Weird CAM-ATA behaviour (8.0-RC1): disk cloning

Hello,

I just noticed something weird in my device list (actually, I noticed it 
in "glabel status" output, but then confirmed via camcontrol devlist): I 
got a 7th HDD, ada6, which is, surprisingly, ada0.

This is how it appeared (I've checked the logs):

Oct 27 01:26:38 ameagari sudo: fujibayashi : TTY=pts/3 ; 
PWD=/usr/home/fujibayashi ; USER=root ; COMMAND=/sbin/camcontrol rescan 
0:0:1
Oct 27 01:26:38 ameagari kernel: (aprobe0:ahcich0:0:0:1): SIGNATURE: 0000
Oct 27 01:26:38 ameagari kernel: ada6 at ahcich0 bus 0 target 0 lun 1
Oct 27 01:26:38 ameagari kernel: ada6: <ST3500320AS SD15> ATA/ATAPI-8 
SATA 2.x device
Oct 27 01:26:38 ameagari kernel: ada6: 300.000MB/s transfers
Oct 27 01:26:38 ameagari kernel: ada6: 476940MB (976773168 512 byte 
sectors: 16H 63S/T 16383C)
Oct 27 01:26:38 ameagari kernel: ada6: Native Command Queueing enabled
Oct 27 01:26:38 ameagari kernel: GEOM_MIRROR: Cannot add disk ada6 to 
gm0 (error=17).

While I know I made a mistake there (specifying 0:0:1 instead of 1:0:0), 
is this behaviour really correct? I don't see why we should add a 
'cloned' disk device on a rescan of LUNs that do not really exist in the 
first place.

This is repeatable and I can create as many clones as I want (by doing 
"camcontrol rescan X:Y:Z" where Y and Z can vary and X is the AHCI bus 
number):

Oct 31 04:15:55 ameagari sudo: fujibayashi : TTY=pts/3 ; PWD=/usr/src ; 
USER=root ; COMMAND=/sbin/camcontrol rescan 0:1:1
Oct 31 04:15:55 ameagari kernel: (aprobe0:ahcich0:0:1:1): SIGNATURE: 0000
Oct 31 04:15:55 ameagari kernel: ada7 at ahcich0 bus 0 target 1 lun 1
Oct 31 04:15:55 ameagari kernel: ada7: <ST3500320AS SD15> ATA/ATAPI-8 
SATA 2.x device
Oct 31 04:15:55 ameagari kernel: ada7: 300.000MB/s transfers
Oct 31 04:15:55 ameagari kernel: ada7: 476940MB (976773168 512 byte 
sectors: 16H 63S/T 16383C)
Oct 31 04:15:55 ameagari kernel: ada7: Native Command Queueing enabled
Oct 31 04:15:55 ameagari kernel: GEOM_MIRROR: Cannot add disk ada7 to 
gm0 (error=17).
Oct 31 04:15:55 ameagari kernel: GEOM: ada7s1: geometry does not match 
label (255h,63s != 16h,63s).


Here's camcontrol output before rescan of 0:1:1:

fujibayashi_at_ameagari /usr/src % sudo camcontrol devlist -v
scbus0 on ahcich0 bus 0:
<ST3500320AS SD15>                 at scbus0 target 0 lun 0 (pass0,ada0)
<ST3500320AS SD15>                 at scbus0 target 0 lun 1 (ada6,pass6)
<>                                 at scbus0 target -1 lun -1 ()
scbus1 on ahcich1 bus 0:
<ST3500320AS SD15>                 at scbus1 target 0 lun 0 (pass1,ada1)
<>                                 at scbus1 target -1 lun -1 ()
scbus2 on ahcich2 bus 0:
<WDC WD5000AACS-00G8B0 05.04C05>   at scbus2 target 0 lun 0 (pass2,ada2)
<>                                 at scbus2 target -1 lun -1 ()
scbus3 on ahcich3 bus 0:
<ST3500320AS SD15>                 at scbus3 target 0 lun 0 (pass3,ada3)
<>                                 at scbus3 target -1 lun -1 ()
scbus4 on ahcich4 bus 0:
<ST3750330AS SD15>                 at scbus4 target 0 lun 0 (pass4,ada4)
<>                                 at scbus4 target -1 lun -1 ()
scbus5 on ahcich5 bus 0:
<ST3750330AS SD15>                 at scbus5 target 0 lun 0 (pass5,ada5)
<>                                 at scbus5 target -1 lun -1 ()
scbus-1 on xpt0 bus 0:
<>                                 at scbus-1 target -1 lun -1 (xpt0)


fujibayashi_at_ameagari /usr/src % uname -a
FreeBSD ameagari.fujibayashi.jp 8.0-RC1 FreeBSD 8.0-RC1 #29 r198327: Fri 
Oct 23 05:29:41 JST 2009     
root_at_ameagari.fujibayashi.jp:/usr/obj/usr/src/sys/Ameagari  amd64

--
Kamigishi Rei
KREI-RIPE