acrn-hypervisor/devicemodel/hw/block_if.c

1062 lines
22 KiB
C

/*-
* Copyright (c) 2013 Peter Grehan <grehan@freebsd.org>
* All rights reserved.
*
* 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.
*
* 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
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <linux/falloc.h>
#include <linux/fs.h>
#include <errno.h>
#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <signal.h>
#include <unistd.h>
#include "dm.h"
#include "block_if.h"
#include "ahci.h"
#include "dm_string.h"
#include "log.h"
/*
* Notes:
* The F_OFD_SETLK support is introduced in glibc 2.20.
* The glibc version on target board is above 2.20.
* The following code temporarily fixes up building issues on Ubuntu 14.04,
* where the glibc version is 2.19 by default.
* Theoretically we should use cross-compiling tool to compile applications.
*/
#ifndef F_OFD_SETLK
#define F_OFD_SETLK 37
#endif
#define BLOCKIF_SIG 0xb109b109
#define BLOCKIF_NUMTHR 8
#define BLOCKIF_MAXREQ (64 + BLOCKIF_NUMTHR)
#define MAX_DISCARD_SEGMENT 256
/*
* Debug printf
*/
static int block_if_debug;
#define DPRINTF(params) do { if (block_if_debug) pr_dbg params; } while (0)
#define WPRINTF(params) (pr_err params)
enum blockop {
BOP_READ,
BOP_WRITE,
BOP_FLUSH,
BOP_DISCARD
};
enum blockstat {
BST_FREE,
BST_BLOCK,
BST_PEND,
BST_BUSY,
BST_DONE
};
struct blockif_elem {
TAILQ_ENTRY(blockif_elem) link;
struct blockif_req *req;
enum blockop op;
enum blockstat status;
pthread_t tid;
off_t block;
};
struct blockif_ctxt {
int fd;
int isblk;
int candiscard;
int rdonly;
off_t size;
int sub_file_assign;
off_t sub_file_start_lba;
struct flock fl;
int sectsz;
int psectsz;
int psectoff;
int max_discard_sectors;
int max_discard_seg;
int discard_sector_alignment;
int closing;
pthread_t btid[BLOCKIF_NUMTHR];
pthread_mutex_t mtx;
pthread_cond_t cond;
/* Request elements and free/pending/busy queues */
TAILQ_HEAD(, blockif_elem) freeq;
TAILQ_HEAD(, blockif_elem) pendq;
TAILQ_HEAD(, blockif_elem) busyq;
struct blockif_elem reqs[BLOCKIF_MAXREQ];
/* write cache enable */
uint8_t wce;
};
static pthread_once_t blockif_once = PTHREAD_ONCE_INIT;
struct blockif_sig_elem {
pthread_mutex_t mtx;
pthread_cond_t cond;
int pending;
struct blockif_sig_elem *next;
};
struct discard_range {
uint64_t sector;
uint32_t num_sectors;
uint32_t flags;
};
static struct blockif_sig_elem *blockif_bse_head;
static int
blockif_flush_cache(struct blockif_ctxt *bc)
{
int err;
err = 0;
if (!bc->wce) {
if (fsync(bc->fd))
err = errno;
}
return err;
}
static int
blockif_enqueue(struct blockif_ctxt *bc, struct blockif_req *breq,
enum blockop op)
{
struct blockif_elem *be, *tbe;
off_t off;
int i;
be = TAILQ_FIRST(&bc->freeq);
if (be == NULL || be->status != BST_FREE) {
WPRINTF(("%s: failed to get element from freeq\n", __func__));
return 0;
}
TAILQ_REMOVE(&bc->freeq, be, link);
be->req = breq;
be->op = op;
switch (op) {
case BOP_READ:
case BOP_WRITE:
case BOP_DISCARD:
