Messages in this thread | | | Date | Tue, 20 Mar 2001 20:29:37 +0100 (CET) | From | Geert Uytterhoeven <> | Subject | Re: st corruption with 2.4.3-pre4 |
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On Tue, 20 Mar 2001, Geert Uytterhoeven wrote: > On Mon, 19 Mar 2001, Jeff Garzik wrote: > > Is the corruption reproducible? If so, does the corruption go away if > > Yes, it is reproducible. In all my tests, I tarred 16 files of 16 MB each to > tape (I used a new one). > - test 1: 4 files with failed md5sum (no further investigation on type of > corruption) > - test 2: 7 files with failed md5sum, 7 blocks of 32 consecutive bytes were > corrupted, all starting at an offset of the form 32*x+1. > - test 3: 7 files with failed md5sum, 7 blocks of 32 consecutive bytes were > corrupted, all starting at an offset of the form 32*x+1. > > The files seem to be corrupted during writing only, as reading always gives the > exact same (corrupted) data back. > > Copying files from the disk on the MESH to a disk on the Sym53c875 (which also > has the tape drive) shows no corruption.
I did some more tests: - The problem also occurs when tarring up files from a disk on the Sym53c875. - The corrupted data always occurs at offset 32*x (the `+1' above was caused by hexdump, starting counting at 1). - The 32 bytes of corrupted data at offset 32*x are always a copy of the data at offset 32*x-10240. - Since 10240 is the default blocksize of tar (bug in tar?), I made a tarball on disk instead of on tape, but no corruption. - 32 is the size of a cacheline on PPC. Is there a missing cacheflush somewhere in the Sym53c875 driver? But then it should happen on disk as well?
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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