]> git.sesse.net Git - bcachefs-tools-debian/blobdiff - libbcachefs/btree_update_leaf.c
Update bcachefs sources to fb39031ade bcachefs: bch2_sb_maybe_downgrade(), bch2_sb_up...
[bcachefs-tools-debian] / libbcachefs / btree_update_leaf.c
index a2b37dd45cf8f6d5132a9a9d224c2f5fc1a3c679..53219fdcff667b29cf86baeacc19e8fa499b4291 100644 (file)
@@ -8,6 +8,7 @@
 #include "btree_iter.h"
 #include "btree_key_cache.h"
 #include "btree_locking.h"
+#include "btree_write_buffer.h"
 #include "buckets.h"
 #include "debug.h"
 #include "errcode.h"
 #include "recovery.h"
 #include "subvolume.h"
 #include "replicas.h"
+#include "trace.h"
 
 #include <linux/prefetch.h>
 #include <linux/sort.h>
-#include <trace/events/bcachefs.h>
+
+/*
+ * bch2_btree_path_peek_slot() for a cached iterator might return a key in a
+ * different snapshot:
+ */
+static struct bkey_s_c bch2_btree_path_peek_slot_exact(struct btree_path *path, struct bkey *u)
+{
+       struct bkey_s_c k = bch2_btree_path_peek_slot(path, u);
+
+       if (k.k && bpos_eq(path->pos, k.k->p))
+               return k;
+
+       bkey_init(u);
+       u->p = path->pos;
+       return (struct bkey_s_c) { u, NULL };
+}
 
 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(i->path, &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 =
@@ -39,9 +56,10 @@ static void verify_update_old_key(struct btree_trans *trans, struct btree_insert
                        k = bkey_i_to_s_c(j_k);
        }
 
-       i->old_k.needs_whiteout = k.k->needs_whiteout;
+       u = *k.k;
+       u.needs_whiteout = i->old_k.needs_whiteout;
 
-       BUG_ON(memcmp(&i->old_k, k.k, sizeof(struct bkey)));
+       BUG_ON(memcmp(&i->old_k, &u, sizeof(struct bkey)));
        BUG_ON(i->old_v != k.v);
 #endif
 }
@@ -84,9 +102,6 @@ inline void bch2_btree_node_prep_for_write(struct btree_trans *trans,
 {
        struct bch_fs *c = trans->c;
 
-       if (path->cached)
-               return;
-
        if (unlikely(btree_node_just_written(b)) &&
            bch2_btree_post_write_cleanup(c, b))
                bch2_trans_node_reinit_iter(trans, b);
@@ -212,12 +227,12 @@ static int __btree_node_flush(struct journal *j, struct journal_entry_pin *pin,
        return 0;
 }
 
-static int btree_node_flush0(struct journal *j, struct journal_entry_pin *pin, u64 seq)
+int bch2_btree_node_flush0(struct journal *j, struct journal_entry_pin *pin, u64 seq)
 {
        return __btree_node_flush(j, pin, 0, seq);
 }
 
-static int btree_node_flush1(struct journal *j, struct journal_entry_pin *pin, u64 seq)
+int bch2_btree_node_flush1(struct journal *j, struct journal_entry_pin *pin, u64 seq)
 {
        return __btree_node_flush(j, pin, 1, seq);
 }
@@ -229,35 +244,38 @@ inline void bch2_btree_add_journal_pin(struct bch_fs *c,
 
        bch2_journal_pin_add(&c->journal, seq, &w->journal,
                             btree_node_write_idx(b) == 0
-                            ? btree_node_flush0
-                            : btree_node_flush1);
+                            ? bch2_btree_node_flush0
+                            : bch2_btree_node_flush1);
 }
 
 /**
  * btree_insert_key - insert a key one key into a leaf node
  */
-static void btree_insert_key_leaf(struct btree_trans *trans,
-                                 struct btree_insert_entry *insert)
+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 = insert_l(insert)->b;
+       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, insert->path, b,
-                                       &insert_l(insert)->iter, insert->k)))
+       if (unlikely(!bch2_btree_bset_insert_key(trans, path, b,
+                                       &path_l(path)->iter, insert)))
                return;
 
-       i->journal_seq = cpu_to_le64(max(trans->journal_res.seq,
-                                        le64_to_cpu(i->journal_seq)));
+       i->journal_seq = cpu_to_le64(max(journal_seq, le64_to_cpu(i->journal_seq)));
 
-       bch2_btree_add_journal_pin(c, b, trans->journal_res.seq);
+       bch2_btree_add_journal_pin(c, b, journal_seq);
 
-       if (unlikely(!btree_node_dirty(b)))
+       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;
@@ -272,6 +290,12 @@ static void btree_insert_key_leaf(struct btree_trans *trans,
                bch2_trans_node_reinit_iter(trans, b);
 }
 
+static void btree_insert_key_leaf(struct btree_trans *trans,
+                                 struct btree_insert_entry *insert)
+{
+       bch2_btree_insert_key_leaf(trans, insert->path, insert->k, trans->journal_res.seq);
+}
+
 /* Cached btree updates: */
 
 /* Normal update interface: */
@@ -291,40 +315,26 @@ static inline void btree_insert_entry_checks(struct btree_trans *trans,
 }
 
 static noinline int
-bch2_trans_journal_preres_get_cold(struct btree_trans *trans, unsigned u64s,
+bch2_trans_journal_preres_get_cold(struct btree_trans *trans, unsigned flags,
                                   unsigned long trace_ip)
 {
-       struct bch_fs *c = trans->c;
-       int ret;
-
-       bch2_trans_unlock(trans);
-
-       ret = bch2_journal_preres_get(&c->journal,
-                       &trans->journal_preres, u64s, 0);
-       if (ret)
-               return ret;
-
-       ret = bch2_trans_relock(trans);
-       if (ret) {
-               trace_and_count(c, trans_restart_journal_preres_get, trans, trace_ip, 0);
-               return ret;
-       }
-
-       return 0;
+       return drop_locks_do(trans,
+               bch2_journal_preres_get(&trans->c->journal,
+                       &trans->journal_preres,
+                       trans->journal_preres_u64s,
+                       (flags & BCH_WATERMARK_MASK)));
 }
 
 static __always_inline int bch2_trans_journal_res_get(struct btree_trans *trans,
-                                            unsigned flags)
+                                                     unsigned flags)
 {
        return bch2_journal_res_get(&trans->c->journal, &trans->journal_res,
-                                   trans->journal_u64s,
-                                   flags|
-                                   (trans->flags & JOURNAL_WATERMARK_MASK));
+                                   trans->journal_u64s, flags);
 }
 
