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From: Jan Kara <jack@suse.cz>
To: Andreas Dilger <adilger@dilger.ca>
Cc: Jan Kara <jack@suse.cz>,
	linux-fsdevel@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>,
	linux-ext4@vger.kernel.org, xfs@oss.sgi.com,
	Eric Sandeen <sandeen@sandeen.net>,
	Dave Chinner <dchinner@redhat.com>,
	Surbhi Palande <csurbhi@gmail.com>,
	Kamal Mostafa <kamal@canonical.com>,
	Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 1/4] fs: Improve filesystem freezing handling
Date: Thu, 12 Jan 2012 21:07:53 +0100	[thread overview]
Message-ID: <20120112200753.GC8778@quack.suse.cz> (raw)
In-Reply-To: <DB1320A4-7621-44D2-B339-78CB38FAC186@dilger.ca>

On Thu 12-01-12 12:53:35, Andreas Dilger wrote:
> On 2012-01-11, at 6:20 PM, Jan Kara wrote:
> > /**
> > + * sb_start_write - drop write access to a superblock
> > + * @sb: the super we wrote to
> > + *
> > + * Decrement number of writers to the filesystem and wake up possible
> > + * waiters wanting to freeze the filesystem.
> > + */
> > +void sb_end_write(struct super_block *sb)
> > +{
> > +#ifdef CONFIG_SMP
> > +	this_cpu_dec(sb->s_writers);
> > +#else
> > +	preempt_disable();
> > +	sb->s_writers--;
> > +	preempt_enable();
> > +#endif
> > +	/*
> > +	 * Make sure s_writers are updated before we wake up waiters in
> > +	 * freeze_super().
> > +	 */
> > +	smp_mb();
> > +	if (waitqueue_active(&sb->s_writers_wait))
> > +		wake_up(&sb->s_writers_wait);
> > +	rwsem_release(&sb->s_writers_lock_map, 1, _RET_IP_);
> > +}
> 
> Since this function is needed for calling __block_page_mkwrite(), which is
> EXPORT_SYMBOL(), both sb_start_write() and sb_end_write() themselves need
> to be EXPORT_SYMBOL().
  Good point. Fixed. Thanks.

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

WARNING: multiple messages have this Message-ID (diff)
From: Jan Kara <jack@suse.cz>
To: Andreas Dilger <adilger@dilger.ca>
Cc: Jan Kara <jack@suse.cz>, Surbhi Palande <csurbhi@gmail.com>,
	Kamal Mostafa <kamal@canonical.com>,
	Eric Sandeen <sandeen@sandeen.net>,
	LKML <linux-kernel@vger.kernel.org>,
	xfs@oss.sgi.com, Christoph Hellwig <hch@infradead.org>,
	Dave Chinner <dchinner@redhat.com>,
	linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [PATCH 1/4] fs: Improve filesystem freezing handling
Date: Thu, 12 Jan 2012 21:07:53 +0100	[thread overview]
Message-ID: <20120112200753.GC8778@quack.suse.cz> (raw)
In-Reply-To: <DB1320A4-7621-44D2-B339-78CB38FAC186@dilger.ca>

On Thu 12-01-12 12:53:35, Andreas Dilger wrote:
> On 2012-01-11, at 6:20 PM, Jan Kara wrote:
> > /**
> > + * sb_start_write - drop write access to a superblock
> > + * @sb: the super we wrote to
> > + *
> > + * Decrement number of writers to the filesystem and wake up possible
> > + * waiters wanting to freeze the filesystem.
> > + */
> > +void sb_end_write(struct super_block *sb)
> > +{
> > +#ifdef CONFIG_SMP
> > +	this_cpu_dec(sb->s_writers);
> > +#else
> > +	preempt_disable();
> > +	sb->s_writers--;
> > +	preempt_enable();
> > +#endif
> > +	/*
> > +	 * Make sure s_writers are updated before we wake up waiters in
> > +	 * freeze_super().
> > +	 */
> > +	smp_mb();
> > +	if (waitqueue_active(&sb->s_writers_wait))
> > +		wake_up(&sb->s_writers_wait);
> > +	rwsem_release(&sb->s_writers_lock_map, 1, _RET_IP_);
> > +}
> 
> Since this function is needed for calling __block_page_mkwrite(), which is
> EXPORT_SYMBOL(), both sb_start_write() and sb_end_write() themselves need
> to be EXPORT_SYMBOL().
  Good point. Fixed. Thanks.

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

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  reply	other threads:[~2012-01-12 20:07 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-12  1:20 [PATCH 0/4] Fix filesystem freezing Jan Kara
2012-01-12  1:20 ` Jan Kara
2012-01-12  1:20 ` [PATCH 1/4] fs: Improve filesystem freezing handling Jan Kara
2012-01-12  1:20   ` Jan Kara
2012-01-12 19:53   ` Andreas Dilger
2012-01-12 19:53     ` Andreas Dilger
2012-01-12 20:07     ` Jan Kara [this message]
2012-01-12 20:07       ` Jan Kara
2012-01-12 22:57   ` Eric Sandeen
2012-01-12 22:57     ` Eric Sandeen
2012-01-12 23:15     ` Jan Kara
2012-01-12 23:15       ` Jan Kara
2012-01-13  1:26   ` Dave Chinner
2012-01-13  1:26     ` Dave Chinner
2012-01-13 10:12     ` Jan Kara
2012-01-13 10:12       ` Jan Kara
2012-01-12  1:20 ` [PATCH 2/4] vfs: Protect write paths by sb_start_write - sb_end_write Jan Kara
2012-01-12  1:20   ` Jan Kara
2012-01-12 19:56   ` Andreas Dilger
2012-01-12 19:56     ` Andreas Dilger
2012-01-12 20:11     ` Jan Kara
2012-01-12 20:11       ` Jan Kara
2012-01-12  1:20 ` [PATCH 3/4] ext4: Protect ext4_page_mkwrite with " Jan Kara
2012-01-12  1:20   ` Jan Kara
2012-01-12  1:20 ` [PATCH 4/4] xfs: Protect xfs_file_aio_write() " Jan Kara
2012-01-12  1:20   ` Jan Kara
2012-01-12  1:20   ` Jan Kara
2012-01-12 21:29   ` Al Viro
2012-01-12 21:29     ` Al Viro
2012-01-12 21:36     ` Jan Kara
2012-01-12 21:36       ` Jan Kara
2012-01-12  2:48 ` [PATCH 0/4] Fix filesystem freezing Dave Chinner
2012-01-12  2:48   ` Dave Chinner
2012-01-12 11:30   ` Jan Kara
2012-01-12 11:30     ` Jan Kara
2012-01-13  0:09     ` Dave Chinner
2012-01-13  0:09       ` Dave Chinner
2012-01-13 11:07       ` Jan Kara
2012-01-13 11:07         ` Jan Kara
2012-01-12 20:48 ` Ted Ts'o
2012-01-12 20:48   ` Ted Ts'o
2012-01-12 21:38   ` Jan Kara
2012-01-12 21:38     ` Jan Kara

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