off = breq->offset;
for (i = 0; i < breq->iovcnt; i++)
off += breq->iov[i].iov_len;
break;
default:
/* off = OFF_MAX; */
off = 1 << (sizeof(off_t) - 1);
}
be->block = off;
TAILQ_FOREACH(tbe, &bc->pendq, link) {
if (tbe->block == breq->offset)
break;
}
if (tbe == NULL) {
TAILQ_FOREACH(tbe, &bc->busyq, link) {
if (tbe->block == breq->offset)
break;
}
}
if (tbe == NULL)
be->status = BST_PEND;
else
be->status = BST_BLOCK;
TAILQ_INSERT_TAIL(&bc->pendq, be, link);
return (be->status == BST_PEND);
}
static int
blockif_dequeue(struct blockif_ctxt *bc, pthread_t t, struct blockif_elem **bep)
{
struct blockif_elem *be;
TAILQ_FOREACH(be, &bc->pendq, link) {
if (be->status == BST_PEND)
break;
}
if (be == NULL)
return 0;
TAILQ_REMOVE(&bc->pendq, be, link);
be->status = BST_BUSY;
be->tid = t;
TAILQ_INSERT_TAIL(&bc->busyq, be, link);
*bep = be;
return 1;
}
static void
blockif_complete(struct blockif_ctxt *bc, struct blockif_elem *be)
{
struct blockif_elem *tbe;
if (be->status == BST_DONE || be->status == BST_BUSY)
TAILQ_REMOVE(&bc->busyq, be, link);
else
TAILQ_REMOVE(&bc->pendq, be, link);
TAILQ_FOREACH(tbe, &bc->pendq, link) {
if (tbe->req->offset == be->block)
tbe->status = BST_PEND;
}
be->tid = 0;
be->status = BST_FREE;
be->req = NULL;
TAILQ_INSERT_TAIL(&bc->freeq, be, link);
}
static int
discard_range_validate(struct blockif_ctxt *bc, off_t start, off_t size)
{
off_t start_sector = start / DEV_BSIZE;
off_t size_sector = size / DEV_BSIZE;
if (!size || (start + size) > (bc->size + bc->sub_file_start_lba))
return -1;
if ((size_sector > bc->max_discard_sectors) ||
(bc->discard_sector_alignment &&
start_sector % bc->discard_sector_alignment))
return -1;
return 0;
}
static int
blockif_process_discard(struct blockif_ctxt *bc, struct blockif_req *br)
{
int err;
struct discard_range *range;
int n_range, i, segment;
off_t arg[MAX_DISCARD_SEGMENT][2];
err = 0;
n_range = 0;
segment = 0;
if (!bc->candiscard)
return EOPNOTSUPP;
if (bc->rdonly)
return EROFS;
if (br->iovcnt == 1) {
/* virtio-blk use iov to transfer discard range */
n_range = br->iov[0].iov_len/sizeof(*range);
range = br->iov[0].iov_base;
for (i = 0; i < n_range; i++) {
arg[i][0] = range[i].sector * DEV_BSIZE +
bc->sub_file_start_lba;
arg[i][1] = range[i].num_sectors * DEV_BSIZE;
segment++;
if (segment > bc->max_discard_seg) {
WPRINTF(("segment > max_discard_seg\n"));
return EINVAL;
}
if (discard_range_validate(bc, arg[i][0], arg[i][1])) {
WPRINTF(("range [%ld: %ld] is invalid\n", arg[i][0], arg[i][1]));
return EINVAL;
}
}
} else {
/* ahci parse discard range to br->offset and br->reside */
arg[0][0] = br->offset + bc->sub_file_start_lba;
arg[0][1] = br->resid;
segment = 1;
}
for (i = 0; i < segment; i++) {
if (bc->isblk) {
err = ioctl(bc->fd, BLKDISCARD, arg[i]);
} else {
/* FALLOC_FL_PUNCH_HOLE:
* Deallocates space in the byte range starting at offset and
* continuing for length bytes. After a successful call,
* subsequent reads from this range will return zeroes.
* FALLOC_FL_KEEP_SIZE:
* Do not modify the apparent length of the file.
*/
err = fallocate(bc->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
arg[i][0], arg[i][1]);
if (!err)
err = fdatasync(bc->fd);
}
if (err) {
WPRINTF(("Failed to discard offset=%ld nbytes=%ld err code: %d\n",
arg[i][0], arg[i][1], err));
return err;
}
}
br->resid = 0;
return 0;
}
static void
blockif_proc(struct blockif_ctxt *bc, struct blockif_elem *be)
{
struct blockif_req *br;
ssize_t len;
int err;
br = be->req;
err = 0;
switch (be->op) {
case BOP_READ:
len = preadv(bc->fd, br->iov, br->iovcnt,
br->offset + bc->sub_file_start_lba);
if (len < 0)
err = errno;
else
br->resid -= len;
break;
case BOP_WRITE:
if (bc->rdonly) {
err = EROFS;
break;
}
len = pwritev(bc->fd, br->iov, br->iovcnt,
br->offset + bc->sub_file_start_lba);
if (len < 0)
err = errno;
else {
br->resid -= len;
err = blockif_flush_cache(bc);
}
break;
case BOP_FLUSH:
if (fsync(bc->fd))
err = errno;
break;
case BOP_DISCARD:
err = blockif_process_discard(bc, br);
break;
default:
err = EINVAL;
break;
}
be->status = BST_DONE;
(*br->callback)(br, err);
}
static void *
blockif_thr(void *arg)
{
struct blockif_ctxt *bc;
struct blockif_elem *be;
pthread_t t;
bc = arg;
t = pthread_self();
pthread_mutex_lock(&bc->mtx);
for (;;) {
while (blockif_dequeue(bc, t, &be)) {
pthread_mutex_unlock(&bc->mtx);
blockif_proc(bc, be);
pthread_mutex_lock(&bc->mtx);
blockif_complete(bc, be);
}
/* Check ctxt status here to see if exit requested */
if (bc->closing)
break;
pthread_cond_wait(&bc->cond, &bc->mtx);
}
pthread_mutex_unlock(&bc->mtx);
pthread_exit(NULL);
return NULL;
}
static void
blockif_sigcont_handler(int signal)
{
struct blockif_sig_elem *bse;
WPRINTF(("block_if sigcont handler!\n"));
for (;;) {
/*
* Process the entire list even if not intended for
* this thread.
*/
do {
bse = blockif_bse_head;
if (bse == NULL)
return;
} while (!__sync_bool_compare_and_swap(
(uintptr_t *)&blockif_bse_head,
(uintptr_t)bse,
(uintptr_t)bse->next));
pthread_mutex_lock(&bse->mtx);
bse->pending = 0;
pthread_cond_signal(&bse->cond);
pthread_mutex_unlock(&bse->mtx);
}
}
static void
blockif_init(void)
{
signal(SIGCONT, blockif_sigcont_handler);
}
/*
* This function checks if the sub file range, specified by sub_start and
* sub_size, has any overlap with other sub file ranges with write access.
