Merge tag 'kvm-x86-generic-6.8' of https://github.com/kvm-x86/linux into HEAD

[thirdparty/kernel/stable.git] / fs / bcachefs / btree_trans_commit.c

// SPDX-License-Identifier: GPL-2.0

#include "bcachefs.h"
#include "btree_gc.h"
#include "btree_io.h"
#include "btree_iter.h"
#include "btree_journal_iter.h"
#include "btree_key_cache.h"
#include "btree_update_interior.h"
#include "btree_write_buffer.h"
#include "buckets.h"
#include "errcode.h"
#include "error.h"
#include "journal.h"
#include "journal_reclaim.h"
#include "replicas.h"
#include "snapshot.h"

#include <linux/prefetch.h>

static void verify_update_old_key(struct btree_trans *trans, struct btree_insert_entry *i)
{
#ifdef CONFIG_BCACHEFS_DEBUG
        struct bch_fs *c = trans->c;
        struct bkey u;
        struct bkey_s_c k = bch2_btree_path_peek_slot_exact(i->path, &u);

        if (unlikely(trans->journal_replay_not_finished)) {
                struct bkey_i *j_k =
                        bch2_journal_keys_peek_slot(c, i->btree_id, i->level, i->k->k.p);

                if (j_k)
                        k = bkey_i_to_s_c(j_k);
        }

        u = *k.k;
        u.needs_whiteout = i->old_k.needs_whiteout;

        BUG_ON(memcmp(&i->old_k, &u, sizeof(struct bkey)));
        BUG_ON(i->old_v != k.v);
#endif
}

static inline struct btree_path_level *insert_l(struct btree_insert_entry *i)
{
        return i->path->l + i->level;
}

static inline bool same_leaf_as_prev(struct btree_trans *trans,
                                     struct btree_insert_entry *i)
{
        return i != trans->updates &&
                insert_l(&i[0])->b == insert_l(&i[-1])->b;
}

static inline bool same_leaf_as_next(struct btree_trans *trans,
                                     struct btree_insert_entry *i)
{
        return i + 1 < trans->updates + trans->nr_updates &&
                insert_l(&i[0])->b == insert_l(&i[1])->b;
}

inline void bch2_btree_node_prep_for_write(struct btree_trans *trans,
                                           struct btree_path *path,
                                           struct btree *b)
{
        struct bch_fs *c = trans->c;

        if (unlikely(btree_node_just_written(b)) &&
            bch2_btree_post_write_cleanup(c, b))
                bch2_trans_node_reinit_iter(trans, b);

        /*
         * If the last bset has been written, or if it's gotten too big - start
         * a new bset to insert into:
         */
        if (want_new_bset(c, b))
                bch2_btree_init_next(trans, b);
}

static noinline int trans_lock_write_fail(struct btree_trans *trans, struct btree_insert_entry *i)
{
        while (--i >= trans->updates) {
                if (same_leaf_as_prev(trans, i))
                        continue;

                bch2_btree_node_unlock_write(trans, i->path, insert_l(i)->b);
        }

        trace_and_count(trans->c, trans_restart_would_deadlock_write, trans);
        return btree_trans_restart(trans, BCH_ERR_transaction_restart_would_deadlock_write);
}

static inline int bch2_trans_lock_write(struct btree_trans *trans)
{
        struct btree_insert_entry *i;

        EBUG_ON(trans->write_locked);

        trans_for_each_update(trans, i) {
                if (same_leaf_as_prev(trans, i))
                        continue;

                if (bch2_btree_node_lock_write(trans, i->path, &insert_l(i)->b->c))
                        return trans_lock_write_fail(trans, i);

                if (!i->cached)
                        bch2_btree_node_prep_for_write(trans, i->path, insert_l(i)->b);
        }

        trans->write_locked = true;
        return 0;
}

static inline void bch2_trans_unlock_write(struct btree_trans *trans)
{
        if (likely(trans->write_locked)) {
                struct btree_insert_entry *i;

                trans_for_each_update(trans, i)
                        if (!same_leaf_as_prev(trans, i))
                                bch2_btree_node_unlock_write_inlined(trans, i->path,
                                                                     insert_l(i)->b);
                trans->write_locked = false;
        }
}

/* Inserting into a given leaf node (last stage of insert): */

/* Handle overwrites and do insert, for non extents: */
bool bch2_btree_bset_insert_key(struct btree_trans *trans,
                                struct btree_path *path,
                                struct btree *b,
                                struct btree_node_iter *node_iter,
                                struct bkey_i *insert)
{
        struct bkey_packed *k;
        unsigned clobber_u64s = 0, new_u64s = 0;

        EBUG_ON(btree_node_just_written(b));
        EBUG_ON(bset_written(b, btree_bset_last(b)));
        EBUG_ON(bkey_deleted(&insert->k) && bkey_val_u64s(&insert->k));
        EBUG_ON(bpos_lt(insert->k.p, b->data->min_key));
        EBUG_ON(bpos_gt(insert->k.p, b->data->max_key));
        EBUG_ON(insert->k.u64s >
                bch_btree_keys_u64s_remaining(trans->c, b));
        EBUG_ON(!b->c.level && !bpos_eq(insert->k.p, path->pos));

        k = bch2_btree_node_iter_peek_all(node_iter, b);
        if (k && bkey_cmp_left_packed(b, k, &insert->k.p))
                k = NULL;

