X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=send-utils.c;h=b5289e76ae9d59015101cda0be8b67611ce12f27;hb=992aa558397e519d2251cdc6c4d3a9e019b240a0;hp=bc0feb833b9e4c9bffe83f33d0753c7e71207768;hpb=7c04a4444e5cec0691cb91660011fb614ddace94;p=platform%2Fupstream%2Fbtrfs-progs.git

diff --git a/send-utils.c b/send-utils.c
index bc0feb8..b5289e7 100644
--- a/send-utils.c
+++ b/send-utils.c
@@ -16,23 +16,161 @@
  * Boston, MA 021110-1307, USA.
  */
 
+#include <unistd.h>
+#include <fcntl.h>
 #include <sys/ioctl.h>
+#include <uuid/uuid.h>
+#include <limits.h>
+#include <errno.h>
 
 #include "ctree.h"
 #include "send-utils.h"
 #include "ioctl.h"
 #include "btrfs-list.h"
 
+static int btrfs_subvolid_resolve_sub(int fd, char *path, size_t *path_len,
+				      u64 subvol_id);
+
+static int btrfs_get_root_id_by_sub_path(int mnt_fd, const char *sub_path,
+					 u64 *root_id)
+{
+	int ret;
+	int subvol_fd;
+
+	subvol_fd = openat(mnt_fd, sub_path, O_RDONLY);
+	if (subvol_fd < 0) {
+		ret = -errno;
+		fprintf(stderr, "ERROR: open %s failed. %s\n", sub_path,
+			strerror(-ret));
+		return ret;
+	}
+
+	ret = btrfs_list_get_path_rootid(subvol_fd, root_id);
+	close(subvol_fd);
+	return ret;
+}
+
+static int btrfs_read_root_item_raw(int mnt_fd, u64 root_id, size_t buf_len,
+				    u32 *read_len, void *buf)
+{
+	int ret;
+	struct btrfs_ioctl_search_args args;
+	struct btrfs_ioctl_search_key *sk = &args.key;
+	struct btrfs_ioctl_search_header *sh;
+	unsigned long off = 0;
+	int found = 0;
+	int i;
+
+	*read_len = 0;
+	memset(&args, 0, sizeof(args));
+
+	sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
+
+	/*
+	 * there may be more than one ROOT_ITEM key if there are
+	 * snapshots pending deletion, we have to loop through
+	 * them.
+	 */
+	sk->min_objectid = root_id;
+	sk->max_objectid = root_id;
+	sk->max_type = BTRFS_ROOT_ITEM_KEY;
+	sk->min_type = BTRFS_ROOT_ITEM_KEY;
+	sk->max_offset = (u64)-1;
+	sk->max_transid = (u64)-1;
+	sk->nr_items = 4096;
+
+	while (1) {
+		ret = ioctl(mnt_fd, BTRFS_IOC_TREE_SEARCH, &args);
+		if (ret < 0) {
+			fprintf(stderr,
+				"ERROR: can't perform the search - %m\n");
+			return 0;
+		}
+		/* the ioctl returns the number of item it found in nr_items */
+		if (sk->nr_items == 0)
+			break;
+
+		off = 0;
+		for (i = 0; i < sk->nr_items; i++) {
+			struct btrfs_root_item *item;
+			sh = (struct btrfs_ioctl_search_header *)(args.buf +
+								  off);
+
+			off += sizeof(*sh);
+			item = (struct btrfs_root_item *)(args.buf + off);
+			off += btrfs_search_header_len(sh);
+
+			sk->min_objectid = btrfs_search_header_objectid(sh);
+			sk->min_type = btrfs_search_header_type(sh);
+			sk->min_offset = btrfs_search_header_offset(sh);
+
+			if (btrfs_search_header_objectid(sh) > root_id)
+				break;
+
+			if (btrfs_search_header_objectid(sh) == root_id &&
+			    btrfs_search_header_type(sh) == BTRFS_ROOT_ITEM_KEY) {
+				if (btrfs_search_header_len(sh) > buf_len) {
+					/* btrfs-progs is too old for kernel */
+					fprintf(stderr,
+						"ERROR: buf for read_root_item_raw() is too small, get newer btrfs tools!\n");
+					return -EOVERFLOW;
+				}
+				memcpy(buf, item, btrfs_search_header_len(sh));
+				*read_len = btrfs_search_header_len(sh);
+				found = 1;
+			}
+		}
+		if (sk->min_offset < (u64)-1)
+			sk->min_offset++;
+		else
+			break;
+
+		if (sk->min_type != BTRFS_ROOT_ITEM_KEY ||
+		    sk->min_objectid != root_id)
+			break;
+	}
+
+	return found ? 0 : -ENOENT;
+}
+
+/*
+ * Read a root item from the tree. In case we detect a root item smaller then
+ * sizeof(root_item), we know it's an old version of the root structure and
+ * initialize all new fields to zero. The same happens if we detect mismatching
+ * generation numbers as then we know the root was once mounted with an older
+ * kernel that was not aware of the root item structure change.
+ */
+static int btrfs_read_root_item(int mnt_fd, u64 root_id,
+				struct btrfs_root_item *item)
+{
+	int ret;
+	u32 read_len;
+
+	ret = btrfs_read_root_item_raw(mnt_fd, root_id, sizeof(*item),
+				       &read_len, item);
+	if (ret)
+		return ret;
+
+	if (read_len < sizeof(*item) ||
+	    btrfs_root_generation(item) != btrfs_root_generation_v2(item))
+		memset(&item->generation_v2, 0,
+			sizeof(*item) - offsetof(struct btrfs_root_item,
+						 generation_v2));
+
+	return 0;
+}
+
+#ifdef BTRFS_COMPAT_SEND_NO_UUID_TREE
 static struct rb_node *tree_insert(struct rb_root *root,
 				   struct subvol_info *si,
 				   enum subvol_search_type type)
 {
-	struct rb_node ** p = &root->rb_node;
-	struct rb_node * parent = NULL;
+	struct rb_node **p = &root->rb_node;
+	struct rb_node *parent = NULL;
 	struct subvol_info *entry;
 	__s64 comp;
 
