* [Qemu-devel] [PATCH v2 0/6] pr-manager/qemu-pr-helper patches for QEMU 3.0
@ 2018-06-28 19:57 Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 1/6] pr-helper: fix --socket-path default in help Paolo Bonzini
` (5 more replies)
0 siblings, 6 replies; 9+ messages in thread
From: Paolo Bonzini @ 2018-06-28 19:57 UTC (permalink / raw)
To: qemu-devel
The first three patches are more or less trivial bugfixes. The
last three allow libvirt to know the status of the qemu-pr-helper
process that is attached to a running QEMU instance.
Thanks,
Paolo
v1->v2: new patch for non-Linux portability
issue event as soon as the socket is disconnected
do not include full object path in event
renamed "is_connected" field to "connected"
Paolo Bonzini (6):
pr-helper: fix --socket-path default in help
pr-helper: fix assertion failure on failed multipath PERSISTENT
RESERVE IN
pr-manager-helper: avoid SIGSEGV when writing to the socket fail
pr-manager: put stubs in .c file
pr-manager: add query-pr-managers QMP command
pr-manager-helper: report event on connection/disconnection
include/scsi/pr-manager.h | 11 ++--------
qapi/block.json | 52 +++++++++++++++++++++++++++++++++++++++++++++++
scsi/Makefile.objs | 1 +
scsi/pr-manager-helper.c | 28 +++++++++++++++++++++++++
scsi/pr-manager-stub.c | 30 +++++++++++++++++++++++++++
scsi/pr-manager.c | 45 ++++++++++++++++++++++++++++++++++++++++
scsi/qemu-pr-helper.c | 21 +++++++++++--------
7 files changed, 171 insertions(+), 17 deletions(-)
create mode 100644 scsi/pr-manager-stub.c
--
1.8.3.1
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH 1/6] pr-helper: fix --socket-path default in help
2018-06-28 19:57 [Qemu-devel] [PATCH v2 0/6] pr-manager/qemu-pr-helper patches for QEMU 3.0 Paolo Bonzini
@ 2018-06-28 19:57 ` Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 2/6] pr-helper: fix assertion failure on failed multipath PERSISTENT RESERVE IN Paolo Bonzini
` (4 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Paolo Bonzini @ 2018-06-28 19:57 UTC (permalink / raw)
To: qemu-devel
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>
---
scsi/qemu-pr-helper.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/scsi/qemu-pr-helper.c b/scsi/qemu-pr-helper.c
index d0f8317..4057cf3 100644
--- a/scsi/qemu-pr-helper.c
+++ b/scsi/qemu-pr-helper.c
@@ -74,8 +74,16 @@ static int uid = -1;
static int gid = -1;
#endif
+static void compute_default_paths(void)
+{
+ if (!socket_path) {
+ socket_path = qemu_get_local_state_pathname("run/qemu-pr-helper.sock");
+ }
+}
+
static void usage(const char *name)
{
+ compute_default_paths();
(printf) (
"Usage: %s [OPTIONS] FILE\n"
"Persistent Reservation helper program for QEMU\n"
@@ -845,13 +853,6 @@ static const char *socket_activation_validate_opts(void)
return NULL;
}
-static void compute_default_paths(void)
-{
- if (!socket_path) {
- socket_path = qemu_get_local_state_pathname("run/qemu-pr-helper.sock");
- }
-}
-
static void termsig_handler(int signum)
{
atomic_cmpxchg(&state, RUNNING, TERMINATE);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH 2/6] pr-helper: fix assertion failure on failed multipath PERSISTENT RESERVE IN
2018-06-28 19:57 [Qemu-devel] [PATCH v2 0/6] pr-manager/qemu-pr-helper patches for QEMU 3.0 Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 1/6] pr-helper: fix --socket-path default in help Paolo Bonzini
@ 2018-06-28 19:57 ` Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 3/6] pr-manager-helper: avoid SIGSEGV when writing to the socket fail Paolo Bonzini
` (3 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Paolo Bonzini @ 2018-06-28 19:57 UTC (permalink / raw)
To: qemu-devel
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>
---
scsi/qemu-pr-helper.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/scsi/qemu-pr-helper.c b/scsi/qemu-pr-helper.c
index 4057cf3..0218d65 100644
--- a/scsi/qemu-pr-helper.c
+++ b/scsi/qemu-pr-helper.c
@@ -558,7 +558,11 @@ static int do_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
#ifdef CONFIG_MPATH
if (is_mpath(fd)) {
