_TAG_INODE_FULL. Which means, the
+ * inode for which we are trying to create a dentry here, should already have
+ * been replayed before we start here.
+ */
+static int ext4_fc_replay_create(struct super_block *sb, struct ext4_fc_tl *tl)
+{
+	int ret = 0;
+	struct inode *inode = NULL;
+	struct inode *dir = NULL;
+	struct dentry_info_args darg;
+
+	tl_to_darg(&darg, tl);
+
+	trace_ext4_fc_replay(sb, EXT4_FC_TAG_CREAT, darg.ino,
+			darg.parent_ino, darg.dname_len);
+
+	/* This takes care of update group descriptor and other metadata */
+	ret = ext4_mark_inode_used(sb, darg.ino);
+	if (ret)
+		goto out;
+
+	inode = ext4_iget(sb, darg.ino, EXT4_IGET_NORMAL);
+	if (IS_ERR_OR_NULL(inode)) {
+		jbd_debug(1, "inode %d not found.", darg.ino);
+		inode = NULL;
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (S_ISDIR(inode->i_mode)) {
+		/*
+		 * If we are creating a directory, we need to make sure that the
+		 * dot and dot dot dirents are setup properly.
+		 */
+		dir = ext4_iget(sb, darg.parent_ino, EXT4_IGET_NORMAL);
+		if (IS_ERR_OR_NULL(dir)) {
+			jbd_debug(1, "Dir %d not found.", darg.ino);
+			goto out;
+		}
+		ret = ext4_init_new_dir(NULL, dir, inode);
+		iput(dir);
+		if (ret) {
+			ret = 0;
+			goto out;
+		}
+	}
+	ret = ext4_fc_replay_link_internal(sb, &darg, inode);
+	if (ret)
+		goto out;
+	set_nlink(inode, 1);
+	ext4_mark_inode_dirty(NULL, inode);
+out:
+	if (inode)
+		iput(inode);
+	return ret;
+}
+
+/*
+ * Record physical disk regions which are in use as per fast commit area. Our
+ * simple replay phase allocator excludes these regions from allocation.
+ */
+static int ext4_fc_record_regions(struct super_block *sb, int ino,
+		ext4_lblk_t lblk, ext4_fsblk_t pblk, int len)
+{
+	struct ext4_fc_replay_state *state;
+	struct ext4_fc_alloc_region *region;
+
+	state = &EXT4_SB(sb)->s_fc_replay_state;
+	if (state->fc_regions_used == state->fc_regions_size) {
+		state->fc_regions_size +=
+			EXT4_FC_REPLAY_REALLOC_INCREMENT;
+		state->fc_regions = krealloc(
+					state->fc_regions,
+					state->fc_regions_size *
+					sizeof(struct ext4_fc_alloc_region),
+					GFP_KERNEL);
+		if (!state->fc_regions)
+			return -ENOMEM;
+	}
+	region = &state->fc_regions[state->fc_regions_used++];
+	region->ino = ino;
+	region->lblk = lblk;
+	region->pblk = pblk;
+	region->len = len;
+
+	return 0;
+}
+
+/* Replay add range tag */
+static int ext4_fc_replay_add_range(struct super_block *sb,
+				struct ext4_fc_tl *tl)
+{
+	struct ext4_fc_add_range *fc_add_ex;
+	struct ext4_extent newex, *ex;
+	struct inode *inode;
+	ext4_lblk_t start, cur;
+	int remaining, len;
+	ext4_fsblk_t start_pblk;
+	struct ext4_map_blocks map;
+	struct ext4_ext_path *path = NULL;
+	int ret;
+
+	fc_add_ex = (struct ext4_fc_add_range *)ext4_fc_tag_val(tl);
+	ex = (struct ext4_extent *)&fc_add_ex->fc_ex;
+
+	trace_ext4_fc_replay(sb, EXT4_FC_TAG_ADD_RANGE,
+		le32_to_cpu(fc_add_ex->fc_ino), le32_to_cpu(ex->ee_block),
+		ext4_ext_get_actual_len(ex));
+
+	inode = ext4_iget(sb, le32_to_cpu(fc_add_ex->fc_ino),
+				EXT4_IGET_NORMAL);
+	if (IS_ERR_OR_NULL(inode)) {
+		jbd_debug(1, "Inode not found.");
+		return 0;
+	}
+
+	ret = ext4_fc_record_modified_inode(sb, inode->i_ino);
+
+	start = le32_to_cpu(ex->ee_block);
+	start_pblk = ext4_ext_pblock(ex);
+	len = ext4_ext_get_actual_len(ex);
+
+	cur = start;
+	remaining = len;
+	jbd_debug(1, "ADD_RANGE, lblk %d, pblk %lld, len %d, unwritten %d, inode %ld\n",
+		  start, start_pblk, len, ext4_ext_is_unwritten(ex),
+		  inode->i_ino);
+
+	while (remaining > 0) {
+		map.m_lblk = cur;
+		map.m_len = remaining;
+		map.m_pblk = 0;
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+
+		if (ret < 0) {
+			iput(inode);
+			return 0;
+		}
+
+		if (ret == 0) {
+			/* Range is not mapped */
+			path = ext4_find_extent(inode, cur, NULL, 0);
+			if (!path)
+				continue;
+			memset(&newex, 0, sizeof(newex));
+			newex.ee_block = cpu_to_le32(cur);
+			ext4_ext_store_pblock(
+				&newex, start_pblk + cur - start);
+			newex.ee_len = cpu_to_le16(map.m_len);
+			if (ext4_ext_is_unwritten(ex))
+				ext4_ext_mark_unwritten(&newex);
+			down_write(&EXT4_I(inode)->i_data_sem);
+			ret = ext4_ext_insert_extent(
+				NULL, inode, &path, &newex, 0);
+			up_write((&EXT4_I(inode)->i_data_sem));
+			ext4_ext_drop_refs(path);
+			kfree(path);
+			if (ret) {
+				iput(inode);
+				return 0;
+			}
+			goto next;
+		}
+
+		if (start_pblk + cur - start != map.m_pblk) {
+			/*
+			 * Logical to physical mapping changed. This can happen
+			 * if this range was removed and then reallocated to
+			 * map to new physical blocks during a fast commit.
+			 */
+			ret = ext4_ext_replay_update_ex(inode, cur, map.m_len,
+					ext4_ext_is_unwritten(ex),
+					start_pblk + cur - start);
+			if (ret) {
+				iput(inode);
+				return 0;
+			}
+			/*
+			 * Mark the old blocks as free since they aren't used
+			 * anymore. We maintain an array of all the modified
+			 * inodes. In case these blocks are still used at either
+			 * a different logical range in the same inode or in
+			 * some different inode, we will mark them as allocated
+			 * at the end of the FC replay using our array of
+			 * modified inodes.
+			 */
+			ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
+			goto next;
+		}
+
+		/* Range is mapped and needs a state change */
+		jbd_debug(1, "Converting from %d to %d %lld",
+				map.m_flags & EXT4_MAP_UNWRITTEN,
+			ext4_ext_is_unwritten(ex), map.m_pblk);
+		ret = ext4_ext_replay_update_ex(inode, cur, map.m_len,
+					ext4_ext_is_unwritten(ex), map.m_pblk);
+		if (ret) {
+			iput(inode);
+			return 0;
+		}
+		/*
+		 * We may have split the extent tree while toggling the state.
+		 * Try to shrink the extent tree now.
+		 */
+		ext4_ext_replay_shrink_inode(inode, start + len);
+next:
+		cur += map.m_len;
+		remaining -= map.m_len;
+	}
+	ext4_ext_replay_shrink_inode(inode, i_size_read(inode) >>
+					sb->s_blocksize_bits);
+	iput(inode);
+	return 0;
+}
+
+/* Replay DEL_RANGE tag */
+static int
+ext4_fc_replay_del_range(struct super_block *sb, struct ext4_fc_tl *tl)
+{
+	struct inode *inode;
+	struct ext4_fc_del_range *lrange;
+	struct ext4_map_blocks map;
+	ext4_lblk_t cur, remaining;
+	int ret;
+
+	lrange = (struct ext4_fc_del_range *)ext4_fc_tag_val(tl);
+	cur = le32_to_cpu(lrange->fc_lblk);
+	remaining = le32_to_cpu(lrange->fc_len);
+
+	trace_ext4_fc_replay(sb, EXT4_FC_TAG_DEL_RANGE,
+		le32_to_cpu(lrange->fc_ino), cur, remaining);
+
+	inode = ext4_iget(sb, le32_to_cpu(lrange->fc_ino), EXT4_IGET_NORMAL);
+	if (IS_ERR_OR_NULL(inode)) {
+		jbd_debug(1, "Inode %d not found", le32_to_cpu(lrange->fc_ino));
+		return 0;
+	}
+
+	ret = ext4_fc_record_modified_inode(sb, inode->i_ino);
+
+	jbd_debug(1, "DEL_RANGE, inode %ld, lblk %d, len %d\n",
+			inode->i_ino, le32_to_cpu(lrange->fc_lblk),
+			le32_to_cpu(lrange->fc_len));
+	while (remaining > 0) {
+		map.m_lblk = cur;
+		map.m_len = remaining;
+
+		ret = ext4_map_blocks(NULL, inode, &map, 0);
+		if (ret < 0) {
+			iput(inode);
+			return 0;
+		}
+		if (ret > 0) {
+			remaining -= ret;
+			cur += ret;
+			ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
+		} else {
+			remaining -= map.m_len;
+			cur += map.m_len;
+		}
+	}
+
+	ret = ext4_punch_hole(inode,
+		le32_to_cpu(lrange->fc_lblk) << sb->s_blocksize_bits,
+		le32_to_cpu(lrange->fc_len) <<  sb->s_blocksize_bits);
+	if (ret)
+		jbd_debug(1, "ext4_punch_hole returned %d", ret);
+	ext4_ext_replay_shrink_inode(inode,
+		i_size_read(inode) >> sb->s_blocksize_bits);
+	ext4_mark_inode_dirty(NULL, inode);
+	iput(inode);
+
+	return 0;
+}
+
+static inline const char *tag2str(u16 tag)
+{
+	switch (tag) {
+	case EXT4_FC_TAG_LINK:
+		return "TAG_ADD_ENTRY";
+	case EXT4_FC_TAG_UNLINK:
+		return "TAG_DEL_ENTRY";
+	case EXT4_FC_TAG_ADD_RANGE:
+		return "TAG_ADD_RANGE";
+	case EXT4_FC_TAG_CREAT:
+		return "TAG_CREAT_DENTRY";
+	case EXT4_FC_TAG_DEL_RANGE:
+		return "TAG_DEL_RANGE";
+	case EXT4_FC_TAG_INODE:
+		return "TAG_INODE";
+	case EXT4_FC_TAG_PAD:
+		return "TAG_PAD";
+	case EXT4_FC_TAG_TAIL:
+		return "TAG_TAIL";
+	case EXT4_FC_TAG_HEAD:
+		return "TAG_HEAD";
+	default:
+		return "TAG_ERROR";
+	}
+}
+
+static void ext4_fc_set_bitmaps_and_counters(struct super_block *sb)
+{
+	struct ext4_fc_replay_state *state;
+	struct inode *inode;
+	struct ext4_ext_path *path = NULL;
+	struct ext4_map_blocks map;
+	int i, ret, j;
+	ext4_lblk_t cur, end;
+
+	state = &EXT4_SB(sb)->s_fc_replay_state;
+	for (i = 0; i < state->fc_modified_inodes_used; i++) {
+		inode = ext4_iget(sb, state->fc_modified_inodes[i],
+			EXT4_IGET_NORMAL);
+		if (IS_ERR_OR_NULL(inode)) {
+			jbd_debug(1, "Inode %d not found.",
+				state->fc_modified_inodes[i]);
+			continue;
+		}
+		cur = 0;
+		end = EXT_MAX_BLOCKS;
+		while (cur < end) {
+			map.m_lblk = cur;
+			map.m_len = end - cur;
+
+			ret = ext4_map_blocks(NULL, inode, &map, 0);
+			if (ret < 0)
+				break;
+
+			if (ret > 0) {
+				path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
+				if (!IS_ERR_OR_NULL(path)) {
+					for (j = 0; j < path->p_depth; j++)
+						ext4_mb_mark_bb(inode->i_sb,
+							path[j].p_block, 1, 1);
+					ext4_ext_drop_refs(path);
+					kfree(path);
+				}
+				cur += ret;
+				ext4_mb_mark_bb(inode->i_sb, map.m_pblk,
+							map.m_len, 1);
+			} else {
+				cur = cur + (map.m_len ? map.m_len : 1);
+			}
+		}
+		iput(inode);
+	}
+}
+
+/*
+ * Check if block is in excluded regions for block allocation. The simple
+ * allocator that runs during replay phase is calls this function to see
+ * if it is okay to use a block.
+ */
+bool ext4_fc_replay_check_excluded(struct super_block *sb, ext4_fsblk_t blk)
+{
+	int i;
+	struct ext4_fc_replay_state *state;
+
+	state = &EXT4_SB(sb)->s_fc_replay_state;
+	for (i = 0; i < state->fc_regions_valid; i++) {
+		if (state->fc_regions[i].ino == 0 ||
+			state->fc_regions[i].len == 0)
+			continue;
+		if (blk >= state->fc_regions[i].pblk &&
+		    blk < state->fc_regions[i].pblk + state->fc_regions[i].len)
+			return true;
+	}
+	return false;
+}
+
+/* Cleanup function called after replay */
+void ext4_fc_replay_cleanup(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	sbi->s_mount_state &= ~EXT4_FC_REPLAY;
+	kfree(sbi->s_fc_replay_state.fc_regions);
+	kfree(sbi->s_fc_replay_state.fc_modified_inodes);
+}
+
+/*
+ * Recovery Scan phase handler
+ *
+ * This function is called during the scan phase and is responsible
+ * for doing following things:
+ * - Make sure the fast commit area has valid tags for replay
+ * - Count number of tags that need to be replayed by the replay handler
+ * - Verify CRC
+ * - Create a list of excluded blocks for allocation during replay phase
+ *
+ * This function returns JBD2_FC_REPLAY_CONTINUE to indicate that SCAN is
+ * incomplete and JBD2 should send more blocks. It returns JBD2_FC_REPLAY_STOP
+ * to indicate that scan has finished and JBD2 can now start replay phase.
+ * It returns a negative error to indicate that there was an error. At the end
+ * of a successful scan phase, sbi->s_fc_replay_state.fc_replay_num_tags is set
+ * to indicate the number of tags that need to replayed during the replay phase.
+ */
+static int ext4_fc_replay_scan(journal_t *journal,
+				struct buffer_head *bh, int off,
+				tid_t expected_tid)
+{
+	struct super_block *sb = journal->j_private;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_fc_replay_state *state;
+	int ret = JBD2_FC_REPLAY_CONTINUE;
+	struct ext4_fc_add_range *ext;
+	struct ext4_fc_tl *tl;
+	struct ext4_fc_tail *tail;
+	__u8 *start, *end;
+	struct ext4_fc_head *head;
+	struct ext4_extent *ex;
+
+	state = &sbi->s_fc_replay_state;
+
+	start = (u8 *)bh->b_data;
+	end = (__u8 *)bh->b_data + journal->j_blocksize - 1;
+
+	if (state->fc_replay_expected_off == 0) {
+		state->fc_cur_tag = 0;
+		state->fc_replay_num_tags = 0;
+		state->fc_crc = 0;
+		state->fc_regions = NULL;
+		state->fc_regions_valid = state->fc_regions_used =
+			state->fc_regions_size = 0;
+		/* Check if we can stop early */
+		if (le16_to_cpu(((struct ext4_fc_tl *)start)->fc_tag)
+			!= EXT4_FC_TAG_HEAD)
+			return 0;
+	}
+
+	if (off != state->fc_replay_expected_off) {
+		ret = -EFSCORRUPTED;
+		goto out_err;
+	}
+
+	state->fc_replay_expected_off++;
+	fc_for_each_tl(start, end, tl) {
+		jbd_debug(3, "Scan phase, tag:%s, blk %lld\n",
+			  tag2str(le16_to_cpu(tl->fc_tag)), bh->b_blocknr);
+		switch (le16_to_cpu(tl->fc_tag)) {
+		case EXT4_FC_TAG_ADD_RANGE:
+			ext = (struct ext4_fc_add_range *)ext4_fc_tag_val(tl);
+			ex = (struct ext4_extent *)&ext->fc_ex;
+			ret = ext4_fc_record_regions(sb,
+				le32_to_cpu(ext->fc_ino),
+				le32_to_cpu(ex->ee_block), ext4_ext_pblock(ex),
+				ext4_ext_get_actual_len(ex));
+			if (ret < 0)
+				break;
+			ret = JBD2_FC_REPLAY_CONTINUE;
+			fallthrough;
+		case EXT4_FC_TAG_DEL_RANGE:
+		case EXT4_FC_TAG_LINK:
+		case EXT4_FC_TAG_UNLINK:
+		case EXT4_FC_TAG_CREAT:
+		case EXT4_FC_TAG_INODE:
+		case EXT4_FC_TAG_PAD:
+			state->fc_cur_tag++;
+			state->fc_crc = ext4_chksum(sbi, state->fc_crc, tl,
+					sizeof(*tl) + ext4_fc_tag_len(tl));
+			break;
+		case EXT4_FC_TAG_TAIL:
+			state->fc_cur_tag++;
+			tail = (struct ext4_fc_tail *)ext4_fc_tag_val(tl);
+			state->fc_crc = ext4_chksum(sbi, state->fc_crc, tl,
+						sizeof(*tl) +
+						offsetof(struct ext4_fc_tail,
+						fc_crc));
+			if (le32_to_cpu(tail->fc_tid) == expected_tid &&
+				le32_to_cpu(tail->fc_crc) == state->fc_crc) {
+				state->fc_replay_num_tags = state->fc_cur_tag;
+				state->fc_regions_valid =
+					state->fc_regions_used;
+			} else {
+				ret = state->fc_replay_num_tags ?
+					JBD2_FC_REPLAY_STOP : -EFSBADCRC;
+			}
+			state->fc_crc = 0;
+			break;
+		case EXT4_FC_TAG_HEAD:
+			head = (struct ext4_fc_head *)ext4_fc_tag_val(tl);
+			if (le32_to_cpu(head->fc_features) &
+				~EXT4_FC_SUPPORTED_FEATURES) {
+				ret = -EOPNOTSUPP;
+				break;
+			}
+			if (le32_to_cpu(head->fc_tid) != expected_tid) {
+				ret = JBD2_FC_REPLAY_STOP;
+				break;
+			}
+			state->fc_cur_tag++;
+			state->fc_crc = ext4_chksum(sbi, state->fc_crc, tl,
+					sizeof(*tl) + ext4_fc_tag_len(tl));
+			break;
+		default:
+			ret = state->fc_replay_num_tags ?
+				JBD2_FC_REPLAY_STOP : -ECANCELED;
+		}
+		if (ret < 0 || ret == JBD2_FC_REPLAY_STOP)
+			break;
+	}
+
+out_err:
+	trace_ext4_fc_replay_scan(sb, ret, off);
+	return ret;
+}
+
+/*
+ * Main recovery path entry point.
+ * The meaning of return codes is similar as above.
+ */
+static int ext4_fc_replay(journal_t *journal, struct buffer_head *bh,
+				enum passtype pass, int off, tid_t expected_tid)
+{
+	struct super_block *sb = journal->j_private;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_fc_tl *tl;
+	__u8 *start, *end;
+	int ret = JBD2_FC_REPLAY_CONTINUE;
+	struct ext4_fc_replay_state *state = &sbi->s_fc_replay_state;
+	struct ext4_fc_tail *tail;
+
+	if (pass == PASS_SCAN) {
+		state->fc_current_pass = PASS_SCAN;
+		return ext4_fc_replay_scan(journal, bh, off, expected_tid);
+	}
+
+	if (state->fc_current_pass != pass) {
+		state->fc_current_pass = pass;
+		sbi->s_mount_state |= EXT4_FC_REPLAY;
+	}
+	if (!sbi->s_fc_replay_state.fc_replay_num_tags) {
+		jbd_debug(1, "Replay stops\n");
+		ext4_fc_set_bitmaps_and_counters(sb);
+		return 0;
+	}
+
+#ifdef CONFIG_EXT4_DEBUG
+	if (sbi->s_fc_debug_max_replay && off >= sbi->s_fc_debug_max_replay) {
+		pr_warn("Dropping fc block %d because max_replay set\n", off);
+		return JBD2_FC_REPLAY_STOP;
+	}
+#endif
+
+	start = (u8 *)bh->b_data;
+	end = (__u8 *)bh->b_data + journal->j_blocksize - 1;
+
+	fc_for_each_tl(start, end, tl) {
+		if (state->fc_replay_num_tags == 0) {
+			ret = JBD2_FC_REPLAY_STOP;
+			ext4_fc_set_bitmaps_and_counters(sb);
+			break;
+		}
+		jbd_debug(3, "Replay phase, tag:%s\n",
+				tag2str(le16_to_cpu(tl->fc_tag)));
+		state->fc_replay_num_tags--;
+		switch (le16_to_cpu(tl->fc_tag)) {
+		case EXT4_FC_TAG_LINK:
+			ret = ext4_fc_replay_link(sb, tl);
+			break;
+		case EXT4_FC_TAG_UNLINK:
+			ret = ext4_fc_replay_unlink(sb, tl);
+			break;
+		case EXT4_FC_TAG_ADD_RANGE:
+			ret = ext4_fc_replay_add_range(sb, tl);
+			break;
+		case EXT4_FC_TAG_CREAT:
+			ret = ext4_fc_replay_create(sb, tl);
+			break;
+		case EXT4_FC_TAG_DEL_RANGE:
+			ret = ext4_fc_replay_del_range(sb, tl);
+			break;
+		case EXT4_FC_TAG_INODE:
+			ret = ext4_fc_replay_inode(sb, tl);
+			break;
+		case EXT4_FC_TAG_PAD:
+			trace_ext4_fc_replay(sb, EXT4_FC_TAG_PAD, 0,
+				ext4_fc_tag_len(tl), 0);
+			break;
+		case EXT4_FC_TAG_TAIL:
+			trace_ext4_fc_replay(sb, EXT4_FC_TAG_TAIL, 0,
+				ext4_fc_tag_len(tl), 0);
+			tail = (struct ext4_fc_tail *)ext4_fc_tag_val(tl);
+			WARN_ON(le32_to_cpu(tail->fc_tid) != expected_tid);
+			break;
+		case EXT4_FC_TAG_HEAD:
+			break;
+		default:
+			trace_ext4_fc_replay(sb, le16_to_cpu(tl->fc_tag), 0,
+				ext4_fc_tag_len(tl), 0);
+			ret = -ECANCELED;
+			break;
+		}
+		if (ret < 0)
+			break;
+		ret = JBD2_FC_REPLAY_CONTINUE;
+	}
+	return ret;
+}
+
+void ext4_fc_init(struct super_block *sb, journal_t *journal)
+{
+	/*
+	 * We set replay callback even if fast commit disabled because we may
+	 * could still have fast commit blocks that need to be replayed even if
+	 * fast commit has now been turned off.
+	 */
+	journal->j_fc_replay_callback = ext4_fc_replay;
+	if (!test_opt2(sb, JOURNAL_FAST_COMMIT))
+		return;
+	journal->j_fc_cleanup_callback = ext4_fc_cleanup;
+	if (jbd2_fc_init(journal, EXT4_NUM_FC_BLKS)) {
+		pr_warn("Error while enabling fast commits, turning off.");
+		ext4_clear_feature_fast_commit(sb);
+	}
+}
+
+const char *fc_ineligible_reasons[] = {
+	"Extended attributes changed",
+	"Cross rename",
+	"Journal flag changed",
+	"Insufficient memory",
+	"Swap boot",
+	"Resize",
+	"Dir renamed",
+	"Falloc range op",
+	"FC Commit Failed"
+};
+
+int ext4_fc_info_show(struct seq_file *seq, void *v)
+{
+	struct ext4_sb_info *sbi = EXT4_SB((struct super_block *)seq->private);
+	struct ext4_fc_stats *stats = &sbi->s_fc_stats;
+	int i;
+
+	if (v != SEQ_START_TOKEN)
+		return 0;
+
+	seq_printf(seq,
+		"fc stats:\n%ld commits\n%ld ineligible\n%ld numblks\n%lluus avg_commit_time\n",
+		   stats->fc_num_commits, stats->fc_ineligible_commits,
+		   stats->fc_numblks,
+		   div_u64(sbi->s_fc_avg_commit_time, 1000));
+	seq_puts(seq, "Ineligible reasons:\n");
+	for (i = 0; i < EXT4_FC_REASON_MAX; i++)
+		seq_printf(seq, "\"%s\":\t%d\n", fc_ineligible_reasons[i],
+			stats->fc_ineligible_reason_count[i]);
+
+	return 0;
+}
+
+int __init ext4_fc_init_dentry_cache(void)
+{
+	ext4_fc_dentry_cachep = KMEM_CACHE(ext4_fc_dentry_update,
+					   SLAB_RECLAIM_ACCOUNT);
+
+	if (ext4_fc_dentry_cachep == NULL)
+		return -ENOMEM;
+
+	return 0;
+}

