--- /dev/null
+/*
+ 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 <linux/dynamic_debug.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 rw)
+{
+ struct bio *bio;
+ /* we do all our meta data IO in aligned 4k blocks. */
+ const int size = 4096;
+ int err;
+
+ device->md_io.done = 0;
+ device->md_io.error = -ENODEV;
+
+ if ((rw & WRITE) && !test_bit(MD_NO_FUA, &device->flags))
+ rw |= REQ_FUA | REQ_FLUSH;
+ rw |= 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->bi_rw = rw;
+
+ if (!(rw & 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, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
+ bio_endio(bio, -EIO);
+ else
+ submit_bio(rw, bio);
+ wait_until_done_or_force_detached(device, bdev, &device->md_io.done);
+ if (bio_flagged(bio, BIO_UPTODATE))
+ 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 rw)
+{
+ 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, (rw & 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, (rw & WRITE) ? "WRITE" : "READ");
+
+ err = _drbd_md_sync_page_io(device, bdev, sector, rw);
+ if (err) {
+ drbd_err(device, "drbd_md_sync_page_io(,%llus,%s) failed with error %d\n",
+ (unsigned long long)sector, (rw & 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, (unsigned)(last - first) <= 1);
+ 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;
+}
+
+static int al_write_transaction(struct drbd_device *device);
+
+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);
+}
+
+#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;
+}
+
+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;
+
+ 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;
+ }
+
+ 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++;
+ }
+ }
+ }
+
+ drbd_md_put_buffer(device);
+ put_ldev(device);
+
+ return err;
+}
+
+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_initialize_al(struct drbd_device *device, void *buffer)
+{
+ struct al_transaction_on_disk *al = buffer;
+ struct drbd_md *md = &device->ldev->md;
+ sector_t al_base = md->md_offset + md->al_offset;
+ int al_size_4k = md->al_stripes * md->al_stripe_size_4k;
+ int i;
+
+ memset(al, 0, 4096);
+ al->magic = cpu_to_be32(DRBD_AL_MAGIC);
+ al->transaction_type = cpu_to_be16(AL_TR_INITIALIZED);
+ al->crc32c = cpu_to_be32(crc32c(0, al, 4096));
+
+ for (i = 0; i < al_size_4k; i++) {
+ int err = drbd_md_sync_page_io(device, device->ldev, al_base + i * 8, WRITE);
+ 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_FLUSH, 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;
+}
Code Review / kvmfornfv.git / blobdiff