Commit f956d08a authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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  fs.h: fix outdated comment about file flags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()
parents cf626b0d eb915375

Documentation/filesystems/Locking

+24 −19
Original line number Diff line number Diff line
@@ -69,31 +69,31 @@ prototypes: 


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
@@ -111,10 +111,10 @@ prototypes: 


locking rules:

	all may block

		i_mutex(inode)

		i_rwsem(inode)

list:		no

get:		no

set:		yes

set:		exclusive



--------------------------- super_operations ---------------------------

prototypes:
@@ -217,14 +217,14 @@ 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
@@ -439,6 +439,7 @@ prototypes: 
	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);
@@ -480,6 +481,10 @@ 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

not normally something one needs to worry about.  Return values > 0 will be

fs/dcache.c

+34 −49
Original line number Diff line number Diff line
@@ -902,6 +902,35 @@ repeat: 
}

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
@@ -918,34 +947,19 @@ EXPORT_SYMBOL(dget_parent); 
 */

static struct dentry *__d_find_alias(struct inode *inode)

{

	struct dentry *alias, *discon_alias;

	struct dentry *alias;



	if (S_ISDIR(inode->i_mode))

		return __d_find_any_alias(inode);



again:

	discon_alias = NULL;

	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;

}
@@ -1927,35 +1941,6 @@ struct dentry *d_make_root(struct inode *root_inode) 
}

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,

					   bool disconnected)

fs/fat/namei_msdos.c

+0 −4
Original line number Diff line number Diff line
@@ -314,10 +314,6 @@ static int msdos_rmdir(struct inode *dir, struct dentry *dentry) 
	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

+1 −12
Original line number Diff line number Diff line
@@ -697,15 +697,6 @@ static int vfat_find(struct inode *dir, const struct qstr *qname, 
	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)

{
@@ -738,8 +729,7 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 
	 * 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
@@ -747,7 +737,6 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 
		 *

		 * 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

+1 −3
Original line number Diff line number Diff line
@@ -1438,10 +1438,8 @@ static int path_parent_directory(struct path *path) 
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)

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