Re: [Bugme-new] [Bug 7717] New: Tapes unreadable after unload

Re: [Bugme-new] [Bug 7717] New: Tapes unreadable after unload

[Andrew Morton]

(please respond via emailed reply-to-all)

On Wed, 20 Dec 2006 02:31:18 -0800
bugme-daemon@bugzilla.kernel.org wrote:

> http://bugzilla.kernel.org/show_bug.cgi?id=7717
> 
>            Summary: Tapes unreadable after unload
>     Kernel Version: tested 2.6.17 through 2.6.29 with various results

I assume that means 2.6.17 and 2.6.19 failed.

>             Status: NEW
>           Severity: blocking
>              Owner: io_scsi@kernel-bugs.osdl.org
>          Submitter: bgs@bgs.hu
> 
> 
> Most recent kernel where this bug did *NOT* occur: 2.6.19

And that means that 2.6.19 did not fail.

Please clarify.

> Distribution: Slackware/Fedora
> Hardware Environment: HP 530, HP Dl380
> Software Environment: tar, mtx
> Problem Description: Doing a tar backup works well. Data is written and is
> readable. Binary restore comparison is ok. After unload/load the tape produces
> Input/output errors. The tape is unreadable with working kernels too. Any
> attempt to restore data from faulty tapes were in vain until now. 
> 
> Steps to reproduce:
> tar cvf /dev/st0 /path/to/something
> mtx -f /dev/sg1 unload
> mtx -f /dev/sg1 load X
> tar tvf /dev/st0
> 
> tar output:
> tar: /dev/st0: Cannot read: Input/output error
> tar: At beginning of tape, quitting now
> tar: Error is not recoverable: exiting now
> 
> All read() attempts fail after 42 bytes. (I can attach those 42 bytes if they
> are of any help).

Re: [Bugme-new] [Bug 7717] New: Tapes unreadable after unload

[Bgs]

Andrew Morton wrote:
>>     Kernel Version: tested 2.6.17 through 2.6.29 with various results
> 
> I assume that means 2.6.17 and 2.6.19 failed.

I tested it with 2.6.17 through 2.6.19 including subversions (like 
2.6.17.3 and such). I found that 2.6.19 works and also found two other 
version in the line that work. The other about 4-5 version that I have 
tried, did not work. The works/not works is not consistent as I found 
2.6.17.x kernel that did work and 2.6.18 that did not.

If the problem is known, I'd also like to know what the problem was as I 
need to recover two tapes that are inaccessible now. (LTO3 400GB tapes 
so there was no time to erase all data even if something near the 
beginning of the tape is bad).


>>             Status: NEW
>>           Severity: blocking
>>              Owner: io_scsi@kernel-bugs.osdl.org
>>          Submitter: bgs@bgs.hu
>>
>>
>> Most recent kernel where this bug did *NOT* occur: 2.6.19
> 
> And that means that 2.6.19 did not fail.

Right now I'm using 2.6.19 and it works. Haven't tried it with 2.6.19.1 
yet though.

Re: [Bugme-new] [Bug 7717] New: Tapes unreadable after unload

[Kai Makisara]

On Wed, 20 Dec 2006, Andrew Morton wrote:

> 
> (please respond via emailed reply-to-all)
> 
> On Wed, 20 Dec 2006 02:31:18 -0800
> bugme-daemon@bugzilla.kernel.org wrote:
> 
> > http://bugzilla.kernel.org/show_bug.cgi?id=7717
> > 
> >            Summary: Tapes unreadable after unload
> >     Kernel Version: tested 2.6.17 through 2.6.29 with various results
> 
> I assume that means 2.6.17 and 2.6.19 failed.
> 
> >             Status: NEW
> >           Severity: blocking
> >              Owner: io_scsi@kernel-bugs.osdl.org
> >          Submitter: bgs@bgs.hu
> > 
> > 
> > Most recent kernel where this bug did *NOT* occur: 2.6.19
> 
> And that means that 2.6.19 did not fail.
> 
> Please clarify.
> 
> > Distribution: Slackware/Fedora
> > Hardware Environment: HP 530, HP Dl380
> > Software Environment: tar, mtx
> > Problem Description: Doing a tar backup works well. Data is written and is
> > readable. Binary restore comparison is ok. After unload/load the tape produces
> > Input/output errors. The tape is unreadable with working kernels too. Any
> > attempt to restore data from faulty tapes were in vain until now. 
> > 
> > Steps to reproduce:
> > tar cvf /dev/st0 /path/to/something
> > mtx -f /dev/sg1 unload
> > mtx -f /dev/sg1 load X
> > tar tvf /dev/st0
> > 

I tried this with 2.6.19 and the tape was readable. Unfortunately I don't 
have any older kernels around to test. I have not heard about any problem 
like this.

Note that the data becomes unreadable after the tape is touched by mtx 
through sg device, i.e, bypassing st.

> > tar output:
> > tar: /dev/st0: Cannot read: Input/output error
> > tar: At beginning of tape, quitting now
> > tar: Error is not recoverable: exiting now
> > 
Do you find any messages with dmesg or in system log?

> > All read() attempts fail after 42 bytes. (I can attach those 42 bytes if they
> > are of any help).
> 
Interesting byte count :-)

-- 
Kai