[PATCH resend] proc: Fix proc_kill_inodes to kill dentries on all proc superblocks

[Pavel Emelyanov]

Eric W. Biederman wrote:
> It appears we overlooked support for removing generic proc files
> when we added support for multiple proc super blocks.  Handle
> that now.
> 
> Signed-off-by: Eric W. Biederman <ebiederm at xmission.com>

AFAIS this is just making the kill for all the super blocks
we have.

Acked-by: Pavel Emelyanov <xemul at openvz.org>

> ---
>  fs/proc/generic.c  |   38 +++++++++++++++++++++-----------------
>  fs/proc/internal.h |    2 ++
>  fs/proc/root.c     |    2 +-
>  3 files changed, 24 insertions(+), 18 deletions(-)
> 
> diff --git a/fs/proc/generic.c b/fs/proc/generic.c
> index 1bdb624..3906770 100644
> --- a/fs/proc/generic.c
> +++ b/fs/proc/generic.c
> @@ -561,28 +561,32 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
>  static void proc_kill_inodes(struct proc_dir_entry *de)
>  {
>  	struct list_head *p;
> -	struct super_block *sb = proc_mnt->mnt_sb;
> +	struct super_block *sb;
>  
>  	/*
>  	 * Actually it's a partial revoke().
>  	 */
> -	file_list_lock();
> -	list_for_each(p, &sb->s_files) {
> -		struct file * filp = list_entry(p, struct file, f_u.fu_list);
> -		struct dentry * dentry = filp->f_path.dentry;
> -		struct inode * inode;
> -		const struct file_operations *fops;
> -
> -		if (dentry->d_op != &proc_dentry_operations)
> -			continue;
> -		inode = dentry->d_inode;
> -		if (PDE(inode) != de)
> -			continue;
> -		fops = filp->f_op;
> -		filp->f_op = NULL;
> -		fops_put(fops);
> +	spin_lock(&sb_lock);
> +	list_for_each_entry(sb, &proc_fs_type.fs_supers, s_instances) {
> +		file_list_lock();
> +		list_for_each(p, &sb->s_files) {
> +			struct file * filp = list_entry(p, struct file, f_u.fu_list);
> +			struct dentry * dentry = filp->f_path.dentry;
> +			struct inode * inode;
> +			const struct file_operations *fops;
> +
> +			if (dentry->d_op != &proc_dentry_operations)
> +				continue;
> +			inode = dentry->d_inode;
> +			if (PDE(inode) != de)
> +				continue;
> +			fops = filp->f_op;
> +			filp->f_op = NULL;
> +			fops_put(fops);
> +		}
> +		file_list_unlock();
>  	}
> -	file_list_unlock();
> +	spin_unlock(&sb_lock);
>  }
>  
>  static struct proc_dir_entry *proc_create(struct proc_dir_entry **parent,
> diff --git a/fs/proc/internal.h b/fs/proc/internal.h
> index 1820eb2..1b2b6c6 100644
> --- a/fs/proc/internal.h
> +++ b/fs/proc/internal.h
> @@ -78,3 +78,5 @@ static inline int proc_fd(struct inode *inode)
>  {
>  	return PROC_I(inode)->fd;
>  }
> +
> +extern struct file_system_type proc_fs_type;
> diff --git a/fs/proc/root.c b/fs/proc/root.c
> index ec9cb3b..1f86bb8 100644
> --- a/fs/proc/root.c
> +++ b/fs/proc/root.c
> @@ -98,7 +98,7 @@ static void proc_kill_sb(struct super_block *sb)
>  	put_pid_ns(ns);
>  }
>  
> -static struct file_system_type proc_fs_type = {
> +struct file_system_type proc_fs_type = {
>  	.name		= "proc",
>  	.get_sb		= proc_get_sb,
>  	.kill_sb	= proc_kill_sb,