        /* @k is the key being overwritten/deleted, if any: */
        EBUG_ON(k && bkey_deleted(k));

        /* Deleting, but not found? nothing to do: */
        if (bkey_deleted(&insert->k) && !k)
                return false;

        if (bkey_deleted(&insert->k)) {
                /* Deleting: */
                btree_account_key_drop(b, k);
                k->type = KEY_TYPE_deleted;

                if (k->needs_whiteout)
                        push_whiteout(trans->c, b, insert->k.p);
                k->needs_whiteout = false;

                if (k >= btree_bset_last(b)->start) {
                        clobber_u64s = k->u64s;
                        bch2_bset_delete(b, k, clobber_u64s);
                        goto fix_iter;
                } else {
                        bch2_btree_path_fix_key_modified(trans, b, k);
                }

                return true;
        }

        if (k) {
                /* Overwriting: */
                btree_account_key_drop(b, k);
                k->type = KEY_TYPE_deleted;

                insert->k.needs_whiteout = k->needs_whiteout;
                k->needs_whiteout = false;

                if (k >= btree_bset_last(b)->start) {
                        clobber_u64s = k->u64s;
                        goto overwrite;
                } else {
                        bch2_btree_path_fix_key_modified(trans, b, k);
                }
        }

        k = bch2_btree_node_iter_bset_pos(node_iter, b, bset_tree_last(b));
overwrite:
        bch2_bset_insert(b, node_iter, k, insert, clobber_u64s);
        new_u64s = k->u64s;
fix_iter:
        if (clobber_u64s != new_u64s)
                bch2_btree_node_iter_fix(trans, path, b, node_iter, k,
                                         clobber_u64s, new_u64s);
        return true;
}

static int __btree_node_flush(struct journal *j, struct journal_entry_pin *pin,
                               unsigned i, u64 seq)
{
        struct bch_fs *c = container_of(j, struct bch_fs, journal);
        struct btree_write *w = container_of(pin, struct btree_write, journal);
        struct btree *b = container_of(w, struct btree, writes[i]);
        struct btree_trans *trans = bch2_trans_get(c);
        unsigned long old, new, v;
        unsigned idx = w - b->writes;

        btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_read);
        v = READ_ONCE(b->flags);

        do {
                old = new = v;

                if (!(old & (1 << BTREE_NODE_dirty)) ||
                    !!(old & (1 << BTREE_NODE_write_idx)) != idx ||
                    w->journal.seq != seq)
                        break;

                new &= ~BTREE_WRITE_TYPE_MASK;
                new |= BTREE_WRITE_journal_reclaim;
                new |= 1 << BTREE_NODE_need_write;
        } while ((v = cmpxchg(&b->flags, old, new)) != old);

        btree_node_write_if_need(c, b, SIX_LOCK_read);
        six_unlock_read(&b->c.lock);

        bch2_trans_put(trans);
        return 0;
}

int bch2_btree_node_flush0(struct journal *j, struct journal_entry_pin *pin, u64 seq)
{
        return __btree_node_flush(j, pin, 0, seq);
}

int bch2_btree_node_flush1(struct journal *j, struct journal_entry_pin *pin, u64 seq)
{
        return __btree_node_flush(j, pin, 1, seq);
}

inline void bch2_btree_add_journal_pin(struct bch_fs *c,
                                       struct btree *b, u64 seq)
{
        struct btree_write *w = btree_current_write(b);

        bch2_journal_pin_add(&c->journal, seq, &w->journal,
                             btree_node_write_idx(b) == 0
                             ? bch2_btree_node_flush0
                             : bch2_btree_node_flush1);
}

/**
 * bch2_btree_insert_key_leaf() - insert a key one key into a leaf node
 * @trans:              btree transaction object
 * @path:               path pointing to @insert's pos
 * @insert:             key to insert
 * @journal_seq:        sequence number of journal reservation
 */
inline void bch2_btree_insert_key_leaf(struct btree_trans *trans,
                                       struct btree_path *path,
                                       struct bkey_i *insert,
                                       u64 journal_seq)
{
        struct bch_fs *c = trans->c;
        struct btree *b = path_l(path)->b;
        struct bset_tree *t = bset_tree_last(b);
        struct bset *i = bset(b, t);
        int old_u64s = bset_u64s(t);
        int old_live_u64s = b->nr.live_u64s;
        int live_u64s_added, u64s_added;

        if (unlikely(!bch2_btree_bset_insert_key(trans, path, b,
                                        &path_l(path)->iter, insert)))
                return;

        i->journal_seq = cpu_to_le64(max(journal_seq, le64_to_cpu(i->journal_seq)));

        bch2_btree_add_journal_pin(c, b, journal_seq);

        if (unlikely(!btree_node_dirty(b))) {
                EBUG_ON(test_bit(BCH_FS_CLEAN_SHUTDOWN, &c->flags));
                set_btree_node_dirty_acct(c, b);
        }

        live_u64s_added = (int) b->nr.live_u64s - old_live_u64s;
        u64s_added = (int) bset_u64s(t) - old_u64s;

        if (b->sib_u64s[0] != U16_MAX && live_u64s_added < 0)
                b->sib_u64s[0] = max(0, (int) b->sib_u64s[0] + live_u64s_added);
        if (b->sib_u64s[1] != U16_MAX && live_u64s_added < 0)
                b->sib_u64s[1] = max(0, (int) b->sib_u64s[1] + live_u64s_added);

        if (u64s_added > live_u64s_added &&
            bch2_maybe_compact_whiteouts(c, b))
                bch2_trans_node_reinit_iter(trans, b);
}

