53 files changed, 1323 insertions, 1085 deletions

diff --git a/Documentation/cgroups/blkio-controller.txt b/Documentation/cgroups/blkio-controller.txt
index d6da611f8f63..4ed7b5ceeed2 100644
--- a/Documentation/cgroups/blkio-controller.txt
+++ b/Documentation/cgroups/blkio-controller.txt
@@ -89,6 +89,33 @@ Throttling/Upper Limit policy
 
  Limits for writes can be put using blkio.write_bps_device file.
 
+Hierarchical Cgroups
+====================
+- Currently none of the IO control policy supports hierarhical groups. But
+  cgroup interface does allow creation of hierarhical cgroups and internally
+  IO policies treat them as flat hierarchy.
+
+  So this patch will allow creation of cgroup hierarhcy but at the backend
+  everything will be treated as flat. So if somebody created a hierarchy like
+  as follows.
+
+                        root
+                        /  \
+                     test1 test2
+                        |
+                     test3
+
+  CFQ and throttling will practically treat all groups at same level.
+
+                                pivot
+                             /  |   \  \
+                        root  test1 test2  test3
+
+  Down the line we can implement hierarchical accounting/control support
+  and also introduce a new cgroup file "use_hierarchy" which will control
+  whether cgroup hierarchy is viewed as flat or hierarchical by the policy..
+  This is how memory controller also has implemented the things.
+
 Various user visible config options
 ===================================
 CONFIG_BLK_CGROUP
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index b1febd0f6d2a..455768a3eb9e 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1452,10 +1452,6 @@ blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
                 goto done;
         }
 
-        /* Currently we do not support hierarchy deeper than two level (0,1) */
-        if (parent != cgroup->top_cgroup)
-                return ERR_PTR(-EPERM);
-
         blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
         if (!blkcg)
                 return ERR_PTR(-ENOMEM);
diff --git a/block/blk-core.c b/block/blk-core.c
index 4ce953f1b390..2f4002f79a24 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -33,7 +33,7 @@
 
 #include "blk.h"
 
-EXPORT_TRACEPOINT_SYMBOL_GPL(block_remap);
+EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
 
@@ -64,13 +64,27 @@ static void drive_stat_acct(struct request *rq, int new_io)
                 return;
 
         cpu = part_stat_lock();
-        part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
 
-        if (!new_io)
+        if (!new_io) {
+                part = rq->part;
                 part_stat_inc(cpu, part, merges[rw]);
-        else {
+        } else {
+                part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
+                if (!hd_struct_try_get(part)) {
+                        /*
+                         * The partition is already being removed,
+                         * the request will be accounted on the disk only
+                         *
+                         * We take a reference on disk->part0 although that
+                         * partition will never be deleted, so we can treat
+                         * it as any other partition.
+                         */
+                        part = &rq->rq_disk->part0;
+                        hd_struct_get(part);
+                }
                 part_round_stats(cpu, part);
                 part_inc_in_flight(part, rw);
+                rq->part = part;
         }
 
         part_stat_unlock();
@@ -128,6 +142,7 @@ void blk_rq_init(struct request_queue *q, struct request *rq)
         rq->ref_count = 1;
         rq->start_time = jiffies;
         set_start_time_ns(rq);
+        rq->part = NULL;
 }
 EXPORT_SYMBOL(blk_rq_init);
 
@@ -1329,9 +1344,9 @@ static inline void blk_partition_remap(struct bio *bio)
                 bio->bi_sector += p->start_sect;
                 bio->bi_bdev = bdev->bd_contains;
 
-                trace_block_remap(bdev_get_queue(bio->bi_bdev), bio,
-                                    bdev->bd_dev,
-                                    bio->bi_sector - p->start_sect);
+                trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio,
+                                      bdev->bd_dev,
+                                      bio->bi_sector - p->start_sect);
         }
 }
 
@@ -1500,7 +1515,7 @@ static inline void __generic_make_request(struct bio *bio)
                         goto end_io;
 
                 if (old_sector != -1)
-                        trace_block_remap(q, bio, old_dev, old_sector);
+                        trace_block_bio_remap(q, bio, old_dev, old_sector);
 
                 old_sector = bio->bi_sector;
                 old_dev = bio->bi_bdev->bd_dev;
@@ -1776,7 +1791,7 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)
                 int cpu;
 
                 cpu = part_stat_lock();
-                part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+                part = req->part;
                 part_stat_add(cpu, part, sectors[rw], bytes >> 9);
                 part_stat_unlock();
         }
@@ -1796,13 +1811,14 @@ static void blk_account_io_done(struct request *req)
                 int cpu;
 
                 cpu = part_stat_lock();
-                part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+                part = req->part;
 
                 part_stat_inc(cpu, part, ios[rw]);
                 part_stat_add(cpu, part, ticks[rw], duration);
                 part_round_stats(cpu, part);
                 part_dec_in_flight(part, rw);
 
+                hd_struct_put(part);
                 part_stat_unlock();
         }
 }
@@ -2606,7 +2622,9 @@ int __init blk_dev_init(void)
         BUILD_BUG_ON(__REQ_NR_BITS > 8 *
                         sizeof(((struct request *)0)->cmd_flags));
 
-        kblockd_workqueue = create_workqueue("kblockd");
+        /* used for unplugging and affects IO latency/throughput - HIGHPRI */
+        kblockd_workqueue = alloc_workqueue("kblockd",
+                                            WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
         if (!kblockd_workqueue)
                 panic("Failed to create kblockd\n");
 
diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index 3c7a339fe381..b791022beef3 100644
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -64,7 +64,7 @@ static void cfq_exit(struct io_context *ioc)
         rcu_read_unlock();
 }
 
-/* Called by the exitting task */
+/* Called by the exiting task */
 void exit_io_context(struct task_struct *task)
 {
         struct io_context *ioc;
@@ -74,10 +74,9 @@ void exit_io_context(struct task_struct *task)
         task->io_context = NULL;
         task_unlock(task);
 
-        if (atomic_dec_and_test(&ioc->nr_tasks)) {
+        if (atomic_dec_and_test(&ioc->nr_tasks))
                 cfq_exit(ioc);
 
-        }
         put_io_context(ioc);
 }
 
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 74bc4a768f32..ea85e20d5e94 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -351,11 +351,12 @@ static void blk_account_io_merge(struct request *req)
                 int cpu;
 
                 cpu = part_stat_lock();
-                part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+                part = req->part;
 
                 part_round_stats(cpu, part);
                 part_dec_in_flight(part, rq_data_dir(req));
 
+                hd_struct_put(part);
                 part_stat_unlock();
         }
 }
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 78ee4b1d4e85..8427697c5437 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -87,7 +87,6 @@ struct cfq_rb_root {
         unsigned count;
         unsigned total_weight;
         u64 min_vdisktime;
-        struct rb_node *active;
 };
 #define CFQ_RB_ROOT     (struct cfq_rb_root) { .rb = RB_ROOT, .left = NULL, \
                         .count = 0, .min_vdisktime = 0, }
@@ -97,7 +96,7 @@ struct cfq_rb_root {
  */
 struct cfq_queue {
         /* reference count */
-        atomic_t ref;
+        int ref;
         /* various state flags, see below */
         unsigned int flags;
         /* parent cfq_data */
@@ -180,7 +179,6 @@ struct cfq_group {
         /* group service_tree key */
         u64 vdisktime;
         unsigned int weight;
-        bool on_st;
 
         /* number of cfqq currently on this group */
         int nr_cfqq;
@@ -209,7 +207,7 @@ struct cfq_group {
         struct blkio_group blkg;
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
         struct hlist_node cfqd_node;
-        atomic_t ref;
+        int ref;
 #endif
         /* number of requests that are on the dispatch list or inside driver */
         int dispatched;
@@ -563,11 +561,6 @@ static void update_min_vdisktime(struct cfq_rb_root *st)
         u64 vdisktime = st->min_vdisktime;
         struct cfq_group *cfqg;
 
-        if (st->active) {
-                cfqg = rb_entry_cfqg(st->active);
-                vdisktime = cfqg->vdisktime;
-        }
-
         if (st->left) {
                 cfqg = rb_entry_cfqg(st->left);
                 vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime);
@@ -646,11 +639,11 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 static inline bool cfq_slice_used(struct cfq_queue *cfqq)
 {
         if (cfq_cfqq_slice_new(cfqq))
-                return 0;
+                return false;
         if (time_before(jiffies, cfqq->slice_end))
-                return 0;
+                return false;
 
-        return 1;
+        return true;
 }
 
 /*
@@ -869,7 +862,7 @@ cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
         struct rb_node *n;
 
         cfqg->nr_cfqq++;
-        if (cfqg->on_st)
+        if (!RB_EMPTY_NODE(&cfqg->rb_node))
                 return;
 
         /*
@@ -885,7 +878,6 @@ cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
                 cfqg->vdisktime = st->min_vdisktime;
 
         __cfq_group_service_tree_add(st, cfqg);
-        cfqg->on_st = true;
         st->total_weight += cfqg->weight;
 }
 
@@ -894,9 +886,6 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
 {
         struct cfq_rb_root *st = &cfqd->grp_service_tree;
 
-        if (st->active == &cfqg->rb_node)
-                st->active = NULL;
-
         BUG_ON(cfqg->nr_cfqq < 1);
         cfqg->nr_cfqq--;
 
@@ -905,7 +894,6 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
                 return;
 
         cfq_log_cfqg(cfqd, cfqg, "del_from_rr group");
-        cfqg->on_st = false;
         st->total_weight -= cfqg->weight;
         if (!RB_EMPTY_NODE(&cfqg->rb_node))
                 cfq_rb_erase(&cfqg->rb_node, st);
@@ -1026,7 +1014,7 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
          * elevator which will be dropped by either elevator exit
          * or cgroup deletion path depending on who is exiting first.
          */
-        atomic_set(&cfqg->ref, 1);
+        cfqg->ref = 1;
 
         /*
          * Add group onto cgroup list. It might happen that bdi->dev is
@@ -1071,7 +1059,7 @@ static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create)
 
 static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg)
 {
-        atomic_inc(&cfqg->ref);
+        cfqg->ref++;
         return cfqg;
 }
 
@@ -1083,7 +1071,7 @@ static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg)
 
         cfqq->cfqg = cfqg;
         /* cfqq reference on cfqg */
-        atomic_inc(&cfqq->cfqg->ref);
+        cfqq->cfqg->ref++;
 }
 
 static void cfq_put_cfqg(struct cfq_group *cfqg)
@@ -1091,11 +1079,12 @@ static void cfq_put_cfqg(struct cfq_group *cfqg)
         struct cfq_rb_root *st;
         int i, j;
 
-        BUG_ON(atomic_read(&cfqg->ref) <= 0);
-        if (!atomic_dec_and_test(&cfqg->ref))
+        BUG_ON(cfqg->ref <= 0);
+        cfqg->ref--;
+        if (cfqg->ref)
                 return;
         for_each_cfqg_st(cfqg, i, j, st)
-                BUG_ON(!RB_EMPTY_ROOT(&st->rb) || st->active != NULL);
+                BUG_ON(!RB_EMPTY_ROOT(&st->rb));
         kfree(cfqg);
 }
 
@@ -1200,7 +1189,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                         cfq_group_service_tree_del(cfqd, cfqq->cfqg);
                 cfqq->orig_cfqg = cfqq->cfqg;
                 cfqq->cfqg = &cfqd->root_group;
-                atomic_inc(&cfqd->root_group.ref);
+                cfqd->root_group.ref++;
                 group_changed = 1;
         } else if (!cfqd->cfq_group_isolation
                    && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) {
@@ -1687,9 +1676,6 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
         if (cfqq == cfqd->active_queue)
                 cfqd->active_queue = NULL;
 
-        if (&cfqq->cfqg->rb_node == cfqd->grp_service_tree.active)
-                cfqd->grp_service_tree.active = NULL;
-
         if (cfqd->active_cic) {
                 put_io_context(cfqd->active_cic->ioc);
                 cfqd->active_cic = NULL;
@@ -1901,10 +1887,10 @@ static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq)
          * in their service tree.
          */
         if (service_tree->count == 1 && cfq_cfqq_sync(cfqq))
-                return 1;
+                return true;
         cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d",
                         service_tree->count);
-        return 0;
+        return false;
 }
 
 static void cfq_arm_slice_timer(struct cfq_data *cfqd)
@@ -2040,7 +2026,7 @@ static int cfqq_process_refs(struct cfq_queue *cfqq)
         int process_refs, io_refs;
 
         io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE];
-        process_refs = atomic_read(&cfqq->ref) - io_refs;
+        process_refs = cfqq->ref - io_refs;
         BUG_ON(process_refs < 0);
         return process_refs;
 }
@@ -2080,10 +2066,10 @@ static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
          */
         if (new_process_refs >= process_refs) {
                 cfqq->new_cfqq = new_cfqq;
-                atomic_add(process_refs, &new_cfqq->ref);
+                new_cfqq->ref += process_refs;
         } else {
                 new_cfqq->new_cfqq = cfqq;
-                atomic_add(new_process_refs, &cfqq->ref);
+                cfqq->ref += new_process_refs;
         }
 }
 
@@ -2116,12 +2102,7 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
         unsigned count;
         struct cfq_rb_root *st;
         unsigned group_slice;
-
-        if (!cfqg) {
-                cfqd->serving_prio = IDLE_WORKLOAD;
-                cfqd->workload_expires = jiffies + 1;
-                return;
-        }
+        enum wl_prio_t original_prio = cfqd->serving_prio;
 
         /* Choose next priority. RT > BE > IDLE */
         if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg))
@@ -2134,6 +2115,9 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
                 return;
         }
 
+        if (original_prio != cfqd->serving_prio)
+                goto new_workload;
+
         /*
          * For RT and BE, we have to choose also the type
          * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
@@ -2148,6 +2132,7 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
         if (count && !time_after(jiffies, cfqd->workload_expires))
                 return;
 
+new_workload:
         /* otherwise select new workload type */
         cfqd->serving_type =
                 cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio);
@@ -2199,7 +2184,6 @@ static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
         if (RB_EMPTY_ROOT(&st->rb))
                 return NULL;
         cfqg = cfq_rb_first_group(st);
-        st->active = &cfqg->rb_node;
         update_min_vdisktime(st);
         return cfqg;
 }
@@ -2293,6 +2277,17 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
                 goto keep_queue;
         }
 
+        /*
+         * This is a deep seek queue, but the device is much faster than
+         * the queue can deliver, don't idle
+         **/
+        if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) &&
+            (cfq_cfqq_slice_new(cfqq) ||
+            (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) {
+                cfq_clear_cfqq_deep(cfqq);
+                cfq_clear_cfqq_idle_window(cfqq);
+        }
+
         if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) {
                 cfqq = NULL;
                 goto keep_queue;
@@ -2367,12 +2362,12 @@ static inline bool cfq_slice_used_soon(struct cfq_data *cfqd,
 {
         /* the queue hasn't finished any request, can't estimate */
         if (cfq_cfqq_slice_new(cfqq))
-                return 1;
+                return true;
         if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched,
                 cfqq->slice_end))
-                return 1;
+                return true;
 
-        return 0;
+        return false;
 }
 
 static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
@@ -2538,9 +2533,10 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
         struct cfq_data *cfqd = cfqq->cfqd;
         struct cfq_group *cfqg, *orig_cfqg;
 
-        BUG_ON(atomic_read(&cfqq->ref) <= 0);
+        BUG_ON(cfqq->ref <= 0);
 
-        if (!atomic_dec_and_test(&cfqq->ref))
+        cfqq->ref--;
+        if (cfqq->ref)
                 return;
 
         cfq_log_cfqq(cfqd, cfqq, "put_queue");
@@ -2843,7 +2839,7 @@ static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
         RB_CLEAR_NODE(&cfqq->p_node);
         INIT_LIST_HEAD(&cfqq->fifo);
 
-        atomic_set(&cfqq->ref, 0);
+        cfqq->ref = 0;
         cfqq->cfqd = cfqd;
 
         cfq_mark_cfqq_prio_changed(cfqq);
@@ -2979,11 +2975,11 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc,
          * pin the queue now that it's allocated, scheduler exit will prune it
          */
         if (!is_sync && !(*async_cfqq)) {
-                atomic_inc(&cfqq->ref);
+                cfqq->ref++;
                 *async_cfqq = cfqq;
         }
 
-        atomic_inc(&cfqq->ref);
+        cfqq->ref++;
         return cfqq;
 }
 
@@ -3265,6 +3261,10 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
         if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
                 return true;
 
+        /* An idle queue should not be idle now for some reason */
+        if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq))
+                return true;
+
         if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
                 return false;
 
@@ -3681,13 +3681,13 @@ new_queue:
         }
 
         cfqq->allocated[rw]++;
-        atomic_inc(&cfqq->ref);
-
-        spin_unlock_irqrestore(q->queue_lock, flags);
-
+        cfqq->ref++;
         rq->elevator_private = cic;
         rq->elevator_private2 = cfqq;
         rq->elevator_private3 = cfq_ref_get_cfqg(cfqq->cfqg);
+
+        spin_unlock_irqrestore(q->queue_lock, flags);
+
         return 0;
 
 queue_fail:
@@ -3862,6 +3862,10 @@ static void *cfq_init_queue(struct request_queue *q)
         if (!cfqd)
                 return NULL;
 
+        /*
+         * Don't need take queue_lock in the routine, since we are
+         * initializing the ioscheduler, and nobody is using cfqd
+         */
         cfqd->cic_index = i;
 
         /* Init root service tree */
@@ -3881,7 +3885,7 @@ static void *cfq_init_queue(struct request_queue *q)
          * Take a reference to root group which we never drop. This is just
          * to make sure that cfq_put_cfqg() does not try to kfree root group
          */
-        atomic_set(&cfqg->ref, 1);
+        cfqg->ref = 1;
         rcu_read_lock();
         cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg,
                                         (void *)cfqd, 0);
@@ -3901,7 +3905,7 @@ static void *cfq_init_queue(struct request_queue *q)
          * will not attempt to free it.
          */
         cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0);
-        atomic_inc(&cfqd->oom_cfqq.ref);
+        cfqd->oom_cfqq.ref++;
         cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group);
 
