Re: [PATCH] fanotify: store fanotify_init() flags in group's fanotify_data

[Jan Kara <jack@suse.cz>]

On Tue 18-09-18 18:44:34, Amir Goldstein wrote:
> This averts the need to re-generate flags in fanotify_show_fdinfo()
> and sets the scene for addition of more upcoming flags without growing
> new members to the fanotify_data struct.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>

Thanks. I've taken this patch to my tree for the next merge window.

								Honza

> ---
> 
> Jan,
> 
> Please consider this small "cleanup" patch for next.
> It's part of my fanotify_dentry series, so wasn't going to send it out
> yet, but seems like other developers can find it useful [1] in the mean
> while.
> 
> Thanks,
> Amir.
> 
> [1] https://lkml.org/lkml/2018/9/18/942
> 
>  fs/notify/fanotify/fanotify_user.c |  9 +++++----
>  fs/notify/fdinfo.c                 | 24 +-----------------------
>  include/linux/fsnotify_backend.h   |  4 ++--
>  3 files changed, 8 insertions(+), 29 deletions(-)
> 
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 1347c588f778..0562738a4c51 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -191,7 +191,8 @@ static int process_access_response(struct fsnotify_group *group,
>  	if (fd < 0)
>  		return -EINVAL;
>  
> -	if ((response & FAN_AUDIT) && !group->fanotify_data.audit)
> +	if ((response & FAN_AUDIT) &&
> +	    !(group->fanotify_data.flags & FAN_ENABLE_AUDIT))
>  		return -EINVAL;
>  
>  	event = dequeue_event(group, fd);
> @@ -701,8 +702,8 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
>  	struct user_struct *user;
>  	struct fanotify_event_info *oevent;
>  
> -	pr_debug("%s: flags=%d event_f_flags=%d\n",
> -		__func__, flags, event_f_flags);
> +	pr_debug("%s: flags=%x event_f_flags=%x\n",
> +		 __func__, flags, event_f_flags);
>  
>  	if (!capable(CAP_SYS_ADMIN))
>  		return -EPERM;
> @@ -798,13 +799,13 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
>  		fd = -EPERM;
>  		if (!capable(CAP_AUDIT_WRITE))
>  			goto out_destroy_group;
> -		group->fanotify_data.audit = true;
>  	}
>  
>  	fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
>  	if (fd < 0)
>  		goto out_destroy_group;
>  
> +	group->fanotify_data.flags = flags;
>  	return fd;
>  
>  out_destroy_group:
> diff --git a/fs/notify/fdinfo.c b/fs/notify/fdinfo.c
> index 25385e336ac7..348a184bcdda 100644
> --- a/fs/notify/fdinfo.c
> +++ b/fs/notify/fdinfo.c
> @@ -142,31 +142,9 @@ static void fanotify_fdinfo(struct seq_file *m, struct fsnotify_mark *mark)
>  void fanotify_show_fdinfo(struct seq_file *m, struct file *f)
>  {
>  	struct fsnotify_group *group = f->private_data;
> -	unsigned int flags = 0;
> -
> -	switch (group->priority) {
> -	case FS_PRIO_0:
> -		flags |= FAN_CLASS_NOTIF;
> -		break;
> -	case FS_PRIO_1:
> -		flags |= FAN_CLASS_CONTENT;
> -		break;
> -	case FS_PRIO_2:
> -		flags |= FAN_CLASS_PRE_CONTENT;
> -		break;
> -	}
> -
> -	if (group->max_events == UINT_MAX)
> -		flags |= FAN_UNLIMITED_QUEUE;
> -
> -	if (group->fanotify_data.max_marks == UINT_MAX)
> -		flags |= FAN_UNLIMITED_MARKS;
> -
> -	if (group->fanotify_data.audit)
> -		flags |= FAN_ENABLE_AUDIT;
>  
>  	seq_printf(m, "fanotify flags:%x event-flags:%x\n",
> -		   flags, group->fanotify_data.f_flags);
> +		   group->fanotify_data.flags, group->fanotify_data.f_flags);
>  
>  	show_fdinfo(m, f, fanotify_fdinfo);
>  }
> diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
> index 81b88fc9df31..8e91341cbd8a 100644
> --- a/include/linux/fsnotify_backend.h
> +++ b/include/linux/fsnotify_backend.h
> @@ -189,10 +189,10 @@ struct fsnotify_group {
>  			/* allows a group to block waiting for a userspace response */
>  			struct list_head access_list;
>  			wait_queue_head_t access_waitq;
> -			int f_flags;
> +			int flags;           /* flags from fanotify_init() */
> +			int f_flags; /* event_f_flags from fanotify_init() */
>  			unsigned int max_marks;
>  			struct user_struct *user;
> -			bool audit;
>  		} fanotify_data;
>  #endif /* CONFIG_FANOTIFY */
>  	};
> -- 
> 2.17.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR