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@xxxxxxxxxxxxxx>
---
*Note*
This is just a temporary workaround to fix this problem in order to
make users happy, because a new ioctl or sysfs interface to handle this
problem needs more discussions and efforts. After the work implemented
and accepted, we could drop this.
---
utils.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 74 insertions(+)
diff --git a/utils.c b/utils.c
index 9bcc1a0..a6dcb8a 100644
--- a/utils.c
+++ b/utils.c
@@ -1781,6 +1781,73 @@ int get_device_info(int fd, u64 devid,
return ret ? -errno : 0;
}
+u64 find_max_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);
+}
+
+int correct_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_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_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.
@@ -1860,6 +1927,13 @@ 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 = correct_fs_info(fd, fi_args);
+ if (ret)
+ goto out;
}
if (!fi_args->num_devices)
--
1.8.1.4
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