         INIT_LIST_HEAD(&cfqd->cic_list);
diff --git a/block/genhd.c b/block/genhd.c
index 5fa2b44a72ff..6a5b772aa201 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -18,6 +18,7 @@
 #include <linux/buffer_head.h>
 #include <linux/mutex.h>
 #include <linux/idr.h>
+#include <linux/log2.h>
 
 #include "blk.h"
 
@@ -35,6 +36,10 @@ static DEFINE_IDR(ext_devt_idr);
 
 static struct device_type disk_type;
 
+static void disk_add_events(struct gendisk *disk);
+static void disk_del_events(struct gendisk *disk);
+static void disk_release_events(struct gendisk *disk);
+
 /**
  * disk_get_part - get partition
  * @disk: disk to look partition from
@@ -239,7 +244,7 @@ static struct blk_major_name {
 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
 
 /* index in the above - for now: assume no multimajor ranges */
-static inline int major_to_index(int major)
+static inline int major_to_index(unsigned major)
 {
         return major % BLKDEV_MAJOR_HASH_SIZE;
 }
@@ -502,6 +507,64 @@ static int exact_lock(dev_t devt, void *data)
         return 0;
 }
 
+void register_disk(struct gendisk *disk)
+{
+        struct device *ddev = disk_to_dev(disk);
+        struct block_device *bdev;
+        struct disk_part_iter piter;
+        struct hd_struct *part;
+        int err;
+
+        ddev->parent = disk->driverfs_dev;
+
+        dev_set_name(ddev, disk->disk_name);
+
+        /* delay uevents, until we scanned partition table */
+        dev_set_uevent_suppress(ddev, 1);
+
+        if (device_add(ddev))
+                return;
+        if (!sysfs_deprecated) {
+                err = sysfs_create_link(block_depr, &ddev->kobj,
+                                        kobject_name(&ddev->kobj));
+                if (err) {
+                        device_del(ddev);
+                        return;
+                }
+        }
+        disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
+        disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
+
+        /* No minors to use for partitions */
+        if (!disk_partitionable(disk))
+                goto exit;
+
+        /* No such device (e.g., media were just removed) */
+        if (!get_capacity(disk))
+                goto exit;
+
+        bdev = bdget_disk(disk, 0);
+        if (!bdev)
+                goto exit;
+
+        bdev->bd_invalidated = 1;
+        err = blkdev_get(bdev, FMODE_READ, NULL);
+        if (err < 0)
+                goto exit;
+        blkdev_put(bdev, FMODE_READ);
+
+exit:
+        /* announce disk after possible partitions are created */
+        dev_set_uevent_suppress(ddev, 0);
+        kobject_uevent(&ddev->kobj, KOBJ_ADD);
+
+        /* announce possible partitions */
+        disk_part_iter_init(&piter, disk, 0);
+        while ((part = disk_part_iter_next(&piter)))
+                kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
+        disk_part_iter_exit(&piter);
+}
+
 /**
  * add_disk - add partitioning information to kernel list
  * @disk: per-device partitioning information
@@ -551,18 +614,48 @@ void add_disk(struct gendisk *disk)
         retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
                                    "bdi");
         WARN_ON(retval);
-}
 
+        disk_add_events(disk);
+}
 EXPORT_SYMBOL(add_disk);
-EXPORT_SYMBOL(del_gendisk);     /* in partitions/check.c */
 
-void unlink_gendisk(struct gendisk *disk)
+void del_gendisk(struct gendisk *disk)
 {
+        struct disk_part_iter piter;
+        struct hd_struct *part;
+
+        disk_del_events(disk);
+
+        /* invalidate stuff */
+        disk_part_iter_init(&piter, disk,
+                             DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
+        while ((part = disk_part_iter_next(&piter))) {
+                invalidate_partition(disk, part->partno);
+                delete_partition(disk, part->partno);
+        }
+        disk_part_iter_exit(&piter);
+
+        invalidate_partition(disk, 0);
+        blk_free_devt(disk_to_dev(disk)->devt);
+        set_capacity(disk, 0);
+        disk->flags &= ~GENHD_FL_UP;
+
         sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
         bdi_unregister(&disk->queue->backing_dev_info);
         blk_unregister_queue(disk);
         blk_unregister_region(disk_devt(disk), disk->minors);
+
+        part_stat_set_all(&disk->part0, 0);
+        disk->part0.stamp = 0;
+
+        kobject_put(disk->part0.holder_dir);
+        kobject_put(disk->slave_dir);
+        disk->driverfs_dev = NULL;
+        if (!sysfs_deprecated)
+                sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
+        device_del(disk_to_dev(disk));
 }
+EXPORT_SYMBOL(del_gendisk);
 
 /**
  * get_gendisk - get partitioning information for a given device
@@ -735,7 +828,7 @@ static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
         static void *p;
 
         p = disk_seqf_start(seqf, pos);
-        if (!IS_ERR(p) && p && !*pos)
+        if (!IS_ERR_OR_NULL(p) && !*pos)
                 seq_puts(seqf, "major minor  #blocks  name\n\n");
         return p;
 }
@@ -1005,6 +1098,7 @@ static void disk_release(struct device *dev)
 {
         struct gendisk *disk = dev_to_disk(dev);
 
+        disk_release_events(disk);
         kfree(disk->random);
         disk_replace_part_tbl(disk, NULL);
         free_part_stats(&disk->part0);
@@ -1110,29 +1204,6 @@ static int __init proc_genhd_init(void)
 module_init(proc_genhd_init);
 #endif /* CONFIG_PROC_FS */
 
-static void media_change_notify_thread(struct work_struct *work)
-{
-        struct gendisk *gd = container_of(work, struct gendisk, async_notify);
-        char event[] = "MEDIA_CHANGE=1";
-        char *envp[] = { event, NULL };
-
-        /*
-         * set enviroment vars to indicate which event this is for
-         * so that user space will know to go check the media status.
-         */
-        kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
-        put_device(gd->driverfs_dev);
-}
-
-#if 0
-void genhd_media_change_notify(struct gendisk *disk)
-{
-        get_device(disk->driverfs_dev);
-        schedule_work(&disk->async_notify);
-}
-EXPORT_SYMBOL_GPL(genhd_media_change_notify);
-#endif  /*  0  */
-
 dev_t blk_lookup_devt(const char *name, int partno)
 {
         dev_t devt = MKDEV(0, 0);
@@ -1193,13 +1264,13 @@ struct gendisk *alloc_disk_node(int minors, int node_id)
                 }
                 disk->part_tbl->part[0] = &disk->part0;
 
+                hd_ref_init(&disk->part0);
+
                 disk->minors = minors;
                 rand_initialize_disk(disk);
                 disk_to_dev(disk)->class = &block_class;
                 disk_to_dev(disk)->type = &disk_type;
                 device_initialize(disk_to_dev(disk));
-                INIT_WORK(&disk->async_notify,
-                        media_change_notify_thread);
         }
         return disk;
 }
@@ -1291,3 +1362,422 @@ int invalidate_partition(struct gendisk *disk, int partno)
 }
 
 EXPORT_SYMBOL(invalidate_partition);
+
+/*
+ * Disk events - monitor disk events like media change and eject request.
+ */
+struct disk_events {
+        struct list_head        node;           /* all disk_event's */
+        struct gendisk          *disk;          /* the associated disk */
+        spinlock_t              lock;
+
+        int                     block;          /* event blocking depth */
+        unsigned int            pending;        /* events already sent out */
+        unsigned int            clearing;       /* events being cleared */
+
+        long                    poll_msecs;     /* interval, -1 for default */
+        struct delayed_work     dwork;
+};
+
+static const char *disk_events_strs[] = {
+        [ilog2(DISK_EVENT_MEDIA_CHANGE)]        = "media_change",
+        [ilog2(DISK_EVENT_EJECT_REQUEST)]       = "eject_request",
+};
+
+static char *disk_uevents[] = {
+        [ilog2(DISK_EVENT_MEDIA_CHANGE)]        = "DISK_MEDIA_CHANGE=1",
+        [ilog2(DISK_EVENT_EJECT_REQUEST)]       = "DISK_EJECT_REQUEST=1",
+};
+
+/* list of all disk_events */
+static DEFINE_MUTEX(disk_events_mutex);
+static LIST_HEAD(disk_events);
+
+/* disable in-kernel polling by default */
+static unsigned long disk_events_dfl_poll_msecs = 0;
+
+static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
+{
+        struct disk_events *ev = disk->ev;
+        long intv_msecs = 0;
+
+        /*
+         * If device-specific poll interval is set, always use it.  If
+         * the default is being used, poll iff there are events which
+         * can't be monitored asynchronously.
+         */
+        if (ev->poll_msecs >= 0)
+                intv_msecs = ev->poll_msecs;
+        else if (disk->events & ~disk->async_events)
+                intv_msecs = disk_events_dfl_poll_msecs;
+
+        return msecs_to_jiffies(intv_msecs);
+}
+
+static void __disk_block_events(struct gendisk *disk, bool sync)
+{
+        struct disk_events *ev = disk->ev;
+        unsigned long flags;
+        bool cancel;
+
+        spin_lock_irqsave(&ev->lock, flags);
+        cancel = !ev->block++;
+        spin_unlock_irqrestore(&ev->lock, flags);
+
+        if (cancel) {
+                if (sync)
+                        cancel_delayed_work_sync(&disk->ev->dwork);
+                else
+                        cancel_delayed_work(&disk->ev->dwork);
+        }
+}
+
+static void __disk_unblock_events(struct gendisk *disk, bool check_now)
+{
+        struct disk_events *ev = disk->ev;
+        unsigned long intv;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ev->lock, flags);
+
+        if (WARN_ON_ONCE(ev->block <= 0))
+                goto out_unlock;
+
+        if (--ev->block)
+                goto out_unlock;
+
+        /*
+         * Not exactly a latency critical operation, set poll timer
+         * slack to 25% and kick event check.
+         */
+        intv = disk_events_poll_jiffies(disk);
+        set_timer_slack(&ev->dwork.timer, intv / 4);
+        if (check_now)
+                queue_delayed_work(system_nrt_wq, &ev->dwork, 0);
+        else if (intv)
+                queue_delayed_work(system_nrt_wq, &ev->dwork, intv);
+out_unlock:
+        spin_unlock_irqrestore(&ev->lock, flags);
+}
+
+/**
+ * disk_block_events - block and flush disk event checking
+ * @disk: disk to block events for
+ *
+ * On return from this function, it is guaranteed that event checking
+ * isn't in progress and won't happen until unblocked by
+ * disk_unblock_events().  Events blocking is counted and the actual
+ * unblocking happens after the matching number of unblocks are done.
+ *
+ * Note that this intentionally does not block event checking from
+ * disk_clear_events().
+ *
+ * CONTEXT:
+ * Might sleep.
+ */
+void disk_block_events(struct gendisk *disk)
+{
+        if (disk->ev)
+                __disk_block_events(disk, true);
+}
+
+/**
+ * disk_unblock_events - unblock disk event checking
+ * @disk: disk to unblock events for
+ *
+ * Undo disk_block_events().  When the block count reaches zero, it
+ * starts events polling if configured.
+ *
+ * CONTEXT:
+ * Don't care.  Safe to call from irq context.
+ */
+void disk_unblock_events(struct gendisk *disk)
+{
+        if (disk->ev)
+                __disk_unblock_events(disk, true);
+}
+
+/**
+ * disk_check_events - schedule immediate event checking
+ * @disk: disk to check events for
+ *
+ * Schedule immediate event checking on @disk if not blocked.
+ *
+ * CONTEXT:
+ * Don't care.  Safe to call from irq context.
+ */
+void disk_check_events(struct gendisk *disk)
+{
+        if (disk->ev) {
+                __disk_block_events(disk, false);
+                __disk_unblock_events(disk, true);
+        }
+}
+EXPORT_SYMBOL_GPL(disk_check_events);
+
+/**
+ * disk_clear_events - synchronously check, clear and return pending events
+ * @disk: disk to fetch and clear events from
+ * @mask: mask of events to be fetched and clearted
+ *
+ * Disk events are synchronously checked and pending events in @mask
+ * are cleared and returned.  This ignores the block count.
+ *
+ * CONTEXT:
+ * Might sleep.
+ */
+unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
+{
+        const struct block_device_operations *bdops = disk->fops;
+        struct disk_events *ev = disk->ev;
+        unsigned int pending;
+
+        if (!ev) {
+                /* for drivers still using the old ->media_changed method */
+                if ((mask & DISK_EVENT_MEDIA_CHANGE) &&
+                    bdops->media_changed && bdops->media_changed(disk))
+                        return DISK_EVENT_MEDIA_CHANGE;
+                return 0;
+        }
+
+        /* tell the workfn about the events being cleared */
+        spin_lock_irq(&ev->lock);
+        ev->clearing |= mask;
+        spin_unlock_irq(&ev->lock);
+
+        /* uncondtionally schedule event check and wait for it to finish */
+        __disk_block_events(disk, true);
+        queue_delayed_work(system_nrt_wq, &ev->dwork, 0);
+        flush_delayed_work(&ev->dwork);
+        __disk_unblock_events(disk, false);
+
+        /* then, fetch and clear pending events */
+        spin_lock_irq(&ev->lock);
+        WARN_ON_ONCE(ev->clearing & mask);      /* cleared by workfn */
+        pending = ev->pending & mask;
+        ev->pending &= ~mask;
+        spin_unlock_irq(&ev->lock);
+
+        return pending;
+}
+
+static void disk_events_workfn(struct work_struct *work)
+{
+        struct delayed_work *dwork = to_delayed_work(work);
+        struct disk_events *ev = container_of(dwork, struct disk_events, dwork);
+        struct gendisk *disk = ev->disk;
+        char *envp[ARRAY_SIZE(disk_uevents) + 1] = { };
+        unsigned int clearing = ev->clearing;
+        unsigned int events;
+        unsigned long intv;
+        int nr_events = 0, i;
+
+        /* check events */
+        events = disk->fops->check_events(disk, clearing);
+
+        /* accumulate pending events and schedule next poll if necessary */
+        spin_lock_irq(&ev->lock);
+
+        events &= ~ev->pending;
+        ev->pending |= events;
+        ev->clearing &= ~clearing;
+
+        intv = disk_events_poll_jiffies(disk);
+        if (!ev->block && intv)
+                queue_delayed_work(system_nrt_wq, &ev->dwork, intv);
+
+        spin_unlock_irq(&ev->lock);
+
+        /* tell userland about new events */
+        for (i = 0; i < ARRAY_SIZE(disk_uevents); i++)
+                if (events & (1 << i))
+                        envp[nr_events++] = disk_uevents[i];
+
+        if (nr_events)
+                kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
+}
+
+/*
+ * A disk events enabled device has the following sysfs nodes under
+ * its /sys/block/X/ directory.
+ *
+ * events               : list of all supported events
+ * events_async         : list of events which can be detected w/o polling
+ * events_poll_msecs    : polling interval, 0: disable, -1: system default
+ */
+static ssize_t __disk_events_show(unsigned int events, char *buf)
+{
+        const char *delim = "";
+        ssize_t pos = 0;
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++)
+                if (events & (1 << i)) {
+                        pos += sprintf(buf + pos, "%s%s",
+                                       delim, disk_events_strs[i]);
+                        delim = " ";
+                }
+        if (pos)
+                pos += sprintf(buf + pos, "\n");
+        return pos;
+}
+
+static ssize_t disk_events_show(struct device *dev,
+                                struct device_attribute *attr, char *buf)
+{
+        struct gendisk *disk = dev_to_disk(dev);
+
+        return __disk_events_show(disk->events, buf);
+}
+
+static ssize_t disk_events_async_show(struct device *dev,
+                                      struct device_attribute *attr, char *buf)
+{
+        struct gendisk *disk = dev_to_disk(dev);
+
+        return __disk_events_show(disk->async_events, buf);
+}
+
+static ssize_t disk_events_poll_msecs_show(struct device *dev,
+                                           struct device_attribute *attr,
+                                           char *buf)
+{
+        struct gendisk *disk = dev_to_disk(dev);
+
+        return sprintf(buf, "%ld\n", disk->ev->poll_msecs);
+}
+
+static ssize_t disk_events_poll_msecs_store(struct device *dev,
+                                            struct device_attribute *attr,
+                                            const char *buf, size_t count)
+{
+        struct gendisk *disk = dev_to_disk(dev);
+        long intv;
+
+        if (!count || !sscanf(buf, "%ld", &intv))
+                return -EINVAL;
+
+        if (intv < 0 && intv != -1)
+                return -EINVAL;
+
+        __disk_block_events(disk, true);
+        disk->ev->poll_msecs = intv;
+        __disk_unblock_events(disk, true);
+
+        return count;
+}
+
+static const DEVICE_ATTR(events, S_IRUGO, disk_events_show, NULL);
+static const DEVICE_ATTR(events_async, S_IRUGO, disk_events_async_show, NULL);
+static const DEVICE_ATTR(events_poll_msecs, S_IRUGO|S_IWUSR,
+                         disk_events_poll_msecs_show,
+                         disk_events_poll_msecs_store);
+
+static const struct attribute *disk_events_attrs[] = {
+        &dev_attr_events.attr,
+        &dev_attr_events_async.attr,
+        &dev_attr_events_poll_msecs.attr,
+        NULL,
+};
+
+/*
+ * The default polling interval can be specified by the kernel
+ * parameter block.events_dfl_poll_msecs which defaults to 0
+ * (disable).  This can also be modified runtime by writing to
+ * /sys/module/block/events_dfl_poll_msecs.
+ */
+static int disk_events_set_dfl_poll_msecs(const char *val,
+                                          const struct kernel_param *kp)
+{
+        struct disk_events *ev;
+        int ret;
+
+        ret = param_set_ulong(val, kp);
+        if (ret < 0)
+                return ret;
+
+        mutex_lock(&disk_events_mutex);
+
+        list_for_each_entry(ev, &disk_events, node)
+                disk_check_events(ev->disk);
+
+        mutex_unlock(&disk_events_mutex);
+
+        return 0;
+}
+
+static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = {
+        .set    = disk_events_set_dfl_poll_msecs,
+        .get    = param_get_ulong,
+};
+
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX     "block."
+
+module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops,
+                &disk_events_dfl_poll_msecs, 0644);
+
+/*
+ * disk_{add|del|release}_events - initialize and destroy disk_events.
+ */
+static void disk_add_events(struct gendisk *disk)
+{
+        struct disk_events *ev;
+
+        if (!disk->fops->check_events || !(disk->events | disk->async_events))
+                return;
+
+        ev = kzalloc(sizeof(*ev), GFP_KERNEL);
+        if (!ev) {
+                pr_warn("%s: failed to initialize events\n", disk->disk_name);
+                return;
+        }
+
+        if (sysfs_create_files(&disk_to_dev(disk)->kobj,
+                               disk_events_attrs) < 0) {
+                pr_warn("%s: failed to create sysfs files for events\n",
+                        disk->disk_name);
+                kfree(ev);
+                return;
+        }
+
+        disk->ev = ev;
+
+        INIT_LIST_HEAD(&ev->node);
+        ev->disk = disk;
+        spin_lock_init(&ev->lock);
+        ev->block = 1;
+        ev->poll_msecs = -1;
+        INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);
+
+        mutex_lock(&disk_events_mutex);
+        list_add_tail(&ev->node, &disk_events);
+        mutex_unlock(&disk_events_mutex);
+
+        /*
+         * Block count is initialized to 1 and the following initial
+         * unblock kicks it into action.
+         */
+        __disk_unblock_events(disk, true);
+}
+
+static void disk_del_events(struct gendisk *disk)
+{
+        if (!disk->ev)
+                return;
+
+        __disk_block_events(disk, true);
+
+        mutex_lock(&disk_events_mutex);
+        list_del_init(&disk->ev->node);
+        mutex_unlock(&disk_events_mutex);
+
+        sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
+}
+
+static void disk_release_events(struct gendisk *disk)
+{
+        /* the block count should be 1 from disk_del_events() */
+        WARN_ON_ONCE(disk->ev && disk->ev->block != 1);
+        kfree(disk->ev);
+}
diff --git a/block/ioctl.c b/block/ioctl.c
index a9a302eba01e..9049d460fa89 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -294,11 +294,12 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
                         return -EINVAL;
                 if (get_user(n, (int __user *) arg))
                         return -EFAULT;
-                if (!(mode & FMODE_EXCL) && bd_claim(bdev, &bdev) < 0)
+                if (!(mode & FMODE_EXCL) &&
+                    blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
                         return -EBUSY;
                 ret = set_blocksize(bdev, n);
                 if (!(mode & FMODE_EXCL))
-                        bd_release(bdev);
+                        blkdev_put(bdev, mode | FMODE_EXCL);
                 return ret;
         case BLKPG:
                 ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 1ea1a34e78b2..3803a0348937 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -911,8 +911,6 @@ struct drbd_md {
 struct drbd_backing_dev {
         struct block_device *backing_bdev;
         struct block_device *md_bdev;
-        struct file *lo_file;
-        struct file *md_file;
         struct drbd_md md;
         struct disk_conf dc; /* The user provided config... */
         sector_t known_size; /* last known size of that backing device */
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 6be5401d0e88..29cd0dc9fe4f 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -3372,11 +3372,8 @@ void drbd_free_bc(struct drbd_backing_dev *ldev)
         if (ldev == NULL)
                 return;
 