 #define JSET_ENTRY_LOG_U64s            4
 
-static void journal_transaction_name(struct btree_trans *trans)
+static noinline void journal_transaction_name(struct btree_trans *trans)
 {
        struct bch_fs *c = trans->c;
        struct journal *j = &c->journal;
@@ -349,9 +359,8 @@ static inline int btree_key_can_insert(struct btree_trans *trans,
        return 0;
 }
 
-static int btree_key_can_insert_cached(struct btree_trans *trans,
-                                      struct btree_path *path,
-                                      unsigned u64s)
+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;
@@ -363,7 +372,7 @@ static int btree_key_can_insert_cached(struct btree_trans *trans,
 
        if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags) &&
            bch2_btree_key_cache_must_wait(c) &&
-           !(trans->flags & BTREE_INSERT_JOURNAL_RECLAIM))
+           !(flags & BTREE_INSERT_JOURNAL_RECLAIM))
                return -BCH_ERR_btree_insert_need_journal_reclaim;
 
        /*
@@ -380,7 +389,7 @@ static int btree_key_can_insert_cached(struct btree_trans *trans,
        if (!new_k) {
                bch_err(c, "error allocating memory for key cache key, btree %s u64s %u",
                        bch2_btree_ids[path->btree_id], new_u64s);
-               return -ENOMEM;
+               return -BCH_ERR_ENOMEM_btree_key_cache_insert;
        }
 
        trans_for_each_update(trans, i)
@@ -400,6 +409,8 @@ static int run_one_mem_trigger(struct btree_trans *trans,
 {
        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);
@@ -410,10 +421,10 @@ static int run_one_mem_trigger(struct btree_trans *trans,
        if (!btree_node_type_needs_gc(i->btree_id))
                return 0;
 
-       if (bch2_bkey_ops[old.k->type].atomic_trigger ==
-           bch2_bkey_ops[i->k->k.type].atomic_trigger &&
+       if (old_ops->atomic_trigger == new_ops->atomic_trigger &&
            ((1U << old.k->type) & BTREE_TRIGGER_WANTS_OLD_AND_NEW)) {
-               ret   = bch2_mark_key(trans, old, bkey_i_to_s_c(new),
+               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);
@@ -421,9 +432,11 @@ static int run_one_mem_trigger(struct btree_trans *trans,
 
                _deleted.p = i->path->pos;
 
-               ret   = bch2_mark_key(trans, deleted, bkey_i_to_s_c(new),
+               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, old, deleted,
+                       bch2_mark_key(trans, i->btree_id, i->level,
+                               old, deleted,
                                BTREE_TRIGGER_OVERWRITE|flags);
        }
 
@@ -440,6 +453,8 @@ static int run_one_trans_trigger(struct btree_trans *trans, struct btree_insert_
         */
        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);
 
@@ -449,8 +464,7 @@ static int run_one_trans_trigger(struct btree_trans *trans, struct btree_insert_
 
        if (!i->insert_trigger_run &&
            !i->overwrite_trigger_run &&
-           bch2_bkey_ops[old.k->type].trans_trigger ==
-           bch2_bkey_ops[i->k->k.type].trans_trigger &&
+           old_ops->trans_trigger == new_ops->trans_trigger &&
            ((1U << old.k->type) & BTREE_TRIGGER_WANTS_OLD_AND_NEW)) {
                i->overwrite_trigger_run = true;
                i->insert_trigger_run = true;
@@ -573,12 +587,13 @@ static noinline int bch2_trans_commit_run_gc_triggers(struct btree_trans *trans)
 }
 
 static inline int
-bch2_trans_commit_write_locked(struct btree_trans *trans,
+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;
        bool marking = false;
@@ -597,14 +612,6 @@ bch2_trans_commit_write_locked(struct btree_trans *trans,
 
        prefetch(&trans->c->journal.flags);
 
-       h = trans->hooks;
-       while (h) {
-               ret = h->fn(trans, h);
-               if (ret)
-                       return ret;
-               h = h->next;
-       }
-
        trans_for_each_update(trans, i) {
                /* Multiple inserts might go to same leaf: */
                if (!same_leaf_as_prev(trans, i))
@@ -613,7 +620,7 @@ bch2_trans_commit_write_locked(struct btree_trans *trans,
                u64s += i->k->k.u64s;
                ret = !i->cached
                        ? btree_key_can_insert(trans, insert_l(i)->b, u64s)
-                       : btree_key_can_insert_cached(trans, i->path, u64s);
+                       : btree_key_can_insert_cached(trans, flags, i->path, u64s);
                if (ret) {
                        *stopped_at = i;
                        return ret;
@@ -623,17 +630,23 @@ bch2_trans_commit_write_locked(struct btree_trans *trans,
                        marking = true;
        }
 
+       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(!(trans->flags & BTREE_INSERT_JOURNAL_REPLAY))) {
+       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;
 
-               journal_transaction_name(trans);
+               if (unlikely(trans->journal_transaction_names))
+                       journal_transaction_name(trans);
        } else {
                trans->journal_res.seq = c->journal.replay_journal_seq;
        }
@@ -644,7 +657,7 @@ bch2_trans_commit_write_locked(struct btree_trans *trans,
         */
 
        if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG) &&
-           !(trans->flags & BTREE_INSERT_JOURNAL_REPLAY)) {
+           !(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;
@@ -657,17 +670,33 @@ bch2_trans_commit_write_locked(struct btree_trans *trans,
            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)
-                               return ret;
+                               goto fatal_err;
                }
 
        if (unlikely(c->gc_pos.phase)) {
                ret = bch2_trans_commit_run_gc_triggers(trans);
                if  (ret)
-                       return ret;
+                       goto fatal_err;
        }
 
        if (unlikely(trans->extra_journal_entries.nr)) {
@@ -679,22 +708,27 @@ bch2_trans_commit_write_locked(struct btree_trans *trans,
                trans->journal_res.u64s         -= trans->extra_journal_entries.nr;
        }
 
-       if (likely(!(trans->flags & BTREE_INSERT_JOURNAL_REPLAY))) {
-               trans_for_each_update(trans, i) {
-                       struct journal *j = &c->journal;
-                       struct jset_entry *entry;
+       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);
 
