cregit-Linux how code gets into the kernel

Release 4.7 drivers/md/raid5-cache.c

Directory: drivers/md
/*
 * Copyright (C) 2015 Shaohua Li <shli@fb.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 */
#include <linux/kernel.h>
#include <linux/wait.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/raid/md_p.h>
#include <linux/crc32c.h>
#include <linux/random.h>
#include "md.h"
#include "raid5.h"

/*
 * metadata/data stored in disk with 4k size unit (a block) regardless
 * underneath hardware sector size. only works with PAGE_SIZE == 4096
 */

#define BLOCK_SECTORS (8)

/*
 * reclaim runs every 1/4 disk size or 10G reclaimable space. This can prevent
 * recovery scans a very long log
 */

#define RECLAIM_MAX_FREE_SPACE (10 * 1024 * 1024 * 2) 
/* sector */

#define RECLAIM_MAX_FREE_SPACE_SHIFT (2)

/*
 * 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


struct r5l_log {
	
struct md_rdev *rdev;

	
u32 uuid_checksum;

	
sector_t device_size;		/* log device size, round to
                                         * BLOCK_SECTORS */
	
sector_t max_free_space;	/* reclaim run if free space is at
                                         * this size */

	
sector_t last_checkpoint;	/* log tail. where recovery scan
                                         * starts from */
	
u64 last_cp_seq;		/* log tail sequence */

	
sector_t log_start;		/* log head. where new data appends */
	
u64 seq;			/* log head sequence */

	
sector_t next_checkpoint;
	
u64 next_cp_seq;

	
struct mutex io_mutex;
	
struct r5l_io_unit *current_io;	/* current io_unit accepting new data */

	
spinlock_t io_list_lock;
	
struct list_head running_ios;	/* io_units which are still running,
                                         * and have not yet been completely
                                         * written to the log */
	
struct list_head io_end_ios;	/* io_units which have been completely
                                         * written to the log but not yet written
                                         * to the RAID */
	
struct list_head flushing_ios;	/* io_units which are waiting for log
                                         * cache flush */
	
struct list_head finished_ios;	/* io_units which settle down in log disk */
	
struct bio flush_bio;

	
struct 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;
	
bool in_teardown;
};

/*
 * an IO range starts from a meta data block and end at the next meta data
 * block. The io unit's the meta data block tracks data/parity followed it. io
 * unit is written to log disk with normal write, as we always flush log disk
 * first and then start move data to raid disks, there is no requirement to
 * write io unit with FLUSH/FUA
 */

struct r5l_io_unit {
	
struct r5l_log *log;

	
struct page *meta_page;	/* store meta block */
	
int meta_offset;	/* current offset in meta_page */

	
struct bio *current_bio;/* current_bio accepting new data */

	
atomic_t pending_stripe;/* how many stripes not flushed to raid */
	
u64 seq;		/* seq number of the metablock */
	
sector_t log_start;	/* where the io_unit starts */
	
sector_t log_end;	/* where the io_unit ends */
	
struct list_head log_sibling; /* log->running_ios */
	
struct list_head stripe_list; /* stripes added to the io_unit */

	
int state;
	
bool need_split_bio;
};

/* r5l_io_unit state */

enum r5l_io_unit_state {
	
IO_UNIT_RUNNING = 0,	/* accepting new IO */
	
IO_UNIT_IO_START = 1,	/* io_unit bio start writing to log,
                                 * don't accepting new bio */
	
IO_UNIT_IO_END = 2,	/* io_unit bio finish writing to log */
	
IO_UNIT_STRIPE_END = 3,	/* stripes data finished writing to raid */
};


static sector_t r5l_ring_add(struct r5l_log *log, sector_t start, sector_t inc) { start += inc; if (start >= log->device_size) start = start - log->device_size; return start; }

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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; }

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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; }

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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; }

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static void r5l_io_run_stripes(struct r5l_io_unit *io) { struct stripe_head *sh, *next; list_for_each_entry_safe(sh, next, &io->stripe_list, log_list) { list_del_init(&sh->log_list); set_bit(STRIPE_HANDLE, &sh->state); raid5_release_stripe(sh); } }

