[PATCH 16/41] whiteout: jffs2 whiteout support

[Valerie Aurora]

On Mon, Nov 30, 2009 at 02:51:05AM -0500, Erez Zadok wrote:
> In message <1256152779-10054-17-git-send-email-vaurora at redhat.com>, Valerie Aurora writes:
> > From: Felix Fietkau <nbd at openwrt.org>
> > 
> > Add support for whiteout dentries to jffs2.
> > 
> > Signed-off-by: Felix Fietkau <nbd at openwrt.org>
> > Signed-off-by: Valerie Aurora <vaurora at redhat.com>
> > Cc: David Woodhouse <dwmw2 at infradead.org>
> > Cc: linux-mtd at lists.infradead.org
> > ---
> >  fs/jffs2/dir.c        |   77 +++++++++++++++++++++++++++++++++++++++++++++++-
> >  fs/jffs2/fs.c         |    4 ++
> >  fs/jffs2/super.c      |    2 +-
> >  include/linux/jffs2.h |    2 +
> >  4 files changed, 82 insertions(+), 3 deletions(-)
> > 
> > diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
> > index 6f60cc9..46a2e1b 100644
> > --- a/fs/jffs2/dir.c
> > +++ b/fs/jffs2/dir.c
> > @@ -34,6 +34,8 @@ static int jffs2_mknod (struct inode *,struct dentry *,int,dev_t);
> >  static int jffs2_rename (struct inode *, struct dentry *,
> >  			 struct inode *, struct dentry *);
> >  
> > +static int jffs2_whiteout (struct inode *, struct dentry *, struct dentry *);
> > +
> >  const struct file_operations jffs2_dir_operations =
> >  {
> >  	.read =		generic_read_dir,
> > @@ -55,6 +57,7 @@ const struct inode_operations jffs2_dir_inode_operations =
> >  	.rmdir =	jffs2_rmdir,
> >  	.mknod =	jffs2_mknod,
> >  	.rename =	jffs2_rename,
> > +	.whiteout =     jffs2_whiteout,
> >  	.permission =	jffs2_permission,
> >  	.setattr =	jffs2_setattr,
> >  	.setxattr =	jffs2_setxattr,
> > @@ -98,8 +101,18 @@ static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target,
> >  			fd = fd_list;
> >  		}
> >  	}
> > -	if (fd)
> > -		ino = fd->ino;
> > +	if (fd) {
> > +		spin_lock(&target->d_lock);
> > +		switch(fd->type) {
> > +		case DT_WHT:
> > +			target->d_flags |= DCACHE_WHITEOUT;
> > +			break;
> > +		default:
> > +			ino = fd->ino;
> > +			break;
> > +		}
> > +		spin_unlock(&target->d_lock);
> > +	}
> 
> The switch statement above should be simplified into this:
> 
>  if (fd->type == DT_WHT)
> 	target->d_flags |= DCACHE_WHITEOUT;
>  else
> 	ino = fd->ino;

This is because later we add a third case for fallthrus, at which
point a switch statement is easier to read.  But it is confusing and
distracting by itself in this patch, so I changed it as you suggested.


> > +	/* If it's a directory, then check whether it is really empty
> > +	 */
> 
> Format above comment on one line.

Fixxed, thanks.

-VAL