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From: "Ananiev, Leonid I" <leonid.i.ananiev@intel.com>
To: "Zach Brown" <zach.brown@oracle.com>
Cc: "Ken Chen" <kenchen@google.com>, <suparna@in.ibm.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
<linux-kernel@vger.kernel.org>, "linux-aio" <linux-aio@kvack.org>,
"Chris Mason" <chris.mason@oracle.com>
Subject: RE: [PATCH] aio: fix kernel bug when page is temporally busy
Date: Fri, 16 Feb 2007 15:18:58 +0300 [thread overview]
Message-ID: <B41635854730A14CA71C92B36EC22AAC83ABB0@mssmsx411> (raw)
In-Reply-To: <E29B98FF-8DDE-4AA5-AD65-75112B3E0DD6@oracle.com>
Zach Brown wrote:
> It will not return until kiocbSetKicked() is called,
> and that is only called from kick_iocb().
There is no test or wait of Kicked in considered
for (;;) aio_write() loop.
Zach Brown wrote:
>> The proposed patch does not crate this bug if any.
> Right, and I said that in the mail you're quoting.
...
> You're introducing other bugs with the patch.
Could you list other introduced bugs?
>> It is interesting that I've not seen any EIOCBQUEUED returned
>> to aio_run_iocb() during 5 hours aiostress running.
> What arguments are you running aio-stress with? -EIOCBQUEUED is only
> used for O_DIRECT
I wrote in the vary first mail that the panic is appearing in
random write O_DIRECT aio-stress running. Other aio-stress modes
where tested after patching as well.
> and then only in certain circumstances.
Looking closely into sources we can see that
EIOCBQUEUED never may be returned to aio_run_iocb().
include/linux/aio.h says
* If ki_retry returns -EIOCBRETRY ...
Could you point source line which "returns -EIOCBRETRY"?
Leonid
-----Original Message-----
From: Zach Brown [mailto:zach.brown@oracle.com]
Sent: Friday, February 16, 2007 3:01 AM
To: Ananiev, Leonid I
Cc: Ken Chen; suparna@in.ibm.com; Andrew Morton;
linux-kernel@vger.kernel.org; linux-aio; Chris Mason
Subject: Re: [PATCH] aio: fix kernel bug when page is temporally busy
On Feb 15, 2007, at 3:32 PM, Ananiev, Leonid I wrote:
>>> If EIOCBRETRY then generic_file_aio_write() will be recalled for the
>>> same iocb.
>> Only if kick_iocb() is called. It won't be called if i_i_p2_r() was
>> the only thing to return -EIOCBRETRY.
> It is not need to call kick_iocb()
> for generic_file_aio_write() calling.
> It is recalled without any wakeup waiting:
> for (;;) {
> ret = filp->f_op->aio_write(&kiocb, &iov, 1,
> kiocb.ki_pos);
> if (ret != -EIOCBRETRY)
> break;
> wait_on_retry_sync_kiocb(&kiocb);
> }
> Note: wait_on_retry_sync_kiocb() does not wait.
Yes it does. It will not return until kiocbSetKicked() is called,
and that is only called from kick_iocb().
>>> It overwrites -EIOCBQUEUED
> Do you mean that there is one more kernel bug which
> overwrites -EIOCBQUEUED by any errno or number of bytes and this
> new value is returned to caller as an IO result
> while IO is not finished yet.
>
> The proposed patch does not crate this bug if any.
Right, and I said that in the mail you're quoting.
> It actually fixes a kernel panic bag when iocb.users count becomes
> incorrect. The bag " Kernel BUG at fs/aio.c:509" is there because
> aio_run_iocb() have not a chance to differ real EIO and
> EIO which is actually means EAGAYN or EIOCBRETRY.
Yes, I understand the bug you're trying to fix. You're introducing
other bugs with the patch. It will not be merged.
> It is interesting that I've not seen any EIOCBQUEUED returned
> to aio_run_iocb() during 5 hours aiostress running.
What arguments are you running aio-stress with? -EIOCBQUEUED is only
used for O_DIRECT, and then only in certain circumstances.
- z
next prev parent reply other threads:[~2007-02-16 12:20 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-09 4:29 Ananiev, Leonid I
2007-02-09 4:35 ` Andrew Morton
2007-02-09 5:41 ` Ananiev, Leonid I
2007-02-09 5:52 ` Andrew Morton
2007-02-12 22:52 ` Ananiev, Leonid I
2007-02-12 23:21 ` Ananiev, Leonid I
2007-02-09 7:16 ` Suparna Bhattacharya
2007-02-09 9:52 ` Ananiev, Leonid I
2007-02-09 10:11 ` Jiri Kosina
2007-02-10 18:05 ` Ken Chen
2007-02-10 18:17 ` Ananiev, Leonid I
2007-02-10 18:27 ` Ananiev, Leonid I
2007-02-10 21:57 ` Ananiev, Leonid I
2007-02-15 9:16 ` Ananiev, Leonid I
2007-02-15 18:25 ` Zach Brown
2007-02-15 19:11 ` Ananiev, Leonid I
2007-02-15 19:22 ` Zach Brown
2007-02-15 21:06 ` Ananiev, Leonid I
2007-02-15 23:32 ` Ananiev, Leonid I
2007-02-16 0:01 ` Zach Brown
2007-02-16 12:18 ` Ananiev, Leonid I [this message]
2007-02-09 9:54 ` Jiri Kosina
2007-02-09 10:14 ` Andrew Morton
2007-02-09 10:40 ` Jiri Kosina
2007-02-09 11:05 ` Suparna Bhattacharya
2007-02-09 11:18 ` Ananiev, Leonid I
2007-02-09 17:02 ` Zach Brown
2007-02-10 19:36 Ananiev, Leonid I
2007-02-14 17:51 Ananiev, Leonid I
2007-02-15 3:30 ` Andrew Morton
2007-02-15 5:26 ` Ananiev, Leonid I
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