xfs: walk the rt reverse mapping tree when rebuilding rmap

When we're rebuilding the data device rmap, if we encounter an "rmap"
format fork, we have to walk the (realtime) rmap btree inode to build
the appropriate mappings.

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

1 files changed, 52 insertions, 1 deletions

diff --git a/fs/xfs/scrub/rmap_repair.c b/fs/xfs/scrub/rmap_repair.c
index 2a0b9e3d0fba..91c17feb4976 100644
--- a/fs/xfs/scrub/rmap_repair.c
+++ b/fs/xfs/scrub/rmap_repair.c
@@ -31,6 +31,8 @@
 #include "xfs_refcount.h"
 #include "xfs_refcount_btree.h"
 #include "xfs_ag.h"
+#include "xfs_rtrmap_btree.h"
+#include "xfs_rtgroup.h"
 #include "scrub/xfs_scrub.h"
 #include "scrub/scrub.h"
 #include "scrub/common.h"
@@ -504,7 +506,56 @@ xrep_rmap_scan_meta_btree(
 	struct xrep_rmap_ifork	*rf,
 	struct xfs_inode	*ip)
 {
-	return -EFSCORRUPTED; /* XXX placeholder */
+	struct xfs_scrub	*sc = rf->rr->sc;
+	struct xfs_rtgroup	*rtg = NULL;
+	struct xfs_btree_cur	*cur = NULL;
+	enum xfs_rtg_inodes	type;
+	int			error;
+
+	if (rf->whichfork != XFS_DATA_FORK)
+		return -EFSCORRUPTED;
+
+	switch (ip->i_metatype) {
+	case XFS_METAFILE_RTRMAP:
+		type = XFS_RTGI_RMAP;
+		break;
+	default:
+		ASSERT(0);
+		return -EFSCORRUPTED;
+	}
+
+	while ((rtg = xfs_rtgroup_next(sc->mp, rtg))) {
+		if (ip == rtg->rtg_inodes[type])
+			goto found;
+	}
+
+	/*
+	 * We should never find an rt metadata btree inode that isn't
+	 * associated with an rtgroup yet has ondisk blocks allocated to it.
+	 */
+	if (ip->i_nblocks) {
+		ASSERT(0);
+		return -EFSCORRUPTED;
+	}
+
+	return 0;
+
+found:
+	switch (ip->i_metatype) {
+	case XFS_METAFILE_RTRMAP:
+		cur = xfs_rtrmapbt_init_cursor(sc->tp, rtg);
+		break;
+	default:
+		ASSERT(0);
+		error = -EFSCORRUPTED;
+		goto out_rtg;
+	}
+
+	error = xrep_rmap_scan_iroot_btree(rf, cur);
+	xfs_btree_del_cursor(cur, error);
+out_rtg:
+	xfs_rtgroup_rele(rtg);
+	return error;
 }
 
 /* Find all the extents from a given AG in an inode fork. */