[PATCH 8/8] btrfs: drop the redundant invalidate_bdev()

[Anand Jain <anand.jain@oracle.com>]

During the mount context btrfs_open_devices() calls invalidate_bdev()
for all the devices. So drop the invalidate_bdev() in open_ctree()
which is only for the btrfs_fs_devices::latest_bdev.

The call trace is as shown below.

btrfs_mount_root()
 |
 |_btrfs_parse_early_options (-o device only)
 | |_btrfs_scan_one_device
 |   |_btrfs_read_disk_super()
 |     |_read_cache_page_gfp()
 |
 |_btrfs_scan_one_device(mount-arg-dev only)
 | |_btrfs_read_disk_super()
 |   |_read_cache_page_gfp()
 |
 |
 |_btrfs_open_devices(fsid:all)
 |  |_btrfs_open_one_device()
 |    |_btrfs_get_bdev_and_sb()  <--- invalidate_bdev(fsid:all)
 |      |_btrfs_read_dev_super()
 |        |_btrfs_read_dev_one_super()
 |          |___bread()
 |
 |_btrfs_fill_super()
   |_btrfs_open_ctree()   <-- invalidate_bdev(latest_bdev) <-- redundant
     |_btrfs_read_dev_super(latest_bdev only)
       |_btrfs_read_dev_one_super(latest_bdev only)
         |___bread(latest_bdev)

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 fs/btrfs/disk-io.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 3cc50041c0b9..4f667c99dd16 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2553,8 +2553,6 @@ int open_ctree(struct super_block *sb,
 
 	__setup_root(tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID);
 
-	invalidate_bdev(fs_devices->latest_bdev);
-
 	/*
 	 * Read super block and check the signature bytes only
 	 */
-- 
2.7.0