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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH 3/4] fs: expose LOOKUP_NONBLOCK through openat2() RESOLVE_NONBLOCK
Date: Tue, 15 Dec 2020 14:31:47 -0800	[thread overview]
Message-ID: <CAHk-=whAhRQaFUn7dhDAgoofVRA2EJvbmiKAYFA0ciwPQjnGwg@mail.gmail.com> (raw)
In-Reply-To: <20201215222522.GS3913616@dread.disaster.area>

On Tue, Dec 15, 2020 at 2:25 PM Dave Chinner <david@fromorbit.com> wrote:
>
> What text are you going to add to the man page to describe how this
> flag behaves to developers?

I think it was you or Jens who suggested renaming it to RESOLVE_CACHED
(and LOOKUP_CACHED), and I think that would be a good idea.

Make it explicit that this isn't primarily about avoiding blocking,
but about only doing name lookups that can be resolved directly from
the dcache.

Even in some other contexts, the traditional NONBLOCK naming isn't
necessarily about not blocking. Lots of operations tend to block even
for things that are requested to be "nonblocking", and in fact they
can even cause IO (ie a "nonblocking" read can and will cause IO when
it copies to user space, because _that_ part isn't nonblocking).

        Linus

  reply	other threads:[~2020-12-15 22:33 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-14 19:13 [PATCHSET v3 0/4] fs: Support for LOOKUP_NONBLOCK / RESOLVE_NONBLOCK Jens Axboe
2020-12-14 19:13 ` [PATCH 1/4] fs: make unlazy_walk() error handling consistent Jens Axboe
2020-12-14 19:13 ` [PATCH 2/4] fs: add support for LOOKUP_NONBLOCK Jens Axboe
2020-12-15 12:24   ` Matthew Wilcox
2020-12-15 15:29     ` Jens Axboe
2020-12-15 15:33       ` Matthew Wilcox
2020-12-15 15:37         ` Jens Axboe
2020-12-15 16:08           ` Jens Axboe
2020-12-15 16:14             ` Jens Axboe
2020-12-15 18:29             ` Linus Torvalds
2020-12-15 18:44               ` Jens Axboe
2020-12-15 18:47                 ` Linus Torvalds
2020-12-15 19:03                   ` Jens Axboe
2020-12-15 19:32                     ` Linus Torvalds
2020-12-15 19:38                       ` Jens Axboe
2020-12-16  2:36   ` Al Viro
2020-12-16  3:30     ` Jens Axboe
2020-12-16  2:43   ` Al Viro
2020-12-16  3:32     ` Jens Axboe
2020-12-14 19:13 ` [PATCH 3/4] fs: expose LOOKUP_NONBLOCK through openat2() RESOLVE_NONBLOCK Jens Axboe
2020-12-15 22:25   ` Dave Chinner
2020-12-15 22:31     ` Linus Torvalds [this message]
2020-12-15 23:25       ` Jens Axboe
2020-12-16  2:37   ` Al Viro
2020-12-16  3:39     ` Linus Torvalds
2020-12-14 19:13 ` [PATCH 4/4] io_uring: enable LOOKUP_NONBLOCK path resolution for filename lookups Jens Axboe
2020-12-15  3:06 ` [PATCHSET v3 0/4] fs: Support for LOOKUP_NONBLOCK / RESOLVE_NONBLOCK Linus Torvalds
2020-12-15  3:18   ` Jens Axboe
2020-12-15  6:11 ` Al Viro
2020-12-15 15:29   ` Jens Axboe
2021-01-04  5:31 ` Al Viro
2021-01-04 14:43   ` Jens Axboe
2021-01-04 16:54     ` Al Viro
2021-01-04 17:03       ` Jens Axboe
     [not found] ` <m1lfbrwrgq.fsf@fess.ebiederm.org>
2021-02-14 16:38   ` [PATCHSET v3 0/4] fs: Support for LOOKUP_NONBLOCK / RESOLVE_NONBLOCK (Insufficiently faking current?) Jens Axboe
2021-02-14 20:30     ` Linus Torvalds
2021-02-14 21:24       ` Al Viro
2021-02-15 18:07       ` Eric W. Biederman
2021-02-15 18:24         ` Jens Axboe
2021-02-15 21:09           ` Jens Axboe
2021-02-15 22:41             ` Eric W. Biederman
2021-02-16  2:41               ` Jens Axboe
2021-02-17  1:18                 ` Jens Axboe
2021-02-17  1:26                   ` Jens Axboe
2021-02-17  3:11                     ` Jens Axboe
2021-02-15 17:56     ` Eric W. Biederman

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