]> git.sesse.net Git - bcachefs-tools-debian/blobdiff - libbcachefs/btree_gc.c
Update bcachefs sources to 24c6361e20 bcachefs: Fix a trans path overflow in bch2_btr...
[bcachefs-tools-debian] / libbcachefs / btree_gc.c
index 9556b05312859672407b67973bbf2b486da62f95..5b7f7cd3252a6db4a68089b275a07633645aea9b 100644 (file)
@@ -98,7 +98,7 @@ static int bch2_gc_check_topology(struct bch_fs *c,
                                  buf1.buf, buf2.buf) &&
                            !test_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags)) {
                                bch_info(c, "Halting mark and sweep to start topology repair pass");
-                               ret = FSCK_ERR_START_TOPOLOGY_REPAIR;
+                               ret = -BCH_ERR_need_topology_repair;
                                goto err;
                        } else {
                                set_bit(BCH_FS_INITIAL_GC_UNFIXED, &c->flags);
@@ -126,7 +126,7 @@ static int bch2_gc_check_topology(struct bch_fs *c,
                          buf1.buf, buf2.buf) &&
                    !test_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags)) {
                        bch_info(c, "Halting mark and sweep to start topology repair pass");
-                       ret = FSCK_ERR_START_TOPOLOGY_REPAIR;
+                       ret = -BCH_ERR_need_topology_repair;
                        goto err;
                } else {
                        set_bit(BCH_FS_INITIAL_GC_UNFIXED, &c->flags);
@@ -165,10 +165,11 @@ static void btree_ptr_to_v2(struct btree *b, struct bkey_i_btree_ptr_v2 *dst)
        }
 }
 
-static void bch2_btree_node_update_key_early(struct bch_fs *c,
+static void bch2_btree_node_update_key_early(struct btree_trans *trans,
                                             enum btree_id btree, unsigned level,
                                             struct bkey_s_c old, struct bkey_i *new)
 {
+       struct bch_fs *c = trans->c;
        struct btree *b;
        struct bkey_buf tmp;
        int ret;
@@ -176,7 +177,7 @@ static void bch2_btree_node_update_key_early(struct bch_fs *c,
        bch2_bkey_buf_init(&tmp);
        bch2_bkey_buf_reassemble(&tmp, c, old);
 
-       b = bch2_btree_node_get_noiter(c, tmp.k, btree, level, true);
+       b = bch2_btree_node_get_noiter(trans, tmp.k, btree, level, true);
        if (!IS_ERR_OR_NULL(b)) {
                mutex_lock(&c->btree_cache.lock);
 
@@ -352,8 +353,9 @@ fsck_err:
        return ret;
 }
 
-static int bch2_btree_repair_topology_recurse(struct bch_fs *c, struct btree *b)
+static int bch2_btree_repair_topology_recurse(struct btree_trans *trans, struct btree *b)
 {
+       struct bch_fs *c = trans->c;
        struct btree_and_journal_iter iter;
        struct bkey_s_c k;
        struct bkey_buf prev_k, cur_k;
@@ -378,7 +380,7 @@ again:
                bch2_btree_and_journal_iter_advance(&iter);
                bch2_bkey_buf_reassemble(&cur_k, c, k);
 
-               cur = bch2_btree_node_get_noiter(c, cur_k.k,
+               cur = bch2_btree_node_get_noiter(trans, cur_k.k,
                                        b->c.btree_id, b->c.level - 1,
                                        false);
                ret = PTR_ERR_OR_ZERO(cur);
@@ -392,7 +394,7 @@ again:
                                bch2_btree_ids[b->c.btree_id],
                                b->c.level - 1,
                                buf.buf)) {
-                       bch2_btree_node_evict(c, cur_k.k);
+                       bch2_btree_node_evict(trans, cur_k.k);
                        ret = bch2_journal_key_delete(c, b->c.btree_id,
                                                      b->c.level, cur_k.k->k.p);
                        cur = NULL;
@@ -402,8 +404,8 @@ again:
                }
 
                if (ret) {
-                       bch_err(c, "%s: error %i getting btree node",
-                               __func__, ret);
+                       bch_err(c, "%s: error getting btree node: %s",
+                               __func__, bch2_err_str(ret));
                        break;
                }
 
