Hi, Here is the implementation for the remote blocking posix locks in virtiofsd.
This patch series also addresses the issues that were not fixed in: [Virtio-fs] [PATCH v2 0/5] [RFC] virtiofsd, vhost-user-fs: Add support for notification queue https://patchwork.kernel.org/project/qemu-devel/cover/20191204190836.31324-1-vgo...@redhat.com/ The main issue was that the guest could not reboot when a thread of the virtiofsd process was blocked, waiting to acquire a lock. The introduction of a custom threadpool dedicated to servicing only locking requests addresses the aforementioned issue. Description: Through the addition of a notification queue it is possible for a guest now to block waiting for a remote lock held by another guest. When the lock is available virtiofsd sends a notification to the guest that unblocks the process/thread waiting for the lock in order to acquire it. This implementation also handles cases where the guest that is waiting for a lock, hard-reboots through SYSRQ (echo "b" > /proc/sysrq-trigger). Specifically, a custom threadpool (posix theads) in virtiofsd is used to service the locking requests. If one of the threads is blocked waiting for a lock and the guest hard-reboots then virtiofsd sends a signal to the blocked thread waking it up so that it exits and then virtiofsd cleans up its state and re-initializes. Finally, the custom threadpool enables virtiofsd to concurrently service other requests that are non-blocking or block for a limited time while the custom threadpool services locking requests that might block. This is especially useful in the case where the GThreadPool is not utilized. Thanks, Ioannis Ioannis Angelakopoulos (2): virtiofsd: Thread state cleanup when blocking posix locks are used virtiofsd: Custom threadpool for remote blocking posix locks requests Vivek Goyal (4): virtiofsd: Release file locks using F_UNLCK virtiofsd: Create a notification queue virtiofsd: Specify size of notification buffer using config space virtiofsd: Implement blocking posix locks hw/virtio/vhost-user-fs.c | 57 +- include/hw/virtio/vhost-user-fs.h | 4 +- include/standard-headers/linux/fuse.h | 8 + include/standard-headers/linux/virtio_fs.h | 5 + tools/virtiofsd/fuse_i.h | 2 + tools/virtiofsd/fuse_lowlevel.c | 40 +- tools/virtiofsd/fuse_lowlevel.h | 26 + tools/virtiofsd/fuse_virtio.c | 626 +++++++++++++++++++-- tools/virtiofsd/passthrough_ll.c | 90 ++- 9 files changed, 804 insertions(+), 54 deletions(-) -- 2.27.0
