1 files changed, 115 insertions, 0 deletions
diff --git a/libbtrfsutil/subvolume.c b/libbtrfsutil/subvolume.c
index 7ae8142c..6ac372ca 100644
--- a/libbtrfsutil/subvolume.c
+++ b/libbtrfsutil/subvolume.c
@@ -19,6 +19,8 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
@@ -123,3 +125,116 @@ PUBLIC enum btrfs_util_error btrfs_util_subvolume_id_fd(int fd,
 
 	return BTRFS_UTIL_OK;
 }
+
+static enum btrfs_util_error openat_parent_and_name(int dirfd, const char *path,
+						    char *name, size_t name_len,
+						    int *fd)
+{
+	char *tmp_path, *slash, *dirname, *basename;
+	size_t len;
+
+	/* Ignore trailing slashes. */
+	len = strlen(path);
+	while (len > 1 && path[len - 1] == '/')
+		len--;
+
+	tmp_path = malloc(len + 1);
+	if (!tmp_path)
+		return BTRFS_UTIL_ERROR_NO_MEMORY;
+	memcpy(tmp_path, path, len);
+	tmp_path[len] = '\0';
+
+	slash = memrchr(tmp_path, '/', len);
+	if (slash == tmp_path) {
+		dirname = "/";
+		basename = tmp_path + 1;
+	} else if (slash) {
+		*slash = '\0';
+		dirname = tmp_path;
+		basename = slash + 1;
+	} else {
+		dirname = ".";
+		basename = tmp_path;
+	}
+
+	len = strlen(basename);
+	if (len >= name_len) {
+		free(tmp_path);
+		errno = ENAMETOOLONG;
+		return BTRFS_UTIL_ERROR_INVALID_ARGUMENT;
+	}
+	memcpy(name, basename, len);
+	name[len] = '\0';
+
+	*fd = openat(dirfd, dirname, O_RDONLY | O_DIRECTORY);
+	if (*fd == -1) {
+		free(tmp_path);
+		return BTRFS_UTIL_ERROR_OPEN_FAILED;
+	}
+
+	free(tmp_path);
+	return BTRFS_UTIL_OK;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_create_subvolume(const char *path,
+							 int flags,
+							 uint64_t *async_transid,
+							 struct btrfs_util_qgroup_inherit *qgroup_inherit)
+{
+	char name[BTRFS_SUBVOL_NAME_MAX + 1];
+	enum btrfs_util_error err;
+	int parent_fd;
+
+	err = openat_parent_and_name(AT_FDCWD, path, name, sizeof(name),
+				     &parent_fd);
+	if (err)
+		return err;
+
+	err = btrfs_util_create_subvolume_fd(parent_fd, name, flags,
+					    async_transid, qgroup_inherit);
+	SAVE_ERRNO_AND_CLOSE(parent_fd);
+	return err;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_create_subvolume_fd(int parent_fd,
+							    const char *name,
+							    int flags,
+							    uint64_t *async_transid,
+							    struct btrfs_util_qgroup_inherit *qgroup_inherit)
+{
+	struct btrfs_ioctl_vol_args_v2 args = {};
+	size_t len;
+	int ret;
+
+	if (flags) {
+		errno = EINVAL;
+		return BTRFS_UTIL_ERROR_INVALID_ARGUMENT;
+	}
+
+	if (async_transid)
+		args.flags |= BTRFS_SUBVOL_CREATE_ASYNC;
+	if (qgroup_inherit) {
+		args.flags |= BTRFS_SUBVOL_QGROUP_INHERIT;
+		args.qgroup_inherit = (struct btrfs_qgroup_inherit *)qgroup_inherit;
+		args.size = (sizeof(*args.qgroup_inherit) +
+			     args.qgroup_inherit->num_qgroups *
+			     sizeof(args.qgroup_inherit->qgroups[0]));
+	}
+
+	len = strlen(name);
+	if (len >= sizeof(args.name)) {
+		errno = ENAMETOOLONG;
+		return BTRFS_UTIL_ERROR_INVALID_ARGUMENT;
+	}
+	memcpy(args.name, name, len);
+	args.name[len] = '\0';
+
+	ret = ioctl(parent_fd, BTRFS_IOC_SUBVOL_CREATE_V2, &args);
+	if (ret == -1)
+		return BTRFS_UTIL_ERROR_SUBVOL_CREATE_FAILED;
+
+	if (async_transid)
+		*async_transid = args.transid;
+
+	return BTRFS_UTIL_OK;
+}