bcachefs: Always check for transaction restarts

On transaction restart iterators won't be locked anymore - make sure
we're always checking for errors.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/acl.c

@@ -222,6 +222,8 @@ struct posix_acl *bch2_get_acl(struct mnt_idmap *idmap,
 	struct btree_iter *iter;
 	struct bkey_s_c_xattr xattr;
 	struct posix_acl *acl = NULL;
+	struct bkey_s_c k;
+	int ret;
 
 	bch2_trans_init(&trans, c, 0, 0);
 retry:
@@ -240,7 +242,14 @@ struct posix_acl *bch2_get_acl(struct mnt_idmap *idmap,
 		goto out;
 	}
 
-	xattr = bkey_s_c_to_xattr(bch2_btree_iter_peek_slot(iter));
+	k = bch2_btree_iter_peek_slot(iter);
+	ret = bkey_err(k);
+	if (ret) {
+		acl = ERR_PTR(ret);
+		goto out;
+	}
+
+	xattr = bkey_s_c_to_xattr(k);
 	acl = bch2_acl_from_disk(xattr_val(xattr.v),
 			le16_to_cpu(xattr.v->x_val_len));
 
@@ -358,6 +367,7 @@ int bch2_acl_chmod(struct btree_trans *trans,
 	struct bkey_s_c_xattr xattr;
 	struct bkey_i_xattr *new;
 	struct posix_acl *acl;
+	struct bkey_s_c k;
 	int ret;
 
 	iter = bch2_hash_lookup(trans, bch2_xattr_hash_desc,
@@ -368,7 +378,11 @@ int bch2_acl_chmod(struct btree_trans *trans,
 	if (ret)
 		return ret == -ENOENT ? 0 : ret;
 
-	xattr = bkey_s_c_to_xattr(bch2_btree_iter_peek_slot(iter));
+	k = bch2_btree_iter_peek_slot(iter);
+	xattr = bkey_s_c_to_xattr(k);
+	if (ret)
+		goto err;
+
 	acl = bch2_acl_from_disk(xattr_val(xattr.v),
 			le16_to_cpu(xattr.v->x_val_len));
 	ret = PTR_ERR_OR_ZERO(acl);

fs/bcachefs/alloc_background.c

@@ -374,7 +374,7 @@ int bch2_alloc_write(struct bch_fs *c, unsigned flags)
 				percpu_ref_put(&ca->ref);
 				goto err;
 			}
-			bch2_btree_iter_next_slot(iter);
+			bch2_btree_iter_advance(iter);
 		}
 	}
 err:

fs/bcachefs/btree_cache.c

@@ -973,9 +973,9 @@ struct btree *bch2_btree_node_get_noiter(struct bch_fs *c,
 	return b;
 }
 
-void bch2_btree_node_prefetch(struct bch_fs *c, struct btree_iter *iter,
-			      const struct bkey_i *k,
-			      enum btree_id btree_id, unsigned level)
+int bch2_btree_node_prefetch(struct bch_fs *c, struct btree_iter *iter,
+			     const struct bkey_i *k,
+			     enum btree_id btree_id, unsigned level)
 {
 	struct btree_cache *bc = &c->btree_cache;
 	struct btree *b;
@@ -985,9 +985,10 @@ void bch2_btree_node_prefetch(struct bch_fs *c, struct btree_iter *iter,
 
 	b = btree_cache_find(bc, k);
 	if (b)
-		return;
+		return 0;
 
-	bch2_btree_node_fill(c, iter, k, btree_id, level, SIX_LOCK_read, false);
+	b = bch2_btree_node_fill(c, iter, k, btree_id, level, SIX_LOCK_read, false);
+	return PTR_ERR_OR_ZERO(b);
 }
 
 void bch2_btree_node_evict(struct bch_fs *c, const struct bkey_i *k)

fs/bcachefs/btree_cache.h

@@ -27,8 +27,8 @@ struct btree *bch2_btree_node_get(struct btree_trans *, struct btree_iter *,
 struct btree *bch2_btree_node_get_noiter(struct bch_fs *, const struct bkey_i *,
 					 enum btree_id, unsigned, bool);
 
