Test case #46 in t/zbd/test-zbd-support fails when it is repeated
hundreds of times on null_blk zoned devices. The test case uses libaio
IO engine to run 8 random write jobs on 4 sequential write required
zones. When all of the 4 zones get almost full but still open for
in-flight writes, the helper function zbd_convert_to_open_zone() fails
to get an opened zone for next write. This results in unexpected job
termination.
To avoid the unexpected job termination, retry the steps in
zbd_convert_to_open_zone(). Before retry, call io_u_quiesce() to ensure
that the in-flight writes get completed.
To prevent infinite loop by the retry, retry only when any IOs are
in-flight or in-flight IOs get completed. To check in-flight IO count of
all jobs, add a new helper function any_io_in_flight().
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
---
zbd.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/zbd.c b/zbd.c
index 64415d2b..c0b0b81c 100644
--- a/zbd.c
+++ b/zbd.c
@@ -1204,6 +1204,19 @@ static uint32_t pick_random_zone_idx(const struct fio_file *f,
f->io_size;
}
+static bool any_io_in_flight(void)
+{
+ struct thread_data *td;
+ int i;
+
+ for_each_td(td, i) {
+ if (td->io_u_in_flight)
+ return true;
+ }
+
+ return false;
+}
+
/*
* Modify the offset of an I/O unit that does not refer to an open zone such
* that it refers to an open zone. Close an open zone and open a new zone if
@@ -1223,6 +1236,8 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
uint32_t zone_idx, new_zone_idx;
int i;
bool wait_zone_close;
+ bool in_flight;
+ bool should_retry = true;
assert(is_valid_offset(f, io_u->offset));
@@ -1337,6 +1352,7 @@ open_other_zone:
io_u_quiesce(td);
}
+retry:
/* Zone 'z' is full, so try to open a new zone. */
for (i = f->io_size / zbdi->zone_size; i > 0; i--) {
zone_idx++;
@@ -1376,6 +1392,24 @@ open_other_zone:
goto out;
pthread_mutex_lock(&zbdi->mutex);
}
+
+ /*
+ * When any I/O is in-flight or when all I/Os in-flight get completed,
+ * the I/Os might have closed zones then retry the steps to open a zone.
+ * Before retry, call io_u_quiesce() to complete in-flight writes.
+ */
+ in_flight = any_io_in_flight();
+ if (in_flight || should_retry) {
+ dprint(FD_ZBD, "%s(%s): wait zone close and retry open zones\n",
+ __func__, f->file_name);
+ pthread_mutex_unlock(&zbdi->mutex);
+ zone_unlock(z);
+ io_u_quiesce(td);
+ zone_lock(td, f, z);
+ should_retry = in_flight;
+ goto retry;
+ }
+
pthread_mutex_unlock(&zbdi->mutex);
zone_unlock(z);
dprint(FD_ZBD, "%s(%s): did not open another zone\n", __func__,
--
2.31.1