fs/ext4/fast_commit.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __FAST_COMMIT_H__
+#define __FAST_COMMIT_H__
+
+/* Number of blocks in journal area to allocate for fast commits */
+#define EXT4_NUM_FC_BLKS		256
+
+/* Fast commit tags */
+#define EXT4_FC_TAG_ADD_RANGE		0x0001
+#define EXT4_FC_TAG_DEL_RANGE		0x0002
+#define EXT4_FC_TAG_CREAT		0x0003
+#define EXT4_FC_TAG_LINK		0x0004
+#define EXT4_FC_TAG_UNLINK		0x0005
+#define EXT4_FC_TAG_INODE		0x0006
+#define EXT4_FC_TAG_PAD			0x0007
+#define EXT4_FC_TAG_TAIL		0x0008
+#define EXT4_FC_TAG_HEAD		0x0009
+
+#define EXT4_FC_SUPPORTED_FEATURES	0x0
+
+/* On disk fast commit tlv value structures */
+
+/* Fast commit on disk tag length structure */
+struct ext4_fc_tl {
+	__le16 fc_tag;
+	__le16 fc_len;
+};
+
+/* Value structure for tag EXT4_FC_TAG_HEAD. */
+struct ext4_fc_head {
+	__le32 fc_features;
+	__le32 fc_tid;
+};
+
+/* Value structure for EXT4_FC_TAG_ADD_RANGE. */
+struct ext4_fc_add_range {
+	__le32 fc_ino;
+	__u8 fc_ex[12];
+};
+
+/* Value structure for tag EXT4_FC_TAG_DEL_RANGE. */
+struct ext4_fc_del_range {
+	__le32 fc_ino;
+	__le32 fc_lblk;
+	__le32 fc_len;
+};
+
+/*
+ * This is the value structure for tags EXT4_FC_TAG_CREAT, EXT4_FC_TAG_LINK
+ * and EXT4_FC_TAG_UNLINK.
+ */
+struct ext4_fc_dentry_info {
+	__le32 fc_parent_ino;
+	__le32 fc_ino;
+	u8 fc_dname[0];
+};
+
+/* Value structure for EXT4_FC_TAG_INODE and EXT4_FC_TAG_INODE_PARTIAL. */
+struct ext4_fc_inode {
+	__le32 fc_ino;
+	__u8 fc_raw_inode[0];
+};
+
+/* Value structure for tag EXT4_FC_TAG_TAIL. */
+struct ext4_fc_tail {
+	__le32 fc_tid;
+	__le32 fc_crc;
+};
+
+/*
+ * In memory list of dentry updates that are performed on the file
+ * system used by fast commit code.
+ */
+struct ext4_fc_dentry_update {
+	int fcd_op;		/* Type of update create / unlink / link */
+	int fcd_parent;		/* Parent inode number */
+	int fcd_ino;		/* Inode number */
+	struct qstr fcd_name;	/* Dirent name */
+	unsigned char fcd_iname[DNAME_INLINE_LEN];	/* Dirent name string */
+	struct list_head fcd_list;
+};
+
+/*
+ * Fast commit reason codes
+ */
+enum {
+	/*
+	 * Commit status codes:
+	 */
+	EXT4_FC_REASON_OK = 0,
+	EXT4_FC_REASON_INELIGIBLE,
+	EXT4_FC_REASON_ALREADY_COMMITTED,
+	EXT4_FC_REASON_FC_START_FAILED,
+	EXT4_FC_REASON_FC_FAILED,
+
+	/*
+	 * Fast commit ineligiblity reasons:
+	 */
+	EXT4_FC_REASON_XATTR = 0,
+	EXT4_FC_REASON_CROSS_RENAME,
+	EXT4_FC_REASON_JOURNAL_FLAG_CHANGE,
+	EXT4_FC_REASON_MEM,
+	EXT4_FC_REASON_SWAP_BOOT,
+	EXT4_FC_REASON_RESIZE,
+	EXT4_FC_REASON_RENAME_DIR,
+	EXT4_FC_REASON_FALLOC_RANGE,
+	EXT4_FC_COMMIT_FAILED,
+	EXT4_FC_REASON_MAX
+};
+
+struct ext4_fc_stats {
+	unsigned int fc_ineligible_reason_count[EXT4_FC_REASON_MAX];
+	unsigned long fc_num_commits;
+	unsigned long fc_ineligible_commits;
+	unsigned long fc_numblks;
+};
+
+#define EXT4_FC_REPLAY_REALLOC_INCREMENT	4
+
+/*
+ * Physical block regions added to different inodes due to fast commit
+ * recovery. These are set during the SCAN phase. During the replay phase,
+ * our allocator excludes these from its allocation. This ensures that
+ * we don't accidentally allocating a block that is going to be used by
+ * another inode.
+ */
+struct ext4_fc_alloc_region {
+	ext4_lblk_t lblk;
+	ext4_fsblk_t pblk;
+	int ino, len;
+};
+
+/*
+ * Fast commit replay state.
+ */
+struct ext4_fc_replay_state {
+	int fc_replay_num_tags;
+	int fc_replay_expected_off;
+	int fc_current_pass;
+	int fc_cur_tag;
+	int fc_crc;
+	struct ext4_fc_alloc_region *fc_regions;
+	int fc_regions_size, fc_regions_used, fc_regions_valid;
+	int *fc_modified_inodes;
+	int fc_modified_inodes_used, fc_modified_inodes_size;
+};
+
+#define region_last(__region) (((__region)->lblk) + ((__region)->len) - 1)
+
+#define fc_for_each_tl(__start, __end, __tl)				\
+	for (tl = (struct ext4_fc_tl *)start;				\
+		(u8 *)tl < (u8 *)end;					\
+		tl = (struct ext4_fc_tl *)((u8 *)tl +			\
+					sizeof(struct ext4_fc_tl) +	\
+					+ le16_to_cpu(tl->fc_len)))
+
+
+#endif /* __FAST_COMMIT_H__ */

fs/ext4/file.c

···
 	if (iocb->ki_flags & IOCB_NOWAIT)
 		return -EOPNOTSUPP;
 
+	ext4_fc_start_update(inode);
 	inode_lock(inode);
 	ret = ext4_write_checks(iocb, from);
 	if (ret <= 0)
···
 
 out:
 	inode_unlock(inode);
+	ext4_fc_stop_update(inode);
 	if (likely(ret > 0)) {
 		iocb->ki_pos += ret;
 		ret = generic_write_sync(iocb, ret);
···
 			goto out;
 		}
 
+		ext4_fc_start_update(inode);
 		ret = ext4_orphan_add(handle, inode);
+		ext4_fc_stop_update(inode);
 		if (ret) {
 			ext4_journal_stop(handle);
 			goto out;
···
 #endif
 	if (iocb->ki_flags & IOCB_DIRECT)
 		return ext4_dio_write_iter(iocb, from);
-
-	return ext4_buffered_write_iter(iocb, from);
+	else
+		return ext4_buffered_write_iter(iocb, from);
 }
 
 #ifdef CONFIG_FS_DAX
···
 	if (!daxdev_mapping_supported(vma, dax_dev))
 		return -EOPNOTSUPP;
 
+	ext4_fc_start_update(inode);
 	file_accessed(file);
 	if (IS_DAX(file_inode(file))) {
 		vma->vm_ops = &ext4_dax_vm_ops;
···
 	} else {
 		vma->vm_ops = &ext4_file_vm_ops;
 	}
+	ext4_fc_stop_update(inode);
 	return 0;
 }
 
···
 			return ret;
 	}
 
-	filp->f_mode |= FMODE_NOWAIT;
+	filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
 	return dquot_file_open(inode, filp);
 }
 

fs/ext4/fsmap.c

···
 
 	/* Are we just counting mappings? */
 	if (info->gfi_head->fmh_count == 0) {
+		if (info->gfi_head->fmh_entries == UINT_MAX)
+			return EXT4_QUERY_RANGE_ABORT;
+
 		if (rec_fsblk > info->gfi_next_fsblk)
 			info->gfi_head->fmh_entries++;
 
···
 	if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX ||
 	    fm->fmr_device == new_encode_dev(sb->s_bdev->bd_dev))
 		return true;
-	if (EXT4_SB(sb)->journal_bdev &&
-	    fm->fmr_device == new_encode_dev(EXT4_SB(sb)->journal_bdev->bd_dev))
+	if (EXT4_SB(sb)->s_journal_bdev &&
+	    fm->fmr_device == new_encode_dev(EXT4_SB(sb)->s_journal_bdev->bd_dev))
 		return true;
 	return false;
 }
···
 	memset(handlers, 0, sizeof(handlers));
 	handlers[0].gfd_dev = new_encode_dev(sb->s_bdev->bd_dev);
 	handlers[0].gfd_fn = ext4_getfsmap_datadev;
-	if (EXT4_SB(sb)->journal_bdev) {
+	if (EXT4_SB(sb)->s_journal_bdev) {
 		handlers[1].gfd_dev = new_encode_dev(
-				EXT4_SB(sb)->journal_bdev->bd_dev);
+				EXT4_SB(sb)->s_journal_bdev->bd_dev);
 		handlers[1].gfd_fn = ext4_getfsmap_logdev;
 	}
 

fs/ext4/fsync.c

···
 	    !jbd2_trans_will_send_data_barrier(journal, commit_tid))
 		*needs_barrier = true;
 
-	return jbd2_complete_transaction(journal, commit_tid);
+	return ext4_fc_commit(journal, commit_tid);
 }
 
 /*
···
 
 	ret = file_write_and_wait_range(file, start, end);
 	if (ret)
-		return ret;
+		goto out;
 
 	/*
 	 * data=writeback,ordered:

fs/ext4/ialloc.c

···
 				      struct buffer_head *bh)
 {
 	ext4_fsblk_t	blk;
-	struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
+	struct ext4_group_info *grp;
+
+	if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
+		return 0;
+
+	grp = ext4_get_group_info(sb, block_group);
 
 	if (buffer_verified(bh))
 		return 0;
···
 	 * submit the buffer_head for reading
 	 */
 	trace_ext4_load_inode_bitmap(sb, block_group);
-	bh->b_end_io = ext4_end_bitmap_read;
-	get_bh(bh);
-	submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
-	wait_on_buffer(bh);
+	ext4_read_bh(bh, REQ_META | REQ_PRIO, ext4_end_bitmap_read);
 	ext4_simulate_fail_bh(sb, bh, EXT4_SIM_IBITMAP_EIO);
 	if (!buffer_uptodate(bh)) {
 		put_bh(bh);
···
 	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 	/* Don't bother if the inode bitmap is corrupt. */
-	grp = ext4_get_group_info(sb, block_group);
 	if (IS_ERR(bitmap_bh)) {
 		fatal = PTR_ERR(bitmap_bh);
 		bitmap_bh = NULL;
 		goto error_return;
 	}
-	if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
-		fatal = -EFSCORRUPTED;
-		goto error_return;
+	if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
+		grp = ext4_get_group_info(sb, block_group);
+		if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
+			fatal = -EFSCORRUPTED;
+			goto error_return;
+		}
 	}
 
 	BUFFER_TRACE(bitmap_bh, "get_write_access");
···
 	return 1;
 }
 
+int ext4_mark_inode_used(struct super_block *sb, int ino)
+{
+	unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
+	struct buffer_head *inode_bitmap_bh = NULL, *group_desc_bh = NULL;
+	struct ext4_group_desc *gdp;
+	ext4_group_t group;
+	int bit;
+	int err = -EFSCORRUPTED;
+
+	if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
+		goto out;
+
+	group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
+	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
+	inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
+	if (IS_ERR(inode_bitmap_bh))
+		return PTR_ERR(inode_bitmap_bh);
+
+	if (ext4_test_bit(bit, inode_bitmap_bh->b_data)) {
+		err = 0;
+		goto out;
+	}
+
+	gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
+	if (!gdp || !group_desc_bh) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	ext4_set_bit(bit, inode_bitmap_bh->b_data);
+
+	BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
+	err = ext4_handle_dirty_metadata(NULL, NULL, inode_bitmap_bh);
+	if (err) {
+		ext4_std_error(sb, err);
+		goto out;
+	}
+	err = sync_dirty_buffer(inode_bitmap_bh);
+	if (err) {
+		ext4_std_error(sb, err);
+		goto out;
+	}
+
+	/* We may have to initialize the block bitmap if it isn't already */
+	if (ext4_has_group_desc_csum(sb) &&
+	    gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+		struct buffer_head *block_bitmap_bh;
+
+		block_bitmap_bh = ext4_read_block_bitmap(sb, group);
+		if (IS_ERR(block_bitmap_bh)) {
+			err = PTR_ERR(block_bitmap_bh);
+			goto out;
+		}
+
+		BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
+		err = ext4_handle_dirty_metadata(NULL, NULL, block_bitmap_bh);
+		sync_dirty_buffer(block_bitmap_bh);
+
+		/* recheck and clear flag under lock if we still need to */
+		ext4_lock_group(sb, group);
+		if (ext4_has_group_desc_csum(sb) &&
+		    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
+			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
+			ext4_free_group_clusters_set(sb, gdp,
+				ext4_free_clusters_after_init(sb, group, gdp));
+			ext4_block_bitmap_csum_set(sb, group, gdp,
+						   block_bitmap_bh);
+			ext4_group_desc_csum_set(sb, group, gdp);
+		}
+		ext4_unlock_group(sb, group);
+		brelse(block_bitmap_bh);
+
+		if (err) {
+			ext4_std_error(sb, err);
+			goto out;
+		}
+	}
+
+	/* Update the relevant bg descriptor fields */
+	if (ext4_has_group_desc_csum(sb)) {
+		int free;
+
+		ext4_lock_group(sb, group); /* while we modify the bg desc */
+		free = EXT4_INODES_PER_GROUP(sb) -
+			ext4_itable_unused_count(sb, gdp);
+		if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
+			gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
+			free = 0;
+		}
+
+		/*
+		 * Check the relative inode number against the last used
+		 * relative inode number in this group. if it is greater
+		 * we need to update the bg_itable_unused count
+		 */
+		if (bit >= free)
+			ext4_itable_unused_set(sb, gdp,
+					(EXT4_INODES_PER_GROUP(sb) - bit - 1));
+	} else {
+		ext4_lock_group(sb, group);
+	}
+
+	ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
+	if (ext4_has_group_desc_csum(sb)) {
+		ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
+					   EXT4_INODES_PER_GROUP(sb) / 8);
+		ext4_group_desc_csum_set(sb, group, gdp);
+	}
+
+	ext4_unlock_group(sb, group);
+	err = ext4_handle_dirty_metadata(NULL, NULL, group_desc_bh);
+	sync_dirty_buffer(group_desc_bh);
+out:
+	return err;
+}
+
 static int ext4_xattr_credits_for_new_inode(struct inode *dir, mode_t mode,
 					    bool encrypt)
 {
···
 	struct inode *ret;
 	ext4_group_t i;
 	ext4_group_t flex_group;
-	struct ext4_group_info *grp;
+	struct ext4_group_info *grp = NULL;
 	bool encrypt = false;
 
