From: Jens Axboe <axboe@kernel.dk>
To: Matthew Wilcox <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 1/2] fs: add support for LOOKUP_NONBLOCK
Date: Fri, 11 Dec 2020 11:55:46 -0700 [thread overview]
Message-ID: <b496fc38-908b-d3e7-4506-f0b0d6f7b60c@kernel.dk> (raw)
In-Reply-To: <20201211173305.GB2443@casper.infradead.org>
On 12/11/20 10:33 AM, Matthew Wilcox wrote:
> On Fri, Dec 11, 2020 at 09:05:26AM -0700, Jens Axboe wrote:
>> On 12/10/20 7:45 PM, Al Viro wrote:
>>> So how hard are your "we don't want to block here" requirements? Because
>>> the stuff you do after complete_walk() can easily be much longer than
>>> everything else.
>>
>> Ideally it'd extend a bit beyond the RCU lookup, as things like proc
>> resolution will still fail with the proposed patch. But that's not a
>> huge deal to me, I consider the dentry lookup to be Good Enough.
>
> FWIW, /proc/$pid always falls back to REF walks. Here's a patch from
> one of my colleagues that aims to fix that.
>
> https://lore.kernel.org/linux-fsdevel/20201204000212.773032-1-stephen.s.brennan@oracle.com/
>
> Maybe you had one of the other parts of /proc in mind?
Yes, it is/was /proc/self/ specifically, which the patch won't really
help. But it's not like it's a huge issue, and I'm quite happy (for
now) to just have that -EOPNOTSUPP on open as it does.
--
Jens Axboe
next prev parent reply other threads:[~2020-12-11 20:41 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-10 20:01 [PATCHSET 0/2] fs: Support for LOOKUP_NONBLOCK / RESOLVE_NONBLOCK Jens Axboe
2020-12-10 20:01 ` [PATCH 1/2] fs: add support for LOOKUP_NONBLOCK Jens Axboe
2020-12-10 20:53 ` Linus Torvalds
2020-12-10 21:06 ` Jens Axboe
2020-12-11 2:45 ` Al Viro
2020-12-11 16:05 ` Jens Axboe
2020-12-11 17:20 ` Al Viro
2020-12-11 17:35 ` Linus Torvalds
2020-12-11 18:50 ` Jens Axboe
2020-12-11 21:51 ` Al Viro
2020-12-11 23:47 ` Jens Axboe
2020-12-11 17:33 ` Matthew Wilcox
2020-12-11 18:55 ` Jens Axboe [this message]
2020-12-11 2:35 ` Al Viro
2020-12-11 15:57 ` Jens Axboe
2020-12-11 17:21 ` Linus Torvalds
2020-12-11 17:29 ` Al Viro
2020-12-11 17:38 ` Al Viro
2020-12-11 17:44 ` Linus Torvalds
2020-12-11 21:46 ` Jens Axboe
2020-12-10 20:01 ` [PATCH 2/2] fs: expose LOOKUP_NONBLOCK through openat2() RESOLVE_NONBLOCK Jens Axboe
2020-12-10 22:29 ` Dave Chinner
2020-12-10 23:12 ` Jens Axboe
2020-12-10 23:29 ` Linus Torvalds
2020-12-11 0:58 ` Dave Chinner
2020-12-11 1:01 ` Linus Torvalds
2020-12-11 3:45 ` Dave Chinner
2020-12-11 18:07 ` Linus Torvalds
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