From: Al Viro <viro@ZenIV.linux.org.uk>
To: Mike Marshall <hubcap@omnibond.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: Orangefs ABI documentation
Date: Fri, 22 Jan 2016 19:50:32 +0000 [thread overview]
Message-ID: <20160122195032.GD17997@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CAOg9mSSL2vtehQd6r-bmxK+zdDdwudJSXMmX2HBscm3cW_sp9A@mail.gmail.com>
On Fri, Jan 22, 2016 at 01:17:40PM -0500, Mike Marshall wrote:
> >> Objections, comments?
>
> I have no objections so far to your suggestions, I'm trying to keep
> my co-workers looking in on this discussion... most other days
> we're all lined up in adjacent cubes...
FWIW, I do see a problem there. This "submitter has given up" flag would
need to be cleared on retries ;-/
When can we end up retrying? We'd need
* wait_for_cancellation_downcall/wait_for_matching_downcall finished
* op_state_serviced(op) false
* op->downcall.status set to -EAGAIN
wait_for_matching_downcall() either returns with op_state_serviced() or
returns one -ETIMEDOUT, -EINTR, -EAGAIN or -EIO, with its return value
ending up in op->downcall.status. So if it was wait_for_matching_downcall(),
we'd have to have returned -EAGAIN. Which can happen only with
op_state_purged(op), i.e. with character device having been closed
after the sucker had been placed on the lists...
wait_for_cancellation_downcall() similar, but it never returns -EAGAIN.
IOW, for it retries are irrelevant.
Damnit, what's the point of picking a purged request from the request
list in orangefs_devreq_read()? Ditto for orangefs_devreq_write_iter()
and request hash...
Note that purge *can't* happen during either of those - ->release() can't
be called while something is in ->read() or ->write_iter(). So if we would
ignore purged requests in those, the problem with retries clearing the
"I gave up" flag wouldn't exist... It's a race anyway - submitter had been
woken up when we'd been marking the request as purged, and it's going to
remove the sucker from whatever list it's on very soon after getting woken
up.
Do you see any problems with skipping such request list/hash elements in
orangefs_devreq_read()/orangefs_devreq_write_iter() resp.?
prev parent reply other threads:[~2016-01-22 19:50 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
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 [this message]
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