[PATCH 3.12 174/181] btrfs: fix use of uninit "ret" in end_extent_writepage()

Jiri Slaby
2014-06-30T12:30:35Z

From: Eric Sandeen <sandeen@redhat.com>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit 3e2426bd0eb980648449e7a2f5a23e3cd3c7725c upstream.

If this condition in end_extent_writepage() is false:

if (tree->ops && tree->ops->writepage_end_io_hook)

we will then test an uninitialized "ret" at:

ret = ret < 0 ? ret : -EIO;

The test for ret is for the case where ->writepage_end_io_hook
failed, and we'd choose that ret as the error; but if
there is no ->writepage_end_io_hook, nothing sets ret.

Initializing ret to 0 should be sufficient; if
writepage_end_io_hook wasn't set, (!uptodate) means
non-zero err was passed in, so we choose -EIO in that case.

Signed-of-by: Eric Sandeen <sandeen@redhat.com>

Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
fs/btrfs/extent_io.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index a3dd2806d651..b395791dd923 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2312,7 +2312,7 @@ int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
{
int uptodate = (err == 0);
struct extent_io_tree *tree;
- int ret;
+ int ret = 0;

tree = &BTRFS_I(page->mapping->host)->io_tree;

--
2.0.0