 	/* Cannot create files in a deleted directory */
···
 		if (ext4_free_inodes_count(sb, gdp) == 0)
 			goto next_group;
 
-		grp = ext4_get_group_info(sb, group);
-		/* Skip groups with already-known suspicious inode tables */
-		if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
-			goto next_group;
+		if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
+			grp = ext4_get_group_info(sb, group);
+			/*
+			 * Skip groups with already-known suspicious inode
+			 * tables
+			 */
+			if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
+				goto next_group;
+		}
 
 		brelse(inode_bitmap_bh);
 		inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 		/* Skip groups with suspicious inode tables */
-		if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) ||
+		if (((!(sbi->s_mount_state & EXT4_FC_REPLAY))
+		     && EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) ||
 		    IS_ERR(inode_bitmap_bh)) {
 			inode_bitmap_bh = NULL;
 			goto next_group;
···
 			goto next_group;
 		}
 
-		if (!handle) {
+		if ((!(sbi->s_mount_state & EXT4_FC_REPLAY)) && !handle) {
 			BUG_ON(nblocks <= 0);
 			handle = __ext4_journal_start_sb(dir->i_sb, line_no,
 				 handle_type, nblocks, 0,
···
 	/* Update the relevant bg descriptor fields */
 	if (ext4_has_group_desc_csum(sb)) {
 		int free;
-		struct ext4_group_info *grp = ext4_get_group_info(sb, group);
+		struct ext4_group_info *grp = NULL;
 
-		down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
+		if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
+			grp = ext4_get_group_info(sb, group);
+			down_read(&grp->alloc_sem); /*
+						     * protect vs itable
+						     * lazyinit
+						     */
+		}
 		ext4_lock_group(sb, group); /* while we modify the bg desc */
 		free = EXT4_INODES_PER_GROUP(sb) -
 			ext4_itable_unused_count(sb, gdp);
···
 		if (ino > free)
 			ext4_itable_unused_set(sb, gdp,
 					(EXT4_INODES_PER_GROUP(sb) - ino));
-		up_read(&grp->alloc_sem);
+		if (!(sbi->s_mount_state & EXT4_FC_REPLAY))
+			up_read(&grp->alloc_sem);
 	} else {
 		ext4_lock_group(sb, group);
 	}

fs/ext4/indirect.c

···
 		}
 
 		if (!bh_uptodate_or_lock(bh)) {
-			if (bh_submit_read(bh) < 0) {
+			if (ext4_read_bh(bh, 0, NULL) < 0) {
 				put_bh(bh);
 				goto failure;
 			}
···
 	if (ext4_has_feature_bigalloc(inode->i_sb)) {
 		EXT4_ERROR_INODE(inode, "Can't allocate blocks for "
 				 "non-extent mapped inodes with bigalloc");
-		return -EFSCORRUPTED;
+		err = -EFSCORRUPTED;
+		goto out;
 	}
 
 	/* Set up for the direct block allocation */
···
 			}
 
 			/* Go read the buffer for the next level down */
-			bh = sb_bread(inode->i_sb, nr);
+			bh = ext4_sb_bread(inode->i_sb, nr, 0);
 
 			/*
 			 * A read failure? Report error and clear slot
 			 * (should be rare).
 			 */
-			if (!bh) {
-				ext4_error_inode_block(inode, nr, EIO,
+			if (IS_ERR(bh)) {
+				ext4_error_inode_block(inode, nr, -PTR_ERR(bh),
 						       "Read failure");
 				continue;
 			}
···
 			brelse(bh);
 
 			/*
-			 * Everything below this this pointer has been
+			 * Everything below this pointer has been
 			 * released.  Now let this top-of-subtree go.
 			 *
 			 * We want the freeing of this indirect block to be

fs/ext4/inline.c

···
 	if (error)
 		goto out;
 
-	/* Update the xttr entry. */
+	/* Update the xattr entry. */
 	i.value = value;
 	i.value_len = len;
 

fs/ext4/inode.c

···
 	return provided == calculated;
 }
 
-static void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
-				struct ext4_inode_info *ei)
+void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
+			 struct ext4_inode_info *ei)
 {
 	__u32 csum;
 
···
 		return -EFSCORRUPTED;
 
 	/* Lookup extent status tree firstly */
-	if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
+	if (!(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) &&
+	    ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
 		if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
 			map->m_pblk = ext4_es_pblock(&es) +
 					map->m_lblk - es.es_lblk;
···
 			if (ret)
 				return ret;
 		}
+		ext4_fc_track_range(inode, map->m_lblk,
+			    map->m_lblk + map->m_len - 1);
 	}
 
 	if (retval < 0)
···
 	int create = map_flags & EXT4_GET_BLOCKS_CREATE;
 	int err;
 
-	J_ASSERT(handle != NULL || create == 0);
+	J_ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+		 || handle != NULL || create == 0);
 
 	map.m_lblk = block;
 	map.m_len = 1;
···
 		return ERR_PTR(-ENOMEM);
 	if (map.m_flags & EXT4_MAP_NEW) {
 		J_ASSERT(create != 0);
-		J_ASSERT(handle != NULL);
+		J_ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+			 || (handle != NULL));
 
 		/*
 		 * Now that we do not always journal data, we should
···
 			       ext4_lblk_t block, int map_flags)
 {
 	struct buffer_head *bh;
+	int ret;
 
 	bh = ext4_getblk(handle, inode, block, map_flags);
 	if (IS_ERR(bh))
 		return bh;
 	if (!bh || ext4_buffer_uptodate(bh))
 		return bh;
-	ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1, &bh);
-	wait_on_buffer(bh);
-	if (buffer_uptodate(bh))
-		return bh;
-	put_bh(bh);
-	return ERR_PTR(-EIO);
+
+	ret = ext4_read_bh_lock(bh, REQ_META | REQ_PRIO, true);
+	if (ret) {
+		put_bh(bh);
+		return ERR_PTR(ret);
+	}
+	return bh;
 }
 
 /* Read a contiguous batch of blocks. */
···
 	for (i = 0; i < bh_count; i++)
 		/* Note that NULL bhs[i] is valid because of holes. */
 		if (bhs[i] && !ext4_buffer_uptodate(bhs[i]))
-			ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1,
-				    &bhs[i]);
+			ext4_read_bh_lock(bhs[i], REQ_META | REQ_PRIO, false);
 
 	if (!wait)
 		return 0;
···
 		if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
 		    !buffer_unwritten(bh) &&
 		    (block_start < from || block_end > to)) {
-			ll_rw_block(REQ_OP_READ, 0, 1, &bh);
+			ext4_read_bh_lock(bh, 0, false);
 			wait[nr_wait++] = bh;
 		}
 	}
···
 	}
 	if (ret == 0)
 		ret = err;
+	err = ext4_jbd2_inode_add_write(handle, inode, 0, len);
+	if (ret == 0)
+		ret = err;
 	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
 	err = ext4_journal_stop(handle);
 	if (!ret)
···
 					err = PTR_ERR(io_end_vec);
 					goto out;
 				}
-				io_end_vec->offset = mpd->map.m_lblk << blkbits;
+				io_end_vec->offset = (loff_t)mpd->map.m_lblk << blkbits;
 			}
 			*map_bh = true;
 			goto out;
···
 		 * ext4_journal_stop() can wait for transaction commit
 		 * to finish which may depend on writeback of pages to
 		 * complete or on page lock to be released.  In that
-		 * case, we have to wait until after after we have
+		 * case, we have to wait until after we have
 		 * submitted all the IO, released page locks we hold,
 		 * and dropped io_end reference (for extent conversion
 		 * to be able to complete) before stopping the handle.
···
 {
 	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
 
-	if (journal)
-		return !jbd2_transaction_committed(journal,
-					EXT4_I(inode)->i_datasync_tid);
+	if (journal) {
+		if (jbd2_transaction_committed(journal,
+					EXT4_I(inode)->i_datasync_tid))
+			return true;
+		return atomic_read(&EXT4_SB(inode->i_sb)->s_fc_subtid) >=
+			EXT4_I(inode)->i_fc_committed_subtid;
+	}
+
 	/* Any metadata buffers to write? */
 	if (!list_empty(&inode->i_mapping->private_list))
 		return true;
···
 	map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
 			  EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
 
-	if (flags & IOMAP_WRITE)
+	if (flags & IOMAP_WRITE) {
+		/*
+		 * We check here if the blocks are already allocated, then we
+		 * don't need to start a journal txn and we can directly return
+		 * the mapping information. This could boost performance
+		 * especially in multi-threaded overwrite requests.
+		 */
+		if (offset + length <= i_size_read(inode)) {
+			ret = ext4_map_blocks(NULL, inode, &map, 0);
+			if (ret > 0 && (map.m_flags & EXT4_MAP_MAPPED))
+				goto out;
+		}
 		ret = ext4_iomap_alloc(inode, &map, flags);
-	else
+	} else {
 		ret = ext4_map_blocks(NULL, inode, &map, 0);
+	}
 
 	if (ret < 0)
 		return ret;
-
+out:
 	ext4_set_iomap(inode, iomap, &map, offset, length);
 
 	return 0;
···
 	return __set_page_dirty_buffers(page);
 }
 
+static int ext4_iomap_swap_activate(struct swap_info_struct *sis,
+				    struct file *file, sector_t *span)
+{
+	return iomap_swapfile_activate(sis, file, span,
+				       &ext4_iomap_report_ops);
+}
+
 static const struct address_space_operations ext4_aops = {
 	.readpage		= ext4_readpage,
 	.readahead		= ext4_readahead,
···
 	.migratepage		= buffer_migrate_page,
 	.is_partially_uptodate  = block_is_partially_uptodate,
 	.error_remove_page	= generic_error_remove_page,
+	.swap_activate		= ext4_iomap_swap_activate,
 };
 
 static const struct address_space_operations ext4_journalled_aops = {
···
 	.direct_IO		= noop_direct_IO,
 	.is_partially_uptodate  = block_is_partially_uptodate,
 	.error_remove_page	= generic_error_remove_page,
+	.swap_activate		= ext4_iomap_swap_activate,
 };
 
 static const struct address_space_operations ext4_da_aops = {
···
 	.migratepage		= buffer_migrate_page,
 	.is_partially_uptodate  = block_is_partially_uptodate,
 	.error_remove_page	= generic_error_remove_page,
+	.swap_activate		= ext4_iomap_swap_activate,
 };
 
 static const struct address_space_operations ext4_dax_aops = {
···
 	.set_page_dirty		= noop_set_page_dirty,
 	.bmap			= ext4_bmap,
 	.invalidatepage		= noop_invalidatepage,
+	.swap_activate		= ext4_iomap_swap_activate,
 };
 
 void ext4_set_aops(struct inode *inode)
···
 		set_buffer_uptodate(bh);
 
 	if (!buffer_uptodate(bh)) {
-		err = -EIO;
-		ll_rw_block(REQ_OP_READ, 0, 1, &bh);
-		wait_on_buffer(bh);
-		/* Uhhuh. Read error. Complain and punt. */
-		if (!buffer_uptodate(bh))
+		err = ext4_read_bh_lock(bh, 0, true);
+		if (err)
 			goto unlock;
 		if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
 			/* We expect the key to be set. */
···
 
 		up_write(&EXT4_I(inode)->i_data_sem);
 	}
+	ext4_fc_track_range(inode, first_block, stop_block);
 	if (IS_SYNC(inode))
 		ext4_handle_sync(handle);
 
···
  * data in memory that is needed to recreate the on-disk version of this
  * inode.
  */
-static int __ext4_get_inode_loc(struct inode *inode,
-				struct ext4_iloc *iloc, int in_mem)
+static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
+				struct ext4_iloc *iloc, int in_mem,
+				ext4_fsblk_t *ret_block)
 {
 	struct ext4_group_desc	*gdp;
 	struct buffer_head	*bh;
-	struct super_block	*sb = inode->i_sb;
 	ext4_fsblk_t		block;
 	struct blk_plug		plug;
 	int			inodes_per_block, inode_offset;
 
 	iloc->bh = NULL;
-	if (inode->i_ino < EXT4_ROOT_INO ||
-	    inode->i_ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
+	if (ino < EXT4_ROOT_INO ||
+	    ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
 		return -EFSCORRUPTED;
 
-	iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
+	iloc->block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 	gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
 	if (!gdp)
 		return -EIO;
···
 	 * Figure out the offset within the block group inode table
 	 */
 	inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
-	inode_offset = ((inode->i_ino - 1) %
+	inode_offset = ((ino - 1) %
 			EXT4_INODES_PER_GROUP(sb));
 	block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
 	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
···
 	if (!buffer_uptodate(bh)) {
 		lock_buffer(bh);
 
-		/*
-		 * If the buffer has the write error flag, we have failed
-		 * to write out another inode in the same block.  In this
-		 * case, we don't have to read the block because we may
-		 * read the old inode data successfully.
-		 */
-		if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
-			set_buffer_uptodate(bh);
-
-		if (buffer_uptodate(bh)) {
+		if (ext4_buffer_uptodate(bh)) {
 			/* someone brought it uptodate while we waited */
 			unlock_buffer(bh);
 			goto has_buffer;
···
 			if (end > table)
 				end = table;
 			while (b <= end)
-				sb_breadahead_unmovable(sb, b++);
+				ext4_sb_breadahead_unmovable(sb, b++);
 		}
 
 		/*
···
 		 * has in-inode xattrs, or we don't have this inode in memory.
 		 * Read the block from disk.
 		 */
-		trace_ext4_load_inode(inode);
-		get_bh(bh);
-		bh->b_end_io = end_buffer_read_sync;
-		submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
+		trace_ext4_load_inode(sb, ino);
+		ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
 		blk_finish_plug(&plug);
 		wait_on_buffer(bh);
 		if (!buffer_uptodate(bh)) {
 		simulate_eio:
-			ext4_error_inode_block(inode, block, EIO,
-					       "unable to read itable block");
+			if (ret_block)
+				*ret_block = block;
 			brelse(bh);
 			return -EIO;
 		}
···
 	return 0;
 }
 
+static int __ext4_get_inode_loc_noinmem(struct inode *inode,
+					struct ext4_iloc *iloc)
+{
+	ext4_fsblk_t err_blk;
+	int ret;
+
+	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc, 0,
+					&err_blk);
+
+	if (ret == -EIO)
+		ext4_error_inode_block(inode, err_blk, EIO,
+					"unable to read itable block");
+
+	return ret;
+}
+
 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
 {
+	ext4_fsblk_t err_blk;
+	int ret;
+
 	/* We have all inode data except xattrs in memory here. */
-	return __ext4_get_inode_loc(inode, iloc,
-		!ext4_test_inode_state(inode, EXT4_STATE_XATTR));
+	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc,
+		!ext4_test_inode_state(inode, EXT4_STATE_XATTR), &err_blk);
+
+	if (ret == -EIO)
+		ext4_error_inode_block(inode, err_blk, EIO,
+					"unable to read itable block");
+
+	return ret;
+}
+
+
+int ext4_get_fc_inode_loc(struct super_block *sb, unsigned long ino,
+			  struct ext4_iloc *iloc)
+{
+	return __ext4_get_inode_loc(sb, ino, iloc, 0, NULL);
 }
 
 static bool ext4_should_enable_dax(struct inode *inode)
···
 	ei = EXT4_I(inode);
 	iloc.bh = NULL;
 
-	ret = __ext4_get_inode_loc(inode, &iloc, 0);
+	ret = __ext4_get_inode_loc_noinmem(inode, &iloc);
 	if (ret < 0)
 		goto bad_inode;
 	raw_inode = ext4_raw_inode(&iloc);
···
 					      sizeof(gen));
 	}
 
-	if (!ext4_inode_csum_verify(inode, raw_inode, ei) ||
-	    ext4_simulate_fail(sb, EXT4_SIM_INODE_CRC)) {
-		ext4_error_inode_err(inode, function, line, 0, EFSBADCRC,
-				     "iget: checksum invalid");
+	if ((!ext4_inode_csum_verify(inode, raw_inode, ei) ||
+	    ext4_simulate_fail(sb, EXT4_SIM_INODE_CRC)) &&
+	     (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))) {
+		ext4_error_inode_err(inode, function, line, 0,
+				EFSBADCRC, "iget: checksum invalid");
 		ret = -EFSBADCRC;
 		goto bad_inode;
 	}
···
 	for (block = 0; block < EXT4_N_BLOCKS; block++)
 		ei->i_data[block] = raw_inode->i_block[block];
 	INIT_LIST_HEAD(&ei->i_orphan);
+	ext4_fc_init_inode(&ei->vfs_inode);
 
 	/*
 	 * Set transaction id's of transactions that have to be committed
···
 		goto bad_inode;
 	} else if (!ext4_has_inline_data(inode)) {
 		/* validate the block references in the inode */
-		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
-		   (S_ISLNK(inode->i_mode) &&
-		    !ext4_inode_is_fast_symlink(inode))) {
+		if (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) &&
+			(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+			(S_ISLNK(inode->i_mode) &&
+			!ext4_inode_is_fast_symlink(inode)))) {
 			if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 				ret = ext4_ext_check_inode(inode);
 			else
···
 	if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
 		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
 
+	err = ext4_inode_blocks_set(handle, raw_inode, ei);
+	if (err) {
+		spin_unlock(&ei->i_raw_lock);
+		goto out_brelse;
+	}
+
 	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
 	i_uid = i_uid_read(inode);
 	i_gid = i_gid_read(inode);
···
 	EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
 	EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
 
-	err = ext4_inode_blocks_set(handle, raw_inode, ei);
-	if (err) {
-		spin_unlock(&ei->i_raw_lock);
-		goto out_brelse;
-	}
 	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
 	raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
 	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
···
 		if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
 			return 0;
 
-		err = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
+		err = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
 						EXT4_I(inode)->i_sync_tid);
 	} else {
 		struct ext4_iloc iloc;
 
-		err = __ext4_get_inode_loc(inode, &iloc, 0);
+		err = __ext4_get_inode_loc_noinmem(inode, &iloc);
 		if (err)
 			return err;
 		/*
···
 		if (error)
 			return error;
 	}
+	ext4_fc_start_update(inode);
 	if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
 	    (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
 		handle_t *handle;
···
 
 		if (error) {
 			ext4_journal_stop(handle);
+			ext4_fc_stop_update(inode);
 			return error;
 		}
 		/* Update corresponding info in inode so that everything is in
···
 		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
 			struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 
-			if (attr->ia_size > sbi->s_bitmap_maxbytes)
+			if (attr->ia_size > sbi->s_bitmap_maxbytes) {
+				ext4_fc_stop_update(inode);
 				return -EFBIG;
+			}
 		}
-		if (!S_ISREG(inode->i_mode))
+		if (!S_ISREG(inode->i_mode)) {
+			ext4_fc_stop_update(inode);
 			return -EINVAL;
+		}
 
 		if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
 			inode_inc_iversion(inode);
···
 		rc = ext4_break_layouts(inode);
 		if (rc) {
 			up_write(&EXT4_I(inode)->i_mmap_sem);
-			return rc;
+			goto err_out;
 		}
 
 		if (attr->ia_size != inode->i_size) {
···
 				inode->i_mtime = current_time(inode);
 				inode->i_ctime = inode->i_mtime;
 			}
+
+			if (shrink)
+				ext4_fc_track_range(inode,
+					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
+					inode->i_sb->s_blocksize_bits,
+					(oldsize > 0 ? oldsize - 1 : 0) >>
+					inode->i_sb->s_blocksize_bits);
+			else
+				ext4_fc_track_range(
+					inode,
+					(oldsize > 0 ? oldsize - 1 : oldsize) >>
+					inode->i_sb->s_blocksize_bits,
+					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
+					inode->i_sb->s_blocksize_bits);
+
 			down_write(&EXT4_I(inode)->i_data_sem);
 			EXT4_I(inode)->i_disksize = attr->ia_size;
 			rc = ext4_mark_inode_dirty(handle, inode);
···
 		rc = posix_acl_chmod(inode, inode->i_mode);
 
 err_out:
-	ext4_std_error(inode->i_sb, error);
+	if  (error)
+		ext4_std_error(inode->i_sb, error);
 	if (!error)
 		error = rc;
+	ext4_fc_stop_update(inode);
 	return error;
 }
 
