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-rw-r--r--drivers/md/raid5-cache.c1191
1 files changed, 1191 insertions, 0 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
new file mode 100644
index 000000000..b887e04d7
--- /dev/null
+++ b/drivers/md/raid5-cache.c
@@ -0,0 +1,1191 @@
+/*
+ * Copyright (C) 2015 Shaohua Li <shli@fb.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/wait.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/raid/md_p.h>
+#include <linux/crc32c.h>
+#include <linux/random.h>
+#include "md.h"
+#include "raid5.h"
+
+/*
+ * metadata/data stored in disk with 4k size unit (a block) regardless
+ * underneath hardware sector size. only works with PAGE_SIZE == 4096
+ */
+#define BLOCK_SECTORS (8)
+
+/*
+ * reclaim runs every 1/4 disk size or 10G reclaimable space. This can prevent
+ * recovery scans a very long log
+ */
+#define RECLAIM_MAX_FREE_SPACE (10 * 1024 * 1024 * 2) /* sector */
+#define RECLAIM_MAX_FREE_SPACE_SHIFT (2)
+
+struct r5l_log {
+ struct md_rdev *rdev;
+
+ u32 uuid_checksum;
+
+ sector_t device_size; /* log device size, round to
+ * BLOCK_SECTORS */
+ sector_t max_free_space; /* reclaim run if free space is at
+ * this size */
+
+ sector_t last_checkpoint; /* log tail. where recovery scan
+ * starts from */
+ u64 last_cp_seq; /* log tail sequence */
+
+ sector_t log_start; /* log head. where new data appends */
+ u64 seq; /* log head sequence */
+
+ sector_t next_checkpoint;
+ u64 next_cp_seq;
+
+ struct mutex io_mutex;
+ struct r5l_io_unit *current_io; /* current io_unit accepting new data */
+
+ spinlock_t io_list_lock;
+ struct list_head running_ios; /* io_units which are still running,
+ * and have not yet been completely
+ * written to the log */
+ struct list_head io_end_ios; /* io_units which have been completely
+ * written to the log but not yet written
+ * to the RAID */
+ struct list_head flushing_ios; /* io_units which are waiting for log
+ * cache flush */
+ struct list_head finished_ios; /* io_units which settle down in log disk */
+ struct bio flush_bio;
+
+ struct kmem_cache *io_kc;
+
+ struct md_thread *reclaim_thread;
+ unsigned long reclaim_target; /* number of space that need to be
+ * reclaimed. if it's 0, reclaim spaces
+ * used by io_units which are in
+ * IO_UNIT_STRIPE_END state (eg, reclaim
+ * dones't wait for specific io_unit
+ * switching to IO_UNIT_STRIPE_END
+ * state) */
+ wait_queue_head_t iounit_wait;
+
+ struct list_head no_space_stripes; /* pending stripes, log has no space */
+ spinlock_t no_space_stripes_lock;
+
+ bool need_cache_flush;
+ bool in_teardown;
+};
+
+/*
+ * an IO range starts from a meta data block and end at the next meta data
+ * block. The io unit's the meta data block tracks data/parity followed it. io
+ * unit is written to log disk with normal write, as we always flush log disk
+ * first and then start move data to raid disks, there is no requirement to
+ * write io unit with FLUSH/FUA
+ */
+struct r5l_io_unit {
+ struct r5l_log *log;
+
+ struct page *meta_page; /* store meta block */
+ int meta_offset; /* current offset in meta_page */
+
+ struct bio *current_bio;/* current_bio accepting new data */
+
+ atomic_t pending_stripe;/* how many stripes not flushed to raid */
+ u64 seq; /* seq number of the metablock */
+ sector_t log_start; /* where the io_unit starts */
+ sector_t log_end; /* where the io_unit ends */
+ struct list_head log_sibling; /* log->running_ios */
+ struct list_head stripe_list; /* stripes added to the io_unit */
+
+ int state;
+ bool need_split_bio;
+};
+
+/* r5l_io_unit state */
+enum r5l_io_unit_state {
+ IO_UNIT_RUNNING = 0, /* accepting new IO */
+ IO_UNIT_IO_START = 1, /* io_unit bio start writing to log,
+ * don't accepting new bio */
+ IO_UNIT_IO_END = 2, /* io_unit bio finish writing to log */
