bcachefs: Return errors from for_each_btree_key()

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

18 files changed, 182 insertions, 184 deletions

diff --git a/fs/bcachefs/alloc_background.c b/fs/bcachefs/alloc_background.c
index 4a8f6fa3db1e..a6d3417ac262 100644
--- a/fs/bcachefs/alloc_background.c
+++ b/fs/bcachefs/alloc_background.c
@@ -273,14 +273,14 @@ int bch2_alloc_read(struct bch_fs *c, struct journal_keys *journal_keys)
 
 	bch2_trans_init(&trans, c);
 
-	for_each_btree_key(&trans, iter, BTREE_ID_ALLOC, POS_MIN, 0, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_ALLOC, POS_MIN, 0, k, ret)
 		bch2_alloc_read_key(c, k);
-		bch2_trans_cond_resched(&trans);
-	}
 
-	ret = bch2_trans_exit(&trans);
-	if (ret)
+	ret = bch2_trans_exit(&trans) ?: ret;
+	if (ret) {
+		bch_err(c, "error reading alloc info: %i", ret);
 		return ret;
+	}
 
 	for_each_journal_key(*journal_keys, j)
 		if (j->btree_id == BTREE_ID_ALLOC)
diff --git a/fs/bcachefs/btree_gc.c b/fs/bcachefs/btree_gc.c
index 2650f60b7cd7..3ba0910c2a47 100644
--- a/fs/bcachefs/btree_gc.c
+++ b/fs/bcachefs/btree_gc.c
@@ -289,7 +289,7 @@ static int mark_journal_key(struct bch_fs *c, enum btree_id id,
 	bch2_trans_init(&trans, c);
 
 	for_each_btree_key(&trans, iter, id, bkey_start_pos(&insert->k),
-			   BTREE_ITER_SLOTS, k) {
+			   BTREE_ITER_SLOTS, k, ret) {
 		percpu_down_read(&c->mark_lock);
 		ret = bch2_mark_overwrite(&trans, iter, k, insert, NULL,
 					 BCH_BUCKET_MARK_GC|
@@ -300,7 +300,7 @@ static int mark_journal_key(struct bch_fs *c, enum btree_id id,
 			break;
 	}
 
-	return bch2_trans_exit(&trans);
+	return bch2_trans_exit(&trans) ?: ret;
 }
 
 static int bch2_gc_btrees(struct bch_fs *c, struct journal_keys *journal_keys,
diff --git a/fs/bcachefs/btree_iter.h b/fs/bcachefs/btree_iter.h
index 291c805e3cc5..0a4c6c76e43b 100644
--- a/fs/bcachefs/btree_iter.h
+++ b/fs/bcachefs/btree_iter.h
@@ -238,12 +238,16 @@ static inline struct bkey_s_c __bch2_btree_iter_next(struct btree_iter *iter,
 		: bch2_btree_iter_next(iter);
 }
 
-#define for_each_btree_key(_trans, _iter, _btree_id,  _start, _flags, _k)\
-	for (iter = bch2_trans_get_iter((_trans), (_btree_id),		\
-					(_start), (_flags)),		\
-	     (_k) = __bch2_btree_iter_peek(_iter, _flags);		\
-	     !IS_ERR_OR_NULL((_k).k);					\
-	     (_k) = __bch2_btree_iter_next(_iter, _flags))
+#define for_each_btree_key(_trans, _iter, _btree_id,			\
+			   _start, _flags, _k, _ret)			\
+	for ((_ret) = PTR_ERR_OR_ZERO((_iter) =				\
+			bch2_trans_get_iter((_trans), (_btree_id),	\
+					    (_start), (_flags))) ?:	\
+		      PTR_ERR_OR_ZERO(((_k) =				\
+			__bch2_btree_iter_peek(_iter, _flags)).k);	\
+	     !ret && (_k).k;						\
+	     (_ret) = PTR_ERR_OR_ZERO(((_k) =				\
+			__bch2_btree_iter_next(_iter, _flags)).k))
 
 #define for_each_btree_key_continue(_iter, _flags, _k)			\
 	for ((_k) = __bch2_btree_iter_peek(_iter, _flags);		\
diff --git a/fs/bcachefs/buckets.c b/fs/bcachefs/buckets.c
index e9c5889b2c0f..ff4c61371830 100644
--- a/fs/bcachefs/buckets.c
+++ b/fs/bcachefs/buckets.c
@@ -1035,12 +1035,12 @@ int bch2_mark_key(struct bch_fs *c, struct bkey_s_c k,
 	return ret;
 }
 
-inline bool bch2_mark_overwrite(struct btree_trans *trans,
-				struct btree_iter *iter,
-				struct bkey_s_c old,
-				struct bkey_i *new,
-				struct bch_fs_usage *fs_usage,
-				unsigned flags)
+inline int bch2_mark_overwrite(struct btree_trans *trans,
+			       struct btree_iter *iter,
+			       struct bkey_s_c old,
+			       struct bkey_i *new,
+			       struct bch_fs_usage *fs_usage,
+			       unsigned flags)
 {
 	struct bch_fs		*c = trans->c;
 	struct btree		*b = iter->l[0].b;
@@ -1049,7 +1049,7 @@ inline bool bch2_mark_overwrite(struct btree_trans *trans,
 	if (btree_node_is_extents(b)
 	    ? bkey_cmp(new->k.p, bkey_start_pos(old.k)) <= 0
 	    : bkey_cmp(new->k.p, old.k->p))
-		return false;
+		return 0;
 
 	if (btree_node_is_extents(b)) {
 		switch (bch2_extent_overlap(&new->k, old.k)) {
@@ -1080,24 +1080,24 @@ inline bool bch2_mark_overwrite(struct btree_trans *trans,
 		BUG_ON(sectors >= 0);
 	}
 
-	bch2_mark_key_locked(c, old, false, sectors,
-		fs_usage, trans->journal_res.seq, flags);
-	return true;
+	return bch2_mark_key_locked(c, old, false, sectors, fs_usage,
+				    trans->journal_res.seq, flags) ?: 1;
 }
 
-void bch2_mark_update(struct btree_trans *trans,
-		      struct btree_insert_entry *insert,
-		      struct bch_fs_usage *fs_usage,
-		      unsigned flags)
+int bch2_mark_update(struct btree_trans *trans,
+		     struct btree_insert_entry *insert,
+		     struct bch_fs_usage *fs_usage,
+		     unsigned flags)
 {
 	struct bch_fs		*c = trans->c;
 	struct btree_iter	*iter = insert->iter;
 	struct btree		*b = iter->l[0].b;
 	struct btree_node_iter	node_iter = iter->l[0].iter;
 	struct bkey_packed	*_k;
+	int ret = 0;
 
 	if (!btree_node_type_needs_gc(iter->btree_id))
-		return;
+		return 0;
 
 	bch2_mark_key_locked(c, bkey_i_to_s_c(insert->k), true,
 		bpos_min(insert->k->k.p, b->key.k.p).offset -
@@ -1105,7 +1105,7 @@ void bch2_mark_update(struct btree_trans *trans,
 		fs_usage, trans->journal_res.seq, flags);
 
 	if (unlikely(trans->flags & BTREE_INSERT_NOMARK_OVERWRITES))
-		return;
+		return 0;
 
 	/*
 	 * For non extents, we only mark the new key, not the key being
@@ -1114,19 +1114,22 @@ void bch2_mark_update(struct btree_trans *trans,
 	if ((iter->btree_id == BTREE_ID_ALLOC ||
 	     iter->btree_id == BTREE_ID_EC) &&
 	    !bkey_deleted(&insert->k->k))
-		return;
+		return 0;
 
 	while ((_k = bch2_btree_node_iter_peek_filter(&node_iter, b,
 						      KEY_TYPE_discard))) {
 		struct bkey		unpacked;
 		struct bkey_s_c		k = bkey_disassemble(b, _k, &unpacked);
 
-		if (!bch2_mark_overwrite(trans, iter, k, insert->k,
-					 fs_usage, flags))
+		ret = bch2_mark_overwrite(trans, iter, k, insert->k,
+					  fs_usage, flags);
+		if (ret <= 0)
 			break;
 
 		bch2_btree_node_iter_advance(&node_iter, b);
 	}
+
+	return ret;
 }
 
 void bch2_trans_fs_usage_apply(struct btree_trans *trans,
diff --git a/fs/bcachefs/buckets.h b/fs/bcachefs/buckets.h
index 90fffee1c289..c51192fae503 100644
--- a/fs/bcachefs/buckets.h
+++ b/fs/bcachefs/buckets.h
@@ -254,11 +254,11 @@ int bch2_mark_key(struct bch_fs *, struct bkey_s_c,
 int bch2_fs_usage_apply(struct bch_fs *, struct bch_fs_usage *,
 			struct disk_reservation *);
 
-bool bch2_mark_overwrite(struct btree_trans *, struct btree_iter *,
-			 struct bkey_s_c, struct bkey_i *,
-			 struct bch_fs_usage *, unsigned);
-void bch2_mark_update(struct btree_trans *, struct btree_insert_entry *,
-		      struct bch_fs_usage *, unsigned);
+int bch2_mark_overwrite(struct btree_trans *, struct btree_iter *,
+			struct bkey_s_c, struct bkey_i *,
+			struct bch_fs_usage *, unsigned);
+int bch2_mark_update(struct btree_trans *, struct btree_insert_entry *,
+		     struct bch_fs_usage *, unsigned);
 void bch2_trans_fs_usage_apply(struct btree_trans *, struct bch_fs_usage *);
 
 /* disk reservations: */
diff --git a/fs/bcachefs/dirent.c b/fs/bcachefs/dirent.c
index 4479a9f55ddf..71971b3cc851 100644
--- a/fs/bcachefs/dirent.c
+++ b/fs/bcachefs/dirent.c
@@ -333,14 +333,10 @@ int bch2_empty_dir_trans(struct btree_trans *trans, u64 dir_inum)
 {
 	struct btree_iter *iter;
 	struct bkey_s_c k;
-	int ret = 0;
-
-	iter = bch2_trans_get_iter(trans, BTREE_ID_DIRENTS,
-				   POS(dir_inum, 0), 0);
-	if (IS_ERR(iter))
-		return PTR_ERR(iter);
+	int ret;
 
