From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41168) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eKRwk-0002NE-Fc for qemu-devel@nongnu.org; Thu, 30 Nov 2017 11:44:23 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eKRwj-0000Zk-QB for qemu-devel@nongnu.org; Thu, 30 Nov 2017 11:44:22 -0500 From: Kevin Wolf Date: Thu, 30 Nov 2017 17:44:01 +0100 Message-Id: <20171130164401.29221-1-kwolf@redhat.com> Subject: [Qemu-devel] [PATCH] block: Formats don't need CONSISTENT_READ with NO_IO List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, mreitz@redhat.com, qemu-devel@nongnu.org Commit 1f4ad7d fixed 'qemu-img info' for raw images that are currently in use as a mirror target. It is not enough for image formats, though, as these still unconditionally request BLK_PERM_CONSISTENT_READ. As this permission is meaningless unless you do actual I/O on the image, drop the requirement and allow 'qemu-img info' even for image formats under conditions where BLK_PERM_CONSISTENT_READ can't be granted. Signed-off-by: Kevin Wolf --- block.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index 9a1a0d1e73..ddb6836c52 100644 --- a/block.c +++ b/block.c @@ -1924,6 +1924,8 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, assert(role == &child_backing || role == &child_file); if (!backing) { + int flags = bdrv_reopen_get_flags(reopen_queue, bs); + /* Apart from the modifications below, the same permissions are * forwarded and left alone as for filters */ bdrv_filter_default_perms(bs, c, role, reopen_queue, perm, shared, @@ -1936,7 +1938,9 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, /* bs->file always needs to be consistent because of the metadata. We * can never allow other users to resize or write to it. */ - perm |= BLK_PERM_CONSISTENT_READ; + if (!(flags & BDRV_O_NO_IO)) { + perm |= BLK_PERM_CONSISTENT_READ; + } shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); } else { /* We want consistent read from backing files if the parent needs it. -- 2.13.6