kern/49072: in-kernel iscsi initiator not working

[zafer%aydogan.de@localhost]

>Number:         49072
>Category:       kern
>Synopsis:       in-kernel iscsi initiator not working
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Aug 04 23:30:00 +0000 2014
>Originator:     Zafer Aydogan
>Release:        6.99.16 onward
>Organization:
TNF
>Environment:
6.99.49 amd64
>Description:
The in-kernel iscsi initiator looks like to be broken since 6.99.16.
Symptoms are scsi SENSE KEY errors with "Overlapped Commands Attempted"
when you write data to disk.
If you continue to write data to the iscsi disk, the write process will wedge 
in tstile.
In this state a reboot will not succeed. You need to power-cycle.
Sometimes writing to the disk will panic the system, especially overwriting the 
same file frequently.

I could trace the error back to two commits from mlelstv@ on 2012-12-29:
http://freshbsd.org/commit/netbsd/0407d4dcf2917f3861618fc1cbc54e6bd5b583b3
and
http://freshbsd.org/commit/netbsd/77a0b440f42ba059ed279f043194a4b589203054
If you revert both or use a version prior to that date, iscsi works as expected 
without any issues.

Screenshots:
http://www.aydogan.de/wtfs.png
http://www.aydogan.de/iscsi_panic.png

>How-To-Repeat:
mount an iscsi share and
newfs -O1 on a partition

newfs will exit with a wtfs write error

Attention: newfs -O2 will show no errors.


>Fix:
A workaround is to revert to the version before 2012-12-29 08:00:00