···
 		put_bh(iloc->bh);
 		return -EIO;
 	}
+	ext4_fc_track_inode(inode);
+
 	if (IS_I_VERSION(inode))
 		inode_inc_iversion(inode);
 
···
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 
+	ext4_fc_mark_ineligible(inode->i_sb,
+		EXT4_FC_REASON_JOURNAL_FLAG_CHANGE);
 	err = ext4_mark_inode_dirty(handle, inode);
 	ext4_handle_sync(handle);
 	ext4_journal_stop(handle);
···
 	if (err)
 		goto out_ret;
 
+	/*
+	 * On data journalling we skip straight to the transaction handle:
+	 * there's no delalloc; page truncated will be checked later; the
+	 * early return w/ all buffers mapped (calculates size/len) can't
+	 * be used; and there's no dioread_nolock, so only ext4_get_block.
+	 */
+	if (ext4_should_journal_data(inode))
+		goto retry_alloc;
+
 	/* Delalloc case is easy... */
 	if (test_opt(inode->i_sb, DELALLOC) &&
-	    !ext4_should_journal_data(inode) &&
 	    !ext4_nonda_switch(inode->i_sb)) {
 		do {
 			err = block_page_mkwrite(vma, vmf,
···
 	/*
 	 * Return if we have all the buffers mapped. This avoids the need to do
 	 * journal_start/journal_stop which can block and take a long time
+	 *
+	 * This cannot be done for data journalling, as we have to add the
+	 * inode to the transaction's list to writeprotect pages on commit.
 	 */
 	if (page_has_buffers(page)) {
 		if (!ext4_walk_page_buffers(NULL, page_buffers(page),
···
 		ret = VM_FAULT_SIGBUS;
 		goto out;
 	}
-	err = block_page_mkwrite(vma, vmf, get_block);
-	if (!err && ext4_should_journal_data(inode)) {
-		if (ext4_walk_page_buffers(handle, page_buffers(page), 0,
-			  PAGE_SIZE, NULL, do_journal_get_write_access)) {
-			unlock_page(page);
-			ret = VM_FAULT_SIGBUS;
-			ext4_journal_stop(handle);
-			goto out;
+	/*
+	 * Data journalling can't use block_page_mkwrite() because it
+	 * will set_buffer_dirty() before do_journal_get_write_access()
+	 * thus might hit warning messages for dirty metadata buffers.
+	 */
+	if (!ext4_should_journal_data(inode)) {
+		err = block_page_mkwrite(vma, vmf, get_block);
+	} else {
+		lock_page(page);
+		size = i_size_read(inode);
+		/* Page got truncated from under us? */
+		if (page->mapping != mapping || page_offset(page) > size) {
+			ret = VM_FAULT_NOPAGE;
+			goto out_error;
 		}
-		ext4_set_inode_state(inode, EXT4_STATE_JDATA);
+
+		if (page->index == size >> PAGE_SHIFT)
+			len = size & ~PAGE_MASK;
+		else
+			len = PAGE_SIZE;
+
+		err = __block_write_begin(page, 0, len, ext4_get_block);
+		if (!err) {
+			ret = VM_FAULT_SIGBUS;
+			if (ext4_walk_page_buffers(handle, page_buffers(page),
+					0, len, NULL, do_journal_get_write_access))
+				goto out_error;
+			if (ext4_walk_page_buffers(handle, page_buffers(page),
+					0, len, NULL, write_end_fn))
+				goto out_error;
+			if (ext4_jbd2_inode_add_write(handle, inode, 0, len))
+				goto out_error;
+			ext4_set_inode_state(inode, EXT4_STATE_JDATA);
+		} else {
+			unlock_page(page);
+		}
 	}
 	ext4_journal_stop(handle);
 	if (err == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
···
 	up_read(&EXT4_I(inode)->i_mmap_sem);
 	sb_end_pagefault(inode->i_sb);
 	return ret;
+out_error:
+	unlock_page(page);
+	ext4_journal_stop(handle);
+	goto out;
 }
 
 vm_fault_t ext4_filemap_fault(struct vm_fault *vmf)

fs/ext4/ioctl.c

···
 	i_size_write(inode2, isize);
 }
 
-static void reset_inode_seed(struct inode *inode)
+void ext4_reset_inode_seed(struct inode *inode)
 {
 	struct ext4_inode_info *ei = EXT4_I(inode);
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
···
 		err = -EINVAL;
 		goto err_out;
 	}
+	ext4_fc_start_ineligible(sb, EXT4_FC_REASON_SWAP_BOOT);
 
 	/* Protect extent tree against block allocations via delalloc */
 	ext4_double_down_write_data_sem(inode, inode_bl);
···
 
 	inode->i_generation = prandom_u32();
 	inode_bl->i_generation = prandom_u32();
-	reset_inode_seed(inode);
-	reset_inode_seed(inode_bl);
+	ext4_reset_inode_seed(inode);
+	ext4_reset_inode_seed(inode_bl);
 
 	ext4_discard_preallocations(inode, 0);
 
···
 
 err_out1:
 	ext4_journal_stop(handle);
+	ext4_fc_stop_ineligible(sb);
 	ext4_double_up_write_data_sem(inode, inode_bl);
 
 err_out:
···
 	return error;
 }
 
-long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = file_inode(filp);
 	struct super_block *sb = inode->i_sb;
···
 
 		err = ext4_resize_fs(sb, n_blocks_count);
 		if (EXT4_SB(sb)->s_journal) {
+			ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_RESIZE);
 			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
 			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
 			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
···
 	default:
 		return -ENOTTY;
 	}
+}
+
+long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	long ret;
+
+	ext4_fc_start_update(file_inode(filp));
+	ret = __ext4_ioctl(filp, cmd, arg);
+	ext4_fc_stop_update(file_inode(filp));
+
+	return ret;
 }
 
 #ifdef CONFIG_COMPAT

fs/ext4/mballoc.c

···
  * /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
  * terms of number of blocks. If we have mounted the file system with -O
  * stripe=<value> option the group prealloc request is normalized to the
- * the smallest multiple of the stripe value (sbi->s_stripe) which is
+ * smallest multiple of the stripe value (sbi->s_stripe) which is
  * greater than the default mb_group_prealloc.
  *
  * The regular allocator (using the buddy cache) supports a few tunables.
···
 	void *buddy;
 	void *buddy2;
 
-	{
-		static int mb_check_counter;
-		if (mb_check_counter++ % 100 != 0)
-			return 0;
-	}
+	if (e4b->bd_info->bb_check_counter++ % 10)
+		return 0;
 
 	while (order > 1) {
 		buddy = mb_find_buddy(e4b, order, &max);
···
 	}
 }
 
-/*
- * _________________________________________________________________ */
-
 static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side)
 {
 	if (mb_test_bit(*bit + side, bitmap)) {
···
 
 		blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
 		blocknr += EXT4_C2B(sbi, block);
-		ext4_grp_locked_error(sb, e4b->bd_group,
-				      inode ? inode->i_ino : 0,
-				      blocknr,
-				      "freeing already freed block "
-				      "(bit %u); block bitmap corrupt.",
-				      block);
-		ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
+		if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
+			ext4_grp_locked_error(sb, e4b->bd_group,
+					      inode ? inode->i_ino : 0,
+					      blocknr,
+					      "freeing already freed block (bit %u); block bitmap corrupt.",
+					      block);
+			ext4_mark_group_bitmap_corrupted(
+				sb, e4b->bd_group,
 				EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+		}
 		mb_regenerate_buddy(e4b);
 		goto done;
 	}
···
 			/*
 			 * IF we have corrupt bitmap, we won't find any
 			 * free blocks even though group info says we
-			 * we have free blocks
+			 * have free blocks
 			 */
 			ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
 					"%d free clusters as per "
···
 }
 
 /*
+ * Idempotent helper for Ext4 fast commit replay path to set the state of
+ * blocks in bitmaps and update counters.
+ */
+void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
+			int len, int state)
+{
+	struct buffer_head *bitmap_bh = NULL;
+	struct ext4_group_desc *gdp;
+	struct buffer_head *gdp_bh;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	ext4_group_t group;
+	ext4_grpblk_t blkoff;
+	int i, clen, err;
+	int already;
+
+	clen = EXT4_B2C(sbi, len);
+
+	ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
+	bitmap_bh = ext4_read_block_bitmap(sb, group);
+	if (IS_ERR(bitmap_bh)) {
+		err = PTR_ERR(bitmap_bh);
+		bitmap_bh = NULL;
+		goto out_err;
+	}
+
+	err = -EIO;
+	gdp = ext4_get_group_desc(sb, group, &gdp_bh);
+	if (!gdp)
+		goto out_err;
+
+	ext4_lock_group(sb, group);
+	already = 0;
+	for (i = 0; i < clen; i++)
+		if (!mb_test_bit(blkoff + i, bitmap_bh->b_data) == !state)
+			already++;
+
+	if (state)
+		ext4_set_bits(bitmap_bh->b_data, blkoff, clen);
+	else
+		mb_test_and_clear_bits(bitmap_bh->b_data, blkoff, clen);
+	if (ext4_has_group_desc_csum(sb) &&
+	    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
+		gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
+		ext4_free_group_clusters_set(sb, gdp,
+					     ext4_free_clusters_after_init(sb,
+						group, gdp));
+	}
+	if (state)
+		clen = ext4_free_group_clusters(sb, gdp) - clen + already;
+	else
+		clen = ext4_free_group_clusters(sb, gdp) + clen - already;
+
+	ext4_free_group_clusters_set(sb, gdp, clen);
+	ext4_block_bitmap_csum_set(sb, group, gdp, bitmap_bh);
+	ext4_group_desc_csum_set(sb, group, gdp);
+
+	ext4_unlock_group(sb, group);
+
+	if (sbi->s_log_groups_per_flex) {
+		ext4_group_t flex_group = ext4_flex_group(sbi, group);
+
+		atomic64_sub(len,
+			     &sbi_array_rcu_deref(sbi, s_flex_groups,
+						  flex_group)->free_clusters);
+	}
+
+	err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
+	if (err)
+		goto out_err;
+	sync_dirty_buffer(bitmap_bh);
+	err = ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
+	sync_dirty_buffer(gdp_bh);
+
+out_err:
+	brelse(bitmap_bh);
+}
+
+/*
  * here we normalize request for locality group
  * Group request are normalized to s_mb_group_prealloc, which goes to
  * s_strip if we set the same via mount option.
···
 	struct ext4_buddy e4b;
 	int err;
 	int busy = 0;
-	int free = 0;
+	int free, free_total = 0;
 
 	mb_debug(sb, "discard preallocation for group %u\n", group);
 	if (list_empty(&grp->bb_prealloc_list))
···
 
 	INIT_LIST_HEAD(&list);
 repeat:
+	free = 0;
 	ext4_lock_group(sb, group);
-	this_cpu_inc(discard_pa_seq);
 	list_for_each_entry_safe(pa, tmp,
 				&grp->bb_prealloc_list, pa_group_list) {
 		spin_lock(&pa->pa_lock);
···
 		/* seems this one can be freed ... */
 		ext4_mb_mark_pa_deleted(sb, pa);
 
+		if (!free)
+			this_cpu_inc(discard_pa_seq);
+
 		/* we can trust pa_free ... */
 		free += pa->pa_free;
 
···
 
 		list_del(&pa->pa_group_list);
 		list_add(&pa->u.pa_tmp_list, &list);
-	}
-
-	/* if we still need more blocks and some PAs were used, try again */
-	if (free < needed && busy) {
-		busy = 0;
-		ext4_unlock_group(sb, group);
-		cond_resched();
-		goto repeat;
-	}
-
-	/* found anything to free? */
-	if (list_empty(&list)) {
-		BUG_ON(free != 0);
-		mb_debug(sb, "Someone else may have freed PA for this group %u\n",
-			 group);
-		goto out;
 	}
 
 	/* now free all selected PAs */
···
 		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
 	}
 
-out:
+	free_total += free;
+
+	/* if we still need more blocks and some PAs were used, try again */
+	if (free_total < needed && busy) {
+		ext4_unlock_group(sb, group);
+		cond_resched();
+		busy = 0;
+		goto repeat;
+	}
 	ext4_unlock_group(sb, group);
 	ext4_mb_unload_buddy(&e4b);
 	put_bh(bitmap_bh);
 out_dbg:
 	mb_debug(sb, "discarded (%d) blocks preallocated for group %u bb_free (%d)\n",
-		 free, group, grp->bb_free);
-	return free;
+		 free_total, group, grp->bb_free);
+	return free_total;
 }
 
 /*
···
 		/*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
 		return;
 	}
+
+	if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
+		return;
 
 	mb_debug(sb, "discard preallocation for inode %lu\n",
 		 inode->i_ino);
···
 	return ret;
 }
 
+static ext4_fsblk_t ext4_mb_new_blocks_simple(handle_t *handle,
+				struct ext4_allocation_request *ar, int *errp);
+
 /*
  * Main entry point into mballoc to allocate blocks
  * it tries to use preallocation first, then falls back
···
 	sbi = EXT4_SB(sb);
 
 	trace_ext4_request_blocks(ar);
+	if (sbi->s_mount_state & EXT4_FC_REPLAY)
+		return ext4_mb_new_blocks_simple(handle, ar, errp);
 
 	/* Allow to use superuser reservation for quota file */
 	if (ext4_is_quota_file(ar->inode))
···
 	return 0;
 }
 
+/*
+ * Simple allocator for Ext4 fast commit replay path. It searches for blocks
+ * linearly starting at the goal block and also excludes the blocks which
+ * are going to be in use after fast commit replay.
+ */
+static ext4_fsblk_t ext4_mb_new_blocks_simple(handle_t *handle,
+				struct ext4_allocation_request *ar, int *errp)
+{
+	struct buffer_head *bitmap_bh;
+	struct super_block *sb = ar->inode->i_sb;
+	ext4_group_t group;
+	ext4_grpblk_t blkoff;
+	int  i;
+	ext4_fsblk_t goal, block;
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+
+	goal = ar->goal;
+	if (goal < le32_to_cpu(es->s_first_data_block) ||
+			goal >= ext4_blocks_count(es))
+		goal = le32_to_cpu(es->s_first_data_block);
+
+	ar->len = 0;
+	ext4_get_group_no_and_offset(sb, goal, &group, &blkoff);
+	for (; group < ext4_get_groups_count(sb); group++) {
+		bitmap_bh = ext4_read_block_bitmap(sb, group);
+		if (IS_ERR(bitmap_bh)) {
+			*errp = PTR_ERR(bitmap_bh);
+			pr_warn("Failed to read block bitmap\n");
+			return 0;
+		}
+
+		ext4_get_group_no_and_offset(sb,
+			max(ext4_group_first_block_no(sb, group), goal),
+			NULL, &blkoff);
+		i = mb_find_next_zero_bit(bitmap_bh->b_data, sb->s_blocksize,
+						blkoff);
+		brelse(bitmap_bh);
+		if (i >= sb->s_blocksize)
+			continue;
+		if (ext4_fc_replay_check_excluded(sb,
+			ext4_group_first_block_no(sb, group) + i))
+			continue;
+		break;
+	}
+
+	if (group >= ext4_get_groups_count(sb) && i >= sb->s_blocksize)
+		return 0;
+
+	block = ext4_group_first_block_no(sb, group) + i;
+	ext4_mb_mark_bb(sb, block, 1, 1);
+	ar->len = 1;
+
+	return block;
+}
+
+static void ext4_free_blocks_simple(struct inode *inode, ext4_fsblk_t block,
+					unsigned long count)
+{
+	struct buffer_head *bitmap_bh;
+	struct super_block *sb = inode->i_sb;
+	struct ext4_group_desc *gdp;
+	struct buffer_head *gdp_bh;
+	ext4_group_t group;
+	ext4_grpblk_t blkoff;
+	int already_freed = 0, err, i;
+
+	ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
+	bitmap_bh = ext4_read_block_bitmap(sb, group);
+	if (IS_ERR(bitmap_bh)) {
+		err = PTR_ERR(bitmap_bh);
+		pr_warn("Failed to read block bitmap\n");
+		return;
+	}
+	gdp = ext4_get_group_desc(sb, group, &gdp_bh);
+	if (!gdp)
+		return;
+
+	for (i = 0; i < count; i++) {
+		if (!mb_test_bit(blkoff + i, bitmap_bh->b_data))
+			already_freed++;
+	}
+	mb_clear_bits(bitmap_bh->b_data, blkoff, count);
+	err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
+	if (err)
+		return;
+	ext4_free_group_clusters_set(
+		sb, gdp, ext4_free_group_clusters(sb, gdp) +
+		count - already_freed);
+	ext4_block_bitmap_csum_set(sb, group, gdp, bitmap_bh);
+	ext4_group_desc_csum_set(sb, group, gdp);
+	ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
+	sync_dirty_buffer(bitmap_bh);
+	sync_dirty_buffer(gdp_bh);
+	brelse(bitmap_bh);
+}
+
 /**
  * ext4_free_blocks() -- Free given blocks and update quota
  * @handle:		handle for this transaction
···
 	int err = 0;
 	int ret;
 
+	sbi = EXT4_SB(sb);
+
+	if (sbi->s_mount_state & EXT4_FC_REPLAY) {
+		ext4_free_blocks_simple(inode, block, count);
+		return;
+	}
+
 	might_sleep();
 	if (bh) {
 		if (block)
···
 			block = bh->b_blocknr;
 	}
 
-	sbi = EXT4_SB(sb);
 	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
 	    !ext4_inode_block_valid(inode, block, count)) {
 		ext4_error(sb, "Freeing blocks not in datazone - "

fs/ext4/mmp.c

···
 		}
 	}
 
-	get_bh(*bh);
 	lock_buffer(*bh);
-	(*bh)->b_end_io = end_buffer_read_sync;
-	submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, *bh);
-	wait_on_buffer(*bh);
-	if (!buffer_uptodate(*bh)) {
-		ret = -EIO;
+	ret = ext4_read_bh(*bh, REQ_META | REQ_PRIO, NULL);
+	if (ret)
 		goto warn_exit;
-	}
+
 	mmp = (struct mmp_struct *)((*bh)->b_data);
 	if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC) {
 		ret = -EFSCORRUPTED;

fs/ext4/move_extent.c

···
 	for (i = 0; i < nr; i++) {
 		bh = arr[i];
 		if (!bh_uptodate_or_lock(bh)) {
-			err = bh_submit_read(bh);
+			err = ext4_read_bh(bh, 0, NULL);
 			if (err)
 				return err;
 		}

fs/ext4/namei.c

···
  * for checking S_ISDIR(inode) (since the INODE_INDEX feature will not be set
  * on regular files) and to avoid creating huge/slow non-HTREE directories.
  */
-static void ext4_inc_count(handle_t *handle, struct inode *inode)
+static void ext4_inc_count(struct inode *inode)
 {
 	inc_nlink(inode);
 	if (is_dx(inode) &&
···
  * If a directory had nlink == 1, then we should let it be 1. This indicates
  * directory has >EXT4_LINK_MAX subdirs.
  */
-static void ext4_dec_count(handle_t *handle, struct inode *inode)
+static void ext4_dec_count(struct inode *inode)
 {
 	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
 		drop_nlink(inode);
···
 		       bool excl)
 {
 	handle_t *handle;
-	struct inode *inode;
+	struct inode *inode, *inode_save;
 	int err, credits, retries = 0;
 
 	err = dquot_initialize(dir);
···
 		inode->i_op = &ext4_file_inode_operations;
 		inode->i_fop = &ext4_file_operations;
 		ext4_set_aops(inode);
+		inode_save = inode;
+		ihold(inode_save);
 		err = ext4_add_nondir(handle, dentry, &inode);
+		ext4_fc_track_create(inode_save, dentry);
+		iput(inode_save);
 	}
 	if (handle)
 		ext4_journal_stop(handle);
···
 		      umode_t mode, dev_t rdev)
 {
 	handle_t *handle;
-	struct inode *inode;
+	struct inode *inode, *inode_save;
 	int err, credits, retries = 0;
 
 	err = dquot_initialize(dir);
···
 	if (!IS_ERR(inode)) {
 		init_special_inode(inode, inode->i_mode, rdev);
 		inode->i_op = &ext4_special_inode_operations;
+		inode_save = inode;
+		ihold(inode_save);
 		err = ext4_add_nondir(handle, dentry, &inode);
+		if (!err)
+			ext4_fc_track_create(inode_save, dentry);
+		iput(inode_save);
 	}
 	if (handle)
 		ext4_journal_stop(handle);
···
 	return ext4_next_entry(de, blocksize);
 }
 
