diff options
| -rw-r--r-- | util-linux/volume_id/btrfs.c | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/util-linux/volume_id/btrfs.c b/util-linux/volume_id/btrfs.c index 53bac7438..777b80923 100644 --- a/util-linux/volume_id/btrfs.c +++ b/util-linux/volume_id/btrfs.c @@ -80,19 +80,26 @@ struct btrfs_super_block { int FAST_FUNC volume_id_probe_btrfs(struct volume_id *id /*,uint64_t off*/) { -#define off ((uint64_t) (64 * 1024)) + // btrfs has superblocks at 64K, 64M and 256G + // minimum btrfs size is 256M + // so we never step out the device if we analyze + // the first and the second superblocks struct btrfs_super_block *sb; + unsigned off = 64; - dbg("btrfs: probing at offset 0x%llx", (unsigned long long) off); + while (off < 64*1024*1024) { + off *= 1024; + dbg("btrfs: probing at offset 0x%x", off); - sb = volume_id_get_buffer(id, off, sizeof(*sb)); - if (sb == NULL) - return -1; + sb = volume_id_get_buffer(id, off, sizeof(*sb)); + if (sb == NULL) + return -1; - if (memcmp(sb->magic, BTRFS_MAGIC, 8) != 0) - return -1; + if (memcmp(sb->magic, BTRFS_MAGIC, 8) != 0) + return -1; + } - // N.B.: btrfs supports 256-byte labels + // N.B.: btrfs natively supports 256 (>VOLUME_ID_LABEL_SIZE) size labels volume_id_set_label_string(id, sb->label, VOLUME_ID_LABEL_SIZE); volume_id_set_uuid(id, sb->fsid, UUID_DCE); |