-	while(*p) {
+	while (*p) {
 		parent = *p;
 		if (type == subvol_search_by_received_uuid) {
 			entry = rb_entry(parent, struct subvol_info,
@@ -87,17 +225,146 @@ static struct rb_node *tree_insert(struct rb_root *root,
 	}
 	return NULL;
 }
+#endif
+
+int btrfs_subvolid_resolve(int fd, char *path, size_t path_len, u64 subvol_id)
+{
+	if (path_len < 1)
+		return -EOVERFLOW;
+	path[0] = '\0';
+	path_len--;
+	path[path_len] = '\0';
+	return btrfs_subvolid_resolve_sub(fd, path, &path_len, subvol_id);
+}
+
+static int btrfs_subvolid_resolve_sub(int fd, char *path, size_t *path_len,
+				      u64 subvol_id)
+{
+	int ret;
+	struct btrfs_ioctl_search_args search_arg;
+	struct btrfs_ioctl_ino_lookup_args ino_lookup_arg;
+	struct btrfs_ioctl_search_header *search_header;
+	struct btrfs_root_ref *backref_item;
+
+	if (subvol_id == BTRFS_FS_TREE_OBJECTID) {
+		if (*path_len < 1)
+			return -EOVERFLOW;
+		*path = '\0';
+		(*path_len)--;
+		return 0;
+	}
+
+	memset(&search_arg, 0, sizeof(search_arg));
+	search_arg.key.tree_id = BTRFS_ROOT_TREE_OBJECTID;
+	search_arg.key.min_objectid = subvol_id;
+	search_arg.key.max_objectid = subvol_id;
+	search_arg.key.min_type = BTRFS_ROOT_BACKREF_KEY;
+	search_arg.key.max_type = BTRFS_ROOT_BACKREF_KEY;
+	search_arg.key.max_offset = (u64)-1;
+	search_arg.key.max_transid = (u64)-1;
+	search_arg.key.nr_items = 1;
+	ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &search_arg);
+	if (ret < 0) {
+		fprintf(stderr,
+			"ioctl(BTRFS_IOC_TREE_SEARCH, subvol_id %llu) ret=%d, error: %m\n",
+			(unsigned long long)subvol_id, ret);
+		return ret;
+	}
+
+	if (search_arg.key.nr_items < 1) {
+		fprintf(stderr,
+			"failed to lookup subvol_id %llu!\n",
+			(unsigned long long)subvol_id);
+		return -ENOENT;
+	}
+	search_header = (struct btrfs_ioctl_search_header *)search_arg.buf;
+	backref_item = (struct btrfs_root_ref *)(search_header + 1);
+	if (btrfs_search_header_offset(search_header)
+	    != BTRFS_FS_TREE_OBJECTID) {
+		int sub_ret;
+
+		sub_ret = btrfs_subvolid_resolve_sub(fd, path, path_len,
+				btrfs_search_header_offset(search_header));
+		if (sub_ret)
+			return sub_ret;
+		if (*path_len < 1)
+			return -EOVERFLOW;
+		strcat(path, "/");
+		(*path_len)--;
+	}
+
+	if (btrfs_stack_root_ref_dirid(backref_item) !=
+	    BTRFS_FIRST_FREE_OBJECTID) {
+		int len;
+
+		memset(&ino_lookup_arg, 0, sizeof(ino_lookup_arg));
+		ino_lookup_arg.treeid =
+			btrfs_search_header_offset(search_header);
+		ino_lookup_arg.objectid =
+			btrfs_stack_root_ref_dirid(backref_item);
+		ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP, &ino_lookup_arg);
+		if (ret < 0) {
+			fprintf(stderr,
+				"ioctl(BTRFS_IOC_INO_LOOKUP) ret=%d, error: %m\n",
+				ret);
+			return ret;
+		}
+
+		len = strlen(ino_lookup_arg.name);
+		if (*path_len < len)
+			return -EOVERFLOW;
+		strcat(path, ino_lookup_arg.name);
+		(*path_len) -= len;
+	}
+
+	if (*path_len < btrfs_stack_root_ref_name_len(backref_item))
+		return -EOVERFLOW;
+	strncat(path, (char *)(backref_item + 1),
+		btrfs_stack_root_ref_name_len(backref_item));
+	(*path_len) -= btrfs_stack_root_ref_name_len(backref_item);
+	return 0;
+}
+
+#ifdef BTRFS_COMPAT_SEND_NO_UUID_TREE
+static int count_bytes(void *buf, int len, char b)
+{
+	int cnt = 0;
+	int i;
+
+	for (i = 0; i < len; i++) {
+		if (((char *)buf)[i] == b)
+			cnt++;
+	}
+	return cnt;
+}
+
+void subvol_uuid_search_add(struct subvol_uuid_search *s,
+			    struct subvol_info *si)
+{
+	int cnt;
+
+	tree_insert(&s->root_id_subvols, si, subvol_search_by_root_id);
+	tree_insert(&s->path_subvols, si, subvol_search_by_path);
+
+	cnt = count_bytes(si->uuid, BTRFS_UUID_SIZE, 0);
+	if (cnt != BTRFS_UUID_SIZE)
+		tree_insert(&s->local_subvols, si, subvol_search_by_uuid);
+	cnt = count_bytes(si->received_uuid, BTRFS_UUID_SIZE, 0);
+	if (cnt != BTRFS_UUID_SIZE)
+		tree_insert(&s->received_subvols, si,
+				subvol_search_by_received_uuid);
+}
 
