Queued async events handling in CAM opened race, that may lead to duplicate
AC_PATH_REGISTERED events delivery during boot. That was not happening
before r272935 because the driver was initialized later. After that change
it started create duplicate ports in CTL.
Target mode operation does not depend on the initiator mode scan process.
This change allows the target driver to attach earlier and receive some
async events (like AC_CONTRACT) that could be lost otherwise.
MFC after: 1 week
Such LUNs will be visible to initiators, but return "not ready" status
on media access commands. If backing storage become available later,
`ctladm modify ...` or `service ctld reload` can trigger its reopen.
It allows to push out some final data from the send queue to the socket
before its close. In particular, it increases chances for logout response
to be delivered to the initiator.
Before this change target could send R2T request for write transfer of any
size, that could violate iSCSI RFC, which allows initiator to limit maximum
R2T size by negotiating MaxBurstLength connection parameter.
Also report an error in case of write underflow, when initiator provides
less data than initiator expects. Previously in such case our target
sent R2T request for non-existing data, violating the RFC, and confusing
some initiators. SCSI specs don't explicitly define how write underflows
should be handled and there are different oppinions, but reporting error
is hopefully better then violating iSCSI RFC with unpredictable results.
MFC after: 2 weeks
SPC-2 tells REPORT LUNS shall be supported by devices supporting LUNs other
then LUN 0. If we see LUN 0 disconnected, guess there may be others, and
so REPORT LUNS shall be supported.
MFC after: 1 month
Previous logic was not differentiating disconnected LUNs and absent targets.
That made it to stop scan if LUN 0 was not found for any reason. That made
problematic, for example, using iSCSI targets declaring SPC-2 compliance and
having no LUN 0 configured.
The new logic continues sequential LUN scan if:
-- we have more configured LUNs that need recheck;
-- this LUN is connected and its SCSI version allows more LUNs;
-- this LUN is disconnected, its SCSI version allows more LUNs and we
guess they may be connected (we haven't scanned first 8 LUNs yet or
kern.cam.cam_srch_hi sysctl is set to scan more).
Reported by: trasz
MFC after: 1 month
or I_T NEXUS LOSS, clear all minor UAs for the LUN, redundant in this case.
All SAM specifications tell that target MAY do it, but libiscsi initiator
seems require it to be done, terminating connection with error if some more
UAs happen to be reported during iSCSI connection.
MFC after: 3 days
Using pointer from the cdev directly is dangerous since we have no reference
on it, and it may change any time. That caused panic if device has gone.
While there, report capacity change only if it really changed.
MFC after: 3 days
Without clustering support we any way have only one group of permanently
active ports, but that gives us one more supported VMWare feature. ;)
Solaris' Comstar also reports it even when only one port is present.
devq_openings counter lost its meaning after allocation queues has gone.
held counter is still meaningful, but problematic to update due to separate
locking of CCB allocation and queuing.
To fix that replace devq_openings counter with allocated counter. held is
now calculated on request as difference between number of allocated, queued
and active CCBs.
MFC after: 1 month
It allows to bypass range checks between UNMAP and READ/WRITE commands,
which may introduce additional delays while waiting for UNMAP parameters.
READ and WRITE commands are always processed in safe order since their
range checks are almost free.
Before this change UNMAP completely blocked other I/Os while running.
Now it blocks only colliding ones, slowing down others only due to ZFS
locks collisions.
Sponsored by: iXsystems, Inc.
None of existing STEC devices need UNMAP or even support it well, having
many limitations and even hanging sometimes executing those commands.
New devices that may use UNMAP going to be released under HGST name.
MFC after: 3 days
kern.cam.ctl.iscsi.ping_timeout to 0. This fixes interoperability with
some initiators that don't properly support NOP-Ins, namely iPXE/gPXE.
Submitted by: Chen Wen <pokkys@gmail.com>
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