-static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
+int ext4_init_new_dir(handle_t *handle, struct inode *dir,
 			     struct inode *inode)
 {
 	struct buffer_head *dir_block = NULL;
···
 		iput(inode);
 		goto out_retry;
 	}
-	ext4_inc_count(handle, dir);
+	ext4_fc_track_create(inode, dentry);
+	ext4_inc_count(dir);
+
 	ext4_update_dx_flag(dir);
 	err = ext4_mark_inode_dirty(handle, dir);
 	if (err)
···
 	retval = ext4_mark_inode_dirty(handle, inode);
 	if (retval)
 		goto end_rmdir;
-	ext4_dec_count(handle, dir);
+	ext4_dec_count(dir);
 	ext4_update_dx_flag(dir);
+	ext4_fc_track_unlink(inode, dentry);
 	retval = ext4_mark_inode_dirty(handle, dir);
 
 #ifdef CONFIG_UNICODE
···
 	return retval;
 }
 
-static int ext4_unlink(struct inode *dir, struct dentry *dentry)
+int __ext4_unlink(struct inode *dir, const struct qstr *d_name,
+		  struct inode *inode)
 {
-	int retval;
-	struct inode *inode;
+	int retval = -ENOENT;
 	struct buffer_head *bh;
 	struct ext4_dir_entry_2 *de;
 	handle_t *handle = NULL;
+	int skip_remove_dentry = 0;
 
-	if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
-		return -EIO;
+	bh = ext4_find_entry(dir, d_name, &de, NULL);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
 
-	trace_ext4_unlink_enter(dir, dentry);
-	/* Initialize quotas before so that eventual writes go
-	 * in separate transaction */
-	retval = dquot_initialize(dir);
-	if (retval)
-		goto out_trace;
-	retval = dquot_initialize(d_inode(dentry));
-	if (retval)
-		goto out_trace;
-
-	bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
-	if (IS_ERR(bh)) {
-		retval = PTR_ERR(bh);
-		goto out_trace;
-	}
-	if (!bh) {
-		retval = -ENOENT;
-		goto out_trace;
-	}
-
-	inode = d_inode(dentry);
+	if (!bh)
+		return -ENOENT;
 
 	if (le32_to_cpu(de->inode) != inode->i_ino) {
-		retval = -EFSCORRUPTED;
-		goto out_bh;
+		/*
+		 * It's okay if we find dont find dentry which matches
+		 * the inode. That's because it might have gotten
+		 * renamed to a different inode number
+		 */
+		if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
+			skip_remove_dentry = 1;
+		else
+			goto out_bh;
 	}
 
 	handle = ext4_journal_start(dir, EXT4_HT_DIR,
···
 	if (IS_DIRSYNC(dir))
 		ext4_handle_sync(handle);
 
-	retval = ext4_delete_entry(handle, dir, de, bh);
-	if (retval)
-		goto out_handle;
-	dir->i_ctime = dir->i_mtime = current_time(dir);
-	ext4_update_dx_flag(dir);
-	retval = ext4_mark_inode_dirty(handle, dir);
-	if (retval)
-		goto out_handle;
+	if (!skip_remove_dentry) {
+		retval = ext4_delete_entry(handle, dir, de, bh);
+		if (retval)
+			goto out_handle;
+		dir->i_ctime = dir->i_mtime = current_time(dir);
+		ext4_update_dx_flag(dir);
+		retval = ext4_mark_inode_dirty(handle, dir);
+		if (retval)
+			goto out_handle;
+	} else {
+		retval = 0;
+	}
 	if (inode->i_nlink == 0)
 		ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
-				   dentry->d_name.len, dentry->d_name.name);
+				   d_name->len, d_name->name);
 	else
 		drop_nlink(inode);
 	if (!inode->i_nlink)
···
 	inode->i_ctime = current_time(inode);
 	retval = ext4_mark_inode_dirty(handle, inode);
 
+out_handle:
+	ext4_journal_stop(handle);
+out_bh:
+	brelse(bh);
+	return retval;
+}
+
+static int ext4_unlink(struct inode *dir, struct dentry *dentry)
+{
+	int retval;
+
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
+		return -EIO;
+
+	trace_ext4_unlink_enter(dir, dentry);
+	/*
+	 * Initialize quotas before so that eventual writes go
+	 * in separate transaction
+	 */
+	retval = dquot_initialize(dir);
+	if (retval)
+		goto out_trace;
+	retval = dquot_initialize(d_inode(dentry));
+	if (retval)
+		goto out_trace;
+
+	retval = __ext4_unlink(dir, &dentry->d_name, d_inode(dentry));
+	if (!retval)
+		ext4_fc_track_unlink(d_inode(dentry), dentry);
 #ifdef CONFIG_UNICODE
 	/* VFS negative dentries are incompatible with Encoding and
 	 * Case-insensitiveness. Eventually we'll want avoid
···
 		d_invalidate(dentry);
 #endif
 
-out_handle:
-	ext4_journal_stop(handle);
-out_bh:
-	brelse(bh);
 out_trace:
 	trace_ext4_unlink_exit(dentry, retval);
 	return retval;
···
 		 */
 		drop_nlink(inode);
 		err = ext4_orphan_add(handle, inode);
-		ext4_journal_stop(handle);
+		if (handle)
+			ext4_journal_stop(handle);
 		handle = NULL;
 		if (err)
 			goto err_drop_inode;
···
 	return err;
 }
 
-static int ext4_link(struct dentry *old_dentry,
-		     struct inode *dir, struct dentry *dentry)
+int __ext4_link(struct inode *dir, struct inode *inode, struct dentry *dentry)
 {
 	handle_t *handle;
-	struct inode *inode = d_inode(old_dentry);
 	int err, retries = 0;
-
-	if (inode->i_nlink >= EXT4_LINK_MAX)
-		return -EMLINK;
-
-	err = fscrypt_prepare_link(old_dentry, dir, dentry);
-	if (err)
-		return err;
-
-	if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
-	    (!projid_eq(EXT4_I(dir)->i_projid,
-			EXT4_I(old_dentry->d_inode)->i_projid)))
-		return -EXDEV;
-
-	err = dquot_initialize(dir);
-	if (err)
-		return err;
-
 retry:
 	handle = ext4_journal_start(dir, EXT4_HT_DIR,
 		(EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
···
 		ext4_handle_sync(handle);
 
 	inode->i_ctime = current_time(inode);
-	ext4_inc_count(handle, inode);
+	ext4_inc_count(inode);
 	ihold(inode);
 
 	err = ext4_add_entry(handle, dentry, inode);
 	if (!err) {
+		ext4_fc_track_link(inode, dentry);
 		err = ext4_mark_inode_dirty(handle, inode);
 		/* this can happen only for tmpfile being
 		 * linked the first time
···
 	return err;
 }
 
+static int ext4_link(struct dentry *old_dentry,
+		     struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = d_inode(old_dentry);
+	int err;
+
+	if (inode->i_nlink >= EXT4_LINK_MAX)
+		return -EMLINK;
+
+	err = fscrypt_prepare_link(old_dentry, dir, dentry);
+	if (err)
+		return err;
+
+	if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
+	    (!projid_eq(EXT4_I(dir)->i_projid,
+			EXT4_I(old_dentry->d_inode)->i_projid)))
+		return -EXDEV;
+
+	err = dquot_initialize(dir);
+	if (err)
+		return err;
+	return __ext4_link(dir, inode, dentry);
+}
 
 /*
  * Try to find buffer head where contains the parent block.
···
 {
 	if (ent->dir_nlink_delta) {
 		if (ent->dir_nlink_delta == -1)
-			ext4_dec_count(handle, ent->dir);
+			ext4_dec_count(ent->dir);
 		else
-			ext4_inc_count(handle, ent->dir);
+			ext4_inc_count(ent->dir);
 		ext4_mark_inode_dirty(handle, ent->dir);
 	}
 }
···
 	}
 
 	if (new.inode) {
-		ext4_dec_count(handle, new.inode);
+		ext4_dec_count(new.inode);
 		new.inode->i_ctime = current_time(new.inode);
 	}
 	old.dir->i_ctime = old.dir->i_mtime = current_time(old.dir);
···
 		if (retval)
 			goto end_rename;
 
-		ext4_dec_count(handle, old.dir);
+		ext4_dec_count(old.dir);
 		if (new.inode) {
 			/* checked ext4_empty_dir above, can't have another
 			 * parent, ext4_dec_count() won't work for many-linked
 			 * dirs */
 			clear_nlink(new.inode);
 		} else {
-			ext4_inc_count(handle, new.dir);
+			ext4_inc_count(new.dir);
 			ext4_update_dx_flag(new.dir);
 			retval = ext4_mark_inode_dirty(handle, new.dir);
 			if (unlikely(retval))
···
 	retval = ext4_mark_inode_dirty(handle, old.dir);
 	if (unlikely(retval))
 		goto end_rename;
+
+	if (S_ISDIR(old.inode->i_mode)) {
+		/*
+		 * We disable fast commits here that's because the
+		 * replay code is not yet capable of changing dot dot
+		 * dirents in directories.
+		 */
+		ext4_fc_mark_ineligible(old.inode->i_sb,
+			EXT4_FC_REASON_RENAME_DIR);
+	} else {
+		if (new.inode)
+			ext4_fc_track_unlink(new.inode, new.dentry);
+		ext4_fc_track_link(old.inode, new.dentry);
+		ext4_fc_track_unlink(old.inode, old.dentry);
+	}
+
 	if (new.inode) {
 		retval = ext4_mark_inode_dirty(handle, new.inode);
 		if (unlikely(retval))
···
 	retval = ext4_mark_inode_dirty(handle, new.inode);
 	if (unlikely(retval))
 		goto end_rename;
-
+	ext4_fc_mark_ineligible(new.inode->i_sb,
+				EXT4_FC_REASON_CROSS_RENAME);
 	if (old.dir_bh) {
 		retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
 		if (retval)

fs/ext4/resize.c

···
 
 	BUFFER_TRACE(dind, "get_write_access");
 	err = ext4_journal_get_write_access(handle, dind);
-	if (unlikely(err))
+	if (unlikely(err)) {
 		ext4_std_error(sb, err);
+		goto errout;
+	}
 
 	/* ext4_reserve_inode_write() gets a reference on the iloc */
 	err = ext4_reserve_inode_write(handle, inode, &iloc);
···
 	if (unlikely(!bh))
 		return NULL;
 	if (!bh_uptodate_or_lock(bh)) {
-		if (bh_submit_read(bh) < 0) {
+		if (ext4_read_bh(bh, 0, NULL) < 0) {
 			brelse(bh);
 			return NULL;
 		}
···
 			     o_blocks_count + add, add);
 
 	/* See if the device is actually as big as what was requested */
-	bh = sb_bread(sb, o_blocks_count + add - 1);
-	if (!bh) {
+	bh = ext4_sb_bread(sb, o_blocks_count + add - 1, 0);
+	if (IS_ERR(bh)) {
 		ext4_warning(sb, "can't read last block, resize aborted");
 		return -ENOSPC;
 	}
···
 	int meta_bg;
 
 	/* See if the device is actually as big as what was requested */
-	bh = sb_bread(sb, n_blocks_count - 1);
-	if (!bh) {
+	bh = ext4_sb_bread(sb, n_blocks_count - 1, 0);
+	if (IS_ERR(bh)) {
 		ext4_warning(sb, "can't read last block, resize aborted");
 		return -ENOSPC;
 	}

fs/ext4/super.c

···
 MODULE_ALIAS("ext3");
 #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
 
+
+static inline void __ext4_read_bh(struct buffer_head *bh, int op_flags,
+				  bh_end_io_t *end_io)
+{
+	/*
+	 * buffer's verified bit is no longer valid after reading from
+	 * disk again due to write out error, clear it to make sure we
+	 * recheck the buffer contents.
+	 */
+	clear_buffer_verified(bh);
+
+	bh->b_end_io = end_io ? end_io : end_buffer_read_sync;
+	get_bh(bh);
+	submit_bh(REQ_OP_READ, op_flags, bh);
+}
+
+void ext4_read_bh_nowait(struct buffer_head *bh, int op_flags,
+			 bh_end_io_t *end_io)
+{
+	BUG_ON(!buffer_locked(bh));
+
+	if (ext4_buffer_uptodate(bh)) {
+		unlock_buffer(bh);
+		return;
+	}
+	__ext4_read_bh(bh, op_flags, end_io);
+}
+
+int ext4_read_bh(struct buffer_head *bh, int op_flags, bh_end_io_t *end_io)
+{
+	BUG_ON(!buffer_locked(bh));
+
+	if (ext4_buffer_uptodate(bh)) {
+		unlock_buffer(bh);
+		return 0;
+	}
+
+	__ext4_read_bh(bh, op_flags, end_io);
+
+	wait_on_buffer(bh);
+	if (buffer_uptodate(bh))
+		return 0;
+	return -EIO;
+}
+
+int ext4_read_bh_lock(struct buffer_head *bh, int op_flags, bool wait)
+{
+	if (trylock_buffer(bh)) {
+		if (wait)
+			return ext4_read_bh(bh, op_flags, NULL);
+		ext4_read_bh_nowait(bh, op_flags, NULL);
+		return 0;
+	}
+	if (wait) {
+		wait_on_buffer(bh);
+		if (buffer_uptodate(bh))
+			return 0;
+		return -EIO;
+	}
+	return 0;
+}
+
 /*
- * This works like sb_bread() except it uses ERR_PTR for error
+ * This works like __bread_gfp() except it uses ERR_PTR for error
  * returns.  Currently with sb_bread it's impossible to distinguish
  * between ENOMEM and EIO situations (since both result in a NULL
  * return.
  */
-struct buffer_head *
-ext4_sb_bread(struct super_block *sb, sector_t block, int op_flags)
+static struct buffer_head *__ext4_sb_bread_gfp(struct super_block *sb,
+					       sector_t block, int op_flags,
+					       gfp_t gfp)
 {
-	struct buffer_head *bh = sb_getblk(sb, block);
+	struct buffer_head *bh;
+	int ret;
 
+	bh = sb_getblk_gfp(sb, block, gfp);
 	if (bh == NULL)
 		return ERR_PTR(-ENOMEM);
 	if (ext4_buffer_uptodate(bh))
 		return bh;
-	ll_rw_block(REQ_OP_READ, REQ_META | op_flags, 1, &bh);
-	wait_on_buffer(bh);
-	if (buffer_uptodate(bh))
-		return bh;
-	put_bh(bh);
-	return ERR_PTR(-EIO);
+
+	ret = ext4_read_bh_lock(bh, REQ_META | op_flags, true);
+	if (ret) {
+		put_bh(bh);
+		return ERR_PTR(ret);
+	}
+	return bh;
+}
+
+struct buffer_head *ext4_sb_bread(struct super_block *sb, sector_t block,
+				   int op_flags)
+{
+	return __ext4_sb_bread_gfp(sb, block, op_flags, __GFP_MOVABLE);
+}
+
+struct buffer_head *ext4_sb_bread_unmovable(struct super_block *sb,
+					    sector_t block)
+{
+	return __ext4_sb_bread_gfp(sb, block, 0, 0);
+}
+
+void ext4_sb_breadahead_unmovable(struct super_block *sb, sector_t block)
+{
+	struct buffer_head *bh = sb_getblk_gfp(sb, block, 0);
+
+	if (likely(bh)) {
+		ext4_read_bh_lock(bh, REQ_RAHEAD, false);
+		brelse(bh);
+	}
 }
 
 static int ext4_verify_csum_type(struct super_block *sb,
···
 	if (!ext4_has_metadata_csum(sb))
 		return;
 
+	/*
+	 * Locking the superblock prevents the scenario
+	 * where:
+	 *  1) a first thread pauses during checksum calculation.
+	 *  2) a second thread updates the superblock, recalculates
+	 *     the checksum, and updates s_checksum
+	 *  3) the first thread resumes and finishes its checksum calculation
+	 *     and updates s_checksum with a potentially stale or torn value.
+	 */
+	lock_buffer(EXT4_SB(sb)->s_sbh);
 	es->s_checksum = ext4_superblock_csum(sb, es);
+	unlock_buffer(EXT4_SB(sb)->s_sbh);
 }
 
 ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
···
 		spin_lock(&sbi->s_md_lock);
 	}
 	spin_unlock(&sbi->s_md_lock);
+}
+
+/*
+ * This writepage callback for write_cache_pages()
+ * takes care of a few cases after page cleaning.
+ *
+ * write_cache_pages() already checks for dirty pages
+ * and calls clear_page_dirty_for_io(), which we want,
+ * to write protect the pages.
+ *
+ * However, we may have to redirty a page (see below.)
+ */
+static int ext4_journalled_writepage_callback(struct page *page,
+					      struct writeback_control *wbc,
+					      void *data)
+{
+	transaction_t *transaction = (transaction_t *) data;
+	struct buffer_head *bh, *head;
+	struct journal_head *jh;
+
+	bh = head = page_buffers(page);
+	do {
+		/*
+		 * We have to redirty a page in these cases:
+		 * 1) If buffer is dirty, it means the page was dirty because it
+		 * contains a buffer that needs checkpointing. So the dirty bit
+		 * needs to be preserved so that checkpointing writes the buffer
+		 * properly.
+		 * 2) If buffer is not part of the committing transaction
+		 * (we may have just accidentally come across this buffer because
+		 * inode range tracking is not exact) or if the currently running
+		 * transaction already contains this buffer as well, dirty bit
+		 * needs to be preserved so that the buffer gets writeprotected
+		 * properly on running transaction's commit.
+		 */
+		jh = bh2jh(bh);
+		if (buffer_dirty(bh) ||
+		    (jh && (jh->b_transaction != transaction ||
+			    jh->b_next_transaction))) {
+			redirty_page_for_writepage(wbc, page);
+			goto out;
+		}
+	} while ((bh = bh->b_this_page) != head);
+
+out:
+	return AOP_WRITEPAGE_ACTIVATE;
+}
+
+static int ext4_journalled_submit_inode_data_buffers(struct jbd2_inode *jinode)
+{
+	struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
+	struct writeback_control wbc = {
+		.sync_mode =  WB_SYNC_ALL,
+		.nr_to_write = LONG_MAX,
+		.range_start = jinode->i_dirty_start,
+		.range_end = jinode->i_dirty_end,
+        };
+
+	return write_cache_pages(mapping, &wbc,
+				 ext4_journalled_writepage_callback,
+				 jinode->i_transaction);
+}
+
+static int ext4_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
+{
+	int ret;
+
+	if (ext4_should_journal_data(jinode->i_vfs_inode))
+		ret = ext4_journalled_submit_inode_data_buffers(jinode);
+	else
+		ret = jbd2_journal_submit_inode_data_buffers(jinode);
+
+	return ret;
+}
+
+static int ext4_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
+{
+	int ret = 0;
+
+	if (!ext4_should_journal_data(jinode->i_vfs_inode))
+		ret = jbd2_journal_finish_inode_data_buffers(jinode);
+
+	return ret;
 }
 
 static bool system_going_down(void)
···
 static void ext4_blkdev_remove(struct ext4_sb_info *sbi)
 {
 	struct block_device *bdev;
-	bdev = sbi->journal_bdev;
+	bdev = sbi->s_journal_bdev;
 	if (bdev) {
 		ext4_blkdev_put(bdev);
-		sbi->journal_bdev = NULL;
+		sbi->s_journal_bdev = NULL;
 	}
 }
 
