xfs: standardize ondisk to incore conversion for rmap btrees

Create a xfs_rmap_check_irec function to detect corruption in btree
records.  Fix all xfs_rmap_btrec_to_irec callsites to call the new
helper and bubble up corruption reports.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/libxfs/xfs_rmap.c

@@ -205,6 +205,36 @@ xfs_rmap_btrec_to_irec(
 			irec);
 }
 
+/* Simple checks for rmap records. */
+xfs_failaddr_t
+xfs_rmap_check_irec(
+	struct xfs_btree_cur		*cur,
+	const struct xfs_rmap_irec	*irec)
+{
+	struct xfs_mount		*mp = cur->bc_mp;
+
+	if (irec->rm_blockcount == 0)
+		return __this_address;
+	if (irec->rm_startblock <= XFS_AGFL_BLOCK(mp)) {
+		if (irec->rm_owner != XFS_RMAP_OWN_FS)
+			return __this_address;
+		if (irec->rm_blockcount != XFS_AGFL_BLOCK(mp) + 1)
+			return __this_address;
+	} else {
+		/* check for valid extent range, including overflow */
+		if (!xfs_verify_agbext(cur->bc_ag.pag, irec->rm_startblock,
+						       irec->rm_blockcount))
+			return __this_address;
+	}
+
+	if (!(xfs_verify_ino(mp, irec->rm_owner) ||
+	      (irec->rm_owner <= XFS_RMAP_OWN_FS &&
+	       irec->rm_owner >= XFS_RMAP_OWN_MIN)))
+		return __this_address;
+
+	return NULL;
+}
+
 /*
  * Get the data from the pointed-to record.
  */
@@ -217,39 +247,24 @@ xfs_rmap_get_rec(
 	struct xfs_mount	*mp = cur->bc_mp;
 	struct xfs_perag	*pag = cur->bc_ag.pag;
 	union xfs_btree_rec	*rec;
+	xfs_failaddr_t		fa;
 	int			error;
 
 	error = xfs_btree_get_rec(cur, &rec, stat);
 	if (error || !*stat)
 		return error;
 
-	if (xfs_rmap_btrec_to_irec(rec, irec))
-		goto out_bad_rec;
-
-	if (irec->rm_blockcount == 0)
-		goto out_bad_rec;
-	if (irec->rm_startblock <= XFS_AGFL_BLOCK(mp)) {
-		if (irec->rm_owner != XFS_RMAP_OWN_FS)
-			goto out_bad_rec;
-		if (irec->rm_blockcount != XFS_AGFL_BLOCK(mp) + 1)
-			goto out_bad_rec;
-	} else {
-		/* check for valid extent range, including overflow */
-		if (!xfs_verify_agbext(pag, irec->rm_startblock,
-					    irec->rm_blockcount))
-			goto out_bad_rec;
-	}
-
-	if (!(xfs_verify_ino(mp, irec->rm_owner) ||
-	      (irec->rm_owner <= XFS_RMAP_OWN_FS &&
-	       irec->rm_owner >= XFS_RMAP_OWN_MIN)))
+	fa = xfs_rmap_btrec_to_irec(rec, irec);
+	if (!fa)
+		fa = xfs_rmap_check_irec(cur, irec);
+	if (fa)
 		goto out_bad_rec;
 
 	return 0;
 out_bad_rec:
 	xfs_warn(mp,
-		"Reverse Mapping BTree record corruption in AG %d detected!",
-		pag->pag_agno);
+		"Reverse Mapping BTree record corruption in AG %d detected at %pS!",
+		pag->pag_agno, fa);
 	xfs_warn(mp,
 		"Owner 0x%llx, flags 0x%x, start block 0x%x block count 0x%x",
 		irec->rm_owner, irec->rm_flags, irec->rm_startblock,
@@ -2321,7 +2336,8 @@ xfs_rmap_query_range_helper(
 	struct xfs_rmap_query_range_info	*query = priv;
 	struct xfs_rmap_irec			irec;
 
-	if (xfs_rmap_btrec_to_irec(rec, &irec) != NULL)
+	if (xfs_rmap_btrec_to_irec(rec, &irec) != NULL ||
+	    xfs_rmap_check_irec(cur, &irec) != NULL)
 		return -EFSCORRUPTED;
 
 	return query->fn(cur, &irec, query->priv);

fs/xfs/libxfs/xfs_rmap.h

@@ -195,6 +195,9 @@ int xfs_rmap_compare(const struct xfs_rmap_irec *a,
 union xfs_btree_rec;
 xfs_failaddr_t xfs_rmap_btrec_to_irec(const union xfs_btree_rec *rec,
 		struct xfs_rmap_irec *irec);
+xfs_failaddr_t xfs_rmap_check_irec(struct xfs_btree_cur *cur,
+		const struct xfs_rmap_irec *irec);
+
 int xfs_rmap_has_record(struct xfs_btree_cur *cur, xfs_agblock_t bno,
 		xfs_extlen_t len, bool *exists);
 int xfs_rmap_record_exists(struct xfs_btree_cur *cur, xfs_agblock_t bno,

fs/xfs/scrub/rmap.c

@@ -93,43 +93,18 @@ xchk_rmapbt_rec(
 	struct xchk_btree	*bs,
 	const union xfs_btree_rec *rec)
 {
-	struct xfs_mount	*mp = bs->cur->bc_mp;
 	struct xfs_rmap_irec	irec;
-	struct xfs_perag	*pag = bs->cur->bc_ag.pag;
 	bool			non_inode;
 	bool			is_unwritten;
 	bool			is_bmbt;
 	bool			is_attr;
 
-	if (xfs_rmap_btrec_to_irec(rec, &irec) != NULL) {
+	if (xfs_rmap_btrec_to_irec(rec, &irec) != NULL ||
+	    xfs_rmap_check_irec(bs->cur, &irec) != NULL) {
 		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 		return 0;
 	}
 
-	/* Check extent. */
-	if (irec.rm_startblock + irec.rm_blockcount <= irec.rm_startblock)
-		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
-
-	if (irec.rm_owner == XFS_RMAP_OWN_FS) {
-		/*
-		 * xfs_verify_agbno returns false for static fs metadata.
-		 * Since that only exists at the start of the AG, validate
-		 * that by hand.
-		 */
-		if (irec.rm_startblock != 0 ||
-		    irec.rm_blockcount != XFS_AGFL_BLOCK(mp) + 1)
-			xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
-	} else {
-		/*
-		 * Otherwise we must point somewhere past the static metadata
-		 * but before the end of the FS.  Run the regular check.
-		 */
-		if (!xfs_verify_agbno(pag, irec.rm_startblock) ||
-		    !xfs_verify_agbno(pag, irec.rm_startblock +
-				irec.rm_blockcount - 1))
-			xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
-	}
-
 	/* Check flags. */
 	non_inode = XFS_RMAP_NON_INODE_OWNER(irec.rm_owner);
 	is_bmbt = irec.rm_flags & XFS_RMAP_BMBT_BLOCK;
@@ -148,16 +123,6 @@ xchk_rmapbt_rec(
 	if (non_inode && (is_bmbt || is_unwritten || is_attr))
 		xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
 
-	if (!non_inode) {
-		if (!xfs_verify_ino(mp, irec.rm_owner))
-			xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
-	} else {
-		/* Non-inode owner within the magic values? */
-		if (irec.rm_owner <= XFS_RMAP_OWN_MIN ||
-		    irec.rm_owner > XFS_RMAP_OWN_FS)
-			xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
-	}
-
 	xchk_rmapbt_xref(bs->sc, &irec);
 	return 0;
 }