diff options
Diffstat (limited to 'drivers/md/raid5-cache.c')
| -rw-r--r-- | drivers/md/raid5-cache.c | 1191 |
1 files changed, 1191 insertions, 0 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c new file mode 100644 index 000000000..b887e04d7 --- /dev/null +++ b/drivers/md/raid5-cache.c @@ -0,0 +1,1191 @@ +/* + * Copyright (C) 2015 Shaohua Li <shli@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, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + */ +#include <linux/kernel.h> +#include <linux/wait.h> +#include <linux/blkdev.h> +#include <linux/slab.h> +#include <linux/raid/md_p.h> +#include <linux/crc32c.h> +#include <linux/random.h> +#include "md.h" +#include "raid5.h" + +/* + * metadata/data stored in disk with 4k size unit (a block) regardless + * underneath hardware sector size. only works with PAGE_SIZE == 4096 + */ +#define BLOCK_SECTORS (8) + +/* + * reclaim runs every 1/4 disk size or 10G reclaimable space. This can prevent + * recovery scans a very long log + */ +#define RECLAIM_MAX_FREE_SPACE (10 * 1024 * 1024 * 2) /* sector */ +#define RECLAIM_MAX_FREE_SPACE_SHIFT (2) + +struct r5l_log { + struct md_rdev *rdev; + + u32 uuid_checksum; + + sector_t device_size; /* log device size, round to + * BLOCK_SECTORS */ + sector_t max_free_space; /* reclaim run if free space is at + * this size */ + + sector_t last_checkpoint; /* log tail. where recovery scan + * starts from */ + u64 last_cp_seq; /* log tail sequence */ + + sector_t log_start; /* log head. where new data appends */ + u64 seq; /* log head sequence */ + + sector_t next_checkpoint; + u64 next_cp_seq; + + struct mutex io_mutex; + struct r5l_io_unit *current_io; /* current io_unit accepting new data */ + + spinlock_t io_list_lock; + struct list_head running_ios; /* io_units which are still running, + * and have not yet been completely + * written to the log */ + struct list_head io_end_ios; /* io_units which have been completely + * written to the log but not yet written + * to the RAID */ + struct list_head flushing_ios; /* io_units which are waiting for log + * cache flush */ + struct list_head finished_ios; /* io_units which settle down in log disk */ + struct bio flush_bio; + + struct kmem_cache *io_kc; + + struct md_thread *reclaim_thread; + unsigned long reclaim_target; /* number of space that need to be + * reclaimed. if it's 0, reclaim spaces + * used by io_units which are in + * IO_UNIT_STRIPE_END state (eg, reclaim + * dones't wait for specific io_unit + * switching to IO_UNIT_STRIPE_END + * state) */ + wait_queue_head_t iounit_wait; + + struct list_head no_space_stripes; /* pending stripes, log has no space */ + spinlock_t no_space_stripes_lock; + + bool need_cache_flush; + bool in_teardown; +}; + +/* + * an IO range starts from a meta data block and end at the next meta data + * block. The io unit's the meta data block tracks data/parity followed it. io + * unit is written to log disk with normal write, as we always flush log disk + * first and then start move data to raid disks, there is no requirement to + * write io unit with FLUSH/FUA + */ +struct r5l_io_unit { + struct r5l_log *log; + + struct page *meta_page; /* store meta block */ + int meta_offset; /* current offset in meta_page */ + + struct bio *current_bio;/* current_bio accepting new data */ + + atomic_t pending_stripe;/* how many stripes not flushed to raid */ + u64 seq; /* seq number of the metablock */ + sector_t log_start; /* where the io_unit starts */ + sector_t log_end; /* where the io_unit ends */ + struct list_head log_sibling; /* log->running_ios */ + struct list_head stripe_list; /* stripes added to the io_unit */ + + int state; + bool need_split_bio; +}; + +/* r5l_io_unit state */ +enum r5l_io_unit_state { + IO_UNIT_RUNNING = 0, /* accepting