block: use the holder as indication for exclusive opens

The current interface for exclusive opens is rather confusing as it
requires both the FMODE_EXCL flag and a holder.  Remove the need to pass
FMODE_EXCL and just key off the exclusive open off a non-NULL holder.

For blkdev_put this requires adding the holder argument, which provides
better debug checking that only the holder actually releases the hold,
but at the same time allows removing the now superfluous mode argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: David Sterba <dsterba@suse.com>		[btrfs]
Acked-by: Jack Wang <jinpu.wang@ionos.com>		[rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

37 files changed, 183 insertions, 192 deletions

diff --git a/block/bdev.c b/block/bdev.c
index 2c6888ceb378..db63e5bcc46f 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -604,7 +604,7 @@ void bd_abort_claiming(struct block_device *bdev, void *holder)
 }
 EXPORT_SYMBOL(bd_abort_claiming);
 
-static void bd_end_claim(struct block_device *bdev)
+static void bd_end_claim(struct block_device *bdev, void *holder)
 {
 	struct block_device *whole = bdev_whole(bdev);
 	bool unblock = false;
@@ -614,6 +614,7 @@ static void bd_end_claim(struct block_device *bdev)
 	 * bdev_lock.  open_mutex is used to synchronize disk_holder unlinking.
 	 */
 	mutex_lock(&bdev_lock);
+	WARN_ON_ONCE(bdev->bd_holder != holder);
 	WARN_ON_ONCE(--bdev->bd_holders < 0);
 	WARN_ON_ONCE(--whole->bd_holders < 0);
 	if (!bdev->bd_holders) {
@@ -750,10 +751,9 @@ void blkdev_put_no_open(struct block_device *bdev)
  * @holder: exclusive holder identifier
  * @hops: holder operations
  *
- * Open the block device described by device number @dev. If @mode includes
- * %FMODE_EXCL, the block device is opened with exclusive access.  Specifying
- * %FMODE_EXCL with a %NULL @holder is invalid.  Exclusive opens may nest for
- * the same @holder.
+ * Open the block device described by device number @dev. If @holder is not
+ * %NULL, the block device is opened with exclusive access.  Exclusive opens may
+ * nest for the same @holder.
  *
  * Use this interface 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
@@ -785,10 +785,16 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder,
 		return ERR_PTR(-ENXIO);
 	disk = bdev->bd_disk;
 
-	if (mode & FMODE_EXCL) {
+	if (holder) {
+		mode |= FMODE_EXCL;
 		ret = bd_prepare_to_claim(bdev, holder, hops);
 		if (ret)
 			goto put_blkdev;
+	} else {
+		if (WARN_ON_ONCE(mode & FMODE_EXCL)) {
+			ret = -EIO;
+			goto put_blkdev;
+		}
 	}
 
 	disk_block_events(disk);
@@ -805,7 +811,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder,
 		ret = blkdev_get_whole(bdev, mode);
 	if (ret)
 		goto put_module;
-	if (mode & FMODE_EXCL) {
+	if (holder) {
 		bd_finish_claiming(bdev, holder, hops);
 
 		/*
@@ -829,7 +835,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder,
 put_module:
 	module_put(disk->fops->owner);
 abort_claiming:
-	if (mode & FMODE_EXCL)
+	if (holder)
 		bd_abort_claiming(bdev, holder);
 	mutex_unlock(&disk->open_mutex);
 	disk_unblock_events(disk);
@@ -845,10 +851,9 @@ EXPORT_SYMBOL(blkdev_get_by_dev);
  * @mode: FMODE_* mask
  * @holder: exclusive holder identifier
  *
- * Open the block device described by the device file at @path.  If @mode
- * includes %FMODE_EXCL, the block device is opened with exclusive access.
- * Specifying %FMODE_EXCL with a %NULL @holder is invalid.  Exclusive opens may
- * nest for the same @holder.
+ * Open the block device described by the device file at @path.  If @holder is
+ * not %NULL, the block device is opened with exclusive access.  Exclusive opens
+ * may nest for the same @holder.
  *
  * CONTEXT:
  * Might sleep.
@@ -869,7 +874,7 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 
 	bdev = blkdev_get_by_dev(dev, mode, holder, hops);
 	if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
-		blkdev_put(bdev, mode);
+		blkdev_put(bdev, holder);
 		return ERR_PTR(-EACCES);
 	}
 
@@ -877,7 +882,7 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 }
 EXPORT_SYMBOL(blkdev_get_by_path);
 
-void blkdev_put(struct block_device *bdev, fmode_t mode)
+void blkdev_put(struct block_device *bdev, void *holder)
 {
 	struct gendisk *disk = bdev->bd_disk;
 
@@ -892,8 +897,8 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
 		sync_blockdev(bdev);
 
 	mutex_lock(&disk->open_mutex);
-	if (mode & FMODE_EXCL)
-		bd_end_claim(bdev);
+	if (holder)
+		bd_end_claim(bdev, holder);
 
 	/*
 	 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
diff --git a/block/fops.c b/block/fops.c
index 26af2b39c758..9f26e25bafa1 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -490,7 +490,9 @@ static int blkdev_open(struct inode *inode, struct file *filp)
 	if ((filp->f_flags & O_ACCMODE) == 3)
 		filp->f_mode |= FMODE_WRITE_IOCTL;
 
-	bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp, NULL);
+	bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode,
+				 (filp->f_mode & FMODE_EXCL) ? filp : NULL,
+				 NULL);
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
 
@@ -504,7 +506,7 @@ static int blkdev_release(struct inode *inode, struct file *filp)
 {
 	struct block_device *bdev = filp->private_data;
 
-	blkdev_put(bdev, filp->f_mode);
+	blkdev_put(bdev, (filp->f_mode & FMODE_EXCL) ? filp : NULL);
 	return 0;
 }
 
diff --git a/block/genhd.c b/block/genhd.c
index 4e5fd6aaa883..b56f8b5c88b3 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -365,12 +365,11 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
 	}
 
 	set_bit(GD_NEED_PART_SCAN, &disk->state);
-	bdev = blkdev_get_by_dev(disk_devt(disk), mode & ~FMODE_EXCL, NULL,
-				 NULL);
+	bdev = blkdev_get_by_dev(disk_devt(disk), mode, NULL, NULL);
 	if (IS_ERR(bdev))
 		ret =  PTR_ERR(bdev);
 	else
-		blkdev_put(bdev, mode & ~FMODE_EXCL);
+		blkdev_put(bdev, NULL);
 
 	/*
 	 * If blkdev_get_by_dev() failed early, GD_NEED_PART_SCAN is still set,
diff --git a/block/ioctl.c b/block/ioctl.c
index c7d7d4345edb..b39bd5b41ee4 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -454,11 +454,10 @@ static int blkdev_bszset(struct block_device *bdev, fmode_t mode,
 	if (mode & FMODE_EXCL)
 		return set_blocksize(bdev, n);
 
-	if (IS_ERR(blkdev_get_by_dev(bdev->bd_dev, mode | FMODE_EXCL, &bdev,
-			NULL)))
+	if (IS_ERR(blkdev_get_by_dev(bdev->bd_dev, mode, &bdev, NULL)))
 		return -EBUSY;
 	ret = set_blocksize(bdev, n);
-	blkdev_put(bdev, mode | FMODE_EXCL);
+	blkdev_put(bdev, &bdev);
 
 	return ret;
 }
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index cab59dab3410..10b1e5171332 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1640,8 +1640,7 @@ static struct block_device *open_backing_dev(struct drbd_device *device,
 	struct block_device *bdev;
 	int err = 0;
 
