Re: [PATCH v6 2/2] xfs: avoid transaction reservation recursion

[Yafang Shao <laoar.shao@gmail.com>]

On Tue, Aug 25, 2020 at 4:56 AM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Mon, Aug 24, 2020 at 01:09:25PM -0700, Andrew Morton wrote:
> > On Mon, 24 Aug 2020 09:42:34 +0800 Yafang Shao <laoar.shao@gmail.com> wrote:
> >
> > > --- a/include/linux/iomap.h
> > > +++ b/include/linux/iomap.h
> > > @@ -271,4 +271,11 @@ int iomap_swapfile_activate(struct swap_info_struct *sis,
> > >  # define iomap_swapfile_activate(sis, swapfile, pagespan, ops)     (-EIO)
> > >  #endif /* CONFIG_SWAP */
> > >
> > > +/* Use the journal_info to indicate current is in a transaction */
> > > +static inline bool
> > > +fstrans_context_active(void)
> > > +{
> > > +   return current->journal_info != NULL;
> > > +}
> >
> > Why choose iomap.h for this?
>
> Because it gets used in iomap/buffered-io.c
>
> I don't think this is necessarily a useful abstraction, to be honest.
> I'd just open-code 'if (current->journal_info)' or !current->journal_info,
> whichever way round the code is:
>
> fs/btrfs/delalloc-space.c:              if (current->journal_info)
> fs/ceph/xattr.c:                if (current->journal_info) {
> fs/gfs2/bmap.c:         if (current->journal_info) {
> fs/jbd2/transaction.c:  if (WARN_ON(current->journal_info)) {
> fs/reiserfs/super.c:    if (!current->journal_info) {
>
> (to pluck a few examples from existing filesystems)

Make sense to me.
I will update it in the next version.

-- 
Thanks
Yafang