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From: Mike Marshall <hubcap@omnibond.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>
Subject: Re: Orangefs ABI documentation
Date: Thu, 11 Feb 2016 18:36:52 -0500	[thread overview]
Message-ID: <CAOg9mSQPODN-tQgB84ds4VmXwj5qUJqkwpJ9Gm2vD4P18zQFUw@mail.gmail.com> (raw)
In-Reply-To: <20160209210657.GH17997@ZenIV.linux.org.uk>

 >  what should the daemon see in such situation?

I agree that it looks like the client-core doesn't notice that a
process doing IO was cancelled. I don't think the client-core
keeps track of what slots are in use, it just trusts that the
buffer-index in any IO upcall is safe to use.  I believe that
wait_for_cancellation_downcall has its roots in the old
AIO code, and ended up at some point getting used
outside of that context.

-Mike





On Tue, Feb 9, 2016 at 4:06 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> On Tue, Feb 09, 2016 at 05:40:49PM +0000, Al Viro wrote:
>
>> Could you try, on top of those fixes, comment the entire
>>         if (op->downcall.type == ORANGEFS_VFS_OP_FILE_IO) {
>>                 long n = wait_for_completion_interruptible_timeout(&op->done,
>>                                                         op_timeout_secs * HZ);
>>                 if (unlikely(n < 0)) {
>>                         gossip_debug(GOSSIP_DEV_DEBUG,
>>                                 "%s: signal on I/O wait, aborting\n",
>>                                 __func__);
>>                 } else if (unlikely(n == 0)) {
>>                         gossip_debug(GOSSIP_DEV_DEBUG,
>>                                 "%s: timed out.\n",
>>                                 __func__);
>>                 }
>>         }
>> in orangefs_devreq_write_iter() out and see if the corruption happens?
>
> Another thing: what's the protocol rules regarding the cancels?  The current
> code looks very odd - if we get a hit by a signal after the daemon has
> picked e.g. read request but before it had replied, we will call
> orangefs_cancel_op_in_progress(), which will call service_operation() with
> ORANGEFS_OP_CANCELLATION which will.  And that'll insert the cancel request
> into list and practically immediately notice that we have a pending signal,
> remove the cancel request from the list and bugger off.  With daemon almost
> certainly *not* getting to see it at all.
>
> I've asked that before if anybody has explained that, I've missed that reply.
> How the fuck is that supposed to work?  Forget the kernel-side implementation
> details, what should the daemon see in such situation?
>
> I would expect something like "you can't reuse a slot until operation has
> been either completed or purged or a cancel had been sent and ACKed by
> the daemon".  Is that what is intended?  If so, the handling of cancels might
> be better off asynchronous - let the slot freeing be done after the cancel
> had been ACKed and _not_ in the context of original syscall...
>
> There are some traces of AIO support in that thing; could this be a victim of
> trimming async parts for submission into the mainline?

  parent reply	other threads:[~2016-02-11 23:36 UTC|newest]