new IO */ + IO_UNIT_IO_START = 1, /* io_unit bio start writing to log, + * don't accepting new bio */ + IO_UNIT_IO_END = 2, /* io_unit bio finish writing to log */ + IO_UNIT_STRIPE_END = 3, /* stripes data finished writing to raid */ +}; + +static sector_t r5l_ring_add(struct r5l_log *log, sector_t start, sector_t inc) +{ + start += inc; + if (start >= log->device_size) + start = start - log->device_size; + return start; +} + +static sector_t r5l_ring_distance(struct r5l_log *log, sector_t start, + sector_t end) +{ + if (end >= start) + return end - start; + else + return end + log->device_size - start; +} + +static bool r5l_has_free_space(struct r5l_log *log, sector_t size) +{ + sector_t used_size; + + used_size = r5l_ring_distance(log, log->last_checkpoint, + log->log_start); + + return log->device_size > used_size + size; +} + +static void r5l_free_io_unit(struct r5l_log *log, struct r5l_io_unit *io) +{ + __free_page(io->meta_page); + kmem_cache_free(log->io_kc, io); +} + +static void r5l_move_io_unit_list(struct list_head *from, struct list_head *to, + enum r5l_io_unit_state state) +{ + struct r5l_io_unit *io; + + while (!list_empty(from)) { + io = list_first_entry(from, struct r5l_io_unit, log_sibling); + /* don't change list order */ + if (io->state >= state) + list_move_tail(&io->log_sibling, to); + else + break; + } +} + +static void __r5l_set_io_unit_state(struct r5l_io_unit *io, + enum r5l_io_unit_state state) +{ + if (WARN_ON(io->state >= state)) + return; + io->state = state; +} + +static void r5l_io_run_stripes(struct r5l_io_unit *io) +{ + struct stripe_head *sh, *next; + + list_for_each_entry_safe(sh, next, &io->stripe_list, log_list) { + list_del_init(&sh->log_list); + set_bit(STRIPE_HANDLE, &sh->state); + raid5_release_stripe(sh); + } +} + +static void r5l_log_run_stripes(struct r5l_log *log) +{ + struct r5l_io_unit *io, *next; + + assert_spin_locked(&log->io_list_lock); + + list_for_each_entry_safe(io, next, &log->running_ios, log_sibling) { + /* don't change list order */ + if (io->state < IO_UNIT_IO_END) + break; + + list_move_tail(&io->log_sibling, &log->finished_ios); + r5l_io_run_stripes(io); + } +} + +static void r5l_log_endio(struct bio *bio) +{ + struct r5l_io_unit *io = bio->bi_private; + struct r5l_log *log = io->log; + unsigned long flags; + + if (bio->bi_error) + md_error(log->rdev->mddev, log->rdev); + + bio_put(bio); + + spin_lock_irqsave(&log->io_list_lock, flags); + __r5l_set_io_unit_state(io, IO_UNIT_IO_END); + if (log->need_cache_flush) + r5l_move_io_unit_list(&log->running_ios, &log->io_end_ios, + IO_UNIT_IO_END); + else + r5l_log_run_stripes(log); + spin_unlock_irqrestore(&log->io_list_lock, flags); + + if (log->need_cache_flush) + md_wakeup_thread(log->rdev->mddev->thread); +} + +static void r5l_submit_current_io(struct r5l_log *log) +{ + struct r5l_io_unit *io = log->current_io; + struct r5l_meta_block *block; + unsigned long flags; + u32 crc; + + if (!io) + return; + + block = page_address(io->meta_page); + block->meta_size = cpu_to_le32(io->meta_offset); + crc = crc32c_le(log->uuid_checksum, block, PAGE_SIZE); + block->checksum = cpu_to_le32(crc); + + log->current_io = NULL; + spin_lock_irqsave(&log->io_list_lock, flags); + __r5l_set_io_unit_state(io, IO_UNIT_IO_START); + spin_unlock_irqrestore(&log->io_list_lock, flags); + + submit_bio(WRITE, io->current_bio); +} + +static struct bio *r5l_bio_alloc(struct r5l_log *log) +{ + struct bio *bio = bio_kmalloc(GFP_NOIO | __GFP_NOFAIL, BIO_MAX_PAGES); + + bio->bi_rw = WRITE; + bio->bi_bdev = log->rdev->bdev; + bio->bi_iter.bi_sector = log->rdev->data_offset + log->log_start; + + return bio; +} + +static void r5_reserve_log_entry(struct r5l_log *log, struct r5l_io_unit *io) +{ + log->log_start = r5l_ring_add(log, log->log_start, BLOCK_SECTORS); + + /* + * If we filled up the log device start from the beginning again, + * which will require a new bio. + * + * Note: for this to work properly the log size needs to me a multiple + * of BLOCK_SECTORS. + */ + if (log->log_start == 0) + io->need_split_bio = true; + + io->log_end = log->log_start; +} + +static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log) +{ + struct r5l_io_unit *io; + struct r5l_meta_block *block; + + /* We can't handle memory allocate failure so far */ + io = kmem_cache_zalloc(log->io_kc, GFP_NOIO | __GFP_NOFAIL); + io->log = log; + INIT_LIST_HEAD(&io->log_sibling); + INIT_LIST_HEAD(&io->stripe_list); + io->state = IO_UNIT_RUNNING; + + io->meta_page = alloc_page(GFP_NOIO | __GFP_NOFAIL | __GFP_ZERO); + block = page_address(io->meta_page); + block->magic = cpu_to_le32(R5LOG_MAGIC); + block->version = R5LOG_VERSION; + block->seq = cpu_to_le64(log->seq); + block->position = cpu_to_le64(log->log_start); + + io->log_start = log->log_start; + io->meta_offset = sizeof(struct r5l_meta_block); + io->seq = log->seq++; + + io->current_bio = r5l_bio_alloc(log); + io->current_bio->bi_end_io = r5l_log_endio; + io->current_bio->bi_private = io; + bio_add_page(io->current_bio, io->meta_page, PAGE_SIZE, 0); + + r5_reserve_log_entry(log, io); + + spin_lock_irq(&log->io_list_lock); + list_add_tail(&io->log_sibling, &log->running_ios); + spin_unlock_irq(&log->io_list_lock); + + return io; +} + +static int r5l_get_meta(struct r5l_log *log, unsigned int payload_size) +{ + if (log->current_io && + log->current_io->meta_offset + payload_size > PAGE_SIZE) + r5l_submit_current_io(log); + + if (!log->current_io) + log->current_io = r5l_new_meta(log); + return 0; +} + +static void r5l_append_payload_meta(struct r5l_log *log, u16 type, + sector_t location, + u32 checksum1, u32 checksum2, + bool checksum2_valid) +{ + struct r5l_io_unit *io = log->current_io; + struct r5l_payload_data_parity *payload; + + payload = page_address(io->meta_page) + io->meta_offset; + payload->header.type = cpu_to_le16(type); + payload->header.flags = cpu_to_le16(0); + payload->size = cpu_to_le32((1 + !!checksum2_valid) << + (PAGE_SHIFT - 9)); + payload->location = cpu_to_le64(location); + payload->checksum[0] = cpu_to_le32(checksum1); + if (checksum2_valid) + payload->checksum[1] = cpu_to_le32(checksum2); + + io->meta_offset += sizeof(struct r5l_payload_data_parity) + + sizeof(__le32) * (1 + !!checksum2_valid); +} + +static void r5l_append_payload_page(struct r5l_log *log, struct page *page) +{ + struct r5l_io_unit *io = log->current_io; + + if (io->need_split_bio) { + struct bio *prev = io->current_bio; + + io->current_bio = r5l_bio_alloc(log); + bio_chain(io->current_bio, prev); + + submit_bio(WRITE, prev); + } + + if (!bio_add_page(io->current_bio, page, PAGE_SIZE, 0)) + BUG(); + + r5_reserve_log_entry(log, io); +} + +static void r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh, + int data_pages, int parity_pages) +{ + int i; + int meta_size; + struct r5l_io_unit *io; + + meta_size = + ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32)) + * data_pages) + + sizeof(struct r5l_payload_data_parity) + + sizeof(__le32) * parity_pages; + + r5l_get_meta(log, meta_size); + io = log->current_io; + + for (i = 0; i < sh->disks; i++) { + if (!test_bit(R5_Wantwrite, &sh->dev[i].flags)) + continue; + if (i == sh->pd_idx || i == sh->qd_idx) + continue; + r5l_append_payload_meta(log, R5LOG_PAYLOAD_DATA, + raid5_compute_blocknr(sh, i, 0), + sh->dev[i].log_checksum, 0, false); + r5l_append_payload_page(log, sh->dev[i].page); + } + + if (sh->qd_idx >= 0) { + r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY, + sh->sector, sh->dev[sh->pd_idx].log_checksum, + sh->dev[sh->qd_idx].log_checksum, true); + r5l_append_payload_page(log, sh->dev[sh->pd_idx].page); + r5l_append_payload_page(log, sh->dev[sh->qd_idx].page); + } else { + r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY, + sh->sector, sh->dev[sh->pd_idx].log_checksum, + 0, false); + r5l_append_payload_page(log, sh->dev[sh->pd_idx].page); + } + + list_add_tail(&sh->log_list, &io->stripe_list); + atomic_inc(&io->pending_stripe); + sh->log_io = io; +} + +static void r5l_wake_reclaim(struct r5l_log *log, sector_t space); +/* + * running in raid5d, where reclaim could wait for raid5d too (when it flushes + * data from log to raid disks), so we shouldn't wait for reclaim here + */ +int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh) +{ + int write_disks = 0; + int data_pages, parity_pages; + int meta_size; + int reserve; + int i; + + if (!log) + return -EAGAIN; + /* Don't support stripe batch */ + if (sh->log_io || !test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags) || + test_bit(STRIPE_SYNCING, &sh->state)) { + /* the stripe is written to log, we start writing it to raid */ + clear_bit(STRIPE_LOG_TRAPPED, &sh->state); + return -EAGAIN; + } + + for (i = 0; i < sh->disks; i++) { + void *addr; + + if (!test_bit(R5_Wantwrite, &sh->dev[i].flags)) + continue; + write_disks++; + /* checksum is already calculated in last run */ + if (test_bit(STRIPE_LOG_TRAPPED, &sh->state)) + continue; + addr = kmap_atomic(sh->dev[i].page); + sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum, + addr, PAGE_SIZE); + kunmap_atomic(addr); + } + parity_pages = 1 + !!(sh->qd_idx >= 0); + data_pages = write_disks - parity_pages; + + meta_size = + ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32)) + * data_pages) + + sizeof(struct r5l_payload_data_parity) + + sizeof(__le32) * parity_pages; + /* Doesn't work with very big raid array */ + if (meta_size + sizeof(struct r5l_meta_block) > PAGE_SIZE) + return -EINVAL; + + set_bit(STRIPE_LOG_TRAPPED, &sh->state); + /* + * The stripe must enter state machine again to finish the write, so + * don't delay. + */ + clear_bit(STRIPE_DELAYED, &sh->state); + atomic_inc(&sh->count); + + mutex_lock(&log->io_mutex); + /* meta + data */ + reserve = (1 + write_disks) << (PAGE_SHIFT - 9); + if (r5l_has_free_space(log, reserve)) + r5l_log_stripe(log, sh, data_pages, parity_pages); + else { + spin_lock(&log->no_space_stripes_lock); + list_add_tail(&sh->log_list, &log->no_space_stripes); + spin_unlock(&log->no_space_stripes_lock); + + r5l_wake_reclaim(log, reserve); + } + mutex_unlock(&log->io_mutex); + + return 0; +} + +void r5l_write_stripe_run(struct r5l_log *log) +{ + if (!log) + return; + mutex_lock(&log->io_mutex); + r5l_submit_current_io(log); + mutex_unlock(&log->io_mutex); +} + +int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio) +{ + if (!log) + return -ENODEV; + /* + * we flush log disk cache first, then write stripe data to raid disks. + * So if bio is finished, the log disk cache is flushed already. The + * recovery guarantees we can recovery the bio from log disk, so we + * don't need to flush again + */ + if (bio->bi_iter.bi_size == 0) { + bio_endio(bio); + return 0; + } + bio->bi_rw &= ~REQ_FLUSH; + return -EAGAIN; +} + +/* This will run after log space is reclaimed */ +static void r5l_run_no_space_stripes(struct r5l_log *log) +{ + struct stripe_head *sh; + + spin_lock(&log->no_space_stripes_lock); + while (!list_empty(&log->no_space_stripes)) { + sh = list_first_entry(&log->no_space_stripes, + struct stripe_head, log_list); + list_del_init(&sh->log_list); + set_bit(STRIPE_HANDLE, &sh->state); + raid5_release_stripe(sh); + } + spin_unlock(&log->no_space_stripes_lock); +} + +static sector_t r5l_reclaimable_space(struct r5l_log *log) +{ + return