// SPDX-License-Identifier: GPL-2.0-only
/*
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 <[email protected]>.
Copyright (C) 2003-2008, Lars Ellenberg <[email protected]>.
*/
#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, enum req_op op)
{
struct bio *bio;
/* we do all our meta data IO in aligned 4k blocks. */
const int size = 4096;
int err;
blk_opf_t 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_bioset(bdev->md_bdev, 1, op | op_flags, GFP_NOIO,
&drbd_md_io_bio_set);
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;
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, enum req_op 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, REQ_OP_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_peer_device *peer_device, unsigned long still_to_go)
{
struct drbd_device *device = peer_device->device;
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(first_peer_device(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 bits of the affected
* one or more _aligned_ BM_BLOCK_SIZE blocks.
*
* called by worker on C_SYNC_TARGET and receiver on SyncSource.
*
*/
int __drbd_change_sync(struct drbd_peer_device *peer_device, sector_t sector, int size,
enum update_sync_bits_mode mode)
{
/* Is called from worker and receiver context _only_ */
struct drbd_device *device = peer_device->device;
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 = get_capacity(device->vdisk);
esector = sector + (size >> 9) - 1;
if (!expect(device, sector < nr_sectors))
goto out;
if (!expect(device, 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
* @peer_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_peer_device *peer_device, sector_t sector)
{
struct drbd_device *device = peer_device->device;
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(peer_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 (drbd_ratelimit())
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;
}
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