]> git.sesse.net Git - bcachefs-tools-debian/blobdiff - libbcachefs/btree_update_interior.c
New upstream snapshot
[bcachefs-tools-debian] / libbcachefs / btree_update_interior.c
index c8c3382f48c7e31ded2872dbf34af9057306cff9..088c320493d3c133bd1b61a8832ab3a3b3e6c754 100644 (file)
@@ -16,6 +16,7 @@
 #include "journal.h"
 #include "journal_reclaim.h"
 #include "keylist.h"
+#include "recovery.h"
 #include "replicas.h"
 #include "super-io.h"
 
@@ -23,8 +24,9 @@
 #include <trace/events/bcachefs.h>
 
 static void bch2_btree_insert_node(struct btree_update *, struct btree_trans *,
-                                  struct btree_iter *, struct btree *,
+                                  struct btree_path *, struct btree *,
                                   struct keylist *, unsigned);
+static void bch2_btree_update_add_new_node(struct btree_update *, struct btree *);
 
 /* Debug code: */
 
@@ -43,7 +45,7 @@ static void btree_node_interior_verify(struct bch_fs *c, struct btree *b)
 
        BUG_ON(!b->c.level);
 
-       if (!test_bit(BCH_FS_BTREE_INTERIOR_REPLAY_DONE, &c->flags))
+       if (!test_bit(JOURNAL_REPLAY_DONE, &c->journal.flags))
                return;
 
        bch2_btree_node_iter_init_from_start(&iter, b);
@@ -152,38 +154,26 @@ static void __btree_node_free(struct bch_fs *c, struct btree *b)
 
        clear_btree_node_noevict(b);
 
-       bch2_btree_node_hash_remove(&c->btree_cache, b);
-
        mutex_lock(&c->btree_cache.lock);
        list_move(&b->list, &c->btree_cache.freeable);
        mutex_unlock(&c->btree_cache.lock);
 }
 
-void bch2_btree_node_free_never_inserted(struct bch_fs *c, struct btree *b)
+static void bch2_btree_node_free_inmem(struct btree_trans *trans,
+                                      struct btree *b)
 {
-       struct open_buckets ob = b->ob;
+       struct bch_fs *c = trans->c;
+       struct btree_path *path;
 
-       b->ob.nr = 0;
+       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);
 
-       clear_btree_node_dirty(c, b);
+       six_lock_write(&b->c.lock, NULL, NULL);
 
-       btree_node_lock_type(c, b, SIX_LOCK_write);
+       bch2_btree_node_hash_remove(&c->btree_cache, b);
        __btree_node_free(c, b);
-       six_unlock_write(&b->c.lock);
 
-       bch2_open_buckets_put(c, &ob);
-}
-
-void bch2_btree_node_free_inmem(struct bch_fs *c, struct btree *b,
-                               struct btree_iter *iter)
-{
-       struct btree_iter *linked;
-
-       trans_for_each_iter(iter->trans, linked)
-               BUG_ON(linked->l[b->c.level].b == b);
-
-       six_lock_write(&b->c.lock, NULL, NULL);
-       __btree_node_free(c, b);
        six_unlock_write(&b->c.lock);
        six_unlock_intent(&b->c.lock);
 }
@@ -234,12 +224,12 @@ retry:
        if (IS_ERR(wp))
                return ERR_CAST(wp);
 
-       if (wp->sectors_free < c->opts.btree_node_size) {
+       if (wp->sectors_free < btree_sectors(c)) {
                struct open_bucket *ob;
                unsigned i;
 
                open_bucket_for_each(c, &wp->ptrs, ob, i)
-                       if (ob->sectors_free < c->opts.btree_node_size)
+                       if (ob->sectors_free < btree_sectors(c))
                                ob->sectors_free = 0;
 
                bch2_alloc_sectors_done(c, wp);
@@ -247,12 +237,14 @@ retry:
        }
 
        bkey_btree_ptr_v2_init(&tmp.k);
-       bch2_alloc_sectors_append_ptrs(c, wp, &tmp.k, c->opts.btree_node_size);
+       bch2_alloc_sectors_append_ptrs(c, wp, &tmp.k, btree_sectors(c), false);
 
        bch2_open_bucket_get(c, wp, &ob);
        bch2_alloc_sectors_done(c, wp);
 mem_alloc:
        b = bch2_btree_node_mem_alloc(c);
+       six_unlock_write(&b->c.lock);
+       six_unlock_intent(&b->c.lock);
 
        /* we hold cannibalize_lock: */
        BUG_ON(IS_ERR(b));
@@ -275,6 +267,9 @@ static struct btree *bch2_btree_node_alloc(struct btree_update *as, unsigned lev
 
        b = as->prealloc_nodes[--as->nr_prealloc_nodes];
 
+       six_lock_intent(&b->c.lock, NULL, NULL);
+       six_lock_write(&b->c.lock, NULL, NULL);
+
        set_btree_node_accessed(b);
        set_btree_node_dirty(c, b);
        set_btree_node_need_write(b);
@@ -388,7 +383,8 @@ static void bch2_btree_reserve_put(struct btree_update *as)
        while (as->nr_prealloc_nodes) {
                struct btree *b = as->prealloc_nodes[--as->nr_prealloc_nodes];
 
-               six_unlock_write(&b->c.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)) {
@@ -402,10 +398,8 @@ static void bch2_btree_reserve_put(struct btree_update *as)
                        bch2_open_buckets_put(c, &b->ob);
                }
 
-               btree_node_lock_type(c, b, SIX_LOCK_write);
                __btree_node_free(c, b);
                six_unlock_write(&b->c.lock);
-
                six_unlock_intent(&b->c.lock);
        }
 
@@ -413,39 +407,52 @@ static void bch2_btree_reserve_put(struct btree_update *as)
 }
 
 static int bch2_btree_reserve_get(struct btree_update *as, unsigned nr_nodes,
-                                 unsigned flags, struct closure *cl)
+                                 unsigned flags)
 {
        struct bch_fs *c = as->c;
+       struct closure cl;
        struct btree *b;
        int ret;
 
+       closure_init_stack(&cl);
+retry:
+
        BUG_ON(nr_nodes > BTREE_RESERVE_MAX);
 
        /*
         * Protects reaping from the btree node cache and using the btree node
         * open bucket reserve:
+        *
+        * 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)
-               return ret;
+               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);
+                                           ? NULL : &cl, flags);
                if (IS_ERR(b)) {
                        ret = PTR_ERR(b);
-                       goto err_free;
+                       goto err;
                }
 
                as->prealloc_nodes[as->nr_prealloc_nodes++] = b;
        }
 
        bch2_btree_cache_cannibalize_unlock(c);
+       closure_sync(&cl);
        return 0;
-err_free:
+err:
        bch2_btree_cache_cannibalize_unlock(c);
-       trace_btree_reserve_get_fail(c, nr_nodes, cl);
+       closure_sync(&cl);
+
+       if (ret == -EAGAIN)
+               goto retry;
+
+       trace_btree_reserve_get_fail(c, nr_nodes, &cl);
        return ret;
 }
 
@@ -466,15 +473,23 @@ static void bch2_btree_update_free(struct btree_update *as)
        bch2_disk_reservation_put(c, &as->disk_res);
        bch2_btree_reserve_put(as);
 
+       bch2_time_stats_update(&c->times[BCH_TIME_btree_interior_update_total],
+                              as->start_time);
+
        mutex_lock(&c->btree_interior_update_lock);
        list_del(&as->unwritten_list);
        list_del(&as->list);
-       mutex_unlock(&c->btree_interior_update_lock);
 
        closure_debug_destroy(&as->cl);
        mempool_free(as, &c->btree_interior_update_pool);
 
+       /*
+        * Have to do the wakeup with btree_interior_update_lock still held,
+        * since being on btree_interior_update_list is our ref on @c:
+        */
        closure_wake_up(&c->btree_interior_update_wait);
+
+       mutex_unlock(&c->btree_interior_update_lock);
 }
 
 static void btree_update_will_delete_key(struct btree_update *as,
@@ -605,8 +620,8 @@ err:
                 * we're in journal error state:
                 */
 
-               btree_node_lock_type(c, b, SIX_LOCK_intent);
-               btree_node_lock_type(c, b, SIX_LOCK_write);
+               six_lock_intent(&b->c.lock, NULL, NULL);
+               six_lock_write(&b->c.lock, NULL, NULL);
                mutex_lock(&c->btree_interior_update_lock);
 
                list_del(&as->write_blocked_list);
@@ -660,7 +675,7 @@ err:
        for (i = 0; i < as->nr_new_nodes; i++) {
                b = as->new_nodes[i];
 
-               btree_node_lock_type(c, b, SIX_LOCK_read);
+               six_lock_read(&b->c.lock, NULL, NULL);
                btree_node_write_if_need(c, b, SIX_LOCK_read);
                six_unlock_read(&b->c.lock);
        }
@@ -773,7 +788,7 @@ static void btree_update_updated_root(struct btree_update *as, struct btree *b)
  * And it adds @b to the list of @as's new nodes, so that we can update sector
  * counts in bch2_btree_update_nodes_written:
  */
-void bch2_btree_update_add_new_node(struct btree_update *as, struct btree *b)
+static void bch2_btree_update_add_new_node(struct btree_update *as, struct btree *b)
 {
        struct bch_fs *c = as->c;
 
@@ -827,7 +842,7 @@ found:
                closure_put(&as->cl);
 }
 
-void bch2_btree_update_get_open_buckets(struct btree_update *as, struct btree *b)
+static void bch2_btree_update_get_open_buckets(struct btree_update *as, struct btree *b)
 {
        while (b->ob.nr)
                as->open_buckets[as->nr_open_buckets++] =
@@ -839,7 +854,7 @@ void bch2_btree_update_get_open_buckets(struct btree_update *as, struct btree *b
  * nodes and thus outstanding btree_updates - redirect @b's
  * btree_updates to point to this btree_update:
  */
-void bch2_btree_interior_update_will_free_node(struct btree_update *as,
+static void bch2_btree_interior_update_will_free_node(struct btree_update *as,
                                               struct btree *b)
 {
        struct bch_fs *c = as->c;
@@ -911,8 +926,11 @@ void bch2_btree_interior_update_will_free_node(struct btree_update *as,
        as->nr_old_nodes++;
 }
 
-void bch2_btree_update_done(struct btree_update *as)
+static void bch2_btree_update_done(struct btree_update *as)
 {
+       struct bch_fs *c = as->c;
+       u64 start_time = as->start_time;
+
        BUG_ON(as->mode == BTREE_INTERIOR_NO_UPDATE);
 
        if (as->took_gc_lock)
@@ -923,38 +941,39 @@ void bch2_btree_update_done(struct btree_update *as)
 
        continue_at(&as->cl, btree_update_set_nodes_written,
                    as->c->btree_interior_update_worker);
+
+       bch2_time_stats_update(&c->times[BCH_TIME_btree_interior_update_foreground],
+                              start_time);
 }
 
