Re: [Lsf-pc] [LSF/MM TOPIC] async buffered diskio read for userspace apps

[Milosz Tanski <milosz@adfin.com>]

Great, I'll pull into my branch. I'm already using FIO with the cifs
engine to test and help me debug preadv2 changes to smbd and it works
without issues for me today. I'm going to work on the async cifs
engine but that will take longer because I need to expose build the
async SMB2 support into libsmbclient. I'm going to leave that work
till after I get further with preadv2 in samba (hopefully this week).

I think the biggest issue with the changes is the configure part of my
changes (as seen here:
http://git.kernel.dk/?p=fio.git;a=blobdiff;f=configure;h=d4502095250cdf5187b24276c327b727d3d87288;hp=33d1327ebbba5b70a001e422bb5ad9b24d7c7b49;hb=7fd35359259b409ed023b924cb2758e9efb9950c;hpb=5fb4b36674b194ae6c6756314dc0c665fcaea06d
).

The way samba packages the client libraries beyond just smbclient-raw
requiring me to pull in other libraries and then mess with rpath to
guess the distro location is far for ideal. I haven't reported it yet
mostly because I was interested it making progress and making it work.
Ideally samba folks would fix the pkgconfig file for smbclient-raw to
set right LDPATH (including all the depending libraries and rpath) so
that stuff is not needed.

Additionally, there's a few things not exported in the header files
(but used) like:
http://git.kernel.dk/?p=fio.git;a=blob;f=engines/cifs.c;h=67c23fac0c70cfc75932c758f44dd377fc3f2608;hb=7fd35359259b409ed023b924cb2758e9efb9950c#l16
. It looks like lpcfg_resolve_context() is the only way to create a
struct resolve_context which is used in the cliraw hreads, but
lpcfg_resolve_context() is not exported via the header files.

Some of this might be not using the library correctly... there really
wasn't any documentation so I just guessed by looking the torture code
in samba and the smbclient and to see what order to punch the
lpcfg_stuff to make smbcli_full_connection() not fail.

On Tue, Jan 20, 2015 at 2:33 PM, Jens Axboe <axboe@kernel.dk> wrote:
> On 01/19/2015 08:31 AM, Jens Axboe wrote:
>>
>> I didn't look at your code yet, but I'm assuming it's a self contained
>> IO engine. So we should be able to make that work, by only linking the
>> engine itself against libsmbclient. But sheesh, what a pain in the butt,
>> why can't we just all be friends.
>
>
> I pulled it in for testing, and came up with this patch [1]. If you don't do
> anything, it'll build cifs into fio as before. If you add --cifs-external to
> the configure arguments, it'll build cifs.so as an externally loadable
> module. You'd then use:
>
> ioengine=/path/to/cifs.so
>
> to use that module. I did not add an install target, I'll leave that to
> distros...
>
> Let me know how that works for you. And let me know how far along you are
> with the cifs engine, I'd like to pull it in.
>
> http://git.kernel.dk/?p=fio.git;a=shortlog;h=refs/heads/cifs
>
> [1]
> http://git.kernel.dk/?p=fio.git;a=commit;h=c2c05e33b753ae686e24b43d1034d0c474203729
>
> --
> Jens Axboe
>



-- 
Milosz Tanski
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