Messages in this thread | | | Date | Tue, 24 Sep 2002 11:27:20 +0200 | From | Jakob Oestergaard <> | Subject | Re: ReiserFS buglet |
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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.
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