Commit Graph

30 Commits

Author SHA1 Message Date
Marc-André Lureau
1fbf2665e6 util: replace qemu_get_local_state_pathname()
Simplify the function to only return the directory path. Callers are
adjusted to use the GLib function to build paths, g_build_filename().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-39-marcandre.lureau@redhat.com>
2022-04-21 17:09:09 +04:00
Marc-André Lureau
49f9522193 include: rename qemu-common.h qemu/help-texts.h
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Warner Losh <imp@bsdimp.com>
Message-Id: <20220420132624.2439741-7-marcandre.lureau@redhat.com>
2022-04-21 16:58:24 +04:00
Richard Henderson
c5955f4ff4 util/log: Pass Error pointer to qemu_set_log
Do not force exit within qemu_set_log; return bool and pass
an Error value back up the stack as per usual.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-5-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Markus Armbruster
f9734d5d40 error: Use error_fatal to simplify obvious fatal errors (again)
We did this with scripts/coccinelle/use-error_fatal.cocci before, in
commit 50beeb6809 and 007b06578a.  This commit cleans up rarer
variations that don't seem worth matching with Coccinelle.

Cc: Thomas Huth <thuth@redhat.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Juan Quintela <quintela@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210720125408.387910-2-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2021-08-26 17:15:28 +02:00
Hannes Reinecke
a108557bbf scsi: inline sg_io_sense_from_errno() into the callers.
Currently sg_io_sense_from_errno() converts the two input parameters
'errno' and 'io_hdr' into sense code and SCSI status. Having
split the function off into scsi_sense_from_errno() and
scsi_sense_from_host_status(), both of which are available generically,
we now inline the logic in the callers so that scsi-disk and
scsi-generic will be able to pass host_status to the HBA.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Message-Id: <20201116184041.60465-7-hare@suse.de>
[Put together from "scsi-disk: Add sg_io callback to evaluate status"
 and what remains of "scsi: split sg_io_sense_from_errno() in two functions",
 with many other fixes. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-03-06 11:42:56 +01:00
Paolo Bonzini
92eecfff32 trace: remove argument from trace_init_file
It is not needed, all the callers are just saving what was
retrieved from -trace and trace_init_file can retrieve it
on its own.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20201102115841.4017692-1-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-11-11 13:08:09 +00:00
Stefan Hajnoczi
d73415a315 qemu/atomic.h: rename atomic_ to qatomic_
clang's C11 atomic_fetch_*() functions only take a C11 atomic type
pointer argument. QEMU uses direct types (int, etc) and this causes a
compiler error when a QEMU code calls these functions in a source file
that also included <stdatomic.h> via a system header file:

  $ CC=clang CXX=clang++ ./configure ... && make
  ../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid)

Avoid using atomic_*() names in QEMU's atomic.h since that namespace is
used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h
and <stdatomic.h> can co-exist. I checked /usr/include on my machine and
searched GitHub for existing "qatomic_" users but there seem to be none.

This patch was generated using:

  $ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \
    sort -u >/tmp/changed_identifiers
  $ for identifier in $(</tmp/changed_identifiers); do
        sed -i "s%\<$identifier\>%q$identifier%g" \
            $(git grep -I -l "\<$identifier\>")
    done

I manually fixed line-wrap issues and misaligned rST tables.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200923105646.47864-1-stefanha@redhat.com>
2020-09-23 16:07:44 +01:00
Markus Armbruster
5217f1887a error: Use error_reportf_err() where appropriate
Replace

    error_report("...: %s", ..., error_get_pretty(err));

by

    error_reportf_err(err, "...: ", ...);

