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/*
media-filesystem library, io routines
tridge@samba.org, January 2001
released under the Gnu GPL v2
*/
#include "mfs.h"
static int readahead_enabled = 0;
static int vserver = -1;
static int need_bswap = 0;
void vstream_mfs_readahead(int set)
{
readahead_enabled = set;
}
static void vserver_read_req(u32 sec, u32 count)
{
struct vserver_cmd cmd;
cmd.command = htonl(MFS_CMD_READ);
cmd.param1 = htonl(sec);
cmd.param2 = htonl(count);
vstream_write_all(vserver, &cmd, sizeof(cmd));
}
static void vserver_receive(void *buf, u32 count)
{
count <<= SECTOR_SHIFT;
vstream_read_all(vserver, buf, count);
}
#define RA_BLOCKS 256
#define RA_MIN 256
void vserver_vstream_read_sectors(void *buf, u32 sec, u32 count)
{
static struct mfs_run readahead;
u32 discard, coming;
if (count == 0)
return;
discard = coming = 0;
if (sec >= readahead.start && sec < readahead.start + readahead.len) {
discard = sec - readahead.start;
coming = readahead.len - discard;
if (coming <= count) {
readahead.len = 0;
} else {
readahead.start = sec + count;
readahead.len -= discard + count;
}
} else {
discard = readahead.len;
coming = 0;
readahead.len = 0;
}
if (coming < count) {
u32 nreq = count - coming;
if (readahead_enabled && nreq < RA_BLOCKS) {
readahead.start = sec + count;
readahead.len = RA_BLOCKS - nreq;
nreq = RA_BLOCKS;
}
vserver_read_req(sec + coming, nreq);
}
if (readahead.len <= RA_MIN && readahead_enabled) {
if (readahead.len == 0)
readahead.start = sec + count;
vserver_read_req(readahead.start + readahead.len, RA_BLOCKS);
readahead.len += RA_BLOCKS;
}
if (discard) {
void *buf2 = malloc(discard << SECTOR_SHIFT);
vserver_receive(buf2, discard);
free(buf2);
}
vserver_receive(buf, count);
if (need_bswap) {
u16 *v = (u16 *)buf;
int i;
for (i=0;i<count<<(SECTOR_SHIFT-1);i++)
v[i] = ntohs(v[i]);
}
}
void vstream_io_need_bswap(int set)
{
need_bswap = set;
}
/* read bytes from a sector, handling partial sectors */
void vstream_mfs_read_partial(void *buf, u32 sec, u32 size)
{
char tmp[SECTOR_SIZE];
if (size >= SECTOR_SIZE) {
u32 n = size / SECTOR_SIZE;
vserver_vstream_read_sectors(buf, sec, n);
buf += n*SECTOR_SIZE;
size -= n*SECTOR_SIZE;
sec += n;
}
if (size == 0) return;
vserver_vstream_read_sectors(tmp, sec, 1);
memcpy(buf, tmp, size);
}
void vstream_set_socket_fd(int fd)
{
vserver = fd;
}
int vstream_open_socket(char *addy)
{
if (vserver < 0)
vserver = vstream_vstream_open_socket_out(addy, VSERVER_PORT);
if (vserver < 0) {
vstream_error("Failed to connect to %s\n", addy);
return 1;
}
return 0;
}
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