+ IO_UNIT_STRIPE_END = 3, /* stripes data finished writing to raid */
+};
+
+static sector_t r5l_ring_add(struct r5l_log *log, sector_t start, sector_t inc)
+{
+ start += inc;
+ if (start >= log->device_size)
+ start = start - log->device_size;
+ return start;
+}
+
+static sector_t r5l_ring_distance(struct r5l_log *log, sector_t start,
+ sector_t end)
+{
+ if (end >= start)
+ return end - start;
+ else
+ return end + log->device_size - start;
+}
+
+static bool r5l_has_free_space(struct r5l_log *log, sector_t size)
+{
+ sector_t used_size;
+
+ used_size = r5l_ring_distance(log, log->last_checkpoint,
+ log->log_start);
+
+ return log->device_size > used_size + size;
+}
+
+static void r5l_free_io_unit(struct r5l_log *log, struct r5l_io_unit *io)
+{
+ __free_page(io->meta_page);
+ kmem_cache_free(log->io_kc, io);
+}
+
+static void r5l_move_io_unit_list(struct list_head *from, struct list_head *to,
+ enum r5l_io_unit_state state)
+{
+ struct r5l_io_unit *io;
+
+ while (!list_empty(from)) {
+ io = list_first_entry(from, struct r5l_io_unit, log_sibling);
+ /* don't change list order */
+ if (io->state >= state)
+ list_move_tail(&io->log_sibling, to);
+ else
+ break;
+ }
+}
+
+static void __r5l_set_io_unit_state(struct r5l_io_unit *io,
+ enum r5l_io_unit_state state)
+{
+ if (WARN_ON(io->state >= state))
+ return;
+ io->state = state;
+}
+
+static void r5l_io_run_stripes(struct r5l_io_unit *io)
+{
+ struct stripe_head *sh, *next;
+
+ list_for_each_entry_safe(sh, next, &io->stripe_list, log_list) {
+ list_del_init(&sh->log_list);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ raid5_release_stripe(sh);
+ }
+}
+
+static void r5l_log_run_stripes(struct r5l_log *log)
+{
+ struct r5l_io_unit *io, *next;
+
+ assert_spin_locked(&log->io_list_lock);
+
+ list_for_each_entry_safe(io, next, &log->running_ios, log_sibling) {
+ /* don't change list order */
+ if (io->state < IO_UNIT_IO_END)
+ break;
+
+ list_move_tail(&io->log_sibling, &log->finished_ios);
+ r5l_io_run_stripes(io);
+ }
+}
+
+static void r5l_log_endio(struct bio *bio)
+{
+ struct r5l_io_unit *io = bio->bi_private;
+ struct r5l_log *log = io->log;
+ unsigned long flags;
+
+ if (bio->bi_error)
+ md_error(log->rdev->mddev, log->rdev);
+
+ bio_put(bio);
+
+ spin_lock_irqsave(&log->io_list_lock, flags);
+ __r5l_set_io_unit_state(io, IO_UNIT_IO_END);
+ if (log->need_cache_flush)
+ r5l_move_io_unit_list(&log->running_ios, &log->io_end_ios,
+ IO_UNIT_IO_END);
+ else
+ r5l_log_run_stripes(log);
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+
+ if (log->need_cache_flush)
+ md_wakeup_thread(log->rdev->mddev->thread);
+}
+
+static void r5l_submit_current_io(struct r5l_log *log)
+{
+ struct r5l_io_unit *io = log->current_io;
+ struct r5l_meta_block *block;
+ unsigned long flags;
+ u32 crc;
+
+ if (!io)
+ return;
+
+ block = page_address(io->meta_page);
+ block->meta_size = cpu_to_le32(io->meta_offset);
+ crc = crc32c_le(log->uuid_checksum, block, PAGE_SIZE);
+ block->checksum = cpu_to_le32(crc);
+
+ log->current_io = NULL;
+ spin_lock_irqsave(&log->io_list_lock, flags);
+ __r5l_set_io_unit_state(io, IO_UNIT_IO_START);
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+
+ submit_bio(WRITE, io->current_bio);
+}
+
+static struct bio *r5l_bio_alloc(struct r5l_log *log)
+{
+ struct bio *bio = bio_kmalloc(GFP_NOIO | __GFP_NOFAIL, BIO_MAX_PAGES);
+
+ bio->bi_rw = WRITE;
+ bio->bi_bdev = log->rdev->bdev;
+ bio->bi_iter.bi_sector = log->rdev->data_offset + log->log_start;
+
+ return bio;
+}
+
+static void r5_reserve_log_entry(struct r5l_log *log, struct r5l_io_unit *io)
+{
+ log->log_start = r5l_ring_add(log, log->log_start, BLOCK_SECTORS);
+
+ /*
+ * If we filled up the log device start from the beginning again,
+ * which will require a new bio.
+ *
+ * Note: for this to work properly the log size needs to me a multiple
+ * of BLOCK_SECTORS.