r5l_ring_distance(log, log->last_checkpoint, + log->next_checkpoint); +} + +static bool r5l_complete_finished_ios(struct r5l_log *log) +{ + struct r5l_io_unit *io, *next; + bool found = false; + + assert_spin_locked(&log->io_list_lock); + + list_for_each_entry_safe(io, next, &log->finished_ios, log_sibling) { + /* don't change list order */ + if (io->state < IO_UNIT_STRIPE_END) + break; + + log->next_checkpoint = io->log_start; + log->next_cp_seq = io->seq; + + list_del(&io->log_sibling); + r5l_free_io_unit(log, io); + + found = true; + } + + return found; +} + +static void __r5l_stripe_write_finished(struct r5l_io_unit *io) +{ + struct r5l_log *log = io->log; + unsigned long flags; + + spin_lock_irqsave(&log->io_list_lock, flags); + __r5l_set_io_unit_state(io, IO_UNIT_STRIPE_END); + + if (!r5l_complete_finished_ios(log)) { + spin_unlock_irqrestore(&log->io_list_lock, flags); + return; + } + + if (r5l_reclaimable_space(log) > log->max_free_space) + r5l_wake_reclaim(log, 0); + + spin_unlock_irqrestore(&log->io_list_lock, flags); + wake_up(&log->iounit_wait); +} + +void r5l_stripe_write_finished(struct stripe_head *sh) +{ + struct r5l_io_unit *io; + + io = sh->log_io; + sh->log_io = NULL; + + if (io && atomic_dec_and_test(&io->pending_stripe)) + __r5l_stripe_write_finished(io); +} + +static void r5l_log_flush_endio(struct bio *bio) +{ + struct r5l_log *log = container_of(bio, struct r5l_log, + flush_bio); + unsigned long flags; + struct r5l_io_unit *io; + + if (bio->bi_error) + md_error(log->rdev->mddev, log->rdev); + + spin_lock_irqsave(&log->io_list_lock, flags); + list_for_each_entry(io, &log->flushing_ios, log_sibling) + r5l_io_run_stripes(io); + list_splice_tail_init(&log->flushing_ios, &log->finished_ios); + spin_unlock_irqrestore(&log->io_list_lock, flags); +} + +/* + * Starting dispatch IO to raid. + * io_unit(meta) consists of a log. There is one situation we want to avoid. A + * broken meta in the middle of a log causes recovery can't find meta at the + * head of log. If operations require meta at the head persistent in log, we + * must make sure meta before it persistent in log too. A case is: + * + * stripe data/parity is in log, we start write stripe to raid disks. stripe + * data/parity must be persistent in log before we do the write to raid disks. + * + * The solution is we restrictly maintain io_unit list order. In this case, we + * only write stripes of an io_unit to raid disks till the io_unit is the first + * one whose data/parity is in log. + */ +void r5l_flush_stripe_to_raid(struct r5l_log *log) +{ + bool do_flush; + + if (!log || !log->need_cache_flush) + return; + + spin_lock_irq(&log->io_list_lock); + /* flush bio is running */ + if (!list_empty(&log->flushing_ios)) { + spin_unlock_irq(&log->io_list_lock); + return; + } + list_splice_tail_init(&log->io_end_ios, &log->flushing_ios); + do_flush = !list_empty(&log->flushing_ios); + spin_unlock_irq(&log->io_list_lock); + + if (!do_flush) + return; + bio_reset(&log->flush_bio); + log->flush_bio.bi_bdev = log->rdev->bdev; + log->flush_bio.bi_end_io = r5l_log_flush_endio; + submit_bio(WRITE_FLUSH, &log->flush_bio); +} + +static void r5l_write_super(struct r5l_log *log, sector_t cp); +static void r5l_write_super_and_discard_space(struct r5l_log *log, + sector_t end) +{ + struct block_device *bdev = log->rdev->bdev; + struct mddev *mddev; + + r5l_write_super(log, end); + + if (!blk_queue_discard(bdev_get_queue(bdev))) + return; + + mddev = log->rdev->mddev; + /* + * This is to avoid a deadlock. r5l_quiesce holds reconfig_mutex and + * wait for this thread to finish. This thread waits for + * MD_CHANGE_PENDING clear, which is supposed to be done in + * md_check_recovery(). md_check_recovery() tries to get + * reconfig_mutex. Since r5l_quiesce already holds the