-	for_each_btree_key_continue(iter, 0, k) {
+	for_each_btree_key(trans, iter, BTREE_ID_DIRENTS,
+			   POS(dir_inum, 0), 0, k, ret) {
 		if (k.k->p.inode > dir_inum)
 			break;
 
@@ -369,6 +365,7 @@ int bch2_readdir(struct bch_fs *c, struct file *file,
 	struct bkey_s_c k;
 	struct bkey_s_c_dirent dirent;
 	unsigned len;
+	int ret;
 
 	if (!dir_emit_dots(file, ctx))
 		return 0;
@@ -376,7 +373,7 @@ int bch2_readdir(struct bch_fs *c, struct file *file,
 	bch2_trans_init(&trans, c);
 
 	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS,
-			   POS(inode->v.i_ino, ctx->pos), 0, k) {
+			   POS(inode->v.i_ino, ctx->pos), 0, k, ret) {
 		if (k.k->type != KEY_TYPE_dirent)
 			continue;
 
@@ -401,7 +398,7 @@ int bch2_readdir(struct bch_fs *c, struct file *file,
 
 		ctx->pos = k.k->p.offset + 1;
 	}
-	bch2_trans_exit(&trans);
+	ret = bch2_trans_exit(&trans) ?: ret;
 
-	return 0;
+	return ret;
 }
diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
index 47d197ed5c99..063f91fc1b09 100644
--- a/fs/bcachefs/ec.c
+++ b/fs/bcachefs/ec.c
@@ -679,10 +679,8 @@ retry:
 	bch2_trans_begin(&trans);
 
 	/* XXX: start pos hint */
-	iter = bch2_trans_get_iter(&trans, BTREE_ID_EC, POS_MIN,
-				   BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
-
-	for_each_btree_key_continue(iter, BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_EC, POS_MIN,
+			   BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k, ret) {
 		if (bkey_cmp(k.k->p, POS(0, U32_MAX)) > 0)
 			break;
 
@@ -690,7 +688,8 @@ retry:
 			goto found_slot;
 	}
 
-	ret = -ENOSPC;
+	if (!ret)
+		ret = -ENOSPC;
 	goto out;
 found_slot:
 	ret = ec_stripe_mem_alloc(c, iter);
@@ -1249,14 +1248,14 @@ int bch2_stripes_read(struct bch_fs *c, struct journal_keys *journal_keys)
 
 	bch2_trans_init(&trans, c);
 
-	for_each_btree_key(&trans, iter, BTREE_ID_EC, POS_MIN, 0, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_EC, POS_MIN, 0, k, ret)
 		bch2_stripe_read_key(c, k);
-		bch2_trans_cond_resched(&trans);
-	}
 
-	ret = bch2_trans_exit(&trans);
-	if (ret)
+	ret = bch2_trans_exit(&trans) ?: ret;
+	if (ret) {
+		bch_err(c, "error reading stripes: %i", ret);
 		return ret;
+	}
 
 	for_each_journal_key(*journal_keys, i)
 		if (i->btree_id == BTREE_ID_EC)
diff --git a/fs/bcachefs/extents.c b/fs/bcachefs/extents.c
index 2e7c3e82f03b..257c862c9856 100644
--- a/fs/bcachefs/extents.c
+++ b/fs/bcachefs/extents.c
@@ -1632,13 +1632,14 @@ bool bch2_check_range_allocated(struct bch_fs *c, struct bpos pos, u64 size,
 	struct bpos end = pos;
 	struct bkey_s_c k;
 	bool ret = true;
+	int err;
 
 	end.offset += size;
 
 	bch2_trans_init(&trans, c);
 
 	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS, pos,
-			   BTREE_ITER_SLOTS, k) {
+			   BTREE_ITER_SLOTS, k, err) {
 		if (bkey_cmp(bkey_start_pos(k.k), end) >= 0)
 			break;
 
diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
index c8f6104553aa..f76dd4d89f25 100644
--- a/fs/bcachefs/fs-io.c
+++ b/fs/bcachefs/fs-io.c
@@ -2139,7 +2139,7 @@ static inline int range_has_data(struct bch_fs *c,
 
 	bch2_trans_init(&trans, c);
 
-	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS, start, 0, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS, start, 0, k, ret) {
 		if (bkey_cmp(bkey_start_pos(k.k), end) >= 0)
 			break;
 
@@ -2732,7 +2732,7 @@ static loff_t bch2_seek_data(struct file *file, u64 offset)
 	bch2_trans_init(&trans, c);
 
 	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS,
-			   POS(inode->v.i_ino, offset >> 9), 0, k) {
+			   POS(inode->v.i_ino, offset >> 9), 0, k, ret) {
 		if (k.k->p.inode != inode->v.i_ino) {
 			break;
 		} else if (bkey_extent_is_data(k.k)) {
@@ -2742,7 +2742,7 @@ static loff_t bch2_seek_data(struct file *file, u64 offset)
 			break;
 	}
 
