Btrfs: kill some BUG_ONs() in the find_parent_nodes()

The reason that BUG_ON() happens in these places is just
because of ENOMEM.

We try ro return ENOMEM rather than trigger BUG_ON(), the
caller will abort the transaction thus avoiding the kernel panic.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index bd605c87adfd..3dd0693bad78 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -900,7 +900,8 @@ again:
                 if (ref->count && ref->root_id && ref->parent == 0) {
                         /* no parent == root of tree */
                         ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
-                        BUG_ON(ret < 0);
+                        if (ret < 0)
+                                goto out;
                 }
                 if (ref->count && ref->parent) {
                         struct extent_inode_elem *eie = NULL;
@@ -920,6 +921,8 @@ again:
                         ret = ulist_add_merge(refs, ref->parent,
                                               (uintptr_t)ref->inode_list,
                                               (u64 *)&eie, GFP_NOFS);
+                        if (ret < 0)
+                                goto out;
                         if (!ret && extent_item_pos) {
                                 /*
                                  * we've recorded that parent, so we must extend
@@ -930,7 +933,6 @@ again:
                                         eie = eie->next;
                                 eie->next = ref->inode_list;
                         }
-                        BUG_ON(ret < 0);
                 }
                 kfree(ref);
         }