+ */
+ if (log->log_start == 0)
+ io->need_split_bio = true;
+
+ io->log_end = log->log_start;
+}
+
+static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log)
+{
+ struct r5l_io_unit *io;
+ struct r5l_meta_block *block;
+
+ /* We can't handle memory allocate failure so far */
+ io = kmem_cache_zalloc(log->io_kc, GFP_NOIO | __GFP_NOFAIL);
+ io->log = log;
+ INIT_LIST_HEAD(&io->log_sibling);
+ INIT_LIST_HEAD(&io->stripe_list);
+ io->state = IO_UNIT_RUNNING;
+
+ io->meta_page = alloc_page(GFP_NOIO | __GFP_NOFAIL | __GFP_ZERO);
+ block = page_address(io->meta_page);
+ block->magic = cpu_to_le32(R5LOG_MAGIC);
+ block->version = R5LOG_VERSION;
+ block->seq = cpu_to_le64(log->seq);
+ block->position = cpu_to_le64(log->log_start);
+
+ io->log_start = log->log_start;
+ io->meta_offset = sizeof(struct r5l_meta_block);
+ io->seq = log->seq++;
+
+ io->current_bio = r5l_bio_alloc(log);
+ io->current_bio->bi_end_io = r5l_log_endio;
+ io->current_bio->bi_private = io;
+ bio_add_page(io->current_bio, io->meta_page, PAGE_SIZE, 0);
+
+ r5_reserve_log_entry(log, io);
+
+ spin_lock_irq(&log->io_list_lock);
+ list_add_tail(&io->log_sibling, &log->running_ios);
+ spin_unlock_irq(&log->io_list_lock);
+
+ return io;
+}
+
+static int r5l_get_meta(struct r5l_log *log, unsigned int payload_size)
+{
+ if (log->current_io &&
+ log->current_io->meta_offset + payload_size > PAGE_SIZE)
+ r5l_submit_current_io(log);
+
+ if (!log->current_io)
+ log->current_io = r5l_new_meta(log);
+ return 0;
+}
+
+static void r5l_append_payload_meta(struct r5l_log *log, u16 type,
+ sector_t location,
+ u32 checksum1, u32 checksum2,
+ bool checksum2_valid)
+{
+ struct r5l_io_unit *io = log->current_io;
+ struct r5l_payload_data_parity *payload;
+
+ payload = page_address(io->meta_page) + io->meta_offset;
+ payload->header.type = cpu_to_le16(type);
+ payload->header.flags = cpu_to_le16(0);
+ payload->size = cpu_to_le32((1 + !!checksum2_valid) <<
+ (PAGE_SHIFT - 9));
+ payload->location = cpu_to_le64(location);
+ payload->checksum[0] = cpu_to_le32(checksum1);
+ if (checksum2_valid)
+ payload->checksum[1] = cpu_to_le32(checksum2);
+
+ io->meta_offset += sizeof(struct r5l_payload_data_parity) +
+ sizeof(__le32) * (1 + !!checksum2_valid);
+}
+
+static void r5l_append_payload_page(struct r5l_log *log, struct page *page)
+{
+ struct r5l_io_unit *io = log->current_io;
+
+ if (io->need_split_bio) {
+ struct bio *prev = io->current_bio;
+
+ io->current_bio = r5l_bio_alloc(log);
+ bio_chain(io->current_bio, prev);
+
+ submit_bio(WRITE, prev);
+ }
+
+ if (!bio_add_page(io->current_bio, page, PAGE_SIZE, 0))
+ BUG();
+
+ r5_reserve_log_entry(log, io);
+}
+
+static void r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh,
+ int data_pages, int parity_pages)
+{
+ int i;
+ int meta_size;
+ struct r5l_io_unit *io;
+
+ meta_size =
+ ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32))
+ * data_pages) +
+ sizeof(struct r5l_payload_data_parity) +
+ sizeof(__le32) * parity_pages;
+
+ r5l_get_meta(log, meta_size);
+ io = log->current_io;
+
+ for (i = 0; i < sh->disks; i++) {
+ if (!test_bit(R5_Wantwrite, &sh->dev[i].flags))
+ continue;
+ if (i == sh->pd_idx || i == sh->qd_idx)
+ continue;
+ r5l_append_payload_meta(log, R5LOG_PAYLOAD_DATA,
+ raid5_compute_blocknr(sh, i, 0),
+ sh->dev[i].log_checksum, 0, false);
+ r5l_append_payload_page(log, sh->dev[i].page);
+ }
+
+ if (sh->qd_idx >= 0) {
+ r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
+ sh->sector, sh->dev[sh->pd_idx].log_checksum,
+ sh->dev[sh->qd_idx].log_checksum, true);
+ r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
+ r5l_append_payload_page(log, sh->dev[sh->qd_idx].page);
+ } else {
+ r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
+ sh->sector, sh->dev[sh->pd_idx].log_checksum,
+ 0, false);
+ r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
+ }
+
+ list_add_tail(&sh->log_list, &io->stripe_list);
+ atomic_inc(&io->pending_stripe);
+ sh->log_io = io;
+}
+
+static void r5l_wake_reclaim(struct r5l_log *log, sector_t space);
+/*
+ * running in raid5d, where reclaim could wait for raid5d too (when it flushes
+ * data from log to raid disks), so we shouldn't wait for reclaim here
+ */
+int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh)
+{
+ int write_disks = 0;
+ int data_pages, parity_pages;
+ int meta_size;
+ int reserve;
+ int i;
+
+ if (!log)
+ return -EAGAIN;
+ /* Don't support stripe batch */
+ if (sh->log_io || !test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags) ||
+ test_bit(STRIPE_SYNCING, &sh->state)) {
+ /* the stripe is written to log, we start writing it to raid */
+ clear_bit(STRIPE_LOG_TRAPPED, &sh->state);
+ return -EAGAIN;
+ }
+
+ for (i = 0; i < sh->disks; i++) {
+ void *addr;
+
+ if (!test_bit(R5_Wantwrite, &sh->dev[i].flags))
+ continue;
+ write_disks++;
+ /* checksum is already calculated in last run */
+ if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
+ continue;
+ addr = kmap_atomic(sh->dev[i].page);
+ sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum,
+ addr, PAGE_SIZE);
+ kunmap_atomic(addr);
+ }
+ parity_pages = 1 + !!(sh->qd_idx >= 0);
+ data_pages = write_disks - parity_pages;
+
+ meta_size =
+ ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32))
+ * data_pages) +
+ sizeof(struct r5l_payload_data_parity) +
+ sizeof(__le32) * parity_pages;
+ /* Doesn't work with very big raid array */
+ if (meta_size + sizeof(struct r5l_meta_block) > PAGE_SIZE)
+ return -EINVAL;
+
+ set_bit(STRIPE_LOG_TRAPPED, &sh->state);
+ /*
+ * The stripe must enter state machine again to finish the write, so
+ * don't delay.