 static struct subvol_info *tree_search(struct rb_root *root,
 				       u64 root_id, const u8 *uuid,
 				       u64 stransid, const char *path,
 				       enum subvol_search_type type)
 {
-	struct rb_node * n = root->rb_node;
+	struct rb_node *n = root->rb_node;
 	struct subvol_info *entry;
 	__s64 comp;
 
-	while(n) {
+	while (n) {
 		if (type == subvol_search_by_received_uuid) {
 			entry = rb_entry(n, struct subvol_info,
 					rb_received_node);
@@ -115,7 +382,8 @@ static struct subvol_info *tree_search(struct rb_root *root,
 			entry = rb_entry(n, struct subvol_info, rb_local_node);
 			comp = memcmp(entry->uuid, uuid, BTRFS_UUID_SIZE);
 		} else if (type == subvol_search_by_root_id) {
-			entry = rb_entry(n, struct subvol_info, rb_root_id_node);
+			entry = rb_entry(n, struct subvol_info,
+					 rb_root_id_node);
 			comp = entry->root_id - root_id;
 		} else if (type == subvol_search_by_path) {
 			entry = rb_entry(n, struct subvol_info, rb_path_node);
@@ -133,35 +401,10 @@ static struct subvol_info *tree_search(struct rb_root *root,
 	return NULL;
 }
 
