diff options
| author | Arjan van de Ven <arjan@linux.intel.com> | 2006-07-03 00:25:20 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-07-03 15:27:08 -0700 |
| commit | 5c81a4197de38411fe3e27f8593fff73a5d6b868 (patch) | |
| tree | 0a7867025e08353bf9946759864beeaf0ff01ad2 | |
| parent | 59345374742ee6673c2d04b0fa8c888e881b7209 (diff) | |
[PATCH] lockdep: annotate the quota code
The quota code plays interesting games with the lock ordering; to quote Jan:
| i_mutex of inode containing quota file is acquired after all other
| quota locks. i_mutex of all other inodes is acquired before quota
| locks. Quota code makes sure (by resetting inode operations and
| setting special flag on inode) that noone tries to enter quota code
| while holding i_mutex on a quota file...
The good news is that all of this special case i_mutex grabbing happens in the
(per filesystem) low level quota write function. For this special case we
need a new I_MUTEX_* nesting level, since this just entirely outside any of
the regular VFS locking rules for i_mutex. I trust Jan on his blue eyes that
this is not ever going to deadlock; and based on that the patch below is what
it takes to inform lockdep of these very interesting new locking rules.
The new locking rule for the I_MUTEX_QUOTA nesting level is that this is the
deepest possible level of nesting for i_mutex, and that this only should be
used in quota write (and possibly read) function of filesystems. This makes
the lock ordering of the I_MUTEX_* levels:
I_MUTEX_PARENT -> I_MUTEX_CHILD -> I_MUTEX_NORMAL -> I_MUTEX_QUOTA
Has no effect on non-lockdep kernels.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Jan Kara <jack@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | fs/ext2/super.c | 2 | ||||
| -rw-r--r-- | fs/ext3/super.c | 2 | ||||
| -rw-r--r-- | fs/reiserfs/super.c | 2 | ||||
| -rw-r--r-- | fs/ufs/super.c | 2 |
4 files changed, 4 insertions, 4 deletions
diff --git a/fs/ext2/super.c b/fs/ext2/super.c index 9f43879d6d6..f2702cda977 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -1157,7 +1157,7 @@ static ssize_t ext2_quota_write(struct super_block *sb, int type, struct buffer_head tmp_bh; struct buffer_head *bh; - mutex_lock(&inode->i_mutex); + mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA); while (towrite > 0) { tocopy = sb->s_blocksize - offset < towrite ? sb->s_blocksize - offset : towrite; diff --git a/fs/ext3/super.c b/fs/ext3/super.c index f2dd7133661..813d589cc6c 100644 --- a/fs/ext3/super.c +++ b/fs/ext3/super.c @@ -2614,7 +2614,7 @@ static ssize_t ext3_quota_write(struct super_block *sb, int type, struct buffer_head *bh; handle_t *handle = journal_current_handle(); - mutex_lock(&inode->i_mutex); + mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA); while (towrite > 0) { tocopy = sb->s_blocksize - offset < towrite ? sb->s_blocksize - offset : towrite; diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c index 28eb3c88603..5567328f104 100644 --- a/fs/reiserfs/super.c +++ b/fs/reiserfs/super.c @@ -2203,7 +2203,7 @@ static ssize_t reiserfs_quota_write(struct super_block *sb, int type, size_t towrite = len; struct buffer_head tmp_bh, *bh; - mutex_lock(&inode->i_mutex); + mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA); while (towrite > 0) { tocopy = sb->s_blocksize - offset < towrite ? sb->s_blocksize - offset : towrite; diff --git a/fs/ufs/super.c b/fs/ufs/super.c index 19a99726e58..992ee0b87cc 100644 --- a/fs/ufs/super.c +++ b/fs/ufs/super.c @@ -1326,7 +1326,7 @@ static ssize_t ufs_quota_write(struct super_block *sb, int type, size_t towrite = len; struct buffer_head *bh; - mutex_lock(&inode->i_mutex); + mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA); while (towrite > 0) { tocopy = sb->s_blocksize - offset < towrite ? sb->s_blocksize - offset : towrite; |