xfs: check minimum block size for CRC filesystems

commit bec9d48d upstream.

Check the minimum block size on v5 filesystems.

[dchinner: cleaned up XFS_MIN_CRC_BLOCKSIZE check]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/xfs/libxfs/xfs_sb.c

@@ -262,6 +262,12 @@ xfs_mount_validate_sb(
 		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");
+		return -EFSCORRUPTED;
+	}
+
 	/*
 	 * Until this is fixed only page-sized or smaller data blocks work.
 	 */

fs/xfs/libxfs/xfs_types.h

@@ -75,11 +75,14 @@ typedef __int64_t	xfs_sfiloff_t;	/* signed block number in a file */
  * Minimum and maximum blocksize and sectorsize.
  * The blocksize upper limit is pretty much arbitrary.
  * The sectorsize upper limit is due to sizeof(sb_sectsize).
+ * CRC enable filesystems use 512 byte inodes, meaning 512 byte block sizes
+ * cannot be used.
  */
 #define XFS_MIN_BLOCKSIZE_LOG	9	/* i.e. 512 bytes */
 #define XFS_MAX_BLOCKSIZE_LOG	16	/* i.e. 65536 bytes */
 #define XFS_MIN_BLOCKSIZE	(1 << XFS_MIN_BLOCKSIZE_LOG)
 #define XFS_MAX_BLOCKSIZE	(1 << XFS_MAX_BLOCKSIZE_LOG)
+#define XFS_MIN_CRC_BLOCKSIZE	(1 << (XFS_MIN_BLOCKSIZE_LOG + 1))
 #define XFS_MIN_SECTORSIZE_LOG	9	/* i.e. 512 bytes */
 #define XFS_MAX_SECTORSIZE_LOG	15	/* i.e. 32768 bytes */
 #define XFS_MIN_SECTORSIZE	(1 << XFS_MIN_SECTORSIZE_LOG)