- 根目录:
- drivers
- md
- bcache
- journal.c
/*
* bcache journalling code, for btree insertions
*
* Copyright 2012 Google, Inc.
*/
#include "bcache.h"
#include "btree.h"
#include "debug.h"
#include "request.h"
/*
* Journal replay/recovery:
*
* This code is all driven from run_cache_set(); we first read the journal
* entries, do some other stuff, then we mark all the keys in the journal
* entries (same as garbage collection would), then we replay them - reinserting
* them into the cache in precisely the same order as they appear in the
* journal.
*
* We only journal keys that go in leaf nodes, which simplifies things quite a
* bit.
*/
static void journal_read_endio(struct bio *bio, int error)
{
struct closure *cl = bio->bi_private;
closure_put(cl);
}
static int journal_read_bucket(struct cache *ca, struct list_head *list,
struct btree_op *op, unsigned bucket_index)
{
struct journal_device *ja = &ca->journal;
struct bio *bio = &ja->bio;
struct journal_replay *i;
struct jset *j, *data = ca->set->journal.w[0].data;
unsigned len, left, offset = 0;
int ret = 0;
sector_t bucket = bucket_to_sector(ca->set, ca->sb.d[bucket_index]);
pr_debug("reading %llu", (uint64_t) bucket);
while (offset < ca->sb.bucket_size) {
reread: left = ca->sb.bucket_size - offset;
len = min_t(unsigned, left, PAGE_SECTORS * 8);
bio_reset(bio);
bio->bi_sector = bucket + offset;
bio->bi_bdev = ca->bdev;
bio->bi_rw = READ;
bio->bi_size = len << 9;
bio->bi_end_io = journal_read_endio;
bio->bi_private = &op->cl;
bch_bio_map(bio, data);
closure_bio_submit(bio, &op->cl, ca);
closure_sync(&op->cl);
/* This function could be simpler now since we no longer write
* journal entries that overlap bucket boundaries; this means
* the start of a bucket will always have a valid journal entry
* if it has any journal entries at all.
*/
j = data;
while (len) {
struct list_head *where;
size_t blocks, bytes = set_bytes(j);
if (j->magic != jset_magic(ca->set))
return ret;
if (bytes > left << 9)
return ret;
if (bytes > len << 9)
goto reread;
if (j->csum != csum_set(j))
return ret;
blocks = set_blocks(j, ca->set);
while (!list_empty(list)) {
i = list_first_entry(list,
struct journal_replay, list);
if (i->j.seq >= j->last_seq)
break;
list_del(&i->list);
kfree(i);
}
list_for_each_entry_reverse(i, list, list) {
if (j->seq == i->j.seq)
goto next_set;
if (j->seq < i->j.last_seq)
goto next_set;
if (j->seq > i->j.seq) {
where = &i->list;
goto add;
}
}
where = list;
add:
i = kmalloc(offsetof(struct journal_replay, j) +
bytes, GFP_KERNEL);
if (!i)
return -ENOMEM;
memcpy(&i->j, j, bytes);
list_add(&i->list, where);
ret = 1;
ja->seq[bucket_index] = j->seq;
next_set:
offset += blocks * ca->sb.block_size;
len -= blocks * ca->sb.block_size;
j = ((void *) j) + blocks * block_bytes(ca);
}
}
return ret;
}
int bch_journal_read(struct cache_set *c, struct list_head *list,
struct btree_op *op)
{
#define read_bucket(b) \
({ \
int ret = journal_read_bucket(ca, list, op, b); \
__set_bit(b, bitmap); \
if (ret < 0) \
return ret; \
ret; \
})
struct cache *ca;
unsigned iter;
for_each_cache(ca, c, iter) {
struct journal_device *ja = &ca->journal;
unsigned long bitmap[SB_JOURNAL_BUCKETS / BITS_PER_LONG];
unsigned i, l, r, m;
uint64_t seq;
bitmap_zero(bitmap, SB_JOURNAL_BUCKETS);
pr_debug("%u journal buckets", ca->sb.njournal_buckets);
/* Read journal buckets ordered by golden ratio hash to quickly
* find a sequence of buckets with valid journal entries
*/
for (i = 0; i < ca->sb.njournal_buckets; i++) {
l = (i * 2654435769U) % ca->sb.njournal_buckets;
if (test_bit(l, bitmap))
break;
if (read_bucket(l))
goto bsearch;
}
/* If that fails, check all the buckets we haven't checked
* already
*/
pr_debug("falling back to linear search");
for (l = 0; l < ca->sb.njournal_buckets; l++) {
if (test_bit(l, bitmap))
continue;
if (read_bucket(l))
goto bsearch;
}
bsearch:
/* Binary search */
m = r = find_next_bit(bitmap, ca->sb.njournal_buckets, l + 1);
pr_debug("starting binary search, l %u r %u", l, r);
while (l + 1 < r) {
m = (l + r) >> 1;
if (read_bucket(m))
l = m;
else
r = m;
}
/* Read buckets in reverse order until we stop finding more
* journal entries
*/
pr_debug("finishing up");
l = m;
while (1) {
if (!l--)
l = ca->sb.njournal_buckets - 1;
if (l == m)
break;
if (test_bit(l, bitmap))
continue;
if (!read_bucket(l))
break;
}
seq = 0;
for (i = 0; i < ca->sb.njournal_buckets; i++)
if (ja->seq[i] > seq) {
seq = ja->seq[i];
ja->cur_idx = ja->discard_idx =
ja->last_idx = i;
}
}
c->journal.seq = list_entry(list->prev,
struct journal_replay,
list)->j.seq;
return 0;
#undef read_bucket
}
void bch_journal_mark(struct cache_set *c, struct list_head *list)
{
atomic_t p = { 0 };
struct bkey *k;
struct journal_replay *i;
struct journal *j = &c->journal;
uint64_t last = j->seq;
/*
* journal.pin should never fill up - we never write a journal
* entry when it would fill up. But if for some reason it does, we
* iterate over the list in reverse order so that we can just skip that
* refcount instead of bugging.
*/
list_for_each_entry_reverse(i, list, list) {
BUG_ON(last < i->j.seq);
i->pin = NULL;
while (last-- != i->j.seq)
if (fifo_free(&j->pin) > 1) {
fifo_push_front(&j->pin, p);
atomic_set(&fifo_front(&j->pin), 0);
}
if (fifo_free(&j->pin) > 1) {
fifo_push_front(&j->pin, p);
i->pin = &fifo_front(&j->pin);
atomic_set(i->pin, 1);
}
for (k = i->j.start;
k < end(&i->j);
k = bkey_next(k)) {
unsigned j;
for (j = 0; j < KEY_PTRS(k); j++) {
struct bucket *g = PTR_BUCKET(c, k, j);
atomic_inc(&g->pin);
if (g->prio == BTREE_PRIO &&
!ptr_stale(c, k, j))
g->prio = INITIAL_PRIO;
}
__bch_btree_mark_key(c, 0, k);
}
}
}
int bch_journal_replay(struct cache_set *s, struct list_head *list,
struct btree_op *op)
{
int ret = 0, keys = 0, entries = 0;
struct bkey *k;
struct journal_replay *i =
list_entry(list->prev, struct journal_replay, list);
uint64_t start = i->j.last_seq, end = i->j.seq, n = start;
list_for_each_entry(i, list, list) {
BUG_ON(i->pin && atomic_read(i->pin) != 1);
if (n != i->j.seq)
pr_err(
"journal entries %llu-%llu missing! (replaying %llu-%llu)\n",
n, i->j.seq - 1, start, end);
for (k = i->j.start;
k < end(&i->j);
k = bkey_next(k)) {
pr_debug("%s", pkey(k));
bkey_copy(op->keys.top, k);
bch_keylist_push(&op->keys);
op->journal = i->pin;
atomic_inc(op->journal);
ret = bch_btree_insert(op, s);
if (ret)
goto err;
BUG_ON(!bch_keylist_empty(&op->keys));
keys++;
cond_resched();
}
if (i->pin)
atomic_dec(i->pin);
n = i->j.seq + 1;
entries++;
}
pr_info("journal replay done, %i keys in %i entries, seq %llu",
keys, entries, end);
while (!list_empty(list)) {
i = list_first_entry(list, struct journal_replay, list);
list_del(&i->list);
kfree(i);
}
err:
closure_sync(&op->cl);
return ret;
}