-                       entry = bch2_journal_add_entry(j, &trans->journal_res,
-                                              BCH_JSET_ENTRY_overwrite,
-                                              i->btree_id, i->level,
-                                              i->old_k.u64s);
-                       bkey_reassemble(&entry->start[0],
-                                       (struct bkey_s_c) { &i->old_k, i->old_v });
+                       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(&entry->start[0],
+                                               (struct bkey_s_c) { &i->old_k, i->old_v });
+                       }
 
                        entry = bch2_journal_add_entry(j, &trans->journal_res,
                                               BCH_JSET_ENTRY_btree_keys,
@@ -703,6 +737,14 @@ bch2_trans_commit_write_locked(struct btree_trans *trans,
                        bkey_copy(&entry->start[0], 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(&entry->start[0], &wb->k);
+               }
+
                if (trans->journal_seq)
                        *trans->journal_seq = trans->journal_res.seq;
        }
@@ -713,13 +755,19 @@ bch2_trans_commit_write_locked(struct btree_trans *trans,
                if (!i->cached)
                        btree_insert_key_leaf(trans, i);
                else if (!i->key_cache_already_flushed)
-                       bch2_btree_insert_key_cached(trans, i->path, i->k);
+                       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;
 }
 
@@ -747,7 +795,8 @@ static inline int trans_lock_write(struct btree_trans *trans)
                if (bch2_btree_node_lock_write(trans, i->path, &insert_l(i)->b->c))
                        return trans_lock_write_fail(trans, i);
 
-               bch2_btree_node_prep_for_write(trans, i->path, insert_l(i)->b);
+               if (!i->cached)
+                       bch2_btree_node_prep_for_write(trans, i->path, insert_l(i)->b);
        }
 
        return 0;
@@ -756,18 +805,22 @@ static inline int trans_lock_write(struct btree_trans *trans)
 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);
 }
 
 #ifdef CONFIG_BCACHEFS_DEBUG
-static noinline int bch2_trans_commit_bkey_invalid(struct btree_trans *trans,
+static noinline int bch2_trans_commit_bkey_invalid(struct btree_trans *trans, unsigned flags,
                                                   struct btree_insert_entry *i,
                                                   struct printbuf *err)
 {
        struct bch_fs *c = trans->c;
-       int rw = (trans->flags & BTREE_INSERT_JOURNAL_REPLAY) ? READ : WRITE;
+       int rw = (flags & BTREE_INSERT_JOURNAL_REPLAY) ? READ : WRITE;
 
        printbuf_reset(err);
        prt_printf(err, "invalid bkey on insert from %s -> %ps",
@@ -793,26 +846,30 @@ static noinline int bch2_trans_commit_bkey_invalid(struct btree_trans *trans,
 /*
  * Get journal reservation, take write locks, and attempt to do btree update(s):
  */
-static inline int do_bch2_trans_commit(struct btree_trans *trans,
+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;
-       struct printbuf buf = PRINTBUF;
        int ret, u64s_delta = 0;
 
 #ifdef CONFIG_BCACHEFS_DEBUG
+       struct printbuf buf = PRINTBUF;
+
        trans_for_each_update(trans, i) {
-               int rw = (trans->flags & BTREE_INSERT_JOURNAL_REPLAY) ? READ : WRITE;
+               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, rw, &buf)))
-                       return bch2_trans_commit_bkey_invalid(trans, i, &buf);
+                                              i->bkey_type, invalid_flags, &buf)))
+                       return bch2_trans_commit_bkey_invalid(trans, flags, i, &buf);
                btree_insert_entry_checks(trans, i);
        }
-#endif
        printbuf_exit(&buf);
+#endif
 
        trans_for_each_update(trans, i) {
                if (i->cached)
@@ -824,7 +881,7 @@ static inline int do_bch2_trans_commit(struct btree_trans *trans,
                if (!same_leaf_as_next(trans, i)) {
                        if (u64s_delta <= 0) {
                                ret = bch2_foreground_maybe_merge(trans, i->path,
-                                                       i->level, trans->flags);
+                                                       i->level, flags);
                                if (unlikely(ret))
                                        return ret;
                        }
@@ -835,11 +892,9 @@ static inline int do_bch2_trans_commit(struct btree_trans *trans,
 
        ret = bch2_journal_preres_get(&c->journal,
                        &trans->journal_preres, trans->journal_preres_u64s,
-                       JOURNAL_RES_GET_NONBLOCK|
-                       (trans->flags & JOURNAL_WATERMARK_MASK));
+                       (flags & BCH_WATERMARK_MASK)|JOURNAL_RES_GET_NONBLOCK);
        if (unlikely(ret == -BCH_ERR_journal_preres_get_blocked))
-               ret = bch2_trans_journal_preres_get_cold(trans,
-                                               trans->journal_preres_u64s, trace_ip);
+               ret = bch2_trans_journal_preres_get_cold(trans, flags, trace_ip);
        if (unlikely(ret))
                return ret;
 
@@ -847,7 +902,7 @@ static inline int do_bch2_trans_commit(struct btree_trans *trans,
        if (unlikely(ret))
                return ret;
 
-       ret = bch2_trans_commit_write_locked(trans, stopped_at, trace_ip);
+       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);
@@ -886,7 +941,7 @@ static int journal_reclaim_wait_done(struct bch_fs *c)
 }
 
 static noinline
-int bch2_trans_commit_error(struct btree_trans *trans,
+int bch2_trans_commit_error(struct btree_trans *trans, unsigned flags,
                            struct btree_insert_entry *i,
                            int ret, unsigned long trace_ip)
 {
@@ -894,37 +949,29 @@ int bch2_trans_commit_error(struct btree_trans *trans,
 
        switch (ret) {
        case -BCH_ERR_btree_insert_btree_node_full:
-               ret = bch2_btree_split_leaf(trans, i->path, trans->flags);
+               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:
-               bch2_trans_unlock(trans);
-
-               ret = bch2_replicas_delta_list_mark(c, trans->fs_usage_deltas);
-               if (ret)
-                       break;
-
-               ret = bch2_trans_relock(trans);
-               if (ret)
-                       trace_and_count(c, trans_restart_mark_replicas, trans, trace_ip);
+               ret = drop_locks_do(trans,
+                       bch2_replicas_delta_list_mark(c, trans->fs_usage_deltas));
                break;
        case -BCH_ERR_journal_res_get_blocked:
-               bch2_trans_unlock(trans);
-
-               if ((trans->flags & BTREE_INSERT_JOURNAL_RECLAIM) &&
-                   !(trans->flags & JOURNAL_WATERMARK_reserved)) {
+               /*
+                * 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 = bch2_trans_journal_res_get(trans, JOURNAL_RES_GET_CHECK);
-               if (ret)
-                       break;
-
-               ret = bch2_trans_relock(trans);
-               if (ret)
-                       trace_and_count(c, trans_restart_journal_res_get, trans, trace_ip);
+               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);
@@ -937,9 +984,31 @@ int bch2_trans_commit_error(struct btree_trans *trans,
                        break;
 
