xfs: allow overlapping rtrmapbt records for shared data extents

Allow overlapping realtime reverse mapping records if they both describe
shared data extents and the fs supports reflink on the realtime volume.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/fs/xfs/scrub/rtrmap.c b/fs/xfs/scrub/rtrmap.c
index 3d5419682d6528d8cdbf9a6f3e808c3613e0fefd..12989fe80e8bda9c19a869cf82273d9919c54a92 100644 (file)
--- a/fs/xfs/scrub/rtrmap.c
+++ b/fs/xfs/scrub/rtrmap.c
@@ -78,6 +78,18 @@ struct xchk_rtrmap {
        struct xfs_rmap_irec    prev_rec;
 };
 
+static inline bool
+xchk_rtrmapbt_is_shareable(
+       struct xfs_scrub                *sc,
+       const struct xfs_rmap_irec      *irec)
+{
+       if (!xfs_has_rtreflink(sc->mp))
+               return false;
+       if (irec->rm_flags & XFS_RMAP_UNWRITTEN)
+               return false;
+       return true;
+}
+
 /* Flag failures for records that overlap but cannot. */
 STATIC void
 xchk_rtrmapbt_check_overlapping(
@@ -99,7 +111,10 @@ xchk_rtrmapbt_check_overlapping(
        if (pnext <= irec->rm_startblock)
                goto set_prev;
 
-       xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
+       /* Overlap is only allowed if both records are data fork mappings. */
+       if (!xchk_rtrmapbt_is_shareable(bs->sc, &cr->overlap_rec) ||
+           !xchk_rtrmapbt_is_shareable(bs->sc, irec))
+               xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 
        /* Save whichever rmap record extends furthest. */
        inext = irec->rm_startblock + irec->rm_blockcount;