*/
static int
sub_file_validate(struct blockif_ctxt *bc, int fd, int read_only,
off_t sub_start, off_t sub_size)
{
struct flock *fl = &bc->fl;
memset(fl, 0, sizeof(struct flock));
fl->l_whence = SEEK_SET; /* offset base is start of file */
if (read_only)
fl->l_type = F_RDLCK;
else
fl->l_type = F_WRLCK;
fl->l_start = sub_start;
fl->l_len = sub_size;
/* use "open file description locks" to validate */
if (fcntl(fd, F_OFD_SETLK, fl) == -1) {
DPRINTF(("failed to lock subfile!\n"));
return -1;
}
/* Keep file lock on to prevent other sub files, until DM exits */
return 0;
}
void
sub_file_unlock(struct blockif_ctxt *bc)
{
struct flock *fl;
if (bc->sub_file_assign) {
fl = &bc->fl;
DPRINTF(("blockif: release file lock...\n"));
fl->l_type = F_UNLCK;
if (fcntl(bc->fd, F_OFD_SETLK, fl) == -1) {
pr_err("blockif: failed to unlock subfile!\n");
exit(1);
}
DPRINTF(("blockif: release done\n"));
}
}
struct blockif_ctxt *
blockif_open(const char *optstr, const char *ident)
{
char tname[MAXCOMLEN + 1];
/* char name[MAXPATHLEN]; */
char *nopt, *xopts, *cp;
struct blockif_ctxt *bc;
struct stat sbuf;
/* struct diocgattr_arg arg; */
off_t size, psectsz, psectoff;
int fd, i, sectsz;
int writeback, ro, candiscard, ssopt, pssopt;
long sz;
long long b;
int err_code = -1;
off_t sub_file_start_lba, sub_file_size;
int sub_file_assign;
int max_discard_sectors, max_discard_seg, discard_sector_alignment;
off_t probe_arg[] = {0, 0};
pthread_once(&blockif_once, blockif_init);
fd = -1;
ssopt = 0;
pssopt = 0;
ro = 0;
sub_file_assign = 0;
sub_file_start_lba = 0;
sub_file_size = 0;
max_discard_sectors = -1;
max_discard_seg = -1;
discard_sector_alignment = -1;
/* writethru is on by default */
writeback = 0;
candiscard = 0;
/*
* The first element in the optstring is always a pathname.
* Optional elements follow
*/
nopt = xopts = strdup(optstr);
if (!nopt) {
WPRINTF(("block_if.c: strdup retruns NULL\n"));
return NULL;
}
while (xopts != NULL) {
cp = strsep(&xopts, ",");
if (cp == nopt) /* file or device pathname */
continue;
else if (!strcmp(cp, "writeback"))
writeback = 1;
else if (!strcmp(cp, "writethru"))
writeback = 0;
else if (!strcmp(cp, "ro"))
ro = 1;
else if (!strncmp(cp, "discard", strlen("discard"))) {
strsep(&cp, "=");
if (cp != NULL) {
if (!(!dm_strtoi(cp, &cp, 10, &max_discard_sectors) &&
*cp == ':' &&
!dm_strtoi(cp + 1, &cp, 10, &max_discard_seg) &&
*cp == ':' &&
!dm_strtoi(cp + 1, &cp, 10, &discard_sector_alignment)))
goto err;
}
candiscard = 1;
} else if (!strncmp(cp, "sectorsize", strlen("sectorsize"))) {
/*
* sectorsize=<sector size>
* or
* sectorsize=<sector size>/<physical sector size>
*/
if (strsep(&cp, "=") && !dm_strtoi(cp, &cp, 10, &ssopt)) {
pssopt = ssopt;
if (*cp == '/' &&
dm_strtoi(cp + 1, &cp, 10, &pssopt) < 0)
goto err;
} else {
goto err;
}
} else if (!strncmp(cp, "range", strlen("range"))) {
/* range=<start lba>/<subfile size> */
if (strsep(&cp, "=") &&
!dm_strtol(cp, &cp, 10, &sub_file_start_lba) &&
*cp == '/' &&
!dm_strtol(cp + 1, &cp, 10, &sub_file_size))
sub_file_assign = 1;
else
goto err;
} else {
pr_err("Invalid device option \"%s\"\n", cp);
goto err;
}
}
/*
* To support "writeback" and "writethru" mode switch during runtime,
* O_SYNC is not used directly, as O_SYNC flag cannot dynamic change
* after file is opened. Instead, we call fsync() after each write
* operation to emulate it.
*/
fd = open(nopt, ro ? O_RDONLY : O_RDWR);
if (fd < 0 && !ro) {
/* Attempt a r/w fail with a r/o open */
fd = open(nopt, O_RDONLY);
ro = 1;
}
if (fd < 0) {
pr_err("Could not open backing file: %s", nopt);
goto err;
}
if (fstat(fd, &sbuf) < 0) {
pr_err("Could not stat backing file %s", nopt);
goto err;
}
/*
* Deal with raw devices
*/
size = sbuf.st_size;
sectsz = DEV_BSIZE;
psectsz = psectoff = 0;
if (S_ISBLK(sbuf.st_mode)) {
/* get size */
err_code = ioctl(fd, BLKGETSIZE, &sz);
if (err_code) {
pr_err("error %d getting block size!\n",
err_code);
size = sbuf.st_size; /* set default value */
} else {
size = sz * DEV_BSIZE; /* DEV_BSIZE is 512 on Linux */
}
if (!err_code || err_code == EFBIG) {
err_code = ioctl(fd, BLKGETSIZE64, &b);
if (err_code || b == 0 || b == sz)
size = b * DEV_BSIZE;
else
size = b;
}
DPRINTF(("block partition size is 0x%lx\n", size));
/* get sector size, 512 on Linux */
sectsz = DEV_BSIZE;
DPRINTF(("block partition sector size is 0x%x\n", sectsz));
/* get physical sector size */
err_code = ioctl(fd, BLKPBSZGET, &psectsz);
if (err_code) {
pr_err("error %d getting physical sectsz!\n",
err_code);
psectsz = DEV_BSIZE; /* set default physical size */
}
DPRINTF(("block partition physical sector size is 0x%lx\n",
psectsz));
if (candiscard) {
err_code = ioctl(fd, BLKDISCARD, probe_arg);
if (err_code) {
WPRINTF(("not support DISCARD\n"));
candiscard = 0;
}
}
} else {
if (size < DEV_BSIZE || (size & (DEV_BSIZE - 1))) {
WPRINTF(("%s size not corret, should be multiple of %d\n",
nopt, DEV_BSIZE));
goto err;
}
psectsz = sbuf.st_blksize;
}
if (ssopt != 0) {
if (!powerof2(ssopt) || !powerof2(pssopt) || ssopt < 512 ||
ssopt > pssopt) {
pr_err("Invalid sector size %d/%d\n",
ssopt, pssopt);
goto err;
}
/*
* Some backend drivers (e.g. cd0, ada0) require that the I/O
* size be a multiple of the device's sector size.
*
* Validate that the emulated sector size complies with this
* requirement.
*/
if (S_ISCHR(sbuf.st_mode)) {
if (ssopt < sectsz || (ssopt % sectsz) != 0) {
pr_err("Sector size %d incompatible with underlying device sector size %d\n",
ssopt, sectsz);
goto err;
}
}
sectsz = ssopt;
psectsz = pssopt;
psectoff = 0;
}
bc = calloc(1, sizeof(struct blockif_ctxt));
if (bc == NULL) {
pr_err("calloc");
goto err;
}
if (sub_file_assign) {
DPRINTF(("sector size is %d\n", sectsz));
bc->sub_file_assign = 1;
bc->sub_file_start_lba = sub_file_start_lba * sectsz;
size = sub_file_size * sectsz;
DPRINTF(("Validating sub file...\n"));
err_code = sub_file_validate(bc, fd, ro, bc->sub_file_start_lba,
size);
if (err_code < 0) {
pr_err("subfile range specified not valid!\n");
exit(1);
}
DPRINTF(("Validated done!\n"));
} else {
/* normal case */
bc->sub_file_assign = 0;
bc->sub_file_start_lba = 0;
}
bc->fd = fd;
bc->isblk = S_ISBLK(sbuf.st_mode);
bc->candiscard = candiscard;
if (candiscard) {
bc->max_discard_sectors =
(max_discard_sectors != -1) ?