-	ret = bch2_trans_exit(&trans);
+	ret = bch2_trans_exit(&trans) ?: ret;
 	if (ret)
 		return ret;
 
@@ -2806,7 +2806,7 @@ static loff_t bch2_seek_hole(struct file *file, u64 offset)
 
 	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS,
 			   POS(inode->v.i_ino, offset >> 9),
-			   BTREE_ITER_SLOTS, k) {
+			   BTREE_ITER_SLOTS, k, ret) {
 		if (k.k->p.inode != inode->v.i_ino) {
 			next_hole = bch2_next_pagecache_hole(&inode->v,
 					offset, MAX_LFS_FILESIZE);
@@ -2823,7 +2823,7 @@ static loff_t bch2_seek_hole(struct file *file, u64 offset)
 		}
 	}
 
-	ret = bch2_trans_exit(&trans);
+	ret = bch2_trans_exit(&trans) ?: ret;
 	if (ret)
 		return ret;
 
diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index 6e377a0e176f..ba4b4e942f0c 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -1210,7 +1210,7 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
 	bch2_trans_init(&trans, c);
 
 	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS,
-			   POS(ei->v.i_ino, start >> 9), 0, k)
+			   POS(ei->v.i_ino, start >> 9), 0, k, ret)
 		if (bkey_extent_is_data(k.k) ||
 		    k.k->type == KEY_TYPE_reservation) {
 			if (bkey_cmp(bkey_start_pos(k.k),
@@ -1220,17 +1220,17 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
 			if (have_extent) {
 				ret = bch2_fill_extent(info, &tmp.k, 0);
 				if (ret)
-					goto out;
+					break;
 			}
 
 			bkey_reassemble(&tmp.k, k);
 			have_extent = true;
 		}
 
-	if (have_extent)
+	if (!ret && have_extent)
 		ret = bch2_fill_extent(info, &tmp.k, FIEMAP_EXTENT_LAST);
-out:
-	bch2_trans_exit(&trans);
+
+	ret = bch2_trans_exit(&trans) ?: ret;
 	return ret < 0 ? ret : 0;
 }
 
diff --git a/fs/bcachefs/fsck.c b/fs/bcachefs/fsck.c
index 9db01437315b..ade3446d8dc3 100644
--- a/fs/bcachefs/fsck.c
+++ b/fs/bcachefs/fsck.c
@@ -21,8 +21,10 @@ static s64 bch2_count_inode_sectors(struct btree_trans *trans, u64 inum)
 	struct btree_iter *iter;
 	struct bkey_s_c k;
 	u64 sectors = 0;
+	int ret;
 
-	for_each_btree_key(trans, iter, BTREE_ID_EXTENTS, POS(inum, 0), 0, k) {
+	for_each_btree_key(trans, iter, BTREE_ID_EXTENTS,
+			   POS(inum, 0), 0, k, ret) {
 		if (k.k->p.inode != inum)
 			break;
 
@@ -30,7 +32,9 @@ static s64 bch2_count_inode_sectors(struct btree_trans *trans, u64 inum)
 			sectors += k.k->size;
 	}
 
-	return bch2_trans_iter_free(trans, iter) ?: sectors;
+	bch2_trans_iter_free(trans, iter);
+
+	return ret ?: sectors;
 }
 
 static int remove_dirent(struct btree_trans *trans,
@@ -942,7 +946,7 @@ next:
 			goto up;
 
 		for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS,
-				   POS(e->inum, e->offset + 1), 0, k) {
+				   POS(e->inum, e->offset + 1), 0, k, ret) {
 			if (k.k->p.inode != e->inum)
 				break;
 
@@ -985,7 +989,7 @@ next:
 			}
 			goto next;
 		}
-		ret = bch2_trans_iter_free(&trans, iter);
+		ret = bch2_trans_iter_free(&trans, iter) ?: ret;
 		if (ret) {
 			bch_err(c, "btree error %i in fsck", ret);
 			goto err;
@@ -1087,7 +1091,7 @@ static int bch2_gc_walk_dirents(struct bch_fs *c, nlink_table *links,
 
 	inc_link(c, links, range_start, range_end, BCACHEFS_ROOT_INO, false);
 
-	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS, POS_MIN, 0, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS, POS_MIN, 0, k, ret) {
 		switch (k.k->type) {
 		case KEY_TYPE_dirent:
 			d = bkey_s_c_to_dirent(k);
@@ -1105,7 +1109,7 @@ static int bch2_gc_walk_dirents(struct bch_fs *c, nlink_table *links,
 
 		bch2_trans_cond_resched(&trans);
 	}
-	ret = bch2_trans_exit(&trans);
+	ret = bch2_trans_exit(&trans) ?: ret;
 	if (ret)
 		bch_err(c, "error in fs gc: btree error %i while walking dirents", ret);
 