/* Journalling */
static void btree_flush_write(struct cache_set *c)
{
/*
* Try to find the btree node with that references the oldest journal
* entry, best is our current candidate and is locked if non NULL:
*/
struct btree *b, *best = NULL;
unsigned iter;
for_each_cached_btree(b, c, iter) {
if (!down_write_trylock(&b->lock))
continue;
if (!btree_node_dirty(b) ||
!btree_current_write(b)->journal) {
rw_unlock(true, b);
continue;
}
if (!best)
best = b;
else if (journal_pin_cmp(c,
btree_current_write(best),
btree_current_write(b))) {
rw_unlock(true, best);
best = b;
} else
rw_unlock(true, b);
}
if (best)
goto out;
/* We can't find the best btree node, just pick the first */
list_for_each_entry(b, &c->btree_cache, list)
if (!b->level && btree_node_dirty(b)) {
best = b;
rw_lock(true, best, best->level);
goto found;
}
out:
if (!best)
return;
found:
if (btree_node_dirty(best))
bch_btree_write(best, true, NULL);
rw_unlock(true, best);
}
#define last_seq(j) ((j)->seq - fifo_used(&(j)->pin) + 1)
static void journal_discard_endio(struct bio *bio, int error)
{
struct journal_device *ja =
container_of(bio, struct journal_device, discard_bio);
struct cache *ca = container_of(ja, struct cache, journal);
atomic_set(&ja->discard_in_flight, DISCARD_DONE);
closure_wake_up(&ca->set->journal.wait);
closure_put(&ca->set->cl);
}
static void journal_discard_work(struct work_struct *work)
{
struct journal_device *ja =
container_of(work, struct journal_device, discard_work);
submit_bio(0, &ja->discard_bio);
}
static void do_journal_discard(struct cache *ca)
{
struct journal_device *ja = &ca->journal;
struct bio *bio = &ja->discard_bio;
if (!ca->discard) {
ja->discard_idx = ja->last_idx;
return;
}
switch (atomic_read(&ja->discard_in_flight) == DISCARD_IN_FLIGHT) {
case DISCARD_IN_FLIGHT:
return;
case DISCARD_DONE:
ja->discard_idx = (ja->discard_idx + 1) %
ca->sb.njournal_buckets;
atomic_set(&ja->discard_in_flight, DISCARD_READY);
/* fallthrough */
case DISCARD_READY:
if (ja->discard_idx == ja->last_idx)
return;
atomic_set(&ja->discard_in_flight, DISCARD_IN_FLIGHT);
bio_init(bio);
bio->bi_sector = bucket_to_sector(ca->set,
ca->sb.d[ja->discard_idx]);
bio->bi_bdev = ca->bdev;
bio->bi_rw = REQ_WRITE|REQ_DISCARD;
bio->bi_max_vecs = 1;
bio->bi_io_vec = bio->bi_inline_vecs;
bio->bi_size = bucket_bytes(ca);
bio->bi_end_io = journal_discard_endio;
closure_get(&ca->set->cl);
INIT_WORK(&ja->discard_work, journal_discard_work);
schedule_work(&ja->discard_work);
}
}
static void journal_reclaim(struct cache_set *c)
{
struct bkey *k = &c->journal.key;
struct cache *ca;
uint64_t last_seq;
unsigned iter, n = 0;
atomic_t p;
while (!atomic_read(&fifo_front(&c->journal.pin)))
fifo_pop(&c->journal.pin, p);
last_seq = last_seq(&c->journal);
/* Update last_idx */
for_each_cache(ca, c, iter) {
struct journal_device *ja = &ca->journal;
while (ja->last_idx != ja->cur_idx &&
ja->seq[ja->last_idx] < last_seq)
ja->last_idx = (ja->last_idx + 1) %
ca->sb.njournal_buckets;
}
for_each_cache(ca, c, iter)
do_journal_discard(ca);
if (c->journal.blocks_free)
return;
/*
* Allocate:
* XXX: Sort by free journal space
*/
for_each_cache(ca, c, iter) {
struct journal_device *ja = &ca->journal;
unsigned next = (ja->cur_idx + 1) % ca->sb.njournal_buckets;
/* No space available on this device */
if (next == ja->discard_idx)
continue;
ja->cur_idx = next;