                ret = bch2_trans_relock(trans);
-               if (ret)
-                       trace_and_count(c, trans_restart_journal_reclaim, trans, trace_ip);
                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;
@@ -948,31 +1017,28 @@ int bch2_trans_commit_error(struct btree_trans *trans,
        BUG_ON(bch2_err_matches(ret, BCH_ERR_transaction_restart) != !!trans->restarted);
 
        bch2_fs_inconsistent_on(bch2_err_matches(ret, ENOSPC) &&
-                               !(trans->flags & BTREE_INSERT_NOWAIT) &&
-                               (trans->flags & BTREE_INSERT_NOFAIL), c,
+                               !(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)
+bch2_trans_commit_get_rw_cold(struct btree_trans *trans, unsigned flags)
 {
        struct bch_fs *c = trans->c;
        int ret;
 
-       if (likely(!(trans->flags & BTREE_INSERT_LAZY_RW)) ||
+       if (likely(!(flags & BTREE_INSERT_LAZY_RW)) ||
            test_bit(BCH_FS_STARTED, &c->flags))
                return -BCH_ERR_erofs_trans_commit;
 
-       bch2_trans_unlock(trans);
-
-       ret =   bch2_fs_read_write_early(c) ?:
-               bch2_trans_relock(trans);
+       ret = drop_locks_do(trans, bch2_fs_read_write_early(c));
        if (ret)
                return ret;
 
-       percpu_ref_get(&c->writes);
+       bch2_write_ref_get(c, BCH_WRITE_REF_trans);
        return 0;
 }
 
@@ -997,18 +1063,20 @@ do_bch2_trans_commit_to_journal_replay(struct btree_trans *trans)
        return ret;
 }
 
-int __bch2_trans_commit(struct btree_trans *trans)
+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;
        unsigned u64s;
        int ret = 0;
 
        if (!trans->nr_updates &&
+           !trans->nr_wb_updates &&
            !trans->extra_journal_entries.nr)
                goto out_reset;
 
-       if (trans->flags & BTREE_INSERT_GC_LOCK_HELD)
+       if (flags & BTREE_INSERT_GC_LOCK_HELD)
                lockdep_assert_held(&c->gc_lock);
 
        ret = bch2_trans_commit_run_triggers(trans);
@@ -1020,13 +1088,27 @@ int __bch2_trans_commit(struct btree_trans *trans)
                goto out_reset;
        }
 
-       if (!(trans->flags & BTREE_INSERT_NOCHECK_RW) &&
-           unlikely(!percpu_ref_tryget_live(&c->writes))) {
-               ret = bch2_trans_commit_get_rw_cold(trans);
+       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));
 
        memset(&trans->journal_preres, 0, sizeof(trans->journal_preres));
@@ -1034,8 +1116,10 @@ int __bch2_trans_commit(struct btree_trans *trans)
        trans->journal_u64s             = trans->extra_journal_entries.nr;
        trans->journal_preres_u64s      = 0;
 
-       /* For journalling transaction name: */
-       trans->journal_u64s += jset_u64s(JSET_ENTRY_LOG_U64s);
+       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);
@@ -1052,27 +1136,35 @@ int __bch2_trans_commit(struct btree_trans *trans)
                /* we're going to journal the key being updated: */
                u64s = jset_u64s(i->k->k.u64s);
                if (i->cached &&
-                   likely(!(trans->flags & BTREE_INSERT_JOURNAL_REPLAY)))
+                   likely(!(flags & BTREE_INSERT_JOURNAL_REPLAY)))
                        trans->journal_preres_u64s += u64s;
+
+               if (i->flags & BTREE_UPDATE_NOJOURNAL)
+                       continue;
+
                trans->journal_u64s += u64s;
 
                /* and we're also going to log the overwrite: */
-               trans->journal_u64s += jset_u64s(i->old_k.u64s);
+               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,
-                               (trans->flags & BTREE_INSERT_NOFAIL)
+                               (flags & BTREE_INSERT_NOFAIL)
                                ? BCH_DISK_RESERVATION_NOFAIL : 0);
                if (ret)
                        goto err;
        }
 retry:
-       EBUG_ON(trans->restarted);
+       bch2_trans_verify_not_in_restart(trans);
        memset(&trans->journal_res, 0, sizeof(trans->journal_res));
 
-       ret = do_bch2_trans_commit(trans, &i, _RET_IP_);
+       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);
@@ -1084,22 +1176,14 @@ retry:
 out:
        bch2_journal_preres_put(&c->journal, &trans->journal_preres);
 
-       if (likely(!(trans->flags & BTREE_INSERT_NOCHECK_RW)))
-               percpu_ref_put(&c->writes);
+       if (likely(!(flags & BTREE_INSERT_NOCHECK_RW)))
+               bch2_write_ref_put(c, BCH_WRITE_REF_trans);
 out_reset:
        bch2_trans_reset_updates(trans);
 
-       if (trans->fs_usage_deltas) {
-               trans->fs_usage_deltas->used = 0;
-               memset((void *) trans->fs_usage_deltas +
-                      offsetof(struct replicas_delta_list, memset_start), 0,
-                      (void *) &trans->fs_usage_deltas->memset_end -
-                      (void *) &trans->fs_usage_deltas->memset_start);
-       }
-
        return ret;
 err:
-       ret = bch2_trans_commit_error(trans, i, ret, _RET_IP_);
+       ret = bch2_trans_commit_error(trans, flags, i, ret, _RET_IP_);
        if (ret)
                goto out;
 
