| /* |
| * Copyright (C) 2003 Sistina Software Limited. |
| * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved. |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include "dm-bio-record.h" |
| |
| #include <linux/init.h> |
| #include <linux/mempool.h> |
| #include <linux/module.h> |
| #include <linux/pagemap.h> |
| #include <linux/slab.h> |
| #include <linux/workqueue.h> |
| #include <linux/device-mapper.h> |
| #include <linux/dm-io.h> |
| #include <linux/dm-dirty-log.h> |
| #include <linux/dm-kcopyd.h> |
| #include <linux/dm-region-hash.h> |
| |
| #define DM_MSG_PREFIX "raid1" |
| |
| #define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */ |
| #define DM_KCOPYD_PAGES 64 |
| |
| #define DM_RAID1_HANDLE_ERRORS 0x01 |
| #define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS) |
| |
| static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped); |
| |
| /*----------------------------------------------------------------- |
| * Mirror set structures. |
| *---------------------------------------------------------------*/ |
| enum dm_raid1_error { |
| DM_RAID1_WRITE_ERROR, |
| DM_RAID1_FLUSH_ERROR, |
| DM_RAID1_SYNC_ERROR, |
| DM_RAID1_READ_ERROR |
| }; |
| |
| struct mirror { |
| struct mirror_set *ms; |
| atomic_t error_count; |
| unsigned long error_type; |
| struct dm_dev *dev; |
| sector_t offset; |
| }; |
| |
| struct mirror_set { |
| struct dm_target *ti; |
| struct list_head list; |
| |
| uint64_t features; |
| |
| spinlock_t lock; /* protects the lists */ |
| struct bio_list reads; |
| struct bio_list writes; |
| struct bio_list failures; |
| struct bio_list holds; /* bios are waiting until suspend */ |
| |
| struct dm_region_hash *rh; |
| struct dm_kcopyd_client *kcopyd_client; |
| struct dm_io_client *io_client; |
| mempool_t *read_record_pool; |
| |
| /* recovery */ |
| region_t nr_regions; |
| int in_sync; |
| int log_failure; |
| int leg_failure; |
| atomic_t suspend; |
| |
| atomic_t default_mirror; /* Default mirror */ |
| |
| struct workqueue_struct *kmirrord_wq; |
| struct work_struct kmirrord_work; |
| struct timer_list timer; |
| unsigned long timer_pending; |
| |
| struct work_struct trigger_event; |
| |
| unsigned nr_mirrors; |
| struct mirror mirror[0]; |
| }; |
| |
| static void wakeup_mirrord(void *context) |
| { |
| struct mirror_set *ms = context; |
| |
| queue_work(ms->kmirrord_wq, &ms->kmirrord_work); |
| } |
| |
| static void delayed_wake_fn(unsigned long data) |
| { |
| struct mirror_set *ms = (struct mirror_set *) data; |
| |
| clear_bit(0, &ms->timer_pending); |
| wakeup_mirrord(ms); |
| } |
| |
| static void delayed_wake(struct mirror_set *ms) |
| { |
| if (test_and_set_bit(0, &ms->timer_pending)) |
| return; |
| |
| ms->timer.expires = jiffies + HZ / 5; |
| ms->timer.data = (unsigned long) ms; |
| ms->timer.function = delayed_wake_fn; |
| add_timer(&ms->timer); |
| } |
| |
| static void wakeup_all_recovery_waiters(void *context) |
| { |
| wake_up_all(&_kmirrord_recovery_stopped); |
| } |
| |
| static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw) |
| { |
| unsigned long flags; |
| int should_wake = 0; |
| struct bio_list *bl; |
| |
| bl = (rw == WRITE) ? &ms->writes : &ms->reads; |
| spin_lock_irqsave(&ms->lock, flags); |
| should_wake = !(bl->head); |
| bio_list_add(bl, bio); |
| spin_unlock_irqrestore(&ms->lock, flags); |
| |
| if (should_wake) |
| wakeup_mirrord(ms); |
| } |
| |
| static void dispatch_bios(void *context, struct bio_list *bio_list) |
| { |
| struct mirror_set *ms = context; |
| struct bio *bio; |
| |
| while ((bio = bio_list_pop(bio_list))) |
| queue_bio(ms, bio, WRITE); |
| } |
| |
| #define MIN_READ_RECORDS 20 |
| struct dm_raid1_read_record { |
| struct mirror *m; |
| struct dm_bio_details details; |
| }; |
| |
| static struct kmem_cache *_dm_raid1_read_record_cache; |
| |
| /* |
| * Every mirror should look like this one. |
| */ |
| #define DEFAULT_MIRROR 0 |
| |
| /* |
| * This is yucky. We squirrel the mirror struct away inside |
| * bi_next for read/write buffers. This is safe since the bh |
| * doesn't get submitted to the lower levels of block layer. |
| */ |
| static struct mirror *bio_get_m(struct bio *bio) |
| { |
| return (struct mirror *) bio->bi_next; |
| } |
| |
| static void bio_set_m(struct bio *bio, struct mirror *m) |
| { |
| bio->bi_next = (struct bio *) m; |
| } |
| |
| static struct mirror *get_default_mirror(struct mirror_set *ms) |
| { |
| return &ms->mirror[atomic_read(&ms->default_mirror)]; |
| } |
| |
| static void set_default_mirror(struct mirror *m) |
| { |
| struct mirror_set *ms = m->ms; |
| struct mirror *m0 = &(ms->mirror[0]); |
| |
| atomic_set(&ms->default_mirror, m - m0); |
| } |
| |
| static struct mirror *get_valid_mirror(struct mirror_set *ms) |
| { |
| struct mirror *m; |
| |
| for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++) |
| if (!atomic_read(&m->error_count)) |
| return m; |
| |
| return NULL; |
| } |
| |
| /* fail_mirror |
| * @m: mirror device to fail |
| * @error_type: one of the enum's, DM_RAID1_*_ERROR |
| * |
| * If errors are being handled, record the type of |
| * error encountered for this device. If this type |
| * of error has already been recorded, we can return; |
| * otherwise, we must signal userspace by triggering |
| * an event. Additionally, if the device is the |
| * primary device, we must choose a new primary, but |
| * only if the mirror is in-sync. |
| * |
| * This function must not block. |
| */ |
| static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type) |
| { |
| struct mirror_set *ms = m->ms; |
| struct mirror *new; |
| |
| ms->leg_failure = 1; |
| |
| /* |
| * error_count is used for nothing more than a |
| * simple way to tell if a device has encountered |
| * errors. |
| */ |
| atomic_inc(&m->error_count); |
| |
| if (test_and_set_bit(error_type, &m->error_type)) |
| return; |
| |
| if (!errors_handled(ms)) |
| return; |
| |
| if (m != get_default_mirror(ms)) |
| goto out; |
| |
| if (!ms->in_sync) { |
| /* |
| * Better to issue requests to same failing device |
| * than to risk returning corrupt data. |
| */ |
| DMERR("Primary mirror (%s) failed while out-of-sync: " |
| "Reads may fail.", m->dev->name); |
| goto out; |
| } |
| |
| new = get_valid_mirror(ms); |
| if (new) |
| set_default_mirror(new); |
| else |
| DMWARN("All sides of mirror have failed."); |
| |
| out: |
| schedule_work(&ms->trigger_event); |
| } |
| |
| static int mirror_flush(struct dm_target *ti) |
| { |
| struct mirror_set *ms = ti->private; |
| unsigned long error_bits; |
| |
| unsigned int i; |
| struct dm_io_region io[ms->nr_mirrors]; |
| struct mirror *m; |
| struct dm_io_request io_req = { |
| .bi_rw = WRITE_FLUSH, |
| .mem.type = DM_IO_KMEM, |
| .mem.ptr.addr = NULL, |
| .client = ms->io_client, |
| }; |
| |
| for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) { |
| io[i].bdev = m->dev->bdev; |
| io[i].sector = 0; |
| io[i].count = 0; |
| } |
| |
| error_bits = -1; |
| dm_io(&io_req, ms->nr_mirrors, io, &error_bits); |
| if (unlikely(error_bits != 0)) { |
| for (i = 0; i < ms->nr_mirrors; i++) |
| if (test_bit(i, &error_bits)) |
| fail_mirror(ms->mirror + i, |
| DM_RAID1_FLUSH_ERROR); |
| return -EIO; |
| } |
| |
| return 0; |
| } |
| |
| /*----------------------------------------------------------------- |
| * Recovery. |
| * |
| * When a mirror is first activated we may find that some regions |
| * are in the no-sync state. We have to recover these by |
| * recopying from the default mirror to all the others. |
| *---------------------------------------------------------------*/ |
| static void recovery_complete(int read_err, unsigned long write_err, |
| void *context) |
| { |
| struct dm_region *reg = context; |
| struct mirror_set *ms = dm_rh_region_context(reg); |
| int m, bit = 0; |
| |
| if (read_err) { |
| /* Read error means the failure of default mirror. */ |
| DMERR_LIMIT("Unable to read primary mirror during recovery"); |
| fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR); |
| } |
| |
| if (write_err) { |
| DMERR_LIMIT("Write error during recovery (error = 0x%lx)", |
| write_err); |
| /* |
| * Bits correspond to devices (excluding default mirror). |
| * The default mirror cannot change during recovery. |
| */ |
| for (m = 0; m < ms->nr_mirrors; m++) { |
| if (&ms->mirror[m] == get_default_mirror(ms)) |
| continue; |
| if (test_bit(bit, &write_err)) |
| fail_mirror(ms->mirror + m, |
| DM_RAID1_SYNC_ERROR); |
| bit++; |
| } |
| } |
| |
| dm_rh_recovery_end(reg, !(read_err || write_err)); |
| } |
| |
| static int recover(struct mirror_set *ms, struct dm_region *reg) |
| { |
| int r; |
| unsigned i; |
| struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest; |
| struct mirror *m; |
| unsigned long flags = 0; |
| region_t key = dm_rh_get_region_key(reg); |
| sector_t region_size = dm_rh_get_region_size(ms->rh); |
| |
| /* fill in the source */ |
| m = get_default_mirror(ms); |
| from.bdev = m->dev->bdev; |
| from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key); |
| if (key == (ms->nr_regions - 1)) { |
| /* |
| * The final region may be smaller than |
| * region_size. |
| */ |
| from.count = ms->ti->len & (region_size - 1); |
| if (!from.count) |
| from.count = region_size; |
| } else |
| from.count = region_size; |
| |
| /* fill in the destinations */ |
| for (i = 0, dest = to; i < ms->nr_mirrors; i++) { |
| if (&ms->mirror[i] == get_default_mirror(ms)) |
| continue; |
| |
| m = ms->mirror + i; |
| dest->bdev = m->dev->bdev; |
| dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key); |
| dest->count = from.count; |
| dest++; |
| } |
| |
| /* hand to kcopyd */ |
| if (!errors_handled(ms)) |
