zpool scrub causes geli vdev to detach

On:

FreeBSD TP51.local 7.0-CURRENT FreeBSD 7.0-CURRENT
#0: Thu Oct 11 09:21:19 CEST 2007
fk_at_TP51.local:/usr/obj/usr/src/sys/THINKPAD  i386

this zpool:

fk_at_TP51 ~ $sudo zpool status
  pool: tank
 state: ONLINE
 scrub: scrub completed with 0 errors on Thu Oct 11 13:56:28 2007
config:

        NAME          STATE     READ WRITE CKSUM
        tank          ONLINE       0     0     0
          ad0s3f.eli  ONLINE       0     0     0
          ad0s2.eli   ONLINE       0     0     0

errors: No known data errors

worked without issues when it only consisted of ad0s3f.eli,
but then I added ad0s2.eli and now scrubbing the pool leads to:

Unread portion of the kernel message buffer:
GEOM_ELI: Detached ad0s2.eli on last close.
GEOM_LABEL: Label for provider ad0s2 is msdosfs/ÒA.Û,{(#0.
panic: Function g_eli_orphan_spoil_assert() called for ad0s3f.eli.
KDB: enter: panic
panic: from debugger
Uptime: 5m27s
Physical memory: 1014 MB
Dumping 120 MB: 105 89 73 57 41 25 9

#0  doadump () at pcpu.h:195
195     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) bt   
#0  doadump () at pcpu.h:195
#1  0xc05db8f3 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:409
#2  0xc05dbb1c in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:563
#3  0xc04a40c7 in db_panic (addr=Could not find the frame base for "db_panic".
) at /usr/src/sys/ddb/db_command.c:433
#4  0xc04a4825 in db_command_loop () at /usr/src/sys/ddb/db_command.c:401
#5  0xc04a6255 in db_trap (type=3, code=0) at /usr/src/sys/ddb/db_main.c:222
#6  0xc06014a4 in kdb_trap (type=3, code=0, tf=0xf4bcac1c) at /usr/src/sys/kern/subr_kdb.c:502
#7  0xc0838d2b in trap (frame=0xf4bcac1c) at /usr/src/sys/i386/i386/trap.c:621
#8  0xc082120b in calltrap () at /usr/src/sys/i386/i386/exception.s:139
#9  0xc0601602 in kdb_enter (msg=0xc0889693 "panic") at cpufunc.h:60
#10 0xc05dbb05 in panic (fmt=0xc3e9a0e8 "Function %s() called for %s.") at /usr/src/sys/kern/kern_shutdown.c:547
#11 0xc3e92d65 in ?? ()
#12 0xc3e9a0e8 in ?? ()
#13 0xc3e99d84 in ?? ()
#14 0xc3e0d890 in ?? ()
#15 0xf4bcacac in ?? ()
#16 0xc058eff5 in g_spoil_event (arg=0xc3c92940, flag=-945983104) at /usr/src/sys/geom/geom_subr.c:903
(kgdb) f 16
#16 0xc058eff5 in g_spoil_event (arg=0xc3c92940, flag=-945983104) at /usr/src/sys/geom/geom_subr.c:903
903                     cp->geom->spoiled(cp);
(kgdb) l
898                     if (!cp->spoiled)
899                             continue;
900                     cp->spoiled = 0;
901                     if (cp->geom->spoiled == NULL)
902                             continue;
903                     cp->geom->spoiled(cp);
904                     g_topology_assert();
905             }
906     }
907     

As a workaround I'm currently using:

--- sys/geom/eli/g_eli.c.orig   2007-10-11 13:35:53.744592827 +0200
+++ sys/geom/eli/g_eli.c        2007-10-11 13:38:41.687509241 +0200
_at__at_ -451,10 +451,14 _at__at_
        gp = sc->sc_geom;
        pp = LIST_FIRST(&gp->provider);
        strlcpy(ppname, pp->name, sizeof(ppname));
+
+       G_ELI_DEBUG(0, "Ignored request to detach %s on last close.", ppname);
+        /*
        error = g_eli_destroy(sc, 1);
        KASSERT(error == 0, ("Cannot detach %s on last close (error=%d).",
            ppname, error));
        G_ELI_DEBUG(0, "Detached %s on last close.", ppname);
+        */
 }
 
 int

and with that scrubbing finishes without errors (see status above),
but triggers the G_ELI_DEBUG message once or twice:

Oct 11 13:46:30 TP51 sudo:       fk : TTY=ttyv0 ; PWD=/home/fk ; USER=root ; COMMAND=/etc/rc.d/zfs start
Oct 11 13:46:31 TP51 kernel: WARNING: ZFS is considered to be an experimental feature in FreeBSD.
Oct 11 13:46:31 TP51 kernel: ZFS filesystem version 6
Oct 11 13:46:31 TP51 kernel: ZFS storage pool version 6
Oct 11 13:46:32 TP51 kernel: GEOM_ELI: Ignored request to detach ad0s3f.eli on last close.
Oct 11 13:46:32 TP51 last message repeated 3 times
Oct 11 13:46:32 TP51 kernel: GEOM_ELI: Ignored request to detach ad0s2.eli on last close.
Oct 11 13:46:44 TP51 sudo:       fk : TTY=ttyv0 ; PWD=/home/fk ; USER=root ; COMMAND=/sbin/zpool status
Oct 11 13:47:12 TP51 sudo:       fk : TTY=ttyv0 ; PWD=/home/fk ; USER=root ; COMMAND=/sbin/zpool scrub tank
Oct 11 13:47:13 TP51 kernel: GEOM_ELI: Ignored request to detach ad0s3f.eli on last close.
Oct 11 13:47:13 TP51 kernel: GEOM_ELI: Ignored request to detach ad0s3f.eli on last close.

Not sure if it helps, but the zdevs are:

Geom name: ad0s3f.eli
EncryptionAlgorithm: AES-CBC
KeyLength: 128
Crypto: software
UsedKey: 0
Flags: RW-DETACH, W-OPEN
Providers:
1. Name: ad0s3f.eli
   Mediasize: 8881561600 (8.3G)
   Sectorsize: 4096
   Mode: r1w1e1
Consumers:
1. Name: ad0s3f
   Mediasize: 8881565184 (8.3G)
   Sectorsize: 512
   Mode: r1w1e1

Geom name: ad0s2.eli
EncryptionAlgorithm: AES-CBC
KeyLength: 128
Crypto: software
UsedKey: 0
Flags: RW-DETACH, W-OPEN
Providers:
1. Name: ad0s2.eli
   Mediasize: 9932263424 (9.3G)
   Sectorsize: 4096
   Mode: r1w1e1
Consumers:
1. Name: ad0s2
   Mediasize: 9932267520 (9.3G)
   Sectorsize: 512
   Mode: r1w1e1


Is there an obvious solution, or should I file a PR about this?

Fabian