21 files changed, 92 insertions, 78 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index bcaf16ee6ad1..b596e54ddd71 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -785,10 +785,10 @@ static int blkio_policy_parse_and_set(char *buf,
 {
         char *s[4], *p, *major_s = NULL, *minor_s = NULL;
         int ret;
-        unsigned long major, minor, temp;
+        unsigned long major, minor;
         int i = 0;
         dev_t dev;
-        u64 bps, iops;
+        u64 temp;
 
         memset(s, 0, sizeof(s));
 
@@ -826,20 +826,23 @@ static int blkio_policy_parse_and_set(char *buf,
 
         dev = MKDEV(major, minor);
 
-        ret = blkio_check_dev_num(dev);
+        ret = strict_strtoull(s[1], 10, &temp);
         if (ret)
-                return ret;
+                return -EINVAL;
 
-        newpn->dev = dev;
+        /* For rule removal, do not check for device presence. */
+        if (temp) {
+                ret = blkio_check_dev_num(dev);
+                if (ret)
+                        return ret;
+        }
 
-        if (s[1] == NULL)
-                return -EINVAL;
+        newpn->dev = dev;
 
         switch (plid) {
         case BLKIO_POLICY_PROP:
-                ret = strict_strtoul(s[1], 10, &temp);
-                if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||
-                        temp > BLKIO_WEIGHT_MAX)
+                if ((temp < BLKIO_WEIGHT_MIN && temp > 0) ||
+                     temp > BLKIO_WEIGHT_MAX)
                         return -EINVAL;
 
                 newpn->plid = plid;
@@ -850,26 +853,18 @@ static int blkio_policy_parse_and_set(char *buf,
                 switch(fileid) {
                 case BLKIO_THROTL_read_bps_device:
                 case BLKIO_THROTL_write_bps_device:
-                        ret = strict_strtoull(s[1], 10, &bps);
-                        if (ret)
-                                return -EINVAL;
-
                         newpn->plid = plid;
                         newpn->fileid = fileid;
-                        newpn->val.bps = bps;
+                        newpn->val.bps = temp;
                         break;
                 case BLKIO_THROTL_read_iops_device:
                 case BLKIO_THROTL_write_iops_device:
-                        ret = strict_strtoull(s[1], 10, &iops);
-                        if (ret)
-                                return -EINVAL;
-
-                        if (iops > THROTL_IOPS_MAX)
+                        if (temp > THROTL_IOPS_MAX)
                                 return -EINVAL;
 
                         newpn->plid = plid;
                         newpn->fileid = fileid;
-                        newpn->val.iops = (unsigned int)iops;
+                        newpn->val.iops = (unsigned int)temp;
                         break;
                 }
                 break;
diff --git a/block/blk-core.c b/block/blk-core.c
index 90e1ffdeb415..b2ed78afd9f0 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1167,7 +1167,7 @@ static bool bio_attempt_front_merge(struct request_queue *q,
  * true if merge was successful, otherwise false.
  */
 static bool attempt_plug_merge(struct task_struct *tsk, struct request_queue *q,
-                               struct bio *bio)
+                               struct bio *bio, unsigned int *request_count)
 {
         struct blk_plug *plug;
         struct request *rq;
@@ -1176,10 +1176,13 @@ static bool attempt_plug_merge(struct task_struct *tsk, struct request_queue *q,
         plug = tsk->plug;
         if (!plug)
                 goto out;
+        *request_count = 0;
 
         list_for_each_entry_reverse(rq, &plug->list, queuelist) {
                 int el_ret;
 
+                (*request_count)++;
+
                 if (rq->q != q)
                         continue;
 
@@ -1219,6 +1222,7 @@ static int __make_request(struct request_queue *q, struct bio *bio)
         struct blk_plug *plug;
         int el_ret, rw_flags, where = ELEVATOR_INSERT_SORT;
         struct request *req;
+        unsigned int request_count = 0;
 