-	bdev = blkdev_get_by_path(bdev_path,
-				  FMODE_READ | FMODE_WRITE | FMODE_EXCL,
+	bdev = blkdev_get_by_path(bdev_path, FMODE_READ | FMODE_WRITE,
 				  claim_ptr, NULL);
 	if (IS_ERR(bdev)) {
 		drbd_err(device, "open(\"%s\") failed with %ld\n",
@@ -1654,7 +1653,7 @@ static struct block_device *open_backing_dev(struct drbd_device *device,
 
 	err = bd_link_disk_holder(bdev, device->vdisk);
 	if (err) {
-		blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+		blkdev_put(bdev, claim_ptr);
 		drbd_err(device, "bd_link_disk_holder(\"%s\", ...) failed with %d\n",
 				bdev_path, err);
 		bdev = ERR_PTR(err);
@@ -1696,13 +1695,13 @@ static int open_backing_devices(struct drbd_device *device,
 }
 
 static void close_backing_dev(struct drbd_device *device, struct block_device *bdev,
-	bool do_bd_unlink)
+		void *claim_ptr, bool do_bd_unlink)
 {
 	if (!bdev)
 		return;
 	if (do_bd_unlink)
 		bd_unlink_disk_holder(bdev, device->vdisk);
-	blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+	blkdev_put(bdev, claim_ptr);
 }
 
 void drbd_backing_dev_free(struct drbd_device *device, struct drbd_backing_dev *ldev)
@@ -1710,8 +1709,11 @@ void drbd_backing_dev_free(struct drbd_device *device, struct drbd_backing_dev *
 	if (ldev == NULL)
 		return;
 
-	close_backing_dev(device, ldev->md_bdev, ldev->md_bdev != ldev->backing_bdev);
-	close_backing_dev(device, ldev->backing_bdev, true);
+	close_backing_dev(device, ldev->md_bdev,
+			  ldev->md.meta_dev_idx < 0 ?
+				(void *)device : (void *)drbd_m_holder,
+			  ldev->md_bdev != ldev->backing_bdev);
+	close_backing_dev(device, ldev->backing_bdev, device, true);
 
 	kfree(ldev->disk_conf);
 	kfree(ldev);
@@ -2127,8 +2129,11 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
  fail:
 	conn_reconfig_done(connection);
 	if (nbc) {
-		close_backing_dev(device, nbc->md_bdev, nbc->md_bdev != nbc->backing_bdev);
-		close_backing_dev(device, nbc->backing_bdev, true);
+		close_backing_dev(device, nbc->md_bdev,
+			  nbc->disk_conf->meta_dev_idx < 0 ?
+				(void *)device : (void *)drbd_m_holder,
+			  nbc->md_bdev != nbc->backing_bdev);
+		close_backing_dev(device, nbc->backing_bdev, device, true);
 		kfree(nbc);
 	}
 	kfree(new_disk_conf);
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 7bfc058cb665..c3299e49edd5 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2167,8 +2167,7 @@ static int pkt_open_dev(struct pktcdvd_device *pd, fmode_t write)
 	 * to read/write from/to it. It is already opened in O_NONBLOCK mode
 	 * so open should not fail.
 	 */
-	bdev = blkdev_get_by_dev(pd->bdev->bd_dev, FMODE_READ | FMODE_EXCL, pd,
-				 NULL);
+	bdev = blkdev_get_by_dev(pd->bdev->bd_dev, FMODE_READ, pd, NULL);
 	if (IS_ERR(bdev)) {
 		ret = PTR_ERR(bdev);
 		goto out;
@@ -2215,7 +2214,7 @@ static int pkt_open_dev(struct pktcdvd_device *pd, fmode_t write)
 	return 0;
 
 out_putdev:
-	blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
+	blkdev_put(bdev, pd);
 out:
 	return ret;
 }
@@ -2234,7 +2233,7 @@ static void pkt_release_dev(struct pktcdvd_device *pd, int flush)
 	pkt_lock_door(pd, 0);
 
 	pkt_set_speed(pd, MAX_SPEED, MAX_SPEED);
-	blkdev_put(pd->bdev, FMODE_READ | FMODE_EXCL);
+	blkdev_put(pd->bdev, pd);
 
 	pkt_shrink_pktlist(pd);
 }
@@ -2520,7 +2519,7 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
 		return PTR_ERR(bdev);
 	sdev = scsi_device_from_queue(bdev->bd_disk->queue);
 	if (!sdev) {
-		blkdev_put(bdev, FMODE_READ | FMODE_NDELAY);
+		blkdev_put(bdev, NULL);
 		return -EINVAL;
 	}
 	put_device(&sdev->sdev_gendev);
@@ -2545,7 +2544,7 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
 	return 0;
 
 out_mem:
-	blkdev_put(bdev, FMODE_READ | FMODE_NDELAY);
+	blkdev_put(bdev, NULL);
 	/* This is safe: open() is still holding a reference. */
 	module_put(THIS_MODULE);
 	return -ENOMEM;
@@ -2751,7 +2750,7 @@ static int pkt_remove_dev(dev_t pkt_dev)
 	pkt_debugfs_dev_remove(pd);
 	pkt_sysfs_dev_remove(pd);
 
