block: introduce holder ops

Add a new blk_holder_ops structure, which is passed to blkdev_get_by_* and
installed in the block_device for exclusive claims.  It will be used to
allow the block layer to call back into the user of the block device for
thing like notification of a removed device or a device resize.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

34 files changed, 90 insertions, 56 deletions

diff --git a/block/bdev.c b/block/bdev.c
index f5ffcac762e0..5c46ff107706 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -102,7 +102,7 @@ int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
 	 * under live filesystem.
 	 */
 	if (!(mode & FMODE_EXCL)) {
-		int err = bd_prepare_to_claim(bdev, truncate_bdev_range);
+		int err = bd_prepare_to_claim(bdev, truncate_bdev_range, NULL);
 		if (err)
 			goto invalidate;
 	}
@@ -415,6 +415,7 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 	bdev = I_BDEV(inode);
 	mutex_init(&bdev->bd_fsfreeze_mutex);
 	spin_lock_init(&bdev->bd_size_lock);
+	mutex_init(&bdev->bd_holder_lock);
 	bdev->bd_partno = partno;
 	bdev->bd_inode = inode;
 	bdev->bd_queue = disk->queue;
@@ -464,13 +465,15 @@ long nr_blockdev_pages(void)
  * bd_may_claim - test whether a block device can be claimed
  * @bdev: block device of interest
  * @holder: holder trying to claim @bdev
+ * @hops: holder ops
  *
  * Test whether @bdev can be claimed by @holder.
  *
  * RETURNS:
  * %true if @bdev can be claimed, %false otherwise.
  */
-static bool bd_may_claim(struct block_device *bdev, void *holder)
+static bool bd_may_claim(struct block_device *bdev, void *holder,
+		const struct blk_holder_ops *hops)
 {
 	struct block_device *whole = bdev_whole(bdev);
 
@@ -480,8 +483,11 @@ static bool bd_may_claim(struct block_device *bdev, void *holder)
 		/*
 		 * The same holder can always re-claim.
 		 */
-		if (bdev->bd_holder == holder)
+		if (bdev->bd_holder == holder) {
+			if (WARN_ON_ONCE(bdev->bd_holder_ops != hops))
+				return false;
 			return true;
+		}
 		return false;
 	}
 
@@ -499,6 +505,7 @@ static bool bd_may_claim(struct block_device *bdev, void *holder)
  * bd_prepare_to_claim - claim a block device
  * @bdev: block device of interest
  * @holder: holder trying to claim @bdev
+ * @hops: holder ops.
  *
  * Claim @bdev.  This function fails if @bdev is already claimed by another
  * holder and waits if another claiming is in progress. return, the caller
@@ -507,7 +514,8 @@ static bool bd_may_claim(struct block_device *bdev, void *holder)
  * RETURNS:
  * 0 if @bdev can be claimed, -EBUSY otherwise.
  */
-int bd_prepare_to_claim(struct block_device *bdev, void *holder)
+int bd_prepare_to_claim(struct block_device *bdev, void *holder,
+		const struct blk_holder_ops *hops)
 {
 	struct block_device *whole = bdev_whole(bdev);
 
@@ -516,7 +524,7 @@ int bd_prepare_to_claim(struct block_device *bdev, void *holder)
 retry:
 	mutex_lock(&bdev_lock);
 	/* if someone else claimed, fail */
-	if (!bd_may_claim(bdev, holder)) {
+	if (!bd_may_claim(bdev, holder, hops)) {
 		mutex_unlock(&bdev_lock);
 		return -EBUSY;
 	}
@@ -557,12 +565,13 @@ static void bd_clear_claiming(struct block_device *whole, void *holder)
  * Finish exclusive open of a block device. Mark the device as exlusively
  * open by the holder and wake up all waiters for exclusive open to finish.
  */
-static void bd_finish_claiming(struct block_device *bdev, void *holder)
+static void bd_finish_claiming(struct block_device *bdev, void *holder,
+		const struct blk_holder_ops *hops)
 {
 	struct block_device *whole = bdev_whole(bdev);
 
