diff options
Diffstat (limited to 'drivers/block/drbd/drbd_actlog.c')
| -rw-r--r-- | drivers/block/drbd/drbd_actlog.c | 1248 |
1 files changed, 1248 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c new file mode 100644 index 000000000..5f0eaee8c --- /dev/null +++ b/drivers/block/drbd/drbd_actlog.c @@ -0,0 +1,1248 @@ +/* + drbd_actlog.c + + This file is part of DRBD by Philipp Reisner and Lars Ellenberg. + + Copyright (C) 2003-2008, LINBIT Information Technologies GmbH. + Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>. + Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@linbit.com>. + + drbd is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + drbd is distributed in the hope that 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. + + You should have received a copy of the GNU General Public License + along with drbd; see the file COPYING. If not, write to + the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + + */ + +#include <linux/slab.h> +#include <linux/crc32c.h> +#include <linux/drbd.h> +#include <linux/drbd_limits.h> +#include "drbd_int.h" + + +enum al_transaction_types { + AL_TR_UPDATE = 0, + AL_TR_INITIALIZED = 0xffff +}; +/* all fields on disc in big endian */ +struct __packed al_transaction_on_disk { + /* don't we all like magic */ + __be32 magic; + + /* to identify the most recent transaction block + * in the on disk ring buffer */ + __be32 tr_number; + + /* checksum on the full 4k block, with this field set to 0. */ + __be32 crc32c; + + /* type of transaction, special transaction types like: + * purge-all, set-all-idle, set-all-active, ... to-be-defined + * see also enum al_transaction_types */ + __be16 transaction_type; + + /* we currently allow only a few thousand extents, + * so 16bit will be enough for the slot number. */ + + /* how many updates in this transaction */ + __be16 n_updates; + + /* maximum slot number, "al-extents" in drbd.conf speak. + * Having this in each transaction should make reconfiguration + * of that parameter easier. */ + __be16 context_size; + + /* slot number the context starts with */ + __be16 context_start_slot_nr; + + /* Some reserved bytes. Expected usage is a 64bit counter of + * sectors-written since device creation, and other data generation tag + * supporting usage */ + __be32 __reserved[4]; + + /* --- 36 byte used --- */ + + /* Reserve space for up to AL_UPDATES_PER_TRANSACTION changes + * in one transaction, then use the remaining byte in the 4k block for + * context information. "Flexible" number of updates per transaction + * does not help, as we have to account for the case when all update + * slots are used anyways, so it would only complicate code without + * additional benefit. + */ + __be16 update_slot_nr[AL_UPDATES_PER_TRANSACTION]; + + /* but the extent number is 32bit, which at an extent size of 4 MiB + * allows to cover device sizes of up to 2**54 Byte (16 PiB) */ + __be32 update_extent_nr[AL_UPDATES_PER_TRANSACTION]; + + /* --- 420 bytes used (36 + 64*6) --- */ + + /* 4096 - 420 = 3676 = 919 * 4 */ + __be32 context[AL_CONTEXT_PER_TRANSACTION]; +}; + +void *drbd_md_get_buffer(struct drbd_device *device, const char *intent) +{ + int r; + + wait_event(device->misc_wait, + (r = atomic_cmpxchg(&device->md_io.in_use, 0, 1)) == 0 || + device->state.disk <= D_FAILED); + + if (r) + return NULL; + + device->md_io.current_use = intent; + device->md_io.start_jif = jiffies; + device->md_io.submit_jif = device->md_io.start_jif - 1; + return page_address(device->md_io.page); +} + +void drbd_md_put_buffer(struct drbd_device *device) +{ + if (atomic_dec_and_test(&device->md_io.in_use)) + wake_up(&device->misc_wait); +} + +void wait_until_done_or_force_detached(struct drbd_device *device, struct drbd_backing_dev *bdev, + unsigned int *done) +{ + long dt; + + rcu_read_lock(); + dt = rcu_dereference(bdev->disk_conf)->disk_timeout; + rcu_read_unlock(); + dt = dt * HZ / 10; + if (dt == 0) + dt = MAX_SCHEDULE_TIMEOUT; + + dt = wait_event_timeout(device->misc_wait, + *done || test_bit(FORCE_DETACH, &device->flags), dt); + if (dt == 0) { + drbd_err(device, "meta-data IO operation timed out\n"); + drbd_chk_io_error(device, 1, DRBD_FORCE_DETACH); + } +} + +static int _drbd_md_sync_page_io(struct drbd_device *device, + struct drbd_backing_dev *bdev, + sector_t sector, int op) +{ + struct bio *bio; + /* we do all our meta data IO in aligned 4k blocks. */ + const int size = 4096; + int err, op_flags = 0; + + device->md_io.done = 0; + device->md_io.error = -ENODEV; + + if ((op == REQ_OP_WRITE) && !test_bit(MD_NO_FUA, &device->flags)) + op_flags |= REQ_FUA | REQ_PREFLUSH; + op_flags |= REQ_SYNC; + + bio = bio_alloc_drbd(GFP_NOIO); + bio_set_dev(bio, bdev->md_bdev); + bio->bi_iter.bi_sector = sector; + err = -EIO; + if (bio_add_page(bio, device->md_io.page, size, 0) != size) + goto out; + bio->bi_private = device; + bio->bi_end_io = drbd_md_endio; + bio_set_op_attrs(bio, op, op_flags); + + if (op != REQ_OP_WRITE && device->state.disk == D_DISKLESS && device->ldev == NULL) + /* special case, drbd_md_read() during drbd_adm_attach(): no get_ldev */ + ; + else if (!get_ldev_if_state(device, D_ATTACHING)) { + /* Corresponding put_ldev in drbd_md_endio() */ + drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in _drbd_md_sync_page_io()\n"); + err = -ENODEV; + goto out; + } + + bio_get(bio); /* one bio_put() is in the completion handler */ + atomic_inc(&device->md_io.in_use); /* drbd_md_put_buffer() is in the completion handler */ + device->md_io.submit_jif = jiffies; + if (drbd_insert_fault(device, (op == REQ_OP_WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) + bio_io_error(bio); + else + submit_bio(bio); + wait_until_done_or_force_detached(device, bdev, &device->md_io.done); + if (!bio->bi_status) + err = device->md_io.error; + + out: + bio_put(bio); + return err; +} + +int drbd_md_sync_page_io(struct drbd_device *device, struct drbd_backing_dev *bdev, + sector_t sector, int op) +{ + int err; + D_ASSERT(device, atomic_read(&device->md_io.in_use) == 1); + + BUG_ON(!bdev->md_bdev); + + dynamic_drbd_dbg(device, "meta_data io: %s [%d]:%s(,%llus,%s) %pS\n", + current->comm, current->pid, __func__, + (unsigned long long)sector, (op == REQ_OP_WRITE) ? "WRITE" : "READ", + (void*)_RET_IP_ ); + + if (sector < drbd_md_first_sector(bdev) || + sector + 7 > drbd_md_last_sector(bdev)) + drbd_alert(device, "%s [%d]:%s(,%llus,%s) out of range md access!\n", + current->comm, current->pid, __func__, + (unsigned long long)sector, + (op == REQ_OP_WRITE) ? "WRITE" : "READ"); + + err = _drbd_md_sync_page_io(device, bdev, sector, op); + if (err) { + drbd_err(device, "drbd_md_sync_page_io(,%llus,%s) failed with error %d\n", + (unsigned long long)sector, + (op == REQ_OP_WRITE) ? "WRITE" : "READ", err); + } + return err; +} + +static struct bm_extent *find_active_resync_extent(struct drbd_device *device, unsigned int enr) +{ + struct lc_element *tmp; + tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT); + if (unlikely(tmp != NULL)) { + struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce); + if (test_bit(BME_NO_WRITES, &bm_ext->flags)) + return bm_ext; + } + return NULL; +} + +static struct lc_element *_al_get(struct drbd_device *device, unsigned int enr, bool nonblock) +{ + struct lc_element *al_ext; + struct bm_extent *bm_ext; + int wake; + + spin_lock_irq(&device->al_lock); + bm_ext = find_active_resync_extent(device, enr); + if (bm_ext) { + wake = !test_and_set_bit(BME_PRIORITY, &bm_ext->flags); + spin_unlock_irq(&device->al_lock); + if (wake) + wake_up(&device->al_wait); + return NULL; + } + if (nonblock) + al_ext = lc_try_get(device->act_log, enr); + else + al_ext = lc_get(device->act_log, enr); + spin_unlock_irq(&device->al_lock); + return al_ext; +} + +bool drbd_al_begin_io_fastpath(struct drbd_device *device, struct drbd_interval *i) +{ + /* for bios crossing activity log extent boundaries, + * we may need to activate two extents in one go */ + unsigned first = i->sector >> (AL_EXTENT_SHIFT-9); + unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9); + + D_ASSERT(device, first <= last); + D_ASSERT(device, atomic_read(&device->local_cnt) > 0); + + /* FIXME figure out a fast path for bios crossing AL extent boundaries */ + if (first != last) + return false; + + return _al_get(device, first, true); +} + +bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i) +{ + /* for bios crossing activity log extent boundaries, + * we may need to activate two extents in one go */ + unsigned first = i->sector >> (AL_EXTENT_SHIFT-9); + unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9); + unsigned enr; + bool need_transaction = false; + + D_ASSERT(device, first <= last); + D_ASSERT(device, atomic_read(&device->local_cnt) > 0); + + for (enr = first; enr <= last; enr++) { + struct lc_element *al_ext; + wait_event(device->al_wait, + (al_ext = _al_get(device, enr, false)) != NULL); + if (al_ext->lc_number != enr) + need_transaction = true; + } + return need_transaction; +} + +#if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT) +/* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT + * are still coupled, or assume too much about their relation. + * Code below will not work if this is violated. + * Will be cleaned up with some followup patch. + */ +# error FIXME +#endif + +static unsigned int al_extent_to_bm_page(unsigned int al_enr) +{ + return al_enr >> + /* bit to page */ + ((PAGE_SHIFT + 3) - + /* al extent number to bit */ + (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)); +} + +static sector_t al_tr_number_to_on_disk_sector(struct drbd_device *device) +{ + const unsigned int stripes = device->ldev->md.al_stripes; + const unsigned int stripe_size_4kB = device->ldev->md.al_stripe_size_4k; + + /* transaction number, modulo on-disk ring buffer wrap around */ + unsigned int t = device->al_tr_number % (device->ldev->md.al_size_4k); + + /* ... to aligned 4k on disk block */ + t = ((t % stripes) * stripe_size_4kB) + t/stripes; + + /* ... to 512 byte sector in activity log */ + t *= 8; + + /* ... plus offset to the on disk position */ + return device->ldev->md.md_offset + device->ldev->md.al_offset + t; +} + +static int __al_write_transaction(struct drbd_device *device, struct al_transaction_on_disk *buffer) +{ + struct lc_element *e; + sector_t sector; + int i, mx; + unsigned extent_nr; + unsigned crc = 0; + int err = 0; + + memset(buffer, 0, sizeof(*buffer)); + buffer->magic = cpu_to_be32(DRBD_AL_MAGIC); + buffer->tr_number = cpu_to_be32(device->al_tr_number); + + i = 0; + + drbd_bm_reset_al_hints(device); + + /* Even though no one can start to change this list + * once we set the LC_LOCKED -- from drbd_al_begin_io(), + * lc_try_lock_for_transaction() --, someone may still + * be in the process of changing it. */ + spin_lock_irq(&device->al_lock); + list_for_each_entry(e, &device->act_log->to_be_changed, list) { + if (i == AL_UPDATES_PER_TRANSACTION) { + i++; + break; + } + buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index); + buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number); + if (e->lc_number != LC_FREE) + drbd_bm_mark_for_writeout(device, + al_extent_to_bm_page(e->lc_number)); + i++; + } + spin_unlock_irq(&device->al_lock); + BUG_ON(i > AL_UPDATES_PER_TRANSACTION); + + buffer->n_updates = cpu_to_be16(i); + for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) { + buffer->update_slot_nr[i] = cpu_to_be16(-1); + buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE); + } + + buffer->context_size = cpu_to_be16(device->act_log->nr_elements); + buffer->context_start_slot_nr = cpu_to_be16(device->al_tr_cycle); + + mx = min_t(int, AL_CONTEXT_PER_TRANSACTION, + device->act_log->nr_elements - device->al_tr_cycle); + for (i = 0; i < mx; i++) { + unsigned idx = device->al_tr_cycle + i; + extent_nr = lc_element_by_index(device->act_log, idx)->lc_number; + buffer->context[i] = cpu_to_be32(extent_nr); + } + for (; i < AL_CONTEXT_PER_TRANSACTION; i++) + buffer->context[i] = cpu_to_be32(LC_FREE); + + device->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION; + if (device->al_tr_cycle >= device->act_log->nr_elements) + device->al_tr_cycle = 0; + + sector = al_tr_number_to_on_disk_sector(device); + + crc = crc32c(0, buffer, 4096); + buffer->crc32c = cpu_to_be32(crc); + + if (drbd_bm_write_hinted(device)) + err = -EIO; + else { + bool write_al_updates; + rcu_read_lock(); + write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates; + rcu_read_unlock(); + if (write_al_updates) { + if (drbd_md_sync_page_io(device, device->ldev, sector, WRITE)) { + err = -EIO; + drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR); + } else { + device->al_tr_number++; + device->al_writ_cnt++; + } + } + } + + return err; +} + +static int al_write_transaction(struct drbd_device *device) +{ + struct al_transaction_on_disk *buffer; + int err; + + if (!get_ldev(device)) { + drbd_err(device, "disk is %s, cannot start al transaction\n", + drbd_disk_str(device->state.disk)); + return -EIO; + } + + /* The bitmap write may have failed, causing a state change. */ + if (device->state.disk < D_INCONSISTENT) { + drbd_err(device, + "disk is %s, cannot write al transaction\n", + drbd_disk_str(device->state.disk)); + put_ldev(device); + return -EIO; + } + + /* protects md_io_buffer, al_tr_cycle, ... */ + buffer = drbd_md_get_buffer(device, __func__); + if (!buffer) { + drbd_err(device, "disk failed while waiting for md_io buffer\n"); + put_ldev(device); + return -ENODEV; + } + + err = __al_write_transaction(device, buffer); + + drbd_md_put_buffer(device); + put_ldev(device); + + return err; +} + + +void drbd_al_begin_io_commit(struct drbd_device *device) +{ + bool locked = false; + + /* Serialize multiple transactions. + * This uses test_and_set_bit, memory barrier is implicit. + */ + wait_event(device->al_wait, + device->act_log->pending_changes == 0 || + (locked = lc_try_lock_for_transaction(device->act_log))); + + if (locked) { + /* Double check: it may have been committed by someone else, + * while we have been waiting for the lock. */ + if (device->act_log->pending_changes) { + bool write_al_updates; + + rcu_read_lock(); + write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates; + rcu_read_unlock(); + + if (write_al_updates) + al_write_transaction(device); + spin_lock_irq(&device->al_lock); + /* FIXME + if (err) + we need an "lc_cancel" here; + */ + lc_committed(device->act_log); + spin_unlock_irq(&device->al_lock); + } + lc_unlock(device->act_log); + wake_up(&device->al_wait); + } +} + +/* + * @delegate: delegate activity log I/O to the worker thread + */ +void drbd_al_begin_io(struct drbd_device *device, struct drbd_interval *i) +{ + if (drbd_al_begin_io_prepare(device, i)) + drbd_al_begin_io_commit(device); +} + +int drbd_al_begin_io_nonblock(struct drbd_device *device, struct drbd_interval *i) +{ + struct lru_cache *al = device->act_log; + /* for bios crossing activity log extent boundaries, + * we may need to activate two extents in one go */ + unsigned first = i->sector >> (AL_EXTENT_SHIFT-9); + unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9); + unsigned nr_al_extents; + unsigned available_update_slots; + unsigned enr; + + D_ASSERT(device, first <= last); + + nr_al_extents = 1 + last - first; /* worst case: all touched extends are cold. */ + available_update_slots = min(al->nr_elements - al->used, + al->max_pending_changes - al->pending_changes); + + /* We want all necessary updates for a given request within the same transaction + * We could first check how many updates are *actually* needed, + * and use that instead of the worst-case nr_al_extents */ + if (available_update_slots < nr_al_extents) { + /* Too many activity log extents are currently "hot". + * + * If we have accumulated pending changes already, + * we made progress. + * + * If we cannot get even a single pending change through, + * stop the fast path until we made some progress, + * or requests to "cold" extents could be starved. */ + if (!al->pending_changes) + __set_bit(__LC_STARVING, &device->act_log->flags); + return -ENOBUFS; + } + + /* Is resync active in this area? */ + for (enr = first; enr <= last; enr++) { + struct lc_element *tmp; + tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT); + if (unlikely(tmp != NULL)) { + struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce); + if (test_bit(BME_NO_WRITES, &bm_ext->flags)) { + if (!test_and_set_bit(BME_PRIORITY, &bm_ext->flags)) + return -EBUSY; + return -EWOULDBLOCK; + } + } + } + + /* Checkout the refcounts. + * Given that we checked for available elements and update slots above, + * this has to be successful. */ + for (enr = first; enr <= last; enr++) { + struct lc_element *al_ext; + al_ext = lc_get_cumulative(device->act_log, enr); + if (!al_ext) + drbd_info(device, "LOGIC BUG for enr=%u\n", enr); + } + return 0; +} + +void drbd_al_complete_io(struct drbd_device *device, struct drbd_interval *i) +{ + /* for bios crossing activity log extent boundaries, + * we may need to activate two extents in one go */ + unsigned first = i->sector >> (AL_EXTENT_SHIFT-9); + unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9); + unsigned enr; + struct lc_element *extent; + unsigned long flags; + + D_ASSERT(device, first <= last); + spin_lock_irqsave(&device->al_lock, flags); + + for (enr = first; enr <= last; enr++) { + extent = lc_find(device->act_log, enr); + if (!extent) { + drbd_err(device, "al_complete_io() called on inactive extent %u\n", enr); + continue; + } + lc_put(device->act_log, extent); + } + spin_unlock_irqrestore(&device->al_lock, flags); + wake_up(&device->al_wait); +} + +static int _try_lc_del(struct drbd_device *device, struct lc_element *al_ext) +{ + int rv; + + spin_lock_irq(&device->al_lock); + rv = (al_ext->refcnt == 0); + if (likely(rv)) + lc_del(device->act_log, al_ext); + spin_unlock_irq(&device->al_lock); + + return rv; +} + +/** + * drbd_al_shrink() - Removes all active extents form the activity log + * @device: DRBD device. + * + * Removes all active extents form the activity log, waiting until + * the reference count of each entry dropped to 0 first, of course. + * + * You need to lock device->act_log with lc_try_lock() / lc_unlock() + */ +void drbd_al_shrink(struct drbd_device *device) +{ + struct lc_element *al_ext; + int i; + + D_ASSERT(device, test_bit(__LC_LOCKED, &device->act_log->flags)); + + for (i = 0; i < device->act_log->nr_elements; i++) { + al_ext = lc_element_by_index(device->act_log, i); + if (al_ext->lc_number == LC_FREE) + continue; + wait_event(device->al_wait, _try_lc_del(device, al_ext)); + } + + wake_up(&device->al_wait); +} + +int drbd_al_initialize(struct drbd_device *device, void *buffer) +{ + struct al_transaction_on_disk *al = buffer; + struct drbd_md *md = &device->ldev->md; + int al_size_4k = md->al_stripes * md->al_stripe_size_4k; + int i; + + __al_write_transaction(device, al); + /* There may or may not have been a pending transaction. */ + spin_lock_irq(&device->al_lock); + lc_committed(device->act_log); + spin_unlock_irq(&device->al_lock); + + /* The rest of the transactions will have an empty "updates" list, and + * are written out only to provide the context, and to initialize the + * on-disk ring buffer. */ + for (i = 1; i < al_size_4k; i++) { + int err = __al_write_transaction(device, al); + if (err) + return err; + } + return 0; +} + +static const char *drbd_change_sync_fname[] = { + [RECORD_RS_FAILED] = "drbd_rs_failed_io", + [SET_IN_SYNC] = "drbd_set_in_sync", + [SET_OUT_OF_SYNC] = "drbd_set_out_of_sync" +}; + +/* ATTENTION. The AL's extents are 4MB each, while the extents in the + * resync LRU-cache are 16MB each. + * The caller of this function has to hold an get_ldev() reference. + * + * Adjusts the caching members ->rs_left (success) or ->rs_failed (!success), + * potentially pulling in (and recounting the corresponding bits) + * this resync extent into the resync extent lru cache. + * + * Returns whether all bits have been cleared for this resync extent, + * precisely: (rs_left <= rs_failed) + * + * TODO will be obsoleted once we have a caching lru of the on disk bitmap + */ +static bool update_rs_extent(struct drbd_device *device, + unsigned int enr, int count, + enum update_sync_bits_mode mode) +{ + struct lc_element *e; + + D_ASSERT(device, atomic_read(&device->local_cnt)); + + /* When setting out-of-sync bits, + * we don't need it cached (lc_find). + * But if it is present in the cache, + * we should update the cached bit count. + * Otherwise, that extent should be in the resync extent lru cache + * already -- or we want to pull it in if necessary -- (lc_get), + * then update and check rs_left and rs_failed. */ + if (mode == SET_OUT_OF_SYNC) + e = lc_find(device->resync, enr); + else + e = lc_get(device->resync, enr); + if (e) { + struct bm_extent *ext = lc_entry(e, struct bm_extent, lce); + if (ext->lce.lc_number == enr) { + if (mode == SET_IN_SYNC) + ext->rs_left -= count; + else if (mode == SET_OUT_OF_SYNC) + ext->rs_left += count; + else + ext->rs_failed += count; + if (ext->rs_left < ext->rs_failed) { + drbd_warn(device, "BAD! enr=%u rs_left=%d " + "rs_failed=%d count=%d cstate=%s\n", + ext->lce.lc_number, ext->rs_left, + ext->rs_failed, count, + drbd_conn_str(device->state.conn)); + + /* We don't expect to be able to clear more bits + * than have been set when we originally counted + * the set bits to cache that value in ext->rs_left. + * Whatever the reason (disconnect during resync, + * delayed local completion of an application write), + * try to fix it up by recounting here. */ + ext->rs_left = drbd_bm_e_weight(device, enr); + } + } else { + /* Normally this element should be in the cache, + * since drbd_rs_begin_io() pulled it already in. + * + * But maybe an application write finished, and we set + * something outside the resync lru_cache in sync. + */ + int rs_left = drbd_bm_e_weight(device, enr); + if (ext->flags != 0) { + drbd_warn(device, "changing resync lce: %d[%u;%02lx]" + " -> %d[%u;00]\n", + ext->lce.lc_number, ext->rs_left, + ext->flags, enr, rs_left); + ext->flags = 0; + } + if (ext->rs_failed) { + drbd_warn(device, "Kicking resync_lru element enr=%u " + "out with rs_failed=%d\n", + ext->lce.lc_number, ext->rs_failed); + } + ext->rs_left = rs_left; + ext->rs_failed = (mode == RECORD_RS_FAILED) ? count : 0; + /* we don't keep a persistent log of the resync lru, + * we can commit any change right away. */ + lc_committed(device->resync); + } + if (mode != SET_OUT_OF_SYNC) + lc_put(device->resync, &ext->lce); + /* no race, we are within the al_lock! */ + + if (ext->rs_left <= ext->rs_failed) { + ext->rs_failed = 0; + return true; + } + } else if (mode != SET_OUT_OF_SYNC) { + /* be quiet if lc_find() did not find it. */ + drbd_err(device, "lc_get() failed! locked=%d/%d flags=%lu\n", + device->resync_locked, + device->resync->nr_elements, + device->resync->flags); + } + return false; +} + +void drbd_advance_rs_marks(struct drbd_device *device, unsigned long still_to_go) +{ + unsigned long now = jiffies; + unsigned long last = device->rs_mark_time[device->rs_last_mark]; + int next = (device->rs_last_mark + 1) % DRBD_SYNC_MARKS; + if (time_after_eq(now, last + DRBD_SYNC_MARK_STEP)) { + if (device->rs_mark_left[device->rs_last_mark] != still_to_go && + device->state.conn != C_PAUSED_SYNC_T && + device->state.conn != C_PAUSED_SYNC_S) { + device->rs_mark_time[next] = now; + device->rs_mark_left[next] = still_to_go; + device->rs_last_mark = next; + } + } +} + +/* It is called lazy update, so don't do write-out too often. */ +static bool lazy_bitmap_update_due(struct drbd_device *device) +{ + return time_after(jiffies, device->rs_last_bcast + 2*HZ); +} + +static void