Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull misc vfs updates from Al Viro:
"Misc bits and pieces not fitting into anything more specific"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: delete unnecessary assignment in vfs_listxattr
Documentation: filesystems: update filesystem locking documentation
vfs: namei: use path_equal() in follow_dotdot()
fs.h: fix outdated comment about file flags
__inode_security_revalidate() never gets NULL opt_dentry
make xattr_getsecurity() static
vfat: simplify checks in vfat_lookup()
get rid of dead code in d_find_alias()
it's SB_BORN, not MS_BORN...
msdos_rmdir(): kill BS comment
remove rpc_rmdir()
fs: avoid fdput() after failed fdget() in vfs_dedupe_file_range()

Documentation/filesystems/Locking

···
 
 locking rules:
 	all may block
-		i_mutex(inode)
-lookup:		yes
-create:		yes
-link:		yes (both)
-mknod:		yes
-symlink:	yes
-mkdir:		yes
-unlink:		yes (both)
-rmdir:		yes (both)	(see below)
-rename:	yes (all)	(see below)
+		i_rwsem(inode)
+lookup:		shared
+create:		exclusive
+link:		exclusive (both)
+mknod:		exclusive
+symlink:	exclusive
+mkdir:		exclusive
+unlink:		exclusive (both)
+rmdir:		exclusive (both)(see below)
+rename:		exclusive (all)	(see below)
 readlink:	no
 get_link:	no
-setattr:	yes
+setattr:	exclusive
 permission:	no (may not block if called in rcu-walk mode)
 get_acl:	no
 getattr:	no
 listxattr:	no
 fiemap:		no
 update_time:	no
-atomic_open:	yes
+atomic_open:	exclusive
 tmpfile:	no
 
 
-	Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
-victim.
+	Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_rwsem
+	exclusive on victim.
 	cross-directory ->rename() has (per-superblock) ->s_vfs_rename_sem.
 
 See Documentation/filesystems/directory-locking for more detailed discussion
···
 
 locking rules:
 	all may block
-		i_mutex(inode)
+		i_rwsem(inode)
 list:		no
 get:		no
-set:		yes
+set:		exclusive
 
 --------------------------- super_operations ---------------------------
 prototypes:
···
 locking rules:
 	All except set_page_dirty and freepage may block
 
-			PageLocked(page)	i_mutex
+			PageLocked(page)	i_rwsem
 writepage:		yes, unlocks (see below)
 readpage:		yes, unlocks
 writepages:
 set_page_dirty		no
 readpages:
-write_begin:		locks the page		yes
-write_end:		yes, unlocks		yes
+write_begin:		locks the page		exclusive
+write_end:		yes, unlocks		exclusive
 bmap:
 invalidatepage:		yes
 releasepage:		yes
···
 	ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
 	ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
 	int (*iterate) (struct file *, struct dir_context *);
+	int (*iterate_shared) (struct file *, struct dir_context *);
 	unsigned int (*poll) (struct file *, struct poll_table_struct *);
 	long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
 	long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
···
 mutex or just to use i_size_read() instead.
 Note: this does not protect the file->f_pos against concurrent modifications
 since this is something the userspace has to take care about.
+
+->iterate() is called with i_rwsem exclusive.
+
+->iterate_shared() is called with i_rwsem at least shared.
 
 ->fasync() is responsible for maintaining the FASYNC bit in filp->f_flags.
 Most instances call fasync_helper(), which does that maintenance, so it's

fs/dcache.c

···
 }
 EXPORT_SYMBOL(dget_parent);
 
+static struct dentry * __d_find_any_alias(struct inode *inode)
+{
+	struct dentry *alias;
+
+	if (hlist_empty(&inode->i_dentry))
+		return NULL;
+	alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
+	__dget(alias);
+	return alias;
+}
+
+/**
+ * d_find_any_alias - find any alias for a given inode
+ * @inode: inode to find an alias for
+ *
+ * If any aliases exist for the given inode, take and return a
+ * reference for one of them.  If no aliases exist, return %NULL.
+ */
+struct dentry *d_find_any_alias(struct inode *inode)
+{
+	struct dentry *de;
+
+	spin_lock(&inode->i_lock);
+	de = __d_find_any_alias(inode);
+	spin_unlock(&inode->i_lock);
+	return de;
+}
+EXPORT_SYMBOL(d_find_any_alias);
+
 /**
  * d_find_alias - grab a hashed alias of inode
  * @inode: inode in question
···
  */
 static struct dentry *__d_find_alias(struct inode *inode)
 {
-	struct dentry *alias, *discon_alias;
+	struct dentry *alias;
 
-again:
-	discon_alias = NULL;
+	if (S_ISDIR(inode->i_mode))
+		return __d_find_any_alias(inode);
+
 	hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
 		spin_lock(&alias->d_lock);
- 		if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
-			if (IS_ROOT(alias) &&
-			    (alias->d_flags & DCACHE_DISCONNECTED)) {
-				discon_alias = alias;
-			} else {
-				__dget_dlock(alias);
-				spin_unlock(&alias->d_lock);
-				return alias;
-			}
-		}
-		spin_unlock(&alias->d_lock);
-	}
-	if (discon_alias) {
-		alias = discon_alias;
-		spin_lock(&alias->d_lock);
-		if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
+ 		if (!d_unhashed(alias)) {
 			__dget_dlock(alias);
 			spin_unlock(&alias->d_lock);
 			return alias;
 		}
 		spin_unlock(&alias->d_lock);
-		goto again;
 	}
 	return NULL;
 }
···
 	return res;
 }
 EXPORT_SYMBOL(d_make_root);
-
-static struct dentry * __d_find_any_alias(struct inode *inode)
-{
-	struct dentry *alias;
-
-	if (hlist_empty(&inode->i_dentry))
-		return NULL;
-	alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
-	__dget(alias);
-	return alias;
-}
-
-/**
- * d_find_any_alias - find any alias for a given inode
- * @inode: inode to find an alias for
- *
- * If any aliases exist for the given inode, take and return a
- * reference for one of them.  If no aliases exist, return %NULL.
- */
-struct dentry *d_find_any_alias(struct inode *inode)
-{
-	struct dentry *de;
-
-	spin_lock(&inode->i_lock);
-	de = __d_find_any_alias(inode);
-	spin_unlock(&inode->i_lock);
-	return de;
-}
-EXPORT_SYMBOL(d_find_any_alias);
 
 static struct dentry *__d_instantiate_anon(struct dentry *dentry,
 					   struct inode *inode,

fs/fat/namei_msdos.c

···
 	int err;
 
 	mutex_lock(&MSDOS_SB(sb)->s_lock);
-	/*
-	 * Check whether the directory is not in use, then check
-	 * whether it is empty.
-	 */
 	err = fat_dir_empty(inode);
 	if (err)
 		goto out;

fs/fat/namei_vfat.c

···
 	return fat_search_long(dir, qname->name, len, sinfo);
 }
 
-/*
- * (nfsd's) anonymous disconnected dentry?
- * NOTE: !IS_ROOT() is not anonymous (I.e. d_splice_alias() did the job).
- */
-static int vfat_d_anon_disconn(struct dentry *dentry)
-{
-	return IS_ROOT(dentry) && (dentry->d_flags & DCACHE_DISCONNECTED);
-}
-
 static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
 				  unsigned int flags)
 {
···
 	 * Checking "alias->d_parent == dentry->d_parent" to make sure
 	 * FS is not corrupted (especially double linked dir).
 	 */
-	if (alias && alias->d_parent == dentry->d_parent &&
-	    !vfat_d_anon_disconn(alias)) {
+	if (alias && alias->d_parent == dentry->d_parent) {
 		/*
 		 * This inode has non anonymous-DCACHE_DISCONNECTED
 		 * dentry. This means, the user did ->lookup() by an
···
 		 *
 		 * Switch to new one for reason of locality if possible.
 		 */
-		BUG_ON(d_unhashed(alias));
 		if (!S_ISDIR(inode->i_mode))
 			d_move(alias, dentry);
 		iput(inode);

fs/namei.c

···
 static int follow_dotdot(struct nameidata *nd)
 {
 	while(1) {
-		if (nd->path.dentry == nd->root.dentry &&
-		    nd->path.mnt == nd->root.mnt) {
+		if (path_equal(&nd->path, &nd->root))
 			break;
-		}
 		if (nd->path.dentry != nd->path.mnt->mnt_root) {
 			int ret = path_parent_directory(&nd->path);
 			if (ret)

fs/read_write.c

···
 		ret = mnt_want_write_file(dst_file);
 		if (ret) {
 			info->status = ret;
-			goto next_loop;
+			goto next_fdput;
 		}
 
 		dst_off = info->dest_offset;
···
 
 next_file:
 		mnt_drop_write_file(dst_file);
-next_loop:
+next_fdput:
 		fdput(dst_fd);
-
+next_loop:
 		if (fatal_signal_pending(current))
 			goto out;
 	}

fs/super.c

···
 static void do_thaw_all_callback(struct super_block *sb)
 {
 	down_write(&sb->s_umount);
-	if (sb->s_root && sb->s_flags & MS_BORN) {
+	if (sb->s_root && sb->s_flags & SB_BORN) {
 		emergency_thaw_bdev(sb);
 		thaw_super_locked(sb);
 	} else {

fs/xattr.c

···
 }
 EXPORT_SYMBOL_GPL(vfs_setxattr);
 
-ssize_t
+static ssize_t
 xattr_getsecurity(struct inode *inode, const char *name, void *value,
 			size_t size)
 {
···
 out_noalloc:
 	return len;
 }
-EXPORT_SYMBOL_GPL(xattr_getsecurity);
 
 /*
  * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
···
 	if (error)
 		return error;
 	if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) {
-		error = -EOPNOTSUPP;
 		error = inode->i_op->listxattr(dentry, list, size);
 	} else {
 		error = security_inode_listsecurity(inode, list, size);

include/linux/fs.h

···
 
 /*
  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
- * to O_WRONLY and O_RDWR via the strange trick in __dentry_open()
+ * to O_WRONLY and O_RDWR via the strange trick in do_dentry_open()
  */
 
 /* file is open for reading */

include/linux/sunrpc/rpc_pipe_fs.h

···
 					   struct cache_detail *);
 extern void rpc_remove_cache_dir(struct dentry *);
 
-extern int rpc_rmdir(struct dentry *dentry);
-
 struct rpc_pipe *rpc_mkpipe_data(const struct rpc_pipe_ops *ops, int flags);
 void rpc_destroy_pipe_data(struct rpc_pipe *pipe);
 extern struct dentry *rpc_mkpipe_dentry(struct dentry *, const char *, void *,

include/linux/xattr.h

···
 	size_t value_len;
 };
 
-ssize_t xattr_getsecurity(struct inode *, const char *, void *, size_t);
 ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);

net/sunrpc/rpc_pipe.c

···
 	return ret;
 }
 
-int rpc_rmdir(struct dentry *dentry)
-{
-	struct dentry *parent;
-	struct inode *dir;
-	int error;
-
-	parent = dget_parent(dentry);
-	dir = d_inode(parent);
-	inode_lock_nested(dir, I_MUTEX_PARENT);
-	error = __rpc_rmdir(dir, dentry);
-	inode_unlock(dir);
-	dput(parent);
-	return error;
-}
-EXPORT_SYMBOL_GPL(rpc_rmdir);
-
 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 {
 	int ret;

security/selinux/hooks.c

···
  * Try reloading inode security labels that have been marked as invalid.  The
  * @may_sleep parameter indicates when sleeping and thus reloading labels is
  * allowed; when set to false, returns -ECHILD when the label is
- * invalid.  The @opt_dentry parameter should be set to a dentry of the inode;
- * when no dentry is available, set it to NULL instead.
+ * invalid.  The @dentry parameter should be set to a dentry of the inode.
  */
 static int __inode_security_revalidate(struct inode *inode,
-				       struct dentry *opt_dentry,
+				       struct dentry *dentry,
 				       bool may_sleep)
 {
 	struct inode_security_struct *isec = inode->i_security;
···
 		 * @opt_dentry is NULL and no dentry for this inode can be
 		 * found; in that case, continue using the old label.
 		 */
-		inode_doinit_with_dentry(inode, opt_dentry);
+		inode_doinit_with_dentry(inode, dentry);
 	}
 	return 0;
 }