block/file-posix: Fix check_cache_dropped() error handling

The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.

check_cache_dropped() calls error_setg() in a loop.  It fails to break
the loop in one instance.  If a subsequent iteration error_setg()s
again, it trips error_setv()'s assertion.

Fix it to break the loop.

Fixes: 31be8a2a97ecba7d31a82932286489cac318e9e9
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200422130719.28225-3-armbru@redhat.com>

0 files changed, 0 insertions, 0 deletions