-struct btree_update *
-bch2_btree_update_start(struct btree_iter *iter, unsigned level,
-                       unsigned nr_nodes, unsigned flags)
+static struct btree_update *
+bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
+                       unsigned level, unsigned nr_nodes, unsigned flags)
 {
-       struct btree_trans *trans = iter->trans;
        struct bch_fs *c = trans->c;
        struct btree_update *as;
-       struct closure cl;
+       u64 start_time = local_clock();
        int disk_res_flags = (flags & BTREE_INSERT_NOFAIL)
                ? BCH_DISK_RESERVATION_NOFAIL : 0;
        int journal_flags = 0;
        int ret = 0;
 
-       BUG_ON(!iter->should_be_locked);
+       BUG_ON(!path->should_be_locked);
 
        if (flags & BTREE_INSERT_JOURNAL_RESERVED)
                journal_flags |= JOURNAL_RES_GET_RESERVED;
-
-       closure_init_stack(&cl);
-retry:
+       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_iter_upgrade(iter, U8_MAX)) {
-               trace_trans_restart_iter_upgrade(trans->ip, _RET_IP_,
-                                                iter->btree_id,
-                                                &iter->real_pos);
-               return ERR_PTR(-EINTR);
+       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);
        }
 
        if (flags & BTREE_INSERT_GC_LOCK_HELD)
@@ -972,9 +991,10 @@ retry:
        memset(as, 0, sizeof(*as));
        closure_init(&as->cl, NULL);
        as->c           = c;
+       as->start_time  = start_time;
        as->mode        = BTREE_INTERIOR_NO_UPDATE;
        as->took_gc_lock = !(flags & BTREE_INSERT_GC_LOCK_HELD);
-       as->btree_id    = iter->btree_id;
+       as->btree_id    = path->btree_id;
        INIT_LIST_HEAD(&as->list);
        INIT_LIST_HEAD(&as->unwritten_list);
        INIT_LIST_HEAD(&as->write_blocked_list);
@@ -998,43 +1018,34 @@ retry:
        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_RES_GET_NONBLOCK);
-       if (ret == -EAGAIN) {
-               bch2_trans_unlock(trans);
-
-               if (flags & BTREE_INSERT_JOURNAL_RECLAIM) {
-                       bch2_btree_update_free(as);
-                       btree_trans_restart(trans);
-                       return ERR_PTR(ret);
-               }
-
-               ret = bch2_journal_preres_get(&c->journal, &as->journal_preres,
-                               BTREE_UPDATE_JOURNAL_RES,
-                               journal_flags);
-               if (ret) {
-                       trace_trans_restart_journal_preres_get(trans->ip, _RET_IP_);
-                       goto err;
-               }
-
-               if (!bch2_trans_relock(trans)) {
-                       ret = -EINTR;
-                       goto err;
-               }
+                                     journal_flags);
+       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);
        }
 
        ret = bch2_disk_reservation_get(c, &as->disk_res,
-                       nr_nodes * c->opts.btree_node_size,
+                       nr_nodes * btree_sectors(c),
                        c->opts.metadata_replicas,
                        disk_res_flags);
        if (ret)
                goto err;
 
-       ret = bch2_btree_reserve_get(as, nr_nodes, flags, &cl);
+       ret = bch2_btree_reserve_get(as, nr_nodes, flags);
        if (ret)
                goto err;
 
+       if (!bch2_trans_relock(trans)) {
+               ret = -EINTR;
+               goto err;
+       }
+
        bch2_journal_pin_add(&c->journal,
                             atomic64_read(&c->journal.seq),
                             &as->journal, NULL);
@@ -1042,16 +1053,6 @@ retry:
        return as;
 err:
        bch2_btree_update_free(as);
-
-       if (ret == -EAGAIN) {
-               bch2_trans_unlock(trans);
-               closure_sync(&cl);
-               ret = -EINTR;
-       }
-
-       if (ret == -EINTR && bch2_trans_relock(trans))
-               goto retry;
-
        return ERR_PTR(ret);
 }
 
@@ -1092,8 +1093,10 @@ static void bch2_btree_set_root_inmem(struct bch_fs *c, struct btree *b)
  * is nothing new to be done.  This just guarantees that there is a
  * journal write.
  */
-static void bch2_btree_set_root(struct btree_update *as, struct btree *b,
-                               struct btree_iter *iter)
+static void bch2_btree_set_root(struct btree_update *as,
+                               struct btree_trans *trans,
+                               struct btree_path *path,
+                               struct btree *b)
 {
        struct bch_fs *c = as->c;
        struct btree *old;
@@ -1108,7 +1111,7 @@ static void bch2_btree_set_root(struct btree_update *as, struct btree *b,
         * Ensure no one is using the old root while we switch to the
         * new root:
         */
-       bch2_btree_node_lock_write(old, iter);
+       bch2_btree_node_lock_write(trans, path, old);
 
        bch2_btree_set_root_inmem(c, b);
 
@@ -1121,15 +1124,17 @@ static void bch2_btree_set_root(struct btree_update *as, struct btree *b,
         * an intent lock on the new root, and any updates that would
         * depend on the new root would have to update the new root.
         */
-       bch2_btree_node_unlock_write(old, iter);
+       bch2_btree_node_unlock_write(trans, path, old);
 }
 
 /* Interior node updates: */
 
-static void bch2_insert_fixup_btree_ptr(struct btree_update *as, struct btree *b,
-                                       struct btree_iter *iter,
-                                       struct bkey_i *insert,
-                                       struct btree_node_iter *node_iter)
+static void bch2_insert_fixup_btree_ptr(struct btree_update *as,
+                                       struct btree_trans *trans,
+                                       struct btree_path *path,
+                                       struct btree *b,
+                                       struct btree_node_iter *node_iter,
+                                       struct bkey_i *insert)
 {
        struct bch_fs *c = as->c;
        struct bkey_packed *k;
@@ -1138,6 +1143,9 @@ static void bch2_insert_fixup_btree_ptr(struct btree_update *as, struct btree *b
        BUG_ON(insert->k.type == KEY_TYPE_btree_ptr_v2 &&
               !btree_ptr_sectors_written(insert));
 
+       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) {
@@ -1161,15 +1169,18 @@ static void bch2_insert_fixup_btree_ptr(struct btree_update *as, struct btree *b
               bkey_iter_pos_cmp(b, k, &insert->k.p) < 0)
                bch2_btree_node_iter_advance(node_iter, b);
 
-       bch2_btree_bset_insert_key(iter, b, node_iter, insert);
+       bch2_btree_bset_insert_key(trans, path, b, node_iter, insert);
        set_btree_node_dirty(c, b);
        set_btree_node_need_write(b);
 }
 
 static void
-__bch2_btree_insert_keys_interior(struct btree_update *as, struct btree *b,
-                                 struct btree_iter *iter, struct keylist *keys,
-                                 struct btree_node_iter node_iter)
+__bch2_btree_insert_keys_interior(struct btree_update *as,
+                                 struct btree_trans *trans,
+                                 struct btree_path *path,
+                                 struct btree *b,
+                                 struct btree_node_iter node_iter,
+                                 struct keylist *keys)
 {
        struct bkey_i *insert = bch2_keylist_front(keys);
        struct bkey_packed *k;
@@ -1181,8 +1192,8 @@ __bch2_btree_insert_keys_interior(struct btree_update *as, struct btree *b,
                ;
 
        while (!bch2_keylist_empty(keys)) {
-               bch2_insert_fixup_btree_ptr(as, b, iter,
-                               bch2_keylist_front(keys), &node_iter);
+               bch2_insert_fixup_btree_ptr(as, trans, path, b,
+                               &node_iter, bch2_keylist_front(keys));
                bch2_keylist_pop_front(keys);
        }
 }
@@ -1192,8 +1203,7 @@ __bch2_btree_insert_keys_interior(struct btree_update *as, struct btree *b,
  * node)
  */
 static struct btree *__btree_split_node(struct btree_update *as,
-                                       struct btree *n1,
-                                       struct btree_iter *iter)
+                                       struct btree *n1)
 {
        struct bkey_format_state s;
        size_t nr_packed = 0, nr_unpacked = 0;
@@ -1308,8 +1318,10 @@ static struct btree *__btree_split_node(struct btree_update *as,
  * nodes that were coalesced, and thus in the middle of a child node post
  * coalescing:
  */
-static void btree_split_insert_keys(struct btree_update *as, struct btree *b,
-                                   struct btree_iter *iter,
+static void btree_split_insert_keys(struct btree_update *as,
+                                   struct btree_trans *trans,
+                                   struct btree_path *path,
+                                   struct btree *b,
                                    struct keylist *keys)
 {
        struct btree_node_iter node_iter;
@@ -1319,7 +1331,7 @@ static void btree_split_insert_keys(struct btree_update *as, struct btree *b,
 
        bch2_btree_node_iter_init(&node_iter, b, &k->k.p);
 
-       __bch2_btree_insert_keys_interior(as, b, iter, keys, node_iter);
+       __bch2_btree_insert_keys_interior(as, trans, path, b, node_iter, keys);
 
        /*
         * We can't tolerate whiteouts here - with whiteouts there can be
@@ -1349,18 +1361,17 @@ static void btree_split_insert_keys(struct btree_update *as, struct btree *b,
        btree_node_interior_verify(as->c, b);
 }
 
-static void btree_split(struct btree_update *as,
-                       struct btree_trans *trans, struct btree_iter *iter,
-                       struct btree *b, struct keylist *keys,
-                       unsigned flags)
+static void 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(iter, b);
+       struct btree *parent = btree_node_parent(path, b);
        struct btree *n1, *n2 = NULL, *n3 = NULL;
        u64 start_time = local_clock();
 
        BUG_ON(!parent && (b != btree_node_root(c, b)));
-       BUG_ON(!btree_node_intent_locked(iter, btree_node_root(c, b)->c.level));
+       BUG_ON(!btree_node_intent_locked(path, btree_node_root(c, b)->c.level));
 
        bch2_btree_interior_update_will_free_node(as, b);
 
@@ -1368,12 +1379,12 @@ static void btree_split(struct btree_update *as,
        bch2_btree_update_add_new_node(as, n1);
 
        if (keys)
-               btree_split_insert_keys(as, n1, iter, 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);
 
-               n2 = __btree_split_node(as, n1, iter);
+               n2 = __btree_split_node(as, n1);
 
                bch2_btree_build_aux_trees(n2);
                bch2_btree_build_aux_trees(n1);
@@ -1398,7 +1409,7 @@ static void btree_split(struct btree_update *as,
                        n3->sib_u64s[0] = U16_MAX;
                        n3->sib_u64s[1] = U16_MAX;
 
-                       btree_split_insert_keys(as, n3, iter, &as->parent_keys);
+                       btree_split_insert_keys(as, trans, path, n3, &as->parent_keys);
 
                        bch2_btree_node_write(c, n3, SIX_LOCK_intent);
                }
@@ -1418,12 +1429,12 @@ static void btree_split(struct btree_update *as,
 
        if (parent) {
                /* Split a non root node */
-               bch2_btree_insert_node(as, trans, iter, parent, &as->parent_keys, flags);
+               bch2_btree_insert_node(as, trans, path, parent, &as->parent_keys, flags);
        } else if (n3) {
-               bch2_btree_set_root(as, n3, iter);
+               bch2_btree_set_root(as, trans, path, n3);
        } else {
                /* Root filled up but didn't need to be split */
-               bch2_btree_set_root(as, n1, iter);
+               bch2_btree_set_root(as, trans, path, n1);
        }
 
        bch2_btree_update_get_open_buckets(as, n1);
@@ -1432,15 +1443,14 @@ static void btree_split(struct btree_update *as,
        if (n3)
                bch2_btree_update_get_open_buckets(as, n3);
 
-       /* Successful split, update the iterator to point to the new nodes: */
+       /* Successful split, update the path to point to the new nodes: */
 
        six_lock_increment(&b->c.lock, SIX_LOCK_intent);
-       bch2_btree_iter_node_drop(iter, b);
        if (n3)
-               bch2_btree_iter_node_replace(iter, n3);
+               bch2_trans_node_add(trans, n3);
        if (n2)
-               bch2_btree_iter_node_replace(iter, n2);
-       bch2_btree_iter_node_replace(iter, n1);
+               bch2_trans_node_add(trans, n2);
+       bch2_trans_node_add(trans, n1);
 
        /*
         * The old node must be freed (in memory) _before_ unlocking the new
@@ -1448,7 +1458,7 @@ static void btree_split(struct btree_update *as,
         * node after another thread has locked and updated the new node, thus
         * seeing stale data:
         */
-       bch2_btree_node_free_inmem(c, b, iter);
+       bch2_btree_node_free_inmem(trans, b);
 
        if (n3)
                six_unlock_intent(&n3->c.lock);
@@ -1456,26 +1466,32 @@ static void btree_split(struct btree_update *as,
                six_unlock_intent(&n2->c.lock);
        six_unlock_intent(&n1->c.lock);
 
-       bch2_btree_trans_verify_locks(trans);
+       bch2_trans_verify_locks(trans);
 
-       bch2_time_stats_update(&c->times[BCH_TIME_btree_node_split],
+       bch2_time_stats_update(&c->times[n2
+                              ? BCH_TIME_btree_node_split
+                              : BCH_TIME_btree_node_compact],
                               start_time);
 }
 
 static void
-bch2_btree_insert_keys_interior(struct btree_update *as, struct btree *b,
-                               struct btree_iter *iter, struct keylist *keys)
+bch2_btree_insert_keys_interior(struct btree_update *as,
+                               struct btree_trans *trans,
+                               struct btree_path *path,
+                               struct btree *b,
+                               struct keylist *keys)
 {
-       struct btree_iter *linked;
+       struct btree_path *linked;
 
-       __bch2_btree_insert_keys_interior(as, b, iter, keys, iter->l[b->c.level].iter);
+       __bch2_btree_insert_keys_interior(as, trans, path, b,
+                                         path->l[b->c.level].iter, keys);
 
        btree_update_updated_node(as, b);
 
-       trans_for_each_iter_with_node(iter->trans, b, linked)
+       trans_for_each_path_with_node(trans, b, linked)
                bch2_btree_node_iter_peek(&linked->l[b->c.level].iter, b);
 
-       bch2_btree_trans_verify_iters(iter->trans, b);
+       bch2_trans_verify_paths(trans);
 }
 
 /**
@@ -1490,10 +1506,9 @@ bch2_btree_insert_keys_interior(struct btree_update *as, struct btree *b,
  * 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_iter *iter,
-                                  struct btree *b, struct keylist *keys,
-                                  unsigned flags)
+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)
 {
        struct bch_fs *c = as->c;
        int old_u64s = le16_to_cpu(btree_bset_last(b)->u64s);
@@ -1501,21 +1516,21 @@ static void bch2_btree_insert_node(struct btree_update *as,
        int live_u64s_added, u64s_added;
 
        lockdep_assert_held(&c->gc_lock);
-       BUG_ON(!btree_node_intent_locked(iter, btree_node_root(c, b)->c.level));
+       BUG_ON(!btree_node_intent_locked(path, btree_node_root(c, 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, iter, b);
+       bch2_btree_node_lock_for_insert(trans, path, b);
 
        if (!bch2_btree_node_insert_fits(c, b, bch2_keylist_u64s(keys))) {
-               bch2_btree_node_unlock_write(b, iter);
+               bch2_btree_node_unlock_write(trans, path, b);
                goto split;
        }
 
        btree_node_interior_verify(c, b);
 
-       bch2_btree_insert_keys_interior(as, b, iter, keys);
+       bch2_btree_insert_keys_interior(as, trans, path, b, keys);
 
        live_u64s_added = (int) b->nr.live_u64s - old_live_u64s;
        u64s_added = (int) le16_to_cpu(btree_bset_last(b)->u64s) - old_u64s;
@@ -1527,48 +1542,48 @@ static void bch2_btree_insert_node(struct btree_update *as,
 
        if (u64s_added > live_u64s_added &&
            bch2_maybe_compact_whiteouts(c, b))
-               bch2_btree_iter_reinit_node(iter, b);
+               bch2_trans_node_reinit_iter(trans, b);
 
