WebSVN – HelenOS – Blame – /branches/network/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
2529	jermar	39	#include <ipc/ipc.h>
		40	#include <ipc/services.h>
2531	jermar	41	#include <async.h>
2529	jermar	42	#include <errno.h>
		43	#include <unistd.h>
2536	jermar	44	#include <stdio.h>
2543	jermar	45	#include <as.h>>
2529	jermar	46	#include "../../vfs/vfs.h"
2006	decky	47
2532	jermar	48	#define dprintf(...) printf(__VA_ARGS__)
		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
2543	jermar	66	uint8_t *plb_ro = NULL;
		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
		80	* phone for more serialized requests. Similarly, FAT can refuse to duplicate
		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	*/
		94	ipc_answer_fast(iid, EOK, 0, 0);
		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)) {
		104	default:
		105	ipc_answer_fast(callid, ENOTSUP, 0, 0);
		106	break;
		107	}
2531	jermar	108	}
		109	}
		110
2006	decky	111	int main(int argc, char **argv)
		112	{
2532	jermar	113	int vfs_phone;
2529	jermar	114
2532	jermar	115	printf("FAT: HelenOS FAT file system server.\n");
		116
2529	jermar	117	vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0);
2532	jermar	118	while (vfs_phone < EOK) {
2529	jermar	119	usleep(10000);
		120	vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0);
		121	}
		122
2531	jermar	123	/*
		124	* Tell VFS that we are here and want to get registered.
		125	* We use the async framework because VFS will answer the request
		126	* out-of-order, when it knows that the operation succeeded or failed.
		127	*/
		128	ipc_call_t answer;
		129	aid_t req = async_send_2(vfs_phone, VFS_REGISTER, 0, 0, &answer);
2529	jermar	130
2531	jermar	131	/*
		132	* Send our VFS info structure to VFS.
		133	*/
		134	int rc = ipc_data_send(vfs_phone, &fat_vfs_info, sizeof(fat_vfs_info));
		135	if (rc != EOK) {
		136	async_wait_for(req, NULL);
		137	return rc;
		138	}
		139
		140	/*
		141	* Ask VFS for callback connection.
		142	*/
		143	ipcarg_t phonehash;
		144	ipc_connect_to_me(vfs_phone, 0, 0, &phonehash);
		145
2536	jermar	146	/*
2543	jermar	147	* Allocate piece of address space for PLB.
		148	*/
		149	plb_ro = as_get_mappable_page(PLB_SIZE);
		150	if (!plb_ro) {
		151	async_wait_for(req, NULL);
		152	return ENOMEM;
		153	}
		154
		155	/*
		156	* Request sharing the Path Lookup Buffer with VFS.
		157	*/
		158	rc = ipc_call_sync_3(vfs_phone, IPC_M_AS_AREA_RECV, plb_ro, PLB_SIZE, 0,
		159	NULL, NULL, NULL);
		160	if (rc) {
		161	async_wait_for(req, NULL);
		162	return rc;
		163	}
		164
		165	/*
2536	jermar	166	* Create a connection fibril to handle the callback connection.
		167	*/
2531	jermar	168	async_new_connection(phonehash, 0, NULL, fat_connection);
2536	jermar	169
		170	/*
		171	* Tell the async framework that other connections are to be handled by
		172	* the same connection fibril as well.
		173	*/
		174	async_set_client_connection(fat_connection);
2532	jermar	175
		176	/*
		177	* Pick up the answer for the request to the VFS_REQUEST call.
		178	*/
		179	async_wait_for(req, NULL);
		180	dprintf("FAT filesystem registered.\n");
2533	jermar	181
2536	jermar	182	async_create_manager();
		183
2533	jermar	184	/*
2534	jermar	185	* TODO: Interestingly, if we merely return, the only thread dies.
2536	jermar	186	* If the only thread dies, the whole task is destroyed.
		187	* Prevent the thread from exiting when there are active fibrils.
2533	jermar	188	*/
2534	jermar	189	fibril_schedule_next_adv(FIBRIL_FROM_DEAD);
		190	/* not reached */
		191
2006	decky	192	return 0;
		193	}
		194
		195	/**
		196	* @}
		197	*/

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