Messages in this thread |  | | From | Nikita Danilov <> | Date | Sat, 22 Sep 2001 16:47:31 +0400 | Subject | Re: ReiserFS data corruption in very simple configuration |
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foner-reiserfs@media.mit.edu writes: > [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.
Stock reiserfs only provides meta-data journalling. It guarantees that structure of you file-system will be correct after journal replay, not content of a files. It will never "trash" file that wasn't accessed at the moment of crash, though. Full data-journaling comes at cost. There is patch by Chris Mason <Mason@Suse.COM> to support data journaling in reiserfs. Ext3 supports it also.
> > 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
Reiserfs mail-list <Reiserfs-List@Namesys.COM>, archive at http://marc.theaimsgroup.com/?l=reiserfs&r=1&w=2
> 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.]
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