X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=fs%2Fblock_dev.c;h=198aea66fe71c7d8cb24416be9332c41507173e7;hb=45568625feacf13f1450da6b8cec17bf97c5a3fd;hp=c25639e907bd21a194aecedc6c60a93fb4994375;hpb=73b39bb0a0feefc9b2f410e213f20a7d4f715682;p=firefly-linux-kernel-4.4.55.git

diff --git a/fs/block_dev.c b/fs/block_dev.c
index c25639e907bd..198aea66fe71 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -759,7 +759,7 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
 		return true;	 /* already a holder */
 	else if (bdev->bd_holder != NULL)
 		return false; 	 /* held by someone else */
-	else if (bdev->bd_contains == bdev)
+	else if (whole == bdev)
 		return true;  	 /* is a whole device which isn't held */
 
 	else if (whole->bd_holder == bd_may_claim)
@@ -1523,11 +1523,14 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 		WARN_ON_ONCE(bdev->bd_holders);
 		sync_blockdev(bdev);
 		kill_bdev(bdev);
+
+		bdev_write_inode(bdev);
 		/*
-		 * ->release can cause the queue to disappear, so flush all
-		 * dirty data before.
+		 * Detaching bdev inode from its wb in __destroy_inode()
+		 * is too late: the queue which embeds its bdi (along with
+		 * root wb) can be gone as soon as we put_disk() below.
 		 */
-		bdev_write_inode(bdev);
+		inode_detach_wb(bdev->bd_inode);
 	}
 	if (bdev->bd_contains == bdev) {
 		if (disk->fops->release)
@@ -1803,6 +1806,7 @@ void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg)
 	spin_lock(&blockdev_superblock->s_inode_list_lock);
 	list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) {
 		struct address_space *mapping = inode->i_mapping;
+		struct block_device *bdev;
 
 		spin_lock(&inode->i_lock);
 		if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) ||
@@ -1823,8 +1827,12 @@ void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg)
 		 */
 		iput(old_inode);
 		old_inode = inode;
+		bdev = I_BDEV(inode);
 
-		func(I_BDEV(inode), arg);
+		mutex_lock(&bdev->bd_mutex);
+		if (bdev->bd_openers)
+			func(bdev, arg);
+		mutex_unlock(&bdev->bd_mutex);
 
 		spin_lock(&blockdev_superblock->s_inode_list_lock);
 	}