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

On Tue, Nov 10, 2020 at 10:10:16AM -0300, Daniel Henrique Barboza wrote: > > > On 11/10/20 2:04 AM, Masayoshi Mizuma wrote: > > From: Masayoshi Mizuma <m.mizuma(a)jp.fujitsu.com&gt; > > > > 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 > > > s/staring/start ? > > > > and virtlogd keeps to opening the log file. > > > > Stop virtiofsd when the qemu guest fails to start. > > > > Signed-off-by: Masayoshi Mizuma <m.mizuma(a)jp.fujitsu.com&gt; > > --- > > 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); > > + > > > If you're adamant into killing 'pid' I suggest to just verify "if (pid)" and > then execute virProcessKillPainfully(), like is being done in virPidFileForceCleanupPath() > that is called right before. > > Speaking of which, isn't virPidFileForceCleanupPath() responsible of killing > virtiofsd? If that's the case, the function is failing to do so in the scenario > you described, but it will succeed in all other cases. The result is that you'll > end up trying to kill the process twice. > > Making a guess about what might be happening, if 'pidfile' does not exist in your error > scenario then virPidFileForceCleanupPath() is returning 0 but is doing nothing. This is > the case where your code might come in and kill the pid manually. Thank you pointing it out! Your guess is correct. The pid file was removed by virFileDeleteTree(priv->libDir) in qemuProcessStop(), so virtiofsd isn't killed by virPidFileForceCleanupPath().