linux/fs/bcachefs/btree_write_buffer.c
Kent Overstreet 5dd8c60e1e bcachefs: iter/update/trigger/str_hash flag cleanup
Combine iter/update/trigger/str_hash flags into a single enum, and
x-macroize them for a to_text() function later.

These flags are all for a specific iter/key/update context, so it makes
sense to group them together - iter/update/trigger flags were already
given distinct bits, this cleans up and unifies that handling.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-05-08 17:29:18 -04:00

671 lines
18 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "btree_locking.h"
#include "btree_update.h"
#include "btree_update_interior.h"
#include "btree_write_buffer.h"
#include "error.h"
#include "journal.h"
#include "journal_io.h"
#include "journal_reclaim.h"
#include <linux/prefetch.h>
#include <linux/sort.h>
static int bch2_btree_write_buffer_journal_flush(struct journal *,
struct journal_entry_pin *, u64);
static int bch2_journal_keys_to_write_buffer(struct bch_fs *, struct journal_buf *);
static inline bool __wb_key_ref_cmp(const struct wb_key_ref *l, const struct wb_key_ref *r)
{
return (cmp_int(l->hi, r->hi) ?:
cmp_int(l->mi, r->mi) ?:
cmp_int(l->lo, r->lo)) >= 0;
}
static inline bool wb_key_ref_cmp(const struct wb_key_ref *l, const struct wb_key_ref *r)
{
#ifdef CONFIG_X86_64
int cmp;
asm("mov (%[l]), %%rax;"
"sub (%[r]), %%rax;"
"mov 8(%[l]), %%rax;"
"sbb 8(%[r]), %%rax;"
"mov 16(%[l]), %%rax;"
"sbb 16(%[r]), %%rax;"
: "=@ccae" (cmp)
: [l] "r" (l), [r] "r" (r)
: "rax", "cc");
EBUG_ON(cmp != __wb_key_ref_cmp(l, r));
return cmp;
#else
return __wb_key_ref_cmp(l, r);
#endif
}
static int wb_key_seq_cmp(const void *_l, const void *_r)
{
const struct btree_write_buffered_key *l = _l;
const struct btree_write_buffered_key *r = _r;
return cmp_int(l->journal_seq, r->journal_seq);
}
/* Compare excluding idx, the low 24 bits: */
static inline bool wb_key_eq(const void *_l, const void *_r)
{
const struct wb_key_ref *l = _l;
const struct wb_key_ref *r = _r;
return !((l->hi ^ r->hi)|
(l->mi ^ r->mi)|
((l->lo >> 24) ^ (r->lo >> 24)));
}
static noinline void wb_sort(struct wb_key_ref *base, size_t num)
{
size_t n = num, a = num / 2;
if (!a) /* num < 2 || size == 0 */
return;
for (;;) {
size_t b, c, d;
if (a) /* Building heap: sift down --a */
--a;
else if (--n) /* Sorting: Extract root to --n */
swap(base[0], base[n]);
else /* Sort complete */
break;
/*
* Sift element at "a" down into heap. This is the
* "bottom-up" variant, which significantly reduces
* calls to cmp_func(): we find the sift-down path all
* the way to the leaves (one compare per level), then
* backtrack to find where to insert the target element.
*
* Because elements tend to sift down close to the leaves,
* this uses fewer compares than doing two per level
* on the way down. (A bit more than half as many on
* average, 3/4 worst-case.)
