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Subject[PATCH v2] reiserfs: Fix inode mutex - reiserfs lock misordering
Date
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.

Reported-by: Markus Gapp <markus.gapp@gmx.net>
Reported-by: Jan Kara <jack@suse.cz>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: 2.6.36.x <stable@kernel.org>
---
fs/reiserfs/ioctl.c | 7 +++----
1 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/reiserfs/ioctl.c b/fs/reiserfs/ioctl.c
index adf22b4..d2a7955 100644
--- a/fs/reiserfs/ioctl.c
+++ b/fs/reiserfs/ioctl.c
@@ -184,12 +184,11 @@ 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) {
--
1.6.2.3


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