Re: [PATCH V8 08/11] fs: Define I_DONTCACNE in VFS layer

[Ira Weiny]

On Wed, Apr 15, 2020 at 08:18:32AM -0700, Darrick J. Wong wrote:
> On Wed, Apr 15, 2020 at 10:52:16AM +0200, Jan Kara wrote:
> > There's a typo in the subject - I_DONTCACNE.
> > 
> > On Tue 14-04-20 23:45:20, ira.weiny@xxxxxxxxx wrote:
> > > From: Ira Weiny <ira.weiny@xxxxxxxxx>
> > > 
> > > DAX effective mode changes (setting of S_DAX) require inode eviction.
> > > 
> > > Define a flag which can be set to inform the VFS layer that inodes
> > > should not be cached.  This will expedite the eviction of those nodes
> > > requiring reload.
> > > 
> > > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> > > ---
> > >  include/linux/fs.h | 6 +++++-
> > >  1 file changed, 5 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/include/linux/fs.h b/include/linux/fs.h
> > > index a818ced22961..e2db71d150c3 100644
> > > --- a/include/linux/fs.h
> > > +++ b/include/linux/fs.h
> > > @@ -2151,6 +2151,8 @@ static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
> > >   *
> > >   * I_CREATING		New object's inode in the middle of setting up.
> > >   *
> > > + * I_DONTCACHE		Do not cache the inode
> > > + *
> > 
> > Maybe, I'd be more specific here and write: "Evict inode as soon as it is
> > not used anymore"?
> 
> I had the same two comments about the V7 version of this patch...

Sorry I must have missed it.

Done for V9,
Ira

> 
> --D
> 
> > Otherwise the patch looks good to me so feel free to add:
> > 
> > Reviewed-by: Jan Kara <jack@xxxxxxx>
> > 
> > Also it would be good to CC Al Viro on this one (and the dentry flag) I
> > guess.
> > 
> > 								Honza
> > 
> > >   * Q: What is the difference between I_WILL_FREE and I_FREEING?
> > >   */
> > >  #define I_DIRTY_SYNC		(1 << 0)
> > > @@ -2173,6 +2175,7 @@ static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
> > >  #define I_WB_SWITCH		(1 << 13)
> > >  #define I_OVL_INUSE		(1 << 14)
> > >  #define I_CREATING		(1 << 15)
> > > +#define I_DONTCACHE		(1 << 16)
> > >  
> > >  #define I_DIRTY_INODE (I_DIRTY_SYNC | I_DIRTY_DATASYNC)
> > >  #define I_DIRTY (I_DIRTY_INODE | I_DIRTY_PAGES)
> > > @@ -3042,7 +3045,8 @@ extern int inode_needs_sync(struct inode *inode);
> > >  extern int generic_delete_inode(struct inode *inode);
> > >  static inline int generic_drop_inode(struct inode *inode)
> > >  {
> > > -	return !inode->i_nlink || inode_unhashed(inode);
> > > +	return !inode->i_nlink || inode_unhashed(inode) ||
> > > +		(inode->i_state & I_DONTCACHE);
> > >  }
> > >  
> > >  extern struct inode *ilookup5_nowait(struct super_block *sb,
> > > -- 
> > > 2.25.1
> > > 
> > -- 
> > Jan Kara <jack@xxxxxxxx>
> > SUSE Labs, CR