From 2cc49072ced64daa446a90b802191496b4d28e69 Mon Sep 17 00:00:00 2001

Message-Id: <2cc49072ced64daa446a90b802191496b4d28e69@dist-git>

From: Michal Privoznik <mprivozn@redhat.com>

Date: Thu, 11 May 2017 15:38:37 +0200

Subject: [PATCH] qemuDomainBuildNamespace: Move /dev/* mountpoints later

https://bugzilla.redhat.com/show_bug.cgi?id=1449510

When setting up mount namespace for a qemu domain the following

steps are executed:

1) get list of mountpoints under /dev/

2) move them to /var/run/libvirt/qemu/$domName.ext

3) start constructing new device tree under /var/run/libvirt/qemu/$domName.dev

4) move the mountpoint of the new device tree to /dev

5) restore original mountpoints from step 2)

Note the problem with this approach is that if some device in step

3) requires access to a mountpoint from step 2) it will fail as

the mountpoint is not there anymore. For instance consider the

following domain disk configuration:

    <disk type='file' device='disk'>

      <driver name='qemu' type='raw'/>

      <source file='/dev/shm/vhostmd0'/>

      <target dev='vdb' bus='virtio'/>

      <address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/>

    </disk>

In this case operation fails as we are unable to create vhostmd0

in the new device tree because after step 2) there is no /dev/shm

anymore. Leave aside fact that we shouldn't try to create devices

living in other mountpoints. That's a separate bug that will be

addressed later.

Currently, the order described above is rearranged to:

1) get list of mountpoints under /dev/

2) start constructing new device tree under /var/run/libvirt/qemu/$domName.dev

3) move them to /var/run/libvirt/qemu/$domName.ext

4) move the mountpoint of the new device tree to /dev

5) restore original mountpoints from step 3)

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

Reviewed-by: Cedric Bosdonnat <cbosdonnat@suse.com>

(cherry picked from commit a7cc039dc796f541793955598377807af48341fb)

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 src/qemu/qemu_domain.c | 48 ++++++++++++++++++++++++------------------------

 1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c

index 2790d7e74..fbb65fab4 100644

--- a/src/qemu/qemu_domain.c

+++ b/src/qemu/qemu_domain.c

@@ -8026,6 +8026,30 @@ qemuDomainBuildNamespace(virQEMUDriverConfigPtr cfg,

     if (qemuDomainSetupDev(cfg, mgr, vm, devPath) < 0)

         goto cleanup;

+    if (qemuDomainSetupAllDisks(cfg, vm, devPath) < 0)

+        goto cleanup;

+

+    if (qemuDomainSetupAllHostdevs(cfg, vm, devPath) < 0)

+        goto cleanup;

+

+    if (qemuDomainSetupAllMemories(cfg, vm, devPath) < 0)

+        goto cleanup;

+

+    if (qemuDomainSetupAllChardevs(cfg, vm, devPath) < 0)

+        goto cleanup;

+

+    if (qemuDomainSetupTPM(cfg, vm, devPath) < 0)

+        goto cleanup;

+

+    if (qemuDomainSetupAllGraphics(cfg, vm, devPath) < 0)

+        goto cleanup;

+

+    if (qemuDomainSetupAllInputs(cfg, vm, devPath) < 0)

+        goto cleanup;

+

+    if (qemuDomainSetupAllRNGs(cfg, vm, devPath) < 0)

+        goto cleanup;

+

     /* Save some mount points because we want to share them with the host */

     for (i = 0; i < ndevMountsPath; i++) {

         struct stat sb;

@@ -8053,30 +8077,6 @@ qemuDomainBuildNamespace(virQEMUDriverConfigPtr cfg,

             goto cleanup;

     }

-    if (qemuDomainSetupAllDisks(cfg, vm, devPath) < 0)

-        goto cleanup;

-

-    if (qemuDomainSetupAllHostdevs(cfg, vm, devPath) < 0)

-        goto cleanup;

-

-    if (qemuDomainSetupAllMemories(cfg, vm, devPath) < 0)

-        goto cleanup;

-

-    if (qemuDomainSetupAllChardevs(cfg, vm, devPath) < 0)

-        goto cleanup;

-

-    if (qemuDomainSetupTPM(cfg, vm, devPath) < 0)

-        goto cleanup;

-

-    if (qemuDomainSetupAllGraphics(cfg, vm, devPath) < 0)

-        goto cleanup;

-

-    if (qemuDomainSetupAllInputs(cfg, vm, devPath) < 0)

-        goto cleanup;

-

-    if (qemuDomainSetupAllRNGs(cfg, vm, devPath) < 0)

-        goto cleanup;

-

     if (virFileMoveMount(devPath, "/dev") < 0)

         goto cleanup;

-- 

2.13.0