-       bch2_btree_node_unlock_write(b, iter);
+       bch2_btree_node_unlock_write(trans, path, b);
 
        btree_node_interior_verify(c, b);
        return;
 split:
-       btree_split(as, trans, iter, b, keys, flags);
+       btree_split(as, trans, path, b, keys, flags);
 }
 
 int bch2_btree_split_leaf(struct btree_trans *trans,
-                         struct btree_iter *iter,
+                         struct btree_path *path,
                          unsigned flags)
 {
        struct bch_fs *c = trans->c;
-       struct btree *b = iter_l(iter)->b;
+       struct btree *b = path_l(path)->b;
        struct btree_update *as;
        unsigned l;
        int ret = 0;
 
-       as = bch2_btree_update_start(iter, iter->level,
+       as = bch2_btree_update_start(trans, path, path->level,
                btree_update_reserve_required(c, b), flags);
        if (IS_ERR(as))
                return PTR_ERR(as);
 
-       btree_split(as, trans, iter, b, NULL, flags);
+       btree_split(as, trans, path, b, NULL, flags);
        bch2_btree_update_done(as);
 
-       for (l = iter->level + 1; btree_iter_node(iter, l) && !ret; l++)
-               ret = bch2_foreground_maybe_merge(trans, iter, l, flags);
+       for (l = path->level + 1; btree_path_node(path, l) && !ret; l++)
+               ret = bch2_foreground_maybe_merge(trans, path, l, flags);
 
        return ret;
 }
 
 int __bch2_foreground_maybe_merge(struct btree_trans *trans,
-                                 struct btree_iter *iter,
+                                 struct btree_path *path,
                                  unsigned level,
                                  unsigned flags,
                                  enum btree_node_sibling sib)
 {
        struct bch_fs *c = trans->c;
-       struct btree_iter *sib_iter = NULL;
+       struct btree_path *sib_path = NULL;
        struct btree_update *as;
        struct bkey_format_state new_s;
        struct bkey_format new_f;
@@ -1576,39 +1591,36 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
        struct btree *b, *m, *n, *prev, *next, *parent;
        struct bpos sib_pos;
        size_t sib_u64s;
-       int ret = 0, ret2 = 0;
-
-retry:
-       ret = bch2_btree_iter_traverse(iter);
-       if (ret)
-               return ret;
+       u64 start_time = local_clock();
+       int ret = 0;
 
-       BUG_ON(!iter->should_be_locked);
-       BUG_ON(!btree_node_locked(iter, level));
+       BUG_ON(!path->should_be_locked);
+       BUG_ON(!btree_node_locked(path, level));
 
-       b = iter->l[level].b;
+       b = path->l[level].b;
 
        if ((sib == btree_prev_sib && !bpos_cmp(b->data->min_key, POS_MIN)) ||
            (sib == btree_next_sib && !bpos_cmp(b->data->max_key, SPOS_MAX))) {
                b->sib_u64s[sib] = U16_MAX;
-               goto out;
+               return 0;
        }
 
        sib_pos = sib == btree_prev_sib
                ? bpos_predecessor(b->data->min_key)
                : bpos_successor(b->data->max_key);
 
-       sib_iter = bch2_trans_get_node_iter(trans, iter->btree_id,
-                                           sib_pos, U8_MAX, level,
-                                           BTREE_ITER_INTENT);
-       ret = bch2_btree_iter_traverse(sib_iter);
+       sib_path = bch2_path_get(trans, path->btree_id, sib_pos,
+                                U8_MAX, level, BTREE_ITER_INTENT, _THIS_IP_);
+       ret = bch2_btree_path_traverse(trans, sib_path, false);
        if (ret)
                goto err;
 
-       m = sib_iter->l[level].b;
+       sib_path->should_be_locked = true;
 
-       if (btree_node_parent(iter, b) !=
-           btree_node_parent(sib_iter, m)) {
+       m = sib_path->l[level].b;
+
+       if (btree_node_parent(path, b) !=
+           btree_node_parent(sib_path, m)) {
                b->sib_u64s[sib] = U16_MAX;
                goto out;
        }
@@ -1659,8 +1671,8 @@ retry:
        if (b->sib_u64s[sib] > c->btree_foreground_merge_threshold)
                goto out;
 
-       parent = btree_node_parent(iter, b);
-       as = bch2_btree_update_start(iter, level,
+       parent = btree_node_parent(path, b);
+       as = bch2_btree_update_start(trans, path, level,
                         btree_update_reserve_required(c, parent) + 1,
                         flags|
                         BTREE_INSERT_NOFAIL|
@@ -1696,47 +1708,34 @@ retry:
        bch2_keylist_add(&as->parent_keys, &delete);
        bch2_keylist_add(&as->parent_keys, &n->key);
 
-       bch2_btree_insert_node(as, trans, iter, parent, &as->parent_keys, flags);
+       bch2_trans_verify_paths(trans);
+
+       bch2_btree_insert_node(as, trans, path, parent, &as->parent_keys, flags);
+
+       bch2_trans_verify_paths(trans);
 
        bch2_btree_update_get_open_buckets(as, n);
 
        six_lock_increment(&b->c.lock, SIX_LOCK_intent);
        six_lock_increment(&m->c.lock, SIX_LOCK_intent);
-       bch2_btree_iter_node_drop(iter, b);
-       bch2_btree_iter_node_drop(iter, m);
 
-       bch2_btree_iter_node_replace(iter, n);
+       bch2_trans_node_add(trans, n);
 
-       bch2_btree_trans_verify_iters(trans, n);
+       bch2_trans_verify_paths(trans);
 
-       bch2_btree_node_free_inmem(c, b, iter);
-       bch2_btree_node_free_inmem(c, m, iter);
+       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);
-out:
-       bch2_btree_trans_verify_locks(trans);
-       bch2_trans_iter_free(trans, sib_iter);
 
-       /*
-        * Don't downgrade locks here: we're called after successful insert,
-        * and the caller will downgrade locks after a successful insert
-        * anyways (in case e.g. a split was required first)
-        *
-        * And we're also called when inserting into interior nodes in the
-        * split path, and downgrading to read locks in there is potentially
-        * confusing:
-        */
-       return ret ?: ret2;
+       bch2_time_stats_update(&c->times[BCH_TIME_btree_node_merge], start_time);
+out:
 err:
-       bch2_trans_iter_put(trans, sib_iter);
-       sib_iter = NULL;
-
-       if (ret == -EINTR && bch2_trans_relock(trans))
-               goto retry;
-
-       goto out;
+       bch2_path_put(trans, sib_path, true);
+       bch2_trans_verify_locks(trans);
+       return ret;
 }
 
 /**
@@ -1744,32 +1743,23 @@ err:
  */
 int bch2_btree_node_rewrite(struct btree_trans *trans,
                            struct btree_iter *iter,
-                           __le64 seq, unsigned flags)
+                           struct btree *b,
+                           unsigned flags)
 {
        struct bch_fs *c = trans->c;
-       struct btree *b, *n, *parent;
+       struct btree *n, *parent;
        struct btree_update *as;
        int ret;
 
        flags |= BTREE_INSERT_NOFAIL;
-retry:
-       ret = bch2_btree_iter_traverse(iter);
-       if (ret)
-               goto out;
 
-       b = bch2_btree_iter_peek_node(iter);
-       if (!b || b->data->keys.seq != seq)
-               goto out;
-
-       parent = btree_node_parent(iter, b);
-       as = bch2_btree_update_start(iter, b->c.level,
+       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);
        ret = PTR_ERR_OR_ZERO(as);
-       if (ret == -EINTR)
-               goto retry;
        if (ret) {
                trace_btree_gc_rewrite_node_fail(c, b);
                goto out;
@@ -1789,23 +1779,22 @@ retry:
 
        if (parent) {
                bch2_keylist_add(&as->parent_keys, &n->key);
-               bch2_btree_insert_node(as, trans, iter, parent,
+               bch2_btree_insert_node(as, trans, iter->path, parent,
                                       &as->parent_keys, flags);
        } else {
-               bch2_btree_set_root(as, n, iter);
+               bch2_btree_set_root(as, trans, iter->path, n);
        }
 
        bch2_btree_update_get_open_buckets(as, n);
 
        six_lock_increment(&b->c.lock, SIX_LOCK_intent);
-       bch2_btree_iter_node_drop(iter, b);
-       bch2_btree_iter_node_replace(iter, n);
-       bch2_btree_node_free_inmem(c, b, iter);
+       bch2_trans_node_add(trans, n);
+       bch2_btree_node_free_inmem(trans, b);
        six_unlock_intent(&n->c.lock);
 
        bch2_btree_update_done(as);
 out:
-       bch2_btree_iter_downgrade(iter);
+       bch2_btree_path_downgrade(iter->path);
        return ret;
 }
 
@@ -1818,20 +1807,38 @@ struct async_btree_rewrite {
        __le64                  seq;
 };
 
+static int async_btree_node_rewrite_trans(struct btree_trans *trans,
+                                         struct async_btree_rewrite *a)
+{
+       struct btree_iter iter;
+       struct btree *b;
+       int ret;
+
+       bch2_trans_node_iter_init(trans, &iter, a->btree_id, a->pos,
+                                 BTREE_MAX_DEPTH, a->level, 0);
+       b = bch2_btree_iter_peek_node(&iter);
+       ret = PTR_ERR_OR_ZERO(b);
+       if (ret)
+               goto out;
+
+       if (!b || b->data->keys.seq != a->seq)
+               goto out;
+
+       ret = bch2_btree_node_rewrite(trans, &iter, b, 0);
+out :
+       bch2_trans_iter_exit(trans, &iter);
+
+       return ret;
+}
+
 void async_btree_node_rewrite_work(struct work_struct *work)
 {
        struct async_btree_rewrite *a =
                container_of(work, struct async_btree_rewrite, work);
        struct bch_fs *c = a->c;
-       struct btree_trans trans;
-       struct btree_iter *iter;
 
-       bch2_trans_init(&trans, c, 0, 0);
-       iter = bch2_trans_get_node_iter(&trans, a->btree_id, a->pos,
-                                       BTREE_MAX_DEPTH, a->level, 0);
-       bch2_btree_node_rewrite(&trans, iter, a->seq, 0);
-       bch2_trans_iter_put(&trans, iter);
-       bch2_trans_exit(&trans);
+       bch2_trans_do(c, NULL, NULL, 0,
+                     async_btree_node_rewrite_trans(&trans, a));
        percpu_ref_put(&c->writes);
        kfree(a);
 }
@@ -1840,9 +1847,6 @@ void bch2_btree_node_rewrite_async(struct bch_fs *c, struct btree *b)
 {
        struct async_btree_rewrite *a;
 
-       if (!test_bit(BCH_FS_BTREE_INTERIOR_REPLAY_DONE, &c->flags))
-               return;
-
        if (!percpu_ref_tryget(&c->writes))
                return;
 