*/
for (b = a; c = 2*b + 1, (d = c + 1) < n;)
b = wb_key_ref_cmp(base + c, base + d) ? c : d;
if (d == n) /* Special case last leaf with no sibling */
b = c;
/* Now backtrack from "b" to the correct location for "a" */
while (b != a && wb_key_ref_cmp(base + a, base + b))
b = (b - 1) / 2;
c = b; /* Where "a" belongs */
while (b != a) { /* Shift it into place */
b = (b - 1) / 2;
swap(base[b], base[c]);
}
}
}
static noinline int wb_flush_one_slowpath(struct btree_trans *trans,
struct btree_iter *iter,
struct btree_write_buffered_key *wb)
{
struct btree_path *path = btree_iter_path(trans, iter);
bch2_btree_node_unlock_write(trans, path, path->l[0].b);
trans->journal_res.seq = wb->journal_seq;
return bch2_trans_update(trans, iter, &wb->k,
BTREE_UPDATE_internal_snapshot_node) ?:
bch2_trans_commit(trans, NULL, NULL,
BCH_TRANS_COMMIT_no_enospc|
BCH_TRANS_COMMIT_no_check_rw|
BCH_TRANS_COMMIT_no_journal_res|
BCH_TRANS_COMMIT_journal_reclaim);
}
static inline int wb_flush_one(struct btree_trans *trans, struct btree_iter *iter,
struct btree_write_buffered_key *wb,
bool *write_locked, size_t *fast)
{
struct btree_path *path;
int ret;
EBUG_ON(!wb->journal_seq);
EBUG_ON(!trans->c->btree_write_buffer.flushing.pin.seq);
EBUG_ON(trans->c->btree_write_buffer.flushing.pin.seq > wb->journal_seq);
ret = bch2_btree_iter_traverse(iter);
if (ret)
return ret;
/*
* We can't clone a path that has write locks: unshare it now, before
* set_pos and traverse():
*/
if (btree_iter_path(trans, iter)->ref > 1)
iter->path = __bch2_btree_path_make_mut(trans, iter->path, true, _THIS_IP_);
path = btree_iter_path(trans, iter);
if (!*write_locked) {
ret = bch2_btree_node_lock_write(trans, path, &path->l[0].b->c);
if (ret)
return ret;
bch2_btree_node_prep_for_write(trans, path, path->l[0].b);
*write_locked = true;
}
if (unlikely(!bch2_btree_node_insert_fits(path->l[0].b, wb->k.k.u64s))) {
*write_locked = false;
return wb_flush_one_slowpath(trans, iter, wb);
}
bch2_btree_insert_key_leaf(trans, path, &wb->k, wb->journal_seq);
(*fast)++;
return 0;
}
/*
* Update a btree with a write buffered key using the journal seq of the
* original write buffer insert.
*
* It is not safe to rejournal the key once it has been inserted into the write
* buffer because that may break recovery ordering. For example, the key may
* have already been modified in the active write buffer in a seq that comes
* before the current transaction. If we were to journal this key again and
* crash, recovery would process updates in the wrong order.
*/
static int
btree_write_buffered_insert(struct btree_trans *trans,
struct btree_write_buffered_key *wb)
{
struct btree_iter iter;
int ret;
bch2_trans_iter_init(trans, &iter, wb->btree, bkey_start_pos(&wb->k.k),
BTREE_ITER_cached|BTREE_ITER_intent);
trans->journal_res.seq = wb->journal_seq;
ret = bch2_btree_iter_traverse(&iter) ?:
bch2_trans_update(trans, &iter, &wb->k,
BTREE_UPDATE_internal_snapshot_node);
bch2_trans_iter_exit(trans, &iter);
return ret;
}
static void move_keys_from_inc_to_flushing(struct btree_write_buffer *wb)
{
struct bch_fs *c = container_of(wb, struct bch_fs, btree_write_buffer);
struct journal *j = &c->journal;
if (!wb->inc.keys.nr)
return;
bch2_journal_pin_add(j, wb->inc.keys.data[0].journal_seq, &wb->flushing.pin,
bch2_btree_write_buffer_journal_flush);
darray_resize(&wb->flushing.keys, min_t(size_t, 1U << 20, wb->flushing.keys.nr + wb->inc.keys.nr));
darray_resize(&wb->sorted, wb->flushing.keys.size);
if (!wb->flushing.keys.nr && wb->sorted.size >= wb->inc.keys.nr) {
swap(wb->flushing.keys, wb->inc.keys);
goto out;
}
size_t nr = min(darray_room(wb->flushing.keys),
wb->sorted.size - wb->flushing.keys.nr);
nr = min(nr, wb->inc.keys.nr);
memcpy(&darray_top(wb->flushing.keys),
wb->inc.keys.data,
sizeof(wb->inc.keys.data[0]) * nr);
memmove(wb->inc.keys.data,
wb->inc.keys.data + nr,
sizeof(wb->inc.keys.data[0]) * (wb->inc.keys.nr - nr));
wb->flushing.keys.nr += nr;
wb->inc.keys.nr -= nr;
out:
if (!wb->inc.keys.nr)
bch2_journal_pin_drop(j, &wb->inc.pin);
else
bch2_journal_pin_update(j, wb->inc.keys.data[0].journal_seq, &wb->inc.pin,
bch2_btree_write_buffer_journal_flush);
if (j->watermark) {
spin_lock(&j->lock);
bch2_journal_set_watermark(j);
spin_unlock(&j->lock);
}
BUG_ON(wb->sorted.size < wb->flushing.keys.nr);
}
static int bch2_btree_write_buffer_flush_locked(struct btree_trans *trans)
{
struct bch_fs *c = trans->c;
struct journal *j = &c->journal;
struct btree_write_buffer *wb = &c->btree_write_buffer;
struct btree_iter iter = { NULL };
size_t skipped = 0, fast = 0, slowpath = 0;
bool write_locked = false;
int ret = 0;
bch2_trans_unlock(trans);
bch2_trans_begin(trans);
mutex_lock(&wb->inc.lock);
move_keys_from_inc_to_flushing(wb);
mutex_unlock(&wb->inc.lock);
for (size_t i = 0; i < wb->flushing.keys.nr; i++) {
wb->sorted.data[i].idx = i;
wb->sorted.data[i].btree = wb->flushing.keys.data[i].btree;
memcpy(&wb->sorted.data[i].pos, &wb->flushing.keys.data[i].k.k.p, sizeof(struct bpos));
}
wb->sorted.nr = wb->flushing.keys.nr;
/*
* We first sort so that we can detect and skip redundant updates, and
* then we attempt to flush in sorted btree order, as this is most
* efficient.
*
* However, since we're not flushing in the order they appear in the
* journal we won't be able to drop our journal pin until everything is
* flushed - which means this could deadlock the journal if we weren't
* passing BCH_TRANS_COMMIT_journal_reclaim. This causes the update to fail
* if it would block taking a journal reservation.
*
* If that happens, simply skip the key so we can optimistically insert
* as many keys as possible in the fast path.
*/
wb_sort(wb->sorted.data, wb->sorted.nr);
darray_for_each(wb->sorted, i) {
struct btree_write_buffered_key *k = &wb->flushing.keys.data[i->idx];
for (struct wb_key_ref *n = i + 1; n < min(i + 4, &darray_top(wb->sorted)); n++)
prefetch(&wb->flushing.keys.data[n->idx]);
BUG_ON(!k->journal_seq);
if (i + 1 < &darray_top(wb->sorted) &&
wb_key_eq(i, i + 1)) {
struct btree_write_buffered_key *n = &wb->flushing.keys.data[i[1].idx];
skipped++;
n->journal_seq = min_t(u64, n->journal_seq, k->journal_seq);
k->journal_seq = 0;
