btrfs-progs: configure: check if xmlto exists at configure time
[platform/upstream/btrfs-progs.git] / libbtrfsutil / subvolume.c
index 965376e..867b3e1 100644 (file)
@@ -27,6 +27,7 @@
 #include <sys/types.h>
 #include <sys/vfs.h>
 #include <linux/magic.h>
+#include "stubs.h"
 
 #include "btrfsutil_internal.h"
 
@@ -690,3 +691,692 @@ PUBLIC enum btrfs_util_error btrfs_util_create_subvolume_fd(int parent_fd,
 
        return BTRFS_UTIL_OK;
 }
+
+#define BTRFS_UTIL_SUBVOLUME_ITERATOR_CLOSE_FD (1 << 30)
+
+struct search_stack_entry {
+       struct btrfs_ioctl_search_args search;
+       size_t items_pos, buf_off;
+       size_t path_len;
+};
+
+struct btrfs_util_subvolume_iterator {
+       int fd;
+       int flags;
+
+       struct search_stack_entry *search_stack;
+       size_t search_stack_len;
+       size_t search_stack_capacity;
+
+       char *cur_path;
+       size_t cur_path_capacity;
+};
+
+static enum btrfs_util_error append_to_search_stack(struct btrfs_util_subvolume_iterator *iter,
+                                                   uint64_t tree_id,
+                                                   size_t path_len)
+{
+       struct search_stack_entry *entry;
+
+       if (iter->search_stack_len >= iter->search_stack_capacity) {
+               size_t new_capacity = iter->search_stack_capacity * 2;
+               struct search_stack_entry *new_search_stack;
+
+               new_search_stack = reallocarray(iter->search_stack,
+                                               new_capacity,
+                                               sizeof(*iter->search_stack));
+               if (!new_search_stack)
+                       return BTRFS_UTIL_ERROR_NO_MEMORY;
+
+               iter->search_stack_capacity = new_capacity;
+               iter->search_stack = new_search_stack;
+       }
+
+       entry = &iter->search_stack[iter->search_stack_len++];
+
+       memset(&entry->search, 0, sizeof(entry->search));
+       entry->search.key.tree_id = BTRFS_ROOT_TREE_OBJECTID;
+       entry->search.key.min_objectid = tree_id;
+       entry->search.key.max_objectid = tree_id;
+       entry->search.key.min_type = BTRFS_ROOT_REF_KEY;
+       entry->search.key.max_type = BTRFS_ROOT_REF_KEY;
+       entry->search.key.min_offset = 0;
+       entry->search.key.max_offset = UINT64_MAX;
+       entry->search.key.min_transid = 0;
+       entry->search.key.max_transid = UINT64_MAX;
+       entry->search.key.nr_items = 0;
+
+       entry->items_pos = 0;
+       entry->buf_off = 0;
+
+       entry->path_len = path_len;
+
+       return BTRFS_UTIL_OK;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_create_subvolume_iterator(const char *path,
+                                                                 uint64_t top,
+                                                                 int flags,
+                                                                 struct btrfs_util_subvolume_iterator **ret)
+{
+       enum btrfs_util_error err;
+       int fd;
+
+       fd = open(path, O_RDONLY);
+       if (fd == -1)
+               return BTRFS_UTIL_ERROR_OPEN_FAILED;
+
+       err = btrfs_util_create_subvolume_iterator_fd(fd, top, flags, ret);
+       if (err)
+               SAVE_ERRNO_AND_CLOSE(fd);
+       else
+               (*ret)->flags |= BTRFS_UTIL_SUBVOLUME_ITERATOR_CLOSE_FD;
+
+       return err;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_create_subvolume_iterator_fd(int fd,
+                                                                    uint64_t top,
+                                                                    int flags,
+                                                                    struct btrfs_util_subvolume_iterator **ret)
+{
+       struct btrfs_util_subvolume_iterator *iter;
+       enum btrfs_util_error err;
+
+       if (flags & ~BTRFS_UTIL_SUBVOLUME_ITERATOR_MASK) {
+               errno = EINVAL;
+               return BTRFS_UTIL_ERROR_INVALID_ARGUMENT;
+       }
+
+       if (top == 0) {
+               err = btrfs_util_is_subvolume_fd(fd);
+               if (err)
+                       return err;
+
+               err = btrfs_util_subvolume_id_fd(fd, &top);
+               if (err)
+                       return err;
+       }
+
+       iter = malloc(sizeof(*iter));
+       if (!iter)
+               return BTRFS_UTIL_ERROR_NO_MEMORY;
+
+       iter->fd = fd;
+       iter->flags = flags;
+
+       iter->search_stack_len = 0;
+       iter->search_stack_capacity = 4;
+       iter->search_stack = malloc(sizeof(*iter->search_stack) *
+                                   iter->search_stack_capacity);
+       if (!iter->search_stack) {
+               err = BTRFS_UTIL_ERROR_NO_MEMORY;
+               goto out_iter;
+       }
+
+       iter->cur_path_capacity = 256;
+       iter->cur_path = malloc(iter->cur_path_capacity);
+       if (!iter->cur_path) {
+               err = BTRFS_UTIL_ERROR_NO_MEMORY;
+               goto out_search_stack;
+       }
+
+       err = append_to_search_stack(iter, top, 0);
+       if (err)
+               goto out_cur_path;
+
+       *ret = iter;
+
+       return BTRFS_UTIL_OK;
+
+out_cur_path:
+       free(iter->cur_path);
+out_search_stack:
+       free(iter->search_stack);
+out_iter:
+       free(iter);
+       return err;
+}
+
+static enum btrfs_util_error snapshot_subvolume_children(int fd, int parent_fd,
+                                                        const char *name,
+                                                        uint64_t *async_transid)
+{
+       struct btrfs_util_subvolume_iterator *iter;
+       enum btrfs_util_error err;
+       int dstfd;
+
+       dstfd = openat(parent_fd, name, O_RDONLY);
+       if (dstfd == -1)
+               return BTRFS_UTIL_ERROR_OPEN_FAILED;
+
+       err = btrfs_util_create_subvolume_iterator_fd(fd, 0, 0, &iter);
+       if (err)
+               goto out;
+
+       for (;;) {
+               char child_name[BTRFS_SUBVOL_NAME_MAX + 1];
+               char *child_path;
+               int child_fd, new_parent_fd;
+               uint64_t tmp_transid;
+
+               err = btrfs_util_subvolume_iterator_next(iter, &child_path,
+                                                        NULL);
+               if (err) {
+                       if (err == BTRFS_UTIL_ERROR_STOP_ITERATION)
+                               err = BTRFS_UTIL_OK;
+                       break;
+               }
+
+               /* Remove the placeholder directory. */
+               if (unlinkat(dstfd, child_path, AT_REMOVEDIR) == -1) {
+                       free(child_path);
+                       err = BTRFS_UTIL_ERROR_RMDIR_FAILED;
+                       break;
+               }
+
+               child_fd = openat(fd, child_path, O_RDONLY);
+               if (child_fd == -1) {
+                       free(child_path);
+                       err = BTRFS_UTIL_ERROR_OPEN_FAILED;
+                       break;
+               }
+
+               err = openat_parent_and_name(dstfd, child_path, child_name,
+                                            sizeof(child_name),
+                                            &new_parent_fd);
+               free(child_path);
+               if (err) {
+                       SAVE_ERRNO_AND_CLOSE(child_fd);
+                       break;
+               }
+
+               err = btrfs_util_create_snapshot_fd2(child_fd, new_parent_fd,
+                                                    child_name, 0,
+                                                    async_transid ? &tmp_transid : NULL,
+                                                    NULL);
+               SAVE_ERRNO_AND_CLOSE(child_fd);
+               SAVE_ERRNO_AND_CLOSE(new_parent_fd);
+               if (err)
+                       break;
+               if (async_transid && tmp_transid > *async_transid)
+                       *async_transid = tmp_transid;
+       }
+
+       btrfs_util_destroy_subvolume_iterator(iter);
+out:
+       SAVE_ERRNO_AND_CLOSE(dstfd);
+       return err;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_create_snapshot(const char *source,
+                                                       const char *path,
+                                                       int flags,
+                                                       uint64_t *async_transid,
+                                                       struct btrfs_util_qgroup_inherit *qgroup_inherit)
+{
+       enum btrfs_util_error err;
+       int fd;
+
+       fd = open(source, O_RDONLY);
+       if (fd == -1)
+               return BTRFS_UTIL_ERROR_OPEN_FAILED;
+
+       err = btrfs_util_create_snapshot_fd(fd, path, flags, async_transid,
+                                           qgroup_inherit);
+       SAVE_ERRNO_AND_CLOSE(fd);
+       return err;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_create_snapshot_fd(int fd,
+                                                          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_snapshot_fd2(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_snapshot_fd2(int 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 = {.fd = fd};
+       enum btrfs_util_error err;
+       size_t len;
+       int ret;
+
+       if ((flags & ~BTRFS_UTIL_CREATE_SNAPSHOT_MASK) ||
+           ((flags & BTRFS_UTIL_CREATE_SNAPSHOT_READ_ONLY) &&
+            (flags & BTRFS_UTIL_CREATE_SNAPSHOT_RECURSIVE))) {
+               errno = EINVAL;
+               return BTRFS_UTIL_ERROR_INVALID_ARGUMENT;
+       }
+
+       if (flags & BTRFS_UTIL_CREATE_SNAPSHOT_READ_ONLY)
+               args.flags |= BTRFS_SUBVOL_RDONLY;
+       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_SNAP_CREATE_V2, &args);
+       if (ret == -1)
+               return BTRFS_UTIL_ERROR_SUBVOL_CREATE_FAILED;
+
+       if (async_transid)
+               *async_transid = args.transid;
+
+       if (flags & BTRFS_UTIL_CREATE_SNAPSHOT_RECURSIVE) {
+               err = snapshot_subvolume_children(fd, parent_fd, name,
+                                                 async_transid);
+               if (err)
+                       return err;
+       }
+
+       return BTRFS_UTIL_OK;
+}
+
+static enum btrfs_util_error delete_subvolume_children(int parent_fd,
+                                                      const char *name)
+{
+       struct btrfs_util_subvolume_iterator *iter;
+       enum btrfs_util_error err;
+       int fd;
+
+       fd = openat(parent_fd, name, O_RDONLY);
+       if (fd == -1)
+               return BTRFS_UTIL_ERROR_OPEN_FAILED;
+
+       err = btrfs_util_create_subvolume_iterator_fd(fd, 0,
+                                                     BTRFS_UTIL_SUBVOLUME_ITERATOR_POST_ORDER,
+                                                     &iter);
+       if (err)
+               goto out;
+
+       for (;;) {
+               char child_name[BTRFS_PATH_NAME_MAX + 1];
+               char *child_path;
+               int child_parent_fd;
+
+               err = btrfs_util_subvolume_iterator_next(iter, &child_path,
+                                                        NULL);
+               if (err) {
+                       if (err == BTRFS_UTIL_ERROR_STOP_ITERATION)
+                               err = BTRFS_UTIL_OK;
+                       break;
+               }
+
+               err = openat_parent_and_name(fd, child_path, child_name,
+                                            sizeof(child_name),
+                                            &child_parent_fd);
+               free(child_path);
+               if (err)
+                       break;
+
+               err = btrfs_util_delete_subvolume_fd(child_parent_fd,
+                                                    child_name, 0);
+               SAVE_ERRNO_AND_CLOSE(child_parent_fd);
+               if (err)
+                       break;
+       }
+
+       btrfs_util_destroy_subvolume_iterator(iter);
+out:
+       SAVE_ERRNO_AND_CLOSE(fd);
+       return err;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_delete_subvolume(const char *path,
+                                                        int flags)
+{
+       char name[BTRFS_PATH_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_delete_subvolume_fd(parent_fd, name, flags);
+       SAVE_ERRNO_AND_CLOSE(parent_fd);
+       return err;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_delete_subvolume_fd(int parent_fd,
+                                                           const char *name,
+                                                           int flags)
+{
+       struct btrfs_ioctl_vol_args args = {};
+       enum btrfs_util_error err;
+       size_t len;
+       int ret;
+
+       if (flags & ~BTRFS_UTIL_DELETE_SUBVOLUME_MASK) {
+               errno = EINVAL;
+               return BTRFS_UTIL_ERROR_INVALID_ARGUMENT;
+       }
+
+       if (flags & BTRFS_UTIL_DELETE_SUBVOLUME_RECURSIVE) {
+               err = delete_subvolume_children(parent_fd, name);
+               if (err)
+                       return err;
+       }
+
+       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_SNAP_DESTROY, &args);
+       if (ret == -1)
+               return BTRFS_UTIL_ERROR_SNAP_DESTROY_FAILED;
+
+       return BTRFS_UTIL_OK;
+}
+
+PUBLIC void btrfs_util_destroy_subvolume_iterator(struct btrfs_util_subvolume_iterator *iter)
+{
+       if (iter) {
+               free(iter->cur_path);
+               free(iter->search_stack);
+               if (iter->flags & BTRFS_UTIL_SUBVOLUME_ITERATOR_CLOSE_FD)
+                       SAVE_ERRNO_AND_CLOSE(iter->fd);
+               free(iter);
+       }
+}
+
+PUBLIC int btrfs_util_subvolume_iterator_fd(const struct btrfs_util_subvolume_iterator *iter)
+{
+       return iter->fd;
+}
+
+static struct search_stack_entry *top_search_stack_entry(struct btrfs_util_subvolume_iterator *iter)
+{
+       return &iter->search_stack[iter->search_stack_len - 1];
+}
+
+static enum btrfs_util_error build_subvol_path(struct btrfs_util_subvolume_iterator *iter,
+                                              const struct btrfs_ioctl_search_header *header,
+                                              const struct btrfs_root_ref *ref,
+                                              const char *name,
+                                              size_t *path_len_ret)
+{
+       struct btrfs_ioctl_ino_lookup_args lookup = {
+               .treeid = header->objectid,
+               .objectid = le64_to_cpu(ref->dirid),
+       };
+       struct search_stack_entry *top = top_search_stack_entry(iter);
+       size_t dir_len, name_len, path_len;
+       char *p;
+       int ret;
+
+       ret = ioctl(iter->fd, BTRFS_IOC_INO_LOOKUP, &lookup);
+       if (ret == -1)
+               return BTRFS_UTIL_ERROR_INO_LOOKUP_FAILED;
+
+       dir_len = strlen(lookup.name);
+       name_len = le16_to_cpu(ref->name_len);
+
+       path_len = top->path_len;
+       /*
+        * We need a joining slash if we have a current path and a subdirectory.
