From 0b9e918f03df47ae393fa68d9ac37ce4820cbaaf Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Tue, 30 Jul 2019 15:37:08 +0200
Subject: [PATCH 1/2] fdc: Fix inserting read-only media in empty drive
In order to insert a read-only medium (i.e. a read-only block node) to
the BlockBackend of a floppy drive, we must not have taken write
permissions on that BlockBackend, or the operation will fail with the
error message "Block node is read-only".
The device already takes care to remove all permissions when the medium
is ejected, but the state isn't correct if the drive is initially empty:
It uses blk_is_read_only() to check whether write permissions should be
taken, but this function returns false for empty BlockBackends in the
common case.
Fix floppy_drive_realize() to avoid taking write permissions if the
drive is empty.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
---
hw/block/fdc.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/hw/block/fdc.c b/hw/block/fdc.c
index 77af9979de..9b24cb9b85 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -514,6 +514,7 @@ static void floppy_drive_realize(DeviceState *qdev, Error **errp)
FloppyDrive *dev = FLOPPY_DRIVE(qdev);
FloppyBus *bus = FLOPPY_BUS(qdev->parent_bus);
FDrive *drive;
+ bool read_only;
int ret;
if (dev->unit == -1) {
@@ -542,6 +543,12 @@ static void floppy_drive_realize(DeviceState *qdev, Error **errp)
dev->conf.blk = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
ret = blk_attach_dev(dev->conf.blk, qdev);
assert(ret == 0);
+
+ /* Don't take write permissions on an empty drive to allow attaching a
+ * read-only node later */
+ read_only = true;
+ } else {
+ read_only = !blk_bs(dev->conf.blk) || blk_is_read_only(dev->conf.blk);
}
blkconf_blocksizes(&dev->conf);
@@ -559,9 +566,7 @@ static void floppy_drive_realize(DeviceState *qdev, Error **errp)
dev->conf.rerror = BLOCKDEV_ON_ERROR_AUTO;
dev->conf.werror = BLOCKDEV_ON_ERROR_AUTO;
- if (!blkconf_apply_backend_options(&dev->conf,
- blk_is_read_only(dev->conf.blk),
- false, errp)) {
+ if (!blkconf_apply_backend_options(&dev->conf, read_only, false, errp)) {
return;
}
From 68174160144c9263366a4397ef8b417698e2735c Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Tue, 30 Jul 2019 16:50:52 +0200
Subject: [PATCH 2/2] iotests/118: Test inserting a read-only medium
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
---
tests/qemu-iotests/118 | 6 +++++-
tests/qemu-iotests/118.out | 4 ++--
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/tests/qemu-iotests/118 b/tests/qemu-iotests/118
index 603e10e8a2..499c5f0901 100755
--- a/tests/qemu-iotests/118
+++ b/tests/qemu-iotests/118
@@ -207,10 +207,11 @@ class GeneralChangeTestsBaseClass(ChangeBaseClass):
self.assert_qmp(result, 'return[0]/tray_open', False)
self.assert_qmp(result, 'return[0]/inserted/image/filename', new_img)
- def test_cycle(self):
+ def test_cycle(self, read_only_node=False):
result = self.vm.qmp('blockdev-add',
node_name='new',
driver=iotests.imgfmt,
+ read_only=read_only_node,
file={'filename': new_img,
'driver': 'file'})
self.assert_qmp(result, 'return', {})
@@ -257,6 +258,9 @@ class GeneralChangeTestsBaseClass(ChangeBaseClass):
self.assert_qmp(result, 'return[0]/tray_open', False)
self.assert_qmp(result, 'return[0]/inserted/image/filename', new_img)
+ def test_cycle_read_only_media(self):
+ self.test_cycle(True)
+
def test_close_on_closed(self):
result = self.vm.qmp('blockdev-close-tray', id=self.device_name)
# Should be a no-op
diff --git a/tests/qemu-iotests/118.out b/tests/qemu-iotests/118.out
index 6a917130b6..4823c113d5 100644
--- a/tests/qemu-iotests/118.out
+++ b/tests/qemu-iotests/118.out
@@ -1,5 +1,5 @@
-...........................................................
+...............................................................
----------------------------------------------------------------------
-Ran 59 tests
+Ran 63 tests
OK