continue;
}
if (write_locked) {
struct btree_path *path = btree_iter_path(trans, &iter);
if (path->btree_id != i->btree ||
bpos_gt(k->k.k.p, path->l[0].b->key.k.p)) {
bch2_btree_node_unlock_write(trans, path, path->l[0].b);
write_locked = false;
ret = lockrestart_do(trans,
bch2_btree_iter_traverse(&iter) ?:
bch2_foreground_maybe_merge(trans, iter.path, 0,
BCH_WATERMARK_reclaim|
BCH_TRANS_COMMIT_journal_reclaim|
BCH_TRANS_COMMIT_no_check_rw|
BCH_TRANS_COMMIT_no_enospc));
if (ret)
goto err;
}
}
if (!iter.path || iter.btree_id != k->btree) {
bch2_trans_iter_exit(trans, &iter);
bch2_trans_iter_init(trans, &iter, k->btree, k->k.k.p,
BTREE_ITER_intent|BTREE_ITER_all_snapshots);
}
bch2_btree_iter_set_pos(&iter, k->k.k.p);
btree_iter_path(trans, &iter)->preserve = false;
do {
if (race_fault()) {
ret = -BCH_ERR_journal_reclaim_would_deadlock;
break;
}
ret = wb_flush_one(trans, &iter, k, &write_locked, &fast);
if (!write_locked)
bch2_trans_begin(trans);
} while (bch2_err_matches(ret, BCH_ERR_transaction_restart));
if (!ret) {
k->journal_seq = 0;
} else if (ret == -BCH_ERR_journal_reclaim_would_deadlock) {
slowpath++;
ret = 0;
} else
break;
}
if (write_locked) {
struct btree_path *path = btree_iter_path(trans, &iter);
bch2_btree_node_unlock_write(trans, path, path->l[0].b);
}
bch2_trans_iter_exit(trans, &iter);
if (ret)
goto err;
if (slowpath) {
/*
* Flush in the order they were present in the journal, so that
* we can release journal pins:
* The fastpath zapped the seq of keys that were successfully flushed so
* we can skip those here.
*/
trace_and_count(c, write_buffer_flush_slowpath, trans, slowpath, wb->flushing.keys.nr);
sort(wb->flushing.keys.data,
wb->flushing.keys.nr,
sizeof(wb->flushing.keys.data[0]),
wb_key_seq_cmp, NULL);
darray_for_each(wb->flushing.keys, i) {
if (!i->journal_seq)
continue;
bch2_journal_pin_update(j, i->journal_seq, &wb->flushing.pin,
bch2_btree_write_buffer_journal_flush);
bch2_trans_begin(trans);
ret = commit_do(trans, NULL, NULL,
BCH_WATERMARK_reclaim|
BCH_TRANS_COMMIT_journal_reclaim|
BCH_TRANS_COMMIT_no_check_rw|
BCH_TRANS_COMMIT_no_enospc|
BCH_TRANS_COMMIT_no_journal_res ,
btree_write_buffered_insert(trans, i));
if (ret)
goto err;
}
}
err:
bch2_fs_fatal_err_on(ret, c, "%s", bch2_err_str(ret));
trace_write_buffer_flush(trans, wb->flushing.keys.nr, skipped, fast, 0);
bch2_journal_pin_drop(j, &wb->flushing.pin);
wb->flushing.keys.nr = 0;
return ret;
}
static int fetch_wb_keys_from_journal(struct bch_fs *c, u64 seq)
{
struct journal *j = &c->journal;
struct journal_buf *buf;
int ret = 0;
while (!ret && (buf = bch2_next_write_buffer_flush_journal_buf(j, seq))) {
ret = bch2_journal_keys_to_write_buffer(c, buf);
mutex_unlock(&j->buf_lock);
}
return ret;
}
static int btree_write_buffer_flush_seq(struct btree_trans *trans, u64 seq)
{
struct bch_fs *c = trans->c;
struct btree_write_buffer *wb = &c->btree_write_buffer;
int ret = 0, fetch_from_journal_err;
do {
bch2_trans_unlock(trans);
fetch_from_journal_err = fetch_wb_keys_from_journal(c, seq);
/*
* On memory allocation failure, bch2_btree_write_buffer_flush_locked()