+ */
+ clear_bit(STRIPE_DELAYED, &sh->state);
+ atomic_inc(&sh->count);
+
+ mutex_lock(&log->io_mutex);
+ /* meta + data */
+ reserve = (1 + write_disks) << (PAGE_SHIFT - 9);
+ if (r5l_has_free_space(log, reserve))
+ r5l_log_stripe(log, sh, data_pages, parity_pages);
+ else {
+ spin_lock(&log->no_space_stripes_lock);
+ list_add_tail(&sh->log_list, &log->no_space_stripes);
+ spin_unlock(&log->no_space_stripes_lock);
+
+ r5l_wake_reclaim(log, reserve);
+ }
+ mutex_unlock(&log->io_mutex);
+
+ return 0;
+}
+
+void r5l_write_stripe_run(struct r5l_log *log)
+{
+ if (!log)
+ return;
+ mutex_lock(&log->io_mutex);
+ r5l_submit_current_io(log);
+ mutex_unlock(&log->io_mutex);
+}
+
+int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio)
+{
+ if (!log)
+ return -ENODEV;
+ /*
+ * we flush log disk cache first, then write stripe data to raid disks.
+ * So if bio is finished, the log disk cache is flushed already. The
+ * recovery guarantees we can recovery the bio from log disk, so we
+ * don't need to flush again
+ */
+ if (bio->bi_iter.bi_size == 0) {
+ bio_endio(bio);
+ return 0;
+ }
+ bio->bi_rw &= ~REQ_FLUSH;
+ return -EAGAIN;
+}
+
+/* This will run after log space is reclaimed */
+static void r5l_run_no_space_stripes(struct r5l_log *log)
+{
+ struct stripe_head *sh;
+
+ spin_lock(&log->no_space_stripes_lock);
+ while (!list_empty(&log->no_space_stripes)) {
+ sh = list_first_entry(&log->no_space_stripes,
+ struct stripe_head, log_list);
+ list_del_init(&sh->log_list);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ raid5_release_stripe(sh);
+ }
+ spin_unlock(&log->no_space_stripes_lock);
+}
+
+static sector_t r5l_reclaimable_space(struct r5l_log *log)
+{
+ return r5l_ring_distance(log, log->last_checkpoint,
+ log->next_checkpoint);
+}
+
+static bool r5l_complete_finished_ios(struct r5l_log *log)
+{
+ struct r5l_io_unit *io, *next;
+ bool found = false;
+
+ assert_spin_locked(&log->io_list_lock);
+
+ list_for_each_entry_safe(io, next, &log->finished_ios, log_sibling) {
+ /* don't change list order */
+ if (io->state < IO_UNIT_STRIPE_END)
+ break;
+
+ log->next_checkpoint = io->log_start;
+ log->next_cp_seq = io->seq;
+
+ list_del(&io->log_sibling);
+ r5l_free_io_unit(log, io);
+
+ found = true;
+ }
+
+ return found;
+}
+
+static void __r5l_stripe_write_finished(struct r5l_io_unit *io)
+{
+ struct r5l_log *log = io->log;
+ unsigned long flags;
+
+ spin_lock_irqsave(&log->io_list_lock, flags);
+ __r5l_set_io_unit_state(io, IO_UNIT_STRIPE_END);
+
+ if (!r5l_complete_finished_ios(log)) {
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+ return;
+ }
+
+ if (r5l_reclaimable_space(log) > log->max_free_space)
+ r5l_wake_reclaim(log, 0);
+
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+ wake_up(&log->iounit_wait);
+}
+
+void r5l_stripe_write_finished(struct stripe_head *sh)
+{
+ struct r5l_io_unit *io;
+
+ io = sh->log_io;
+ sh->log_io = NULL;
+
+ if (io && atomic_dec_and_test(&io->pending_stripe))
+ __r5l_stripe_write_finished(io);
+}
+
+static void r5l_log_flush_endio(struct bio *bio)
+{
+ struct r5l_log *log = container_of(bio, struct r5l_log,
+ flush_bio);
+ unsigned long flags;
+ struct r5l_io_unit *io;
+
+ if (bio->bi_error)
+ md_error(log->rdev->mddev, log->rdev);
+
+ spin_lock_irqsave(&log->io_list_lock, flags);
+ list_for_each_entry(io, &log->flushing_ios, log_sibling)
+ r5l_io_run_stripes(io);
+ list_splice_tail_init(&log->flushing_ios, &log->finished_ios);
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+}
+
+/*
+ * Starting dispatch IO to raid.
