On Mon, Nov 28, 2016 at 04:19:21PM +0800, JackieLiu wrote:
> When recovery is complete, we write an empty block and record his
> position first, then make the data-only stripes rewritten done,
> the location of the empty block as the last checkpoint position
> to write into the super block. And we should update last_checkpoint
> to this empty block position.
>
> ------------------------------------------------------------------
> | old log | empty block | data only stripes | invalid log |
> ------------------------------------------------------------------
> ^ ^ ^
> | |- log->last_checkpoint |- log->log_start
> | |- log->last_cp_seq |- log->next_checkpoint
> |- log->seq=n |- log->seq=10+n
>
> At the same time, if there is no data-only stripes, this scene may appear,
> | meta1 | meta2 | meta3 |
> meta 1 is valid, meta 2 is invalid. meta 3 could be valid. so we should
> The solution is we create a new meta in meta2 with its seq == meta1's
> seq + 10 and let superblock points to meta2.
>
> Reviewed-by: Zhengyuan Liu <liuzhengyuan@xxxxxxxxxx>
> Signed-off-by: JackieLiu <liuyun01@xxxxxxxxxx>
> ---
> drivers/md/raid5-cache.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
> index 9e72180..20594f7 100644
> --- a/drivers/md/raid5-cache.c
> +++ b/drivers/md/raid5-cache.c
> @@ -2072,7 +2072,6 @@ r5c_recovery_rewrite_data_only_stripes(struct r5l_log *log,
> return -ENOMEM;
> }
>
> - ctx->seq += 10;
> list_for_each_entry_safe(sh, next, &ctx->cached_list, lru) {
> struct r5l_meta_block *mb;
> int i;
> @@ -2132,6 +2131,7 @@ static int r5l_recovery_log(struct r5l_log *log)
> struct mddev *mddev = log->rdev->mddev;
> struct r5l_recovery_ctx ctx;
> int ret;
> + sector_t pos;
>
> ctx.pos = log->last_checkpoint;
> ctx.seq = log->last_cp_seq;
> @@ -2149,6 +2149,10 @@ static int r5l_recovery_log(struct r5l_log *log)
> if (ret)
> return ret;
>
> + pos = ctx.pos;
> + r5l_log_write_empty_meta_block(log, ctx.pos, (ctx.seq += 10));
hmm, move the ctx.seq += 10 out please
> + ctx.pos = r5l_ring_add(log, ctx.pos, BLOCK_SECTORS);
> +
> if ((ctx.data_only_stripes == 0) && (ctx.data_parity_stripes == 0))
> pr_debug("md/raid:%s: starting from clean shutdown\n",
> mdname(mddev));
> @@ -2167,9 +2171,9 @@ static int r5l_recovery_log(struct r5l_log *log)
>
> log->log_start = ctx.pos;
> log->next_checkpoint = ctx.pos;
> + log->last_checkpoint = pos;
> log->seq = ctx.seq;
> - r5l_log_write_empty_meta_block(log, ctx.pos, ctx.seq);
> - r5l_write_super(log, ctx.pos);
> + r5l_write_super(log, pos);
> return 0;
> }
Applied the first 3 patches in the series. This one looks good too, but why we
always create the empty meta block? It's only required when we don't rewrite
the data. Eg, the data_only_stripes == 0.
Thanks,
Shaohua
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
