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Subject[PATCH] [53/223] reiserfs: fix inode mutex - reiserfs lock misordering
Date
2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Frederic Weisbecker <fweisbec@gmail.com>
commit da905873effecd1c0166e578bc4b5006f041b18b upstream.

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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
fs/reiserfs/ioctl.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
Index: linux/fs/reiserfs/ioctl.c
===================================================================
--- linux.orig/fs/reiserfs/ioctl.c
+++ linux/fs/reiserfs/ioctl.c
@@ -186,12 +186,11 @@ int reiserfs_unpack(struct inode *inode,
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) {

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