From 47357547c1040e029aec3e1d9e850d6249bc2bbb Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Mon, 15 Jan 2018 11:23:36 +0100 Subject: [PATCH 11/12] block: Don't request I/O permission with BDRV_O_NO_IO RH-Author: Kevin Wolf Message-id: <20180115112337.20885-3-kwolf@redhat.com> Patchwork-id: 78575 O-Subject: [RHV-7.5 qemu-kvm-rhev PATCH 2/3] block: Don't request I/O permission with BDRV_O_NO_IO Bugzilla: 1515604 RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Jeffrey Cody RH-Acked-by: John Snow 'qemu-img info' makes sense even when BLK_PERM_CONSISTENT_READ cannot be granted because of a block job in a running qemu process. It already sets BDRV_O_NO_IO to indicate that it doesn't access the guest visible data at all. Check the BDRV_O_NO_IO flags in blk_new_open(), so that I/O related permissions are not unnecessarily requested and 'qemu-img info' can work even if BLK_PERM_CONSISTENT_READ cannot be granted. Signed-off-by: Kevin Wolf Reviewed-by: Fam Zheng Reviewed-by: Alberto Garcia (cherry picked from commit 1f4ad7d3b8f7162ec0471506d86f57a5d77b8f76) Signed-off-by: Kevin Wolf Signed-off-by: Miroslav Rezanina --- block/block-backend.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index 083e65f..dce8b96 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -299,7 +299,7 @@ BlockBackend *blk_new_open(const char *filename, const char *reference, { BlockBackend *blk; BlockDriverState *bs; - uint64_t perm; + uint64_t perm = 0; /* blk_new_open() is mainly used in .bdrv_create implementations and the * tools where sharing isn't a concern because the BDS stays private, so we @@ -309,9 +309,11 @@ BlockBackend *blk_new_open(const char *filename, const char *reference, * caller of blk_new_open() doesn't make use of the permissions, but they * shouldn't hurt either. We can still share everything here because the * guest devices will add their own blockers if they can't share. */ - perm = BLK_PERM_CONSISTENT_READ; - if (flags & BDRV_O_RDWR) { - perm |= BLK_PERM_WRITE; + if ((flags & BDRV_O_NO_IO) == 0) { + perm |= BLK_PERM_CONSISTENT_READ; + if (flags & BDRV_O_RDWR) { + perm |= BLK_PERM_WRITE; + } } if (flags & BDRV_O_RESIZE) { perm |= BLK_PERM_RESIZE; -- 1.8.3.1