Re: [PATCH v7 10/17] locks: make /proc/locks show IS_FILE_PVT locks with a P suffix

["J. Bruce Fields" <bfields@fieldses.org>]

On Wed, Mar 19, 2014 at 04:45:54PM -0400, Jeff Layton wrote:
> In a later patch, we'll be adding a new type of lock that's owned by
> the struct file instead of the files_struct. Those sorts of locks
> will be flagged with a new IS_FILE_PVT flag.
> 
> Add a "P" suffix to the POSIX lock output in /proc/locks for locks that
> have FL_FILE_PVT set to distinguish them from "classic" POSIX locks.

ACK, though I'm curious:

> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> ---
>  fs/locks.c         | 9 +++++++--
>  include/linux/fs.h | 1 +
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/locks.c b/fs/locks.c
> index 4d4e790150e0..f1b9b149dd39 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -135,6 +135,7 @@
>  #define IS_POSIX(fl)	(fl->fl_flags & FL_POSIX)
>  #define IS_FLOCK(fl)	(fl->fl_flags & FL_FLOCK)
>  #define IS_LEASE(fl)	(fl->fl_flags & (FL_LEASE|FL_DELEG))
> +#define IS_FILE_PVT(fl)	(fl->fl_flags & FL_FILE_PVT)
>  
>  static bool lease_breaking(struct file_lock *fl)
>  {
> @@ -2313,8 +2314,12 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
>  
>  	seq_printf(f, "%lld:%s ", id, pfx);
>  	if (IS_POSIX(fl)) {
> -		seq_printf(f, "%6s %s ",
> -			     (fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ",
> +		if (fl->fl_flags & FL_ACCESS)
> +			seq_printf(f, "ACCESS");

Are FL_ACCESS locks ever put on any global list?  Wouldn't it be a bug
to run across one here?

--b.

> +		else
> +			seq_printf(f, "POSIX%c", IS_FILE_PVT(fl) ? 'P' : ' ');
> +
> +		seq_printf(f, " %s ",
>  			     (inode == NULL) ? "*NOINODE*" :
>  			     mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
>  	} else if (IS_FLOCK(fl)) {
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 7527d96913d3..5ddeb8de5e77 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -888,6 +888,7 @@ static inline int file_check_writeable(struct file *filp)
>  #define FL_SLEEP	128	/* A blocking lock */
>  #define FL_DOWNGRADE_PENDING	256 /* Lease is being downgraded */
>  #define FL_UNLOCK_PENDING	512 /* Lease is being broken */
> +#define FL_FILE_PVT	1024	/* lock is private to the file */
>  
>  /*
>   * Special return value from posix_lock_file() and vfs_lock_file() for
> -- 
> 1.8.5.3
>