reiserfs: add support for mount count incrementing

The following patch adds the fields for tracking mount counts and last
fsck timestamps to the superblock.  It also increments the mount count
on every read-write mount.

Reiserfsprogs 3.6.21 added support for these fields.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/reiserfs/super.c

@@ -1280,6 +1280,8 @@ static int reiserfs_remount(struct super_block *s, int *mount_flags, char *arg)
 		REISERFS_SB(s)->s_mount_state = sb_umount_state(rs);
 		s->s_flags &= ~MS_RDONLY;
 		set_sb_umount_state(rs, REISERFS_ERROR_FS);
+		if (!old_format_only(s))
+			set_sb_mnt_count(rs, sb_mnt_count(rs) + 1);
 		/* mark_buffer_dirty (SB_BUFFER_WITH_SB (s), 1); */
 		journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));
 		REISERFS_SB(s)->s_mount_state = REISERFS_VALID_FS;
@@ -1819,7 +1821,9 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 			} else if (!silent) {
 				reiserfs_info(s, "using 3.5.x disk format\n");
 			}
-		}
+		} else
+			set_sb_mnt_count(rs, sb_mnt_count(rs) + 1);
+
 
 		journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));
 		errval = journal_end(&th, s, 1);

include/linux/reiserfs_fs.h

@@ -171,7 +171,11 @@ struct reiserfs_super_block {
 	__le32 s_flags;		/* Right now used only by inode-attributes, if enabled */
 	unsigned char s_uuid[16];	/* filesystem unique identifier */
 	unsigned char s_label[16];	/* filesystem volume label */
-	char s_unused[88];	/* zero filled by mkreiserfs and
+	__le16 s_mnt_count;		/* Count of mounts since last fsck */
+	__le16 s_max_mnt_count;		/* Maximum mounts before check */
+	__le32 s_lastcheck;		/* Timestamp of last fsck */
+	__le32 s_check_interval;	/* Interval between checks */
+	char s_unused[76];	/* zero filled by mkreiserfs and
 				 * reiserfs_convert_objectid_map_v1()
 				 * so any additions must be updated
 				 * there as well. */

include/linux/reiserfs_fs_sb.h

@@ -73,6 +73,9 @@ typedef enum {
 #define sb_version(sbp)            (le16_to_cpu((sbp)->s_v1.s_version))
 #define set_sb_version(sbp,v)      ((sbp)->s_v1.s_version = cpu_to_le16(v))
 
+#define sb_mnt_count(sbp)	   (le16_to_cpu((sbp)->s_mnt_count))
+#define set_sb_mnt_count(sbp, v)   ((sbp)->s_mnt_count = cpu_to_le16(v))
+
 #define sb_reserved_for_journal(sbp) \
               (le16_to_cpu((sbp)->s_v1.s_reserved_for_journal))
 #define set_sb_reserved_for_journal(sbp,v) \