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virtiofsd: Start reading commands from queue 

Pop queue elements off queues, copy the data from them and
pass that to fuse.

  Note: 'out' in a VuVirtqElement is from QEMU
        'in' in libfuse is into the daemon

  So we read from the out iov's to get a fuse_in_header

When we get a kick we've got to read all the elements until the queue
is empty.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Dr. David Alan Gilbert 2018-06-14 19:52:23 +01:00
parent 5dcd1f5614
commit b509e1228b
2 changed files with 98 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
tools/virtiofsd/fuse_i.h
View File

@ -14,6 +14,7 @@
#include "fuse_lowlevel.h"
struct fv_VuDev;
struct fv_QueueInfo;
struct fuse_req {
struct fuse_session *se;
@ -75,6 +76,7 @@ struct fuse_chan {
pthread_mutex_t lock;
int ctr;
int fd;
struct fv_QueueInfo *qi;
};
/**

99
tools/virtiofsd/fuse_virtio.c
View File

@ -12,6 +12,7 @@
*/
#include "qemu/osdep.h"
#include "qemu/iov.h"
#include "fuse_virtio.h"
#include "fuse_i.h"
#include "standard-headers/linux/fuse.h"
@ -32,6 +33,7 @@
#include "contrib/libvhost-user/libvhost-user.h"
struct fv_VuDev;
struct fv_QueueInfo {
pthread_t thread;
struct fv_VuDev *virtio_dev;
@ -101,10 +103,41 @@ static void fv_panic(VuDev *dev, const char *err)
exit(EXIT_FAILURE);
}
/*
* Copy from an iovec into a fuse_buf (memory only)
* Caller must ensure there is space
*/
static void copy_from_iov(struct fuse_buf *buf, size_t out_num,
const struct iovec *out_sg)
{
void *dest = buf->mem;
while (out_num) {
size_t onelen = out_sg->iov_len;
memcpy(dest, out_sg->iov_base, onelen);
dest += onelen;
out_sg++;
out_num--;
}
}
/* Thread function for individual queues, created when a queue is 'started' */
static void *fv_queue_thread(void *opaque)
{
struct fv_QueueInfo *qi = opaque;
struct VuDev *dev = &qi->virtio_dev->dev;
struct VuVirtq *q = vu_get_queue(dev, qi->qidx);
struct fuse_session *se = qi->virtio_dev->se;
struct fuse_chan ch;
struct fuse_buf fbuf;
fbuf.mem = NULL;
fbuf.flags = 0;
fuse_mutex_init(&ch.lock);
ch.fd = (int)0xdaff0d111;
ch.qi = qi;
fuse_log(FUSE_LOG_INFO, "%s: Start for queue %d kick_fd %d\n", __func__,
qi->qidx, qi->kick_fd);
while (1) {
@ -141,11 +174,71 @@ static void *fv_queue_thread(void *opaque)
fuse_log(FUSE_LOG_ERR, "Eventfd_read for queue: %m\n");
break;
}
if (qi->virtio_dev->se->debug) {
fprintf(stderr, "%s: Queue %d gave evalue: %zx\n", __func__,
qi->qidx, (size_t)evalue);
/* out is from guest, in is too guest */
unsigned int in_bytes, out_bytes;
vu_queue_get_avail_bytes(dev, q, &in_bytes, &out_bytes, ~0, ~0);
fuse_log(FUSE_LOG_DEBUG,
"%s: Queue %d gave evalue: %zx available: in: %u out: %u\n",
__func__, qi->qidx, (size_t)evalue, in_bytes, out_bytes);
while (1) {
/*
* An element contains one request and the space to send our
* response They're spread over multiple descriptors in a
* scatter/gather set and we can't trust the guest to keep them
* still; so copy in/out.
*/
VuVirtqElement *elem = vu_queue_pop(dev, q, sizeof(VuVirtqElement));
if (!elem) {
break;
}
if (!fbuf.mem) {
fbuf.mem = malloc(se->bufsize);
assert(fbuf.mem);
assert(se->bufsize > sizeof(struct fuse_in_header));
}
/* The 'out' part of the elem is from qemu */
unsigned int out_num = elem->out_num;
struct iovec *out_sg = elem->out_sg;
size_t out_len = iov_size(out_sg, out_num);
fuse_log(FUSE_LOG_DEBUG,
"%s: elem %d: with %d out desc of length %zd\n", __func__,
elem->index, out_num, out_len);
/*
* The elem should contain a 'fuse_in_header' (in to fuse)
* plus the data based on the len in the header.
*/
if (out_len < sizeof(struct fuse_in_header)) {
fuse_log(FUSE_LOG_ERR, "%s: elem %d too short for in_header\n",
__func__, elem->index);
assert(0); /* TODO */
}
if (out_len > se->bufsize) {
fuse_log(FUSE_LOG_ERR, "%s: elem %d too large for buffer\n",
__func__, elem->index);
assert(0); /* TODO */
}
copy_from_iov(&fbuf, out_num, out_sg);
fbuf.size = out_len;
/* TODO! Endianness of header */
/* TODO: Fixup fuse_send_msg */
/* TODO: Add checks for fuse_session_exited */
fuse_session_process_buf_int(se, &fbuf, &ch);
/* TODO: vu_queue_push(dev, q, elem, qi->write_count); */
vu_queue_notify(dev, q);
free(elem);
elem = NULL;
}
}
pthread_mutex_destroy(&ch.lock);
free(fbuf.mem);
return NULL;
}