linux-kernel - Re: [RFC PATCH v2 4/5] locks: show private lock types in /proc/locks

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Date:	Wed, 20 Nov 2013 15:04:11 -0500
From:	"J. Bruce Fields" <bfields@...ldses.org>
To:	Jeff Layton <jlayton@...hat.com>
Cc:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	nfs-ganesha-devel@...ts.sourceforge.net,
	samba-technical@...ts.samba.org
Subject: Re: [RFC PATCH v2 4/5] locks: show private lock types in /proc/locks

On Wed, Nov 20, 2013 at 03:00:56PM -0500, bfields wrote:
> On Wed, Nov 20, 2013 at 11:45:05AM -0500, Jeff Layton wrote:
> > Show "private" locks in /proc/locks with a 'P' suffix. This does mean
> > that we need to widen the column by one character.
> > 
> > Also, tighten up the check in locks_remove_filp() to ensure that only
> > IS_FILP_PVT locks are removed there.
> 
> So that part belongs in the previous patch?

I think it's that previous patch that actually "turns on" the new user
interface (so after that patch userspace will get a lock instead of
-EINVAL or whatever).

Might be safest to delay doing that until the end of the series so as
not to expose any partial implementation.

--b.

> 
> --b.
> 
> > 
> > Signed-off-by: Jeff Layton <jlayton@...hat.com>
> > ---
> >  fs/locks.c         | 15 +++++++++++----
> >  include/linux/fs.h |  1 +
> >  2 files changed, 12 insertions(+), 4 deletions(-)
> > 
> > diff --git a/fs/locks.c b/fs/locks.c
> > index 3b278a6..d5fb853 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_FILP_PVT(fl)	(fl->fl_flags & FL_FILP_PRIVATE)
> >  
> >  static bool lease_breaking(struct file_lock *fl)
> >  {
> > @@ -357,14 +358,17 @@ static int posix_assign_type(struct file_lock *fl, long type)
> >  	case F_RDLCKP:
> >  		type = F_RDLCK;
> >  		fl->fl_owner = (fl_owner_t)fl->fl_file;
> > +		fl->fl_flags |= FL_FILP_PRIVATE;
> >  		break;
> >  	case F_WRLCKP:
> >  		type = F_WRLCK;
> >  		fl->fl_owner = (fl_owner_t)fl->fl_file;
> > +		fl->fl_flags |= FL_FILP_PRIVATE;
> >  		break;
> >  	case F_UNLCKP:
> >  		type = F_UNLCK;
> >  		fl->fl_owner = (fl_owner_t)fl->fl_file;
> > +		fl->fl_flags |= FL_FILP_PRIVATE;
> >  		break;
> >  	}
> >  
> > @@ -2245,7 +2249,8 @@ void locks_remove_filp(struct file *filp)
> >  
> >  	while ((fl = *before) != NULL) {
> >  		if (fl->fl_file == filp) {
> > -			if (IS_FLOCK(fl) || IS_POSIX(fl)) {
> > +			if (IS_FLOCK(fl) ||
> > +			    (IS_POSIX(fl) && IS_FILP_PVT(fl))) {
> >  				locks_delete_lock(before);
> >  				continue;
> >  			}
> > @@ -2345,13 +2350,15 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
> >  		seq_printf(f, "UNKNOWN UNKNOWN  ");
> >  	}
> >  	if (fl->fl_type & LOCK_MAND) {
> > -		seq_printf(f, "%s ",
> > +		seq_printf(f, "%s  ",
> >  			       (fl->fl_type & LOCK_READ)
> >  			       ? (fl->fl_type & LOCK_WRITE) ? "RW   " : "READ "
> >  			       : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
> > +	} else if (IS_FILP_PVT(fl)) {
> > +		seq_printf(f, "%s ", fl->fl_type == F_WRLCK ?  "WRITEP" : "READP ");
> >  	} else {
> > -		seq_printf(f, "%s ",
> > -			       (lease_breaking(fl))
> > +		seq_printf(f, "%s  ",
> > +			       lease_breaking(fl)
> >  			       ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
> >  			       : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
> >  	}
> > diff --git a/include/linux/fs.h b/include/linux/fs.h
> > index 2d890ce..9890bac 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_FILP_PRIVATE	1024	/* lock is private to the filp */
> >  
> >  /*
> >   * Special return value from posix_lock_file() and vfs_lock_file() for
> > -- 
> > 1.8.3.1
> > 
> > --
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