From: Al Viro <viro@ZenIV.linux.org.uk>
To: Neil Brown <neilb@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>,
linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org,
David Woodhouse <dwmw2@infradead.org>,
linux-mtd@lists.infradead.org
Subject: Re: [RFC] Reinstate NFS exportability for JFFS2.
Date: Fri, 1 Aug 2008 11:03:59 +0100 [thread overview]
Message-ID: <20080801100359.GM28946@ZenIV.linux.org.uk> (raw)
In-Reply-To: <18578.29049.38904.746701@notabene.brown>
On Fri, Aug 01, 2008 at 12:14:17PM +1000, Neil Brown wrote:
> It sounds to me like the core problem here is that the locking regime
> imposed by the VFS simply isn't suitable for JFFS2 .. and a bunch of
> other filesystems.
>
> This seems to suggest that the VFS should be changed.
> Superficially, it seems that changing the locking rules so that the
> callee takes i_mutex rather than the caller taking it would help and,
> in the case of JFFS2, make f->sem redundant. Does that match your
> understanding?
Huh? How could that possibly help? You are not changing the sequence
of operations on locks, you only slightly modify the timing; how could
that possibly eliminate a deadlock? Moreover, how the _hell_ could
making exclusion area smaller make f->sem redundant?
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Neil Brown <neilb@suse.de>
Cc: David Woodhouse <dwmw2@infradead.org>,
Christoph Hellwig <hch@infradead.org>,
linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org,
linux-mtd@lists.infradead.org
Subject: Re: [RFC] Reinstate NFS exportability for JFFS2.
Date: Fri, 1 Aug 2008 11:03:59 +0100 [thread overview]
Message-ID: <20080801100359.GM28946@ZenIV.linux.org.uk> (raw)
In-Reply-To: <18578.29049.38904.746701-wvvUuzkyo1EYVZTmpyfIwg@public.gmane.org>
On Fri, Aug 01, 2008 at 12:14:17PM +1000, Neil Brown wrote:
> It sounds to me like the core problem here is that the locking regime
> imposed by the VFS simply isn't suitable for JFFS2 .. and a bunch of
> other filesystems.
>
> This seems to suggest that the VFS should be changed.
> Superficially, it seems that changing the locking rules so that the
> callee takes i_mutex rather than the caller taking it would help and,
> in the case of JFFS2, make f->sem redundant. Does that match your
> understanding?
Huh? How could that possibly help? You are not changing the sequence
of operations on locks, you only slightly modify the timing; how could
that possibly eliminate a deadlock? Moreover, how the _hell_ could
making exclusion area smaller make f->sem redundant?
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
To: Neil Brown <neilb-l3A5Bk7waGM@public.gmane.org>
Cc: David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [RFC] Reinstate NFS exportability for JFFS2.
Date: Fri, 1 Aug 2008 11:03:59 +0100 [thread overview]
Message-ID: <20080801100359.GM28946@ZenIV.linux.org.uk> (raw)
In-Reply-To: <18578.29049.38904.746701-wvvUuzkyo1EYVZTmpyfIwg@public.gmane.org>
On Fri, Aug 01, 2008 at 12:14:17PM +1000, Neil Brown wrote:
> It sounds to me like the core problem here is that the locking regime
> imposed by the VFS simply isn't suitable for JFFS2 .. and a bunch of
> other filesystems.
>
> This seems to suggest that the VFS should be changed.
> Superficially, it seems that changing the locking rules so that the
> callee takes i_mutex rather than the caller taking it would help and,
> in the case of JFFS2, make f->sem redundant. Does that match your
> understanding?
Huh? How could that possibly help? You are not changing the sequence
of operations on locks, you only slightly modify the timing; how could
that possibly eliminate a deadlock? Moreover, how the _hell_ could
making exclusion area smaller make f->sem redundant?
--
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next prev parent reply other threads:[~2008-08-01 10:04 UTC|newest]
Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-01 19:42 [RFC] Reinstate NFS exportability for JFFS2 David Woodhouse
2008-05-01 20:48 ` Christoph Hellwig
2008-05-01 22:44 ` David Woodhouse
2008-05-02 1:38 ` Neil Brown
2008-05-02 1:38 ` Neil Brown
2008-05-02 11:37 ` David Woodhouse
2008-05-02 11:37 ` David Woodhouse
2008-05-02 14:08 ` J. Bruce Fields
2008-05-02 14:08 ` J. Bruce Fields
2008-05-02 14:08 ` J. Bruce Fields
2008-07-31 21:54 ` David Woodhouse
2008-08-01 0:16 ` Neil Brown
2008-08-01 0:40 ` David Woodhouse
2008-08-01 0:40 ` David Woodhouse
