From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To: Namjae Jeon <linkinjeon@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-fsdevel@vger.kernel.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 5/5] fat: add mutex lock to fat_build_inode
Date: Wed, 31 Oct 2012 09:46:49 +0900 [thread overview]
Message-ID: <87390va2o6.fsf@devron.myhome.or.jp> (raw)
In-Reply-To: <CAKYAXd_eA3naT84qnVpPGcc9t4ysc45GqKk5xktXyQWaFp2MOQ@mail.gmail.com> (Namjae Jeon's message of "Tue, 30 Oct 2012 13:24:26 +0900")
Namjae Jeon <linkinjeon@gmail.com> writes:
> 2012/10/30, Andrew Morton <akpm@linux-foundation.org>:
>> On Sun, 28 Oct 2012 10:53:43 +0900
>> Namjae Jeon <linkinjeon@gmail.com> wrote:
>>
>>> From: Namjae Jeon <namjae.jeon@samsung.com>
>>>
>>> fat_nfs_get_inode does not hold i_mutex of parent directory.So add
>>> lock to fat_build_inode.
>>
> Hi. Andrew.
>> Well.. why? Presumably this patch fixes some race. A good
>> description of that race would be useful - partly because others may
>> then be able to suggest alternative ways of fixing that bug.
> We are making use of fat_build_inode to build the inode using 'i_pos'.
> Since, this function is local to FAT and when mounted over NFS. We can
> make use of FAT parallely from local NFS Server and mounted from NFS
> client. So, in order to avoid race to multiple regeneration for the
> same 'i_pos' - we have introduced this locking.
This lock fixes the NFS patches. FAT inode is embedded into
directory. So usual local ->lookup path is exclusive by
inode->i_mutex. But NFS patches (current -mm, IIRC) introduce the new
path for FH => inode lookup.
So, this lock is introduced.
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
prev parent reply other threads:[~2012-10-31 0:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-28 1:53 [PATCH 5/5] fat: add mutex lock to fat_build_inode Namjae Jeon
2012-10-29 23:49 ` Andrew Morton
2012-10-30 4:24 ` Namjae Jeon
2012-10-31 0:46 ` OGAWA Hirofumi [this message]
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