From: Chris Mason <mason@suse.com>
To: Andrey Savochkin <saw@saw.sw.com.sg>
Cc: Andrea Arcangeli <andrea@suse.de>, Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org
Subject: Re: EXT3: problem with copy_from_user inside a transaction
Date: Sat, 04 Sep 2004 03:47:44 -0400 [thread overview]
Message-ID: <1094284064.6301.25.camel@watt.suse.com> (raw)
In-Reply-To: <20040903175728.C1834@castle.nmd.msu.ru>
On Fri, 2004-09-03 at 09:57, Andrey Savochkin wrote:
> > This would mean that all the work is done during the commit_write
> > stage. The trick is that we would have to handle -ENOSPC since we might
> > not know we've run out of room until after the data has been copied from
> > userland.
>
> What is the problem -ENOSPC?
> Do you think about the problem of the page existing before this write, it's
> content overwritten, but the filesystem being unable to commit that write
> because it needs more space?
Exactly. In this case, we've effectively corrupted the page cache.
We've copied data in that isn't (and never will be) reflected on disk.
It isn't a horribly difficult case, we just need to overwrite the data
with zeros, making sure to only overwrite the data corresponding to the
-ENOSPC error.
-chris
next prev parent reply other threads:[~2004-09-04 8:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-03 11:05 EXT3: problem with copy_from_user inside a transaction Andrey Savochkin
2004-09-03 12:35 ` Andrea Arcangeli
2004-09-03 12:06 ` Chris Mason
2004-09-03 13:03 ` Andrea Arcangeli
2004-09-03 13:57 ` Andrey Savochkin
2004-09-04 7:47 ` Chris Mason [this message]
2004-09-04 14:33 ` Andrey Savochkin
2004-09-04 20:12 ` Andrey Savochkin
2004-09-07 11:55 ` [RFC][PATCH] " Andrey Savochkin
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