-	blkdev_put(pd->bdev, FMODE_READ | FMODE_NDELAY);
+	blkdev_put(pd->bdev, NULL);
 
 	remove_proc_entry(pd->disk->disk_name, pkt_proc);
 	dev_notice(ddev, "writer unmapped\n");
diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
index a92a4289d0ec..a909f8763ce7 100644
--- a/drivers/block/rnbd/rnbd-srv.c
+++ b/drivers/block/rnbd/rnbd-srv.c
@@ -219,7 +219,7 @@ void rnbd_destroy_sess_dev(struct rnbd_srv_sess_dev *sess_dev, bool keep_id)
 	rnbd_put_sess_dev(sess_dev);
 	wait_for_completion(&dc); /* wait for inflights to drop to zero */
 
-	blkdev_put(sess_dev->bdev, sess_dev->open_flags);
+	blkdev_put(sess_dev->bdev, NULL);
 	mutex_lock(&sess_dev->dev->lock);
 	list_del(&sess_dev->dev_list);
 	if (sess_dev->open_flags & FMODE_WRITE)
@@ -791,7 +791,7 @@ srv_dev_put:
 	}
 	rnbd_put_srv_dev(srv_dev);
 blkdev_put:
-	blkdev_put(bdev, open_flags);
+	blkdev_put(bdev, NULL);
 free_path:
 	kfree(full_path);
 reject:
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 43b36da9b354..141b60aad570 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -473,7 +473,7 @@ static void xenvbd_sysfs_delif(struct xenbus_device *dev)
 static void xen_vbd_free(struct xen_vbd *vbd)
 {
 	if (vbd->bdev)
-		blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE);
+		blkdev_put(vbd->bdev, NULL);
 	vbd->bdev = NULL;
 }
 
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index f5644c606040..21615d67a9bd 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -420,7 +420,7 @@ static void reset_bdev(struct zram *zram)
 		return;
 
 	bdev = zram->bdev;
-	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
+	blkdev_put(bdev, zram);
 	/* hope filp_close flush all of IO */
 	filp_close(zram->backing_dev, NULL);
 	zram->backing_dev = NULL;
@@ -507,8 +507,8 @@ static ssize_t backing_dev_store(struct device *dev,
 		goto out;
 	}
 
-	bdev = blkdev_get_by_dev(inode->i_rdev,
-			FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram, NULL);
+	bdev = blkdev_get_by_dev(inode->i_rdev, FMODE_READ | FMODE_WRITE, zram,
+				 NULL);
 	if (IS_ERR(bdev)) {
 		err = PTR_ERR(bdev);
 		bdev = NULL;
@@ -539,7 +539,7 @@ out:
 	kvfree(bitmap);
 
 	if (bdev)
-		blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+		blkdev_put(bdev, zram);
 
 	if (backing_dev)
 		filp_close(backing_dev, NULL);
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 4a2aed047aec..7022fea396f2 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1369,7 +1369,7 @@ static void cached_dev_free(struct closure *cl)
 		put_page(virt_to_page(dc->sb_disk));
 
 	if (!IS_ERR_OR_NULL(dc->bdev))
-		blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
+		blkdev_put(dc->bdev, bcache_kobj);
 
 	wake_up(&unregister_wait);
 
