VTL emulation, no barcodes shown in mtx

VTL emulation, no barcodes shown in mtx

[Michael Ablassmeier]

hi,

im trying to create a virtual tape library based on the DVD/CD example,
the commands used are:

> tgtadm --op new --mode logicalunit --tid 1 --lun 1 --device-type tape 
> tgtadm --lld iscsi --mode logicalunit --op update --tid 1 --lun 1 --params vendor_id=IBM,product_id=LTO1,product_rev=0010,scsi_sn=IBMLTO1,removable=1
> tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 2 --backing-store $HOME/smc --device-type changer
> tgtadm --lld iscsi --mode logicalunit --op update --tid 1 --lun 2 --params vendor_id=STK,product_id=L700,product_rev=0010,scsi_sn=XYZZY_0,removable=1
> tgtadm --lld iscsi --mode logicalunit --op update --tid 1 --lun 2 --params element_type=4,start_address=1,quantity=1
> tgtadm --lld iscsi --mode logicalunit --op update --tid 1 --lun 2 --params element_type=4,address=1,tid=1,lun=1
> tgtadm --lld iscsi --mode logicalunit --op update --tid 1 --lun 2 --params element_type=1,start_address=16,quantity=1
> tgtadm --lld iscsi --mode logicalunit --op update --tid 1 --lun 2 --params media_home=${VTL}
> tgtadm --lld iscsi --mode logicalunit --op update --tid 1 --lun 2 --params element_type=2,start_address=1024,quantity=8
> tgtadm --lld iscsi --mode logicalunit --op update --tid 1 --lun 2 --params element_type=2,address=1024,barcode=TAPE001,sides=1
> tgtadm --lld iscsi --mode logicalunit --op update --tid 1 --lun 2 --params element_type=2,address=1025,barcode=TAPE002,sides=1

while the device seems to work (loading and unloading the vtl medias),
mtx and other tools i used to query the VTL do not show any barcodes:

> mtx -f /dev/sg8 status
> Storage Changer /dev/sg8:1 Drives, 8 Slots ( 0 Import/Export )
> Data Transfer Element 0:Empty
> Storage Element 1:Full 
> Storage Element 2:Full 
> Storage Element 3:Empty:VolumeTag=

(4.19.0, 1.0.74)

am i missing something?

thanks,
    - michael

Re: VTL emulation, no barcodes shown in mtx

[Michael Ablassmeier]

On Wed, Jan 06, 2021 at 07:58:25PM +0100, Michael Ablassmeier wrote:
> im trying to create a virtual tape library based on the DVD/CD example,
> the commands used are:
> 
> > tgtadm --op new --mode logicalunit --tid 1 --lun 1 --device-type tape 
> > [..]

The output is missing the relevant image commands which were used to
create the medias:

> tgtimg --op new --device-type tape --type DATA --barcode TAPE001 --size 500 --file ${VTL}/TAPE001
> tgtimg --op new --device-type tape --type DATA --barcode TAPE002 --size 500 --file ${VTL}/TAPE002

thanks,
    - michael

Re: VTL emulation, no barcodes shown in mtx

[Michael Ablassmeier]

hi again,

On Wed, Jan 06, 2021 at 07:58:25PM +0100, Michael Ablassmeier wrote:
> > mtx -f /dev/sg8 status
> > Storage Changer /dev/sg8:1 Drives, 8 Slots ( 0 Import/Export )
> > Data Transfer Element 0:Empty
> > Storage Element 1:Full 
> > Storage Element 2:Full 
> > Storage Element 3:Empty:VolumeTag=

it seems this i a regression introduced by one of the following commits
to smc.c:

 >  commit 2de8bebe132e3b998bf4848d0bd22b50367ad4b8
 >  Author: Lee Duncan <lduncan@suse.com>
 >  Date:   Sat Feb 16 10:29:19 2019 -0800
 > 
 >      Fix gcc7 string truncation warnings.

 > commit 73cb8f355479d8f7cb402ca967b137d4a32c8f76
 > Author: FUJITA Tomonori <tomof@acm.org>
 > Date:   Fri Jul 28 11:34:15 2017 +0900
 >     smc: fix snprintf warnings with gcc7

i reverted both commits and removed -WAll from the makefile to be
able to compile, and now mtx show the barcodes:

 >  Storage Changer /dev/sg8:1 Drives, 8 Slots ( 0 Import/Export )
 >  Data Transfer Element 0:Empty
 >        Storage Element 1:Full :VolumeTag=TAPE001                        
 >        Storage Element 2:Full :VolumeTag=TAPE002  


bye,
    - michael

Re: [PATCH] VTL emulation, no barcodes shown in mtx

[Michael Ablassmeier]

[-- Attachment #1: Type: text/plain, Size: 698 bytes --]

hi,

attached patch should fix this regression.

On Wed, Jan 06, 2021 at 11:08:05PM +0100, Michael Ablassmeier wrote:
>  > commit 73cb8f355479d8f7cb402ca967b137d4a32c8f76
>  > Author: FUJITA Tomonori <tomof@acm.org>
>  > Date:   Fri Jul 28 11:34:15 2017 +0900
>  >     smc: fix snprintf warnings with gcc7
> 
> i reverted both commits and removed -WAll from the makefile to be
> able to compile, and now mtx show the barcodes:
> 
>  >  Storage Changer /dev/sg8:1 Drives, 8 Slots ( 0 Import/Export )
>  >  Data Transfer Element 0:Empty
>  >        Storage Element 1:Full :VolumeTag=TAPE001                        
>  >        Storage Element 2:Full :VolumeTag=TAPE002  
> 
> 
> bye,
>     - michael

[-- Attachment #2: patch.diff --]
[-- Type: text/x-diff, Size: 424 bytes --]

diff --git a/usr/smc.c b/usr/smc.c
index bbc7b7f..5efcbd7 100644
--- a/usr/smc.c
+++ b/usr/smc.c
@@ -184,7 +184,7 @@ static int add_element_descriptor(uint8_t *data, struct slot *s,
 		{
 			char buf[sizeof(attr->scsi_sn) + 1];
 			memset(buf, 0, sizeof(buf));
-			snprintf(buf, sizeof(buf), "%-s", attr->scsi_sn);
+			snprintf(buf, sizeof(buf), "%-10s", attr->scsi_sn);
 			memcpy((char *)&data[i + 28], buf, 10);
 		}
 	}

Re: [PATCH] VTL emulation, no barcodes shown in mtx

[Michael Ablassmeier]

On Wed, Jan 06, 2021 at 11:28:42PM +0100, Michael Ablassmeier wrote:
> attached patch should fix this regression.

please ignore, this was actually an issue with the old version i was
using, already beeing addressed in 1.0.80 :)

sorry for all the noise,

bye,
    - michael