 	mutex_lock(&bdev_lock);
-	BUG_ON(!bd_may_claim(bdev, holder));
+	BUG_ON(!bd_may_claim(bdev, holder, hops));
 	/*
 	 * 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
@@ -570,7 +579,10 @@ static void bd_finish_claiming(struct block_device *bdev, void *holder)
 	whole->bd_holders++;
 	whole->bd_holder = bd_may_claim;
 	bdev->bd_holders++;
+	mutex_lock(&bdev->bd_holder_lock);
 	bdev->bd_holder = holder;
+	bdev->bd_holder_ops = hops;
+	mutex_unlock(&bdev->bd_holder_lock);
 	bd_clear_claiming(whole, holder);
 	mutex_unlock(&bdev_lock);
 }
@@ -605,7 +617,10 @@ static void bd_end_claim(struct block_device *bdev)
 	WARN_ON_ONCE(--bdev->bd_holders < 0);
 	WARN_ON_ONCE(--whole->bd_holders < 0);
 	if (!bdev->bd_holders) {
+		mutex_lock(&bdev->bd_holder_lock);
 		bdev->bd_holder = NULL;
+		bdev->bd_holder_ops = NULL;
+		mutex_unlock(&bdev->bd_holder_lock);
 		if (bdev->bd_write_holder)
 			unblock = true;
 	}
@@ -735,6 +750,7 @@ void blkdev_put_no_open(struct block_device *bdev)
  * @dev: device number of block device to open
  * @mode: FMODE_* mask
  * @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
@@ -751,7 +767,8 @@ void blkdev_put_no_open(struct block_device *bdev)
  * RETURNS:
  * Reference to the 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 *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder,
+		const struct blk_holder_ops *hops)
 {
 	bool unblock_events = true;
 	struct block_device *bdev;
@@ -771,7 +788,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 	disk = bdev->bd_disk;
 
 	if (mode & FMODE_EXCL) {
-		ret = bd_prepare_to_claim(bdev, holder);
+		ret = bd_prepare_to_claim(bdev, holder, hops);
 		if (ret)
 			goto put_blkdev;
 	}
@@ -791,7 +808,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 	if (ret)
 		goto put_module;
 	if (mode & FMODE_EXCL) {
-		bd_finish_claiming(bdev, holder);
+		bd_finish_claiming(bdev, holder, hops);
 
 		/*
 		 * Block event polling for write claims if requested.  Any write
@@ -842,7 +859,7 @@ EXPORT_SYMBOL(blkdev_get_by_dev);
  * Reference to the block_device on success, ERR_PTR(-errno) on failure.
  */
 struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
-					void *holder)
+		void *holder, const struct blk_holder_ops *hops)
 {
 	struct block_device *bdev;
 	dev_t dev;
@@ -852,7 +869,7 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 	if (error)
 		return ERR_PTR(error);
 
-	bdev = blkdev_get_by_dev(dev, mode, holder);
+	bdev = blkdev_get_by_dev(dev, mode, holder, hops);
 	if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
 		blkdev_put(bdev, mode);
 		return ERR_PTR(-EACCES);
diff --git a/block/fops.c b/block/fops.c
index b12c4b2a3a69..6a3087b750a6 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -490,7 +490,7 @@ 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);
+	bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp, NULL);
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
 
diff --git a/block/genhd.c b/block/genhd.c
index a668d2f02087..b3bd58e9fbea 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -370,13 +370,15 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
 	 * scanners.
 	 */
 	if (!(mode & FMODE_EXCL)) {
-		ret = bd_prepare_to_claim(disk->part0, disk_scan_partitions);
+		ret = bd_prepare_to_claim(disk->part0, disk_scan_partitions,
+					  NULL);
 		if (ret)
 			return ret;
 	}
 
 	set_bit(GD_NEED_PART_SCAN, &disk->state);
-	bdev = blkdev_get_by_dev(disk_devt(disk), mode & ~FMODE_EXCL, NULL);
+	bdev = blkdev_get_by_dev(disk_devt(disk), mode & ~FMODE_EXCL, NULL,
+				 NULL);
 	if (IS_ERR(bdev))
 		ret =  PTR_ERR(bdev);
 	else
diff --git a/block/ioctl.c b/block/ioctl.c
index 9c5f637ff153..c7d7d4345edb 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -454,7 +454,8 @@ 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)))
+	if (IS_ERR(blkdev_get_by_dev(bdev->bd_dev, mode | FMODE_EXCL, &bdev,
+			NULL)))
 		return -EBUSY;
 	ret = set_blocksize(bdev, n);
 	blkdev_put(bdev, mode | FMODE_EXCL);
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 1a5d3d72d91d..cab59dab3410 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1641,7 +1641,8 @@ static struct block_device *open_backing_dev(struct drbd_device *device,
 	int err = 0;
 
