2 files changed, 17 insertions, 4 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index ac0fa10f8fa5..71da5111120c 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1161,7 +1161,7 @@ static int __make_request(struct request_queue *q, struct bio *bio)
         const unsigned int ff = bio->bi_rw & REQ_FAILFAST_MASK;
         int rw_flags;
 
-        if (bio_rw_flagged(bio, BIO_RW_BARRIER) && bio_has_data(bio) &&
+        if (bio_rw_flagged(bio, BIO_RW_BARRIER) &&
             (q->next_ordered == QUEUE_ORDERED_NONE)) {
                 bio_endio(bio, -EOPNOTSUPP);
                 return 0;
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 069a61017c02..aa1e9535e358 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -196,6 +196,7 @@ enum cfqq_state_flags {
         CFQ_CFQQ_FLAG_slice_new,        /* no requests dispatched in slice */
         CFQ_CFQQ_FLAG_sync,             /* synchronous queue */
         CFQ_CFQQ_FLAG_coop,             /* has done a coop jump of the queue */
+        CFQ_CFQQ_FLAG_coop_preempt,     /* coop preempt */
 };
 
 #define CFQ_CFQQ_FNS(name)                                              \
@@ -222,6 +223,7 @@ CFQ_CFQQ_FNS(prio_changed);
 CFQ_CFQQ_FNS(slice_new);
 CFQ_CFQQ_FNS(sync);
 CFQ_CFQQ_FNS(coop);
+CFQ_CFQQ_FNS(coop_preempt);
 #undef CFQ_CFQQ_FNS
 
 #define cfq_log_cfqq(cfqd, cfqq, fmt, args...)  \
@@ -945,10 +947,13 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd,
 {
         if (!cfqq) {
                 cfqq = cfq_get_next_queue(cfqd);
-                if (cfqq)
+                if (cfqq && !cfq_cfqq_coop_preempt(cfqq))
                         cfq_clear_cfqq_coop(cfqq);
         }
 
+        if (cfqq)
+                cfq_clear_cfqq_coop_preempt(cfqq);
+
         __cfq_set_active_queue(cfqd, cfqq);
         return cfqq;
 }
@@ -2051,7 +2056,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
          * it's a metadata request and the current queue is doing regular IO.
          */
         if (rq_is_meta(rq) && !cfqq->meta_pending)
-                return false;
+                return true;
 
         /*
          * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
@@ -2066,8 +2071,16 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
          * if this request is as-good as one we would expect from the
          * current cfqq, let it preempt
          */
-        if (cfq_rq_close(cfqd, rq))
+        if (cfq_rq_close(cfqd, rq) && (!cfq_cfqq_coop(new_cfqq) ||
+            cfqd->busy_queues == 1)) {
+                /*
+                 * Mark new queue coop_preempt, so its coop flag will not be
+                 * cleared when new queue gets scheduled at the very first time
+                 */
+                cfq_mark_cfqq_coop_preempt(new_cfqq);
+                cfq_mark_cfqq_coop(new_cfqq);
                 return true;
+        }
 
         return false;
 }