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Diffstat (limited to '')
| -rw-r--r-- | drivers/md/raid5-cache.c | 3187 |
1 files changed, 3187 insertions, 0 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c new file mode 100644 index 000000000..4337ae0e6 --- /dev/null +++ b/drivers/md/raid5-cache.c @@ -0,0 +1,3187 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2015 Shaohua Li <shli@fb.com> + * Copyright (C) 2016 Song Liu <songliubraving@fb.com> + */ +#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 <linux/kthread.h> +#include <linux/types.h> +#include "md.h" +#include "raid5.h" +#include "md-bitmap.h" +#include "raid5-log.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) +#define BLOCK_SECTOR_SHIFT (3) + +/* + * log->max_free_space is min(1/4 disk size, 10G reclaimable space). + * + * In write through mode, the reclaim runs every log->max_free_space. + * This can prevent the recovery scans for too long + */ +#define RECLAIM_MAX_FREE_SPACE (10 * 1024 * 1024 * 2) /* sector */ +#define RECLAIM_MAX_FREE_SPACE_SHIFT (2) + +/* wake up reclaim thread periodically */ +#define R5C_RECLAIM_WAKEUP_INTERVAL (30 * HZ) +/* start flush with these full stripes */ +#define R5C_FULL_STRIPE_FLUSH_BATCH(conf) (conf->max_nr_stripes / 4) +/* reclaim stripes in groups */ +#define R5C_RECLAIM_STRIPE_GROUP (NR_STRIPE_HASH_LOCKS * 2) + +/* + * We only need 2 bios per I/O unit to make progress, but ensure we + * have a few more available to not get too tight. + */ +#define R5L_POOL_SIZE 4 + +static char *r5c_journal_mode_str[] = {"write-through", + "write-back"}; +/* + * raid5 cache state machine + * + * With the RAID cache, each stripe works in two phases: + * - caching phase + * - writing-out phase + * + * These two phases are controlled by bit STRIPE_R5C_CACHING: + * if STRIPE_R5C_CACHING == 0, the stripe is in writing-out phase + * if STRIPE_R5C_CACHING == 1, the stripe is in caching phase + * + * When there is no journal, or the journal is in write-through mode, + * the stripe is always in writing-out phase. + * + * For write-back journal, the stripe is sent to caching phase on write + * (r5c_try_caching_write). r5c_make_stripe_write_out() kicks off + * the write-out phase by clearing STRIPE_R5C_CACHING. + * + * Stripes in caching phase do not write the raid disks. Instead, all + * writes are committed from the log device. Therefore, a stripe in + * caching phase handles writes as: + * - write to log device + * - return IO + * + * Stripes in writing-out phase handle writes as: + * - calculate parity + * - write pending data and parity to journal + * - write data and parity to raid disks + * - return IO for pending writes + */ + +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; + + 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 list_head no_mem_stripes; /* pending stripes, -ENOMEM */ + + struct kmem_cache *io_kc; + mempool_t io_pool; + struct bio_set bs; + mempool_t meta_pool; + + 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; + + /* for r5c_cache */ + enum r5c_journal_mode r5c_journal_mode; + + /* all stripes in r5cache, in the order of seq at sh->log_start */ + struct list_head stripe_in_journal_list; + + spinlock_t stripe_in_journal_lock; + atomic_t stripe_in_journal_count; + + /* to submit async io_units, to fulfill ordering of flush */ + struct work_struct deferred_io_work; + /* to disable write back during in degraded mode */ + struct work_struct disable_writeback_work; + + /* to for chunk_aligned_read in writeback mode, details below */ + spinlock_t tree_lock; + struct radix_tree_root big_stripe_tree; +}; + +/* + * Enable chunk_aligned_read() with write back cache. + * + * Each chunk may contain more than one stripe (for example, a 256kB + * chunk contains 64 4kB-page, so this chunk contain 64 stripes). For + * chunk_aligned_read, these stripes are grouped into one "big_stripe". + * For each big_stripe, we count how many stripes of this big_stripe + * are in the write back cache. These data are tracked in a radix tree + * (big_stripe_tree). We use radix_tree item pointer as the counter. + * r5c_tree_index() is used to calculate keys for the radix tree. + * + * chunk_aligned_read() calls r5c_big_stripe_cached() to look up + * big_stripe of each chunk in the tree. If this big_stripe is in the + * tree, chunk_aligned_read() aborts. This look up is protected by + * rcu_read_lock(). + * + * It is necessary to remember whether a stripe is counted in + * big_stripe_tree. Instead of adding new flag, we reuses existing flags: + * STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE. If either of these + * two flags are set, the stripe is counted in big_stripe_tree. This + * requires moving set_bit(STRIPE_R5C_PARTIAL_STRIPE) to + * r5c_try_caching_write(); and moving clear_bit of + * STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE to + * r5c_finish_stripe_write_out(). + */ + +/* + * radix tree requests lowest 2 bits of data pointer to be 2b'00. + * So it is necessary to left shift the counter by 2 bits before using it + * as data pointer of the tree. + */ +#define R5C_RADIX_COUNT_SHIFT 2 + +/* + * calculate key for big_stripe_tree + * + * sect: align_bi->bi_iter.bi_sector or sh->sector + */ +static inline sector_t r5c_tree_index(struct r5conf *conf, + sector_t sect) +{ + sector_div(sect, conf->chunk_sectors); + return sect; +} + +/* + * 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; + struct bio *split_bio; + + unsigned int has_flush:1; /* include flush request */ + unsigned int has_fua:1; /* include fua request */ + unsigned int has_null_flush:1; /* include null flush request */ + unsigned int has_flush_payload:1; /* include flush payload */ + /* + * io isn't sent yet, flush/fua request can only be submitted till it's + * the first IO in running_ios list + */ + unsigned int io_deferred:1; + + struct bio_list flush_barriers; /* size == 0 flush bios */ +}; + +/* 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 */ +}; + +bool r5c_is_writeback(struct r5l_log *log) +{ + return (log != NULL && + log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK); +} + +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_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 +r5c_return_dev_pending_writes(struct r5conf *conf, struct r5dev *dev) +{ + struct bio *wbi, *wbi2; + + wbi = dev->written; + dev->written = NULL; + while (wbi && wbi->bi_iter.bi_sector < + dev->sector + RAID5_STRIPE_SECTORS(conf)) { + wbi2 = r5_next_bio(conf, wbi, dev->sector); + md_write_end(conf->mddev); + bio_endio(wbi); + wbi = wbi2; + } +} + +void r5c_handle_cached_data_endio(struct r5conf *conf, + struct stripe_head *sh, int disks) +{ + int i; + + for (i = sh->disks; i--; ) { + if (sh->dev[i].written) { + set_bit(R5_UPTODATE, &sh->dev[i].flags); + r5c_return_dev_pending_writes(conf, &sh->dev[i]); + md_bitmap_endwrite(conf->mddev->bitmap, sh->sector, + RAID5_STRIPE_SECTORS(conf), + !test_bit(STRIPE_DEGRADED, &sh->state), + 0); + } + } +} + +void r5l_wake_reclaim(struct r5l_log *log, sector_t space); + +/* Check whether we should flush some stripes to free up stripe cache */ +void r5c_check_stripe_cache_usage(struct r5conf *conf) +{ + int total_cached; + + if (!r5c_is_writeback(conf->log)) + return; + + total_cached = atomic_read(&conf->r5c_cached_partial_stripes) + + atomic_read(&conf->r5c_cached_full_stripes); + + /* + * The following condition is true for either of the following: + * - stripe cache pressure high: + * total_cached > 3/4 min_nr_stripes || + * empty_inactive_list_nr > 0 + * - stripe cache pressure moderate: + * total_cached > 1/2 min_nr_stripes + */ + if (total_cached > conf->min_nr_stripes * 1 / 2 || + atomic_read(&conf->empty_inactive_list_nr) > 