[PATCH 4/8] xfs: Move ilock before transaction start in xfs_setattr_size()

Jan Kara
2012-01-20T20:34:59Z

In xfs we first take ilock and start transaction afterwards. We should obey
this order in all places because otherwise we can create the following deadlock
with filesystem freezing: One process holds ilock and blocks on s_frozen ==
SB_FREEZE_TRANS in xfs_trans_alloc(), another process has a transaction started
(thus blocking freezing) and blocks on ilock. So we have to take ilock earlier
in xfs_setattr_size().

CC: Ben Myers <bpm@sgi.com>
CC: Alex Elder <elder@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/xfs/xfs_iops.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 23ce927..3579bc8 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -850,6 +850,9 @@ xfs_setattr_size(
if (error)
goto out_unlock;

+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ lock_flags |= XFS_ILOCK_EXCL;
+
tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_SIZE);
error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
XFS_TRANS_PERM_LOG_RES,
@@ -860,9 +863,6 @@ xfs_setattr_size(
truncate_setsize(inode, iattr->ia_size);

commit_flags = XFS_TRANS_RELEASE_LOG_RES;
- lock_flags |= XFS_ILOCK_EXCL;
-
- xfs_ilock(ip, XFS_ILOCK_EXCL);

xfs_trans_ijoin(tp, ip, 0);

--
1.7.1