|
 |
76daa3 |
From cda174ad842c9a61bc275315bf3155139ba19bc0 Mon Sep 17 00:00:00 2001
|
|
|
76daa3 |
From: John Snow <jsnow@redhat.com>
|
|
|
76daa3 |
Date: Thu, 11 May 2017 20:53:51 +0200
|
|
|
76daa3 |
Subject: [PATCH 1/5] blockdev: ignore aio=native for empty drives
|
|
|
76daa3 |
|
|
|
76daa3 |
RH-Author: John Snow <jsnow@redhat.com>
|
|
|
76daa3 |
Message-id: <20170511205351.6337-2-jsnow@redhat.com>
|
|
|
76daa3 |
Patchwork-id: 75070
|
|
|
76daa3 |
O-Subject: [RHV-7.4 qemu-kvm-rhev PATCH 1/1] blockdev: ignore aio=native for empty drives
|
|
|
76daa3 |
Bugzilla: 1402645
|
|
|
76daa3 |
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
|
|
|
76daa3 |
RH-Acked-by: Eric Blake <eblake@redhat.com>
|
|
|
76daa3 |
RH-Acked-by: Max Reitz <mreitz@redhat.com>
|
|
|
76daa3 |
|
|
|
76daa3 |
This is a bit of a gross one; Upstream QEMU changed the way it handles
|
|
|
76daa3 |
cache options with regards to removable media, associating options more
|
|
|
76daa3 |
with the medium instead of the device. As part of that, it became
|
|
|
76daa3 |
impossible to specify cache options on empty drives.
|
|
|
76daa3 |
|
|
|
76daa3 |
In the future, one would use blockdev-add instead to choose cache options
|
|
|
76daa3 |
per-medium instead of per-device, but we're not there yet in libvirt so
|
|
|
76daa3 |
we added a workaround downstream to simply ignore cache options on empty
|
|
|
76daa3 |
CDROMs under the premise of "It actually never worked anyway."
|
|
|
76daa3 |
|
|
|
76daa3 |
As fallout from this decision, it is now no longer possible to specify
|
|
|
76daa3 |
aio=native on empty CDROM devices either, as that requires the use of a
|
|
|
76daa3 |
cache option that you can no longer specify. As a bad, gross, disgusting
|
|
|
76daa3 |
workaround, simply ignore aio=native on empty drives until such time that
|
|
|
76daa3 |
libvirt stops providing such configurations.
|
|
|
76daa3 |
|
|
|
76daa3 |
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
|
|
|
76daa3 |
---
|
|
|
76daa3 |
blockdev.c | 17 ++++++++++++++++-
|
|
|
76daa3 |
1 file changed, 16 insertions(+), 1 deletion(-)
|
|
|
76daa3 |
|
|
|
76daa3 |
diff --git a/blockdev.c b/blockdev.c
|
|
|
76daa3 |
index a52e035..033c3fd 100644
|
|
|
76daa3 |
--- a/blockdev.c
|
|
|
76daa3 |
+++ b/blockdev.c
|
|
|
76daa3 |
@@ -474,6 +474,21 @@ static bool __redhat_com_has_bs_opts(QDict *bs_opts)
|
|
|
76daa3 |
return s != n;
|
|
|
76daa3 |
}
|
|
|
76daa3 |
|
|
|
76daa3 |
+/**
|
|
|
76daa3 |
+ * libvirt expects to be able to pass io driver options (aio=native) for CDROM
|
|
|
76daa3 |
+ * drives without inserted media. While this has worked historically, given the
|
|
|
76daa3 |
+ * above workaround and lack of a supported alternative in current versions of
|
|
|
76daa3 |
+ * libvirt, certain options such as aio=native cannot be supported as it
|
|
|
76daa3 |
+ * requires the use of an accompanying cache option, which we also ignore.
|
|
|
76daa3 |
+ * Until libvirt learns how to supply cache options to inserted media, ignore
|
|
|
76daa3 |
+ * the aio= preference on empty CDROMs with the understanding that un-tuned
|
|
|
76daa3 |
+ * performance is preferable to being unable to use the CDROM at all.
|
|
|
76daa3 |
+ */
|
|
|
76daa3 |
+static int __redhat_com_filter_flags(int flags)
|
|
|
76daa3 |
+{
|
|
|
76daa3 |
+ return flags & ~BDRV_O_NATIVE_AIO;
|
|
|
76daa3 |
+}
|
|
|
76daa3 |
+
|
|
|
76daa3 |
/* Takes the ownership of bs_opts */
|
|
|
76daa3 |
static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
|
|
|
76daa3 |
Error **errp)
|
|
|
76daa3 |
@@ -586,7 +601,7 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
|
|
|
76daa3 |
|
|
|
76daa3 |
blk = blk_new(0, BLK_PERM_ALL);
|
|
|
76daa3 |
blk_rs = blk_get_root_state(blk);
|
|
|
76daa3 |
- blk_rs->open_flags = bdrv_flags;
|
|
|
76daa3 |
+ blk_rs->open_flags = __redhat_com_filter_flags(bdrv_flags);
|
|
|
76daa3 |
blk_rs->read_only = read_only;
|
|
|
76daa3 |
blk_rs->detect_zeroes = detect_zeroes;
|
|
|
76daa3 |
|
|
|
76daa3 |
--
|
|
|
76daa3 |
1.8.3.1
|
|
|
76daa3 |
|