/* Cached btree updates: */

/* Normal update interface: */

static inline void btree_insert_entry_checks(struct btree_trans *trans,
                                             struct btree_insert_entry *i)
{
        BUG_ON(!bpos_eq(i->k->k.p, i->path->pos));
        BUG_ON(i->cached        != i->path->cached);
        BUG_ON(i->level         != i->path->level);
        BUG_ON(i->btree_id      != i->path->btree_id);
        EBUG_ON(!i->level &&
                btree_type_has_snapshots(i->btree_id) &&
                !(i->flags & BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) &&
                test_bit(JOURNAL_REPLAY_DONE, &trans->c->journal.flags) &&
                i->k->k.p.snapshot &&
                bch2_snapshot_is_internal_node(trans->c, i->k->k.p.snapshot));
}

static __always_inline int bch2_trans_journal_res_get(struct btree_trans *trans,
                                                      unsigned flags)
{
        return bch2_journal_res_get(&trans->c->journal, &trans->journal_res,
                                    trans->journal_u64s, flags);
}

#define JSET_ENTRY_LOG_U64s             4

static noinline void journal_transaction_name(struct btree_trans *trans)
{
        struct bch_fs *c = trans->c;
        struct journal *j = &c->journal;
        struct jset_entry *entry =
                bch2_journal_add_entry(j, &trans->journal_res,
                                       BCH_JSET_ENTRY_log, 0, 0,
                                       JSET_ENTRY_LOG_U64s);
        struct jset_entry_log *l =
                container_of(entry, struct jset_entry_log, entry);

        strncpy(l->d, trans->fn, JSET_ENTRY_LOG_U64s * sizeof(u64));
}

static inline int btree_key_can_insert(struct btree_trans *trans,
                                       struct btree *b, unsigned u64s)
{
        struct bch_fs *c = trans->c;

        if (!bch2_btree_node_insert_fits(c, b, u64s))
                return -BCH_ERR_btree_insert_btree_node_full;

        return 0;
}

noinline static int
btree_key_can_insert_cached_slowpath(struct btree_trans *trans, unsigned flags,
                                     struct btree_path *path, unsigned new_u64s)
{
        struct bch_fs *c = trans->c;
        struct btree_insert_entry *i;
        struct bkey_cached *ck = (void *) path->l[0].b;
        struct bkey_i *new_k;
        int ret;

        bch2_trans_unlock_write(trans);
        bch2_trans_unlock(trans);

        new_k = kmalloc(new_u64s * sizeof(u64), GFP_KERNEL);
        if (!new_k) {
                bch_err(c, "error allocating memory for key cache key, btree %s u64s %u",
                        bch2_btree_id_str(path->btree_id), new_u64s);
                return -BCH_ERR_ENOMEM_btree_key_cache_insert;
        }

        ret =   bch2_trans_relock(trans) ?:
                bch2_trans_lock_write(trans);
        if (unlikely(ret)) {
                kfree(new_k);
                return ret;
        }

        memcpy(new_k, ck->k, ck->u64s * sizeof(u64));

        trans_for_each_update(trans, i)
                if (i->old_v == &ck->k->v)
                        i->old_v = &new_k->v;

        kfree(ck->k);
        ck->u64s        = new_u64s;
        ck->k           = new_k;
        return 0;
}

static int btree_key_can_insert_cached(struct btree_trans *trans, unsigned flags,
                                       struct btree_path *path, unsigned u64s)
{
        struct bch_fs *c = trans->c;
        struct bkey_cached *ck = (void *) path->l[0].b;
        struct btree_insert_entry *i;
        unsigned new_u64s;
        struct bkey_i *new_k;

        EBUG_ON(path->level);

        if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags) &&
            bch2_btree_key_cache_must_wait(c) &&
            !(flags & BTREE_INSERT_JOURNAL_RECLAIM))
                return -BCH_ERR_btree_insert_need_journal_reclaim;

