On Mon, Jul 30, 2018 at 01:09:09PM -0700, Darrick J. Wong wrote:
> On Mon, Jul 30, 2018 at 12:45:07PM -0400, Brian Foster wrote:
> > Log intent recovery is the last user of an external (on-stack)
> > dfops. The pattern exists because the dfops is used to collect
> > additional deferred operations queued during the whole recovery
> > sequence. The dfops is finished with a new transaction after intent
> > recovery completes.
> >
> > We already have a mechanism to create an empty, container-like
> > transaction to support the scrub infrastructure. We can reuse that
> > mechanism here to drop the final user of external dfops. This
> > facilitates folding dfops state (i.e., dop_low) into the
> > transaction, the elimination of now unused external dfops support
> > and also eliminates the only caller of __xfs_defer_cancel().
> >
> > Replace the on-stack dfops with an empty transaction and pass it
> > around to the various helpers that queue and finish deferred
> > operations during intent recovery.
> >
> > Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
> > ---
> > fs/xfs/xfs_bmap_item.c | 12 +++++------
> > fs/xfs/xfs_bmap_item.h | 3 +--
> > fs/xfs/xfs_log_recover.c | 42 ++++++++++++++++++--------------------
> > fs/xfs/xfs_refcount_item.c | 12 +++++------
> > fs/xfs/xfs_refcount_item.h | 3 +--
> > 5 files changed, 34 insertions(+), 38 deletions(-)
> >
> > diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
> > index e1d6c127b07d..992235e7c761 100644
> > --- a/fs/xfs/xfs_bmap_item.c
> > +++ b/fs/xfs/xfs_bmap_item.c
> > @@ -375,9 +375,8 @@ xfs_bud_init(
> > */
> > int
> > xfs_bui_recover(
> > - struct xfs_mount *mp,
> > - struct xfs_bui_log_item *buip,
> > - struct xfs_defer_ops *dfops)
> > + struct xfs_trans *itp,
>
> "itp"?
>
> Oh, the intent-holder transaction...
>
Yeah..
> > + struct xfs_bui_log_item *buip)
> > {
> > int error = 0;
> > unsigned int bui_type;
...
> > diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
> > index 7776fde9430c..6650b790e43b 100644
> > --- a/fs/xfs/xfs_log_recover.c
> > +++ b/fs/xfs/xfs_log_recover.c
...
> > @@ -4880,22 +4878,25 @@ STATIC int
> > xlog_recover_process_intents(
> > struct xlog *log)
> > {
> > - struct xfs_defer_ops dfops;
> > + struct xfs_trans *tp;
> > struct xfs_ail_cursor cur;
> > struct xfs_log_item *lip;
> > struct xfs_ail *ailp;
> > - int error = 0;
> > + int error;
> > #if defined(DEBUG) || defined(XFS_WARN)
> > xfs_lsn_t last_lsn;
> > #endif
> >
> > + error = xfs_trans_alloc_empty(log->l_mp, &tp);
>
> Here's where we allocate the intent-placeholder transaction, so why
> isn't this named "itp" as well?
>
I only used itp where tp conflicted with a local transaction (the
contexts where we have to transfer state back and forth between two
transactions).
> I think I have a handle on what this patch does, though the variable
> naming itp/tp is a little confusing.
>
I have no real preference on the naming. I can call it parent_tp as
Christoph suggests and use that up and down the chain rather than only
in the contexts where both transactions exist if you think that is more
clear..?
Brian
> --D
>
> > + if (error)
> > + return error;
> > +
> > ailp = log->l_ailp;
> > spin_lock(&ailp->ail_lock);
> > lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
> > #if defined(DEBUG) || defined(XFS_WARN)
> > last_lsn = xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block);
> > #endif
> > - xfs_defer_init(NULL, &dfops);
> > while (lip != NULL) {
> > /*
> > * We're done when we see something other than an intent.
> > @@ -4930,12 +4931,10 @@ xlog_recover_process_intents(
> > error = xlog_recover_process_rui(log->l_mp, ailp, lip);
> > break;
> > case XFS_LI_CUI:
> > - error = xlog_recover_process_cui(log->l_mp, ailp, lip,
> > - &dfops);
> > + error = xlog_recover_process_cui(tp, ailp, lip);
> > break;
> > case XFS_LI_BUI:
> > - error = xlog_recover_process_bui(log->l_mp, ailp, lip,
> > - &dfops);
> > + error = xlog_recover_process_bui(tp, ailp, lip);
> > break;
> > }
> > if (error)
> > @@ -4945,10 +4944,9 @@ xlog_recover_process_intents(
> > out:
> > xfs_trans_ail_cursor_done(&cur);
> > spin_unlock(&ailp->ail_lock);
> > - if (error)
> > - __xfs_defer_cancel(&dfops);
> > - else
> > - error = xlog_finish_defer_ops(log->l_mp, &dfops);
> > + if (!error)
> > + error = xlog_finish_defer_ops(tp);
> > + xfs_trans_cancel(tp);
> >
> > return error;
> > }
> > diff --git a/fs/xfs/xfs_refcount_item.c b/fs/xfs/xfs_refcount_item.c
> > index d3582a06626f..d663ea1f4076 100644
> > --- a/fs/xfs/xfs_refcount_item.c
> > +++ b/fs/xfs/xfs_refcount_item.c
> > @@ -380,9 +380,8 @@ xfs_cud_init(
> > */
> > int
> > xfs_cui_recover(
> > - struct xfs_mount *mp,
> > - struct xfs_cui_log_item *cuip,
> > - struct xfs_defer_ops *dfops)
> > + struct xfs_trans *itp,
> > + struct xfs_cui_log_item *cuip)
> > {
> > int i;
> > int error = 0;
> > @@ -398,6 +397,7 @@ xfs_cui_recover(
> > xfs_extlen_t new_len;
> > struct xfs_bmbt_irec irec;
> > bool requeue_only = false;
> > + struct xfs_mount *mp = itp->t_mountp;
> >
> > ASSERT(!test_bit(XFS_CUI_RECOVERED, &cuip->cui_flags));
> >
> > @@ -457,7 +457,7 @@ xfs_cui_recover(
> > * finishes them on completion. Transfer current dfops state to this
> > * transaction and transfer the result back before we return.
> > */
> > - xfs_defer_move(tp->t_dfops, dfops);
> > + xfs_defer_move(tp->t_dfops, itp->t_dfops);
> > cudp = xfs_trans_get_cud(tp, cuip);
> >
> > for (i = 0; i < cuip->cui_format.cui_nextents; i++) {
> > @@ -522,13 +522,13 @@ xfs_cui_recover(
> >
> > xfs_refcount_finish_one_cleanup(tp, rcur, error);
> > set_bit(XFS_CUI_RECOVERED, &cuip->cui_flags);
> > - xfs_defer_move(dfops, tp->t_dfops);
> > + xfs_defer_move(itp->t_dfops, tp->t_dfops);
> > error = xfs_trans_commit(tp);
> > return error;
> >
> > abort_error:
> > xfs_refcount_finish_one_cleanup(tp, rcur, error);
> > - xfs_defer_move(dfops, tp->t_dfops);
> > + xfs_defer_move(itp->t_dfops, tp->t_dfops);
> > xfs_trans_cancel(tp);
> > return error;
> > }
> > diff --git a/fs/xfs/xfs_refcount_item.h b/fs/xfs/xfs_refcount_item.h
> > index dd830b69cd1e..98895da52c1f 100644
> > --- a/fs/xfs/xfs_refcount_item.h
> > +++ b/fs/xfs/xfs_refcount_item.h
> > @@ -82,7 +82,6 @@ struct xfs_cud_log_item *xfs_cud_init(struct xfs_mount *,
> > struct xfs_cui_log_item *);
> > void xfs_cui_item_free(struct xfs_cui_log_item *);
> > void xfs_cui_release(struct xfs_cui_log_item *);
> > -int xfs_cui_recover(struct xfs_mount *mp, struct xfs_cui_log_item *cuip,
> > - struct xfs_defer_ops *dfops);
> > +int xfs_cui_recover(struct xfs_trans *itp, struct xfs_cui_log_item *cuip);
> >
> > #endif /* __XFS_REFCOUNT_ITEM_H__ */
> > --
> > 2.17.1
> >
> > --
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