Re: [PATCH v2] ext4: fix fast commit inode enqueueing during a full journal commit

From: Jan Kara
Date: Tue May 28 2024 - 06:52:21 EST


On Tue 28-05-24 12:36:02, Jan Kara wrote:
> On Mon 27-05-24 16:48:24, Luis Henriques wrote:
> > On Mon 27 May 2024 09:29:40 AM +01, Luis Henriques wrote;
> > >>> + /*
> > >>> + * Used to flag an inode as part of the next fast commit; will be
> > >>> + * reset during fast commit clean-up
> > >>> + */
> > >>> + tid_t i_fc_next;
> > >>> +
> > >>
> > >> Do we really need new tid in the inode? I'd be kind of hoping we could use
> > >> EXT4_I(inode)->i_sync_tid for this - I can see we even already set it in
> > >> ext4_fc_track_template() and used for similar comparisons in fast commit
> > >> code.
> > >
> > > Ah, true. It looks like it could be used indeed. We'll still need a flag
> > > here, but a simple bool should be enough for that.
> >
> > After looking again at the code, I'm not 100% sure that this is actually
> > doable. For example, if I replace the above by
> >
> > bool i_fc_next;
> >
> > and set to to 'true' below:

Forgot to comment on this one: I don't think you even need 'bool i_fc_next'
- simply whenever i_sync_tid is greater than committing transaction's tid,
you move the inode to FC_Q_STAGING list in ext4_fc_cleanup().

Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR