* Vivek Goyal (vgo...@redhat.com) wrote:
> As of now we don't support fcntl(F_SETLKW) and if we see one, we return
> -EOPNOTSUPP.
>
> Change that by accepting these requests and returning a reply immediately
> asking caller to wait. Once lock is available, send a notification to
> the waiter indicating lock is available.
>
> Signed-off-by: Vivek Goyal <vgo...@redhat.com>
> ---
> contrib/virtiofsd/fuse_kernel.h | 7 +++
> contrib/virtiofsd/fuse_lowlevel.c | 23 +++++++-
> contrib/virtiofsd/fuse_lowlevel.h | 25 ++++++++
> contrib/virtiofsd/fuse_virtio.c | 94 ++++++++++++++++++++++++++++--
> contrib/virtiofsd/passthrough_ll.c | 49 +++++++++++++---
> 5 files changed, 182 insertions(+), 16 deletions(-)
>
> diff --git a/contrib/virtiofsd/fuse_kernel.h b/contrib/virtiofsd/fuse_kernel.h
> index 2bdc8b1c88..d4d65c5414 100644
> --- a/contrib/virtiofsd/fuse_kernel.h
> +++ b/contrib/virtiofsd/fuse_kernel.h
> @@ -444,6 +444,7 @@ enum fuse_notify_code {
> FUSE_NOTIFY_STORE = 4,
> FUSE_NOTIFY_RETRIEVE = 5,
> FUSE_NOTIFY_DELETE = 6,
> + FUSE_NOTIFY_LOCK = 7,
> FUSE_NOTIFY_CODE_MAX,
> };
>
> @@ -836,6 +837,12 @@ struct fuse_notify_retrieve_in {
> uint64_t dummy4;
> };
>
> +struct fuse_notify_lock_out {
> + uint64_t id;
> + int32_t error;
> + int32_t padding;
> +};
> +
> /* Device ioctls: */
> #define FUSE_DEV_IOC_CLONE _IOR(229, 0, uint32_t)
>
> diff --git a/contrib/virtiofsd/fuse_lowlevel.c
> b/contrib/virtiofsd/fuse_lowlevel.c
> index d4a42d9804..f706e440bf 100644
> --- a/contrib/virtiofsd/fuse_lowlevel.c
> +++ b/contrib/virtiofsd/fuse_lowlevel.c
> @@ -183,7 +183,8 @@ int fuse_send_reply_iov_nofree(fuse_req_t req, int error,
> struct iovec *iov,
> {
> struct fuse_out_header out;
>
> - if (error <= -1000 || error > 0) {
> + /* error = 1 has been used to signal client to wait for notificaiton */
> + if (error <= -1000 || error > 1) {
> fuse_log(FUSE_LOG_ERR, "fuse: bad error value: %i\n", error);
> error = -ERANGE;
> }
> @@ -291,6 +292,12 @@ int fuse_reply_err(fuse_req_t req, int err)
> return send_reply(req, -err, NULL, 0);
> }
>
> +int fuse_reply_wait(fuse_req_t req)
> +{
> + /* TODO: This is a hack. Fix it */
> + return send_reply(req, 1, NULL, 0);
> +}
> +
> void fuse_reply_none(fuse_req_t req)
> {
> fuse_free_req(req);
> @@ -2207,6 +2214,20 @@ static int send_notify_iov(struct fuse_session *se,
> int notify_code,
> return fuse_send_msg(se, NULL, iov, count);
> }
>
> +int fuse_lowlevel_notify_lock(struct fuse_session *se, uint64_t req_id,
> + int32_t error)
> +{
> + struct fuse_notify_lock_out outarg;
> + struct iovec iov[2];
> +
> + outarg.id = req_id;
> + outarg.error = -error;
> +
> + iov[1].iov_base = &outarg;
> + iov[1].iov_len = sizeof(outarg);
> + return send_notify_iov(se, FUSE_NOTIFY_LOCK, iov, 2);
> +}
> +
> int fuse_lowlevel_notify_poll(struct fuse_pollhandle *ph)
> {
> if (ph != NULL) {
> diff --git a/contrib/virtiofsd/fuse_lowlevel.h
> b/contrib/virtiofsd/fuse_lowlevel.h
> index e664d2d12d..f0a94683b5 100644
> --- a/contrib/virtiofsd/fuse_lowlevel.h
> +++ b/contrib/virtiofsd/fuse_lowlevel.h
> @@ -1251,6 +1251,22 @@ struct fuse_lowlevel_ops {
> */
> int fuse_reply_err(fuse_req_t req, int err);
>
> +/**
> + * Ask caller to wait for lock.
> + *
> + * Possible requests:
> + * setlkw
> + *
> + * If caller sends a blocking lock request (setlkw), then reply to caller
> + * that wait for lock to be available. Once lock is available caller will
> + * receive a notification with request's unique id. Notification will
> + * carry info whether lock was successfully obtained or not.
> + *
> + * @param req request handle
> + * @return zero for success, -errno for failure to send reply
> + */
> +int fuse_reply_wait(fuse_req_t req);
> +
> /**
> * Don't send reply
> *
> @@ -1704,6 +1720,15 @@ int fuse_lowlevel_notify_delete(struct fuse_session
> *se,
> int fuse_lowlevel_notify_store(struct fuse_session *se, fuse_ino_t ino,
> off_t offset, struct fuse_bufvec *bufv,
> enum fuse_buf_copy_flags flags);
> +/**
> + * Notify event related to previous lock request
> + *
> + * @param se the session object
> + * @param req_id the id of the request which requested setlkw
> + * @param error zero for success, -errno for the failure
> + */
> +int fuse_lowlevel_notify_lock(struct fuse_session *se, uint64_t req_id,
> + int32_t error);
>
> /* ----------------------------------------------------------- *
> * Utility functions *
> diff --git a/contrib/virtiofsd/fuse_virtio.c b/contrib/virtiofsd/fuse_virtio.c
> index 982b6ad0bd..98d27e7642 100644
> --- a/contrib/virtiofsd/fuse_virtio.c
> +++ b/contrib/virtiofsd/fuse_virtio.c
> @@ -215,6 +215,81 @@ static void copy_iov(struct iovec *src_iov, int
> src_count,
> }
> }
>
> +static int virtio_send_notify_msg(struct fuse_session *se, struct iovec *iov,
> + int count)
> +{
> + struct fv_QueueInfo *qi;
> + VuDev *dev = &se->virtio_dev->dev;
> + VuVirtq *q;
> + FVRequest *req;
> + VuVirtqElement *elem;
> + unsigned int in_num, bad_in_num = 0, bad_out_num = 0;
> + struct fuse_out_header *out = iov[0].iov_base;
> + size_t in_len, tosend_len = iov_size(iov, count);
> + struct iovec *in_sg;
> + int ret = 0;
> +
> + /* Notifications have unique == 0 */
> + assert (!out->unique);
> +
> + if (!se->notify_enabled)
> + return -EOPNOTSUPP;
> +
> + /* If notifications are enabled, queue index 1 is notification queue */
> + qi = se->virtio_dev->qi[1];
> + q = vu_get_queue(dev, qi->qidx);
> +
> + pthread_rwlock_rdlock(&qi->virtio_dev->vu_dispatch_rwlock);
> + pthread_mutex_lock(&qi->vq_lock);
> + /* Pop an element from queue */
> + req = vu_queue_pop(dev, q, sizeof(FVRequest), &bad_in_num, &bad_out_num);
You don't need bad_in_num/bad_out_num - just pass NULL for both; they're
only needed if you expect to read/write data that's not mappable (i.e.
in our direct write case).
> + if (!req) {
> + /* TODO: Implement some sort of ring buffer and queue notifications
> + * on that and send these later when notification queue has space
> + * available.
> + */
> + return -ENOSPC;
> + }
> + pthread_mutex_unlock(&qi->vq_lock);
> + pthread_rwlock_unlock(&qi->virtio_dev->vu_dispatch_rwlock);
> +
> + out->len = tosend_len;
> + elem = &req->elem;
> + in_num = elem->in_num;
> + in_sg = elem->in_sg;
> + in_len = iov_size(in_sg, in_num);
> + fuse_log(FUSE_LOG_DEBUG, "%s: elem %d: with %d in desc of length %zd\n",
> + __func__, elem->index, in_num, in_len);
> +
> + if (in_len < sizeof(struct fuse_out_header)) {
> + fuse_log(FUSE_LOG_ERR, "%s: elem %d too short for out_header\n",
> + __func__, elem->index);
> + ret = -E2BIG;
> + goto out;
> + }
> +
> + if (in_len < tosend_len) {
> + fuse_log(FUSE_LOG_ERR, "%s: elem %d too small for data len"
> + " %zd\n", __func__, elem->index, tosend_len);
> + ret = -E2BIG;
> + goto out;
> + }
> +
> + /* First copy the header data from iov->in_sg */
> + copy_iov(iov, count, in_sg, in_num, tosend_len);
> +
> + /* TODO: Add bad_innum handling */
> + pthread_rwlock_rdlock(&qi->virtio_dev->vu_dispatch_rwlock);
> + pthread_mutex_lock(&qi->vq_lock);
> + vu_queue_push(dev, q, elem, tosend_len);
> + vu_queue_notify(dev, q);
> + pthread_mutex_unlock(&qi->vq_lock);
> + pthread_rwlock_unlock(&qi->virtio_dev->vu_dispatch_rwlock);
> +out:
> + free(req);
> + return ret;
> +}
> +
> /*
> * Called back by ll whenever it wants to send a reply/message back
> * The 1st element of the iov starts with the fuse_out_header
> @@ -223,11 +298,11 @@ static void copy_iov(struct iovec *src_iov, int
> src_count,
> int virtio_send_msg(struct fuse_session *se, struct fuse_chan *ch,
> struct iovec *iov, int count)
> {
> - FVRequest *req = container_of(ch, FVRequest, ch);
> - struct fv_QueueInfo *qi = ch->qi;
> + FVRequest *req;
> + struct fv_QueueInfo *qi;
> VuDev *dev = &se->virtio_dev->dev;
> - VuVirtq *q = vu_get_queue(dev, qi->qidx);
> - VuVirtqElement *elem = &req->elem;
> + VuVirtq *q;
> + VuVirtqElement *elem;
> int ret = 0;
>
> assert(count >= 1);
> @@ -238,8 +313,15 @@ int virtio_send_msg(struct fuse_session *se, struct
> fuse_chan *ch,
>
> size_t tosend_len = iov_size(iov, count);
>
> - /* unique == 0 is notification, which we don't support */
> - assert(out->unique);
> + /* unique == 0 is notification */
> + if (!out->unique)
> + return virtio_send_notify_msg(se, iov, count);
> +
> + assert(ch);
> + req = container_of(ch, FVRequest, ch);
> + elem = &req->elem;
> + qi = ch->qi;
> + q = vu_get_queue(dev, qi->qidx);
> assert(!req->reply_sent);
>
> /* The 'in' part of the elem is to qemu */
> diff --git a/contrib/virtiofsd/passthrough_ll.c
> b/contrib/virtiofsd/passthrough_ll.c
> index 028e7da273..ed52953565 100644
> --- a/contrib/virtiofsd/passthrough_ll.c
> +++ b/contrib/virtiofsd/passthrough_ll.c
> @@ -1925,7 +1925,10 @@ static void lo_setlk(fuse_req_t req, fuse_ino_t ino,
> struct lo_data *lo = lo_data(req);
> struct lo_inode *inode;
> struct lo_inode_plock *plock;
> - int ret, saverr = 0;
> + int ret, saverr = 0, ofd;
> + uint64_t unique;
> + struct fuse_session *se = req->se;
> + bool async_lock = false;
>
> fuse_log(FUSE_LOG_DEBUG, "lo_setlk(ino=%" PRIu64 ", flags=%d)"
> " cmd=%d pid=%d owner=0x%lx sleep=%d l_whence=%d"
> @@ -1933,11 +1936,6 @@ static void lo_setlk(fuse_req_t req, fuse_ino_t ino,
> lock->l_type, lock->l_pid, fi->lock_owner, sleep,
> lock->l_whence, lock->l_start, lock->l_len);
>
> - if (sleep) {
> - fuse_reply_err(req, EOPNOTSUPP);
> - return;
> - }
> -
> inode = lo_inode(req, ino);
> if (!inode) {
> fuse_reply_err(req, EBADF);
> @@ -1950,21 +1948,54 @@ static void lo_setlk(fuse_req_t req, fuse_ino_t ino,
>
> if (!plock) {
> saverr = ret;
> + pthread_mutex_unlock(&inode->plock_mutex);
> goto out;
> }
>
> + /*
> + * plock is now released when inode is going away. We already have
> + * a reference on inode, so it is guaranteed that plock->fd is
> + * still around even after dropping inode->plock_mutex lock
> + */
> + ofd = plock->fd;
> + pthread_mutex_unlock(&inode->plock_mutex);
> +
> + /*
> + * If this lock request can block, request caller to wait for
> + * notification. Do not access req after this. Once lock is
> + * available, send a notification instead.
> + */
> + if (sleep && lock->l_type != F_UNLCK) {
> + /*
> + * If notification queue is not enabled, can't support async
> + * locks.
> + */
> + if (!se->notify_enabled) {
> + saverr = EOPNOTSUPP;
> + goto out;
> + }
> + async_lock = true;
> + unique = req->unique;
> + fuse_reply_wait(req);
> + }
> /* TODO: Is it alright to modify flock? */
> lock->l_pid = 0;
> - ret = fcntl(plock->fd, F_OFD_SETLK, lock);
> + if (async_lock)
> + ret = fcntl(ofd, F_OFD_SETLKW, lock);
> + else
> + ret = fcntl(ofd, F_OFD_SETLK, lock);
What happens if the guest is rebooted after it's asked
for, but not been granted a lock?
Dave
> if (ret == -1) {
> saverr = errno;
> }
>
> out:
> - pthread_mutex_unlock(&inode->plock_mutex);
> lo_inode_put(lo, &inode);
>
> - fuse_reply_err(req, saverr);
> + if (!async_lock)
> + fuse_reply_err(req, saverr);
> + else {
> + fuse_lowlevel_notify_lock(se, unique, saverr);
> + }
> }
>
> static void lo_fsyncdir(fuse_req_t req, fuse_ino_t ino, int datasync,
> --
> 2.20.1
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
