From: Linus Torvalds <torvalds@linux-foundation.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
io-uring <io-uring@vger.kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>
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: <20210125213614.24001-1-axboe@kernel.dk>
On Mon, Jan 25, 2021 at 1:36 PM Jens Axboe <axboe@kernel.dk> 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
next prev 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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