qemu/tools/virtiofsd
Stefan Hajnoczi e7b337326d virtiofsd: prevent fv_queue_thread() vs virtio_loop() races
We call into libvhost-user from the virtqueue handler thread and the
vhost-user message processing thread without a lock.  There is nothing
protecting the virtqueue handler thread if the vhost-user message
processing thread changes the virtqueue or memory table while it is
running.

This patch introduces a read-write lock.  Virtqueue handler threads are
readers.  The vhost-user message processing thread is a writer.  This
will allow concurrency for multiqueue in the future while protecting
against fv_queue_thread() vs virtio_loop() races.

Note that the critical sections could be made smaller but it would be
more invasive and require libvhost-user changes.  Let's start simple and
improve performance later, if necessary.  Another option would be an
RCU-style approach with lighter-weight primitives.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-01-23 16:41:37 +00:00
..
50-qemu-virtiofsd.json.in virtiofsd: add vhost-user.json file 2020-01-23 16:41:36 +00:00
Makefile.objs virtiofsd: add seccomp whitelist 2020-01-23 16:41:37 +00:00
buffer.c virtiofsd: add fuse_mbuf_iter API 2020-01-23 16:41:36 +00:00
fuse.h virtiofsd: Format imported files to qemu style 2020-01-23 16:41:36 +00:00
fuse_common.h virtiofsd: Parse flag FUSE_WRITE_KILL_PRIV 2020-01-23 16:41:37 +00:00
fuse_i.h virtiofsd: Plumb fuse_bufvec through to do_write_buf 2020-01-23 16:41:36 +00:00
fuse_log.c virtiofsd: Fix common header and define for QEMU builds 2020-01-23 16:41:36 +00:00
fuse_log.h virtiofsd: Format imported files to qemu style 2020-01-23 16:41:36 +00:00
fuse_lowlevel.c virtiofsd: use fuse_lowlevel_is_virtio() in fuse_session_destroy() 2020-01-23 16:41:37 +00:00
fuse_lowlevel.h virtiofsd: print log only when priority is high enough 2020-01-23 16:41:37 +00:00
fuse_misc.h virtiofsd: support nanosecond resolution for file timestamp 2020-01-23 16:41:37 +00:00
fuse_opt.c virtiofsd: Fix common header and define for QEMU builds 2020-01-23 16:41:36 +00:00
fuse_opt.h virtiofsd: Format imported files to qemu style 2020-01-23 16:41:36 +00:00
fuse_signals.c virtiofsd: Fix common header and define for QEMU builds 2020-01-23 16:41:36 +00:00
fuse_virtio.c virtiofsd: prevent fv_queue_thread() vs virtio_loop() races 2020-01-23 16:41:37 +00:00
fuse_virtio.h virtiofsd: cleanup allocated resource in se 2020-01-23 16:41:37 +00:00
helper.c virtiofsd: Support remote posix locks 2020-01-23 16:41:37 +00:00
passthrough_helpers.h virtiofsd: Format imported files to qemu style 2020-01-23 16:41:36 +00:00
passthrough_ll.c virtiofsd: Support remote posix locks 2020-01-23 16:41:37 +00:00
seccomp.c virtiofsd: add --syslog command-line option 2020-01-23 16:41:37 +00:00
seccomp.h virtiofsd: add --syslog command-line option 2020-01-23 16:41:37 +00:00