-        bd_release(ldev->backing_bdev);
-        bd_release(ldev->md_bdev);
-
-        fput(ldev->lo_file);
-        fput(ldev->md_file);
+        blkdev_put(ldev->backing_bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+        blkdev_put(ldev->md_bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
 
         kfree(ldev);
 }
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 29e5c70e4e26..8cbfaa687d72 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -855,7 +855,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
         sector_t max_possible_sectors;
         sector_t min_md_device_sectors;
         struct drbd_backing_dev *nbc = NULL; /* new_backing_conf */
-        struct inode *inode, *inode2;
+        struct block_device *bdev;
         struct lru_cache *resync_lru = NULL;
         union drbd_state ns, os;
         unsigned int max_seg_s;
@@ -907,46 +907,40 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
                 }
         }
 
-        nbc->lo_file = filp_open(nbc->dc.backing_dev, O_RDWR, 0);
-        if (IS_ERR(nbc->lo_file)) {
+        bdev = blkdev_get_by_path(nbc->dc.backing_dev,
+                                  FMODE_READ | FMODE_WRITE | FMODE_EXCL, mdev);
+        if (IS_ERR(bdev)) {
                 dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.backing_dev,
-                    PTR_ERR(nbc->lo_file));
-                nbc->lo_file = NULL;
+                        PTR_ERR(bdev));
                 retcode = ERR_OPEN_DISK;
                 goto fail;
         }
+        nbc->backing_bdev = bdev;
 
-        inode = nbc->lo_file->f_dentry->d_inode;
-
-        if (!S_ISBLK(inode->i_mode)) {
-                retcode = ERR_DISK_NOT_BDEV;
-                goto fail;
-        }
-
-        nbc->md_file = filp_open(nbc->dc.meta_dev, O_RDWR, 0);
-        if (IS_ERR(nbc->md_file)) {
+        /*
+         * meta_dev_idx >= 0: external fixed size, possibly multiple
+         * drbd sharing one meta device.  TODO in that case, paranoia
+         * check that [md_bdev, meta_dev_idx] is not yet used by some
+         * other drbd minor!  (if you use drbd.conf + drbdadm, that
+         * should check it for you already; but if you don't, or
+         * someone fooled it, we need to double check here)
+         */
+        bdev = blkdev_get_by_path(nbc->dc.meta_dev,
+                                  FMODE_READ | FMODE_WRITE | FMODE_EXCL,
+                                  (nbc->dc.meta_dev_idx < 0) ?
+                                  (void *)mdev : (void *)drbd_m_holder);
+        if (IS_ERR(bdev)) {
                 dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.meta_dev,
-                    PTR_ERR(nbc->md_file));
-                nbc->md_file = NULL;
+                        PTR_ERR(bdev));
                 retcode = ERR_OPEN_MD_DISK;
                 goto fail;
         }
+        nbc->md_bdev = bdev;
 
-        inode2 = nbc->md_file->f_dentry->d_inode;
-
-        if (!S_ISBLK(inode2->i_mode)) {
-                retcode = ERR_MD_NOT_BDEV;
-                goto fail;
-        }
-
-        nbc->backing_bdev = inode->i_bdev;
-        if (bd_claim(nbc->backing_bdev, mdev)) {
-                printk(KERN_ERR "drbd: bd_claim(%p,%p); failed [%p;%p;%u]\n",
-                       nbc->backing_bdev, mdev,
-                       nbc->backing_bdev->bd_holder,
-                       nbc->backing_bdev->bd_contains->bd_holder,
-                       nbc->backing_bdev->bd_holders);
-                retcode = ERR_BDCLAIM_DISK;
+        if ((nbc->backing_bdev == nbc->md_bdev) !=
+            (nbc->dc.meta_dev_idx == DRBD_MD_INDEX_INTERNAL ||
+             nbc->dc.meta_dev_idx == DRBD_MD_INDEX_FLEX_INT)) {
+                retcode = ERR_MD_IDX_INVALID;
                 goto fail;
         }
 
@@ -955,28 +949,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
                         offsetof(struct bm_extent, lce));
         if (!resync_lru) {
                 retcode = ERR_NOMEM;
-                goto release_bdev_fail;
-        }
-
-        /* meta_dev_idx >= 0: external fixed size,
-         * possibly multiple drbd sharing one meta device.
-         * TODO in that case, paranoia check that [md_bdev, meta_dev_idx] is
-         * not yet used by some other drbd minor!
-         * (if you use drbd.conf + drbdadm,
-         * that should check it for you already; but if you don't, or someone
-         * fooled it, we need to double check here) */
-        nbc->md_bdev = inode2->i_bdev;
-        if (bd_claim(nbc->md_bdev, (nbc->dc.meta_dev_idx < 0) ? (void *)mdev
-                                : (void *) drbd_m_holder)) {
-                retcode = ERR_BDCLAIM_MD_DISK;
-                goto release_bdev_fail;
-        }
-
-        if ((nbc->backing_bdev == nbc->md_bdev) !=
-            (nbc->dc.meta_dev_idx == DRBD_MD_INDEX_INTERNAL ||
-             nbc->dc.meta_dev_idx == DRBD_MD_INDEX_FLEX_INT)) {
-                retcode = ERR_MD_IDX_INVALID;
-                goto release_bdev2_fail;
+                goto fail;
         }
 
         /* RT - for drbd_get_max_capacity() DRBD_MD_INDEX_FLEX_INT */
@@ -987,7 +960,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
                         (unsigned long long) drbd_get_max_capacity(nbc),
                         (unsigned long long) nbc->dc.disk_size);
                 retcode = ERR_DISK_TO_SMALL;
-                goto release_bdev2_fail;
+                goto fail;
         }
 
         if (nbc->dc.meta_dev_idx < 0) {
@@ -1004,7 +977,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
                 dev_warn(DEV, "refusing attach: md-device too small, "
                      "at least %llu sectors needed for this meta-disk type\n",
                      (unsigned long long) min_md_device_sectors);
-                goto release_bdev2_fail;
+                goto fail;
         }
 
         /* Make sure the new disk is big enough
@@ -1012,7 +985,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
         if (drbd_get_max_capacity(nbc) <
             drbd_get_capacity(mdev->this_bdev)) {
                 retcode = ERR_DISK_TO_SMALL;
-                goto release_bdev2_fail;
+                goto fail;
         }
 
         nbc->known_size = drbd_get_capacity(nbc->backing_bdev);
@@ -1035,7 +1008,7 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
         retcode = _drbd_request_state(mdev, NS(disk, D_ATTACHING), CS_VERBOSE);
         drbd_resume_io(mdev);
         if (retcode < SS_SUCCESS)
-                goto release_bdev2_fail;
+                goto fail;
 
         if (!get_ldev_if_state(mdev, D_ATTACHING))
                 goto force_diskless;
@@ -1269,18 +1242,14 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
  force_diskless:
         drbd_force_state(mdev, NS(disk, D_FAILED));
         drbd_md_sync(mdev);
- release_bdev2_fail:
-        if (nbc)
-                bd_release(nbc->md_bdev);
- release_bdev_fail:
-        if (nbc)
-                bd_release(nbc->backing_bdev);
  fail:
         if (nbc) {
-                if (nbc->lo_file)
-                        fput(nbc->lo_file);
-                if (nbc->md_file)
-                        fput(nbc->md_file);
+                if (nbc->backing_bdev)
+                        blkdev_put(nbc->backing_bdev,
+                                   FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+                if (nbc->md_bdev)
+                        blkdev_put(nbc->md_bdev,
+                                   FMODE_READ | FMODE_WRITE | FMODE_EXCL);
                 kfree(nbc);
         }
         lc_destroy(resync_lru);
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 7ea0bea2f7e3..44e18c073c44 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -395,11 +395,7 @@ lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
         struct loop_device *lo = p->lo;
         struct page *page = buf->page;
         sector_t IV;
-        int size, ret;
-
-        ret = buf->ops->confirm(pipe, buf);
-        if (unlikely(ret))
-                return ret;
+        int size;
 
         IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) +
                                                         (buf->offset >> 9);
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 19b3568e9326..77d70eebb6b2 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2296,15 +2296,12 @@ static int pkt_open_dev(struct pktcdvd_device *pd, fmode_t write)
          * so bdget() can't fail.
          */
         bdget(pd->bdev->bd_dev);
-        if ((ret = blkdev_get(pd->bdev, FMODE_READ)))
+        if ((ret = blkdev_get(pd->bdev, FMODE_READ | FMODE_EXCL, pd)))
                 goto out;
 
-        if ((ret = bd_claim(pd->bdev, pd)))
-                goto out_putdev;
-
         if ((ret = pkt_get_last_written(pd, &lba))) {
                 printk(DRIVER_NAME": pkt_get_last_written failed\n");
-                goto out_unclaim;
+                goto out_putdev;
         }
 
         set_capacity(pd->disk, lba << 2);
@@ -2314,7 +2311,7 @@ static int pkt_open_dev(struct pktcdvd_device *pd, fmode_t write)
         q = bdev_get_queue(pd->bdev);
         if (write) {
                 if ((ret = pkt_open_write(pd)))
-                        goto out_unclaim;
+                        goto out_putdev;
                 /*
                  * Some CDRW drives can not handle writes larger than one packet,
                  * even if the size is a multiple of the packet size.
@@ -2329,23 +2326,21 @@ static int pkt_open_dev(struct pktcdvd_device *pd, fmode_t write)
         }
 
         if ((ret = pkt_set_segment_merging(pd, q)))
-                goto out_unclaim;
+                goto out_putdev;
 
         if (write) {
                 if (!pkt_grow_pktlist(pd, CONFIG_CDROM_PKTCDVD_BUFFERS)) {
                         printk(DRIVER_NAME": not enough memory for buffers\n");
                         ret = -ENOMEM;
-                        goto out_unclaim;
+                        goto out_putdev;
                 }
                 printk(DRIVER_NAME": %lukB available on disc\n", lba << 1);
         }
 
         return 0;
 
-out_unclaim:
-        bd_release(pd->bdev);
 out_putdev:
-        blkdev_put(pd->bdev, FMODE_READ);
+        blkdev_put(pd->bdev, FMODE_READ | FMODE_EXCL);
 out:
         return ret;
 }
@@ -2362,8 +2357,7 @@ static void pkt_release_dev(struct pktcdvd_device *pd, int flush)
         pkt_lock_door(pd, 0);
 
         pkt_set_speed(pd, MAX_SPEED, MAX_SPEED);
-        bd_release(pd->bdev);
-        blkdev_put(pd->bdev, FMODE_READ);
+        blkdev_put(pd->bdev, FMODE_READ | FMODE_EXCL);
 
         pkt_shrink_pktlist(pd);
 }
@@ -2733,7 +2727,7 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
         bdev = bdget(dev);
         if (!bdev)
                 return -ENOMEM;
-        ret = blkdev_get(bdev, FMODE_READ | FMODE_NDELAY);
+        ret = blkdev_get(bdev, FMODE_READ | FMODE_NDELAY, NULL);
         if (ret)
                 return ret;
 
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index af13c62dc473..14033a36bcd0 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -1348,7 +1348,10 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
         if (!CDROM_CAN(CDC_SELECT_DISC))
                 return -EDRIVE_CANT_DO_THIS;
 
-        (void) cdi->ops->media_changed(cdi, slot);
+        if (cdi->ops->check_events)
+                cdi->ops->check_events(cdi, 0, slot);
+        else
+                cdi->ops->media_changed(cdi, slot);
 
         if (slot == CDSL_NONE) {
                 /* set media changed bits, on both queues */
@@ -1392,6 +1395,42 @@ static int cdrom_select_disc(struct cdrom_device_info *cdi, int slot)
         return slot;
 }
 
+/*
+ * As cdrom implements an extra ioctl consumer for media changed
+ * event, it needs to buffer ->check_events() output, such that event
+ * is not lost for both the usual VFS and ioctl paths.
+ * cdi->{vfs|ioctl}_events are used to buffer pending events for each
+ * path.
+ *
+ * XXX: Locking is non-existent.  cdi->ops->check_events() can be
+ * called in parallel and buffering fields are accessed without any
+ * exclusion.  The original media_changed code had the same problem.
+ * It might be better to simply deprecate CDROM_MEDIA_CHANGED ioctl
+ * and remove this cruft altogether.  It doesn't have much usefulness
+ * at this point.
+ */
+static void cdrom_update_events(struct cdrom_device_info *cdi,
+                                unsigned int clearing)
+{
+        unsigned int events;
+
+        events = cdi->ops->check_events(cdi, clearing, CDSL_CURRENT);
+        cdi->vfs_events |= events;
+        cdi->ioctl_events |= events;
+}
+
+unsigned int cdrom_check_events(struct cdrom_device_info *cdi,
+                                unsigned int clearing)
+{
+        unsigned int events;
+
+        cdrom_update_events(cdi, clearing);
+        events = cdi->vfs_events;
+        cdi->vfs_events = 0;
+        return events;
+}
+EXPORT_SYMBOL(cdrom_check_events);
+
 /* We want to make media_changed accessible to the user through an
  * ioctl. The main problem now is that we must double-buffer the
  * low-level implementation, to assure that the VFS and the user both
@@ -1403,15 +1442,26 @@ int media_changed(struct cdrom_device_info *cdi, int queue)
 {
         unsigned int mask = (1 << (queue & 1));
         int ret = !!(cdi->mc_flags & mask);
+        bool changed;
 
         if (!CDROM_CAN(CDC_MEDIA_CHANGED))
-            return ret;
+                return ret;
+
         /* changed since last call? */
-        if (cdi->ops->media_changed(cdi, CDSL_CURRENT)) {
+        if (cdi->ops->check_events) {
+                BUG_ON(!queue); /* shouldn't be called from VFS path */
+                cdrom_update_events(cdi, DISK_EVENT_MEDIA_CHANGE);
+                changed = cdi->ioctl_events & DISK_EVENT_MEDIA_CHANGE;
+                cdi->ioctl_events = 0;
+        } else
+                changed = cdi->ops->media_changed(cdi, CDSL_CURRENT);
+
+        if (changed) {
                 cdi->mc_flags = 0x3;    /* set bit on both queues */
                 ret |= 1;
                 cdi->media_written = 0;
         }
+
         cdi->mc_flags &= ~mask;         /* clear bit */
         return ret;
 }
diff --git a/drivers/char/raw.c b/drivers/char/raw.c
index bfe25ea9766b..b4b9d5a47885 100644
--- a/drivers/char/raw.c
+++ b/drivers/char/raw.c
@@ -65,15 +65,12 @@ static int raw_open(struct inode *inode, struct file *filp)
         if (!bdev)
                 goto out;
         igrab(bdev->bd_inode);
-        err = blkdev_get(bdev, filp->f_mode);
+        err = blkdev_get(bdev, filp->f_mode | FMODE_EXCL, raw_open);
         if (err)
                 goto out;
-        err = bd_claim(bdev, raw_open);
-        if (err)
-                goto out1;
         err = set_blocksize(bdev, bdev_logical_block_size(bdev));
         if (err)
-                goto out2;
+                goto out1;
         filp->f_flags |= O_DIRECT;
         filp->f_mapping = bdev->bd_inode->i_mapping;
         if (++raw_devices[minor].inuse == 1)
@@ -83,10 +80,8 @@ static int raw_open(struct inode *inode, struct file *filp)
         mutex_unlock(&raw_mutex);
         return 0;
 