One of the replaced messages lacked a colon.  Add it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200505101908.6207-6-armbru@redhat.com>
2020-05-27 07:45:30 +02:00
Christophe de Dinechin
4ce1e15fbc scsi/qemu-pr-helper: Fix out-of-bounds access to trnptid_list[]
Compile error reported by gcc 10.0.1:

scsi/qemu-pr-helper.c: In function ‘multipath_pr_out’:
scsi/qemu-pr-helper.c:523:32: error: array subscript <unknown> is outside array bounds of ‘struct transportid *[0]’ [-Werror=array-bounds]
  523 |             paramp.trnptid_list[paramp.num_transportid++] = id;
      |             ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from scsi/qemu-pr-helper.c:36:
/usr/include/mpath_persist.h:168:22: note: while referencing ‘trnptid_list’
  168 |  struct transportid *trnptid_list[];
      |                      ^~~~~~~~~~~~
scsi/qemu-pr-helper.c:424:35: note: defined here ‘paramp’
  424 |     struct prout_param_descriptor paramp;
      |                                   ^~~~~~

This highlights an actual implementation issue in function multipath_pr_out.
The variable paramp is declared with type `struct prout_param_descriptor`,
which is a struct terminated by an empty array in mpath_persist.h:

        struct transportid *trnptid_list[];

That empty array was filled with code that looked like that:

        trnptid_list[paramp.descr.num_transportid++] = id;

This is an actual out-of-bounds access.

The fix is to malloc `paramp`.

Signed-off-by: Christophe de Dinechin <dinechin@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 22:07:24 +01:00
Paolo Bonzini
a358bca240 build: rename CONFIG_LIBCAP to CONFIG_LIBCAP_NG
Since we are actually testing for the newer capng library, rename the
symbol to match.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-12-17 19:35:47 +01:00
Maxim Levitsky
b2aca78cb2 qemu-pr-helper: fix crash in mpath_reconstruct_sense
The 'r' variable was accidently shadowed, and because of this
we were always passing 0 to mpath_generic_sense, instead of original
return value, which triggers an abort()

This is an attempt to fix the
https://bugzilla.redhat.com/show_bug.cgi?id=1720047
although there might be other places in the code
that trigger qemu-pr-helper crash, and this fix might
not be the root cause.

The crash was reproduced by creating an iscsi target on a test machine,
and passing it twice to the guest like that:

-blockdev node-name=idisk0,driver=iscsi,transport=...,target=...
-device scsi-block,drive=idisk0,bus=scsi0.0,bootindex=-1,scsi-id=1,lun=0,share-rw=on
-device scsi-block,drive=idisk0,bus=scsi0.0,bootindex=-1,scsi-id=1,lun=1,share-rw=on

Then in the guest, both /dev/sda and /dev/sdb were aggregated by multipath to /dev/mpatha,
which was passed to a nested guest like that

-object pr-manager-helper,id=qemu_pr_helper,path=/root/work/vm/testvm/.run/pr_helper.socket
-blockdev node-name=test,driver=host_device,filename=/dev/mapper/mpatha,pr-manager=qemu_pr_helper
-device scsi-block,drive=test,bus=scsi0.0,bootindex=-1,scsi-id=0,lun=0

The nested guest run:

sg_persist --no-inquiry  -v --out --register --param-sark 0x1234 /dev/sda

Strictly speaking this is wrong configuration since qemu is where
the multipath was split, and thus the iscsi target was not aware of
multipath, and thus when libmpathpersist code rightfully tried to register
the PR key on all paths, it failed to do so.

