wic/filemap: If FIGETBSZ iotctl fail, failback to os.stat

Some file systems don't support fetching the block size (notably the
file system Docker uses for containers), so if iotctl() fail, try to use
failback via os.stat() to get block size.

(From OE-Core rev: 996013b4e5d3cd1c054e87539ac1a8d95581a87f)

Signed-off-by: Kalle lampila <kalle.lampila@lempea.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit e219f5175177a640dd62833082ea19adc1c13d42)
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/scripts/lib/wic/filemap.py b/scripts/lib/wic/filemap.py
index a3919fbcad..c53147c2f1 100644
--- a/scripts/lib/wic/filemap.py
+++ b/scripts/lib/wic/filemap.py
@@ -34,9 +34,11 @@ def get_block_size(file_obj):
     # the FIGETBSZ ioctl (number 2).
     try:
         binary_data = fcntl.ioctl(file_obj, 2, struct.pack('I', 0))
+        bsize = struct.unpack('I', binary_data)[0]
     except OSError:
-        raise IOError("Unable to determine block size")
-    bsize = struct.unpack('I', binary_data)[0]
+        bsize = None
+
+    # If ioctl causes OSError or give bsize to zero failback to os.fstat
     if not bsize:
         import os
         stat = os.fstat(file_obj.fileno())