75 lines
2.9 KiB
Diff
75 lines
2.9 KiB
Diff
From b1f0546548e561856252c2bc610a8f4f8fcdf007 Mon Sep 17 00:00:00 2001
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From: Stefano Garzarella <sgarzare@redhat.com>
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Date: Wed, 26 Jul 2023 09:48:07 +0200
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Subject: [PATCH 02/14] block/blkio: do not use open flags in qemu_open()
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Stefano Garzarella <sgarzare@redhat.com>
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RH-MergeRequest: 194: block/blkio: backport latest fixes for virtio-blk-* drivers
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RH-Bugzilla: 2225354 2225439
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RH-Acked-by: Hanna Czenczek <hreitz@redhat.com>
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RH-Acked-by: Alberto Faria <None>
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RH-Commit: [2/6] 1ccd0ef56182bb5e2374c3b5be98ee1ec05066d6 (sgarzarella/qemu-kvm-c-9-s)
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qemu_open() in blkio_virtio_blk_common_open() is used to open the
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character device (e.g. /dev/vhost-vdpa-0 or /dev/vfio/vfio) or in
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the future eventually the unix socket.
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In all these cases we cannot open the path in read-only mode,
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when the `read-only` option of blockdev is on, because the exchange
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of IOCTL commands for example will fail.
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In order to open the device read-only, we have to use the `read-only`
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property of the libblkio driver as we already do in blkio_file_open().
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Fixes: cad2ccc395 ("block/blkio: use qemu_open() to support fd passing for virtio-blk")
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Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2225439
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Reported-by: Qing Wang <qinwang@redhat.com>
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Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
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Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
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Message-id: 20230726074807.14041-1-sgarzare@redhat.com
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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(cherry picked from commit a5942c177b7bcc1357e496b7d68668befcfc2bb9)
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Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
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---
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block/blkio.c | 21 ++++++++++++---------
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1 file changed, 12 insertions(+), 9 deletions(-)
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diff --git a/block/blkio.c b/block/blkio.c
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index 3ea9841bd8..5a82c6cb1a 100644
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--- a/block/blkio.c
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+++ b/block/blkio.c
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@@ -685,15 +685,18 @@ static int blkio_virtio_blk_common_open(BlockDriverState *bs,
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* layer through the "/dev/fdset/N" special path.
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*/
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if (fd_supported) {
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- int open_flags;
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-
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- if (flags & BDRV_O_RDWR) {
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- open_flags = O_RDWR;
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- } else {
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- open_flags = O_RDONLY;
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- }
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-
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- fd = qemu_open(path, open_flags, errp);
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+ /*
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+ * `path` can contain the path of a character device
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+ * (e.g. /dev/vhost-vdpa-0 or /dev/vfio/vfio) or a unix socket.
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+ *
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+ * So, we should always open it with O_RDWR flag, also if BDRV_O_RDWR
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+ * is not set in the open flags, because the exchange of IOCTL commands
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+ * for example will fail.
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+ *
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+ * In order to open the device read-only, we are using the `read-only`
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+ * property of the libblkio driver in blkio_file_open().
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+ */
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+ fd = qemu_open(path, O_RDWR, errp);
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if (fd < 0) {
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return -EINVAL;
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}
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--
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2.39.3
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