From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
commit 4c1a67bd3606540b9b42caff34a1d5cd94b1cf65 upstream.
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@xxxxxxxxxx>
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_bmap.c | 9 +++++++++
fs/xfs/xfs_reflink.c | 2 +-
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index b79719a87638..73571fb4dfed 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -6639,6 +6639,15 @@ xfs_bmap_finish_one(
bmap.br_blockcount = *blockcount;
bmap.br_state = state;
+ /*
+ * 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),
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 29a75ecb2425..350fc64441b1 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -333,7 +333,7 @@ xfs_reflink_convert_cow_extent(
struct xfs_defer_ops *dfops)
{
struct xfs_bmbt_irec irec = *imap;
- xfs_fsblock_t first_block;
+ xfs_fsblock_t first_block = NULLFSBLOCK;
int nimaps = 1;
if (imap->br_state == XFS_EXT_NORM)
--
2.14.1
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