Block-layer backend interface for bhyve block-io device emulations.
Approved by: re@ (blanket)
This commit is contained in:
Peter Grehan
parent
89898f63c2
commit
7cf5a7eeb0
426
usr.sbin/bhyve/block_if.c
Normal file
426
usr.sbin/bhyve/block_if.c
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@ -0,0 +1,426 @@
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/*-
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* Copyright (c) 2013 Peter Grehan <grehan@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/queue.h>
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#include <sys/errno.h>
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#include <sys/stat.h>
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#include <sys/ioctl.h>
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#include <sys/disk.h>
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#include <assert.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <pthread.h>
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#include <pthread_np.h>
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#include <unistd.h>
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#include "bhyverun.h"
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#include "block_if.h"
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#define BLOCKIF_SIG 0xb109b109
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#define BLOCKIF_MAXREQ 16
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enum blockop {
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BOP_READ,
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BOP_WRITE,
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BOP_FLUSH,
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BOP_CANCEL
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};
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enum blockstat {
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BST_FREE,
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BST_INUSE
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};
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struct blockif_elem {
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TAILQ_ENTRY(blockif_elem) be_link;
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struct blockif_req *be_req;
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enum blockop be_op;
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enum blockstat be_status;
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};
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struct blockif_ctxt {
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int bc_magic;
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int bc_fd;
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int bc_rdonly;
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off_t bc_size;
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int bc_sectsz;
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pthread_t bc_btid;
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pthread_mutex_t bc_mtx;
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pthread_cond_t bc_cond;
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int bc_closing;
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/* Request elements and free/inuse queues */
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TAILQ_HEAD(, blockif_elem) bc_freeq;
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TAILQ_HEAD(, blockif_elem) bc_inuseq;
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u_int bc_req_count;
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struct blockif_elem bc_reqs[BLOCKIF_MAXREQ];
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};
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static int
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blockif_enqueue(struct blockif_ctxt *bc, struct blockif_req *breq,
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enum blockop op)
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{
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struct blockif_elem *be;
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assert(bc->bc_req_count < BLOCKIF_MAXREQ);
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be = TAILQ_FIRST(&bc->bc_freeq);
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assert(be != NULL);
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assert(be->be_status == BST_FREE);
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TAILQ_REMOVE(&bc->bc_freeq, be, be_link);
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be->be_status = BST_INUSE;
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be->be_req = breq;
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be->be_op = op;
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TAILQ_INSERT_TAIL(&bc->bc_inuseq, be, be_link);
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bc->bc_req_count++;
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return (0);
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}
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static int
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blockif_dequeue(struct blockif_ctxt *bc, struct blockif_elem *el)
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{
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struct blockif_elem *be;
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if (bc->bc_req_count == 0)
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return (ENOENT);
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be = TAILQ_FIRST(&bc->bc_inuseq);
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assert(be != NULL);
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assert(be->be_status == BST_INUSE);
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*el = *be;
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TAILQ_REMOVE(&bc->bc_inuseq, be, be_link);
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be->be_status = BST_FREE;
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be->be_req = NULL;
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TAILQ_INSERT_TAIL(&bc->bc_freeq, be, be_link);
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bc->bc_req_count--;
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return (0);
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}
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static void
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blockif_proc(struct blockif_ctxt *bc, struct blockif_elem *be)
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{
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struct blockif_req *br;
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int err;
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br = be->be_req;
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err = 0;
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switch (be->be_op) {
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case BOP_READ:
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if (preadv(bc->bc_fd, br->br_iov, br->br_iovcnt,
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br->br_offset) < 0)
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err = errno;
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break;
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case BOP_WRITE:
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if (bc->bc_rdonly)
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err = EROFS;
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else if (pwritev(bc->bc_fd, br->br_iov, br->br_iovcnt,
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br->br_offset) < 0)
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err = errno;
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break;
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case BOP_FLUSH:
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break;
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case BOP_CANCEL:
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err = EINTR;
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break;
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default:
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err = EINVAL;
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break;
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}
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(*br->br_callback)(br, err);
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}
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static void *
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blockif_thr(void *arg)
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{
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struct blockif_ctxt *bc;
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struct blockif_elem req;
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bc = arg;
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for (;;) {
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pthread_mutex_lock(&bc->bc_mtx);
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while (!blockif_dequeue(bc, &req)) {
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pthread_mutex_unlock(&bc->bc_mtx);
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blockif_proc(bc, &req);
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pthread_mutex_lock(&bc->bc_mtx);
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}
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pthread_cond_wait(&bc->bc_cond, &bc->bc_mtx);
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pthread_mutex_unlock(&bc->bc_mtx);
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/*
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* Check ctxt status here to see if exit requested
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*/
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if (bc->bc_closing)
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pthread_exit(NULL);
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}
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/* Not reached */
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return (NULL);
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}
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struct blockif_ctxt *
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blockif_open(const char *optstr, const char *ident)
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{
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char tname[MAXCOMLEN + 1];
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char *nopt, *xopts;
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struct blockif_ctxt *bc;
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struct stat sbuf;
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off_t size;
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int extra, fd, i, sectsz;
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int nocache, sync, ro;
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nocache = 0;
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sync = 0;
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ro = 0;
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/*
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* The first element in the optstring is always a pathname.
