From: Al Viro <viro@zeniv.linux.org.uk>
To: Ian Kent <raven@themaw.net>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Howells <dhowells@redhat.com>,
Miklos Szeredi <miklos@szeredi.hu>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/3] vfs: add propagate_mount_tree_busy() helper
Date: Wed, 20 Jul 2022 02:54:24 +0100 [thread overview]
Message-ID: <YtdgUOJlTc4aB+82@ZenIV> (raw)
In-Reply-To: <165751066658.210556.1326573473015621909.stgit@donald.themaw.net>
On Mon, Jul 11, 2022 at 11:37:46AM +0800, Ian Kent wrote:
> +static int do_mount_in_use_check(struct mount *mnt, int cnt)
> +{
> + struct mount *topper;
> +
> + /* Is there exactly one mount on the child that covers
> + * it completely?
> + */
> + topper = find_topper(mnt);
> + if (topper) {
> + int topper_cnt = topper->mnt_mounts_cnt + 1;
> +
> + /* Open file or pwd within singular mount? */
> + if (do_refcount_check(topper, topper_cnt))
> + return 1;
Whatever the hell for? umount(2) will be able to slide the
underlying mount from under the topper, whatever the
refcount of topper might have been.
next prev parent reply other threads:[~2022-07-20 1:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-11 3:37 [PATCH 0/3] autofs: fix may_umount_tree() Ian Kent
2022-07-11 3:37 ` [PATCH 1/3] vfs: track count of child mounts Ian Kent
2022-07-20 1:50 ` Al Viro
2022-07-20 2:17 ` Ian Kent
2022-07-20 7:26 ` Ian Kent
2022-07-26 5:11 ` Ian Kent
2022-07-26 7:10 ` Ian Kent
2022-07-11 3:37 ` [PATCH 2/3] vfs: add propagate_mount_tree_busy() helper Ian Kent
2022-07-20 1:54 ` Al Viro [this message]
2022-07-20 2:31 ` Ian Kent
2022-07-20 2:39 ` Al Viro
2022-07-11 3:37 ` [PATCH 3/3] vfs: make may_umount_tree() mount namespace aware Ian Kent
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