xfs: catch bad stripe alignment configurations

When stripe alignments are invalid, data alignment algorithms in the
allocator may not work correctly. Ensure we catch superblocks with
invalid stripe alignment setups at mount time. These data alignment
mismatches are now detected at mount time like this:

XFS (loop0): SB stripe unit sanity check failed
XFS (loop0): Metadata corruption detected at xfs_sb_read_verify+0xab/0x110, xfs_sb block 0xffffffffffffffff
XFS (loop0): Unmount and run xfs_repair
XFS (loop0): First 128 bytes of corrupted metadata buffer:
0000000091c2de02: 58 46 53 42 00 00 10 00 00 00 00 00 00 00 10 00  XFSB............
0000000023bff869: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000000cdd8c893: 17 32 37 15 ff ca 46 3d 9a 17 d3 33 04 b5 f1 a2  .27...F=...3....
000000009fd2844f: 00 00 00 00 00 00 00 04 00 00 00 00 00 00 06 d0  ................
0000000088e9b0bb: 00 00 00 00 00 00 06 d1 00 00 00 00 00 00 06 d2  ................
00000000ff233a20: 00 00 00 01 00 00 10 00 00 00 00 01 00 00 00 00  ................
000000009db0ac8b: 00 00 03 60 e1 34 02 00 08 00 00 02 00 00 00 00  ...`.4..........
00000000f7022460: 00 00 00 00 00 00 00 00 0c 09 0b 01 0c 00 00 19  ................
XFS (loop0): SB validate failed with error -117.

And the mount fails.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_sb.c

@@ -278,6 +278,22 @@ xfs_mount_validate_sb(
 		return -EFSCORRUPTED;
 	}
 
+	if (sbp->sb_unit) {
+		if (!xfs_sb_version_hasdalign(sbp) ||
+		    sbp->sb_unit > sbp->sb_width ||
+		    (sbp->sb_width % sbp->sb_unit) != 0) {
+			xfs_notice(mp, "SB stripe unit sanity check failed");
+			return -EFSCORRUPTED;
+		}
+	} else if (xfs_sb_version_hasdalign(sbp)) {
+		xfs_notice(mp, "SB stripe alignment sanity check failed");
+		return -EFSCORRUPTED;
+	} else if (sbp->sb_width) {
+		xfs_notice(mp, "SB stripe width sanity check failed");
+		return -EFSCORRUPTED;
+	}
+
+
 	if (xfs_sb_version_hascrc(&mp->m_sb) &&
 	    sbp->sb_blocksize < XFS_MIN_CRC_BLOCKSIZE) {
 		xfs_notice(mp, "v5 SB sanity check failed");