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static void r5l_log_run_stripes(struct r5l_log *log) { struct r5l_io_unit *io, *next; assert_spin_locked(&log->io_list_lock); list_for_each_entry_safe(io, next, &log->running_ios, log_sibling) { /* don't change list order */ if (io->state < IO_UNIT_IO_END) break; list_move_tail(&io->log_sibling, &log->finished_ios); r5l_io_run_stripes(io); } }

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static void r5l_move_to_end_ios(struct r5l_log *log) { struct r5l_io_unit *io, *next; assert_spin_locked(&log->io_list_lock); list_for_each_entry_safe(io, next, &log->running_ios, log_sibling) { /* don't change list order */ if (io->state < IO_UNIT_IO_END) break; list_move_tail(&io->log_sibling, &log->io_end_ios); } }

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static void r5l_log_endio(struct bio *bio) { struct r5l_io_unit *io = bio->bi_private; struct r5l_log *log = io->log; unsigned long flags; if (bio->bi_error) md_error(log->rdev->mddev, log->rdev); bio_put(bio); 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 (log->need_cache_flush) r5l_move_to_end_ios(log); else r5l_log_run_stripes(log); spin_unlock_irqrestore(&log->io_list_lock, flags); if (log->need_cache_flush) md_wakeup_thread(log->rdev->mddev->thread); }

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static void r5l_submit_current_io(struct r5l_log *log) { struct r5l_io_unit *io = log->current_io; struct r5l_meta_block *block; unsigned long flags; u32 crc; if (!io) return; block = page_address(io->meta_page); block->meta_size = cpu_to_le32(io->meta_offset); crc = crc32c_le(log->uuid_checksum, block, PAGE_SIZE); block->checksum = cpu_to_le32(crc); log->current_io = NULL; spin_lock_irqsave(&log->io_list_lock, flags); __r5l_set_io_unit_state(io, IO_UNIT_IO_START); spin_unlock_irqrestore(&log->io_list_lock, flags); submit_bio(WRITE, io->current_bio); }

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static struct bio *r5l_bio_alloc(struct r5l_log *log) { struct bio *bio = bio_alloc_bioset(GFP_NOIO, BIO_MAX_PAGES, log->bs); bio->bi_rw = WRITE; bio->bi_bdev = log->rdev->bdev; bio->bi_iter.bi_sector = log->rdev->data_offset + log->log_start; return bio; }

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static void r5_reserve_log_entry(struct r5l_log *log, struct r5l_io_unit *io) { log->log_start = r5l_ring_add(log, log->log_start, BLOCK_SECTORS); /* * If we filled up the log device start from the beginning again, * which will require a new bio. * * Note: for this to work properly the log size needs to me a multiple * of BLOCK_SECTORS. */ if (log->log_start == 0) io->need_split_bio = true; io->log_end = log->log_start; }

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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); 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; }

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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; }

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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); }

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static void r5l_append_payload_page(struct r5l_log *log, struct page *page) { struct r5l_io_unit *io = log->current_io; if (io->need_split_bio) { struct bio *prev = io->current_bio; io->current_bio = r5l_bio_alloc(log); bio_chain(io->current_bio, prev); submit_bio(WRITE, prev); } if (!bio_add_page(io->current_bio, page, PAGE_SIZE, 0)) BUG(); r5_reserve_log_entry(log, io); }

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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; for (i = 0; i < sh->disks; i++) { if (!test_bit(R5_Wantwrite, &sh->dev[i].flags)) continue; if (i == sh->pd_idx || i == sh->qd_idx) continue; r5l_append_payload_meta(log, R5LOG_PAYLOAD_DATA, raid5_compute_blocknr(sh, i, 0), sh->dev[i].log_checksum, 0, false); r5l_append_payload_page(log, sh->dev[i].page); } if (sh->qd_idx >= 0) { r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY, sh->sector, sh->dev[sh->pd_idx].log_checksum, sh->dev[sh->qd_idx].log_checksum, true); r5l_append_payload_page(log, sh->dev[sh->pd_idx].page); r5l_append_payload_page(log, sh->dev[sh->qd_idx].page); } else { r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY, sh->sector, sh->dev[sh->pd_idx].log_checksum, 0, false); r5l_append_payload_page(log, sh->dev[sh->pd_idx].page); } list_add_tail(&sh->log_list, &io->stripe_list); atomic_inc(&io->pending_stripe); sh->log_io = io; return 0; }

