MFC r310640, r310643:
Add support for revert to defaults (RTD) bit in MODE SELECT.

MFC r310478: Add place-holders for TAPE STREAM MIRRORING subcommands of XCOPY.

We do not support tapes, so this is only a comments.

MFC r310390: Add support for REPD bit in RSTMF command.

We have no real timeout values to report there, but its better then error.

r310389:
Fix REPORT SUPPORTED OPERATION CODES for READ/WRITE BUFFER commands.

Specifications require MODE parameter of those commands to be treated
the same as SERVICE ACTION parameter of other commands.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Really implement PREVENT ALLOW MEDIUM REMOVAL command.

Don't report SYNC_NV bit set in SYNCHRONIZE CACHE as error.

While this bit is obsolete in SBC-3, behavior controlled by it is allowed
on device discretion.

Umplement media load/eject support for removable devices.

In case of block backend eject really closes the backing store, while
load tries to open it back. Failed store open is reported as no media.

Add to CTL initial support for CDROMs and removable devices.

Relnotes: yes

Allow LOG SENSE command on non-disk devices.

Fix bit masks changed for the wrong commands in r288221.

Remove some dead code found by Clang analyzer.

Add support for READ BUFFER(16) command.

Always execute REPORT LUNS and REQUEST SENSE commands locally.

REPORT LUNS command is more related to target rather then specific LUN.
This node may be primary for LUNs for some reason unknown to another,
and command forwarded to another node won't be able to report them.

REQUEST SENSE is related to LUN, but in our implementation it reports
only UAs and CAs, that are stored locally rather then on primary node.

Split two command flags with different meaning.

This is only a cosmetical change.

Improve read-only support.

Correct RTPG bitmask.

Reimplement CTL High Availability.

CTL HA functionality was originally implemented by Copan many years ago,
but large part of the sources was never published. This change includes
clean room implementation of the missing code and fixes for many bugs.

This code supports dual-node HA with ALUA in four modes:
- Active/Unavailable without interlink between nodes;
- Active/Standby with second node handling only basic LUN discovery and
reservation, synchronizing with the first node through the interlink;
- Active/Active with both nodes processing commands and accessing the
backing storage, synchronizing with the first node through the interlink;
- Active/Active with second node working as proxy, transfering all
commands to the first node for execution through the interlink.

Unlike original Copan's implementation, depending on specific hardware,
this code uses simple custom TCP-based protocol for interlink. It has
no authentication, so it should never be enabled on public interfaces.

The code may still need some polishing, but generally it is functional.

Relnotes: yes
Sponsored by: iXsystems, Inc.

Drop "internal" CTL frontend.

Its idea was to be a simple initiator and execute several commands from
kernel level, but FreeBSD never had consumer for that functionality,
while its implementation polluted many unrelated places..

Pass SYNCHRONIZE CACHE command parameters to backends.

At this point IMMED flag is translated to MNT_NOWAIT flag of VOP_FSYNC(),
hoping that file system implements that (ZFS seems doesn't).

MFC after: 2 weeks
Sponsored by: iXsystems, Inc.

Relax serialization of SYNCHRONIZE CACHE commands.

Before this change SYNCHRONIZE CACHE commands were executed exclusively,
as if they had ORDERED tag. But looking through SCSI specs I've found
no any reason to be so strict. For reads this ordering seems pointless.
For writes it looks less obvious, so I left ordering against preceeding
write commands, while following ones are no longer required to wait.

MFC after: 2 weeks
Sponsored by: iXsystems, Inc.

Do not count RCTD bit set as an error.

We can not really implement it, but specification tells that it "shall"
work, so it can be safely ignored.

MFC after: 1 week

Add GET LBA STATUS command support to CTL.

It is implemented for LUNs backed by ZVOLs in "dev" mode and files.
GEOM has no such API, so for LUNs backed by raw devices all LBAs will
be reported as mapped/unknown.

MFC after: 2 weeks
Sponsored by: iXsystems, Inc.

Partially reconstruct Active/Standby clusting.

In this mode one head is in Active state, supporting all commands, while
another is in Standby state, supporting only minimal LUN discovery subset.

It is still incomplete since Standby state requires reservation support,
which is impossible to do right without having interlink between heads.
But it allows to run some basic experiments.

Handle PREEMPT AND ABORT service action equal to PREEMPT.

With command serialization used in CTL, there are no other commands to abort
when PREEMPT AND ABORT gets to run, so it is practically equal to PREEMPT.

MFC after: 1 week

Reduce code duplication around Write Exclusive persistent reservation.

While there, allow some more commands to pass persistent reservation.

MFC after: 1 week

Some groundwork for later Informational Exceptions support.

This includes support for:
- Read-Write Error Recovery mode page;
- Informational Exceptions Control mode page;
- Logical Block Provisioning mode page;
- LOG SENSE command.

No real Informational Exceptions features yet. This is only a placeholder.

Sponsored by: iXsystems, Inc.

Add support for READ DEFECT DATA (10/12) commands.

SPC-4 r2 allows to return empty defect list if the list is not supported.
We don't reallu support defect data lists, but this suppresses some errors.

MFC after: 1 week

Make ctld start even if some LUNs are unable to open backing storage.

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.

Add support for WRITE ATOMIC (16) command and report SBC-4 compliance.

Atomic writes are only supported for ZVOLs in "dev" mode. In other cases
atomicity can not be guarantied and so the command is blocked.

Pretend that we support BYTCHK=1 in WRITE AND VERIFY command.

Technically that is not true, but since we don't implement VERIFY there
at all, doing only WRITE part, this is a minor sin.

Don't report unsupported FUA_NV bit set in READ/WRITE commands as error.

While this bit is obsolete in SBC-3, SBC-2 allowed to silently ignore it.

Allow SUBPAGE CODE field in MODE SENSE commands.

Allow more commands to pass persistent reservation according to SPC-4 r37.

Add support for "no Data-Out Buffer" (NDOB) flag of WRITE SAME (16) command.

Fix several issues and inconsistencies in UNMAP capabilities reporting.

This makes Windows 2012 to start using UNMAP on our disks.

MFC after: 2 weeks
Sponsored by: iXsystems, Inc.

Add support for Windows dialect of EXTENDED COPY command, aka Microsoft ODX.

This allows to avoid extra network traffic when copying files on NTFS iSCSI
disks within one storage host by drag'n'dropping them in Windows Explorer
of Windows 8/2012. It should also accelerate Hyper-V VM operations, etc.

MFC after: 2 weeks
Sponsored by: iXsystems, Inc.

Add support for VMWare dialect of EXTENDED COPY command, aka VAAI Clone.

This allows to clone VMs and move them between LUNs inside one storage
host without generating extra network traffic to the initiator and back,
and without being limited by network bandwidth.

LUNs participating in copy operation should have UNIQUE NAA or EUI IDs set.
For LUNs without these IDs VMWare will use traditional copy operations.

Beware: the above LUN IDs explicitly set to values non-unique from the VM
cluster point of view may cause data corruption if wrong LUN is addressed!

MFC after: 2 weeks
Sponsored by: iXsystems, Inc.

Merge several equal serialization indexes.

Add support for READ FULL STATUS action of PERSISTENT RESERVE IN command.

Fix bugs for PERSISTENT RESERVE OUT bits in r268096.

Relax some bit checks for INQUIRY command.

FreeBSD still tries to put LUN number in second byte until it get device
protocol version, even that it was obsoleted about 20 years ago.

Add support for REPORT TIMESTAMP command.

MFC after: 2 weeks

Add more formal and strict command parsing and validation.

For every supported command define CDB length and mask of bits that are
allowed to be set. This allows to remove bunch of checks through the code
and still make the validation more strict. To properly do it for commands
supporting multiple service actions, formalize their parsing by adding
subtables for each of such commands.

As visible effect, this change allows to add support for REPORT SUPPORTED
OPERATION CODES command, reporting to client all the data about supported
SCSI commands, except timeouts.

MFC after: 2 weeks

Allow MODE SENSE commands through Write Exclusive persistent reservation,
as required by SPC-4.

Report that fact in persistent reservation capabilities.

MFC after: 2 weeks

Add READ BUFFER and improve WRITE BUFFER SCSI commands support.

This gives some use to 512KB per-LUN buffers, allocated for Copan-specific
processor code and not used. It allows, for example, to test transport
performance and/or correctness without accessing the media, as supported
by Linux version of sg3_utils.

