/* 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 . Copyright (C) 2003-2008, Lars Ellenberg . 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 #include #include #include #include #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 | REQ_NOIDLE; bio = bio_alloc_drbd(GFP_NOIO); bio->bi_bdev = 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_error) 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; /* 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) set_bit(RS_DONE, &device->flags); /* and also set RS_PROGRESS below */ 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; } /* 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 (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_DISCARD_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; }