@@ -1145,20 +1229,166 @@ static inline int check_pos_snapshot_overwritten(struct btree_trans *trans,
                                          struct bpos pos)
 {
        if (!btree_type_has_snapshots(id) ||
-           pos.snapshot == U32_MAX ||
            !snapshot_t(trans->c, pos.snapshot)->children[0])
                return 0;
 
        return __check_pos_snapshot_overwritten(trans, id, pos);
 }
 
+static noinline int extent_front_merge(struct btree_trans *trans,
+                                      struct btree_iter *iter,
+                                      struct bkey_s_c k,
+                                      struct bkey_i **insert,
+                                      enum btree_update_flags flags)
+{
+       struct bch_fs *c = trans->c;
+       struct bkey_i *update;
+       int ret;
+
+       update = bch2_bkey_make_mut_noupdate(trans, k);
+       ret = PTR_ERR_OR_ZERO(update);
+       if (ret)
+               return ret;
+
+       if (!bch2_bkey_merge(c, bkey_i_to_s(update), bkey_i_to_s_c(*insert)))
+               return 0;
+
+       ret =   check_pos_snapshot_overwritten(trans, iter->btree_id, k.k->p) ?:
+               check_pos_snapshot_overwritten(trans, iter->btree_id, (*insert)->k.p);
+       if (ret < 0)
+               return ret;
+       if (ret)
+               return 0;
+
+       ret = bch2_btree_delete_at(trans, iter, flags);
+       if (ret)
+               return ret;
+
+       *insert = update;
+       return 0;
+}
+
+static noinline int extent_back_merge(struct btree_trans *trans,
+                                     struct btree_iter *iter,
+                                     struct bkey_i *insert,
+                                     struct bkey_s_c k)
+{
+       struct bch_fs *c = trans->c;
+       int ret;
+
+       ret =   check_pos_snapshot_overwritten(trans, iter->btree_id, insert->k.p) ?:
+               check_pos_snapshot_overwritten(trans, iter->btree_id, k.k->p);
+       if (ret < 0)
+               return ret;
+       if (ret)
+               return 0;
+
+       bch2_bkey_merge(c, bkey_i_to_s(insert), k);
+       return 0;
+}
+
+/*
+ * When deleting, check if we need to emit a whiteout (because we're overwriting
+ * something in an ancestor snapshot)
+ */
+static int need_whiteout_for_snapshot(struct btree_trans *trans,
+                                     enum btree_id btree_id, struct bpos pos)
+{
+       struct btree_iter iter;
+       struct bkey_s_c k;
+       u32 snapshot = pos.snapshot;
+       int ret;
+
+       if (!bch2_snapshot_parent(trans->c, pos.snapshot))
+               return 0;
+
+       pos.snapshot++;
+
+       for_each_btree_key_norestart(trans, iter, btree_id, pos,
+                          BTREE_ITER_ALL_SNAPSHOTS|
+                          BTREE_ITER_NOPRESERVE, k, ret) {
+               if (!bkey_eq(k.k->p, pos))
+                       break;
+
+               if (bch2_snapshot_is_ancestor(trans->c, snapshot,
+                                             k.k->p.snapshot)) {
+                       ret = !bkey_whiteout(k.k);
+                       break;
+               }
+       }
+       bch2_trans_iter_exit(trans, &iter);
+
+       return ret;
+}
+
+int __bch2_insert_snapshot_whiteouts(struct btree_trans *trans,
+                                  enum btree_id id,
+                                  struct bpos old_pos,
+                                  struct bpos new_pos)
+{
+       struct bch_fs *c = trans->c;
+       struct btree_iter old_iter, new_iter;
+       struct bkey_s_c old_k, new_k;
+       snapshot_id_list s;
+       struct bkey_i *update;
+       int ret;
+
+       if (!bch2_snapshot_has_children(c, old_pos.snapshot))
+               return 0;
+
+       darray_init(&s);
+
+       bch2_trans_iter_init(trans, &old_iter, id, old_pos,
+                            BTREE_ITER_NOT_EXTENTS|
+                            BTREE_ITER_ALL_SNAPSHOTS);
+       while ((old_k = bch2_btree_iter_prev(&old_iter)).k &&
+              !(ret = bkey_err(old_k)) &&
+              bkey_eq(old_pos, old_k.k->p)) {
+               struct bpos whiteout_pos =
+                       SPOS(new_pos.inode, new_pos.offset, old_k.k->p.snapshot);;
+
+               if (!bch2_snapshot_is_ancestor(c, old_k.k->p.snapshot, old_pos.snapshot) ||
+                   snapshot_list_has_ancestor(c, &s, old_k.k->p.snapshot))
+                       continue;
+
+               new_k = bch2_bkey_get_iter(trans, &new_iter, id, whiteout_pos,
+                                          BTREE_ITER_NOT_EXTENTS|
+                                          BTREE_ITER_INTENT);
+               ret = bkey_err(new_k);
+               if (ret)
+                       break;
+
+               if (new_k.k->type == KEY_TYPE_deleted) {
+                       update = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
+                       ret = PTR_ERR_OR_ZERO(update);
+                       if (ret)
+                               break;
+
+                       bkey_init(&update->k);
+                       update->k.p             = whiteout_pos;
+                       update->k.type          = KEY_TYPE_whiteout;
+
+                       ret = bch2_trans_update(trans, &new_iter, update,
+                                               BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
+               }
+               bch2_trans_iter_exit(trans, &new_iter);
+
+               ret = snapshot_list_add(c, &s, old_k.k->p.snapshot);
+               if (ret)
+                       break;
+       }
+       bch2_trans_iter_exit(trans, &old_iter);
+       darray_exit(&s);
+
+       return ret;
+}
+
 int bch2_trans_update_extent(struct btree_trans *trans,
                             struct btree_iter *orig_iter,
                             struct bkey_i *insert,
                             enum btree_update_flags flags)
 {
-       struct bch_fs *c = trans->c;
-       struct btree_iter iter, update_iter;
+       struct btree_iter iter;
        struct bpos start = bkey_start_pos(&insert->k);
        struct bkey_i *update;
        struct bkey_s_c k;
@@ -1175,46 +1405,15 @@ int bch2_trans_update_extent(struct btree_trans *trans,
        if (!k.k)
                goto out;
 
