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Commit 5aabf7c4 authored by Song Liu's avatar Song Liu Committed by Shaohua Li
Browse files

md/r5cache: r5cache recovery: part 2 



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: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent b4c625c6

drivers/md/raid5-cache.c

+24 −186
Original line number Diff line number Diff line
@@ -1393,156 +1393,6 @@ static int r5l_recovery_read_meta_block(struct r5l_log *log, 
	return 0;

}



static int r5l_recovery_flush_one_stripe(struct r5l_log *log,

					 struct r5l_recovery_ctx *ctx,

					 sector_t stripe_sect,

					 int *offset)

{

	struct r5conf *conf = log->rdev->mddev->private;

	struct stripe_head *sh;

	struct r5l_payload_data_parity *payload;

	int disk_index;



	sh = raid5_get_active_stripe(conf, stripe_sect, 0, 0, 0);

	while (1) {

		sector_t log_offset = r5l_ring_add(log, ctx->pos,

				ctx->meta_total_blocks);

		payload = page_address(ctx->meta_page) + *offset;



		if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) {

			raid5_compute_sector(conf,

					     le64_to_cpu(payload->location), 0,

					     &disk_index, sh);



			sync_page_io(log->rdev, log_offset, PAGE_SIZE,

				     sh->dev[disk_index].page, REQ_OP_READ, 0,

				     false);

			sh->dev[disk_index].log_checksum =

				le32_to_cpu(payload->checksum[0]);

			set_bit(R5_Wantwrite, &sh->dev[disk_index].flags);

		} else {

			disk_index = sh->pd_idx;

			sync_page_io(log->rdev, log_offset, PAGE_SIZE,

				     sh->dev[disk_index].page, REQ_OP_READ, 0,

				     false);

			sh->dev[disk_index].log_checksum =

				le32_to_cpu(payload->checksum[0]);

			set_bit(R5_Wantwrite, &sh->dev[disk_index].flags);



			if (sh->qd_idx >= 0) {

				disk_index = sh->qd_idx;

				sync_page_io(log->rdev,

					     r5l_ring_add(log, log_offset, BLOCK_SECTORS),

					     PAGE_SIZE, sh->dev[disk_index].page,

					     REQ_OP_READ, 0, false);

				sh->dev[disk_index].log_checksum =

					le32_to_cpu(payload->checksum[1]);

				set_bit(R5_Wantwrite,

					&sh->dev[disk_index].flags);

			}

		}



		ctx->meta_total_blocks += le32_to_cpu(payload->size);

		*offset += sizeof(struct r5l_payload_data_parity) +

			sizeof(__le32) *

			(le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9));

		if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_PARITY)

			break;

	}



	for (disk_index = 0; disk_index < sh->disks; disk_index++) {

		void *addr;

		u32 checksum;



		if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags))

			continue;

		addr = kmap_atomic(sh->dev[disk_index].page);

		checksum = crc32c_le(log->uuid_checksum, addr, PAGE_SIZE);

		kunmap_atomic(addr);

		if (checksum != sh->dev[disk_index].log_checksum)

			goto error;

	}



	for (disk_index = 0; disk_index < sh->disks; disk_index++) {

		struct md_rdev *rdev, *rrdev;



		if (!test_and_clear_bit(R5_Wantwrite,

					&sh->dev[disk_index].flags))

			continue;



		/* in case device is broken */

		rcu_read_lock();

		rdev = rcu_dereference(conf->disks[disk_index].rdev);

		if (rdev) {

			atomic_inc(&rdev->nr_pending);

			rcu_read_unlock();

			sync_page_io(rdev, stripe_sect, PAGE_SIZE,

				     sh->dev[disk_index].page, REQ_OP_WRITE, 0,

				     false);

			rdev_dec_pending(rdev, rdev->mddev);

			rcu_read_lock();

		}

		rrdev = rcu_dereference(conf->disks[disk_index].replacement);

		if (rrdev) {

			atomic_inc(&rrdev->nr_pending);

			rcu_read_unlock();

			sync_page_io(rrdev, stripe_sect, PAGE_SIZE,

				     sh->dev[disk_index].page, REQ_OP_WRITE, 0,

				     false);

			rdev_dec_pending(rrdev, rrdev->mddev);

			rcu_read_lock();

		}

		rcu_read_unlock();

	}

	raid5_release_stripe(sh);

	return 0;



error:

	for (disk_index = 0; disk_index < sh->disks; disk_index++)

		sh->dev[disk_index].flags = 0;

	raid5_release_stripe(sh);

	return -EINVAL;

}



static int r5l_recovery_flush_one_meta(struct r5l_log *log,

				       struct r5l_recovery_ctx *ctx)

{

	struct r5conf *conf = log->rdev->mddev->private;

	struct r5l_payload_data_parity *payload;

	struct r5l_meta_block *mb;

	int offset;

	sector_t stripe_sector;



	mb = page_address(ctx->meta_page);

	offset = sizeof(struct r5l_meta_block);



	while (offset < le32_to_cpu(mb->meta_size)) {

		int dd;



		payload = (void *)mb + offset;

		stripe_sector = raid5_compute_sector(conf,

						     le64_to_cpu(payload->location), 0, &dd, NULL);

		if (r5l_recovery_flush_one_stripe(log, ctx, stripe_sector,

						  &offset))

			return -EINVAL;

	}

	return 0;

}



/* 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,
@@ -2166,7 +2016,9 @@ 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;
@@ -2178,47 +2030,33 @@ 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;

	}



	/*

	 * This is to suppress "function defined but not used" warning.

	 * It will be removed when the two functions are used (next patch).

	 */

	if (!log) {

		r5c_recovery_flush_log(log, &ctx);

		r5c_recovery_rewrite_data_only_stripes(log, &ctx);

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

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

			 mdname(mddev));

	else {

		pr_debug("md/raid:%s: recoverying %d data-only stripes and %d data-parity stripes\n",

			 mdname(mddev), ctx.data_only_stripes,

			 ctx.data_parity_stripes);



		if (ctx.data_only_stripes > 0)

			if (r5c_recovery_rewrite_data_only_stripes(log, &ctx)) {

				pr_err("md/raid:%s: failed to rewrite stripes to journal\n",

				       mdname(mddev));

				return -EIO;

			}

	}



	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);

	return 0;

}

drivers/md/raid5.c

+2 −1
Original line number Diff line number Diff line
@@ -7100,7 +7100,8 @@ static int raid5_run(struct mddev *mddev) 


		pr_debug("md/raid:%s: using device %s as journal\n",

			 mdname(mddev), bdevname(journal_dev->bdev, b));

		r5l_init_log(conf, journal_dev);

		if (r5l_init_log(conf, journal_dev))

			goto abort;

	}



	return 0;