[PATCH -next] btrfs: Fix type conversion in btrfs_read_root_item

YueHaibing
2019-02-20T02:55:14Z

btrfs_item_size_nr return value is u32, convert it to int may result
in truncation.Also read_extent_buffer expect a unsigned param, so
min_t should use type u32 to compare.

Fixes: 8ea05e3a4262 ("Btrfs: introduce subvol uuids and times")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
---
fs/btrfs/root-tree.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 02d1a57af78b..893d12fbfda0 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -21,12 +21,12 @@ static void btrfs_read_root_item(struct extent_buffer *eb, int slot,
struct btrfs_root_item *item)
{
uuid_le uuid;
- int len;
+ u32 len;
int need_reset = 0;

len = btrfs_item_size_nr(eb, slot);
read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
- min_t(int, len, (int)sizeof(*item)));
+ min_t(u32, len, sizeof(*item)));
if (len < sizeof(*item))
need_reset = 1;
if (!need_reset && btrfs_root_generation(item)