From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Jan Kara <jack@suse.cz>
Cc: Linux PM list <linux-pm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, Dave Chinner <david@fromorbit.com>,
Nigel Cunningham <nigel@tuxonice.net>,
Pavel Machek <pavel@ucw.cz>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [RFC][PATCH] PM / Sleep: Freeze filesystems during system suspend/hibernation
Date: Mon, 30 Jan 2012 22:05:33 +0100 [thread overview]
Message-ID: <201201302205.34159.rjw@sisk.pl> (raw)
In-Reply-To: <20120130200040.GB7827@quack.suse.cz>
On Monday, January 30, 2012, Jan Kara wrote:
> On Sat 28-01-12 14:45:49, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rjw@sisk.pl>
> >
> > Freeze all filesystems during system suspend and (kernel-driven)
> > hibernation by calling freeze_supers() for all superblocks and thaw
> > them during the subsequent resume with the help of thaw_supers().
> >
> > This makes filesystems stay in a consistent state in case something
> > goes wrong between system suspend (or hibernation) and the subsequent
> > resume (e.g. journal replays won't be necessary in those cases). In
> > particular, this should help to solve a long-standing issue that, in
> > some cases, during resume from hibernation the boot loader causes the
> > journal to be replied for the filesystem containing the kernel image
> > and/or initrd causing it to become inconsistent with the information
> > stored in the hibernation image.
> >
> > The user-space-driven hibernation (s2disk) is not covered by this
> > change, because the freezing of filesystems prevents s2disk from
> > accessing device special files it needs to do its job.
> >
> > This change is based on earlier work by Nigel Cunningham.
> >
> > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> > ---
> > fs/super.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++
> > include/linux/fs.h | 3 +
> > kernel/power/hibernate.c | 11 +++++--
> > kernel/power/power.h | 23 --------------
> > kernel/power/suspend.c | 42 +++++++++++++++++++++++++++
> > 5 files changed, 128 insertions(+), 24 deletions(-)
> >
> > Index: linux/fs/super.c
> > ===================================================================
> > --- linux.orig/fs/super.c
> > +++ linux/fs/super.c
> > @@ -594,6 +594,79 @@ void iterate_supers_type(struct file_sys
> > EXPORT_SYMBOL(iterate_supers_type);
> >
> > /**
> > + * thaw_supers - call thaw_super() for all superblocks
> > + */
> > +void thaw_supers(void)
> > +{
> > + struct super_block *sb, *p = NULL;
> > +
> > + spin_lock(&sb_lock);
> > + list_for_each_entry(sb, &super_blocks, s_list) {
> > + if (list_empty(&sb->s_instances))
> > + continue;
> > + sb->s_count++;
> > + spin_unlock(&sb_lock);
> > +
> > + if (sb->s_flags & MS_FROZEN) {
> > + thaw_super(sb);
> > + sb->s_flags &= ~MS_FROZEN;
> > + }
> > +
> > + spin_lock(&sb_lock);
> > + if (p)
> > + __put_super(p);
> > + p = sb;
> > + }
> > + if (p)
> > + __put_super(p);
> > + spin_unlock(&sb_lock);
> > +}
> At least for thawing you can use iterate_supers() helper.
OK
> > +/**
> > + * freeze_supers - call freeze_super() for all superblocks
> > + */
> > +int freeze_supers(void)
> > +{
> > + struct super_block *sb, *p = NULL;
> > + int error = 0;
> > +
> > + spin_lock(&sb_lock);
> > + /*
> > + * Freeze in reverse order so filesystems depending on others are
> > + * frozen in the right order (eg. loopback on ext3).
> > + */
> Ho, hum, are you sure the order in super_blocks list is the one you need?
> Maybe it is but I'm not sure you are guaranteed it is.
Well, is there any way I can get the right order?
> I've added Al to CC,
> he'll likely have opinion on this...
>
> > + list_for_each_entry_reverse(sb, &super_blocks, s_list) {
> > + if (list_empty(&sb->s_instances))
> > + continue;
> > + sb->s_count++;
> > + spin_unlock(&sb_lock);
> > +
> > + if (sb->s_root && sb->s_frozen != SB_FREEZE_TRANS
> > + && !(sb->s_flags & MS_RDONLY)) {
> > + error = freeze_super(sb);
> > + if (!error)
> > + sb->s_flags |= MS_FROZEN;
> > + }
> > +
> > + spin_lock(&sb_lock);
> > + if (error)
> > + break;
> > + if (p)
> > + __put_super(p);
> > + p = sb;
> > + }
> > + if (p)
> > + __put_super(p);
> > + spin_unlock(&sb_lock);
> > +
> > + if (error)
> > + thaw_supers();
> > +
> > + return error;
> > +}
> > +
> > +
> > +/**
> > * get_super - get the superblock of a device
> > * @bdev: device to get the superblock for
> > *
Thanks,
Rafael
next prev parent reply other threads:[~2012-01-30 21:01 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-28 13:45 [RFC][PATCH] PM / Sleep: Freeze filesystems during system suspend/hibernation Rafael J. Wysocki
2012-01-28 21:23 ` Nigel Cunningham
2012-01-29 15:55 ` Martin Steigerwald
2012-01-29 19:53 ` Rafael J. Wysocki
2012-01-29 16:28 ` Srivatsa S. Bhat
2012-01-29 19:53 ` Rafael J. Wysocki
2012-01-30 23:24 ` Srivatsa S. Bhat
2012-01-30 20:00 ` Jan Kara
2012-01-30 21:05 ` Rafael J. Wysocki [this message]
2012-01-30 21:10 ` Nigel Cunningham
2012-01-31 0:03 ` Jan Kara
2012-01-30 23:58 ` Jan Kara
2012-02-01 13:36 ` Pavel Machek
2012-02-01 15:29 ` Alan Stern
2012-02-10 2:52 ` Jamie Lokier
2012-02-10 9:03 ` Jan Kara
2012-02-02 3:17 ` Nigel Cunningham
2012-02-17 15:41 ` Josh Boyer
2012-02-17 18:33 ` Josh Boyer
2012-02-17 20:59 ` Rafael J. Wysocki
2012-05-25 16:55 ` Josh Boyer
2012-05-25 19:13 ` Rafael J. Wysocki
2013-12-17 16:03 ` Josh Boyer
2013-12-17 16:04 ` Josh Boyer
2013-12-17 23:08 ` Pavel Machek
2013-12-17 23:31 ` Dave Chinner
2013-12-18 0:01 ` Pavel Machek
2013-12-18 12:39 ` Dave Chinner
2013-12-18 14:08 ` Pavel Machek
2013-12-19 0:22 ` Dave Chinner
2013-12-21 23:33 ` Pavel Machek
2013-12-23 3:48 ` Dave Chinner
2013-12-18 0:52 ` Rafael J. Wysocki
2013-12-18 1:00 ` Josh Boyer
2013-12-18 1:16 ` Rafael J. Wysocki
2013-12-18 12:31 ` Josh Boyer
2013-12-18 21:40 ` Rafael J. Wysocki
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=201201302205.34159.rjw@sisk.pl \
--to=rjw@sisk.pl \
--cc=david@fromorbit.com \
--cc=jack@suse.cz \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=nigel@tuxonice.net \
--cc=pavel@ucw.cz \
--cc=srivatsa.bhat@linux.vnet.ibm.com \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).