On Mon, Aug 24, 2020 at 09:56:47PM +0100, Matthew Wilcox 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@xxxxxxxxx> 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) {
/me wonders idly if any of the other filesystems that use
current->journal_info can have an active transaction while calling
->writepages...
.... and if so, whether this patchset has taken the wrong path in
trying to use current->journal_info for XFS to re-implement this
warning.....
.... so we'll have to remove or rework this yet again when other
filesystems are converted to use iomap....
/me suspects the btrfs_write_and_wait_transaction() is a path where
this can actually happen...
-Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
