xfs: don't free rt blocks when we're doing a REMAP bunmapi call

BugLink: https://bugs.launchpad.net/bugs/1904450
[ 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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: William Breathitt Gray <william.gray@canonical.com>

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index f8db3fe616df9e4767a6aa92637ed52309d45cad..c114d24be61938ecba2336dd518ea325363883e9 100644 (file)
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4985,20 +4985,25 @@ 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;