-       if (bch2_bkey_maybe_mergable(k.k, &insert->k)) {
-               /*
-                * We can't merge extents if they belong to interior snapshot
-                * tree nodes, and there's a snapshot in which one extent is
-                * visible and the other is not - i.e. if visibility is
-                * different.
-                *
-                * Instead of checking if visibilitiy of the two extents is
-                * different, for now we just check if either has been
-                * overwritten:
-                */
-               ret = check_pos_snapshot_overwritten(trans, btree_id, insert->k.p);
-               if (ret < 0)
-                       goto err;
-               if (ret)
-                       goto nomerge1;
-
-               ret = check_pos_snapshot_overwritten(trans, btree_id, k.k->p);
-               if (ret < 0)
-                       goto err;
-               if (ret)
-                       goto nomerge1;
-
-               update = bch2_bkey_make_mut(trans, k);
-               if ((ret = PTR_ERR_OR_ZERO(update)))
-                       goto err;
-
-               if (bch2_bkey_merge(c, bkey_i_to_s(update), bkey_i_to_s_c(insert))) {
-                       ret = bch2_btree_delete_at(trans, &iter, flags);
+       if (bkey_eq(k.k->p, bkey_start_pos(&insert->k))) {
+               if (bch2_bkey_maybe_mergable(k.k, &insert->k)) {
+                       ret = extent_front_merge(trans, &iter, k, &insert, flags);
                        if (ret)
                                goto err;
-
-                       insert = update;
-                       goto next;
                }
-       }
-nomerge1:
-       ret = 0;
-       if (bkey_eq(k.k->p, start))
+
                goto next;
+       }
 
        while (bkey_gt(insert->k.p, bkey_start_pos(k.k))) {
                bool front_split = bkey_lt(bkey_start_pos(k.k), start);
@@ -1231,44 +1430,33 @@ nomerge1:
                        trans->extra_journal_res += compressed_sectors;
 
                if (front_split) {
-                       update = bch2_bkey_make_mut(trans, k);
+                       update = bch2_bkey_make_mut_noupdate(trans, k);
                        if ((ret = PTR_ERR_OR_ZERO(update)))
                                goto err;
 
                        bch2_cut_back(start, update);
 
-                       bch2_trans_iter_init(trans, &update_iter, btree_id, update->k.p,
-                                            BTREE_ITER_NOT_EXTENTS|
-                                            BTREE_ITER_ALL_SNAPSHOTS|
-                                            BTREE_ITER_INTENT);
-                       ret   = bch2_btree_iter_traverse(&update_iter) ?:
-                               bch2_trans_update(trans, &update_iter, update,
-                                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE|
-                                                 flags);
-                       bch2_trans_iter_exit(trans, &update_iter);
-
+                       ret =   bch2_insert_snapshot_whiteouts(trans, btree_id,
+                                               k.k->p, update->k.p) ?:
+                               bch2_btree_insert_nonextent(trans, btree_id, update,
+                                               BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE|flags);
                        if (ret)
                                goto err;
                }
 
                if (k.k->p.snapshot != insert->k.p.snapshot &&
                    (front_split || back_split)) {
-                       update = bch2_bkey_make_mut(trans, k);
+                       update = bch2_bkey_make_mut_noupdate(trans, k);
                        if ((ret = PTR_ERR_OR_ZERO(update)))
                                goto err;
 
                        bch2_cut_front(start, update);
                        bch2_cut_back(insert->k.p, update);
 
-                       bch2_trans_iter_init(trans, &update_iter, btree_id, update->k.p,
-                                            BTREE_ITER_NOT_EXTENTS|
-                                            BTREE_ITER_ALL_SNAPSHOTS|
-                                            BTREE_ITER_INTENT);
-                       ret   = bch2_btree_iter_traverse(&update_iter) ?:
-                               bch2_trans_update(trans, &update_iter, update,
-                                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE|
-                                                 flags);
-                       bch2_trans_iter_exit(trans, &update_iter);
+                       ret =   bch2_insert_snapshot_whiteouts(trans, btree_id,
+                                               k.k->p, update->k.p) ?:
+                               bch2_btree_insert_nonextent(trans, btree_id, update,
+                                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE|flags);
                        if (ret)
                                goto err;
                }
@@ -1280,27 +1468,26 @@ nomerge1:
 
                        bkey_init(&update->k);
                        update->k.p = k.k->p;
+                       update->k.p.snapshot = insert->k.p.snapshot;
 
                        if (insert->k.p.snapshot != k.k->p.snapshot) {
-                               update->k.p.snapshot = insert->k.p.snapshot;
                                update->k.type = KEY_TYPE_whiteout;
+                       } else if (btree_type_has_snapshots(btree_id)) {
+                               ret = need_whiteout_for_snapshot(trans, btree_id, update->k.p);
+                               if (ret < 0)
+                                       goto err;
+                               if (ret)
+                                       update->k.type = KEY_TYPE_whiteout;
                        }
 
-                       bch2_trans_iter_init(trans, &update_iter, btree_id, update->k.p,
-                                            BTREE_ITER_NOT_EXTENTS|
-                                            BTREE_ITER_INTENT);
-                       ret   = bch2_btree_iter_traverse(&update_iter) ?:
-                               bch2_trans_update(trans, &update_iter, update,
-                                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE|
-                                                 flags);
-                       bch2_trans_iter_exit(trans, &update_iter);
-
+                       ret = bch2_btree_insert_nonextent(trans, btree_id, update,
+                                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE|flags);
                        if (ret)
                                goto err;
                }
 
                if (back_split) {
-                       update = bch2_bkey_make_mut(trans, k);
+                       update = bch2_bkey_make_mut_noupdate(trans, k);
                        if ((ret = PTR_ERR_OR_ZERO(update)))
                                goto err;
 
@@ -1323,22 +1510,10 @@ next:
        }
 
        if (bch2_bkey_maybe_mergable(&insert->k, k.k)) {
-               ret = check_pos_snapshot_overwritten(trans, btree_id, insert->k.p);
-               if (ret < 0)
-                       goto err;
+               ret = extent_back_merge(trans, &iter, insert, k);
                if (ret)
-                       goto nomerge2;
-
-               ret = check_pos_snapshot_overwritten(trans, btree_id, k.k->p);
-               if (ret < 0)
                        goto err;
-               if (ret)
-                       goto nomerge2;
-
-               bch2_bkey_merge(c, bkey_i_to_s(insert), k);
        }
-nomerge2:
-       ret = 0;
 out:
        if (!bkey_deleted(&insert->k)) {
                /*
@@ -1358,40 +1533,6 @@ err:
        return ret;
 }
 
