nilfs2: insert checkpoint number in segment summary header
This adds a field to record the latest checkpoint number in the
nilfs_segment_summary structure. This will help to recover the latest
checkpoint number from logs on disk. This field is intended for
crucial cases in which super blocks have lost pointer to the latest
log.
Even though this will change the disk format, both backward and
forward compatibility is preserved by a size field prepared in the
segment summary header.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c
index ba43146..bae2a51 100644
--- a/fs/nilfs2/recovery.c
+++ b/fs/nilfs2/recovery.c
@@ -105,6 +105,8 @@
ssi->nsumblk = DIV_ROUND_UP(ssi->sumbytes, blocksize);
ssi->nfileblk = ssi->nblocks - ssi->nsumblk - !!NILFS_SEG_HAS_SR(ssi);
+
+ /* need to verify ->ss_bytes field if read ->ss_cno */
}
/**
diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index 9f83bc0..2e6a272 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -134,7 +134,7 @@
}
int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags,
- time_t ctime)
+ time_t ctime, __u64 cno)
{
int err;
@@ -147,6 +147,7 @@
segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
segbuf->sb_sum.ctime = ctime;
+ segbuf->sb_sum.cno = cno;
return 0;
}
@@ -172,6 +173,7 @@
raw_sum->ss_nfinfo = cpu_to_le32(segbuf->sb_sum.nfinfo);
raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
raw_sum->ss_pad = 0;
+ raw_sum->ss_cno = cpu_to_le64(segbuf->sb_sum.cno);
}
/*
diff --git a/fs/nilfs2/segbuf.h b/fs/nilfs2/segbuf.h
index e21497f..fdf1c3b 100644
--- a/fs/nilfs2/segbuf.h
+++ b/fs/nilfs2/segbuf.h
@@ -37,6 +37,7 @@
* @sumbytes: Byte count of segment summary
* @nfileblk: Total number of file blocks
* @seg_seq: Segment sequence number
+ * @cno: Checkpoint number
* @ctime: Creation time
* @next: Block number of the next full segment
*/
@@ -48,6 +49,7 @@
unsigned long sumbytes;
unsigned long nfileblk;
u64 seg_seq;
+ __u64 cno;
time_t ctime;
sector_t next;
};
@@ -135,7 +137,7 @@
struct nilfs_segment_buffer *prev);
void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
struct the_nilfs *);
-int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned, time_t);
+int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned, time_t, __u64);
int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
struct buffer_head **);
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index a17bfa1..9f50fde 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -366,7 +366,8 @@
if (nilfs_doing_gc())
flags = NILFS_SS_GC;
- err = nilfs_segbuf_reset(segbuf, flags, sci->sc_seg_ctime);
+ err = nilfs_segbuf_reset(segbuf, flags, sci->sc_seg_ctime,
+ sci->sc_sbi->s_nilfs->ns_cno);
if (unlikely(err))
return err;
diff --git a/include/linux/nilfs2_fs.h b/include/linux/nilfs2_fs.h
index f960e1d..6505c00 100644
--- a/include/linux/nilfs2_fs.h
+++ b/include/linux/nilfs2_fs.h
@@ -377,6 +377,7 @@
* @ss_nfinfo: number of finfo structures
* @ss_sumbytes: total size of segment summary in bytes
* @ss_pad: padding
+ * @ss_cno: checkpoint number
*/
struct nilfs_segment_summary {
__le32 ss_datasum;
@@ -391,6 +392,7 @@
__le32 ss_nfinfo;
__le32 ss_sumbytes;
__le32 ss_pad;
+ __le64 ss_cno;
/* array of finfo structures */
};