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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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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 __rcu *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 * doesn'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 voidr5c_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]); } }}
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; struct r5l_log *log = READ_ONCE(conf->log);
if (!r5c_is_writeback(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(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){ struct r5l_log *log = READ_ONCE(conf->log);
if (!r5c_is_writeback(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(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 = READ_ONCE(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 = READ_ONCE(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 = READ_ONCE(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;
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, !READ_ONCE(conf->log) || !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
log = READ_ONCE(conf->log); if (log) { mddev_suspend(mddev, false); log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH; mddev_resume(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(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(log->rdev->bdev, BIO_MAX_VECS, REQ_OP_WRITE, GFP_NOIO, &log->bs);
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_local_page(sh->dev[i].page); sh->dev[i].log_checksum = crc32c(log->uuid_checksum, addr, PAGE_SIZE); kunmap_local(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 = READ_ONCE(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(&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(&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); bio_uninit(bio);
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_init(&log->flush_bio, log->rdev->bdev, NULL, 0, REQ_OP_WRITE | REQ_PREFLUSH); log->flush_bio.bi_end_io = r5l_log_flush_endio; 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 (!bdev_max_discard_sectors(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 waiting * for all IO finish, hence waiting for reclaim thread, while reclaim * thread is calling this function and waiting 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); } else { blkdev_issue_discard(bdev, log->last_checkpoint + log->rdev->data_offset, log->device_size - log->last_checkpoint, GFP_NOIO); blkdev_issue_discard(bdev, log->rdev->data_offset, end, GFP_NOIO); }}
/* * 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 (!READ_ONCE(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 = READ_ONCE(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 = READ_ONCE(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;
target = READ_ONCE(log->reclaim_target); do { if (new < target) return; } while (!try_cmpxchg(&log->reclaim_target, &target, new)); md_wakeup_thread(log->reclaim_thread);}
void r5l_quiesce(struct r5l_log *log, int quiesce){ struct mddev *mddev = log->rdev->mddev; struct md_thread *thread = rcu_dereference_protected( log->reclaim_thread, lockdep_is_held(&mddev->reconfig_mutex));
if (quiesce) { /* make sure r5l_write_super_and_discard_space exits */ wake_up(&mddev->sb_wait); kthread_park(thread->tsk); r5l_wake_reclaim(log, MaxSector); r5l_do_reclaim(log); } else kthread_unpark(thread->tsk);}
bool r5l_log_disk_error(struct r5conf *conf){ struct r5l_log *log = READ_ONCE(conf->log);
/* don't allow write if journal disk is missing */ if (!log) return test_bit(MD_HAS_JOURNAL, &conf->mddev->flags); else return test_bit(Faulty, &log->rdev->flags);}
#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]; struct bio_vec ra_bvec[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 */};
static int r5l_recovery_allocate_ra_pool(struct r5l_log *log, struct r5l_recovery_ctx *ctx){ struct page *page;
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) 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]);}
/* * 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){ struct bio bio; int ret;
bio_init(&bio, log->rdev->bdev, ctx->ra_bvec, R5L_RECOVERY_PAGE_POOL_SIZE, REQ_OP_READ); 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(&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; }
ret = submit_bio_wait(&bio); bio_uninit(&bio); return ret;}
/* * 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(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 voidr5l_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(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 voidr5l_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 */ rdev = conf->disks[disk_index].rdev; if (rdev) { atomic_inc(&rdev->nr_pending); sync_page_io(rdev, sh->sector, PAGE_SIZE, sh->dev[disk_index].page, REQ_OP_WRITE, false); rdev_dec_pending(rdev, rdev->mddev); } rrdev = conf->disks[disk_index].replacement; if (rrdev) { atomic_inc(&rrdev->nr_pending); sync_page_io(rrdev, sh->sector, PAGE_SIZE, sh->dev[disk_index].page, REQ_OP_WRITE, false); rdev_dec_pending(rrdev, rrdev->mddev); } } 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, NULL, stripe_sect, noblock ? R5_GAS_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 voidr5c_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 voidr5c_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 intr5l_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_local_page(page); checksum = crc32c(log->uuid_checksum, addr, PAGE_SIZE); kunmap_local(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 intr5l_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)) { sector_t payload_len;
