]> git.sesse.net Git - bcachefs-tools-debian/blobdiff - libbcachefs/btree_update_interior.c
New upstream release
[bcachefs-tools-debian] / libbcachefs / btree_update_interior.c
index 088c320493d3c133bd1b61a8832ab3a3b3e6c754..40debf7563f8d5fdecd6185c3823d7dfda72b1cd 100644 (file)
 #include <linux/random.h>
 #include <trace/events/bcachefs.h>
 
-static void bch2_btree_insert_node(struct btree_update *, struct btree_trans *,
-                                  struct btree_path *, struct btree *,
-                                  struct keylist *, unsigned);
+static int bch2_btree_insert_node(struct btree_update *, struct btree_trans *,
+                                 struct btree_path *, struct btree *,
+                                 struct keylist *, unsigned);
 static void bch2_btree_update_add_new_node(struct btree_update *, struct btree *);
 
+static struct btree_path *get_unlocked_mut_path(struct btree_trans *trans,
+                                               enum btree_id btree_id,
+                                               unsigned level,
+                                               struct bpos pos)
+{
+       struct btree_path *path;
+
+       path = bch2_path_get(trans, btree_id, pos, level + 1, level,
+                            BTREE_ITER_NOPRESERVE|
+                            BTREE_ITER_INTENT, _RET_IP_);
+       path = bch2_btree_path_make_mut(trans, path, true, _RET_IP_);
+       bch2_btree_path_downgrade(trans, path);
+       __bch2_btree_path_unlock(trans, path);
+       return path;
+}
+
 /* Debug code: */
 
 /*
@@ -41,7 +57,7 @@ static void btree_node_interior_verify(struct bch_fs *c, struct btree *b)
        struct bkey_s_c k;
        struct bkey_s_c_btree_ptr_v2 bp;
        struct bkey unpacked;
-       char buf1[100], buf2[100];
+       struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 
        BUG_ON(!b->c.level);
 
@@ -58,9 +74,9 @@ static void btree_node_interior_verify(struct bch_fs *c, struct btree *b)
 
                if (bpos_cmp(next_node, bp.v->min_key)) {
                        bch2_dump_btree_node(c, b);
-                       panic("expected next min_key %s got %s\n",
-                             (bch2_bpos_to_text(&PBUF(buf1), next_node), buf1),
-                             (bch2_bpos_to_text(&PBUF(buf2), bp.v->min_key), buf2));
+                       bch2_bpos_to_text(&buf1, next_node);
+                       bch2_bpos_to_text(&buf2, bp.v->min_key);
+                       panic("expected next min_key %s got %s\n", buf1.buf, buf2.buf);
                }
 
                bch2_btree_node_iter_advance(&iter, b);
@@ -68,9 +84,9 @@ static void btree_node_interior_verify(struct bch_fs *c, struct btree *b)
                if (bch2_btree_node_iter_end(&iter)) {
                        if (bpos_cmp(k.k->p, b->key.k.p)) {
                                bch2_dump_btree_node(c, b);
-                               panic("expected end %s got %s\n",
-                                     (bch2_bpos_to_text(&PBUF(buf1), b->key.k.p), buf1),
-                                     (bch2_bpos_to_text(&PBUF(buf2), k.k->p), buf2));
+                               bch2_bpos_to_text(&buf1, b->key.k.p);
+                               bch2_bpos_to_text(&buf2, k.k->p);
+                               panic("expected end %s got %s\n", buf1.buf, buf2.buf);
                        }
                        break;
                }
@@ -143,7 +159,7 @@ bool bch2_btree_node_format_fits(struct bch_fs *c, struct btree *b,
 
 static void __btree_node_free(struct bch_fs *c, struct btree *b)
 {
-       trace_btree_node_free(c, b);
+       trace_and_count(c, btree_node_free, c, b);
 
        BUG_ON(btree_node_dirty(b));
        BUG_ON(btree_node_need_write(b));
@@ -160,29 +176,69 @@ static void __btree_node_free(struct bch_fs *c, struct btree *b)
 }
 
 static void bch2_btree_node_free_inmem(struct btree_trans *trans,
+                                      struct btree_path *path,
                                       struct btree *b)
 {
        struct bch_fs *c = trans->c;
-       struct btree_path *path;
+       unsigned level = b->c.level;
+
+       bch2_btree_node_lock_write_nofail(trans, path, &b->c);
+       bch2_btree_node_hash_remove(&c->btree_cache, b);
+       __btree_node_free(c, b);
+       six_unlock_write(&b->c.lock);
+       mark_btree_node_locked_noreset(path, level, SIX_LOCK_intent);
 
        trans_for_each_path(trans, path)
-               BUG_ON(path->l[b->c.level].b == b &&
-                      path->l[b->c.level].lock_seq == b->c.lock.state.seq);
+               if (path->l[level].b == b) {
+                       btree_node_unlock(trans, path, level);
+                       path->l[level].b = ERR_PTR(-BCH_ERR_no_btree_node_init);
+               }
+}
 
-       six_lock_write(&b->c.lock, NULL, NULL);
+static void bch2_btree_node_free_never_used(struct btree_update *as,
+                                           struct btree_trans *trans,
+                                           struct btree *b)
+{
+       struct bch_fs *c = as->c;
+       struct prealloc_nodes *p = &as->prealloc_nodes[b->c.lock.readers != NULL];
+       struct btree_path *path;
+       unsigned level = b->c.level;
+
+       BUG_ON(!list_empty(&b->write_blocked));
+       BUG_ON(b->will_make_reachable != (1UL|(unsigned long) as));
+
+       b->will_make_reachable = 0;
+       closure_put(&as->cl);
 
+       clear_btree_node_will_make_reachable(b);
+       clear_btree_node_accessed(b);
+       clear_btree_node_dirty_acct(c, b);
+       clear_btree_node_need_write(b);
+
+       mutex_lock(&c->btree_cache.lock);
+       list_del_init(&b->list);
        bch2_btree_node_hash_remove(&c->btree_cache, b);
-       __btree_node_free(c, b);
+       mutex_unlock(&c->btree_cache.lock);
+
+       BUG_ON(p->nr >= ARRAY_SIZE(p->b));
+       p->b[p->nr++] = b;
 
-       six_unlock_write(&b->c.lock);
        six_unlock_intent(&b->c.lock);
+
+       trans_for_each_path(trans, path)
+               if (path->l[level].b == b) {
+                       btree_node_unlock(trans, path, level);
+                       path->l[level].b = ERR_PTR(-BCH_ERR_no_btree_node_init);
+               }
 }
 
-static struct btree *__bch2_btree_node_alloc(struct bch_fs *c,
+static struct btree *__bch2_btree_node_alloc(struct btree_trans *trans,
                                             struct disk_reservation *res,
                                             struct closure *cl,
+                                            bool interior_node,
                                             unsigned flags)
 {
+       struct bch_fs *c = trans->c;
        struct write_point *wp;
        struct btree *b;
        __BKEY_PADDED(k, BKEY_BTREE_PTR_VAL_U64s_MAX) tmp;
@@ -193,10 +249,10 @@ static struct btree *__bch2_btree_node_alloc(struct bch_fs *c,
 
        if (flags & BTREE_INSERT_USE_RESERVE) {
                nr_reserve      = 0;
-               alloc_reserve   = RESERVE_BTREE_MOVINGGC;
+               alloc_reserve   = RESERVE_btree_movinggc;
        } else {
                nr_reserve      = BTREE_NODE_RESERVE;
-               alloc_reserve   = RESERVE_BTREE;
+               alloc_reserve   = RESERVE_btree;
        }
 
        mutex_lock(&c->btree_reserve_cache_lock);
@@ -212,7 +268,7 @@ static struct btree *__bch2_btree_node_alloc(struct bch_fs *c,
        mutex_unlock(&c->btree_reserve_cache_lock);
 
 retry:
-       wp = bch2_alloc_sectors_start(c,
+       wp = bch2_alloc_sectors_start_trans(trans,
                                      c->opts.metadata_target ?:
                                      c->opts.foreground_target,
                                      0,
@@ -242,7 +298,7 @@ retry:
        bch2_open_bucket_get(c, wp, &ob);
        bch2_alloc_sectors_done(c, wp);
 mem_alloc:
-       b = bch2_btree_node_mem_alloc(c);
+       b = bch2_btree_node_mem_alloc(c, interior_node);
        six_unlock_write(&b->c.lock);
        six_unlock_intent(&b->c.lock);
 
@@ -256,22 +312,25 @@ mem_alloc:
        return b;
 }
 
-static struct btree *bch2_btree_node_alloc(struct btree_update *as, unsigned level)
+static struct btree *bch2_btree_node_alloc(struct btree_update *as,
+                                          struct btree_trans *trans,
+                                          unsigned level)
 {
        struct bch_fs *c = as->c;
        struct btree *b;
+       struct prealloc_nodes *p = &as->prealloc_nodes[!!level];
        int ret;
 
        BUG_ON(level >= BTREE_MAX_DEPTH);
-       BUG_ON(!as->nr_prealloc_nodes);
+       BUG_ON(!p->nr);
 
-       b = as->prealloc_nodes[--as->nr_prealloc_nodes];
+       b = p->b[--p->nr];
 
-       six_lock_intent(&b->c.lock, NULL, NULL);
-       six_lock_write(&b->c.lock, NULL, NULL);
+       btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_intent);
+       btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_write);
 
        set_btree_node_accessed(b);
-       set_btree_node_dirty(c, b);
+       set_btree_node_dirty_acct(c, b);
        set_btree_node_need_write(b);
 
        bch2_bset_init_first(b, &b->data->keys);
@@ -301,7 +360,7 @@ static struct btree *bch2_btree_node_alloc(struct btree_update *as, unsigned lev
        ret = bch2_btree_node_hash_insert(&c->btree_cache, b, level, as->btree_id);
        BUG_ON(ret);
 
-       trace_btree_node_alloc(c, b);
+       trace_and_count(c, btree_node_alloc, c, b);
        return b;
 }
 
@@ -319,12 +378,13 @@ static void btree_set_max(struct btree *b, struct bpos pos)
 }
 
 struct btree *__bch2_btree_node_alloc_replacement(struct btree_update *as,
+                                                 struct btree_trans *trans,
                                                  struct btree *b,
                                                  struct bkey_format format)
 {
        struct btree *n;
 
-       n = bch2_btree_node_alloc(as, b->c.level);
+       n = bch2_btree_node_alloc(as, trans, b->c.level);
 
        SET_BTREE_NODE_SEQ(n->data, BTREE_NODE_SEQ(b->data) + 1);
 
@@ -343,6 +403,7 @@ struct btree *__bch2_btree_node_alloc_replacement(struct btree_update *as,
 }
 
 static struct btree *bch2_btree_node_alloc_replacement(struct btree_update *as,
+                                                      struct btree_trans *trans,
                                                       struct btree *b)
 {
        struct bkey_format new_f = bch2_btree_calc_format(b);
@@ -354,12 +415,13 @@ static struct btree *bch2_btree_node_alloc_replacement(struct btree_update *as,
        if (!bch2_btree_node_format_fits(as->c, b, &new_f))
                new_f = b->format;
 
-       return __bch2_btree_node_alloc_replacement(as, b, new_f);
+       return __bch2_btree_node_alloc_replacement(as, trans, b, new_f);
 }
 
-static struct btree *__btree_root_alloc(struct btree_update *as, unsigned level)
+static struct btree *__btree_root_alloc(struct btree_update *as,
+                               struct btree_trans *trans, unsigned level)
 {
-       struct btree *b = bch2_btree_node_alloc(as, level);
+       struct btree *b = bch2_btree_node_alloc(as, trans, level);
 
        btree_set_min(b, POS_MIN);
        btree_set_max(b, SPOS_MAX);
@@ -368,56 +430,57 @@ static struct btree *__btree_root_alloc(struct btree_update *as, unsigned level)
        btree_node_set_format(b, b->data->format);
        bch2_btree_build_aux_trees(b);
 
-       bch2_btree_update_add_new_node(as, b);
-       six_unlock_write(&b->c.lock);
-
        return b;
 }
 
-static void bch2_btree_reserve_put(struct btree_update *as)
+static void bch2_btree_reserve_put(struct btree_update *as, struct btree_trans *trans)
 {
        struct bch_fs *c = as->c;
+       struct prealloc_nodes *p;
 
-       mutex_lock(&c->btree_reserve_cache_lock);
+       for (p = as->prealloc_nodes;
+            p < as->prealloc_nodes + ARRAY_SIZE(as->prealloc_nodes);
+            p++) {
+               while (p->nr) {
+                       struct btree *b = p->b[--p->nr];
 
-       while (as->nr_prealloc_nodes) {
-               struct btree *b = as->prealloc_nodes[--as->nr_prealloc_nodes];
+                       mutex_lock(&c->btree_reserve_cache_lock);
 
-               six_lock_intent(&b->c.lock, NULL, NULL);
-               six_lock_write(&b->c.lock, NULL, NULL);
+                       if (c->btree_reserve_cache_nr <
+                           ARRAY_SIZE(c->btree_reserve_cache)) {
+                               struct btree_alloc *a =
+                                       &c->btree_reserve_cache[c->btree_reserve_cache_nr++];
 
-               if (c->btree_reserve_cache_nr <
-                   ARRAY_SIZE(c->btree_reserve_cache)) {
-                       struct btree_alloc *a =
-                               &c->btree_reserve_cache[c->btree_reserve_cache_nr++];
+                               a->ob = b->ob;
+                               b->ob.nr = 0;
+                               bkey_copy(&a->k, &b->key);
+                       } else {
+                               bch2_open_buckets_put(c, &b->ob);
+                       }
 
-                       a->ob = b->ob;
-                       b->ob.nr = 0;
-                       bkey_copy(&a->k, &b->key);
-               } else {
-                       bch2_open_buckets_put(c, &b->ob);
-               }
+                       mutex_unlock(&c->btree_reserve_cache_lock);
 
-               __btree_node_free(c, b);
-               six_unlock_write(&b->c.lock);
-               six_unlock_intent(&b->c.lock);
+                       btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_intent);
+                       btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_write);
+                       __btree_node_free(c, b);
+                       six_unlock_write(&b->c.lock);
+                       six_unlock_intent(&b->c.lock);
+               }
        }
-
-       mutex_unlock(&c->btree_reserve_cache_lock);
 }
 
-static int bch2_btree_reserve_get(struct btree_update *as, unsigned nr_nodes,
-                                 unsigned flags)
+static int bch2_btree_reserve_get(struct btree_trans *trans,
+                                 struct btree_update *as,
+                                 unsigned nr_nodes[2],
+                                 unsigned flags,
+                                 struct closure *cl)
 {
        struct bch_fs *c = as->c;
-       struct closure cl;
        struct btree *b;
-       int ret;
-
-       closure_init_stack(&cl);
-retry:
+       unsigned interior;
+       int ret = 0;
 
-       BUG_ON(nr_nodes > BTREE_RESERVE_MAX);
+       BUG_ON(nr_nodes[0] + nr_nodes[1] > BTREE_RESERVE_MAX);
 
        /*
         * Protects reaping from the btree node cache and using the btree node
@@ -426,39 +489,33 @@ retry:
         * BTREE_INSERT_NOWAIT only applies to btree node allocation, not
         * blocking on this lock:
         */
-       ret = bch2_btree_cache_cannibalize_lock(c, &cl);
+       ret = bch2_btree_cache_cannibalize_lock(c, cl);
        if (ret)
-               goto err;
+               return ret;
+
+       for (interior = 0; interior < 2; interior++) {
+               struct prealloc_nodes *p = as->prealloc_nodes + interior;
+
+               while (p->nr < nr_nodes[interior]) {
+                       b = __bch2_btree_node_alloc(trans, &as->disk_res,
+                                       flags & BTREE_INSERT_NOWAIT ? NULL : cl,
+                                       interior, flags);
+                       if (IS_ERR(b)) {
+                               ret = PTR_ERR(b);
+                               goto err;
+                       }
 
-       while (as->nr_prealloc_nodes < nr_nodes) {
-               b = __bch2_btree_node_alloc(c, &as->disk_res,
-                                           flags & BTREE_INSERT_NOWAIT
-                                           ? NULL : &cl, flags);
-               if (IS_ERR(b)) {
-                       ret = PTR_ERR(b);
-                       goto err;
+                       p->b[p->nr++] = b;
                }
-
-               as->prealloc_nodes[as->nr_prealloc_nodes++] = b;
        }
-
-       bch2_btree_cache_cannibalize_unlock(c);
-       closure_sync(&cl);
-       return 0;
 err:
        bch2_btree_cache_cannibalize_unlock(c);
-       closure_sync(&cl);
-
-       if (ret == -EAGAIN)
-               goto retry;
-
-       trace_btree_reserve_get_fail(c, nr_nodes, &cl);
        return ret;
 }
 
 /* Asynchronous interior node update machinery */
 
-static void bch2_btree_update_free(struct btree_update *as)
+static void bch2_btree_update_free(struct btree_update *as, struct btree_trans *trans)
 {
        struct bch_fs *c = as->c;
 
