[PATCH] qemu: virtiofs: Stop virtiofsd when the qemu guest fails to start

[Masayoshi Mizuma <msys.mizuma@xxxxxxxxx>]

From: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>

A qemu guest which has virtiofs config fails to start if the previous
starting failed because of invalid option or something.
For example of the reproduction:

  # virsh start guest
  error: Failed to start domain guest
  error: internal error: process exited while connecting to monitor: qemu-system-x86_64: -foo: invalid option

  ... fix the option ...

  # virsh start guest
  error: Failed to start domain guest
  error: Cannot open log file: '/var/log/libvirt/qemu/guest-fs0-virtiofsd.log': Device or resource busy
  # 

That's because the virtiofsd which was executed on the former staring remains
and virtlogd keeps to opening the log file.

Stop virtiofsd when the qemu guest fails to start.

Signed-off-by: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
---
 src/qemu/qemu_domain.h   | 1 +
 src/qemu/qemu_virtiofs.c | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index ca041e207b..7d47c030bd 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -426,6 +426,7 @@ struct _qemuDomainFSPrivate {
     virObject parent;
 
     char *vhostuser_fs_sock;
+    pid_t virtiofsd_pid;
 };
 
 
diff --git a/src/qemu/qemu_virtiofs.c b/src/qemu/qemu_virtiofs.c
index 2e239cad66..8684219915 100644
--- a/src/qemu/qemu_virtiofs.c
+++ b/src/qemu/qemu_virtiofs.c
@@ -250,6 +250,7 @@ qemuVirtioFSStart(virLogManagerPtr logManager,
     }
 
     QEMU_DOMAIN_FS_PRIVATE(fs)->vhostuser_fs_sock = g_steal_pointer(&socket_path);
+    QEMU_DOMAIN_FS_PRIVATE(fs)->virtiofsd_pid = pid;
     ret = 0;
 
  cleanup:
@@ -273,6 +274,7 @@ qemuVirtioFSStop(virQEMUDriverPtr driver G_GNUC_UNUSED,
 {
     g_autofree char *pidfile = NULL;
     virErrorPtr orig_err;
+    pid_t pid = QEMU_DOMAIN_FS_PRIVATE(fs)->virtiofsd_pid;
 
     virErrorPreserveLast(&orig_err);
 
@@ -286,6 +288,9 @@ qemuVirtioFSStop(virQEMUDriverPtr driver G_GNUC_UNUSED,
             unlink(QEMU_DOMAIN_FS_PRIVATE(fs)->vhostuser_fs_sock);
     }
 
+    if (virProcessKill(pid, 0) == 0)
+        virProcessKillPainfully(pid, true);
+
  cleanup:
     virErrorRestore(&orig_err);
 }
-- 
2.27.0