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Re: [PATCH] ufs: Fix build errors on 32 bit machines




On 06/17/2017 11:23 AM, Al Viro wrote:
On Sat, Jun 17, 2017 at 10:35:13AM -0700, Guenter Roeck wrote:
Various 32 builds fail with error messages such as

ERROR: "__udivdi3" [fs/ufs/ufs.ko] undefined!

due to a variable type change from 32 bit to 64 bit.

Actually, that's not the only problem in that place.  The breakage
came in 2.4.14.7; the critical part was this:
             default:
-               usb1->fs_optim = SWAB32(UFS_OPTTIME);
+               usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
case UFS_OPTTIME:
                 request = uspi->s_fpb;
-               if (SWAB32(usb1->fs_cstotal.cs_nffree) < uspi->s_dsize *
+               if (fs32_to_cpu(sb, usb1->fs_cstotal.cs_nffree) < uspi->s_dsize *
                     (uspi->s_minfree - 2) / 100)
                         break;
-               usb1->fs_optim = SWAB32(UFS_OPTSPACE);
+               usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
                 break;

See the problem?  Instead of hysteresis loop flipping between optspace and opttime
allocation policies, it *never* switches out of opttime.

Yes. Nice catch.

That came in

commit 6293d56ca18db9ed322b2a5550ac7b27bd538cff
Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Date:   Mon Feb 4 20:33:51 2002 -0800

     v2.4.14.6 -> v2.4.14.7
- Jeff Garzik: network driver updates
       - Christoph Hellwig: UFS filesystem byteorder cleanups
       - me: modified Andrea VM page allocator tuning

so probably a typo in Christoph's patches, missed by everyone at the time.

And I would prefer to have the nffree levels at which we switch back and
forth precalculated at mount time.  I'll send a fix (along with those
for the last remaining xfstests failures) later today.


Agreed, but wouldn't it be more important to get the code to compile for now ?
After all, optimizing the calculation is an enhancement, not a bug fix.

Thanks,
Guenter