maybe_schedule_on_disk_bitmap_update(struct drbd_device *device, bool rs_done) +{ + if (rs_done) { + struct drbd_connection *connection = first_peer_device(device)->connection; + if (connection->agreed_pro_version <= 95 || + is_sync_target_state(device->state.conn)) + set_bit(RS_DONE, &device->flags); + /* and also set RS_PROGRESS below */ + + /* Else: rather wait for explicit notification via receive_state, + * to avoid uuids-rotated-too-fast causing full resync + * in next handshake, in case the replication link breaks + * at the most unfortunate time... */ + } else if (!lazy_bitmap_update_due(device)) + return; + + drbd_device_post_work(device, RS_PROGRESS); +} + +static int update_sync_bits(struct drbd_device *device, + unsigned long sbnr, unsigned long ebnr, + enum update_sync_bits_mode mode) +{ + /* + * We keep a count of set bits per resync-extent in the ->rs_left + * caching member, so we need to loop and work within the resync extent + * alignment. Typically this loop will execute exactly once. + */ + unsigned long flags; + unsigned long count = 0; + unsigned int cleared = 0; + while (sbnr <= ebnr) { + /* set temporary boundary bit number to last bit number within + * the resync extent of the current start bit number, + * but cap at provided end bit number */ + unsigned long tbnr = min(ebnr, sbnr | BM_BLOCKS_PER_BM_EXT_MASK); + unsigned long c; + + if (mode == RECORD_RS_FAILED) + /* Only called from drbd_rs_failed_io(), bits + * supposedly still set. Recount, maybe some + * of the bits have been successfully cleared + * by application IO meanwhile. + */ + c = drbd_bm_count_bits(device, sbnr, tbnr); + else if (mode == SET_IN_SYNC) + c = drbd_bm_clear_bits(device, sbnr, tbnr); + else /* if (mode == SET_OUT_OF_SYNC) */ + c = drbd_bm_set_bits(device, sbnr, tbnr); + + if (c) { + spin_lock_irqsave(&device->al_lock, flags); + cleared += update_rs_extent(device, BM_BIT_TO_EXT(sbnr), c, mode); + spin_unlock_irqrestore(&device->al_lock, flags); + count += c; + } + sbnr = tbnr + 1; + } + if (count) { + if (mode == SET_IN_SYNC) { + unsigned long still_to_go = drbd_bm_total_weight(device); + bool rs_is_done = (still_to_go <= device->rs_failed); + drbd_advance_rs_marks(device, still_to_go); + if (cleared || rs_is_done) + maybe_schedule_on_disk_bitmap_update(device, rs_is_done); + } else if (mode == RECORD_RS_FAILED) + device->rs_failed += count; + wake_up(&device->al_wait); + } + return count; +} + +static bool plausible_request_size(int size) +{ + return size > 0 + && size <= DRBD_MAX_BATCH_BIO_SIZE + && IS_ALIGNED(size, 512); +} + +/* clear the bit corresponding to the piece of storage in question: + * size byte of data starting from sector. Only clear a bits of the affected + * one ore more _aligned_ BM_BLOCK_SIZE blocks. + * + * called by worker on C_SYNC_TARGET and receiver on SyncSource. + * + */ +int __drbd_change_sync(struct drbd_device *device, sector_t sector, int size, + enum update_sync_bits_mode mode) +{ + /* Is called from worker and receiver context _only_ */ + unsigned long sbnr, ebnr, lbnr; + unsigned long count = 0; + sector_t esector, nr_sectors; + + /* This would be an empty REQ_PREFLUSH, be silent. */ + if ((mode == SET_OUT_OF_SYNC) && size == 0) + return 0; + + if (!plausible_request_size(size)) { + drbd_err(device, "%s: sector=%llus size=%d nonsense!\n", + drbd_change_sync_fname[mode], + (unsigned long long)sector, size); + return 0; + } + + if (!get_ldev(device)) + return 0; /* no disk, no metadata, no bitmap to manipulate bits in */ + + nr_sectors = drbd_get_capacity(device->this_bdev); + esector = sector + (size >> 9) - 1; + + if (!expect(sector < nr_sectors)) + goto out; + if (!expect(esector < nr_sectors)) + esector = nr_sectors - 1; + + lbnr = BM_SECT_TO_BIT(nr_sectors-1); + + if (mode == SET_IN_SYNC) { + /* Round up start sector, round down end sector. We make sure + * we only clear full, aligned, BM_BLOCK_SIZE blocks. */ + if (unlikely(esector < BM_SECT_PER_BIT-1)) + goto out; + if (unlikely(esector == (nr_sectors-1))) + ebnr = lbnr; + else + ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1)); + sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1); + } else { + /* We set it out of sync, or record resync failure. + * Should not round anything here. */ + sbnr = BM_SECT_TO_BIT(sector); + ebnr = BM_SECT_TO_BIT(esector); + } + + count = update_sync_bits(device, sbnr, ebnr, mode); +out: + put_ldev(device); + return count; +} + +static +struct bm_extent *_bme_get(struct drbd_device *device, unsigned int enr) +{ + struct lc_element *e; + struct bm_extent *bm_ext; + int wakeup = 0; + unsigned long rs_flags; + + spin_lock_irq(&device->al_lock); + if (device->resync_locked > device->resync->nr_elements/2) { + spin_unlock_irq(&device->al_lock); + return NULL; + } + e = lc_get(device->resync, enr); + bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL; + if (bm_ext) { + if (bm_ext->lce.lc_number != enr) { + bm_ext->rs_left = drbd_bm_e_weight(device, enr); + bm_ext->rs_failed = 0; + lc_committed(device->resync); + wakeup = 1; + } + if (bm_ext->lce.refcnt == 1) + device->resync_locked++; + set_bit(BME_NO_WRITES, &bm_ext->flags); + } + rs_flags = device->resync->flags; + spin_unlock_irq(&device->al_lock); + if (wakeup) + wake_up(&device->al_wait); + + if (!bm_ext) { + if (rs_flags & LC_STARVING) + drbd_warn(device, "Have to wait for element" + " (resync LRU too small?)