@@ -471,7 +528,7 @@ static void bch2_btree_update_free(struct btree_update *as)
        bch2_journal_pin_drop(&c->journal, &as->journal);
        bch2_journal_pin_flush(&c->journal, &as->journal);
        bch2_disk_reservation_put(c, &as->disk_res);
-       bch2_btree_reserve_put(as);
+       bch2_btree_reserve_put(as, trans);
 
        bch2_time_stats_update(&c->times[BCH_TIME_btree_interior_update_total],
                               as->start_time);
@@ -492,20 +549,18 @@ static void bch2_btree_update_free(struct btree_update *as)
        mutex_unlock(&c->btree_interior_update_lock);
 }
 
-static void btree_update_will_delete_key(struct btree_update *as,
-                                        struct bkey_i *k)
+static void btree_update_add_key(struct btree_update *as,
+                                struct keylist *keys, struct btree *b)
 {
-       BUG_ON(bch2_keylist_u64s(&as->old_keys) + k->k.u64s >
+       struct bkey_i *k = &b->key;
+
+       BUG_ON(bch2_keylist_u64s(keys) + k->k.u64s >
               ARRAY_SIZE(as->_old_keys));
-       bch2_keylist_add(&as->old_keys, k);
-}
 
-static void btree_update_will_add_key(struct btree_update *as,
-                                     struct bkey_i *k)
-{
-       BUG_ON(bch2_keylist_u64s(&as->new_keys) + k->k.u64s >
-              ARRAY_SIZE(as->_new_keys));
-       bch2_keylist_add(&as->new_keys, k);
+       bkey_copy(keys->top, k);
+       bkey_i_to_btree_ptr_v2(keys->top)->v.mem_ptr = b->c.level + 1;
+
+       bch2_keylist_push(keys);
 }
 
 /*
@@ -518,24 +573,29 @@ static int btree_update_nodes_written_trans(struct btree_trans *trans,
        struct bkey_i *k;
        int ret;
 
-       trans->extra_journal_entries = (void *) &as->journal_entries[0];
-       trans->extra_journal_entry_u64s = as->journal_u64s;
+       ret = darray_make_room(&trans->extra_journal_entries, as->journal_u64s);
+       if (ret)
+               return ret;
+
+       memcpy(&darray_top(trans->extra_journal_entries),
+              as->journal_entries,
+              as->journal_u64s * sizeof(u64));
+       trans->extra_journal_entries.nr += as->journal_u64s;
+
        trans->journal_pin = &as->journal;
 
-       for_each_keylist_key(&as->new_keys, k) {
-               ret = bch2_trans_mark_key(trans,
-                                         bkey_s_c_null,
-                                         bkey_i_to_s_c(k),
-                                         BTREE_TRIGGER_INSERT);
+       for_each_keylist_key(&as->old_keys, k) {
+               unsigned level = bkey_i_to_btree_ptr_v2(k)->v.mem_ptr;
+
+               ret = bch2_trans_mark_old(trans, as->btree_id, level, bkey_i_to_s_c(k), 0);
                if (ret)
                        return ret;
        }
 
-       for_each_keylist_key(&as->old_keys, k) {
-               ret = bch2_trans_mark_key(trans,
-                                         bkey_i_to_s_c(k),
-                                         bkey_s_c_null,
-                                         BTREE_TRIGGER_OVERWRITE);
+       for_each_keylist_key(&as->new_keys, k) {
+               unsigned level = bkey_i_to_btree_ptr_v2(k)->v.mem_ptr;
+
+               ret = bch2_trans_mark_new(trans, as->btree_id, level, k, 0);
                if (ret)
                        return ret;
        }
@@ -546,12 +606,13 @@ static int btree_update_nodes_written_trans(struct btree_trans *trans,
 static void btree_update_nodes_written(struct btree_update *as)
 {
        struct bch_fs *c = as->c;
-       struct btree *b = as->b;
+       struct btree *b;
        struct btree_trans trans;
        u64 journal_seq = 0;
        unsigned i;
        int ret;
 
+       bch2_trans_init(&trans, c, 0, 512);
        /*
         * If we're already in an error state, it might be because a btree node
         * was never written, and we might be trying to free that same btree
@@ -563,22 +624,21 @@ static void btree_update_nodes_written(struct btree_update *as)
        if (ret)
                goto err;
 
-       BUG_ON(!journal_pin_active(&as->journal));
-
        /*
         * Wait for any in flight writes to finish before we free the old nodes
         * on disk:
         */
        for (i = 0; i < as->nr_old_nodes; i++) {
-               struct btree *old = as->old_nodes[i];
                __le64 seq;
 
-               six_lock_read(&old->c.lock, NULL, NULL);
-               seq = old->data ? old->data->keys.seq : 0;
-               six_unlock_read(&old->c.lock);
+               b = as->old_nodes[i];
+
+               btree_node_lock_nopath_nofail(&trans, &b->c, SIX_LOCK_read);
+               seq = b->data ? b->data->keys.seq : 0;
+               six_unlock_read(&b->c.lock);
 
                if (seq == as->old_nodes_seq[i])
-                       wait_on_bit_io(&old->flags, BTREE_NODE_write_in_flight_inner,
+                       wait_on_bit_io(&b->flags, BTREE_NODE_write_in_flight_inner,
                                       TASK_UNINTERRUPTIBLE);
        }
 
@@ -595,19 +655,23 @@ static void btree_update_nodes_written(struct btree_update *as)
         * journal reclaim does btree updates when flushing bkey_cached entries,
         * which may require allocations as well.
         */
-       bch2_trans_init(&trans, c, 0, 512);
-       ret = __bch2_trans_do(&trans, &as->disk_res, &journal_seq,
-                             BTREE_INSERT_NOFAIL|
-                             BTREE_INSERT_NOCHECK_RW|
-                             BTREE_INSERT_JOURNAL_RECLAIM|
-                             BTREE_INSERT_JOURNAL_RESERVED,
-                             btree_update_nodes_written_trans(&trans, as));
-       bch2_trans_exit(&trans);
+       ret = commit_do(&trans, &as->disk_res, &journal_seq,
+                       BTREE_INSERT_NOFAIL|
+                       BTREE_INSERT_NOCHECK_RW|
+                       BTREE_INSERT_USE_RESERVE|
+                       BTREE_INSERT_JOURNAL_RECLAIM|
+                       JOURNAL_WATERMARK_reserved,
+                       btree_update_nodes_written_trans(&trans, as));
+       bch2_trans_unlock(&trans);
 
        bch2_fs_fatal_err_on(ret && !bch2_journal_error(&c->journal), c,
                             "error %i in btree_update_nodes_written()", ret);
 err:
-       if (b) {
+       if (as->b) {
+               struct btree_path *path;
+
+               b = as->b;
+               path = get_unlocked_mut_path(&trans, as->btree_id, b->c.level, b->key.k.p);
                /*
                 * @b is the node we did the final insert into:
                 *
@@ -620,11 +684,28 @@ err:
                 * we're in journal error state:
                 */
 
-               six_lock_intent(&b->c.lock, NULL, NULL);
-               six_lock_write(&b->c.lock, NULL, NULL);
+               /*
+                * Ensure transaction is unlocked before using
+                * btree_node_lock_nopath() (the use of which is always suspect,
+                * we need to work on removing this in the future)
+                *
+                * It should be, but get_unlocked_mut_path() -> bch2_path_get()
+                * calls bch2_path_upgrade(), before we call path_make_mut(), so
+                * we may rarely end up with a locked path besides the one we
+                * have here:
+                */
+               bch2_trans_unlock(&trans);
+               btree_node_lock_nopath_nofail(&trans, &b->c, SIX_LOCK_intent);
+               mark_btree_node_locked(&trans, path, b->c.level, SIX_LOCK_intent);
+               bch2_btree_path_level_init(&trans, path, b);
+
+               bch2_btree_node_lock_write_nofail(&trans, path, &b->c);
+
                mutex_lock(&c->btree_interior_update_lock);
 
                list_del(&as->write_blocked_list);
+               if (list_empty(&b->write_blocked))
+                       clear_btree_node_write_blocked(b);
 
                /*
                 * Node might have been freed, recheck under
@@ -638,8 +719,8 @@ err:
 
                        if (!ret) {
                                i->journal_seq = cpu_to_le64(
-                                       max(journal_seq,
-                                           le64_to_cpu(i->journal_seq)));
+                                                            max(journal_seq,
+                                                                le64_to_cpu(i->journal_seq)));
 
