On Fri, Feb 23, 2024 at 11:06 AM Yu Kuai [off-list ref] wrote:

Hi,

在 2024/02/20 23:30, Xiao Ni 写道:

quoted

If all flush bios finish fast, it doesn't decrease active_io. And it will
stuck when stopping array.

This can be reproduced by lvm2 test shell/integrity-caching.sh.
But it can't reproduce 100%.

Fixes: fa2bbff7b0b4 ("md: synchronize flush io with array reconfiguration")
Signed-off-by: Xiao Ni <redacted>

Same patch is already applied:

855678ed8534 md: Fix missing release of 'active_io' for flush

Thanks for the information. I used Linus's tree so I missed this one.

Regards
Xiao

Thanks,
Kuai

quoted

---
  drivers/md/md.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 77e3af7cf6bb..a41bed286fd2 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c

@@ -579,8 +579,12 @@ static void submit_flushes(struct work_struct *ws)
                      rcu_read_lock();
              }
      rcu_read_unlock();
-     if (atomic_dec_and_test(&mddev->flush_pending))
+     if (atomic_dec_and_test(&mddev->flush_pending)) {
+             /* The pair is percpu_ref_get() from md_flush_request() */
+             percpu_ref_put(&mddev->active_io);
+
              queue_work(md_wq, &mddev->flush_work);
+     }
  }

  static void md_submit_flush_data(struct work_struct *ws)