Re: [PATCH 02/10] fsnotify: introduce pre-content permission event

[Jan Kara <jack@suse.cz>]

On Thu 25-07-24 14:19:39, Josef Bacik wrote:
> From: Amir Goldstein <amir73il@gmail.com>
> 
> The new FS_PRE_ACCESS permission event is similar to FS_ACCESS_PERM,
> but it meant for a different use case of filling file content before
> access to a file range, so it has slightly different semantics.
> 
> Generate FS_PRE_ACCESS/FS_ACCESS_PERM as two seperate events, same as
> we did for FS_OPEN_PERM/FS_OPEN_EXEC_PERM.
> 
> FS_PRE_MODIFY is a new permission event, with similar semantics as
> FS_PRE_ACCESS, which is called before a file is modified.
> 
> FS_ACCESS_PERM is reported also on blockdev and pipes, but the new
> pre-content events are only reported for regular files and dirs.
> 
> The pre-content events are meant to be used by hierarchical storage
> managers that want to fill the content of files on first access.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>

The patch looks good. Just out of curiosity:

> diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
> index 8be029bc50b1..21e72b837ec5 100644
> --- a/include/linux/fsnotify_backend.h
> +++ b/include/linux/fsnotify_backend.h
> @@ -56,6 +56,9 @@
>  #define FS_ACCESS_PERM		0x00020000	/* access event in a permissions hook */
>  #define FS_OPEN_EXEC_PERM	0x00040000	/* open/exec event in a permission hook */
>  
> +#define FS_PRE_ACCESS		0x00100000	/* Pre-content access hook */
> +#define FS_PRE_MODIFY		0x00200000	/* Pre-content modify hook */

Why is a hole left here in the flag space?

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR