Accessing if_bytes without the ilock is racy. Move the check a little
further down into the ilock critical section.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/xfs/xfs_reflink.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 7da0e8f961d351..df632790a0a51c 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -731,12 +731,6 @@ xfs_reflink_end_cow_extent(
int nmaps;
int error;
- /* No COW extents? That's easy! */
- if (ifp->if_bytes == 0) {
- *offset_fsb = end_fsb;
- return 0;
- }
-
resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
XFS_TRANS_RESERVE, &tp);
@@ -751,6 +745,12 @@ xfs_reflink_end_cow_extent(
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);
+ /* No COW extents? That's easy! */
+ if (ifp->if_bytes == 0) {
+ *offset_fsb = end_fsb;
+ goto out_cancel;
+ }
+
error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
XFS_IEXT_REFLINK_END_COW_CNT);
if (error == -EFBIG)
--
2.39.2