@@ -2218,7 +2218,7 @@ void bch_cache_release(struct kobject *kobj)
 		put_page(virt_to_page(ca->sb_disk));
 
 	if (!IS_ERR_OR_NULL(ca->bdev))
-		blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
+		blkdev_put(ca->bdev, bcache_kobj);
 
 	kfree(ca);
 	module_put(THIS_MODULE);
@@ -2359,7 +2359,7 @@ static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
 		 * call blkdev_put() to bdev in bch_cache_release(). So we
 		 * explicitly call blkdev_put() here.
 		 */
-		blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
+		blkdev_put(bdev, bcache_kobj);
 		if (ret == -ENOMEM)
 			err = "cache_alloc(): -ENOMEM";
 		else if (ret == -EPERM)
@@ -2461,7 +2461,7 @@ static void register_bdev_worker(struct work_struct *work)
 	if (!dc) {
 		fail = true;
 		put_page(virt_to_page(args->sb_disk));
-		blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+		blkdev_put(args->bdev, bcache_kobj);
 		goto out;
 	}
 
@@ -2491,7 +2491,7 @@ static void register_cache_worker(struct work_struct *work)
 	if (!ca) {
 		fail = true;
 		put_page(virt_to_page(args->sb_disk));
-		blkdev_put(args->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+		blkdev_put(args->bdev, bcache_kobj);
 		goto out;
 	}
 
@@ -2558,8 +2558,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 
 	ret = -EINVAL;
 	err = "failed to open device";
-	bdev = blkdev_get_by_path(strim(path),
-				  FMODE_READ|FMODE_WRITE|FMODE_EXCL,
+	bdev = blkdev_get_by_path(strim(path), FMODE_READ | FMODE_WRITE,
 				  bcache_kobj, NULL);
 	if (IS_ERR(bdev)) {
 		if (bdev == ERR_PTR(-EBUSY)) {
@@ -2648,7 +2647,7 @@ async_done:
 out_put_sb_page:
 	put_page(virt_to_page(sb_disk));
 out_blkdev_put:
-	blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+	blkdev_put(bdev, register_bcache);
 out_free_sb:
 	kfree(sb);
 out_free_path:
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 246b8f028a98..b16e37362c5a 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -746,7 +746,7 @@ static struct table_device *open_table_device(struct mapped_device *md,
 		return ERR_PTR(-ENOMEM);
 	refcount_set(&td->count, 1);
 
-	bdev = blkdev_get_by_dev(dev, mode | FMODE_EXCL, _dm_claim_ptr, NULL);
+	bdev = blkdev_get_by_dev(dev, mode, _dm_claim_ptr, NULL);
 	if (IS_ERR(bdev)) {
 		r = PTR_ERR(bdev);
 		goto out_free_td;
@@ -771,7 +771,7 @@ static struct table_device *open_table_device(struct mapped_device *md,
 	return td;
 
 out_blkdev_put:
-	blkdev_put(bdev, mode | FMODE_EXCL);
+	blkdev_put(bdev, _dm_claim_ptr);
 out_free_td:
 	kfree(td);
 	return ERR_PTR(r);
@@ -784,7 +784,7 @@ static void close_table_device(struct table_device *td, struct mapped_device *md
 {
 	if (md->disk->slave_dir)
 		bd_unlink_disk_holder(td->dm_dev.bdev, md->disk);
-	blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
+	blkdev_put(td->dm_dev.bdev, _dm_claim_ptr);
 	put_dax(td->dm_dev.dax_dev);
 	list_del(&td->list);
 	kfree(td);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 159197dd7b6d..dad4a5539f9f 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2449,7 +2449,10 @@ static void rdev_delayed_delete(struct work_struct *ws)
 
 void md_autodetect_dev(dev_t dev);
 
-static void export_rdev(struct md_rdev *rdev)
+/* just for claiming the bdev */
+static struct md_rdev claim_rdev;
+
+static void export_rdev(struct md_rdev *rdev, struct mddev *mddev)
 {
 	pr_debug("md: export_rdev(%pg)\n", rdev->bdev);
 	md_rdev_clear(rdev);
@@ -2457,7 +2460,7 @@ static void export_rdev(struct md_rdev *rdev)
 	if (test_bit(AutoDetected, &rdev->flags))
 		md_autodetect_dev(rdev->bdev->bd_dev);
 #endif
-	blkdev_put(rdev->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+	blkdev_put(rdev->bdev, mddev->major_version == -2 ? &claim_rdev : rdev);
 	rdev->bdev = NULL;
 	kobject_put(&rdev->kobj);
 }
@@ -2485,7 +2488,7 @@ static void md_kick_rdev_from_array(struct md_rdev *rdev)
 	INIT_WORK(&rdev->del_work, rdev_delayed_delete);
 	kobject_get(&rdev->kobj);
 	queue_work(md_rdev_misc_wq, &rdev->del_work);
-	export_rdev(rdev);
+	export_rdev(rdev, rdev->mddev);
 }
 