However qemu-pr-helper should not crash in this case.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-10-03 12:58:02 +02:00
Juan Quintela
4e2d8bf6f1 socket: Add num connections to qio_channel_socket_sync()
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2019-09-03 23:24:42 +02:00
Markus Armbruster
a8d2532645 Include qemu-common.h exactly where needed
No header includes qemu-common.h after this commit, as prescribed by
qemu-common.h's file comment.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-5-armbru@redhat.com>
[Rebased with conflicts resolved automatically, except for
include/hw/arm/xlnx-zynqmp.h hw/arm/nrf51_soc.c hw/arm/msf2-soc.c
block/qcow2-refcount.c block/qcow2-cluster.c block/qcow2-cache.c
target/arm/cpu.h target/lm32/cpu.h target/m68k/cpu.h target/mips/cpu.h
target/moxie/cpu.h target/nios2/cpu.h target/openrisc/cpu.h
target/riscv/cpu.h target/tilegx/cpu.h target/tricore/cpu.h
target/unicore32/cpu.h target/xtensa/cpu.h; bsd-user/main.c and
net/tap-bsd.c fixed up]
2019-06-12 13:20:20 +02:00
Markus Armbruster
0b8fa32f55 Include qemu/module.h where needed, drop it from qemu-common.h
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-4-armbru@redhat.com>
[Rebased with conflicts resolved automatically, except for
hw/usb/dev-hub.c hw/misc/exynos4210_rng.c hw/misc/bcm2835_rng.c
hw/misc/aspeed_scu.c hw/display/virtio-vga.c hw/arm/stm32f205_soc.c;
ui/cocoa.m fixed up]
2019-06-12 13:18:33 +02:00
Christophe Fergeau
f5852efa29 log: Make glib logging go through QEMU
This commit adds a error_init() helper which calls
g_log_set_default_handler() so that glib logs (g_log, g_warning, ...)
are handled similarly to other QEMU logs. This means they will get a
timestamp if timestamps are enabled, and they will go through the
HMP monitor if one is configured.

This commit also adds a call to error_init() to the binaries
installed by QEMU. Since error_init() also calls error_set_progname(),
this means that *-linux-user, *-bsd-user and qemu-pr-helper messages
output with error_report, info_report, ... will slightly change: they
will be prefixed by the binary name.

glib debug messages are enabled through G_MESSAGES_DEBUG similarly to
the glib default log handler.

At the moment, this change will mostly impact SPICE logging if your
spice version is >= 0.14.1. With older spice versions, this is not going
to work as expected, but will not have any ill effect, so this call is
not conditional on the SPICE version.

Signed-off-by: Christophe Fergeau <cfergeau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20190131164614.19209-3-cfergeau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2019-04-17 19:08:27 +02:00
John Snow
039d4e3df0 scsi: Address spurious clang warning
Some versions of Clang prior to 6.0 (and some builds of clang after,
such as 6.0.1-2.fc28) fail to recognize { 0 } as a valid initializer
for a struct with subobjects when -Wmissing-braces is enabled.

https://bugs.llvm.org/show_bug.cgi?id=21689 and
https://reviews.llvm.org/rL314499 suggests this should be fixed in 6.0,
but it might not be the case for older versions or downstream versions.

For now, follow the precedent of ebf2a499 and replace the standard { 0 }
with the accepted { } to silence this warning and allow the build to
work under clang 6.0.1-2.fc28, and builds prior to 6.0.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20181127184929.20065-1-jsnow@redhat.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-11-27 23:56:12 +00:00
Marc-André Lureau
9e6bdef224 util: add qemu_write_pidfile()
There are variants of qemu_create_pidfile() in qemu-pr-helper and
qemu-ga. Let's have a common implementation in libqemuutil.

The code is initially based from pr-helper write_pidfile(), with
various improvements and suggestions from Daniel Berrangé:

  QEMU will leave the pidfile existing on disk when it exits which
  initially made me think it avoids the deletion race. The app
  managing QEMU, however, may well delete the pidfile after it has
  seen QEMU exit, and even if the app locks the pidfile before
  deleting it, there is still a race.

  eg consider the following sequence

        QEMU 1        libvirtd        QEMU 2

  1.    lock(pidfile)

  2.    exit()

  3.                 open(pidfile)

  4.                 lock(pidfile)

  5.                                  open(pidfile)

  6.                 unlink(pidfile)

  7.                 close(pidfile)

  8.                                  lock(pidfile)

  IOW, at step 8 the new QEMU has successfully acquired the lock, but
  the pidfile no longer exists on disk because it was deleted after
  the original QEMU exited.