+        */
+       if (top->path_len && dir_len)
+               path_len++;
+       path_len += dir_len;
+       /*
+        * We need another joining slash if we have a current path and a name,
+        * but not if we have a subdirectory, because the lookup ioctl includes
+        * a trailing slash.
+        */
+       if (top->path_len && !dir_len && name_len)
+               path_len++;
+       path_len += name_len;
+
+       if (path_len > iter->cur_path_capacity) {
+               char *tmp = realloc(iter->cur_path, path_len);
+
+               if (!tmp)
+                       return BTRFS_UTIL_ERROR_NO_MEMORY;
+               iter->cur_path = tmp;
+               iter->cur_path_capacity = path_len;
+       }
+
+       p = iter->cur_path + top->path_len;
+       if (top->path_len && dir_len)
+               *p++ = '/';
+       memcpy(p, lookup.name, dir_len);
+       p += dir_len;
+       if (top->path_len && !dir_len && name_len)
+               *p++ = '/';
+       memcpy(p, name, name_len);
+       p += name_len;
+
+       *path_len_ret = path_len;
+
+       return BTRFS_UTIL_OK;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_subvolume_iterator_next(struct btrfs_util_subvolume_iterator *iter,
+                                                               char **path_ret,
+                                                               uint64_t *id_ret)
+{
+       struct search_stack_entry *top;
+       const struct btrfs_ioctl_search_header *header;
+       const struct btrfs_root_ref *ref;
+       const char *name;
+       enum btrfs_util_error err;
+       size_t path_len;
+       int ret;
+
+       for (;;) {
+               for (;;) {
+                       if (iter->search_stack_len == 0)
+                               return BTRFS_UTIL_ERROR_STOP_ITERATION;
+
+                       top = top_search_stack_entry(iter);
+                       if (top->items_pos < top->search.key.nr_items) {
+                               break;
+                       } else {
+                               top->search.key.nr_items = 4096;
+                               ret = ioctl(iter->fd, BTRFS_IOC_TREE_SEARCH, &top->search);
+                               if (ret == -1)
+                                       return BTRFS_UTIL_ERROR_SEARCH_FAILED;
+                               top->items_pos = 0;
+                               top->buf_off = 0;
+
+                               if (top->search.key.nr_items == 0) {
+                                       iter->search_stack_len--;
+                                       if ((iter->flags & BTRFS_UTIL_SUBVOLUME_ITERATOR_POST_ORDER) &&
+                                           iter->search_stack_len)
+                                               goto out;
+                               }
+                       }
+               }
+
+               header = (struct btrfs_ioctl_search_header *)(top->search.buf + top->buf_off);
+
+               top->items_pos++;
+               top->buf_off += sizeof(*header) + header->len;
+               top->search.key.min_offset = header->offset + 1;
+
+               /* This shouldn't happen, but handle it just in case. */
+               if (header->type != BTRFS_ROOT_REF_KEY)
+                       continue;
+
+               ref = (struct btrfs_root_ref *)(header + 1);
+               name = (const char *)(ref + 1);
+               err = build_subvol_path(iter, header, ref, name, &path_len);
+               if (err)
+                       return err;
+
+               err = append_to_search_stack(iter, header->offset, path_len);
+               if (err)
+                       return err;
+
+               if (!(iter->flags & BTRFS_UTIL_SUBVOLUME_ITERATOR_POST_ORDER)) {
+                       top = top_search_stack_entry(iter);
+                       goto out;
+               }
+       }
+
+out:
+       if (path_ret) {
+               *path_ret = malloc(top->path_len + 1);
+               if (!*path_ret)
+                       return BTRFS_UTIL_ERROR_NO_MEMORY;
+               memcpy(*path_ret, iter->cur_path, top->path_len);
+               (*path_ret)[top->path_len] = '\0';
+       }
+       if (id_ret)
+               *id_ret = top->search.key.min_objectid;