mutex, + * md_check_recovery() fails, so the PENDING never get cleared. The + * in_teardown check workaround this issue. + */ + if (!log->in_teardown) { + set_bit(MD_CHANGE_DEVS, &mddev->flags); + set_bit(MD_CHANGE_PENDING, &mddev->flags); + md_wakeup_thread(mddev->thread); + wait_event(mddev->sb_wait, + !test_bit(MD_CHANGE_PENDING, &mddev->flags) || + log->in_teardown); + /* + * r5l_quiesce could run after in_teardown check and hold + * mutex first. Superblock might get updated twice. + */ + if (log->in_teardown) + md_update_sb(mddev, 1); + } else { + WARN_ON(!mddev_is_locked(mddev)); + md_update_sb(mddev, 1); + } + + /* discard IO error really doesn't matter, ignore it */ + if (log->last_checkpoint < end) { + blkdev_issue_discard(bdev, + log->last_checkpoint + log->rdev->data_offset, + end - log->last_checkpoint, GFP_NOIO, 0); + } else { + blkdev_issue_discard(bdev, + log->last_checkpoint + log->rdev->data_offset, + log->device_size - log->last_checkpoint, + GFP_NOIO, 0); + blkdev_issue_discard(bdev, log->rdev->data_offset, end, + GFP_NOIO, 0); + } +} + + +static void r5l_do_reclaim(struct r5l_log *log) +{ + sector_t reclaim_target = xchg(&log->reclaim_target, 0); + sector_t reclaimable; + sector_t next_checkpoint; + u64 next_cp_seq; + + spin_lock_irq(&log->io_list_lock); + /* + * move proper io_unit to reclaim list. We should not change the order. + * reclaimable/unreclaimable io_unit can be mixed in the list, we + * shouldn't reuse space of an unreclaimable io_unit + */ + while (1) { + reclaimable = r5l_reclaimable_space(log); + if (reclaimable >= reclaim_target || + (list_empty(&log->running_ios) && + list_empty(&log->io_end_ios) && + list_empty(&log->flushing_ios) && + list_empty(&log->finished_ios))) + break; + + md_wakeup_thread(log->rdev->mddev->thread); + wait_event_lock_irq(log->iounit_wait, + r5l_reclaimable_space(log) > reclaimable, + log->io_list_lock); + } + + next_checkpoint = log->next_checkpoint; + next_cp_seq = log->next_cp_seq; + spin_unlock_irq(&log->io_list_lock); + + BUG_ON(reclaimable < 0); + if (reclaimable == 0) + return; + + /* + * write_super will flush cache of each raid disk. We must write super + * here, because the log area might be reused soon and we don't want to + * confuse recovery + */ + r5l_write_super_and_discard_space(log, next_checkpoint); + + mutex_lock(&log->io_mutex); + log->last_checkpoint = next_checkpoint; + log->last_cp_seq = next_cp_seq; + mutex_unlock(&log->io_mutex); + + r5l_run_no_space_stripes(log); +} + +static void r5l_reclaim_thread(struct md_thread *thread) +{ + struct mddev *mddev = thread->mddev; + struct r5conf *conf = mddev->private; + struct r5l_log *log = conf->log; + + if (!log) + return; + r5l_do_reclaim(log); +} + +static void r5l_wake_reclaim(struct r5l_log *log, sector_t space) +{ + unsigned long target; + unsigned long new = (unsigned long)space; /* overflow in theory */ + + do { + target = log->reclaim_target; + if (new < target) + return; + } while (cmpxchg(&log->reclaim_target, target, new) != target); + md_wakeup_thread(log->reclaim_thread); +} + +void r5l_quiesce(struct r5l_log *log, int state) +{ + struct mddev *mddev; + if (!log || state == 2) + return; + if (state == 0) { + log->in_teardown = 0; + log->reclaim_thread = md_register_thread(r5l_reclaim_thread, + log->rdev->mddev, "reclaim"); + } else if (state == 1) { + /* + * at this point all stripes are finished, so io_unit is at + * least in STRIPE_END state + */ + log->in_teardown = 1; + /* make sure r5l_write_super_and_discard_space exits */ + mddev = log->rdev->mddev; + wake_up(&mddev->sb_wait); + r5l_wake_reclaim(log, -1L); + md_unregister_thread(&log->reclaim_thread); + r5l_do_reclaim(log); + } +} + +bool r5l_log_disk_error(struct r5conf *conf) +{ + /* don't allow write if journal