On Wed, Mar 13, 2019 at 06:03:42PM +0800, Zorro Lang wrote: > > > + io_prep_pwrite(&iocb1, fd, buf, buf_size/2, \ > > > + startoff + bytes + 0*buf_size/2); > > > + io_prep_pwrite(&iocb2, fd, buf, buf_size/2, \ > > > + startoff + bytes + 1*buf_size/2); > > > > This is just a little bit confusing. I'd expect the write size to be a > > buffer size, not buffer size/2. Is there a reason you wanted to do it > > this way ? > > The buf is used for below pread() too. We write twice separately at here, > so write buf/2 each time. Then read whole buf size once. Sure, but from the persective of someone using this thing I'd expect the buf_size to be the size of the write. I do not think it matters too much as long as you can explain it in the description of the program. > > > > > Also, do we need the size_KB ? I'd expect it would just do two writes. > > One starting in one block before i_size and ending before i_size but in > > the same block as i_size and the second starting beyond i_size but still > > in the same block as i_size. > > > > I guess it does not hurt to be able to specify size_KB, but I wonder > > what was your reason to include it ? > > > > Moreover I think it would be interesting to also allow the second write > > not to be aligned with i_size but still be in the same block. Something > > like: > > > > io_prep_pwrite(&iocb1, fd, buf, buf_size, startoff); > > io_prep_pwrite(&iocb2, fd, buf, buf_size, startoff + buf_size + shift); > > > > where "shift" (or whatever you want to call it) can be user specified. > > Hmmm, I think I can do that in below generic/999, by provide different arguments > to $AIO_TEST. Looking at the code I do not think you can, but maybe I am wrong. > > > +localfile=$TEST_DIR/tst-aio-dio-testfile > > > +diosize=`_min_dio_alignment $TEST_DEV` > > > +pagesize=`src/feature -s` > > > +bufsize=$((pagesize * 2)) > > > +filesize=$((bufsize * 3 / 1024)) > > > + > > > +# Need smaller logical block size to do non-page-aligned test > > > +if [ $diosize -ge $pagesize ];then > > > + _notrun "Need device logical block size($diosize) < page size($pagesize)" > > > +fi > > > + > > > +rm -rf $localfile 2>/dev/null > > > +# page-aligned aiodio write verification at first > > > +$AIO_TEST -s $((bufsize * 10)) -b $bufsize $localfile > > > + > > > +# non-page-aligned aiodio write verification > > > +i=0 > > > +while [ $((diosize * i)) -lt $bufsize ];do > > > + truncsize=$((diosize * i++)) > > > + # non-page-aligned AIO write on different i_size file > > > + $AIO_TEST -s $filesize -b $bufsize -o $diosize -t $truncsize $localfile > > > > Why are we starting the write at diosize when truncsize is getting > > bigger and bigger and filesize remains the same. . Is filesize > > necessary ? > > The filesize is just used to decide how many times $AIO_TEST will write, then exit. It's > not related with this bug, just a limit condition. > > That .c program is not only to reproduce that ext4 bug. It can be used to do direct AIO > write and verify. Then the generic/999 is used to cover that ext4 bug, and maybe cover > more operations. Fair enough, just please decribe what the program is good for and what it can do. Currently it's not entirely clear. Thanks! -Lukas > > Thanks, > Zorro