-void bch2_btree_node_prefetch(struct bch_fs *, struct btree_iter *,
-			      const struct bkey_i *, enum btree_id, unsigned);
+int bch2_btree_node_prefetch(struct bch_fs *, struct btree_iter *,
+			     const struct bkey_i *, enum btree_id, unsigned);
 
 void bch2_btree_node_evict(struct bch_fs *, const struct bkey_i *);
 

fs/bcachefs/btree_iter.c

@@ -1142,7 +1142,7 @@ static inline int btree_iter_lock_root(struct btree_iter *iter,
 }
 
 noinline
-static void btree_iter_prefetch(struct btree_iter *iter)
+static int btree_iter_prefetch(struct btree_iter *iter)
 {
 	struct bch_fs *c = iter->trans->c;
 	struct btree_iter_level *l = &iter->l[iter->level];
@@ -1153,10 +1153,11 @@ static void btree_iter_prefetch(struct btree_iter *iter)
 		? (iter->level > 1 ? 0 :  2)
 		: (iter->level > 1 ? 1 : 16);
 	bool was_locked = btree_node_locked(iter, iter->level);
+	int ret = 0;
 
 	bch2_bkey_buf_init(&tmp);
 
-	while (nr) {
+	while (nr && !ret) {
 		if (!bch2_btree_node_relock(iter, iter->level))
 			break;
 
@@ -1166,14 +1167,15 @@ static void btree_iter_prefetch(struct btree_iter *iter)
 			break;
 
 		bch2_bkey_buf_unpack(&tmp, c, l->b, k);
-		bch2_btree_node_prefetch(c, iter, tmp.k, iter->btree_id,
-					 iter->level - 1);
+		ret = bch2_btree_node_prefetch(c, iter, tmp.k, iter->btree_id,
+					       iter->level - 1);
 	}
 
 	if (!was_locked)
 		btree_node_unlock(iter, iter->level);
 
 	bch2_bkey_buf_exit(&tmp, c);
+	return ret;
 }
 
 static noinline void btree_node_mem_ptr_set(struct btree_iter *iter,
@@ -1228,7 +1230,7 @@ static __always_inline int btree_iter_down(struct btree_iter *iter,
 		btree_node_mem_ptr_set(iter, level + 1, b);
 
 	if (iter->flags & BTREE_ITER_PREFETCH)
-		btree_iter_prefetch(iter);
+		ret = btree_iter_prefetch(iter);
 
 	if (btree_node_read_locked(iter, level + 1))
 		btree_node_unlock(iter, level + 1);

fs/bcachefs/dirent.c

@@ -210,6 +210,9 @@ int bch2_dirent_rename(struct btree_trans *trans,
 		goto out;
 
 	old_dst = bch2_btree_iter_peek_slot(dst_iter);
+	ret = bkey_err(old_dst);
+	if (ret)
+		goto out;
 
 	if (mode != BCH_RENAME)
 		*dst_inum = le64_to_cpu(bkey_s_c_to_dirent(old_dst).v->d_inum);
@@ -225,6 +228,10 @@ int bch2_dirent_rename(struct btree_trans *trans,
 		goto out;
 
 	old_src = bch2_btree_iter_peek_slot(src_iter);
+	ret = bkey_err(old_src);
+	if (ret)
+		goto out;
+
 	*src_inum = le64_to_cpu(bkey_s_c_to_dirent(old_src).v->d_inum);
 
 	/* Create new dst key: */
@@ -329,20 +336,25 @@ u64 bch2_dirent_lookup(struct bch_fs *c, u64 dir_inum,
 	struct btree_iter *iter;
 	struct bkey_s_c k;
 	u64 inum = 0;
+	int ret = 0;
 
 	bch2_trans_init(&trans, c, 0, 0);
 
 	iter = __bch2_dirent_lookup_trans(&trans, dir_inum,
 					  hash_info, name, 0);
-	if (IS_ERR(iter)) {
-		BUG_ON(PTR_ERR(iter) == -EINTR);
+	ret = PTR_ERR_OR_ZERO(iter);
+	if (ret)
 		goto out;
-	}
 
 	k = bch2_btree_iter_peek_slot(iter);
+	ret = bkey_err(k);
+	if (ret)
+		goto out;
+
 	inum = le64_to_cpu(bkey_s_c_to_dirent(k).v->d_inum);
 	bch2_trans_iter_put(&trans, iter);
 out:
+	BUG_ON(ret == -EINTR);
 	bch2_trans_exit(&trans);
 	return inum;
 }

fs/bcachefs/fs-common.c

@@ -168,6 +168,10 @@ int bch2_unlink_trans(struct btree_trans *trans,
 		goto err;
 
 	k = bch2_btree_iter_peek_slot(dirent_iter);
+	ret = bkey_err(k);
+	if (ret)
+		goto err;
+
 	inum = le64_to_cpu(bkey_s_c_to_dirent(k).v->d_inum);
 
