NTFS: Modify fs/ntfs/mft.c::map_extent_mft_record() to only verify the mft

      record sequence number if it is specified (i.e. not zero).
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

fs/ntfs/ChangeLog

@@ -134,6 +134,8 @@ ToDo/Notes:
 	  that resulted due to #includes and header file interdependencies.
 	- Simplify setup of i_mode in fs/ntfs/inode.c::ntfs_read_locked_inode().
 	- Add helpers fs/ntfs/layout.h::MK_MREF() and MK_LE_MREF().
+	- Modify fs/ntfs/mft.c::map_extent_mft_record() to only verify the mft
+	  record sequence number if it is specified (i.e. not zero).
 
 2.1.20 - Fix two stupid bugs introduced in 2.1.18 release.
 

fs/ntfs/mft.c

@@ -302,8 +302,8 @@ MFT_RECORD *map_extent_mft_record(ntfs_inode *base_ni, MFT_REF mref,
 		ntfs_clear_extent_inode(ni);
 		goto map_err_out;
 	}
-	/* Verify the sequence number. */
-	if (unlikely(le16_to_cpu(m->sequence_number) != seq_no)) {
+	/* Verify the sequence number if it is present. */
+	if (seq_no && (le16_to_cpu(m->sequence_number) != seq_no)) {
 		ntfs_error(base_ni->vol->sb, "Found stale extent mft "
 				"reference! Corrupt file system. Run chkdsk.");
 		destroy_ni = TRUE;