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reiserfs: fix inode mutex - reiserfs lock misordering

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reiserfs_unpack() locks the inode mutex with reiserfs_mutex_lock_safe()
to protect against reiserfs lock dependency.  However this protection
requires to have the reiserfs lock to be locked.

This is the case if reiserfs_unpack() is called by reiserfs_ioctl but
not from reiserfs_quota_on() when it tries to unpack tails of quota
files.

Fix the ordering of the two locks in reiserfs_unpack() to fix this
issue.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reported-by: Markus Gapp <markus.gapp@gmx.net>
Reported-by: Jan Kara <jack@suse.cz>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: <stable@kernel.org>		[2.6.36.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Frederic Weisbecker 2010-11-24 12:57:15 -08:00 committed by Linus Torvalds
parent d1d73578e0
commit da905873ef
1 changed files with 3 additions and 4 deletions
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7
fs/reiserfs/ioctl.c
View file

@ -183,12 +183,11 @@ int reiserfs_unpack(struct inode *inode, struct file *filp)
return 0;
}
/* we need to make sure nobody is changing the file size beneath
** us
*/
reiserfs_mutex_lock_safe(&inode->i_mutex, inode->i_sb);
depth = reiserfs_write_lock_once(inode->i_sb);
/* we need to make sure nobody is changing the file size beneath us */
reiserfs_mutex_lock_safe(&inode->i_mutex, inode->i_sb);
write_from = inode->i_size & (blocksize - 1);
/* if we are on a block boundary, we are already unpacked. */
if (write_from == 0) {