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From: "Luis R. Rodriguez" <mcgrof@kernel.org>
To: Jan Kara <jack@suse.cz>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>,
	viro@zeniv.linux.org.uk, bart.vanassche@wdc.com,
	ming.lei@redhat.com, tytso@mit.edu, darrick.wong@oracle.com,
	jikos@kernel.org, rjw@rjwysocki.net, pavel@ucw.cz,
	len.brown@intel.com, linux-fsdevel@vger.kernel.org,
	boris.ostrovsky@oracle.com, jgross@suse.com,
	todd.e.brandt@linux.intel.com, nborisov@suse.com,
	martin.petersen@oracle.com, ONeukum@suse.com,
	oleksandr@natalenko.name, oleg.b.antonyan@gmail.com,
	yu.chen.surf@gmail.com, dan.j.williams@intel.com,
	linux-pm@vger.kernel.org, linux-block@vger.kernel.org,
	linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 03/11] fs: add frozen sb state helpers
Date: Sat, 21 Apr 2018 19:53:52 -0700
Message-ID: <20180422025352.a5vcgdcdatjvxft2@garbanzo.do-not-panic.com> (raw)
In-Reply-To: <20171130171310.GG28180@quack2.suse.cz>

On Thu, Nov 30, 2017 at 06:13:10PM +0100, Jan Kara wrote:
> On Wed 29-11-17 15:23:48, Luis R. Rodriguez wrote:
> > The question of whether or not a superblock is frozen needs to be
> > augmented in the future to account for differences between a user
> > initiated freeze and a kernel initiated freeze done automatically
> > on behalf of the kernel.
> > 
> > Provide helpers so that these can be used instead so that we don't
> > have to expand checks later in these same call sites as we expand
> > the definition of a frozen superblock.
> > 
> > Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
> 
> So helpers are fine but...
> 
> > +/**
> > + * sb_is_frozen_by_user - is superblock frozen by a user call
> > + * @sb: the super to check
> > + *
> > + * Returns true if the super freeze was initiated by userspace, for instance,
> > + * an ioctl call.
> > + */
> > +static inline bool sb_is_frozen_by_user(struct super_block *sb)
> > +{
> > +	return sb->s_writers.frozen == SB_FREEZE_COMPLETE;
> > +}
> 
> ... I dislike the _by_user() suffix as there may be different places that
> call freeze_super() (e.g. device mapper does this during some operations).
> Clearly we need to distinguish "by system suspend" and "the other" cases.
> So please make this clear in the naming.
> 
> In fact, what might be a cleaner solution is to introduce a 'freeze_count'
> for superblock freezing (we already do have this for block devices). Then
> you don't need to differentiate these two cases - but you'd still need to
> properly handle cleanup if freezing of all superblocks fails in the middle.
> So I'm not 100% this works out nicely in the end. But it's certainly worth
> a consideration.

Seems reasonable.

  Luis

  parent reply index

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-29 23:23 [PATCH 00/11] fs: use freeze_fs on suspend/hibernate Luis R. Rodriguez
2017-11-29 23:23 ` [PATCH 01/11] fs: provide unlocked helper for freeze_super() Luis R. Rodriguez
2017-11-30 16:58   ` Jan Kara
2017-11-29 23:23 ` [PATCH 02/11] fs: provide unlocked helper thaw_super() Luis R. Rodriguez
2017-11-30 16:59   ` Jan Kara
2017-11-29 23:23 ` [PATCH 03/11] fs: add frozen sb state helpers Luis R. Rodriguez
2017-11-30 17:13   ` Jan Kara
2017-11-30 19:05     ` Luis R. Rodriguez
2017-12-01 11:47       ` Jan Kara
2017-12-01 21:13         ` Luis R. Rodriguez
2017-12-21 11:03           ` Jan Kara
2018-04-18  0:59             ` Luis R. Rodriguez
2018-04-18 10:12               ` Jan Kara
2018-04-20 18:49               ` Luis R. Rodriguez
2018-04-21 23:53                 ` Jan Kara
2018-04-22  1:22                   ` Luis R. Rodriguez
2018-04-22  2:53     ` Luis R. Rodriguez [this message]
2017-11-29 23:23 ` [PATCH 04/11] fs: distinguish between user initiated freeze and kernel initiated freeze Luis R. Rodriguez
2017-11-29 23:23 ` [PATCH 05/11] fs: add iterate_supers_excl() and iterate_supers_reverse_excl() Luis R. Rodriguez
2017-11-29 23:48   ` Rafael J. Wysocki
2017-11-30  0:22     ` Luis R. Rodriguez
2017-11-30  1:34     ` Dave Chinner
2017-11-30  1:40       ` Rafael J. Wysocki
2017-11-30 16:57   ` Jan Kara
2017-11-29 23:23 ` [PATCH 06/11] fs: freeze on suspend and thaw on resume Luis R. Rodriguez
2017-11-29 23:23 ` [PATCH 07/11] xfs: remove not needed freezing calls Luis R. Rodriguez
2017-11-30 16:21   ` Jan Kara
2017-11-30 20:32     ` Rafael J. Wysocki
2017-11-30 23:30       ` Dave Chinner
2017-11-30 23:40         ` Rafael J. Wysocki
2017-11-29 23:23 ` [PATCH 08/11] ext4: " Luis R. Rodriguez
2017-11-29 23:23 ` [PATCH 09/11] f2fs: " Luis R. Rodriguez
2017-11-29 23:23 ` [PATCH 10/11] nilfs2: " Luis R. Rodriguez
2017-11-29 23:23 ` [PATCH 11/11] jfs: " Luis R. Rodriguez
2017-11-30 16:36 ` [PATCH 00/11] fs: use freeze_fs on suspend/hibernate Yu Chen
2017-11-30 16:41   ` Jiri Kosina
2017-11-30 16:50     ` Yu Chen
2017-12-01 19:05     ` Jeff Layton
2017-12-01 21:51       ` Dave Chinner
2017-11-30 17:01 ` Bart Van Assche
2017-11-30 19:42   ` Luis R. Rodriguez
2017-11-30 20:53     ` Bart Van Assche
2017-11-30 21:03       ` Dave Chinner
2017-11-30 21:51 ` Pavel Machek
2017-12-01  0:44   ` Luis R. Rodriguez
2017-12-13  1:09 ` Rafael J. Wysocki
2017-12-19 16:50   ` Luis R. Rodriguez

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