nilfs2: introduce secondary super block

The former versions didn't have extra super blocks. This improves the weak point by introducing another super block at unused region in tail of the partition. This doesn't break disk format compatibility; older versions just ingore the secondary super block, and new versions just recover it if it doesn't exist. The partition created by an old mkfs may not have unused region, but in that case, the secondary super block will not be added. This doesn't make more redundant copies of the super block; it is a future work. Signed-off-by: Ryusuke Konishi <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
mrcsosa · Apr 7, 2009 · e339ad3 · e339ad3
1 parent cece552
commit e339ad3
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Showing 8 changed files with 274 additions and 175 deletions.
diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h
@@ -275,13 +275,10 @@ extern void nilfs_error(struct super_block *, const char *, const char *, ...)
 extern void nilfs_warning(struct super_block *, const char *, const char *, ...)
        __attribute__ ((format (printf, 3, 4)));
 extern struct nilfs_super_block *
-nilfs_load_super_block(struct super_block *, struct buffer_head **);
-extern struct nilfs_super_block *
-nilfs_reload_super_block(struct super_block *, struct buffer_head **, int);
+nilfs_read_super_block(struct super_block *, u64, int, struct buffer_head **);
 extern int nilfs_store_magic_and_option(struct super_block *,
 					struct nilfs_super_block *, char *);
-extern void nilfs_update_last_segment(struct nilfs_sb_info *, int);
-extern int nilfs_commit_super(struct nilfs_sb_info *);
+extern int nilfs_commit_super(struct nilfs_sb_info *, int);
 extern int nilfs_attach_checkpoint(struct nilfs_sb_info *, __u64);
 extern void nilfs_detach_checkpoint(struct nilfs_sb_info *);
 

diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c
@@ -870,7 +870,6 @@ int nilfs_search_super_root(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi,
 		if (scan_newer)
 			ri->ri_need_recovery = NILFS_RECOVERY_SR_UPDATED;
 		else {
-			nilfs->ns_prot_seq = ssi.seg_seq;
 			if (nilfs->ns_mount_state & NILFS_VALID_FS)
 				goto super_root_found;
 			scan_newer = 1;

diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
@@ -2068,7 +2068,8 @@ static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
 
 	if (update_sr) {
 		nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start,
-				       segbuf->sb_sum.seg_seq, nilfs->ns_cno);
+				       segbuf->sb_sum.seg_seq, nilfs->ns_cno++);
+		sbi->s_super->s_dirt = 1;
 
 		clear_bit(NILFS_SC_HAVE_DELTA, &sci->sc_flags);
 		clear_bit(NILFS_SC_DIRTY, &sci->sc_flags);
@@ -2224,9 +2225,6 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 
 		/* Commit segments */
 		if (has_sr) {
-			down_write(&nilfs->ns_sem);
-			nilfs_update_last_segment(sbi, 1);
-			up_write(&nilfs->ns_sem);
 			nilfs_segctor_commit_free_segments(sci);
 			nilfs_segctor_clear_metadata_dirty(sci);
 		}
@@ -2564,7 +2562,7 @@ static int nilfs_segctor_construct(struct nilfs_sc_info *sci,
 		if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
 		    nilfs_discontinued(nilfs)) {
 			down_write(&nilfs->ns_sem);
-			req->sb_err = nilfs_commit_super(sbi);
+			req->sb_err = nilfs_commit_super(sbi, 0);
 			up_write(&nilfs->ns_sem);
 		}
 	}

diff --git a/fs/nilfs2/segment.h b/fs/nilfs2/segment.h
@@ -206,8 +206,6 @@ enum {
 					   logical segment with a super root */
 #define NILFS_SC_DEFAULT_SR_FREQ    30  /* Maximum frequency of super root
 					   creation */
-#define NILFS_SC_DEFAULT_SB_FREQ    30  /* Minimum interval of periodical
-					   update of superblock (reserved) */
 
 /*
  * The default threshold amount of data, in block counts.