p71924506
/
linux_old1
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

dm cache policy smq: handle races with queuing background_work 

The background_tracker holds a set of promotions/demotions that the
cache policy wishes the core target to implement.

When adding a new operation to the tracker it's possible that an
operation on the same block is already present (but in practise this
doesn't appear to be happening).  Catch these situations and do the
appropriate cleanup.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Joe Thornber 2017-11-08 05:56:11 -05:00 committed by Mike Snitzer
parent 2339784490
commit 1e72a8e809
1 changed files with 14 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/md/dm-cache-policy-smq.c
View File

@ -1174,12 +1174,16 @@ static void queue_writeback(struct smq_policy *mq)
work.cblock = infer_cblock(mq, e);
r = btracker_queue(mq->bg_work, &work, NULL);
WARN_ON_ONCE(r); // FIXME: finish, I think we have to get rid of this race.
if (r) {
clear_pending(mq, e);
q_push_front(&mq->dirty, e);
}
}
}
static void queue_demotion(struct smq_policy *mq)
{
int r;
struct policy_work work;
struct entry *e;
@ -1199,12 +1203,17 @@ static void queue_demotion(struct smq_policy *mq)
work.op = POLICY_DEMOTE;
work.oblock = e->oblock;
work.cblock = infer_cblock(mq, e);
btracker_queue(mq->bg_work, &work, NULL);
r = btracker_queue(mq->bg_work, &work, NULL);
if (r) {
clear_pending(mq, e);
q_push_front(&mq->clean, e);
}
}
static void queue_promotion(struct smq_policy *mq, dm_oblock_t oblock,
struct policy_work **workp)
{
int r;
struct entry *e;
struct policy_work work;
@ -1234,7 +1243,9 @@ static void queue_promotion(struct smq_policy *mq, dm_oblock_t oblock,
work.op = POLICY_PROMOTE;
work.oblock = oblock;
work.cblock = infer_cblock(mq, e);
btracker_queue(mq->bg_work, &work, workp);
r = btracker_queue(mq->bg_work, &work, workp);
if (r)
free_entry(&mq->cache_alloc, e);
}
/*----------------------------------------------------------------*/