xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

md: always hold reconfig_mutex when calling mddev_suspend()

Browse Source 
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>
This commit is contained in:
NeilBrown
2017-10-19 12:17:16 +11:00
committed by Shaohua Li
parent 230b55fa8d
commit 4d5324f760
3 changed files with 24 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/md/dm-raid.c
View File

@@ -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 = {