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static void r5l_wake_reclaim(struct r5l_log *log, sector_t space); /* * running in raid5d, where reclaim could wait for raid5d too (when it flushes * data from log to raid disks), so we shouldn't wait for reclaim here */
int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh) { int write_disks = 0; int data_pages, parity_pages; int meta_size; int reserve; int i; int ret = 0; if (!log) return -EAGAIN; /* Don't support stripe batch */ if (sh->log_io || !test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags) || test_bit(STRIPE_SYNCING, &sh->state)) { /* the stripe is written to log, we start writing it to raid */ clear_bit(STRIPE_LOG_TRAPPED, &sh->state); return -EAGAIN; } for (i = 0; i < sh->disks; i++) { void *addr; if (!test_bit(R5_Wantwrite, &sh->dev[i].flags)) continue; write_disks++; /* checksum is already calculated in last run */ if (test_bit(STRIPE_LOG_TRAPPED, &sh->state)) continue; addr = kmap_atomic(sh->dev[i].page); sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum, addr, PAGE_SIZE); kunmap_atomic(addr); } parity_pages = 1 + !!(sh->qd_idx >= 0); data_pages = write_disks - parity_pages; meta_size = ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32)) * data_pages) + sizeof(struct r5l_payload_data_parity) + sizeof(__le32) * parity_pages; /* Doesn't work with very big raid array */ if (meta_size + sizeof(struct r5l_meta_block) > PAGE_SIZE) return -EINVAL; set_bit(STRIPE_LOG_TRAPPED, &sh->state); /* * The stripe must enter state machine again to finish the write, so * don't delay. */ clear_bit(STRIPE_DELAYED, &sh->state); atomic_inc(&sh->count); mutex_lock(&log->io_mutex); /* meta + data */ reserve = (1 + write_disks) << (PAGE_SHIFT - 9); if (!r5l_has_free_space(log, reserve)) { spin_lock(&log->no_space_stripes_lock); list_add_tail(&sh->log_list, &log->no_space_stripes); spin_unlock(&log->no_space_stripes_lock); r5l_wake_reclaim(log, reserve); } 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); return 0; }

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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); }

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int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio) { if (!log) return -ENODEV; /* * we flush log disk cache first, then write stripe data to raid disks. * So if bio is finished, the log disk cache is flushed already. The * recovery guarantees we can recovery the bio from log disk, so we * don't need to flush again */ if (bio->bi_iter.bi_size == 0) { bio_endio(bio); return 0; } bio->bi_rw &= ~REQ_FLUSH; return -EAGAIN; }

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/* 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); }

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static sector_t r5l_reclaimable_space(struct r5l_log *log) { return r5l_ring_distance(log, log->last_checkpoint, log->next_checkpoint); }

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static void r5l_run_no_mem_stripe(struct r5l_log *log) { struct stripe_head *sh; assert_spin_locked(&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); } }

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static bool r5l_complete_finished_ios(struct r5l_log *log) { struct r5l_io_unit *io, *next; bool found = false; assert_spin_locked(&log->io_list_lock); list_for_each_entry_safe(io, next, &log->finished_ios, log_sibling) { /* don't change list order */ if (io->state < IO_UNIT_STRIPE_END) break; log->next_checkpoint = io->log_start; log->next_cp_seq = io->seq; list_del(&io->log_sibling); mempool_free(io, log->io_pool); r5l_run_no_mem_stripe(log); found = true; } return found; }

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static void __r5l_stripe_write_finished(struct r5l_io_unit *io) { struct r5l_log *log = io->log; unsigned long flags; spin_lock_irqsave(&log->io_list_lock, flags); __r5l_set_io_unit_state(io, IO_UNIT_STRIPE_END); if (!r5l_complete_finished_ios(log)) { spin_unlock_irqrestore(&log->io_list_lock, flags); return; } if (r5l_reclaimable_space(log) > log->max_free_space) r5l_wake_reclaim(log, 0); spin_unlock_irqrestore(&log->io_list_lock, flags); wake_up(&log->iounit_wait); }

