block: freeze the backing chain earlier in stream_start()
commit20509c4b8b3fb2b058640d5f2e5f6d3527318792
authorAlberto Garcia <berto@igalia.com>
Thu, 28 Mar 2019 16:25:10 +0000 (28 18:25 +0200)
committerKevin Wolf <kwolf@redhat.com>
Tue, 2 Apr 2019 10:04:44 +0000 (2 12:04 +0200)
tree8a5c2082037c29eb699a628a37ffeb82bd8f1c6d
parent0f0998f6219b25f54f8ab20e3803eff552af3b9c
block: freeze the backing chain earlier in stream_start()

Commit 6585493369819a48d34a86d57ec6b97cb5cd9bc0 added code to freeze
the backing chain from 'top' to 'base' for the duration of the
block-stream job.

The problem is that the freezing happens too late in stream_start():
during the bdrv_reopen_set_read_only() call earlier in that function
another job can jump in and remove the base image. If that happens we
have an invalid chain and QEMU crashes.

This patch puts the bdrv_freeze_backing_chain() call at the beginning
of the function.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
block/stream.c