From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44912) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cwUFD-0005u2-O7 for qemu-devel@nongnu.org; Fri, 07 Apr 2017 09:48:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cwUFC-0003Wc-TM for qemu-devel@nongnu.org; Fri, 07 Apr 2017 09:48:07 -0400 From: Kevin Wolf Date: Fri, 7 Apr 2017 15:47:42 +0200 Message-Id: <1491572865-8549-8-git-send-email-kwolf@redhat.com> In-Reply-To: <1491572865-8549-1-git-send-email-kwolf@redhat.com> References: <1491572865-8549-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 07/10] block: Don't check permissions for copy on read List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, qemu-devel@nongnu.org The assertion is currently failing. We can't require callers to have write permissions when all they are doing is a read, so comment it out. Add a FIXME comment in the code so that the check is re-enabled when copy on read is refactored into its own filter driver. Reported-by: Richard W.M. Jones Signed-off-by: Kevin Wolf Reviewed-by: Richard W.M. Jones --- block/io.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/block/io.c b/block/io.c index 2709a70..7321dda 100644 --- a/block/io.c +++ b/block/io.c @@ -945,7 +945,14 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, size_t skip_bytes; int ret; - assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE)); + /* FIXME We cannot require callers to have write permissions when all they + * are doing is a read request. If we did things right, write permissions + * would be obtained anyway, but internally by the copy-on-read code. As + * long as it is implemented here rather than in a separat filter driver, + * the copy-on-read code doesn't have its own BdrvChild, however, for which + * it could request permissions. Therefore we have to bypass the permission + * system for the moment. */ + // assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE)); /* Cover entire cluster so no additional backing file I/O is required when * allocating cluster in the image file. -- 1.8.3.1