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authorKevin Wolf <kwolf@redhat.com>2023-12-01 15:25:18 +0100
committerKevin Wolf <kwolf@redhat.com>2023-12-21 22:49:27 +0100
commitd3007d348adaaf04ee8b099a475282034a662414 (patch)
tree15d0444ad44f4f6e9b1a59948907136b6c8e7f1e
parent6b5aa3a0fdfc74d42f9f7705fa6ced73253b06b1 (diff)
block: Fix crash when loading snapshot on inactive node
bdrv_is_read_only() only checks if the node is configured to be read-only eventually, but even if it returns false, writing to the node may not be permitted at the moment (because it's inactive). bdrv_is_writable() checks that the node can be written to right now, and this is what the snapshot operations really need. Change bdrv_can_snapshot() to use bdrv_is_writable() to fix crashes like the following: $ ./qemu-system-x86_64 -hda /tmp/test.qcow2 -loadvm foo -incoming defer qemu-system-x86_64: ../block/io.c:1990: int bdrv_co_write_req_prepare(BdrvChild *, int64_t, int64_t, BdrvTrackedRequest *, int): Assertion `!(bs->open_flags & BDRV_O_INACTIVE)' failed. The resulting error message after this patch isn't perfect yet, but at least it doesn't crash any more: $ ./qemu-system-x86_64 -hda /tmp/test.qcow2 -loadvm foo -incoming defer qemu-system-x86_64: Device 'ide0-hd0' is writable but does not support snapshots Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231201142520.32255-2-kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block/snapshot.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/block/snapshot.c b/block/snapshot.c
index ec8cf4810b..c4d40e80dd 100644
--- a/block/snapshot.c
+++ b/block/snapshot.c
@@ -196,8 +196,10 @@ bdrv_snapshot_fallback(BlockDriverState *bs)
int bdrv_can_snapshot(BlockDriverState *bs)
{
BlockDriver *drv = bs->drv;
+
GLOBAL_STATE_CODE();
- if (!drv || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
+
+ if (!drv || !bdrv_is_inserted(bs) || !bdrv_is_writable(bs)) {
return 0;
}