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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); }

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static void r5l_log_flush_endio(struct bio *bio) { struct r5l_log *log = container_of(bio, struct r5l_log, flush_bio); unsigned long flags; struct r5l_io_unit *io; if (bio->bi_error) md_error(log->rdev->mddev, log->rdev); spin_lock_irqsave(&log->io_list_lock, flags); list_for_each_entry(io, &log->flushing_ios, log_sibling) r5l_io_run_stripes(io); list_splice_tail_init(&log->flushing_ios, &log->finished_ios); spin_unlock_irqrestore(&log->io_list_lock, flags); }

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/* * Starting dispatch IO to raid. * io_unit(meta) consists of a log. There is one situation we want to avoid. A * broken meta in the middle of a log causes recovery can't find meta at the * head of log. If operations require meta at the head persistent in log, we * must make sure meta before it persistent in log too. A case is: * * stripe data/parity is in log, we start write stripe to raid disks. stripe * data/parity must be persistent in log before we do the write to raid disks. * * The solution is we restrictly maintain io_unit list order. In this case, we * only write stripes of an io_unit to raid disks till the io_unit is the first * one whose data/parity is in log. */
void r5l_flush_stripe_to_raid(struct r5l_log *log) { bool do_flush; if (!log || !log->need_cache_flush) return; spin_lock_irq(&log->io_list_lock); /* flush bio is running */ if (!list_empty(&log->flushing_ios)) { spin_unlock_irq(&log->io_list_lock); return; } list_splice_tail_init(&log->io_end_ios, &log->flushing_ios); do_flush = !list_empty(&log->flushing_ios); spin_unlock_irq(&log->io_list_lock); if (!do_flush) return; bio_reset(&log->flush_bio); log->flush_bio.bi_bdev = log->rdev->bdev; log->flush_bio.bi_end_io = r5l_log_flush_endio; submit_bio(WRITE_FLUSH, &log->flush_bio); }

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static void r5l_write_super(struct r5l_log *log, sector_t cp);
static void r5l_write_super_and_discard_space(struct r5l_log *log, sector_t end) { struct block_device *bdev = log->rdev->bdev; struct mddev *mddev; r5l_write_super(log, end); if (!blk_queue_discard(bdev_get_queue(bdev))) return; mddev = log->rdev->mddev; /* * This is to avoid a deadlock. r5l_quiesce holds reconfig_mutex and * wait for this thread to finish. This thread waits for * MD_CHANGE_PENDING clear, which is supposed to be done in * md_check_recovery(). md_check_recovery() tries to get * reconfig_mutex. Since r5l_quiesce already holds the mutex, * md_check_recovery() fails, so the PENDING never get cleared. The * in_teardown check workaround this issue. */ if (!log->in_teardown) { set_mask_bits(&mddev->flags, 0, BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING)); md_wakeup_thread(mddev->thread); wait_event(mddev->sb_wait, !test_bit(MD_CHANGE_PENDING, &mddev->flags) || log->in_teardown); /* * r5l_quiesce could run after in_teardown check and hold * mutex first. Superblock might get updated twice. */ if (log->in_teardown) md_update_sb(mddev, 1); } else { WARN_ON(!mddev_is_locked(mddev)); md_update_sb(mddev, 1); } /* discard IO error really doesn't matter, ignore it */ if (log->last_checkpoint < end) { blkdev_issue_discard(bdev, log->last_checkpoint + log->rdev->data_offset, end - log->last_checkpoint, GFP_NOIO, 0); } else { blkdev_issue_discard(bdev, log->last_checkpoint + log->rdev->data_offset, log->device_size - log->last_checkpoint, GFP_NOIO, 0); blkdev_issue_discard(bdev, log->rdev->data_offset, end, GFP_NOIO, 0); } }