/* multipath_pr_in fills the whole input buffer. */
- return multipath_pr_in(fd, cdb, sense, data, *resp_sz);
+ int r = multipath_pr_in(fd, cdb, sense, data, *resp_sz);
+ if (r != GOOD) {
+ *resp_sz = 0;
+ }
+ return r;
}
#endif
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH 3/6] pr-manager-helper: avoid SIGSEGV when writing to the socket fail
2018-06-28 19:57 [Qemu-devel] [PATCH v2 0/6] pr-manager/qemu-pr-helper patches for QEMU 3.0 Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 1/6] pr-helper: fix --socket-path default in help Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 2/6] pr-helper: fix assertion failure on failed multipath PERSISTENT RESERVE IN Paolo Bonzini
@ 2018-06-28 19:57 ` Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 4/6] pr-manager: put stubs in .c file Paolo Bonzini
` (2 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Paolo Bonzini @ 2018-06-28 19:57 UTC (permalink / raw)
To: qemu-devel
When writing to the qemu-pr-helper socket failed, the persistent
reservation manager was correctly disconnecting the socket, but it
did not clear pr_mgr->ioc. So the rest of the code did not know
that the socket had been disconnected, accessed pr_mgr->ioc and
happily caused a crash.
To reproduce, it is enough to stop qemu-pr-helper between QEMU
startup and executing e.g. sg_persist -k /dev/sdb.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
scsi/pr-manager-helper.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/scsi/pr-manager-helper.c b/scsi/pr-manager-helper.c
index 82ff6b6..0c0fe38 100644
--- a/scsi/pr-manager-helper.c
+++ b/scsi/pr-manager-helper.c
@@ -71,6 +71,7 @@ static int pr_manager_helper_write(PRManagerHelper *pr_mgr,
if (n_written <= 0) {
assert(n_written != QIO_CHANNEL_ERR_BLOCK);
object_unref(OBJECT(pr_mgr->ioc));
+ pr_mgr->ioc = NULL;
return n_written < 0 ? -EINVAL : 0;
}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH 4/6] pr-manager: put stubs in .c file
2018-06-28 19:57 [Qemu-devel] [PATCH v2 0/6] pr-manager/qemu-pr-helper patches for QEMU 3.0 Paolo Bonzini
` (2 preceding siblings ...)
2018-06-28 19:57 ` [Qemu-devel] [PATCH 3/6] pr-manager-helper: avoid SIGSEGV when writing to the socket fail Paolo Bonzini
@ 2018-06-28 19:57 ` Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 5/6] pr-manager: add query-pr-managers QMP command Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 6/6] pr-manager-helper: report event on connection/disconnection Paolo Bonzini
5 siblings, 0 replies; 9+ messages in thread
From: Paolo Bonzini @ 2018-06-28 19:57 UTC (permalink / raw)
To: qemu-devel
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
include/scsi/pr-manager.h | 9 ---------
scsi/Makefile.objs | 1 +
scsi/pr-manager-stub.c | 24 ++++++++++++++++++++++++
3 files changed, 25 insertions(+), 9 deletions(-)
create mode 100644 scsi/pr-manager-stub.c
diff --git a/include/scsi/pr-manager.h b/include/scsi/pr-manager.h
index 5d2f13a..71971ae 100644
--- a/include/scsi/pr-manager.h
+++ b/include/scsi/pr-manager.h
@@ -41,15 +41,6 @@ BlockAIOCB *pr_manager_execute(PRManager *pr_mgr,
BlockCompletionFunc *complete,
void *opaque);
-#ifdef CONFIG_LINUX
PRManager *pr_manager_lookup(const char *id, Error **errp);
-#else
-static inline PRManager *pr_manager_lookup(const char *id, Error **errp)
-{
- /* The classes do not exist at all! */
- error_setg(errp, "No persistent reservation manager with id '%s'", id);
- return NULL;
-}
-#endif
#endif
diff --git a/scsi/Makefile.objs b/scsi/Makefile.objs
index 4d25e47..bb8789c 100644
--- a/scsi/Makefile.objs
+++ b/scsi/Makefile.objs
@@ -1,3 +1,4 @@
block-obj-y += utils.o
block-obj-$(CONFIG_LINUX) += pr-manager.o pr-manager-helper.o
+block-obj-$(call lnot,$(CONFIG_LINUX)) += pr-manager-stub.o
diff --git a/scsi/pr-manager-stub.c b/scsi/pr-manager-stub.c
new file mode 100644
index 0000000..632f17c
--- /dev/null
+++ b/scsi/pr-manager-stub.c
@@ -0,0 +1,24 @@
+/*
+ * Persistent reservation manager - stub for non-Linux platforms
+ *
+ * Copyright (c) 2018 Red Hat, Inc.
