Re: [PATCH 17/18] fs: icache remove inode_lock

Dave Chinner
2010-10-08T08:09:46Z

On Fri, Oct 08, 2010 at 04:03:19AM -0400, Christoph Hellwig wrote:
> On Fri, Oct 08, 2010 at 04:21:31PM +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > All the functionality that the inode_lock protected has now been
> > wrapped up in new independent locks and/or functionality. Hence the
> > inode_lock does not serve a purpose any longer and hence can now be
> > removed.
>
> Might be worth mentioning this also updates the locking / lock order
> documenation all over the place.

Ok.

>
> > --- a/Documentation/filesystems/Locking
> > +++ b/Documentation/filesystems/Locking
> > @@ -114,7 +114,7 @@ alloc_inode:
> > destroy_inode:
> > dirty_inode: (must not sleep)
> > write_inode:
> > -drop_inode: !!!inode_lock!!!
> > +drop_inode: !!!i_lock, sb_inode_list_lock!!!
>
> sb_inode_list_lock now is sb->s_inodes_lock, this also applies in a few
> other places.
>
>
> > +[mandatory]
> > + inode_lock is gone, replaced by fine grained locks. See fs/inode.c
> > +for details of what locks to replace inode_lock with in order to protect
> > +particular things. Most of the time, a filesystem only needs ->i_lock, which
> > +protects *all* the inode state and its membership on lists that was
> > +previously protected with inode_lock.
>
> Which list membership does i_lock protect?

Oops, I missed updating the documentation file. Will fix that up.

> > --- a/fs/notify/inode_mark.c
> > +++ b/fs/notify/inode_mark.c
> > @@ -22,7 +22,7 @@
> > #include <linux/module.h>
> > #include <linux/mutex.h>
> > #include <linux/spinlock.h>
> > -#include <linux/writeback.h> /* for inode_lock */
> > +#include <linux/writeback.h>
>
> Do we still need writeback.h here?
>
> > @@ -76,7 +76,7 @@
> > #include <linux/buffer_head.h>
> > #include <linux/capability.h>
> > #include <linux/quotaops.h>
> > -#include <linux/writeback.h> /* for inode_lock, oddly enough.. */
> > +#include <linux/writeback.h>
>
> Same here.

I'll check them and clean it up appropriately.

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com