-static int count_bytes(void *buf, int len, char b)
-{
-	int cnt = 0;
-	int i;
-	for (i = 0; i < len; i++) {
-		if (((char*)buf)[i] == b)
-			cnt++;
-	}
-	return cnt;
-}
-
-void subvol_uuid_search_add(struct subvol_uuid_search *s,
-			    struct subvol_info *si)
-{
-	int cnt;
-
-	tree_insert(&s->root_id_subvols, si, subvol_search_by_root_id);
-	tree_insert(&s->path_subvols, si, subvol_search_by_path);
-
-	cnt = count_bytes(si->uuid, BTRFS_UUID_SIZE, 0);
-	if (cnt != BTRFS_UUID_SIZE)
-		tree_insert(&s->local_subvols, si, subvol_search_by_uuid);
-	cnt = count_bytes(si->received_uuid, BTRFS_UUID_SIZE, 0);
-	if (cnt != BTRFS_UUID_SIZE)
-		tree_insert(&s->received_subvols, si,
-				subvol_search_by_received_uuid);
-}
-
-struct subvol_info *subvol_uuid_search(struct subvol_uuid_search *s,
+/*
+ * this function will be only called if kernel doesn't support uuid tree.
+ */
+static struct subvol_info *subvol_uuid_search_old(struct subvol_uuid_search *s,
 				       u64 root_id, const u8 *uuid, u64 transid,
 				       const char *path,
 				       enum subvol_search_type type)
@@ -179,7 +422,145 @@ struct subvol_info *subvol_uuid_search(struct subvol_uuid_search *s,
 		return NULL;
 	return tree_search(root, root_id, uuid, transid, path, type);
 }
+#else
+void subvol_uuid_search_add(struct subvol_uuid_search *s,
+			    struct subvol_info *si)
+{
+	if (si) {
+		free(si->path);
+		free(si);
+	}
+}
+#endif
+
+struct subvol_info *subvol_uuid_search(struct subvol_uuid_search *s,
+				       u64 root_id, const u8 *uuid, u64 transid,
+				       const char *path,
+				       enum subvol_search_type type)
+{
+	struct subvol_info *si;
+
+	si = subvol_uuid_search2(s, root_id, uuid, transid, path, type);
+	if (IS_ERR(si))
+		return NULL;
+	return si;
+}
+
+struct subvol_info *subvol_uuid_search2(struct subvol_uuid_search *s,
+				       u64 root_id, const u8 *uuid, u64 transid,
+				       const char *path,
+				       enum subvol_search_type type)
+{
+	int ret = 0;
+	struct btrfs_root_item root_item;
+	struct subvol_info *info = NULL;
+
+#ifdef BTRFS_COMPAT_SEND_NO_UUID_TREE
+	if (!s->uuid_tree_existed)
+		return subvol_uuid_search_old(s, root_id, uuid, transid,
+					     path, type);
+#endif
+	switch (type) {
+	case subvol_search_by_received_uuid:
+		ret = btrfs_lookup_uuid_received_subvol_item(s->mnt_fd, uuid,
+							     &root_id);
+		break;
+	case subvol_search_by_uuid:
+		ret = btrfs_lookup_uuid_subvol_item(s->mnt_fd, uuid, &root_id);
+		break;
+	case subvol_search_by_root_id:
+		break;
+	case subvol_search_by_path:
+		ret = btrfs_get_root_id_by_sub_path(s->mnt_fd, path, &root_id);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	if (ret)
+		goto out;
+
+	ret = btrfs_read_root_item(s->mnt_fd, root_id, &root_item);
+	if (ret)
+		goto out;
+
+	info = calloc(1, sizeof(*info));
+	if (!info) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	info->root_id = root_id;
+	memcpy(info->uuid, root_item.uuid, BTRFS_UUID_SIZE);
+	memcpy(info->received_uuid, root_item.received_uuid, BTRFS_UUID_SIZE);
+	memcpy(info->parent_uuid, root_item.parent_uuid, BTRFS_UUID_SIZE);
+	info->ctransid = btrfs_root_ctransid(&root_item);
+	info->otransid = btrfs_root_otransid(&root_item);
+	info->stransid = btrfs_root_stransid(&root_item);
+	info->rtransid = btrfs_root_rtransid(&root_item);
+	if (type == subvol_search_by_path) {
+		info->path = strdup(path);
+		if (!info->path) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	} else {
+		info->path = malloc(PATH_MAX);
+		if (!info->path) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		ret = btrfs_subvolid_resolve(s->mnt_fd, info->path,
+					     PATH_MAX, root_id);
+	}
+
+out:
+	if (ret) {
+		if (info) {
+			free(info->path);
+			free(info);
+		}
+		return ERR_PTR(ret);
+	}
+
+	return info;
+}
+
+#ifdef BTRFS_COMPAT_SEND_NO_UUID_TREE
+static int is_uuid_tree_supported(int fd)
+{
+	int ret;
+	struct btrfs_ioctl_search_args args;
+	struct btrfs_ioctl_search_key *sk = &args.key;
+
+	memset(&args, 0, sizeof(args));
+
+	sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
+
+	sk->min_objectid = BTRFS_UUID_TREE_OBJECTID;
+	sk->max_objectid = BTRFS_UUID_TREE_OBJECTID;
+	sk->max_type = BTRFS_ROOT_ITEM_KEY;
+	sk->min_type = BTRFS_ROOT_ITEM_KEY;
+	sk->max_offset = (u64)-1;
+	sk->max_transid = (u64)-1;
+	sk->nr_items = 1;
+
+	ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
+	if (ret < 0)
+		return ret;
+
+	/* the ioctl returns the number of item it found in nr_items */
+	if (sk->nr_items == 0)
+		return 0;
+
+	return 1;
+}
 
+/*
+ * this function is mainly used to read all root items
+ * it will be only used when we use older kernel which uuid
+ * tree is not supported yet
+ */
 int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
 {
 	int ret;
@@ -187,14 +568,30 @@ int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
 	struct btrfs_ioctl_search_key *sk = &args.key;
 	struct btrfs_ioctl_search_header *sh;
 	struct btrfs_root_item *root_item_ptr;
-	struct btrfs_root_item root_item;
+	struct btrfs_root_item root_item = {};
 	struct subvol_info *si = NULL;
 	int root_item_valid = 0;
 	unsigned long off = 0;
 	int i;
-	int e;
 	char *path;
 
