On 2019/2/20 14:10, Dan Carpenter wrote: > On Wed, Feb 20, 2019 at 08:58:43AM +0300, Dan Carpenter wrote: >> On Wed, Feb 20, 2019 at 03:08:40AM +0000, YueHaibing wrote: >>> 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 <yuehaib...@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))); >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >> Yeah, min_t() should normally cast to unsigned and the extra cast is >> silly. >> > > Btw, I shouldn't have had to dig through the patch to find the *real* > reason you wrote it. A better description would have said: > > There is a messy cast here: > > min_t(int, len, (int)sizeof(*item))); > > min_t() should normally cast to unsigned. It's not possible for > "len" to be negative, but if it were then then we definitely > wouldn't want to pass negatives to read_extent_buffer(). Also there > is an extra cast. > > This patch shouldn't affect runtime, it's just a clean up.
Yes, This just a cleanup, Thanks! > > regards, > dan carpenter > > > . >