| set_bit(DM_KCOPYD_IGNORE_ERROR, &flags); |
| |
| r = dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to, |
| flags, recovery_complete, reg); |
| |
| return r; |
| } |
| |
| static void do_recovery(struct mirror_set *ms) |
| { |
| struct dm_region *reg; |
| struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); |
| int r; |
| |
| /* |
| * Start quiescing some regions. |
| */ |
| dm_rh_recovery_prepare(ms->rh); |
| |
| /* |
| * Copy any already quiesced regions. |
| */ |
| while ((reg = dm_rh_recovery_start(ms->rh))) { |
| r = recover(ms, reg); |
| if (r) |
| dm_rh_recovery_end(reg, 0); |
| } |
| |
| /* |
| * Update the in sync flag. |
| */ |
| if (!ms->in_sync && |
| (log->type->get_sync_count(log) == ms->nr_regions)) { |
| /* the sync is complete */ |
| dm_table_event(ms->ti->table); |
| ms->in_sync = 1; |
| } |
| } |
| |
| /*----------------------------------------------------------------- |
| * Reads |
| *---------------------------------------------------------------*/ |
| static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector) |
| { |
| struct mirror *m = get_default_mirror(ms); |
| |
| do { |
| if (likely(!atomic_read(&m->error_count))) |
| return m; |
| |
| if (m-- == ms->mirror) |
| m += ms->nr_mirrors; |
| } while (m != get_default_mirror(ms)); |
| |
| return NULL; |
| } |
| |
| static int default_ok(struct mirror *m) |
| { |
| struct mirror *default_mirror = get_default_mirror(m->ms); |
| |
| return !atomic_read(&default_mirror->error_count); |
| } |
| |
| static int mirror_available(struct mirror_set *ms, struct bio *bio) |
| { |
| struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); |
| region_t region = dm_rh_bio_to_region(ms->rh, bio); |
| |
| if (log->type->in_sync(log, region, 0)) |
| return choose_mirror(ms, bio->bi_sector) ? 1 : 0; |
| |
| return 0; |
| } |
| |
| /* |
| * remap a buffer to a particular mirror. |
| */ |
| static sector_t map_sector(struct mirror *m, struct bio *bio) |
| { |
| if (unlikely(!bio->bi_size)) |
| return 0; |
| return m->offset + dm_target_offset(m->ms->ti, bio->bi_sector); |
| } |
| |
| static void map_bio(struct mirror *m, struct bio *bio) |
| { |
| bio->bi_bdev = m->dev->bdev; |
| bio->bi_sector = map_sector(m, bio); |
| } |
| |
| static void map_region(struct dm_io_region *io, struct mirror *m, |
| struct bio *bio) |
| { |
| io->bdev = m->dev->bdev; |
| io->sector = map_sector(m, bio); |
| io->count = bio->bi_size >> 9; |
| } |
| |
| static void hold_bio(struct mirror_set *ms, struct bio *bio) |
| { |
| /* |
| * Lock is required to avoid race condition during suspend |
| * process. |
| */ |
| spin_lock_irq(&ms->lock); |
| |
| if (atomic_read(&ms->suspend)) { |
| spin_unlock_irq(&ms->lock); |
| |
| /* |
| * If device is suspended, complete the bio. |
| */ |
| if (dm_noflush_suspending(ms->ti)) |
| bio_endio(bio, DM_ENDIO_REQUEUE); |
| else |
| bio_endio(bio, -EIO); |
| return; |
| } |
| |
| /* |
| * Hold bio until the suspend is complete. |
| */ |
| bio_list_add(&ms->holds, bio); |
| spin_unlock_irq(&ms->lock); |
| } |
| |
| /*----------------------------------------------------------------- |
| * Reads |
| *---------------------------------------------------------------*/ |
| static void read_callback(unsigned long error, void *context) |
| { |
| struct bio *bio = context; |
| struct mirror *m; |
| |
| m = bio_get_m(bio); |
| bio_set_m(bio, NULL); |
| |
| if (likely(!error)) { |
| bio_endio(bio, 0); |
| return; |
| } |
| |
| fail_mirror(m, DM_RAID1_READ_ERROR); |
| |
| if (likely(default_ok(m)) || mirror_available(m->ms, bio)) { |
| DMWARN_LIMIT("Read failure on mirror device %s. " |
| "Trying alternative device.", |
| m->dev->name); |
| queue_bio(m->ms, bio, bio_rw(bio)); |
| return; |
| } |
| |
| DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.", |
| m->dev->name); |
| bio_endio(bio, -EIO); |
| } |
| |
| /* Asynchronous read. */ |
| static void read_async_bio(struct mirror *m, struct bio *bio) |
| { |
| struct dm_io_region io; |
| struct dm_io_request io_req = { |
| .bi_rw = READ, |
| .mem.type = DM_IO_BVEC, |
| .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx, |
| .notify.fn = read_callback, |
| .notify.context = bio, |
| .client = m->ms->io_client, |
| }; |
| |
| map_region(&io, m, bio); |
| bio_set_m(bio, m); |
| BUG_ON(dm_io(&io_req, 1, &io, NULL)); |
| } |
| |
| static inline int region_in_sync(struct mirror_set *ms, region_t region, |
| int may_block) |
| { |
| int state = dm_rh_get_state(ms->rh, region, may_block); |
| return state == DM_RH_CLEAN || state == DM_RH_DIRTY; |
| } |
| |
| static void do_reads(struct mirror_set *ms, struct bio_list *reads) |
| { |
| region_t region; |
| struct bio *bio; |
| struct mirror *m; |
| |
| while ((bio = bio_list_pop(reads))) { |
| region = dm_rh_bio_to_region(ms->rh, bio); |
| m = get_default_mirror(ms); |
| |
| /* |
