On 07/11/2016 08:37 PM, Liu Bo wrote:
During build_backref_tree(), if we fail to read a btree node,
we can eventually run into BUG_ON(cache->nr_nodes) that we put
in backref_cache_cleanup(), meaning we have at least one
memory leak.
This frees the backref_node that we allocate at the very beginning of build_backref_tree().
Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
---
fs/btrfs/relocation.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 0477dca..f00267a 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1135,6 +1135,8 @@ out:
btrfs_free_path(path1);
btrfs_free_path(path2);
if (err) {
+ int orig_free = 0;
+
while (!list_empty(&useless)) {
lower = list_entry(useless.next,
struct backref_node, list);
@@ -1171,8 +1173,13 @@ out:
lower = list_entry(useless.next,
struct backref_node, list);
list_del_init(&lower->list);
+ if (lower == node)
+ orig_free = 1;
free_backref_node(cache, lower);
}
+
+ if (!orig_free)
+ free_backref_node(cache, node);
return ERR_PTR(err);
}
ASSERT(!node || !node->detached);
Instead of doing the orig_free set and test
...
if (lower == node)
node = NULL
free_backref_node(cache, lower)
}
free_backref_node(cache, node);
return ERR_PTR(err);
Your patch isn't wrong, but having node NULL after it was free'd makes
us less likely to make mistakes as the code changes.
-chris
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