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}
74
75/*******************************************************************
76 pread wrapper that does readahead/posix_fadvise.
77*******************************************************************/
78
79static ssize_t readahead_pread(vfs_handle_struct *handle,
80				files_struct *fsp,
81				void *data,
82				size_t count,
83				SMB_OFF_T offset)
84{
85	struct readahead_data *rhd = (struct readahead_data *)handle->data;
86
87	if ( offset % rhd->off_bound == 0) {
88#if defined(HAVE_LINUX_READAHEAD)
89		int err = readahead(fsp->fh->fd, offset, (size_t)rhd->len);
90		DEBUG(10,("readahead_pread: readahead on fd %u, offset %llu, len %u returned %d\n",
91			(unsigned int)fsp->fh->fd,
92			(unsigned long long)offset,
93			(unsigned int)rhd->len,
94			err ));
95#elif defined(HAVE_POSIX_FADVISE)
96		int err = posix_fadvise(fsp->fh->fd, offset, (off_t)rhd->len, POSIX_FADV_WILLNEED);
97		DEBUG(10,("readahead_pread: posix_fadvise on fd %u, offset %llu, len %u returned %d\n",
98			(unsigned int)fsp->fh->fd,
99			(unsigned long long)offset,
100			(unsigned int)rhd->len,
101			err ));
102#else
103		if (!rhd->didmsg) {
104			DEBUG(0,("readahead_pread: no readahead on this platform\n"));
105			rhd->didmsg = True;
106		}
107#endif
108        }
109        return SMB_VFS_NEXT_PREAD(handle, fsp, data, count, offset);
110}
111
112/*******************************************************************
113 Directly called from main smbd when freeing handle.
114*******************************************************************/
115
116static void free_readahead_data(void **pptr)
117{
118	SAFE_FREE(*pptr);
119}
120
121/*******************************************************************
122 Allocate the handle specific data so we don't call the expensive
123 conv_str_size function for each sendfile/pread.
124*******************************************************************/
125
126static int readahead_connect(struct vfs_handle_struct *handle,
127				const char *service,
128				const char *user)
129{
130	struct readahead_data *rhd;
131	int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
132
133	if (ret < 0) {
134		return ret;
135	}
136	rhd = SMB_MALLOC_P(struct readahead_data);
137	if (!rhd) {
138		SMB_VFS_NEXT_DISCONNECT(handle);
139		DEBUG(0,("readahead_connect: out of memory\n"));
140		return -1;
141	}
142	ZERO_STRUCTP(rhd);
143
144	rhd->didmsg = False;
145	rhd->off_bound = conv_str_size(lp_parm_const_string(SNUM(handle->conn),
146						"readahead",
147						"offset",
148						NULL));
149	if (rhd->off_bound == 0) {
150		rhd->off_bound = 0x80000;
151	}
152	rhd->len = conv_str_size(lp_parm_const_string(SNUM(handle->conn),
153						"readahead",
154						"length",
155						NULL));
156	if (rhd->len == 0) {
157		rhd->len = rhd->off_bound;
158	}
159
160	handle->data = (void *)rhd;
161	handle->free_data = free_readahead_data;
162	return 0;
163}
164
165static struct vfs_fn_pointers vfs_readahead_fns = {
166	.sendfile = readahead_sendfile,
167	.pread = readahead_pread,
168	.connect_fn = readahead_connect
169};
170
171/*******************************************************************
172 Module initialization boilerplate.
173*******************************************************************/
174
175NTSTATUS vfs_readahead_init(void);
176NTSTATUS vfs_readahead_init(void)
177{
178	return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "readahead",
179				&vfs_readahead_fns);
180}
181