k->ptr[n++] = PTR(0,
bucket_to_sector(c, ca->sb.d[ja->cur_idx]),
ca->sb.nr_this_dev);
}
bkey_init(k);
SET_KEY_PTRS(k, n);
if (n)
c->journal.blocks_free = c->sb.bucket_size >> c->block_bits;
if (!journal_full(&c->journal))
__closure_wake_up(&c->journal.wait);
}
void bch_journal_next(struct journal *j)
{
atomic_t p = { 1 };
j->cur = (j->cur == j->w)
? &j->w[1]
: &j->w[0];
/*
* The fifo_push() needs to happen at the same time as j->seq is
* incremented for last_seq() to be calculated correctly
*/
BUG_ON(!fifo_push(&j->pin, p));
atomic_set(&fifo_back(&j->pin), 1);
j->cur->data->seq = ++j->seq;
j->cur->need_write = false;
j->cur->data->keys = 0;
if (fifo_full(&j->pin))
pr_debug("journal_pin full (%zu)", fifo_used(&j->pin));
}
static void journal_write_endio(struct bio *bio, int error)
{
struct journal_write *w = bio->bi_private;
cache_set_err_on(error, w->c, "journal io error");
closure_put(&w->c->journal.io.cl);
}
static void journal_write(struct closure *);
static void journal_write_done(struct closure *cl)
{
struct journal *j = container_of(cl, struct journal, io.cl);
struct cache_set *c = container_of(j, struct cache_set, journal);
struct journal_write *w = (j->cur == j->w)
? &j->w[1]
: &j->w[0];
__closure_wake_up(&w->wait);
if (c->journal_delay_ms)
closure_delay(&j->io, msecs_to_jiffies(c->journal_delay_ms));
continue_at(cl, journal_write, system_wq);
}
static void journal_write_unlocked(struct closure *cl)
__releases(c->journal.lock)
{
struct cache_set *c = container_of(cl, struct cache_set, journal.io.cl);
struct cache *ca;
struct journal_write *w = c->journal.cur;
struct bkey *k = &c->journal.key;
unsigned i, sectors = set_blocks(w->data, c) * c->sb.block_size;
struct bio *bio;
struct bio_list list;
bio_list_init(&list);
if (!w->need_write) {
/*
* XXX: have to unlock closure before we unlock journal lock,
* else we race with bch_journal(). But this way we race
* against cache set unregister. Doh.
*/
set_closure_fn(cl, NULL, NULL);
closure_sub(cl, CLOSURE_RUNNING + 1);
spin_unlock(&c->journal.lock);
return;
} else if (journal_full(&c->journal)) {
journal_reclaim(c);
spin_unlock(&c->journal.lock);
btree_flush_write(c);
continue_at(cl, journal_write, system_wq);
}
c->journal.blocks_free -= set_blocks(w->data, c);
w->data->btree_level = c->root->level;
bkey_copy(&w->data->btree_root, &c->root->key);
bkey_copy(&w->data->uuid_bucket, &c->uuid_bucket);
for_each_cache(ca, c, i)
w->data->prio_bucket[ca->sb.nr_this_dev] = ca->prio_buckets[0];
w->data->magic = jset_magic(c);
w->data->version = BCACHE_JSET_VERSION;
w->data->last_seq = last_seq(&c->journal);
w->data->csum = csum_set(w->data);
for (i = 0; i < KEY_PTRS(k); i++) {
ca = PTR_CACHE(c, k, i);
bio = &ca->journal.bio;
atomic_long_add(sectors, &ca->meta_sectors_written);
bio_reset(bio);
bio->bi_sector = PTR_OFFSET(k, i);
bio->bi_bdev = ca->bdev;
bio->bi_rw = REQ_WRITE|REQ_SYNC|REQ_META|REQ_FLUSH;
bio->bi_size = sectors << 9;
bio->bi_end_io = journal_write_endio;
bio->bi_private = w;
bch_bio_map(bio, w->data);
trace_bcache_journal_write(bio);
bio_list_add(&list, bio);
SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + sectors);
ca->journal.seq[ca->journal.cur_idx] = w->data->seq;
}
atomic_dec_bug(&fifo_back(&c->journal.pin));
bch_journal_next(&c->journal);
journal_reclaim(c);
spin_unlock(&c->journal.lock);
while ((bio = bio_list_pop(&list)))