-/*
- * When deleting, check if we need to emit a whiteout (because we're overwriting
- * something in an ancestor snapshot)
- */
-static int need_whiteout_for_snapshot(struct btree_trans *trans,
-                                     enum btree_id btree_id, struct bpos pos)
-{
-       struct btree_iter iter;
-       struct bkey_s_c k;
-       u32 snapshot = pos.snapshot;
-       int ret;
-
-       if (!bch2_snapshot_parent(trans->c, pos.snapshot))
-               return 0;
-
-       pos.snapshot++;
-
-       for_each_btree_key_norestart(trans, iter, btree_id, pos,
-                          BTREE_ITER_ALL_SNAPSHOTS|
-                          BTREE_ITER_NOPRESERVE, k, ret) {
-               if (!bkey_eq(k.k->p, pos))
-                       break;
-
-               if (bch2_snapshot_is_ancestor(trans->c, snapshot,
-                                             k.k->p.snapshot)) {
-                       ret = !bkey_whiteout(k.k);
-                       break;
-               }
-       }
-       bch2_trans_iter_exit(trans, &iter);
-
-       return ret;
-}
-
 static int __must_check
 bch2_trans_update_by_path_trace(struct btree_trans *trans, struct btree_path *path,
                                struct bkey_i *k, enum btree_update_flags flags,
@@ -1404,21 +1545,31 @@ static noinline int flush_new_cached_update(struct btree_trans *trans,
                                            unsigned long ip)
 {
        struct btree_path *btree_path;
+       struct bkey k;
        int ret;
 
-       i->key_cache_already_flushed = true;
-       i->flags |= BTREE_TRIGGER_NORUN;
-
        btree_path = bch2_path_get(trans, path->btree_id, path->pos, 1, 0,
                                   BTREE_ITER_INTENT, _THIS_IP_);
-
        ret = bch2_btree_path_traverse(trans, btree_path, 0);
        if (ret)
-               goto err;
+               goto out;
+
+       /*
+        * The old key in the insert entry might actually refer to an existing
+        * key in the btree that has been deleted from cache and not yet
+        * flushed. Check for this and skip the flush so we don't run triggers
+        * against a stale key.
+        */
+       bch2_btree_path_peek_slot_exact(btree_path, &k);
+       if (!bkey_deleted(&k))
+               goto out;
+
+       i->key_cache_already_flushed = true;
+       i->flags |= BTREE_TRIGGER_NORUN;
 
        btree_path_set_should_be_locked(btree_path);
        ret = bch2_trans_update_by_path_trace(trans, btree_path, i->k, flags, ip);
-err:
+out:
        bch2_path_put(trans, btree_path, true);
        return ret;
 }
@@ -1476,7 +1627,7 @@ bch2_trans_update_by_path_trace(struct btree_trans *trans, struct btree_path *pa
                array_insert_item(trans->updates, trans->nr_updates,
                                  i - trans->updates, n);
 
-               i->old_v = bch2_btree_path_peek_slot(path, &i->old_k).v;
+               i->old_v = bch2_btree_path_peek_slot_exact(path, &i->old_k).v;
                i->old_btree_u64s = !bkey_deleted(&i->old_k) ? i->old_k.u64s : 0;
 
                if (unlikely(trans->journal_replay_not_finished)) {
@@ -1499,7 +1650,7 @@ bch2_trans_update_by_path_trace(struct btree_trans *trans, struct btree_path *pa
         * the key cache - but the key has to exist in the btree for that to
         * work:
         */
-       if (unlikely(path->cached && bkey_deleted(&i->old_k)))
+       if (path->cached && bkey_deleted(&i->old_k))
                return flush_new_cached_update(trans, path, i, flags, ip);
 
        return 0;
@@ -1575,6 +1726,90 @@ int __must_check bch2_trans_update(struct btree_trans *trans, struct btree_iter
        return bch2_trans_update_by_path(trans, path, k, flags);
 }
 
+int __must_check bch2_trans_update_buffered(struct btree_trans *trans,
+                                           enum btree_id btree,
+                                           struct bkey_i *k)
+{
+       struct btree_write_buffered_key *i;
+       int ret;
+
+       EBUG_ON(trans->nr_wb_updates > trans->wb_updates_size);
+       EBUG_ON(k->k.u64s > BTREE_WRITE_BUFERED_U64s_MAX);
+
+       trans_for_each_wb_update(trans, i) {
+               if (i->btree == btree && bpos_eq(i->k.k.p, k->k.p)) {
+                       bkey_copy(&i->k, k);
+                       return 0;
+               }
+       }
+
+       if (!trans->wb_updates ||
+           trans->nr_wb_updates == trans->wb_updates_size) {
+               struct btree_write_buffered_key *u;
+
+               if (trans->nr_wb_updates == trans->wb_updates_size) {
+                       struct btree_transaction_stats *s = btree_trans_stats(trans);
+
+                       BUG_ON(trans->wb_updates_size > U8_MAX / 2);
+                       trans->wb_updates_size = max(1, trans->wb_updates_size * 2);
+                       if (s)
+                               s->wb_updates_size = trans->wb_updates_size;
+               }
+
+               u = bch2_trans_kmalloc_nomemzero(trans,
+                                       trans->wb_updates_size *
+                                       sizeof(struct btree_write_buffered_key));
+               ret = PTR_ERR_OR_ZERO(u);
+               if (ret)
+                       return ret;
+
+               if (trans->nr_wb_updates)
+                       memcpy(u, trans->wb_updates, trans->nr_wb_updates *
+                              sizeof(struct btree_write_buffered_key));
+               trans->wb_updates = u;
+       }
+
+       trans->wb_updates[trans->nr_wb_updates] = (struct btree_write_buffered_key) {
+               .btree  = btree,
+       };
+
+       bkey_copy(&trans->wb_updates[trans->nr_wb_updates].k, k);
+       trans->nr_wb_updates++;
+
+       return 0;
+}
+
+int bch2_bkey_get_empty_slot(struct btree_trans *trans, struct btree_iter *iter,
+                            enum btree_id btree, struct bpos end)
+{
+       struct bkey_s_c k;
+       int ret = 0;
+
+       bch2_trans_iter_init(trans, iter, btree, POS_MAX, BTREE_ITER_INTENT);
+       k = bch2_btree_iter_prev(iter);
+       ret = bkey_err(k);
+       if (ret)
+               goto err;
+
+       bch2_btree_iter_advance(iter);
+       k = bch2_btree_iter_peek_slot(iter);
+       ret = bkey_err(k);
+       if (ret)
+               goto err;
+
+       BUG_ON(k.k->type != KEY_TYPE_deleted);
+
+       if (bkey_gt(k.k->p, end)) {
+               ret = -BCH_ERR_ENOSPC_btree_slot;
+               goto err;
+       }
+
+       return 0;
+err:
+       bch2_trans_iter_exit(trans, iter);
+       return ret;
+}
+
 void bch2_trans_commit_hook(struct btree_trans *trans,
                            struct btree_trans_commit_hook *h)
 {
@@ -1582,16 +1817,33 @@ void bch2_trans_commit_hook(struct btree_trans *trans,
        trans->hooks = h;
 }
 
