* Daniel P. Berrangé (berrange@redhat.com) wrote:
> On Thu, Dec 12, 2019 at 04:38:19PM +0000, Dr. David Alan Gilbert (git) wrote:
> > From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
> >
> > virtiofsd has some threads, so we see a lot of logs with debug option.
> > It would be useful for debugging if we can identify the specific thread
> > from the log.
> >
> > Add ID, which is got by gettid(), to the log with FUSE_LOG_DEBUG level
> > so that we can grep the specific thread.
> >
> > The log is like as:
> >
> > ]# ./virtiofsd -d -o vhost_user_socket=/tmp/vhostqemu0 -o source=/tmp/share0 -o cache=auto
> > ...
> > [ID: 00000097] unique: 12696, success, outsize: 120
> > [ID: 00000097] virtio_send_msg: elem 18: with 2 in desc of length 120
> > [ID: 00000003] fv_queue_thread: Got queue event on Queue 1
> > [ID: 00000003] fv_queue_thread: Queue 1 gave evalue: 1 available: in: 65552 out: 80
> > [ID: 00000003] fv_queue_thread: Waiting for Queue 1 event
> > [ID: 00000071] fv_queue_worker: elem 33: with 2 out desc of length 80 bad_in_num=0 bad_out_num=0
> > [ID: 00000071] unique: 12694, opcode: READ (15), nodeid: 2, insize: 80, pid: 2014
> > [ID: 00000071] lo_read(ino=2, size=65536, off=131072)
> >
> > Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
> > ---
> > tools/virtiofsd/passthrough_ll.c | 13 ++++++++++++-
> > 1 file changed, 12 insertions(+), 1 deletion(-)
>
> >
> > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
> > index 6f398a7ff2..8e00a90e6f 100644
> > --- a/tools/virtiofsd/passthrough_ll.c
> > +++ b/tools/virtiofsd/passthrough_ll.c
> > @@ -42,6 +42,7 @@
> > #include <cap-ng.h>
> > #include <dirent.h>
> > #include <errno.h>
> > +#include <glib.h>
> > #include <inttypes.h>
> > #include <limits.h>
> > #include <pthread.h>
> > @@ -2248,12 +2249,18 @@ static void setup_nofile_rlimit(void)
> > }
> > }
> >
> > -static void log_func(enum fuse_log_level level, const char *fmt, va_list ap)
> > +static void log_func(enum fuse_log_level level, const char *_fmt, va_list ap)
> > {
> > + char *fmt = (char *)_fmt;
>
> Reusing a variable for data that may be const from stack or
> non-const from heap is really gross & asking for trouble.
Yeh, that is a bit of a hack.
> If instead it does:
>
> g_autofree *localfmt = NULL;
^ char
> > +
> > if (current_log_level < level) {
> > return;
> > }
> >
> > + if (current_log_level == FUSE_LOG_DEBUG) {
> > + fmt = g_strdup_printf("[ID: %08ld] %s", syscall(__NR_gettid), _fmt);
>
> Then:
>
> localfmt = g_strdup_printf(....)
> fmt = localfmt;
>
> > + }
> > +
> > if (use_syslog) {
> > int priority = LOG_ERR;
> > switch (level) {
> > @@ -2286,6 +2293,10 @@ static void log_func(enum fuse_log_level level, const char *fmt, va_list ap)
> > } else {
> > vfprintf(stderr, fmt, ap);
> > }
> > +
> > + if (current_log_level == FUSE_LOG_DEBUG) {
> > + g_free(fmt);
> > + }
>
> This can then be deleted.
Yes, that works nicely.
Dave
> > }
>
> Regards,
> Daniel
> --
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--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK