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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Nigel Cunningham <ncunningham@crca.org.au>
Cc: Josef Bacik <josef@redhat.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	chris.mason@oracle.com, hch@lst.de
Subject: Re: [PATCH] Introduce freeze_super and thaw_super for the fsfreeze ioctl
Date: Tue, 23 Mar 2010 23:47:19 +0000	[thread overview]
Message-ID: <20100323234719.GM30031@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20100323231802.GL30031@ZenIV.linux.org.uk>

On Tue, Mar 23, 2010 at 11:18:03PM +0000, Al Viro wrote:
> [snip the horror]
> 
> 	a) traversing superblock list without any locking whatsoever
> 	b) accessing superblock fields <....>
> 	c) <.........................> without making sure that it's not
> going to disappear
> 	d) calling freeze_bdev() without any warranties that its argument
> is not going to be freed under you
> 	e) layering violations all over the place
> etc.

BTW, superblock can be kept alive by an opened file.  umount -l, for example,
will give that.  So it can get freed whenever the last reference to struct
file can go away (AF_UNIX garbage collection, etc.)

  reply	other threads:[~2010-03-23 23:47 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-23 14:22 [PATCH] Introduce freeze_super and thaw_super for the fsfreeze ioctl Josef Bacik
2010-03-23 14:28 ` Al Viro
2010-03-23 14:34   ` Josef Bacik
2010-03-23 14:48     ` Al Viro
2010-03-23 15:03       ` Josef Bacik
2010-03-23 15:09         ` Al Viro
2010-03-23 15:12           ` Al Viro
2010-03-23 15:15             ` Al Viro
2010-03-23 22:31           ` Nigel Cunningham
2010-03-23 23:18             ` Al Viro
2010-03-23 23:47               ` Al Viro [this message]
2010-03-23 23:52               ` Nigel Cunningham
2010-03-23 23:55                 ` Nigel Cunningham
2010-03-24  0:21                   ` Al Viro
2010-03-24  0:25                     ` Nigel Cunningham
2010-03-24  0:03               ` Nigel Cunningham
2010-03-23 18:19 ` Sunil Mushran
2010-03-23 22:25 ` Nigel Cunningham
2010-03-24  1:17   ` Josef Bacik
2010-03-24  5:16     ` Nigel Cunningham

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