  While we could just say no external app should ever delete the
  pidfile, I don't think that is satisfactory as people don't read
  docs, and admins don't like stale pidfiles being left around on
  disk.

  To make this robust, I think we might want to copy libvirt's
  approach to pidfile acquisition which runs in a loop and checks that
  the file on disk /after/ acquiring the lock matches the file that
  was locked. Then we could in fact safely let QEMU delete its own
  pidfiles on clean exit..

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180831145314.14736-2-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-02 18:47:55 +02:00
Murilo Opsfelder Araujo
1b0578f5c4 qemu-pr-helper: Fix build on CentOS 7
After commit b3f1c8c413 "qemu-pr-helper: use new
libmultipath API", QEMU started using new libmultipath API, which is not
available on CentOS 7.x.

This fixes that by probing the new libmultipath API in configure.  If it fails,
then try probing the old API.  If it fails, then consider libmultipath not
available.

With this, configure script defines CONFIG_MPATH_NEW_API that is used in
scsi/qemu-pr-helper.c to use the new libmultipath API.

Fixes: b3f1c8c413
BugLink: https://bugs.launchpad.net/qemu/+bug/1786343
Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Message-Id: <20180810141116.24016-1-muriloo@linux.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-08-23 13:32:50 +02:00
Michal Privoznik
2729d79d49 pr-helper: Rework socket path handling
When reviewing Paolo's pr-helper patches I've noticed couple of
problems:

1) socket_path needs to be calculated at two different places
(one for printing out help, the other if socket activation is NOT
used),

2) even though the default socket_path is allocated in
compute_default_paths() it is the only default path the function
handles. For instance, pidfile is allocated outside of this
function. And yet again, at different places than 1)

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Message-Id: <c791ba035f26ea957e8f3602e3009b621769b1ba.1530611283.git.mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-07-06 18:39:19 +02:00
Paolo Bonzini
ee8c13b814 pr-helper: avoid error on PR IN command with zero request size
After reading a PR IN command with zero request size in prh_read_request,
the resp->result field will be uninitialized and the resp.sz field will
be also uninitialized when returning to prh_co_entry.

If resp->result == GOOD (from a previous successful reply or just luck),
then the assert in prh_write_response might not be triggered and
uninitialized response will be sent.

The fix is to remove the whole handling of sz == 0 in prh_co_entry.
Those errors apply only to PR OUT commands and it's perfectly okay to
catch them later in do_pr_out and multipath_pr_out; the check for
too-short parameters in fact doesn't apply in the easy SG_IO case, as
it can be left to the target firmware even.

The result is that prh_read_request does not fail requests anymore and
prh_co_entry becomes simpler.

Reported-by: Dima Stepanov <dimastep@yandex-team.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-07-06 18:39:19 +02:00
Paolo Bonzini
86933b4e78 pr-helper: fix assertion failure on failed multipath PERSISTENT RESERVE IN
The response size is expected to be zero if the SCSI status is not
"GOOD", but nothing was resetting it.

This can be reproduced simply by "sg_persist -s /dev/sdb" where /dev/sdb
in the guest is a scsi-block device corresponding to a multipath device
on the host.

Before:

  PR in (Read full status): Aborted command

and on the host:

  prh_write_response: Assertion `resp->sz == 0' failed.

After:

  PR in (Read full status): bad field in cdb or parameter list
  (perhaps unsupported service action)