@@ -411,7 +413,7 @@ again:
 
                if (ret == DROP_THIS_NODE) {
                        six_unlock_read(&cur->c.lock);
-                       bch2_btree_node_evict(c, cur_k.k);
+                       bch2_btree_node_evict(trans, cur_k.k);
                        ret = bch2_journal_key_delete(c, b->c.btree_id,
                                                      b->c.level, cur_k.k->k.p);
                        cur = NULL;
@@ -425,7 +427,7 @@ again:
                prev = NULL;
 
                if (ret == DROP_PREV_NODE) {
-                       bch2_btree_node_evict(c, prev_k.k);
+                       bch2_btree_node_evict(trans, prev_k.k);
                        ret = bch2_journal_key_delete(c, b->c.btree_id,
                                                      b->c.level, prev_k.k->k.p);
                        if (ret)
@@ -465,23 +467,23 @@ again:
                bch2_bkey_buf_reassemble(&cur_k, c, k);
                bch2_btree_and_journal_iter_advance(&iter);
 
-               cur = bch2_btree_node_get_noiter(c, cur_k.k,
+               cur = bch2_btree_node_get_noiter(trans, cur_k.k,
                                        b->c.btree_id, b->c.level - 1,
                                        false);
                ret = PTR_ERR_OR_ZERO(cur);
 
                if (ret) {
-                       bch_err(c, "%s: error %i getting btree node",
-                               __func__, ret);
+                       bch_err(c, "%s: error getting btree node: %s",
+                               __func__, bch2_err_str(ret));
                        goto err;
                }
 
-               ret = bch2_btree_repair_topology_recurse(c, cur);
+               ret = bch2_btree_repair_topology_recurse(trans, cur);
                six_unlock_read(&cur->c.lock);
                cur = NULL;
 
                if (ret == DROP_THIS_NODE) {
-                       bch2_btree_node_evict(c, cur_k.k);
+                       bch2_btree_node_evict(trans, cur_k.k);
                        ret = bch2_journal_key_delete(c, b->c.btree_id,
                                                      b->c.level, cur_k.k->k.p);
                        dropped_children = true;
@@ -522,32 +524,38 @@ fsck_err:
 
 static int bch2_repair_topology(struct bch_fs *c)
 {
+       struct btree_trans trans;
        struct btree *b;
        unsigned i;
        int ret = 0;
 
+       bch2_trans_init(&trans, c, 0, 0);
+
        for (i = 0; i < BTREE_ID_NR && !ret; i++) {
                b = c->btree_roots[i].b;
                if (btree_node_fake(b))
                        continue;
 
-               six_lock_read(&b->c.lock, NULL, NULL);
-               ret = bch2_btree_repair_topology_recurse(c, b);
+               btree_node_lock_nopath_nofail(&trans, &b->c, SIX_LOCK_read);
+               ret = bch2_btree_repair_topology_recurse(&trans, b);
                six_unlock_read(&b->c.lock);
 
                if (ret == DROP_THIS_NODE) {
                        bch_err(c, "empty btree root - repair unimplemented");
-                       ret = FSCK_ERR_EXIT;
+                       ret = -BCH_ERR_fsck_repair_unimplemented;
                }
        }
 
+       bch2_trans_exit(&trans);
+
        return ret;
 }
 
-static int bch2_check_fix_ptrs(struct bch_fs *c, enum btree_id btree_id,
+static int bch2_check_fix_ptrs(struct btree_trans *trans, enum btree_id btree_id,
                               unsigned level, bool is_root,
                               struct bkey_s_c *k)
 {
+       struct bch_fs *c = trans->c;
        struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(*k);
        const union bch_extent_entry *entry;
        struct extent_ptr_decoded p = { 0 };
@@ -747,7 +755,7 @@ found:
                }
 
                if (level)
-                       bch2_btree_node_update_key_early(c, btree_id, level - 1, *k, new);
+                       bch2_btree_node_update_key_early(trans, btree_id, level - 1, *k, new);
 
                if (c->opts.verbose) {
                        printbuf_reset(&buf);
@@ -788,7 +796,7 @@ static int bch2_gc_mark_key(struct btree_trans *trans, enum btree_id btree_id,
                BUG_ON(bch2_journal_seq_verify &&
                       k->k->version.lo > atomic64_read(&c->journal.seq));
 
-               ret = bch2_check_fix_ptrs(c, btree_id, level, is_root, k);
+               ret = bch2_check_fix_ptrs(trans, btree_id, level, is_root, k);
                if (ret)
                        goto err;
 
