linux-kernel - Re: [PATCH] fs: bound mount propagation fix

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Date:	Tue, 12 Apr 2011 14:28:28 +0400
From:	Roman Borisov <ext-roman.borisov@...ia.com>
To:	viro@...iv.linux.org.uk
CC:	Roman Borisov <ext-roman.borisov@...ia.com>,
	linux-kernel@...r.kernel.org, vda.linux@...glemail.com,
	cebbert@...hat.com, virtuoso@...nd.org
Subject: Re: [PATCH] fs: bound mount propagation fix

On 04/01/2011 06:48 PM, Roman Borisov wrote:
> I think MS_SILENT shouldn't be cleared anywhere. I suppose the bug is in
> MS_SHARED options checking. Please see the patch below.
>
> Fixed MS_SHARED, MS_SLAVE, MS_UNBINDABLE option handling;
> Existing options check doesn't allow to have any options combinations
> because of integer comparison (not bitwise).
>
> Signed-off-by: Roman Borisov<ext-roman.borisov@...ia.com>
> ---
>   fs/namespace.c |    2 +-
>   fs/pnode.c     |    6 +++---
>   2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/namespace.c b/fs/namespace.c
> index 2beb0fb..e0cf263 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -1434,7 +1434,7 @@ static int do_change_type(struct path *path, int flag)
>   		return -EINVAL;
>
>   	down_write(&namespace_sem);
> -	if (type == MS_SHARED) {
> +	if (type&  MS_SHARED) {
>   		err = invent_group_ids(mnt, recurse);
>   		if (err)
>   			goto out_unlock;
> diff --git a/fs/pnode.c b/fs/pnode.c
> index 8d5f392..0c9dc54 100644
> --- a/fs/pnode.c
> +++ b/fs/pnode.c
> @@ -128,15 +128,15 @@ static int do_make_slave(struct vfsmount *mnt)
>
>   void change_mnt_propagation(struct vfsmount *mnt, int type)
>   {
> -	if (type == MS_SHARED) {
> +	if (type&  MS_SHARED) {
>   		set_mnt_shared(mnt);
>   		return;
>   	}
>   	do_make_slave(mnt);
> -	if (type != MS_SLAVE) {
> +	if (!(type&  MS_SLAVE)) {
>   		list_del_init(&mnt->mnt_slave);
>   		mnt->mnt_master = NULL;
> -		if (type == MS_UNBINDABLE)
> +		if (type&  MS_UNBINDABLE)
>   			mnt->mnt_flags |= MNT_UNBINDABLE;
>   		else
>   			mnt->mnt_flags&= ~MNT_UNBINDABLE;

Al could you comment please on which of the two approaches you prefer: 
mine or previously Denis's

--
Roman
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