 	inode_iter = bch2_inode_peek(trans, inode_u, inum, BTREE_ITER_INTENT);

fs/bcachefs/fs-io.c

@@ -2668,13 +2668,13 @@ static int __bchfs_fallocate(struct bch_inode_info *inode, int mode,
 		/* already reserved */
 		if (k.k->type == KEY_TYPE_reservation &&
 		    bkey_s_c_to_reservation(k).v->nr_replicas >= replicas) {
-			bch2_btree_iter_next_slot(iter);
+			bch2_btree_iter_advance(iter);
 			continue;
 		}
 
 		if (bkey_extent_is_data(k.k) &&
 		    !(mode & FALLOC_FL_ZERO_RANGE)) {
-			bch2_btree_iter_next_slot(iter);
+			bch2_btree_iter_advance(iter);
 			continue;
 		}
 

fs/bcachefs/inode.c

@@ -519,7 +519,7 @@ struct btree_iter *bch2_inode_create(struct btree_trans *trans,
 		if (k.k->p.snapshot == snapshot &&
 		    k.k->type != KEY_TYPE_inode &&
 		    !bch2_btree_key_cache_find(c, BTREE_ID_inodes, SPOS(0, pos, snapshot))) {
-			bch2_btree_iter_next(iter);
+			bch2_btree_iter_advance(iter);
 			continue;
 		}
 

fs/bcachefs/io.c

@@ -245,8 +245,12 @@ int bch2_sum_sector_overwrites(struct btree_trans *trans,
 			 * writing to, because i_size could be up to one block
 			 * less:
 			 */
-			if (!bkey_cmp(old.k->p, new->k.p))
+			if (!bkey_cmp(old.k->p, new->k.p)) {
 				old = bch2_btree_iter_next(iter);
+				ret = bkey_err(old);
+				if (ret)
+					break;
+			}
 
 			if (old.k && !bkey_err(old) &&
 			    old.k->p.inode == extent_iter->pos.inode &&

fs/bcachefs/move.c

@@ -190,7 +190,7 @@ int bch2_migrate_index_update(struct bch_write_op *op)
 		}
 		atomic_long_inc(&c->extent_migrate_raced);
 		trace_move_race(&new->k);
-		bch2_btree_iter_next_slot(iter);
+		bch2_btree_iter_advance(iter);
 		goto next;
 	}
 out:

fs/bcachefs/reflink.c

@@ -192,8 +192,9 @@ static struct bkey_s_c get_next_src(struct btree_iter *iter, struct bpos end)
 			return k;
 	}
 
-	bch2_btree_iter_set_pos(iter, end);
-	return bkey_s_c_null;
+	if (bkey_cmp(iter->pos, end) >= 0)
+		bch2_btree_iter_set_pos(iter, end);
+	return ret ? bkey_s_c_err(ret) : bkey_s_c_null;
 }
 
 s64 bch2_remap_range(struct bch_fs *c,

fs/bcachefs/str_hash.h

@@ -209,7 +209,7 @@ int bch2_hash_needs_whiteout(struct btree_trans *trans,
 
 	iter = bch2_trans_copy_iter(trans, start);
 
-	bch2_btree_iter_next_slot(iter);
+	bch2_btree_iter_advance(iter);
 
 	for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k, ret) {
 		if (k.k->type != desc.key_type &&

fs/bcachefs/xattr.c

@@ -124,6 +124,7 @@ static int bch2_xattr_get_trans(struct btree_trans *trans, struct bch_inode_info
 	struct bch_hash_info hash = bch2_hash_info_init(trans->c, &inode->ei_inode);
 	struct btree_iter *iter;
 	struct bkey_s_c_xattr xattr;
+	struct bkey_s_c k;
 	int ret;
 
 	iter = bch2_hash_lookup(trans, bch2_xattr_hash_desc, &hash,
@@ -134,7 +135,12 @@ static int bch2_xattr_get_trans(struct btree_trans *trans, struct bch_inode_info
 	if (ret)
 		goto err;
 
-	xattr = bkey_s_c_to_xattr(bch2_btree_iter_peek_slot(iter));
+	k = bch2_btree_iter_peek_slot(iter);
+	ret = bkey_err(k);
+	if (ret)
+		goto err;
+
+	xattr = bkey_s_c_to_xattr(k);
 	ret = le16_to_cpu(xattr.v->x_val_len);
 	if (buffer) {
 		if (ret > size)