* is not guaranteed to empty wb->inc:
*/
mutex_lock(&wb->flushing.lock);
ret = bch2_btree_write_buffer_flush_locked(trans);
mutex_unlock(&wb->flushing.lock);
} while (!ret &&
(fetch_from_journal_err ||
(wb->inc.pin.seq && wb->inc.pin.seq <= seq) ||
(wb->flushing.pin.seq && wb->flushing.pin.seq <= seq)));
return ret;
}
static int bch2_btree_write_buffer_journal_flush(struct journal *j,
struct journal_entry_pin *_pin, u64 seq)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
return bch2_trans_run(c, btree_write_buffer_flush_seq(trans, seq));
}
int bch2_btree_write_buffer_flush_sync(struct btree_trans *trans)
{
struct bch_fs *c = trans->c;
trace_and_count(c, write_buffer_flush_sync, trans, _RET_IP_);
return btree_write_buffer_flush_seq(trans, journal_cur_seq(&c->journal));
}
int bch2_btree_write_buffer_flush_nocheck_rw(struct btree_trans *trans)
{
struct bch_fs *c = trans->c;
struct btree_write_buffer *wb = &c->btree_write_buffer;
int ret = 0;
if (mutex_trylock(&wb->flushing.lock)) {
ret = bch2_btree_write_buffer_flush_locked(trans);
mutex_unlock(&wb->flushing.lock);
}
return ret;
}
int bch2_btree_write_buffer_tryflush(struct btree_trans *trans)
{
struct bch_fs *c = trans->c;
if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_btree_write_buffer))
return -BCH_ERR_erofs_no_writes;
int ret = bch2_btree_write_buffer_flush_nocheck_rw(trans);
bch2_write_ref_put(c, BCH_WRITE_REF_btree_write_buffer);
return ret;
}
static void bch2_btree_write_buffer_flush_work(struct work_struct *work)
{
struct bch_fs *c = container_of(work, struct bch_fs, btree_write_buffer.flush_work);
struct btree_write_buffer *wb = &c->btree_write_buffer;
int ret;
mutex_lock(&wb->flushing.lock);
do {
ret = bch2_trans_run(c, bch2_btree_write_buffer_flush_locked(trans));
} while (!ret && bch2_btree_write_buffer_should_flush(c));
mutex_unlock(&wb->flushing.lock);
bch2_write_ref_put(c, BCH_WRITE_REF_btree_write_buffer);
}
int bch2_journal_key_to_wb_slowpath(struct bch_fs *c,
struct journal_keys_to_wb *dst,
enum btree_id btree, struct bkey_i *k)
{
struct btree_write_buffer *wb = &c->btree_write_buffer;
int ret;
retry:
ret = darray_make_room_gfp(&dst->wb->keys, 1, GFP_KERNEL);
if (!ret && dst->wb == &wb->flushing)
ret = darray_resize(&wb->sorted, wb->flushing.keys.size);
if (unlikely(ret)) {
if (dst->wb == &c->btree_write_buffer.flushing) {
mutex_unlock(&dst->wb->lock);
dst->wb = &c->btree_write_buffer.inc;
bch2_journal_pin_add(&c->journal, dst->seq, &dst->wb->pin,
bch2_btree_write_buffer_journal_flush);
goto retry;
}
return ret;
}
dst->room = darray_room(dst->wb->keys);
if (dst->wb == &wb->flushing)
dst->room = min(dst->room, wb->sorted.size - wb->flushing.keys.nr);
BUG_ON(!dst->room);
BUG_ON(!dst->seq);
struct btree_write_buffered_key *wb_k = &darray_top(dst->wb->keys);
wb_k->journal_seq = dst->seq;
wb_k->btree = btree;
bkey_copy(&wb_k->k, k);
dst->wb->keys.nr++;
dst->room--;
return 0;
}
void bch2_journal_keys_to_write_buffer_start(struct bch_fs *c, struct journal_keys_to_wb *dst, u64 seq)
{