MFC after: 2 weeks

Add support for VERIFY(10/12/16) and COMPARE AND WRITE SCSI commands.

Make data_submit backends method support not only read and write requests,
but also two new ones: verify and compare. Verify just checks readability
of the data in specified location without transferring them outside.
Compare reads the specified data and compares them to received data,
returning error if they are different.

VERIFY(10/12/16) commands request either verify or compare from backend,
depending on BYTCHK CDB field. COMPARE AND WRITE command executed in two
stages: first it requests compare, and then, if succeesed, requests write.
Atomicity of operation is guarantied by CTL request ordering code.

MFC after: 2 weeks
Sponsored by: iXsystems, Inc.

Introduce new serialization type CTL_SERIDX_UNMAP.

Unfortunately we can't check range collisions for UNMAP commands alike
to writes, because they include multiple ranges, which are also passed
in data block, not in CDB. As result, UNMAP commands have to be treated
as colliding with any other command accessing the media.

From the other side all UNMAPs are equal (we don't support ANCHOR flag),
so we can execute several UNMAPs same time.

Add support for SCSI UNMAP commands to CTL.

This patch adds support for three new SCSI commands: UNMAP, WRITE SAME(10)
and WRITE SAME(16). WRITE SAME commands support both normal write mode
and UNMAP flag. To properly report UNMAP capabilities this patch also adds
support for reporting two new VPD pages: Block limits and Logical Block
Provisioning.

UNMAP support can be enabled per-LUN by adding "-o unmap=on" to `ctladm
create` command line or "option unmap on" to lun sections of /etc/ctl.conf.

At this moment UNMAP supported for ramdisks and device-backed block LUNs.
It was tested to work great with ZFS ZVOLs. For file-backed LUNs UNMAP
support is unfortunately missing due to absence of respective VFS KPI.

Reviewed by: ken
MFC after: 1 month
Sponsored by: iXsystems, Inc

Change the SCSI INQUIRY peripheral qualifier that CTL reports for LUNs
that don't exist.

Anecdotal evidence indicates that it is better to return 011b (bad LUN)
than 001b (LUN offline). However, this change also gives the user a
sysctl/tunable, kern.cam.ctl.inquiry_pq_no_lun, to override the change
and return to the previous behavior. (The previous behavior was to
return 001b, or LUN offline.)

ctl.c: Change the default inquiry peripheral qualifier to 011b,
and add a sysctl and tunable to allow the user to change
it back to 001b if needed.

Don't insert a Copan copyright statement in the inquiry
data. The copyright statements on the files are
sufficient.

ctl_private.h: Add sysctl variable context to the CTL softc.

ctl_cmd_table.c,
ctl_frontend_internal.c,
ctl_frontend.c,
ctl_backend.c,
ctl_error.c: Include sys/sysctl.h.

MFC after: 3 days

Add the CAM Target Layer (CTL).

CTL is a disk and processor device emulation subsystem originally written
for Copan Systems under Linux starting in 2003. It has been shipping in
Copan (now SGI) products since 2005.

It was ported to FreeBSD in 2008, and thanks to an agreement between SGI
(who acquired Copan's assets in 2010) and Spectra Logic in 2010, CTL is
available under a BSD-style license. The intent behind the agreement was
that Spectra would work to get CTL into the FreeBSD tree.

Some CTL features:

- Disk and processor device emulation.
- Tagged queueing
- SCSI task attribute support (ordered, head of queue, simple tags)
- SCSI implicit command ordering support. (e.g. if a read follows a mode
select, the read will be blocked until the mode select completes.)
- Full task management support (abort, LUN reset, target reset, etc.)
- Support for multiple ports
- Support for multiple simultaneous initiators
- Support for multiple simultaneous backing stores
- Persistent reservation support
- Mode sense/select support
- Error injection support
- High Availability support (1)
- All I/O handled in-kernel, no userland context switch overhead.

(1) HA Support is just an API stub, and needs much more to be fully
functional.

ctl.c: The core of CTL. Command handlers and processing,
character driver, and HA support are here.

ctl.h: Basic function declarations and data structures.

ctl_backend.c,
ctl_backend.h: The basic CTL backend API.

ctl_backend_block.c,
ctl_backend_block.h: The block and file backend. This allows for using
a disk or a file as the backing store for a LUN.
Multiple threads are started to do I/O to the
backing device, primarily because the VFS API
requires that to get any concurrency.

ctl_backend_ramdisk.c: A "fake" ramdisk backend. It only allocates a
small amount of memory to act as a source and sink
for reads and writes from an initiator. Therefore
it cannot be used for any real data, but it can be
used to test for throughput. It can also be used
to test initiators' support for extremely large LUNs.

ctl_cmd_table.c: This is a table with all 256 possible SCSI opcodes,
and command handler functions defined for supported
opcodes.

ctl_debug.h: Debugging support.

ctl_error.c,
ctl_error.h: CTL-specific wrappers around the CAM sense building
functions.

ctl_frontend.c,
ctl_frontend.h: These files define the basic CTL frontend port API.

ctl_frontend_cam_sim.c: This is a CTL frontend port that is also a CAM SIM.
This frontend allows for using CTL without any
target-capable hardware. So any LUNs you create in
CTL are visible in CAM via this port.

ctl_frontend_internal.c,
ctl_frontend_internal.h:
This is a frontend port written for Copan to do
some system-specific tasks that required sending
commands into CTL from inside the kernel. This
isn't entirely relevant to FreeBSD in general,
but can perhaps be repurposed.

ctl_ha.h: This is a stubbed-out High Availability API. Much
more is needed for full HA support. See the
comments in the header and the description of what
is needed in the README.ctl.txt file for more
details.

ctl_io.h: This defines most of the core CTL I/O structures.
union ctl_io is conceptually very similar to CAM's
union ccb.

ctl_ioctl.h: This defines all ioctls available through the CTL
character device, and the data structures needed
for those ioctls.

ctl_mem_pool.c,
ctl_mem_pool.h: Generic memory pool implementation used by the
internal frontend.

ctl_private.h: Private data structres (e.g. CTL softc) and
function prototypes. This also includes the SCSI
vendor and product names used by CTL.

ctl_scsi_all.c,
ctl_scsi_all.h: CTL wrappers around CAM sense printing functions.

ctl_ser_table.c: Command serialization table. This defines what
happens when one type of command is followed by
another type of command.

ctl_util.c,
ctl_util.h: CTL utility functions, primarily designed to be
used from userland. See ctladm for the primary
consumer of these functions. These include CDB
building functions.

scsi_ctl.c: CAM target peripheral driver and CTL frontend port.
This is the path into CTL for commands from
target-capable hardware/SIMs.

README.ctl.txt: CTL code features, roadmap, to-do list.

usr.sbin/Makefile: Add ctladm.

ctladm/Makefile,
ctladm/ctladm.8,
ctladm/ctladm.c,
ctladm/ctladm.h,
ctladm/util.c: ctladm(8) is the CTL management utility.
It fills a role similar to camcontrol(8).
It allow configuring LUNs, issuing commands,
injecting errors and various other control
functions.

usr.bin/Makefile: Add ctlstat.

ctlstat/Makefile
ctlstat/ctlstat.8,
ctlstat/ctlstat.c: ctlstat(8) fills a role similar to iostat(8).
It reports I/O statistics for CTL.

sys/conf/files: Add CTL files.

sys/conf/NOTES: Add device ctl.

sys/cam/scsi_all.h: To conform to more recent specs, the inquiry CDB
length field is now 2 bytes long.

Add several mode page definitions for CTL.

sys/cam/scsi_all.c: Handle the new 2 byte inquiry length.

sys/dev/ciss/ciss.c,
sys/dev/ata/atapi-cam.c,
sys/cam/scsi/scsi_targ_bh.c,
scsi_target/scsi_cmds.c,
mlxcontrol/interface.c: Update for 2 byte inquiry length field.

scsi_da.h: Add versions of the format and rigid disk pages
that are in a more reasonable format for CTL.

amd64/conf/GENERIC,
i386/conf/GENERIC,
ia64/conf/GENERIC,
sparc64/conf/GENERIC: Add device ctl.

i386/conf/PAE: The CTL frontend SIM at least does not compile
cleanly on PAE.

Sponsored by: Copan Systems, SGI and Spectra Logic
MFC after: 1 month