0) + r5l_wake_reclaim(conf->log, 0); +} + +/* + * flush cache when there are R5C_FULL_STRIPE_FLUSH_BATCH or more full + * stripes in the cache + */ +void r5c_check_cached_full_stripe(struct r5conf *conf) +{ + if (!r5c_is_writeback(conf->log)) + return; + + /* + * wake up reclaim for R5C_FULL_STRIPE_FLUSH_BATCH cached stripes + * or a full stripe (chunk size / 4k stripes). + */ + if (atomic_read(&conf->r5c_cached_full_stripes) >= + min(R5C_FULL_STRIPE_FLUSH_BATCH(conf), + conf->chunk_sectors >> RAID5_STRIPE_SHIFT(conf))) + r5l_wake_reclaim(conf->log, 0); +} + +/* + * Total log space (in sectors) needed to flush all data in cache + * + * To avoid deadlock due to log space, it is necessary to reserve log + * space to flush critical stripes (stripes that occupying log space near + * last_checkpoint). This function helps check how much log space is + * required to flush all cached stripes. + * + * To reduce log space requirements, two mechanisms are used to give cache + * flush higher priorities: + * 1. In handle_stripe_dirtying() and schedule_reconstruction(), + * stripes ALREADY in journal can be flushed w/o pending writes; + * 2. In r5l_write_stripe() and r5c_cache_data(), stripes NOT in journal + * can be delayed (r5l_add_no_space_stripe). + * + * In cache flush, the stripe goes through 1 and then 2. For a stripe that + * already passed 1, flushing it requires at most (conf->max_degraded + 1) + * pages of journal space. For stripes that has not passed 1, flushing it + * requires (conf->raid_disks + 1) pages of journal space. There are at + * most (conf->group_cnt + 1) stripe that passed 1. So total journal space + * required to flush all cached stripes (in pages) is: + * + * (stripe_in_journal_count - group_cnt - 1) * (max_degraded + 1) + + * (group_cnt + 1) * (raid_disks + 1) + * or + * (stripe_in_journal_count) * (max_degraded + 1) + + * (group_cnt + 1) * (raid_disks - max_degraded) + */ +static sector_t r5c_log_required_to_flush_cache(struct r5conf *conf) +{ + struct r5l_log *log = conf->log; + + if (!r5c_is_writeback(log)) + return 0; + + return BLOCK_SECTORS * + ((conf->max_degraded + 1) * atomic_read(&log->stripe_in_journal_count) + + (conf->raid_disks - conf->max_degraded) * (conf->group_cnt + 1)); +} + +/* + * evaluate log space usage and update R5C_LOG_TIGHT and R5C_LOG_CRITICAL + * + * R5C_LOG_TIGHT is set when free space on the log device is less than 3x of + * reclaim_required_space. R5C_LOG_CRITICAL is set when free space on the log + * device is less than 2x of reclaim_required_space. + */ +static inline void r5c_update_log_state(struct r5l_log *log) +{ + struct r5conf *conf = log->rdev->mddev->private; + sector_t free_space; + sector_t reclaim_space; + bool wake_reclaim = false; + + if (!r5c_is_writeback(log)) + return; + + free_space = r5l_ring_distance(log, log->log_start, + log->last_checkpoint); + reclaim_space = r5c_log_required_to_flush_cache(conf); + if (free_space < 2 * reclaim_space) + set_bit(R5C_LOG_CRITICAL, &conf->cache_state); + else { + if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state)) + wake_reclaim = true; + clear_bit(R5C_LOG_CRITICAL, &conf->cache_state); + } + if (free_space < 3 * reclaim_space) + set_bit(R5C_LOG_TIGHT, &conf->cache_state); + else + clear_bit(R5C_LOG_TIGHT, &conf->cache_state); + + if (wake_reclaim) + r5l_wake_reclaim(log, 0); +} + +/* + * Put the stripe into writing-out phase by clearing STRIPE_R5C_CACHING. + * This function should only be called in write-back mode. + */ +void r5c_make_stripe_write_out(struct stripe_head *sh) +{ + struct r5conf *conf = sh->raid_conf; + struct r5l_log *log = conf->log; + + BUG_ON(!r5c_is_writeback(log)); + + WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state)); + clear_bit(STRIPE_R5C_CACHING, &sh->state); + + if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) + atomic_inc(&conf->preread_active_stripes); +} + +static void r5c_handle_data_cached(struct stripe_head *sh) +{ + int i; + + for (i = sh->disks; i--; ) + if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) { + set_bit(R5_InJournal, &sh->dev[i].flags); + clear_bit(R5_LOCKED, &sh->dev[i].flags); + } + clear_bit(STRIPE_LOG_TRAPPED, &sh->state); +} + +/* + * this journal write must contain full parity, + * it may also contain some data pages + */ +static void r5c_handle_parity_cached(struct stripe_head *sh) +{ + int i; + + for (i = sh->disks; i--; ) + if (test_bit(R5_InJournal, &sh->dev[i].flags)) + set_bit(R5_Wantwrite, &sh->dev[i].flags); +} + +/* + * Setting proper flags after writing (or flushing) data and/or parity to the + * log device. This is called from r5l_log_endio() or r5l_log_flush_endio(). + */ +static void r5c_finish_cache_stripe(struct stripe_head *sh) +{ + struct r5l_log *log = sh->raid_conf->log; + + if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) { + BUG_ON(test_bit(STRIPE_R5C_CACHING, &sh->state)); + /* + * Set R5_InJournal for parity dev[pd_idx]. This means + * all data AND parity in the journal. For RAID 6, it is + * NOT necessary to set the flag for dev[qd_idx], as the + * two parities are written out together. + */ + set_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags); + } else if (test_bit(STRIPE_R5C_CACHING, &sh->state)) { + r5c_handle_data_cached(sh); + } else { + r5c_handle_parity_cached(sh); + set_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags); + } +} + +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); + + r5c_finish_cache_stripe(sh); + + 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; + + lockdep_assert_held(&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_move_to_end_ios(struct r5l_log *log) +{ + struct r5l_io_unit *io, *next; + + lockdep_assert_held(&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->io_end_ios); + } +} + +static void __r5l_stripe_write_finished(struct r5l_io_unit *io); +static void r5l_log_endio(struct bio *bio) +{ + struct r5l_io_unit *io = bio->bi_private; + struct r5l_io_unit *io_deferred; + struct r5l_log *log = io->log; + unsigned long flags; + bool has_null_flush; + bool has_flush_payload; + + if (bio->bi_status) + md_error(log->rdev->mddev, log->rdev); + + bio_put(bio); + mempool_free(io->meta_page, &log->meta_pool); + + spin_lock_irqsave(&log->io_list_lock, flags); + __r5l_set_io_unit_state(io, IO_UNIT_IO_END); + + /* + * if the io doesn't not have null_flush or flush payload, + * it is not safe to access it after releasing io_list_lock. + * Therefore, it is necessary to check the condition with + * the lock held. + */ + has_null_flush = io->has_null_flush; + has_flush_payload = io->has_flush_payload; + + if (log->need_cache_flush && !list_empty(&io->stripe_list)) + r5l_move_to_end_ios(log); + else + r5l_log_run_stripes(log); + if (!list_empty(&log->running_ios)) { + /* + * FLUSH/FUA io_unit is deferred because of ordering, now we + * can dispatch it + */ + io_deferred = list_first_entry(&log->running_ios, + struct r5l_io_unit, log_sibling); + if (io_deferred->io_deferred) + schedule_work(&log->deferred_io_work); + } + + spin_unlock_irqrestore(&log->io_list_lock, flags); + + if (log->need_cache_flush) + md_wakeup_thread(log->rdev->mddev->thread); + + /* finish flush only io_unit and PAYLOAD_FLUSH only io_unit */ + if (has_null_flush) { + struct bio *bi; + + WARN_ON(bio_list_empty(&io->flush_barriers)); + while ((bi = bio_list_pop(&io->flush_barriers)) != NULL) { + bio_endio(bi); + if (atomic_dec_and_test(&io->pending_stripe)) { + __r5l_stripe_write_finished(io); + return; + } + } + } + /* decrease pending_stripe for flush payload */ + if (has_flush_payload) + if (atomic_dec_and_test(&io->pending_stripe)) + __r5l_stripe_write_finished(io); +} + +static void r5l_do_submit_io(struct