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authorNeilBrown <neilb@suse.com>2017-10-19 12:17:16 +1100
committerShaohua Li <shli@fb.com>2017-11-01 21:32:18 -0700
commit4d5324f760aacaefeb721b172aa14bf66045c332 (patch)
tree4115e3a5b37b7890c402d07ce551648b93f63844 /drivers/md/dm-raid.c
parent230b55fa8d64007339319539f8f8e68114d08529 (diff)
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md: always hold reconfig_mutex when calling mddev_suspend()
Most often mddev_suspend() is called with reconfig_mutex held. Make this a requirement in preparation a subsequent patch. Also require reconfig_mutex to be held for mddev_resume(), partly for symmetry and partly to guarantee no races with incr/decr of mddev->suspend. Taking the mutex in r5c_disable_writeback_async() is a little tricky as this is called from a work queue via log->disable_writeback_work, and flush_work() is called on that while holding ->reconfig_mutex. If the work item hasn't run before flush_work() is called, the work function will not be able to get the mutex. So we use mddev_trylock() inside the wait_event() call, and have that abort when conf->log is set to NULL, which happens before flush_work() is called. We wait in mddev->sb_wait and ensure this is woken when any of the conditions change. This requires waking mddev->sb_wait in mddev_unlock(). This is only like to trigger extra wake_ups of threads that needn't be woken when metadata is being written, and that doesn't happen often enough that the cost would be noticeable. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/dm-raid.c')
-rw-r--r--drivers/md/dm-raid.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 252770696a05..8b1d93114f40 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -3628,8 +3628,11 @@ static void raid_postsuspend(struct dm_target *ti)
{
struct raid_set *rs = ti->private;
- if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags))
+ if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
+ mddev_lock_nointr(&rs->md);
mddev_suspend(&rs->md);
+ mddev_unlock(&rs->md);
+ }
rs->md.ro = 1;
}
@@ -3886,8 +3889,11 @@ static void raid_resume(struct dm_target *ti)
if (!(rs->ctr_flags & RESUME_STAY_FROZEN_FLAGS))
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
- if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags))
+ if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
+ mddev_lock_nointr(mddev);
mddev_resume(mddev);
+ mddev_unlock(mddev);
+ }
}
static struct target_type raid_target = {