@@ -1869,7 +1873,7 @@ static int __bch2_btree_node_update_key(struct btree_trans *trans,
                                        bool skip_triggers)
 {
        struct bch_fs *c = trans->c;
-       struct btree_iter *iter2 = NULL;
+       struct btree_iter iter2 = { NULL };
        struct btree *parent;
        u64 journal_entries[BKEY_BTREE_PTR_U64s_MAX];
        int ret;
@@ -1897,19 +1901,23 @@ static int __bch2_btree_node_update_key(struct btree_trans *trans,
                BUG_ON(ret);
        }
 
-       parent = btree_node_parent(iter, b);
+       parent = btree_node_parent(iter->path, b);
        if (parent) {
-               iter2 = bch2_trans_copy_iter(trans, iter);
+               bch2_trans_copy_iter(&iter2, iter);
 
-               BUG_ON(iter2->level != b->c.level);
-               BUG_ON(bpos_cmp(iter2->pos, new_key->k.p));
+               iter2.path = bch2_btree_path_make_mut(trans, iter2.path,
+                               iter2.flags & BTREE_ITER_INTENT,
+                               _THIS_IP_);
 
-               btree_node_unlock(iter2, iter2->level);
-               iter2->l[iter2->level].b = BTREE_ITER_NO_NODE_UP;
-               iter2->level++;
+               BUG_ON(iter2.path->level != b->c.level);
+               BUG_ON(bpos_cmp(iter2.path->pos, new_key->k.p));
 
-               ret   = bch2_btree_iter_traverse(iter2) ?:
-                       bch2_trans_update(trans, iter2, new_key, BTREE_TRIGGER_NORUN);
+               btree_node_unlock(iter2.path, iter2.path->level);
+               path_l(iter2.path)->b = BTREE_ITER_NO_NODE_UP;
+               iter2.path->level++;
+
+               ret   = bch2_btree_iter_traverse(&iter2) ?:
+                       bch2_trans_update(trans, &iter2, new_key, BTREE_TRIGGER_NORUN);
                if (ret)
                        goto err;
        } else {
@@ -1926,12 +1934,13 @@ static int __bch2_btree_node_update_key(struct btree_trans *trans,
        ret = bch2_trans_commit(trans, NULL, NULL,
                                BTREE_INSERT_NOFAIL|
                                BTREE_INSERT_NOCHECK_RW|
+                               BTREE_INSERT_USE_RESERVE|
                                BTREE_INSERT_JOURNAL_RECLAIM|
                                BTREE_INSERT_JOURNAL_RESERVED);
        if (ret)
                goto err;
 
-       bch2_btree_node_lock_write(b, iter);
+       bch2_btree_node_lock_write(trans, iter->path, b);
 
        if (new_hash) {
                mutex_lock(&c->btree_cache.lock);
@@ -1946,9 +1955,9 @@ static int __bch2_btree_node_update_key(struct btree_trans *trans,
                bkey_copy(&b->key, new_key);
        }
 
-       bch2_btree_node_unlock_write(b, iter);
+       bch2_btree_node_unlock_write(trans, iter->path, b);
 out:
-       bch2_trans_iter_put(trans, iter2);
+       bch2_trans_iter_exit(trans, &iter2);
        return ret;
 err:
        if (new_hash) {
@@ -1965,9 +1974,16 @@ int bch2_btree_node_update_key(struct btree_trans *trans, struct btree_iter *ite
 {
        struct bch_fs *c = trans->c;
        struct btree *new_hash = NULL;
+       struct btree_path *path = iter->path;
        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;
+       }
+
        closure_init_stack(&cl);
 
        /*
@@ -1986,8 +2002,10 @@ int bch2_btree_node_update_key(struct btree_trans *trans, struct btree_iter *ite
                new_hash = bch2_btree_node_mem_alloc(c);
        }
 
+       path->intent_ref++;
        ret = __bch2_btree_node_update_key(trans, iter, b, new_hash,
                                           new_key, skip_triggers);
+       --path->intent_ref;
 
        if (new_hash) {
                mutex_lock(&c->btree_cache.lock);
@@ -2006,18 +2024,18 @@ int bch2_btree_node_update_key_get_iter(struct btree_trans *trans,
                                        struct btree *b, struct bkey_i *new_key,
                                        bool skip_triggers)
 {
-       struct btree_iter *iter;
+       struct btree_iter iter;
        int ret;
 
-       iter = bch2_trans_get_node_iter(trans, b->c.btree_id, b->key.k.p,
-                                       BTREE_MAX_DEPTH, b->c.level,
-                                       BTREE_ITER_INTENT);
-       ret = bch2_btree_iter_traverse(iter);
+       bch2_trans_node_iter_init(trans, &iter, b->c.btree_id, b->key.k.p,
+                                 BTREE_MAX_DEPTH, b->c.level,
+                                 BTREE_ITER_INTENT);
+       ret = bch2_btree_iter_traverse(&iter);
        if (ret)
                goto out;
 
        /* has node been freed? */
-       if (iter->l[b->c.level].b != b) {
+       if (iter.path->l[b->c.level].b != b) {
                /* node has been freed: */
                BUG_ON(!btree_node_dying(b));
                goto out;
@@ -2025,9 +2043,9 @@ int bch2_btree_node_update_key_get_iter(struct btree_trans *trans,
 
        BUG_ON(!btree_node_hashed(b));
 
-       ret = bch2_btree_node_update_key(trans, iter, b, new_key, skip_triggers);
+       ret = bch2_btree_node_update_key(trans, &iter, b, new_key, skip_triggers);
 out:
-       bch2_trans_iter_put(trans, iter);
+       bch2_trans_iter_exit(trans, &iter);
        return ret;
 }