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This code is licensed under the LGPL.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "scsi/pr-manager.h"
+#include "trace.h"
+#include "qapi/qapi-types-block.h"
+#include "qapi/qapi-commands-block.h"
+
+PRManager *pr_manager_lookup(const char *id, Error **errp)
+{
+ /* The classes do not exist at all! */
+ error_setg(errp, "No persistent reservation manager with id '%s'", id);
+ return NULL;
+}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH 5/6] pr-manager: add query-pr-managers QMP command
2018-06-28 19:57 [Qemu-devel] [PATCH v2 0/6] pr-manager/qemu-pr-helper patches for QEMU 3.0 Paolo Bonzini
` (3 preceding siblings ...)
2018-06-28 19:57 ` [Qemu-devel] [PATCH 4/6] pr-manager: put stubs in .c file Paolo Bonzini
@ 2018-06-28 19:57 ` Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 6/6] pr-manager-helper: report event on connection/disconnection Paolo Bonzini
5 siblings, 0 replies; 9+ messages in thread
From: Paolo Bonzini @ 2018-06-28 19:57 UTC (permalink / raw)
To: qemu-devel
This command lets you query the connection status of each pr-manager-helper
object.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
include/scsi/pr-manager.h | 2 ++
qapi/block.json | 28 ++++++++++++++++++++++++++++
scsi/pr-manager-helper.c | 13 +++++++++++++
scsi/pr-manager-stub.c | 6 ++++++
scsi/pr-manager.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 94 insertions(+)
diff --git a/include/scsi/pr-manager.h b/include/scsi/pr-manager.h
index 71971ae..50a77b0 100644
--- a/include/scsi/pr-manager.h
+++ b/include/scsi/pr-manager.h
@@ -33,8 +33,10 @@ typedef struct PRManagerClass {
/* <public> */
int (*run)(PRManager *pr_mgr, int fd, struct sg_io_hdr *hdr);
+ bool (*is_connected)(PRManager *pr_mgr);
} PRManagerClass;
+bool pr_manager_is_connected(PRManager *pr_mgr);
BlockAIOCB *pr_manager_execute(PRManager *pr_mgr,
AioContext *ctx, int fd,
struct sg_io_hdr *hdr,
diff --git a/qapi/block.json b/qapi/block.json
index ca807f1..8765c29 100644
--- a/qapi/block.json
+++ b/qapi/block.json
@@ -78,6 +78,34 @@
'data': { 'device': 'str', 'name': 'str' } }
##
+# @PRManagerInfo:
+#
+# Information about a persistent reservation manager
+#
+# @id: the identifier of the persistent reservation manager
+#
+# @connected: true if the persistent reservation manager is connected to
+# the underlying storage or helper
+#
+# Since: 3.0
+##
+{ 'struct': 'PRManagerInfo',
+ 'data': {'id': 'str', 'connected': 'bool'} }
+
+##
+# @query-pr-managers:
+#
+# Returns a list of information about each persistent reservation manager.