struct btree_write_buffer *wb = &c->btree_write_buffer;
if (mutex_trylock(&wb->flushing.lock)) {
mutex_lock(&wb->inc.lock);
move_keys_from_inc_to_flushing(wb);
/*
* Attempt to skip wb->inc, and add keys directly to
* wb->flushing, saving us a copy later:
*/
if (!wb->inc.keys.nr) {
dst->wb = &wb->flushing;
} else {
mutex_unlock(&wb->flushing.lock);
dst->wb = &wb->inc;
}
} else {
mutex_lock(&wb->inc.lock);
dst->wb = &wb->inc;
}
dst->room = darray_room(dst->wb->keys);
if (dst->wb == &wb->flushing)
dst->room = min(dst->room, wb->sorted.size - wb->flushing.keys.nr);
dst->seq = seq;
bch2_journal_pin_add(&c->journal, seq, &dst->wb->pin,
bch2_btree_write_buffer_journal_flush);
}
void bch2_journal_keys_to_write_buffer_end(struct bch_fs *c, struct journal_keys_to_wb *dst)
{
struct btree_write_buffer *wb = &c->btree_write_buffer;
if (!dst->wb->keys.nr)
bch2_journal_pin_drop(&c->journal, &dst->wb->pin);
if (bch2_btree_write_buffer_should_flush(c) &&
__bch2_write_ref_tryget(c, BCH_WRITE_REF_btree_write_buffer) &&
!queue_work(system_unbound_wq, &c->btree_write_buffer.flush_work))
bch2_write_ref_put(c, BCH_WRITE_REF_btree_write_buffer);
if (dst->wb == &wb->flushing)
mutex_unlock(&wb->flushing.lock);
mutex_unlock(&wb->inc.lock);
}
static int bch2_journal_keys_to_write_buffer(struct bch_fs *c, struct journal_buf *buf)
{
struct journal_keys_to_wb dst;
int ret = 0;
bch2_journal_keys_to_write_buffer_start(c, &dst, le64_to_cpu(buf->data->seq));
for_each_jset_entry_type(entry, buf->data, BCH_JSET_ENTRY_write_buffer_keys) {
jset_entry_for_each_key(entry, k) {
ret = bch2_journal_key_to_wb(c, &dst, entry->btree_id, k);
if (ret)
goto out;
}
entry->type = BCH_JSET_ENTRY_btree_keys;
}
spin_lock(&c->journal.lock);
buf->need_flush_to_write_buffer = false;
spin_unlock(&c->journal.lock);
out:
bch2_journal_keys_to_write_buffer_end(c, &dst);
return ret;
}
static int wb_keys_resize(struct btree_write_buffer_keys *wb, size_t new_size)
{
if (wb->keys.size >= new_size)
return 0;
if (!mutex_trylock(&wb->lock))
return -EINTR;
int ret = darray_resize(&wb->keys, new_size);
mutex_unlock(&wb->lock);
return ret;
}
int bch2_btree_write_buffer_resize(struct bch_fs *c, size_t new_size)
{
struct btree_write_buffer *wb = &c->btree_write_buffer;
return wb_keys_resize(&wb->flushing, new_size) ?:
wb_keys_resize(&wb->inc, new_size);
}
void bch2_fs_btree_write_buffer_exit(struct bch_fs *c)
{
struct btree_write_buffer *wb = &c->btree_write_buffer;
BUG_ON((wb->inc.keys.nr || wb->flushing.keys.nr) &&
!bch2_journal_error(&c->journal));
darray_exit(&wb->sorted);
darray_exit(&wb->flushing.keys);
darray_exit(&wb->inc.keys);
}
int bch2_fs_btree_write_buffer_init(struct bch_fs *c)
{
struct btree_write_buffer *wb = &c->btree_write_buffer;
mutex_init(&wb->inc.lock);
mutex_init(&wb->flushing.lock);
INIT_WORK(&wb->flush_work, bch2_btree_write_buffer_flush_work);
/* Will be resized by journal as needed: */
unsigned initial_size = 1 << 16;
return darray_make_room(&wb->inc.keys, initial_size) ?:
darray_make_room(&wb->flushing.keys, initial_size) ?:
darray_make_room(&wb->sorted, initial_size);
}