 static void export_array(struct mddev *mddev)
@@ -3612,6 +3615,7 @@ int md_rdev_init(struct md_rdev *rdev)
 	return badblocks_init(&rdev->badblocks, 0);
 }
 EXPORT_SYMBOL_GPL(md_rdev_init);
+
 /*
  * Import a device. If 'super_format' >= 0, then sanity check the superblock
  *
@@ -3624,7 +3628,6 @@ EXPORT_SYMBOL_GPL(md_rdev_init);
  */
 static struct md_rdev *md_import_device(dev_t newdev, int super_format, int super_minor)
 {
-	static struct md_rdev claim_rdev; /* just for claiming the bdev */
 	struct md_rdev *rdev;
 	sector_t size;
 	int err;
@@ -3640,8 +3643,7 @@ static struct md_rdev *md_import_device(dev_t newdev, int super_format, int supe
 	if (err)
 		goto out_clear_rdev;
 
-	rdev->bdev = blkdev_get_by_dev(newdev,
-			FMODE_READ | FMODE_WRITE | FMODE_EXCL,
+	rdev->bdev = blkdev_get_by_dev(newdev, FMODE_READ | FMODE_WRITE,
 			super_format == -2 ? &claim_rdev : rdev, NULL);
 	if (IS_ERR(rdev->bdev)) {
 		pr_warn("md: could not open device unknown-block(%u,%u).\n",
@@ -3679,7 +3681,7 @@ static struct md_rdev *md_import_device(dev_t newdev, int super_format, int supe
 	return rdev;
 
 out_blkdev_put:
-	blkdev_put(rdev->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+	blkdev_put(rdev->bdev, super_format == -2 ? &claim_rdev : rdev);
 out_clear_rdev:
 	md_rdev_clear(rdev);
 out_free_rdev:
@@ -4560,7 +4562,7 @@ new_dev_store(struct mddev *mddev, const char *buf, size_t len)
 	err = bind_rdev_to_array(rdev, mddev);
  out:
 	if (err)
-		export_rdev(rdev);
+		export_rdev(rdev, mddev);
 	mddev_unlock(mddev);
 	if (!err)
 		md_new_event();
@@ -6498,7 +6500,7 @@ static void autorun_devices(int part)
 			rdev_for_each_list(rdev, tmp, &candidates) {
 				list_del_init(&rdev->same_set);
 				if (bind_rdev_to_array(rdev, mddev))
-					export_rdev(rdev);
+					export_rdev(rdev, mddev);
 			}
 			autorun_array(mddev);
 			mddev_unlock(mddev);
@@ -6508,7 +6510,7 @@ static void autorun_devices(int part)
 		 */
 		rdev_for_each_list(rdev, tmp, &candidates) {
 			list_del_init(&rdev->same_set);
-			export_rdev(rdev);
+			export_rdev(rdev, mddev);
 		}
 		mddev_put(mddev);
 	}
@@ -6696,13 +6698,13 @@ int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info)
 				pr_warn("md: %pg has different UUID to %pg\n",
 					rdev->bdev,
 					rdev0->bdev);
-				export_rdev(rdev);
+				export_rdev(rdev, mddev);
 				return -EINVAL;
 			}
 		}
 		err = bind_rdev_to_array(rdev, mddev);
 		if (err)
-			export_rdev(rdev);
+			export_rdev(rdev, mddev);
 		return err;
 	}
 
@@ -6746,7 +6748,7 @@ int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info)
 			/* This was a hot-add request, but events doesn't
 			 * match, so reject it.
 			 */
-			export_rdev(rdev);
+			export_rdev(rdev, mddev);
 			return -EINVAL;
 		}
 
@@ -6772,7 +6774,7 @@ int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info)
 				}
 			}
 			if (has_journal || mddev->bitmap) {
-				export_rdev(rdev);
+				export_rdev(rdev, mddev);
 				return -EBUSY;
 			}
 			set_bit(Journal, &rdev->flags);
@@ -6787,7 +6789,7 @@ int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info)
 				/* --add initiated by this node */
 				err = md_cluster_ops->add_new_disk(mddev, rdev);
 				if (err) {
-					export_rdev(rdev);
+					export_rdev(rdev, mddev);
 					return err;
 				}
 			}
@@ -6797,7 +6799,7 @@ int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info)
 		err = bind_rdev_to_array(rdev, mddev);
 
 		if (err)
-			export_rdev(rdev);
+			export_rdev(rdev, mddev);
 
 		if (mddev_is_clustered(mddev)) {
 			if (info->state & (1 << MD_DISK_CANDIDATE)) {
@@ -6860,7 +6862,7 @@ int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info)
 
 		err = bind_rdev_to_array(rdev, mddev);
 		if (err) {
-			export_rdev(rdev);
+			export_rdev(rdev, mddev);
 			return err;
 		}
 	}
@@ -6985,7 +6987,7 @@ static int hot_add_disk(struct mddev *mddev, dev_t dev)
 	return 0;
 
 abort_export:
-	export_rdev(rdev);
+	export_rdev(rdev, mddev);
 	return err;
 }
 
diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index 218eb2af564a..44fc23af4c3f 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -209,7 +209,7 @@ static void block2mtd_free_device(struct block2mtd_dev *dev)
 	if (dev->blkdev) {
 		invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping,
 					0, -1);
-		blkdev_put(dev->blkdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
+		blkdev_put(dev->blkdev, NULL);
 	}
 
 	kfree(dev);
@@ -261,7 +261,7 @@ static struct block_device __ref *mdtblock_early_get_bdev(const char *devname,
 static struct block2mtd_dev *add_device(char *devname, int erase_size,
 		char *label, int timeout)
 {
-	const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
+	const fmode_t mode = FMODE_READ | FMODE_WRITE;
 	struct block_device *bdev;
 	struct block2mtd_dev *dev;
 	char *name;
diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
index 9b6d6d85c725..65ed2d478fac 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -51,7 +51,7 @@ void nvmet_bdev_set_limits(struct block_device *bdev, struct nvme_id_ns *id)
 void nvmet_bdev_ns_disable(struct nvmet_ns *ns)
 {
 	if (ns->bdev) {
-		blkdev_put(ns->bdev, FMODE_WRITE | FMODE_READ);
+		blkdev_put(ns->bdev, NULL);
 		ns->bdev = NULL;
 	}
 }
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index f21198bc483e..d2b27b84f854 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -179,7 +179,7 @@ void dasd_destroy_partitions(struct dasd_block *block)
 	mutex_unlock(&bdev->bd_disk->open_mutex);
 
 	/* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
-	blkdev_put(bdev, FMODE_READ);
+	blkdev_put(bdev, NULL);
 }
 
 int dasd_gendisk_init(void)
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index a5cbbefa78ee..c62f961f46e3 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -108,7 +108,7 @@ static int iblock_configure_device(struct se_device *dev)
 	pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
 			ib_dev->ibd_udev_path);
 
-	mode = FMODE_READ|FMODE_EXCL;
+	mode = FMODE_READ;
 	if (!ib_dev->ibd_readonly)
 		mode |= FMODE_WRITE;
 	else
@@ -175,7 +175,7 @@ static int iblock_configure_device(struct se_device *dev)
 	return 0;
 
 out_blkdev_put:
-	blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
+	blkdev_put(ib_dev->ibd_bd, ib_dev);
 out_free_bioset:
 	bioset_exit(&ib_dev->ibd_bio_set);
 out:
@@ -201,7 +201,7 @@ static void iblock_destroy_device(struct se_device *dev)
 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 
 	if (ib_dev->ibd_bd != NULL)
-		blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
+