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From:   David Howells <dhowells@redhat.com>
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To:     "Theodore Y. Ts'o" <tytso@mit.edu>
Cc:     dhowells@redhat.com,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Lutomirski <luto@kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Linux API <linux-api@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Jann Horn <jannh@google.com>
Subject: Re: [PATCH 24/32] vfs: syscall: Add fsopen() to prepare for superblock creation [ver #9]
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Date:   Thu, 12 Jul 2018 23:54:41 +0100
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Theodore Y. Ts'o <tytso@mit.edu> wrote:

> So maybe the answer is that you open /dev/sda1 and /dev/sda2 and then
> pass the file descriptors to the fsopen object?  We can require that
> the fd's be opened with O_RDWR and O_EXCL, which has the benefit where
> if you have multiple block devices, you know *which* block device had
> a problem with being grabbed for an exclusive open.

Would that mean then that doing:

	mount /dev/sda3 /a
	mount /dev/sda3 /b

would then fail on the second command because /dev/sda3 is already open
exclusively?

David