btrfs-progs: fsck-tests: Introduce test case with keyed data backref with the extent...
[platform/upstream/btrfs-progs.git] / send-utils.c
index a43d47e..b5289e7 100644 (file)
  * 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"
 
-/* btrfs-list.c */
-char *path_for_root(int fd, u64 root);
+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,
@@ -62,6 +198,8 @@ static struct rb_node *tree_insert(struct rb_root *root,
                        entry = rb_entry(parent, struct subvol_info,
                                        rb_path_node);
                        comp = strcmp(entry->path, si->path);
+               } else {
+                       BUG();
                }
 
                if (comp < 0)
@@ -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);
@@ -115,11 +382,14 @@ 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);
                        comp = strcmp(entry->path, path);
+               } else {
+                       BUG();
                }
                if (comp < 0)
                        n = n->rb_left;
@@ -131,35 +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)
@@ -177,7 +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;
@@ -185,14 +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;
@@ -204,12 +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)
@@ -222,14 +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_FREE_INO_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;
                                }
@@ -238,11 +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 = path_for_root(mnt_fd, sh->objectid);
+                               path = btrfs_list_path_for_root(mnt_fd,
+                                       btrfs_search_header_objectid(sh));
                                if (!path)
                                        path = strdup("");
                                if (IS_ERR(path)) {
@@ -250,12 +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,
@@ -271,20 +676,19 @@ int subvol_uuid_search_init(int mnt_fd, struct subvol_uuid_search *s)
                                subvol_uuid_search_add(s, si);
                                root_item_valid = 0;
                        } else {
-                               root_item_valid = 0;
                                goto skip;
                        }
 
 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)
@@ -301,28 +705,78 @@ out:
        return ret;
 }
 
+void subvol_uuid_search_finit(struct subvol_uuid_search *s)
+{
+       struct rb_root *root = &s->root_id_subvols;
+       struct rb_node *node;
 
-char *path_cat(const char *p1, const char *p2)
+       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);
+
+               free(entry->path);
+               rb_erase(node, root);
+               free(entry);
+       }
+
+       s->root_id_subvols = RB_ROOT;
+       s->local_subvols = RB_ROOT;
+       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;
+
+       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 + 3);
+
+       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 + 4);
+
+       if (p1_len + p2_len + p3_len + 3 >= PATH_MAX)
+               return -ENAMETOOLONG;
 
        if (p1_len && p1[p1_len - 1] == '/')
                p1_len--;
@@ -330,7 +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;
+}