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authorMarkus Armbruster <armbru@redhat.com>2010-06-25 10:33:39 +0200
committerKevin Wolf <kwolf@redhat.com>2010-07-02 13:18:02 +0200
commitf9092b108f7b35e463e58bd3dd348ff002ba9e63 (patch)
treef2407ad08c49e3d15297af524e41b4c645d3d662 /savevm.c
parent8db520cee89bb84f21d107cea2d786894901bc54 (diff)
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savevm: Survive hot-unplug of snapshot device
savevm.c keeps a pointer to the snapshot block device. If you manage to get that device deleted, the pointer dangles, and the next snapshot operation will crash & burn. Unplugging a guest device that uses it does the trick: $ MALLOC_PERTURB_=234 qemu-system-x86_64 [...] QEMU 0.12.50 monitor - type 'help' for more information (qemu) info snapshots No available block device supports snapshots (qemu) drive_add auto if=none,file=tmp.qcow2 OK (qemu) device_add usb-storage,id=foo,drive=none1 (qemu) info snapshots Snapshot devices: none1 Snapshot list (from none1): ID TAG VM SIZE DATE VM CLOCK (qemu) device_del foo (qemu) info snapshots Snapshot devices: Segmentation fault (core dumped) Move management of that pointer to block.c, and zap it when the device it points becomes unusable. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'savevm.c')
-rw-r--r--savevm.c31
1 files changed, 4 insertions, 27 deletions
diff --git a/savevm.c b/savevm.c
index 20354a8..f1f450e 100644
--- a/savevm.c
+++ b/savevm.c
@@ -83,9 +83,6 @@
#include "qemu_socket.h"
#include "qemu-queue.h"
-/* point to the block driver where the snapshots are managed */
-static BlockDriverState *bs_snapshots;
-
#define SELF_ANNOUNCE_ROUNDS 5
#ifndef ETH_P_RARP
@@ -1575,26 +1572,6 @@ out:
return ret;
}
-static BlockDriverState *get_bs_snapshots(void)
-{
- BlockDriverState *bs;
-
- if (bs_snapshots)
- return bs_snapshots;
- /* FIXME what if bs_snapshots gets hot-unplugged? */
-
- bs = NULL;
- while ((bs = bdrv_next(bs))) {
- if (bdrv_can_snapshot(bs)) {
- goto ok;
- }
- }
- return NULL;
- ok:
- bs_snapshots = bs;
- return bs;
-}
-
static int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
const char *name)
{
@@ -1674,7 +1651,7 @@ void do_savevm(Monitor *mon, const QDict *qdict)
}
}
- bs = get_bs_snapshots();
+ bs = bdrv_snapshots();
if (!bs) {
monitor_printf(mon, "No block device can accept snapshots\n");
return;
@@ -1769,7 +1746,7 @@ int load_vmstate(const char *name)
}
}
- bs = get_bs_snapshots();
+ bs = bdrv_snapshots();
if (!bs) {
error_report("No block device supports snapshots");
return -EINVAL;
@@ -1833,7 +1810,7 @@ void do_delvm(Monitor *mon, const QDict *qdict)
int ret;
const char *name = qdict_get_str(qdict, "name");
- bs = get_bs_snapshots();
+ bs = bdrv_snapshots();
if (!bs) {
monitor_printf(mon, "No block device supports snapshots\n");
return;
@@ -1863,7 +1840,7 @@ void do_info_snapshots(Monitor *mon)
int nb_sns, i;
char buf[256];
- bs = get_bs_snapshots();
+ bs = bdrv_snapshots();
if (!bs) {
monitor_printf(mon, "No available block device supports snapshots\n");
return;