From: Darrick J. Wong <djwong@kernel.org>
Date: Mon, 23 Sep 2024 20:42:44 +0000 (-0700)
Subject: xfs: allow overlapping rtrmapbt records for shared data extents
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=547f4f08ba43a2e0733d351da9cb32bd27ea5d23;p=users%2Fhch%2Fxfs.git

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>
---

diff --git a/fs/xfs/scrub/rtrmap.c b/fs/xfs/scrub/rtrmap.c
index 6add6378289d..dc464749fbe3 100644
--- a/fs/xfs/scrub/rtrmap.c
+++ b/fs/xfs/scrub/rtrmap.c
@@ -79,6 +79,18 @@ 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(
@@ -100,7 +112,10 @@ 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;