         /*
          * low level driver can indicate that it wants pages above a
@@ -1237,7 +1241,7 @@ static int __make_request(struct request_queue *q, struct bio *bio)
          * Check if we can merge with the plugged list before grabbing
          * any locks.
          */
-        if (attempt_plug_merge(current, q, bio))
+        if (attempt_plug_merge(current, q, bio, &request_count))
                 goto out;
 
         spin_lock_irq(q->queue_lock);
@@ -1302,11 +1306,10 @@ get_rq:
                         if (__rq->q != q)
                                 plug->should_sort = 1;
                 }
+                if (request_count >= BLK_MAX_REQUEST_COUNT)
+                        blk_flush_plug_list(plug, false);
                 list_add_tail(&req->queuelist, &plug->list);
-                plug->count++;
                 drive_stat_acct(req, 1);
-                if (plug->count >= BLK_MAX_REQUEST_COUNT)
-                        blk_flush_plug_list(plug, false);
         } else {
                 spin_lock_irq(q->queue_lock);
                 add_acct_request(q, req, where);
@@ -2634,7 +2637,6 @@ void blk_start_plug(struct blk_plug *plug)
         INIT_LIST_HEAD(&plug->list);
         INIT_LIST_HEAD(&plug->cb_list);
         plug->should_sort = 0;
-        plug->count = 0;
 
         /*
          * If this is a nested plug, don't actually assign it. It will be
@@ -2718,7 +2720,6 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
                 return;
 
         list_splice_init(&plug->list, &list);
-        plug->count = 0;
 
         if (plug->should_sort) {
                 list_sort(NULL, &list, plug_rq_cmp);
diff --git a/block/blk-softirq.c b/block/blk-softirq.c
index 58340d0cb23a..1366a89d8e66 100644
--- a/block/blk-softirq.c
+++ b/block/blk-softirq.c
@@ -115,7 +115,7 @@ void __blk_complete_request(struct request *req)
         /*
          * Select completion CPU
          */
-        if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) && req->cpu != -1) {
+        if (req->cpu != -1) {
                 ccpu = req->cpu;
                 if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags)) {
                         ccpu = blk_cpu_to_group(ccpu);
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 0ee17b5e7fb6..e681805cdb47 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -258,11 +258,13 @@ queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
 
         ret = queue_var_store(&val, page, count);
         spin_lock_irq(q->queue_lock);
-        if (val) {
+        if (val == 2) {
                 queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
-                if (val == 2)
-                        queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
-        } else {
+                queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
+        } else if (val == 1) {
+                queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
+                queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
+        } else if (val == 0) {
                 queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
                 queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
         }
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index a33bd4377c61..16ace89613bc 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -130,8 +130,8 @@ struct cfq_queue {
         unsigned long slice_end;
         long slice_resid;
 
-        /* pending metadata requests */
-        int meta_pending;
+        /* pending priority requests */
+        int prio_pending;
         /* number of requests that are on the dispatch list or inside driver */
         int dispatched;
 
@@ -684,8 +684,8 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2,
         if (rq_is_sync(rq1) != rq_is_sync(rq2))
                 return rq_is_sync(rq1) ? rq1 : rq2;
 
-        if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_META)
-                return rq1->cmd_flags & REQ_META ? rq1 : rq2;
+        if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO)
+                return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2;
 
         s1 = blk_rq_pos(rq1);
         s2 = blk_rq_pos(rq2);
@@ -1612,9 +1612,9 @@ static void cfq_remove_request(struct request *rq)
         cfqq->cfqd->rq_queued--;
         cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg,
                                         rq_data_dir(rq), rq_is_sync(rq));
-        if (rq->cmd_flags & REQ_META) {
-                WARN_ON(!cfqq->meta_pending);
-                cfqq->meta_pending--;
+        if (rq->cmd_flags & REQ_PRIO) {
+                WARN_ON(!cfqq->prio_pending);
+                cfqq->prio_pending--;
         }
 }
 
@@ -3372,7 +3372,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
          * So both queues are sync. Let the new request get disk time if
          * it's a metadata request and the current queue is doing regular IO.
          */
-        if ((rq->cmd_flags & REQ_META) && !cfqq->meta_pending)
+        if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending)
                 return true;
 
         /*
@@ -3439,8 +3439,8 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
         struct cfq_io_context *cic = RQ_CIC(rq);
 
         cfqd->rq_queued++;
-        if (rq->cmd_flags & REQ_META)
-                cfqq->meta_pending++;
+        if (rq->cmd_flags & REQ_PRIO)
+                cfqq->prio_pending++;
 
         cfq_update_io_thinktime(cfqd, cfqq, cic);
         cfq_update_io_seektime(cfqd, cfqq, rq);
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 98de8f418676..9955a53733b2 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4250,7 +4250,7 @@ static int __init floppy_init(void)
         use_virtual_dma = can_use_virtual_dma & 1;
         fdc_state[0].address = FDC1;
         if (fdc_state[0].address == -1) {
-                del_timer(&fd_timeout);
+                del_timer_sync(&fd_timeout);
                 err = -ENODEV;
                 goto out_unreg_region;
         }
@@ -4261,7 +4261,7 @@ static int __init floppy_init(void)
         fdc = 0;                /* reset fdc in case of unexpected interrupt */
         err = floppy_grab_irq_and_dma();
         if (err) {
-                del_timer(&fd_timeout);
+                del_timer_sync(&fd_timeout);
                 err = -EBUSY;
                 goto out_unreg_region;
         }
@@ -4318,7 +4318,7 @@ static int __init floppy_init(void)
                 user_reset_fdc(-1, FD_RESET_ALWAYS, false);
         }
         fdc = 0;
-        del_timer(&fd_timeout);
+        del_timer_sync(&fd_timeout);
         current_drive = 0;
         initialized = true;
         if (have_no_fdc) {
@@ -4368,7 +4368,7 @@ out_unreg_blkdev:
         unregister_blkdev(FLOPPY_MAJOR, "fd");
 out_put_disk:
         while (dr--) {
-                del_timer(&motor_off_timer[dr]);
+                del_timer_sync(&motor_off_timer[dr]);
                 if (disks[dr]->queue)
                         blk_cleanup_queue(disks[dr]->queue);
                 put_disk(disks[dr]);
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index 9e40b283a468..00c57c90e2d6 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -46,7 +46,7 @@
 
 #define DRV_PFX "xen-blkback:"
 #define DPRINTK(fmt, args...)                           \
-        pr_debug(DRV_PFX "(%s:%d) " fmt ".\n",  \
+        pr_debug(DRV_PFX "(%s:%d) " fmt ".\n",          \
                  __func__, __LINE__, ##args)
 
 
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 3f129b45451a..5fd2010f7d2b 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -590,7 +590,7 @@ static void frontend_changed(struct xenbus_device *dev,
 
                 /*
                  * Enforce precondition before potential leak point.
-                 * blkif_disconnect() is idempotent.
+                 * xen_blkif_disconnect() is idempotent.
                  */
                 xen_blkif_disconnect(be->blkif);
 
@@ -601,17 +601,17 @@ static void frontend_changed(struct xenbus_device *dev,
                 break;
 
         case XenbusStateClosing:
-                xen_blkif_disconnect(be->blkif);
                 xenbus_switch_state(dev, XenbusStateClosing);
                 break;
 
         case XenbusStateClosed:
+                xen_blkif_disconnect(be->blkif);
                 xenbus_switch_state(dev, XenbusStateClosed);
                 if (xenbus_dev_is_online(dev))
                         break;
                 /* fall through if not online */
         case XenbusStateUnknown:
-                /* implies blkif_disconnect() via blkback_remove() */
+                /* implies xen_blkif_disconnect() via xen_blkbk_remove() */
                 device_unregister(&dev->dev);
                 break;
 
