Btrfs-progs: enhance btrfs subvol list only to show read-only snapshots

We want 'btrfs subvolume list' only to list readonly subvolumes, this patch set
introduces a new option 'r' to implement it.

You can use the command like that:

        btrfs subvolume list -r <path>

Original-Signed-off-by: Zhou Bo <zhoub-fnst@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/ctree.h b/ctree.h
index c55d0338..4bb66fff 100644
--- a/ctree.h
+++ b/ctree.h
@@ -139,6 +139,8 @@ static int btrfs_csum_sizes[] = { 4, 0 };
 #define BTRFS_FT_XATTR		8
 #define BTRFS_FT_MAX		9
 
+#define BTRFS_ROOT_SUBVOL_RDONLY	(1ULL << 0)
+
 /*
  * the key defines the order in the tree, and so it also defines (optimal)
  * block layout.  objectid corresonds to the inode number.  The flags