On Thu, 8 Aug 2013, Chaitra Bhat wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA512 > > Hi Mikulas, > > I get 'Invalid argument' with 'iflag=direct' option when I try to read > from a verity device using dd. If you use iflag=direct, block size and offset must be aligned on physical block size boundary (usually 4k). If they are not aligned, you get invalid argument error. > Before I read from the device, I also did 'echo 3 > > /proc/sys/vm/drop_caches' to make sure caches are dropped. If the filesystem is mounted, it doesn't drop some buffers (those that are used by the filesystem). Unmount the filesystem first. > But as I said before, some locations always fail with I/O error when > read and others don't. If you still get misbehavior, even if you bypass the cache with iflag=direct or with filesystem unmount, create a script that reproduces it and send it to us. > Regards, > Chaitra Mikulas -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
