From: jhood@smoke.marlboro.vt.us (John Hood) Subject: Re: SERIOUS Smail v3.1.28.1 locking problems! Date: Sat, 1 May 1993 19:37:43 GMT
In article <1rs8vr$2kp@adv.win.tue.nl> devet@adv.win.tue.nl (Arjan de Vet) writes:
>In article <1993Apr23.022843.1930@rgm2.rgm.com> ray@rgm2.rgm.com (Ray
>Mendonsa) writes:
>
>>If I receive two mails in the same uucp batch and uuxqt executes two
>>or more "rmail user"'s back to back, a locking problem seems to
>>occur.
>>
>>The two messages get written at the same time, scrambling the two
>>messages together, and truncating parts. I'm using Taylor v1.04
>>uuxqt and smail v3.1.28.1 #28.6 for rmail . Any tips, fixes, or
>>workarounds are most appreciated.
>
>I noticed this behaviour when INN 1.4 mailed (at the same time) 3 checkgroup
>messages which were received and processed as three separate mails
>(according to the log files) but showed up as ONE mail-message containing
>these messages (partially scrambled).
>
>My uuxqt executes rmail commands sequentially so I hadn't seen it earlier.
>
>>BTW, the smail was included in the SLS release as of mid-March.
>
>I compiled smail myself but will try again with some different lock settings.
>This is a *serious* problem.
This is a race problem in the file systems that allows multiple files
with the same name to be created (in this case, smail lockfiles). I
had this problem too. I ended up developing a test for it, and I was
all set to start digging into the kernel to figure it out when ext2fs
0.3 came out, which has a fix for it (I use ext2fs). The fix doesn't
absolutely guarantee correct behavior, but my tests show no problem
with the file system (although I did find a bash memory leak I still
have to get back to. :) I think Linus has said he's implemented a
similar fix for the minix fs.
In other words, if you're using ext2fs, upgrade to 99p9.
-jh
(of course, now I'm having a problem with the same message appearing
in my mailbox twice, but that's much more tolerable.)
-- John Hood Cthulhu-- just imagine it! jhood@smoke.marlboro.vt.us