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

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Date:	Fri, 06 Jul 2012 15:33:44 -0500
From:	"Steven J. Magnani" <steve@...idescorp.com>
To:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] fat (exportfs): reconnect file handles to evicted
 inodes/dentries

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.

Steve

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