+ * io_unit(meta) consists of a log. There is one situation we want to avoid. A
+ * broken meta in the middle of a log causes recovery can't find meta at the
+ * head of log. If operations require meta at the head persistent in log, we
+ * must make sure meta before it persistent in log too. A case is:
+ *
+ * stripe data/parity is in log, we start write stripe to raid disks. stripe
+ * data/parity must be persistent in log before we do the write to raid disks.
+ *
+ * The solution is we restrictly maintain io_unit list order. In this case, we
+ * only write stripes of an io_unit to raid disks till the io_unit is the first
+ * one whose data/parity is in log.
+ */
+void r5l_flush_stripe_to_raid(struct r5l_log *log)
+{
+ bool do_flush;
+
+ if (!log || !log->need_cache_flush)
+ return;
+
+ spin_lock_irq(&log->io_list_lock);
+ /* flush bio is running */
+ if (!list_empty(&log->flushing_ios)) {
+ spin_unlock_irq(&log->io_list_lock);
+ return;
+ }
+ list_splice_tail_init(&log->io_end_ios, &log->flushing_ios);
+ do_flush = !list_empty(&log->flushing_ios);
+ spin_unlock_irq(&log->io_list_lock);
+
+ if (!do_flush)
+ return;
+ bio_reset(&log->flush_bio);
+ log->flush_bio.bi_bdev = log->rdev->bdev;
+ log->flush_bio.bi_end_io = r5l_log_flush_endio;
+ submit_bio(WRITE_FLUSH, &log->flush_bio);
+}
+
+static void r5l_write_super(struct r5l_log *log, sector_t cp);
+static void r5l_write_super_and_discard_space(struct r5l_log *log,
+ sector_t end)
+{
+ struct block_device *bdev = log->rdev->bdev;
+ struct mddev *mddev;
+
+ r5l_write_super(log, end);
+
+ if (!blk_queue_discard(bdev_get_queue(bdev)))
+ return;
+
+ mddev = log->rdev->mddev;
+ /*
+ * This is to avoid a deadlock. r5l_quiesce holds reconfig_mutex and
+ * wait for this thread to finish. This thread waits for
+ * MD_CHANGE_PENDING clear, which is supposed to be done in
+ * md_check_recovery(). md_check_recovery() tries to get
+ * reconfig_mutex. Since r5l_quiesce already holds the mutex,
+ * md_check_recovery() fails, so the PENDING never get cleared. The
+ * in_teardown check workaround this issue.
+ */
+ if (!log->in_teardown) {
+ set_bit(MD_CHANGE_DEVS, &mddev->flags);
+ set_bit(MD_CHANGE_PENDING, &mddev->flags);
+ md_wakeup_thread(mddev->thread);
+ wait_event(mddev->sb_wait,
+ !test_bit(MD_CHANGE_PENDING, &mddev->flags) ||
+ log->in_teardown);
+ /*
+ * r5l_quiesce could run after in_teardown check and hold
+ * mutex first. Superblock might get updated twice.
+ */
+ if (log->in_teardown)
+ md_update_sb(mddev, 1);
+ } else {
+ WARN_ON(!mddev_is_locked(mddev));
+ md_update_sb(mddev, 1);
+ }
+
+ /* discard IO error really doesn't matter, ignore it */
+ if (log->last_checkpoint < end) {
+ blkdev_issue_discard(bdev,
+ log->last_checkpoint + log->rdev->data_offset,
+ end - log->last_checkpoint, GFP_NOIO, 0);
+ } else {
+ blkdev_issue_discard(bdev,
+ log->last_checkpoint + log->rdev->data_offset,
+ log->device_size - log->last_checkpoint,
+ GFP_NOIO, 0);
+ blkdev_issue_discard(bdev, log->rdev->data_offset, end,
+ GFP_NOIO, 0);
+ }
+}
+
+
+static void r5l_do_reclaim(struct r5l_log *log)
+{
+ sector_t reclaim_target = xchg(&log->reclaim_target, 0);
+ sector_t reclaimable;
+ sector_t next_checkpoint;
+ u64 next_cp_seq;
+
+ spin_lock_irq(&log->io_list_lock);
+ /*
+ * move proper io_unit to reclaim list. We should not change the order.
