I have a device /dev/sdb1 and let's trace the block request by blktrace $ sudo blktrace -d /dev/sdb1
When I write 4KB using dd $ sudo dd if=/dev/zero of=/dev/sdb1 oflag=direct bs=4k count=1 The block trace (after blkparsed) is write request as expected 8,17 2 2 0.000003171 5930 Q WS 2048 + 8 [dd] followed by a unexpected read from systemd-udevd 8,17 7 2 0.001755563 5931 Q R 2048 + 8 [systemd-udevd] My first question is what is: this read request? And I want to stop the read request because it makes it difficult to test kernel code. So the second question is: how can I stop the read request? Actually I found this behavior when I test my module https://github.com/akiradeveloper/dm-writeboost Since I need to create/remove devices during the tests, there is no choice to stop udev.service. FYI, I am using Debian 9.2 Thanks, - Akira _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
