[PATCH] lockdep: annotate the quota code (5c81a419) · Commits · 戴 / test

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>

fs/ext2/super.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;

fs/ext3/super.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;

fs/reiserfs/super.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;

fs/ufs/super.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;

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