+	s->mnt_fd = mnt_fd;
+
+	s->root_id_subvols = RB_ROOT;
+	s->local_subvols = RB_ROOT;
+	s->received_subvols = RB_ROOT;
+	s->path_subvols = RB_ROOT;
+
+	ret = is_uuid_tree_supported(mnt_fd);
+	if (ret < 0) {
+		fprintf(stderr,
+			"ERROR: check if we support uuid tree fails - %m\n");
+		return ret;
+	} else if (ret) {
+		/* uuid tree is supported */
+		s->uuid_tree_existed = 1;
+		return 0;
+	}
 	memset(&args, 0, sizeof(args));
 
 	sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
@@ -206,12 +603,10 @@ int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
 	sk->max_type = BTRFS_ROOT_BACKREF_KEY;
 	sk->nr_items = 4096;
 
-	while(1) {
+	while (1) {
 		ret = ioctl(mnt_fd, BTRFS_IOC_TREE_SEARCH, &args);
-		e = errno;
 		if (ret < 0) {
-			fprintf(stderr, "ERROR: can't perform the search- %s\n",
-				strerror(e));
+			fprintf(stderr, "ERROR: can't perform the search - %m\n");
 			return ret;
 		}
 		if (sk->nr_items == 0)
@@ -224,14 +619,19 @@ int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
 								  off);
 			off += sizeof(*sh);
 
-			if ((sh->objectid != 5 &&
-			    sh->objectid < BTRFS_FIRST_FREE_OBJECTID) ||
-			    sh->objectid > BTRFS_LAST_FREE_OBJECTID)
+			if ((btrfs_search_header_objectid(sh) != 5 &&
+			     btrfs_search_header_objectid(sh)
+			     < BTRFS_FIRST_FREE_OBJECTID) ||
+			    btrfs_search_header_objectid(sh)
+			    > BTRFS_LAST_FREE_OBJECTID) {
 				goto skip;
+			}
 
-			if (sh->type == BTRFS_ROOT_ITEM_KEY) {
+			if (btrfs_search_header_type(sh)
+			    == BTRFS_ROOT_ITEM_KEY) {
 				/* older kernels don't have uuids+times */
-				if (sh->len < sizeof(root_item)) {
+				if (btrfs_search_header_len(sh)
+				    < sizeof(root_item)) {
 					root_item_valid = 0;
 					goto skip;
 				}
@@ -240,13 +640,14 @@ int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
 				memcpy(&root_item, root_item_ptr,
 						sizeof(root_item));
 				root_item_valid = 1;
-			} else if (sh->type == BTRFS_ROOT_BACKREF_KEY ||
+			} else if (btrfs_search_header_type(sh)
+				   == BTRFS_ROOT_BACKREF_KEY ||
 				   root_item_valid) {
 				if (!root_item_valid)
 					goto skip;
 
 				path = btrfs_list_path_for_root(mnt_fd,
-								sh->objectid);
+					btrfs_search_header_objectid(sh));
 				if (!path)
 					path = strdup("");
 				if (IS_ERR(path)) {
@@ -254,12 +655,12 @@ int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
 					fprintf(stderr, "ERROR: unable to "
 							"resolve path "
 							"for root %llu\n",
-							sh->objectid);
+						btrfs_search_header_objectid(sh));
 					goto out;
 				}
 
 				si = calloc(1, sizeof(*si));
-				si->root_id = sh->objectid;
+				si->root_id = btrfs_search_header_objectid(sh);
 				memcpy(si->uuid, root_item.uuid,
 						BTRFS_UUID_SIZE);
 				memcpy(si->parent_uuid, root_item.parent_uuid,
@@ -279,15 +680,15 @@ int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
 			}
 
 skip:
-			off += sh->len;
+			off += btrfs_search_header_len(sh);
 
