On 2/4/22 2:22 AM, Milan Broz wrote: > Hi Jens, > > It seems that there is a regression in direct-io over loop for partial > direct-io reads (or perhaps even for other situations). > > If I run this code (loop over 6M file, dd direct-io read with 4M blocks) > > IMG=tst.img > LOOP=/dev/loop66 > > truncate -s 6M $IMG > losetup $LOOP $IMG > dd if=$LOOP of=/dev/null bs=4M iflag=direct > losetup -d $LOOP > > > on older kernel (<=5.16) it reads the whole file > 6291456 bytes (6.3 MB, 6.0 MiB) copied, 0.201591 s, 31.2 MB/s > > > while on 5.17-rc (tested on today/s Linus' git) it reads only the full blocks: > 4194304 bytes (4.2 MB, 4.0 MiB) copied, 0.201904 s, 20.8 MB/s > > No error reported, exit code is 0. Can you try: https://git.kernel.dk/cgit/linux-block/commit/?h=block-5.17&id=3e1f941dd9f33776b3df4e30f741fe445ff773f3 -- Jens Axboe