disk is missing */ + if (!conf->log) + return test_bit(MD_HAS_JOURNAL, &conf->mddev->flags); + return test_bit(Faulty, &conf->log->rdev->flags); +} + +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 = crc32c_le(log->uuid_checksum, 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 = 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 */ + 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 = crc32c_le(log->uuid_checksum, 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) +{ + 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; +} + +static void r5l_write_super(struct r5l_log *log, sector_t cp) +{ + struct mddev *mddev = log->rdev->mddev; + + log->rdev->journal_tail = cp; + set_bit(MD_CHANGE_DEVS, &mddev->flags); +} + +static int r5l_load_log(struct r5l_log *log) +{ + struct md_rdev *rdev = log->rdev; + struct page *page; + struct r5l_meta_block *mb; + sector_t cp = log->rdev->journal_tail; + u32 stored_crc, expected_crc; + bool create_super = false; + int ret; + + /* Make sure it's valid */ + if (cp >= rdev->sectors || round_down(cp, BLOCK_SECTORS) != cp) + cp = 0; + page = alloc_page(GFP_KERNEL); + if (!page) + return -ENOMEM; + + if (!sync_page_io(rdev, cp, PAGE_SIZE, page, READ, false)) { + ret = -EIO; + goto ioerr; + } + mb = page_address(page); + + if (le32_to_cpu(mb->magic) != R5LOG_MAGIC || + mb->version != R5LOG_VERSION) { + create_super = true; + goto create; + } + stored_crc = le32_to_cpu(mb->checksum); + mb->checksum = 0; + expected_crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE); + if (stored_crc != expected_crc) { + create_super = true; + goto create; + } + if (le64_to_cpu(mb->position) != cp) { + create_super = true; + goto create; + } +create: + if (create_super) { + log->last_cp_seq = prandom_u32(); + cp = 0; + /* + * Make sure super points to correct address. Log might have + * data very soon. If super hasn't correct log tail address, + * recovery can't find the log + */ + r5l_write_super(log, cp); + } else + log->last_cp_seq = le64_to_cpu(mb->seq); + + log->device_size = round_down(rdev->sectors, BLOCK_SECTORS); + log->max_free_space = log->device_size >> RECLAIM_MAX_FREE_SPACE_SHIFT; + if (log->max_free_space > RECLAIM_MAX_FREE_SPACE) + log->max_free_space = RECLAIM_MAX_FREE_SPACE; + log->last_checkpoint = cp; + + __free_page(page); + + return r5l_recovery_log(log); +ioerr: + __free_page(page); + return ret; +} + +int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) +{ + struct r5l_log *log; + + if (PAGE_SIZE != 4096) + return -EINVAL; + log = kzalloc(sizeof(*log), GFP_KERNEL); + if (!log) + return -ENOMEM; + log->rdev = rdev; + + log->need_cache_flush = (rdev->bdev->bd_disk->queue->flush_flags != 0); + + log->uuid_checksum = crc32c_le(~0, rdev->mddev->uuid, + sizeof(rdev->mddev->uuid)); + + mutex_init(&log->io_mutex); + + spin_lock_init(&log->io_list_lock); + INIT_LIST_HEAD(&log->running_ios); + INIT_LIST_HEAD(&log->io_end_ios); + INIT_LIST_HEAD(&log->flushing_ios); + INIT_LIST_HEAD(&log->finished_ios); + bio_init(&log->flush_bio); + + log->io_kc = KMEM_CACHE(r5l_io_unit, 0); + if (!log->io_kc) + goto io_kc; + + log->reclaim_thread = md_register_thread(r5l_reclaim_thread, + log->rdev->mddev, "reclaim"); + if (!log->reclaim_thread) + goto reclaim_thread; + init_waitqueue_head(&log->iounit_wait); + + INIT_LIST_HEAD(&log->no_space_stripes); + spin_lock_init(&log->no_space_stripes_lock); + + if (r5l_load_log(log)) + goto error; + + conf->log = log; + return 0; +error: + md_unregister_thread(&log->reclaim_thread); +reclaim_thread: + kmem_cache_destroy(log->io_kc); +io_kc: + kfree(log); + return -EINVAL; +} + +void r5l_exit_log(struct r5l_log *log) +{ + md_unregister_thread(&log->reclaim_thread); + kmem_cache_destroy(log->io_kc); + kfree(log); +} |