Messages in this thread |  | | Date | Sat, 22 Sep 2001 06:00:43 -0400 (EDT) | From | foner-reiserfs@media ... | Subject | ReiserFS data corruption in very simple configuration |
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[Please CC me on any replies; I'm not on linux-kernel.]
The ReiserFS that comes with both Mandrake 7.2 and 8.0 has demonstrated a serious data corruption problem, and I'd like to know (a) if anyone else has seen this, (b) how to avoid it, and (c) how to determine how badly I've been bitten.
My configuration in each case has been an AMD CPU running ReiserFS exactly as configured "out of the box" by running the Mandrake 7.2 or 8.0 installation CD and opting to run ReiserFS instead of the default. This is a uniprocessor machine with one IDE 80GB Maxtor disk---no RAID or anything fancy like that. The hardware itself is rock solid and has never demonstrated any faults at all. (MDK 8.0 appears to use RSFS 3.6.25; I'm not longer running MDK 7.2, so I can't check that.) The machine had barely been used before each corruption problem; I'm not running some strange root-priv stuff, and each time, the FS hadn't had more than a few minutes to a few hours of use since being created.
In each case, I've gotten in trouble by editing my XF86Config-4 file, guessing wrong on a modeline, hanging X (blank gray screen & no response to anything), and being forced to hit the reset button because nothing else worked. Under 7.2, I discovered that my XF86Config-4 file suddenly had a block of nulls in it. That time, I thought I must have been hallucinating, but I ran a background job to sync the filesystem every second while continuing to debug the X problems, and didn't see the corruption again.
Now, I was just bitten by the -same- behavior under MDK 8.0. After accidentally hanging X, I waited a few seconds just in case a sync was pending, hit reset, and had all sorts of lossage: (1) Parts of the XF86Conf-4 file had lines garbled, e.g., sections of the file had apparently been rearranged. (2) /var/log/XFree86.0.log was truncated, and maybe garbled. (2) Logging in as root was fine, but then logging in as myself I got "Last login: <4-5 lines of my XFree86.0.log file (!)>" instead of a date! Logging in again gave me the proper last-login time, but clearly wtmp or something else had gotten stepped on in some weird way. Obviously, the behavior I saw once under MDK 7.2 was no hallucination or accidental yank in Emacs.
I thought the whole point of a journalling file system was to -prevent- corruption due to an unexpected failure! This seems to be -far- worse than a normal filesystem---ext2fs would at least choke and force fsck to be run, which might actually fix the problem, but this is ridiculous---it just silently trashes random files.
So I now have possibly-undetected filesystem damage. My -guess- is that only files written within a few minutes of the reset are likely to be affected, but I really don't know, and don't know of a good way to find out. Must I reinstall the OS -again-, starting from a blank partition, to be sure? Maybe I should just give up on ReiserFS completely.
[If there is a more-appropriate place for me to send this---such as a particular Mandrake list, or a particular ReiserFS list---please let me know, particularly if I can get a quick answer -without- going through the overhead of subscribing to the list, being flooded, and unsubscribing---that's what archives are for. Some websearching for "ReiserFS corruption" yielded -thousands- of hits---not a good sign---and a very large proportion of them were on this list, so I figure this is as good a place to ask as any. Thanks again.] - 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/
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