r5l_log *log, struct r5l_io_unit *io) +{ + unsigned long flags; + + 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); + + /* + * In case of journal device failures, submit_bio will get error + * and calls endio, then active stripes will continue write + * process. Therefore, it is not necessary to check Faulty bit + * of journal device here. + * + * We can't check split_bio after current_bio is submitted. If + * io->split_bio is null, after current_bio is submitted, current_bio + * might already be completed and the io_unit is freed. We submit + * split_bio first to avoid the issue. + */ + if (io->split_bio) { + if (io->has_flush) + io->split_bio->bi_opf |= REQ_PREFLUSH; + if (io->has_fua) + io->split_bio->bi_opf |= REQ_FUA; + submit_bio(io->split_bio); + } + + if (io->has_flush) + io->current_bio->bi_opf |= REQ_PREFLUSH; + if (io->has_fua) + io->current_bio->bi_opf |= REQ_FUA; + submit_bio(io->current_bio); +} + +/* deferred io_unit will be dispatched here */ +static void r5l_submit_io_async(struct work_struct *work) +{ + struct r5l_log *log = container_of(work, struct r5l_log, + deferred_io_work); + struct r5l_io_unit *io = NULL; + unsigned long flags; + + spin_lock_irqsave(&log->io_list_lock, flags); + if (!list_empty(&log->running_ios)) { + io = list_first_entry(&log->running_ios, struct r5l_io_unit, + log_sibling); + if (!io->io_deferred) + io = NULL; + else + io->io_deferred = 0; + } + spin_unlock_irqrestore(&log->io_list_lock, flags); + if (io) + r5l_do_submit_io(log, io); +} + +static void r5c_disable_writeback_async(struct work_struct *work) +{ + struct r5l_log *log = container_of(work, struct r5l_log, + disable_writeback_work); + struct mddev *mddev = log->rdev->mddev; + struct r5conf *conf = mddev->private; + int locked = 0; + + if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) + return; + pr_info("md/raid:%s: Disabling writeback cache for degraded array.\n", + mdname(mddev)); + + /* wait superblock change before suspend */ + wait_event(mddev->sb_wait, + conf->log == NULL || + (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) && + (locked = mddev_trylock(mddev)))); + if (locked) { + mddev_suspend(mddev); + log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH; + mddev_resume(mddev); + mddev_unlock(mddev); + } +} + +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; + bool do_submit = true; + + 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); + if (io->has_flush || io->has_fua) { + if (io != list_first_entry(&log->running_ios, + struct r5l_io_unit, log_sibling)) { + io->io_deferred = 1; + do_submit = false; + } + } + spin_unlock_irqrestore(&log->io_list_lock, flags); + if (do_submit) + r5l_do_submit_io(log, io); +} + +static struct bio *r5l_bio_alloc(struct r5l_log *log) +{ + struct bio *bio = bio_alloc_bioset(GFP_NOIO, BIO_MAX_PAGES, &log->bs); + + bio_set_op_attrs(bio, REQ_OP_WRITE, 0); + bio_set_dev(bio, 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); + + r5c_update_log_state(log); + /* + * 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; + + io = mempool_alloc(&log->io_pool, GFP_ATOMIC); + if (!io) + return NULL; + memset(io, 0, sizeof(*io)); + + io->log = log; + INIT_LIST_HEAD(&io->log_sibling); + INIT_LIST_HEAD(&io->stripe_list); + bio_list_init(&io->flush_barriers); + io->state = IO_UNIT_RUNNING; + + io->meta_page = mempool_alloc(&log->meta_pool, GFP_NOIO); + block = page_address(io->meta_page); + clear_page(block); + 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); + if (!log->current_io) + return -ENOMEM; + } + + 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) { + BUG_ON(io->split_bio); + io->split_bio = io->current_bio; + io->current_bio = r5l_bio_alloc(log); + bio_chain(io->current_bio, io->split_bio); + io->need_split_bio = false; + } + + if (!bio_add_page(io->current_bio, page, PAGE_SIZE, 0)) + BUG(); + + r5_reserve_log_entry(log, io); +} + +static void r5l_append_flush_payload(struct r5l_log *log, sector_t sect) +{ + struct mddev *mddev = log->rdev->mddev; + struct r5conf *conf = mddev->private; + struct r5l_io_unit *io; + struct r5l_payload_flush *payload; + int meta_size; + + /* + * payload_flush requires extra writes to the journal. + * To avoid handling the extra IO in quiesce, just skip + * flush_payload + */ + if (conf->quiesce) + return; + + mutex_lock(&log->io_mutex); + meta_size = sizeof(struct r5l_payload_flush) + sizeof(__le64); + + if (r5l_get_meta(log, meta_size)) { + mutex_unlock(&log->io_mutex); + return; + } + + /* current implementation is one stripe per flush payload */ + io = log->current_io; + payload = page_address(io->meta_page) + io->meta_offset; + payload->header.type = cpu_to_le16(R5LOG_PAYLOAD_FLUSH); + payload->header.flags = cpu_to_le16(0); + payload->size = cpu_to_le32(sizeof(__le64)); + payload->flush_stripes[0] = cpu_to_le64(sect); + io->meta_offset += meta_size; + /* multiple flush payloads count as one pending_stripe */ + if (!io->has_flush_payload) { + io->has_flush_payload = 1; + atomic_inc(&io->pending_stripe); + } + mutex_unlock(&log->io_mutex); +} + +static int r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh, + int data_pages, int parity_pages) +{ + int i; + int meta_size; + int ret; + 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; + + ret = r5l_get_meta(log, meta_size); + if (ret) + return ret; + + io = log->current_io; + + if (test_and_clear_bit(STRIPE_R5C_PREFLUSH, &sh->state)) + io->has_flush = 1; + + for (i = 0; i < sh->disks; i++) { + if (!test_bit(R5_Wantwrite, &sh->dev[i].flags) || + test_bit(R5_InJournal, &sh->dev[i].flags)) + continue; + if (i == sh->pd_idx || i == sh->qd_idx) + continue; + if (test_bit(R5_WantFUA, &sh->dev[i].flags) && + log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK) { + io->has_fua = 1; + /* + * we need to flush journal to make sure recovery can + * reach the data with fua flag + */ + io->has_flush = 1; + } + 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 (parity_pages == 2) { + 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 if (parity_pages == 1) { + 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); + } else /* Just writing data, not parity, in caching phase */ + BUG_ON(parity_pages != 0); + + list_add_tail(&sh->log_list, &io->stripe_list); + atomic_inc(&io->pending_stripe); + sh->log_io = io; + + if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) + return 0; + + if (sh->log_start == MaxSector) { + BUG_ON(!list_empty(&sh->r5c)); + sh->log_start = io->log_start; + spin_lock_irq(&log->stripe_in_journal_lock); + list_add_tail(&sh->r5c, + &log->stripe_in_journal_list); + spin_unlock_irq(&log->stripe_in_journal_lock); + atomic_inc(&log->stripe_in_journal_count); + } + return 0; +} + +/* add stripe to no_space_stripes, and then wake up reclaim */ +static inline void r5l_add_no_space_stripe(struct r5l_log *log, + struct stripe_head *sh) +{ + spin_lock(&log->no_space_stripes_lock); + list_add_tail(&sh->log_list, &log->no_space_stripes); + spin_unlock(&log->no_space_stripes_lock); +} + +/* + * 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) +{ + struct r5conf *conf = sh->raid_conf; + int write_disks = 0; + int data_pages, parity_pages; + int reserve; + int i; + int ret = 0; + bool wake_reclaim = false; + + 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; + } + + WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state)); + + for (i = 0; i < sh->disks; i++) { + void *addr; + + if (!test_bit(R5_Wantwrite, &sh->dev[i].flags) || + test_bit(R5_InJournal, &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; + + 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 (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) { + if (!r5l_has_free_space(log, reserve)) { + r5l_add_no_space_stripe(log, sh); + wake_reclaim = true; + } else { + ret = r5l_log_stripe(log, sh, data_pages, parity_pages); + if (ret) { + spin_lock_irq(&log->io_list_lock); + list_add_tail(&sh->log_list, + &log->no_mem_stripes); + spin_unlock_irq(&log->io_list_lock); + } + } + } else { /* R5C_JOURNAL_MODE_WRITE_BACK */ + /* + * log space critical, do not process stripes that are + * not in cache yet (sh->log_start == MaxSector). + */ + if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) && + sh->log_start == MaxSector) { + r5l_add_no_space_stripe(log, sh); + wake_reclaim = true; + reserve = 0; + } else if (!r5l_has_free_space(log, reserve)) { + if (sh->log_start == log->last_checkpoint) + BUG(); + else + r5l_add_no_space_stripe(log, sh); + } else { + ret = r5l_log_stripe(log, sh, data_pages, parity_pages); + if (ret) { + spin_lock_irq(&log->io_list_lock); + list_add_tail(&sh->log_list, + &log->no_mem_stripes); + spin_unlock_irq(&log->io_list_lock); + } + } + } + + mutex_unlock(&log->io_mutex); + if (wake_reclaim) + r5l_wake_reclaim(log, reserve); + 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->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) { + /* + * in write through (journal only) + * 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_opf &= ~REQ_PREFLUSH; + } else { + /* write back (with cache) */ + if (bio->bi_iter.bi_size == 0) { + mutex_lock(&log->io_mutex); + r5l_get_meta(log, 0); + bio_list_add(&log->current_io->flush_barriers, bio); + log->current_io->has_flush = 1; + log->current_io->has_null_flush = 1; + atomic_inc(&log->current_io->pending_stripe); + r5l_submit_current_io(log); + mutex_unlock(&log->io_mutex); + return 0; + } + } + 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); +} + +/* + * calculate new last_checkpoint + * for write through mode, returns log->next_checkpoint + * for write back, returns log_start of first sh in stripe_in_journal_list + */ +static sector_t r5c_calculate_new_cp(struct r5conf *conf) +{ + struct stripe_head *sh; + struct r5l_log *log = conf->log; + sector_t new_cp; + unsigned long flags; + + if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) + return log->next_checkpoint; + + spin_lock_irqsave(&log->stripe_in_journal_lock, flags); + if (list_empty(&conf->log->stripe_in_journal_list)) { + /* all stripes flushed */ + spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags); + return log->next_checkpoint; + } + sh = list_first_entry(&conf->log->stripe_in_journal_list, + struct stripe_head, r5c); + new_cp = sh->log_start; + spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags); + return new_cp; +} + +static sector_t r5l_reclaimable_space(struct r5l_log *log) +{ + struct r5conf *conf = log->rdev->mddev->private; + + return r5l_ring_distance(log, log->last_checkpoint, + r5c_calculate_new_cp(conf)); +} + +static void r5l_run_no_mem_stripe(struct r5l_log *log) +{ + struct stripe_head *sh; + + lockdep_assert_held(&log->io_list_lock); + + if (!list_empty(&log->no_mem_stripes)) { + sh = list_first_entry(&log->no_mem_stripes, + struct stripe_head, log_list); + list_del_init(&sh->log_list); + set_bit(STRIPE_HANDLE, &sh->state); + raid5_release_stripe(sh); + } +} + +static bool r5l_complete_finished_ios(struct r5l_log *log) +{ + struct r5l_io_unit *io, *next; + bool found = false; + + lockdep_assert_held(&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; + + list_del(&io->log_sibling); + mempool_free(io, &log->io_pool); + r5l_run_no_mem_stripe(log); + + found = true; + } + + return found; +} + +static void __r5l_stripe_write_finished(struct r5l_io_unit *io) +{ + struct r5l_log *log = io->log; + struct r5conf *conf = log->rdev->mddev->private; + 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 || + test_bit(R5C_LOG_TIGHT, &conf->cache_state)) + 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_status) + 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); + bio_set_dev(&log->flush_bio, log->rdev->bdev); + log->flush_bio.bi_end_io = r5l_log_flush_endio; + log->flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH; + submit_bio(&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; + /* + * Discard could zero data, so before discard we must make sure + * superblock is updated to new log tail. Updating superblock (either + * directly call md_update_sb() or depend on md thread) must hold + * reconfig mutex. On the other hand, raid5_quiesce is called with + * reconfig_mutex hold. The first step of raid5_quiesce() is waitting + * for all IO finish, hence waitting for reclaim thread, while reclaim + * thread is calling this function and waitting for reconfig mutex. So + * there is a deadlock. We workaround this issue with a trylock. + * FIXME: we could miss discard if we can't take reconfig mutex + */ + set_mask_bits(&mddev->sb_flags, 0, + BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING)); + if (!mddev_trylock(mddev)) + return; + md_update_sb(mddev, 1); + mddev_unlock(mddev); + + /* 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); + } +} + +/* + * r5c_flush_stripe moves stripe from cached list to handle_list. When called, + * the stripe must be on r5c_cached_full_stripes or r5c_cached_partial_stripes. + * + * must hold conf->device_lock + */ +static void r5c_flush_stripe(struct r5conf *conf, struct stripe_head *sh) +{ + BUG_ON(list_empty(&sh->lru)); + BUG_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state)); + BUG_ON(test_bit(STRIPE_HANDLE, &sh->state)); + + /* + * The stripe is not ON_RELEASE_LIST, so it is safe to call + * raid5_release_stripe() while holding conf->device_lock + */ + BUG_ON(test_bit(STRIPE_ON_RELEASE_LIST, &sh->state)); + lockdep_assert_held(&conf->device_lock); + + list_del_init(&sh->lru); + atomic_inc(&sh->count); + + set_bit(STRIPE_HANDLE, &sh->state); + atomic_inc(&conf->active_stripes); + r5c_make_stripe_write_out(sh); + + if (test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) + atomic_inc(&conf->r5c_flushing_partial_stripes); + else + atomic_inc(&conf->r5c_flushing_full_stripes); + raid5_release_stripe(sh); +} + +/* + * if num == 0, flush all full stripes + * if num > 0, flush all full stripes. If less than num full stripes are + * flushed, flush some partial stripes until totally num stripes are + * flushed or there is no more cached stripes. + */ +void r5c_flush_cache(struct r5conf *conf, int num) +{ + int count; + struct stripe_head *sh, *next; + + lockdep_assert_held(&conf->device_lock); + if (!conf->log) + return; + + count = 0; + list_for_each_entry_safe(sh, next, &conf->r5c_full_stripe_list, lru) { + r5c_flush_stripe(conf, sh); + count++; + } + + if (count >= num) + return; + list_for_each_entry_safe(sh, next, + &conf->r5c_partial_stripe_list, lru) { + r5c_flush_stripe(conf, sh); + if (++count >= num) + break; + } +} + +static void r5c_do_reclaim(struct r5conf *conf) +{ + struct r5l_log *log = conf->log; + struct stripe_head *sh; + int count = 0; + unsigned long flags; + int total_cached; + int stripes_to_flush; + int flushing_partial, flushing_full; + + if (!r5c_is_writeback(log)) + return; + + flushing_partial = atomic_read(&conf->r5c_flushing_partial_stripes); + flushing_full = atomic_read(&conf->r5c_flushing_full_stripes); + total_cached = atomic_read(&conf->r5c_cached_partial_stripes) + + atomic_read(&conf->r5c_cached_full_stripes) - + flushing_full - flushing_partial; + + if (total_cached > conf->min_nr_stripes * 3 / 4 || + atomic_read(&conf->empty_inactive_list_nr) > 0) + /* + * if stripe cache pressure high, flush all full stripes and + * some partial stripes + */ + stripes_to_flush = R5C_RECLAIM_STRIPE_GROUP; + else if (total_cached > conf->min_nr_stripes * 1 / 2 || + atomic_read(&conf->r5c_cached_full_stripes) - flushing_full > + R5C_FULL_STRIPE_FLUSH_BATCH(conf)) + /* + * if stripe cache pressure moderate, or if there is many full + * stripes,flush all full stripes + */ + stripes_to_flush = 0; + else + /* no need to flush */ + stripes_to_flush = -1; + + if (stripes_to_flush >= 0) { + spin_lock_irqsave(&conf->device_lock, flags); + r5c_flush_cache(conf, stripes_to_flush); + spin_unlock_irqrestore(&conf->device_lock, flags); + } + + /* if log space is tight, flush stripes on stripe_in_journal_list */ + if (test_bit(R5C_LOG_TIGHT, &conf->cache_state)) { + spin_lock_irqsave(&log->stripe_in_journal_lock, flags); + spin_lock(&conf->device_lock); + list_for_each_entry(sh, &log->stripe_in_journal_list, r5c) { + /* + * stripes on stripe_in_journal_list could be in any + * state of the stripe_cache state machine. In this + * case, we only want to flush stripe on + * r5c_cached_full/partial_stripes. The following + * condition makes sure the stripe is on one of the + * two lists. + */ + if (!list_empty(&sh->lru) && + !test_bit(STRIPE_HANDLE, &sh->state) && + atomic_read(&sh->count) == 0) { + r5c_flush_stripe(conf, sh); + if (count++ >= R5C_RECLAIM_STRIPE_GROUP) + break; + } + } + spin_unlock(&conf->device_lock); + spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags); + } + + if (!test_bit(R5C_LOG_CRITICAL, &conf->cache_state)) + r5l_run_no_space_stripes(log); + + md_wakeup_thread(conf->mddev->thread); +} + +static void r5l_do_reclaim(struct r5l_log *log) +{ + struct r5conf *conf = log->rdev->mddev->private; + sector_t reclaim_target = xchg(&log->reclaim_target, 0); + sector_t reclaimable; + sector_t next_checkpoint; + bool write_super; + + spin_lock_irq(&log->io_list_lock); + write_super = r5l_reclaimable_space(log) > log->max_free_space || + reclaim_target != 0 || !list_empty(&log->no_space_stripes); + /* + * 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 = r5c_calculate_new_cp(conf); + spin_unlock_irq(&log->io_list_lock); + + if (reclaimable == 0 || !write_super) + 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; + r5c_update_log_state(log); + 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; + r5c_do_reclaim(conf); + r5l_do_reclaim(log); +} + +void r5l_wake_reclaim(struct r5l_log *log, sector_t space) +{ + unsigned long target; + unsigned long new = (unsigned long)space; /* overflow in theory */ + + if (!log) + return; + 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 quiesce) +{ + struct mddev *mddev; + + if (quiesce) { + /* make sure r5l_write_super_and_discard_space exits */ + mddev = log->rdev->mddev; + wake_up(&mddev->sb_wait); + kthread_park(log->reclaim_thread->tsk); + r5l_wake_reclaim(log, MaxSector); + r5l_do_reclaim(log); + } else + kthread_unpark(log->reclaim_thread->tsk); +} + +bool r5l_log_disk_error(struct r5conf *conf) +{ + struct r5l_log *log; + bool ret; + /* don't allow write if journal disk is missing */ + rcu_read_lock(); + log = rcu_dereference(conf->log); + + if (!log) + ret = test_bit(MD_HAS_JOURNAL, &conf->mddev->flags); + else + ret = test_bit(Faulty, &log->rdev->flags); + rcu_read_unlock(); + return ret; +} + +#define R5L_RECOVERY_PAGE_POOL_SIZE 256 + +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 */ + int data_parity_stripes; /* number of data_parity stripes */ + int data_only_stripes; /* number of data_only stripes */ + struct list_head cached_list; + + /* + * read ahead page pool (ra_pool) + * in recovery, log is read sequentially. It is not efficient to + * read every page with sync_page_io(). The read ahead page pool + * reads multiple pages with one IO, so further log read can + * just copy data from the pool. + */ + struct page *ra_pool[R5L_RECOVERY_PAGE_POOL_SIZE]; + sector_t pool_offset; /* offset of first page in the pool */ + int total_pages; /* total allocated pages */ + int valid_pages; /* pages with valid data */ + struct bio *ra_bio; /* bio to do the read ahead */ +}; + +static int r5l_recovery_allocate_ra_pool(struct r5l_log *log, + struct r5l_recovery_ctx *ctx) +{ + struct page *page; + + ctx->ra_bio = bio_alloc_bioset(GFP_KERNEL, BIO_MAX_PAGES, &log->bs); + if (!ctx->ra_bio) + return -ENOMEM; + + ctx->valid_pages = 0; + ctx->total_pages = 0; + while (ctx->total_pages < R5L_RECOVERY_PAGE_POOL_SIZE) { + page = alloc_page(GFP_KERNEL); + + if (!page) + break; + ctx->ra_pool[ctx->total_pages] = page; + ctx->total_pages += 1; + } + + if (ctx->total_pages == 0) { + bio_put(ctx->ra_bio); + return -ENOMEM; + } + + ctx->pool_offset = 0; + return 0; +} + +static void r5l_recovery_free_ra_pool(struct r5l_log *log, + struct r5l_recovery_ctx *ctx) +{ + int i; + + for (i = 0; i < ctx->total_pages; ++i) + put_page(ctx->ra_pool[i]); + bio_put(ctx->ra_bio); +} + +/* + * fetch ctx->valid_pages pages from offset + * In normal cases, ctx->valid_pages == ctx->total_pages after the call. + * However, if the offset is close to the end of the journal device, + * ctx->valid_pages could be smaller than ctx->total_pages + */ +static int r5l_recovery_fetch_ra_pool(struct r5l_log *log, + struct r5l_recovery_ctx *ctx, + sector_t offset) +{ + bio_reset(ctx->ra_bio); + bio_set_dev(ctx->ra_bio, log->rdev->bdev); + bio_set_op_attrs(ctx->ra_bio, REQ_OP_READ, 0); + ctx->ra_bio->bi_iter.bi_sector = log->rdev->data_offset + offset; + + ctx->valid_pages = 0; + ctx->pool_offset = offset; + + while (ctx->valid_pages < ctx->total_pages) { + bio_add_page(ctx->ra_bio, + ctx->ra_pool[ctx->valid_pages], PAGE_SIZE, 0); + ctx->valid_pages += 1; + + offset = r5l_ring_add(log, offset, BLOCK_SECTORS); + + if (offset == 0) /* reached end of the device */ + break; + } + + return submit_bio_wait(ctx->ra_bio); +} + +/* + * try read a page from the read ahead page pool, if the page is not in the + * pool, call r5l_recovery_fetch_ra_pool + */ +static int r5l_recovery_read_page(struct r5l_log *log, + struct r5l_recovery_ctx *ctx, + struct page *page, + sector_t offset) +{ + int ret; + + if (offset < ctx->pool_offset || + offset >= ctx->pool_offset + ctx->valid_pages * BLOCK_SECTORS) { + ret = r5l_recovery_fetch_ra_pool(log, ctx, offset); + if (ret) + return ret; + } + + BUG_ON(offset < ctx->pool_offset || + offset >= ctx->pool_offset + ctx->valid_pages * BLOCK_SECTORS); + + memcpy(page_address(page), + page_address(ctx->ra_pool[(offset - ctx->pool_offset) >> + BLOCK_SECTOR_SHIFT]), + PAGE_SIZE); + return 0; +} + +static int r5l_recovery_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; + int ret; + + ret = r5l_recovery_read_page(log, ctx, page, ctx->pos); + if (ret != 0) + return ret; + + 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 void +r5l_recovery_create_empty_meta_block(struct r5l_log *log, + struct page *page, + sector_t pos, u64 seq) +{ + struct r5l_meta_block *mb; + + mb = page_address(page); + clear_page(mb); + 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); +} + +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; + + page = alloc_page(GFP_KERNEL); + if (!page) + return -ENOMEM; + r5l_recovery_create_empty_meta_block(log, page, pos, seq); + mb = page_address(page); + mb->checksum = cpu_to_le32(crc32c_le(log->uuid_checksum, + mb, PAGE_SIZE)); + if (!sync_page_io(log->rdev, pos, PAGE_SIZE, page, REQ_OP_WRITE, + REQ_SYNC | REQ_FUA, false)) { + __free_page(page); + return -EIO; + } + __free_page(page); + 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); + r5l_recovery_read_page(log, ctx, sh->dev[dd_idx].page, log_offset); + 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; + r5l_recovery_read_page(log, ctx, sh->dev[sh->pd_idx].page, log_offset); + 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) { + r5l_recovery_read_page( + log, ctx, sh->dev[sh->qd_idx].page, + r5l_ring_add(log, log_offset, BLOCK_SECTORS)); + 