1 files changed, 240 insertions, 3 deletions

diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index a42f522f52e7..2b9ed0e3af37 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -717,11 +717,248 @@ static void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
 	md_wakeup_thread(log->reclaim_thread);
 }
 
+struct r5l_recovery_ctx {
+	struct page *meta_page;		/* current meta */
+	sector_t meta_total_blocks;	/* total size of current meta and data */
+	sector_t pos;			/* recovery position */
+	u64 seq;			/* recovery position seq */
+};
+
+static int r5l_read_meta_block(struct r5l_log *log,
+			       struct r5l_recovery_ctx *ctx)
+{
+	struct page *page = ctx->meta_page;
+	struct r5l_meta_block *mb;
+	u32 crc, stored_crc;
+
+	if (!sync_page_io(log->rdev, ctx->pos, PAGE_SIZE, page, READ, false))
+		return -EIO;
+
+	mb = page_address(page);
+	stored_crc = le32_to_cpu(mb->checksum);
+	mb->checksum = 0;
+
+	if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
+	    le64_to_cpu(mb->seq) != ctx->seq ||
+	    mb->version != R5LOG_VERSION ||
+	    le64_to_cpu(mb->position) != ctx->pos)
+		return -EINVAL;
+
+	crc = crc32_le(log->uuid_checksum, (void *)mb, PAGE_SIZE);
+	if (stored_crc != crc)
+		return -EINVAL;
+
+	if (le32_to_cpu(mb->meta_size) > PAGE_SIZE)
+		return -EINVAL;
+
+	ctx->meta_total_blocks = BLOCK_SECTORS;
+
+	return 0;
+}
+
+static int r5l_recovery_flush_one_stripe(struct r5l_log *log,
+					 struct r5l_recovery_ctx *ctx,
+					 sector_t stripe_sect,
+					 int *offset, sector_t *log_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) {
+		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, READ, false);
+			sh->dev[disk_index].log_checksum =
+				le32_to_cpu(payload->checksum[0]);
+			set_bit(R5_Wantwrite, &sh->dev[disk_index].flags);
+			ctx->meta_total_blocks += BLOCK_SECTORS;
+		} else {
+			disk_index = sh->pd_idx;
+			sync_page_io(log->rdev, *log_offset, PAGE_SIZE,
+				     sh->dev[disk_index].page, READ, 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,
+					     READ, 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 += BLOCK_SECTORS * conf->max_degraded;
+		}
+
+		*log_offset = r5l_ring_add(log, *log_offset,
+					   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 = crc32_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 */
+		rdev = rcu_dereference(conf->disks[disk_index].rdev);
+		if (rdev)
+			sync_page_io(rdev, stripe_sect, PAGE_SIZE,
+				     sh->dev[disk_index].page, WRITE, false);
+		rrdev = rcu_dereference(conf->disks[disk_index].replacement);
+		if (rrdev)
+			sync_page_io(rrdev, stripe_sect, PAGE_SIZE,
+				     sh->dev[disk_index].page, WRITE, false);
+	}
+	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 log_offset;
+	sector_t stripe_sector;
+
+	mb = page_address(ctx->meta_page);
+	offset = sizeof(struct r5l_meta_block);
+	log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
+
+	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, &log_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_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 int r5l_log_write_empty_meta_block(struct r5l_log *log, sector_t pos,
+					  u64 seq)
+{
+	struct page *page;
+	struct r5l_meta_block *mb;
+	u32 crc;
+
+	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+	if (!page)
+		return -ENOMEM;
+	mb = page_address(page);
+	mb->magic = cpu_to_le32(R5LOG_MAGIC);
+	mb->version = R5LOG_VERSION;
+	mb->meta_size = cpu_to_le32(sizeof(struct r5l_meta_block));
+	mb->seq = cpu_to_le64(seq);
+	mb->position = cpu_to_le64(pos);
+	crc = crc32_le(log->uuid_checksum, (void *)mb, PAGE_SIZE);
+	mb->checksum = cpu_to_le32(crc);
+
+	if (!sync_page_io(log->rdev, pos, PAGE_SIZE, page, WRITE_FUA, false)) {
+		__free_page(page);
+		return -EIO;
+	}
+	__free_page(page);
+	return 0;
+}
+
 static int r5l_recovery_log(struct r5l_log *log)
 {
-	/* fake recovery */
-	log->seq = log->last_cp_seq + 1;
-	log->log_start = r5l_ring_add(log, log->last_checkpoint, BLOCK_SECTORS);
+	struct r5l_recovery_ctx ctx;
+
+	ctx.pos = log->last_checkpoint;
+	ctx.seq = log->last_cp_seq;
+	ctx.meta_page = alloc_page(GFP_KERNEL);
+	if (!ctx.meta_page)
+		return -ENOMEM;
+
+	r5l_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 + 1) {
+		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);
+	} else {
+		log->log_start = ctx.pos;
+		log->seq = ctx.seq;
+	}
 	return 0;
 }