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 1ff5486213fb..4c1a648d00fc 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -926,6 +926,9 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
         /*
          * Reliable writes are used to implement Forced Unit Access and
          * REQ_META accesses, and are supported only on MMCs.
+         *
+         * XXX: this really needs a good explanation of why REQ_META
+         * is treated special.
          */
         bool do_rel_wr = ((req->cmd_flags & REQ_FUA) ||
                           (req->cmd_flags & REQ_META)) &&
diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index 04da6acde85d..12661e1deedd 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -1134,7 +1134,7 @@ struct buffer_head *ext3_bread(handle_t *handle, struct inode *inode,
                 return bh;
         if (buffer_uptodate(bh))
                 return bh;
-        ll_rw_block(READ_META, 1, &bh);
+        ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
         wait_on_buffer(bh);
         if (buffer_uptodate(bh))
                 return bh;
@@ -2807,7 +2807,7 @@ make_io:
                 trace_ext3_load_inode(inode);
                 get_bh(bh);
                 bh->b_end_io = end_buffer_read_sync;
-                submit_bh(READ_META, bh);
+                submit_bh(READ | REQ_META | REQ_PRIO, bh);
                 wait_on_buffer(bh);
                 if (!buffer_uptodate(bh)) {
                         ext3_error(inode->i_sb, "ext3_get_inode_loc",
diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
index 5571708b6a58..0629e09f6511 100644
--- a/fs/ext3/namei.c
+++ b/fs/ext3/namei.c
@@ -922,7 +922,8 @@ restart:
                                 bh = ext3_getblk(NULL, dir, b++, 0, &err);
                                 bh_use[ra_max] = bh;
                                 if (bh)
-                                        ll_rw_block(READ_META, 1, &bh);
+                                        ll_rw_block(READ | REQ_META | REQ_PRIO,
+                                                    1, &bh);
                         }
                 }
                 if ((bh = bh_use[ra_ptr++]) == NULL)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 18d2558b7624..986e2388f031 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -647,7 +647,7 @@ struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
                 return bh;
         if (buffer_uptodate(bh))
                 return bh;
-        ll_rw_block(READ_META, 1, &bh);
+        ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
         wait_on_buffer(bh);
         if (buffer_uptodate(bh))
                 return bh;
@@ -3298,7 +3298,7 @@ make_io:
                 trace_ext4_load_inode(inode);
                 get_bh(bh);
                 bh->b_end_io = end_buffer_read_sync;
-                submit_bh(READ_META, bh);
+                submit_bh(READ | REQ_META | REQ_PRIO, bh);
                 wait_on_buffer(bh);
                 if (!buffer_uptodate(bh)) {
                         EXT4_ERROR_INODE_BLOCK(inode, block,
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index f8068c7bae9f..1c924faeb6c8 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -922,7 +922,8 @@ restart:
                                 bh = ext4_getblk(NULL, dir, b++, 0, &err);
                                 bh_use[ra_max] = bh;
                                 if (bh)
-                                        ll_rw_block(READ_META, 1, &bh);
+                                        ll_rw_block(READ | REQ_META | REQ_PRIO,
+                                                    1, &bh);
                         }
                 }
                 if ((bh = bh_use[ra_ptr++]) == NULL)
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 85c62923ee29..598646434362 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -624,9 +624,9 @@ static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)
         bh->b_end_io = end_buffer_write_sync;
         get_bh(bh);
         if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
-                submit_bh(WRITE_SYNC | REQ_META, bh);
+                submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh);
         else
-                submit_bh(WRITE_FLUSH_FUA | REQ_META, bh);
+                submit_bh(WRITE_FLUSH_FUA | REQ_META | REQ_PRIO, bh);
         wait_on_buffer(bh);
 
         if (!buffer_uptodate(bh))
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 747238cd9f96..be29858900f6 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -37,7 +37,7 @@ static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wb
 {
         struct buffer_head *bh, *head;
         int nr_underway = 0;
-        int write_op = REQ_META |
+        int write_op = REQ_META | REQ_PRIO |
                 (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
 
         BUG_ON(!PageLocked(page));
@@ -225,7 +225,7 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
         }
         bh->b_end_io = end_buffer_read_sync;
         get_bh(bh);
-        submit_bh(READ_SYNC | REQ_META, bh);
+        submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh);
         if (!(flags & DIO_WAIT))
                 return 0;
 
@@ -435,7 +435,7 @@ struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
         if (buffer_uptodate(first_bh))
                 goto out;
         if (!buffer_locked(first_bh))
-                ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh);
+                ll_rw_block(READ_SYNC | REQ_META | REQ_PRIO, 1, &first_bh);
 
         dblock++;
         extlen--;
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 3bc073a4cf82..079587e53849 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -224,7 +224,7 @@ static int gfs2_read_super(struct gfs2_sbd *sdp, sector_t sector, int silent)
 
         bio->bi_end_io = end_bio_io_page;
         bio->bi_private = page;
-        submit_bio(READ_SYNC | REQ_META, bio);
+        submit_bio(READ_SYNC | REQ_META | REQ_PRIO, bio);
         wait_on_page_locked(page);
         bio_put(bio);
         if (!PageUptodate(page)) {
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index 42e8d23bc047..0e8bb13381e4 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -709,7 +709,7 @@ get_a_page:
                 set_buffer_uptodate(bh);
 
         if (!buffer_uptodate(bh)) {
-                ll_rw_block(READ_META, 1, &bh);
+                ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
                 wait_on_buffer(bh);
                 if (!buffer_uptodate(bh))
                         goto unlock_out;
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 32f0076e844b..71fc53bb8f1c 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -124,6 +124,7 @@ enum rq_flag_bits {
 
