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From: Christoph Hellwig <hch@lst.de>
To: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Al Viro <viro@zeniv.linux.org.uk>,
	"Darrick J. Wong" <djwong@kernel.org>,
	linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-xfs@vger.kernel.org
Subject: Re: [PATCH 5/9] block: introduce holder ops
Date: Wed, 17 May 2023 16:26:09 +0200	[thread overview]
Message-ID: <20230517142609.GA28898@lst.de> (raw)
In-Reply-To: <20230517-holzfiguren-anbot-490e5a7f74fe@brauner>

On Wed, May 17, 2023 at 03:14:40PM +0200, Christian Brauner wrote:
> > Why would we want to pin it?  That just means the device is open and
> > you're have a non-O_PATH mount.
> 
> I think we're talking past each other. Both an O_PATH fd and a regular
> fd would work. But its often desirable to pass a regular fd. If
> userspace uses an O_PATH fd then the block device could be looked up
> later during mounting via blkdev_open().
> 
> But when you use a regular fd blkdev_open() will be called and the
> device resolved right at open time and we'll hold a reference to it.
> 
> So that way userspace can immediately know whether the device can be
> opened/found. That's usually preferable. That's all I meant to say.

I know what you mean.  But based on the concept of how O_PATH and
block devices work it really doesn't make any sense to have a block
device handle for an O_PATH fd, except for the actual fd itself.

  reply	other threads:[~2023-05-17 14:26 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-05 17:51 introduce bdev holder ops and a file system shutdown method Christoph Hellwig
2023-05-05 17:51 ` [PATCH 1/9] block: consolidate the shutdown logic in blk_mark_disk_dead and del_gendisk Christoph Hellwig
2023-05-07 19:08   ` Jan Kara
2023-05-09 13:35     ` Christoph Hellwig
2023-05-05 17:51 ` [PATCH 2/9] block: avoid repeated work in blk_mark_disk_dead Christoph Hellwig
2023-05-07 19:05   ` Jan Kara
2023-05-16 16:29   ` Christian Brauner
2023-05-05 17:51 ` [PATCH 3/9] block: factor out a bd_end_claim helper from blkdev_put Christoph Hellwig
2023-05-07 19:08   ` Jan Kara
2023-05-16 16:29   ` Christian Brauner
2023-05-05 17:51 ` [PATCH 4/9] block: turn bdev_lock into a mutex Christoph Hellwig
2023-05-07 19:09   ` Jan Kara
2023-05-16 16:24   ` Christian Brauner
2023-05-05 17:51 ` [PATCH 5/9] block: introduce holder ops Christoph Hellwig
2023-05-05 18:51   ` Darrick J. Wong
2023-05-09 13:35     ` Christoph Hellwig
2023-05-09 22:19       ` Dave Chinner
2023-05-10  1:38         ` Darrick J. Wong
2023-05-10 15:13         ` Christoph Hellwig
2023-05-07 19:12   ` Jan Kara
2023-05-16 11:02   ` Ming Lei
2023-05-16 14:36     ` Darrick J. Wong
2023-05-17  7:29       ` Christoph Hellwig
2023-05-16 16:00   ` Christian Brauner
2023-05-17  7:30     ` Christoph Hellwig
2023-05-17  7:57       ` Christian Brauner
2023-05-17  8:06         ` Christoph Hellwig
2023-05-17  8:42           ` Christian Brauner
2023-05-17 12:02             ` Christoph Hellwig
2023-05-17 13:14               ` Christian Brauner
2023-05-17 14:26                 ` Christoph Hellwig [this message]
2023-05-18  8:13                   ` Christian Brauner
2023-05-18 13:12                     ` Christoph Hellwig
2023-05-18 13:13                       ` Christoph Hellwig
2023-05-18 13:56                       ` Christian Brauner
2023-05-05 17:51 ` [PATCH 6/9] block: add a mark_dead holder operation Christoph Hellwig
2023-05-05 18:37   ` Darrick J. Wong
2023-05-09 13:30     ` Christoph Hellwig
2023-05-07 19:19   ` Jan Kara
2023-05-09 13:32     ` Christoph Hellwig
2023-05-16 16:17       ` Christian Brauner
2023-05-05 17:51 ` [PATCH 7/9] fs: add a method to shut down the file system Christoph Hellwig
2023-05-05 18:39   ` Darrick J. Wong
2023-05-07 19:20   ` Jan Kara
2023-05-16 16:20   ` Christian Brauner
2023-05-17  7:27     ` Christoph Hellwig
2023-05-05 17:51 ` [PATCH 8/9] xfs: wire up sops->shutdown Christoph Hellwig
2023-05-05 18:23   ` Darrick J. Wong
2023-05-09 13:28     ` Christoph Hellwig
2023-05-05 17:51 ` [PATCH 9/9] xfs: wire up the ->mark_dead holder operation for log and RT devices Christoph Hellwig
2023-05-05 18:32   ` Darrick J. Wong
2023-05-08 15:20 ` introduce bdev holder ops and a file system shutdown method Christoph Hellwig

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