#include "includes.h"
#define READAHEAD_MIN (128 * 1024)
#define READAHEAD_MAX (100 * 1024 * 1024)
#define MODULE "cacheprime"
static int module_debug;
static ssize_t g_readsz = 0;
static void * g_readbuf = NULL;
static BOOL prime_cache(
struct vfs_handle_struct * handle,
files_struct * fsp,
int fd,
SMB_OFF_T offset,
size_t count)
{
SMB_OFF_T * last;
ssize_t nread;
last = VFS_ADD_FSP_EXTENSION(handle, fsp, SMB_OFF_T);
if (!last) {
return False;
}
if (*last == -1) {
return False;
}
if ((*last + g_readsz) > (offset + count)) {
return False;
}
DEBUG(module_debug,
("%s: doing readahead of %lld bytes at %lld for %s\n",
MODULE, (long long)g_readsz, (long long)*last,
fsp->fsp_name));
nread = sys_pread(fd, g_readbuf, g_readsz, *last);
if (nread < 0) {
*last = -1;
return False;
}
*last += nread;
return True;
}
static int cprime_connect(
struct vfs_handle_struct * handle,
const char * service,
const char * user)
{
module_debug = lp_parm_int(SNUM(handle->conn), MODULE, "debug", 100);
if (g_readbuf) {
return SMB_VFS_NEXT_CONNECT(handle, service, user);
}
g_readsz = conv_str_size(lp_parm_const_string(SNUM(handle->conn),
MODULE, "rsize", NULL));
if (g_readsz < READAHEAD_MIN) {
DEBUG(module_debug, ("%s: %ld bytes of readahead "
"requested, using minimum of %u\n",
MODULE, (long)g_readsz, READAHEAD_MIN));
g_readsz = READAHEAD_MIN;
} else if (g_readsz > READAHEAD_MAX) {
DEBUG(module_debug, ("%s: %ld bytes of readahead "
"requested, using maximum of %u\n",
MODULE, (long)g_readsz, READAHEAD_MAX));
g_readsz = READAHEAD_MAX;
}
if ((g_readbuf = SMB_MALLOC(g_readsz)) == NULL) {
g_readsz = 0;
}
return SMB_VFS_NEXT_CONNECT(handle, service, user);
}
static ssize_t cprime_sendfile(
struct vfs_handle_struct * handle,
int tofd,
files_struct * fsp,
int fromfd,
const DATA_BLOB * header,
SMB_OFF_T offset,
size_t count)
{
if (g_readbuf && offset == 0) {
prime_cache(handle, fsp, fromfd, offset, count);
}
return SMB_VFS_NEXT_SENDFILE(handle, tofd, fsp, fromfd,
header, offset, count);
}
static ssize_t cprime_read(
vfs_handle_struct * handle,
files_struct * fsp,
int fd,
void * data,
size_t count)
{
SMB_OFF_T offset;
offset = SMB_VFS_LSEEK(fsp, fd, 0, SEEK_CUR);
if (offset >= 0 && g_readbuf) {
prime_cache(handle, fsp, fd, offset, count);
SMB_VFS_LSEEK(fsp, fd, offset, SEEK_SET);
}
return SMB_VFS_NEXT_READ(handle, fsp, fd, data, count);
}
static ssize_t cprime_pread(
vfs_handle_struct * handle,
files_struct * fsp,
int fd,
void * data,
size_t count,
SMB_OFF_T offset)
{
if (g_readbuf) {
prime_cache(handle, fsp, fd, offset, count);
}
return SMB_VFS_NEXT_PREAD(handle, fsp, fd, data, count, offset);
}
static vfs_op_tuple cprime_ops [] =
{
{SMB_VFS_OP(cprime_sendfile),
SMB_VFS_OP_SENDFILE, SMB_VFS_LAYER_TRANSPARENT},
{SMB_VFS_OP(cprime_pread),
SMB_VFS_OP_PREAD, SMB_VFS_LAYER_TRANSPARENT},
{SMB_VFS_OP(cprime_read),
SMB_VFS_OP_READ, SMB_VFS_LAYER_TRANSPARENT},
{SMB_VFS_OP(cprime_connect),
SMB_VFS_OP_CONNECT, SMB_VFS_LAYER_TRANSPARENT},
{SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
};
NTSTATUS vfs_cacheprime_init(void);
NTSTATUS vfs_cacheprime_init(void)
{
return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, MODULE, cprime_ops);
}