source: mainline/uspace/srv/fs/fat/fat.c@ 5581b469

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 5581b469 was 5581b469, checked in by Jakub Jermar <jakub@…>, 15 years ago

Introduce new boolean properties into vfs_info_t.

The FS can set concurrent_read_write to true if it is ready to handle
concurrent reads and writes from/to one node.

The FS can set write_retains_size if its write method never modifies the
size of the node.
  • Property mode set to 100644
File size: 4.9 KB
Line 
1/*
2 * Copyright (c) 2006 Martin Decky
3 * Copyright (c) 2008 Jakub Jermar
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * - Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * - Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * - The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30/** @addtogroup fs
31 * @{
32 */
33
34/**
35 * @file fat.c
36 * @brief FAT file system driver for HelenOS.
37 */
38
39#include "fat.h"
40#include <ipc/ipc.h>
41#include <ipc/services.h>
42#include <async.h>
43#include <errno.h>
44#include <unistd.h>
45#include <task.h>
46#include <stdio.h>
47#include <libfs.h>
48#include "../../vfs/vfs.h"
49
50#define NAME "fat"
51
52vfs_info_t fat_vfs_info = {
53 .name = NAME,
54 .concurrent_read_write = false,
55 .write_retains_size = false,
56};
57
58fs_reg_t fat_reg;
59
60/**
61 * This connection fibril processes VFS requests from VFS.
62 *
63 * In order to support simultaneous VFS requests, our design is as follows.
64 * The connection fibril accepts VFS requests from VFS. If there is only one
65 * instance of the fibril, VFS will need to serialize all VFS requests it sends
66 * to FAT. To overcome this bottleneck, VFS can send FAT the IPC_M_CONNECT_ME_TO
67 * call. In that case, a new connection fibril will be created, which in turn
68 * will accept the call. Thus, a new phone will be opened for VFS.
69 *
70 * There are few issues with this arrangement. First, VFS can run out of
71 * available phones. In that case, VFS can close some other phones or use one
72 * phone for more serialized requests. Similarily, FAT can refuse to duplicate
73 * the connection. VFS should then just make use of already existing phones and
74 * route its requests through them. To avoid paying the fibril creation price
75 * upon each request, FAT might want to keep the connections open after the
76 * request has been completed.
77 */
78static void fat_connection(ipc_callid_t iid, ipc_call_t *icall)
79{
80 if (iid) {
81 /*
82 * This only happens for connections opened by
83 * IPC_M_CONNECT_ME_TO calls as opposed to callback connections
84 * created by IPC_M_CONNECT_TO_ME.
85 */
86 ipc_answer_0(iid, EOK);
87 }
88
89 dprintf(NAME ": connection opened\n");
90 while (1) {
91 ipc_callid_t callid;
92 ipc_call_t call;
93
94 callid = async_get_call(&call);
95 switch (IPC_GET_METHOD(call)) {
96 case IPC_M_PHONE_HUNGUP:
97 return;
98 case VFS_OUT_MOUNTED:
99 fat_mounted(callid, &call);
100 break;
101 case VFS_OUT_MOUNT:
102 fat_mount(callid, &call);
103 break;
104 case VFS_OUT_UNMOUNTED:
105 fat_unmounted(callid, &call);
106 break;
107 case VFS_OUT_UNMOUNT:
108 fat_unmount(callid, &call);
109 break;
110 case VFS_OUT_LOOKUP:
111 fat_lookup(callid, &call);
112 break;
113 case VFS_OUT_READ:
114 fat_read(callid, &call);
115 break;
116 case VFS_OUT_WRITE:
117 fat_write(callid, &call);
118 break;
119 case VFS_OUT_TRUNCATE:
120 fat_truncate(callid, &call);
121 break;
122 case VFS_OUT_STAT:
123 fat_stat(callid, &call);
124 break;
125 case VFS_OUT_CLOSE:
126 fat_close(callid, &call);
127 break;
128 case VFS_OUT_DESTROY:
129 fat_destroy(callid, &call);
130 break;
131 case VFS_OUT_OPEN_NODE:
132 fat_open_node(callid, &call);
133 break;
134 case VFS_OUT_SYNC:
135 fat_sync(callid, &call);
136 break;
137 default:
138 ipc_answer_0(callid, ENOTSUP);
139 break;
140 }
141 }
142}
143
144int main(int argc, char **argv)
145{
146 int vfs_phone;
147 int rc;
148
149 printf(NAME ": HelenOS FAT file system server\n");
150
151 rc = fat_idx_init();
152 if (rc != EOK)
153 goto err;
154
155 vfs_phone = ipc_connect_me_to_blocking(PHONE_NS, SERVICE_VFS, 0, 0);
156 if (vfs_phone < EOK) {
157 printf(NAME ": failed to connect to VFS\n");
158 return -1;
159 }
160
161 rc = fs_register(vfs_phone, &fat_reg, &fat_vfs_info, fat_connection);
162 if (rc != EOK) {
163 fat_idx_fini();
164 goto err;
165 }
166
167 printf(NAME ": Accepting connections\n");
168 task_retval(0);
169 async_manager();
170 /* not reached */
171 return 0;
172
173err:
174 printf(NAME ": Failed to register file system (%d)\n", rc);
175 return rc;
176}
177
178/**
179 * @}
180 */
Note: See TracBrowser for help on using the repository browser.