From: Namjae Jeon <linkinjeon@gmail.com>
To: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: "Steven J. Magnani" <steve@digidescorp.com>,
Al Viro <viro@zeniv.linux.org.uk>,
akpm@linux-foundation.org, bfields@fieldses.org,
linux-kernel@vger.kernel.org,
Namjae Jeon <namjae.jeon@samsung.com>,
Ravishankar N <ravi.n1@samsung.com>,
Amit Sahrawat <a.sahrawat@samsung.com>
Subject: Re: [PATCH v2 1/5] fat: allocate persistent inode numbers
Date: Wed, 12 Sep 2012 00:13:29 +0900 [thread overview]
Message-ID: <CAKYAXd-gO5Pw=0unjB=YQJhu6W=g7VpZYnmHXkve-k8_4VjpgA@mail.gmail.com> (raw)
In-Reply-To: <87oblc4u6f.fsf@devron.myhome.or.jp>
2012/9/11 OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>:
> Namjae Jeon <linkinjeon@gmail.com> writes:
>
>>> Since rename() will be disabled on stable ino patches, this will be
>>> unfixable, so rather maybe it is worse.
>> Currently with our patchset : only rename issue (could not find any
>> correct approach to ignore this. If we do not update this immediately
>> at i_pos change – it is just delaying the problem). And we can return
>> EBUSY when rename is called while process is opening file with rename
>> limitation. Without our patchset also - the rename issue can occur
>> over NFS file access - when the inode is evicted from the SERVER
>> cache.
>
> Important difference is whether rename issue is unfixable or not.
Currently I don't have any idea to fix rename issue in -mm.
>
>> I think that it is unfixable because we can not know i_pos of inode
>> changed by rename.
>> And even though we know it, there is no rebuild inode routine in -mm.
>> And It even can not fix in our patches.
>
>>> And are you tried https://lkml.org/lkml/2012/6/29/381 patches? It sounds
>>> like to improve performance by enabling lookupcache.
>> We checked this patches when facing estale issue in -mm.
>> But It is no use, these patches just retry system call one more when
>> estale error.
>
> What happens if client retried from lookup() after -ESTALE? (client NFS
> doesn't have the name of entry anymore?)
Need to rebuild inode routine because inode cache is already evicted on Server.
>
> I'm assuming the retry means - it restarts from building the NFS file
> handle. I might be just wrong here though.
As I remember, just retry in VFS of NFS client..I heard this patch is
needed for
a very specific set of circumstances where an entry goes stale once
between the lookup and the actual operation(s).
It is not related with current issues(inode cache eviction on server).
>
>>> I'd like to be knowing the critical reason we have to replace it.
>> I arrange to help your decision as the following.
>>
>> 1. lookup cache is enable at default in NFS. So estale error can be
>> easily occurred in -mm.
>> 2. If lookup cache is disable, there is rename issue and file lookup
>> performance is dropped in -mm.
>> 4. If we use our patches, there is rename issue. but we can use VFAT
>> over NFS with lookup cache enable.
>> 5. If we use read-only with our patches, there is no issue.
>
> Again, I'm care about whether rename issue is unfixable or not.
I think that It is unfixable in -mm.
>In stable ino patches, it will never be fixable.
>
>
> What do you think about this rename issue, Steven?
> --
> OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
next prev parent reply other threads:[~2012-09-11 15:13 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-04 15:57 [PATCH v2 1/5] fat: allocate persistent inode numbers Namjae Jeon
2012-09-04 16:17 ` Al Viro
2012-09-05 14:08 ` Namjae Jeon
2012-09-05 14:56 ` OGAWA Hirofumi
2012-09-06 6:46 ` Namjae Jeon
2012-09-06 12:19 ` OGAWA Hirofumi
2012-09-06 13:39 ` Namjae Jeon
2012-09-07 7:01 ` Namjae Jeon
2012-09-07 12:15 ` Steven J. Magnani
2012-09-09 9:32 ` OGAWA Hirofumi
2012-09-09 11:29 ` OGAWA Hirofumi
2012-09-10 12:03 ` Namjae Jeon
2012-09-10 14:00 ` OGAWA Hirofumi
2012-09-11 12:00 ` Namjae Jeon
2012-09-11 12:31 ` OGAWA Hirofumi
2012-09-11 15:13 ` Namjae Jeon [this message]
2012-09-11 15:47 ` OGAWA Hirofumi
2012-09-12 14:12 ` Namjae Jeon
2012-09-12 14:32 ` J. Bruce Fields
2012-09-12 17:03 ` OGAWA Hirofumi
2012-09-12 17:11 ` J. Bruce Fields
2012-09-12 17:38 ` OGAWA Hirofumi
2012-09-12 17:45 ` J. Bruce Fields
2012-09-12 18:49 ` OGAWA Hirofumi
2012-09-13 8:11 ` Namjae Jeon
2012-09-13 8:33 ` OGAWA Hirofumi
2012-09-13 11:20 ` J. Bruce Fields
2012-09-13 12:17 ` OGAWA Hirofumi
2012-09-13 14:24 ` Namjae Jeon
2012-09-13 14:46 ` J. Bruce Fields
2012-09-13 15:34 ` OGAWA Hirofumi
2012-09-14 8:51 ` Namjae Jeon
2012-09-10 12:28 ` Steven J. Magnani
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