On Mon, Jun 4, 2018 at 10:43 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > On Tue, May 29, 2018 at 04:43:01PM +0200, Miklos Szeredi wrote: >> f_op->dedupe_file_range() gets a u64 length to dedup and returns an ssize_t >> actual length deduped. This breaks badly on 32bit archs since the returned >> length will be truncated and possibly overflow into the sign bit (xfs and >> ocfs2 are affected, btrfs limits actual length to 16MiB). > > Can we just make it return 0 vs errno? The only time we return > a different length than the one passed in is due to the btrfs cap. > > Given that this API started out on btrfs we should just do the cap > everywhere to not confuse userspace. And that's a completely arbitrary cap; sure btrfs started out with that, but there's no fundamental reason for that becoming the global limit. Xfs now added a different, larger limit, so based on what reason should that limit be reduced? I don't care either way, but at this stage I'm not going to change this patch, unless there's a very good reason to do so, because if I do someone will come and suggest another improvement, ad-infinitum... Thanks, Miklos