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shaohua lishaohua li22295.69%266.67%
guoqing jiangguoqing jiang104.31%133.33%
Total232100.00%3100.00%


static void r5l_do_reclaim(struct r5l_log *log) { sector_t reclaim_target = xchg(&log->reclaim_target, 0); sector_t reclaimable; sector_t next_checkpoint; u64 next_cp_seq; spin_lock_irq(&log->io_list_lock); /* * move proper io_unit to reclaim list. We should not change the order. * reclaimable/unreclaimable io_unit can be mixed in the list, we * shouldn't reuse space of an unreclaimable io_unit */ while (1) { reclaimable = r5l_reclaimable_space(log); if (reclaimable >= reclaim_target || (list_empty(&log->running_ios) && list_empty(&log->io_end_ios) && list_empty(&log->flushing_ios) && list_empty(&log->finished_ios))) break; md_wakeup_thread(log->rdev->mddev->thread); wait_event_lock_irq(log->iounit_wait, r5l_reclaimable_space(log) > reclaimable, log->io_list_lock); } next_checkpoint = log->next_checkpoint; next_cp_seq = log->next_cp_seq; spin_unlock_irq(&log->io_list_lock); BUG_ON(reclaimable < 0); if (reclaimable == 0) return; /* * write_super will flush cache of each raid disk. We must write super * here, because the log area might be reused soon and we don't want to * confuse recovery */ r5l_write_super_and_discard_space(log, next_checkpoint); mutex_lock(&log->io_mutex); log->last_checkpoint = next_checkpoint; log->last_cp_seq = next_cp_seq; mutex_unlock(&log->io_mutex); r5l_run_no_space_stripes(log); }

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shaohua lishaohua li15276.00%360.00%
christoph hellwigchristoph hellwig4824.00%240.00%
Total200100.00%5100.00%


static void r5l_reclaim_thread(struct md_thread *thread) { struct mddev *mddev = thread->mddev; struct r5conf *conf = mddev->private; struct r5l_log *log = conf->log; if (!log) return; r5l_do_reclaim(log); }

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shaohua lishaohua li49100.00%1100.00%
Total49100.00%1100.00%


static void r5l_wake_reclaim(struct r5l_log *log, sector_t space) { unsigned long target; unsigned long new = (unsigned long)space; /* overflow in theory */ do { target = log->reclaim_target; if (new < target) return; } while (cmpxchg(&log->reclaim_target, target, new) != target); md_wakeup_thread(log->reclaim_thread); }

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shaohua lishaohua li69100.00%1100.00%
Total69100.00%1100.00%


void r5l_quiesce(struct r5l_log *log, int state) { struct mddev *mddev; if (!log || state == 2) return; if (state == 0) { log->in_teardown = 0; /* * This is a special case for hotadd. In suspend, the array has * no journal. In resume, journal is initialized as well as the * reclaim thread. */ if (log->reclaim_thread) return; log->reclaim_thread = md_register_thread(r5l_reclaim_thread, log->rdev->mddev, "reclaim"); } else if (state == 1) { /* * at this point all stripes are finished, so io_unit is at * least in STRIPE_END state */ log->in_teardown = 1; /* make sure r5l_write_super_and_discard_space exits */ mddev = log->rdev->mddev; wake_up(&mddev->sb_wait); r5l_wake_reclaim(log, -1L); md_unregister_thread(&log->reclaim_thread); r5l_do_reclaim(log); } }

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shaohua lishaohua li121100.00%3100.00%
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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; }

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shaohua lishaohua li71100.00%3100.00%
Total71100.00%3100.00%

struct r5l_recovery_ctx { struct page *meta_page; /* current meta */ sector_t meta_total_blocks; /* total size of current meta and data */ sector_t pos; /* recovery position */ u64 seq; /* recovery position seq */ };
static int r5l_read_meta_block(struct r5l_log *log, struct r5l_recovery_ctx *ctx) { struct page *page = ctx->meta_page; struct r5l_meta_block *mb; u32 crc, stored_crc; if (!sync_page_io(log->rdev, ctx->pos, PAGE_SIZE, page, READ, false)) return -EIO; mb = page_address(page); stored_crc = le32_to_cpu(mb->checksum); mb->checksum = 0; if (le32_to_cpu(mb->magic) != R5LOG_MAGIC || le64_to_cpu(mb->seq) != ctx->seq || mb->version != R5LOG_VERSION || le64_to_cpu(mb->position) != ctx->pos) return -EINVAL; crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE); if (stored_crc != crc) return -EINVAL; if (le32_to_cpu(mb->meta_size) > PAGE_SIZE) return -EINVAL; ctx->meta_total_blocks = BLOCK_SECTORS; return 0; }

