From: Andrew Morton <akpm@osdl.org>
To: Dmitriy Monakhov <dmonakhov@openvz.org>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
Linux Memory Management <linux-mm@kvack.org>, <devel@openvz.org>,
ext2-devel@lists.sourceforge.net,
Andrey Savochkin <saw@swsoft.com>
Subject: Re: [RFC][PATCH] EXT3: problem with page fault inside a transaction
Date: Wed, 11 Oct 2006 23:43:30 -0700 [thread overview]
Message-ID: <20061011234330.efae4265.akpm@osdl.org> (raw)
In-Reply-To: <87mz82vzy1.fsf@sw.ru>
On Thu, 12 Oct 2006 09:57:26 +0400
Dmitriy Monakhov <dmonakhov@openvz.org> wrote:
> While reading Andrew's generic_file_buffered_write patches i've remembered
> one more EXT3 issue.journal_start() in prepare_write() causes different ranking
> violations if copy_from_user() triggers a page fault. It could cause
> GFP_FS allocation, re-entering into ext3 code possibly with a different
> superblock and journal, ranking violation of journalling serialization
> and mmap_sem and page lock and all other kinds of funny consequences.
With the stuff Nick and I are looking at, we won't take pagefaults inside
prepare_write()/commit_write() any more.
> Our customers complain about this issue.
Really? How often?
What on earth are they doing to trigger this? writev() without the 2.6.18
writev() bugfix?
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@osdl.org>
To: Dmitriy Monakhov <dmonakhov@openvz.org>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
Linux Memory Management <linux-mm@kvack.org>,
devel@openvz.org, ext2-devel@lists.sourceforge.net,
Andrey Savochkin <saw@swsoft.com>
Subject: Re: [RFC][PATCH] EXT3: problem with page fault inside a transaction
Date: Wed, 11 Oct 2006 23:43:30 -0700 [thread overview]
Message-ID: <20061011234330.efae4265.akpm@osdl.org> (raw)
In-Reply-To: <87mz82vzy1.fsf@sw.ru>
On Thu, 12 Oct 2006 09:57:26 +0400
Dmitriy Monakhov <dmonakhov@openvz.org> wrote:
> While reading Andrew's generic_file_buffered_write patches i've remembered
> one more EXT3 issue.journal_start() in prepare_write() causes different ranking
> violations if copy_from_user() triggers a page fault. It could cause
> GFP_FS allocation, re-entering into ext3 code possibly with a different
> superblock and journal, ranking violation of journalling serialization
> and mmap_sem and page lock and all other kinds of funny consequences.
With the stuff Nick and I are looking at, we won't take pagefaults inside
prepare_write()/commit_write() any more.
> Our customers complain about this issue.
Really? How often?
What on earth are they doing to trigger this? writev() without the 2.6.18
writev() bugfix?
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next prev parent reply other threads:[~2006-10-12 6:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-12 5:57 [RFC][PATCH] EXT3: problem with page fault inside a transaction Dmitriy Monakhov
2006-10-12 5:57 ` Dmitriy Monakhov
2006-10-12 6:43 ` Andrew Morton [this message]
2006-10-12 6:43 ` Andrew Morton
2006-10-12 7:01 ` Nick Piggin
2006-10-12 7:01 ` Nick Piggin
2006-10-12 7:53 ` Dmitriy Monakhov
2006-10-12 7:53 ` Dmitriy Monakhov
2006-10-12 8:31 ` Nick Piggin
2006-10-12 8:31 ` Nick Piggin
2006-10-12 8:37 ` Andrew Morton
2006-10-12 8:37 ` Andrew Morton
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