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
2690	jermar	3	* Copyright (c) 2008 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	};
		53
2643	jermar	54	fs_reg_t fat_reg;
2543	jermar	55
2536	jermar	56	/**
		57	* This connection fibril processes VFS requests from VFS.
		58	*
		59	* In order to support simultaneous VFS requests, our design is as follows.
		60	* The connection fibril accepts VFS requests from VFS. If there is only one
		61	* instance of the fibril, VFS will need to serialize all VFS requests it sends
		62	* to FAT. To overcome this bottleneck, VFS can send FAT the IPC_M_CONNECT_ME_TO
		63	* call. In that case, a new connection fibril will be created, which in turn
		64	* will accept the call. Thus, a new phone will be opened for VFS.
		65	*
		66	* There are few issues with this arrangement. First, VFS can run out of
		67	* available phones. In that case, VFS can close some other phones or use one
2627	jermar	68	* phone for more serialized requests. Similarily, FAT can refuse to duplicate
2536	jermar	69	* the connection. VFS should then just make use of already existing phones and
		70	* route its requests through them. To avoid paying the fibril creation price
		71	* upon each request, FAT might want to keep the connections open after the
		72	* request has been completed.
2531	jermar	73	*/
2536	jermar	74	static void fat_connection(ipc_callid_t iid, ipc_call_t *icall)
2531	jermar	75	{
2536	jermar	76	if (iid) {
		77	/*
		78	* This only happens for connections opened by
		79	* IPC_M_CONNECT_ME_TO calls as opposed to callback connections
		80	* created by IPC_M_CONNECT_TO_ME.
		81	*/
2619	jermar	82	ipc_answer_0(iid, EOK);
2536	jermar	83	}
		84
		85	dprintf("VFS-FAT connection established.\n");
2531	jermar	86	while (1) {
		87	ipc_callid_t callid;
		88	ipc_call_t call;
		89
		90	callid = async_get_call(&call);
2536	jermar	91	switch (IPC_GET_METHOD(call)) {
3110	jermar	92	case VFS_MOUNTED:
		93	fat_mounted(callid, &call);
		94	break;
		95	case VFS_MOUNT:
		96	fat_mount(callid, &call);
		97	break;
2627	jermar	98	case VFS_LOOKUP:
		99	fat_lookup(callid, &call);
		100	break;
3307	jermar	101	case VFS_READ:
		102	fat_read(callid, &call);
		103	break;
3497	jermar	104	case VFS_WRITE:
		105	fat_write(callid, &call);
		106	break;
3546	jermar	107	case VFS_TRUNCATE:
		108	fat_truncate(callid, &call);
		109	break;
3636	jermar	110	case VFS_DESTROY:
		111	fat_destroy(callid, &call);
		112	break;
2536	jermar	113	default:
2619	jermar	114	ipc_answer_0(callid, ENOTSUP);
2536	jermar	115	break;
		116	}
2531	jermar	117	}
		118	}
		119
2006	decky	120	int main(int argc, char **argv)
		121	{
2532	jermar	122	int vfs_phone;
3110	jermar	123	int rc;
2529	jermar	124
3882	decky	125	printf("fat: HelenOS FAT file system server.\n");
2532	jermar	126
3110	jermar	127	rc = fat_idx_init();
		128	if (rc != EOK)
		129	goto err;
		130
4007	decky	131	vfs_phone = ipc_connect_me_to_blocking(PHONE_NS, SERVICE_VFS, 0, 0);
		132	if (vfs_phone < EOK) {
		133	printf("fat: failed to connect to VFS\n");
		134	return -1;
2529	jermar	135	}
		136
2643	jermar	137	rc = fs_register(vfs_phone, &fat_reg, &fat_vfs_info, fat_connection);
2531	jermar	138	if (rc != EOK) {
3110	jermar	139	fat_idx_fini();
		140	goto err;
2531	jermar	141	}
2536	jermar	142
2644	jermar	143	dprintf("FAT filesystem registered, fs_handle=%d.\n",
		144	fat_reg.fs_handle);
2532	jermar	145
2568	jermar	146	async_manager();
2534	jermar	147	/* not reached */
2006	decky	148	return 0;
3110	jermar	149
		150	err:
		151	printf("Failed to register the FAT file system (%d)\n", rc);
		152	return rc;
2006	decky	153	}
		154
		155	/**
		156	* @}
		157	*/

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/fs/fat/fat.c – Rev 4007