+ * reclaimable/unreclaimable io_unit can be mixed in the list, we
+ * shouldn't reuse space of an unreclaimable io_unit
+ */
+ while (1) {
+ reclaimable = r5l_reclaimable_space(log);
+ if (reclaimable >= reclaim_target ||
+ (list_empty(&log->running_ios) &&
+ list_empty(&log->io_end_ios) &&
+ list_empty(&log->flushing_ios) &&
+ list_empty(&log->finished_ios)))
+ break;
+
+ md_wakeup_thread(log->rdev->mddev->thread);
+ wait_event_lock_irq(log->iounit_wait,
+ r5l_reclaimable_space(log) > reclaimable,
+ log->io_list_lock);
+ }
+
+ next_checkpoint = log->next_checkpoint;
+ next_cp_seq = log->next_cp_seq;
+ spin_unlock_irq(&log->io_list_lock);
+
+ BUG_ON(reclaimable < 0);
+ if (reclaimable == 0)
+ return;
+
+ /*
+ * write_super will flush cache of each raid disk. We must write super
+ * here, because the log area might be reused soon and we don't want to
+ * confuse recovery
+ */
+ r5l_write_super_and_discard_space(log, next_checkpoint);
+
+ mutex_lock(&log->io_mutex);
+ log->last_checkpoint = next_checkpoint;
+ log->last_cp_seq = next_cp_seq;
+ mutex_unlock(&log->io_mutex);
+
+ r5l_run_no_space_stripes(log);
+}
+
+static void r5l_reclaim_thread(struct md_thread *thread)
+{
+ struct mddev *mddev = thread->mddev;
+ struct r5conf *conf = mddev->private;
+ struct r5l_log *log = conf->log;
+
+ if (!log)
+ return;
+ r5l_do_reclaim(log);
+}
+
+static void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
+{
+ unsigned long target;
+ unsigned long new = (unsigned long)space; /* overflow in theory */
+
+ do {
+ target = log->reclaim_target;
+ if (new < target)
+ return;
+ } while (cmpxchg(&log->reclaim_target, target, new) != target);
+ md_wakeup_thread(log->reclaim_thread);
+}
+
+void r5l_quiesce(struct r5l_log *log, int state)
+{
+ struct mddev *mddev;
+ if (!log || state == 2)
+ return;
+ if (state == 0) {
+ log->in_teardown = 0;
+ log->reclaim_thread = md_register_thread(r5l_reclaim_thread,
+ log->rdev->mddev, "reclaim");
+ } else if (state == 1) {
+ /*
+ * at this point all stripes are finished, so io_unit is at
+ * least in STRIPE_END state
+ */
+ log->in_teardown = 1;
+ /* make sure r5l_write_super_and_discard_space exits */
+ mddev = log->rdev->mddev;
+ wake_up(&mddev->sb_wait);
+ r5l_wake_reclaim(log, -1L);
+ md_unregister_thread(&log->reclaim_thread);
+ r5l_do_reclaim(log);
+ }
+}
+
+bool r5l_log_disk_error(struct r5conf *conf)
+{
+ /* don't allow write if journal disk is missing */
+ if (!conf->log)
+ return test_bit(MD_HAS_JOURNAL, &conf->mddev->flags);
+ return test_bit(Faulty, &conf->log->rdev->flags);
+}
+
+struct r5l_recovery_ctx {
+ struct page *meta_page; /* current meta */
+ sector_t meta_total_blocks; /* total size of current meta and data */
+ sector_t pos; /* recovery position */
+ u64 seq; /* recovery position seq */
+};
+
+static int r5l_read_meta_block(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx)
+{
+ struct page *page = ctx->meta_page;
+ struct r5l_meta_block *mb;
+ u32 crc, stored_crc;
+
+ if (!sync_page_io(log->rdev, ctx->pos, PAGE_SIZE, page, READ, false))
+ return -EIO;
+
+ mb = page_address(page);
+ stored_crc = le32_to_cpu(mb->checksum);
+ mb->checksum = 0;
+
+ if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
+ le64_to_cpu(mb->seq) != ctx->seq ||
+ mb->version != R5LOG_VERSION ||
+ le64_to_cpu(mb->position) != ctx->pos)
+ return -EINVAL;
+
+ crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
+ if (stored_crc != crc)
+ return -EINVAL;
+
+ if (le32_to_cpu(mb->meta_size) > PAGE_SIZE)
+ return -EINVAL;
+
+ ctx->meta_total_blocks = BLOCK_SECTORS;
+
+ return 0;
+}
+
+static int r5l_recovery_flush_one_stripe(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx,
+ sector_t stripe_sect,
+ int *offset, sector_t *log_offset)
+{
+ struct r5conf *conf = log->rdev->mddev->private;
+ struct stripe_head *sh;
+ struct r5l_payload_data_parity *payload;
+ int disk_index;
+
+ sh = raid5_get_active_stripe(conf, stripe_sect, 0, 0, 0);
+ while (1) {
+ payload = page_address(ctx->meta_page) + *offset;
+
+ if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) {
+ raid5_compute_sector(conf,
+ le64_to_cpu(payload->location), 0,
+ &disk_index, sh);
+
+ sync_page_io(log->rdev, *log_offset, PAGE_SIZE,
+ sh->dev[disk_index].page, READ, false);
+ sh->dev[disk_index].log_checksum =
+ le32_to_cpu(payload->checksum[0]);
+ set_bit(R5_Wantwrite, &sh->dev[disk_index].flags);
+ ctx->meta_total_blocks += BLOCK_SECTORS;
+ } else {
+ disk_index = sh->pd_idx;
+ sync_page_io(log->rdev, *log_offset, PAGE_SIZE,
+ sh->dev[disk_index].page, READ, false);