2008-08-01 0:40 ` David Woodhouse
2008-08-01 0:52 ` David Woodhouse
2008-08-01 0:52 ` David Woodhouse
2008-08-01 0:52 ` David Woodhouse
2008-08-01 0:53 ` Chuck Lever
2008-08-01 0:53 ` Chuck Lever
2008-08-01 1:00 ` David Woodhouse
2008-08-01 1:00 ` David Woodhouse
2008-08-01 1:00 ` David Woodhouse
2008-08-01 1:31 ` Chuck Lever
2008-08-01 1:31 ` Chuck Lever
2008-08-01 1:31 ` Chuck Lever
2008-08-01 8:13 ` David Woodhouse
2008-08-01 8:13 ` David Woodhouse
2008-08-01 13:35 ` David Woodhouse
2008-08-01 13:35 ` David Woodhouse
2008-08-01 13:56 ` David Woodhouse
2008-08-01 13:56 ` David Woodhouse
2008-08-01 13:56 ` David Woodhouse
2008-08-01 16:05 ` Chuck Lever
2008-08-01 16:05 ` Chuck Lever
2008-08-01 16:19 ` David Woodhouse
2008-08-01 16:19 ` David Woodhouse
2008-08-01 17:47 ` Chuck Lever
2008-08-01 17:47 ` Chuck Lever
2008-08-02 18:26 ` J. Bruce Fields
2008-08-02 18:26 ` J. Bruce Fields
2008-08-02 20:42 ` David Woodhouse
2008-08-02 20:42 ` David Woodhouse
2008-08-02 20:42 ` David Woodhouse
2008-08-02 21:33 ` J. Bruce Fields
2008-08-02 21:33 ` J. Bruce Fields
2008-08-03 8:39 ` David Woodhouse
2008-08-03 8:39 ` David Woodhouse
2008-08-03 8:39 ` David Woodhouse
2008-08-03 11:56 ` Neil Brown
2008-08-03 11:56 ` Neil Brown
2008-08-03 11:56 ` Neil Brown
2008-08-03 17:15 ` Chuck Lever
2008-08-03 17:15 ` Chuck Lever
2008-08-04 1:03 ` Neil Brown
2008-08-04 1:03 ` Neil Brown
2008-08-04 6:19 ` Chuck Lever
2008-08-04 6:19 ` Chuck Lever
2008-08-04 6:19 ` Chuck Lever
2008-08-05 8:51 ` Dave Chinner
2008-08-05 8:51 ` Dave Chinner
2008-08-05 8:59 ` David Woodhouse
2008-08-05 8:59 ` David Woodhouse
2008-08-05 9:47 ` Dave Chinner
2008-08-05 9:47 ` Dave Chinner
2008-08-05 23:06 ` Neil Brown
2008-08-05 23:06 ` Neil Brown
2008-08-05 23:06 ` Neil Brown
2008-08-06 0:08 ` Dave Chinner
2008-08-06 0:08 ` Dave Chinner
2008-08-06 0:08 ` Dave Chinner
2008-08-06 19:56 ` J. Bruce Fields
2008-08-06 19:56 ` J. Bruce Fields
2008-08-06 20:10 ` David Woodhouse
2008-08-06 20:10 ` David Woodhouse
2008-08-09 16:47 ` David Woodhouse
2008-08-09 16:47 ` David Woodhouse
2008-08-09 16:47 ` David Woodhouse
2008-08-09 19:55 ` David Woodhouse
2008-08-09 19:55 ` David Woodhouse
2008-08-09 20:01 ` [PATCH 1/4] Factor out nfsd_do_readdir() into its own function David Woodhouse
2008-08-09 20:01 ` David Woodhouse
2008-08-09 20:01 ` David Woodhouse
2008-08-09 20:07 ` Christoph Hellwig
2008-08-09 20:07 ` Christoph Hellwig
2008-08-09 20:07 ` Christoph Hellwig
2008-08-09 20:02 ` [PATCH 2/4] Copy XFS readdir hack into nfsd code David Woodhouse
2008-08-09 20:02 ` David Woodhouse
2008-08-09 20:02 ` David Woodhouse
2008-08-09 20:08 ` Christoph Hellwig
2008-08-09 20:08 ` Christoph Hellwig
2008-08-09 20:03 ` [PATCH 3/4] Remove XFS buffered readdir hack David Woodhouse
2008-08-09 20:03 ` David Woodhouse
2008-08-09 20:03 ` David Woodhouse
2008-08-09 20:09 ` Christoph Hellwig
2008-08-09 20:09 ` Christoph Hellwig
2008-08-09 20:09 ` Christoph Hellwig
2008-08-09 20:03 ` [PATCH 4/4] Reinstate NFS exportability David Woodhouse
2008-08-09 20:03 ` David Woodhouse
2008-08-09 20:03 ` David Woodhouse
2008-08-09 20:10 ` Christoph Hellwig
2008-08-09 20:10 ` Christoph Hellwig
2008-08-09 20:10 ` Christoph Hellwig
2008-08-06 19:56 ` [RFC] Reinstate NFS exportability for JFFS2 J. Bruce Fields
2008-08-04 18:41 ` J. Bruce Fields
2008-08-04 18:41 ` J. Bruce Fields
2008-08-04 22:37 ` Neil Brown
2008-08-04 22:37 ` Neil Brown
2008-08-17 18:22 ` Andreas Dilger
2008-08-17 18:22 ` Andreas Dilger
2008-08-17 18:22 ` Andreas Dilger
2008-08-01 2:14 ` Neil Brown
2008-08-01 2:14 ` Neil Brown
2008-08-01 8:50 ` David Woodhouse
2008-08-01 8:50 ` David Woodhouse
2008-08-01 8:50 ` David Woodhouse
2008-08-01 10:03 ` Al Viro [this message]
2008-08-01 10:03 ` Al Viro
2008-08-01 10:03 ` Al Viro
2008-08-01 23:11 ` Neil Brown
2008-08-01 23:11 ` Neil Brown
2008-08-01 23:11 ` Neil Brown
2008-07-31 21:54 ` [PATCH 1/4] Factor out nfsd_do_readdir() into its own function David Woodhouse
2008-07-31 21:54 ` [PATCH 2/4] Copy XFS readdir hack into nfsd code, introduce FS_NO_LOOKUP_IN_READDIR flag David Woodhouse
2008-07-31 21:55 ` [PATCH 3/4] Switch XFS to using FS_NO_LOOKUP_IN_READDIR, remove local readdir hack David Woodhouse
2008-07-31 21:55 ` [PATCH 4/4] [JFFS2] Reinstate NFS exportability David Woodhouse
2008-07-31 21:55 ` David Woodhouse
2008-07-31 21:55 ` David Woodhouse
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