On Tue, Sep 24, 2002 at 01:21:10PM +0400, Oleg Drokin wrote:
> Hello!
>
...
>
> > I would suggest replacing the '!=' with a '<' in the while loop and
> > adding a sanity check afterwards.
>
> What if overheated CPU will cause a bitflip exactly after such checks?
> You cannot protect against broken hardware. Such problems should be
> fixed by fsck.
Disk errors are common. Software can also flip that bit.
But I agree that it shouldn't be something that commonly happens, and I
suppose it is acceptable for a filesystem to barf if it has been
corrupted by malicious software.
>
> > As I see it, the ReiserFS journal has the same problems as jbd wrt. to
> > atomicity of write operations of indexes. Please see my recent mail
> > about the jbd problems.
>
> journal header in reiserfs only occupies first 20 bytes of the block,
> since this fells within 1st 512 bytes hardware sector, it will be written
> atomically, I presume.
You presume wrong.
I posted to LKML about a month ago with some questions regarding exactly
this issue. I had a disk that worked on 128 byte atomic writes - a
standard IDE disk.
The conclusion was something like "we know jack about the disk's
internal logic" so we need consistency measures instead of relying on
anything from the disk.
-- ................................................................ : jakob@unthought.net : And I see the elder races, : :.........................: putrid forms of man : : Jakob Østergaard : See him rise and claim the earth, : : OZ9ABN : his downfall is at hand. : :.........................:............{Konkhra}...............: - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Mon Sep 30 2002 - 22:00:18 EST