From: Al Viro <viro@ZenIV.linux.org.uk>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: dave@linux.vnet.ibm.com, akpm@linux-foundation.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 7/9] vfs: protect remounting superblock read-only
Date: Fri, 22 Oct 2010 07:46:27 +0100 [thread overview]
Message-ID: <20101022064627.GA21607@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20101005103144.051231469@szeredi.hu>
On Tue, Oct 05, 2010 at 12:31:15PM +0200, Miklos Szeredi wrote:
> From: Miklos Szeredi <mszeredi@suse.cz>
>
> Currently remouting superblock read-only is racy in a major way.
>
> With the per mount read-only infrastructure it is now possible to
> prevent most races, which this patch attempts.
>
> Before starting the remount read-only, set MNT_WRITE_HOLD on all
> mounts so that writes are held off until the remount either succeeds
> or fails.
Umm... What'll happen if your remount will say mnt_want_write() on
e.g. internal vfsmount over that sb? Or, more subtle, tries to
update atime on some opened struct file on that sb.
next prev parent reply other threads:[~2010-10-22 6:46 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-05 10:31 [PATCH 0/9] read-only remount fixes Miklos Szeredi
2010-10-05 10:31 ` [PATCH 1/9] vfs: fix infinite loop caused by clone_mnt race Miklos Szeredi
2010-10-05 10:49 ` Miklos Szeredi
2010-10-05 10:31 ` [PATCH 2/9] vfs: ignore error on forced remount Miklos Szeredi
2010-10-05 10:31 ` [PATCH 3/9] vfs: fix per mount read-write Miklos Szeredi
2010-10-05 10:31 ` [PATCH 4/9] vfs: add sb_force_remount_readonly() helper Miklos Szeredi
2010-10-05 10:31 ` [PATCH 5/9] vfs: allow mnt_want_write() to sleep Miklos Szeredi
2010-10-05 10:31 ` [PATCH 6/9] vfs: keep list of mounts for each superblock Miklos Szeredi
2010-10-05 10:31 ` [PATCH 7/9] vfs: protect remounting superblock read-only Miklos Szeredi
2010-10-22 6:46 ` Al Viro [this message]
2010-10-22 12:25 ` Miklos Szeredi
2010-10-22 16:10 ` Miklos Szeredi
2010-10-22 16:14 ` [PATCH 7/9 updated] " Miklos Szeredi
2010-10-23 16:19 ` Al Viro
2010-10-23 19:35 ` Miklos Szeredi
2010-10-23 21:42 ` Al Viro
2010-10-25 12:36 ` Miklos Szeredi
2010-10-05 10:31 ` [PATCH 8/9] vfs: fs_may_remount_ro: turn unnecessary check into a WARN_ON Miklos Szeredi
2010-10-05 10:31 ` [PATCH 9/9] vfs: mark mounts read-only on forced remount Miklos Szeredi
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