        /*
         * bch2_varint_decode can read past the end of the buffer by at most 7
         * bytes (it won't be used):
         */
        u64s += 1;

        if (u64s <= ck->u64s)
                return 0;

        new_u64s        = roundup_pow_of_two(u64s);
        new_k           = krealloc(ck->k, new_u64s * sizeof(u64), GFP_NOWAIT);
        if (unlikely(!new_k))
                return btree_key_can_insert_cached_slowpath(trans, flags, path, new_u64s);

        trans_for_each_update(trans, i)
                if (i->old_v == &ck->k->v)
                        i->old_v = &new_k->v;

        ck->u64s        = new_u64s;
        ck->k           = new_k;
        return 0;
}

/* Triggers: */

static int run_one_mem_trigger(struct btree_trans *trans,
                               struct btree_insert_entry *i,
                               unsigned flags)
{
        struct bkey_s_c old = { &i->old_k, i->old_v };
        struct bkey_i *new = i->k;
        const struct bkey_ops *old_ops = bch2_bkey_type_ops(old.k->type);
        const struct bkey_ops *new_ops = bch2_bkey_type_ops(i->k->k.type);
        int ret;

        verify_update_old_key(trans, i);

        if (unlikely(flags & BTREE_TRIGGER_NORUN))
                return 0;

        if (!btree_node_type_needs_gc(__btree_node_type(i->level, i->btree_id)))
                return 0;

        if (old_ops->atomic_trigger == new_ops->atomic_trigger) {
                ret   = bch2_mark_key(trans, i->btree_id, i->level,
                                old, bkey_i_to_s_c(new),
                                BTREE_TRIGGER_INSERT|BTREE_TRIGGER_OVERWRITE|flags);
        } else {
                struct bkey             _deleted = KEY(0, 0, 0);
                struct bkey_s_c         deleted = (struct bkey_s_c) { &_deleted, NULL };

                _deleted.p = i->path->pos;

                ret   = bch2_mark_key(trans, i->btree_id, i->level,
                                deleted, bkey_i_to_s_c(new),
                                BTREE_TRIGGER_INSERT|flags) ?:
                        bch2_mark_key(trans, i->btree_id, i->level,
                                old, deleted,
                                BTREE_TRIGGER_OVERWRITE|flags);
        }

        return ret;
}

static int run_one_trans_trigger(struct btree_trans *trans, struct btree_insert_entry *i,
                                 bool overwrite)
{
        /*
         * Transactional triggers create new btree_insert_entries, so we can't
         * pass them a pointer to a btree_insert_entry, that memory is going to
         * move:
         */
        struct bkey old_k = i->old_k;
        struct bkey_s_c old = { &old_k, i->old_v };
        const struct bkey_ops *old_ops = bch2_bkey_type_ops(old.k->type);
        const struct bkey_ops *new_ops = bch2_bkey_type_ops(i->k->k.type);

        verify_update_old_key(trans, i);

        if ((i->flags & BTREE_TRIGGER_NORUN) ||
            !(BTREE_NODE_TYPE_HAS_TRANS_TRIGGERS & (1U << i->bkey_type)))
                return 0;

        if (!i->insert_trigger_run &&
            !i->overwrite_trigger_run &&
            old_ops->trans_trigger == new_ops->trans_trigger) {
                i->overwrite_trigger_run = true;
                i->insert_trigger_run = true;
                return bch2_trans_mark_key(trans, i->btree_id, i->level, old, i->k,
                                           BTREE_TRIGGER_INSERT|
                                           BTREE_TRIGGER_OVERWRITE|
                                           i->flags) ?: 1;
        } else if (overwrite && !i->overwrite_trigger_run) {
                i->overwrite_trigger_run = true;
                return bch2_trans_mark_old(trans, i->btree_id, i->level, old, i->flags) ?: 1;
        } else if (!overwrite && !i->insert_trigger_run) {
                i->insert_trigger_run = true;
                return bch2_trans_mark_new(trans, i->btree_id, i->level, i->k, i->flags) ?: 1;
        } else {
                return 0;
        }
}

static int run_btree_triggers(struct btree_trans *trans, enum btree_id btree_id,
                              struct btree_insert_entry *btree_id_start)
{
        struct btree_insert_entry *i;
        bool trans_trigger_run;
        int ret, overwrite;

        for (overwrite = 1; overwrite >= 0; --overwrite) {

                /*
                 * Running triggers will append more updates to the list of updates as
                 * we're walking it:
                 */
                do {
                        trans_trigger_run = false;

                        for (i = btree_id_start;
                             i < trans->updates + trans->nr_updates && i->btree_id <= btree_id;
                             i++) {
                                if (i->btree_id != btree_id)
                                        continue;

                                ret = run_one_trans_trigger(trans, i, overwrite);
                                if (ret < 0)
                                        return ret;
                                if (ret)
                                        trans_trigger_run = true;
                        }
                } while (trans_trigger_run);
        }

        return 0;
}

static int bch2_trans_commit_run_triggers(struct btree_trans *trans)
{
        struct btree_insert_entry *i = NULL, *btree_id_start = trans->updates;
        unsigned btree_id = 0;
        int ret = 0;