@@ -1432,15 +1436,12 @@ static int check_inodes_fast(struct bch_fs *c)
 	struct btree_iter *iter;
 	struct bkey_s_c k;
 	struct bkey_s_c_inode inode;
-	int ret = 0, ret2;
+	int ret;
 
 	bch2_trans_init(&trans, c);
 	bch2_trans_preload_iters(&trans);
 
-	iter = bch2_trans_get_iter(&trans, BTREE_ID_INODES,
-				   POS_MIN, 0);
-
-	for_each_btree_key_continue(iter, 0, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_INODES, POS_MIN, 0, k, ret) {
 		if (k.k->type != KEY_TYPE_inode)
 			continue;
 
@@ -1456,10 +1457,9 @@ static int check_inodes_fast(struct bch_fs *c)
 				break;
 		}
 	}
+	BUG_ON(ret == -EINTR);
 
-	ret2 = bch2_trans_exit(&trans);
-
-	return ret ?: ret2;
+	return bch2_trans_exit(&trans) ?: ret;
 }
 
 /*
diff --git a/fs/bcachefs/io.c b/fs/bcachefs/io.c
index 71481b9728f5..b07b0f92d4f9 100644
--- a/fs/bcachefs/io.c
+++ b/fs/bcachefs/io.c
@@ -1326,7 +1326,7 @@ static void bch2_read_retry(struct bch_fs *c, struct bch_read_bio *rbio,
 retry:
 	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS,
 			   POS(inode, bvec_iter.bi_sector),
-			   BTREE_ITER_SLOTS, k) {
+			   BTREE_ITER_SLOTS, k, ret) {
 		BKEY_PADDED(k) tmp;
 		unsigned bytes;
 
@@ -1357,8 +1357,8 @@ retry:
 	 * If we get here, it better have been because there was an error
 	 * reading a btree node
 	 */
-	BUG_ON(!btree_iter_err(iter));
-	__bcache_io_error(c, "btree IO error");
+	BUG_ON(!ret);
+	__bcache_io_error(c, "btree IO error: %i", ret);
 err:
 	rbio->bio.bi_status = BLK_STS_IOERR;
 out:
@@ -1871,6 +1871,7 @@ void bch2_read(struct bch_fs *c, struct bch_read_bio *rbio, u64 inode)
 	unsigned flags = BCH_READ_RETRY_IF_STALE|
 		BCH_READ_MAY_PROMOTE|
 		BCH_READ_USER_MAPPED;
+	int ret;
 
 	bch2_trans_init(&trans, c);
 
@@ -1883,7 +1884,7 @@ void bch2_read(struct bch_fs *c, struct bch_read_bio *rbio, u64 inode)
 
 	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS,
 			   POS(inode, rbio->bio.bi_iter.bi_sector),
-			   BTREE_ITER_SLOTS, k) {
+			   BTREE_ITER_SLOTS, k, ret) {
 		BKEY_PADDED(k) tmp;
 		unsigned bytes;
 
@@ -1915,8 +1916,8 @@ void bch2_read(struct bch_fs *c, struct bch_read_bio *rbio, u64 inode)
 	 * If we get here, it better have been because there was an error
 	 * reading a btree node
 	 */
-	BUG_ON(!btree_iter_err(iter));
-	bcache_io_error(c, &rbio->bio, "btree IO error");
+	BUG_ON(!ret);
+	bcache_io_error(c, &rbio->bio, "btree IO error: %i", ret);
 
 	bch2_trans_exit(&trans);
 	bch2_rbio_done(rbio);
diff --git a/fs/bcachefs/move.c b/fs/bcachefs/move.c
index 9793896bee77..1ad585ee27ca 100644
--- a/fs/bcachefs/move.c
+++ b/fs/bcachefs/move.c
@@ -630,7 +630,7 @@ static int bch2_gc_data_replicas(struct bch_fs *c)
 	bch2_replicas_gc_start(c, (1 << BCH_DATA_USER)|(1 << BCH_DATA_CACHED));
 
 	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS, POS_MIN,
-			   BTREE_ITER_PREFETCH, k) {
+			   BTREE_ITER_PREFETCH, k, ret) {
 		ret = bch2_mark_bkey_replicas(c, k);
 		if (ret)
 			break;
diff --git a/fs/bcachefs/quota.c b/fs/bcachefs/quota.c
index a4f75d53b42c..b78df735d94c 100644
--- a/fs/bcachefs/quota.c
+++ b/fs/bcachefs/quota.c
@@ -364,7 +364,7 @@ static int bch2_quota_init_type(struct bch_fs *c, enum quota_types type)
 	bch2_trans_init(&trans, c);
 
 	for_each_btree_key(&trans, iter, BTREE_ID_QUOTAS, POS(type, 0),
-			   BTREE_ITER_PREFETCH, k) {
+			   BTREE_ITER_PREFETCH, k, ret) {
 		if (k.k->p.inode != type)
 			break;
 