-out2:
-        bd_release(bdev);
 out1:
-        blkdev_put(bdev, filp->f_mode);
+        blkdev_put(bdev, filp->f_mode | FMODE_EXCL);
 out:
         mutex_unlock(&raw_mutex);
         return err;
@@ -110,8 +105,7 @@ static int raw_release(struct inode *inode, struct file *filp)
         }
         mutex_unlock(&raw_mutex);
 
-        bd_release(bdev);
-        blkdev_put(bdev, filp->f_mode);
+        blkdev_put(bdev, filp->f_mode | FMODE_EXCL);
         return 0;
 }
 
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 4d705cea0f8c..985c20a4f30e 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -325,15 +325,18 @@ static int open_dev(struct dm_dev_internal *d, dev_t dev,
 
         BUG_ON(d->dm_dev.bdev);
 
-        bdev = open_by_devnum(dev, d->dm_dev.mode);
+        bdev = blkdev_get_by_dev(dev, d->dm_dev.mode | FMODE_EXCL, _claim_ptr);
         if (IS_ERR(bdev))
                 return PTR_ERR(bdev);
-        r = bd_claim_by_disk(bdev, _claim_ptr, dm_disk(md));
-        if (r)
-                blkdev_put(bdev, d->dm_dev.mode);
-        else
-                d->dm_dev.bdev = bdev;
-        return r;
+
+        r = bd_link_disk_holder(bdev, dm_disk(md));
+        if (r) {
+                blkdev_put(bdev, d->dm_dev.mode | FMODE_EXCL);
+                return r;
+        }
+
+        d->dm_dev.bdev = bdev;
+        return 0;
 }
 
 /*
@@ -344,8 +347,7 @@ static void close_dev(struct dm_dev_internal *d, struct mapped_device *md)
         if (!d->dm_dev.bdev)
                 return;
 
-        bd_release_from_disk(d->dm_dev.bdev, dm_disk(md));
-        blkdev_put(d->dm_dev.bdev, d->dm_dev.mode);
+        blkdev_put(d->dm_dev.bdev, d->dm_dev.mode | FMODE_EXCL);
         d->dm_dev.bdev = NULL;
 }
 
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 7cb1352f7e7a..f48a2f359ac4 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -630,7 +630,7 @@ static void dec_pending(struct dm_io *io, int error)
                         queue_io(md, bio);
                 } else {
                         /* done with normal IO or empty flush */
-                        trace_block_bio_complete(md->queue, bio);
+                        trace_block_bio_complete(md->queue, bio, io_error);
                         bio_endio(bio, io_error);
                 }
         }
@@ -990,8 +990,8 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
         if (r == DM_MAPIO_REMAPPED) {
                 /* the bio has been remapped so dispatch it */
 
-                trace_block_remap(bdev_get_queue(clone->bi_bdev), clone,
-                                    tio->io->bio->bi_bdev->bd_dev, sector);
+                trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone,
+                                      tio->io->bio->bi_bdev->bd_dev, sector);
 
                 generic_make_request(clone);
         } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 175c424f201f..7fc090ac9e28 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1879,7 +1879,7 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
         rdev->sysfs_state = sysfs_get_dirent_safe(rdev->kobj.sd, "state");
 
         list_add_rcu(&rdev->same_set, &mddev->disks);
-        bd_claim_by_disk(rdev->bdev, rdev->bdev->bd_holder, mddev->gendisk);
+        bd_link_disk_holder(rdev->bdev, mddev->gendisk);
 
         /* May as well allow recovery to be retried once */
         mddev->recovery_disabled = 0;
@@ -1906,7 +1906,6 @@ static void unbind_rdev_from_array(mdk_rdev_t * rdev)
                 MD_BUG();
                 return;
         }
-        bd_release_from_disk(rdev->bdev, rdev->mddev->gendisk);
         list_del_rcu(&rdev->same_set);
         printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
         rdev->mddev = NULL;
@@ -1934,19 +1933,13 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev, int shared)
         struct block_device *bdev;
         char b[BDEVNAME_SIZE];
 
-        bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
+        bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
+                                 shared ? (mdk_rdev_t *)lock_rdev : rdev);
         if (IS_ERR(bdev)) {
                 printk(KERN_ERR "md: could not open %s.\n",
                         __bdevname(dev, b));
                 return PTR_ERR(bdev);
         }
-        err = bd_claim(bdev, shared ? (mdk_rdev_t *)lock_rdev : rdev);
-        if (err) {
-                printk(KERN_ERR "md: could not bd_claim %s.\n",
-                        bdevname(bdev, b));
-                blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
-                return err;
-        }
         if (!shared)
                 set_bit(AllReserved, &rdev->flags);
         rdev->bdev = bdev;
@@ -1959,8 +1952,7 @@ static void unlock_rdev(mdk_rdev_t *rdev)
         rdev->bdev = NULL;
         if (!bdev)
                 MD_BUG();
-        bd_release(bdev);
-        blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
+        blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
 }
 
 void md_autodetect_dev(dev_t dev);
diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index 2cf0cc6a4189..f29a6f9df6e7 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -224,7 +224,7 @@ static void block2mtd_free_device(struct block2mtd_dev *dev)
         if (dev->blkdev) {
                 invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping,
                                         0, -1);
-                close_bdev_exclusive(dev->blkdev, FMODE_READ|FMODE_WRITE);
+                blkdev_put(dev->blkdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
         }
 
         kfree(dev);
@@ -234,6 +234,7 @@ static void block2mtd_free_device(struct block2mtd_dev *dev)
 /* FIXME: ensure that mtd->size % erase_size == 0 */
 static struct block2mtd_dev *add_device(char *devname, int erase_size)
 {
+        const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
         struct block_device *bdev;
         struct block2mtd_dev *dev;
         char *name;
@@ -246,7 +247,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size)
                 return NULL;
 
         /* Get a handle on the device */
-        bdev = open_bdev_exclusive(devname, FMODE_READ|FMODE_WRITE, NULL);
+        bdev = blkdev_get_by_path(devname, mode, dev);
 #ifndef MODULE
         if (IS_ERR(bdev)) {
 
@@ -254,9 +255,8 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size)
                    to resolve the device name by other means. */
 
                 dev_t devt = name_to_dev_t(devname);
-                if (devt) {
-                        bdev = open_by_devnum(devt, FMODE_WRITE | FMODE_READ);
-                }
+                if (devt)
+                        bdev = blkdev_get_by_dev(devt, mode, dev);
         }
 #endif
 
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 30a1ca3d08b7..5505bc07e1e7 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -103,7 +103,7 @@ int dasd_scan_partitions(struct dasd_block *block)
         struct block_device *bdev;
 
         bdev = bdget_disk(block->gdp, 0);
-        if (!bdev || blkdev_get(bdev, FMODE_READ) < 0)
+        if (!bdev || blkdev_get(bdev, FMODE_READ, NULL) < 0)
                 return -ENODEV;
         /*
          * See fs/partition/check.c:register_disk,rescan_partitions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 501f67bef719..9045c52abd25 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1977,8 +1977,7 @@ EXPORT_SYMBOL(scsi_mode_sense);
  *              in.
  *
  *      Returns zero if unsuccessful or an error if TUR failed.  For
- *      removable media, a return of NOT_READY or UNIT_ATTENTION is
- *      translated to success, with the ->changed flag updated.
+ *      removable media, UNIT_ATTENTION sets ->changed flag.
  **/
 int
 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
@@ -2005,16 +2004,6 @@ scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
         } while (scsi_sense_valid(sshdr) &&
                  sshdr->sense_key == UNIT_ATTENTION && --retries);
 
-        if (!sshdr)
-                /* could not allocate sense buffer, so can't process it */
-                return result;
-
-        if (sdev->removable && scsi_sense_valid(sshdr) &&
-            (sshdr->sense_key == UNIT_ATTENTION ||
-             sshdr->sense_key == NOT_READY)) {
-                sdev->changed = 1;
-                result = 0;
-        }
         if (!sshdr_external)
                 kfree(sshdr);
         return result;
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 365024b0c407..b65e65aa07eb 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1043,15 +1043,7 @@ static int sd_media_changed(struct gendisk *disk)
                                               sshdr);
         }
 
-        /*
-         * Unable to test, unit probably not ready.   This usually
-         * means there is no disc in the drive.  Mark as changed,
-         * and we will figure it out later once the drive is
-         * available again.
-         */
-        if (retval || (scsi_sense_valid(sshdr) &&
-                       /* 0x3a is medium not present */
-                       sshdr->asc == 0x3a)) {
+        if (retval) {
                 set_media_not_present(sdkp);
                 goto out;
         }
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index d7b383c96d5d..be6baf8ad704 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -104,14 +104,15 @@ static void sr_release(struct cdrom_device_info *);
 static void get_sectorsize(struct scsi_cd *);
 static void get_capabilities(struct scsi_cd *);
 
-static int sr_media_change(struct cdrom_device_info *, int);
+static unsigned int sr_check_events(struct cdrom_device_info *cdi,
+                                    unsigned int clearing, int slot);
 static int sr_packet(struct cdrom_device_info *, struct packet_command *);
 
 static struct cdrom_device_ops sr_dops = {
         .open                   = sr_open,
         .release                = sr_release,
         .drive_status           = sr_drive_status,
-        .media_changed          = sr_media_change,
+        .check_events           = sr_check_events,
         .tray_move              = sr_tray_move,
         .lock_door              = sr_lock_door,
         .select_speed           = sr_select_speed,
@@ -165,90 +166,96 @@ static void scsi_cd_put(struct scsi_cd *cd)
         mutex_unlock(&sr_ref_mutex);
 }
 
-/* identical to scsi_test_unit_ready except that it doesn't
- * eat the NOT_READY returns for removable media */
-int sr_test_unit_ready(struct scsi_device *sdev, struct scsi_sense_hdr *sshdr)
+static unsigned int sr_get_events(struct scsi_device *sdev)
 {
-        int retries = MAX_RETRIES;
-        int the_result;
-        u8 cmd[] = {TEST_UNIT_READY, 0, 0, 0, 0, 0 };
+        u8 buf[8];
+        u8 cmd[] = { GET_EVENT_STATUS_NOTIFICATION,
+                     1,                 /* polled */
+                     0, 0,              /* reserved */
+                     1 << 4,            /* notification class: media */
+                     0, 0,              /* reserved */
+                     0, sizeof(buf),    /* allocation length */
+                     0,                 /* control */
+        };
+        struct event_header *eh = (void *)buf;
+        struct media_event_desc *med = (void *)(buf + 4);
+        struct scsi_sense_hdr sshdr;
+        int result;
 
-        /* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
-         * conditions are gone, or a timeout happens
-         */
-        do {
-                the_result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL,
-                                              0, sshdr, SR_TIMEOUT,
-                                              retries--, NULL);
-                if (scsi_sense_valid(sshdr) &&
-                    sshdr->sense_key == UNIT_ATTENTION)
-                        sdev->changed = 1;
-
-        } while (retries > 0 &&
-                 (!scsi_status_is_good(the_result) ||
-                  (scsi_sense_valid(sshdr) &&
-                   sshdr->sense_key == UNIT_ATTENTION)));
-        return the_result;
+        result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buf, sizeof(buf),
+                                  &sshdr, SR_TIMEOUT, MAX_RETRIES, NULL);
+        if (scsi_sense_valid(&sshdr) && sshdr.sense_key == UNIT_ATTENTION)
+                return DISK_EVENT_MEDIA_CHANGE;
+
+        if (result || be16_to_cpu(eh->data_len) < sizeof(*med))
+                return 0;
+
+        if (eh->nea || eh->notification_class != 0x4)
+                return 0;
+
+        if (med->media_event_code == 1)
+                return DISK_EVENT_EJECT_REQUEST;
+        else if (med->media_event_code == 2)
+                return DISK_EVENT_MEDIA_CHANGE;
+        return 0;
 }
 
 /*
- * This function checks to see if the media has been changed in the
- * CDROM drive.  It is possible that we have already sensed a change,
- * or the drive may have sensed one and not yet reported it.  We must
- * be ready for either case. This function always reports the current
- * value of the changed bit.  If flag is 0, then the changed bit is reset.
- * This function could be done as an ioctl, but we would need to have
- * an inode for that to work, and we do not always have one.
+ * This function checks to see if the media has been changed or eject
+ * button has been pressed.  It is possible that we have already
+ * sensed a change, or the drive may have sensed one and not yet
+ * reported it.  The past events are accumulated in sdev->changed and
+ * returned together with the current state.
  */
-
-static int sr_media_change(struct cdrom_device_info *cdi, int slot)
+static unsigned int sr_check_events(struct cdrom_device_info *cdi,
+                                    unsigned int clearing, int slot)
 {
         struct scsi_cd *cd = cdi->handle;
-        int retval;
-        struct scsi_sense_hdr *sshdr;
+        bool last_present;
+        struct scsi_sense_hdr sshdr;
+        unsigned int events;
+        int ret;
 
-        if (CDSL_CURRENT != slot) {
-                /* no changer support */
-                return -EINVAL;
-        }
+        /* no changer support */
+        if (CDSL_CURRENT != slot)
+                return 0;
 
-        sshdr =  kzalloc(sizeof(*sshdr), GFP_KERNEL);
-        retval = sr_test_unit_ready(cd->device, sshdr);
-        if (retval || (scsi_sense_valid(sshdr) &&
-                       /* 0x3a is medium not present */
-                       sshdr->asc == 0x3a)) {
-                /* Media not present or unable to test, unit probably not
-                 * ready. This usually means there is no disc in the drive.
-                 * Mark as changed, and we will figure it out later once
-                 * the drive is available again.
-                 */
-                cd->device->changed = 1;
-                /* This will force a flush, if called from check_disk_change */
-                retval = 1;
-                goto out;
-        };
+        events = sr_get_events(cd->device);
+        /*
+         * GET_EVENT_STATUS_NOTIFICATION is enough unless MEDIA_CHANGE
+         * is being cleared.  Note that there are devices which hang
+         * if asked to execute TUR repeatedly.
+         */
+        if (!(clearing & DISK_EVENT_MEDIA_CHANGE))
+                goto skip_tur;
+
+        /* let's see whether the media is there with TUR */
+        last_present = cd->media_present;
+        ret = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
+
+        /*
+         * Media is considered to be present if TUR succeeds or fails with
+         * sense data indicating something other than media-not-present
+         * (ASC 0x3a).
+         */
+        cd->media_present = scsi_status_is_good(ret) ||
+                (scsi_sense_valid(&sshdr) && sshdr.asc != 0x3a);
 
-        retval = cd->device->changed;
-        cd->device->changed = 0;
-        /* If the disk changed, the capacity will now be different,
-         * so we force a re-read of this information */
-        if (retval) {
-                /* check multisession offset etc */
-                sr_cd_check(cdi);
-                get_sectorsize(cd);
+        if (last_present != cd->media_present)
+                events |= DISK_EVENT_MEDIA_CHANGE;
+skip_tur:
+        if (cd->device->changed) {
+                events |= DISK_EVENT_MEDIA_CHANGE;
+                cd->device->changed = 0;
         }
 
-out:
-        /* Notify userspace, that media has changed. */
-        if (retval != cd->previous_state)
+        /* for backward compatibility */
+        if (events & DISK_EVENT_MEDIA_CHANGE)
                 sdev_evt_send_simple(cd->device, SDEV_EVT_MEDIA_CHANGE,
                                      GFP_KERNEL);
-        cd->previous_state = retval;
-        kfree(sshdr);
-
-        return retval;
+        return events;
 }
- 
+
 /*
  * sr_done is the interrupt routine for the device driver.
  *
@@ -533,10 +540,25 @@ out:
         return ret;
 }
 
-static int sr_block_media_changed(struct gendisk *disk)
+static unsigned int sr_block_check_events(struct gendisk *disk,
+                                          unsigned int clearing)
 {
         struct scsi_cd *cd = scsi_cd(disk);
-        return cdrom_media_changed(&cd->cdi);
+        return cdrom_check_events(&cd->cdi, clearing);
+}
+
+static int sr_block_revalidate_disk(struct gendisk *disk)
+{
+        struct scsi_cd *cd = scsi_cd(disk);
+        struct scsi_sense_hdr sshdr;
+
+        /* if the unit is not ready, nothing more to do */
+        if (scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr))
+                return 0;
+
+        sr_cd_check(&cd->cdi);
+        get_sectorsize(cd);
+        return 0;
 }
 
 static const struct block_device_operations sr_bdops =
@@ -545,7 +567,8 @@ static const struct block_device_operations sr_bdops =
         .open           = sr_block_open,
         .release        = sr_block_release,
         .ioctl          = sr_block_ioctl,
-        .media_changed  = sr_block_media_changed,
+        .check_events   = sr_block_check_events,
+        .revalidate_disk = sr_block_revalidate_disk,
         /* 
          * No compat_ioctl for now because sr_block_ioctl never
          * seems to pass arbitary ioctls down to host drivers.
@@ -618,6 +641,7 @@ static int sr_probe(struct device *dev)
         sprintf(disk->disk_name, "sr%d", minor);
         disk->fops = &sr_bdops;
         disk->flags = GENHD_FL_CD;
+        disk->events = DISK_EVENT_MEDIA_CHANGE | DISK_EVENT_EJECT_REQUEST;
 
         blk_queue_rq_timeout(sdev->request_queue, SR_TIMEOUT);
 