        /*
         *
         * For a given btree, this algorithm runs insert triggers before
         * overwrite triggers: this is so that when extents are being moved
         * (e.g. by FALLOCATE_FL_INSERT_RANGE), we don't drop references before
         * they are re-added.
         */
        for (btree_id = 0; btree_id < BTREE_ID_NR; btree_id++) {
                if (btree_id == BTREE_ID_alloc)
                        continue;

                while (btree_id_start < trans->updates + trans->nr_updates &&
                       btree_id_start->btree_id < btree_id)
                        btree_id_start++;

                ret = run_btree_triggers(trans, btree_id, btree_id_start);
                if (ret)
                        return ret;
        }

        trans_for_each_update(trans, i) {
                if (i->btree_id > BTREE_ID_alloc)
                        break;
                if (i->btree_id == BTREE_ID_alloc) {
                        ret = run_btree_triggers(trans, BTREE_ID_alloc, i);
                        if (ret)
                                return ret;
                        break;
                }
        }

#ifdef CONFIG_BCACHEFS_DEBUG
        trans_for_each_update(trans, i)
                BUG_ON(!(i->flags & BTREE_TRIGGER_NORUN) &&
                       (BTREE_NODE_TYPE_HAS_TRANS_TRIGGERS & (1U << i->bkey_type)) &&
                       (!i->insert_trigger_run || !i->overwrite_trigger_run));
#endif
        return 0;
}

static noinline int bch2_trans_commit_run_gc_triggers(struct btree_trans *trans)
{
        struct bch_fs *c = trans->c;
        struct btree_insert_entry *i;
        int ret = 0;

        trans_for_each_update(trans, i) {
                /*
                 * XXX: synchronization of cached update triggers with gc
                 * XXX: synchronization of interior node updates with gc
                 */
                BUG_ON(i->cached || i->level);

                if (gc_visited(c, gc_pos_btree_node(insert_l(i)->b))) {
                        ret = run_one_mem_trigger(trans, i, i->flags|BTREE_TRIGGER_GC);
                        if (ret)
                                break;
                }
        }

        return ret;
}

static inline int
bch2_trans_commit_write_locked(struct btree_trans *trans, unsigned flags,
                               struct btree_insert_entry **stopped_at,
                               unsigned long trace_ip)
{
        struct bch_fs *c = trans->c;
        struct btree_insert_entry *i;
        struct btree_write_buffered_key *wb;
        struct btree_trans_commit_hook *h;
        unsigned u64s = 0;
        int ret;

        if (race_fault()) {
                trace_and_count(c, trans_restart_fault_inject, trans, trace_ip);
                return btree_trans_restart_nounlock(trans, BCH_ERR_transaction_restart_fault_inject);
        }

        /*
         * Check if the insert will fit in the leaf node with the write lock
         * held, otherwise another thread could write the node changing the
         * amount of space available:
         */

        prefetch(&trans->c->journal.flags);

        trans_for_each_update(trans, i) {
                /* Multiple inserts might go to same leaf: */
                if (!same_leaf_as_prev(trans, i))
                        u64s = 0;

                u64s += i->k->k.u64s;
                ret = !i->cached
                        ? btree_key_can_insert(trans, insert_l(i)->b, u64s)
                        : btree_key_can_insert_cached(trans, flags, i->path, u64s);
                if (ret) {
                        *stopped_at = i;
                        return ret;
                }
        }

        if (trans->nr_wb_updates &&
            trans->nr_wb_updates + c->btree_write_buffer.state.nr > c->btree_write_buffer.size)
                return -BCH_ERR_btree_insert_need_flush_buffer;

        /*
         * Don't get journal reservation until after we know insert will
         * succeed:
         */
        if (likely(!(flags & BTREE_INSERT_JOURNAL_REPLAY))) {
                ret = bch2_trans_journal_res_get(trans,
                                (flags & BCH_WATERMARK_MASK)|
                                JOURNAL_RES_GET_NONBLOCK);
                if (ret)
                        return ret;

                if (unlikely(trans->journal_transaction_names))
                        journal_transaction_name(trans);
        } else {
                trans->journal_res.seq = c->journal.replay_journal_seq;
        }

        /*
         * Not allowed to fail after we've gotten our journal reservation - we
         * have to use it:
         */

        if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG) &&
            !(flags & BTREE_INSERT_JOURNAL_REPLAY)) {
                if (bch2_journal_seq_verify)
                        trans_for_each_update(trans, i)
                                i->k->k.version.lo = trans->journal_res.seq;
                else if (bch2_inject_invalid_keys)
                        trans_for_each_update(trans, i)
                                i->k->k.version = MAX_VERSION;
        }

        if (trans->fs_usage_deltas &&
            bch2_trans_fs_usage_apply(trans, trans->fs_usage_deltas))
                return -BCH_ERR_btree_insert_need_mark_replicas;

        if (trans->nr_wb_updates) {
                EBUG_ON(flags & BTREE_INSERT_JOURNAL_REPLAY);

                ret = bch2_btree_insert_keys_write_buffer(trans);
                if (ret)
                        goto revert_fs_usage;
        }

        h = trans->hooks;
        while (h) {
                ret = h->fn(trans, h);
                if (ret)
                        goto revert_fs_usage;
                h = h->next;
        }

        trans_for_each_update(trans, i)
                if (BTREE_NODE_TYPE_HAS_MEM_TRIGGERS & (1U << i->bkey_type)) {
                        ret = run_one_mem_trigger(trans, i, i->flags);
                        if (ret)
                                goto fatal_err;
                }