@@ -799,12 +807,12 @@ static int bch2_gc_mark_key(struct btree_trans *trans, enum btree_id btree_id,
                        atomic64_set(&c->key_version, k->k->version.lo);
        }
 
-       ret = __bch2_trans_do(trans, NULL, NULL, 0,
+       ret = commit_do(trans, NULL, NULL, 0,
                        bch2_mark_key(trans, old, *k, flags));
 fsck_err:
 err:
        if (ret)
-               bch_err(c, "%s: ret %i", __func__, ret);
+               bch_err(c, "error from %s(): %s", __func__, bch2_err_str(ret));
        return ret;
 }
 
@@ -910,7 +918,8 @@ static int bch2_gc_btree_init_recurse(struct btree_trans *trans, struct btree *b
                ret = bch2_gc_mark_key(trans, b->c.btree_id, b->c.level,
                                       false, &k, true);
                if (ret) {
-                       bch_err(c, "%s: error %i from bch2_gc_mark_key", __func__, ret);
+                       bch_err(c, "%s: error from bch2_gc_mark_key: %s",
+                               __func__, bch2_err_str(ret));
                        goto fsck_err;
                }
 
@@ -940,7 +949,7 @@ static int bch2_gc_btree_init_recurse(struct btree_trans *trans, struct btree *b
                        bch2_bkey_buf_reassemble(&cur, c, k);
                        bch2_btree_and_journal_iter_advance(&iter);
 
-                       child = bch2_btree_node_get_noiter(c, cur.k,
+                       child = bch2_btree_node_get_noiter(trans, cur.k,
                                                b->c.btree_id, b->c.level - 1,
                                                false);
                        ret = PTR_ERR_OR_ZERO(child);
@@ -959,7 +968,7 @@ static int bch2_gc_btree_init_recurse(struct btree_trans *trans, struct btree *b
                                          (printbuf_reset(&buf),
                                           bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(cur.k)), buf.buf)) &&
                                    !test_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags)) {
-                                       ret = FSCK_ERR_START_TOPOLOGY_REPAIR;
+                                       ret = -BCH_ERR_need_topology_repair;
                                        bch_info(c, "Halting mark and sweep to start topology repair pass");
                                        goto fsck_err;
                                } else {
@@ -970,8 +979,8 @@ static int bch2_gc_btree_init_recurse(struct btree_trans *trans, struct btree *b
                                        continue;
                                }
                        } else if (ret) {
-                               bch_err(c, "%s: error %i getting btree node",
-                                       __func__, ret);
+                               bch_err(c, "%s: error getting btree node: %s",
+                                       __func__, bch2_err_str(ret));
                                break;
                        }
 
@@ -1012,7 +1021,7 @@ static int bch2_gc_btree_init(struct btree_trans *trans,
        if (mustfix_fsck_err_on(bpos_cmp(b->data->min_key, POS_MIN), c,
                        "btree root with incorrect min_key: %s", buf.buf)) {
                bch_err(c, "repair unimplemented");
-               ret = FSCK_ERR_EXIT;
+               ret = -BCH_ERR_fsck_repair_unimplemented;
                goto fsck_err;
        }
 
@@ -1021,7 +1030,7 @@ static int bch2_gc_btree_init(struct btree_trans *trans,
        if (mustfix_fsck_err_on(bpos_cmp(b->data->max_key, SPOS_MAX), c,
                        "btree root with incorrect max_key: %s", buf.buf)) {
                bch_err(c, "repair unimplemented");
-               ret = FSCK_ERR_EXIT;
+               ret = -BCH_ERR_fsck_repair_unimplemented;
                goto fsck_err;
        }
 
@@ -1038,7 +1047,7 @@ fsck_err:
        six_unlock_read(&b->c.lock);
 
        if (ret < 0)
-               bch_err(c, "%s: ret %i", __func__, ret);
+               bch_err(c, "error from %s(): %s", __func__, bch2_err_str(ret));
        printbuf_exit(&buf);
        return ret;
 }
@@ -1071,7 +1080,7 @@ static int bch2_gc_btrees(struct bch_fs *c, bool initial, bool metadata_only)
                        : bch2_gc_btree(&trans, ids[i], initial, metadata_only);
 
        if (ret < 0)
-               bch_err(c, "%s: ret %i", __func__, ret);
+               bch_err(c, "error from %s(): %s", __func__, bch2_err_str(ret));
 