                                bch2_btree_add_journal_pin(c, b, journal_seq);
                        } else {
@@ -653,10 +734,13 @@ err:
                }
 
                mutex_unlock(&c->btree_interior_update_lock);
+
+               mark_btree_node_locked_noreset(path, b->c.level, SIX_LOCK_intent);
                six_unlock_write(&b->c.lock);
 
                btree_node_write_if_need(c, b, SIX_LOCK_intent);
-               six_unlock_intent(&b->c.lock);
+               btree_node_unlock(&trans, path, b->c.level);
+               bch2_path_put(&trans, path, true);
        }
 
        bch2_journal_pin_drop(&c->journal, &as->journal);
@@ -669,13 +753,14 @@ err:
 
                BUG_ON(b->will_make_reachable != (unsigned long) as);
                b->will_make_reachable = 0;
+               clear_btree_node_will_make_reachable(b);
        }
        mutex_unlock(&c->btree_interior_update_lock);
 
        for (i = 0; i < as->nr_new_nodes; i++) {
                b = as->new_nodes[i];
 
-               six_lock_read(&b->c.lock, NULL, NULL);
+               btree_node_lock_nopath_nofail(&trans, &b->c, SIX_LOCK_read);
                btree_node_write_if_need(c, b, SIX_LOCK_read);
                six_unlock_read(&b->c.lock);
        }
@@ -683,7 +768,8 @@ err:
        for (i = 0; i < as->nr_open_buckets; i++)
                bch2_open_bucket_put(c, c->open_buckets + as->open_buckets[i]);
 
-       bch2_btree_update_free(as);
+       bch2_btree_update_free(as, &trans);
+       bch2_trans_exit(&trans);
 }
 
 static void btree_interior_update_work(struct work_struct *work)
@@ -735,6 +821,8 @@ static void btree_update_updated_node(struct btree_update *as, struct btree *b)
 
        as->mode        = BTREE_INTERIOR_UPDATING_NODE;
        as->b           = b;
+
+       set_btree_node_write_blocked(b);
        list_add(&as->write_blocked_list, &b->write_blocked);
 
        mutex_unlock(&c->btree_interior_update_lock);
@@ -800,10 +888,19 @@ static void bch2_btree_update_add_new_node(struct btree_update *as, struct btree
 
        as->new_nodes[as->nr_new_nodes++] = b;
        b->will_make_reachable = 1UL|(unsigned long) as;
+       set_btree_node_will_make_reachable(b);
 
        mutex_unlock(&c->btree_interior_update_lock);
 
-       btree_update_will_add_key(as, &b->key);
+       btree_update_add_key(as, &as->new_keys, b);
+
+       if (b->key.k.type == KEY_TYPE_btree_ptr_v2) {
+               unsigned bytes = vstruct_end(&b->data->keys) - (void *) b->data;
+               unsigned sectors = round_up(bytes, block_bytes(c)) >> 9;
+
+               bkey_i_to_btree_ptr_v2(&b->key)->v.sectors_written =
+                       cpu_to_le16(sectors);
+       }
 }
 
 /*
@@ -822,6 +919,7 @@ static void btree_update_drop_new_node(struct bch_fs *c, struct btree *b)
         * xchg() is for synchronization with bch2_btree_complete_write:
         */
        v = xchg(&b->will_make_reachable, 0);
+       clear_btree_node_will_make_reachable(b);
        as = (struct btree_update *) (v & ~1UL);
 
        if (!as) {
@@ -855,7 +953,7 @@ static void bch2_btree_update_get_open_buckets(struct btree_update *as, struct b
  * btree_updates to point to this btree_update:
  */
 static void bch2_btree_interior_update_will_free_node(struct btree_update *as,
-                                              struct btree *b)
+                                                     struct btree *b)
 {
        struct bch_fs *c = as->c;
        struct btree_update *p, *n;
@@ -887,7 +985,7 @@ static void bch2_btree_interior_update_will_free_node(struct btree_update *as,
                closure_wake_up(&c->btree_interior_update_wait);
        }
 
-       clear_btree_node_dirty(c, b);
+       clear_btree_node_dirty_acct(c, b);
        clear_btree_node_need_write(b);
 
        /*
@@ -919,14 +1017,14 @@ static void bch2_btree_interior_update_will_free_node(struct btree_update *as,
         */
        btree_update_drop_new_node(c, b);
 
-       btree_update_will_delete_key(as, &b->key);
+       btree_update_add_key(as, &as->old_keys, b);
 
        as->old_nodes[as->nr_old_nodes] = b;
        as->old_nodes_seq[as->nr_old_nodes] = b->data->keys.seq;
        as->nr_old_nodes++;
 }
 
-static void bch2_btree_update_done(struct btree_update *as)
+static void bch2_btree_update_done(struct btree_update *as, struct btree_trans *trans)
 {
        struct bch_fs *c = as->c;
        u64 start_time = as->start_time;
@@ -937,7 +1035,7 @@ static void bch2_btree_update_done(struct btree_update *as)
                up_read(&as->c->gc_lock);
        as->took_gc_lock = false;
 
-       bch2_btree_reserve_put(as);
+       bch2_btree_reserve_put(as, trans);
 
        continue_at(&as->cl, btree_update_set_nodes_written,
                    as->c->btree_interior_update_worker);
@@ -948,32 +1046,44 @@ static void bch2_btree_update_done(struct btree_update *as)
 
 static struct btree_update *
 bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
-                       unsigned level, unsigned nr_nodes, unsigned flags)
+                       unsigned level, bool split, unsigned flags)
 {
        struct bch_fs *c = trans->c;
        struct btree_update *as;
        u64 start_time = local_clock();
        int disk_res_flags = (flags & BTREE_INSERT_NOFAIL)
                ? BCH_DISK_RESERVATION_NOFAIL : 0;
-       int journal_flags = 0;
+       unsigned nr_nodes[2] = { 0, 0 };
+       unsigned update_level = level;
+       int journal_flags = flags & JOURNAL_WATERMARK_MASK;
        int ret = 0;
+       u32 restart_count = trans->restart_count;
 
        BUG_ON(!path->should_be_locked);
 
-       if (flags & BTREE_INSERT_JOURNAL_RESERVED)
-               journal_flags |= JOURNAL_RES_GET_RESERVED;
        if (flags & BTREE_INSERT_JOURNAL_RECLAIM)
                journal_flags |= JOURNAL_RES_GET_NONBLOCK;
 
-       /*
-        * XXX: figure out how far we might need to split,
-        * instead of locking/reserving all the way to the root:
-        */
-       if (!bch2_btree_path_upgrade(trans, path, U8_MAX)) {
-               trace_trans_restart_iter_upgrade(trans->fn, _RET_IP_,
-                                                path->btree_id, &path->pos);
-               ret = btree_trans_restart(trans);
-               return ERR_PTR(ret);
+       while (1) {
+               nr_nodes[!!update_level] += 1 + split;
+               update_level++;
+
+               ret = bch2_btree_path_upgrade(trans, path, update_level + 1);
+               if (ret)
+                       return ERR_PTR(ret);
+
+               if (!btree_path_node(path, update_level)) {
+                       /* Allocating new root? */
+                       nr_nodes[1] += split;
+                       update_level = BTREE_MAX_DEPTH;
+                       break;
+               }
+
+               if (bch2_btree_node_insert_fits(c, path->l[update_level].b,
+                                       BKEY_BTREE_PTR_U64s_MAX * (1 + split)))
+                       break;
+
+               split = true;
        }
 
        if (flags & BTREE_INSERT_GC_LOCK_HELD)
@@ -981,9 +1091,10 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
        else if (!down_read_trylock(&c->gc_lock)) {
                bch2_trans_unlock(trans);
                down_read(&c->gc_lock);
-               if (!bch2_trans_relock(trans)) {
+               ret = bch2_trans_relock(trans);
+               if (ret) {
                        up_read(&c->gc_lock);
-                       return ERR_PTR(-EINTR);
+                       return ERR_PTR(ret);
                }
        }
 
@@ -995,6 +1106,7 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
        as->mode        = BTREE_INTERIOR_NO_UPDATE;
        as->took_gc_lock = !(flags & BTREE_INSERT_GC_LOCK_HELD);
        as->btree_id    = path->btree_id;
+       as->update_level = update_level;
        INIT_LIST_HEAD(&as->list);
        INIT_LIST_HEAD(&as->unwritten_list);
        INIT_LIST_HEAD(&as->write_blocked_list);
@@ -1018,41 +1130,66 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
        if (ret)
                goto err;
 
