From: Tao Ma <tm@tao.ma>
To: Eric Sandeen <sandeen@redhat.com>
Cc: linux-ext4@vger.kernel.org, mjt@tls.msk.ru
Subject: Re: DIO process stuck apparently due to dioread_nolock (3.0)
Date: Tue, 16 Aug 2011 14:15:22 +0800 [thread overview]
Message-ID: <4E4A0AFA.7090403@tao.ma> (raw)
In-Reply-To: <4E49447F.105@redhat.com>
Hi Eric,
On 08/16/2011 12:08 AM, Eric Sandeen wrote:
> On 8/13/11 11:02 AM, Tao Ma wrote:
>> From: Tao Ma <boyu.mt@taobao.com>
>>
>> Hi Michael,
>> could you please check whether this patch work for you?
>
> Thanks, this is the patch I meant to send, I guess ;) I think
> I missed the "|=" case before :(
>
> given that every place we set it requires a test and an increment
> if not set, maybe a helper to do all that is in order?
I have decided to leave it to the next merge window. So I will re-send
this patch as a fix and then create another patch for the helper
generalization.
Thanks
Tao
>
> -Eric
>
>>
>> Subject: [PATCH] ext4: Set unwritten flag and increase i_aiodio_unwritten simultaneously.
>> From 4f1d797973da8b5cf79f58cc1e4d22efb9d46d19 Mon Sep 17 00:00:00 2001
>> From: Tao Ma <boyu.mt@taobao.com>
>> Date: Sat, 13 Aug 2011 23:50:28 +0800
>> Subject: [PATCH] ext4: Set unwritten flag and increase i_aiodio_unwritten simultaneously.
>>
>> EXT4_IO_END_UNWRITTEN flag set and the increase of i_aiodio_unwritten should
>> be done simultaneously since ext4_end_io_nolock always clear the flag and
>> decrease the counter in the same time.
>>
>> We don't increase i_aiodio_unwritten when setting EXT4_IO_END_UNWRITTEN so
>> it will go nagative and causes some process to wait forever.
>>
>> Part of the patch came from Eric in his e-mail.
>> http://marc.info/?l=linux-ext4&m=131316851417460&w=2
>>
>> Reported-by: Michael Tokarev<mjt@tls.msk.ru>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>> Signed-off-by: Tao Ma <boyu.mt@taobao.com>
>> ---
>> fs/ext4/inode.c | 9 ++++++++-
>> fs/ext4/page-io.c | 6 ++++--
>> 2 files changed, 12 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
>> index d47264c..40c0b10 100644
>> --- a/fs/ext4/inode.c
>> +++ b/fs/ext4/inode.c
>> @@ -2668,8 +2668,15 @@ static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate)
>> goto out;
>> }
>>
>> - io_end->flag = EXT4_IO_END_UNWRITTEN;
>> + /*
>> + * It may be over-defensive here to check EXT4_IO_END_UNWRITTEN now,
>> + * but being more careful is always safe for the future change.
>> + */
>> inode = io_end->inode;
>> + if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
>> + io_end->flag |= EXT4_IO_END_UNWRITTEN;
>> + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
>> + }
>>
>> /* Add the io_end to per-inode completed io list*/
>> spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
>> diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
>> index 430c401..78839af 100644
>> --- a/fs/ext4/page-io.c
>> +++ b/fs/ext4/page-io.c
>> @@ -334,8 +334,10 @@ submit_and_retry:
>> if ((io_end->num_io_pages >= MAX_IO_PAGES) &&
>> (io_end->pages[io_end->num_io_pages-1] != io_page))
>> goto submit_and_retry;
>> - if (buffer_uninit(bh))
>> - io->io_end->flag |= EXT4_IO_END_UNWRITTEN;
>> + if (buffer_uninit(bh) && !(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
>> + io_end->flag |= EXT4_IO_END_UNWRITTEN;
>> + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
>> + }
>> io->io_end->size += bh->b_size;
>> io->io_next_block++;
>> ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh));
>
> --
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next prev parent reply other threads:[~2011-08-16 6:15 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-10 10:51 DIO process stuck apparently due to dioread_nolock (3.0) Michael Tokarev
2011-08-11 11:59 ` Jan Kara
2011-08-11 12:21 ` Michael Tokarev
2011-08-11 14:01 ` Jan Kara
2011-08-11 20:05 ` Michael Tokarev
2011-08-12 2:46 ` Jiaying Zhang
2011-08-12 6:23 ` Michael Tokarev
2011-08-12 7:07 ` Michael Tokarev
2011-08-12 13:07 ` Jan Kara
2011-08-12 15:55 ` Michael Tokarev
2011-08-12 17:01 ` Eric Sandeen
2011-08-12 17:34 ` Michael Tokarev
2011-08-13 16:02 ` Tao Ma
2011-08-14 20:57 ` Michael Tokarev
2011-08-14 21:07 ` Michael Tokarev
2011-08-15 2:36 ` Tao Ma
2011-08-15 8:00 ` Michael Tokarev
2011-08-15 8:56 ` Michael Tokarev
2011-08-15 9:03 ` Michael Tokarev
2011-08-15 10:28 ` Tao Ma
2011-08-15 23:53 ` Jiaying Zhang
2011-08-16 4:15 ` Tao Ma
2011-08-16 8:38 ` Michael Tokarev
2011-08-16 13:53 ` Jan Kara
2011-08-16 15:03 ` Tao Ma
2011-08-16 21:32 ` Jiaying Zhang
2011-08-16 22:28 ` Michael Tokarev
2011-08-16 23:07 ` Jiaying Zhang
2011-08-17 17:02 ` Ted Ts'o
2011-08-18 6:49 ` Michael Tokarev
2011-08-18 18:54 ` Jiaying Zhang
2011-08-19 3:20 ` Tao Ma
2011-08-19 3:18 ` Tao Ma
2011-08-19 7:05 ` Michael Tokarev
2011-08-19 17:55 ` Jiaying Zhang
2011-08-16 23:59 ` Dave Chinner
2011-08-17 0:08 ` Jiaying Zhang
2011-08-17 2:22 ` Tao Ma
2011-08-17 9:04 ` Jan Kara
2011-08-15 16:08 ` Eric Sandeen
2011-08-16 4:12 ` Tao Ma
2011-08-16 6:15 ` Tao Ma [this message]
2011-08-12 21:19 ` Jan Kara
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