\n"); + BUG_ON(rs_flags & LC_LOCKED); + } + + return bm_ext; +} + +static int _is_in_al(struct drbd_device *device, unsigned int enr) +{ + int rv; + + spin_lock_irq(&device->al_lock); + rv = lc_is_used(device->act_log, enr); + spin_unlock_irq(&device->al_lock); + + return rv; +} + +/** + * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED + * @device: DRBD device. + * @sector: The sector number. + * + * This functions sleeps on al_wait. Returns 0 on success, -EINTR if interrupted. + */ +int drbd_rs_begin_io(struct drbd_device *device, sector_t sector) +{ + unsigned int enr = BM_SECT_TO_EXT(sector); + struct bm_extent *bm_ext; + int i, sig; + bool sa; + +retry: + sig = wait_event_interruptible(device->al_wait, + (bm_ext = _bme_get(device, enr))); + if (sig) + return -EINTR; + + if (test_bit(BME_LOCKED, &bm_ext->flags)) + return 0; + + /* step aside only while we are above c-min-rate; unless disabled. */ + sa = drbd_rs_c_min_rate_throttle(device); + + for (i = 0; i < AL_EXT_PER_BM_SECT; i++) { + sig = wait_event_interruptible(device->al_wait, + !_is_in_al(device, enr * AL_EXT_PER_BM_SECT + i) || + (sa && test_bit(BME_PRIORITY, &bm_ext->flags))); + + if (sig || (sa && test_bit(BME_PRIORITY, &bm_ext->flags))) { + spin_lock_irq(&device->al_lock); + if (lc_put(device->resync, &bm_ext->lce) == 0) { + bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */ + device->resync_locked--; + wake_up(&device->al_wait); + } + spin_unlock_irq(&device->al_lock); + if (sig) + return -EINTR; + if (schedule_timeout_interruptible(HZ/10)) + return -EINTR; + goto retry; + } + } + set_bit(BME_LOCKED, &bm_ext->flags); + return 0; +} + +/** + * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep + * @device: DRBD device. + * @sector: The sector number. + * + * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then + * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN + * if there is still application IO going on in this area. + */ +int drbd_try_rs_begin_io(struct drbd_device *device, sector_t sector) +{ + unsigned int enr = BM_SECT_TO_EXT(sector); + const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT; + struct lc_element *e; + struct bm_extent *bm_ext; + int i; + bool throttle = drbd_rs_should_slow_down(device, sector, true); + + /* If we need to throttle, a half-locked (only marked BME_NO_WRITES, + * not yet BME_LOCKED) extent needs to be kicked out explicitly if we + * need to throttle. There is at most one such half-locked extent, + * which is remembered in resync_wenr. */ + + if (throttle && device->resync_wenr != enr) + return -EAGAIN; + + spin_lock_irq(&device->al_lock); + if (device->resync_wenr != LC_FREE && device->resync_wenr != enr) { + /* in case you have very heavy scattered io, it may + * stall the syncer undefined if we give up the ref count + * when we try again and requeue. + * + * if we don't give up the refcount, but the next time + * we are scheduled this extent has been "synced" by new + * application writes, we'd miss the lc_put on the + * extent we keep the refcount on. + * so we remembered which extent we had to try again, and + * if the next requested one is something else, we do + * the lc_put here... + * we also have to wake_up + */ + e = lc_find(device->resync, device->resync_wenr); + bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL; + if (bm_ext) { + D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags)); + D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags)); + clear_bit(BME_NO_WRITES, &bm_ext->flags); + device->resync_wenr = LC_FREE; + if (lc_put(device->resync, &bm_ext->lce) == 0) { + bm_ext->flags = 0; + device->resync_locked--; + } + wake_up(&device->al_wait); + } else { + drbd_alert(device, "LOGIC BUG\n"); + } + } + /* TRY. */ + e = lc_try_get(device->resync, enr); + bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL; + if (bm_ext) { + if (test_bit(BME_LOCKED, &bm_ext->flags)) + goto proceed; + if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) { + device->resync_locked++; + } else { + /* we did set the BME_NO_WRITES, + * but then could not set BME_LOCKED, + * so we tried again. + * drop the extra reference. */ + bm_ext->lce.refcnt--; + D_ASSERT(device, bm_ext->lce.refcnt > 0); + } + goto check_al; + } else { + /* do we rather want to try later? */ + if (device->resync_locked > device->resync->nr_elements-3) + goto try_again; + /* Do or do not. There is no try. -- Yoda */ + e = lc_get(device->resync, enr); + bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL; + if (!bm_ext) { + const unsigned long rs_flags = device->resync->flags; + if (rs_flags & LC_STARVING) + drbd_warn(device, "Have to wait for element" + " (resync LRU too small?)