+       return BTRFS_UTIL_OK;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_subvolume_iterator_next_info(struct btrfs_util_subvolume_iterator *iter,
+                                                                    char **path_ret,
+                                                                    struct btrfs_util_subvolume_info *subvol)
+{
+       enum btrfs_util_error err;
+       uint64_t id;
+
+       err = btrfs_util_subvolume_iterator_next(iter, path_ret, &id);
+       if (err)
+               return err;
+
+       return btrfs_util_subvolume_info_fd(iter->fd, id, subvol);
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_deleted_subvolumes(const char *path,
+                                                          uint64_t **ids,
+                                                          size_t *n)
+{
+       enum btrfs_util_error err;
+       int fd;
+
+       fd = open(path, O_RDONLY);
+       if (fd == -1)
+               return BTRFS_UTIL_ERROR_OPEN_FAILED;
+
+       err = btrfs_util_deleted_subvolumes_fd(fd, ids, n);
+       SAVE_ERRNO_AND_CLOSE(fd);
+       return err;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_deleted_subvolumes_fd(int fd,
+                                                             uint64_t **ids,
+                                                             size_t *n)
+{
+       size_t capacity = 0;
+       struct btrfs_ioctl_search_args search = {
+               .key = {
+                       .tree_id = BTRFS_ROOT_TREE_OBJECTID,
+                       .min_objectid = BTRFS_ORPHAN_OBJECTID,
+                       .max_objectid = BTRFS_ORPHAN_OBJECTID,
+                       .min_type = BTRFS_ORPHAN_ITEM_KEY,
+                       .max_type = BTRFS_ORPHAN_ITEM_KEY,
+                       .min_offset = 0,
+                       .max_offset = UINT64_MAX,
+                       .min_transid = 0,
+                       .max_transid = UINT64_MAX,
+                       .nr_items = 0,
+               },
+       };
+       enum btrfs_util_error err;
+       size_t items_pos = 0, buf_off = 0;
+       int ret;
+
+       *ids = NULL;
+       *n = 0;
+       for (;;) {
+               const struct btrfs_ioctl_search_header *header;
+
+               if (items_pos >= search.key.nr_items) {
+                       search.key.nr_items = 4096;
+                       ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &search);
+                       if (ret == -1) {
+                               err = BTRFS_UTIL_ERROR_SEARCH_FAILED;
+                               goto out;
+                       }
+                       items_pos = 0;
+                       buf_off = 0;
+
+                       if (search.key.nr_items == 0)
+                               break;
+               }
+
+               header = (struct btrfs_ioctl_search_header *)(search.buf + buf_off);
+
+               /*
+                * The orphan item might be for a free space cache inode, so
+                * check if there's a matching root item.
+                */
+               err = btrfs_util_subvolume_info_fd(fd, header->offset, NULL);
+               if (!err) {
+                       if (*n >= capacity) {
+                               size_t new_capacity;
+                               uint64_t *new_ids;
+
+                               new_capacity = capacity ? capacity * 2 : 1;
+                               new_ids = reallocarray(*ids, new_capacity,
+                                                      sizeof(**ids));
+                               if (!new_ids) {
+                                       err = BTRFS_UTIL_ERROR_NO_MEMORY;
+                                       goto out;
+                               }
+
+                               *ids = new_ids;
+                               capacity = new_capacity;
+                       }
+                       (*ids)[(*n)++] = header->offset;
+               } else if (err != BTRFS_UTIL_ERROR_SUBVOLUME_NOT_FOUND) {
+                       goto out;
+               }
+
+               items_pos++;
+               buf_off += sizeof(*header) + header->len;
+               search.key.min_offset = header->offset + 1;
+       }
+
+       err = BTRFS_UTIL_OK;
+out:
+       if (err) {
+               free(*ids);
+               *ids = NULL;
+               *n = 0;
+       }
+       return err;
+}