+#
+# Returns: a list of @PRManagerInfo for each persistent reservation manager
+#
+# Since: 3.0
+##
+{ 'command': 'query-pr-managers', 'returns': ['PRManagerInfo'],
+ 'allow-preconfig': true }
+
+
+##
# @blockdev-snapshot-internal-sync:
#
# Synchronously take an internal snapshot of a block device, when the
diff --git a/scsi/pr-manager-helper.c b/scsi/pr-manager-helper.c
index 0c0fe38..b11481b 100644
--- a/scsi/pr-manager-helper.c
+++ b/scsi/pr-manager-helper.c
@@ -235,6 +235,18 @@ out:
return ret;
}
+static bool pr_manager_helper_is_connected(PRManager *p)
+{
+ PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(p);
+ bool result;
+
+ qemu_mutex_lock(&pr_mgr->lock);
+ result = (pr_mgr->ioc != NULL);
+ qemu_mutex_unlock(&pr_mgr->lock);
+
+ return result;
+}
+
static void pr_manager_helper_complete(UserCreatable *uc, Error **errp)
{
PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(uc);
@@ -284,6 +296,7 @@ static void pr_manager_helper_class_init(ObjectClass *klass,
&error_abort);
uc_klass->complete = pr_manager_helper_complete;
prmgr_klass->run = pr_manager_helper_run;
+ prmgr_klass->is_connected = pr_manager_helper_is_connected;
}
static const TypeInfo pr_manager_helper_info = {
diff --git a/scsi/pr-manager-stub.c b/scsi/pr-manager-stub.c
index 632f17c..738b6d7 100644
--- a/scsi/pr-manager-stub.c
+++ b/scsi/pr-manager-stub.c
@@ -22,3 +22,9 @@ PRManager *pr_manager_lookup(const char *id, Error **errp)
error_setg(errp, "No persistent reservation manager with id '%s'", id);
return NULL;
}
+
+
+PRManagerInfoList *qmp_query_pr_managers(Error **errp)
+{
+ return NULL;
+}
diff --git a/scsi/pr-manager.c b/scsi/pr-manager.c
index 87c45db..2a8f300 100644
--- a/scsi/pr-manager.c
+++ b/scsi/pr-manager.c
@@ -17,6 +17,10 @@
#include "block/thread-pool.h"
#include "scsi/pr-manager.h"
#include "trace.h"
+#include "qapi/qapi-types-block.h"
+#include "qapi/qapi-commands-block.h"
+
+#define PR_MANAGER_PATH "/objects"
typedef struct PRManagerData {
PRManager *pr_mgr;
@@ -64,6 +68,14 @@ BlockAIOCB *pr_manager_execute(PRManager *pr_mgr,
data, complete, opaque);
}
+bool pr_manager_is_connected(PRManager *pr_mgr)
+{
+ PRManagerClass *pr_mgr_class =
+ PR_MANAGER_GET_CLASS(pr_mgr);
+
+ return !pr_mgr_class->is_connected || pr_mgr_class->is_connected(pr_mgr);
+}
+
static const TypeInfo pr_manager_info = {
.parent = TYPE_OBJECT,
.name = TYPE_PR_MANAGER,
@@ -105,5 +117,38 @@ pr_manager_register_types(void)
type_register_static(&pr_manager_info);
}
+static int query_one_pr_manager(Object *object, void *opaque)
+{
+ PRManagerInfoList ***prev = opaque;
+ PRManagerInfoList *elem;
+ PRManagerInfo *info;
+ PRManager *pr_mgr;
+
+ pr_mgr = (PRManager *)object_dynamic_cast(object, TYPE_PR_MANAGER);
+ if (!pr_mgr) {
+ return 0;
+ }
+
+ elem = g_new0(PRManagerInfoList, 1);
+ info = g_new0(PRManagerInfo, 1);
+ info->id = object_get_canonical_path_component(object);
+ info->connected = pr_manager_is_connected(pr_mgr);
+ elem->value = info;
+ elem->next = NULL;
+
+ **prev = elem;
+ *prev = &elem->next;
+ return 0;
+}
+
+PRManagerInfoList *qmp_query_pr_managers(Error **errp)
+{
+ PRManagerInfoList *head = NULL;
+ PRManagerInfoList **prev = &head;
+ Object *container = container_get(object_get_root(), PR_MANAGER_PATH);
+
+ object_child_foreach(container, query_one_pr_manager, &prev);
+ return head;
+}
type_init(pr_manager_register_types);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [Qemu-devel] [PATCH 6/6] pr-manager-helper: report event on connection/disconnection
2018-06-28 19:57 [Qemu-devel] [PATCH v2 0/6] pr-manager/qemu-pr-helper patches for QEMU 3.0 Paolo Bonzini
` (4 preceding siblings ...)
