On 5.07.20 г. 17:20 ч., trix@xxxxxxxxxx wrote:
> From: Tom Rix <trix@xxxxxxxxxx>
>
> clang static analysis flags a garbage return
>
> fs/btrfs/reflink.c:611:2: warning: Undefined or garbage value returned to caller [core.uninitialized.UndefReturn]
> return ret;
> ^~~~~~~~~~
> ret will not be set when olen is 0
> When olen is 0, this function does no work.
>
> So initialize ret to 0
>
> Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
Patch itself is good however, the bug cannot currently be triggered, due
to the following code in the sole caller (btrfs_remap_file_range):
15 if (ret < 0 || len == 0)
14 goto out_unlock;
13
12 if (remap_flags & REMAP_FILE_DEDUP)
11 ret = btrfs_extent_same(src_inode, off, len,
dst_inode, destoff);
10 else
9 ret = btrfs_clone_files(dst_file, src_file, off,
len, destoff);
i.e len is guaranteed to be non-zero
> ---
> fs/btrfs/reflink.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/reflink.c b/fs/btrfs/reflink.c
> index 040009d1cc31..200a80fcbecb 100644
> --- a/fs/btrfs/reflink.c
> +++ b/fs/btrfs/reflink.c
> @@ -572,7 +572,7 @@ static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 len,
> static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
> struct inode *dst, u64 dst_loff)
> {
> - int ret;
> + int ret = 0;
> u64 i, tail_len, chunk_count;
> struct btrfs_root *root_dst = BTRFS_I(dst)->root;
>
>
