On Thu, Nov 10, 2016 at 12:46:21PM -0800, Song Liu wrote:
> 1. In previous patch, we:
> - add new data to r5l_recovery_ctx
> - add new functions to recovery write-back cache
> The new functions are not used in this patch, so this patch does not
> change the behavior of recovery.
>
> 2. In this patchpatch, we:
> - modify main recovery procedure r5l_recovery_log() to call new
> functions
> - remove old functions
>
> Signed-off-by: Song Liu <songliubraving@xxxxxx>
> ---
> -/* copy data/parity from log to raid disks */
> -static void r5l_recovery_flush_log(struct r5l_log *log,
> - struct r5l_recovery_ctx *ctx)
> -{
> - while (1) {
> - if (r5l_recovery_read_meta_block(log, ctx))
> - return;
> - if (r5l_recovery_flush_one_meta(log, ctx))
> - return;
> - ctx->seq++;
> - ctx->pos = r5l_ring_add(log, ctx->pos, ctx->meta_total_blocks);
> - }
> -}
> -
> static void
> r5l_recovery_create_empty_meta_block(struct r5l_log *log,
> struct page *page,
> @@ -2139,7 +2001,9 @@ r5c_recovery_rewrite_data_only_stripes(struct r5l_log *log,
>
> static int r5l_recovery_log(struct r5l_log *log)
> {
> + struct mddev *mddev = log->rdev->mddev;
> struct r5l_recovery_ctx ctx;
> + int ret;
>
> ctx.pos = log->last_checkpoint;
> ctx.seq = log->last_cp_seq;
> @@ -2151,47 +2015,33 @@ static int r5l_recovery_log(struct r5l_log *log)
> if (!ctx.meta_page)
> return -ENOMEM;
>
> - r5l_recovery_flush_log(log, &ctx);
> + ret = r5c_recovery_flush_log(log, &ctx);
> __free_page(ctx.meta_page);
>
> - /*
> - * we did a recovery. Now ctx.pos points to an invalid meta block. New
> - * log will start here. but we can't let superblock point to last valid
> - * meta block. The log might looks like:
> - * | meta 1| meta 2| meta 3|
> - * meta 1 is valid, meta 2 is invalid. meta 3 could be valid. If
> - * superblock points to meta 1, we write a new valid meta 2n. if crash
> - * happens again, new recovery will start from meta 1. Since meta 2n is
> - * valid now, recovery will think meta 3 is valid, which is wrong.
> - * The solution is we create a new meta in meta2 with its seq == meta
> - * 1's seq + 10 and let superblock points to meta2. The same recovery will
> - * not think meta 3 is a valid meta, because its seq doesn't match
> - */
> - if (ctx.seq > log->last_cp_seq) {
> - int ret;
> -
> - ret = r5l_log_write_empty_meta_block(log, ctx.pos, ctx.seq + 10);
> - if (ret)
> - return ret;
> - log->seq = ctx.seq + 11;
> - log->log_start = r5l_ring_add(log, ctx.pos, BLOCK_SECTORS);
> - r5l_write_super(log, ctx.pos);
> - log->last_checkpoint = ctx.pos;
> - log->next_checkpoint = ctx.pos;
> - } else {
> - log->log_start = ctx.pos;
> - log->seq = ctx.seq;
> - }
> + if (ret)
> + return ret;
>
> - /*
> - * This is to suppress "function defined but not used" warning.
> - * It will be removed when the two functions are used (next patch).
> - */
BTW, this isn't necessary. it's ok an intermediate patch causes compile
warning, as long as it doesn't break biset.
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