        if (unlikely(c->gc_pos.phase)) {
                ret = bch2_trans_commit_run_gc_triggers(trans);
                if  (ret)
                        goto fatal_err;
        }

        if (unlikely(trans->extra_journal_entries.nr)) {
                memcpy_u64s_small(journal_res_entry(&c->journal, &trans->journal_res),
                                  trans->extra_journal_entries.data,
                                  trans->extra_journal_entries.nr);

                trans->journal_res.offset       += trans->extra_journal_entries.nr;
                trans->journal_res.u64s         -= trans->extra_journal_entries.nr;
        }

        if (likely(!(flags & BTREE_INSERT_JOURNAL_REPLAY))) {
                struct journal *j = &c->journal;
                struct jset_entry *entry;

                trans_for_each_update(trans, i) {
                        if (i->key_cache_already_flushed)
                                continue;

                        if (i->flags & BTREE_UPDATE_NOJOURNAL)
                                continue;

                        verify_update_old_key(trans, i);

                        if (trans->journal_transaction_names) {
                                entry = bch2_journal_add_entry(j, &trans->journal_res,
                                                       BCH_JSET_ENTRY_overwrite,
                                                       i->btree_id, i->level,
                                                       i->old_k.u64s);
                                bkey_reassemble((struct bkey_i *) entry->start,
                                                (struct bkey_s_c) { &i->old_k, i->old_v });
                        }

                        entry = bch2_journal_add_entry(j, &trans->journal_res,
                                               BCH_JSET_ENTRY_btree_keys,
                                               i->btree_id, i->level,
                                               i->k->k.u64s);
                        bkey_copy((struct bkey_i *) entry->start, i->k);
                }

                trans_for_each_wb_update(trans, wb) {
                        entry = bch2_journal_add_entry(j, &trans->journal_res,
                                               BCH_JSET_ENTRY_btree_keys,
                                               wb->btree, 0,
                                               wb->k.k.u64s);
                        bkey_copy((struct bkey_i *) entry->start, &wb->k);
                }

                if (trans->journal_seq)
                        *trans->journal_seq = trans->journal_res.seq;
        }

        trans_for_each_update(trans, i) {
                i->k->k.needs_whiteout = false;

                if (!i->cached) {
                        u64 seq = trans->journal_res.seq;

                        if (i->flags & BTREE_UPDATE_PREJOURNAL)
                                seq = i->seq;

                        bch2_btree_insert_key_leaf(trans, i->path, i->k, seq);
                } else if (!i->key_cache_already_flushed)
                        bch2_btree_insert_key_cached(trans, flags, i);
                else {
                        bch2_btree_key_cache_drop(trans, i->path);
                        btree_path_set_dirty(i->path, BTREE_ITER_NEED_TRAVERSE);
                }
        }

        return 0;
fatal_err:
        bch2_fatal_error(c);
revert_fs_usage:
        if (trans->fs_usage_deltas)
                bch2_trans_fs_usage_revert(trans, trans->fs_usage_deltas);
        return ret;
}

static noinline void bch2_drop_overwrites_from_journal(struct btree_trans *trans)
{
        struct btree_insert_entry *i;
        struct btree_write_buffered_key *wb;

        trans_for_each_update(trans, i)
                bch2_journal_key_overwritten(trans->c, i->btree_id, i->level, i->k->k.p);

        trans_for_each_wb_update(trans, wb)
                bch2_journal_key_overwritten(trans->c, wb->btree, 0, wb->k.k.p);
}

static noinline int bch2_trans_commit_bkey_invalid(struct btree_trans *trans,
                                                   enum bkey_invalid_flags flags,
                                                   struct btree_insert_entry *i,
                                                   struct printbuf *err)
{
        struct bch_fs *c = trans->c;

        printbuf_reset(err);
        prt_printf(err, "invalid bkey on insert from %s -> %ps",
                   trans->fn, (void *) i->ip_allocated);
        prt_newline(err);
        printbuf_indent_add(err, 2);

        bch2_bkey_val_to_text(err, c, bkey_i_to_s_c(i->k));
        prt_newline(err);

        bch2_bkey_invalid(c, bkey_i_to_s_c(i->k), i->bkey_type, flags, err);
        bch2_print_string_as_lines(KERN_ERR, err->buf);

        bch2_inconsistent_error(c);
        bch2_dump_trans_updates(trans);

        return -EINVAL;
}

/*
 * Get journal reservation, take write locks, and attempt to do btree update(s):
 */
static inline int do_bch2_trans_commit(struct btree_trans *trans, unsigned flags,
                                       struct btree_insert_entry **stopped_at,
                                       unsigned long trace_ip)
{
        struct bch_fs *c = trans->c;
        struct btree_insert_entry *i;
        int ret = 0, u64s_delta = 0;

        trans_for_each_update(trans, i) {
                if (i->cached)
                        continue;

                u64s_delta += !bkey_deleted(&i->k->k) ? i->k->k.u64s : 0;
                u64s_delta -= i->old_btree_u64s;

                if (!same_leaf_as_next(trans, i)) {
                        if (u64s_delta <= 0) {
                                ret = bch2_foreground_maybe_merge(trans, i->path,
                                                        i->level, flags);
                                if (unlikely(ret))
                                        return ret;
                        }

