[PATCH] xfs: fix deadlock on failure path in xfs_setattr_nonsize()

From: Alexey Khoroshilov
Date: Wed Oct 15 2014 - 17:23:20 EST


If xfs_trans_reserve() fails, xfs_setattr_nonsize() does not deallocate
the transaction and does not release "freeze" lock. That leads to the
following warning from lockdep:
[ BUG: lock held when returning to user space! ]
------------------------------------------------
fs-driver-tests/7127 is leaving the kernel with locks still held!
1 lock held by fs-driver-tests/7127:
#0: (sb_internal){.+.+.+}, at: [<ffffffffa0389a44>] xfs_trans_alloc+0x24/0x40 [xfs]

The patch adds xfs_trans_cancel() on the failure path.

Found by Linux File System Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
---
fs/xfs/xfs_iops.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 72129493e9d3..e2e785eec831 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -599,8 +599,10 @@ xfs_setattr_nonsize(

tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_NOT_SIZE);
error = xfs_trans_reserve(tp, &M_RES(mp)->tr_ichange, 0, 0);
- if (error)
+ if (error) {
+ xfs_trans_cancel(tp, 0);
goto out_dqrele;
+ }

xfs_ilock(ip, XFS_ILOCK_EXCL);

--
1.9.1

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