        bch2_trans_exit(&trans);
        return ret;
@@ -1269,7 +1278,7 @@ fsck_err:
        if (ca)
                percpu_ref_put(&ca->ref);
        if (ret)
-               bch_err(c, "%s: ret %i", __func__, ret);
+               bch_err(c, "error from %s(): %s", __func__, bch2_err_str(ret));
 
        percpu_up_write(&c->mark_lock);
        printbuf_exit(&buf);
@@ -1324,21 +1333,19 @@ static inline bool bch2_alloc_v4_cmp(struct bch_alloc_v4 l,
 
 static int bch2_alloc_write_key(struct btree_trans *trans,
                                struct btree_iter *iter,
+                               struct bkey_s_c k,
                                bool metadata_only)
 {
        struct bch_fs *c = trans->c;
        struct bch_dev *ca = bch_dev_bkey_exists(c, iter->pos.inode);
        struct bucket gc, *b;
-       struct bkey_s_c k;
        struct bkey_i_alloc_v4 *a;
        struct bch_alloc_v4 old, new;
        enum bch_data_type type;
        int ret;
 
-       k = bch2_btree_iter_peek_slot(iter);
-       ret = bkey_err(k);
-       if (ret)
-               return ret;
+       if (bkey_cmp(iter->pos, POS(ca->dev_idx, ca->mi.nbuckets)) >= 0)
+               return 1;
 
        bch2_alloc_to_v4(k, &old);
        new = old;
@@ -1431,31 +1438,21 @@ static int bch2_gc_alloc_done(struct bch_fs *c, bool metadata_only)
        bch2_trans_init(&trans, c, 0, 0);
 
        for_each_member_device(ca, c, i) {
-               for_each_btree_key(&trans, iter, BTREE_ID_alloc,
-                                  POS(ca->dev_idx, ca->mi.first_bucket),
-                                  BTREE_ITER_SLOTS|
-                                  BTREE_ITER_PREFETCH, k, ret) {
-                       if (bkey_cmp(iter.pos, POS(ca->dev_idx, ca->mi.nbuckets)) >= 0)
-                               break;
-
-                       ret = __bch2_trans_do(&trans, NULL, NULL,
-                                             BTREE_INSERT_LAZY_RW,
-                                       bch2_alloc_write_key(&trans, &iter,
-                                                            metadata_only));
-                       if (ret)
-                               break;
-               }
-               bch2_trans_iter_exit(&trans, &iter);
-
-               if (ret) {
-                       bch_err(c, "error writing alloc info: %i", ret);
+               ret = for_each_btree_key_commit(&trans, iter, BTREE_ID_alloc,
+                               POS(ca->dev_idx, ca->mi.first_bucket),
+                               BTREE_ITER_SLOTS|BTREE_ITER_PREFETCH, k,
+                               NULL, NULL, BTREE_INSERT_LAZY_RW,
+                       bch2_alloc_write_key(&trans, &iter, k, metadata_only));
+
+               if (ret < 0) {
+                       bch_err(c, "error writing alloc info: %s", bch2_err_str(ret));
                        percpu_ref_put(&ca->ref);
                        break;
                }
        }
 
        bch2_trans_exit(&trans);
-       return ret;
+       return ret < 0 ? ret : 0;
 }
 
 static int bch2_gc_alloc_start(struct bch_fs *c, bool metadata_only)
@@ -1512,7 +1509,7 @@ static int bch2_gc_alloc_start(struct bch_fs *c, bool metadata_only)
        bch2_trans_exit(&trans);
 
        if (ret)
-               bch_err(c, "error reading alloc info at gc start: %i", ret);
+               bch_err(c, "error reading alloc info at gc start: %s", bch2_err_str(ret));
 
        return ret;
 }
@@ -1539,72 +1536,79 @@ static void bch2_gc_alloc_reset(struct bch_fs *c, bool metadata_only)
        };
 }
 
-static int bch2_gc_reflink_done(struct bch_fs *c, bool metadata_only)
+static int bch2_gc_write_reflink_key(struct btree_trans *trans,
+                                    struct btree_iter *iter,
+                                    struct bkey_s_c k,
+                                    size_t *idx)
 {
-       struct btree_trans trans;
-       struct btree_iter iter;
-       struct bkey_s_c k;
-       struct reflink_gc *r;
-       size_t idx = 0;
+       struct bch_fs *c = trans->c;
+       const __le64 *refcount = bkey_refcount_c(k);
        struct printbuf buf = PRINTBUF;
+       struct reflink_gc *r;
        int ret = 0;
 
