diff options
| author | J. Bruce Fields <bfields@redhat.com> | 2012-04-18 15:16:33 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-11-09 00:16:39 -0500 |
| commit | 375e289ea85166c5241c570940e7e7e966c63a9f (patch) | |
| tree | 406c6701e7a45a809114bfb925f474bdd20d252a /fs/inode.c | |
| parent | f27c9298fd717e1f7e63e314a7a85a3a7e77139d (diff) | |
vfs: pull ext4's double-i_mutex-locking into common code
We want to do this elsewhere as well.
Also catch any attempts to use it for directories (where this ordering
would conflict with ancestor-first directory ordering in lock_rename).
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Dave Chinner <david@fromorbit.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/inode.c')
| -rw-r--r-- | fs/inode.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/fs/inode.c b/fs/inode.c index bf7a8b3ab937..ef25afdf3906 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -943,6 +943,42 @@ void unlock_new_inode(struct inode *inode) EXPORT_SYMBOL(unlock_new_inode); /** + * lock_two_nondirectories - take two i_mutexes on non-directory objects + * @inode1: first inode to lock + * @inode2: second inode to lock + */ +void lock_two_nondirectories(struct inode *inode1, struct inode *inode2) +{ + WARN_ON_ONCE(S_ISDIR(inode1->i_mode)); + if (inode1 == inode2 || !inode2) { + mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT); + return; + } + WARN_ON_ONCE(S_ISDIR(inode2->i_mode)); + if (inode1 < inode2) { + mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT); + mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD); + } else { + mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT); + mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD); + } +} +EXPORT_SYMBOL(lock_two_nondirectories); + +/** + * unlock_two_nondirectories - release locks from lock_two_nondirectories() + * @inode1: first inode to unlock + * @inode2: second inode to unlock + */ +void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2) +{ + mutex_unlock(&inode1->i_mutex); + if (inode2 && inode2 != inode1) + mutex_unlock(&inode2->i_mutex); +} +EXPORT_SYMBOL(unlock_two_nondirectories); + +/** * iget5_locked - obtain an inode from a mounted file system * @sb: super block of file system * @hashval: hash value (usually inode number) to get |