@@ -436,7 +436,7 @@ int bch2_fs_quota_read(struct bch_fs *c)
 	bch2_trans_init(&trans, c);
 
 	for_each_btree_key(&trans, iter, BTREE_ID_INODES, POS_MIN,
-			   BTREE_ITER_PREFETCH, k) {
+			   BTREE_ITER_PREFETCH, k, ret) {
 		switch (k.k->type) {
 		case KEY_TYPE_inode:
 			ret = bch2_inode_unpack(bkey_s_c_to_inode(k), &u);
diff --git a/fs/bcachefs/str_hash.h b/fs/bcachefs/str_hash.h
index 0ed28d7f074d..c47af32ce983 100644
--- a/fs/bcachefs/str_hash.h
+++ b/fs/bcachefs/str_hash.h
@@ -134,14 +134,11 @@ bch2_hash_lookup(struct btree_trans *trans,
 {
 	struct btree_iter *iter;
 	struct bkey_s_c k;
+	int ret;
 
-	iter = bch2_trans_get_iter(trans, desc.btree_id,
-				   POS(inode, desc.hash_key(info, key)),
-				   BTREE_ITER_SLOTS|flags);
-	if (IS_ERR(iter))
-		return iter;
-
-	for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
+	for_each_btree_key(trans, iter, desc.btree_id,
+			   POS(inode, desc.hash_key(info, key)),
+			   BTREE_ITER_SLOTS|flags, k, ret) {
 		if (iter->pos.inode != inode)
 			break;
 
@@ -156,7 +153,7 @@ bch2_hash_lookup(struct btree_trans *trans,
 		}
 	}
 
-	return IS_ERR(k.k) ? ERR_CAST(k.k) : ERR_PTR(-ENOENT);
+	return ERR_PTR(ret ?: -ENOENT);
 }
 
 static __always_inline struct btree_iter *
@@ -167,14 +164,11 @@ bch2_hash_hole(struct btree_trans *trans,
 {
 	struct btree_iter *iter;
 	struct bkey_s_c k;
+	int ret;
 
-	iter = bch2_trans_get_iter(trans, desc.btree_id,
-				   POS(inode, desc.hash_key(info, key)),
-				   BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
-	if (IS_ERR(iter))
-		return iter;
-
-	for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
+	for_each_btree_key(trans, iter, desc.btree_id,
+			   POS(inode, desc.hash_key(info, key)),
+			   BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k, ret) {
 		if (iter->pos.inode != inode)
 			break;
 
@@ -182,7 +176,7 @@ bch2_hash_hole(struct btree_trans *trans,
 			return iter;
 	}
 
-	return IS_ERR(k.k) ? ERR_CAST(k.k) : ERR_PTR(-ENOSPC);
+	return ERR_PTR(ret ?: -ENOSPC);
 }
 
 static __always_inline
@@ -224,15 +218,11 @@ int bch2_hash_set(struct btree_trans *trans,
 	struct btree_iter *iter, *slot = NULL;
 	struct bkey_s_c k;
 	bool found = false;
-	int ret = 0;
-
-	iter = bch2_trans_get_iter(trans, desc.btree_id,
-			POS(inode, desc.hash_bkey(info, bkey_i_to_s_c(insert))),
-			BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
-	if (IS_ERR(iter))
-		return PTR_ERR(iter);
+	int ret;
 
-	for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
+	for_each_btree_key(trans, iter, desc.btree_id,
+			   POS(inode, desc.hash_bkey(info, bkey_i_to_s_c(insert))),
+			   BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k, ret) {
 		if (iter->pos.inode != inode)
 			break;
 
@@ -256,9 +246,10 @@ int bch2_hash_set(struct btree_trans *trans,
 	}
 
 	if (slot)
-		bch2_trans_iter_free(trans, iter);
+		bch2_trans_iter_free(trans, slot);
+	bch2_trans_iter_free(trans, iter);
 
-	return bch2_trans_iter_free(trans, iter) ?: -ENOSPC;
+	return ret ?: -ENOSPC;
 found:
 	found = true;
 not_found:
diff --git a/fs/bcachefs/sysfs.c b/fs/bcachefs/sysfs.c
index f4b70f66d0ac..ee4c0764d4ad 100644
--- a/fs/bcachefs/sysfs.c
+++ b/fs/bcachefs/sysfs.c
@@ -289,13 +289,14 @@ static ssize_t bch2_compression_stats(struct bch_fs *c, char *buf)
 	    nr_compressed_extents = 0,
 	    compressed_sectors_compressed = 0,
 	    compressed_sectors_uncompressed = 0;
+	int ret;
 
 	if (!test_bit(BCH_FS_STARTED, &c->flags))
 		return -EPERM;
 
 	bch2_trans_init(&trans, c);
 
-	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS, POS_MIN, 0, k)
+	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS, POS_MIN, 0, k, ret)
 		if (k.k->type == KEY_TYPE_extent) {
 			struct bkey_s_c_extent e = bkey_s_c_to_extent(k);
 			const union bch_extent_entry *entry;
@@ -317,7 +318,10 @@ static ssize_t bch2_compression_stats(struct bch_fs *c, char *buf)
 				break;
 			}
 		}
-	bch2_trans_exit(&trans);
+
+	ret = bch2_trans_exit(&trans) ?: ret;
+	if (ret)
+		return ret;
 
 	return scnprintf(buf, PAGE_SIZE,
 			"uncompressed data:\n"
diff --git a/fs/bcachefs/tests.c b/fs/bcachefs/tests.c
index c8682fe674f6..0f5a3ed13f3e 100644
--- a/fs/bcachefs/tests.c
+++ b/fs/bcachefs/tests.c
@@ -116,7 +116,8 @@ static void test_iterate(struct bch_fs *c, u64 nr)
 
 	i = 0;
 
