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author | Markus Armbruster <armbru@redhat.com> | 2010-06-25 10:33:39 +0200 |
---|---|---|
committer | Kevin Wolf <kwolf@redhat.com> | 2010-07-02 13:18:02 +0200 |
commit | f9092b108f7b35e463e58bd3dd348ff002ba9e63 (patch) | |
tree | f2407ad08c49e3d15297af524e41b4c645d3d662 /block.c | |
parent | 8db520cee89bb84f21d107cea2d786894901bc54 (diff) | |
download | qemu-f9092b108f7b35e463e58bd3dd348ff002ba9e63.zip qemu-f9092b108f7b35e463e58bd3dd348ff002ba9e63.tar.gz qemu-f9092b108f7b35e463e58bd3dd348ff002ba9e63.tar.bz2 |
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 'block.c')
-rw-r--r-- | block.c | 26 |
1 files changed, 26 insertions, 0 deletions
@@ -63,6 +63,9 @@ 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; @@ -629,6 +632,9 @@ unlink_and_fail: void bdrv_close(BlockDriverState *bs) { if (bs->drv) { + if (bs == bs_snapshots) { + bs_snapshots = NULL; + } if (bs->backing_hd) { bdrv_delete(bs->backing_hd); bs->backing_hd = NULL; @@ -677,6 +683,7 @@ void bdrv_delete(BlockDriverState *bs) bdrv_delete(bs->file); } + assert(bs != bs_snapshots); qemu_free(bs); } @@ -1778,6 +1785,25 @@ int bdrv_can_snapshot(BlockDriverState *bs) return 1; } +BlockDriverState *bdrv_snapshots(void) +{ + BlockDriverState *bs; + + if (bs_snapshots) + return bs_snapshots; + + bs = NULL; + while ((bs = bdrv_next(bs))) { + if (bdrv_can_snapshot(bs)) { + goto ok; + } + } + return NULL; + ok: + bs_snapshots = bs; + return bs; +} + int bdrv_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) { |