 			/*
 			 * record the mins in sk so we can make sure the
 			 * next search doesn't repeat this root
 			 */
-			sk->min_objectid = sh->objectid;
-			sk->min_offset = sh->offset;
-			sk->min_type = sh->type;
+			sk->min_objectid = btrfs_search_header_objectid(sh);
+			sk->min_offset = btrfs_search_header_offset(sh);
+			sk->min_type = btrfs_search_header_type(sh);
 		}
 		sk->nr_items = 4096;
 		if (sk->min_offset < (u64)-1)
@@ -304,15 +705,14 @@ out:
 	return ret;
 }
 
-/*
- * It's safe to call this function even without the subvol_uuid_search_init()
- * call before as long as the subvol_uuid_search structure is all-zero.
- */
 void subvol_uuid_search_finit(struct subvol_uuid_search *s)
 {
 	struct rb_root *root = &s->root_id_subvols;
 	struct rb_node *node;
 
+	if (!s->uuid_tree_existed)
+		return;
+
 	while ((node = rb_first(root))) {
 		struct subvol_info *entry =
 			rb_entry(node, struct subvol_info, rb_root_id_node);
@@ -327,28 +727,56 @@ void subvol_uuid_search_finit(struct subvol_uuid_search *s)
 	s->received_subvols = RB_ROOT;
 	s->path_subvols = RB_ROOT;
 }
+#else
+int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
+{
+	s->mnt_fd = mnt_fd;
 
-char *path_cat(const char *p1, const char *p2)
+	return 0;
+}
+
+void subvol_uuid_search_finit(struct subvol_uuid_search *s)
+{
+}
+#endif
+
+int path_cat_out(char *out, const char *p1, const char *p2)
 {
 	int p1_len = strlen(p1);
 	int p2_len = strlen(p2);
-	char *new = malloc(p1_len + p2_len + 2);
+
+	if (p1_len + p2_len + 2 >= PATH_MAX)
+		return -ENAMETOOLONG;
 
 	if (p1_len && p1[p1_len - 1] == '/')
 		p1_len--;
 	if (p2_len && p2[p2_len - 1] == '/')
 		p2_len--;
-	sprintf(new, "%.*s/%.*s", p1_len, p1, p2_len, p2);
-	return new;
+	sprintf(out, "%.*s/%.*s", p1_len, p1, p2_len, p2);
+
+	return 0;
 }
 
+__attribute__((deprecated))
+char *path_cat(const char *p1, const char *p2)
+{
+	int p1_len = strlen(p1);
+	int p2_len = strlen(p2);
+	char *new = malloc(p1_len + p2_len + 2);
 
-char *path_cat3(const char *p1, const char *p2, const char *p3)
+	path_cat_out(new, p1, p2);
+
+	return new;
+}
+
+int path_cat3_out(char *out, const char *p1, const char *p2, const char *p3)
 {
 	int p1_len = strlen(p1);
 	int p2_len = strlen(p2);
 	int p3_len = strlen(p3);
-	char *new = malloc(p1_len + p2_len + p3_len + 3);
+
+	if (p1_len + p2_len + p3_len + 3 >= PATH_MAX)
+		return -ENAMETOOLONG;
 
 	if (p1_len && p1[p1_len - 1] == '/')
 		p1_len--;
@@ -356,7 +784,20 @@ char *path_cat3(const char *p1, const char *p2, const char *p3)
 		p2_len--;
 	if (p3_len && p3[p3_len - 1] == '/')
 		p3_len--;
-	sprintf(new, "%.*s/%.*s/%.*s", p1_len, p1, p2_len, p2, p3_len, p3);
-	return new;
+	sprintf(out, "%.*s/%.*s/%.*s", p1_len, p1, p2_len, p2, p3_len, p3);
+
+	return 0;
 }
 
+__attribute__((deprecated))
+char *path_cat3(const char *p1, const char *p2, const char *p3)
+{
+	int p1_len = strlen(p1);
+	int p2_len = strlen(p2);
+	int p3_len = strlen(p3);
+	char *new = malloc(p1_len + p2_len + p3_len + 3);
+
+	path_cat3_out(new, p1, p2, p3);
+
+	return new;
+}