                        u64s_delta = 0;
                }
        }

        ret = bch2_trans_lock_write(trans);
        if (unlikely(ret))
                return ret;

        ret = bch2_trans_commit_write_locked(trans, flags, stopped_at, trace_ip);

        if (!ret && unlikely(trans->journal_replay_not_finished))
                bch2_drop_overwrites_from_journal(trans);

        bch2_trans_unlock_write(trans);

        if (!ret && trans->journal_pin)
                bch2_journal_pin_add(&c->journal, trans->journal_res.seq,
                                     trans->journal_pin, NULL);

        /*
         * Drop journal reservation after dropping write locks, since dropping
         * the journal reservation may kick off a journal write:
         */
        bch2_journal_res_put(&c->journal, &trans->journal_res);

        return ret;
}

static int journal_reclaim_wait_done(struct bch_fs *c)
{
        int ret = bch2_journal_error(&c->journal) ?:
                !bch2_btree_key_cache_must_wait(c);

        if (!ret)
                journal_reclaim_kick(&c->journal);
        return ret;
}

static noinline
int bch2_trans_commit_error(struct btree_trans *trans, unsigned flags,
                            struct btree_insert_entry *i,
                            int ret, unsigned long trace_ip)
{
        struct bch_fs *c = trans->c;

        switch (ret) {
        case -BCH_ERR_btree_insert_btree_node_full:
                ret = bch2_btree_split_leaf(trans, i->path, flags);
                if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
                        trace_and_count(c, trans_restart_btree_node_split, trans, trace_ip, i->path);
                break;
        case -BCH_ERR_btree_insert_need_mark_replicas:
                ret = drop_locks_do(trans,
                        bch2_replicas_delta_list_mark(c, trans->fs_usage_deltas));
                break;
        case -BCH_ERR_journal_res_get_blocked:
                /*
                 * XXX: this should probably be a separate BTREE_INSERT_NONBLOCK
                 * flag
                 */
                if ((flags & BTREE_INSERT_JOURNAL_RECLAIM) &&
                    (flags & BCH_WATERMARK_MASK) != BCH_WATERMARK_reclaim) {
                        ret = -BCH_ERR_journal_reclaim_would_deadlock;
                        break;
                }

                ret = drop_locks_do(trans,
                        bch2_trans_journal_res_get(trans,
                                        (flags & BCH_WATERMARK_MASK)|
                                        JOURNAL_RES_GET_CHECK));
                break;
        case -BCH_ERR_btree_insert_need_journal_reclaim:
                bch2_trans_unlock(trans);

                trace_and_count(c, trans_blocked_journal_reclaim, trans, trace_ip);

                wait_event_freezable(c->journal.reclaim_wait,
                                     (ret = journal_reclaim_wait_done(c)));
                if (ret < 0)
                        break;

                ret = bch2_trans_relock(trans);
                break;
        case -BCH_ERR_btree_insert_need_flush_buffer: {
                struct btree_write_buffer *wb = &c->btree_write_buffer;

                ret = 0;

                if (wb->state.nr > wb->size * 3 / 4) {
                        bch2_trans_unlock(trans);
                        mutex_lock(&wb->flush_lock);

                        if (wb->state.nr > wb->size * 3 / 4) {
                                bch2_trans_begin(trans);
                                ret = __bch2_btree_write_buffer_flush(trans,
                                                flags|BTREE_INSERT_NOCHECK_RW, true);
                                if (!ret) {
                                        trace_and_count(c, trans_restart_write_buffer_flush, trans, _THIS_IP_);
                                        ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_write_buffer_flush);
                                }
                        } else {
                                mutex_unlock(&wb->flush_lock);
                                ret = bch2_trans_relock(trans);
                        }
                }
                break;
        }
        default:
                BUG_ON(ret >= 0);
                break;
        }

        BUG_ON(bch2_err_matches(ret, BCH_ERR_transaction_restart) != !!trans->restarted);

        bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOSPC) &&
                                !(flags & BTREE_INSERT_NOWAIT) &&
                                (flags & BTREE_INSERT_NOFAIL), c,
                "%s: incorrectly got %s\n", __func__, bch2_err_str(ret));

        return ret;
}

static noinline int
bch2_trans_commit_get_rw_cold(struct btree_trans *trans, unsigned flags)
{
        struct bch_fs *c = trans->c;
        int ret;

        if (likely(!(flags & BTREE_INSERT_LAZY_RW)) ||
            test_bit(BCH_FS_STARTED, &c->flags))
                return -BCH_ERR_erofs_trans_commit;

        ret = drop_locks_do(trans, bch2_fs_read_write_early(c));
        if (ret)
                return ret;

        bch2_write_ref_get(c, BCH_WRITE_REF_trans);
        return 0;
}

/*
 * This is for updates done in the early part of fsck - btree_gc - before we've
 * gone RW. we only add the new key to the list of keys for journal replay to
 * do.
 */
static noinline int
do_bch2_trans_commit_to_journal_replay(struct btree_trans *trans)
{
        struct bch_fs *c = trans->c;
        struct btree_insert_entry *i;
        int ret = 0;