Reported-by: Jiri Belka <jbelka@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2018-06-28 19:05:35 +02:00
Paolo Bonzini
50fa332516 pr-helper: fix --socket-path default in help
Currently --help shows "(default '(null)')" for the -k/--socket-path
option.  Fix it by getting the default path in /var/run.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2018-06-28 19:05:34 +02:00
Michal Privoznik
bd6b1c8324 qemu-pr-helper: Write pidfile more often
Let's write pidfile even if user did not request --daemon but
they requested just --pidfile. Libvirt will use exactly this.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-04-09 16:36:40 +02:00
Michal Privoznik
8dc0bf2647 qemu-pr-helper: Daemonize before dropping privileges
After we've dropped privileges it might be not possible to write
pidfile. For instance, if this binary is run as root (because
user wants it to write pidfile to some privileged location)
writing pidfile fails because privileges are dropped before we
even get to that.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-04-09 16:36:40 +02:00
Michal Privoznik
f8e1a98964 qemu-pr-helper: Actually allow users to specify pidfile
Due to wrong specification of arguments to getopt_long() any
attempt to set pidfile resulted in:

1) the default to be leaked
2) the @pidfile variable to be set to NULL (because optarg is
NULL without this patch).

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Message-Id: <6f10cd53d361a395aa0e85a9311ec4e9a8fc11e5.1521868451.git.mprivozn@redhat.com>
Cc: qemu-stable@nongnu.org
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-03-26 14:37:15 +02:00
Thomas Huth
7e563bfb8a Polish the version strings containing the package version
Since commit 67a1de0d19 there is no space anymore between the
version number and the parentheses when running configure with
--with-pkgversion=foo :

 $ qemu-system-s390x --version
 QEMU emulator version 2.11.50(foo)

But the space is included when building without that option
when building from a git checkout:

 $ qemu-system-s390x --version
 QEMU emulator version 2.11.50 (v2.11.0-1494-gbec9c64-dirty)

The same confusion exists with the "query-version" QMP command.
Let's fix this by introducing a proper QEMU_FULL_VERSION definition
that includes the space and parentheses, while the QEMU_PKGVERSION
should just cleanly contain the package version string itself.
Note that this also changes the behavior of the "query-version" QMP
command (the space and parentheses are not included there anymore),
but that's supposed to be OK since the strings there are not meant
to be parsed by other tools.

Fixes: 67a1de0d19
Buglink: https://bugs.launchpad.net/qemu/+bug/1673373
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1518692807-25859-1-git-send-email-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-03-12 16:12:47 +01:00
Paolo Bonzini
a4a9b6eaf3 qemu-pr-helper: miscellaneous fixes
1) Return a generic sense if TEST UNIT READY does not provide one;

2) Fix two mistakes in copying from the spec.

Cc: qemu-stable@nongnu.org
Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-12-20 22:29:26 +01:00
Paolo Bonzini
b3f1c8c413 qemu-pr-helper: use new libmultipath API
libmultipath has recently changed its API.  The new API supports multi-threaded
clients better.  Unfortunately there is no backwards-compatibility, so we just
switch to the new one.  Running QEMU compiled with the new library on the old
library will likely crash, while doing the opposite will cause QEMU not to
start at all (because udev, get_multipath_config and put_multipath_config
are undefined).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-10-18 10:15:09 +02:00
Paolo Bonzini
fe8fc5ae5c scsi: add multipath support to qemu-pr-helper
Proper support of persistent reservation for multipath devices requires
communication with the multipath daemon, so that the reservation is
registered and applied when a path comes up.  The device mapper
utilities provide a library to do so; this patch makes qemu-pr-helper.c
detect multipath devices and, when one is found, delegate the operation
to libmpathpersist.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-22 21:07:27 +02:00
Paolo Bonzini
b855f8d175 scsi: build qemu-pr-helper
Introduce a privileged helper to run persistent reservation commands.
This lets virtual machines send persistent reservations without using
CAP_SYS_RAWIO or out-of-tree patches.  The helper uses Unix permissions
and SCM_RIGHTS to restrict access to processes that can access its socket
and prove that they have an open file descriptor for a raw SCSI device.

The next patch will also correct the usage of persistent reservations
with multipath devices.

It would also be possible to support for Linux's IOC_PR_* ioctls in
the future, to support NVMe devices.  For now, however, only SCSI is
supported.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-22 21:07:24 +02:00