xfs: refactor data device extent validation

Refactor all the open-coded validation of non-static data device extents
into a single helper.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/libxfs/xfs_bmap.c

@@ -6242,12 +6242,8 @@ xfs_bmap_validate_extent(
 		if (!xfs_verify_rtbno(mp, endfsb))
 			return __this_address;
 	} else {
-		if (!xfs_verify_fsbno(mp, irec->br_startblock))
-			return __this_address;
-		if (!xfs_verify_fsbno(mp, endfsb))
-			return __this_address;
-		if (XFS_FSB_TO_AGNO(mp, irec->br_startblock) !=
-		    XFS_FSB_TO_AGNO(mp, endfsb))
+		if (!xfs_verify_fsbext(mp, irec->br_startblock,
+					   irec->br_blockcount))
 			return __this_address;
 	}
 	if (irec->br_state != XFS_EXT_NORM && whichfork != XFS_DATA_FORK)

fs/xfs/libxfs/xfs_types.c

@@ -61,6 +61,29 @@ xfs_verify_fsbno(
 	return xfs_verify_agbno(mp, agno, XFS_FSB_TO_AGBNO(mp, fsbno));
 }
 
+/*
+ * Verify that a data device extent is fully contained inside the filesystem,
+ * does not cross an AG boundary, and does not point at static metadata.
+ */
+bool
+xfs_verify_fsbext(
+	struct xfs_mount	*mp,
+	xfs_fsblock_t		fsbno,
+	xfs_fsblock_t		len)
+{
+	if (fsbno + len <= fsbno)
+		return false;
+
+	if (!xfs_verify_fsbno(mp, fsbno))
+		return false;
+
+	if (!xfs_verify_fsbno(mp, fsbno + len - 1))
+		return false;
+
+	return  XFS_FSB_TO_AGNO(mp, fsbno) ==
+		XFS_FSB_TO_AGNO(mp, fsbno + len - 1);
+}
+
 /* Calculate the first and last possible inode number in an AG. */
 void
 xfs_agino_range(

fs/xfs/libxfs/xfs_types.h

@@ -184,6 +184,8 @@ xfs_agblock_t xfs_ag_block_count(struct xfs_mount *mp, xfs_agnumber_t agno);
 bool xfs_verify_agbno(struct xfs_mount *mp, xfs_agnumber_t agno,
 		xfs_agblock_t agbno);
 bool xfs_verify_fsbno(struct xfs_mount *mp, xfs_fsblock_t fsbno);
+bool xfs_verify_fsbext(struct xfs_mount *mp, xfs_fsblock_t fsbno,
+		xfs_fsblock_t len);
 
 void xfs_agino_range(struct xfs_mount *mp, xfs_agnumber_t agno,
 		xfs_agino_t *first, xfs_agino_t *last);

fs/xfs/scrub/bmap.c

@@ -359,10 +359,7 @@ xchk_bmap_iextent(
 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
 				irec->br_startoff);
 	if (!info->is_rt &&
-	    (!xfs_verify_fsbno(mp, irec->br_startblock) ||
-	     !xfs_verify_fsbno(mp, end) ||
-	     XFS_FSB_TO_AGNO(mp, irec->br_startblock) !=
-				XFS_FSB_TO_AGNO(mp, end)))
+	    !xfs_verify_fsbext(mp, irec->br_startblock, irec->br_blockcount))
 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
 				irec->br_startoff);
 

fs/xfs/xfs_bmap_item.c

@@ -448,16 +448,7 @@ xfs_bui_validate(
 	if (bmap->me_startoff + bmap->me_len <= bmap->me_startoff)
 		return false;
 
-	if (bmap->me_startblock + bmap->me_len <= bmap->me_startblock)
-		return false;
-
-	if (!xfs_verify_fsbno(mp, bmap->me_startblock))
-		return false;
-
-	if (!xfs_verify_fsbno(mp, bmap->me_startblock + bmap->me_len - 1))
-		return false;
-
-	return true;
+	return xfs_verify_fsbext(mp, bmap->me_startblock, bmap->me_len);
 }
 
 /*

fs/xfs/xfs_extfree_item.c

@@ -584,16 +584,7 @@ xfs_efi_validate_ext(
 	struct xfs_mount		*mp,
 	struct xfs_extent		*extp)
 {
-	if (extp->ext_start + extp->ext_len <= extp->ext_start)
-		return false;
-
-	if (!xfs_verify_fsbno(mp, extp->ext_start))
-		return false;
-
-	if (!xfs_verify_fsbno(mp, extp->ext_start + extp->ext_len - 1))
-		return false;
-
-	return true;
+	return xfs_verify_fsbext(mp, extp->ext_start, extp->ext_len);
 }
 
 /*

fs/xfs/xfs_refcount_item.c

@@ -439,16 +439,7 @@ xfs_cui_validate_phys(
 		return false;
 	}
 
-	if (refc->pe_startblock + refc->pe_len <= refc->pe_startblock)
-		return false;
-
-	if (!xfs_verify_fsbno(mp, refc->pe_startblock))
-		return false;
-
-	if (!xfs_verify_fsbno(mp, refc->pe_startblock + refc->pe_len - 1))
-		return false;
-
-	return true;
+	return xfs_verify_fsbext(mp, refc->pe_startblock, refc->pe_len);
 }
 
 /*

fs/xfs/xfs_rmap_item.c

@@ -493,16 +493,7 @@ xfs_rui_validate_map(
 	if (rmap->me_startoff + rmap->me_len <= rmap->me_startoff)
 		return false;
 
-	if (rmap->me_startblock + rmap->me_len <= rmap->me_startblock)
-		return false;
-
-	if (!xfs_verify_fsbno(mp, rmap->me_startblock))
-		return false;
-
-	if (!xfs_verify_fsbno(mp, rmap->me_startblock + rmap->me_len - 1))
-		return false;
-
-	return true;
+	return xfs_verify_fsbext(mp, rmap->me_startblock, rmap->me_len);
 }
 
 /*