@@ -627,7 +651,7 @@ static int sr_probe(struct device *dev)
         cd->disk = disk;
         cd->capacity = 0x1fffff;
         cd->device->changed = 1;        /* force recheck CD type */
-        cd->previous_state = 1;
+        cd->media_present = 1;
         cd->use = 1;
         cd->readcd_known = 0;
         cd->readcd_cdda = 0;
@@ -780,7 +804,7 @@ static void get_capabilities(struct scsi_cd *cd)
         }
 
         /* eat unit attentions */
-        sr_test_unit_ready(cd->device, &sshdr);
+        scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
 
         /* ask for mode page 0x2a */
         rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128,
diff --git a/drivers/scsi/sr.h b/drivers/scsi/sr.h
index 1e144dfdbd4b..e036f1dc83c8 100644
--- a/drivers/scsi/sr.h
+++ b/drivers/scsi/sr.h
@@ -40,7 +40,7 @@ typedef struct scsi_cd {
         unsigned xa_flag:1;     /* CD has XA sectors ? */
         unsigned readcd_known:1;        /* drive supports READ_CD (0xbe) */
         unsigned readcd_cdda:1; /* reading audio data using READ_CD */
-        unsigned previous_state:1;      /* media has changed */
+        unsigned media_present:1;       /* media is present */
         struct cdrom_device_info cdi;
         /* We hold gendisk and scsi_device references on probe and use
          * the refs on this kref to decide when to release them */
@@ -61,7 +61,6 @@ int sr_select_speed(struct cdrom_device_info *cdi, int speed);
 int sr_audio_ioctl(struct cdrom_device_info *, unsigned int, void *);
 
 int sr_is_xa(Scsi_CD *);
-int sr_test_unit_ready(struct scsi_device *sdev, struct scsi_sense_hdr *sshdr);
 
 /* sr_vendor.c */
 void sr_vendor_init(Scsi_CD *);
diff --git a/drivers/scsi/sr_ioctl.c b/drivers/scsi/sr_ioctl.c
index 3cd8ffbad577..8be30554119b 100644
--- a/drivers/scsi/sr_ioctl.c
+++ b/drivers/scsi/sr_ioctl.c
@@ -307,7 +307,7 @@ int sr_drive_status(struct cdrom_device_info *cdi, int slot)
                 /* we have no changer support */
                 return -EINVAL;
         }
-        if (0 == sr_test_unit_ready(cd->device, &sshdr))
+        if (!scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr))
                 return CDS_DISC_OK;
 
         /* SK/ASC/ASCQ of 2/4/1 means "unit is becoming ready" */
diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c
index 3b513bafaf2a..b015561fd602 100644
--- a/drivers/usb/gadget/storage_common.c
+++ b/drivers/usb/gadget/storage_common.c
@@ -543,7 +543,7 @@ static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
         ro = curlun->initially_ro;
         if (!ro) {
                 filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
-                if (-EROFS == PTR_ERR(filp))
+                if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES)
                         ro = 1;
         }
         if (ro)
@@ -558,10 +558,7 @@ static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
 
         if (filp->f_path.dentry)
                 inode = filp->f_path.dentry->d_inode;
-        if (inode && S_ISBLK(inode->i_mode)) {
-                if (bdev_read_only(inode->i_bdev))
-                        ro = 1;
-        } else if (!inode || !S_ISREG(inode->i_mode)) {
+        if (!inode || (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
                 LINFO(curlun, "invalid file type: %s\n", filename);
                 goto out;
         }
diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index 4d0ff5ee27b8..e49cce234c65 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -782,7 +782,12 @@ void __init bio_integrity_init(void)
 {
         unsigned int i;
 
-        kintegrityd_wq = create_workqueue("kintegrityd");
+        /*
+         * kintegrityd won't block much but may burn a lot of CPU cycles.
+         * Make it highpri CPU intensive wq with max concurrency of 1.
+         */
+        kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
+                                         WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
         if (!kintegrityd_wq)
                 panic("Failed to create kintegrityd\n");
 
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 88da70355aa3..fe3f59c14a02 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -432,9 +432,6 @@ static void init_once(void *foo)
         mutex_init(&bdev->bd_mutex);
         INIT_LIST_HEAD(&bdev->bd_inodes);
         INIT_LIST_HEAD(&bdev->bd_list);
-#ifdef CONFIG_SYSFS
-        INIT_LIST_HEAD(&bdev->bd_holder_list);
-#endif
         inode_init_once(&ei->vfs_inode);
         /* Initialize mutex for freeze. */
         mutex_init(&bdev->bd_fsfreeze_mutex);
@@ -669,7 +666,7 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
         else if (bdev->bd_contains == bdev)
                 return true;     /* is a whole device which isn't held */
 
-        else if (whole->bd_holder == bd_claim)
+        else if (whole->bd_holder == bd_may_claim)
                 return true;     /* is a partition of a device that is being partitioned */
         else if (whole->bd_holder != NULL)
                 return false;    /* is a partition of a held device */
@@ -781,439 +778,87 @@ static struct block_device *bd_start_claiming(struct block_device *bdev,
         }
 }
 
-/* releases bdev_lock */
-static void __bd_abort_claiming(struct block_device *whole, void *holder)
-{
-        BUG_ON(whole->bd_claiming != holder);
-        whole->bd_claiming = NULL;
-        wake_up_bit(&whole->bd_claiming, 0);
-
-        spin_unlock(&bdev_lock);
-        bdput(whole);
-}
-
-/**
- * bd_abort_claiming - abort claiming a block device
- * @whole: whole block device returned by bd_start_claiming()
- * @holder: holder trying to claim @bdev
- *
- * Abort a claiming block started by bd_start_claiming().  Note that
- * @whole is not the block device to be claimed but the whole device
- * returned by bd_start_claiming().
- *
- * CONTEXT:
- * Grabs and releases bdev_lock.
- */
-static void bd_abort_claiming(struct block_device *whole, void *holder)
-{
-        spin_lock(&bdev_lock);
-        __bd_abort_claiming(whole, holder);             /* releases bdev_lock */
-}
-
-/* increment holders when we have a legitimate claim. requires bdev_lock */
-static void __bd_claim(struct block_device *bdev, struct block_device *whole,
-                                        void *holder)
-{
-        /* note that for a whole device bd_holders
-         * will be incremented twice, and bd_holder will
-         * be set to bd_claim before being set to holder
-         */
-        whole->bd_holders++;
-        whole->bd_holder = bd_claim;
-        bdev->bd_holders++;
-        bdev->bd_holder = holder;
-}
-
-/**
- * bd_finish_claiming - finish claiming a block device
- * @bdev: block device of interest (passed to bd_start_claiming())
- * @whole: whole block device returned by bd_start_claiming()
- * @holder: holder trying to claim @bdev
- *
- * Finish a claiming block started by bd_start_claiming().
- *
- * CONTEXT:
- * Grabs and releases bdev_lock.
- */
-static void bd_finish_claiming(struct block_device *bdev,
-                                struct block_device *whole, void *holder)
-{
-        spin_lock(&bdev_lock);
-        BUG_ON(!bd_may_claim(bdev, whole, holder));
-        __bd_claim(bdev, whole, holder);
-        __bd_abort_claiming(whole, holder); /* not actually an abort */
-}
-
-/**
- * bd_claim - claim a block device
- * @bdev: block device to claim
- * @holder: holder trying to claim @bdev
- *
- * Try to claim @bdev which must have been opened successfully.
- *
- * CONTEXT:
- * Might sleep.
- *
- * RETURNS:
- * 0 if successful, -EBUSY if @bdev is already claimed.
- */
-int bd_claim(struct block_device *bdev, void *holder)
-{
-        struct block_device *whole = bdev->bd_contains;
-        int res;
-
-        might_sleep();
-
-        spin_lock(&bdev_lock);
-        res = bd_prepare_to_claim(bdev, whole, holder);
-        if (res == 0)
-                __bd_claim(bdev, whole, holder);
-        spin_unlock(&bdev_lock);
-
-        return res;
-}
-EXPORT_SYMBOL(bd_claim);
-
-void bd_release(struct block_device *bdev)
-{
-        spin_lock(&bdev_lock);
-        if (!--bdev->bd_contains->bd_holders)
-                bdev->bd_contains->bd_holder = NULL;
-        if (!--bdev->bd_holders)
-                bdev->bd_holder = NULL;
-        spin_unlock(&bdev_lock);
-}
-
-EXPORT_SYMBOL(bd_release);
-
 #ifdef CONFIG_SYSFS
-/*
- * Functions for bd_claim_by_kobject / bd_release_from_kobject
- *
- *     If a kobject is passed to bd_claim_by_kobject()
- *     and the kobject has a parent directory,
- *     following symlinks are created:
- *        o from the kobject to the claimed bdev
- *        o from "holders" directory of the bdev to the parent of the kobject
- *     bd_release_from_kobject() removes these symlinks.
- *
- *     Example:
- *        If /dev/dm-0 maps to /dev/sda, kobject corresponding to
- *        /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
- *           /sys/block/dm-0/slaves/sda --> /sys/block/sda
- *           /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
- */
-
 static int add_symlink(struct kobject *from, struct kobject *to)
 {
-        if (!from || !to)
-                return 0;
         return sysfs_create_link(from, to, kobject_name(to));
 }
 
 static void del_symlink(struct kobject *from, struct kobject *to)
 {
-        if (!from || !to)
-                return;
         sysfs_remove_link(from, kobject_name(to));
 }
 
-/*
- * 'struct bd_holder' contains pointers to kobjects symlinked by
- * bd_claim_by_kobject.
- * It's connected to bd_holder_list which is protected by bdev->bd_sem.
- */
-struct bd_holder {
-        struct list_head list;  /* chain of holders of the bdev */
-        int count;              /* references from the holder */
-        struct kobject *sdir;   /* holder object, e.g. "/block/dm-0/slaves" */
-        struct kobject *hdev;   /* e.g. "/block/dm-0" */
-        struct kobject *hdir;   /* e.g. "/block/sda/holders" */
-        struct kobject *sdev;   /* e.g. "/block/sda" */
-};
-
-/*
- * Get references of related kobjects at once.
- * Returns 1 on success. 0 on failure.
- *
- * Should call bd_holder_release_dirs() after successful use.
- */
-static int bd_holder_grab_dirs(struct block_device *bdev,
-                        struct bd_holder *bo)
-{
-        if (!bdev || !bo)
-                return 0;
-
-        bo->sdir = kobject_get(bo->sdir);
-        if (!bo->sdir)
-                return 0;
-
-        bo->hdev = kobject_get(bo->sdir->parent);
-        if (!bo->hdev)
-                goto fail_put_sdir;
-
-        bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj);
-        if (!bo->sdev)
-                goto fail_put_hdev;
-
-        bo->hdir = kobject_get(bdev->bd_part->holder_dir);
-        if (!bo->hdir)
-                goto fail_put_sdev;
-
-        return 1;
-
-fail_put_sdev:
-        kobject_put(bo->sdev);
-fail_put_hdev:
-        kobject_put(bo->hdev);
-fail_put_sdir:
-        kobject_put(bo->sdir);
-
-        return 0;
-}
-
-/* Put references of related kobjects at once. */
-static void bd_holder_release_dirs(struct bd_holder *bo)
-{
-        kobject_put(bo->hdir);
-        kobject_put(bo->sdev);
-        kobject_put(bo->hdev);
-        kobject_put(bo->sdir);
-}
-
-static struct bd_holder *alloc_bd_holder(struct kobject *kobj)
-{
-        struct bd_holder *bo;
-
-        bo = kzalloc(sizeof(*bo), GFP_KERNEL);
-        if (!bo)
-                return NULL;
-
-        bo->count = 1;
-        bo->sdir = kobj;
-
-        return bo;
-}
-
-static void free_bd_holder(struct bd_holder *bo)
-{
-        kfree(bo);
-}
-
 /**
- * find_bd_holder - find matching struct bd_holder from the block device
+ * bd_link_disk_holder - create symlinks between holding disk and slave bdev
+ * @bdev: the claimed slave bdev
+ * @disk: the holding disk
  *
- * @bdev:       struct block device to be searched
- * @bo:         target struct bd_holder
- *
- * Returns matching entry with @bo in @bdev->bd_holder_list.
- * If found, increment the reference count and return the pointer.
- * If not found, returns NULL.
- */
-static struct bd_holder *find_bd_holder(struct block_device *bdev,
-                                        struct bd_holder *bo)
-{
-        struct bd_holder *tmp;
-
-        list_for_each_entry(tmp, &bdev->bd_holder_list, list)
-                if (tmp->sdir == bo->sdir) {
-                        tmp->count++;
-                        return tmp;
-                }
-
-        return NULL;
-}
-
-/**
- * add_bd_holder - create sysfs symlinks for bd_claim() relationship
- *
- * @bdev:       block device to be bd_claimed
- * @bo:         preallocated and initialized by alloc_bd_holder()
- *
- * Add @bo to @bdev->bd_holder_list, create symlinks.
- *
- * Returns 0 if symlinks are created.
- * Returns -ve if something fails.
- */
-static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
-{
-        int err;
-
-        if (!bo)
-                return -EINVAL;
-
-        if (!bd_holder_grab_dirs(bdev, bo))
-                return -EBUSY;
-
-        err = add_symlink(bo->sdir, bo->sdev);
-        if (err)
-                return err;
-
-        err = add_symlink(bo->hdir, bo->hdev);
-        if (err) {
-                del_symlink(bo->sdir, bo->sdev);
-                return err;
-        }
-
-        list_add_tail(&bo->list, &bdev->bd_holder_list);
-        return 0;
-}
-
-/**
- * del_bd_holder - delete sysfs symlinks for bd_claim() relationship
+ * This functions creates the following sysfs symlinks.
  *
- * @bdev:       block device to be bd_claimed
- * @kobj:       holder's kobject
+ * - from "slaves" directory of the holder @disk to the claimed @bdev
+ * - from "holders" directory of the @bdev to the holder @disk
  *
- * If there is matching entry with @kobj in @bdev->bd_holder_list
- * and no other bd_claim() from the same kobject,
- * remove the struct bd_holder from the list, delete symlinks for it.
+ * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
+ * passed to bd_link_disk_holder(), then:
  *
- * Returns a pointer to the struct bd_holder when it's removed from the list
- * and ready to be freed.
- * Returns NULL if matching claim isn't found or there is other bd_claim()
- * by the same kobject.
- */
-static struct bd_holder *del_bd_holder(struct block_device *bdev,
-                                        struct kobject *kobj)
-{
-        struct bd_holder *bo;
-
-        list_for_each_entry(bo, &bdev->bd_holder_list, list) {
-                if (bo->sdir == kobj) {
-                        bo->count--;
-                        BUG_ON(bo->count < 0);
-                        if (!bo->count) {
-                                list_del(&bo->list);
-                                del_symlink(bo->sdir, bo->sdev);
-                                del_symlink(bo->hdir, bo->hdev);
-                                bd_holder_release_dirs(bo);
-                                return bo;
-                        }
-                        break;
-                }
-        }
-
-        return NULL;
-}
-
-/**
- * bd_claim_by_kobject - bd_claim() with additional kobject signature
+ *   /sys/block/dm-0/slaves/sda --> /sys/block/sda
+ *   /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
  *
- * @bdev:       block device to be claimed
- * @holder:     holder's signature
- * @kobj:       holder's kobject
+ * The caller must have claimed @bdev before calling this function and
+ * ensure that both @bdev and @disk are valid during the creation and
+ * lifetime of these symlinks.
  *
- * Do bd_claim() and if it succeeds, create sysfs symlinks between
- * the bdev and the holder's kobject.
- * Use bd_release_from_kobject() when relesing the claimed bdev.
+ * CONTEXT:
+ * Might sleep.
  *
- * Returns 0 on success. (same as bd_claim())
- * Returns errno on failure.
+ * RETURNS:
+ * 0 on success, -errno on failure.
  */
-static int bd_claim_by_kobject(struct block_device *bdev, void *holder,
-                                struct kobject *kobj)
+int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 {
-        int err;
-        struct bd_holder *bo, *found;
-
-        if (!kobj)
-                return -EINVAL;
-
-        bo = alloc_bd_holder(kobj);
-        if (!bo)
-                return -ENOMEM;
+        int ret = 0;
 
         mutex_lock(&bdev->bd_mutex);
 
-        err = bd_claim(bdev, holder);
-        if (err)
-                goto fail;
+        WARN_ON_ONCE(!bdev->bd_holder || bdev->bd_holder_disk);
 
-        found = find_bd_holder(bdev, bo);
-        if (found)
-                goto fail;
+        /* FIXME: remove the following once add_disk() handles errors */
+        if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir))
+                goto out_unlock;
 
-        err = add_bd_holder(bdev, bo);
-        if (err)
-                bd_release(bdev);
-        else
-                bo = NULL;
-fail:
-        mutex_unlock(&bdev->bd_mutex);
-        free_bd_holder(bo);
-        return err;
-}
+        ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+        if (ret)
+                goto out_unlock;
 
-/**
- * bd_release_from_kobject - bd_release() with additional kobject signature
- *
- * @bdev:       block device to be released
- * @kobj:       holder's kobject
- *
- * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
- */
-static void bd_release_from_kobject(struct block_device *bdev,
-                                        struct kobject *kobj)
-{
-        if (!kobj)
-                return;
+        ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
+        if (ret) {
+                del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+                goto out_unlock;
+        }
 
-        mutex_lock(&bdev->bd_mutex);
-        bd_release(bdev);
-        free_bd_holder(del_bd_holder(bdev, kobj));
+        bdev->bd_holder_disk = disk;
+out_unlock:
         mutex_unlock(&bdev->bd_mutex);
+        return ret;
 }
+EXPORT_SYMBOL_GPL(bd_link_disk_holder);
 
-/**
- * bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
- *
- * @bdev:       block device to be claimed
- * @holder:     holder's signature
- * @disk:       holder's gendisk
- *
- * Call bd_claim_by_kobject() with getting @disk->slave_dir.
- */
-int bd_claim_by_disk(struct block_device *bdev, void *holder,
-                        struct gendisk *disk)
+static void bd_unlink_disk_holder(struct block_device *bdev)
 {
-        return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir));
-}
-EXPORT_SYMBOL_GPL(bd_claim_by_disk);
+        struct gendisk *disk = bdev->bd_holder_disk;
 
-/**
- * bd_release_from_disk - wrapper function for bd_release_from_kobject()
- *
- * @bdev:       block device to be claimed
- * @disk:       holder's gendisk
- *
- * Call bd_release_from_kobject() and put @disk->slave_dir.
- */
-void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk)
-{
-        bd_release_from_kobject(bdev, disk->slave_dir);
-        kobject_put(disk->slave_dir);
-}
-EXPORT_SYMBOL_GPL(bd_release_from_disk);
-#endif
+        bdev->bd_holder_disk = NULL;
+        if (!disk)
+                return;
 
-/*
- * Tries to open block device by device number.  Use it ONLY if you
- * really do not have anything better - i.e. when you are behind a
- * truly sucky interface and all you are given is a device number.  _Never_
- * to be used for internal purposes.  If you ever need it - reconsider
- * your API.
- */
-struct block_device *open_by_devnum(dev_t dev, fmode_t mode)
-{
-        struct block_device *bdev = bdget(dev);
-        int err = -ENOMEM;
-        if (bdev)
-                err = blkdev_get(bdev, mode);
-        return err ? ERR_PTR(err) : bdev;
+        del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+        del_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
 }
-
-EXPORT_SYMBOL(open_by_devnum);
+#else
+static inline void bd_unlink_disk_holder(struct block_device *bdev)
+{ }
+#endif
 
 /**
  * flush_disk - invalidates all buffer-cache entries on a disk
@@ -1309,10 +954,11 @@ int check_disk_change(struct block_device *bdev)
 {
         struct gendisk *disk = bdev->bd_disk;
         const struct block_device_operations *bdops = disk->fops;
+        unsigned int events;
 
-        if (!bdops->media_changed)
-                return 0;
-        if (!bdops->media_changed(bdev->bd_disk))
+        events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE |
+                                   DISK_EVENT_EJECT_REQUEST);
+        if (!(events & DISK_EVENT_MEDIA_CHANGE))
                 return 0;
 
         flush_disk(bdev);
@@ -1475,17 +1121,171 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
         return ret;
 }
 
-int blkdev_get(struct block_device *bdev, fmode_t mode)
+/**
+ * blkdev_get - open a block device
+ * @bdev: block_device to open
+ * @mode: FMODE_* mask
+ * @holder: exclusive holder identifier
+ *
+ * Open @bdev with @mode.  If @mode includes %FMODE_EXCL, @bdev is
+ * open with exclusive access.  Specifying %FMODE_EXCL with %NULL
+ * @holder is invalid.  Exclusive opens may nest for the same @holder.
+ *
+ * On success, the reference count of @bdev is unchanged.  On failure,
+ * @bdev is put.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
 {
-        return __blkdev_get(bdev, mode, 0);
+        struct block_device *whole = NULL;
+        int res;
+
+        WARN_ON_ONCE((mode & FMODE_EXCL) && !holder);
+
+        if ((mode & FMODE_EXCL) && holder) {
+                whole = bd_start_claiming(bdev, holder);
+                if (IS_ERR(whole)) {
+                        bdput(bdev);
+                        return PTR_ERR(whole);
+                }
+        }
+
+        res = __blkdev_get(bdev, mode, 0);
+
+        /* __blkdev_get() may alter read only status, check it afterwards */
+        if (!res && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
+                __blkdev_put(bdev, mode, 0);
+                res = -EACCES;
+        }
+
+        if (whole) {
+                /* finish claiming */
+                mutex_lock(&bdev->bd_mutex);
+                spin_lock(&bdev_lock);
+
+                if (!res) {
+                        BUG_ON(!bd_may_claim(bdev, whole, holder));
+                        /*
+                         * Note that for a whole device bd_holders
+                         * will be incremented twice, and bd_holder
+                         * will be set to bd_may_claim before being
+                         * set to holder
+                         */
+                        whole->bd_holders++;
+                        whole->bd_holder = bd_may_claim;
+                        bdev->bd_holders++;
+                        bdev->bd_holder = holder;
+                }
+
+                /* tell others that we're done */
+                BUG_ON(whole->bd_claiming != holder);
+                whole->bd_claiming = NULL;
+                wake_up_bit(&whole->bd_claiming, 0);
+
+                spin_unlock(&bdev_lock);
+
+                /*
+                 * Block event polling for write claims.  Any write
+                 * holder makes the write_holder state stick until all
+                 * are released.  This is good enough and tracking
+                 * individual writeable reference is too fragile given
+                 * the way @mode is used in blkdev_get/put().
+                 */
+                if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder) {
+                        bdev->bd_write_holder = true;
+                        disk_block_events(bdev->bd_disk);
+                }
+
+                mutex_unlock(&bdev->bd_mutex);
+                bdput(whole);
+        }
+
+        return res;
 }
 EXPORT_SYMBOL(blkdev_get);
 
+/**
+ * blkdev_get_by_path - open a block device by name
+ * @path: path to the block device to open
+ * @mode: FMODE_* mask
+ * @holder: exclusive holder identifier
+ *
+ * Open the blockdevice described by the device file at @path.  @mode
+ * and @holder are identical to blkdev_get().
+ *
+ * On success, the returned block_device has reference count of one.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * Pointer to block_device on success, ERR_PTR(-errno) on failure.
+ */
+struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
+                                        void *holder)
+{
+        struct block_device *bdev;
+        int err;
+
+        bdev = lookup_bdev(path);
+        if (IS_ERR(bdev))
+                return bdev;
+
+        err = blkdev_get(bdev, mode, holder);
+        if (err)
+                return ERR_PTR(err);
+
+        return bdev;
+}
+EXPORT_SYMBOL(blkdev_get_by_path);
+
+/**
+ * blkdev_get_by_dev - open a block device by device number
+ * @dev: device number of block device to open
+ * @mode: FMODE_* mask
+ * @holder: exclusive holder identifier
+ *
+ * Open the blockdevice described by device number @dev.  @mode and
+ * @holder are identical to blkdev_get().
+ *
+ * Use it ONLY if you really do not have anything better - i.e. when
+ * you are behind a truly sucky interface and all you are given is a
+ * device number.  _Never_ to be used for internal purposes.  If you
+ * ever need it - reconsider your API.
+ *
+ * On success, the returned block_device has reference count of one.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * Pointer to block_device on success, ERR_PTR(-errno) on failure.
+ */
+struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
+{
+        struct block_device *bdev;
+        int err;
+
+        bdev = bdget(dev);
+        if (!bdev)
+                return ERR_PTR(-ENOMEM);
+
+        err = blkdev_get(bdev, mode, holder);
+        if (err)
+                return ERR_PTR(err);
+
+        return bdev;
+}
+EXPORT_SYMBOL(blkdev_get_by_dev);
+
 static int blkdev_open(struct inode * inode, struct file * filp)
 {
-        struct block_device *whole = NULL;
         struct block_device *bdev;
-        int res;
 
         /*
          * Preserve backwards compatibility and allow large file access
@@ -1506,26 +1306,9 @@ static int blkdev_open(struct inode * inode, struct file * filp)
         if (bdev == NULL)
                 return -ENOMEM;
 
-        if (filp->f_mode & FMODE_EXCL) {
-                whole = bd_start_claiming(bdev, filp);
-                if (IS_ERR(whole)) {
-                        bdput(bdev);
-                        return PTR_ERR(whole);
-                }
-        }
-
         filp->f_mapping = bdev->bd_inode->i_mapping;
 
-        res = blkdev_get(bdev, filp->f_mode);
-
-        if (whole) {
-                if (res == 0)
-                        bd_finish_claiming(bdev, whole, filp);
-                else
-                        bd_abort_claiming(whole, filp);
-        }
-
-        return res;
+        return blkdev_get(bdev, filp->f_mode, filp);
 }
 
 static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
@@ -1539,6 +1322,7 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
                 bdev->bd_part_count--;
 
         if (!--bdev->bd_openers) {
+                WARN_ON_ONCE(bdev->bd_holders);
                 sync_blockdev(bdev);
                 kill_bdev(bdev);
         }
@@ -1569,6 +1353,45 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 
 int blkdev_put(struct block_device *bdev, fmode_t mode)
 {
+        if (mode & FMODE_EXCL) {
+                bool bdev_free;
+
+                /*
+                 * Release a claim on the device.  The holder fields
+                 * are protected with bdev_lock.  bd_mutex is to
+                 * synchronize disk_holder unlinking.
+                 */
+                mutex_lock(&bdev->bd_mutex);
+                spin_lock(&bdev_lock);
+
+                WARN_ON_ONCE(--bdev->bd_holders < 0);
+                WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0);
+
+                /* bd_contains might point to self, check in a separate step */
+                if ((bdev_free = !bdev->bd_holders))
+                        bdev->bd_holder = NULL;
+                if (!bdev->bd_contains->bd_holders)
+                        bdev->bd_contains->bd_holder = NULL;
+
+                spin_unlock(&bdev_lock);
+
+                /*
+                 * If this was the last claim, remove holder link and
+                 * unblock evpoll if it was a write holder.
+                 */
+                if (bdev_free) {
+                        bd_unlink_disk_holder(bdev);
+                        if (bdev->bd_write_holder) {
+                                disk_unblock_events(bdev->bd_disk);
+                                bdev->bd_write_holder = false;
+                        } else
+                                disk_check_events(bdev->bd_disk);
+                }
+
+                mutex_unlock(&bdev->bd_mutex);
+        } else
+                disk_check_events(bdev->bd_disk);
+
         return __blkdev_put(bdev, mode, 0);
 }
 EXPORT_SYMBOL(blkdev_put);
@@ -1576,8 +1399,7 @@ EXPORT_SYMBOL(blkdev_put);
 static int blkdev_close(struct inode * inode, struct file * filp)
 {
         struct block_device *bdev = I_BDEV(filp->f_mapping->host);
-        if (bdev->bd_holder == filp)
-                bd_release(bdev);
+
         return blkdev_put(bdev, filp->f_mode);
 }
 
@@ -1722,67 +1544,6 @@ fail:
 }
 EXPORT_SYMBOL(lookup_bdev);
 
-/**
- * open_bdev_exclusive  -  open a block device by name and set it up for use
- *
- * @path:       special file representing the block device
- * @mode:       FMODE_... combination to pass be used
- * @holder:     owner for exclusion
- *
- * Open the blockdevice described by the special file at @path, claim it
- * for the @holder.
- */
-struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder)
-{
-        struct block_device *bdev, *whole;
-        int error;
-
-        bdev = lookup_bdev(path);
-        if (IS_ERR(bdev))
-                return bdev;
-
-        whole = bd_start_claiming(bdev, holder);
-        if (IS_ERR(whole)) {
-                bdput(bdev);
-                return whole;
-        }
-
-        error = blkdev_get(bdev, mode);
-        if (error)
-                goto out_abort_claiming;
-
-        error = -EACCES;
-        if ((mode & FMODE_WRITE) && bdev_read_only(bdev))
-                goto out_blkdev_put;
-
-        bd_finish_claiming(bdev, whole, holder);
-        return bdev;
-
-out_blkdev_put:
-        blkdev_put(bdev, mode);
-out_abort_claiming:
-        bd_abort_claiming(whole, holder);
-        return ERR_PTR(error);
-}
-
-EXPORT_SYMBOL(open_bdev_exclusive);
-
-/**
- * close_bdev_exclusive  -  close a blockdevice opened by open_bdev_exclusive()
- *
- * @bdev:       blockdevice to close
- * @mode:       mode, must match that used to open.
- *
- * This is the counterpart to open_bdev_exclusive().
- */
-void close_bdev_exclusive(struct block_device *bdev, fmode_t mode)
-{
-        bd_release(bdev);
-        blkdev_put(bdev, mode);
-}
-
-EXPORT_SYMBOL(close_bdev_exclusive);
-
 int __invalidate_device(struct block_device *bdev)
 {
         struct super_block *sb = get_super(bdev);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 6b9884507837..1718e1a5c320 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -493,7 +493,7 @@ again:
                         continue;
 
                 if (device->bdev) {
-                        close_bdev_exclusive(device->bdev, device->mode);
+                        blkdev_put(device->bdev, device->mode);
                         device->bdev = NULL;
                         fs_devices->open_devices--;
                 }
@@ -527,7 +527,7 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 
         list_for_each_entry(device, &fs_devices->devices, dev_list) {
                 if (device->bdev) {
-                        close_bdev_exclusive(device->bdev, device->mode);
+                        blkdev_put(device->bdev, device->mode);
                         fs_devices->open_devices--;
                 }
                 if (device->writeable) {
@@ -584,13 +584,15 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
         int seeding = 1;
         int ret = 0;
 
+        flags |= FMODE_EXCL;
+
         list_for_each_entry(device, head, dev_list) {
                 if (device->bdev)
                         continue;
                 if (!device->name)
                         continue;
 
-                bdev = open_bdev_exclusive(device->name, flags, holder);
+                bdev = blkdev_get_by_path(device->name, flags, holder);
                 if (IS_ERR(bdev)) {
                         printk(KERN_INFO "open %s failed\n", device->name);
                         goto error;
@@ -642,7 +644,7 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 error_brelse:
                 brelse(bh);
 error_close:
-                close_bdev_exclusive(bdev, FMODE_READ);
+                blkdev_put(bdev, flags);
 error:
                 continue;
         }
@@ -688,7 +690,8 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 
         mutex_lock(&uuid_mutex);
 
-        bdev = open_bdev_exclusive(path, flags, holder);
+        flags |= FMODE_EXCL;
+        bdev = blkdev_get_by_path(path, flags, holder);
 
         if (IS_ERR(bdev)) {
                 ret = PTR_ERR(bdev);
@@ -720,7 +723,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 
         brelse(bh);
 error_close:
-        close_bdev_exclusive(bdev, flags);
+        blkdev_put(bdev, flags);
 error:
         mutex_unlock(&uuid_mutex);
         return ret;
@@ -1183,8 +1186,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
                         goto out;
                 }
         } else {
-                bdev = open_bdev_exclusive(device_path, FMODE_READ,
-                                      root->fs_info->bdev_holder);
+                bdev = blkdev_get_by_path(device_path, FMODE_READ | FMODE_EXCL,
+                                          root->fs_info->bdev_holder);
                 if (IS_ERR(bdev)) {
                         ret = PTR_ERR(bdev);
                         goto out;
@@ -1251,7 +1254,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
 
         if (device->bdev) {
-                close_bdev_exclusive(device->bdev, device->mode);
+                blkdev_put(device->bdev, device->mode);
                 device->bdev = NULL;
                 device->fs_devices->open_devices--;
         }
@@ -1294,7 +1297,7 @@ error_brelse:
         brelse(bh);
 error_close:
         if (bdev)
-                close_bdev_exclusive(bdev, FMODE_READ);
+                blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
 out:
         mutex_unlock(&root->fs_info->volume_mutex);
         mutex_unlock(&uuid_mutex);
@@ -1446,7 +1449,8 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
                 return -EINVAL;
 
-        bdev = open_bdev_exclusive(device_path, 0, root->fs_info->bdev_holder);
+        bdev = blkdev_get_by_path(device_path, FMODE_EXCL,
+                                  root->fs_info->bdev_holder);
         if (IS_ERR(bdev))
                 return PTR_ERR(bdev);
 
@@ -1572,7 +1576,7 @@ out:
         mutex_unlock(&root->fs_info->volume_mutex);
         return ret;
 error:
-        close_bdev_exclusive(bdev, 0);
+        blkdev_put(bdev, FMODE_EXCL);
         if (seeding_dev) {
                 mutex_unlock(&uuid_mutex);
                 up_write(&sb->s_umount);
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 2740db49eb04..1be781079450 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -50,7 +50,7 @@ struct btrfs_device {
 
         struct block_device *bdev;
 
-        /* the mode sent to open_bdev_exclusive */
+        /* the mode sent to blkdev_get */
         fmode_t mode;
 
         char *name;
diff --git a/fs/char_dev.c b/fs/char_dev.c
index 6e99b9ddd4e9..dca9e5e0f73b 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -59,7 +59,7 @@ static struct char_device_struct {
 } *chrdevs[CHRDEV_MAJOR_HASH_SIZE];
 
 /* index in the above */
-static inline int major_to_index(int major)
+static inline int major_to_index(unsigned major)
 {
         return major % CHRDEV_MAJOR_HASH_SIZE;
 }
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index b7d0554631e4..7aa767d4f06f 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -364,7 +364,7 @@ static struct block_device *ext3_blkdev_get(dev_t dev, struct super_block *sb)
         struct block_device *bdev;
         char b[BDEVNAME_SIZE];
 
-        bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
+        bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
         if (IS_ERR(bdev))
                 goto fail;
         return bdev;
@@ -381,8 +381,7 @@ fail:
  */
 static int ext3_blkdev_put(struct block_device *bdev)
 {
-        bd_release(bdev);
-        return blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
+        return blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
 }
 
 static int ext3_blkdev_remove(struct ext3_sb_info *sbi)
@@ -2162,13 +2161,6 @@ static journal_t *ext3_get_dev_journal(struct super_block *sb,
         if (bdev == NULL)
                 return NULL;
 
-        if (bd_claim(bdev, sb)) {
-                ext3_msg(sb, KERN_ERR,
-                        "error: failed to claim external journal device");
-                blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
-                return NULL;
-        }
-
         blocksize = sb->s_blocksize;
         hblock = bdev_logical_block_size(bdev);
         if (blocksize < hblock) {
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 29c80f6d8b27..cb10a06775e4 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -657,7 +657,7 @@ static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
         struct block_device *bdev;
         char b[BDEVNAME_SIZE];
 
-        bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
+        bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
         if (IS_ERR(bdev))
                 goto fail;
         return bdev;
@@ -673,8 +673,7 @@ fail:
  */
 static int ext4_blkdev_put(struct block_device *bdev)
 {
-        bd_release(bdev);
-        return blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
+        return blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
 }
 
 static int ext4_blkdev_remove(struct ext4_sb_info *sbi)
@@ -3778,13 +3777,6 @@ static journal_t *ext4_get_dev_journal(struct super_block *sb,
         if (bdev == NULL)
                 return NULL;
 
-        if (bd_claim(bdev, sb)) {
-                ext4_msg(sb, KERN_ERR,
-                        "failed to claim external journal device");
-                blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
-                return NULL;
-        }
-
         blocksize = sb->s_blocksize;
         hblock = bdev_logical_block_size(bdev);
         if (blocksize < hblock) {
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 693f4470a2df..777927ce6f79 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1268,7 +1268,7 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
 {
         struct block_device *bdev;
         struct super_block *s;
-        fmode_t mode = FMODE_READ;
+        fmode_t mode = FMODE_READ | FMODE_EXCL;
         int error;
         struct gfs2_args args;
         struct gfs2_sbd *sdp;
@@ -1276,7 +1276,7 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
         if (!(flags & MS_RDONLY))
                 mode |= FMODE_WRITE;
 
-        bdev = open_bdev_exclusive(dev_name, mode, fs_type);
+        bdev = blkdev_get_by_path(dev_name, mode, fs_type);
         if (IS_ERR(bdev))
                 return ERR_CAST(bdev);
 
@@ -1298,7 +1298,7 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
                 goto error_bdev;
 
         if (s->s_root)
-                close_bdev_exclusive(bdev, mode);
+                blkdev_put(bdev, mode);
 
         memset(&args, 0, sizeof(args));
         args.ar_quota = GFS2_QUOTA_DEFAULT;
@@ -1342,7 +1342,7 @@ error_super:
         deactivate_locked_super(s);
         return ERR_PTR(error);
 error_bdev:
-        close_bdev_exclusive(bdev, mode);
+        blkdev_put(bdev, mode);
         return ERR_PTR(error);
 }
 
diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index e1b8493b9aaa..278e3fb40b71 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1120,16 +1120,13 @@ int lmLogOpen(struct super_block *sb)
          * file systems to log may have n-to-1 relationship;
          */
 
-        bdev = open_by_devnum(sbi->logdev, FMODE_READ|FMODE_WRITE);
+        bdev = blkdev_get_by_dev(sbi->logdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
+                                 log);
         if (IS_ERR(bdev)) {
                 rc = -PTR_ERR(bdev);
                 goto free;
         }
 
-        if ((rc = bd_claim(bdev, log))) {
-                goto close;
-        }
-
         log->bdev = bdev;
         memcpy(log->uuid, sbi->loguuid, sizeof(log->uuid));
 
@@ -1137,7 +1134,7 @@ int lmLogOpen(struct super_block *sb)
          * initialize log:
          */
         if ((rc = lmLogInit(log)))
-                goto unclaim;
+                goto close;
 
         list_add(&log->journal_list, &jfs_external_logs);
 
@@ -1163,11 +1160,8 @@ journal_found:
         list_del(&log->journal_list);
         lbmLogShutdown(log);
 
-      unclaim:
-        bd_release(bdev);
-
       close:            /* close external log device */
-        blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
+        blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
 
       free:             /* free log descriptor */
         mutex_unlock(&jfs_log_mutex);
@@ -1512,8 +1506,7 @@ int lmLogClose(struct super_block *sb)
         bdev = log->bdev;
         rc = lmLogShutdown(log);
 
-        bd_release(bdev);
-        blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
+        blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
 
         kfree(log);
 
diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c
index 92ca6fbe09bd..723bc5bca09a 100644
--- a/fs/logfs/dev_bdev.c
+++ b/fs/logfs/dev_bdev.c
@@ -300,7 +300,7 @@ static int bdev_write_sb(struct super_block *sb, struct page *page)
 
 static void bdev_put_device(struct logfs_super *s)
 {
-        close_bdev_exclusive(s->s_bdev, FMODE_READ|FMODE_WRITE);
+        blkdev_put(s->s_bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
 }
 
 static int bdev_can_write_buf(struct super_block *sb, u64 ofs)
@@ -325,13 +325,14 @@ int logfs_get_sb_bdev(struct logfs_super *p, struct file_system_type *type,
 {
         struct block_device *bdev;
 
-        bdev = open_bdev_exclusive(devname, FMODE_READ|FMODE_WRITE, type);
+        bdev = blkdev_get_by_path(devname, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
+                                  type);
         if (IS_ERR(bdev))
                 return PTR_ERR(bdev);
 
         if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
                 int mtdnr = MINOR(bdev->bd_dev);
-                close_bdev_exclusive(bdev, FMODE_READ|FMODE_WRITE);
+                blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
                 return logfs_get_sb_mtd(p, mtdnr);
         }
 
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 3a359023c9f7..230b79fbf005 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -845,11 +845,6 @@ nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
         struct page **pp = rqstp->rq_respages + rqstp->rq_resused;
         struct page *page = buf->page;
         size_t size;
-        int ret;
-
-        ret = buf->ops->confirm(pipe, buf);
-        if (unlikely(ret))
-                return ret;
 
         size = sd->len;
 
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 70dfdd532b83..0994f6a76c07 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -1163,14 +1163,14 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
 {
         struct nilfs_super_data sd;
         struct super_block *s;
-        fmode_t mode = FMODE_READ;
+        fmode_t mode = FMODE_READ | FMODE_EXCL;
         struct dentry *root_dentry;
         int err, s_new = false;
 
         if (!(flags & MS_RDONLY))
                 mode |= FMODE_WRITE;
 
-        sd.bdev = open_bdev_exclusive(dev_name, mode, fs_type);
+        sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
         if (IS_ERR(sd.bdev))
                 return ERR_CAST(sd.bdev);
 
@@ -1249,7 +1249,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
         }
 
         if (!s_new)
-                close_bdev_exclusive(sd.bdev, mode);
+                blkdev_put(sd.bdev, mode);
 
         return root_dentry;
 
@@ -1258,7 +1258,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
 
  failed:
         if (!s_new)
-                close_bdev_exclusive(sd.bdev, mode);
+                blkdev_put(sd.bdev, mode);
         return ERR_PTR(err);
 }
 
diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index a6cc05302e9f..b108e863d8f6 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -1729,7 +1729,7 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
                 goto out;
 
         reg->hr_bdev = I_BDEV(filp->f_mapping->host);
-        ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ);
+        ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ, NULL);
         if (ret) {
                 reg->hr_bdev = NULL;
                 goto out;
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 0a8b0ad0c7e2..9c21119512b9 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -237,6 +237,13 @@ ssize_t part_size_show(struct device *dev,
         return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects);
 }
 
+ssize_t part_ro_show(struct device *dev,
+                       struct device_attribute *attr, char *buf)
+{
+        struct hd_struct *p = dev_to_part(dev);
+        return sprintf(buf, "%d\n", p->policy ? 1 : 0);
+}
+
 ssize_t part_alignment_offset_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
 {
@@ -312,6 +319,7 @@ ssize_t part_fail_store(struct device *dev,
 static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
 static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
+static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
 static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
 static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
                    NULL);
@@ -326,6 +334,7 @@ static struct attribute *part_attrs[] = {
         &dev_attr_partition.attr,
         &dev_attr_start.attr,
         &dev_attr_size.attr,
+        &dev_attr_ro.attr,
         &dev_attr_alignment_offset.attr,
         &dev_attr_discard_alignment.attr,
         &dev_attr_stat.attr,
@@ -372,6 +381,11 @@ static void delete_partition_rcu_cb(struct rcu_head *head)
         put_device(part_to_dev(part));
 }
 
+void __delete_partition(struct hd_struct *part)
+{
+        call_rcu(&part->rcu_head, delete_partition_rcu_cb);
+}
+
 void delete_partition(struct gendisk *disk, int partno)
 {
         struct disk_part_tbl *ptbl = disk->part_tbl;
@@ -390,7 +404,7 @@ void delete_partition(struct gendisk *disk, int partno)
         kobject_put(part->holder_dir);
         device_del(part_to_dev(part));
 
-        call_rcu(&part->rcu_head, delete_partition_rcu_cb);
+        hd_struct_put(part);
 }
 
 static ssize_t whole_disk_show(struct device *dev,
@@ -489,6 +503,7 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
         if (!dev_get_uevent_suppress(ddev))
                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
 
+        hd_ref_init(p);
         return p;
 
 out_free_info:
@@ -507,65 +522,6 @@ out_put:
         return ERR_PTR(err);
 }
 
-/* Not exported, helper to add_disk(). */
-void register_disk(struct gendisk *disk)
-{
-        struct device *ddev = disk_to_dev(disk);
-        struct block_device *bdev;
-        struct disk_part_iter piter;
-        struct hd_struct *part;
-        int err;
-
-        ddev->parent = disk->driverfs_dev;
-
-        dev_set_name(ddev, disk->disk_name);
-
-        /* delay uevents, until we scanned partition table */
-        dev_set_uevent_suppress(ddev, 1);
-
-        if (device_add(ddev))
-                return;
-        if (!sysfs_deprecated) {
-                err = sysfs_create_link(block_depr, &ddev->kobj,
-                                        kobject_name(&ddev->kobj));
-                if (err) {
-                        device_del(ddev);
-                        return;
-                }
-        }
-        disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
-        disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
-
-        /* No minors to use for partitions */
-        if (!disk_partitionable(disk))
-                goto exit;
-
-        /* No such device (e.g., media were just removed) */
-        if (!get_capacity(disk))
-                goto exit;
-
-        bdev = bdget_disk(disk, 0);
-        if (!bdev)
-                goto exit;
-
-        bdev->bd_invalidated = 1;
-        err = blkdev_get(bdev, FMODE_READ);
-        if (err < 0)
-                goto exit;
-        blkdev_put(bdev, FMODE_READ);
-
-exit:
-        /* announce disk after possible partitions are created */
-        dev_set_uevent_suppress(ddev, 0);
-        kobject_uevent(&ddev->kobj, KOBJ_ADD);
-
-        /* announce possible partitions */
-        disk_part_iter_init(&piter, disk, 0);
-        while ((part = disk_part_iter_next(&piter)))
-                kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
-        disk_part_iter_exit(&piter);
-}
-
 static bool disk_unlock_native_capacity(struct gendisk *disk)
 {
         const struct block_device_operations *bdops = disk->fops;
@@ -728,33 +684,3 @@ fail:
 }
 
 EXPORT_SYMBOL(read_dev_sector);
-
-void del_gendisk(struct gendisk *disk)
-{
-        struct disk_part_iter piter;
-        struct hd_struct *part;
-
-        /* invalidate stuff */
-        disk_part_iter_init(&piter, disk,
-                             DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
-        while ((part = disk_part_iter_next(&piter))) {
-                invalidate_partition(disk, part->partno);
-                delete_partition(disk, part->partno);
-        }
-        disk_part_iter_exit(&piter);
-
-        invalidate_partition(disk, 0);
-        blk_free_devt(disk_to_dev(disk)->devt);
-        set_capacity(disk, 0);
-        disk->flags &= ~GENHD_FL_UP;
-        unlink_gendisk(disk);
-        part_stat_set_all(&disk->part0, 0);
-        disk->part0.stamp = 0;
-
-        kobject_put(disk->part0.holder_dir);
-        kobject_put(disk->slave_dir);
-        disk->driverfs_dev = NULL;
-        if (!sysfs_deprecated)
-                sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
-        device_del(disk_to_dev(disk));
-}
diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index d31bce1a9f90..3eea859e6990 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -2551,8 +2551,6 @@ static int release_journal_dev(struct super_block *super,
         result = 0;
 
         if (journal->j_dev_bd != NULL) {
-                if (journal->j_dev_bd->bd_dev != super->s_dev)
-                        bd_release(journal->j_dev_bd);
                 result = blkdev_put(journal->j_dev_bd, journal->j_dev_mode);
                 journal->j_dev_bd = NULL;
         }
@@ -2570,7 +2568,7 @@ static int journal_init_dev(struct super_block *super,
 {
         int result;
         dev_t jdev;
-        fmode_t blkdev_mode = FMODE_READ | FMODE_WRITE;
+        fmode_t blkdev_mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
         char b[BDEVNAME_SIZE];
 
         result = 0;
@@ -2584,7 +2582,10 @@ static int journal_init_dev(struct super_block *super,
 
         /* there is no "jdev" option and journal is on separate device */
         if ((!jdev_name || !jdev_name[0])) {
-                journal->j_dev_bd = open_by_devnum(jdev, blkdev_mode);
+                if (jdev == super->s_dev)
+                        blkdev_mode &= ~FMODE_EXCL;
+                journal->j_dev_bd = blkdev_get_by_dev(jdev, blkdev_mode,
+                                                      journal);
                 journal->j_dev_mode = blkdev_mode;
                 if (IS_ERR(journal->j_dev_bd)) {
                         result = PTR_ERR(journal->j_dev_bd);
@@ -2593,22 +2594,14 @@ static int journal_init_dev(struct super_block *super,
                                          "cannot init journal device '%s': %i",
                                          __bdevname(jdev, b), result);
                         return result;
-                } else if (jdev != super->s_dev) {
-                        result = bd_claim(journal->j_dev_bd, journal);
-                        if (result) {
-                                blkdev_put(journal->j_dev_bd, blkdev_mode);
-                                return result;
-                        }
-
+                } else if (jdev != super->s_dev)
                         set_blocksize(journal->j_dev_bd, super->s_blocksize);
-                }
 
                 return 0;
         }
 
         journal->j_dev_mode = blkdev_mode;
-        journal->j_dev_bd = open_bdev_exclusive(jdev_name,
-                                                blkdev_mode, journal);
+        journal->j_dev_bd = blkdev_get_by_path(jdev_name, blkdev_mode, journal);
         if (IS_ERR(journal->j_dev_bd)) {
                 result = PTR_ERR(journal->j_dev_bd);
                 journal->j_dev_bd = NULL;
diff --git a/fs/splice.c b/fs/splice.c
index ce2f02579e35..50a5d978da16 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -682,19 +682,14 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe,
 {
         struct file *file = sd->u.file;
         loff_t pos = sd->pos;
-        int ret, more;
-
-        ret = buf->ops->confirm(pipe, buf);
-        if (!ret) {
-                more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
-                if (file->f_op && file->f_op->sendpage)
-                        ret = file->f_op->sendpage(file, buf->page, buf->offset,
-                                                   sd->len, &pos, more);
-                else
-                        ret = -EINVAL;
-        }
+        int more;
 
-        return ret;
+        if (!likely(file->f_op && file->f_op->sendpage))
+                return -EINVAL;
+
+        more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
+        return file->f_op->sendpage(file, buf->page, buf->offset,
+                                    sd->len, &pos, more);
 }
 
 /*
@@ -727,13 +722,6 @@ int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
         void *fsdata;
         int ret;
 
-        /*
-         * make sure the data in this buffer is uptodate
-         */
-        ret = buf->ops->confirm(pipe, buf);
-        if (unlikely(ret))
-                return ret;
-
         offset = sd->pos & ~PAGE_CACHE_MASK;
 
         this_len = sd->len;
@@ -805,12 +793,17 @@ int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd,
                 if (sd->len > sd->total_len)
                         sd->len = sd->total_len;
 
-                ret = actor(pipe, buf, sd);
-                if (ret <= 0) {
+                ret = buf->ops->confirm(pipe, buf);
+                if (unlikely(ret)) {
                         if (ret == -ENODATA)
                                 ret = 0;
                         return ret;
                 }
+
+                ret = actor(pipe, buf, sd);
+                if (ret <= 0)
+                        return ret;
+
                 buf->offset += ret;
                 buf->len -= ret;
 
@@ -1044,10 +1037,6 @@ static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
         int ret;
         void *data;
 
-        ret = buf->ops->confirm(pipe, buf);
-        if (ret)
-                return ret;
-
         data = buf->ops->map(pipe, buf, 0);
         ret = kernel_write(sd->u.file, data + buf->offset, sd->len, sd->pos);
         buf->ops->unmap(pipe, buf, data);
@@ -1495,10 +1484,6 @@ static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
         char *src;
         int ret;
 
-        ret = buf->ops->confirm(pipe, buf);
-        if (unlikely(ret))
-                return ret;
-
         /*
          * See if we can use the atomic maps, by prefaulting in the
          * pages and doing an atomic copy
diff --git a/fs/super.c b/fs/super.c
index 823e061faa87..4f6a3571a634 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -767,13 +767,13 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
 {
         struct block_device *bdev;
         struct super_block *s;
-        fmode_t mode = FMODE_READ;
+        fmode_t mode = FMODE_READ | FMODE_EXCL;
         int error = 0;
 
         if (!(flags & MS_RDONLY))
                 mode |= FMODE_WRITE;
 
-        bdev = open_bdev_exclusive(dev_name, mode, fs_type);
+        bdev = blkdev_get_by_path(dev_name, mode, fs_type);
         if (IS_ERR(bdev))
                 return ERR_CAST(bdev);
 
@@ -802,13 +802,13 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
 
                 /*
                  * s_umount nests inside bd_mutex during
-                 * __invalidate_device().  close_bdev_exclusive()
-                 * acquires bd_mutex and can't be called under
-                 * s_umount.  Drop s_umount temporarily.  This is safe
-                 * as we're holding an active reference.
+                 * __invalidate_device().  blkdev_put() acquires
+                 * bd_mutex and can't be called under s_umount.  Drop
+                 * s_umount temporarily.  This is safe as we're
+                 * holding an active reference.
                  */
                 up_write(&s->s_umount);
-                close_bdev_exclusive(bdev, mode);
+                blkdev_put(bdev, mode);
                 down_write(&s->s_umount);
         } else {
                 char b[BDEVNAME_SIZE];
@@ -832,7 +832,7 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
 error_s:
         error = PTR_ERR(s);
 error_bdev:
-        close_bdev_exclusive(bdev, mode);
+        blkdev_put(bdev, mode);
 error:
         return ERR_PTR(error);
 }
@@ -863,7 +863,8 @@ void kill_block_super(struct super_block *sb)
         bdev->bd_super = NULL;
         generic_shutdown_super(sb);
         sync_blockdev(bdev);
-        close_bdev_exclusive(bdev, mode);
+        WARN_ON_ONCE(!(mode & FMODE_EXCL));
+        blkdev_put(bdev, mode | FMODE_EXCL);
 }
 
 EXPORT_SYMBOL(kill_block_super);
diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index a10f6416e563..bd07f7339366 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -606,7 +606,8 @@ xfs_blkdev_get(
 {
         int                     error = 0;
 
-        *bdevp = open_bdev_exclusive(name, FMODE_READ|FMODE_WRITE, mp);
+        *bdevp = blkdev_get_by_path(name, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
+                                    mp);
         if (IS_ERR(*bdevp)) {
                 error = PTR_ERR(*bdevp);
                 printk("XFS: Invalid device [%s], error=%d\n", name, error);
@@ -620,7 +621,7 @@ xfs_blkdev_put(
         struct block_device     *bdev)
 {
         if (bdev)
-                close_bdev_exclusive(bdev, FMODE_READ|FMODE_WRITE);
+                blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
 }
 
 /*
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 36ab42c9bb99..4d18ff34670a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -115,6 +115,7 @@ struct request {
         void *elevator_private3;
 
         struct gendisk *rq_disk;
+        struct hd_struct *part;
         unsigned long start_time;
 #ifdef CONFIG_BLK_CGROUP
         unsigned long long start_time_ns;
@@ -646,7 +647,6 @@ static inline void rq_flush_dcache_pages(struct request *rq)
 
 extern int blk_register_queue(struct gendisk *disk);
 extern void blk_unregister_queue(struct gendisk *disk);
-extern void register_disk(struct gendisk *dev);
 extern void generic_make_request(struct bio *bio);
 extern void blk_rq_init(struct request_queue *q, struct request *rq);
 extern void blk_put_request(struct request *);
@@ -1256,6 +1256,9 @@ struct block_device_operations {
         int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
         int (*direct_access) (struct block_device *, sector_t,
                                                 void **, unsigned long *);
+        unsigned int (*check_events) (struct gendisk *disk,
+                                      unsigned int clearing);
+        /* ->media_changed() is DEPRECATED, use ->check_events() instead */
         int (*media_changed) (struct gendisk *);
         void (*unlock_native_capacity) (struct gendisk *);
         int (*revalidate_disk) (struct gendisk *);
diff --git a/include/linux/cdrom.h b/include/linux/cdrom.h
index 78e904796622..35eae4b67503 100644
--- a/include/linux/cdrom.h
+++ b/include/linux/cdrom.h
@@ -946,6 +946,8 @@ struct cdrom_device_info {
 /* device-related storage */
         unsigned int options    : 30;   /* options flags */
         unsigned mc_flags       : 2;    /* media change buffer flags */
+        unsigned int vfs_events;        /* cached events for vfs path */
+        unsigned int ioctl_events;      /* cached events for ioctl path */
         int use_count;                  /* number of times device opened */
         char name[20];                  /* name of the device type */
 /* per-device flags */
@@ -965,6 +967,8 @@ struct cdrom_device_ops {
         int (*open) (struct cdrom_device_info *, int);
         void (*release) (struct cdrom_device_info *);
         int (*drive_status) (struct cdrom_device_info *, int);
+        unsigned int (*check_events) (struct cdrom_device_info *cdi,
+                                      unsigned int clearing, int slot);
         int (*media_changed) (struct cdrom_device_info *, int);
         int (*tray_move) (struct cdrom_device_info *, int);
         int (*lock_door) (struct cdrom_device_info *, int);
@@ -993,6 +997,8 @@ extern int cdrom_open(struct cdrom_device_info *cdi, struct block_device *bdev,
 extern void cdrom_release(struct cdrom_device_info *cdi, fmode_t mode);
 extern int cdrom_ioctl(struct cdrom_device_info *cdi, struct block_device *bdev,
                        fmode_t mode, unsigned int cmd, unsigned long arg);
+extern unsigned int cdrom_check_events(struct cdrom_device_info *cdi,
+                                       unsigned int clearing);
 extern int cdrom_media_changed(struct cdrom_device_info *);
 
 extern int register_cdrom(struct cdrom_device_info *cdi);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c0701288d204..3984f2358d1f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -664,8 +664,9 @@ struct block_device {
         void *                  bd_claiming;
         void *                  bd_holder;
         int                     bd_holders;
+        bool                    bd_write_holder;
 #ifdef CONFIG_SYSFS
-        struct list_head        bd_holder_list;
+        struct gendisk *        bd_holder_disk; /* for sysfs slave linkng */
 #endif
         struct block_device *   bd_contains;
         unsigned                bd_block_size;
@@ -2019,7 +2020,6 @@ extern struct block_device *bdgrab(struct block_device *bdev);
 extern void bd_set_size(struct block_device *, loff_t size);
 extern void bd_forget(struct inode *inode);
 extern void bdput(struct block_device *);
-extern struct block_device *open_by_devnum(dev_t, fmode_t);
 extern void invalidate_bdev(struct block_device *);
 extern int sync_blockdev(struct block_device *bdev);
 extern struct super_block *freeze_bdev(struct block_device *);
@@ -2050,16 +2050,20 @@ extern const struct file_operations def_fifo_fops;
 extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
 extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
 extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
-extern int blkdev_get(struct block_device *, fmode_t);
-extern int blkdev_put(struct block_device *, fmode_t);
-extern int bd_claim(struct block_device *, void *);
-extern void bd_release(struct block_device *);
+extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
+extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
+                                               void *holder);
+extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode,
+                                              void *holder);
+extern int blkdev_put(struct block_device *bdev, fmode_t mode);
 #ifdef CONFIG_SYSFS
-extern int bd_claim_by_disk(struct block_device *, void *, struct gendisk *);
-extern void bd_release_from_disk(struct block_device *, struct gendisk *);
+extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
 #else
-#define bd_claim_by_disk(bdev, holder, disk)    bd_claim(bdev, holder)
-#define bd_release_from_disk(bdev, disk)        bd_release(bdev)
+static inline int bd_link_disk_holder(struct block_device *bdev,
+                                      struct gendisk *disk)
+{
+        return 0;
+}
 #endif
 #endif
 
@@ -2095,8 +2099,6 @@ static inline void unregister_chrdev(unsigned int major, const char *name)
 extern const char *__bdevname(dev_t, char *buffer);
 extern const char *bdevname(struct block_device *bdev, char *buffer);
 extern struct block_device *lookup_bdev(const char *);
-extern struct block_device *open_bdev_exclusive(const char *, fmode_t, void *);
-extern void close_bdev_exclusive(struct block_device *, fmode_t);
 extern void blkdev_show(struct seq_file *,off_t);
 
 #else
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 7a7b9c1644e4..c0d5f6945c1e 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -115,6 +115,7 @@ struct hd_struct {
 #else
         struct disk_stats dkstats;
 #endif
+        atomic_t ref;
         struct rcu_head rcu_head;
 };
 
@@ -127,6 +128,11 @@ struct hd_struct {
 #define GENHD_FL_EXT_DEVT                       64 /* allow extended devt */
 #define GENHD_FL_NATIVE_CAPACITY                128
 
+enum {
+        DISK_EVENT_MEDIA_CHANGE                 = 1 << 0, /* media changed */
+        DISK_EVENT_EJECT_REQUEST                = 1 << 1, /* eject requested */
+};
+
 #define BLK_SCSI_MAX_CMDS       (256)
 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
 
@@ -143,6 +149,8 @@ struct disk_part_tbl {
         struct hd_struct __rcu *part[];
 };
 
+struct disk_events;
+
 struct gendisk {
         /* major, first_minor and minors are input parameters only,
          * don't use directly.  Use disk_devt() and disk_max_parts().
@@ -154,6 +162,10 @@ struct gendisk {
 
         char disk_name[DISK_NAME_LEN];  /* name of major driver */
         char *(*devnode)(struct gendisk *gd, mode_t *mode);
+
+        unsigned int events;            /* supported events */
+        unsigned int async_events;      /* async events, subset of all */
+
         /* Array of pointers to partitions indexed by partno.
          * Protected with matching bdev lock but stat and other
          * non-critical accesses use RCU.  Always access through
@@ -171,9 +183,8 @@ struct gendisk {
         struct kobject *slave_dir;
 
         struct timer_rand_state *random;
-
         atomic_t sync_io;               /* RAID */
-        struct work_struct async_notify;
+        struct disk_events *ev;
 #ifdef  CONFIG_BLK_DEV_INTEGRITY
         struct blk_integrity *integrity;
 #endif
@@ -395,7 +406,6 @@ extern void part_round_stats(int cpu, struct hd_struct *part);
 /* block/genhd.c */
 extern void add_disk(struct gendisk *disk);
 extern void del_gendisk(struct gendisk *gp);
-extern void unlink_gendisk(struct gendisk *gp);
 extern struct gendisk *get_gendisk(dev_t dev, int *partno);
 extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
 
@@ -407,6 +417,11 @@ static inline int get_disk_ro(struct gendisk *disk)
         return disk->part0.policy;
 }
 
+extern void disk_block_events(struct gendisk *disk);
+extern void disk_unblock_events(struct gendisk *disk);
+extern void disk_check_events(struct gendisk *disk);
+extern unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask);
+
 /* drivers/char/random.c */
 extern void add_disk_randomness(struct gendisk *disk);
 extern void rand_initialize_disk(struct gendisk *disk);
@@ -583,6 +598,7 @@ extern struct hd_struct * __must_check add_partition(struct gendisk *disk,
                                                      sector_t len, int flags,
                                                      struct partition_meta_info
                                                        *info);
+extern void __delete_partition(struct hd_struct *);
 extern void delete_partition(struct gendisk *, int);
 extern void printk_all_partitions(void);
 
@@ -611,6 +627,29 @@ extern ssize_t part_fail_store(struct device *dev,
                                const char *buf, size_t count);
 #endif /* CONFIG_FAIL_MAKE_REQUEST */
 
+static inline void hd_ref_init(struct hd_struct *part)
+{
+        atomic_set(&part->ref, 1);
+        smp_mb();
+}
+
+static inline void hd_struct_get(struct hd_struct *part)
+{
+        atomic_inc(&part->ref);
+        smp_mb__after_atomic_inc();
+}
+
+static inline int hd_struct_try_get(struct hd_struct *part)
+{
+        return atomic_inc_not_zero(&part->ref);
+}
+
+static inline void hd_struct_put(struct hd_struct *part)
+{
+        if (atomic_dec_and_test(&part->ref))
+                __delete_partition(part);
+}
+
 #else /* CONFIG_BLOCK */
 
 static inline void printk_all_partitions(void) { }
diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 1651fef18831..648d23358038 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -104,6 +104,7 @@ struct scsi_cmnd;
 #define UNMAP                 0x42
 #define READ_TOC              0x43
 #define READ_HEADER           0x44
+#define GET_EVENT_STATUS_NOTIFICATION 0x4a
 #define LOG_SELECT            0x4c
 #define LOG_SENSE             0x4d
 #define XDWRITEREAD_10        0x53
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index d8ce278515c3..aba421d68f6f 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -206,15 +206,16 @@ TRACE_EVENT(block_bio_bounce,
  * block_bio_complete - completed all work on the block operation
  * @q: queue holding the block operation
  * @bio: block operation completed
+ * @error: io error value
  *
  * This tracepoint indicates there is no further work to do on this
  * block IO operation @bio.
  */
 TRACE_EVENT(block_bio_complete,
 
-        TP_PROTO(struct request_queue *q, struct bio *bio),
+        TP_PROTO(struct request_queue *q, struct bio *bio, int error),
 
-        TP_ARGS(q, bio),
+        TP_ARGS(q, bio, error),
 
         TP_STRUCT__entry(
                 __field( dev_t,         dev             )
@@ -228,6 +229,7 @@ TRACE_EVENT(block_bio_complete,
                 __entry->dev            = bio->bi_bdev->bd_dev;
                 __entry->sector         = bio->bi_sector;
                 __entry->nr_sector      = bio->bi_size >> 9;
+                __entry->error          = error;
                 blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
         ),
 
@@ -486,16 +488,16 @@ TRACE_EVENT(block_split,
 );
 
 /**
- * block_remap - map request for a partition to the raw device
+ * block_bio_remap - map request for a logical device to the raw device
  * @q: queue holding the operation
  * @bio: revised operation
  * @dev: device for the operation
  * @from: original sector for the operation
  *
- * An operation for a partition on a block device has been mapped to the
+ * An operation for a logical device has been mapped to the
  * raw block device.
  */
-TRACE_EVENT(block_remap,
+TRACE_EVENT(block_bio_remap,
 
         TP_PROTO(struct request_queue *q, struct bio *bio, dev_t dev,
                  sector_t from),
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 69425889bd40..7c97c3a0eee3 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -224,7 +224,7 @@ static int swsusp_swap_check(void)
                 return res;
 
         root_swap = res;
-        res = blkdev_get(hib_resume_bdev, FMODE_WRITE);
+        res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL);
         if (res)
                 return res;
 
@@ -930,7 +930,8 @@ int swsusp_check(void)
 {
         int error;
 
-        hib_resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
+        hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
+                                            FMODE_READ, NULL);
         if (!IS_ERR(hib_resume_bdev)) {
                 set_blocksize(hib_resume_bdev, PAGE_SIZE);
                 clear_page(swsusp_header);
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 7b8ec0281548..153562d0b93c 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -758,53 +758,58 @@ static void blk_add_trace_rq_complete(void *ignore,
  * @q:          queue the io is for
  * @bio:        the source bio
  * @what:       the action
+ * @error:      error, if any
  *
  * Description:
  *     Records an action against a bio. Will log the bio offset + size.
  *
  **/
 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
-                                     u32 what)
+                              u32 what, int error)
 {
         struct blk_trace *bt = q->blk_trace;
 
         if (likely(!bt))
                 return;
 
+        if (!error && !bio_flagged(bio, BIO_UPTODATE))
+                error = EIO;
+
         __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
-                        !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
+                        error, 0, NULL);
 }
 
 static void blk_add_trace_bio_bounce(void *ignore,
                                      struct request_queue *q, struct bio *bio)
 {
-        blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
+        blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
 }
 
 static void blk_add_trace_bio_complete(void *ignore,
-                                       struct request_queue *q, struct bio *bio)
+                                       struct request_queue *q, struct bio *bio,
+                                       int error)
 {
-        blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
+        blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
 }
 
 static void blk_add_trace_bio_backmerge(void *ignore,
                                         struct request_queue *q,
                                         struct bio *bio)
 {
-        blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
+        blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
 }
 
 static void blk_add_trace_bio_frontmerge(void *ignore,
                                          struct request_queue *q,
                                          struct bio *bio)
 {
-        blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
+        blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
 }
 
 static void blk_add_trace_bio_queue(void *ignore,
                                     struct request_queue *q, struct bio *bio)
 {
-        blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
+        blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
 }
 
 static void blk_add_trace_getrq(void *ignore,
@@ -812,7 +817,7 @@ static void blk_add_trace_getrq(void *ignore,
                                 struct bio *bio, int rw)
 {
         if (bio)
-                blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
+                blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
         else {
                 struct blk_trace *bt = q->blk_trace;
 
@@ -827,7 +832,7 @@ static void blk_add_trace_sleeprq(void *ignore,
                                   struct bio *bio, int rw)
 {
         if (bio)
-                blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
+                blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
         else {
                 struct blk_trace *bt = q->blk_trace;
 
@@ -887,7 +892,7 @@ static void blk_add_trace_split(void *ignore,
 }
 
 /**
- * blk_add_trace_remap - Add a trace for a remap operation
+ * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
  * @ignore:     trace callback data parameter (not used)
  * @q:          queue the io is for
  * @bio:        the source bio
@@ -899,9 +904,9 @@ static void blk_add_trace_split(void *ignore,
  *     it spans a stripe (or similar). Add a trace for that action.
  *
  **/
-static void blk_add_trace_remap(void *ignore,
-                                struct request_queue *q, struct bio *bio,
-                                dev_t dev, sector_t from)
+static void blk_add_trace_bio_remap(void *ignore,
+                                    struct request_queue *q, struct bio *bio,
+                                    dev_t dev, sector_t from)
 {
         struct blk_trace *bt = q->blk_trace;
         struct blk_io_trace_remap r;
@@ -1016,7 +1021,7 @@ static void blk_register_tracepoints(void)
         WARN_ON(ret);
         ret = register_trace_block_split(blk_add_trace_split, NULL);
         WARN_ON(ret);
-        ret = register_trace_block_remap(blk_add_trace_remap, NULL);
+        ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
         WARN_ON(ret);
         ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
         WARN_ON(ret);
@@ -1025,7 +1030,7 @@ static void blk_register_tracepoints(void)
 static void blk_unregister_tracepoints(void)
 {
         unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
-        unregister_trace_block_remap(blk_add_trace_remap, NULL);
+        unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
         unregister_trace_block_split(blk_add_trace_split, NULL);
         unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
         unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 67ddaaf98c74..b6adcfbf6f48 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1677,7 +1677,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
         if (S_ISBLK(inode->i_mode)) {
                 struct block_device *bdev = I_BDEV(inode);
                 set_blocksize(bdev, p->old_block_size);
-                bd_release(bdev);
+                blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
         } else {
                 mutex_lock(&inode->i_mutex);
                 inode->i_flags &= ~S_SWAPFILE;
@@ -1939,7 +1939,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
         error = -EINVAL;
         if (S_ISBLK(inode->i_mode)) {
                 bdev = I_BDEV(inode);
-                error = bd_claim(bdev, sys_swapon);
+                error = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL,
+                                   sys_swapon);
                 if (error < 0) {
                         bdev = NULL;
                         error = -EINVAL;
@@ -2136,7 +2137,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 bad_swap:
         if (bdev) {
                 set_blocksize(bdev, p->old_block_size);
-                bd_release(bdev);
+                blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
         }
         destroy_swap_extents(p);
         swap_cgroup_swapoff(type);