Implement separate I/O dispatch method for ZVOLs in "dev" mode.
Unlike disk devices ZVOLs process all requests synchronously. That makes
impossible sending multiple requests to them from single thread. From the
other side ZVOLs have real d_read/d_write methods, which unlike d_strategy
can handle uio scatter/gather and have no strict I/O size limitations.
So, if ZVOL in "dev" mode is detected, use of d_read/d_write methods instead
of d_strategy allows to avoid pointless splitting of large requests into
MAXPHYS (128K) sized chunks.
Increase maximal number of SCSI ports in CTL from 32 to 128.
After I gave each iSCSI target its own port, the old limit appeared to be
not so big. This change almost proportionally increases per-LUN memory
use, but it is still three times better then it was before r268807.
Reduce per-LUN memory usage from 18MB to 1.8MB.
CTL never had use for CA support code since SPI has gone, and there is no
even frontends supporting that. But it still was reserving 256 bytes of
memory per LUN per every possible initiator on every possible port.
Wrap unused code with ifdef's in case somebody ever need it.
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!
Sponsored by: iXsystems, Inc.
Fix ctl(4) kldload failure that manifested like this:
link_elf_obj: symbol icl_pdu_new_bhs undefined
PR: 192031
Submitted by: Nils Beyer (earlier version)
Sponsored by: FreeBSD Foundation
>r267118 | imp | 2014-06-05 11:13:42 -0600 (Thu, 05 Jun 2014) | 9 lines
>The code that combines adjacent ranges for BIO_DELETEs to optimize
>trims to the device assumes the list is sorted. Don't apply the
>optimization of not sorting the queue when we have SSDs to the
>delete_queue, since it causes more discard traffic to the drive. While
>one could argue that the higher levels should coalesce the trims,
>that's not done today, so some optimization at this level is needed.
>CR: https://phabric.freebsd.org/D142
>r268205 | imp | 2014-07-02 23:22:13 -0600 (Wed, 02 Jul 2014) | 9 lines
>Rework the BIO_DELETE code slightly. Always queue the BIO_DELETE
>requests on the trim_queue, even for the CFA ERASE. This allows us, in
>the future, to collapse adjacent requests. Since CFA ERASE is only for
>CF cards, and it is so restrictive in what it can do, the collapse
>code is not presently here. This also brings the ada driver more in
>line with the da driver's treatment of BIO_DELETEs.
Add persistent reservation support to camcontrol(8).
camcontrol(8) now supports a new 'persist' subcommand that allows users to
issue SCSI PERSISTENT RESERVE IN / OUT commands.
Enable TAS feature: notify initiator if its command was aborted by other.
That should make operation more kind to multi-initiator environment.
Without this, other initiators may find out that something bad happened
to their commands only via command timeout.
Teach ctl_add_initiator() to dynamically allocate IIDs from pool.
If port passed negative IID value, the function will try to allocate IID
from the pool of unused, based on passed wwpn or name arguments. It does
all its best to make IID unique and persistent across reconnects.
This makes persistent reservation properly work for iSCSI. Previously,
in case of reconnects, reservation could be unexpectedly lost, or even
migrate between intiators.
When new connection comes in, check whether we already have session from
the same intiator (Name+ISID). If so -- terminate the old session and let
the new one take its place, as required by iSCSI RFC.
Implement ABORT TASK SET and I_T NEXUS RESET task management functions.
Use the last one to terminate active commands on iSCSI session termination.
Previous code was aborting only commands doing some data moves.
Close race in r268291 between port destruction, delayed by sessions
teardown, and new port creation during `service ctld restart`.
Close it by returning iSCSI port internal state, that allows to identify
dying ports, which should not be counted as existing, from really alive.
Move lun_map() method from command nexus to port.
Previous implementation made impossible to do some things, such as calling
it for ports other then one through which command arrived.
Pass through iSCSI session ISID from LOGIN request to the CTL frontend.
ISID is an important part of initiator transport ID for iSCSI. It is not
used now, but should be to properly implement persistent reservation.
Burry devid port method, which was a gross hack.
Instead make ports provide wanted port and target IDs, and LUNs provide
wanted LUN IDs. After that core Device ID VPD code only had to link all
of them together and add relative port and port group numbers.
LUN ID for iSCSI LUNs no longer created by CTL, but by ctld, and passed
to CTL as "scsiname" LUN option. This makes LUNs to report the same set
of IDs, independently from the port through which it is accessed, as
required by SCSI specifications.
Create separate CTL port for every iSCSI target (and maybe portal group).
Having single port for all iSCSI connections makes problematic implementing
some more advanced SCSI functionality in CTL, that require proper ports
enumeration and identification.
This change extends CTL iSCSI API, making ctld daemon to control list of
iSCSI ports in CTL. When new target is defined in config fine, ctld will
create respective port in CTL. When target is removed -- port will be
also removed after all active commands through that port properly aborted.
This change require ctld to be rebuilt to match the kernel.
As a minor side effect, this allows to have iSCSI targets without LUNs.
While that may look odd and not very useful, that is not incorrect.
Separate concepts of frontend and port.
Before iSCSI implementation CTL had no knowledge about frontend drivers,
it had only frontends, which really were ports (alike to LUNs, if comparing
to backends). But iSCSI added there ioctl() method, which does not belong
to frontend as a port, but belongs to a frontend driver.
Remove targ_enable()/targ_disable() frontend methods.
Those methods were never implemented, and I believe that their concept is
wrong, since single frontend (SCSI port) can not handle several targets.
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.
Increase CTL_DEVID_LEN from 16 to 64 bytes.
SPC-4 recommends T10 vendor ID based LUN ID was created by concatenating
product name and serial number (and istgt follows that). But product name
is 16 bytes long by itself, so 16 bytes total length is clearly not enough
to fit both.
To keep compatibility with existing configurations, pad short device IDs
to old length of 16, same as before.
This change probably breaks CTL user-level ABI, so control tools should
be rebuilt after this change.
Introduce fine-grained CTL locking to improve SMP scalability.
Split global ctl_lock, historically protecting most of CTL context:
- remaining ctl_lock now protects lists of fronends and backends;
- per-LUN lun_lock(s) protect LUN-specific information;
- per-thread queue_lock(s) protect request queues.
This allows to radically reduce congestion on ctl_lock.
Create multiple worker threads, depending on number of CPUs, and assign
each LUN to one of them. This allows to spread load between multiple CPUs,
still avoiging congestion on queues and LUNs locks.
On 40-core server, exporting 5 LUNs, each backed by gstripe of SATA SSDs,
accessed via 6 iSCSI connections, this change improves peak request rate
from 250K to 680K IOPS.
Sponsored by: iXsystems, Inc.
Simplify statistics calculation.
Instead of trying to guess size of disk I/O operations (it just won't work
that way for newly added commands, and is equal to data move size for old
ones), account data move traffic. If disk I/Os are that interesting, then
backends have to account and provide that information.
Block backend already exports the information about disk I/Os via devstat,
so having it here too is excessive.
Allow MODE SENSE commands through Write Exclusive persistent reservation,
as required by SPC-4.
Report that fact in persistent reservation capabilities.
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.
Add some more CTL_FLAG_ABORT check points.
This should allow to abort commands doing mostly disk I/O, such as VERIFY
or WRITE SAME. Before this change CTL_FLAG_ABORT was only checked around
data moves, which for these commands may not happen for a very long time.