 	bdev = blkdev_get_by_path(bdev_path,
-				  FMODE_READ | FMODE_WRITE | FMODE_EXCL, claim_ptr);
+				  FMODE_READ | FMODE_WRITE | FMODE_EXCL,
+				  claim_ptr, NULL);
 	if (IS_ERR(bdev)) {
 		drbd_err(device, "open(\"%s\") failed with %ld\n",
 				bdev_path, PTR_ERR(bdev));
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index bc31bb7072a2..a73c857f5bfe 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1015,7 +1015,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 	 * here to avoid changing device under exclusive owner.
 	 */
 	if (!(mode & FMODE_EXCL)) {
-		error = bd_prepare_to_claim(bdev, loop_configure);
+		error = bd_prepare_to_claim(bdev, loop_configure, NULL);
 		if (error)
 			goto out_putf;
 	}
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index d5d7884cedd4..377f8b345352 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2125,7 +2125,8 @@ 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);
+	bdev = blkdev_get_by_dev(pd->bdev->bd_dev, FMODE_READ | FMODE_EXCL, pd,
+				 NULL);
 	if (IS_ERR(bdev)) {
 		ret = PTR_ERR(bdev);
 		goto out;
@@ -2530,7 +2531,7 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
 		}
 	}
 
-	bdev = blkdev_get_by_dev(dev, FMODE_READ | FMODE_NDELAY, NULL);
+	bdev = blkdev_get_by_dev(dev, FMODE_READ | FMODE_NDELAY, NULL, NULL);
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
 	sdev = scsi_device_from_queue(bdev->bd_disk->queue);
diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
index 2cfed2e58d64..cec22bbae2f9 100644
--- a/drivers/block/rnbd/rnbd-srv.c
+++ b/drivers/block/rnbd/rnbd-srv.c
@@ -719,7 +719,7 @@ static int process_msg_open(struct rnbd_srv_session *srv_sess,
 		goto reject;
 	}
 
-	bdev = blkdev_get_by_path(full_path, open_flags, THIS_MODULE);
+	bdev = blkdev_get_by_path(full_path, open_flags, THIS_MODULE, NULL);
 	if (IS_ERR(bdev)) {
 		ret = PTR_ERR(bdev);
 		pr_err("Opening device '%s' on session %s failed, failed to open the block device, err: %d\n",
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 4807af1d5805..43b36da9b354 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -492,7 +492,7 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
 	vbd->pdevice  = MKDEV(major, minor);
 
 	bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ?
-				 FMODE_READ : FMODE_WRITE, NULL);
+				 FMODE_READ : FMODE_WRITE, NULL, NULL);
 
 	if (IS_ERR(bdev)) {
 		pr_warn("xen_vbd_create: device %08x could not be opened\n",
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index b86691d2133e..0bc779446c6f 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -508,7 +508,7 @@ static ssize_t backing_dev_store(struct device *dev,
 	}
 
 	bdev = blkdev_get_by_dev(inode->i_rdev,
-			FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram);
+			FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram, NULL);
 	if (IS_ERR(bdev)) {
 		err = PTR_ERR(bdev);
 		bdev = NULL;
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 7e9d19fd21dd..d84c09a73af8 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2560,7 +2560,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 	err = "failed to open device";
 	bdev = blkdev_get_by_path(strim(path),
 				  FMODE_READ|FMODE_WRITE|FMODE_EXCL,
-				  sb);
+				  sb, NULL);
 	if (IS_ERR(bdev)) {
 		if (bdev == ERR_PTR(-EBUSY)) {
 			dev_t dev;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3b694ba3a106..d759f8bdb3df 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);
+	bdev = blkdev_get_by_dev(dev, mode | FMODE_EXCL, _dm_claim_ptr, NULL);
 	if (IS_ERR(bdev)) {
 		r = PTR_ERR(bdev);
 		goto out_free_td;
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 6a559a7e89c0..fabf9c543735 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3642,7 +3642,7 @@ static struct md_rdev *md_import_device(dev_t newdev, int super_format, int supe
 
 	rdev->bdev = blkdev_get_by_dev(newdev,
 			FMODE_READ | FMODE_WRITE | FMODE_EXCL,
-			super_format == -2 ? &claim_rdev : rdev);
+			super_format == -2 ? &claim_rdev : rdev, NULL);
 	if (IS_ERR(rdev->bdev)) {
 		pr_warn("md: could not open device unknown-block(%u,%u).\n",
 			MAJOR(newdev), MINOR(newdev));
diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index 4cd37ec45762..7ac82c6fe350 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -235,7 +235,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size,
 		return NULL;
 
