Re: Reiserfs munched directory on power failure

[Hans Reiser <reiser@namesys.com>]

What you experienced is what metadata journaling does when you crash in 
the middle of a write.  The ordered writes option should prevent your 
problem at only a modest performance loss.

Reiser4 is fully atomic and higher performance, I encourage you to use it.

Hans

Felix Finch wrote:

>I am running Linux 2.4.26 SMP with reiserfsprogs 3.6.4.  It is a dual
>Athlon with 1G of RAM.  I have had losses three times in reiserfs
>partitions when it loses power.  My mostly static partitions are ext3,
>all others are reiserfs.  This is Slackware 9.0.
>
>This poor machine is not behaving very well.  I added two disks to it,
>the power supply called it quits and apparently left some lingering
>resentment with the motherboard, maybe the processors, and now it
>shuts itself off for no reason every once in a while.  Sometimes it
>runs for a couple of minutes, other times for several days.  Not heat
>related, I think, because I wait for the disks to spin down, hit the
>power button, and it comes right back up.  It has failed on cold
>mornings and hot afternoons.  The only common denominator is that it
>has only failed when I am at the keyboard; I have never found it
>turned off when I wake up, or when I come home.
>
>I am awaiting parts to build a new machine.  Bummer!  Neato! :-)
>
>I tell you all this in case you decide it makes this bug report
>unreliable.  I am not certain of that, myself, because other than
>losing unsaved edits, the only other problems are from the Reiserfs
>partitions.
>
>I have had three reiserfs failures.
>
>One power failure occurred within a few seconds of opening a text file
>in emacs.  I do not remember if I had made any changes, but if I
>remember emacs correctly, it doesn't do anything with the original
>file until you tell it to save.  At any rate, soon after opening the
>file, power went bye-bye, and when I brought it back up, that file's
>2000 lines of Perl code had been replaced by about half the GPL.
>Luckily subversion had the original, so I did not lose anything.  No
>other files were damaged that I could tell.
>
>The other two were similar to each other, an hour or two apart.  I had
>just visited a site with mozilla when power failed.  When it came back
>up, and I restarted the browser, it had lost all my bookmarks and some
>of my preferences.  I regret that I cannot say with detail what files
>had gone walkabout, since I did not notice the corruption until I
>brought mozilla up, and mozilla had (re)written new files by the time
>I noticed.  I recovered everything from backup, and it hasn't lost
>power while surfing the web since.
>
>Mozilla does have LAST VISIT times in the bookmarks file, so it may
>well have been modifying the file when power failed.  I don't know
>what it would have been changing in the preferences file.
>
>I don't have any idea why the Perl code was replaced by the GPL, since
>I haven't done anything to the GPL file since I first vreated it many
>moons ago, and I had not written any changes to the file.
>
>The mozilla surprise was spookier, in some ways, but also more
>understandable if mozilla had just written new versions and the
>reiserfs journal is metadata only.
>
>Once I get the new machine built and it has replaced the old machine,
>I would be glad to help debug this, if it would help.  Installing a
>new 2.4 kernel is no problem, but 2.6 is perhaps too much hassle; I
>believe I would have to upgrade some utilities also.  But I can
>certainly turn on extra logging, edit in extra logging, cycle power at
>interesting times, etc.
>
>And of course if these "failures" are just symptomatic of metadata
>journaling and power failures, and you think they are all explainable
>by natural causes, that's fine too.
>
>I don't read this list, so cc: me if you want.
>
>  
>