btrfs-progs: fix wrong num_devices for btrfs fi show with seed devices

The @fi_args->num_devices in @get_fs_info() does not include seed devices.
We could just correct it by searching the chunk tree and count how
many dev_items there are in total which includes seed devices.

Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>

diff --git a/utils.c b/utils.c
index 16b10e0..8885669 100644 (file)
--- a/utils.c
+++ b/utils.c
@@ -1815,6 +1815,75 @@ int get_device_info(int fd, u64 devid,
        return ret ? -errno : 0;
 }
 
+static u64 find_max_device_id(struct btrfs_ioctl_search_args *search_args,
+                             int nr_items)
+{
+       struct btrfs_dev_item *dev_item;
+       char *buf = search_args->buf;
+
+       buf += (nr_items - 1) * (sizeof(struct btrfs_ioctl_search_header)
+                                      + sizeof(struct btrfs_dev_item));
+       buf += sizeof(struct btrfs_ioctl_search_header);
+
+       dev_item = (struct btrfs_dev_item *)buf;
+
+       return btrfs_stack_device_id(dev_item);
+}
+
+static int search_chunk_tree_for_fs_info(int fd,
+                               struct btrfs_ioctl_fs_info_args *fi_args)
+{
+       int ret;
+       int max_items;
+       u64 start_devid = 1;
+       struct btrfs_ioctl_search_args search_args;
+       struct btrfs_ioctl_search_key *search_key = &search_args.key;
+
+       fi_args->num_devices = 0;
+
+       max_items = BTRFS_SEARCH_ARGS_BUFSIZE
+              / (sizeof(struct btrfs_ioctl_search_header)
+                              + sizeof(struct btrfs_dev_item));
+
+       search_key->tree_id = BTRFS_CHUNK_TREE_OBJECTID;
+       search_key->min_objectid = BTRFS_DEV_ITEMS_OBJECTID;
+       search_key->max_objectid = BTRFS_DEV_ITEMS_OBJECTID;
+       search_key->min_type = BTRFS_DEV_ITEM_KEY;
+       search_key->max_type = BTRFS_DEV_ITEM_KEY;
+       search_key->min_transid = 0;
+       search_key->max_transid = (u64)-1;
+       search_key->nr_items = max_items;
+       search_key->max_offset = (u64)-1;
+
+again:
+       search_key->min_offset = start_devid;
+
+       ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &search_args);
+       if (ret < 0)
+               return -errno;
+
+       fi_args->num_devices += (u64)search_key->nr_items;
+
+       if (search_key->nr_items == max_items) {
+               start_devid = find_max_device_id(&search_args,
+                                       search_key->nr_items) + 1;
+               goto again;
+       }
+
+       /* get the lastest max_id to stay consistent with the num_devices */
+       if (search_key->nr_items == 0)
+               /*
+                * last tree_search returns an empty buf, use the devid of
+                * the last dev_item of the previous tree_search
+                */
+               fi_args->max_id = start_devid - 1;
+       else
+               fi_args->max_id = find_max_device_id(&search_args,
+                                               search_key->nr_items);
+
+       return 0;
+}
+
 /*
  * For a given path, fill in the ioctl fs_ and info_ args.
  * If the path is a btrfs mountpoint, fill info for all devices.
@@ -1894,6 +1963,13 @@ int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args,
                        ret = -errno;
                        goto out;
                }
+
+               /*
+                * The fs_args->num_devices does not include seed devices
+                */
+               ret = search_chunk_tree_for_fs_info(fd, fi_args);
+               if (ret)
+                       goto out;
        }
 
        if (!fi_args->num_devices)