payload = (void *)mb + mb_offset; payload_flush = (void *)mb + mb_offset;
if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) { payload_len = sizeof(struct r5l_payload_data_parity) + (sector_t)sizeof(__le32) * (le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9)); if (mb_offset + payload_len > le32_to_cpu(mb->meta_size)) goto mismatch; 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) { payload_len = sizeof(struct r5l_payload_data_parity) + (sector_t)sizeof(__le32) * (le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9)); if (mb_offset + payload_len > le32_to_cpu(mb->meta_size)) goto mismatch; 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) { payload_len = sizeof(struct r5l_payload_flush) + (sector_t)le32_to_cpu(payload_flush->size); if (mb_offset + payload_len > le32_to_cpu(mb->meta_size)) goto mismatch; } else /* not R5LOG_PAYLOAD_DATA/PARITY/FLUSH */ goto mismatch;
if (le16_to_cpu(payload->header.type) != R5LOG_PAYLOAD_FLUSH) { log_offset = r5l_ring_add(log, log_offset, le32_to_cpu(payload->size)); } mb_offset += payload_len; }
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 intr5c_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)) { sector_t payload_len; 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;
payload_len = sizeof(struct r5l_payload_flush) + (sector_t)le32_to_cpu(payload_flush->size); if (mb_offset + payload_len > le32_to_cpu(mb->meta_size)) return -EINVAL;
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 += payload_len; continue; }
/* DATA or PARITY payload */ payload_len = sizeof(struct r5l_payload_data_parity) + (sector_t)sizeof(__le32) * (le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9)); if (mb_offset + payload_len > le32_to_cpu(mb->meta_size)) return -EINVAL;
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 += payload_len; }
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 intr5c_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_local_page(dev->page); payload->checksum[0] = cpu_to_le32( crc32c(log->uuid_checksum, addr, PAGE_SIZE)); kunmap_local(addr); sync_page_io(log->rdev, write_pos, PAGE_SIZE, dev->page, REQ_OP_WRITE, 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(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_obj(*ctx); 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;
ret = mddev_lock(mddev); if (ret) return ret;
conf = mddev->private; if (!conf || !conf->log) goto out_unlock;
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; }
out_unlock: mddev_unlock(mddev); 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;
conf->log->r5c_journal_mode = mode;
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_suspend_and_lock(mddev); if (ret) return ret; ret = r5c_journal_mode_set(mddev, mode); mddev_unlock_and_resume(mddev); return ret ?: length;}
struct md_sysfs_entryr5c_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 = READ_ONCE(conf->log); int i; struct r5dev *dev; int to_cache = 0; void __rcu **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 = READ_ONCE(conf->log); int i; sector_t tree_index; void __rcu **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)) wake_up_bit(&sh->dev[i].flags, R5_Overlap); }
/* * 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);
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_local_page(sh->dev[i].page); sh->dev[i].log_checksum = crc32c(log->uuid_checksum, addr, PAGE_SIZE); kunmap_local(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 = READ_ONCE(conf->log); sector_t tree_index; void *slot;
if (!log) return false;
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, 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(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 = get_random_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 = READ_ONCE(conf->log);
if (!log) return;
if ((raid5_calc_degraded(conf) > 0 || test_bit(Journal, &rdev->flags)) && 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 r5l_log *log; struct md_thread *thread; int ret;
pr_debug("md/raid:%s: using device %pg as journal\n", mdname(conf->mddev), rdev->bdev);
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_obj(*log); if (!log) return -ENOMEM; log->rdev = rdev; log->need_cache_flush = bdev_write_cache(rdev->bdev); log->uuid_checksum = crc32c(~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);
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);
thread = md_register_thread(r5l_reclaim_thread, log->rdev->mddev, "reclaim"); if (!thread) goto reclaim_thread;
thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL; rcu_assign_pointer(log->reclaim_thread, thread);
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);
WRITE_ONCE(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;
md_unregister_thread(conf->mddev, &log->reclaim_thread);
/* * 'reconfig_mutex' is held by caller, set 'confg->log' to NULL to * ensure disable_writeback_work wakes up and exits. */ WRITE_ONCE(conf->log, NULL); wake_up(&conf->mddev->sb_wait); flush_work(&log->disable_writeback_work);
mempool_exit(&log->meta_pool); bioset_exit(&log->bs); mempool_exit(&log->io_pool); kmem_cache_destroy(log->io_kc); kfree(log);}