btrfs: rename btrfs_close_extra_device to btrfs_free_extra_devids

This function btrfs_close_extra_devices() is about freeing
extra devids which once it may have belonged to this filesystem.
So rename it and add the comment. The _devid suffix is
appropriate as this function won't handle devices which are
outside of the filesytem being mounted.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 798e602..bbbcbf8 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2758,10 +2758,10 @@ int open_ctree(struct super_block *sb,
 	}
 
 	/*
-	 * keep the device that is marked to be the target device for the
-	 * dev_replace procedure
+	 * Keep the devid that is marked to be the target device for the
+	 * device replace procedure
 	 */
-	btrfs_close_extra_devices(fs_devices, 0);
+	btrfs_free_extra_devids(fs_devices, 0);
 
 	if (!fs_devices->latest_bdev) {
 		btrfs_err(fs_info, "failed to read devices");
@@ -2824,7 +2824,7 @@ int open_ctree(struct super_block *sb,
 		goto fail_block_groups;
 	}
 
-	btrfs_close_extra_devices(fs_devices, 1);
+	btrfs_free_extra_devids(fs_devices, 1);
 
 	ret = btrfs_sysfs_add_fsid(fs_devices, NULL);
 	if (ret) {