| * We can only read balance if the region is in sync. |
| */ |
| if (likely(region_in_sync(ms, region, 1))) |
| m = choose_mirror(ms, bio->bi_sector); |
| else if (m && atomic_read(&m->error_count)) |
| m = NULL; |
| |
| if (likely(m)) |
| read_async_bio(m, bio); |
| else |
| bio_endio(bio, -EIO); |
| } |
| } |
| |
| /*----------------------------------------------------------------- |
| * Writes. |
| * |
| * We do different things with the write io depending on the |
| * state of the region that it's in: |
| * |
| * SYNC: increment pending, use kcopyd to write to *all* mirrors |
| * RECOVERING: delay the io until recovery completes |
| * NOSYNC: increment pending, just write to the default mirror |
| *---------------------------------------------------------------*/ |
| |
| |
| static void write_callback(unsigned long error, void *context) |
| { |
| unsigned i, ret = 0; |
| struct bio *bio = (struct bio *) context; |
| struct mirror_set *ms; |
| int should_wake = 0; |
| unsigned long flags; |
| |
| ms = bio_get_m(bio)->ms; |
| bio_set_m(bio, NULL); |
| |
| /* |
| * NOTE: We don't decrement the pending count here, |
| * instead it is done by the targets endio function. |
| * This way we handle both writes to SYNC and NOSYNC |
| * regions with the same code. |
| */ |
| if (likely(!error)) { |
| bio_endio(bio, ret); |
| return; |
| } |
| |
| for (i = 0; i < ms->nr_mirrors; i++) |
| if (test_bit(i, &error)) |
| fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR); |
| |
| /* |
| * Need to raise event. Since raising |
| * events can block, we need to do it in |
| * the main thread. |
| */ |
| spin_lock_irqsave(&ms->lock, flags); |
| if (!ms->failures.head) |
| should_wake = 1; |
| bio_list_add(&ms->failures, bio); |
| spin_unlock_irqrestore(&ms->lock, flags); |
| if (should_wake) |
| wakeup_mirrord(ms); |
| } |
| |
| static void do_write(struct mirror_set *ms, struct bio *bio) |
| { |
| unsigned int i; |
| struct dm_io_region io[ms->nr_mirrors], *dest = io; |
| struct mirror *m; |
| struct dm_io_request io_req = { |
| .bi_rw = WRITE | (bio->bi_rw & WRITE_FLUSH_FUA), |
| .mem.type = DM_IO_BVEC, |
| .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx, |
| .notify.fn = write_callback, |
| .notify.context = bio, |
| .client = ms->io_client, |
| }; |
| |
| if (bio->bi_rw & REQ_DISCARD) { |
| io_req.bi_rw |= REQ_DISCARD; |
| io_req.mem.type = DM_IO_KMEM; |
| io_req.mem.ptr.addr = NULL; |
| } |
| |
| for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) |
| map_region(dest++, m, bio); |
| |
| /* |
| * Use default mirror because we only need it to retrieve the reference |
| * to the mirror set in write_callback(). |
| */ |
| bio_set_m(bio, get_default_mirror(ms)); |
| |
| BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL)); |
| } |
| |
| static void do_writes(struct mirror_set *ms, struct bio_list *writes) |
| { |
| int state; |
| struct bio *bio; |
| struct bio_list sync, nosync, recover, *this_list = NULL; |
| struct bio_list requeue; |
| struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); |
| region_t region; |
| |
| if (!writes->head) |
| return; |
| |
| /* |
| * Classify each write. |
| */ |
| bio_list_init(&sync); |
| bio_list_init(&nosync); |
| bio_list_init(&recover); |
| bio_list_init(&requeue); |
| |
| while ((bio = bio_list_pop(writes))) { |
| if ((bio->bi_rw & REQ_FLUSH) || |
| (bio->bi_rw & REQ_DISCARD)) { |
| bio_list_add(&sync, bio); |
| continue; |
| } |
| |
| region = dm_rh_bio_to_region(ms->rh, bio); |
| |
| if (log->type->is_remote_recovering && |
| log->type->is_remote_recovering(log, region)) { |
| bio_list_add(&requeue, bio); |
| continue; |
| } |
| |
| state = dm_rh_get_state(ms->rh, region, 1); |
| switch (state) { |
| case DM_RH_CLEAN: |
| case DM_RH_DIRTY: |
| this_list = &sync; |
| break; |
| |
| case DM_RH_NOSYNC: |
| this_list = &nosync; |
| break; |
| |
| case DM_RH_RECOVERING: |
| this_list = &recover; |
| break; |
| } |
| |
| bio_list_add(this_list, bio); |
| } |
| |
| /* |
| * Add bios that are delayed due to remote recovery |
| * back on to the write queue |
| */ |
| if (unlikely(requeue.head)) { |
| spin_lock_irq(&ms->lock); |
| bio_list_merge(&ms->writes, &requeue); |
| spin_unlock_irq(&ms->lock); |
| delayed_wake(ms); |
| } |
| |
| /* |
| * Increment the pending counts for any regions that will |
| * be written to (writes to recover regions are going to |
| * be delayed). |
| */ |
| dm_rh_inc_pending(ms->rh, &sync); |
| dm_rh_inc_pending(ms->rh, &nosync); |
| |
| /* |
| * If the flush fails on a previous call and succeeds here, |
| * we must not reset the log_failure variable. We need |
| * userspace interaction to do that. |
| */ |
| ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure; |
| |
| /* |
| * Dispatch io. |
| */ |
| if (unlikely(ms->log_failure) && errors_handled(ms)) { |
| spin_lock_irq(&ms->lock); |
