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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 2 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "includes.h"
#if !defined(HAVE_LINUX_READAHEAD) && !defined(HAVE_POSIX_FADVISE)
static BOOL didmsg;
#endif
/*
* 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.
*/
static unsigned long get_offset_boundary(struct vfs_handle_struct *handle)
{
SMB_OFF_T off_bound = conv_str_size(lp_parm_const_string(SNUM(handle->conn),
"readahead",
"offset",
NULL));
if (off_bound == 0) {
off_bound = 0x80000;
}
return (unsigned long)off_bound;
}
static unsigned long get_offset_length(struct vfs_handle_struct *handle, unsigned long def_val)
{
SMB_OFF_T len = conv_str_size(lp_parm_const_string(SNUM(handle->conn),
"readahead",
"length",
NULL));
if (len == 0) {
len = def_val;
}
return (unsigned long)len;
}
static ssize_t readahead_sendfile(struct vfs_handle_struct *handle,
int tofd,
files_struct *fsp,
int fromfd,
const DATA_BLOB *header,
SMB_OFF_T offset,
size_t count)
{
unsigned long off_bound = get_offset_boundary(handle);
if ( offset % off_bound == 0) {
unsigned long len = get_offset_length(handle, off_bound);
#if defined(HAVE_LINUX_READAHEAD)
int err = readahead(fromfd, offset, (size_t)len);
DEBUG(10,("readahead_sendfile: readahead on fd %u, offset %llu, len %u returned %d\n",
(unsigned int)fromfd,
(unsigned long long)offset,
(unsigned int)len,
err ));
#elif defined(HAVE_POSIX_FADVISE)
int err = posix_fadvise(fromfd, offset, (off_t)len, POSIX_FADV_WILLNEED);
DEBUG(10,("readahead_sendfile: posix_fadvise on fd %u, offset %llu, len %u returned %d\n",
(unsigned int)fromfd,
(unsigned long long)offset,
(unsigned int)len,
err ));
#else
if (!didmsg) {
DEBUG(0,("readahead_sendfile: no readahead on this platform\n"));
didmsg = True;
}
#endif
}
return SMB_VFS_NEXT_SENDFILE(handle,
tofd,
fsp,
fromfd,
header,
offset,
count);
}
static ssize_t readahead_pread(vfs_handle_struct *handle,
files_struct *fsp,
int fd,
void *data,
size_t count,
SMB_OFF_T offset)
{
unsigned long off_bound = get_offset_boundary(handle);
if ( offset % off_bound == 0) {
unsigned long len = get_offset_length(handle, off_bound);
#if defined(HAVE_LINUX_READAHEAD)
int err = readahead(fd, offset, (size_t)len);
DEBUG(10,("readahead_pread: readahead on fd %u, offset %llu, len %u returned %d\n",
(unsigned int)fd,
(unsigned long long)offset,
(unsigned int)len,
err ));
#elif defined(HAVE_POSIX_FADVISE)
int err = posix_fadvise(fromfd, offset, (off_t)len, POSIX_FADV_WILLNEED);
DEBUG(10,("readahead_pread: posix_fadvise on fd %u, offset %llu, len %u returned %d\n",
(unsigned int)fd,
(unsigned long long)offset,
(unsigned int)len,
(err ));
#else
if (!didmsg) {
DEBUG(0,("readahead_pread: no readahead on this platform\n"));
didmsg = True;
}
#endif
}
return SMB_VFS_NEXT_PREAD(handle, fsp, fd, data, count, offset);
}
static vfs_op_tuple readahead_ops [] =
{
{SMB_VFS_OP(readahead_sendfile), SMB_VFS_OP_SENDFILE, SMB_VFS_LAYER_TRANSPARENT},
{SMB_VFS_OP(readahead_pread), SMB_VFS_OP_PREAD, SMB_VFS_LAYER_TRANSPARENT},
{SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
};
NTSTATUS vfs_readahead_init(void);
NTSTATUS vfs_readahead_init(void)
{
return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "readahead", readahead_ops);
}
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