-       bch2_trans_unlock(trans);
-
        ret = bch2_journal_preres_get(&c->journal, &as->journal_preres,
                                      BTREE_UPDATE_JOURNAL_RES,
-                                     journal_flags);
+                                     journal_flags|JOURNAL_RES_GET_NONBLOCK);
        if (ret) {
-               bch2_btree_update_free(as);
-               trace_trans_restart_journal_preres_get(trans->fn, _RET_IP_);
-               btree_trans_restart(trans);
-               return ERR_PTR(ret);
+               bch2_trans_unlock(trans);
+
+               if (flags & BTREE_INSERT_JOURNAL_RECLAIM) {
+                       ret = -BCH_ERR_journal_reclaim_would_deadlock;
+                       goto err;
+               }
+
+               ret = bch2_journal_preres_get(&c->journal, &as->journal_preres,
+                                             BTREE_UPDATE_JOURNAL_RES,
+                                             journal_flags);
+               if (ret) {
+                       trace_and_count(c, trans_restart_journal_preres_get, trans, _RET_IP_, journal_flags);
+                       ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_journal_preres_get);
+                       goto err;
+               }
+
+               ret = bch2_trans_relock(trans);
+               if (ret)
+                       goto err;
        }
 
        ret = bch2_disk_reservation_get(c, &as->disk_res,
-                       nr_nodes * btree_sectors(c),
+                       (nr_nodes[0] + nr_nodes[1]) * btree_sectors(c),
                        c->opts.metadata_replicas,
                        disk_res_flags);
        if (ret)
                goto err;
 
-       ret = bch2_btree_reserve_get(as, nr_nodes, flags);
-       if (ret)
-               goto err;
+       ret = bch2_btree_reserve_get(trans, as, nr_nodes, flags, NULL);
+       if (bch2_err_matches(ret, ENOSPC) ||
+           bch2_err_matches(ret, ENOMEM)) {
+               struct closure cl;
+
+               closure_init_stack(&cl);
+
+               do {
+                       ret = bch2_btree_reserve_get(trans, as, nr_nodes, flags, &cl);
 
-       if (!bch2_trans_relock(trans)) {
-               ret = -EINTR;
+                       bch2_trans_unlock(trans);
+                       closure_sync(&cl);
+               } while (ret == -EAGAIN);
+       }
+
+       if (ret) {
+               trace_and_count(c, btree_reserve_get_fail, trans->fn, _RET_IP_, nr_nodes[0] + nr_nodes[1]);
                goto err;
        }
 
-       bch2_journal_pin_add(&c->journal,
-                            atomic64_read(&c->journal.seq),
-                            &as->journal, NULL);
+       ret = bch2_trans_relock(trans);
+       if (ret)
+               goto err;
 
+       bch2_trans_verify_not_restarted(trans, restart_count);
        return as;
 err:
-       bch2_btree_update_free(as);
+       bch2_btree_update_free(as, trans);
        return ERR_PTR(ret);
 }
 
@@ -1065,11 +1202,6 @@ static void bch2_btree_set_root_inmem(struct bch_fs *c, struct btree *b)
        list_del_init(&b->list);
        mutex_unlock(&c->btree_cache.lock);
 
-       if (b->c.level)
-               six_lock_pcpu_alloc(&b->c.lock);
-       else
-               six_lock_pcpu_free(&b->c.lock);
-
        mutex_lock(&c->btree_root_lock);
        BUG_ON(btree_node_root(c, b) &&
               (b->c.level < btree_node_root(c, b)->c.level ||
@@ -1101,9 +1233,7 @@ static void bch2_btree_set_root(struct btree_update *as,
        struct bch_fs *c = as->c;
        struct btree *old;
 
-       trace_btree_set_root(c, b);
-       BUG_ON(!b->written &&
-              !test_bit(BCH_FS_HOLD_BTREE_WRITES, &c->flags));
+       trace_and_count(c, btree_node_set_root, c, b);
 
        old = btree_node_root(c, b);
 
@@ -1111,7 +1241,7 @@ static void bch2_btree_set_root(struct btree_update *as,
         * Ensure no one is using the old root while we switch to the
         * new root:
         */
-       bch2_btree_node_lock_write(trans, path, old);
+       bch2_btree_node_lock_write_nofail(trans, path, &old->c);
 
        bch2_btree_set_root_inmem(c, b);
 
@@ -1138,7 +1268,7 @@ static void bch2_insert_fixup_btree_ptr(struct btree_update *as,
 {
        struct bch_fs *c = as->c;
        struct bkey_packed *k;
-       const char *invalid;
+       struct printbuf buf = PRINTBUF;
 
        BUG_ON(insert->k.type == KEY_TYPE_btree_ptr_v2 &&
               !btree_ptr_sectors_written(insert));
@@ -1146,13 +1276,18 @@ static void bch2_insert_fixup_btree_ptr(struct btree_update *as,
        if (unlikely(!test_bit(JOURNAL_REPLAY_DONE, &c->journal.flags)))
                bch2_journal_key_overwritten(c, b->c.btree_id, b->c.level, insert->k.p);
 
-       invalid = bch2_bkey_invalid(c, bkey_i_to_s_c(insert), btree_node_type(b)) ?:
-               bch2_bkey_in_btree_node(b, bkey_i_to_s_c(insert));
-       if (invalid) {
-               char buf[160];
-
-               bch2_bkey_val_to_text(&PBUF(buf), c, bkey_i_to_s_c(insert));
-               bch2_fs_inconsistent(c, "inserting invalid bkey %s: %s", buf, invalid);
+       if (bch2_bkey_invalid(c, bkey_i_to_s_c(insert),
+                             btree_node_type(b), WRITE, &buf) ?:
+           bch2_bkey_in_btree_node(b, bkey_i_to_s_c(insert), &buf)) {
+               printbuf_reset(&buf);
+               prt_printf(&buf, "inserting invalid bkey\n  ");
+               bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(insert));
+               prt_printf(&buf, "\n  ");
+               bch2_bkey_invalid(c, bkey_i_to_s_c(insert),
+                                 btree_node_type(b), WRITE, &buf);
+               bch2_bkey_in_btree_node(b, bkey_i_to_s_c(insert), &buf);
+
+               bch2_fs_inconsistent(c, "%s", buf.buf);
                dump_stack();
        }
 
@@ -1170,8 +1305,10 @@ static void bch2_insert_fixup_btree_ptr(struct btree_update *as,
                bch2_btree_node_iter_advance(node_iter, b);
 
        bch2_btree_bset_insert_key(trans, path, b, node_iter, insert);
-       set_btree_node_dirty(c, b);
+       set_btree_node_dirty_acct(c, b);
        set_btree_node_need_write(b);
+
+       printbuf_exit(&buf);
 }
 
 static void
@@ -1203,6 +1340,7 @@ __bch2_btree_insert_keys_interior(struct btree_update *as,
  * node)
  */
 static struct btree *__btree_split_node(struct btree_update *as,
+                                       struct btree_trans *trans,
                                        struct btree *n1)
 {
        struct bkey_format_state s;
@@ -1212,8 +1350,7 @@ static struct btree *__btree_split_node(struct btree_update *as,
        struct bkey_packed *k, *set2_start, *set2_end, *out, *prev = NULL;
        struct bpos n1_pos;
 
-       n2 = bch2_btree_node_alloc(as, n1->c.level);
-       bch2_btree_update_add_new_node(as, n2);
+       n2 = bch2_btree_node_alloc(as, trans, n1->c.level);
 
        n2->data->max_key       = n1->data->max_key;
        n2->data->format        = n1->format;
@@ -1361,38 +1498,49 @@ static void btree_split_insert_keys(struct btree_update *as,
        btree_node_interior_verify(as->c, b);
 }
 
-static void btree_split(struct btree_update *as, struct btree_trans *trans,
-                       struct btree_path *path, struct btree *b,
-                       struct keylist *keys, unsigned flags)
+static int btree_split(struct btree_update *as, struct btree_trans *trans,
+                      struct btree_path *path, struct btree *b,
+                      struct keylist *keys, unsigned flags)
 {
        struct bch_fs *c = as->c;
        struct btree *parent = btree_node_parent(path, b);
        struct btree *n1, *n2 = NULL, *n3 = NULL;
+       struct btree_path *path1 = NULL, *path2 = NULL;
        u64 start_time = local_clock();
+       int ret = 0;
 
        BUG_ON(!parent && (b != btree_node_root(c, b)));
-       BUG_ON(!btree_node_intent_locked(path, btree_node_root(c, b)->c.level));
+       BUG_ON(parent && !btree_node_intent_locked(path, b->c.level + 1));
 
        bch2_btree_interior_update_will_free_node(as, b);
 
-       n1 = bch2_btree_node_alloc_replacement(as, b);
-       bch2_btree_update_add_new_node(as, n1);
+       n1 = bch2_btree_node_alloc_replacement(as, trans, b);
 
        if (keys)
                btree_split_insert_keys(as, trans, path, n1, keys);
 
        if (bset_u64s(&n1->set[0]) > BTREE_SPLIT_THRESHOLD(c)) {
-               trace_btree_split(c, b);
+               trace_and_count(c, btree_node_split, c, b);
 
-               n2 = __btree_split_node(as, n1);
+               n2 = __btree_split_node(as, trans, n1);
 
                bch2_btree_build_aux_trees(n2);
                bch2_btree_build_aux_trees(n1);
+
+               bch2_btree_update_add_new_node(as, n1);
+               bch2_btree_update_add_new_node(as, n2);
                six_unlock_write(&n2->c.lock);
                six_unlock_write(&n1->c.lock);
 
-               bch2_btree_node_write(c, n1, SIX_LOCK_intent);
-               bch2_btree_node_write(c, n2, SIX_LOCK_intent);
+               path1 = get_unlocked_mut_path(trans, path->btree_id, n1->c.level, n1->key.k.p);
+               six_lock_increment(&n1->c.lock, SIX_LOCK_intent);
+               mark_btree_node_locked(trans, path1, n1->c.level, SIX_LOCK_intent);
+               bch2_btree_path_level_init(trans, path1, n1);
+
+               path2 = get_unlocked_mut_path(trans, path->btree_id, n2->c.level, n2->key.k.p);
+               six_lock_increment(&n2->c.lock, SIX_LOCK_intent);
+               mark_btree_node_locked(trans, path2, n2->c.level, SIX_LOCK_intent);
+               bch2_btree_path_level_init(trans, path2, n2);
 
                /*
                 * Note that on recursive parent_keys == keys, so we
@@ -1404,22 +1552,33 @@ static void btree_split(struct btree_update *as, struct btree_trans *trans,
 
                if (!parent) {
                        /* Depth increases, make a new root */
-                       n3 = __btree_root_alloc(as, b->c.level + 1);
+                       n3 = __btree_root_alloc(as, trans, b->c.level + 1);
+
+                       bch2_btree_update_add_new_node(as, n3);
+                       six_unlock_write(&n3->c.lock);
+
+                       path2->locks_want++;
+                       BUG_ON(btree_node_locked(path2, n3->c.level));
+                       six_lock_increment(&n3->c.lock, SIX_LOCK_intent);
+                       mark_btree_node_locked(trans, path2, n3->c.level, SIX_LOCK_intent);
+                       bch2_btree_path_level_init(trans, path2, n3);
 
                        n3->sib_u64s[0] = U16_MAX;
                        n3->sib_u64s[1] = U16_MAX;
 
                        btree_split_insert_keys(as, trans, path, n3, &as->parent_keys);
-
-                       bch2_btree_node_write(c, n3, SIX_LOCK_intent);
                }
        } else {
-               trace_btree_compact(c, b);
+               trace_and_count(c, btree_node_compact, c, b);
 
                bch2_btree_build_aux_trees(n1);
+               bch2_btree_update_add_new_node(as, n1);
                six_unlock_write(&n1->c.lock);
 
-               bch2_btree_node_write(c, n1, SIX_LOCK_intent);
+               path1 = get_unlocked_mut_path(trans, path->btree_id, n1->c.level, n1->key.k.p);
+               six_lock_increment(&n1->c.lock, SIX_LOCK_intent);
+               mark_btree_node_locked(trans, path1, n1->c.level, SIX_LOCK_intent);
+               bch2_btree_path_level_init(trans, path1, n1);
 
                if (parent)
                        bch2_keylist_add(&as->parent_keys, &n1->key);
@@ -1429,7 +1588,9 @@ static void btree_split(struct btree_update *as, struct btree_trans *trans,
 
        if (parent) {
                /* Split a non root node */
-               bch2_btree_insert_node(as, trans, path, parent, &as->parent_keys, flags);
+               ret = bch2_btree_insert_node(as, trans, path, parent, &as->parent_keys, flags);
+               if (ret)
+                       goto err;
        } else if (n3) {
                bch2_btree_set_root(as, trans, path, n3);
        } else {
@@ -1437,20 +1598,16 @@ static void btree_split(struct btree_update *as, struct btree_trans *trans,
                bch2_btree_set_root(as, trans, path, n1);
        }
 
-       bch2_btree_update_get_open_buckets(as, n1);
-       if (n2)
-               bch2_btree_update_get_open_buckets(as, n2);
-       if (n3)
+       if (n3) {
                bch2_btree_update_get_open_buckets(as, n3);
-
-       /* Successful split, update the path to point to the new nodes: */
-
-       six_lock_increment(&b->c.lock, SIX_LOCK_intent);
-       if (n3)
-               bch2_trans_node_add(trans, n3);
-       if (n2)
-               bch2_trans_node_add(trans, n2);
-       bch2_trans_node_add(trans, n1);
+               bch2_btree_node_write(c, n3, SIX_LOCK_intent, 0);
+       }
+       if (n2) {
+               bch2_btree_update_get_open_buckets(as, n2);
+               bch2_btree_node_write(c, n2, SIX_LOCK_intent, 0);
+       }
+       bch2_btree_update_get_open_buckets(as, n1);
+       bch2_btree_node_write(c, n1, SIX_LOCK_intent, 0);
 
        /*
         * The old node must be freed (in memory) _before_ unlocking the new
@@ -1458,13 +1615,28 @@ static void btree_split(struct btree_update *as, struct btree_trans *trans,
         * node after another thread has locked and updated the new node, thus
         * seeing stale data:
         */
-       bch2_btree_node_free_inmem(trans, b);
+       bch2_btree_node_free_inmem(trans, path, b);
+
+       if (n3)
+               bch2_trans_node_add(trans, n3);
+       if (n2)
+               bch2_trans_node_add(trans, n2);
+       bch2_trans_node_add(trans, n1);
 
        if (n3)
                six_unlock_intent(&n3->c.lock);
        if (n2)
                six_unlock_intent(&n2->c.lock);
        six_unlock_intent(&n1->c.lock);
+out:
+       if (path2) {
+               __bch2_btree_path_unlock(trans, path2);
+               bch2_path_put(trans, path2, true);
+       }
+       if (path1) {
+               __bch2_btree_path_unlock(trans, path1);
+               bch2_path_put(trans, path1, true);
+       }
 
        bch2_trans_verify_locks(trans);
 
@@ -1472,6 +1644,14 @@ static void btree_split(struct btree_update *as, struct btree_trans *trans,
                               ? BCH_TIME_btree_node_split
                               : BCH_TIME_btree_node_compact],
                               start_time);
+       return ret;
+err:
+       if (n3)
+               bch2_btree_node_free_never_used(as, trans, n3);
+       if (n2)
+               bch2_btree_node_free_never_used(as, trans, n2);
+       bch2_btree_node_free_never_used(as, trans, n1);
+       goto out;
 }
 
 static void
@@ -1506,22 +1686,30 @@ bch2_btree_insert_keys_interior(struct btree_update *as,
  * If a split occurred, this function will return early. This can only happen
  * for leaf nodes -- inserts into interior nodes have to be atomic.
  */
-static void bch2_btree_insert_node(struct btree_update *as, struct btree_trans *trans,
-                                  struct btree_path *path, struct btree *b,
-                                  struct keylist *keys, unsigned flags)
+static int bch2_btree_insert_node(struct btree_update *as, struct btree_trans *trans,
+                                 struct btree_path *path, struct btree *b,
+                                 struct keylist *keys, unsigned flags)
 {
        struct bch_fs *c = as->c;
        int old_u64s = le16_to_cpu(btree_bset_last(b)->u64s);
        int old_live_u64s = b->nr.live_u64s;
        int live_u64s_added, u64s_added;
+       int ret;
 
        lockdep_assert_held(&c->gc_lock);
-       BUG_ON(!btree_node_intent_locked(path, btree_node_root(c, b)->c.level));
+       BUG_ON(!btree_node_intent_locked(path, b->c.level));
        BUG_ON(!b->c.level);
        BUG_ON(!as || as->b);
        bch2_verify_keylist_sorted(keys);
 
-       bch2_btree_node_lock_for_insert(trans, path, b);
+       if (!(local_clock() & 63))
+               return btree_trans_restart(trans, BCH_ERR_transaction_restart_split_race);
+
+       ret = bch2_btree_node_lock_write(trans, path, &b->c);
+       if (ret)
+               return ret;
+
+       bch2_btree_node_prep_for_write(trans, path, b);
 
        if (!bch2_btree_node_insert_fits(c, b, bch2_keylist_u64s(keys))) {
                bch2_btree_node_unlock_write(trans, path, b);
@@ -1547,30 +1735,41 @@ static void bch2_btree_insert_node(struct btree_update *as, struct btree_trans *
        bch2_btree_node_unlock_write(trans, path, b);
 
        btree_node_interior_verify(c, b);
-       return;
+       return 0;
 split:
-       btree_split(as, trans, path, b, keys, flags);
+       /*
+        * We could attempt to avoid the transaction restart, by calling
+        * bch2_btree_path_upgrade() and allocating more nodes:
+        */
+       if (b->c.level >= as->update_level)
+               return btree_trans_restart(trans, BCH_ERR_transaction_restart_split_race);
+
+       return btree_split(as, trans, path, b, keys, flags);
 }
 
 int bch2_btree_split_leaf(struct btree_trans *trans,
                          struct btree_path *path,
                          unsigned flags)
 {
-       struct bch_fs *c = trans->c;
        struct btree *b = path_l(path)->b;
        struct btree_update *as;
        unsigned l;
        int ret = 0;
 
        as = bch2_btree_update_start(trans, path, path->level,
-               btree_update_reserve_required(c, b), flags);
+                                    true, flags);
        if (IS_ERR(as))
                return PTR_ERR(as);
 
