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/*
* Copyright (c) Jeremy Allison 2007.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "system/filesys.h"
#include "smbd/smbd.h"
#if defined(HAVE_LINUX_READAHEAD) && ! defined(HAVE_READAHEAD_DECL)
ssize_t readahead(int fd, off_t offset, size_t count);
#endif
struct readahead_data {
off_t off_bound;
off_t len;
bool didmsg;
};
/*
* This module copes with Vista AIO read requests on Linux
* by detecting the initial 0x80000 boundary reads and causing
* the buffer cache to be filled in advance.
*/
/*******************************************************************
sendfile wrapper that does readahead/posix_fadvise.
*******************************************************************/
static ssize_t readahead_sendfile(struct vfs_handle_struct *handle,
int tofd,
files_struct *fromfsp,
const DATA_BLOB *header,
off_t offset,
size_t count)
{
struct readahead_data *rhd = (struct readahead_data *)handle->data;
if ( offset % rhd->off_bound == 0) {
#if defined(HAVE_LINUX_READAHEAD)
int err = readahead(fromfsp->fh->fd, offset, (size_t)rhd->len);
DEBUG(10,("readahead_sendfile: readahead on fd %u, offset %llu, len %u returned %d\n",
(unsigned int)fromfsp->fh->fd,
(unsigned long long)offset,
(unsigned int)rhd->len,
err ));
#elif defined(HAVE_POSIX_FADVISE)
int err = posix_fadvise(fromfsp->fh->fd, offset, (off_t)rhd->len, POSIX_FADV_WILLNEED);
DEBUG(10,("readahead_sendfile: posix_fadvise on fd %u, offset %llu, len %u returned %d\n",
(unsigned int)fromfsp->fh->fd,
(unsigned long long)offset,
(unsigned int)rhd->len,
err ));
#else
if (!rhd->didmsg) {
DEBUG(0,("readahead_sendfile: no readahead on this platform\n"));
rhd->didmsg = True;
}
#endif
}
return SMB_VFS_NEXT_SENDFILE(handle,
tofd,
fromfsp,
header,
offset,
count);
}
/*******************************************************************
pread wrapper that does readahead/posix_fadvise.
*******************************************************************/
static ssize_t readahead_pread(vfs_handle_struct *handle,
files_struct *fsp,
void *data,
size_t count,
off_t offset)
{
struct readahead_data *rhd = (struct readahead_data *)handle->data;
if ( offset % rhd->off_bound == 0) {
#if defined(HAVE_LINUX_READAHEAD)
int err = readahead(fsp->fh->fd, offset, (size_t)rhd->len);
DEBUG(10,("readahead_pread: readahead on fd %u, offset %llu, len %u returned %d\n",
(unsigned int)fsp->fh->fd,
(unsigned long long)offset,
(unsigned int)rhd->len,
err ));
#elif defined(HAVE_POSIX_FADVISE)
int err = posix_fadvise(fsp->fh->fd, offset, (off_t)rhd->len, POSIX_FADV_WILLNEED);
DEBUG(10,("readahead_pread: posix_fadvise on fd %u, offset %llu, len %u returned %d\n",
(unsigned int)fsp->fh->fd,
(unsigned long long)offset,
(unsigned int)rhd->len,
err ));
#else
if (!rhd->didmsg) {
DEBUG(0,("readahead_pread: no readahead on this platform\n"));
rhd->didmsg = True;
}
#endif
}
return SMB_VFS_NEXT_PREAD(handle, fsp, data, count, offset);
}
/*******************************************************************
Directly called from main smbd when freeing handle.
*******************************************************************/
static void free_readahead_data(void **pptr)
{
SAFE_FREE(*pptr);
}
/*******************************************************************
Allocate the handle specific data so we don't call the expensive
conv_str_size function for each sendfile/pread.
*******************************************************************/
static int readahead_connect(struct vfs_handle_struct *handle,
const char *service,
const char *user)
{
struct readahead_data *rhd;
int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
if (ret < 0) {
return ret;
}
rhd = SMB_MALLOC_P(struct readahead_data);
if (!rhd) {
SMB_VFS_NEXT_DISCONNECT(handle);
DEBUG(0,("readahead_connect: out of memory\n"));
return -1;
}
ZERO_STRUCTP(rhd);
rhd->didmsg = False;
rhd->off_bound = conv_str_size(lp_parm_const_string(SNUM(handle->conn),
"readahead",
"offset",
NULL));
if (rhd->off_bound == 0) {
rhd->off_bound = 0x80000;
}
rhd->len = conv_str_size(lp_parm_const_string(SNUM(handle->conn),
"readahead",
"length",
NULL));
if (rhd->len == 0) {
rhd->len = rhd->off_bound;
}
handle->data = (void *)rhd;
handle->free_data = free_readahead_data;
return 0;
}
static struct vfs_fn_pointers vfs_readahead_fns = {
.sendfile_fn = readahead_sendfile,
.pread_fn = readahead_pread,
.connect_fn = readahead_connect
};
/*******************************************************************
Module initialization boilerplate.
*******************************************************************/
NTSTATUS vfs_readahead_init(TALLOC_CTX *);
NTSTATUS vfs_readahead_init(TALLOC_CTX *ctx)
{
return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "readahead",
&vfs_readahead_fns);
}
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