| bio_list_merge(&ms->failures, &sync); |
| spin_unlock_irq(&ms->lock); |
| wakeup_mirrord(ms); |
| } else |
| while ((bio = bio_list_pop(&sync))) |
| do_write(ms, bio); |
| |
| while ((bio = bio_list_pop(&recover))) |
| dm_rh_delay(ms->rh, bio); |
| |
| while ((bio = bio_list_pop(&nosync))) { |
| if (unlikely(ms->leg_failure) && errors_handled(ms)) { |
| spin_lock_irq(&ms->lock); |
| bio_list_add(&ms->failures, bio); |
| spin_unlock_irq(&ms->lock); |
| wakeup_mirrord(ms); |
| } else { |
| map_bio(get_default_mirror(ms), bio); |
| generic_make_request(bio); |
| } |
| } |
| } |
| |
| static void do_failures(struct mirror_set *ms, struct bio_list *failures) |
| { |
| struct bio *bio; |
| |
| if (likely(!failures->head)) |
| return; |
| |
| /* |
| * If the log has failed, unattempted writes are being |
| * put on the holds list. We can't issue those writes |
| * until a log has been marked, so we must store them. |
| * |
| * If a 'noflush' suspend is in progress, we can requeue |
| * the I/O's to the core. This give userspace a chance |
| * to reconfigure the mirror, at which point the core |
| * will reissue the writes. If the 'noflush' flag is |
| * not set, we have no choice but to return errors. |
| * |
| * Some writes on the failures list may have been |
| * submitted before the log failure and represent a |
| * failure to write to one of the devices. It is ok |
| * for us to treat them the same and requeue them |
| * as well. |
| */ |
| while ((bio = bio_list_pop(failures))) { |
| if (!ms->log_failure) { |
| ms->in_sync = 0; |
| dm_rh_mark_nosync(ms->rh, bio); |
| } |
| |
| /* |
| * If all the legs are dead, fail the I/O. |
| * If we have been told to handle errors, hold the bio |
| * and wait for userspace to deal with the problem. |
| * Otherwise pretend that the I/O succeeded. (This would |
| * be wrong if the failed leg returned after reboot and |
| * got replicated back to the good legs.) |
| */ |
| if (!get_valid_mirror(ms)) |
| bio_endio(bio, -EIO); |
| else if (errors_handled(ms)) |
| hold_bio(ms, bio); |
| else |
| bio_endio(bio, 0); |
| } |
| } |
| |
| static void trigger_event(struct work_struct *work) |
| { |
| struct mirror_set *ms = |
| container_of(work, struct mirror_set, trigger_event); |
| |
| dm_table_event(ms->ti->table); |
| } |
| |
| /*----------------------------------------------------------------- |
| * kmirrord |
| *---------------------------------------------------------------*/ |
| static void do_mirror(struct work_struct *work) |
| { |
| struct mirror_set *ms = container_of(work, struct mirror_set, |
| kmirrord_work); |
| struct bio_list reads, writes, failures; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ms->lock, flags); |
| reads = ms->reads; |
| writes = ms->writes; |
| failures = ms->failures; |
| bio_list_init(&ms->reads); |
| bio_list_init(&ms->writes); |
| bio_list_init(&ms->failures); |
| spin_unlock_irqrestore(&ms->lock, flags); |
| |
| dm_rh_update_states(ms->rh, errors_handled(ms)); |
| do_recovery(ms); |
| do_reads(ms, &reads); |
| do_writes(ms, &writes); |
| do_failures(ms, &failures); |
| } |
| |
| /*----------------------------------------------------------------- |
| * Target functions |
| *---------------------------------------------------------------*/ |
| static struct mirror_set *alloc_context(unsigned int nr_mirrors, |
| uint32_t region_size, |
| struct dm_target *ti, |
| struct dm_dirty_log *dl) |
| { |
| size_t len; |
| struct mirror_set *ms = NULL; |
| |
| len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors); |
| |
| ms = kzalloc(len, GFP_KERNEL); |
| if (!ms) { |
| ti->error = "Cannot allocate mirror context"; |
| return NULL; |
| } |
| |
| spin_lock_init(&ms->lock); |
| bio_list_init(&ms->reads); |
| bio_list_init(&ms->writes); |
| bio_list_init(&ms->failures); |
| bio_list_init(&ms->holds); |
| |
| ms->ti = ti; |
| ms->nr_mirrors = nr_mirrors; |
| ms->nr_regions = dm_sector_div_up(ti->len, region_size); |
| ms->in_sync = 0; |
| ms->log_failure = 0; |
| ms->leg_failure = 0; |
| atomic_set(&ms->suspend, 0); |
| atomic_set(&ms->default_mirror, DEFAULT_MIRROR); |
| |
| ms->read_record_pool = mempool_create_slab_pool(MIN_READ_RECORDS, |
| _dm_raid1_read_record_cache); |
| |
| if (!ms->read_record_pool) { |
| ti->error = "Error creating mirror read_record_pool"; |
| kfree(ms); |
| return NULL; |
| } |
| |
| ms->io_client = dm_io_client_create(); |
| if (IS_ERR(ms->io_client)) { |
| ti->error = "Error creating dm_io client"; |
| mempool_destroy(ms->read_record_pool); |
| kfree(ms); |
| return NULL; |
| } |
| |
| ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord, |
| wakeup_all_recovery_waiters, |
| ms->ti->begin, MAX_RECOVERY, |
| dl, region_size, ms->nr_regions); |
| if (IS_ERR(ms->rh)) { |
| ti->error = "Error creating dirty region hash"; |
