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From: Linus Torvalds <[email protected]>
To: Jens Axboe <[email protected]>
Cc: linux-fsdevel <[email protected]>,
	io-uring <[email protected]>,
	Al Viro <[email protected]>
Subject: Re: [PATCHSET RFC] support RESOLVE_CACHED for statx
Date: Mon, 25 Jan 2021 15:39:40 -0800	[thread overview]
Message-ID: <CAHk-=whh=+nkoZFqb1zztY9kUo-Ua75+zY16HeU_3j1RV4JR0Q@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>

On Mon, Jan 25, 2021 at 1:36 PM Jens Axboe <[email protected]> wrote:
>
>     Patch 2 is the
> mostly ugly part, but not sure how we can do this any better - we need
> to ensure that any sort of revalidation or sync in ->getattr() honors
> it too.

Yeah, that's not pretty, but I agree - it looks like this just
requires the filesystem to check whether it needs to revalidate or
not.

But I think that patch could do better than what your patch does. Some
of them are "filesystems could decide to be more finegrained") -  your
cifs patch comes to mind - but some of your "return -EAGAIN if cached"
seem to be just plain pointless.

In afs, for example, you return -EAGAIN instead of just doing the
read-seqlock thing. That's a really cheap CPU-only operation. We're
talking "cheaper than a spinlock" sequence.

           Linus

  parent reply	other threads:[~2021-01-25 23:43 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-25 21:36 [PATCHSET RFC] support RESOLVE_CACHED for statx Jens Axboe
2021-01-25 21:36 ` [PATCH 1/3] fs: add support for AT_STATX_CACHED Jens Axboe
2021-01-25 21:36 ` [PATCH 2/3] fs: ensure that ->getattr() honors AT_STATX_CACHED Jens Axboe
2021-01-25 21:36 ` [PATCH 3/3] io_uring: use AT_STATX_CACHED for IORING_OP_STATX fast path Jens Axboe
2021-01-25 23:39 ` Linus Torvalds [this message]
2021-01-26  1:06   ` [PATCHSET RFC] support RESOLVE_CACHED for statx Jens Axboe
2021-01-26  1:28     ` Linus Torvalds
2021-01-26  1:31       ` Jens Axboe

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