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From: Al Viro <[email protected]>
To: Jens Axboe <[email protected]>
Cc: [email protected], [email protected]
Subject: Re: [PATCH 03/10] fs: add namei support for doing a non-blocking path lookup
Date: Fri, 27 Dec 2019 00:42:06 +0000	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On Fri, Dec 13, 2019 at 11:36:25AM -0700, Jens Axboe wrote:
> If the fast lookup fails, then return -EAGAIN to have the caller retry
> the path lookup. This is in preparation for supporting non-blocking
> open.

NAK.  We are not littering fs/namei.c with incremental broken bits
and pieces with uncertain eventual use.

And it's broken - lookup_slow() is *NOT* the only place that can and
does block.  For starters, ->d_revalidate() can very well block and
it is called outside of lookup_slow().  So does ->d_automount().
So does ->d_manage().

I'm rather sceptical about the usefulness of non-blocking open, to be
honest, but in any case, one thing that is absolutely not going to
happen is piecewise introduction of such stuff without a discussion
of the entire design.

  reply	other threads:[~2019-12-27  0:42 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-13 18:36 [PATCHSET 0/10] io_uring items for 5.6 Jens Axboe
2019-12-13 18:36 ` [PATCH 01/10] io_uring: add support for fallocate() Jens Axboe
2019-12-13 18:36 ` [PATCH 02/10] io_uring: remove 'sqe' parameter to the OP helpers that take it Jens Axboe
2019-12-13 18:36 ` [PATCH 03/10] fs: add namei support for doing a non-blocking path lookup Jens Axboe
2019-12-27  0:42   ` Al Viro [this message]
2019-12-27  5:05     ` Jens Axboe
2019-12-27  5:25       ` Jens Axboe
2019-12-27 15:45         ` Jens Axboe
2019-12-28 19:03           ` Jens Axboe
2019-12-13 18:36 ` [PATCH 04/10] fs: make build_open_flags() available internally Jens Axboe
2019-12-13 18:36 ` [PATCH 05/10] io_uring: add support for IORING_OP_OPENAT Jens Axboe
2019-12-13 18:36 ` [PATCH 06/10] fs: move filp_close() outside of __close_fd_get_file() Jens Axboe
2019-12-16 19:27   ` Jann Horn
2019-12-16 19:39     ` Jens Axboe
2019-12-13 18:36 ` [PATCH 07/10] io-wq: add support for uncancellable work Jens Axboe
2019-12-13 18:36 ` [PATCH 08/10] io_uring: add support for IORING_OP_CLOSE Jens Axboe
2019-12-13 18:36 ` [PATCH 09/10] io_uring: use u64_to_user_ptr() consistently Jens Axboe
2019-12-13 18:36 ` [PATCH 10/10] io_uring: avoid ring quiesce for fixed file set unregister and update Jens Axboe

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