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>
This commit is contained in:
Ryusuke Konishi 2010-04-10 17:59:15 +09:00
parent 9f130263f3
commit 50614bcf29
5 changed files with 12 additions and 3 deletions

View File

@ -105,6 +105,8 @@ static void store_segsum_info(struct nilfs_segsum_info *ssi,
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 */
}
/**

View File

@ -134,7 +134,7 @@ int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
}
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 @@ int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags,
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 @@ void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
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);
}
/*

View File

@ -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 @@ struct nilfs_segsum_info {
unsigned long sumbytes;
unsigned long nfileblk;
u64 seg_seq;
__u64 cno;
time_t ctime;
sector_t next;
};
@ -135,7 +137,7 @@ void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
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 **);

View File

@ -366,7 +366,8 @@ static int nilfs_segctor_reset_segment_buffer(struct nilfs_sc_info *sci)
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;

View File

@ -377,6 +377,7 @@ union nilfs_binfo {
* @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 @@ struct nilfs_segment_summary {
__le32 ss_nfinfo;
__le32 ss_sumbytes;
__le32 ss_pad;
__le64 ss_cno;
/* array of finfo structures */
};