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* Optional elements follow
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*/
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nopt = strdup(optstr);
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for (xopts = strtok(nopt, ",");
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xopts != NULL;
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xopts = strtok(NULL, ",")) {
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if (!strcmp(xopts, "nocache"))
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nocache = 1;
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else if (!strcmp(xopts, "sync"))
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sync = 1;
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else if (!strcmp(xopts, "ro"))
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ro = 1;
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}
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extra = 0;
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if (nocache)
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extra |= O_DIRECT;
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if (sync)
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extra |= O_SYNC;
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fd = open(nopt, (ro ? O_RDONLY : O_RDWR) | extra);
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if (fd < 0 && !ro) {
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/* Attempt a r/w fail with a r/o open */
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fd = open(nopt, O_RDONLY | extra);
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ro = 1;
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}
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if (fd < 0) {
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perror("Could not open backing file");
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return (NULL);
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}
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if (fstat(fd, &sbuf) < 0) {
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perror("Could not stat backing file");
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close(fd);
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return (NULL);
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}
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/*
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* Deal with raw devices
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*/
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size = sbuf.st_size;
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sectsz = DEV_BSIZE;
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if (S_ISCHR(sbuf.st_mode)) {
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if (ioctl(fd, DIOCGMEDIASIZE, &size) < 0 ||
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ioctl(fd, DIOCGSECTORSIZE, §sz)) {
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perror("Could not fetch dev blk/sector size");
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close(fd);
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return (NULL);
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}
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assert(size != 0);
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assert(sectsz != 0);
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}
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bc = malloc(sizeof(struct blockif_ctxt));
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if (bc == NULL) {
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close(fd);
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return (NULL);
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}
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memset(bc, 0, sizeof(*bc));
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bc->bc_magic = BLOCKIF_SIG;
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bc->bc_fd = fd;
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bc->bc_size = size;
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bc->bc_sectsz = sectsz;
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pthread_mutex_init(&bc->bc_mtx, NULL);
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pthread_cond_init(&bc->bc_cond, NULL);
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TAILQ_INIT(&bc->bc_freeq);
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TAILQ_INIT(&bc->bc_inuseq);
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bc->bc_req_count = 0;
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for (i = 0; i < BLOCKIF_MAXREQ; i++) {
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bc->bc_reqs[i].be_status = BST_FREE;
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TAILQ_INSERT_HEAD(&bc->bc_freeq, &bc->bc_reqs[i], be_link);
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}
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pthread_create(&bc->bc_btid, NULL, blockif_thr, bc);
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snprintf(tname, sizeof(tname), "%s blk-%s", vmname, ident);
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pthread_set_name_np(bc->bc_btid, tname);
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return (bc);
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}
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static int
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blockif_request(struct blockif_ctxt *bc, struct blockif_req *breq,
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enum blockop op)
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{
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int err;
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err = 0;
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pthread_mutex_lock(&bc->bc_mtx);
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if (bc->bc_req_count < BLOCKIF_MAXREQ) {
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/*
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* Enqueue and inform the block i/o thread
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* that there is work available
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*/
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blockif_enqueue(bc, breq, op);
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pthread_cond_signal(&bc->bc_cond);
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} else {
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/*
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* Callers are not allowed to enqueue more than
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* the specified blockif queue limit. Return an
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* error to indicate that the queue length has been
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* exceeded.
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*/
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err = E2BIG;
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}
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pthread_mutex_unlock(&bc->bc_mtx);
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return (err);
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}
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int
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blockif_read(struct blockif_ctxt *bc, struct blockif_req *breq)
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{
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assert(bc->bc_magic == BLOCKIF_SIG);
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return (blockif_request(bc, breq, BOP_READ));
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}
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int
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blockif_write(struct blockif_ctxt *bc, struct blockif_req *breq)
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{
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assert(bc->bc_magic == BLOCKIF_SIG);
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return (blockif_request(bc, breq, BOP_WRITE));
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}
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int
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blockif_flush(struct blockif_ctxt *bc, struct blockif_req *breq)
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{
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assert(bc->bc_magic == BLOCKIF_SIG);
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return (blockif_request(bc, breq, BOP_FLUSH));
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}
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int
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blockif_cancel(struct blockif_ctxt *bc, struct blockif_req *breq)
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{
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assert(bc->bc_magic == BLOCKIF_SIG);
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return (blockif_request(bc, breq, BOP_CANCEL));
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}
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int
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blockif_close(struct blockif_ctxt *bc)
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{
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void *jval;
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int err;
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err = 0;
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assert(bc->bc_magic == BLOCKIF_SIG);
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/*
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* Stop the block i/o thread
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*/
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bc->bc_closing = 1;
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pthread_cond_signal(&bc->bc_cond);
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pthread_join(bc->bc_btid, &jval);
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/* XXX Cancel queued i/o's ??? */
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/*
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* Release resources
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*/
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bc->bc_magic = 0;
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close(bc->bc_fd);
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free(bc);
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return (0);
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}
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/*
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* Accessors
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*/
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off_t
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blockif_size(struct blockif_ctxt *bc)
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{
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assert(bc->bc_magic == BLOCKIF_SIG);
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return (bc->bc_size);
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}
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int
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blockif_sectsz(struct blockif_ctxt *bc)
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{
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assert(bc->bc_magic == BLOCKIF_SIG);
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return (bc->bc_sectsz);
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}
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int
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blockif_queuesz(struct blockif_ctxt *bc)
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{
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assert(bc->bc_magic == BLOCKIF_SIG);
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return (BLOCKIF_MAXREQ);
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}
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int
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blockif_is_ro(struct blockif_ctxt *bc)
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{
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assert(bc->bc_magic == BLOCKIF_SIG);
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return (bc->bc_rdonly);
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}
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64
usr.sbin/bhyve/block_if.h
Normal file
64
usr.sbin/bhyve/block_if.h
Normal file
@ -0,0 +1,64 @@
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/*-
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* Copyright (c) 2013 Peter Grehan <grehan@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in the
|
||||
* documentation and/or other materials provided with the distribution.
|
||||
*
|
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
|
||||
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||||
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||||
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
||||
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||||
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||||
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||||
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
||||
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
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* SUCH DAMAGE.
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||||
*
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* $FreeBSD$
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*/
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/*
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* The block API to be used by bhyve block-device emulations. The routines
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* are thread safe, with no assumptions about the context of the completion
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* callback - it may occur in the caller's context, or asynchronously in
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* another thread.
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*/
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#ifndef _BLOCK_IF_H_
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#define _BLOCK_IF_H_
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#include <sys/uio.h>
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#include <sys/unistd.h>
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#define BLOCKIF_IOV_MAX 32 /* not practical to be IOV_MAX */
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struct blockif_req {
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struct iovec br_iov[BLOCKIF_IOV_MAX];
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int br_iovcnt;
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off_t br_offset;
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void (*br_callback)(struct blockif_req *req, int err);
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void *br_param;
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};
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struct blockif_ctxt;
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struct blockif_ctxt *blockif_open(const char *optstr, const char *ident);
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off_t blockif_size(struct blockif_ctxt *bc);
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int blockif_sectsz(struct blockif_ctxt *bc);
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int blockif_queuesz(struct blockif_ctxt *bc);
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int blockif_is_ro(struct blockif_ctxt *bc);
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int blockif_read(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_write(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_flush(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_cancel(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_close(struct blockif_ctxt *bc);
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#endif /* _BLOCK_IF_H_ */
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