Re: [PATCH v11 1/5] fs: add iput_if_not_last() helper

[Zhou, Yun]

Hi Honza,

On 7/2/2026 10:29 PM, Jan Kara wrote:
> Hi!
>
> On Thu 02-07-26 21:35:47, Zhou, Yun wrote:
> > On 6/30/2026 7:34 PM, Jan Kara wrote:
> > > On Tue 30-06-26 11:05:50, Mateusz Guzik wrote:
> > > > On Mon, Jun 29, 2026 at 07:08:44PM +0800, Yun Zhou wrote:
> > > > > Unlike iput_not_last() which BUG_ON's if called with the last ref,
> > > > > this variant is designed to be called speculatively.
> > > > >
> > > > > Signed-off-by: Yun Zhou <yun.zhou@xxxxxxxxxxxxx>
> > > > > Suggested-by: Jan Kara <jack@xxxxxxx>
> > > > > Reviewed-by: Jan Kara <jack@xxxxxxx>
> > > > > ---
> > > > >    include/linux/fs.h | 13 +++++++++++++
> > > > >    1 file changed, 13 insertions(+)
> > > > >
> > > > > diff --git a/include/linux/fs.h b/include/linux/fs.h
> > > > > index d10897b3a1e3..04f0de78fa7a 100644
> > > > > --- a/include/linux/fs.h
> > > > > +++ b/include/linux/fs.h
> > > > > @@ -2413,6 +2413,19 @@ static inline void super_set_sysfs_name_generic(struct super_block *sb, const ch
> > > > >    extern void ihold(struct inode * inode);
> > > > >    extern void iput(struct inode *);
> > > > >    void iput_not_last(struct inode *);
> > > > > +
> > > > > +/**
> > > > > + * iput_if_not_last - drop an inode reference only if it is not the last one
> > > > > + * @inode: inode to put
> > > > > + *
> > > > > + * Returns true if the reference was dropped, false if this was the last
> > > > > + * reference and the caller must arrange for final iput() in a safe context.
> > > > > + */
> > > > > +static inline bool __must_check iput_if_not_last(struct inode *inode)
> > > > > +{
> > > > > +   return atomic_add_unless(&inode->i_count, -1, 1);
> > > > > +}
> > > > > +
> > > >
> > > > This still could assert on the count, for example:
> > > >         VFS_BUG_ON_INODE(inode_state_read_once(inode) & (I_FREEING | I_CLEAR), inode);
> > > >         VFS_BUG_ON_INODE(atomic_read(&inode->i_count) < 1, inode);
> > >
> > > Yes, it makes sense to be consistent with other helpers. Thanks for the
> > > idea.
> >
> > Should I wait for now, or go ahead and include the two macros mentioned
> > above in v13 as Mateusz suggested? As you know, the v12 series has been
> > fully reviewed [1] , and I'm wondering if making this change now might cause
> > any inconvenience to everyone.
> >
> > [1] https://lore.kernel.org/linux-ext4/20260630100829.1257618-1-yun.zhou@xxxxxxxxxxxxx/T/#t
>
> I think there will be no more feedback to this series. So just include this
> suggested change (keeping current Reviewed-by tags - the change is minimal)
> and submit one more version. Mention in the cover letter that there's only
> minor adjustment to this one patch, everything is reviewed and ready to be
> merged so that Ted knows.
>
>                                                                  Honza
> --
> Jan Kara <jack@xxxxxxxx>
> SUSE Labs, CR

Okay, I'll get right on it. Thank you very much for your reply and your 
strong support on this patch series.

BR,
Yun