source: branches/samba-3.3.x/source/modules/vfs_readahead.c@ 374

Last change on this file since 374 was 206, checked in by Herwig Bauernfeind, 17 years ago

Import Samba 3.3 branch at 3.0.0 level (psmedley's port)
File size: 5.6 KB
Line 
1/*
2 * Copyright (c) Jeremy Allison 2007.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 3 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
16 */
17
18#include "includes.h"
19
20struct readahead_data {
21 SMB_OFF_T off_bound;
22 SMB_OFF_T len;
23 bool didmsg;
24};
25
26/*
27 * This module copes with Vista AIO read requests on Linux
28 * by detecting the initial 0x80000 boundary reads and causing
29 * the buffer cache to be filled in advance.
30 */
31
32/*******************************************************************
33 sendfile wrapper that does readahead/posix_fadvise.
34*******************************************************************/
35
36static ssize_t readahead_sendfile(struct vfs_handle_struct *handle,
37 int tofd,
38 files_struct *fromfsp,
39 const DATA_BLOB *header,
40 SMB_OFF_T offset,
41 size_t count)
42{
43 struct readahead_data *rhd = (struct readahead_data *)handle->data;
44
45 if ( offset % rhd->off_bound == 0) {
46#if defined(HAVE_LINUX_READAHEAD)
47 int err = readahead(fromfsp->fh->fd, offset, (size_t)rhd->len);
48 DEBUG(10,("readahead_sendfile: readahead on fd %u, offset %llu, len %u returned %d\n",
49 (unsigned int)fromfsp->fh->fd,
50 (unsigned long long)offset,
51 (unsigned int)rhd->len,
52 err ));
53#elif defined(HAVE_POSIX_FADVISE)
54 int err = posix_fadvise(fromfsp->fh->fd, offset, (off_t)rhd->len, POSIX_FADV_WILLNEED);
55 DEBUG(10,("readahead_sendfile: posix_fadvise on fd %u, offset %llu, len %u returned %d\n",
56 (unsigned int)fromfsp->fh->fd,
57 (unsigned long long)offset,
58 (unsigned int)rhd->len,
59 err ));
60#else
61 if (!rhd->didmsg) {
62 DEBUG(0,("readahead_sendfile: no readahead on this platform\n"));
63 rhd->didmsg = True;
64 }
65#endif
66 }
67 return SMB_VFS_NEXT_SENDFILE(handle,
68 tofd,
69 fromfsp,
70 header,
71 offset,
72 count);
73}