[LTP] [PATCH v3] Use real FS block size in fallocate05

[Cyril Hrubis]

Hi!
> > Why realloc()? Each filesystem is tested in separately forked process so
> > buf can't be anything but NULL here.
> > 
> > So this should just simply be SAFE_MALLOC() and this piece of code, the
> > part that gets the blocksize and allocates the buffer should be moved
> > into the test setup() function that is executed also once per
> > filesystem. And the free should be in the test cleanup().
> > 
> > That way we would allocate the buffer only once if the test was executed
> > with -i option.
> 
> Where is this control flow documented? When some behavior is not
> documented, I assume it may change without notice and write my code so
> that it will work in every case.

Unfortunately at the moment only in the lib/tst_test.c source code.

I want to write down a design document for the library, that would
explain the more complicated parts and decisions, but I'm not sure when
I will get to that.

> >> -	tst_res(TPASS | TERRNO, "fallocate() on full FS");
> >> +	for (tmp = extsize; tmp > 0; tmp -= TST_RET) {
> >> +		TEST(write(fd, buf, MIN(bufsize, tmp)));
> >>  
> >> -	ret = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0, FALLOCATE_SIZE);
> >> -	if (ret == -1) {
> >> -		if (errno == EOPNOTSUPP)
> >> +		if (TST_RET <= 0)
> >> +			tst_brk(TFAIL | TTERRNO, "write() failed unexpectedly");
> > 
> > tst_brk(TFAIL, is not allowed at the moment, see:
> > 
> > https://github.com/linux-test-project/ltp/issues/462
> > 
> > The only current solution is to tst_res() + return
> > 
> > Also shouldn't we check for the write size here as well?
> 
> I'll fix the tst_brk().
> 
> The code above will either fill the extra allocated space to the last
> byte, or hit the tst_brk(). No other result is possible. I don't want to
> pedantically check for short writes because we're not testing write() here.
> 
> I'll implement the rest of your suggestions and resubmit when we get a
> reply from Btrfs devs.

Ok, thanks.

-- 
Cyril Hrubis
chrubis@suse.cz