xfs: set firstfsb to NULLFSBLOCK before feeding it to _bmapi_write
We must initialize the firstfsb parameter to _bmapi_write so that it
doesn't incorrectly treat stack garbage as a restriction on which AGs
it can search for free space.
Fixes-coverity-id: 1402025
Fixes-coverity-id: 1415167
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 0a98807..ee118ce 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -6499,6 +6499,15 @@ xfs_bmap_finish_one(
xfs_fsblock_t firstfsb;
int error = 0;
+ /*
+ * firstfsb is tied to the transaction lifetime and is used to
+ * ensure correct AG locking order and schedule work item
+ * continuations. XFS_BUI_MAX_FAST_EXTENTS (== 1) restricts us
+ * to only making one bmap call per transaction, so it should
+ * be safe to have it as a local variable here.
+ */
+ firstfsb = NULLFSBLOCK;
+
trace_xfs_bmap_deferred(tp->t_mountp,
XFS_FSB_TO_AGNO(tp->t_mountp, startblock), type,
XFS_FSB_TO_AGBNO(tp->t_mountp, startblock),