2018-06-28 19:57 ` [Qemu-devel] [PATCH 5/6] pr-manager: add query-pr-managers QMP command Paolo Bonzini
@ 2018-06-28 19:57 ` Paolo Bonzini
2018-06-28 20:24 ` Eric Blake
5 siblings, 1 reply; 9+ messages in thread
From: Paolo Bonzini @ 2018-06-28 19:57 UTC (permalink / raw)
To: qemu-devel
Let management know if there were any problems communicating with
qemu-pr-helper. The event is edge-triggered, and is sent every time
the connection status of the pr-manager-helper object changes.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
qapi/block.json | 24 ++++++++++++++++++++++++
scsi/pr-manager-helper.c | 14 ++++++++++++++
2 files changed, 38 insertions(+)
diff --git a/qapi/block.json b/qapi/block.json
index 8765c29..11f01f2 100644
--- a/qapi/block.json
+++ b/qapi/block.json
@@ -359,6 +359,30 @@
'data': { 'device': 'str', 'id': 'str', 'tray-open': 'bool' } }
##
+# @PR_MANAGER_STATUS_CHANGED:
+#
+# Emitted whenever the connected status of a persistent reservation
+# manager changes.
+#
+# @id: The id of the PR manager object
+#
+# @connected: true if the PR manager is connected to a backend
+#
+# Since: 3.0
+#
+# Example:
+#
+# <- { "event": "PR_MANAGER_STATUS_CHANGED",
+# "data": { "id": "pr-helper0",
+# "connected": true
+# },
+# "timestamp": { "seconds": 1519840375, "microseconds": 450486 } }
+#
+##
+{ 'event': 'PR_MANAGER_STATUS_CHANGED',
+ 'data': { 'id': 'str', 'connected': 'bool' } }
+
+##
# @QuorumOpType:
#
# An enumeration of the quorum operation types
diff --git a/scsi/pr-manager-helper.c b/scsi/pr-manager-helper.c
index b11481b..519a296 100644
--- a/scsi/pr-manager-helper.c
+++ b/scsi/pr-manager-helper.c
@@ -17,6 +17,7 @@
#include "io/channel.h"
#include "io/channel-socket.h"
#include "pr-helper.h"
+#include "qapi/qapi-events-block.h"
#include <scsi/sg.h>
@@ -38,6 +39,16 @@ typedef struct PRManagerHelper {
QIOChannel *ioc;
} PRManagerHelper;
+static void pr_manager_send_status_changed_event(PRManagerHelper *pr_mgr)
+{
+ char *id = object_get_canonical_path_component(OBJECT(pr_mgr));
+
+ if (id) {
+ qapi_event_send_pr_manager_status_changed(id, !!pr_mgr->ioc,
+ &error_abort);
+ }
+}
+
/* Called with lock held. */
static int pr_manager_helper_read(PRManagerHelper *pr_mgr,
void *buf, int sz, Error **errp)
@@ -47,6 +58,7 @@ static int pr_manager_helper_read(PRManagerHelper *pr_mgr,
if (r < 0) {
object_unref(OBJECT(pr_mgr->ioc));
pr_mgr->ioc = NULL;
+ pr_manager_send_status_changed_event(pr_mgr);
return -EINVAL;
}
@@ -72,6 +84,7 @@ static int pr_manager_helper_write(PRManagerHelper *pr_mgr,
assert(n_written != QIO_CHANNEL_ERR_BLOCK);
object_unref(OBJECT(pr_mgr->ioc));
pr_mgr->ioc = NULL;
+ pr_manager_send_status_changed_event(pr_mgr);
return n_written < 0 ? -EINVAL : 0;
}
@@ -127,6 +140,7 @@ static int pr_manager_helper_initialize(PRManagerHelper *pr_mgr,
goto out_close;
}
+ pr_manager_send_status_changed_event(pr_mgr);
return 0;
out_close:
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH 6/6] pr-manager-helper: report event on connection/disconnection
2018-06-28 19:57 ` [Qemu-devel] [PATCH 6/6] pr-manager-helper: report event on connection/disconnection Paolo Bonzini
