[PATCH AUTOSEL 4.14 02/21] xfs: fix partially uninitialized structure in xfs_reflink_remap_extent

Sasha Levin
2020-04-24T12:28:12Z

From: "Darrick J. Wong" <darrick.wong@oracle.com>

[ Upstream commit c142932c29e533ee892f87b44d8abc5719edceec ]

In the reflink extent remap function, it turns out that uirec (the block
mapping corresponding only to the part of the passed-in mapping that got
unmapped) was not fully initialized. Specifically, br_state was not
being copied from the passed-in struct to the uirec. This could lead to
unpredictable results such as the reflinked mapping being marked
unwritten in the destination file.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/xfs/xfs_reflink.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 37e603bf15913..db7f9fdd20a30 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1125,6 +1125,7 @@ xfs_reflink_remap_extent(
uirec.br_startblock = irec->br_startblock + rlen;
uirec.br_startoff = irec->br_startoff + rlen;
uirec.br_blockcount = unmap_len - rlen;
+ uirec.br_state = irec->br_state;
unmap_len = rlen;

/* If this isn't a real mapping, we're done. */
--
2.20.1