linux-kernel - Re: Overalyfs regression in 4.0

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Date:	Wed, 13 May 2015 20:19:36 +0200
From:	Jordi Pujol Palomer <jordipujolp@...il.com>
To:	Miklos Szeredi <miklos@...redi.hu>
Cc:	Josh Boyer <jwboyer@...oraproject.org>,
	Miklos Szeredi <mszeredi@...e.cz>,
	Vincent Batts <vbatts@...il.com>,
	David Howells <dhowells@...hat.com>,
	linux-unionfs@...r.kernel.org,
	"Linux-Kernel@...r. Kernel. Org" <linux-kernel@...r.kernel.org>
Subject: Re: Overalyfs regression in 4.0

Hello,

Tested-by: Jordi Pujol Palomer <jordipujolp@...il.com>

Have compiled the version 4.0.3 adding this patch, it works in a
Live OS,

# rmdir /mnt/
# mkdir -p /mnt
# touch /mnt/file
# rmdir /mnt/
rmdir: failed to remove ‘/mnt/’: Directory not empty
# uname -a
Linux pcjordi 4.0.3-1-haswell-lnet-amd64 #1 SMP PREEMPT Wed May 13 19:38:19 CEST 2015 x86_64 GNU/Linux
# 

Thanks,

Jordi Pujol


EL Wed, 13 May 2015 17:11:01 +0200
Miklos Szeredi <miklos@...redi.hu> escrigué:

> ---
> Subject: ovl: don't remove non-empty opaque directory
> From: Miklos Szeredi <mszeredi@...e.cz>
> 
> When removing an opaque directory we can't just call rmdir() to check
> for emptyness, because the directory will need to be replaced with a
> whiteout. The replacement is done with RENAME_EXCHANGE, which doesn't
> check emptyness.
> 
> Solution is just to check emptyness by reading the directory.  In the
> future we could add a new rename flag to check for emptyness even for
> RENAME_EXCHANGE to optimize this case.
> 
> Reported-by: Vincent Batts <vbatts@...il.com>
> Signed-off-by: Miklos Szeredi <mszeredi@...e.cz>
> Fixes: 263b4a0fee43 ("ovl: dont replace opaque dir")
> Cc: <stable@...r.kernel.org> # v4.0+
> ---
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