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From: Dave Chinner <david@fromorbit.com>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org, 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>,
	LKML <linux-kernel@vger.kernel.org>,
	xfs@oss.sgi.com, linux-ext4@vger.kernel.org
Subject: Re: [PATCH 2/8] vfs: Protect write paths by sb_start_write - sb_end_write
Date: Tue, 24 Jan 2012 19:21:19 +1100	[thread overview]
Message-ID: <20120124082119.GO15102@dastard> (raw)
In-Reply-To: <1327091686-23177-3-git-send-email-jack@suse.cz>

On Fri, Jan 20, 2012 at 09:34:40PM +0100, Jan Kara wrote:
> There are three entry points which dirty pages in a filesystem.  mmap (handled
> by block_page_mkwrite()), buffered write (handled by
> __generic_file_aio_write()), and truncate (it can dirty last partial page -
> handled inside each filesystem separately). Protect these places with
> sb_start_write() and sb_end_write().

fallocate can also dirty pages, either during preallocation or hole
punching.  Hence if you are going to promote truncate to
SB_FREEZE_WRITE protection then you need to promote everything else
that can zero partial blocks as well.

That also means that anything the has implemented XFS_IOC_ ioctl
interfaces for prellocation and hole punching (xfs, ocfs2 and gfs2
IIRC) also needs to be protected in the same way.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com>
To: Jan Kara <jack@suse.cz>
Cc: 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 2/8] vfs: Protect write paths by sb_start_write - sb_end_write
Date: Tue, 24 Jan 2012 19:21:19 +1100	[thread overview]
Message-ID: <20120124082119.GO15102@dastard> (raw)
In-Reply-To: <1327091686-23177-3-git-send-email-jack@suse.cz>

On Fri, Jan 20, 2012 at 09:34:40PM +0100, Jan Kara wrote:
> There are three entry points which dirty pages in a filesystem.  mmap (handled
> by block_page_mkwrite()), buffered write (handled by
> __generic_file_aio_write()), and truncate (it can dirty last partial page -
> handled inside each filesystem separately). Protect these places with
> sb_start_write() and sb_end_write().

fallocate can also dirty pages, either during preallocation or hole
punching.  Hence if you are going to promote truncate to
SB_FREEZE_WRITE protection then you need to promote everything else
that can zero partial blocks as well.

That also means that anything the has implemented XFS_IOC_ ioctl
interfaces for prellocation and hole punching (xfs, ocfs2 and gfs2
IIRC) also needs to be protected in the same way.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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  reply	other threads:[~2012-01-24  8:21 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-20 20:34 [PATCH 0/8] Fix filesystem freezing Jan Kara
2012-01-20 20:34 ` Jan Kara
2012-01-20 20:34 ` [PATCH 1/8] fs: Improve filesystem freezing handling Jan Kara
2012-01-20 20:34   ` Jan Kara
2012-02-04  3:03   ` Eric Sandeen
2012-02-04  3:03     ` Eric Sandeen
2012-02-06 15:17     ` Jan Kara
2012-02-06 15:17       ` Jan Kara
2012-01-20 20:34 ` [PATCH 2/8] vfs: Protect write paths by sb_start_write - sb_end_write Jan Kara
2012-01-20 20:34   ` Jan Kara
2012-01-24  8:21   ` Dave Chinner [this message]
2012-01-24  8:21     ` Dave Chinner
2012-01-24 11:44     ` Jan Kara
2012-01-24 11:44       ` Jan Kara
2012-02-05  6:13   ` Eric Sandeen
2012-02-05  6:13     ` Eric Sandeen
2012-02-06 15:33     ` Jan Kara
2012-02-06 15:33       ` Jan Kara
2012-01-20 20:34 ` [PATCH 3/8] ext4: Protect ext4_page_mkwrite & ext4_setattr with " Jan Kara
2012-01-20 20:34   ` Jan Kara
2012-01-20 20:34 ` [PATCH 4/8] xfs: Move ilock before transaction start in xfs_setattr_size() Jan Kara
2012-01-20 20:34   ` Jan Kara
2012-01-24  6:59   ` Dave Chinner
2012-01-24  6:59     ` Dave Chinner
2012-01-24 11:52     ` Jan Kara
2012-01-24 11:52       ` Jan Kara
2012-01-20 20:34 ` [PATCH 5/8] xfs: Protect xfs_file_aio_write() & xfs_setattr_size() with sb_start_write - sb_end_write Jan Kara
2012-01-20 20:34   ` Jan Kara
2012-01-24  7:19   ` Dave Chinner
2012-01-24  7:19     ` Dave Chinner
2012-01-24 19:35     ` Jan Kara
2012-01-24 19:35       ` Jan Kara
2012-02-04  4:30   ` Eric Sandeen
2012-02-04  4:30     ` Eric Sandeen
2012-02-04  4:50     ` Eric Sandeen
2012-02-04  4:50       ` Eric Sandeen
2012-02-05 23:11     ` Dave Chinner
2012-02-05 23:11       ` Dave Chinner
2012-01-20 20:34 ` [PATCH 6/8] xfs: Use generic writers counter instead of m_active_trans counter Jan Kara
2012-01-20 20:34   ` Jan Kara
2012-01-24  8:05   ` Dave Chinner
2012-01-24  8:05     ` Dave Chinner
2012-02-04  2:13     ` Eric Sandeen
2012-02-04  2:13       ` Eric Sandeen
2012-02-04  2:42   ` Eric Sandeen
2012-02-04  2:42     ` Eric Sandeen
2012-02-04  4:34   ` Eric Sandeen
2012-02-04  4:34     ` Eric Sandeen
2012-01-20 20:34 ` [PATCH 7/8] Documentation: Correct s_umount state for freeze_fs/unfreeze_fs Jan Kara
2012-01-20 20:34   ` Jan Kara
2012-01-20 20:34 ` [PATCH 8/8] vfs: Document s_frozen state through freeze_super Jan Kara
2012-01-20 20:34   ` Jan Kara

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