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shaohua lishaohua li173100.00%2100.00%
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static int r5l_recovery_flush_one_stripe(struct r5l_log *log, struct r5l_recovery_ctx *ctx, sector_t stripe_sect, int *offset, sector_t *log_offset) { struct r5conf *conf = log->rdev->mddev->private; struct stripe_head *sh; struct r5l_payload_data_parity *payload; int disk_index; sh = raid5_get_active_stripe(conf, stripe_sect, 0, 0, 0); while (1) { payload = page_address(ctx->meta_page) + *offset; if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) { raid5_compute_sector(conf, le64_to_cpu(payload->location), 0, &disk_index, sh); sync_page_io(log->rdev, *log_offset, PAGE_SIZE, sh->dev[disk_index].page, READ, false); sh->dev[disk_index].log_checksum = le32_to_cpu(payload->checksum[0]); set_bit(R5_Wantwrite, &sh->dev[disk_index].flags); ctx->meta_total_blocks += BLOCK_SECTORS; } else { disk_index = sh->pd_idx; sync_page_io(log->rdev, *log_offset, PAGE_SIZE, sh->dev[disk_index].page, READ, false); sh->dev[disk_index].log_checksum = le32_to_cpu(payload->checksum[0]); set_bit(R5_Wantwrite, &sh->dev[disk_index].flags); if (sh->qd_idx >= 0) { disk_index = sh->qd_idx; sync_page_io(log->rdev, r5l_ring_add(log, *log_offset, BLOCK_SECTORS), PAGE_SIZE, sh->dev[disk_index].page, READ, false); sh->dev[disk_index].log_checksum = le32_to_cpu(payload->checksum[1]); set_bit(R5_Wantwrite, &sh->dev[disk_index].flags); } ctx->meta_total_blocks += BLOCK_SECTORS * conf->max_degraded; } *log_offset = r5l_ring_add(log, *log_offset, le32_to_cpu(payload->size)); *offset += sizeof(struct r5l_payload_data_parity) + sizeof(__le32) * (le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9)); if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_PARITY) break; } for (disk_index = 0; disk_index < sh->disks; disk_index++) { void *addr; u32 checksum; if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags)) continue; addr = kmap_atomic(sh->dev[disk_index].page); checksum = crc32c_le(log->uuid_checksum, addr, PAGE_SIZE); kunmap_atomic(addr); if (checksum != sh->dev[disk_index].log_checksum) goto error; } for (disk_index = 0; disk_index < sh->disks; disk_index++) { struct md_rdev *rdev, *rrdev; if (!test_and_clear_bit(R5_Wantwrite, &sh->dev[disk_index].flags)) continue; /* in case device is broken */ rdev = rcu_dereference(conf->disks[disk_index].rdev); if (rdev) sync_page_io(rdev, stripe_sect, PAGE_SIZE, sh->dev[disk_index].page, WRITE, false); rrdev = rcu_dereference(conf->disks[disk_index].replacement); if (rrdev) sync_page_io(rrdev, stripe_sect, PAGE_SIZE, sh->dev[disk_index].page, WRITE, false); } raid5_release_stripe(sh); return 0; error: for (disk_index = 0; disk_index < sh->disks; disk_index++) sh->dev[disk_index].flags = 0; raid5_release_stripe(sh); return -EINVAL; }