| dm_io_client_destroy(ms->io_client); |
| mempool_destroy(ms->read_record_pool); |
| kfree(ms); |
| return NULL; |
| } |
| |
| return ms; |
| } |
| |
| static void free_context(struct mirror_set *ms, struct dm_target *ti, |
| unsigned int m) |
| { |
| while (m--) |
| dm_put_device(ti, ms->mirror[m].dev); |
| |
| dm_io_client_destroy(ms->io_client); |
| dm_region_hash_destroy(ms->rh); |
| mempool_destroy(ms->read_record_pool); |
| kfree(ms); |
| } |
| |
| static int get_mirror(struct mirror_set *ms, struct dm_target *ti, |
| unsigned int mirror, char **argv) |
| { |
| unsigned long long offset; |
| |
| if (sscanf(argv[1], "%llu", &offset) != 1) { |
| ti->error = "Invalid offset"; |
| return -EINVAL; |
| } |
| |
| if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), |
| &ms->mirror[mirror].dev)) { |
| ti->error = "Device lookup failure"; |
| return -ENXIO; |
| } |
| |
| ms->mirror[mirror].ms = ms; |
| atomic_set(&(ms->mirror[mirror].error_count), 0); |
| ms->mirror[mirror].error_type = 0; |
| ms->mirror[mirror].offset = offset; |
| |
| return 0; |
| } |
| |
| /* |
| * Create dirty log: log_type #log_params <log_params> |
| */ |
| static struct dm_dirty_log *create_dirty_log(struct dm_target *ti, |
| unsigned argc, char **argv, |
| unsigned *args_used) |
| { |
| unsigned param_count; |
| struct dm_dirty_log *dl; |
| |
| if (argc < 2) { |
| ti->error = "Insufficient mirror log arguments"; |
| return NULL; |
| } |
| |
| if (sscanf(argv[1], "%u", ¶m_count) != 1) { |
| ti->error = "Invalid mirror log argument count"; |
| return NULL; |
| } |
| |
| *args_used = 2 + param_count; |
| |
| if (argc < *args_used) { |
| ti->error = "Insufficient mirror log arguments"; |
| return NULL; |
| } |
| |
| dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count, |
| argv + 2); |
| if (!dl) { |
| ti->error = "Error creating mirror dirty log"; |
| return NULL; |
| } |
| |
| return dl; |
| } |
| |
| static int parse_features(struct mirror_set *ms, unsigned argc, char **argv, |
| unsigned *args_used) |
| { |
| unsigned num_features; |
| struct dm_target *ti = ms->ti; |
| |
| *args_used = 0; |
| |
| if (!argc) |
| return 0; |
| |
| if (sscanf(argv[0], "%u", &num_features) != 1) { |
| ti->error = "Invalid number of features"; |
| return -EINVAL; |
| } |
| |
| argc--; |
| argv++; |
| (*args_used)++; |
| |
| if (num_features > argc) { |
| ti->error = "Not enough arguments to support feature count"; |
| return -EINVAL; |
| } |
| |
| if (!strcmp("handle_errors", argv[0])) |
| ms->features |= DM_RAID1_HANDLE_ERRORS; |
| else { |
| ti->error = "Unrecognised feature requested"; |
| return -EINVAL; |
| } |
| |
| (*args_used)++; |
| |
| return 0; |
| } |
| |
| /* |
| * Construct a mirror mapping: |
| * |
| * log_type #log_params <log_params> |
| * #mirrors [mirror_path offset]{2,} |
| * [#features <features>] |
| * |
| * log_type is "core" or "disk" |
| * #log_params is between 1 and 3 |
| * |
| * If present, features must be "handle_errors". |
| */ |
| static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) |
| { |
| int r; |
| unsigned int nr_mirrors, m, args_used; |
| struct mirror_set *ms; |
| struct dm_dirty_log *dl; |
| |
| dl = create_dirty_log(ti, argc, argv, &args_used); |
| if (!dl) |
| return -EINVAL; |
| |
| argv += args_used; |
| argc -= args_used; |
| |
| if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 || |
| nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) { |
| ti->error = "Invalid number of mirrors"; |
| dm_dirty_log_destroy(dl); |
| return -EINVAL; |
| } |
| |
| argv++, argc--; |
| |
| if (argc < nr_mirrors * 2) { |
| ti->error = "Too few mirror arguments"; |
| dm_dirty_log_destroy(dl); |
| return -EINVAL; |
| } |
| |
| ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl); |
| if (!ms) { |
| dm_dirty_log_destroy(dl); |
| return -ENOMEM; |
| } |
| |
| /* Get the mirror parameter sets */ |
| for (m = 0; m < nr_mirrors; m++) { |
| r = get_mirror(ms, ti, m, argv); |
| if (r) { |
| free_context(ms, ti, m); |
| return r; |
| } |
| argv += 2; |
| argc -= 2; |
| } |
| |
| ti->private = ms; |
| ti->split_io = dm_rh_get_region_size(ms->rh); |
| ti->num_flush_requests = 1; |
| ti->num_discard_requests = 1; |
| |
| ms->kmirrord_wq = alloc_workqueue("kmirrord", |
| WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0); |
| if (!ms->kmirrord_wq) { |
| DMERR("couldn't start kmirrord"); |
| r = -ENOMEM; |
| goto err_free_context; |
| } |
| INIT_WORK(&ms->kmirrord_work, do_mirror); |
| init_timer(&ms->timer); |
| ms->timer_pending = 0; |
| INIT_WORK(&ms->trigger_event, trigger_event); |
| |
| r = parse_features(ms, argc, argv, &args_used); |
| if (r) |
| goto err_destroy_wq; |
| |
| argv += args_used; |
| argc -= args_used; |
| |
| /* |
| * Any read-balancing addition depends on the |
| * DM_RAID1_HANDLE_ERRORS flag being present. |
| * This is because the decision to balance depends |
