From: NeilBrown <neilb@suse.com>
To: Shaohua Li <shli@kernel.org>
Cc: linux-raid@vger.kernel.org, hch@lst.de
Subject: [md PATCH 11/15] md/raid5: don't test ->writes_pending in raid5_remove_disk
Date: Wed, 15 Mar 2017 14:05:14 +1100 [thread overview]
Message-ID: <148954711407.18641.13319777867112915321.stgit@noble> (raw)
In-Reply-To: <148954692173.18641.1294690639716682540.stgit@noble>
This test on ->writes_pending cannot be safe as the counter
can be incremented at any moment and cannot be locked against.
Change it to test conf->active_stripes, which at least
can be locked against. More changes are still needed.
A future patch will change ->writes_pending, and testing it here will
be very inconvenient.
Signed-off-by: NeilBrown <neilb@suse.com>
---
drivers/md/raid5.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 4e906e5903e8..5eb3764bafd3 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7528,9 +7528,12 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
/*
* we can't wait pending write here, as this is called in
* raid5d, wait will deadlock.
+ * neilb: there is no locking about new writes here,
+ * so this cannot be safe.
*/
- if (atomic_read(&mddev->writes_pending))
+ if (atomic_read(&conf->active_stripes)) {
return -EBUSY;
+ }
log_exit(conf);
return 0;
}
next prev parent reply other threads:[~2017-03-15 3:05 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-15 3:05 [md PATCH 00/15 v2] remove all abuse of bi_phys_segments NeilBrown
2017-03-15 3:05 ` [md PATCH 03/15] md/raid5: call bio_endio() directly rather than queueing for later NeilBrown
2017-03-15 3:05 ` [md PATCH 02/15] md/raid5: simplfy delaying of writes while metadata is updated NeilBrown
2017-03-15 23:03 ` Shaohua Li
2017-03-16 2:45 ` NeilBrown
2017-03-22 1:40 ` Fix bug in " NeilBrown
2017-03-22 2:29 ` REALLY " NeilBrown
2017-03-22 2:35 ` NeilBrown
2017-03-23 2:22 ` Shaohua Li
2017-03-15 3:05 ` [md PATCH 01/15] md/raid5: use md_write_start to count stripes, not bios NeilBrown
2017-03-15 3:05 ` [md PATCH 04/15] block: trace completion of all bios NeilBrown
2017-03-15 3:05 ` [md PATCH 07/15] Revert "md/raid5: limit request size according to implementation limits" NeilBrown
2017-03-15 3:05 ` [md PATCH 06/15] md/raid5: remove over-loading of ->bi_phys_segments NeilBrown
2017-03-15 3:05 ` [md PATCH 05/15] md/raid5: use bio_inc_remaining() instead of repurposing bi_phys_segments as a counter NeilBrown
2017-03-15 3:05 ` [md PATCH 09/15] md/raid10: stop using bi_phys_segments NeilBrown
2017-03-15 3:05 ` [md PATCH 08/15] md/raid1, raid10: move rXbio accounting closer to allocation NeilBrown
2017-03-15 3:05 ` [md PATCH 15/15] MD: use per-cpu counter for writes_pending NeilBrown
2017-03-16 1:05 ` Shaohua Li
2017-03-16 2:57 ` NeilBrown
2017-03-22 1:55 ` Improvement for " NeilBrown
2017-03-22 2:34 ` IMPROVEMENT for " NeilBrown
2017-03-15 3:05 ` [md PATCH 12/15] md: factor out set_in_sync() NeilBrown
2017-03-15 3:05 ` [md PATCH 14/15] percpu-refcount: support synchronous switch to atomic mode NeilBrown
2017-03-15 3:05 ` [md PATCH 13/15] md: close a race with setting mddev->in_sync NeilBrown
2017-03-15 3:05 ` NeilBrown [this message]
2017-03-15 3:05 ` [md PATCH 10/15] md/raid1: stop using bi_phys_segment NeilBrown
2017-03-16 0:13 ` Shaohua Li
2017-03-16 2:49 ` NeilBrown
2017-03-16 3:36 ` Shaohua Li
2017-03-22 1:41 ` Fix bugs in " NeilBrown
2017-03-16 1:12 ` [md PATCH 00/15 v2] remove all abuse of bi_phys_segments Shaohua Li
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