 	/* Get a handle on the device */
-	bdev = blkdev_get_by_path(devname, mode, dev);
+	bdev = blkdev_get_by_path(devname, mode, dev, NULL);
 
 #ifndef MODULE
 	/*
@@ -257,7 +257,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size,
 		devt = name_to_dev_t(devname);
 		if (!devt)
 			continue;
-		bdev = blkdev_get_by_dev(devt, mode, dev);
+		bdev = blkdev_get_by_dev(devt, mode, dev, NULL);
 	}
 #endif
 
diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
index c2d6cea0236b..9b6d6d85c725 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -85,7 +85,7 @@ int nvmet_bdev_ns_enable(struct nvmet_ns *ns)
 		return -ENOTBLK;
 
 	ns->bdev = blkdev_get_by_path(ns->device_path,
-			FMODE_READ | FMODE_WRITE, NULL);
+			FMODE_READ | FMODE_WRITE, NULL, NULL);
 	if (IS_ERR(ns->bdev)) {
 		ret = PTR_ERR(ns->bdev);
 		if (ret != -ENOTBLK) {
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 998a961e1704..f21198bc483e 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -130,7 +130,7 @@ int dasd_scan_partitions(struct dasd_block *block)
 	struct block_device *bdev;
 	int rc;
 
-	bdev = blkdev_get_by_dev(disk_devt(block->gdp), FMODE_READ, NULL);
+	bdev = blkdev_get_by_dev(disk_devt(block->gdp), FMODE_READ, NULL, NULL);
 	if (IS_ERR(bdev)) {
 		DBF_DEV_EVENT(DBF_ERR, block->base,
 			      "scan partitions error, blkdev_get returned %ld",
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index cc838ffd1294..a5cbbefa78ee 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -114,7 +114,7 @@ static int iblock_configure_device(struct se_device *dev)
 	else
 		dev->dev_flags |= DF_READ_ONLY;
 
-	bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
+	bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev, NULL);
 	if (IS_ERR(bd)) {
 		ret = PTR_ERR(bd);
 		goto out_free_bioset;
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index e7425549e39c..e3494e036c6c 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -367,7 +367,8 @@ static int pscsi_create_type_disk(struct se_device *dev, struct scsi_device *sd)
 	 * for TYPE_DISK and TYPE_ZBC using supplied udev_path
 	 */
 	bd = blkdev_get_by_path(dev->udev_path,
-				FMODE_WRITE|FMODE_READ|FMODE_EXCL, pdv);
+				FMODE_WRITE|FMODE_READ|FMODE_EXCL, pdv,
+				NULL);
 	if (IS_ERR(bd)) {
 		pr_err("pSCSI: blkdev_get_by_path() failed\n");
 		scsi_device_put(sd);
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 78696d331639..4de4984fa99b 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -258,7 +258,7 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 	}
 
 	bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
-				  fs_info->bdev_holder);
+				  fs_info->bdev_holder, NULL);
 	if (IS_ERR(bdev)) {
 		btrfs_err(fs_info, "target device %s is invalid!", device_path);
 		return PTR_ERR(bdev);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 841e799dece5..784ccc8f6c69 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -496,7 +496,7 @@ btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 {
 	int ret;
 
-	*bdev = blkdev_get_by_path(device_path, flags, holder);
+	*bdev = blkdev_get_by_path(device_path, flags, holder, NULL);
 
 	if (IS_ERR(*bdev)) {
 		ret = PTR_ERR(*bdev);
@@ -1377,7 +1377,7 @@ struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags,
 	 * values temporarily, as the device paths of the fsid are the only
 	 * required information for assembling the volume.
 	 */
-	bdev = blkdev_get_by_path(path, flags, holder);
+	bdev = blkdev_get_by_path(path, flags, holder, NULL);
 	if (IS_ERR(bdev))
 		return ERR_CAST(bdev);
 
@@ -2629,7 +2629,7 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
 		return -EROFS;
 
 	bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
-				  fs_info->bdev_holder);
+				  fs_info->bdev_holder, NULL);
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
 
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 811ab66d805e..6c263e9cd38b 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -254,7 +254,7 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
 		dif->fscache = fscache;
 	} else if (!sbi->devs->flatdev) {
 		bdev = blkdev_get_by_path(dif->path, FMODE_READ | FMODE_EXCL,
-					  sb->s_type);
+					  sb->s_type, NULL);
 		if (IS_ERR(bdev))
 			return PTR_ERR(bdev);
 		dif->bdev = bdev;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9680fe753e59..865625089ecc 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1103,7 +1103,8 @@ static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
 {
 	struct block_device *bdev;
 
-	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
+	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb,
+				 NULL);
 	if (IS_ERR(bdev))
 		goto fail;
 	return bdev;
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 9f15b03037db..7c34ab082f13 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4025,7 +4025,7 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
 			/* Single zoned block device mount */
 			FDEV(0).bdev =
 				blkdev_get_by_dev(sbi->sb->s_bdev->bd_dev,
-					sbi->sb->s_mode, sbi->sb->s_type);
+					sbi->sb->s_mode, sbi->sb->s_type, NULL);
 		} else {
 			/* Multi-device mount */
 			memcpy(FDEV(i).path, RDEV(i).path, MAX_PATH_LEN);
@@ -4044,7 +4044,7 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
 					sbi->log_blocks_per_seg) - 1;
 			}
 			FDEV(i).bdev = blkdev_get_by_path(FDEV(i).path,
-					sbi->sb->s_mode, sbi->sb->s_type);
+					sbi->sb->s_mode, sbi->sb->s_type, NULL);
 		}
 		if (IS_ERR(FDEV(i).bdev))
 			return PTR_ERR(FDEV(i).bdev);
diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 15c645827dec..46d393c8088a 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1101,7 +1101,7 @@ int lmLogOpen(struct super_block *sb)
 	 */
 
 	bdev = blkdev_get_by_dev(sbi->logdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
-				 log);
+				 log, NULL);
 	if (IS_ERR(bdev)) {
 		rc = PTR_ERR(bdev);
 		goto free;
diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c
index fea5f8821da5..38b066ca699e 100644
--- a/fs/nfs/blocklayout/dev.c
+++ b/fs/nfs/blocklayout/dev.c
@@ -243,7 +243,7 @@ bl_parse_simple(struct nfs_server *server, struct pnfs_block_dev *d,
 	if (!dev)
 		return -EIO;
 
-	bdev = blkdev_get_by_dev(dev, FMODE_READ | FMODE_WRITE, NULL);
+	bdev = blkdev_get_by_dev(dev, FMODE_READ | FMODE_WRITE, NULL, NULL);
 	if (IS_ERR(bdev)) {
 		printk(KERN_WARNING "pNFS: failed to open device %d:%d (%ld)\n",
 			MAJOR(dev), MINOR(dev), PTR_ERR(bdev));
@@ -312,7 +312,8 @@ bl_open_path(struct pnfs_block_volume *v, const char *prefix)
 	if (!devname)
 		return ERR_PTR(-ENOMEM);
 
-	bdev = blkdev_get_by_path(devname, FMODE_READ | FMODE_WRITE, NULL);
+	bdev = blkdev_get_by_path(devname, FMODE_READ | FMODE_WRITE, NULL,
+				  NULL);
 	if (IS_ERR(bdev)) {
 		pr_warn("pNFS: failed to open device %s (%ld)\n",
 			devname, PTR_ERR(bdev));
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 77f1e5778d1c..91bfbd973d1d 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -1285,7 +1285,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
 	if (!(flags & SB_RDONLY))
 		mode |= FMODE_WRITE;
 
-	sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
+	sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type, NULL);
 	if (IS_ERR(sd.bdev))
 		return ERR_CAST(sd.bdev);
 
diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 60b97c92e2b2..6b13b8c3f2b8 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -1786,7 +1786,7 @@ static ssize_t o2hb_region_dev_store(struct config_item *item,
 		goto out2;
 
 	reg->hr_bdev = blkdev_get_by_dev(f.file->f_mapping->host->i_rdev,
-					 FMODE_WRITE | FMODE_READ, NULL);
+					 FMODE_WRITE | FMODE_READ, NULL, NULL);
 	if (IS_ERR(reg->hr_bdev)) {
 		ret = PTR_ERR(reg->hr_bdev);
 		reg->hr_bdev = NULL;
diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index 4d11d60f493c..5e4db9a0c8e5 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -2616,7 +2616,7 @@ static int journal_init_dev(struct super_block *super,
 		if (jdev == super->s_dev)
 			blkdev_mode &= ~FMODE_EXCL;
 		journal->j_dev_bd = blkdev_get_by_dev(jdev, blkdev_mode,
-						      journal);
+						      journal, NULL);
 		journal->j_dev_mode = blkdev_mode;
 		if (IS_ERR(journal->j_dev_bd)) {
 			result = PTR_ERR(journal->j_dev_bd);
@@ -2632,7 +2632,8 @@ static int journal_init_dev(struct super_block *super,
 	}
 
