[PATCH 2/8] xfs: don't commit the first deferred transaction without intents

Dave Chinner
2022-04-27T02:23:10Z

From: Dave Chinner <dchinner@redhat.com>

If the first operation in a string of defer ops has no intents,
then there is no reason to commit it before running the first call
to xfs_defer_finish_one(). This allows the defer ops to be used
effectively for non-intent based operations without requiring an
unnecessary extra transaction commit when first called.

This fixes a regression in per-attribute modification transaction
count when delayed attributes are not being used.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/libxfs/xfs_defer.c | 29 +++++++++++++++++------------
1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
index 0805ade2d300..66b4555bda8e 100644
--- a/fs/xfs/libxfs/xfs_defer.c
+++ b/fs/xfs/libxfs/xfs_defer.c
@@ -186,7 +186,7 @@ static const struct xfs_defer_op_type *defer_op_types[] = {
[XFS_DEFER_OPS_TYPE_AGFL_FREE] = &xfs_agfl_free_defer_type,
};

-static void
+static bool
xfs_defer_create_intent(
struct xfs_trans *tp,
struct xfs_defer_pending *dfp,
@@ -197,6 +197,7 @@ xfs_defer_create_intent(
if (!dfp->dfp_intent)
dfp->dfp_intent = ops->create_intent(tp, &dfp->dfp_work,
dfp->dfp_count, sort);
+ return dfp->dfp_intent;
}

/*
@@ -204,16 +205,18 @@ xfs_defer_create_intent(
* associated extents, then add the entire intake list to the end of
* the pending list.
*/
-STATIC void
+static bool
xfs_defer_create_intents(
struct xfs_trans *tp)
{
struct xfs_defer_pending *dfp;
+ bool ret = false;

list_for_each_entry(dfp, &tp->t_dfops, dfp_list) {
trace_xfs_defer_create_intent(tp->t_mountp, dfp);
- xfs_defer_create_intent(tp, dfp, true);
+ ret |= xfs_defer_create_intent(tp, dfp, true);
}
+ return ret;
}

/* Abort all the intents that were committed. */
@@ -487,7 +490,7 @@ int
xfs_defer_finish_noroll(
struct xfs_trans **tp)
{
- struct xfs_defer_pending *dfp;
+ struct xfs_defer_pending *dfp = NULL;
int error = 0;
LIST_HEAD(dop_pending);

@@ -506,17 +509,19 @@ xfs_defer_finish_noroll(
* of time that any one intent item can stick around in memory,
* pinning the log tail.
*/
- xfs_defer_create_intents(*tp);
+ bool has_intents = xfs_defer_create_intents(*tp);
list_splice_init(&(*tp)->t_dfops, &dop_pending);

- error = xfs_defer_trans_roll(tp);
- if (error)
- goto out_shutdown;
+ if (has_intents || dfp) {
+ error = xfs_defer_trans_roll(tp);
+ if (error)
+ goto out_shutdown;

- /* Possibly relog intent items to keep the log moving. */
- error = xfs_defer_relog(tp, &dop_pending);
- if (error)
- goto out_shutdown;
+ /* Possibly relog intent items to keep the log moving. */
+ error = xfs_defer_relog(tp, &dop_pending);
+ if (error)
+ goto out_shutdown;
+ }

dfp = list_first_entry(&dop_pending, struct xfs_defer_pending,
dfp_list);
--
2.35.1