-	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS, POS(0, 0), 0, k)
+	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS,
+			   POS_MIN, 0, k, ret)
 		BUG_ON(k.k->p.offset != i++);
 
 	BUG_ON(i != nr);
@@ -161,7 +162,8 @@ static void test_iterate_extents(struct bch_fs *c, u64 nr)
 
 	i = 0;
 
-	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS, POS(0, 0), 0, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS,
+			   POS_MIN, 0, k, ret) {
 		BUG_ON(bkey_start_offset(k.k) != i);
 		i = k.k->p.offset;
 	}
@@ -209,7 +211,8 @@ static void test_iterate_slots(struct bch_fs *c, u64 nr)
 
 	i = 0;
 
-	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS, POS(0, 0), 0, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS, POS_MIN,
+			   0, k, ret) {
 		BUG_ON(k.k->p.offset != i);
 		i += 2;
 	}
@@ -221,8 +224,8 @@ static void test_iterate_slots(struct bch_fs *c, u64 nr)
 
 	i = 0;
 
-	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS, POS(0, 0),
-			   BTREE_ITER_SLOTS, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS, POS_MIN,
+			   BTREE_ITER_SLOTS, k, ret) {
 		BUG_ON(bkey_deleted(k.k) != (i & 1));
 		BUG_ON(k.k->p.offset != i++);
 
@@ -263,7 +266,8 @@ static void test_iterate_slots_extents(struct bch_fs *c, u64 nr)
 
 	i = 0;
 
-	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS, POS(0, 0), 0, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS, POS_MIN,
+			   0, k, ret) {
 		BUG_ON(bkey_start_offset(k.k) != i + 8);
 		BUG_ON(k.k->size != 8);
 		i += 16;
@@ -276,8 +280,8 @@ static void test_iterate_slots_extents(struct bch_fs *c, u64 nr)
 
 	i = 0;
 
-	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS, POS(0, 0),
-			   BTREE_ITER_SLOTS, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_EXTENTS, POS_MIN,
+			   BTREE_ITER_SLOTS, k, ret) {
 		BUG_ON(bkey_deleted(k.k) != !(i % 16));
 
 		BUG_ON(bkey_start_offset(k.k) != i);
@@ -501,10 +505,8 @@ static void seq_insert(struct bch_fs *c, u64 nr)
 
 	bch2_trans_init(&trans, c);
 
-	iter = bch2_trans_get_iter(&trans, BTREE_ID_DIRENTS, POS_MIN,
-				   BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
-
-	for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS, POS_MIN,
+			   BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k, ret) {
 		insert.k.p = iter->pos;
 
 		bch2_trans_update(&trans, BTREE_INSERT_ENTRY(iter, &insert.k_i));
@@ -522,10 +524,11 @@ static void seq_lookup(struct bch_fs *c, u64 nr)
 	struct btree_trans trans;
 	struct btree_iter *iter;
 	struct bkey_s_c k;
+	int ret;
 
 	bch2_trans_init(&trans, c);
 
-	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS, POS_MIN, 0, k)
+	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS, POS_MIN, 0, k, ret)
 		;
 	bch2_trans_exit(&trans);
 }
@@ -539,10 +542,8 @@ static void seq_overwrite(struct bch_fs *c, u64 nr)
 
 	bch2_trans_init(&trans, c);
 
-	iter = bch2_trans_get_iter(&trans, BTREE_ID_DIRENTS, POS_MIN,
-				   BTREE_ITER_INTENT);
-
-	for_each_btree_key_continue(iter, 0, k) {
+	for_each_btree_key(&trans, iter, BTREE_ID_DIRENTS, POS_MIN,
+			   BTREE_ITER_INTENT, k, ret) {
 		struct bkey_i_cookie u;
 
 		bkey_reassemble(&u.k_i, k);
diff --git a/fs/bcachefs/xattr.c b/fs/bcachefs/xattr.c
index 68ece7c0ee7a..99fb42225508 100644
--- a/fs/bcachefs/xattr.c
+++ b/fs/bcachefs/xattr.c
@@ -198,55 +198,54 @@ int bch2_xattr_set(struct btree_trans *trans, u64 inum,
 	return ret;
 }
 
-static void __bch2_xattr_emit(const char *prefix,
-			      const char *name, size_t name_len,
-			      char **buffer, size_t *buffer_size,
-			      ssize_t *ret)
+struct xattr_buf {
+	char		*buf;
+	size_t		len;
+	size_t		used;
+};
+
+static int __bch2_xattr_emit(const char *prefix,
+			     const char *name, size_t name_len,
+			     struct xattr_buf *buf)
 {
 	const size_t prefix_len = strlen(prefix);
 	const size_t total_len = prefix_len + name_len + 1;
 