@ 2018-06-28 20:24 ` Eric Blake
2018-06-29 10:15 ` Paolo Bonzini
0 siblings, 1 reply; 9+ messages in thread
From: Eric Blake @ 2018-06-28 20:24 UTC (permalink / raw)
To: Paolo Bonzini, qemu-devel
On 06/28/2018 02:57 PM, Paolo Bonzini wrote:
> Let management know if there were any problems communicating with
> qemu-pr-helper. The event is edge-triggered, and is sent every time
> the connection status of the pr-manager-helper object changes.
Is this something that guest actions can intentionally trigger, and thus
cause a DoS attack by flooding the management app with events faster
than they can process? If so, this event should use rate-limiting.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> qapi/block.json | 24 ++++++++++++++++++++++++
> scsi/pr-manager-helper.c | 14 ++++++++++++++
> 2 files changed, 38 insertions(+)
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [Qemu-devel] [PATCH 6/6] pr-manager-helper: report event on connection/disconnection
2018-06-28 20:24 ` Eric Blake
@ 2018-06-29 10:15 ` Paolo Bonzini
0 siblings, 0 replies; 9+ messages in thread
From: Paolo Bonzini @ 2018-06-29 10:15 UTC (permalink / raw)
To: Eric Blake, qemu-devel
On 28/06/2018 22:24, Eric Blake wrote:
> On 06/28/2018 02:57 PM, Paolo Bonzini wrote:
>> Let management know if there were any problems communicating with
>> qemu-pr-helper. The event is edge-triggered, and is sent every time
>> the connection status of the pr-manager-helper object changes.
>
> Is this something that guest actions can intentionally trigger, and thus
> cause a DoS attack by flooding the management app with events faster
> than they can process?
No, unless they find a way to crash qemu-pr-helper and libvirt
immediately restarts it. If anything libvirt could throttle the restart
of the process, or ultimately not restart it at all, but I don't think
it's necessary.
Paolo
> If so, this event should use rate-limiting.
>
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>> qapi/block.json | 24 ++++++++++++++++++++++++
>> scsi/pr-manager-helper.c | 14 ++++++++++++++
>> 2 files changed, 38 insertions(+)
>
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2018-06-29 10:15 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-06-28 19:57 [Qemu-devel] [PATCH v2 0/6] pr-manager/qemu-pr-helper patches for QEMU 3.0 Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 1/6] pr-helper: fix --socket-path default in help Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 2/6] pr-helper: fix assertion failure on failed multipath PERSISTENT RESERVE IN Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 3/6] pr-manager-helper: avoid SIGSEGV when writing to the socket fail Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 4/6] pr-manager: put stubs in .c file Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 5/6] pr-manager: add query-pr-managers QMP command Paolo Bonzini
2018-06-28 19:57 ` [Qemu-devel] [PATCH 6/6] pr-manager-helper: report event on connection/disconnection Paolo Bonzini
2018-06-28 20:24 ` Eric Blake
2018-06-29 10:15 ` Paolo Bonzini
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