| * on the sync state of a region. If the above |
| * flag is not present, we ignore errors; and |
| * the sync state may be inaccurate. |
| */ |
| |
| if (argc) { |
| ti->error = "Too many mirror arguments"; |
| r = -EINVAL; |
| goto err_destroy_wq; |
| } |
| |
| r = dm_kcopyd_client_create(DM_KCOPYD_PAGES, &ms->kcopyd_client); |
| if (r) |
| goto err_destroy_wq; |
| |
| wakeup_mirrord(ms); |
| return 0; |
| |
| err_destroy_wq: |
| destroy_workqueue(ms->kmirrord_wq); |
| err_free_context: |
| free_context(ms, ti, ms->nr_mirrors); |
| return r; |
| } |
| |
| static void mirror_dtr(struct dm_target *ti) |
| { |
| struct mirror_set *ms = (struct mirror_set *) ti->private; |
| |
| del_timer_sync(&ms->timer); |
| flush_workqueue(ms->kmirrord_wq); |
| flush_work_sync(&ms->trigger_event); |
| dm_kcopyd_client_destroy(ms->kcopyd_client); |
| destroy_workqueue(ms->kmirrord_wq); |
| free_context(ms, ti, ms->nr_mirrors); |
| } |
| |
| /* |
| * Mirror mapping function |
| */ |
| static int mirror_map(struct dm_target *ti, struct bio *bio, |
| union map_info *map_context) |
| { |
| int r, rw = bio_rw(bio); |
| struct mirror *m; |
| struct mirror_set *ms = ti->private; |
| struct dm_raid1_read_record *read_record = NULL; |
| struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); |
| |
| if (rw == WRITE) { |
| /* Save region for mirror_end_io() handler */ |
| map_context->ll = dm_rh_bio_to_region(ms->rh, bio); |
| queue_bio(ms, bio, rw); |
| return DM_MAPIO_SUBMITTED; |
| } |
| |
| r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0); |
| if (r < 0 && r != -EWOULDBLOCK) |
| return r; |
| |
| /* |
| * If region is not in-sync queue the bio. |
| */ |
| if (!r || (r == -EWOULDBLOCK)) { |
| if (rw == READA) |
| return -EWOULDBLOCK; |
| |
| queue_bio(ms, bio, rw); |
| return DM_MAPIO_SUBMITTED; |
| } |
| |
| /* |
| * The region is in-sync and we can perform reads directly. |
| * Store enough information so we can retry if it fails. |
| */ |
| m = choose_mirror(ms, bio->bi_sector); |
| if (unlikely(!m)) |
| return -EIO; |
| |
| read_record = mempool_alloc(ms->read_record_pool, GFP_NOIO); |
| if (likely(read_record)) { |
| dm_bio_record(&read_record->details, bio); |
| map_context->ptr = read_record; |
| read_record->m = m; |
| } |
| |
| map_bio(m, bio); |
| |
| return DM_MAPIO_REMAPPED; |
| } |
| |
| static int mirror_end_io(struct dm_target *ti, struct bio *bio, |
| int error, union map_info *map_context) |
| { |
| int rw = bio_rw(bio); |
| struct mirror_set *ms = (struct mirror_set *) ti->private; |
| struct mirror *m = NULL; |
| struct dm_bio_details *bd = NULL; |
| struct dm_raid1_read_record *read_record = map_context->ptr; |
| |
| /* |
| * We need to dec pending if this was a write. |
| */ |
| if (rw == WRITE) { |
| if (!(bio->bi_rw & REQ_FLUSH)) |
| dm_rh_dec(ms->rh, map_context->ll); |
| return error; |
| } |
| |
| if (error == -EOPNOTSUPP) |
| goto out; |
| |
| if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD)) |
| goto out; |
| |
| if (unlikely(error)) { |
| if (!read_record) { |
| /* |
| * There wasn't enough memory to record necessary |
| * information for a retry or there was no other |
| * mirror in-sync. |
| */ |
| DMERR_LIMIT("Mirror read failed."); |
| return -EIO; |
| } |
| |
| m = read_record->m; |
| |
| DMERR("Mirror read failed from %s. Trying alternative device.", |
| m->dev->name); |
| |
| fail_mirror(m, DM_RAID1_READ_ERROR); |
| |
| /* |
| * A failed read is requeued for another attempt using an intact |
| * mirror. |
| */ |
| if (default_ok(m) || mirror_available(ms, bio)) { |
| bd = &read_record->details; |
| |
| dm_bio_restore(bd, bio); |
| mempool_free(read_record, ms->read_record_pool); |
| map_context->ptr = NULL; |
| queue_bio(ms, bio, rw); |
| return 1; |
| } |
| DMERR("All replicated volumes dead, failing I/O"); |
| } |
| |
| out: |
| if (read_record) { |
| mempool_free(read_record, ms->read_record_pool); |
| map_context->ptr = NULL; |
| } |
| |
| return error; |
| } |
| |
| static void mirror_presuspend(struct dm_target *ti) |
| { |
| struct mirror_set *ms = (struct mirror_set *) ti->private; |
| struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); |
| |
| struct bio_list holds; |
| struct bio *bio; |
| |
| atomic_set(&ms->suspend, 1); |
| |
| /* |
| * Process bios in the hold list to start recovery waiting |
| * for bios in the hold list. After the process, no bio has |
| * a chance to be added in the hold list because ms->suspend |
| * is set. |
| */ |
| spin_lock_irq(&ms->lock); |
| holds = ms->holds; |
| bio_list_init(&ms->holds); |
| spin_unlock_irq(&ms->lock); |
| |
| while ((bio = bio_list_pop(&holds))) |
| hold_bio(ms, bio); |
| |
| /* |
| * We must finish up all the work that we've |
| * generated (i.e. recovery work). |
| */ |
| dm_rh_stop_recovery(ms->rh); |
| |
| wait_event(_kmirrord_recovery_stopped, |