-       btree_split(as, trans, path, b, NULL, flags);
-       bch2_btree_update_done(as);
+       ret = btree_split(as, trans, path, b, NULL, flags);
+       if (ret) {
+               bch2_btree_update_free(as, trans);
+               return ret;
+       }
+
+       bch2_btree_update_done(as, trans);
 
-       for (l = path->level + 1; btree_path_node(path, l) && !ret; l++)
+       for (l = path->level + 1; btree_node_intent_locked(path, l) && !ret; l++)
                ret = bch2_foreground_maybe_merge(trans, path, l, flags);
 
        return ret;
@@ -1583,7 +1782,7 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
                                  enum btree_node_sibling sib)
 {
        struct bch_fs *c = trans->c;
-       struct btree_path *sib_path = NULL;
+       struct btree_path *sib_path = NULL, *new_path = NULL;
        struct btree_update *as;
        struct bkey_format_state new_s;
        struct bkey_format new_f;
@@ -1615,7 +1814,7 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
        if (ret)
                goto err;
 
-       sib_path->should_be_locked = true;
+       btree_path_set_should_be_locked(sib_path);
 
        m = sib_path->l[level].b;
 
@@ -1634,15 +1833,17 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
        }
 
        if (bkey_cmp(bpos_successor(prev->data->max_key), next->data->min_key)) {
-               char buf1[100], buf2[100];
+               struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 
-               bch2_bpos_to_text(&PBUF(buf1), prev->data->max_key);
-               bch2_bpos_to_text(&PBUF(buf2), next->data->min_key);
+               bch2_bpos_to_text(&buf1, prev->data->max_key);
+               bch2_bpos_to_text(&buf2, next->data->min_key);
                bch_err(c,
                        "btree topology error in btree merge:\n"
                        "  prev ends at   %s\n"
                        "  next starts at %s",
-                       buf1, buf2);
+                       buf1.buf, buf2.buf);
+               printbuf_exit(&buf1);
+               printbuf_exit(&buf2);
                bch2_topology_error(c);
                ret = -EIO;
                goto err;
@@ -1672,36 +1873,42 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
                goto out;
 
        parent = btree_node_parent(path, b);
-       as = bch2_btree_update_start(trans, path, level,
-                        btree_update_reserve_required(c, parent) + 1,
-                        flags|
+       as = bch2_btree_update_start(trans, path, level, false,
                         BTREE_INSERT_NOFAIL|
-                        BTREE_INSERT_USE_RESERVE);
+                        BTREE_INSERT_USE_RESERVE|
+                        flags);
        ret = PTR_ERR_OR_ZERO(as);
        if (ret)
                goto err;
 
-       trace_btree_merge(c, b);
+       trace_and_count(c, btree_node_merge, c, b);
 
        bch2_btree_interior_update_will_free_node(as, b);
        bch2_btree_interior_update_will_free_node(as, m);
 
-       n = bch2_btree_node_alloc(as, b->c.level);
-       bch2_btree_update_add_new_node(as, n);
+       n = bch2_btree_node_alloc(as, trans, b->c.level);
+
+       SET_BTREE_NODE_SEQ(n->data,
+                          max(BTREE_NODE_SEQ(b->data),
+                              BTREE_NODE_SEQ(m->data)) + 1);
 
        btree_set_min(n, prev->data->min_key);
        btree_set_max(n, next->data->max_key);
-       n->data->format         = new_f;
 
+       n->data->format  = new_f;
        btree_node_set_format(n, new_f);
 
        bch2_btree_sort_into(c, n, prev);
        bch2_btree_sort_into(c, n, next);
 
        bch2_btree_build_aux_trees(n);
+       bch2_btree_update_add_new_node(as, n);
        six_unlock_write(&n->c.lock);
 
-       bch2_btree_node_write(c, n, SIX_LOCK_intent);
+       new_path = get_unlocked_mut_path(trans, path->btree_id, n->c.level, n->key.k.p);
+       six_lock_increment(&n->c.lock, SIX_LOCK_intent);
+       mark_btree_node_locked(trans, new_path, n->c.level, SIX_LOCK_intent);
+       bch2_btree_path_level_init(trans, new_path, n);
 
        bkey_init(&delete.k);
        delete.k.p = prev->key.k.p;
@@ -1710,32 +1917,38 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
 
        bch2_trans_verify_paths(trans);
 
-       bch2_btree_insert_node(as, trans, path, parent, &as->parent_keys, flags);
+       ret = bch2_btree_insert_node(as, trans, path, parent, &as->parent_keys, flags);
+       if (ret)
+               goto err_free_update;
 
        bch2_trans_verify_paths(trans);
 
        bch2_btree_update_get_open_buckets(as, n);
+       bch2_btree_node_write(c, n, SIX_LOCK_intent, 0);
 
-       six_lock_increment(&b->c.lock, SIX_LOCK_intent);
-       six_lock_increment(&m->c.lock, SIX_LOCK_intent);
+       bch2_btree_node_free_inmem(trans, path, b);
+       bch2_btree_node_free_inmem(trans, sib_path, m);
 
        bch2_trans_node_add(trans, n);
 
        bch2_trans_verify_paths(trans);
 
-       bch2_btree_node_free_inmem(trans, b);
-       bch2_btree_node_free_inmem(trans, m);
-
        six_unlock_intent(&n->c.lock);
 
-       bch2_btree_update_done(as);
+       bch2_btree_update_done(as, trans);
 
        bch2_time_stats_update(&c->times[BCH_TIME_btree_node_merge], start_time);
 out:
 err:
+       if (new_path)
+               bch2_path_put(trans, new_path, true);
        bch2_path_put(trans, sib_path, true);
        bch2_trans_verify_locks(trans);
        return ret;
+err_free_update:
+       bch2_btree_node_free_never_used(as, trans, n);
+       bch2_btree_update_free(as, trans);
+       goto out;
 }
 
 /**
@@ -1747,6 +1960,7 @@ int bch2_btree_node_rewrite(struct btree_trans *trans,
                            unsigned flags)
 {
        struct bch_fs *c = trans->c;
+       struct btree_path *new_path = NULL;
        struct btree *n, *parent;
        struct btree_update *as;
        int ret;
@@ -1755,47 +1969,54 @@ int bch2_btree_node_rewrite(struct btree_trans *trans,
 
        parent = btree_node_parent(iter->path, b);
        as = bch2_btree_update_start(trans, iter->path, b->c.level,
-               (parent
-                ? btree_update_reserve_required(c, parent)
-                : 0) + 1,
-               flags);
+                                    false, flags);
        ret = PTR_ERR_OR_ZERO(as);
-       if (ret) {
-               trace_btree_gc_rewrite_node_fail(c, b);
+       if (ret)
                goto out;
-       }
 
        bch2_btree_interior_update_will_free_node(as, b);
 
-       n = bch2_btree_node_alloc_replacement(as, b);
-       bch2_btree_update_add_new_node(as, n);
+       n = bch2_btree_node_alloc_replacement(as, trans, b);
 
        bch2_btree_build_aux_trees(n);
+       bch2_btree_update_add_new_node(as, n);
        six_unlock_write(&n->c.lock);
 
-       trace_btree_gc_rewrite_node(c, b);
+       new_path = get_unlocked_mut_path(trans, iter->btree_id, n->c.level, n->key.k.p);
+       six_lock_increment(&n->c.lock, SIX_LOCK_intent);
+       mark_btree_node_locked(trans, new_path, n->c.level, SIX_LOCK_intent);
+       bch2_btree_path_level_init(trans, new_path, n);
 
