From bff9b33a3c4e0757c1e779ebedbffa391d926ecb Mon Sep 17 00:00:00 2001
From: Max Reitz <mreitz@redhat.com>
Date: Mon, 4 Nov 2013 22:31:52 +0100
Subject: [PATCH 01/87] block: drop bs_snapshots global variable
RH-Author: Max Reitz <mreitz@redhat.com>
Message-id: <1383604354-12743-2-git-send-email-mreitz@redhat.com>
Patchwork-id: 55301
O-Subject: [RHEL-7.0 qemu-kvm PATCH 01/43] block: drop bs_snapshots global variable
Bugzilla: 1026524
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
From: Stefan Hajnoczi <stefanha@redhat.com>
BZ: 1026524
The bs_snapshots global variable points to the BlockDriverState which
will be used to save vmstate. This is really a savevm.c concept but was
moved into block.c:bdrv_snapshots() when it became clear that hotplug
could result in a dangling pointer.
While auditing the block layer's global state I came upon bs_snapshots
and realized that a variable is not necessary here. Simply find the
first BlockDriverState capable of internal snapshots each time this is
needed.
The behavior of bdrv_snapshots() is preserved across hotplug because new
drives are always appended to the bdrv_states list. This means that
calling the new find_vmstate_bs() function is idempotent - it returns
the same BlockDriverState unless it was hot-unplugged.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 29d782710f87f01991bfc85cd9bef7d15280a5e2)
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
block.c | 28 ----------------------------
include/block/block.h | 1 -
savevm.c | 19 +++++++++++++++----
3 files changed, 15 insertions(+), 33 deletions(-)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
block.c | 28 ----------------------------
include/block/block.h | 1 -
savevm.c | 19 +++++++++++++++----
3 files changed, 15 insertions(+), 33 deletions(-)
diff --git a/block.c b/block.c
index fdff92f..84a3a8d 100644
--- a/block.c
+++ b/block.c
@@ -99,9 +99,6 @@ static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
static QLIST_HEAD(, BlockDriver) bdrv_drivers =
QLIST_HEAD_INITIALIZER(bdrv_drivers);
-/* The device to use for VM snapshots */
-static BlockDriverState *bs_snapshots;
-
/* If non-zero, use only whitelisted block drivers */
static int use_bdrv_whitelist;
@@ -1384,9 +1381,6 @@ void bdrv_close(BlockDriverState *bs)
notifier_list_notify(&bs->close_notifiers, bs);
if (bs->drv) {
- if (bs == bs_snapshots) {
- bs_snapshots = NULL;
- }
if (bs->backing_hd) {
bdrv_delete(bs->backing_hd);
bs->backing_hd = NULL;
@@ -1619,7 +1613,6 @@ void bdrv_delete(BlockDriverState *bs)
bdrv_close(bs);
- assert(bs != bs_snapshots);
g_free(bs);
}
@@ -1663,9 +1656,6 @@ void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops,
{
bs->dev_ops = ops;
bs->dev_opaque = opaque;
- if (bdrv_dev_has_removable_media(bs) && bs == bs_snapshots) {
- bs_snapshots = NULL;
- }
}
void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv,
@@ -3493,24 +3483,6 @@ int bdrv_is_snapshot(BlockDriverState *bs)
return !!(bs->open_flags & BDRV_O_SNAPSHOT);
}
-BlockDriverState *bdrv_snapshots(void)
-{
- BlockDriverState *bs;
-
- if (bs_snapshots) {
- return bs_snapshots;
- }
-
- bs = NULL;
- while ((bs = bdrv_next(bs))) {
- if (bdrv_can_snapshot(bs)) {
- bs_snapshots = bs;
- return bs;
- }
- }
- return NULL;
-}
-
int bdrv_snapshot_create(BlockDriverState *bs,
QEMUSnapshotInfo *sn_info)
{
diff --git a/include/block/block.h b/include/block/block.h
index bc1f5f6..3b3f40e 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -362,7 +362,6 @@ BlockInfo *bdrv_query_info(BlockDriverState *s);
BlockStats *bdrv_query_stats(const BlockDriverState *bs);
int bdrv_can_snapshot(BlockDriverState *bs);
int bdrv_is_snapshot(BlockDriverState *bs);
-BlockDriverState *bdrv_snapshots(void);
int bdrv_snapshot_create(BlockDriverState *bs,
QEMUSnapshotInfo *sn_info);
int bdrv_snapshot_goto(BlockDriverState *bs,
diff --git a/savevm.c b/savevm.c
index 1ed7f05..d9f3787 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2262,6 +2262,17 @@ out:
return ret;
}
+static BlockDriverState *find_vmstate_bs(void)
+{
+ BlockDriverState *bs = NULL;
+ while ((bs = bdrv_next(bs))) {
+ if (bdrv_can_snapshot(bs)) {
+ return bs;
+ }
+ }
+ return NULL;
+}
+
static int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
const char *name)
{
@@ -2338,7 +2349,7 @@ void do_savevm(Monitor *mon, const QDict *qdict)
}
}
- bs = bdrv_snapshots();
+ bs = find_vmstate_bs();
if (!bs) {
monitor_printf(mon, "No block device can accept snapshots\n");
return;
@@ -2440,7 +2451,7 @@ int load_vmstate(const char *name)
QEMUFile *f;
int ret;
- bs_vm_state = bdrv_snapshots();
+ bs_vm_state = find_vmstate_bs();
if (!bs_vm_state) {
error_report("No block device supports snapshots");
return -ENOTSUP;
@@ -2519,7 +2530,7 @@ void do_delvm(Monitor *mon, const QDict *qdict)
int ret;
const char *name = qdict_get_str(qdict, "name");
- bs = bdrv_snapshots();
+ bs = find_vmstate_bs();
if (!bs) {
monitor_printf(mon, "No block device supports snapshots\n");
return;
@@ -2551,7 +2562,7 @@ void do_info_snapshots(Monitor *mon, const QDict *qdict)
int *available_snapshots;
char buf[256];
- bs = bdrv_snapshots();
+ bs = find_vmstate_bs();
if (!bs) {
monitor_printf(mon, "No available block device supports snapshots\n");
return;
--
1.7.1