Btrfs-progs: add function btrfs_get_subvol to get root_info of a subvol

We need a function which can get the root_info of a given
subvol. This is in preparation to add support for the show
sub-cli.

Signed-off-by: Anand Jain <anand.jain@oracle.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/btrfs-list.c b/btrfs-list.c
index 3bd305b3..247711d5 100644
--- a/btrfs-list.c
+++ b/btrfs-list.c
@@ -1468,6 +1468,44 @@ int btrfs_list_subvols_print(int fd, struct btrfs_list_filter_set *filter_set,
 	return 0;
 }
 
+int btrfs_get_subvol(int fd, struct root_info *the_ri)
+{
+	int ret = -1;
+	struct root_lookup rl;
+	struct rb_node *rbn;
+	struct root_info *ri;
+	u64 root_id = btrfs_list_get_path_rootid(fd);
+
+	if (btrfs_list_subvols(fd, &rl))
+		return 1;
+
+	rbn = rb_first(&rl.root);
+	while(rbn) {
+		ri = rb_entry(rbn, struct root_info, rb_node);
+		resolve_root(&rl, ri, root_id);
+		if (!comp_entry_with_rootid(the_ri, ri, 0)) {
+			memcpy(the_ri, ri, offsetof(struct root_info, path));
+			if (ri->path)
+				the_ri->path = strdup(ri->path);
+			else
+				the_ri->path = NULL;
+			if (ri->name)
+				the_ri->name = strdup(ri->name);
+			else
+				the_ri->name = NULL;
+			if (ri->full_path)
+				the_ri->full_path = strdup(ri->full_path);
+			else
+				the_ri->name = NULL;
+			ret = 0;
+			break;
+		}
+		rbn = rb_next(rbn);
+	}
+	__free_all_subvolumn(&rl);
+	return ret;
+}
+
 static int print_one_extent(int fd, struct btrfs_ioctl_search_header *sh,
 			    struct btrfs_file_extent_item *item,
 			    u64 found_gen, u64 *cache_dirid,