diff options
| -rw-r--r-- | drivers/md/raid5-cache.c | 602 |
1 files changed, 602 insertions, 0 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index 390be840c764..3aa7eccde620 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -1,5 +1,6 @@ /* * Copyright (C) 2015 Shaohua Li <shli@fb.com> + * Copyright (C) 2016 Song Liu <songliubraving@fb.com> * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, @@ -1354,6 +1355,9 @@ struct r5l_recovery_ctx { sector_t meta_total_blocks; /* total size of current meta and data */ sector_t pos; /* recovery position */ u64 seq; /* recovery position seq */ + int data_parity_stripes; /* number of data_parity stripes */ + int data_only_stripes; /* number of data_only stripes */ + struct list_head cached_list; }; static int r5l_recovery_read_meta_block(struct r5l_log *log, @@ -1576,6 +1580,590 @@ static int r5l_log_write_empty_meta_block(struct r5l_log *log, sector_t pos, return 0; } +/* + * r5l_recovery_load_data and r5l_recovery_load_parity uses flag R5_Wantwrite + * to mark valid (potentially not flushed) data in the journal. + * + * We already verified checksum in r5l_recovery_verify_data_checksum_for_mb, + * so there should not be any mismatch here. + */ +static void r5l_recovery_load_data(struct r5l_log *log, + struct stripe_head *sh, + struct r5l_recovery_ctx *ctx, + struct r5l_payload_data_parity *payload, + sector_t log_offset) +{ + struct mddev *mddev = log->rdev->mddev; + struct r5conf *conf = mddev->private; + int dd_idx; + + raid5_compute_sector(conf, + le64_to_cpu(payload->location), 0, + &dd_idx, sh); + sync_page_io(log->rdev, log_offset, PAGE_SIZE, + sh->dev[dd_idx].page, REQ_OP_READ, 0, false); + sh->dev[dd_idx].log_checksum = + le32_to_cpu(payload->checksum[0]); + ctx->meta_total_blocks += BLOCK_SECTORS; + + set_bit(R5_Wantwrite, &sh->dev[dd_idx].flags); + set_bit(STRIPE_R5C_CACHING, &sh->state); +} + +static void r5l_recovery_load_parity(struct r5l_log *log, + struct stripe_head *sh, + struct r5l_recovery_ctx *ctx, + struct r5l_payload_data_parity *payload, + sector_t log_offset) +{ + struct mddev *mddev = log->rdev->mddev; + struct r5conf *conf = mddev->private; + + ctx->meta_total_blocks += BLOCK_SECTORS * conf->max_degraded; + sync_page_io(log->rdev, log_offset, PAGE_SIZE, + sh->dev[sh->pd_idx].page, REQ_OP_READ, 0, false); + sh->dev[sh->pd_idx].log_checksum = + le32_to_cpu(payload->checksum[0]); + set_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags); + + if (sh->qd_idx >= 0) { + sync_page_io(log->rdev, + r5l_ring_add(log, log_offset, BLOCK_SECTORS), + PAGE_SIZE, sh->dev[sh->qd_idx].page, + REQ_OP_READ, 0, false); + sh->dev[sh->qd_idx].log_checksum = + le32_to_cpu(payload->checksum[1]); + set_bit(R5_Wantwrite, &sh->dev[sh->qd_idx].flags); + } + clear_bit(STRIPE_R5C_CACHING, &sh->state); +} + +static void r5l_recovery_reset_stripe(struct stripe_head *sh) +{ + int i; + + sh->state = 0; + sh->log_start = MaxSector; + for (i = sh->disks; i--; ) + sh->dev[i].flags = 0; +} + +static void +r5l_recovery_replay_one_stripe(struct r5conf *conf, + struct stripe_head *sh, + struct r5l_recovery_ctx *ctx) +{ + struct md_rdev *rdev, *rrdev; + int disk_index; + int data_count = 0; + + for (disk_index = 0; disk_index < sh->disks; disk_index++) { + if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags)) + continue; + if (disk_index == sh->qd_idx || disk_index == sh->pd_idx) + continue; + data_count++; + } + + /* + * stripes that only have parity must have been flushed + * before the crash that we are now recovering from, so + * there is nothing more to recovery. + */ + if (data_count == 0) + goto out; + + for (disk_index = 0; disk_index < sh->disks; disk_index++) { + if (!test_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, sh->sector, 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, sh->sector, PAGE_SIZE, + sh->dev[disk_index].page, REQ_OP_WRITE, 0, + false); + rdev_dec_pending(rrdev, rrdev->mddev); + rcu_read_lock(); + } + rcu_read_unlock(); + } + ctx->data_parity_stripes++; +out: + r5l_recovery_reset_stripe(sh); +} + +static struct stripe_head * +r5c_recovery_alloc_stripe(struct r5conf *conf, + struct list_head *recovery_list, + sector_t stripe_sect, + sector_t log_start) +{ + struct stripe_head *sh; + + sh = raid5_get_active_stripe(conf, stripe_sect, 0, 1, 0); + if (!sh) + return NULL; /* no more stripe available */ + + r5l_recovery_reset_stripe(sh); + sh->log_start = log_start; + + return sh; +} + +static struct stripe_head * +r5c_recovery_lookup_stripe(struct list_head *list, sector_t sect) +{ + struct stripe_head *sh; + + list_for_each_entry(sh, list, lru) + if (sh->sector == sect) + return sh; + return NULL; +} + +static void +r5c_recovery_drop_stripes(struct list_head *cached_stripe_list, + struct r5l_recovery_ctx *ctx) +{ + struct stripe_head *sh, *next; + + list_for_each_entry_safe(sh, next, cached_stripe_list, lru) { + r5l_recovery_reset_stripe(sh); + list_del_init(&sh->lru); + raid5_release_stripe(sh); + } +} + +static void +r5c_recovery_replay_stripes(struct list_head *cached_stripe_list, + struct r5l_recovery_ctx *ctx) +{ + struct stripe_head *sh, *next; + + list_for_each_entry_safe(sh, next, cached_stripe_list, lru) + if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) { + r5l_recovery_replay_one_stripe(sh->raid_conf, sh, ctx); + list_del_init(&sh->lru); + raid5_release_stripe(sh); + } +} + +/* if matches return 0; otherwise return -EINVAL */ +static int +r5l_recovery_verify_data_checksum(struct r5l_log *log, struct page *page, + sector_t log_offset, __le32 log_checksum) +{ + void *addr; + u32 checksum; + + sync_page_io(log->rdev, log_offset, PAGE_SIZE, + page, REQ_OP_READ, 0, false); + addr = kmap_atomic(page); + checksum = crc32c_le(log->uuid_checksum, addr, PAGE_SIZE); + kunmap_atomic(addr); + return (le32_to_cpu(log_checksum) == checksum) ? 0 : -EINVAL; +} + +/* + * before loading data to stripe cache, we need verify checksum for all data, + * if there is mismatch for any data page, we drop all data in the mata block + */ +static int +r5l_recovery_verify_data_checksum_for_mb(struct r5l_log *log, + struct r5l_recovery_ctx *ctx) +{ + struct mddev *mddev = log->rdev->mddev; + struct r5conf *conf = mddev->private; + struct r5l_meta_block *mb = page_address(ctx->meta_page); + sector_t mb_offset = sizeof(struct r5l_meta_block); + sector_t log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS); + struct page *page; + struct r5l_payload_data_parity *payload; + + page = alloc_page(GFP_KERNEL); + if (!page) + return -ENOMEM; + + while (mb_offset < le32_to_cpu(mb->meta_size)) { + payload = (void *)mb + mb_offset; + + if (payload->header.type == R5LOG_PAYLOAD_DATA) { + if (r5l_recovery_verify_data_checksum( + log, page, log_offset, + payload->checksum[0]) < 0) + goto mismatch; + } else if (payload->header.type == R5LOG_PAYLOAD_PARITY) { + if (r5l_recovery_verify_data_checksum( + log, page, log_offset, + payload->checksum[0]) < 0) + goto mismatch; + if (conf->max_degraded == 2 && /* q for RAID 6 */ + r5l_recovery_verify_data_checksum( + log, page, + r5l_ring_add(log, log_offset, + BLOCK_SECTORS), + payload->checksum[1]) < 0) + goto mismatch; + } else /* not R5LOG_PAYLOAD_DATA or R5LOG_PAYLOAD_PARITY */ + goto mismatch; + + log_offset = r5l_ring_add(log, log_offset, + le32_to_cpu(payload->size)); + + mb_offset += sizeof(struct r5l_payload_data_parity) + + sizeof(__le32) * + (le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9)); + } + + put_page(page); + return 0; + +mismatch: + put_page(page); + return -EINVAL; +} + +/* + * Analyze all data/parity pages in one meta block + * Returns: + * 0 for success + * -EINVAL for unknown playload type + * -EAGAIN for checksum mismatch of data page + * -ENOMEM for run out of memory (alloc_page failed or run out of stripes) + */ +static int +r5c_recovery_analyze_meta_block(struct r5l_log *log, + struct r5l_recovery_ctx *ctx, + struct list_head *cached_stripe_list) +{ + struct mddev *mddev = log->rdev->mddev; + struct r5conf *conf = mddev->private; + struct r5l_meta_block *mb; + struct r5l_payload_data_parity *payload; + int mb_offset; + sector_t log_offset; + sector_t stripe_sect; + struct stripe_head *sh; + int ret; + + /* + * for mismatch in data blocks, we will drop all data in this mb, but + * we will still read next mb for other data with FLUSH flag, as + * io_unit could finish out of order. + */ + ret = r5l_recovery_verify_data_checksum_for_mb(log, ctx); + if (ret == -EINVAL) + return -EAGAIN; + else if (ret) + return ret; /* -ENOMEM duo to alloc_page() failed */ + + mb = page_address(ctx->meta_page); + mb_offset = sizeof(struct r5l_meta_block); + log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS); + + while (mb_offset < le32_to_cpu(mb->meta_size)) { + int dd; + + payload = (void *)mb + mb_offset; + stripe_sect = (payload->header.type == R5LOG_PAYLOAD_DATA) ? + raid5_compute_sector( + conf, le64_to_cpu(payload->location), 0, &dd, + NULL) + : le64_to_cpu(payload->location); + + sh = r5c_recovery_lookup_stripe(cached_stripe_list, + stripe_sect); + + if (!sh) { + sh = r5c_recovery_alloc_stripe(conf, cached_stripe_list, + stripe_sect, ctx->pos); + /* + * cannot get stripe from raid5_get_active_stripe + * try replay some stripes + */ + if (!sh) { + r5c_recovery_replay_stripes( + cached_stripe_list, ctx); + sh = r5c_recovery_alloc_stripe( + conf, cached_stripe_list, + stripe_sect, ctx->pos); + } + if (!sh) { + pr_debug("md/raid:%s: Increasing stripe cache size to %d to recovery data on journal.\n", + mdname(mddev), + conf->min_nr_stripes * 2); + raid5_set_cache_size(mddev, + conf->min_nr_stripes * 2); + sh = r5c_recovery_alloc_stripe( + conf, cached_stripe_list, stripe_sect, + ctx->pos); + } + if (!sh) { + pr_err("md/raid:%s: Cannot get enough stripes due to memory pressure. Recovery failed.\n", + mdname(mddev)); + return -ENOMEM; + } + list_add_tail(&sh->lru, cached_stripe_list); + } + + if (payload->header.type == R5LOG_PAYLOAD_DATA) { + if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) { + r5l_recovery_replay_one_stripe(conf, sh, ctx); + r5l_recovery_reset_stripe(sh); + sh->log_start = ctx->pos; + list_move_tail(&sh->lru, cached_stripe_list); + } + r5l_recovery_load_data(log, sh, ctx, payload, + log_offset); + } else if (payload->header.type == R5LOG_PAYLOAD_PARITY) + r5l_recovery_load_parity(log, sh, ctx, payload, + log_offset); + else + return -EINVAL; + + log_offset = r5l_ring_add(log, log_offset, + le32_to_cpu(payload->size)); + + mb_offset += sizeof(struct r5l_payload_data_parity) + + sizeof(__le32) * + (le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9)); + } + + return 0; +} + +/* + * Load the stripe into cache. The stripe will be written out later by + * the stripe cache state machine. + */ +static void r5c_recovery_load_one_stripe(struct r5l_log *log, + struct stripe_head *sh) +{ + struct r5conf *conf = sh->raid_conf; + struct r5dev *dev; + int i; + + for (i = sh->disks; i--; ) { + dev = sh->dev + i; + if (test_and_clear_bit(R5_Wantwrite, &dev->flags)) { + set_bit(R5_InJournal, &dev->flags); + set_bit(R5_UPTODATE, &dev->flags); + } + } + set_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state); + atomic_inc(&conf->r5c_cached_partial_stripes); + list_add_tail(&sh->r5c, &log->stripe_in_journal_list); +} + +/* + * Scan through the log for all to-be-flushed data + * + * For stripes with data and parity, namely Data-Parity stripe + * (STRIPE_R5C_CACHING == 0), we simply replay all the writes. + * + * For stripes with only data, namely Data-Only stripe + * (STRIPE_R5C_CACHING == 1), we load them to stripe cache state machine. + * + * For a stripe, if we see data after parity, we should discard all previous + * data and parity for this stripe, as these data are already flushed to + * the array. + * + * At the end of the scan, we return the new journal_tail, which points to + * first data-only stripe on the journal device, or next invalid meta block. + */ +static int r5c_recovery_flush_log(struct r5l_log *log, + struct r5l_recovery_ctx *ctx) +{ + struct stripe_head *sh, *next; + int ret = 0; + + /* scan through the log */ + while (1) { + if (r5l_recovery_read_meta_block(log, ctx)) + break; + + ret = r5c_recovery_analyze_meta_block(log, ctx, + &ctx->cached_list); + /* + * -EAGAIN means mismatch in data block, in this case, we still + * try scan the next metablock + */ + if (ret && ret != -EAGAIN) + break; /* ret == -EINVAL or -ENOMEM */ + ctx->seq++; + ctx->pos = r5l_ring_add(log, ctx->pos, ctx->meta_total_blocks); + } + + if (ret == -ENOMEM) { + r5c_recovery_drop_stripes(&ctx->cached_list, ctx); + return ret; + } + + /* replay data-parity stripes */ + r5c_recovery_replay_stripes(&ctx->cached_list, ctx); + + /* load data-only stripes to stripe cache */ + list_for_each_entry_safe(sh, next, &ctx->cached_list, lru) { + WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state)); + r5c_recovery_load_one_stripe(log, sh); + list_del_init(&sh->lru); + raid5_release_stripe(sh); + ctx->data_only_stripes++; + } + + return 0; +} + +/* + * 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 + */ + +/* + * Before recovery, the log looks like the following + * + * --------------------------------------------- + * | valid log | invalid log | + * --------------------------------------------- + * ^ + * |- log->last_checkpoint + * |- log->last_cp_seq + * + * Now we scan through the log until we see invalid entry + * + * --------------------------------------------- + * | valid log | invalid log | + * --------------------------------------------- + * ^ ^ + * |- log->last_checkpoint |- ctx->pos + * |- log->last_cp_seq |- ctx->seq + * + * From this point, we need to increase seq number by 10 to avoid + * confusing next recovery. + * + * --------------------------------------------- + * | valid log | invalid log | + * --------------------------------------------- + * ^ ^ + * |- log->last_checkpoint |- ctx->pos+1 + * |- log->last_cp_seq |- ctx->seq+11 + * + * However, it is not safe to start the state machine yet, because data only + * parities are not yet secured in RAID. To save these data only parities, we + * rewrite them from seq+11. + * + * ----------------------------------------------------------------- + * | valid log | data only stripes | invalid log | + * ----------------------------------------------------------------- + * ^ ^ + * |- log->last_checkpoint |- ctx->pos+n + * |- log->last_cp_seq |- ctx->seq+10+n + * + * If failure happens again during this process, the recovery can safe start + * again from log->last_checkpoint. + * + * Once data only stripes are rewritten to journal, we move log_tail + * + * ----------------------------------------------------------------- + * | old log | data only stripes | invalid log | + * ----------------------------------------------------------------- + * ^ ^ + * |- log->last_checkpoint |- ctx->pos+n + * |- log->last_cp_seq |- ctx->seq+10+n + * + * Then we can safely start the state machine. If failure happens from this + * point on, the recovery will start from new log->last_checkpoint. + */ +static int +r5c_recovery_rewrite_data_only_stripes(struct r5l_log *log, + struct r5l_recovery_ctx *ctx) +{ + struct stripe_head *sh; + struct mddev *mddev = log->rdev->mddev; + struct page *page; + + page = alloc_page(GFP_KERNEL); + if (!page) { + pr_err("md/raid:%s: cannot allocate memory to rewrite data only stripes\n", + mdname(mddev)); + return -ENOMEM; + } + + ctx->seq += 10; + list_for_each_entry(sh, &ctx->cached_list, lru) { + struct r5l_meta_block *mb; + int i; + int offset; + sector_t write_pos; + + WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state)); + r5l_recovery_create_empty_meta_block(log, page, + ctx->pos, ctx->seq); + mb = page_address(page); + offset = le32_to_cpu(mb->meta_size); + write_pos = ctx->pos + BLOCK_SECTORS; + + for (i = sh->disks; i--; ) { + struct r5dev *dev = &sh->dev[i]; + struct r5l_payload_data_parity *payload; + void *addr; + + if (test_bit(R5_InJournal, &dev->flags)) { + payload = (void *)mb + offset; + payload->header.type = cpu_to_le16( + R5LOG_PAYLOAD_DATA); + payload->size = BLOCK_SECTORS; + payload->location = cpu_to_le64( + raid5_compute_blocknr(sh, i, 0)); + addr = kmap_atomic(dev->page); + payload->checksum[0] = cpu_to_le32( + crc32c_le(log->uuid_checksum, addr, + PAGE_SIZE)); + kunmap_atomic(addr); + sync_page_io(log->rdev, write_pos, PAGE_SIZE, + dev->page, REQ_OP_WRITE, 0, false); + write_pos = r5l_ring_add(log, write_pos, + BLOCK_SECTORS); + offset += sizeof(__le32) + + sizeof(struct r5l_payload_data_parity); + + } + } + mb->meta_size = cpu_to_le32(offset); + mb->checksum = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE); + sync_page_io(log->rdev, ctx->pos, PAGE_SIZE, page, + REQ_OP_WRITE, WRITE_FUA, false); + sh->log_start = ctx->pos; + ctx->pos = write_pos; + ctx->seq += 1; + } + __free_page(page); + return 0; +} + static int r5l_recovery_log(struct r5l_log *log) { struct r5l_recovery_ctx ctx; @@ -1583,6 +2171,10 @@ static int r5l_recovery_log(struct r5l_log *log) ctx.pos = log->last_checkpoint; ctx.seq = log->last_cp_seq; ctx.meta_page = alloc_page(GFP_KERNEL); + ctx.data_only_stripes = 0; + ctx.data_parity_stripes = 0; + INIT_LIST_HEAD(&ctx.cached_list); + if (!ctx.meta_page) return -ENOMEM; @@ -1617,6 +2209,16 @@ static int r5l_recovery_log(struct r5l_log *log) 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); + } + return 0; } |