On 2021/2/10 下午9:19, Christoph Hellwig wrote:
On Tue, Feb 09, 2021 at 05:46:13PM +0800, Ruan Shiyang wrote:
On 2021/2/9 下午5:34, Christoph Hellwig wrote:
On Tue, Feb 09, 2021 at 05:15:13PM +0800, Ruan Shiyang wrote:
The dax dedupe comparison need the iomap_ops pointer as argument, so my
understanding is that we don't modify the argument list of
generic_remap_file_range_prep(), but move its code into
__generic_remap_file_range_prep() whose argument list can be modified to
accepts the iomap_ops pointer. Then it looks like this:
I'd say just add the iomap_ops pointer to
generic_remap_file_range_prep and do away with the extra wrappers. We
only have three callers anyway.
OK.
So looking at this again I think your proposal actaully is better,
given that the iomap variant is still DAX specific. Sorry for
the noise.
Also I think dax_file_range_compare should use iomap_apply instead
of open coding it.
There are two files, which are not reflinked, need to be direct_access()
here. The iomap_apply() can handle one file each time. So, it seems
that iomap_apply() is not suitable for this case...
The pseudo code of this process is as follows:
srclen = ops->begin(&srcmap)
destlen = ops->begin(&destmap)
direct_access(&srcmap, &saddr)
direct_access(&destmap, &daddr)
same = memcpy(saddr, daddr, min(srclen,destlen))
ops->end(&destmap)
ops->end(&srcmap)
I think a nested call like this is necessary. That's why I use the open
code way.
--
Thanks,
Ruan Shiyang.
