WebSVN – HelenOS – Blame – /trunk/uspace/srv/fs/fat/fat.c

Rev	Author	Line No.	Line
2006	decky	1	/*
2071	jermar	2	* Copyright (c) 2006 Martin Decky
2529	jermar	3	* Copyright (c) 2007 Jakub Jermar
2006	decky	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	/**
2529	jermar	35	* @file fat.c
		36	* @brief FAT file system driver for HelenOS.
2006	decky	37	*/
		38
2627	jermar	39	#include "fat.h"
2529	jermar	40	#include <ipc/ipc.h>
		41	#include <ipc/services.h>
2531	jermar	42	#include <async.h>
2529	jermar	43	#include <errno.h>
		44	#include <unistd.h>
2536	jermar	45	#include <stdio.h>
2643	jermar	46	#include <libfs.h>
2529	jermar	47	#include "../../vfs/vfs.h"
2006	decky	48
2532	jermar	49
2529	jermar	50	vfs_info_t fat_vfs_info = {
		51	.name = "fat",
		52	.ops = {
		53	[IPC_METHOD_TO_VFS_OP(VFS_REGISTER)] = VFS_OP_DEFINED,
		54	[IPC_METHOD_TO_VFS_OP(VFS_MOUNT)] = VFS_OP_DEFINED,
		55	[IPC_METHOD_TO_VFS_OP(VFS_UNMOUNT)] = VFS_OP_DEFINED,
		56	[IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] = VFS_OP_DEFINED,
		57	[IPC_METHOD_TO_VFS_OP(VFS_OPEN)] = VFS_OP_DEFINED,
		58	[IPC_METHOD_TO_VFS_OP(VFS_CREATE)] = VFS_OP_DEFINED,
		59	[IPC_METHOD_TO_VFS_OP(VFS_CLOSE)] = VFS_OP_DEFINED,
		60	[IPC_METHOD_TO_VFS_OP(VFS_READ)] = VFS_OP_DEFINED,
		61	[IPC_METHOD_TO_VFS_OP(VFS_WRITE)] = VFS_OP_NULL,
		62	[IPC_METHOD_TO_VFS_OP(VFS_SEEK)] = VFS_OP_DEFAULT
		63	}
		64	};
		65
2643	jermar	66	fs_reg_t fat_reg;
2543	jermar	67
2536	jermar	68	/**
		69	* This connection fibril processes VFS requests from VFS.
		70	*
		71	* In order to support simultaneous VFS requests, our design is as follows.
		72	* The connection fibril accepts VFS requests from VFS. If there is only one
		73	* instance of the fibril, VFS will need to serialize all VFS requests it sends
		74	* to FAT. To overcome this bottleneck, VFS can send FAT the IPC_M_CONNECT_ME_TO
		75	* call. In that case, a new connection fibril will be created, which in turn
		76	* will accept the call. Thus, a new phone will be opened for VFS.
		77	*
		78	* There are few issues with this arrangement. First, VFS can run out of
		79	* available phones. In that case, VFS can close some other phones or use one
2627	jermar	80	* phone for more serialized requests. Similarily, FAT can refuse to duplicate
2536	jermar	81	* the connection. VFS should then just make use of already existing phones and
		82	* route its requests through them. To avoid paying the fibril creation price
		83	* upon each request, FAT might want to keep the connections open after the
		84	* request has been completed.
2531	jermar	85	*/
2536	jermar	86	static void fat_connection(ipc_callid_t iid, ipc_call_t *icall)
2531	jermar	87	{
2536	jermar	88	if (iid) {
		89	/*
		90	* This only happens for connections opened by
		91	* IPC_M_CONNECT_ME_TO calls as opposed to callback connections
		92	* created by IPC_M_CONNECT_TO_ME.
		93	*/
2619	jermar	94	ipc_answer_0(iid, EOK);
2536	jermar	95	}
		96
		97	dprintf("VFS-FAT connection established.\n");
2531	jermar	98	while (1) {
		99	ipc_callid_t callid;
		100	ipc_call_t call;
		101
		102	callid = async_get_call(&call);
2536	jermar	103	switch (IPC_GET_METHOD(call)) {
2627	jermar	104	case VFS_REGISTER:
		105	ipc_answer_0(callid, EOK);
		106	break;
		107	case VFS_LOOKUP:
		108	fat_lookup(callid, &call);
		109	break;
2536	jermar	110	default:
2619	jermar	111	ipc_answer_0(callid, ENOTSUP);
2536	jermar	112	break;
		113	}
2531	jermar	114	}
		115	}
		116
2006	decky	117	int main(int argc, char **argv)
		118	{
2532	jermar	119	int vfs_phone;
2529	jermar	120
2532	jermar	121	printf("FAT: HelenOS FAT file system server.\n");
		122
2635	cejka	123	vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0, 0);
2532	jermar	124	while (vfs_phone < EOK) {
2529	jermar	125	usleep(10000);
2635	cejka	126	vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0, 0);
2529	jermar	127	}
		128
2643	jermar	129	int rc;
		130	rc = fs_register(vfs_phone, &fat_reg, &fat_vfs_info, fat_connection);
2531	jermar	131	if (rc != EOK) {
2643	jermar	132	printf("Failed to register the FAT file system (%d)\n", rc);
2531	jermar	133	return rc;
		134	}
2536	jermar	135
2644	jermar	136	dprintf("FAT filesystem registered, fs_handle=%d.\n",
		137	fat_reg.fs_handle);
2532	jermar	138
2568	jermar	139	async_manager();
2534	jermar	140	/* not reached */
2006	decky	141	return 0;
		142	}
		143
		144	/**
		145	* @}
		146	*/

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/fs/fat/fat.c @ 2591 – Rev 2644