\n"); + BUG_ON(rs_flags & LC_LOCKED); + goto try_again; + } + if (bm_ext->lce.lc_number != enr) { + bm_ext->rs_left = drbd_bm_e_weight(device, enr); + bm_ext->rs_failed = 0; + lc_committed(device->resync); + wake_up(&device->al_wait); + D_ASSERT(device, test_bit(BME_LOCKED, &bm_ext->flags) == 0); + } + set_bit(BME_NO_WRITES, &bm_ext->flags); + D_ASSERT(device, bm_ext->lce.refcnt == 1); + device->resync_locked++; + goto check_al; + } +check_al: + for (i = 0; i < AL_EXT_PER_BM_SECT; i++) { + if (lc_is_used(device->act_log, al_enr+i)) + goto try_again; + } + set_bit(BME_LOCKED, &bm_ext->flags); +proceed: + device->resync_wenr = LC_FREE; + spin_unlock_irq(&device->al_lock); + return 0; + +try_again: + if (bm_ext) { + if (throttle) { + D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags)); + D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags)); + clear_bit(BME_NO_WRITES, &bm_ext->flags); + device->resync_wenr = LC_FREE; + if (lc_put(device->resync, &bm_ext->lce) == 0) { + bm_ext->flags = 0; + device->resync_locked--; + } + wake_up(&device->al_wait); + } else + device->resync_wenr = enr; + } + spin_unlock_irq(&device->al_lock); + return -EAGAIN; +} + +void drbd_rs_complete_io(struct drbd_device *device, sector_t sector) +{ + unsigned int enr = BM_SECT_TO_EXT(sector); + struct lc_element *e; + struct bm_extent *bm_ext; + unsigned long flags; + + spin_lock_irqsave(&device->al_lock, flags); + e = lc_find(device->resync, enr); + bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL; + if (!bm_ext) { + spin_unlock_irqrestore(&device->al_lock, flags); + if (__ratelimit(&drbd_ratelimit_state)) + drbd_err(device, "drbd_rs_complete_io() called, but extent not found\n"); + return; + } + + if (bm_ext->lce.refcnt == 0) { + spin_unlock_irqrestore(&device->al_lock, flags); + drbd_err(device, "drbd_rs_complete_io(,%llu [=%u]) called, " + "but refcnt is 0!?\n", + (unsigned long long)sector, enr); + return; + } + + if (lc_put(device->resync, &bm_ext->lce) == 0) { + bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */ + device->resync_locked--; + wake_up(&device->al_wait); + } + + spin_unlock_irqrestore(&device->al_lock, flags); +} + +/** + * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED) + * @device: DRBD device. + */ +void drbd_rs_cancel_all(struct drbd_device *device) +{ + spin_lock_irq(&device->al_lock); + + if (get_ldev_if_state(device, D_FAILED)) { /* Makes sure ->resync is there. */ + lc_reset(device->resync); + put_ldev(device); + } + device->resync_locked = 0; + device->resync_wenr = LC_FREE; + spin_unlock_irq(&device->al_lock); + wake_up(&device->al_wait); +} + +/** + * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU + * @device: DRBD device. + * + * Returns 0 upon success, -EAGAIN if at least one reference count was + * not zero. + */ +int drbd_rs_del_all(struct drbd_device *device) +{ + struct lc_element *e; + struct bm_extent *bm_ext; + int i; + + spin_lock_irq(&device->al_lock); + + if (get_ldev_if_state(device, D_FAILED)) { + /* ok, ->resync is there. */ + for (i = 0; i < device->resync->nr_elements; i++) { + e = lc_element_by_index(device->resync, i); + bm_ext = lc_entry(e, struct bm_extent, lce); + if (bm_ext->lce.lc_number == LC_FREE) + continue; + if (bm_ext->lce.lc_number == device->resync_wenr) { + drbd_info(device, "dropping %u in drbd_rs_del_all, apparently" + " got 'synced' by application io\n", + device->resync_wenr); + D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags)); + D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags)); + clear_bit(BME_NO_WRITES, &bm_ext->flags); + device->resync_wenr = LC_FREE; + lc_put(device->resync, &bm_ext->lce); + } + if (bm_ext->lce.refcnt != 0) { + drbd_info(device, "Retrying drbd_rs_del_all() later. " + "refcnt=%d\n", bm_ext->lce.refcnt); + put_ldev(device); + spin_unlock_irq(&device->al_lock); + return -EAGAIN; + } + D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags)); + D_ASSERT(device, !test_bit(BME_NO_WRITES, &bm_ext->flags)); + lc_del(device->resync, &bm_ext->lce); + } + D_ASSERT(device, device->resync->used == 0); + put_ldev(device); + } + spin_unlock_irq(&device->al_lock); + wake_up(&device->al_wait); + + return 0; +} |