From: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
To: linux-raid@vger.kernel.org
Cc: song@kernel.org, Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Subject: [PATCH 1/3] raid5: call clear_batch_ready before set STRIPE_ACTIVE
Date: Tue, 16 Jun 2020 11:25:50 +0200 [thread overview]
Message-ID: <20200616092552.1754-1-guoqing.jiang@cloud.ionos.com> (raw)
We tried to only put the head sh of batch list to handle_list, then the
handle_stripe doesn't handle other members in the batch list. However,
we still got the calltrace in break_stripe_batch_list.
[593764.644269] stripe state: 2003
kernel: [593764.644299] ------------[ cut here ]------------
kernel: [593764.644308] WARNING: CPU: 12 PID: 856 at drivers/md/raid5.c:4625 break_stripe_batch_list+0x203/0x240 [raid456]
[...]
kernel: [593764.644363] Call Trace:
kernel: [593764.644370] handle_stripe+0x907/0x20c0 [raid456]
kernel: [593764.644376] ? __wake_up_common_lock+0x89/0xc0
kernel: [593764.644379] handle_active_stripes.isra.57+0x35f/0x570 [raid456]
kernel: [593764.644382] ? raid5_wakeup_stripe_thread+0x96/0x1f0 [raid456]
kernel: [593764.644385] raid5d+0x480/0x6a0 [raid456]
kernel: [593764.644390] ? md_thread+0x11f/0x160
kernel: [593764.644392] md_thread+0x11f/0x160
kernel: [593764.644394] ? wait_woken+0x80/0x80
kernel: [593764.644396] kthread+0xfc/0x130
kernel: [593764.644398] ? find_pers+0x70/0x70
kernel: [593764.644399] ? kthread_create_on_node+0x70/0x70
kernel: [593764.644401] ret_from_fork+0x1f/0x30
As we can see, the stripe was set with STRIPE_ACTIVE and STRIPE_HANDLE,
and only handle_stripe could set those flags then return. And since the
stipe was already in the batch list, we need to return earlier before
set the two flags.
And after dig a little about git history especially commit 3664847d95e6
("md/raid5: fix a race condition in stripe batch"), it seems the batched
stipe still could be handled by handle_stipe, then handle_stipe needs to
return earlier if clear_batch_ready to return true.
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
---
Another alternative would be just not warn if STRIPE_ACTIVE is valid for
the batched list.
What do you think?
Thanks,
Guoqing
drivers/md/raid5.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ab8067f9ce8c..a35332364f07 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4682,6 +4682,16 @@ static void handle_stripe(struct stripe_head *sh)
struct r5dev *pdev, *qdev;
clear_bit(STRIPE_HANDLE, &sh->state);
+
+ /*
+ * handle_stripe should not continue handle the batched stripe, only
+ * the head of batch list or lone stripe can continue. Otherwise we
+ * could see break_stripe_batch_list warns about the STRIPE_ACTIVE
+ * is set for the batched stripe.
+ */
+ if (clear_batch_ready(sh))
+ return;
+
if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
/* already being handled, ensure it gets handled
* again when current action finishes */
@@ -4689,11 +4699,6 @@ static void handle_stripe(struct stripe_head *sh)
return;
}
- if (clear_batch_ready(sh) ) {
- clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
- return;
- }
-
if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
break_stripe_batch_list(sh, 0);
--
2.17.1
next reply other threads:[~2020-06-16 9:25 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-16 9:25 Guoqing Jiang [this message]
2020-06-16 9:25 ` [PATCH 2/3] raid5: put the comment of clear_batch_ready to the right place Guoqing Jiang
2020-06-16 9:25 ` [PATCH 3/3] raid5: remove the meaningless check in raid5_make_request Guoqing Jiang
2020-06-19 14:16 ` [PATCH 1/3] raid5: call clear_batch_ready before set STRIPE_ACTIVE Guoqing Jiang
2020-06-23 23:58 ` Song Liu
2020-06-25 9:22 ` Guoqing Jiang
2020-06-26 0:16 ` Song Liu
2020-07-16 7:44 ` Guoqing Jiang
2020-07-16 17:32 ` Song Liu
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