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Commit 43b96748 authored by JackieLiu's avatar JackieLiu Committed by Shaohua Li
Browse files

md/raid5-cache: adjust the write position of the empty block if no data blocks 



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.

Signed-off-by: default avatarJackieLiu <liuyun01@kylinos.cn>
Reviewed-by: default avatarZhengyuan Liu <liuzhengyuan@kylinos.cn>
Reviewed-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent f687a33e

drivers/md/raid5-cache.c

+16 −4
Original line number Diff line number Diff line
@@ -2077,7 +2077,6 @@ 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;
@@ -2137,6 +2136,8 @@ 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;

	struct stripe_head *sh;



	ctx.pos = log->last_checkpoint;

	ctx.seq = log->last_cp_seq;
@@ -2154,6 +2155,18 @@ static int r5l_recovery_log(struct r5l_log *log) 
	if (ret)

		return ret;



       pos = ctx.pos;

       ctx.seq += 10;



	if (ctx.data_only_stripes == 0) {

		log->next_checkpoint = ctx.pos;

		r5l_log_write_empty_meta_block(log, ctx.pos, ctx.seq++);

		ctx.pos = r5l_ring_add(log, ctx.pos, BLOCK_SECTORS);

	} else {

		sh = list_last_entry(&ctx.cached_list, struct stripe_head, lru);

		log->next_checkpoint = sh->log_start;

	}



	if ((ctx.data_only_stripes == 0) && (ctx.data_parity_stripes == 0))

		pr_debug("md/raid:%s: starting from clean shutdown\n",

			 mdname(mddev));
@@ -2171,10 +2184,9 @@ static int r5l_recovery_log(struct r5l_log *log) 
	}



	log->log_start = ctx.pos;

	log->next_checkpoint = ctx.pos;

	log->seq = ctx.seq;

	r5l_log_write_empty_meta_block(log, ctx.pos, ctx.seq);

	r5l_write_super(log, ctx.pos);

	log->last_checkpoint = pos;

	r5l_write_super(log, pos);

	return 0;

}