From: Chris Mason <chris.mason@oracle.com>
To: Jeff Layton <jlayton@redhat.com>
Cc: djwong <djwong@us.ibm.com>, Jan Kara <jack@suse.cz>,
Dave Chinner <david@fromorbit.com>,
Joel Becker <jlbec@evilplan.org>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Jens Axboe <axboe@kernel.dk>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Mingming Cao <mcao@us.ibm.com>,
linux-scsi <linux-scsi@vger.kernel.org>
Subject: Re: [RFC] block integrity: Fix write after checksum calculation problem
Date: Mon, 11 Apr 2011 13:41:16 -0400 [thread overview]
Message-ID: <1302543595-sup-4352@think> (raw)
In-Reply-To: <20110411124229.47bc28f6@corrin.poochiereds.net>
Excerpts from Jeff Layton's message of 2011-04-11 12:42:29 -0400:
> > @@ -5839,6 +5844,15 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
> > if (ret < 0)
> > goto out_unlock;
> > ret = 0;
> > +
> > + /*
> > + * write_begin/end might have created a dirty page and someone
> > + * could wander in and start the IO. Make sure that hasn't
> > + * happened.
> > + */
> > + lock_page(page);
> > + wait_on_page_writeback(page);
> > + unlock_page(page);
>
> nit:
>
> The callers of page_mkwrite always lock the page afterward if you
> return from page_mkwrite with it unlocked. If you plan to take page
> lock anyway, it's probably slightly more efficient not to unlock it and
> instead return VM_FAULT_LOCKED.
>
Actually this isn't a nit. Keeping the page locked closes an important
hole where it can become writeback again. It might fix the last
remaining problem.
-chris
next prev parent reply other threads:[~2011-04-11 17:41 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-22 2:00 [RFC] block integrity: Fix write after checksum calculation problem Darrick J. Wong
2011-02-22 5:45 ` Boaz Harrosh
2011-02-22 11:42 ` Jan Kara
2011-02-22 13:02 ` Chris Mason
2011-02-22 19:13 ` Boaz Harrosh
2011-03-04 20:51 ` Darrick J. Wong
2011-03-04 20:53 ` Christoph Hellwig
2011-02-22 16:13 ` Andreas Dilger
2011-02-22 16:40 ` Martin K. Petersen
2011-02-22 19:45 ` Darrick J. Wong
2011-02-22 22:53 ` Dave Chinner
2011-02-23 16:24 ` Martin K. Petersen
2011-02-23 23:47 ` Dave Chinner
2011-02-24 16:43 ` Jan Kara
2011-02-28 8:49 ` Christoph Hellwig
2011-02-22 16:45 ` Martin K. Petersen
2011-02-23 20:24 ` Joel Becker
2011-02-23 20:35 ` Chris Mason
2011-02-23 21:42 ` Joel Becker
2011-02-24 16:47 ` Jan Kara
2011-02-24 17:37 ` Chris Mason
2011-02-24 18:27 ` Darrick J. Wong
2011-02-28 12:54 ` Chris Mason
2011-03-04 21:07 ` Darrick J. Wong
2011-03-04 22:22 ` Andreas Dilger
2011-03-07 19:11 ` Darrick J. Wong
2011-03-07 21:12 ` Chris Mason
2011-03-08 4:56 ` Dave Chinner
2011-03-10 23:57 ` Darrick J. Wong
2011-03-11 16:34 ` Chris Mason
2011-03-11 18:51 ` Darrick J. Wong
2011-03-19 0:07 ` Darrick J. Wong
2011-03-19 2:28 ` Andreas Dilger
2011-03-22 19:23 ` Darrick J. Wong
2011-03-22 21:54 ` Jan Kara
2011-03-21 14:04 ` Jan Kara
2011-03-21 14:24 ` Chris Mason
2011-03-21 16:43 ` Jan Kara
2011-04-06 23:29 ` Darrick J. Wong
2011-04-07 16:44 ` Darrick J. Wong
2011-04-07 16:57 ` Jan Kara
2011-04-08 20:31 ` Darrick J. Wong
2011-04-11 16:42 ` Jeff Layton
2011-04-11 17:41 ` Chris Mason [this message]
2011-04-11 18:25 ` Christoph Hellwig
2011-04-11 18:38 ` Chris Mason
2011-04-12 0:46 ` Mingming Cao
2011-04-12 0:57 ` Christoph Hellwig
2011-04-14 0:48 ` Mingming Cao
2011-04-22 0:02 ` [RFC v2] block integrity: Stabilize(?) pages during writeback Darrick J. Wong
2011-04-22 12:50 ` Chris Mason
2011-04-22 20:34 ` Jan Kara
2011-04-26 0:37 ` Darrick J. Wong
2011-04-26 11:33 ` Chris Mason
2011-05-03 1:59 ` Darrick J. Wong
2011-05-04 1:26 ` Darrick J. Wong
2011-04-26 11:37 ` Jan Kara
2011-05-04 17:37 ` [PATCH v3 0/3] data integrity: Stabilize pages during writeback for ext4 Darrick J. Wong
2011-05-04 18:46 ` Christoph Hellwig
2011-05-04 19:21 ` Chris Mason
2011-05-04 20:00 ` Darrick J. Wong
2011-05-04 23:57 ` Darrick J. Wong
2011-05-05 15:26 ` Jan Kara
2011-05-04 17:39 ` [PATCH v3 1/3] ext4: Clean up some wait_on_page_writeback calls Darrick J. Wong
2011-05-04 17:41 ` [PATCH v3 2/3] ext4: Wait for writeback to complete while making pages writable Darrick J. Wong
2011-05-04 17:42 ` [PATCH v3 3/3] mm: Wait for writeback when grabbing pages to begin a write Darrick J. Wong
2011-05-04 18:48 ` Christoph Hellwig
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