-       if (metadata_only)
+       if (!refcount)
                return 0;
 
-       bch2_trans_init(&trans, c, 0, 0);
+       while ((r = genradix_ptr(&c->reflink_gc_table, *idx)) &&
+              r->offset < k.k->p.offset)
+               ++*idx;
 
-       for_each_btree_key(&trans, iter, BTREE_ID_reflink, POS_MIN,
-                          BTREE_ITER_PREFETCH, k, ret) {
-               const __le64 *refcount = bkey_refcount_c(k);
+       if (!r ||
+           r->offset != k.k->p.offset ||
+           r->size != k.k->size) {
+               bch_err(c, "unexpected inconsistency walking reflink table at gc finish");
+               return -EINVAL;
+       }
 
-               if (!refcount)
-                       continue;
+       if (fsck_err_on(r->refcount != le64_to_cpu(*refcount), c,
+                       "reflink key has wrong refcount:\n"
+                       "  %s\n"
+                       "  should be %u",
+                       (bch2_bkey_val_to_text(&buf, c, k), buf.buf),
+                       r->refcount)) {
+               struct bkey_i *new;
 
-               r = genradix_ptr(&c->reflink_gc_table, idx++);
-               if (!r ||
-                   r->offset != k.k->p.offset ||
-                   r->size != k.k->size) {
-                       bch_err(c, "unexpected inconsistency walking reflink table at gc finish");
-                       ret = -EINVAL;
-                       break;
-               }
+               new = bch2_trans_kmalloc(trans, bkey_bytes(k.k));
+               ret = PTR_ERR_OR_ZERO(new);
+               if (ret)
+                       return ret;
 
-               if (fsck_err_on(r->refcount != le64_to_cpu(*refcount), c,
-                               "reflink key has wrong refcount:\n"
-                               "  %s\n"
-                               "  should be %u",
-                               (printbuf_reset(&buf),
-                                bch2_bkey_val_to_text(&buf, c, k), buf.buf),
-                               r->refcount)) {
-                       struct bkey_i *new;
+               bkey_reassemble(new, k);
 
-                       new = kmalloc(bkey_bytes(k.k), GFP_KERNEL);
-                       if (!new) {
-                               ret = -ENOMEM;
-                               break;
-                       }
+               if (!r->refcount)
+                       new->k.type = KEY_TYPE_deleted;
+               else
+                       *bkey_refcount(new) = cpu_to_le64(r->refcount);
 
-                       bkey_reassemble(new, k);
+               ret = bch2_trans_update(trans, iter, new, 0);
+       }
+fsck_err:
+       printbuf_exit(&buf);
+       return ret;
+}
 
-                       if (!r->refcount)
-                               new->k.type = KEY_TYPE_deleted;
-                       else
-                               *bkey_refcount(new) = cpu_to_le64(r->refcount);
+static int bch2_gc_reflink_done(struct bch_fs *c, bool metadata_only)
+{
+       struct btree_trans trans;
+       struct btree_iter iter;
+       struct bkey_s_c k;
+       size_t idx = 0;
+       int ret = 0;
 
-                       ret = __bch2_trans_do(&trans, NULL, NULL, 0,
-                               __bch2_btree_insert(&trans, BTREE_ID_reflink, new));
-                       kfree(new);
+       if (metadata_only)
+               return 0;
+
+       bch2_trans_init(&trans, c, 0, 0);
+
+       ret = for_each_btree_key_commit(&trans, iter,
+                       BTREE_ID_reflink, POS_MIN,
+                       BTREE_ITER_PREFETCH, k,
+                       NULL, NULL, BTREE_INSERT_NOFAIL,
+               bch2_gc_write_reflink_key(&trans, &iter, k, &idx));
 
-                       if (ret)
-                               break;
-               }
-       }
-fsck_err:
-       bch2_trans_iter_exit(&trans, &iter);
        c->reflink_gc_nr = 0;
        bch2_trans_exit(&trans);
-       printbuf_exit(&buf);
        return ret;
 }
 
@@ -1656,66 +1660,73 @@ static void bch2_gc_reflink_reset(struct bch_fs *c, bool metadata_only)
                r->refcount = 0;
 }
 
-static int bch2_gc_stripes_done(struct bch_fs *c, bool metadata_only)
+static int bch2_gc_write_stripes_key(struct btree_trans *trans,
+                                    struct btree_iter *iter,
+                                    struct bkey_s_c k)
 {
-       struct btree_trans trans;
-       struct btree_iter iter;
-       struct bkey_s_c k;
-       struct gc_stripe *m;
-       const struct bch_stripe *s;
+       struct bch_fs *c = trans->c;
        struct printbuf buf = PRINTBUF;
+       const struct bch_stripe *s;
+       struct gc_stripe *m;
        unsigned i;
        int ret = 0;
 
-       if (metadata_only)
+       if (k.k->type != KEY_TYPE_stripe)
                return 0;
 
-       bch2_trans_init(&trans, c, 0, 0);
-
-       for_each_btree_key(&trans, iter, BTREE_ID_stripes, POS_MIN,
-                          BTREE_ITER_PREFETCH, k, ret) {
-               if (k.k->type != KEY_TYPE_stripe)
-                       continue;
-
-               s = bkey_s_c_to_stripe(k).v;
-               m = genradix_ptr(&c->gc_stripes, k.k->p.offset);
+       s = bkey_s_c_to_stripe(k).v;
+       m = genradix_ptr(&c->gc_stripes, k.k->p.offset);
 
-               for (i = 0; i < s->nr_blocks; i++)
-                       if (stripe_blockcount_get(s, i) != (m ? m->block_sectors[i] : 0))
-                               goto inconsistent;
-               continue;
+       for (i = 0; i < s->nr_blocks; i++)
+               if (stripe_blockcount_get(s, i) != (m ? m->block_sectors[i] : 0))
+                       goto inconsistent;
+       return 0;
 inconsistent:
-               if (fsck_err_on(true, c,
-                               "stripe has wrong block sector count %u:\n"
-                               "  %s\n"
-                               "  should be %u", i,
-                               (printbuf_reset(&buf),
-                                bch2_bkey_val_to_text(&buf, c, k), buf.buf),
-                               m ? m->block_sectors[i] : 0)) {
-                       struct bkey_i_stripe *new;
-
-                       new = kmalloc(bkey_bytes(k.k), GFP_KERNEL);
-                       if (!new) {
-                               ret = -ENOMEM;
-                               break;
-                       }
+       if (fsck_err_on(true, c,
+                       "stripe has wrong block sector count %u:\n"
+                       "  %s\n"
+                       "  should be %u", i,
+                       (printbuf_reset(&buf),
+                        bch2_bkey_val_to_text(&buf, c, k), buf.buf),
+                       m ? m->block_sectors[i] : 0)) {
+               struct bkey_i_stripe *new;
+
+               new = bch2_trans_kmalloc(trans, bkey_bytes(k.k));
+               ret = PTR_ERR_OR_ZERO(new);
+               if (ret)
+                       return ret;
 
-                       bkey_reassemble(&new->k_i, k);
+               bkey_reassemble(&new->k_i, k);
 
-                       for (i = 0; i < new->v.nr_blocks; i++)
-                               stripe_blockcount_set(&new->v, i, m ? m->block_sectors[i] : 0);
+               for (i = 0; i < new->v.nr_blocks; i++)
+                       stripe_blockcount_set(&new->v, i, m ? m->block_sectors[i] : 0);
 
-                       ret = __bch2_trans_do(&trans, NULL, NULL, 0,
-                               __bch2_btree_insert(&trans, BTREE_ID_reflink, &new->k_i));
-                       kfree(new);
-               }
+               ret = bch2_trans_update(trans, iter, &new->k_i, 0);
        }
 fsck_err:
-       bch2_trans_iter_exit(&trans, &iter);
+       printbuf_exit(&buf);
+       return ret;
+}
 
-       bch2_trans_exit(&trans);
+static int bch2_gc_stripes_done(struct bch_fs *c, bool metadata_only)
+{
+       struct btree_trans trans;
+       struct btree_iter iter;
+       struct bkey_s_c k;
+       int ret = 0;
 
-       printbuf_exit(&buf);
+       if (metadata_only)
+               return 0;
+
+       bch2_trans_init(&trans, c, 0, 0);
+
+       ret = for_each_btree_key_commit(&trans, iter,
+                       BTREE_ID_stripes, POS_MIN,
+                       BTREE_ITER_PREFETCH, k,
+                       NULL, NULL, BTREE_INSERT_NOFAIL,
+               bch2_gc_write_stripes_key(&trans, &iter, k));
+
+       bch2_trans_exit(&trans);
        return ret;
 }
 
@@ -1777,7 +1788,7 @@ again:
 
        ret = bch2_gc_btrees(c, initial, metadata_only);
 
-       if (ret == FSCK_ERR_START_TOPOLOGY_REPAIR &&
+       if (ret == -BCH_ERR_need_topology_repair &&
            !test_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags) &&
            !test_bit(BCH_FS_INITIAL_GC_DONE, &c->flags)) {
                set_bit(BCH_FS_NEED_ANOTHER_GC, &c->flags);
@@ -1785,8 +1796,8 @@ again:
                ret = 0;
        }
 
-       if (ret == FSCK_ERR_START_TOPOLOGY_REPAIR)
-               ret = FSCK_ERR_EXIT;
+       if (ret == -BCH_ERR_need_topology_repair)
+               ret = -BCH_ERR_fsck_errors_not_fixed;
 
        if (ret)
                goto out;
@@ -1848,10 +1859,15 @@ out:
        return ret;
 }
 
-static bool gc_btree_gens_key(struct bch_fs *c, struct bkey_s_c k)
+static int gc_btree_gens_key(struct btree_trans *trans,
+                            struct btree_iter *iter,
+                            struct bkey_s_c k)
 {
+       struct bch_fs *c = trans->c;
        struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
        const struct bch_extent_ptr *ptr;
+       struct bkey_i *u;
+       int ret;
 
        percpu_down_read(&c->mark_lock);
        bkey_for_each_ptr(ptrs, ptr) {
@@ -1859,7 +1875,7 @@ static bool gc_btree_gens_key(struct bch_fs *c, struct bkey_s_c k)
 
                if (ptr_stale(ca, ptr) > 16) {
                        percpu_up_read(&c->mark_lock);
-                       return true;
+                       goto update;
                }
        }
 
@@ -1871,77 +1887,27 @@ static bool gc_btree_gens_key(struct bch_fs *c, struct bkey_s_c k)
                        *gen = ptr->gen;
        }
        percpu_up_read(&c->mark_lock);
+       return 0;
+update:
+       u = bch2_trans_kmalloc(trans, bkey_bytes(k.k));
+       ret = PTR_ERR_OR_ZERO(u);
+       if (ret)
+               return ret;
 
-       return false;
-}
-
-/*
- * For recalculating oldest gen, we only need to walk keys in leaf nodes; btree
- * node pointers currently never have cached pointers that can become stale:
- */
-static int bch2_gc_btree_gens(struct btree_trans *trans, enum btree_id btree_id)
-{
-       struct bch_fs *c = trans->c;
-       struct btree_iter iter;
-       struct bkey_s_c k;
-       struct bkey_buf sk;
-       int ret = 0, commit_err = 0;
-
-       bch2_bkey_buf_init(&sk);
-
-       bch2_trans_iter_init(trans, &iter, btree_id, POS_MIN,
-                            BTREE_ITER_PREFETCH|
-                            BTREE_ITER_NOT_EXTENTS|
-                            BTREE_ITER_ALL_SNAPSHOTS);
-
-       while ((bch2_trans_begin(trans),
-               k = bch2_btree_iter_peek(&iter)).k) {
-               ret = bkey_err(k);
-
-               if (ret == -EINTR)
-                       continue;
-               if (ret)
-                       break;
-
-               c->gc_gens_pos = iter.pos;
-
-               if (gc_btree_gens_key(c, k) && !commit_err) {
-                       bch2_bkey_buf_reassemble(&sk, c, k);
-                       bch2_extent_normalize(c, bkey_i_to_s(sk.k));
-
-                       commit_err =
-                               bch2_trans_update(trans, &iter, sk.k, 0) ?:
-                               bch2_trans_commit(trans, NULL, NULL,
-                                                 BTREE_INSERT_NOWAIT|
-                                                 BTREE_INSERT_NOFAIL);
-                       if (commit_err == -EINTR) {
-                               commit_err = 0;
-                               continue;
-                       }
-               }
-
-               bch2_btree_iter_advance(&iter);
-       }
-       bch2_trans_iter_exit(trans, &iter);
-
-       bch2_bkey_buf_exit(&sk, c);
+       bkey_reassemble(u, k);
 
-       return ret;
+       bch2_extent_normalize(c, bkey_i_to_s(u));
+       return bch2_trans_update(trans, iter, u, 0);
 }
 
-static int bch2_alloc_write_oldest_gen(struct btree_trans *trans, struct btree_iter *iter)
+static int bch2_alloc_write_oldest_gen(struct btree_trans *trans, struct btree_iter *iter,
+                                      struct bkey_s_c k)
 {
        struct bch_dev *ca = bch_dev_bkey_exists(trans->c, iter->pos.inode);
-       struct bkey_s_c k;
        struct bch_alloc_v4 a;
        struct bkey_i_alloc_v4 *a_mut;
        int ret;
 
-       k = bch2_btree_iter_peek_slot(iter);
-       ret = bkey_err(k);
-       if (ret)
-               return ret;
-
        bch2_alloc_to_v4(k, &a);
 
        if (a.oldest_gen == ca->oldest_gen[iter->pos.offset])
@@ -1976,7 +1942,7 @@ int bch2_gc_gens(struct bch_fs *c)
        if (!mutex_trylock(&c->gc_gens_lock))
                return 0;
 
-       trace_gc_gens_start(c);
+       trace_and_count(c, gc_gens_start, c);
        down_read(&c->gc_lock);
        bch2_trans_init(&trans, c, 0, 0);
 
@@ -2001,26 +1967,35 @@ int bch2_gc_gens(struct bch_fs *c)
 
        for (i = 0; i < BTREE_ID_NR; i++)
                if ((1 << i) & BTREE_ID_HAS_PTRS) {
+                       struct btree_iter iter;
+                       struct bkey_s_c k;
+
                        c->gc_gens_btree = i;
                        c->gc_gens_pos = POS_MIN;
-                       ret = bch2_gc_btree_gens(&trans, i);
+                       ret = for_each_btree_key_commit(&trans, iter, i,
+                                       POS_MIN,
+                                       BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS,
+                                       k,
+                                       NULL, NULL,
+                                       BTREE_INSERT_NOFAIL,
+                               gc_btree_gens_key(&trans, &iter, k));
                        if (ret) {
-                               bch_err(c, "error recalculating oldest_gen: %i", ret);
+                               bch_err(c, "error recalculating oldest_gen: %s", bch2_err_str(ret));
                                goto err;
                        }
                }
 
-       for_each_btree_key(&trans, iter, BTREE_ID_alloc, POS_MIN,
-                          BTREE_ITER_PREFETCH, k, ret) {
-               ret = __bch2_trans_do(&trans, NULL, NULL,
-                                     BTREE_INSERT_NOFAIL,
-                               bch2_alloc_write_oldest_gen(&trans, &iter));
-               if (ret) {
-                       bch_err(c, "error writing oldest_gen: %i", ret);
-                       break;
-               }
+       ret = for_each_btree_key_commit(&trans, iter, BTREE_ID_alloc,
+                       POS_MIN,
+                       BTREE_ITER_PREFETCH,
+                       k,
+                       NULL, NULL,
+                       BTREE_INSERT_NOFAIL,
+               bch2_alloc_write_oldest_gen(&trans, &iter, k));
+       if (ret) {
+               bch_err(c, "error writing oldest_gen: %s", bch2_err_str(ret));
+               goto err;
        }
-       bch2_trans_iter_exit(&trans, &iter);
 
        c->gc_gens_btree        = 0;
        c->gc_gens_pos          = POS_MIN;
@@ -2028,7 +2003,7 @@ int bch2_gc_gens(struct bch_fs *c)
        c->gc_count++;
 
        bch2_time_stats_update(&c->times[BCH_TIME_btree_gc], start_time);
-       trace_gc_gens_end(c);
+       trace_and_count(c, gc_gens_end, c);
 err:
        for_each_member_device(ca, c, i) {
                kvfree(ca->oldest_gen);
@@ -2090,7 +2065,7 @@ static int bch2_gc_thread(void *arg)
                ret = bch2_gc_gens(c);
 #endif
                if (ret < 0)
-                       bch_err(c, "btree gc failed: %i", ret);
+                       bch_err(c, "btree gc failed: %s", bch2_err_str(ret));
 
                debug_check_no_locks_held();
        }
@@ -2120,7 +2095,7 @@ int bch2_gc_thread_start(struct bch_fs *c)
 
        p = kthread_create(bch2_gc_thread, c, "bch-gc/%s", c->name);
        if (IS_ERR(p)) {
-               bch_err(c, "error creating gc thread: %li", PTR_ERR(p));
+               bch_err(c, "error creating gc thread: %s", bch2_err_str(PTR_ERR(p)));
                return PTR_ERR(p);
        }