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From: Gang He <ghe@suse.com>
To: Joseph Qi <joseph.qi@linux.alibaba.com>,
	mark@fasheh.com, jlbec@evilplan.org
Cc: linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com,
	akpm@linux-foundation.org
Subject: Re: [PATCH] ocfs2: avoid getting dlm lock of the target directory multiple times during reflink process
Date: Tue, 7 Sep 2021 17:40:26 +0800	[thread overview]
Message-ID: <7510251b-0bf5-f14d-6c44-30385152a883@suse.com> (raw)
In-Reply-To: <41bc413d-0926-0eae-6772-076314bbae53@linux.alibaba.com>

Hi Joseph,

On 2021/9/6 19:14, Joseph Qi wrote:
> Hi Gang,
> 
> 
> On 8/26/21 3:59 PM, Gang He wrote:
>> During the reflink process, we should acquire the target directory
>> inode dlm lock at the beginning, and hold this dlm lock until end
>> of the function.
>> With this patch, we avoid dlm lock ping-pong effect when clone
>> files to the same directory simultaneously from multiple nodes.
>> There is a typical user scenario, users regularly back up files
>> to a specified directory through the reflink feature from the
>> multiple nodes.
>>
> Since now it take dir inode lock across the whole reflink, it may impact
> other concurrent operations under the same directory.
> Have you evaluated such cases?
So far, I do not find there is any risk for taking dir inode lock across 
the reflink function, it will block getting that dir inode lock a little 
time, but avoid ping-pong effect during the reflink function.


Thanks
Gang


> 
> Thanks,
> Joseph
> 
> 


WARNING: multiple messages have this Message-ID
From: Gang He <ghe@suse.com>
To: Joseph Qi <joseph.qi@linux.alibaba.com>,
	mark@fasheh.com, jlbec@evilplan.org
Cc: linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com
Subject: Re: [Ocfs2-devel] [PATCH] ocfs2: avoid getting dlm lock of the target directory multiple times during reflink process
Date: Tue, 7 Sep 2021 17:40:26 +0800	[thread overview]
Message-ID: <7510251b-0bf5-f14d-6c44-30385152a883@suse.com> (raw)
In-Reply-To: <41bc413d-0926-0eae-6772-076314bbae53@linux.alibaba.com>

Hi Joseph,

On 2021/9/6 19:14, Joseph Qi wrote:
> Hi Gang,
> 
> 
> On 8/26/21 3:59 PM, Gang He wrote:
>> During the reflink process, we should acquire the target directory
>> inode dlm lock at the beginning, and hold this dlm lock until end
>> of the function.
>> With this patch, we avoid dlm lock ping-pong effect when clone
>> files to the same directory simultaneously from multiple nodes.
>> There is a typical user scenario, users regularly back up files
>> to a specified directory through the reflink feature from the
>> multiple nodes.
>>
> Since now it take dir inode lock across the whole reflink, it may impact
> other concurrent operations under the same directory.
> Have you evaluated such cases?
So far, I do not find there is any risk for taking dir inode lock across 
the reflink function, it will block getting that dir inode lock a little 
time, but avoid ping-pong effect during the reflink function.


Thanks
Gang


> 
> Thanks,
> Joseph
> 
> 


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  reply	other threads:[~2021-09-07  9:40 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-26  7:59 [PATCH] ocfs2: avoid getting dlm lock of the target directory multiple times during reflink process Gang He
2021-08-26  7:59 ` [Ocfs2-devel] " Gang He
2021-08-31  6:25 ` Gang He
2021-08-31  6:25   ` [Ocfs2-devel] " Gang He
2021-08-31  7:39   ` Joseph Qi
2021-08-31  7:39     ` [Ocfs2-devel] " Joseph Qi
2021-09-07 15:57   ` Wengang Wang
2021-09-07 15:57     ` Wengang Wang
2021-09-08  6:06     ` Gang He
2021-09-08  6:06       ` Gang He
2021-09-08 16:00       ` Wengang Wang
2021-09-08 16:00         ` Wengang Wang
2021-09-14  7:34         ` Gang He
2021-09-14  7:34           ` Gang He
2021-09-14 17:50           ` Wengang Wang
2021-09-17  7:37             ` Gang He
2021-09-17  7:37               ` Gang He
2021-09-06 11:14 ` Joseph Qi
2021-09-06 11:14   ` [Ocfs2-devel] " Joseph Qi
2021-09-07  9:40   ` Gang He [this message]
2021-09-07  9:40     ` Gang He

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