Btrfs: fix memory leaks on walking backrefs failure

[platform/adaptation/renesas_rcar/renesas_kernel.git] / fs / btrfs / backref.c

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 1538496..aded3ef 100644 (file)
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -66,6 +66,16 @@ static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
        return 0;
 }
 
+static void free_inode_elem_list(struct extent_inode_elem *eie)
+{
+       struct extent_inode_elem *eie_next;
+
+       for (; eie; eie = eie_next) {
+               eie_next = eie->next;
+               kfree(eie);
+       }
+}
+
 static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte,
                                u64 extent_item_pos,
                                struct extent_inode_elem **eie)
@@ -275,6 +285,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
                                        old = old->next;
                                old->next = eie;
                        }
+                       eie = NULL;
                }
 next:
                ret = btrfs_next_old_item(root, path, time_seq);
@@ -282,6 +293,8 @@ next:
 
        if (ret > 0)
                ret = 0;
+       else if (ret < 0)
+               free_inode_elem_list(eie);
        return ret;
 }
 
@@ -301,23 +314,34 @@ static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
        int ret = 0;
        int root_level;
        int level = ref->level;
+       int index;
 
        root_key.objectid = ref->root_id;
        root_key.type = BTRFS_ROOT_ITEM_KEY;
        root_key.offset = (u64)-1;
+
+       index = srcu_read_lock(&fs_info->subvol_srcu);
+
        root = btrfs_read_fs_root_no_name(fs_info, &root_key);
        if (IS_ERR(root)) {
+               srcu_read_unlock(&fs_info->subvol_srcu, index);
                ret = PTR_ERR(root);
                goto out;
        }
 
        root_level = btrfs_old_root_level(root, time_seq);
 
-       if (root_level + 1 == level)
+       if (root_level + 1 == level) {
+               srcu_read_unlock(&fs_info->subvol_srcu, index);
                goto out;
+       }
 
        path->lowest_level = level;
        ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq);
+
+       /* root node has been locked, we can release @subvol_srcu safely here */
+       srcu_read_unlock(&fs_info->subvol_srcu, index);
+
        pr_debug("search slot in root %llu (level %d, ref count %d) returned "
                 "%d for key (%llu %u %llu)\n",
                 ref->root_id, level, ref->count, ret,
@@ -377,10 +401,16 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
                        continue;
                err = __resolve_indirect_ref(fs_info, path, time_seq, ref,
                                             parents, extent_item_pos);
-               if (err == -ENOMEM)
-                       goto out;
-               if (err)
+               /*
+                * we can only tolerate ENOENT,otherwise,we should catch error
+                * and return directly.
+                */
+               if (err == -ENOENT) {
                        continue;
+               } else if (err) {
+                       ret = err;
+                       goto out;
+               }
 
                /* we put the first parent into the ref at hand */
                ULIST_ITER_INIT(&uiter);
@@ -828,6 +858,7 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
        struct list_head prefs_delayed;
        struct list_head prefs;
        struct __prelim_ref *ref;
+       struct extent_inode_elem *eie = NULL;
 
        INIT_LIST_HEAD(&prefs);
        INIT_LIST_HEAD(&prefs_delayed);
@@ -941,7 +972,6 @@ again:
                                goto out;
                }
                if (ref->count && ref->parent) {
-                       struct extent_inode_elem *eie = NULL;
                        if (extent_item_pos && !ref->inode_list) {
                                u32 bsz;
                                struct extent_buffer *eb;
@@ -976,6 +1006,7 @@ again:
                                        eie = eie->next;
                                eie->next = ref->inode_list;
                        }
+                       eie = NULL;
                }
                list_del(&ref->list);
                kmem_cache_free(btrfs_prelim_ref_cache, ref);
@@ -994,7 +1025,8 @@ out:
                list_del(&ref->list);
                kmem_cache_free(btrfs_prelim_ref_cache, ref);
        }
-
+       if (ret < 0)
+               free_inode_elem_list(eie);
        return ret;
 }
 
@@ -1002,7 +1034,6 @@ static void free_leaf_list(struct ulist *blocks)
 {
        struct ulist_node *node = NULL;
        struct extent_inode_elem *eie;
-       struct extent_inode_elem *eie_next;
        struct ulist_iterator uiter;
 
        ULIST_ITER_INIT(&uiter);
@@ -1010,10 +1041,7 @@ static void free_leaf_list(struct ulist *blocks)
                if (!node->aux)
                        continue;
                eie = (struct extent_inode_elem *)(uintptr_t)node->aux;
-               for (; eie; eie = eie_next) {
-                       eie_next = eie->next;
-                       kfree(eie);
-               }
+               free_inode_elem_list(eie);
                node->aux = 0;
        }
 
@@ -1101,6 +1129,7 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
                if (!node)
                        break;
                bytenr = node->val;
+               cond_resched();
        }
 
        ulist_free(tmp);