From: Andrew Morton <akpm@linux-foundation.org>
To: Neil Brown <neilb@suse.de>
Cc: linux-fsdevel@vger.kernel.org, nfsv4@linux-nfs.org,
linux-ext4@vger.kernel.org, cmm@us.ibm.com,
linux-kernel@vger.kernel.org
Subject: Re: [EXT4 set 4][PATCH 1/5] i_version:64 bit inode version
Date: Tue, 10 Jul 2007 22:22:09 -0700 [thread overview]
Message-ID: <20070710222209.5078e20b.akpm@linux-foundation.org> (raw)
In-Reply-To: <18068.25879.745638.343290@notabene.brown>
On Wed, 11 Jul 2007 15:05:27 +1000 Neil Brown <neilb@suse.de> wrote:
>
> It just occurred to me:
>
> If i_version is 64bit, then knfsd would need to be careful when
> reading it on a 32bit host. What are the locking rules?
>
> Presumably it is only updated under i_mutex protection, but having to
> get i_mutex to read it would seem a little heavy handed.
>
> Should it use a seqlock like i_size?
> Could we use the same seqlock that i_size uses, or would we need a
> separate one?
>
seqlocks are a bit of a pain to use (we've had plenty of deadlocks on the
i_size one). We could reuse inode.i_lock for this modification. Its
mandate is "general purpose innermost lock to protect stuff in this inode".
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Neil Brown <neilb@suse.de>
Cc: cmm@us.ibm.com, linux-fsdevel@vger.kernel.org,
nfsv4@linux-nfs.org, linux-ext4@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [EXT4 set 4][PATCH 1/5] i_version:64 bit inode version
Date: Tue, 10 Jul 2007 22:22:09 -0700 [thread overview]
Message-ID: <20070710222209.5078e20b.akpm@linux-foundation.org> (raw)
In-Reply-To: <18068.25879.745638.343290@notabene.brown>
On Wed, 11 Jul 2007 15:05:27 +1000 Neil Brown <neilb@suse.de> wrote:
>
> It just occurred to me:
>
> If i_version is 64bit, then knfsd would need to be careful when
> reading it on a 32bit host. What are the locking rules?
>
> Presumably it is only updated under i_mutex protection, but having to
> get i_mutex to read it would seem a little heavy handed.
>
> Should it use a seqlock like i_size?
> Could we use the same seqlock that i_size uses, or would we need a
> separate one?
>
seqlocks are a bit of a pain to use (we've had plenty of deadlocks on the
i_size one). We could reuse inode.i_lock for this modification. Its
mandate is "general purpose innermost lock to protect stuff in this inode".
next prev parent reply other threads:[~2007-07-11 5:22 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-01 7:37 [EXT4 set 4][PATCH 1/5] i_version:64 bit inode version Mingming Cao
2007-07-02 14:58 ` Mingming Cao
2007-07-03 14:24 ` Trond Myklebust
2007-07-03 21:56 ` Andreas Dilger
2007-07-03 22:15 ` J. Bruce Fields
2007-07-03 23:32 ` Andreas Dilger
2007-07-03 23:32 ` Andreas Dilger
2007-07-06 13:51 ` J. Bruce Fields
2007-07-06 22:53 ` Andreas Dilger
2007-07-09 21:16 ` Mingming Cao
2007-07-10 23:30 ` Andrew Morton
2007-07-10 22:09 ` Mingming Cao
2007-07-10 22:09 ` Mingming Cao
2007-07-11 1:22 ` Andrew Morton
2007-07-11 0:19 ` Mingming Cao
2007-07-11 0:19 ` Mingming Cao
2007-07-11 4:22 ` Andrew Morton
2007-07-11 2:27 ` Mingming Cao
2007-07-11 16:57 ` J. Bruce Fields
2007-07-11 3:21 ` Neil Brown
2007-07-11 2:09 ` Mingming Cao
2007-07-11 5:17 ` Andrew Morton
2007-07-11 5:17 ` Andrew Morton
2007-07-11 3:18 ` Mingming Cao
2007-07-11 6:35 ` Andrew Morton
2007-07-11 3:34 ` Trond Myklebust
2007-07-11 3:34 ` Trond Myklebust
2007-07-11 11:41 ` Andreas Dilger
2007-07-11 11:41 ` Andreas Dilger
2007-07-11 5:05 ` Neil Brown
2007-07-11 5:22 ` Andrew Morton [this message]
2007-07-11 5:22 ` Andrew Morton
2007-07-11 14:28 ` Dave Kleikamp
2007-07-11 20:04 ` J. Bruce Fields
2007-07-11 20:04 ` J. Bruce Fields
2007-07-12 4:56 ` Andreas Dilger
2007-07-11 17:26 ` J. Bruce Fields
2007-07-11 17:26 ` J. Bruce Fields
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