Thread overview: 111+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-15 21:46 Orangefs ABI documentation Mike Marshall
2016-01-22  7:11 ` Al Viro
2016-01-22 11:09   ` Mike Marshall
2016-01-22 16:59     ` Mike Marshall
2016-01-22 17:08       ` Al Viro
2016-01-22 17:40         ` Mike Marshall
2016-01-22 17:43         ` Al Viro
2016-01-22 18:17           ` Mike Marshall
2016-01-22 18:37             ` Al Viro
2016-01-22 19:07               ` Mike Marshall
2016-01-22 19:21                 ` Mike Marshall
2016-01-22 20:04                   ` Al Viro
2016-01-22 20:30                     ` Mike Marshall
2016-01-23  0:12                       ` Al Viro
2016-01-23  1:28                         ` Al Viro
2016-01-23  2:54                           ` Mike Marshall
2016-01-23 19:10                             ` Al Viro
2016-01-23 19:24                               ` Mike Marshall
2016-01-23 21:35                                 ` Mike Marshall
2016-01-23 22:05                                   ` Al Viro
2016-01-23 21:40                                 ` Al Viro
2016-01-23 22:36                                   ` Mike Marshall
2016-01-24  0:16                                     ` Al Viro
2016-01-24  4:05                                       ` Al Viro
2016-01-24 22:12                                         ` Mike Marshall
2016-01-30 17:22                                           ` Al Viro
2016-01-26 19:52                                         ` Martin Brandenburg
2016-01-30 17:34                                           ` Al Viro
2016-01-30 18:27                                             ` Al Viro
2016-02-04 23:30                                               ` Mike Marshall
2016-02-06 19:42                                                 ` Al Viro
2016-02-07  1:38                                                   ` Al Viro
2016-02-07  3:53                                                     ` Al Viro
2016-02-07 20:01                                                       ` [RFC] bufmap-related wait logics (Re: Orangefs ABI documentation) Al Viro
2016-02-08 22:26                                                       ` Orangefs ABI documentation Mike Marshall
2016-02-08 23:35                                                         ` Al Viro
2016-02-09  3:32                                                           ` Al Viro
2016-02-09 14:34                                                             ` Mike Marshall
2016-02-09 17:40                                                               ` Al Viro
2016-02-09 21:06                                                                 ` Al Viro
2016-02-09 22:25                                                                   ` Mike Marshall
2016-02-11 23:36                                                                   ` Mike Marshall [this message]
2016-02-09 22:02                                                                 ` Mike Marshall
2016-02-09 22:16                                                                   ` Al Viro
2016-02-09 22:40                                                                     ` Al Viro
2016-02-09 23:13                                                                       ` Al Viro
2016-02-10 16:44                                                                         ` Al Viro
2016-02-10 21:26                                                                           ` Al Viro
2016-02-11 23:54                                                                           ` Mike Marshall
2016-02-12  0:55                                                                             ` Al Viro
2016-02-12 12:13                                                                               ` Mike Marshall
2016-02-11  0:44                                                                         ` Al Viro
2016-02-11  3:22                                                                           ` Mike Marshall
2016-02-12  4:27                                                                             ` Al Viro
2016-02-12 12:26                                                                               ` Mike Marshall
2016-02-12 18:00                                                                                 ` Martin Brandenburg
2016-02-13 17:18                                                                                   ` Mike Marshall
2016-02-13 17:47                                                                                     ` Al Viro
2016-02-14  2:56                                                                                       ` Al Viro
2016-02-14  3:46                                                                                         ` [RFC] slot allocator - waitqueue use review needed (Re: Orangefs ABI documentation) Al Viro
2016-02-14  4:06                                                                                           ` Al Viro
2016-02-16  2:12                                                                                           ` Al Viro
2016-02-16 19:28                                                                                             ` Al Viro
2016-02-14 22:31                                                                                         ` Orangefs ABI documentation Mike Marshall
2016-02-14 23:43                                                                                           ` Al Viro
2016-02-15 17:46                                                                                             ` Mike Marshall
2016-02-15 18:45                                                                                               ` Al Viro
2016-02-15 22:32                                                                                                 ` Martin Brandenburg
2016-02-15 23:04                                                                                                   ` Al Viro
2016-02-16 23:15                                                                                                     ` Mike Marshall
2016-02-16 23:36                                                                                                       ` Al Viro
2016-02-16 23:54                                                                                                         ` Al Viro
2016-02-17 19:24                                                                                                           ` Mike Marshall
2016-02-17 20:11                                                                                                             ` Al Viro
2016-02-17 21:17                                                                                                               ` Al Viro
2016-02-17 22:24                                                                                                                 ` Mike Marshall
2016-02-17 22:40                                                                                                             ` Martin Brandenburg
2016-02-17 23:09                                                                                                               ` Al Viro
2016-02-17 23:15                                                                                                                 ` Al Viro
2016-02-18  0:04                                                                                                                   ` Al Viro
2016-02-18 11:11                                                                                                                     ` Al Viro
2016-02-18 18:58                                                                                                                       ` Mike Marshall
2016-02-18 19:20                                                                                                                         ` Al Viro
2016-02-18 19:49                                                                                                                         ` Martin Brandenburg
2016-02-18 20:08                                                                                                                           ` Mike Marshall
2016-02-18 20:22                                                                                                                             ` Mike Marshall
2016-02-18 20:38                                                                                                                               ` Mike Marshall
2016-02-18 20:52                                                                                                                                 ` Al Viro
2016-02-18 21:50                                                                                                                                   ` Mike Marshall
2016-02-19  0:25                                                                                                                                     ` Al Viro
2016-02-19 22:11                                                                                                                                       ` Mike Marshall
2016-02-19 22:22                                                                                                                                         ` Al Viro
2016-02-20 12:14                                                                                                                                           ` Mike Marshall
2016-02-20 13:36                                                                                                                                             ` Al Viro
2016-02-22 16:20                                                                                                                                               ` Mike Marshall
2016-02-22 21:22                                                                                                                                                 ` Mike Marshall
2016-02-23 21:58                                                                                                                                                   ` Mike Marshall
2016-02-26 20:21                                                                                                                                                     ` Mike Marshall
2016-02-19 22:32                                                                                                                                         ` Al Viro
2016-02-19 22:45                                                                                                                                           ` Martin Brandenburg
2016-02-19 22:50                                                                                                                                           ` Martin Brandenburg
2016-02-18 20:49                                                                                                                               ` Al Viro
2016-02-15 22:47                                                                                                 ` Mike Marshall
2016-01-23 22:46                                   ` write() semantics (Re: Orangefs ABI documentation) Al Viro
2016-01-23 23:35                                     ` Linus Torvalds
2016-03-03 22:25                                       ` Mike Marshall
2016-03-04 20:55                                         ` Mike Marshall
2016-01-22 20:51                     ` Orangefs ABI documentation Mike Marshall
2016-01-22 23:53                       ` Mike Marshall
2016-01-22 19:54                 ` Al Viro
2016-01-22 19:50             ` Al Viro

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