linux-kernel - Re: [PATCH 2/2] fat (exportfs): reconnect file handles to evicted inodes/dentries

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Message-ID: <871ukobntl.fsf@devron.myhome.or.jp>
Date:	Sat, 07 Jul 2012 06:07:50 +0900
From:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To:	"Steven J. Magnani" <steve@...idescorp.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] fat (exportfs): reconnect file handles to evicted inodes/dentries

"Steven J. Magnani" <steve@...idescorp.com> writes:

> On Wed, 2012-07-04 at 20:07 +0900, OGAWA Hirofumi wrote: 
>> Please don't add new lock_super() usage if it is not necessary. Almost
>> all of lock_super() just replaced lock_kernel() usage. It rather should
>> be removed in future.  Probably, this should use inode->i_mutex instead.
>> 
>> BTW, the above issue is same with all of directory read.
>
> I don't think there's really an alternative here. The cases addressed by
> this patch all involve walking on-disk structures via
> unofficial/temporary inodes created from information in the NFS handle
> (i.e., outside the normal inode creation paths). When this process is
> successful we end up with "official" connected inodes/dentries, but
> getting there is really a "bottom up" strategy instead of the usual "top
> down" approach.
>
> Because the "bottom up" method is lacking guarantees that "top down"
> takes for granted - i.e., that a cluster on disk that's supposed to be a
> directory actually *is* a directory -  I am adding some defensive code
> in the next spin of the patch.

I'm not sure what you meant. Where is the problem? ->get_name()? If so,
it has parent dentry parameter. What is the wrong if we take
mutex_lock(parent->d_inode)?

Thanks.
-- 
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
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