| !dm_rh_recovery_in_flight(ms->rh)); |
| |
| if (log->type->presuspend && log->type->presuspend(log)) |
| /* FIXME: need better error handling */ |
| DMWARN("log presuspend failed"); |
| |
| /* |
| * Now that recovery is complete/stopped and the |
| * delayed bios are queued, we need to wait for |
| * the worker thread to complete. This way, |
| * we know that all of our I/O has been pushed. |
| */ |
| flush_workqueue(ms->kmirrord_wq); |
| } |
| |
| static void mirror_postsuspend(struct dm_target *ti) |
| { |
| struct mirror_set *ms = ti->private; |
| struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); |
| |
| if (log->type->postsuspend && log->type->postsuspend(log)) |
| /* FIXME: need better error handling */ |
| DMWARN("log postsuspend failed"); |
| } |
| |
| static void mirror_resume(struct dm_target *ti) |
| { |
| struct mirror_set *ms = ti->private; |
| struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); |
| |
| atomic_set(&ms->suspend, 0); |
| if (log->type->resume && log->type->resume(log)) |
| /* FIXME: need better error handling */ |
| DMWARN("log resume failed"); |
| dm_rh_start_recovery(ms->rh); |
| } |
| |
| /* |
| * device_status_char |
| * @m: mirror device/leg we want the status of |
| * |
| * We return one character representing the most severe error |
| * we have encountered. |
| * A => Alive - No failures |
| * D => Dead - A write failure occurred leaving mirror out-of-sync |
| * S => Sync - A sychronization failure occurred, mirror out-of-sync |
| * R => Read - A read failure occurred, mirror data unaffected |
| * |
| * Returns: <char> |
| */ |
| static char device_status_char(struct mirror *m) |
| { |
| if (!atomic_read(&(m->error_count))) |
| return 'A'; |
| |
| return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' : |
| (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' : |
| (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' : |
| (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U'; |
| } |
| |
| |
| static int mirror_status(struct dm_target *ti, status_type_t type, |
| char *result, unsigned int maxlen) |
| { |
| unsigned int m, sz = 0; |
| struct mirror_set *ms = (struct mirror_set *) ti->private; |
| struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); |
| char buffer[ms->nr_mirrors + 1]; |
| |
| switch (type) { |
| case STATUSTYPE_INFO: |
| DMEMIT("%d ", ms->nr_mirrors); |
| for (m = 0; m < ms->nr_mirrors; m++) { |
| DMEMIT("%s ", ms->mirror[m].dev->name); |
| buffer[m] = device_status_char(&(ms->mirror[m])); |
| } |
| buffer[m] = '\0'; |
| |
| DMEMIT("%llu/%llu 1 %s ", |
| (unsigned long long)log->type->get_sync_count(log), |
| (unsigned long long)ms->nr_regions, buffer); |
| |
| sz += log->type->status(log, type, result+sz, maxlen-sz); |
| |
| break; |
| |
| case STATUSTYPE_TABLE: |
| sz = log->type->status(log, type, result, maxlen); |
| |
| DMEMIT("%d", ms->nr_mirrors); |
| for (m = 0; m < ms->nr_mirrors; m++) |
| DMEMIT(" %s %llu", ms->mirror[m].dev->name, |
| (unsigned long long)ms->mirror[m].offset); |
| |
| if (ms->features & DM_RAID1_HANDLE_ERRORS) |
| DMEMIT(" 1 handle_errors"); |
| } |
| |
| return 0; |
| } |
| |
| static int mirror_iterate_devices(struct dm_target *ti, |
| iterate_devices_callout_fn fn, void *data) |
| { |
| struct mirror_set *ms = ti->private; |
| int ret = 0; |
| unsigned i; |
| |
| for (i = 0; !ret && i < ms->nr_mirrors; i++) |
| ret = fn(ti, ms->mirror[i].dev, |
| ms->mirror[i].offset, ti->len, data); |
| |
| return ret; |
| } |
| |
| static struct target_type mirror_target = { |
| .name = "mirror", |
| .version = {1, 12, 1}, |
| .module = THIS_MODULE, |
| .ctr = mirror_ctr, |
| .dtr = mirror_dtr, |
| .map = mirror_map, |
| .end_io = mirror_end_io, |
| .presuspend = mirror_presuspend, |
| .postsuspend = mirror_postsuspend, |
| .resume = mirror_resume, |
| .status = mirror_status, |
| .iterate_devices = mirror_iterate_devices, |
| }; |
| |
| static int __init dm_mirror_init(void) |
| { |
| int r; |
| |
| _dm_raid1_read_record_cache = KMEM_CACHE(dm_raid1_read_record, 0); |
| if (!_dm_raid1_read_record_cache) { |
| DMERR("Can't allocate dm_raid1_read_record cache"); |
| r = -ENOMEM; |
| goto bad_cache; |
| } |
| |
| r = dm_register_target(&mirror_target); |
| if (r < 0) { |
| DMERR("Failed to register mirror target"); |
| goto bad_target; |
| } |
| |
| return 0; |
| |
| bad_target: |
| kmem_cache_destroy(_dm_raid1_read_record_cache); |
| bad_cache: |
| return r; |
| } |
| |
| static void __exit dm_mirror_exit(void) |
| { |
| dm_unregister_target(&mirror_target); |
| kmem_cache_destroy(_dm_raid1_read_record_cache); |
| } |
| |
| /* Module hooks */ |
| module_init(dm_mirror_init); |
| module_exit(dm_mirror_exit); |
| |
| MODULE_DESCRIPTION(DM_NAME " mirror target"); |
| MODULE_AUTHOR("Joe Thornber"); |
| MODULE_LICENSE("GPL"); |