-       bch2_btree_node_write(c, n, SIX_LOCK_intent);
+       trace_and_count(c, btree_node_rewrite, c, b);
 
        if (parent) {
                bch2_keylist_add(&as->parent_keys, &n->key);
-               bch2_btree_insert_node(as, trans, iter->path, parent,
-                                      &as->parent_keys, flags);
+               ret = bch2_btree_insert_node(as, trans, iter->path, parent,
+                                            &as->parent_keys, flags);
+               if (ret)
+                       goto err;
        } else {
                bch2_btree_set_root(as, trans, iter->path, n);
        }
 
        bch2_btree_update_get_open_buckets(as, n);
+       bch2_btree_node_write(c, n, SIX_LOCK_intent, 0);
+
+       bch2_btree_node_free_inmem(trans, iter->path, b);
 
-       six_lock_increment(&b->c.lock, SIX_LOCK_intent);
        bch2_trans_node_add(trans, n);
-       bch2_btree_node_free_inmem(trans, b);
        six_unlock_intent(&n->c.lock);
 
-       bch2_btree_update_done(as);
+       bch2_btree_update_done(as, trans);
 out:
-       bch2_btree_path_downgrade(iter->path);
+       if (new_path)
+               bch2_path_put(trans, new_path, true);
+       bch2_btree_path_downgrade(trans, iter->path);
        return ret;
+err:
+       bch2_btree_node_free_never_used(as, trans, n);
+       bch2_btree_update_free(as, trans);
+       goto out;
 }
 
 struct async_btree_rewrite {
@@ -1825,7 +2046,7 @@ static int async_btree_node_rewrite_trans(struct btree_trans *trans,
                goto out;
 
        ret = bch2_btree_node_rewrite(trans, &iter, b, 0);
-out :
+out:
        bch2_trans_iter_exit(trans, &iter);
 
        return ret;
@@ -1847,7 +2068,7 @@ void bch2_btree_node_rewrite_async(struct bch_fs *c, struct btree *b)
 {
        struct async_btree_rewrite *a;
 
-       if (!percpu_ref_tryget(&c->writes))
+       if (!percpu_ref_tryget_live(&c->writes))
                return;
 
        a = kmalloc(sizeof(*a), GFP_NOFS);
@@ -1875,21 +2096,16 @@ static int __bch2_btree_node_update_key(struct btree_trans *trans,
        struct bch_fs *c = trans->c;
        struct btree_iter iter2 = { NULL };
        struct btree *parent;
-       u64 journal_entries[BKEY_BTREE_PTR_U64s_MAX];
        int ret;
 
        if (!skip_triggers) {
-               ret = bch2_trans_mark_key(trans,
-                                         bkey_s_c_null,
-                                         bkey_i_to_s_c(new_key),
-                                         BTREE_TRIGGER_INSERT);
+               ret = bch2_trans_mark_old(trans, b->c.btree_id, b->c.level + 1,
+                                         bkey_i_to_s_c(&b->key), 0);
                if (ret)
                        return ret;
 
-               ret = bch2_trans_mark_key(trans,
-                                         bkey_i_to_s_c(&b->key),
-                                         bkey_s_c_null,
-                                         BTREE_TRIGGER_OVERWRITE);
+               ret = bch2_trans_mark_new(trans, b->c.btree_id, b->c.level + 1,
+                                         new_key, 0);
                if (ret)
                        return ret;
        }
@@ -1912,9 +2128,9 @@ static int __bch2_btree_node_update_key(struct btree_trans *trans,
                BUG_ON(iter2.path->level != b->c.level);
                BUG_ON(bpos_cmp(iter2.path->pos, new_key->k.p));
 
-               btree_node_unlock(iter2.path, iter2.path->level);
-               path_l(iter2.path)->b = BTREE_ITER_NO_NODE_UP;
-               iter2.path->level++;
+               btree_path_set_level_up(trans, iter2.path);
+
+               bch2_btree_path_check_sort(trans, iter2.path, 0);
 
                ret   = bch2_btree_iter_traverse(&iter2) ?:
                        bch2_trans_update(trans, &iter2, new_key, BTREE_TRIGGER_NORUN);
@@ -1923,12 +2139,16 @@ static int __bch2_btree_node_update_key(struct btree_trans *trans,
        } else {
                BUG_ON(btree_node_root(c, b) != b);
 
-               trans->extra_journal_entries = (void *) &journal_entries[0];
-               trans->extra_journal_entry_u64s =
-                       journal_entry_set((void *) &journal_entries[0],
-                                         BCH_JSET_ENTRY_btree_root,
-                                         b->c.btree_id, b->c.level,
-                                         new_key, new_key->k.u64s);
+               ret = darray_make_room(&trans->extra_journal_entries,
+                                      jset_u64s(new_key->k.u64s));
+               if (ret)
+                       return ret;
+
+               journal_entry_set((void *) &darray_top(trans->extra_journal_entries),
+                                 BCH_JSET_ENTRY_btree_root,
+                                 b->c.btree_id, b->c.level,
+                                 new_key, new_key->k.u64s);
+               trans->extra_journal_entries.nr += jset_u64s(new_key->k.u64s);
        }
 
        ret = bch2_trans_commit(trans, NULL, NULL,
@@ -1936,11 +2156,11 @@ static int __bch2_btree_node_update_key(struct btree_trans *trans,
                                BTREE_INSERT_NOCHECK_RW|
                                BTREE_INSERT_USE_RESERVE|
                                BTREE_INSERT_JOURNAL_RECLAIM|
-                               BTREE_INSERT_JOURNAL_RESERVED);
+                               JOURNAL_WATERMARK_reserved);
        if (ret)
                goto err;
 
-       bch2_btree_node_lock_write(trans, iter->path, b);
+       bch2_btree_node_lock_write_nofail(trans, iter->path, &b->c);
 
        if (new_hash) {
                mutex_lock(&c->btree_cache.lock);
@@ -1978,11 +2198,9 @@ int bch2_btree_node_update_key(struct btree_trans *trans, struct btree_iter *ite
        struct closure cl;
        int ret = 0;
 
-       if (!btree_node_intent_locked(path, b->c.level) &&
-           !bch2_btree_path_upgrade(trans, path, b->c.level + 1)) {
-               btree_trans_restart(trans);
-               return -EINTR;
-       }
+       ret = bch2_btree_path_upgrade(trans, path, b->c.level + 1);
+       if (ret)
+               return ret;
 
        closure_init_stack(&cl);
 
@@ -1995,11 +2213,12 @@ int bch2_btree_node_update_key(struct btree_trans *trans, struct btree_iter *ite
                if (ret) {
                        bch2_trans_unlock(trans);
                        closure_sync(&cl);
-                       if (!bch2_trans_relock(trans))
-                               return -EINTR;
+                       ret = bch2_trans_relock(trans);
+                       if (ret)
+                               return ret;
                }
 
-               new_hash = bch2_btree_node_mem_alloc(c);
+               new_hash = bch2_btree_node_mem_alloc(c, false);
        }
 
        path->intent_ref++;
@@ -2075,7 +2294,7 @@ void bch2_btree_root_alloc(struct bch_fs *c, enum btree_id id)
                closure_sync(&cl);
        } while (ret);
 
-       b = bch2_btree_node_mem_alloc(c);
+       b = bch2_btree_node_mem_alloc(c, false);
        bch2_btree_cache_cannibalize_unlock(c);
 
        set_btree_node_fake(b);
@@ -2112,7 +2331,7 @@ void bch2_btree_updates_to_text(struct printbuf *out, struct bch_fs *c)
 
        mutex_lock(&c->btree_interior_update_lock);
        list_for_each_entry(as, &c->btree_interior_update_list, list)
-               pr_buf(out, "%p m %u w %u r %u j %llu\n",
+               prt_printf(out, "%p m %u w %u r %u j %llu\n",
                       as,
                       as->mode,
                       as->nodes_written,
@@ -2121,19 +2340,27 @@ void bch2_btree_updates_to_text(struct printbuf *out, struct bch_fs *c)
        mutex_unlock(&c->btree_interior_update_lock);
 }
 
-size_t bch2_btree_interior_updates_nr_pending(struct bch_fs *c)
+static bool bch2_btree_interior_updates_pending(struct bch_fs *c)
 {
-       size_t ret = 0;
-       struct list_head *i;
+       bool ret;
 
        mutex_lock(&c->btree_interior_update_lock);
-       list_for_each(i, &c->btree_interior_update_list)
-               ret++;
+       ret = !list_empty(&c->btree_interior_update_list);
        mutex_unlock(&c->btree_interior_update_lock);
 
        return ret;
 }
 
+bool bch2_btree_interior_updates_flush(struct bch_fs *c)
+{
+       bool ret = bch2_btree_interior_updates_pending(c);
+
+       if (ret)
+               closure_wait_event(&c->btree_interior_update_wait,
+                                  !bch2_btree_interior_updates_pending(c));
+       return ret;
+}
+
 void bch2_journal_entries_to_btree_roots(struct bch_fs *c, struct jset *jset)
 {
        struct btree_root *r;