1 files changed, 35 insertions, 2 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 3c47614a4b32..2eca00ec4370 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -870,6 +870,7 @@ static void init_once(void *foo)
 #ifdef CONFIG_SYSFS
 	INIT_LIST_HEAD(&bdev->bd_holder_disks);
 #endif
+	bdev->bd_bdi = &noop_backing_dev_info;
 	inode_init_once(&ei->vfs_inode);
 	/* Initialize mutex for freeze. */
 	mutex_init(&bdev->bd_fsfreeze_mutex);
@@ -884,6 +885,10 @@ static void bdev_evict_inode(struct inode *inode)
 	spin_lock(&bdev_lock);
 	list_del_init(&bdev->bd_list);
 	spin_unlock(&bdev_lock);
+	if (bdev->bd_bdi != &noop_backing_dev_info) {
+		bdi_put(bdev->bd_bdi);
+		bdev->bd_bdi = &noop_backing_dev_info;
+	}
 }
 
 static const struct super_operations bdev_sops = {
@@ -954,6 +959,21 @@ static int bdev_set(struct inode *inode, void *data)
 
 static LIST_HEAD(all_bdevs);
 
+/*
+ * If there is a bdev inode for this device, unhash it so that it gets evicted
+ * as soon as last inode reference is dropped.
+ */
+void bdev_unhash_inode(dev_t dev)
+{
+	struct inode *inode;
+
+	inode = ilookup5(blockdev_superblock, hash(dev), bdev_test, &dev);
+	if (inode) {
+		remove_inode_hash(inode);
+		iput(inode);
+	}
+}
+
 struct block_device *bdget(dev_t dev)
 {
 	struct block_device *bdev;
@@ -971,7 +991,7 @@ struct block_device *bdget(dev_t dev)
 		bdev->bd_contains = NULL;
 		bdev->bd_super = NULL;
 		bdev->bd_inode = inode;
-		bdev->bd_block_size = (1 << inode->i_blkbits);
+		bdev->bd_block_size = i_blocksize(inode);
 		bdev->bd_part_count = 0;
 		bdev->bd_invalidated = 0;
 		inode->i_mode = S_IFBLK;
@@ -1025,13 +1045,22 @@ static struct block_device *bd_acquire(struct inode *inode)
 
 	spin_lock(&bdev_lock);
 	bdev = inode->i_bdev;
-	if (bdev) {
+	if (bdev && !inode_unhashed(bdev->bd_inode)) {
 		bdgrab(bdev);
 		spin_unlock(&bdev_lock);
 		return bdev;
 	}
 	spin_unlock(&bdev_lock);
 
+	/*
+	 * i_bdev references block device inode that was already shut down
+	 * (corresponding device got removed).  Remove the reference and look
+	 * up block device inode again just in case new device got
+	 * reestablished under the same device number.
+	 */
+	if (bdev)
+		bd_forget(inode);
+
 	bdev = bdget(inode->i_rdev);
 	if (bdev) {
 		spin_lock(&bdev_lock);
@@ -1527,6 +1556,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 		bdev->bd_disk = disk;
 		bdev->bd_queue = disk->queue;
 		bdev->bd_contains = bdev;
+		if (bdev->bd_bdi == &noop_backing_dev_info)
+			bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info);
 
 		if (!partno) {
 			ret = -ENXIO;
@@ -1622,6 +1653,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 	bdev->bd_disk = NULL;
 	bdev->bd_part = NULL;
 	bdev->bd_queue = NULL;
+	bdi_put(bdev->bd_bdi);
+	bdev->bd_bdi = &noop_backing_dev_info;
 	if (bdev != bdev->bd_contains)
 		__blkdev_put(bdev->bd_contains, mode, 1);
 	bdev->bd_contains = NULL;