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, + sector_t stripe_sect, + int noblock) +{ + struct stripe_head *sh; + + sh = raid5_get_active_stripe(conf, stripe_sect, 0, noblock, 0); + if (!sh) + return NULL; /* no more stripe available */ + + r5l_recovery_reset_stripe(sh); + + 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 r5l_recovery_ctx *ctx, + struct page *page, + sector_t log_offset, __le32 log_checksum) +{ + void *addr; + u32 checksum; + + r5l_recovery_read_page(log, ctx, page, log_offset); + 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; + struct r5l_payload_flush *payload_flush; + + page = alloc_page(GFP_KERNEL); + if (!page) + return -ENOMEM; + + while (mb_offset < le32_to_cpu(mb->meta_size)) { + payload = (void *)mb + mb_offset; + payload_flush = (void *)mb + mb_offset; + + if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) { + if (r5l_recovery_verify_data_checksum( + log, ctx, page, log_offset, + payload->checksum[0]) < 0) + goto mismatch; + } else if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_PARITY) { + if (r5l_recovery_verify_data_checksum( + log, ctx, page, log_offset, + payload->checksum[0]) < 0) + goto mismatch; + if (conf->max_degraded == 2 && /* q for RAID 6 */ + r5l_recovery_verify_data_checksum( + log, ctx, page, + r5l_ring_add(log, log_offset, + BLOCK_SECTORS), + payload->checksum[1]) < 0) + goto mismatch; + } else if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) { + /* nothing to do for R5LOG_PAYLOAD_FLUSH here */ + } else /* not R5LOG_PAYLOAD_DATA/PARITY/FLUSH */ + goto mismatch; + + if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) { + mb_offset += sizeof(struct r5l_payload_flush) + + le32_to_cpu(payload_flush->size); + } else { + /* DATA or PARITY payload */ + 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; + struct r5l_payload_flush *payload_flush; + 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; + payload_flush = (void *)mb + mb_offset; + + if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) { + int i, count; + + count = le32_to_cpu(payload_flush->size) / sizeof(__le64); + for (i = 0; i < count; ++i) { + stripe_sect = le64_to_cpu(payload_flush->flush_stripes[i]); + sh = r5c_recovery_lookup_stripe(cached_stripe_list, + stripe_sect); + if (sh) { + WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state)); + r5l_recovery_reset_stripe(sh); + list_del_init(&sh->lru); + raid5_release_stripe(sh); + } + } + + mb_offset += sizeof(struct r5l_payload_flush) + + le32_to_cpu(payload_flush->size); + continue; + } + + /* DATA or PARITY payload */ + stripe_sect = (le16_to_cpu(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, stripe_sect, 1); + /* + * 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, stripe_sect, 1); + } + if (!sh) { + int new_size = conf->min_nr_stripes * 2; + pr_debug("md/raid:%s: Increasing stripe cache size to %d to recovery data on journal.\n", + mdname(mddev), + new_size); + ret = raid5_set_cache_size(mddev, new_size); + if (conf->min_nr_stripes <= new_size / 2) { + pr_err("md/raid:%s: Cannot increase cache size, ret=%d, new_size=%d, min_nr_stripes=%d, max_nr_stripes=%d\n", + mdname(mddev), + ret, + new_size, + conf->min_nr_stripes, + conf->max_nr_stripes); + return -ENOMEM; + } + sh = r5c_recovery_alloc_stripe( + conf, stripe_sect, 0); + } + 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 (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) { + if (!test_bit(STRIPE_R5C_CACHING, &sh->state) && + test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags)) { + r5l_recovery_replay_one_stripe(conf, sh, ctx); + list_move_tail(&sh->lru, cached_stripe_list); + } + r5l_recovery_load_data(log, sh, ctx, payload, + log_offset); + } else if (le16_to_cpu(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 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); + } + } +} + +/* + * 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; + 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(sh, &ctx->cached_list, lru) { + WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state)); + r5c_recovery_load_one_stripe(log, 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 + 10000 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+10001 + * + * 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+10000+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+10000+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; + sector_t next_checkpoint = MaxSector; + + 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; + } + + WARN_ON(list_empty(&ctx->cached_list)); + + 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 = r5l_ring_add(log, 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 = cpu_to_le32(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 = cpu_to_le32(crc32c_le(log->uuid_checksum, + mb, PAGE_SIZE)); + sync_page_io(log->rdev, ctx->pos, PAGE_SIZE, page, + REQ_OP_WRITE, REQ_SYNC | REQ_FUA, false); + sh->log_start = ctx->pos; + list_add_tail(&sh->r5c, &log->stripe_in_journal_list); + atomic_inc(&log->stripe_in_journal_count); + ctx->pos = write_pos; + ctx->seq += 1; + next_checkpoint = sh->log_start; + } + log->next_checkpoint = next_checkpoint; + __free_page(page); + return 0; +} + +static void r5c_recovery_flush_data_only_stripes(struct r5l_log *log, + struct r5l_recovery_ctx *ctx) +{ + struct mddev *mddev = log->rdev->mddev; + struct r5conf *conf = mddev->private; + struct stripe_head *sh, *next; + bool cleared_pending = false; + + if (ctx->data_only_stripes == 0) + return; + + if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) { + cleared_pending = true; + clear_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags); + } + log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_BACK; + + list_for_each_entry_safe(sh, next, &ctx->cached_list, lru) { + r5c_make_stripe_write_out(sh); + set_bit(STRIPE_HANDLE, &sh->state); + list_del_init(&sh->lru); + raid5_release_stripe(sh); + } + + /* reuse conf->wait_for_quiescent in recovery */ + wait_event(conf->wait_for_quiescent, + atomic_read(&conf->active_stripes) == 0); + + log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH; + if (cleared_pending) + set_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags); +} + +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; + + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return -ENOMEM; + + ctx->pos = log->last_checkpoint; + ctx->seq = log->last_cp_seq; + INIT_LIST_HEAD(&ctx->cached_list); + ctx->meta_page = alloc_page(GFP_KERNEL); + + if (!ctx->meta_page) { + ret = -ENOMEM; + goto meta_page; + } + + if (r5l_recovery_allocate_ra_pool(log, ctx) != 0) { + ret = -ENOMEM; + goto ra_pool; + } + + ret = r5c_recovery_flush_log(log, ctx); + + if (ret) + goto error; + + pos = ctx->pos; + ctx->seq += 10000; + + if ((ctx->data_only_stripes == 0) && (ctx->data_parity_stripes == 0)) + pr_info("md/raid:%s: starting from clean shutdown\n", + mdname(mddev)); + else + pr_info("md/raid:%s: recovering %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) { + 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 if (r5c_recovery_rewrite_data_only_stripes(log, ctx)) { + pr_err("md/raid:%s: failed to rewrite stripes to journal\n", + mdname(mddev)); + ret = -EIO; + goto error; + } + + log->log_start = ctx->pos; + log->seq = ctx->seq; + log->last_checkpoint = pos; + r5l_write_super(log, pos); + + r5c_recovery_flush_data_only_stripes(log, ctx); + ret = 0; +error: + r5l_recovery_free_ra_pool(log, ctx); +ra_pool: + __free_page(ctx->meta_page); +meta_page: + kfree(ctx); + return ret; +} + +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_SB_CHANGE_DEVS, &mddev->sb_flags); +} + +static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page) +{ + struct r5conf *conf; + int ret; + + spin_lock(&mddev->lock); + conf = mddev->private; + if (!conf || !conf->log) { + spin_unlock(&mddev->lock); + return 0; + } + + switch (conf->log->r5c_journal_mode) { + case R5C_JOURNAL_MODE_WRITE_THROUGH: + ret = snprintf( + page, PAGE_SIZE, "[%s] %s\n", + r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_THROUGH], + r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_BACK]); + break; + case R5C_JOURNAL_MODE_WRITE_BACK: + ret = snprintf( + page, PAGE_SIZE, "%s [%s]\n", + r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_THROUGH], + r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_BACK]); + break; + default: + ret = 0; + } + spin_unlock(&mddev->lock); + return ret; +} + +/* + * Set journal cache mode on @mddev (external API initially needed by dm-raid). + * + * @mode as defined in 'enum r5c_journal_mode'. + * + */ +int r5c_journal_mode_set(struct mddev *mddev, int mode) +{ + struct r5conf *conf; + + if (mode < R5C_JOURNAL_MODE_WRITE_THROUGH || + mode > R5C_JOURNAL_MODE_WRITE_BACK) + return -EINVAL; + + conf = mddev->private; + if (!conf || !conf->log) + return -ENODEV; + + if (raid5_calc_degraded(conf) > 0 && + mode == R5C_JOURNAL_MODE_WRITE_BACK) + return -EINVAL; + + mddev_suspend(mddev); + conf->log->r5c_journal_mode = mode; + mddev_resume(mddev); + + pr_debug("md/raid:%s: setting r5c cache mode to %d: %s\n", + mdname(mddev), mode, r5c_journal_mode_str[mode]); + return 0; +} +EXPORT_SYMBOL(r5c_journal_mode_set); + +static ssize_t r5c_journal_mode_store(struct mddev *mddev, + const char *page, size_t length) +{ + int mode = ARRAY_SIZE(r5c_journal_mode_str); + size_t len = length; + int ret; + + if (len < 2) + return -EINVAL; + + if (page[len - 1] == '\n') + len--; + + while (mode--) + if (strlen(r5c_journal_mode_str[mode]) == len && + !strncmp(page, r5c_journal_mode_str[mode], len)) + break; + ret = mddev_lock(mddev); + if (ret) + return ret; + ret = r5c_journal_mode_set(mddev, mode); + mddev_unlock(mddev); + return ret ?: length; +} + +struct md_sysfs_entry +r5c_journal_mode = __ATTR(journal_mode, 0644, + r5c_journal_mode_show, r5c_journal_mode_store); + +/* + * Try handle write operation in caching phase. This function should only + * be called in write-back mode. + * + * If all outstanding writes can be handled in caching phase, returns 0 + * If writes requires write-out phase, call r5c_make_stripe_write_out() + * and returns -EAGAIN + */ +int r5c_try_caching_write(struct r5conf *conf, + struct stripe_head *sh, + struct stripe_head_state *s, + int disks) +{ + struct r5l_log *log = conf->log; + int i; + struct r5dev *dev; + int to_cache = 0; + void **pslot; + sector_t tree_index; + int ret; + uintptr_t refcount; + + BUG_ON(!r5c_is_writeback(log)); + + if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) { + /* + * There are two different scenarios here: + * 1. The stripe has some data cached, and it is sent to + * write-out phase for reclaim + * 2. The stripe is clean, and this is the first write + * + * For 1, return -EAGAIN, so we continue with + * handle_stripe_dirtying(). + * + * For 2, set STRIPE_R5C_CACHING and continue with caching + * write. + */ + + /* case 1: anything injournal or anything in written */ + if (s->injournal > 0 || s->written > 0) + return -EAGAIN; + /* case 2 */ + set_bit(STRIPE_R5C_CACHING, &sh->state); + } + + /* + * When run in degraded mode, array is set to write-through mode. + * This check helps drain pending write safely in the transition to + * write-through mode. + * + * When a stripe is syncing, the write is also handled in write + * through mode. + */ + if (s->failed || test_bit(STRIPE_SYNCING, &sh->state)) { + r5c_make_stripe_write_out(sh); + return -EAGAIN; + } + + for (i = disks; i--; ) { + dev = &sh->dev[i]; + /* if non-overwrite, use writing-out phase */ + if (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags) && + !test_bit(R5_InJournal, &dev->flags)) { + r5c_make_stripe_write_out(sh); + return -EAGAIN; + } + } + + /* if the stripe is not counted in big_stripe_tree, add it now */ + if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) && + !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) { + tree_index = r5c_tree_index(conf, sh->sector); + spin_lock(&log->tree_lock); + pslot = radix_tree_lookup_slot(&log->big_stripe_tree, + tree_index); + if (pslot) { + refcount = (uintptr_t)radix_tree_deref_slot_protected( + pslot, &log->tree_lock) >> + R5C_RADIX_COUNT_SHIFT; + radix_tree_replace_slot( + &log->big_stripe_tree, pslot, + (void *)((refcount + 1) << R5C_RADIX_COUNT_SHIFT)); + } else { + /* + * this radix_tree_insert can fail safely, so no + * need to call radix_tree_preload() + */ + ret = radix_tree_insert( + &log->big_stripe_tree, tree_index, + (void *)(1 << R5C_RADIX_COUNT_SHIFT)); + if (ret) { + spin_unlock(&log->tree_lock); + r5c_make_stripe_write_out(sh); + return -EAGAIN; + } + } + spin_unlock(&log->tree_lock); + + /* + * set STRIPE_R5C_PARTIAL_STRIPE, this shows the stripe is + * counted in the radix tree + */ + set_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state); + atomic_inc(&conf->r5c_cached_partial_stripes); + } + + for (i = disks; i--; ) { + dev = &sh->dev[i]; + if (dev->towrite) { + set_bit(R5_Wantwrite, &dev->flags); + set_bit(R5_Wantdrain, &dev->flags); + set_bit(R5_LOCKED, &dev->flags); + to_cache++; + } + } + + if (to_cache) { + set_bit(STRIPE_OP_BIODRAIN, &s->ops_request); + /* + * set STRIPE_LOG_TRAPPED, which triggers r5c_cache_data() + * in ops_run_io(). STRIPE_LOG_TRAPPED will be cleared in + * r5c_handle_data_cached() + */ + set_bit(STRIPE_LOG_TRAPPED, &sh->state); + } + + return 0; +} + +/* + * free extra pages (orig_page) we allocated for prexor + */ +void r5c_release_extra_page(struct stripe_head *sh) +{ + struct r5conf *conf = sh->raid_conf; + int i; + bool using_disk_info_extra_page; + + using_disk_info_extra_page = + sh->dev[0].orig_page == conf->disks[0].extra_page; + + for (i = sh->disks; i--; ) + if (sh->dev[i].page != sh->dev[i].orig_page) { + struct page *p = sh->dev[i].orig_page; + + sh->dev[i].orig_page = sh->dev[i].page; + clear_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags); + + if (!using_disk_info_extra_page) + put_page(p); + } + + if (using_disk_info_extra_page) { + clear_bit(R5C_EXTRA_PAGE_IN_USE, &conf->cache_state); + md_wakeup_thread(conf->mddev->thread); + } +} + +void r5c_use_extra_page(struct stripe_head *sh) +{ + struct r5conf *conf = sh->raid_conf; + int i; + struct r5dev *dev; + + for (i = sh->disks; i--; ) { + dev = &sh->dev[i]; + if (dev->orig_page != dev->page) + put_page(dev->orig_page); + dev->orig_page = conf->disks[i].extra_page; + } +} + +/* + * clean up the stripe (clear R5_InJournal for dev[pd_idx] etc.) after the + * stripe is committed to RAID disks. + */ +void r5c_finish_stripe_write_out(struct r5conf *conf, + struct stripe_head *sh, + struct stripe_head_state *s) +{ + struct r5l_log *log = conf->log; + int i; + int do_wakeup = 0; + sector_t tree_index; + void **pslot; + uintptr_t refcount; + + if (!log || !test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags)) + return; + + WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state)); + clear_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags); + + if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) + return; + + for (i = sh->disks; i--; ) { + clear_bit(R5_InJournal, &sh->dev[i].flags); + if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) + do_wakeup = 1; + } + + /* + * analyse_stripe() runs before r5c_finish_stripe_write_out(), + * We updated R5_InJournal, so we also update s->injournal. + */ + s->injournal = 