From: Colin Walters <walters@verbum.org>
To: Colin Walters <walters@verbum.org>, "Theodore Ts'o" <tytso@mit.edu>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>,
xfs <linux-xfs@vger.kernel.org>,
"linux-fsdevel" <linux-fsdevel@vger.kernel.org>,
"linux-ext4" <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH] vfs: freeze filesystems just prior to reboot
Date: Fri, 19 May 2017 12:48:41 -0400 [thread overview]
Message-ID: <1495212521.1935005.982278280.1453433F@webmail.messagingengine.com> (raw)
In-Reply-To: <1495211669.1931975.982263184.0F641F32@webmail.messagingengine.com>
On Fri, May 19, 2017, at 12:34 PM, Colin Walters wrote:
>
> So as far as I can see, a userspace API to ensure the journal is
> flushed on a mounted filesystem is going to be necessary for
> the general case. I don't have a strong opinion on whether or not
> that's `syncfs()` - if it's e.g. a `XFS_IOC_FREEZE` `_THAW` pair
> that seems OK to me too.
Or (thinking about this more) maybe we indeed could implement that today by pivoting back to
the initramfs, and using umount()+mount() as our "syncfs() + journal flush" implementation.
Basically when we have to update /boot, we unmount, then remount again and add
new kernel+initramfs, unmount, remount and mv(/boot/grub2.conf.new,/boot/grub2.conf),
then finally unmount again.
In current design this would require keeping the initramfs resident in memory
just for this purpose, or to re-synthesize it on shutdown.
Not impossible, but it'd sure be simpler if say syncfs() had a flags argument
and there were a special "flush the journal" argument for this.
next prev parent reply other threads:[~2017-05-19 16:48 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-19 0:20 [PATCH] vfs: freeze filesystems just prior to reboot Darrick J. Wong
2017-05-19 8:29 ` Amir Goldstein
2017-05-19 18:58 ` Darrick J. Wong
2017-05-19 14:00 ` Colin Walters
2017-05-19 15:27 ` Theodore Ts'o
2017-05-19 16:34 ` Colin Walters
2017-05-19 16:48 ` Colin Walters [this message]
2017-05-19 18:20 ` Theodore Ts'o
2017-05-19 19:41 ` Darrick J. Wong
2017-05-23 11:10 ` Jan Kara
2017-05-19 19:01 ` Darrick J. Wong
2017-08-03 20:24 ` Colin Walters
2017-08-05 14:16 ` Christoph Hellwig
2017-08-05 15:45 ` Darrick J. Wong
2017-08-11 10:02 ` Christoph Hellwig
2017-08-11 16:26 ` Darrick J. Wong
2017-08-11 16:27 ` Christoph Hellwig
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