 	journal->j_dev_mode = blkdev_mode;
-	journal->j_dev_bd = blkdev_get_by_path(jdev_name, blkdev_mode, journal);
+	journal->j_dev_bd = blkdev_get_by_path(jdev_name, blkdev_mode, journal,
+					       NULL);
 	if (IS_ERR(journal->j_dev_bd)) {
 		result = PTR_ERR(journal->j_dev_bd);
 		journal->j_dev_bd = NULL;
diff --git a/fs/super.c b/fs/super.c
index 34afe411cf2b..012ce1400803 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1248,7 +1248,7 @@ int get_tree_bdev(struct fs_context *fc,
 	if (!fc->source)
 		return invalf(fc, "No source specified");
 
-	bdev = blkdev_get_by_path(fc->source, mode, fc->fs_type);
+	bdev = blkdev_get_by_path(fc->source, mode, fc->fs_type, NULL);
 	if (IS_ERR(bdev)) {
 		errorf(fc, "%s: Can't open blockdev", fc->source);
 		return PTR_ERR(bdev);
@@ -1333,7 +1333,7 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
 	if (!(flags & SB_RDONLY))
 		mode |= FMODE_WRITE;
 
-	bdev = blkdev_get_by_path(dev_name, mode, fs_type);
+	bdev = blkdev_get_by_path(dev_name, mode, fs_type, NULL);
 	if (IS_ERR(bdev))
 		return ERR_CAST(bdev);
 
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 7e706255f165..5684c538eb76 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -386,7 +386,7 @@ xfs_blkdev_get(
 	int			error = 0;
 
 	*bdevp = blkdev_get_by_path(name, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
-				    mp);
+				    mp, NULL);
 	if (IS_ERR(*bdevp)) {
 		error = PTR_ERR(*bdevp);
 		xfs_warn(mp, "Invalid device [%s], error=%d", name, error);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 8ef209e3aa96..deb69eeab6bd 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -55,6 +55,8 @@ struct block_device {
 	struct super_block *	bd_super;
 	void *			bd_claiming;
 	void *			bd_holder;
+	const struct blk_holder_ops *bd_holder_ops;
+	struct mutex		bd_holder_lock;
 	/* The counter of freeze processes */
 	int			bd_fsfreeze_count;
 	int			bd_holders;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d89c2da14698..44f2a8bc57e8 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1470,10 +1470,15 @@ void blkdev_show(struct seq_file *seqf, off_t offset);
 #define BLKDEV_MAJOR_MAX	0
 #endif
 
+struct blk_holder_ops {
+};
+
+struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder,
+		const struct blk_holder_ops *hops);
 struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
-		void *holder);
-struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder);
-int bd_prepare_to_claim(struct block_device *bdev, void *holder);
+		void *holder, const struct blk_holder_ops *hops);
+int bd_prepare_to_claim(struct block_device *bdev, void *holder,
+		const struct blk_holder_ops *hops);
 void bd_abort_claiming(struct block_device *bdev, void *holder);
 void blkdev_put(struct block_device *bdev, fmode_t mode);
 
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 92e41ed292ad..801c411530d1 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -357,7 +357,7 @@ static int swsusp_swap_check(void)
 	root_swap = res;
 
 	hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device, FMODE_WRITE,
-			NULL);
+			NULL, NULL);
 	if (IS_ERR(hib_resume_bdev))
 		return PTR_ERR(hib_resume_bdev);
 
@@ -1524,7 +1524,7 @@ int swsusp_check(void)
 		mode |= FMODE_EXCL;
 
 	hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
-					    mode, &holder);
+					    mode, &holder, NULL);
 	if (!IS_ERR(hib_resume_bdev)) {
 		set_blocksize(hib_resume_bdev, PAGE_SIZE);
 		clear_page(swsusp_header);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 274bbf797480..cfbcf7d5705f 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2770,7 +2770,8 @@ static int claim_swapfile(struct swap_info_struct *p, struct inode *inode)
 
 	if (S_ISBLK(inode->i_mode)) {
 		p->bdev = blkdev_get_by_dev(inode->i_rdev,
-				   FMODE_READ | FMODE_WRITE | FMODE_EXCL, p);
+				   FMODE_READ | FMODE_WRITE | FMODE_EXCL, p,
+				   NULL);
 		if (IS_ERR(p->bdev)) {
 			error = PTR_ERR(p->bdev);
 			p->bdev = NULL;