···
 
 	sync_blockdev(sb->s_bdev);
 	invalidate_bdev(sb->s_bdev);
-	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
+	if (sbi->s_journal_bdev && sbi->s_journal_bdev != sb->s_bdev) {
 		/*
 		 * Invalidate the journal device's buffers.  We don't want them
 		 * floating about in memory - the physical journal device may
 		 * hotswapped, and it breaks the `ro-after' testing code.
 		 */
-		sync_blockdev(sbi->journal_bdev);
-		invalidate_bdev(sbi->journal_bdev);
+		sync_blockdev(sbi->s_journal_bdev);
+		invalidate_bdev(sbi->s_journal_bdev);
 		ext4_blkdev_remove(sbi);
 	}
 
···
 	ei->i_datasync_tid = 0;
 	atomic_set(&ei->i_unwritten, 0);
 	INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
+	ext4_fc_init_inode(&ei->vfs_inode);
+	mutex_init(&ei->i_fc_lock);
 	return &ei->vfs_inode;
 }
 
···
 static void ext4_free_in_core_inode(struct inode *inode)
 {
 	fscrypt_free_inode(inode);
+	if (!list_empty(&(EXT4_I(inode)->i_fc_list))) {
+		pr_warn("%s: inode %ld still in fc list",
+			__func__, inode->i_ino);
+	}
 	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
 }
 
···
 	init_rwsem(&ei->i_data_sem);
 	init_rwsem(&ei->i_mmap_sem);
 	inode_init_once(&ei->vfs_inode);
+	ext4_fc_init_inode(&ei->vfs_inode);
 }
 
 static int __init init_inodecache(void)
···
 
 void ext4_clear_inode(struct inode *inode)
 {
+	ext4_fc_del(inode);
 	invalidate_inode_buffers(inode);
 	clear_inode(inode);
 	ext4_discard_preallocations(inode, 0);
···
 	Opt_dioread_nolock, Opt_dioread_lock,
 	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
 	Opt_max_dir_size_kb, Opt_nojournal_checksum, Opt_nombcache,
-	Opt_prefetch_block_bitmaps,
+	Opt_prefetch_block_bitmaps, Opt_no_fc,
+#ifdef CONFIG_EXT4_DEBUG
+	Opt_fc_debug_max_replay,
+#endif
+	Opt_fc_debug_force
 };
 
 static const match_table_t tokens = {
···
 	{Opt_init_itable, "init_itable=%u"},
 	{Opt_init_itable, "init_itable"},
 	{Opt_noinit_itable, "noinit_itable"},
+	{Opt_no_fc, "no_fc"},
+	{Opt_fc_debug_force, "fc_debug_force"},
+#ifdef CONFIG_EXT4_DEBUG
+	{Opt_fc_debug_max_replay, "fc_debug_max_replay=%u"},
+#endif
 	{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
 	{Opt_test_dummy_encryption, "test_dummy_encryption=%s"},
 	{Opt_test_dummy_encryption, "test_dummy_encryption"},
···
 #define MOPT_EXT4_ONLY	(MOPT_NO_EXT2 | MOPT_NO_EXT3)
 #define MOPT_STRING	0x0400
 #define MOPT_SKIP	0x0800
+#define	MOPT_2		0x1000
 
 static const struct mount_opts {
 	int	token;
···
 	{Opt_nombcache, EXT4_MOUNT_NO_MBCACHE, MOPT_SET},
 	{Opt_prefetch_block_bitmaps, EXT4_MOUNT_PREFETCH_BLOCK_BITMAPS,
 	 MOPT_SET},
+	{Opt_no_fc, EXT4_MOUNT2_JOURNAL_FAST_COMMIT,
+	 MOPT_CLEAR | MOPT_2 | MOPT_EXT4_ONLY},
+	{Opt_fc_debug_force, EXT4_MOUNT2_JOURNAL_FAST_COMMIT,
+	 MOPT_SET | MOPT_2 | MOPT_EXT4_ONLY},
+#ifdef CONFIG_EXT4_DEBUG
+	{Opt_fc_debug_max_replay, 0, MOPT_GTE0},
+#endif
 	{Opt_err, 0, 0}
 };
 
···
 		sbi->s_li_wait_mult = arg;
 	} else if (token == Opt_max_dir_size_kb) {
 		sbi->s_max_dir_size_kb = arg;
+#ifdef CONFIG_EXT4_DEBUG
+	} else if (token == Opt_fc_debug_max_replay) {
+		sbi->s_fc_debug_max_replay = arg;
+#endif
 	} else if (token == Opt_stripe) {
 		sbi->s_stripe = arg;
 	} else if (token == Opt_resuid) {
···
 			WARN_ON(1);
 			return -1;
 		}
-		if (arg != 0)
-			sbi->s_mount_opt |= m->mount_opt;
-		else
-			sbi->s_mount_opt &= ~m->mount_opt;
+		if (m->flags & MOPT_2) {
+			if (arg != 0)
+				sbi->s_mount_opt2 |= m->mount_opt;
+			else
+				sbi->s_mount_opt2 &= ~m->mount_opt;
+		} else {
+			if (arg != 0)
+				sbi->s_mount_opt |= m->mount_opt;
+			else
+				sbi->s_mount_opt &= ~m->mount_opt;
+		}
 	}
 	return 1;
 }
···
 	} else if (test_opt2(sb, DAX_INODE)) {
 		SEQ_OPTS_PUTS("dax=inode");
 	}
+
+	if (test_opt2(sb, JOURNAL_FAST_COMMIT))
+		SEQ_OPTS_PUTS("fast_commit");
 
 	ext4_show_quota_options(seq, sb);
 	return 0;
···
 	 * Add the internal journal blocks whether the journal has been
 	 * loaded or not
 	 */
-	if (sbi->s_journal && !sbi->journal_bdev)
+	if (sbi->s_journal && !sbi->s_journal_bdev)
 		overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_maxlen);
 	else if (ext4_has_feature_journal(sb) && !sbi->s_journal && j_inum) {
 		/* j_inum for internal journal is non-zero */
···
 		logical_sb_block = sb_block;
 	}
 
-	if (!(bh = sb_bread_unmovable(sb, logical_sb_block))) {
+	bh = ext4_sb_bread_unmovable(sb, logical_sb_block);
+	if (IS_ERR(bh)) {
 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
+		ret = PTR_ERR(bh);
+		bh = NULL;
 		goto out_fail;
 	}
 	/*
···
 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 	set_opt(sb, POSIX_ACL);
 #endif
+	if (ext4_has_feature_fast_commit(sb))
+		set_opt2(sb, JOURNAL_FAST_COMMIT);
 	/* don't forget to enable journal_csum when metadata_csum is enabled. */
 	if (ext4_has_metadata_csum(sb))
 		set_opt(sb, JOURNAL_CHECKSUM);
···
 		brelse(bh);
 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
 		offset = do_div(logical_sb_block, blocksize);
-		bh = sb_bread_unmovable(sb, logical_sb_block);
-		if (!bh) {
+		bh = ext4_sb_bread_unmovable(sb, logical_sb_block);
+		if (IS_ERR(bh)) {
 			ext4_msg(sb, KERN_ERR,
 			       "Can't read superblock on 2nd try");
+			ret = PTR_ERR(bh);
+			bh = NULL;
 			goto failed_mount;
 		}
 		es = (struct ext4_super_block *)(bh->b_data + offset);
···
 	/* Pre-read the descriptors into the buffer cache */
 	for (i = 0; i < db_count; i++) {
 		block = descriptor_loc(sb, logical_sb_block, i);
-		sb_breadahead_unmovable(sb, block);
+		ext4_sb_breadahead_unmovable(sb, block);
 	}
 
 	for (i = 0; i < db_count; i++) {
 		struct buffer_head *bh;
 
 		block = descriptor_loc(sb, logical_sb_block, i);
-		bh = sb_bread_unmovable(sb, block);
-		if (!bh) {
+		bh = ext4_sb_bread_unmovable(sb, block);
+		if (IS_ERR(bh)) {
 			ext4_msg(sb, KERN_ERR,
 			       "can't read group descriptor %d", i);
 			db_count = i;
+			ret = PTR_ERR(bh);
+			bh = NULL;
 			goto failed_mount2;
 		}
 		rcu_read_lock();
···
 
 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
 	mutex_init(&sbi->s_orphan_lock);
+
+	/* Initialize fast commit stuff */
+	atomic_set(&sbi->s_fc_subtid, 0);
+	atomic_set(&sbi->s_fc_ineligible_updates, 0);
+	INIT_LIST_HEAD(&sbi->s_fc_q[FC_Q_MAIN]);
+	INIT_LIST_HEAD(&sbi->s_fc_q[FC_Q_STAGING]);
+	INIT_LIST_HEAD(&sbi->s_fc_dentry_q[FC_Q_MAIN]);
+	INIT_LIST_HEAD(&sbi->s_fc_dentry_q[FC_Q_STAGING]);
+	sbi->s_fc_bytes = 0;
+	sbi->s_mount_state &= ~EXT4_FC_INELIGIBLE;
+	sbi->s_mount_state &= ~EXT4_FC_COMMITTING;
+	spin_lock_init(&sbi->s_fc_lock);
+	memset(&sbi->s_fc_stats, 0, sizeof(sbi->s_fc_stats));
+	sbi->s_fc_replay_state.fc_regions = NULL;
+	sbi->s_fc_replay_state.fc_regions_size = 0;
+	sbi->s_fc_replay_state.fc_regions_used = 0;
+	sbi->s_fc_replay_state.fc_regions_valid = 0;
+	sbi->s_fc_replay_state.fc_modified_inodes = NULL;
+	sbi->s_fc_replay_state.fc_modified_inodes_size = 0;
+	sbi->s_fc_replay_state.fc_modified_inodes_used = 0;
 
 	sb->s_root = NULL;
 
···
 		sbi->s_def_mount_opt &= ~EXT4_MOUNT_JOURNAL_CHECKSUM;
 		clear_opt(sb, JOURNAL_CHECKSUM);
 		clear_opt(sb, DATA_FLAGS);
+		clear_opt2(sb, JOURNAL_FAST_COMMIT);
 		sbi->s_journal = NULL;
 		needs_recovery = 0;
 		goto no_journal;
···
 	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
 
 	sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
+	sbi->s_journal->j_submit_inode_data_buffers =
+		ext4_journal_submit_inode_data_buffers;
+	sbi->s_journal->j_finish_inode_data_buffers =
+		ext4_journal_finish_inode_data_buffers;
 
 no_journal:
 	if (!test_opt(sb, NO_MBCACHE)) {
···
 			goto failed_mount4a;
 		}
 	}
+	ext4_fc_replay_cleanup(sb);
 
 	ext4_ext_init(sb);
 	err = ext4_mb_init(sb);
···
 	 * used to detect the metadata async write error.
 	 */
 	spin_lock_init(&sbi->s_bdev_wb_lock);
-	if (!sb_rdonly(sb))
-		errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err,
-					 &sbi->s_bdev_wb_err);
+	errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err,
+				 &sbi->s_bdev_wb_err);
 	sb->s_bdev->bd_super = sb;
 	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
 	ext4_orphan_cleanup(sb, es);
···
 
 failed_mount8:
 	ext4_unregister_sysfs(sb);
+	kobject_put(&sbi->s_kobj);
 failed_mount7:
 	ext4_unregister_li_request(sb);
 failed_mount6:
···
 	journal->j_commit_interval = sbi->s_commit_interval;
 	journal->j_min_batch_time = sbi->s_min_batch_time;
 	journal->j_max_batch_time = sbi->s_max_batch_time;
+	ext4_fc_init(sb, journal);
 
 	write_lock(&journal->j_state_lock);
 	if (test_opt(sb, BARRIER))
···
 		goto out_bdev;
 	}
 	journal->j_private = sb;
-	ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1, &journal->j_sb_buffer);
-	wait_on_buffer(journal->j_sb_buffer);
-	if (!buffer_uptodate(journal->j_sb_buffer)) {
+	if (ext4_read_bh_lock(journal->j_sb_buffer, REQ_META | REQ_PRIO, true)) {
 		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
 		goto out_journal;
 	}
···
 			be32_to_cpu(journal->j_superblock->s_nr_users));
 		goto out_journal;
 	}
-	EXT4_SB(sb)->journal_bdev = bdev;
+	EXT4_SB(sb)->s_journal_bdev = bdev;
 	ext4_init_journal_params(sb, journal);
 	return journal;
 
···
 			}
 
 			/*
-			 * Update the original bdev mapping's wb_err value
-			 * which could be used to detect the metadata async
-			 * write error.
-			 */
-			errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err,
-						 &sbi->s_bdev_wb_err);
-
-			/*
 			 * Mounting a RDONLY partition read-write, so reread
 			 * and store the current valid flag.  (It may have
 			 * been changed by e2fsck since we originally mounted
···
 	 * Releasing of existing data is done when we are sure remount will
 	 * succeed.
 	 */
-	if (test_opt(sb, BLOCK_VALIDITY) && !sbi->system_blks) {
+	if (test_opt(sb, BLOCK_VALIDITY) && !sbi->s_system_blks) {
 		err = ext4_setup_system_zone(sb);
 		if (err)
 			goto restore_opts;
···
 		}
 	}
 #endif
-	if (!test_opt(sb, BLOCK_VALIDITY) && sbi->system_blks)
+	if (!test_opt(sb, BLOCK_VALIDITY) && sbi->s_system_blks)
 		ext4_release_system_zone(sb);
 
 	/*
···
 	sbi->s_commit_interval = old_opts.s_commit_interval;
 	sbi->s_min_batch_time = old_opts.s_min_batch_time;
 	sbi->s_max_batch_time = old_opts.s_max_batch_time;
-	if (!test_opt(sb, BLOCK_VALIDITY) && sbi->system_blks)
+	if (!test_opt(sb, BLOCK_VALIDITY) && sbi->s_system_blks)
 		ext4_release_system_zone(sb);
 #ifdef CONFIG_QUOTA
 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
···
 	/* Quotafile not on the same filesystem? */
 	if (path->dentry->d_sb != sb)
 		return -EXDEV;
+
+	/* Quota already enabled for this file? */
+	if (IS_NOQUOTA(d_inode(path->dentry)))
+		return -EBUSY;
+
 	/* Journaling quota? */
 	if (EXT4_SB(sb)->s_qf_names[type]) {
 		/* Quotafile not in fs root? */
···
 	brelse(bh);
 out:
 	if (inode->i_size < off + len) {
+		ext4_fc_track_range(inode,
+			(inode->i_size > 0 ? inode->i_size - 1 : 0)
+				>> inode->i_sb->s_blocksize_bits,
+			(off + len) >> inode->i_sb->s_blocksize_bits);
 		i_size_write(inode, off + len);
 		EXT4_I(inode)->i_disksize = inode->i_size;
 		err2 = ext4_mark_inode_dirty(handle, inode);
···
 	err = init_inodecache();
 	if (err)
 		goto out1;
+
+	err = ext4_fc_init_dentry_cache();
+	if (err)
+		goto out05;
+
 	register_as_ext3();
 	register_as_ext2();
 	err = register_filesystem(&ext4_fs_type);
···
 out:
 	unregister_as_ext2();
 	unregister_as_ext3();
+out05:
 	destroy_inodecache();
 out1:
 	ext4_exit_mballoc();

fs/ext4/sysfs.c

···
 		proc_create_single_data("es_shrinker_info", S_IRUGO,
 				sbi->s_proc, ext4_seq_es_shrinker_info_show,
 				sb);
+		proc_create_single_data("fc_info", 0444, sbi->s_proc,
+					ext4_fc_info_show, sb);
 		proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
 				&ext4_mb_seq_groups_ops, sb);
 	}

fs/ext4/xattr.c

···
 		if (IS_SYNC(inode))
 			ext4_handle_sync(handle);
 	}
+	ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
 
 cleanup:
 	brelse(is.iloc.bh);
···
 		if (error == 0)
 			error = error2;
 	}
+	ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
 
 	return error;
 }
···
 					 error);
 			goto cleanup;
 		}
+		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
 	}
 	error = 0;
 cleanup:

fs/jbd2/commit.c

···
  * use writepages() because with delayed allocation we may be doing
  * block allocation in writepages().
  */
-static int journal_submit_inode_data_buffers(struct address_space *mapping,
-		loff_t dirty_start, loff_t dirty_end)
+int jbd2_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
 {
-	int ret;
+	struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
 	struct writeback_control wbc = {
 		.sync_mode =  WB_SYNC_ALL,
 		.nr_to_write = mapping->nrpages * 2,
-		.range_start = dirty_start,
-		.range_end = dirty_end,
+		.range_start = jinode->i_dirty_start,
+		.range_end = jinode->i_dirty_end,
 	};
 
-	ret = generic_writepages(mapping, &wbc);
-	return ret;
+	/*
+	 * submit the inode data buffers. We use writepage
+	 * instead of writepages. Because writepages can do
+	 * block allocation with delalloc. We need to write
+	 * only allocated blocks here.
+	 */
+	return generic_writepages(mapping, &wbc);
 }
+
+/* Send all the data buffers related to an inode */
+int jbd2_submit_inode_data(struct jbd2_inode *jinode)
+{
+
+	if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
+		return 0;
+
+	trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
+	return jbd2_journal_submit_inode_data_buffers(jinode);
+
+}
+EXPORT_SYMBOL(jbd2_submit_inode_data);
+
+int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
+{
+	if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
+		!jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
+		return 0;
+	return filemap_fdatawait_range_keep_errors(
+		jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
+		jinode->i_dirty_end);
+}
+EXPORT_SYMBOL(jbd2_wait_inode_data);
 
 /*
  * Submit all the data buffers of inode associated with the transaction to
···
 {
 	struct jbd2_inode *jinode;
 	int err, ret = 0;
-	struct address_space *mapping;
 
 	spin_lock(&journal->j_list_lock);
 	list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
-		loff_t dirty_start = jinode->i_dirty_start;
-		loff_t dirty_end = jinode->i_dirty_end;
-
 		if (!(jinode->i_flags & JI_WRITE_DATA))
 			continue;
-		mapping = jinode->i_vfs_inode->i_mapping;
 		jinode->i_flags |= JI_COMMIT_RUNNING;
 		spin_unlock(&journal->j_list_lock);
-		/*
-		 * submit the inode data buffers. We use writepage
-		 * instead of writepages. Because writepages can do
-		 * block allocation  with delalloc. We need to write
-		 * only allocated blocks here.
-		 */
+		/* submit the inode data buffers. */
 		trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
-		err = journal_submit_inode_data_buffers(mapping, dirty_start,
-				dirty_end);
-		if (!ret)
-			ret = err;
+		if (journal->j_submit_inode_data_buffers) {
+			err = journal->j_submit_inode_data_buffers(jinode);
+			if (!ret)
+				ret = err;
+		}
 		spin_lock(&journal->j_list_lock);
 		J_ASSERT(jinode->i_transaction == commit_transaction);
 		jinode->i_flags &= ~JI_COMMIT_RUNNING;
···
 	}
 	spin_unlock(&journal->j_list_lock);
 	return ret;
+}
+
+int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
+{
+	struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
+
+	return filemap_fdatawait_range_keep_errors(mapping,
+						   jinode->i_dirty_start,
+						   jinode->i_dirty_end);
 }
 
