source: mainline/uspace/srv/fs/fat/fat.c@ 8ccd2ea

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 8ccd2ea was cad9c72, checked in by Jakub Jermar <jakub@…>, 17 years ago

Make a distinction between VFS operations that are common to VFS and FS
implementations, operations that are VFS only and operations that are FS
implementations only.

  • Property mode set to 100644
File size: 4.6 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 <stdio.h>
46#include <libfs.h>
47#include "../../vfs/vfs.h"
48
49
50vfs_info_t fat_vfs_info = {
51 .name = "fat",
52 .ops = {
53 [IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] = VFS_OP_DEFINED,
54 [IPC_METHOD_TO_VFS_OP(VFS_OPEN)] = VFS_OP_DEFINED,
55 [IPC_METHOD_TO_VFS_OP(VFS_CLOSE)] = VFS_OP_DEFINED,
56 [IPC_METHOD_TO_VFS_OP(VFS_READ)] = VFS_OP_DEFINED,
57 [IPC_METHOD_TO_VFS_OP(VFS_WRITE)] = VFS_OP_NULL,
58 [IPC_METHOD_TO_VFS_OP(VFS_TRUNCATE)] = VFS_OP_NULL,
59 [IPC_METHOD_TO_VFS_OP(VFS_RENAME)] = VFS_OP_NULL,
60 [IPC_METHOD_TO_VFS_OP(VFS_OPENDIR)] = VFS_OP_NULL,
61 [IPC_METHOD_TO_VFS_OP(VFS_READDIR)] = VFS_OP_NULL,
62 [IPC_METHOD_TO_VFS_OP(VFS_CLOSEDIR)] = VFS_OP_NULL,
63 [IPC_METHOD_TO_VFS_OP(VFS_UNLINK)] = VFS_OP_NULL,
64 [IPC_METHOD_TO_VFS_OP(VFS_MOUNT)] = VFS_OP_NULL,
65 [IPC_METHOD_TO_VFS_OP(VFS_UNMOUNT)] = VFS_OP_NULL,
66 }
67};
68
69fs_reg_t fat_reg;
70
71/**
72 * This connection fibril processes VFS requests from VFS.
73 *
74 * In order to support simultaneous VFS requests, our design is as follows.
75 * The connection fibril accepts VFS requests from VFS. If there is only one
76 * instance of the fibril, VFS will need to serialize all VFS requests it sends
77 * to FAT. To overcome this bottleneck, VFS can send FAT the IPC_M_CONNECT_ME_TO
78 * call. In that case, a new connection fibril will be created, which in turn
79 * will accept the call. Thus, a new phone will be opened for VFS.
80 *
81 * There are few issues with this arrangement. First, VFS can run out of
82 * available phones. In that case, VFS can close some other phones or use one
83 * phone for more serialized requests. Similarily, FAT can refuse to duplicate
84 * the connection. VFS should then just make use of already existing phones and
85 * route its requests through them. To avoid paying the fibril creation price
86 * upon each request, FAT might want to keep the connections open after the
87 * request has been completed.
88 */
89static void fat_connection(ipc_callid_t iid, ipc_call_t *icall)
90{
91 if (iid) {
92 /*
93 * This only happens for connections opened by
94 * IPC_M_CONNECT_ME_TO calls as opposed to callback connections
95 * created by IPC_M_CONNECT_TO_ME.
96 */
97 ipc_answer_0(iid, EOK);
98 }
99
100 dprintf("VFS-FAT connection established.\n");
101 while (1) {
102 ipc_callid_t callid;
103 ipc_call_t call;
104
105 callid = async_get_call(&call);
106 switch (IPC_GET_METHOD(call)) {
107 case VFS_LOOKUP:
108 fat_lookup(callid, &call);
109 break;
110 default:
111 ipc_answer_0(callid, ENOTSUP);
112 break;
113 }
114 }
115}
116
117int main(int argc, char **argv)
118{
119 int vfs_phone;
120
121 printf("FAT: HelenOS FAT file system server.\n");
122
123 vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0, 0);
124 while (vfs_phone < EOK) {
125 usleep(10000);
126 vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0, 0);
127 }
128
129 int rc;
130 rc = fs_register(vfs_phone, &fat_reg, &fat_vfs_info, fat_connection);
131 if (rc != EOK) {
132 printf("Failed to register the FAT file system (%d)\n", rc);
133 return rc;
134 }
135
136 dprintf("FAT filesystem registered, fs_handle=%d.\n",
137 fat_reg.fs_handle);
138
139 async_manager();
140 /* not reached */
141 return 0;
142}
143
144/**
145 * @}
146 */
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