-	if (*buffer) {
-		if (total_len > *buffer_size) {
-			*ret = -ERANGE;
-			return;
-		}
+	if (buf->buf) {
+		if (buf->used + total_len > buf->len)
+			return -ERANGE;
 
-		memcpy(*buffer, prefix, prefix_len);
-		memcpy(*buffer + prefix_len,
+		memcpy(buf->buf + buf->used, prefix, prefix_len);
+		memcpy(buf->buf + buf->used + prefix_len,
 		       name, name_len);
-		(*buffer)[prefix_len + name_len] = '\0';
-
-		*buffer		+= total_len;
-		*buffer_size	-= total_len;
+		buf->buf[buf->used + prefix_len + name_len] = '\0';
 	}
 
-	*ret += total_len;
+	buf->used += total_len;
+	return 0;
 }
 
-static void bch2_xattr_emit(struct dentry *dentry,
+static int bch2_xattr_emit(struct dentry *dentry,
 			    const struct bch_xattr *xattr,
-			    char **buffer, size_t *buffer_size,
-			    ssize_t *ret)
+			    struct xattr_buf *buf)
 {
 	const struct xattr_handler *handler =
 		bch2_xattr_type_to_handler(xattr->x_type);
 
-	if (handler && (!handler->list || handler->list(dentry)))
-		__bch2_xattr_emit(handler->prefix ?: handler->name,
-				  xattr->x_name, xattr->x_name_len,
-				  buffer, buffer_size, ret);
+	return handler && (!handler->list || handler->list(dentry))
+		? __bch2_xattr_emit(handler->prefix ?: handler->name,
+				    xattr->x_name, xattr->x_name_len, buf)
+		: 0;
 }
 
-static void bch2_xattr_list_bcachefs(struct bch_fs *c,
-				     struct bch_inode_info *inode,
-				     char **buffer,
-				     size_t *buffer_size,
-				     ssize_t *ret,
-				     bool all)
+static int bch2_xattr_list_bcachefs(struct bch_fs *c,
+				    struct bch_inode_info *inode,
+				    struct xattr_buf *buf,
+				    bool all)
 {
 	const char *prefix = all ? "bcachefs_effective." : "bcachefs.";
 	unsigned id;
+	int ret = 0;
 	u64 v;
 
 	for (id = 0; id < Inode_opt_nr; id++) {
@@ -258,13 +257,13 @@ static void bch2_xattr_list_bcachefs(struct bch_fs *c,
 		    !(inode->ei_inode.bi_fields_set & (1 << id)))
 			continue;
 
-		__bch2_xattr_emit(prefix,
-				  bch2_inode_opts[id],
-				  strlen(bch2_inode_opts[id]),
-				  buffer, buffer_size, ret);
-		if (*ret < 0)
+		ret = __bch2_xattr_emit(prefix, bch2_inode_opts[id],
+					strlen(bch2_inode_opts[id]), buf);
+		if (ret)
 			break;
 	}
+
+	return ret;
 }
 
 ssize_t bch2_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
@@ -274,13 +273,14 @@ ssize_t bch2_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 	struct btree_trans trans;
 	struct btree_iter *iter;
 	struct bkey_s_c k;
+	struct xattr_buf buf = { .buf = buffer, .len = buffer_size };
 	u64 inum = dentry->d_inode->i_ino;
-	ssize_t ret = 0;
+	int ret;
 
 	bch2_trans_init(&trans, c);
 
 	for_each_btree_key(&trans, iter, BTREE_ID_XATTRS,
-			   POS(inum, 0), 0, k) {
+			   POS(inum, 0), 0, k, ret) {
 		BUG_ON(k.k->p.inode < inum);
 
 		if (k.k->p.inode > inum)
@@ -289,27 +289,24 @@ ssize_t bch2_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 		if (k.k->type != KEY_TYPE_xattr)
 			continue;
 
-		bch2_xattr_emit(dentry, bkey_s_c_to_xattr(k).v,
-				&buffer, &buffer_size, &ret);
-		if (ret < 0)
+		ret = bch2_xattr_emit(dentry, bkey_s_c_to_xattr(k).v, &buf);
+		if (ret)
 			break;
 	}
-	bch2_trans_exit(&trans);
+	ret = bch2_trans_exit(&trans) ?: ret;
 
-	if (ret < 0)
+	if (ret)
 		return ret;
 
-	bch2_xattr_list_bcachefs(c, inode, &buffer,
-				 &buffer_size, &ret, false);
-	if (ret < 0)
+	ret = bch2_xattr_list_bcachefs(c, inode, &buf, false);
+	if (ret)
 		return ret;
 
-	bch2_xattr_list_bcachefs(c, inode, &buffer,
-				 &buffer_size, &ret, true);
-	if (ret < 0)
+	ret = bch2_xattr_list_bcachefs(c, inode, &buf, true);
+	if (ret)
 		return ret;
 
-	return ret;
+	return buf.used;
 }
 
 static int bch2_xattr_get_handler(const struct xattr_handler *handler,