-int __bch2_btree_insert(struct btree_trans *trans,
-                       enum btree_id id, struct bkey_i *k)
+int bch2_btree_insert_nonextent(struct btree_trans *trans,
+                               enum btree_id btree, struct bkey_i *k,
+                               enum btree_update_flags flags)
+{
+       struct btree_iter iter;
+       int ret;
+
+       bch2_trans_iter_init(trans, &iter, btree, k->k.p,
+                            BTREE_ITER_NOT_EXTENTS|
+                            BTREE_ITER_INTENT);
+       ret   = bch2_btree_iter_traverse(&iter) ?:
+               bch2_trans_update(trans, &iter, k, flags);
+       bch2_trans_iter_exit(trans, &iter);
+       return ret;
+}
+
+int __bch2_btree_insert(struct btree_trans *trans, enum btree_id id,
+                       struct bkey_i *k, enum btree_update_flags flags)
 {
        struct btree_iter iter;
        int ret;
 
        bch2_trans_iter_init(trans, &iter, id, bkey_start_pos(&k->k),
+                            BTREE_ITER_CACHED|
                             BTREE_ITER_INTENT);
        ret   = bch2_btree_iter_traverse(&iter) ?:
-               bch2_trans_update(trans, &iter, k, 0);
+               bch2_trans_update(trans, &iter, k, flags);
        bch2_trans_iter_exit(trans, &iter);
        return ret;
 }
@@ -1609,7 +1861,7 @@ int bch2_btree_insert(struct bch_fs *c, enum btree_id id,
                      u64 *journal_seq, int flags)
 {
        return bch2_trans_do(c, disk_res, journal_seq, flags,
-                            __bch2_btree_insert(&trans, id, k));
+                            __bch2_btree_insert(&trans, id, k, 0));
 }
 
 int bch2_btree_delete_extent_at(struct btree_trans *trans, struct btree_iter *iter,
@@ -1633,6 +1885,20 @@ int bch2_btree_delete_at(struct btree_trans *trans,
        return bch2_btree_delete_extent_at(trans, iter, 0, update_flags);
 }
 
+int bch2_btree_delete_at_buffered(struct btree_trans *trans,
+                                 enum btree_id btree, struct bpos pos)
+{
+       struct bkey_i *k;
+
+       k = bch2_trans_kmalloc(trans, sizeof(*k));
+       if (IS_ERR(k))
+               return PTR_ERR(k);
+
+       bkey_init(&k->k);
+       k->k.p = pos;
+       return bch2_trans_update_buffered(trans, btree, k);
+}
+
 int bch2_btree_delete_range_trans(struct btree_trans *trans, enum btree_id id,
                                  struct bpos start, struct bpos end,
                                  unsigned update_flags,
@@ -1671,18 +1937,10 @@ int bch2_btree_delete_range_trans(struct btree_trans *trans, enum btree_id id,
                 */
                delete.k.p = iter.pos;
 
-               if (iter.flags & BTREE_ITER_IS_EXTENTS) {
-                       unsigned max_sectors =
-                               KEY_SIZE_MAX & (~0 << trans->c->block_bits);
-
-                       /* create the biggest key we can */
-                       bch2_key_resize(&delete.k, max_sectors);
-                       bch2_cut_back(end, &delete);
-
-                       ret = bch2_extent_trim_atomic(trans, &iter, &delete);
-                       if (ret)
-                               goto err;
-               }
+               if (iter.flags & BTREE_ITER_IS_EXTENTS)
+                       bch2_key_resize(&delete.k,
+                                       bpos_min(end, k.k->p).offset -
+                                       iter.pos.offset);
 
                ret   = bch2_trans_update(trans, &iter, &delete, update_flags) ?:
                        bch2_trans_commit(trans, &disk_res, journal_seq,
@@ -1735,7 +1993,7 @@ static int __bch2_trans_log_msg(darray_u64 *entries, const char *fmt, va_list ar
        int ret;
 
        prt_vprintf(&buf, fmt, args);
-       ret = buf.allocation_failure ? -ENOMEM : 0;
+       ret = buf.allocation_failure ? -BCH_ERR_ENOMEM_trans_log_msg : 0;
        if (ret)
                goto err;
 
@@ -1763,14 +2021,19 @@ err:
        return ret;
 }
 
-int bch2_trans_log_msg(struct btree_trans *trans, const char *fmt, ...)
+static int
+__bch2_fs_log_msg(struct bch_fs *c, unsigned commit_flags, const char *fmt,
+                 va_list args)
 {
-       va_list args;
        int ret;
 
-       va_start(args, fmt);
-       ret = __bch2_trans_log_msg(&trans->extra_journal_entries, fmt, args);
-       va_end(args);
+       if (!test_bit(JOURNAL_STARTED, &c->journal.flags)) {
+               ret = __bch2_trans_log_msg(&c->journal.early_journal_entries, fmt, args);
+       } else {
+               ret = bch2_trans_do(c, NULL, NULL,
+                       BTREE_INSERT_LAZY_RW|commit_flags,
+                       __bch2_trans_log_msg(&trans.extra_journal_entries, fmt, args));
+       }
 
        return ret;
 }
@@ -1781,16 +2044,22 @@ int bch2_fs_log_msg(struct bch_fs *c, const char *fmt, ...)
        int ret;
 
        va_start(args, fmt);
+       ret = __bch2_fs_log_msg(c, 0, fmt, args);
+       va_end(args);
+       return ret;
+}
 
-       if (!test_bit(JOURNAL_STARTED, &c->journal.flags)) {
-               ret = __bch2_trans_log_msg(&c->journal.early_journal_entries, fmt, args);
-       } else {
-               ret = bch2_trans_do(c, NULL, NULL, BTREE_INSERT_LAZY_RW,
-                       __bch2_trans_log_msg(&trans.extra_journal_entries, fmt, args));
-       }
+/*
+ * Use for logging messages during recovery to enable reserved space and avoid
+ * blocking.
+ */
+int bch2_journal_log_msg(struct bch_fs *c, const char *fmt, ...)
+{
+       va_list args;
+       int ret;
 
+       va_start(args, fmt);
+       ret = __bch2_fs_log_msg(c, BCH_WATERMARK_reclaim, fmt, args);
        va_end(args);
-
        return ret;
-
 }