max_discard_sectors : (size / DEV_BSIZE);
bc->max_discard_seg =
(max_discard_seg != -1) ? max_discard_seg : 1;
bc->discard_sector_alignment =
(discard_sector_alignment != -1) ? discard_sector_alignment : 0;
}
bc->rdonly = ro;
bc->size = size;
bc->sectsz = sectsz;
bc->psectsz = psectsz;
bc->psectoff = psectoff;
bc->wce = writeback;
pthread_mutex_init(&bc->mtx, NULL);
pthread_cond_init(&bc->cond, NULL);
TAILQ_INIT(&bc->freeq);
TAILQ_INIT(&bc->pendq);
TAILQ_INIT(&bc->busyq);
for (i = 0; i < BLOCKIF_MAXREQ; i++) {
bc->reqs[i].status = BST_FREE;
TAILQ_INSERT_HEAD(&bc->freeq, &bc->reqs[i], link);
}
for (i = 0; i < BLOCKIF_NUMTHR; i++) {
if (snprintf(tname, sizeof(tname), "blk-%s-%d",
ident, i) >= sizeof(tname)) {
pr_err("blk thread name too long");
}
pthread_create(&bc->btid[i], NULL, blockif_thr, bc);
pthread_setname_np(bc->btid[i], tname);
}
/* free strdup memory */
if (nopt) {
free(nopt);
nopt = NULL;
}
return bc;
err:
/* handle failure case: free strdup memory*/
if (nopt)
free(nopt);
if (fd >= 0)
close(fd);
return NULL;
}
static int
blockif_request(struct blockif_ctxt *bc, struct blockif_req *breq,
enum blockop op)
{
int err;
err = 0;
pthread_mutex_lock(&bc->mtx);
if (!TAILQ_EMPTY(&bc->freeq)) {
/*
* Enqueue and inform the block i/o thread
* that there is work available
*/
if (blockif_enqueue(bc, breq, op))
pthread_cond_signal(&bc->cond);
} else {
/*
* Callers are not allowed to enqueue more than
* the specified blockif queue limit. Return an
* error to indicate that the queue length has been
* exceeded.
*/
err = E2BIG;
}
pthread_mutex_unlock(&bc->mtx);
return err;
}
int
blockif_read(struct blockif_ctxt *bc, struct blockif_req *breq)
{
return blockif_request(bc, breq, BOP_READ);
}
int
blockif_write(struct blockif_ctxt *bc, struct blockif_req *breq)
{
return blockif_request(bc, breq, BOP_WRITE);
}
int
blockif_flush(struct blockif_ctxt *bc, struct blockif_req *breq)
{
return blockif_request(bc, breq, BOP_FLUSH);
}
int
blockif_discard(struct blockif_ctxt *bc, struct blockif_req *breq)
{
return blockif_request(bc, breq, BOP_DISCARD);
}
int
blockif_cancel(struct blockif_ctxt *bc, struct blockif_req *breq)
{
struct blockif_elem *be;
pthread_mutex_lock(&bc->mtx);
/*
* Check pending requests.
*/
TAILQ_FOREACH(be, &bc->pendq, link) {
if (be->req == breq)
break;
}
if (be != NULL) {
/*
* Found it.
*/
blockif_complete(bc, be);
pthread_mutex_unlock(&bc->mtx);
return 0;
}
/*
* Check in-flight requests.
*/
TAILQ_FOREACH(be, &bc->busyq, link) {
if (be->req == breq)
break;
}
if (be == NULL) {
/*
* Didn't find it.
*/
pthread_mutex_unlock(&bc->mtx);
return -1;
}
/*
* Interrupt the processing thread to force it return
* prematurely via it's normal callback path.