closure_bio_submit(bio, cl, c->cache[0]);
continue_at(cl, journal_write_done, NULL);
}
static void journal_write(struct closure *cl)
{
struct cache_set *c = container_of(cl, struct cache_set, journal.io.cl);
spin_lock(&c->journal.lock);
journal_write_unlocked(cl);
}
static void __journal_try_write(struct cache_set *c, bool noflush)
__releases(c->journal.lock)
{
struct closure *cl = &c->journal.io.cl;
if (!closure_trylock(cl, &c->cl))
spin_unlock(&c->journal.lock);
else if (noflush && journal_full(&c->journal)) {
spin_unlock(&c->journal.lock);
continue_at(cl, journal_write, system_wq);
} else
journal_write_unlocked(cl);
}
#define journal_try_write(c) __journal_try_write(c, false)
void bch_journal_meta(struct cache_set *c, struct closure *cl)
{
struct journal_write *w;
if (CACHE_SYNC(&c->sb)) {
spin_lock(&c->journal.lock);
w = c->journal.cur;
w->need_write = true;
if (cl)
BUG_ON(!closure_wait(&w->wait, cl));
__journal_try_write(c, true);
}
}
/*
* Entry point to the journalling code - bio_insert() and btree_invalidate()
* pass bch_journal() a list of keys to be journalled, and then
* bch_journal() hands those same keys off to btree_insert_async()
*/
void bch_journal(struct closure *cl)
{
struct btree_op *op = container_of(cl, struct btree_op, cl);
struct cache_set *c = op->c;
struct journal_write *w;
size_t b, n = ((uint64_t *) op->keys.top) - op->keys.list;
if (op->type != BTREE_INSERT ||
!CACHE_SYNC(&c->sb))
goto out;
/*
* If we're looping because we errored, might already be waiting on
* another journal write:
*/
while (atomic_read(&cl->parent->remaining) & CLOSURE_WAITING)
closure_sync(cl->parent);
spin_lock(&c->journal.lock);
if (journal_full(&c->journal)) {
/* XXX: tracepoint */
closure_wait(&c->journal.wait, cl);
journal_reclaim(c);
spin_unlock(&c->journal.lock);
btree_flush_write(c);
continue_at(cl, bch_journal, bcache_wq);
}
w = c->journal.cur;
w->need_write = true;
b = __set_blocks(w->data, w->data->keys + n, c);
if (b * c->sb.block_size > PAGE_SECTORS << JSET_BITS ||
b > c->journal.blocks_free) {
/* XXX: If we were inserting so many keys that they won't fit in
* an _empty_ journal write, we'll deadlock. For now, handle
* this in bch_keylist_realloc() - but something to think about.
*/
BUG_ON(!w->data->keys);
/* XXX: tracepoint */
BUG_ON(!closure_wait(&w->wait, cl));
closure_flush(&c->journal.io);
journal_try_write(c);
continue_at(cl, bch_journal, bcache_wq);
}
memcpy(end(w->data), op->keys.list, n * sizeof(uint64_t));
w->data->keys += n;
op->journal = &fifo_back(&c->journal.pin);
atomic_inc(op->journal);
if (op->flush_journal) {
closure_flush(&c->journal.io);
closure_wait(&w->wait, cl->parent);
}
journal_try_write(c);
out:
bch_btree_insert_async(cl);
}
void bch_journal_free(struct cache_set *c)
{
free_pages((unsigned long) c->journal.w[1].data, JSET_BITS);
free_pages((unsigned long) c->journal.w[0].data, JSET_BITS);
free_fifo(&c->journal.pin);
}
int bch_journal_alloc(struct cache_set *c)
{
struct journal *j = &c->journal;
closure_init_unlocked(&j->io);
spin_lock_init(&j->lock);
c->journal_delay_ms = 100;
j->w[0].c = c;
j->w[1].c = c;
if (!(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL)) ||
!(j->w[0].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)) ||
!(j->w[1].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)))
return -ENOMEM;
return 0;
}