Re: [PATCH] Add FS_CLOSE_READ and FS_CLOSE_NOREAD flag to fsnotify

[Jan Kara <jack@suse.cz>]

On Sun 20-09-15 23:07:35, Patrick Puzik wrote:
> Attached is a patch which is a preparation for the later support of an
> event notification, when an unreadable or readable file was closed.

So I'm missing two things in this patch (or rather changelog):

1) When should these events be generated? I can kind of infer this from the
comment and event name but for example FS_CLOSE_WRITE and FS_CLOSE_NOWRITE
are exclusive. I suppose we will generate FS_CLOSE_READ or FS_CLOSE_NOREAD
in addition to that?

2) What is the use case? I.e. what is your application doing that current
notification events are not enough?

								Honza
> 
> Signed-off-by: Patrick Puzik <p.puzik91@gmail.com>
> ---
>  include/linux/fsnotify_backend.h | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
> index 533c440..7563679 100644
> --- a/include/linux/fsnotify_backend.h
> +++ b/include/linux/fsnotify_backend.h
> @@ -28,6 +28,8 @@
>  #define FS_ATTRIB		0x00000004	/* Metadata changed */
>  #define FS_CLOSE_WRITE		0x00000008	/* Writtable file was closed */
>  #define FS_CLOSE_NOWRITE	0x00000010	/* Unwrittable file closed */
> +#define FS_CLOSE_READ           0x00000011      /* Unreadable file closed */
> +#define FS_CLOSE_NOREAD         0x00000012      /* Readable file was closed */
>  #define FS_OPEN			0x00000020	/* File was opened */
>  #define FS_MOVED_FROM		0x00000040	/* File was moved from X */
>  #define FS_MOVED_TO		0x00000080	/* File was moved to Y */
> @@ -56,9 +58,10 @@
>  
>  /* This is a list of all events that may get sent to a parernt based on fs event
>   * happening to inodes inside that directory */
> -#define FS_EVENTS_POSS_ON_CHILD   (FS_ACCESS | FS_MODIFY | FS_ATTRIB |\
> -				   FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN |\
> -				   FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\
> +#define FS_EVENTS_POSS_ON_CHILD   (FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
> +				   FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | \
> +				   FS_CLOSE_READ | FS_CLOSE_NOREAD | FS_OPEN | \
> +				   FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \
>  				   FS_DELETE | FS_OPEN_PERM | FS_ACCESS_PERM)
>  
>  #define FS_MOVE			(FS_MOVED_FROM | FS_MOVED_TO)
> @@ -66,7 +69,8 @@
>  #define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM)
>  
>  #define ALL_FSNOTIFY_EVENTS (FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
> -			     FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN | \
> +			     FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | \
> +			     FS_CLOSE_READ | FS_CLOSE_NOREAD | FS_OPEN | \
>  			     FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \
>  			     FS_DELETE | FS_DELETE_SELF | FS_MOVE_SELF | \
>  			     FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
> -- 
> 2.4.3
> 
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR