Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block

* 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block: (43 commits)
  block: ensure that completion error gets properly traced
  blktrace: add missing probe argument to block_bio_complete
  block cfq: don't use atomic_t for cfq_group
  block cfq: don't use atomic_t for cfq_queue
  block: trace event block fix unassigned field
  block: add internal hd part table references
  block: fix accounting bug on cross partition merges
  kref: add kref_test_and_get
  bio-integrity: mark kintegrityd_wq highpri and CPU intensive
  block: make kblockd_workqueue smarter
  Revert "sd: implement sd_check_events()"
  block: Clean up exit_io_context() source code.
  Fix compile warnings due to missing removal of a 'ret' variable
  fs/block: type signature of major_to_index(int) to major_to_index(unsigned)
  block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p)
  cfq-iosched: don't check cfqg in choose_service_tree()
  fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors
  cdrom: export cdrom_check_events()
  sd: implement sd_check_events()
  sr: implement sr_check_events()
  ...

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

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);

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");
 

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);
 }
 

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();
 	}
 }

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);

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);
+}

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);

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 */

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);
 }

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);

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);

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;
 

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;
 }

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;
 }
 

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;
 }
 

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) {

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);

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
 

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

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;

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;
 	}

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,

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 *);

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" */

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;
 	}

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");
 

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);

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);

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;

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;
 }

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) {

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) {

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);
 }
 

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);
 

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);
 	}
 

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;
 

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);
 }
 

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;

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));
-}

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;

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

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);

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);
 }
 
 /*

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 *);

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);

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

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) { }

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

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),

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);

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);

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);