         __REQ_SYNC,             /* request is sync (sync write or read) */
         __REQ_META,             /* metadata io request */
+        __REQ_PRIO,             /* boost priority in cfq */
         __REQ_DISCARD,          /* request to discard sectors */
         __REQ_SECURE,           /* secure discard (used with __REQ_DISCARD) */
 
@@ -161,14 +162,15 @@ enum rq_flag_bits {
 #define REQ_FAILFAST_DRIVER     (1 << __REQ_FAILFAST_DRIVER)
 #define REQ_SYNC                (1 << __REQ_SYNC)
 #define REQ_META                (1 << __REQ_META)
+#define REQ_PRIO                (1 << __REQ_PRIO)
 #define REQ_DISCARD             (1 << __REQ_DISCARD)
 #define REQ_NOIDLE              (1 << __REQ_NOIDLE)
 
 #define REQ_FAILFAST_MASK \
         (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
 #define REQ_COMMON_MASK \
-        (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_DISCARD | \
-         REQ_NOIDLE | REQ_FLUSH | REQ_FUA | REQ_SECURE)
+        (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
+         REQ_DISCARD | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | REQ_SECURE)
 #define REQ_CLONE_MASK          REQ_COMMON_MASK
 
 #define REQ_RAHEAD              (1 << __REQ_RAHEAD)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 84b15d54f8c2..7fbaa9103344 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -873,7 +873,6 @@ struct blk_plug {
         struct list_head list;
         struct list_head cb_list;
         unsigned int should_sort;
-        unsigned int count;
 };
 #define BLK_MAX_REQUEST_COUNT 16
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c2bd68f2277a..277f497923a2 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -162,10 +162,8 @@ struct inodes_stat_t {
 #define READA                   RWA_MASK
 
 #define READ_SYNC               (READ | REQ_SYNC)
-#define READ_META               (READ | REQ_META)
 #define WRITE_SYNC              (WRITE | REQ_SYNC | REQ_NOIDLE)
 #define WRITE_ODIRECT           (WRITE | REQ_SYNC)
-#define WRITE_META              (WRITE | REQ_META)
 #define WRITE_FLUSH             (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH)
 #define WRITE_FUA               (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FUA)
 #define WRITE_FLUSH_FUA         (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH | REQ_FUA)
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index d6edf8d14f9c..a87da524a4a0 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -359,6 +359,17 @@ static unsigned long bdi_longest_inactive(void)
         return max(5UL * 60 * HZ, interval);
 }
 
+/*
+ * Clear pending bit and wakeup anybody waiting for flusher thread creation or
+ * shutdown
+ */
+static void bdi_clear_pending(struct backing_dev_info *bdi)
+{
+        clear_bit(BDI_pending, &bdi->state);
+        smp_mb__after_clear_bit();
+        wake_up_bit(&bdi->state, BDI_pending);
+}
+
 static int bdi_forker_thread(void *ptr)
 {
         struct bdi_writeback *me = ptr;
@@ -390,6 +401,13 @@ static int bdi_forker_thread(void *ptr)
                 }
 
                 spin_lock_bh(&bdi_lock);
+                /*
+                 * In the following loop we are going to check whether we have
+                 * some work to do without any synchronization with tasks
+                 * waking us up to do work for them. So we have to set task
+                 * state already here so that we don't miss wakeups coming
+                 * after we verify some condition.
+                 */
                 set_current_state(TASK_INTERRUPTIBLE);
 
                 list_for_each_entry(bdi, &bdi_list, bdi_list) {
@@ -469,11 +487,13 @@ static int bdi_forker_thread(void *ptr)
                                 spin_unlock_bh(&bdi->wb_lock);
                                 wake_up_process(task);
                         }
+                        bdi_clear_pending(bdi);
                         break;
 
                 case KILL_THREAD:
                         __set_current_state(TASK_RUNNING);
                         kthread_stop(task);
+                        bdi_clear_pending(bdi);
                         break;
 
                 case NO_ACTION:
@@ -489,16 +509,8 @@ static int bdi_forker_thread(void *ptr)
                         else
                                 schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10));
                         try_to_freeze();
-                        /* Back to the main loop */
-                        continue;
+                        break;
                 }
-
-                /*
-                 * Clear pending bit and wakeup anybody waiting to tear us down.
-                 */
-                clear_bit(BDI_pending, &bdi->state);
-                smp_mb__after_clear_bit();
-                wake_up_bit(&bdi->state, BDI_pending);
         }
 
         return 0;