[libvirt] [PATCH 2/3] qemu: domain: Allow overriding images to read-write in qemuDomainStorageSourceAccessAllow

[Peter Krempa]

In commit 76b9aba2ba6 I refactored how the function treats the readonly
flag which introduced a bug when we'd not allow to force read-write
state for an image.

This created problems with blockjobs where we need to temporarily
override images to read-write.

Rename QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_READ_ONLY to
QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_OVERRIDE_READ_ONLY and also introduce
a complement QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_OVERRIDE_READ_WRITE which
will allow to force wire access.

https://bugzilla.redhat.com/show_bug.cgi?id=1717768

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 src/qemu/qemu_domain.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index e521bd3982..595150708b 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -9305,12 +9305,14 @@ typedef enum {
     QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_REVOKE = 1 << 0,
     /* operate on full backing chain rather than single image */
     QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_CHAIN = 1 << 1,
-    /* force permissions to read-only when allowing */
-    QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_READ_ONLY = 1 << 2,
+    /* force permissions to read-only/read-write when allowing */
+    /* currently does not properly wrok with QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_CHAIN */
+    QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_OVERRIDE_READ_ONLY = 1 << 2,
+    QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_OVERRIDE_READ_WRITE = 1 << 3,
     /* don't revoke permissions when modification has failed */
-    QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_SKIP_REVOKE = 1 << 3,
+    QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_SKIP_REVOKE = 1 << 4,
     /* VM already has access to the source and we are just modifying it */
-    QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_MODIFY_ACCESS = 1 << 4,
+    QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_MODIFY_ACCESS = 1 << 5,
 } qemuDomainStorageSourceAccessFlags;


@@ -9344,9 +9346,12 @@ qemuDomainStorageSourceAccessModify(virQEMUDriverPtr driver,
     bool revoke_namespace = false;
     bool revoke_lockspace = false;

-    if (flags & QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_READ_ONLY)
+    if (flags & QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_OVERRIDE_READ_ONLY)
         src->readonly = true;

+    if (flags & QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_OVERRIDE_READ_WRITE)
+        src->readonly = false;
+
     /* just tear down the disk access */
     if (flags & QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_REVOKE) {
         virErrorPreserveLast(&orig_err);
@@ -9491,7 +9496,9 @@ qemuDomainStorageSourceAccessAllow(virQEMUDriverPtr driver,
     qemuDomainStorageSourceAccessFlags flags = QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_SKIP_REVOKE;

     if (readonly)
-        flags |= QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_READ_ONLY;
+        flags |= QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_OVERRIDE_READ_ONLY;
+    else
+        flags |= QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_OVERRIDE_READ_WRITE;

     if (!newSource)
         flags |= QEMU_DOMAIN_STORAGE_SOURCE_ACCESS_MODIFY_ACCESS;
-- 
2.21.0