[PATCH AUTOSEL 5.8 076/132] xfs: don't free rt blocks when we're doing a REMAP bunmapi call

Sasha Levin
2020-10-27T00:28:03Z

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

[ Upstream commit 8df0fa39bdd86ca81a8d706a6ed9d33cc65ca625 ]

When callers pass XFS_BMAPI_REMAP into xfs_bunmapi, they want the extent
to be unmapped from the given file fork without the extent being freed.
We do this for non-rt files, but we forgot to do this for realtime
files. So far this isn't a big deal since nobody makes a bunmapi call
to a rt file with the REMAP flag set, but don't leave a logic bomb.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/xfs/libxfs/xfs_bmap.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index aa784404964a0..5800773213493 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -5042,20 +5042,25 @@ xfs_bmap_del_extent_real(

flags = XFS_ILOG_CORE;
if (whichfork == XFS_DATA_FORK && XFS_IS_REALTIME_INODE(ip)) {
- xfs_fsblock_t bno;
xfs_filblks_t len;
xfs_extlen_t mod;

- bno = div_u64_rem(del->br_startblock, mp->m_sb.sb_rextsize,
- &mod);
- ASSERT(mod == 0);
len = div_u64_rem(del->br_blockcount, mp->m_sb.sb_rextsize,
&mod);
ASSERT(mod == 0);

- error = xfs_rtfree_extent(tp, bno, (xfs_extlen_t)len);
- if (error)
- goto done;
+ if (!(bflags & XFS_BMAPI_REMAP)) {
+ xfs_fsblock_t bno;
+
+ bno = div_u64_rem(del->br_startblock,
+ mp->m_sb.sb_rextsize, &mod);
+ ASSERT(mod == 0);
+
+ error = xfs_rtfree_extent(tp, bno, (xfs_extlen_t)len);
+ if (error)
+ goto done;
+ }
+
do_fx = 0;
nblks = len * mp->m_sb.sb_rextsize;
qfield = XFS_TRANS_DQ_RTBCOUNT;
--
2.25.1