 /*
···
 	/* For locking, see the comment in journal_submit_data_buffers() */
 	spin_lock(&journal->j_list_lock);
 	list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
-		loff_t dirty_start = jinode->i_dirty_start;
-		loff_t dirty_end = jinode->i_dirty_end;
-
 		if (!(jinode->i_flags & JI_WAIT_DATA))
 			continue;
 		jinode->i_flags |= JI_COMMIT_RUNNING;
 		spin_unlock(&journal->j_list_lock);
-		err = filemap_fdatawait_range_keep_errors(
-				jinode->i_vfs_inode->i_mapping, dirty_start,
-				dirty_end);
-		if (!ret)
-			ret = err;
+		/* wait for the inode data buffers writeout. */
+		if (journal->j_finish_inode_data_buffers) {
+			err = journal->j_finish_inode_data_buffers(jinode);
+			if (!ret)
+				ret = err;
+		}
 		spin_lock(&journal->j_list_lock);
 		jinode->i_flags &= ~JI_COMMIT_RUNNING;
 		smp_mb();
···
 	J_ASSERT(journal->j_running_transaction != NULL);
 	J_ASSERT(journal->j_committing_transaction == NULL);
 
+	write_lock(&journal->j_state_lock);
+	journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
+	while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
+		DEFINE_WAIT(wait);
+
+		prepare_to_wait(&journal->j_fc_wait, &wait,
+				TASK_UNINTERRUPTIBLE);
+		write_unlock(&journal->j_state_lock);
+		schedule();
+		write_lock(&journal->j_state_lock);
+		finish_wait(&journal->j_fc_wait, &wait);
+	}
+	write_unlock(&journal->j_state_lock);
+
 	commit_transaction = journal->j_running_transaction;
 
 	trace_jbd2_start_commit(journal, commit_transaction);
···
 			commit_transaction->t_tid);
 
 	write_lock(&journal->j_state_lock);
+	journal->j_fc_off = 0;
 	J_ASSERT(commit_transaction->t_state == T_RUNNING);
 	commit_transaction->t_state = T_LOCKED;
 
···
 
 	if (journal->j_commit_callback)
 		journal->j_commit_callback(journal, commit_transaction);
+	if (journal->j_fc_cleanup_callback)
+		journal->j_fc_cleanup_callback(journal, 1);
 
 	trace_jbd2_end_commit(journal, commit_transaction);
 	jbd_debug(1, "JBD2: commit %d complete, head %d\n",
 		  journal->j_commit_sequence, journal->j_tail_sequence);
 
 	write_lock(&journal->j_state_lock);
+	journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
+	journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
 	spin_lock(&journal->j_list_lock);
 	commit_transaction->t_state = T_FINISHED;
 	/* Check if the transaction can be dropped now that we are finished */
···
 	spin_unlock(&journal->j_list_lock);
 	write_unlock(&journal->j_state_lock);
 	wake_up(&journal->j_wait_done_commit);
+	wake_up(&journal->j_fc_wait);
 
 	/*
 	 * Calculate overall stats

fs/jbd2/journal.c

···
 EXPORT_SYMBOL(jbd2_journal_force_commit);
 EXPORT_SYMBOL(jbd2_journal_inode_ranged_write);
 EXPORT_SYMBOL(jbd2_journal_inode_ranged_wait);
+EXPORT_SYMBOL(jbd2_journal_submit_inode_data_buffers);
+EXPORT_SYMBOL(jbd2_journal_finish_inode_data_buffers);
 EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
 EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
 EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
···
  *
  * 1) COMMIT:  Every so often we need to commit the current state of the
  *    filesystem to disk.  The journal thread is responsible for writing
- *    all of the metadata buffers to disk.
+ *    all of the metadata buffers to disk. If a fast commit is ongoing
+ *    journal thread waits until it's done and then continues from
+ *    there on.
  *
  * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
  *    of the data in that part of the log has been rewritten elsewhere on
···
 	return err;
 }
 
+/*
+ * Start a fast commit. If there's an ongoing fast or full commit wait for
+ * it to complete. Returns 0 if a new fast commit was started. Returns -EALREADY
+ * if a fast commit is not needed, either because there's an already a commit
+ * going on or this tid has already been committed. Returns -EINVAL if no jbd2
+ * commit has yet been performed.
+ */
+int jbd2_fc_begin_commit(journal_t *journal, tid_t tid)
+{
+	/*
+	 * Fast commits only allowed if at least one full commit has
+	 * been processed.
+	 */
+	if (!journal->j_stats.ts_tid)
+		return -EINVAL;
+
+	if (tid <= journal->j_commit_sequence)
+		return -EALREADY;
+
+	write_lock(&journal->j_state_lock);
+	if (journal->j_flags & JBD2_FULL_COMMIT_ONGOING ||
+	    (journal->j_flags & JBD2_FAST_COMMIT_ONGOING)) {
+		DEFINE_WAIT(wait);
+
+		prepare_to_wait(&journal->j_fc_wait, &wait,
+				TASK_UNINTERRUPTIBLE);
+		write_unlock(&journal->j_state_lock);
+		schedule();
+		finish_wait(&journal->j_fc_wait, &wait);
+		return -EALREADY;
+	}
+	journal->j_flags |= JBD2_FAST_COMMIT_ONGOING;
+	write_unlock(&journal->j_state_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(jbd2_fc_begin_commit);
+
+/*
+ * Stop a fast commit. If fallback is set, this function starts commit of
+ * TID tid before any other fast commit can start.
+ */
+static int __jbd2_fc_end_commit(journal_t *journal, tid_t tid, bool fallback)
+{
+	if (journal->j_fc_cleanup_callback)
+		journal->j_fc_cleanup_callback(journal, 0);
+	write_lock(&journal->j_state_lock);
+	journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
+	if (fallback)
+		journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
+	write_unlock(&journal->j_state_lock);
+	wake_up(&journal->j_fc_wait);
+	if (fallback)
+		return jbd2_complete_transaction(journal, tid);
+	return 0;
+}
+
+int jbd2_fc_end_commit(journal_t *journal)
+{
+	return __jbd2_fc_end_commit(journal, 0, 0);
+}
+EXPORT_SYMBOL(jbd2_fc_end_commit);
+
+int jbd2_fc_end_commit_fallback(journal_t *journal, tid_t tid)
+{
+	return __jbd2_fc_end_commit(journal, tid, 1);
+}
+EXPORT_SYMBOL(jbd2_fc_end_commit_fallback);
+
 /* Return 1 when transaction with given tid has already committed. */
 int jbd2_transaction_committed(journal_t *journal, tid_t tid)
 {
···
 	write_unlock(&journal->j_state_lock);
 	return jbd2_journal_bmap(journal, blocknr, retp);
 }
+
+/* Map one fast commit buffer for use by the file system */
+int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
+{
+	unsigned long long pblock;
+	unsigned long blocknr;
+	int ret = 0;
+	struct buffer_head *bh;
+	int fc_off;
+
+	*bh_out = NULL;
+	write_lock(&journal->j_state_lock);
+
+	if (journal->j_fc_off + journal->j_fc_first < journal->j_fc_last) {
+		fc_off = journal->j_fc_off;
+		blocknr = journal->j_fc_first + fc_off;
+		journal->j_fc_off++;
+	} else {
+		ret = -EINVAL;
+	}
+	write_unlock(&journal->j_state_lock);
+
+	if (ret)
+		return ret;
+
+	ret = jbd2_journal_bmap(journal, blocknr, &pblock);
+	if (ret)
+		return ret;
+
+	bh = __getblk(journal->j_dev, pblock, journal->j_blocksize);
+	if (!bh)
+		return -ENOMEM;
+
+	lock_buffer(bh);
+
+	clear_buffer_uptodate(bh);
+	set_buffer_dirty(bh);
+	unlock_buffer(bh);
+	journal->j_fc_wbuf[fc_off] = bh;
+
+	*bh_out = bh;
+
+	return 0;
+}
+EXPORT_SYMBOL(jbd2_fc_get_buf);
+
+/*
+ * Wait on fast commit buffers that were allocated by jbd2_fc_get_buf
+ * for completion.
+ */
+int jbd2_fc_wait_bufs(journal_t *journal, int num_blks)
+{
+	struct buffer_head *bh;
+	int i, j_fc_off;
+
+	read_lock(&journal->j_state_lock);
+	j_fc_off = journal->j_fc_off;
+	read_unlock(&journal->j_state_lock);
+
+	/*
+	 * Wait in reverse order to minimize chances of us being woken up before
+	 * all IOs have completed
+	 */
+	for (i = j_fc_off - 1; i >= j_fc_off - num_blks; i--) {
+		bh = journal->j_fc_wbuf[i];
+		wait_on_buffer(bh);
+		put_bh(bh);
+		journal->j_fc_wbuf[i] = NULL;
+		if (unlikely(!buffer_uptodate(bh)))
+			return -EIO;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(jbd2_fc_wait_bufs);
+
+/*
+ * Wait on fast commit buffers that were allocated by jbd2_fc_get_buf
+ * for completion.
+ */
+int jbd2_fc_release_bufs(journal_t *journal)
+{
+	struct buffer_head *bh;
+	int i, j_fc_off;
+
+	read_lock(&journal->j_state_lock);
+	j_fc_off = journal->j_fc_off;
+	read_unlock(&journal->j_state_lock);
+
+	/*
+	 * Wait in reverse order to minimize chances of us being woken up before
+	 * all IOs have completed
+	 */
+	for (i = j_fc_off - 1; i >= 0; i--) {
+		bh = journal->j_fc_wbuf[i];
+		if (!bh)
+			break;
+		put_bh(bh);
+		journal->j_fc_wbuf[i] = NULL;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(jbd2_fc_release_bufs);
 
 /*
  * Conversion of logical to physical block numbers for the journal
···
 	init_waitqueue_head(&journal->j_wait_commit);
 	init_waitqueue_head(&journal->j_wait_updates);
 	init_waitqueue_head(&journal->j_wait_reserved);
+	init_waitqueue_head(&journal->j_fc_wait);
 	mutex_init(&journal->j_abort_mutex);
 	mutex_init(&journal->j_barrier);
 	mutex_init(&journal->j_checkpoint_mutex);
···
 	if (!journal->j_wbuf)
 		goto err_cleanup;
 
+	if (journal->j_fc_wbufsize > 0) {
+		journal->j_fc_wbuf = kmalloc_array(journal->j_fc_wbufsize,
+					sizeof(struct buffer_head *),
+					GFP_KERNEL);
+		if (!journal->j_fc_wbuf)
+			goto err_cleanup;
+	}
+
 	bh = getblk_unmovable(journal->j_dev, start, journal->j_blocksize);
 	if (!bh) {
 		pr_err("%s: Cannot get buffer for journal superblock\n",
···
 
 err_cleanup:
 	kfree(journal->j_wbuf);
+	kfree(journal->j_fc_wbuf);
 	jbd2_journal_destroy_revoke(journal);
 	kfree(journal);
 	return NULL;
 }
+
+int jbd2_fc_init(journal_t *journal, int num_fc_blks)
+{
+	journal->j_fc_wbufsize = num_fc_blks;
+	journal->j_fc_wbuf = kmalloc_array(journal->j_fc_wbufsize,
+				sizeof(struct buffer_head *), GFP_KERNEL);
+	if (!journal->j_fc_wbuf)
+		return -ENOMEM;
+	return 0;
+}
+EXPORT_SYMBOL(jbd2_fc_init);
 
 /* jbd2_journal_init_dev and jbd2_journal_init_inode:
  *
···
 	}
 
 	journal->j_first = first;
-	journal->j_last = last;
 
-	journal->j_head = first;
-	journal->j_tail = first;
-	journal->j_free = last - first;
+	if (jbd2_has_feature_fast_commit(journal) &&
+	    journal->j_fc_wbufsize > 0) {
+		journal->j_fc_last = last;
+		journal->j_last = last - journal->j_fc_wbufsize;
+		journal->j_fc_first = journal->j_last + 1;
+		journal->j_fc_off = 0;
+	} else {
+		journal->j_last = last;
+	}
+
+	journal->j_head = journal->j_first;
+	journal->j_tail = journal->j_first;
+	journal->j_free = journal->j_last - journal->j_first;
 
 	journal->j_tail_sequence = journal->j_transaction_sequence;
 	journal->j_commit_sequence = journal->j_transaction_sequence - 1;
···
 static void jbd2_mark_journal_empty(journal_t *journal, int write_op)
 {
 	journal_superblock_t *sb = journal->j_superblock;
+	bool had_fast_commit = false;
 
 	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
 	lock_buffer(journal->j_sb_buffer);
···
 
 	sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
 	sb->s_start    = cpu_to_be32(0);
+	if (jbd2_has_feature_fast_commit(journal)) {
+		/*
+		 * When journal is clean, no need to commit fast commit flag and
+		 * make file system incompatible with older kernels.
+		 */
+		jbd2_clear_feature_fast_commit(journal);
+		had_fast_commit = true;
+	}
 
 	jbd2_write_superblock(journal, write_op);
+
+	if (had_fast_commit)
+		jbd2_set_feature_fast_commit(journal);
 
 	/* Log is no longer empty */
 	write_lock(&journal->j_state_lock);
···
 	journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
 	journal->j_tail = be32_to_cpu(sb->s_start);
 	journal->j_first = be32_to_cpu(sb->s_first);
-	journal->j_last = be32_to_cpu(sb->s_maxlen);
 	journal->j_errno = be32_to_cpu(sb->s_errno);
+
+	if (jbd2_has_feature_fast_commit(journal) &&
+	    journal->j_fc_wbufsize > 0) {
+		journal->j_fc_last = be32_to_cpu(sb->s_maxlen);
+		journal->j_last = journal->j_fc_last - journal->j_fc_wbufsize;
+		journal->j_fc_first = journal->j_last + 1;
+		journal->j_fc_off = 0;
+	} else {
+		journal->j_last = be32_to_cpu(sb->s_maxlen);
+	}
 
 	return 0;
 }
···
 	 */
 	journal->j_flags &= ~JBD2_ABORT;
 
+	if (journal->j_fc_wbufsize > 0)
+		jbd2_journal_set_features(journal, 0, 0,
+					  JBD2_FEATURE_INCOMPAT_FAST_COMMIT);
 	/* OK, we've finished with the dynamic journal bits:
 	 * reinitialise the dynamic contents of the superblock in memory
 	 * and reset them on disk. */
···
 		jbd2_journal_destroy_revoke(journal);
 	if (journal->j_chksum_driver)
 		crypto_free_shash(journal->j_chksum_driver);
+	if (journal->j_fc_wbufsize > 0)
+		kfree(journal->j_fc_wbuf);
 	kfree(journal->j_wbuf);
 	kfree(journal);
 

fs/jbd2/recovery.c

···
 	int		nr_revoke_hits;
 };
 
-enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
 static int do_one_pass(journal_t *journal,
 				struct recovery_info *info, enum passtype pass);
 static int scan_revoke_records(journal_t *, struct buffer_head *,
···
 /* Make sure we wrap around the log correctly! */
 #define wrap(journal, var)						\
 do {									\
-	if (var >= (journal)->j_last)					\
-		var -= ((journal)->j_last - (journal)->j_first);	\
+	unsigned long _wrap_last =					\
+		jbd2_has_feature_fast_commit(journal) ?			\
+			(journal)->j_fc_last : (journal)->j_last;	\
+									\
+	if (var >= _wrap_last)						\
+		var -= (_wrap_last - (journal)->j_first);		\
 } while (0)
+
+static int fc_do_one_pass(journal_t *journal,
+			  struct recovery_info *info, enum passtype pass)
+{
+	unsigned int expected_commit_id = info->end_transaction;
+	unsigned long next_fc_block;
+	struct buffer_head *bh;
+	int err = 0;
+
+	next_fc_block = journal->j_fc_first;
+	if (!journal->j_fc_replay_callback)
+		return 0;
+
+	while (next_fc_block <= journal->j_fc_last) {
+		jbd_debug(3, "Fast commit replay: next block %ld",
+			  next_fc_block);
+		err = jread(&bh, journal, next_fc_block);
+		if (err) {
+			jbd_debug(3, "Fast commit replay: read error");
+			break;
+		}
+
+		jbd_debug(3, "Processing fast commit blk with seq %d");
+		err = journal->j_fc_replay_callback(journal, bh, pass,
+					next_fc_block - journal->j_fc_first,
+					expected_commit_id);
+		next_fc_block++;
+		if (err < 0 || err == JBD2_FC_REPLAY_STOP)
+			break;
+		err = 0;
+	}
+
+	if (err)
+		jbd_debug(3, "Fast commit replay failed, err = %d\n", err);
+
+	return err;
+}
 
 /**
  * jbd2_journal_recover - recovers a on-disk journal
···
 	__u32			crc32_sum = ~0; /* Transactional Checksums */
 	int			descr_csum_size = 0;
 	int			block_error = 0;
+	bool			need_check_commit_time = false;
+	__u64			last_trans_commit_time = 0, commit_time;
 
 	/*
 	 * First thing is to establish what we expect to find in the log
···
 				break;
 
 		jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
-			  next_commit_ID, next_log_block, journal->j_last);
+			  next_commit_ID, next_log_block,
+			  jbd2_has_feature_fast_commit(journal) ?
+			  journal->j_fc_last : journal->j_last);
 
 		/* Skip over each chunk of the transaction looking
 		 * either the next descriptor block or the final commit
···
 			if (descr_csum_size > 0 &&
 			    !jbd2_descriptor_block_csum_verify(journal,
 							       bh->b_data)) {
-				printk(KERN_ERR "JBD2: Invalid checksum "
-				       "recovering block %lu in log\n",
-				       next_log_block);
-				err = -EFSBADCRC;
-				brelse(bh);
-				goto failed;
+				/*
+				 * PASS_SCAN can see stale blocks due to lazy
+				 * journal init. Don't error out on those yet.
+				 */
+				if (pass != PASS_SCAN) {
+					pr_err("JBD2: Invalid checksum recovering block %lu in log\n",
+					       next_log_block);
+					err = -EFSBADCRC;
+					brelse(bh);
+					goto failed;
+				}
+				need_check_commit_time = true;
+				jbd_debug(1,
+					"invalid descriptor block found in %lu\n",
+					next_log_block);
 			}
 
 			/* If it is a valid descriptor block, replay it
···
 			if (pass != PASS_REPLAY) {
 				if (pass == PASS_SCAN &&
 				    jbd2_has_feature_checksum(journal) &&
+				    !need_check_commit_time &&
 				    !info->end_transaction) {
 					if (calc_chksums(journal, bh,
 							&next_log_block,
···
 			 *	 mentioned conditions. Hence assume
 			 *	 "Interrupted Commit".)
 			 */
+			commit_time = be64_to_cpu(
+				((struct commit_header *)bh->b_data)->h_commit_sec);
+			/*
+			 * If need_check_commit_time is set, it means we are in
+			 * PASS_SCAN and csum verify failed before. If
+			 * commit_time is increasing, it's the same journal,
+			 * otherwise it is stale journal block, just end this
+			 * recovery.
+			 */
+			if (need_check_commit_time) {
+				if (commit_time >= last_trans_commit_time) {
+					pr_err("JBD2: Invalid checksum found in transaction %u\n",
+					       next_commit_ID);
+					err = -EFSBADCRC;
+					brelse(bh);
+					goto failed;
+				}
+			ignore_crc_mismatch:
+				/*
+				 * It likely does not belong to same journal,
+				 * just end this recovery with success.
+				 */
+				jbd_debug(1, "JBD2: Invalid checksum ignored in transaction %u, likely stale data\n",
+					  next_commit_ID);
+				err = 0;
+				brelse(bh);
+				goto done;
+			}
 