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shaohua lishaohua li667100.00%2100.00%
Total667100.00%2100.00%


static int r5l_recovery_flush_one_meta(struct r5l_log *log, struct r5l_recovery_ctx *ctx) { struct r5conf *conf = log->rdev->mddev->private; struct r5l_payload_data_parity *payload; struct r5l_meta_block *mb; int offset; sector_t log_offset; sector_t stripe_sector; mb = page_address(ctx->meta_page); offset = sizeof(struct r5l_meta_block); log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS); while (offset < le32_to_cpu(mb->meta_size)) { int dd; payload = (void *)mb + offset; stripe_sector = raid5_compute_sector(conf, le64_to_cpu(payload->location), 0, &dd, NULL); if (r5l_recovery_flush_one_stripe(log, ctx, stripe_sector, &offset, &log_offset)) return -EINVAL; } return 0; }

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shaohua lishaohua li149100.00%1100.00%
Total149100.00%1100.00%

/* copy data/parity from log to raid disks */
static void r5l_recovery_flush_log(struct r5l_log *log, struct r5l_recovery_ctx *ctx) { while (1) { if (r5l_read_meta_block(log, ctx)) return; if (r5l_recovery_flush_one_meta(log, ctx)) return; ctx->seq++; ctx->pos = r5l_ring_add(log, ctx->pos, ctx->meta_total_blocks); } }

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shaohua lishaohua li64100.00%1100.00%
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static int r5l_log_write_empty_meta_block(struct r5l_log *log, sector_t pos, u64 seq) { struct page *page; struct r5l_meta_block *mb; u32 crc; page = alloc_page(GFP_KERNEL | __GFP_ZERO); if (!page) return -ENOMEM; mb = page_address(page); mb->magic = cpu_to_le32(R5LOG_MAGIC); mb->version = R5LOG_VERSION; mb->meta_size = cpu_to_le32(sizeof(struct r5l_meta_block)); mb->seq = cpu_to_le64(seq); mb->position = cpu_to_le64(pos); crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE); mb->checksum = cpu_to_le32(crc); if (!sync_page_io(log->rdev, pos, PAGE_SIZE, page, WRITE_FUA, false)) { __free_page(page); return -EIO; } __free_page(page); return 0; }

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shaohua lishaohua li162100.00%2100.00%
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static int r5l_recovery_log(struct r5l_log *log) { struct r5l_recovery_ctx ctx; ctx.pos = log->last_checkpoint; ctx.seq = log->last_cp_seq; ctx.meta_page = alloc_page(GFP_KERNEL); if (!ctx.meta_page) return -ENOMEM; r5l_recovery_flush_log(log, &ctx); __free_page(ctx.meta_page); /* * we did a recovery. Now ctx.pos points to an invalid meta block. New * log will start here. but we can't let superblock point to last valid * meta block. The log might looks like: * | meta 1| meta 2| meta 3| * meta 1 is valid, meta 2 is invalid. meta 3 could be valid. If * superblock points to meta 1, we write a new valid meta 2n. if crash * happens again, new recovery will start from meta 1. Since meta 2n is * valid now, recovery will think meta 3 is valid, which is wrong. * The solution is we create a new meta in meta2 with its seq == meta * 1's seq + 10 and let superblock points to meta2. The same recovery will * not think meta 3 is a valid meta, because its seq doesn't match */ if (ctx.seq > log->last_cp_seq + 1) { int ret; ret = r5l_log_write_empty_meta_block(log, ctx.pos, ctx.seq + 10); if (ret) return ret; log->seq = ctx.seq + 11; log->log_start = r5l_ring_add(log, ctx.pos, BLOCK_SECTORS); r5l_write_super(log, ctx.pos); } else { log->log_start = ctx.pos; log->seq = ctx.seq; } return 0; }

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shaohua lishaohua li164100.00%3100.00%
Total164100.00%3100.00%


static void r5l_write_super(struct r5l_log *log, sector_t cp) { struct mddev *mddev = log->rdev->mddev; log->rdev->journal_tail = cp; set_bit(MD_CHANGE_DEVS, &mddev->flags); }

