The commit fa2bbff7b0b4 breaks the LVM2 test shell/integrity-caching.sh,
so let's revert it.
sysrq: Show Blocked State
task:lvm state:D stack:0 pid:8275 tgid:8275 ppid:1373
flags:0x00000002
Call Trace:
<TASK>
__schedule+0x228/0x570
? __percpu_ref_switch_mode+0xb7/0x1b0
schedule+0x29/0xa0
mddev_suspend+0xec/0x1a0 [md_mod]
? housekeeping_test_cpu+0x30/0x30
dm_table_postsuspend_targets+0x34/0x50 [dm_mod]
__dm_destroy+0x1c5/0x1e0 [dm_mod]
? table_clear+0xa0/0xa0 [dm_mod]
dev_remove+0xd4/0x110 [dm_mod]
ctl_ioctl+0x2e1/0x570 [dm_mod]
dm_ctl_ioctl+0x5/0x10 [dm_mod]
__x64_sys_ioctl+0x85/0xa0
do_syscall_64+0x5d/0x1a0
entry_SYSCALL_64_after_hwframe+0x46/0x4e
Signed-off-by: Mikulas Patocka <mpato...@redhat.com>
Fixes: fa2bbff7b0b4 ("md: synchronize flush io with array reconfiguration")
---
drivers/md/md.c | 21 ++++++---------------
1 file changed, 6 insertions(+), 15 deletions(-)
Index: linux-2.6/drivers/md/md.c
===================================================================
--- linux-2.6.orig/drivers/md/md.c
+++ linux-2.6/drivers/md/md.c
@@ -543,9 +543,6 @@ static void md_end_flush(struct bio *bio
rdev_dec_pending(rdev, mddev);
if (atomic_dec_and_test(&mddev->flush_pending)) {
- /* The pair is percpu_ref_get() from md_flush_request() */
- percpu_ref_put(&mddev->active_io);
-
/* The pre-request flush has finished */
queue_work(md_wq, &mddev->flush_work);
}
@@ -565,7 +562,12 @@ static void submit_flushes(struct work_s
rdev_for_each_rcu(rdev, mddev)
if (rdev->raid_disk >= 0 &&
!test_bit(Faulty, &rdev->flags)) {
+ /* Take two references, one is dropped
+ * when request finishes, one after
+ * we reclaim rcu_read_lock
+ */
struct bio *bi;
+ atomic_inc(&rdev->nr_pending);
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
@@ -577,6 +579,7 @@ static void submit_flushes(struct work_s
atomic_inc(&mddev->flush_pending);
submit_bio(bi);
rcu_read_lock();
+ rdev_dec_pending(rdev, mddev);
}
rcu_read_unlock();
if (atomic_dec_and_test(&mddev->flush_pending))
@@ -629,18 +632,6 @@ bool md_flush_request(struct mddev *mdde
/* new request after previous flush is completed */
if (ktime_after(req_start, mddev->prev_flush_start)) {
WARN_ON(mddev->flush_bio);
- /*
- * Grab a reference to make sure mddev_suspend() will wait for
- * this flush to be done.
- *
- * md_flush_reqeust() is called under md_handle_request() and
- * 'active_io' is already grabbed, hence percpu_ref_is_zero()
- * won't pass, percpu_ref_tryget_live() can't be used because
- * percpu_ref_kill() can be called by mddev_suspend()
- * concurrently.
- */
- WARN_ON(percpu_ref_is_zero(&mddev->active_io));
- percpu_ref_get(&mddev->active_io);
mddev->flush_bio = bio;
bio = NULL;
}