0; + + if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state)) + if (atomic_dec_and_test(&conf->pending_full_writes)) + md_wakeup_thread(conf->mddev->thread); + + if (do_wakeup) + wake_up(&conf->wait_for_overlap); + + spin_lock_irq(&log->stripe_in_journal_lock); + list_del_init(&sh->r5c); + spin_unlock_irq(&log->stripe_in_journal_lock); + sh->log_start = MaxSector; + + atomic_dec(&log->stripe_in_journal_count); + r5c_update_log_state(log); + + /* stop counting this stripe in big_stripe_tree */ + if (test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) || + test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) { + tree_index = r5c_tree_index(conf, sh->sector); + spin_lock(&log->tree_lock); + pslot = radix_tree_lookup_slot(&log->big_stripe_tree, + tree_index); + BUG_ON(pslot == NULL); + refcount = (uintptr_t)radix_tree_deref_slot_protected( + pslot, &log->tree_lock) >> + R5C_RADIX_COUNT_SHIFT; + if (refcount == 1) + radix_tree_delete(&log->big_stripe_tree, tree_index); + else + radix_tree_replace_slot( + &log->big_stripe_tree, pslot, + (void *)((refcount - 1) << R5C_RADIX_COUNT_SHIFT)); + spin_unlock(&log->tree_lock); + } + + if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) { + BUG_ON(atomic_read(&conf->r5c_cached_partial_stripes) == 0); + atomic_dec(&conf->r5c_flushing_partial_stripes); + atomic_dec(&conf->r5c_cached_partial_stripes); + } + + if (test_and_clear_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) { + BUG_ON(atomic_read(&conf->r5c_cached_full_stripes) == 0); + atomic_dec(&conf->r5c_flushing_full_stripes); + atomic_dec(&conf->r5c_cached_full_stripes); + } + + r5l_append_flush_payload(log, sh->sector); + /* stripe is flused to raid disks, we can do resync now */ + if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state)) + set_bit(STRIPE_HANDLE, &sh->state); +} + +int r5c_cache_data(struct r5l_log *log, struct stripe_head *sh) +{ + struct r5conf *conf = sh->raid_conf; + int pages = 0; + int reserve; + int i; + int ret = 0; + + BUG_ON(!log); + + for (i = 0; i < sh->disks; i++) { + void *addr; + + if (!test_bit(R5_Wantwrite, &sh->dev[i].flags)) + continue; + addr = kmap_atomic(sh->dev[i].page); + sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum, + addr, PAGE_SIZE); + kunmap_atomic(addr); + pages++; + } + WARN_ON(pages == 0); + + /* + * The stripe must enter state machine again to call endio, so + * don't delay. + */ + clear_bit(STRIPE_DELAYED, &sh->state); + atomic_inc(&sh->count); + + mutex_lock(&log->io_mutex); + /* meta + data */ + reserve = (1 + pages) << (PAGE_SHIFT - 9); + + if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) && + sh->log_start == MaxSector) + r5l_add_no_space_stripe(log, sh); + else if (!r5l_has_free_space(log, reserve)) { + if (sh->log_start == log->last_checkpoint) + BUG(); + else + r5l_add_no_space_stripe(log, sh); + } else { + ret = r5l_log_stripe(log, sh, pages, 0); + if (ret) { + spin_lock_irq(&log->io_list_lock); + list_add_tail(&sh->log_list, &log->no_mem_stripes); + spin_unlock_irq(&log->io_list_lock); + } + } + + mutex_unlock(&log->io_mutex); + return 0; +} + +/* check whether this big stripe is in write back cache. */ +bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect) +{ + struct r5l_log *log = conf->log; + sector_t tree_index; + void *slot; + + if (!log) + return false; + + WARN_ON_ONCE(!rcu_read_lock_held()); + tree_index = r5c_tree_index(conf, sect); + slot = radix_tree_lookup(&log->big_stripe_tree, tree_index); + return slot != NULL; +} + +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 = 0; + + /* 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, REQ_OP_READ, 0, 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; + r5l_log_write_empty_meta_block(log, cp, log->last_cp_seq); + /* + * 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); + + if (create_super) { + log->log_start = r5l_ring_add(log, cp, BLOCK_SECTORS); + log->seq = log->last_cp_seq + 1; + log->next_checkpoint = cp; + } else + ret = r5l_recovery_log(log); + + r5c_update_log_state(log); + return ret; +ioerr: + __free_page(page); + return ret; +} + +int r5l_start(struct r5l_log *log) +{ + int ret; + + if (!log) + return 0; + + ret = r5l_load_log(log); + if (ret) { + struct mddev *mddev = log->rdev->mddev; + struct r5conf *conf = mddev->private; + + r5l_exit_log(conf); + } + return ret; +} + +void r5c_update_on_rdev_error(struct mddev *mddev, struct md_rdev *rdev) +{ + struct r5conf *conf = mddev->private; + struct r5l_log *log = conf->log; + + if (!log) + return; + + if ((raid5_calc_degraded(conf) > 0 || + test_bit(Journal, &rdev->flags)) && + conf->log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK) + schedule_work(&log->disable_writeback_work); +} + +int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) +{ + struct request_queue *q = bdev_get_queue(rdev->bdev); + struct r5l_log *log; + char b[BDEVNAME_SIZE]; + int ret; + + pr_debug("md/raid:%s: using device %s as journal\n", + mdname(conf->mddev), bdevname(rdev->bdev, b)); + + if (PAGE_SIZE != 4096) + return -EINVAL; + + /* + * The PAGE_SIZE must be big enough to hold 1 r5l_meta_block and + * raid_disks r5l_payload_data_parity. + * + * Write journal and cache does not work for very big array + * (raid_disks > 203) + */ + if (sizeof(struct r5l_meta_block) + + ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32)) * + conf->raid_disks) > PAGE_SIZE) { + pr_err("md/raid:%s: write journal/cache doesn't work for array with %d disks\n", + mdname(conf->mddev), conf->raid_disks); + return -EINVAL; + } + + log = kzalloc(sizeof(*log), GFP_KERNEL); + if (!log) + return -ENOMEM; + log->rdev = rdev; + + log->need_cache_flush = test_bit(QUEUE_FLAG_WC, &q->queue_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, NULL, 0); + + log->io_kc = KMEM_CACHE(r5l_io_unit, 0); + if (!log->io_kc) + goto io_kc; + + ret = mempool_init_slab_pool(&log->io_pool, R5L_POOL_SIZE, log->io_kc); + if (ret) + goto io_pool; + + ret = bioset_init(&log->bs, R5L_POOL_SIZE, 0, BIOSET_NEED_BVECS); + if (ret) + goto io_bs; + + ret = mempool_init_page_pool(&log->meta_pool, R5L_POOL_SIZE, 0); + if (ret) + goto out_mempool; + + spin_lock_init(&log->tree_lock); + INIT_RADIX_TREE(&log->big_stripe_tree, GFP_NOWAIT | __GFP_NOWARN); + + log->reclaim_thread = md_register_thread(r5l_reclaim_thread, + log->rdev->mddev, "reclaim"); + if (!log->reclaim_thread) + goto reclaim_thread; + log->reclaim_thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL; + + init_waitqueue_head(&log->iounit_wait); + + INIT_LIST_HEAD(&log->no_mem_stripes); + + INIT_LIST_HEAD(&log->no_space_stripes); + spin_lock_init(&log->no_space_stripes_lock); + + INIT_WORK(&log->deferred_io_work, r5l_submit_io_async); + INIT_WORK(&log->disable_writeback_work, r5c_disable_writeback_async); + + log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH; + INIT_LIST_HEAD(&log->stripe_in_journal_list); + spin_lock_init(&log->stripe_in_journal_lock); + atomic_set(&log->stripe_in_journal_count, 0); + + rcu_assign_pointer(conf->log, log); + + set_bit(MD_HAS_JOURNAL, &conf->mddev->flags); + return 0; + +reclaim_thread: + mempool_exit(&log->meta_pool); +out_mempool: + bioset_exit(&log->bs); +io_bs: + mempool_exit(&log->io_pool); +io_pool: + kmem_cache_destroy(log->io_kc); +io_kc: + kfree(log); + return -EINVAL; +} + +void r5l_exit_log(struct r5conf *conf) +{ + struct r5l_log *log = conf->log; + + conf->log = NULL; + synchronize_rcu(); + + /* Ensure disable_writeback_work wakes up and exits */ + wake_up(&conf->mddev->sb_wait); + flush_work(&log->disable_writeback_work); + md_unregister_thread(&log->reclaim_thread); + mempool_exit(&log->meta_pool); + bioset_exit(&log->bs); + mempool_exit(&log->io_pool); + kmem_cache_destroy(log->io_kc); + kfree(log); +} |