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shaohua lishaohua li43100.00%1100.00%
Total43100.00%1100.00%


static int r5l_load_log(struct r5l_log *log) { struct md_rdev *rdev = log->rdev; struct page *page; struct r5l_meta_block *mb; sector_t cp = log->rdev->journal_tail; u32 stored_crc, expected_crc; bool create_super = false; int ret; /* Make sure it's valid */ if (cp >= rdev->sectors || round_down(cp, BLOCK_SECTORS) != cp) cp = 0; page = alloc_page(GFP_KERNEL); if (!page) return -ENOMEM; if (!sync_page_io(rdev, cp, PAGE_SIZE, page, READ, false)) { ret = -EIO; goto ioerr; } mb = page_address(page); if (le32_to_cpu(mb->magic) != R5LOG_MAGIC || mb->version != R5LOG_VERSION) { create_super = true; goto create; } stored_crc = le32_to_cpu(mb->checksum); mb->checksum = 0; expected_crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE); if (stored_crc != expected_crc) { create_super = true; goto create; } if (le64_to_cpu(mb->position) != cp) { create_super = true; goto create; } create: if (create_super) { log->last_cp_seq = prandom_u32(); cp = 0; /* * Make sure super points to correct address. Log might have * data very soon. If super hasn't correct log tail address, * recovery can't find the log */ r5l_write_super(log, cp); } else log->last_cp_seq = le64_to_cpu(mb->seq); log->device_size = round_down(rdev->sectors, BLOCK_SECTORS); log->max_free_space = log->device_size >> RECLAIM_MAX_FREE_SPACE_SHIFT; if (log->max_free_space > RECLAIM_MAX_FREE_SPACE) log->max_free_space = RECLAIM_MAX_FREE_SPACE; log->last_checkpoint = cp; __free_page(page); return r5l_recovery_log(log); ioerr: __free_page(page); return ret; }

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shaohua lishaohua li317100.00%3100.00%
Total317100.00%3100.00%


int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) { struct request_queue *q = bdev_get_queue(rdev->bdev); struct r5l_log *log; if (PAGE_SIZE != 4096) return -EINVAL; log = kzalloc(sizeof(*log), GFP_KERNEL); if (!log) return -ENOMEM; log->rdev = rdev; log->need_cache_flush = 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); log->io_kc = KMEM_CACHE(r5l_io_unit, 0); if (!log->io_kc) goto io_kc; log->io_pool = mempool_create_slab_pool(R5L_POOL_SIZE, log->io_kc); if (!log->io_pool) goto io_pool; log->bs = bioset_create(R5L_POOL_SIZE, 0); if (!log->bs) goto io_bs; log->meta_pool = mempool_create_page_pool(R5L_POOL_SIZE, 0); if (!log->meta_pool) goto out_mempool; log->reclaim_thread = md_register_thread(r5l_reclaim_thread, log->rdev->mddev, "reclaim"); if (!log->reclaim_thread) goto reclaim_thread; init_waitqueue_head(&log->iounit_wait); INIT_LIST_HEAD(&log->no_mem_stripes); INIT_LIST_HEAD(&log->no_space_stripes); spin_lock_init(&log->no_space_stripes_lock); if (r5l_load_log(log)) goto error; rcu_assign_pointer(conf->log, log); set_bit(MD_HAS_JOURNAL, &conf->mddev->flags); return 0; error: md_unregister_thread(&log->reclaim_thread); reclaim_thread: mempool_destroy(log->meta_pool); out_mempool: bioset_free(log->bs); io_bs: mempool_destroy(log->io_pool); io_pool: kmem_cache_destroy(log->io_kc); io_kc: kfree(log); return -EINVAL; }

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shaohua lishaohua li27467.99%753.85%
christoph hellwigchristoph hellwig10927.05%538.46%
jens axboejens axboe204.96%17.69%
Total403100.00%13100.00%


void r5l_exit_log(struct r5l_log *log) { md_unregister_thread(&log->reclaim_thread); mempool_destroy(log->meta_pool); bioset_free(log->bs); mempool_destroy(log->io_pool); kmem_cache_destroy(log->io_kc); kfree(log); }

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shaohua lishaohua li3058.82%240.00%
christoph hellwigchristoph hellwig2141.18%360.00%
Total51100.00%5100.00%


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shaohua lishaohua li487780.80%1645.71%
christoph hellwigchristoph hellwig112918.70%1748.57%
jens axboejens axboe200.33%12.86%
guoqing jiangguoqing jiang100.17%12.86%
Total6036100.00%35100.00%
Directory: drivers/md
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