*/
while (be->status == BST_BUSY) {
struct blockif_sig_elem bse, *old_head;
pthread_mutex_init(&bse.mtx, NULL);
pthread_cond_init(&bse.cond, NULL);
bse.pending = 1;
do {
old_head = blockif_bse_head;
bse.next = old_head;
} while (!__sync_bool_compare_and_swap((uintptr_t *)&
blockif_bse_head,
(uintptr_t)old_head,
(uintptr_t)&bse));
pthread_kill(be->tid, SIGCONT);
pthread_mutex_lock(&bse.mtx);
while (bse.pending)
pthread_cond_wait(&bse.cond, &bse.mtx);
pthread_mutex_unlock(&bse.mtx);
}
pthread_mutex_unlock(&bc->mtx);
/*
* The processing thread has been interrupted. Since it's not
* clear if the callback has been invoked yet, return EBUSY.
*/
return -EBUSY;
}
int
blockif_close(struct blockif_ctxt *bc)
{
void *jval;
int i;
sub_file_unlock(bc);
/*
* Stop the block i/o thread
*/
pthread_mutex_lock(&bc->mtx);
bc->closing = 1;
pthread_cond_broadcast(&bc->cond);
pthread_mutex_unlock(&bc->mtx);
for (i = 0; i < BLOCKIF_NUMTHR; i++)
pthread_join(bc->btid[i], &jval);
/* XXX Cancel queued i/o's ??? */
/*
* Release resources
*/
close(bc->fd);
free(bc);
return 0;
}
/*
* Return virtual C/H/S values for a given block. Use the algorithm
* outlined in the VHD specification to calculate values.
*/
void
blockif_chs(struct blockif_ctxt *bc, uint16_t *c, uint8_t *h, uint8_t *s)
{
off_t sectors; /* total sectors of the block dev */
off_t hcyl; /* cylinders times heads */
uint16_t secpt; /* sectors per track */
uint8_t heads;
sectors = bc->size / bc->sectsz;
/* Clamp the size to the largest possible with CHS */
if (sectors > 65535UL*16*255)
sectors = 65535UL*16*255;
if (sectors >= 65536UL*16*63) {
secpt = 255;
heads = 16;
hcyl = sectors / secpt;
} else {
secpt = 17;
hcyl = sectors / secpt;
heads = (hcyl + 1023) / 1024;
if (heads < 4)
heads = 4;
if (hcyl >= (heads * 1024) || heads > 16) {
secpt = 31;
heads = 16;
hcyl = sectors / secpt;
}
if (hcyl >= (heads * 1024)) {
secpt = 63;
heads = 16;
hcyl = sectors / secpt;
}
}
*c = hcyl / heads;
*h = heads;
*s = secpt;
}
/*
* Accessors
*/
off_t
blockif_size(struct blockif_ctxt *bc)
{
return bc->size;
}
int
blockif_sectsz(struct blockif_ctxt *bc)
{
return bc->sectsz;
}
void
blockif_psectsz(struct blockif_ctxt *bc, int *size, int *off)
{
*size = bc->psectsz;
*off = bc->psectoff;
}
int
blockif_queuesz(struct blockif_ctxt *bc)
{
return (BLOCKIF_MAXREQ - 1);
}
int
blockif_is_ro(struct blockif_ctxt *bc)
{
return bc->rdonly;
}
int
blockif_candiscard(struct blockif_ctxt *bc)
{
return bc->candiscard;
}
int
blockif_max_discard_sectors(struct blockif_ctxt *bc)
{
return bc->max_discard_sectors;
}
int
blockif_max_discard_seg(struct blockif_ctxt *bc)
{
return bc->max_discard_seg;
}
int
blockif_discard_sector_alignment(struct blockif_ctxt *bc)
{
return bc->discard_sector_alignment;
}
uint8_t
blockif_get_wce(struct blockif_ctxt *bc)
{
return bc->wce;
}
void
blockif_set_wce(struct blockif_ctxt *bc, uint8_t wce)
{
bc->wce = wce;
}
int
blockif_flush_all(struct blockif_ctxt *bc)
{
int err;
err=0;
if (fsync(bc->fd))
err = errno;
return err;
}