+ sh->dev[disk_index].log_checksum =
+ le32_to_cpu(payload->checksum[0]);
+ set_bit(R5_Wantwrite, &sh->dev[disk_index].flags);
+
+ if (sh->qd_idx >= 0) {
+ disk_index = sh->qd_idx;
+ sync_page_io(log->rdev,
+ r5l_ring_add(log, *log_offset, BLOCK_SECTORS),
+ PAGE_SIZE, sh->dev[disk_index].page,
+ READ, false);
+ sh->dev[disk_index].log_checksum =
+ le32_to_cpu(payload->checksum[1]);
+ set_bit(R5_Wantwrite,
+ &sh->dev[disk_index].flags);
+ }
+ ctx->meta_total_blocks += BLOCK_SECTORS * conf->max_degraded;
+ }
+
+ *log_offset = r5l_ring_add(log, *log_offset,
+ le32_to_cpu(payload->size));
+ *offset += sizeof(struct r5l_payload_data_parity) +
+ sizeof(__le32) *
+ (le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9));
+ if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_PARITY)
+ break;
+ }
+
+ for (disk_index = 0; disk_index < sh->disks; disk_index++) {
+ void *addr;
+ u32 checksum;
+
+ if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags))
+ continue;
+ addr = kmap_atomic(sh->dev[disk_index].page);
+ checksum = crc32c_le(log->uuid_checksum, addr, PAGE_SIZE);
+ kunmap_atomic(addr);
+ if (checksum != sh->dev[disk_index].log_checksum)
+ goto error;
+ }
+
+ for (disk_index = 0; disk_index < sh->disks; disk_index++) {
+ struct md_rdev *rdev, *rrdev;
+
+ if (!test_and_clear_bit(R5_Wantwrite,
+ &sh->dev[disk_index].flags))
+ continue;
+
+ /* in case device is broken */
+ rdev = rcu_dereference(conf->disks[disk_index].rdev);
+ if (rdev)
+ sync_page_io(rdev, stripe_sect, PAGE_SIZE,
+ sh->dev[disk_index].page, WRITE, false);
+ rrdev = rcu_dereference(conf->disks[disk_index].replacement);
+ if (rrdev)
+ sync_page_io(rrdev, stripe_sect, PAGE_SIZE,
+ sh->dev[disk_index].page, WRITE, false);
+ }
+ raid5_release_stripe(sh);
+ return 0;
+
+error:
+ for (disk_index = 0; disk_index < sh->disks; disk_index++)
+ sh->dev[disk_index].flags = 0;
+ raid5_release_stripe(sh);
+ return -EINVAL;
+}
+
+static int r5l_recovery_flush_one_meta(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx)
+{
+ struct r5conf *conf = log->rdev->mddev->private;
+ struct r5l_payload_data_parity *payload;
+ struct r5l_meta_block *mb;
+ int offset;
+ sector_t log_offset;
+ sector_t stripe_sector;
+
+ mb = page_address(ctx->meta_page);
+ offset = sizeof(struct r5l_meta_block);
+ log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
+
+ while (offset < le32_to_cpu(mb->meta_size)) {
+ int dd;
+
+ payload = (void *)mb + offset;
+ stripe_sector = raid5_compute_sector(conf,
+ le64_to_cpu(payload->location), 0, &dd, NULL);
+ if (r5l_recovery_flush_one_stripe(log, ctx, stripe_sector,
+ &offset, &log_offset))
+ return -EINVAL;
+ }
+ return 0;
+}
+
+/* copy data/parity from log to raid disks */
+static void r5l_recovery_flush_log(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx)
+{
+ while (1) {
+ if (r5l_read_meta_block(log, ctx))
+ return;
+ if (r5l_recovery_flush_one_meta(log, ctx))
+ return;
+ ctx->seq++;
+ ctx->pos = r5l_ring_add(log, ctx->pos, ctx->meta_total_blocks);
+ }
+}
+
+static int r5l_log_write_empty_meta_block(struct r5l_log *log, sector_t pos,
+ u64 seq)
+{
+ struct page *page;
+ struct r5l_meta_block *mb;
+ u32 crc;
+
+ page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ if (!page)
+ return -ENOMEM;
+ mb = page_address(page);
+ mb->magic = cpu_to_le32(R5LOG_MAGIC);
+ mb->version = R5LOG_VERSION;
+ mb->meta_size = cpu_to_le32(sizeof(struct r5l_meta_block));
+ mb->seq = cpu_to_le64(seq);
+ mb->position = cpu_to_le64(pos);
+ crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
+ mb->checksum = cpu_to_le32(crc);
+
+ if (!sync_page_io(log->rdev, pos, PAGE_SIZE, page, WRITE_FUA, false)) {
+ __free_page(page);
+ return -EIO;
+ }
+ __free_page(page);
+ return 0;
+}
+
+static int r5l_recovery_log(struct r5l_log *log)
+{
+ struct r5l_recovery_ctx ctx;
+
+ ctx.pos = log->last_checkpoint;
+ ctx.seq = log->last_cp_seq;
+ ctx.meta_page = alloc_page(GFP_KERNEL);
+ if (!ctx.meta_page)
+ return -ENOMEM;
+
+ r5l_recovery_flush_log(log, &ctx);
+ __free_page(ctx.meta_page);
+
+ /*
+ * we did a recovery. Now ctx.pos points to an invalid meta block. New
+ * log will start here. but we can't let superblock point to last valid
+ * meta block. The log might looks like:
+ * | meta 1| meta 2| meta 3|
+ * meta 1 is valid, meta 2 is invalid. meta 3 could be valid. If
+ * superblock points to meta 1, we write a new valid meta 2n. if crash
+ * happens again, new recovery will start from meta 1. Since meta 2n is
+ * valid now, recovery will think meta 3 is valid, which is wrong.
+ * The solution is we create a new meta in meta2 with its seq == meta
+ * 1's seq + 10 and let superblock points to meta2. The same recovery will
+ * not think meta 3 is a valid meta, because its seq doesn't match
+ */
+ if (ctx.seq > log->last_cp_seq + 1) {
+ int ret;
+
+ ret = r5l_log_write_empty_meta_block(log, ctx.pos, ctx.seq + 10);
+ if (ret)
+ return ret;
+ log->seq = ctx.seq + 11;
+ log->log_start = r5l_ring_add(log, ctx.pos, BLOCK_SECTORS);
+ r5l_write_super(log, ctx.pos);
+ } else {
+ log->log_start = ctx.pos;
+ log->seq = ctx.seq;
+ }
+ return 0;
+}
+
+static void r5l_write_super(struct r5l_log *log, sector_t cp)
+{
+ struct mddev *mddev = log->rdev->mddev;
+
+ log->rdev->journal_tail = cp;
+ set_bit(MD_CHANGE_DEVS, &mddev->flags);
+}
+
+static int r5l_load_log(struct r5l_log *log)
+{
+ struct md_rdev *rdev = log->rdev;
+ struct page *page;
+ struct r5l_meta_block *mb;
+ sector_t cp = log->rdev->journal_tail;
+ u32 stored_crc, expected_crc;
+ bool create_super = false;
+ int ret;
+
+ /* Make sure it's valid */
+ if (cp >= rdev->sectors || round_down(cp, BLOCK_SECTORS) != cp)
+ cp = 0;
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ return -ENOMEM;
+
+ if (!sync_page_io(rdev, cp, PAGE_SIZE, page, READ, false)) {
+ ret = -EIO;
+ goto ioerr;
+ }
+ mb = page_address(page);
+
+ if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
+ mb->version != R5LOG_VERSION) {
+ create_super = true;
+ goto create;
+ }
+ stored_crc = le32_to_cpu(mb->checksum);
+ mb->checksum = 0;
+ expected_crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
+ if (stored_crc != expected_crc) {
+ create_super = true;
+ goto create;
+ }
+ if (le64_to_cpu(mb->position) != cp) {
+ create_super = true;
+ goto create;
+ }
+create:
+ if (create_super) {
+ log->last_cp_seq = prandom_u32();
+ cp = 0;
+ /*
+ * Make sure super points to correct address. Log might have
+ * data very soon. If super hasn't correct log tail address,
+ * recovery can't find the log
+ */
+ r5l_write_super(log, cp);
+ } else
+ log->last_cp_seq = le64_to_cpu(mb->seq);
+
+ log->device_size = round_down(rdev->sectors, BLOCK_SECTORS);
+ log->max_free_space = log->device_size >> RECLAIM_MAX_FREE_SPACE_SHIFT;
+ if (log->max_free_space > RECLAIM_MAX_FREE_SPACE)
+ log->max_free_space = RECLAIM_MAX_FREE_SPACE;
+ log->last_checkpoint = cp;
+
+ __free_page(page);
+
+ return r5l_recovery_log(log);
+ioerr:
+ __free_page(page);
+ return ret;
+}
+
+int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
+{
+ struct r5l_log *log;
+
+ if (PAGE_SIZE != 4096)
+ return -EINVAL;
+ log = kzalloc(sizeof(*log), GFP_KERNEL);
+ if (!log)
+ return -ENOMEM;
+ log->rdev = rdev;
+
+ log->need_cache_flush = (rdev->bdev->bd_disk->queue->flush_flags != 0);
+
+ log->uuid_checksum = crc32c_le(~0, rdev->mddev->uuid,
+ sizeof(rdev->mddev->uuid));
+
+ mutex_init(&log->io_mutex);
+
+ spin_lock_init(&log->io_list_lock);
+ INIT_LIST_HEAD(&log->running_ios);
+ INIT_LIST_HEAD(&log->io_end_ios);
+ INIT_LIST_HEAD(&log->flushing_ios);
+ INIT_LIST_HEAD(&log->finished_ios);
+ bio_init(&log->flush_bio);
+
+ log->io_kc = KMEM_CACHE(r5l_io_unit, 0);
+ if (!log->io_kc)
+ goto io_kc;
+
+ log->reclaim_thread = md_register_thread(r5l_reclaim_thread,
+ log->rdev->mddev, "reclaim");
+ if (!log->reclaim_thread)
+ goto reclaim_thread;
+ init_waitqueue_head(&log->iounit_wait);
+
+ INIT_LIST_HEAD(&log->no_space_stripes);
+ spin_lock_init(&log->no_space_stripes_lock);
+
+ if (r5l_load_log(log))
+ goto error;
+
+ conf->log = log;
+ return 0;
+error:
+ md_unregister_thread(&log->reclaim_thread);
+reclaim_thread:
+ kmem_cache_destroy(log->io_kc);
+io_kc:
+ kfree(log);
+ return -EINVAL;
+}
+
+void r5l_exit_log(struct r5l_log *log)
+{
+ md_unregister_thread(&log->reclaim_thread);
+ kmem_cache_destroy(log->io_kc);
+ kfree(log);
+}