        trans_for_each_update(trans, i) {
                ret = bch2_journal_key_insert(c, i->btree_id, i->level, i->k);
                if (ret)
                        break;
        }

        return ret;
}

int __bch2_trans_commit(struct btree_trans *trans, unsigned flags)
{
        struct bch_fs *c = trans->c;
        struct btree_insert_entry *i = NULL;
        struct btree_write_buffered_key *wb;
        int ret = 0;

        if (!trans->nr_updates &&
            !trans->nr_wb_updates &&
            !trans->extra_journal_entries.nr)
                goto out_reset;

        if (flags & BTREE_INSERT_GC_LOCK_HELD)
                lockdep_assert_held(&c->gc_lock);

        ret = bch2_trans_commit_run_triggers(trans);
        if (ret)
                goto out_reset;

        trans_for_each_update(trans, i) {
                struct printbuf buf = PRINTBUF;
                enum bkey_invalid_flags invalid_flags = 0;

                if (!(flags & BTREE_INSERT_JOURNAL_REPLAY))
                        invalid_flags |= BKEY_INVALID_WRITE|BKEY_INVALID_COMMIT;

                if (unlikely(bch2_bkey_invalid(c, bkey_i_to_s_c(i->k),
                                               i->bkey_type, invalid_flags, &buf)))
                        ret = bch2_trans_commit_bkey_invalid(trans, invalid_flags, i, &buf);
                btree_insert_entry_checks(trans, i);
                printbuf_exit(&buf);

                if (ret)
                        return ret;
        }

        if (unlikely(!test_bit(BCH_FS_MAY_GO_RW, &c->flags))) {
                ret = do_bch2_trans_commit_to_journal_replay(trans);
                goto out_reset;
        }

        if (!(flags & BTREE_INSERT_NOCHECK_RW) &&
            unlikely(!bch2_write_ref_tryget(c, BCH_WRITE_REF_trans))) {
                ret = bch2_trans_commit_get_rw_cold(trans, flags);
                if (ret)
                        goto out_reset;
        }

        if (c->btree_write_buffer.state.nr > c->btree_write_buffer.size / 2 &&
            mutex_trylock(&c->btree_write_buffer.flush_lock)) {
                bch2_trans_begin(trans);
                bch2_trans_unlock(trans);

                ret = __bch2_btree_write_buffer_flush(trans,
                                        flags|BTREE_INSERT_NOCHECK_RW, true);
                if (!ret) {
                        trace_and_count(c, trans_restart_write_buffer_flush, trans, _THIS_IP_);
                        ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_write_buffer_flush);
                }
                goto out;
        }

        EBUG_ON(test_bit(BCH_FS_CLEAN_SHUTDOWN, &c->flags));

        trans->journal_u64s             = trans->extra_journal_entries.nr;
        trans->journal_transaction_names = READ_ONCE(c->opts.journal_transaction_names);
        if (trans->journal_transaction_names)
                trans->journal_u64s += jset_u64s(JSET_ENTRY_LOG_U64s);

        trans_for_each_update(trans, i) {
                EBUG_ON(!i->path->should_be_locked);

                ret = bch2_btree_path_upgrade(trans, i->path, i->level + 1);
                if (unlikely(ret))
                        goto out;

                EBUG_ON(!btree_node_intent_locked(i->path, i->level));

                if (i->key_cache_already_flushed)
                        continue;

                if (i->flags & BTREE_UPDATE_NOJOURNAL)
                        continue;

                /* we're going to journal the key being updated: */
                trans->journal_u64s += jset_u64s(i->k->k.u64s);

                /* and we're also going to log the overwrite: */
                if (trans->journal_transaction_names)
                        trans->journal_u64s += jset_u64s(i->old_k.u64s);
        }

        trans_for_each_wb_update(trans, wb)
                trans->journal_u64s += jset_u64s(wb->k.k.u64s);

        if (trans->extra_journal_res) {
                ret = bch2_disk_reservation_add(c, trans->disk_res,
                                trans->extra_journal_res,
                                (flags & BTREE_INSERT_NOFAIL)
                                ? BCH_DISK_RESERVATION_NOFAIL : 0);
                if (ret)
                        goto err;
        }
retry:
        bch2_trans_verify_not_in_restart(trans);
        memset(&trans->journal_res, 0, sizeof(trans->journal_res));

        ret = do_bch2_trans_commit(trans, flags, &i, _RET_IP_);

        /* make sure we didn't drop or screw up locks: */
        bch2_trans_verify_locks(trans);

        if (ret)
                goto err;

        trace_and_count(c, transaction_commit, trans, _RET_IP_);
out:
        if (likely(!(flags & BTREE_INSERT_NOCHECK_RW)))
                bch2_write_ref_put(c, BCH_WRITE_REF_trans);
out_reset:
        if (!ret)
                bch2_trans_downgrade(trans);
        bch2_trans_reset_updates(trans);

        return ret;
err:
        ret = bch2_trans_commit_error(trans, flags, i, ret, _RET_IP_);
        if (ret)
                goto out;

        goto retry;
}