-			/* Found an expected commit block: if checksums
-			 * are present verify them in PASS_SCAN; else not
+			/*
+			 * Found an expected commit block: if checksums
+			 * are present, verify them in PASS_SCAN; else not
 			 * much to do other than move on to the next sequence
-			 * number. */
+			 * number.
+			 */
 			if (pass == PASS_SCAN &&
 			    jbd2_has_feature_checksum(journal)) {
 				struct commit_header *cbh =
···
 			    !jbd2_commit_block_csum_verify(journal,
 							   bh->b_data)) {
 			chksum_error:
+				if (commit_time < last_trans_commit_time)
+					goto ignore_crc_mismatch;
 				info->end_transaction = next_commit_ID;
 
 				if (!jbd2_has_feature_async_commit(journal)) {
···
 					break;
 				}
 			}
+			if (pass == PASS_SCAN)
+				last_trans_commit_time = commit_time;
 			brelse(bh);
 			next_commit_ID++;
 			continue;
 
 		case JBD2_REVOKE_BLOCK:
+			/*
+			 * Check revoke block crc in pass_scan, if csum verify
+			 * failed, check commit block time later.
+			 */
+			if (pass == PASS_SCAN &&
+			    !jbd2_descriptor_block_csum_verify(journal,
+							       bh->b_data)) {
+				jbd_debug(1, "JBD2: invalid revoke block found in %lu\n",
+					  next_log_block);
+				need_check_commit_time = true;
+			}
 			/* If we aren't in the REVOKE pass, then we can
 			 * just skip over this block. */
 			if (pass != PASS_REVOKE) {
···
 				success = -EIO;
 		}
 	}
+
+	if (jbd2_has_feature_fast_commit(journal) &&  pass != PASS_REVOKE) {
+		err = fc_do_one_pass(journal, info, pass);
+		if (err)
+			success = err;
+	}
+
 	if (block_error && success == 0)
 		success = -EIO;
 	return success;
···
 	header = (jbd2_journal_revoke_header_t *) bh->b_data;
 	offset = sizeof(jbd2_journal_revoke_header_t);
 	rcount = be32_to_cpu(header->r_count);
-
-	if (!jbd2_descriptor_block_csum_verify(journal, header))
-		return -EFSBADCRC;
 
 	if (jbd2_journal_has_csum_v2or3(journal))
 		csum_size = sizeof(struct jbd2_journal_block_tail);

fs/ocfs2/journal.c

···
 		  OCFS2_JOURNAL_DIRTY_FL);
 
 	journal->j_journal = j_journal;
+	journal->j_journal->j_submit_inode_data_buffers =
+		jbd2_journal_submit_inode_data_buffers;
+	journal->j_journal->j_finish_inode_data_buffers =
+		jbd2_journal_finish_inode_data_buffers;
 	journal->j_inode = inode;
 	journal->j_bh = bh;
 

include/linux/jbd2.h

···
 #define JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT	0x00000004
 #define JBD2_FEATURE_INCOMPAT_CSUM_V2		0x00000008
 #define JBD2_FEATURE_INCOMPAT_CSUM_V3		0x00000010
+#define JBD2_FEATURE_INCOMPAT_FAST_COMMIT	0x00000020
 
 /* See "journal feature predicate functions" below */
 
···
 					JBD2_FEATURE_INCOMPAT_64BIT | \
 					JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT | \
 					JBD2_FEATURE_INCOMPAT_CSUM_V2 | \
-					JBD2_FEATURE_INCOMPAT_CSUM_V3)
+					JBD2_FEATURE_INCOMPAT_CSUM_V3 | \
+					JBD2_FEATURE_INCOMPAT_FAST_COMMIT)
 
 #ifdef __KERNEL__
 
···
 struct jbd2_revoke_table_s;
 
 /**
- * struct handle_s - The handle_s type is the concrete type associated with
- *     handle_t.
+ * struct jbd2_journal_handle - The jbd2_journal_handle type is the concrete
+ *     type associated with handle_t.
  * @h_transaction: Which compound transaction is this update a part of?
  * @h_journal: Which journal handle belongs to - used iff h_reserved set.
  * @h_rsv_handle: Handle reserved for finishing the logical operation.
···
 	struct journal_head	*t_shadow_list;
 
 	/*
-	 * List of inodes whose data we've modified in data=ordered mode.
+	 * List of inodes associated with the transaction; e.g., ext4 uses
+	 * this to track inodes in data=ordered and data=journal mode that
+	 * need special handling on transaction commit; also used by ocfs2.
 	 * [j_list_lock]
 	 */
 	struct list_head	t_inode_list;
···
 
 #define JBD2_NR_BATCH	64
 
+enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
+
+#define JBD2_FC_REPLAY_STOP	0
+#define JBD2_FC_REPLAY_CONTINUE	1
+
 /**
  * struct journal_s - The journal_s type is the concrete type associated with
  *     journal_t.
···
 	wait_queue_head_t	j_wait_reserved;
 
 	/**
+	 * @j_fc_wait:
+	 *
+	 * Wait queue to wait for completion of async fast commits.
+	 */
+	wait_queue_head_t	j_fc_wait;
+
+	/**
 	 * @j_checkpoint_mutex:
 	 *
 	 * Semaphore for locking against concurrent checkpoints.
···
 	 * [j_state_lock].
 	 */
 	unsigned long		j_last;
+
+	/**
+	 * @j_fc_first:
+	 *
+	 * The block number of the first fast commit block in the journal
+	 * [j_state_lock].
+	 */
+	unsigned long		j_fc_first;
+
+	/**
+	 * @j_fc_off:
+	 *
+	 * Number of fast commit blocks currently allocated.
+	 * [j_state_lock].
+	 */
+	unsigned long		j_fc_off;
+
+	/**
+	 * @j_fc_last:
+	 *
+	 * The block number one beyond the last fast commit block in the journal
+	 * [j_state_lock].
+	 */
+	unsigned long		j_fc_last;
 
 	/**
 	 * @j_dev: Device where we store the journal.
···
 	struct buffer_head	**j_wbuf;
 
 	/**
+	 * @j_fc_wbuf: Array of fast commit bhs for
+	 * jbd2_journal_commit_transaction.
+	 */
+	struct buffer_head	**j_fc_wbuf;
+
+	/**
 	 * @j_wbufsize:
 	 *
 	 * Size of @j_wbuf array.
 	 */
 	int			j_wbufsize;
+
+	/**
+	 * @j_fc_wbufsize:
+	 *
+	 * Size of @j_fc_wbuf array.
+	 */
+	int			j_fc_wbufsize;
 
 	/**
 	 * @j_last_sync_writer:
···
 	 */
 	void			(*j_commit_callback)(journal_t *,
 						     transaction_t *);
+
+	/**
+	 * @j_submit_inode_data_buffers:
+	 *
+	 * This function is called for all inodes associated with the
+	 * committing transaction marked with JI_WRITE_DATA flag
+	 * before we start to write out the transaction to the journal.
+	 */
+	int			(*j_submit_inode_data_buffers)
+					(struct jbd2_inode *);
+
+	/**
+	 * @j_finish_inode_data_buffers:
+	 *
+	 * This function is called for all inodes associated with the
+	 * committing transaction marked with JI_WAIT_DATA flag
+	 * after we have written the transaction to the journal
+	 * but before we write out the commit block.
+	 */
+	int			(*j_finish_inode_data_buffers)
+					(struct jbd2_inode *);
 
 	/*
 	 * Journal statistics
···
 	 */
 	struct lockdep_map	j_trans_commit_map;
 #endif
+
+	/**
+	 * @j_fc_cleanup_callback:
+	 *
+	 * Clean-up after fast commit or full commit. JBD2 calls this function
+	 * after every commit operation.
+	 */
+	void (*j_fc_cleanup_callback)(struct journal_s *journal, int);
+
+	/*
+	 * @j_fc_replay_callback:
+	 *
+	 * File-system specific function that performs replay of a fast
+	 * commit. JBD2 calls this function for each fast commit block found in
+	 * the journal. This function should return JBD2_FC_REPLAY_CONTINUE
+	 * to indicate that the block was processed correctly and more fast
+	 * commit replay should continue. Return value of JBD2_FC_REPLAY_STOP
+	 * indicates the end of replay (no more blocks remaining). A negative
+	 * return value indicates error.
+	 */
+	int (*j_fc_replay_callback)(struct journal_s *journal,
+				    struct buffer_head *bh,
+				    enum passtype pass, int off,
+				    tid_t expected_commit_id);
 };
 
 #define jbd2_might_wait_for_commit(j) \
···
 JBD2_FEATURE_INCOMPAT_FUNCS(async_commit,	ASYNC_COMMIT)
 JBD2_FEATURE_INCOMPAT_FUNCS(csum2,		CSUM_V2)
 JBD2_FEATURE_INCOMPAT_FUNCS(csum3,		CSUM_V3)
+JBD2_FEATURE_INCOMPAT_FUNCS(fast_commit,	FAST_COMMIT)
 
 /*
  * Journal flag definitions
···
 #define JBD2_ABORT_ON_SYNCDATA_ERR	0x040	/* Abort the journal on file
 						 * data write error in ordered
 						 * mode */
+#define JBD2_FAST_COMMIT_ONGOING	0x100	/* Fast commit is ongoing */
+#define JBD2_FULL_COMMIT_ONGOING	0x200	/* Full commit is ongoing */
 
 /*
  * Function declarations for the journaling transaction and buffer
···
 extern int	   jbd2_journal_inode_ranged_wait(handle_t *handle,
 			struct jbd2_inode *inode, loff_t start_byte,
 			loff_t length);
+extern int	   jbd2_journal_submit_inode_data_buffers(
+			struct jbd2_inode *jinode);
+extern int	   jbd2_journal_finish_inode_data_buffers(
+			struct jbd2_inode *jinode);
 extern int	   jbd2_journal_begin_ordered_truncate(journal_t *journal,
 				struct jbd2_inode *inode, loff_t new_size);
 extern void	   jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode);
···
 void __jbd2_log_wait_for_space(journal_t *journal);
 extern void __jbd2_journal_drop_transaction(journal_t *, transaction_t *);
 extern int jbd2_cleanup_journal_tail(journal_t *);
+
+/* Fast commit related APIs */
+int jbd2_fc_init(journal_t *journal, int num_fc_blks);
+int jbd2_fc_begin_commit(journal_t *journal, tid_t tid);
+int jbd2_fc_end_commit(journal_t *journal);
+int jbd2_fc_end_commit_fallback(journal_t *journal, tid_t tid);
+int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out);
+int jbd2_submit_inode_data(struct jbd2_inode *jinode);
+int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode);
+int jbd2_fc_wait_bufs(journal_t *journal, int num_blks);
+int jbd2_fc_release_bufs(journal_t *journal);
 
 /*
  * is_journal_abort

include/trace/events/ext4.h

···
 	{ FALLOC_FL_COLLAPSE_RANGE,	"COLLAPSE_RANGE"},	\
 	{ FALLOC_FL_ZERO_RANGE,		"ZERO_RANGE"})
 
+#define show_fc_reason(reason)						\
+	__print_symbolic(reason,					\
+		{ EXT4_FC_REASON_XATTR,		"XATTR"},		\
+		{ EXT4_FC_REASON_CROSS_RENAME,	"CROSS_RENAME"},	\
+		{ EXT4_FC_REASON_JOURNAL_FLAG_CHANGE, "JOURNAL_FLAG_CHANGE"}, \
+		{ EXT4_FC_REASON_MEM,	"NO_MEM"},			\
+		{ EXT4_FC_REASON_SWAP_BOOT,	"SWAP_BOOT"},		\
+		{ EXT4_FC_REASON_RESIZE,	"RESIZE"},		\
+		{ EXT4_FC_REASON_RENAME_DIR,	"RENAME_DIR"},		\
+		{ EXT4_FC_REASON_FALLOC_RANGE,	"FALLOC_RANGE"})
 
 TRACE_EVENT(ext4_other_inode_update_time,
 	TP_PROTO(struct inode *inode, ino_t orig_ino),
···
 );
 
 TRACE_EVENT(ext4_load_inode,
-	TP_PROTO(struct inode *inode),
+	TP_PROTO(struct super_block *sb, unsigned long ino),
 
-	TP_ARGS(inode),
+	TP_ARGS(sb, ino),
 
 	TP_STRUCT__entry(
 		__field(	dev_t,	dev		)
···
 	),
 
 	TP_fast_assign(
-		__entry->dev		= inode->i_sb->s_dev;
-		__entry->ino		= inode->i_ino;
+		__entry->dev		= sb->s_dev;
+		__entry->ino		= ino;
 	),
 
 	TP_printk("dev %d,%d ino %ld",
···
 	TP_printk("dev %d,%d group %u",
 		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->group)
 );
+
+TRACE_EVENT(ext4_fc_replay_scan,
+	TP_PROTO(struct super_block *sb, int error, int off),
+
+	TP_ARGS(sb, error, off),
+
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(int, error)
+		__field(int, off)
+	),
+
+	TP_fast_assign(
+		__entry->dev = sb->s_dev;
+		__entry->error = error;
+		__entry->off = off;
+	),
+
+	TP_printk("FC scan pass on dev %d,%d: error %d, off %d",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->error, __entry->off)
+);
+
+TRACE_EVENT(ext4_fc_replay,
+	TP_PROTO(struct super_block *sb, int tag, int ino, int priv1, int priv2),
+
+	TP_ARGS(sb, tag, ino, priv1, priv2),
+
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(int, tag)
+		__field(int, ino)
+		__field(int, priv1)
+		__field(int, priv2)
+	),
+
+	TP_fast_assign(
+		__entry->dev = sb->s_dev;
+		__entry->tag = tag;
+		__entry->ino = ino;
+		__entry->priv1 = priv1;
+		__entry->priv2 = priv2;
+	),
+
+	TP_printk("FC Replay %d,%d: tag %d, ino %d, data1 %d, data2 %d",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->tag, __entry->ino, __entry->priv1, __entry->priv2)
+);
+
+TRACE_EVENT(ext4_fc_commit_start,
+	TP_PROTO(struct super_block *sb),
+
+	TP_ARGS(sb),
+
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+	),
+
+	TP_fast_assign(
+		__entry->dev = sb->s_dev;
+	),
+
+	TP_printk("fast_commit started on dev %d,%d",
+		  MAJOR(__entry->dev), MINOR(__entry->dev))
+);
+
+TRACE_EVENT(ext4_fc_commit_stop,
+	    TP_PROTO(struct super_block *sb, int nblks, int reason),
+
+	TP_ARGS(sb, nblks, reason),
+
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(int, nblks)
+		__field(int, reason)
+		__field(int, num_fc)
+		__field(int, num_fc_ineligible)
+		__field(int, nblks_agg)
+	),
+
+	TP_fast_assign(
+		__entry->dev = sb->s_dev;
+		__entry->nblks = nblks;
+		__entry->reason = reason;
+		__entry->num_fc = EXT4_SB(sb)->s_fc_stats.fc_num_commits;
+		__entry->num_fc_ineligible =
+			EXT4_SB(sb)->s_fc_stats.fc_ineligible_commits;
+		__entry->nblks_agg = EXT4_SB(sb)->s_fc_stats.fc_numblks;
+	),
+
+	TP_printk("fc on [%d,%d] nblks %d, reason %d, fc = %d, ineligible = %d, agg_nblks %d",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->nblks, __entry->reason, __entry->num_fc,
+		  __entry->num_fc_ineligible, __entry->nblks_agg)
+);
+
+#define FC_REASON_NAME_STAT(reason)					\
+	show_fc_reason(reason),						\
+	__entry->sbi->s_fc_stats.fc_ineligible_reason_count[reason]
+
+TRACE_EVENT(ext4_fc_stats,
+	    TP_PROTO(struct super_block *sb),
+
+	    TP_ARGS(sb),
+
+	    TP_STRUCT__entry(
+		    __field(dev_t, dev)
+		    __field(struct ext4_sb_info *, sbi)
+		    __field(int, count)
+		    ),
+
+	    TP_fast_assign(
+		    __entry->dev = sb->s_dev;
+		    __entry->sbi = EXT4_SB(sb);
+		    ),
+
+	    TP_printk("dev %d:%d fc ineligible reasons:\n"
+		      "%s:%d, %s:%d, %s:%d, %s:%d, %s:%d, %s:%d, %s:%d, %s,%d; "
+		      "num_commits:%ld, ineligible: %ld, numblks: %ld",
+		      MAJOR(__entry->dev), MINOR(__entry->dev),
+		      FC_REASON_NAME_STAT(EXT4_FC_REASON_XATTR),
+		      FC_REASON_NAME_STAT(EXT4_FC_REASON_CROSS_RENAME),
+		      FC_REASON_NAME_STAT(EXT4_FC_REASON_JOURNAL_FLAG_CHANGE),
+		      FC_REASON_NAME_STAT(EXT4_FC_REASON_MEM),
+		      FC_REASON_NAME_STAT(EXT4_FC_REASON_SWAP_BOOT),
+		      FC_REASON_NAME_STAT(EXT4_FC_REASON_RESIZE),
+		      FC_REASON_NAME_STAT(EXT4_FC_REASON_RENAME_DIR),
+		      FC_REASON_NAME_STAT(EXT4_FC_REASON_FALLOC_RANGE),
+		      __entry->sbi->s_fc_stats.fc_num_commits,
+		      __entry->sbi->s_fc_stats.fc_ineligible_commits,
+		      __entry->sbi->s_fc_stats.fc_numblks)
+
+);
+
+#define DEFINE_TRACE_DENTRY_EVENT(__type)				\
+	TRACE_EVENT(ext4_fc_track_##__type,				\
+	    TP_PROTO(struct inode *inode, struct dentry *dentry, int ret), \
+									\
+	    TP_ARGS(inode, dentry, ret),				\
+									\
+	    TP_STRUCT__entry(						\
+		    __field(dev_t, dev)					\
+		    __field(int, ino)					\
+		    __field(int, error)					\
+		    ),							\
+									\
+	    TP_fast_assign(						\
+		    __entry->dev = inode->i_sb->s_dev;			\
+		    __entry->ino = inode->i_ino;			\
+		    __entry->error = ret;				\
+		    ),							\
+									\
+	    TP_printk("dev %d:%d, inode %d, error %d, fc_%s",		\
+		      MAJOR(__entry->dev), MINOR(__entry->dev),		\
+		      __entry->ino, __entry->error,			\
+		      #__type)						\
+	)
+
+DEFINE_TRACE_DENTRY_EVENT(create);
+DEFINE_TRACE_DENTRY_EVENT(link);
+DEFINE_TRACE_DENTRY_EVENT(unlink);
+
+TRACE_EVENT(ext4_fc_track_inode,
+	    TP_PROTO(struct inode *inode, int ret),
+
+	    TP_ARGS(inode, ret),
+
+	    TP_STRUCT__entry(
+		    __field(dev_t, dev)
+		    __field(int, ino)
+		    __field(int, error)
+		    ),
+
+	    TP_fast_assign(
+		    __entry->dev = inode->i_sb->s_dev;
+		    __entry->ino = inode->i_ino;
+		    __entry->error = ret;
+		    ),
+
+	    TP_printk("dev %d:%d, inode %d, error %d",
+		      MAJOR(__entry->dev), MINOR(__entry->dev),
+		      __entry->ino, __entry->error)
+	);
+
+TRACE_EVENT(ext4_fc_track_range,
+	    TP_PROTO(struct inode *inode, long start, long end, int ret),
+
+	    TP_ARGS(inode, start, end, ret),
+
+	    TP_STRUCT__entry(
+		    __field(dev_t, dev)
+		    __field(int, ino)
+		    __field(long, start)
+		    __field(long, end)
+		    __field(int, error)
+		    ),
+
+	    TP_fast_assign(
+		    __entry->dev = inode->i_sb->s_dev;
+		    __entry->ino = inode->i_ino;
+		    __entry->start = start;
+		    __entry->end = end;
+		    __entry->error = ret;
+		    ),
+
+	    TP_printk("dev %d:%d, inode %d, error %d, start %ld, end %ld",
+		      MAJOR(__entry->dev), MINOR(__entry->dev),
+		      __entry->ino, __entry->error, __entry->start,
+		      __entry->end)
+	);
 
 #endif /* _TRACE_EXT4_H */