Re: [PATCH] xfs: Fix uninitialized variable in xfs_reflink_reserve_cow_range()

[Christoph Hellwig]

On Mon, Oct 17, 2016 at 12:16:44PM +0200, Geert Uytterhoeven wrote:
> with gcc 4.1.2:
> 
>     fs/xfs/xfs_reflink.c: In function âxfs_reflink_reserve_cow_rangeâ:
>     fs/xfs/xfs_reflink.c:327: warning: âerrorâ may be used uninitialized in this function
> 
> Indeed, if "count" is zero, the function will return an uninitialized
> error value.
> 
> While "count" is unlikely to be zero, this function is called through
> the public iomap API. Hence fix this by preinitializing error to zero.

The iomap API should never call in with a zero count, but I think the
initialization is a fine safety net anyway:

Reviewed-by: Christoph Hellwig <hch@xxxxxx>

Btw, what compiler did you get this from?  I haven't seen it, but then
again I recently missed a lot of initializers without compiler warnings,
so either something changed in the Debian stable gcc or our build
system recently..