--- /dev/null
+// 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>
+
+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
+}
+
+/* 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 bch_fs *c = trans->c;
+ struct btree_path *path;
+ int ret;
+
+ EBUG_ON(!wb->journal_seq);
+ EBUG_ON(!c->btree_write_buffer.flushing.pin.seq);
+ EBUG_ON(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(c, 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;
+ }
+ }
+
+ 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);
+
+ 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_no_check_rw|
+ BCH_TRANS_COMMIT_no_enospc|
+ BCH_TRANS_COMMIT_no_journal_res|
+ BCH_TRANS_COMMIT_journal_reclaim,
+ btree_write_buffered_insert(trans, i));
+ if (ret)
+ goto err;
+ }
+ }
+err:
+ bch2_fs_fatal_err_on(ret, c, "%s: insert error %s", __func__, 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;
+ struct jset_entry *entry;
+ struct bkey_i *k;
+ 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;
+ }
+
+ buf->need_flush_to_write_buffer = false;
+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);
+}
projects / bcachefs-tools-debian / blobdiff