quorum: Create BDRVQuorumState and BlkDriver and do init.

Create the structure holding the quorum settings and write the minimal block
driver instanciation boilerplate.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
quorum: Add quorum_aio_writev and its dependencies.

Writes are mirrored num_children times on num_children devices.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
blkverify: Extract qemu_iovec_clone() and qemu_iovec_compare() from blkverify.

qemu_iovec_compare() will be used to compare IOs vectors in quorum blkverify
mode. The patch extracts these functions in order to factorize the code.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
quorum: Add quorum_aio_readv.

Add code to do num_children reads in parallel and cleanup the structures
afterwards.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
quorum: Add quorum mechanism.

This patchset enables the core of the quorum mechanism.
The num_children reads are compared to get the majority version and if this
version exists more than threshold times the guest won't see the error at all.

If a block is corrupted or if an error occurs during an IO or if the quorum
cannot be established QMP events are used to report to the management.

Use gnutls's SHA-256 to compare versions.

--enable-quorum must be used to enable the feature.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
quorum: Add quorum_getlength().

Check that every bs file returns the same length.
Otherwise, return -EIO to disable the quorum and
avoid length discrepancy.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
quorum: Add quorum_invalidate_cache().

We really want that live migration works with quorum so implement
quorum_invalidate_cache().

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
quorum: Add quorum_co_flush().

Makes a vote to select error if any.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
quorum: Implement recursive .bdrv_recurse_is_first_non_filter in quorum.

This is used to activate quorum snapshot.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
quorum: Add quorum_open() and quorum_close().

Example of command line:

-drive if=virtio,driver=quorum,\
children.0.file.filename=1.raw,\
children.0.node-name=1.raw,\
children.0.driver=raw,\
children.1.file.filename=2.raw,\
children.1.node-name=2.raw,\
children.1.driver=raw,\
children.2.file.filename=3.raw,\
children.2.node-name=3.raw,\
children.2.driver=raw,\
vote-threshold=2

blkverify=on with vote-threshold=2 and two files can be passed to
emulate blkverify.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
quorum: Add unit test.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
quorum: Simplify quorum_open()

Although it may not look like it, this patch simplifies quorum_open().
qdict_array_split() is now able to return QLists with different objects
than only QDicts, therefore it will now do all the work and
quorum_open() does not have to handle reference strings by itself.

This allows mixing full option dicts and reference strings for
specifying the child block devices of quorum; furthermore, it improves
handling of malformed specifications.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
iotests: Mixed quorum child device specifications

Add a test case to test 081 for mixing full option dicts and reference
strings of specifying the quorum child block devices through QMP.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
scsi: Change scsi sense buf size to 252

Current buffer size fails the assersion check in like

    hw/scsi/scsi-bus.c:1655:    assert(req->sense_len <= sizeof(req->sense));

when backend (block/iscsi.c) returns more data then 96.

Exercise the core dump path by booting an Gentoo ISO with scsi-generic
device backed with iscsi (built with libiscsi 1.7.0):

    x86_64-softmmu/qemu-system-x86_64 \
    -drive file=iscsi://localhost:3260/iqn.foobar/0,if=none,id=drive-disk \
    -device virtio-scsi-pci,id=scsi1,bus=pci.0,addr=0x6 \
    -device scsi-generic,drive=drive-disk,bus=scsi1.0,id=iscsi-disk \
    -boot d \
    -cdrom gentoo.iso

    qemu-system-x86_64: hw/scsi/scsi-bus.c:1655: scsi_req_complete:
    Assertion `req->sense_len <= sizeof(req->sense)' failed.

According to SPC-4, section 4.5.2.1, 252 is the limit of sense data. So
increase the value to fix it.

Also remove duplicated define for the macro.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
scsi: report thin provisioning errors with werror=report

SCSI defines a status code for when a thin-provisioned LUNs would
exceed the allocated space, map ENOSPC to it.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
scsi-bus: Fix transfer length for VERIFY with BYTCHK=11b

The transfer length depends on field BYTCHK, which is encoded in byte
1, bits 1..2.  However, the guard for for case BYTCHK=11b doesn't
work, and we get case 01b instead.  Fix it.

Note that since emulated scsi-hd fails the command outright, it takes
SCSI passthrough of a device that actually implements VERIFY with
BYTCHK=11b to make the bug bite.

Screwed up in commit d12ad44.  Spotted by Coverity.

Cc: qemu-stable@nongnu.org
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
block/iscsi: fix deadlock on scsi check condition

the retry logic was broken because the complete status
of the task structure was not reset. this resulted in
an infinite loop retrying the command over and over.

CC: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
block/iscsi: query for supported VPD pages

this patch ensures that we only query for block provisioning and
block limits vpd pages if they are advertised. It also cleans
up the inquiry code and eliminates some redundant code.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
scsi-disk: Add support for port WWN and index descriptors in VPD page 83h

To make a VM more convincing to my application, it's useful to be able
to add a port WWN and relative target port index to the descriptors
returned for VPD page 83h.  Add device properties to allow setting
these, and return them from INQUIRY commands.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
block/iscsi: fix segfault if writesame fails

commit fa6252b0 introduced a segfault because it tries
to read iTask.task->sense after iTask.task has been
freed.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>