[PATCH] v9fs: transport modules
This part of the patch contains transport routines. Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com> Signed-off-by: Latchesar Ionkov <lucho@ionkov.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Eric Van Hensbergen
committed by
Linus Torvalds
Linus Torvalds
parent
b8cf945b31
commit
426cc91aa6
440
fs/9p/mux.c
Normal file
440
fs/9p/mux.c
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/*
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* linux/fs/9p/mux.c
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*
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* Protocol Multiplexer
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*
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* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
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* Copyright (C) 2004 by Latchesar Ionkov <lucho@ionkov.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to:
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* Free Software Foundation
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* 51 Franklin Street, Fifth Floor
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* Boston, MA 02111-1301 USA
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*
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/kthread.h>
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#include <linux/idr.h>
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#include "debug.h"
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#include "v9fs.h"
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#include "9p.h"
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#include "transport.h"
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#include "conv.h"
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#include "mux.h"
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/**
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* dprintcond - print condition of session info
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* @v9ses: session info structure
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* @req: RPC request structure
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*
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*/
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static inline int
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dprintcond(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
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{
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dprintk(DEBUG_MUX, "condition: %d, %p\n", v9ses->transport->status,
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req->rcall);
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return 0;
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}
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/**
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* xread - force read of a certain number of bytes
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* @v9ses: session info structure
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* @ptr: pointer to buffer
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* @sz: number of bytes to read
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*
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* Chuck Cranor CS-533 project1
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*/
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static int xread(struct v9fs_session_info *v9ses, void *ptr, unsigned long sz)
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{
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int rd = 0;
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int ret = 0;
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while (rd < sz) {
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ret = v9ses->transport->read(v9ses->transport, ptr, sz - rd);
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if (ret <= 0) {
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dprintk(DEBUG_ERROR, "xread errno %d\n", ret);
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return ret;
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}
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rd += ret;
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ptr += ret;
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}
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return (rd);
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}
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/**
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* read_message - read a full 9P2000 fcall packet
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* @v9ses: session info structure
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* @rcall: fcall structure to read into
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* @rcalllen: size of fcall buffer
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*
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*/
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static int
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read_message(struct v9fs_session_info *v9ses,
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struct v9fs_fcall *rcall, int rcalllen)
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{
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unsigned char buf[4];
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void *data;
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int size = 0;
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int res = 0;
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res = xread(v9ses, buf, sizeof(buf));
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if (res < 0) {
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dprintk(DEBUG_ERROR,
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"Reading of count field failed returned: %d\n", res);
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return res;
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}
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if (res < 4) {
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dprintk(DEBUG_ERROR,
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"Reading of count field failed returned: %d\n", res);
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return -EIO;
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}
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size = buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24);
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dprintk(DEBUG_MUX, "got a packet count: %d\n", size);
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/* adjust for the four bytes of size */
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size -= 4;
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if (size > v9ses->maxdata) {
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dprintk(DEBUG_ERROR, "packet too big: %d\n", size);
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return -E2BIG;
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}
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data = kmalloc(size, GFP_KERNEL);
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if (!data) {
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eprintk(KERN_WARNING, "out of memory\n");
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return -ENOMEM;
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}
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res = xread(v9ses, data, size);
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if (res < size) {
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dprintk(DEBUG_ERROR, "Reading of fcall failed returned: %d\n",
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res);
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kfree(data);
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return res;
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}
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/* we now have an in-memory string that is the reply.
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* deserialize it. There is very little to go wrong at this point
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* save for v9fs_alloc errors.
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*/
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res = v9fs_deserialize_fcall(v9ses, size, data, v9ses->maxdata,
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rcall, rcalllen);
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kfree(data);
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if (res < 0)
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return res;
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return 0;
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}
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/**
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* v9fs_recv - receive an RPC response for a particular tag
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* @v9ses: session info structure
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* @req: RPC request structure
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*
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*/
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static int v9fs_recv(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
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{
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int ret = 0;
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dprintk(DEBUG_MUX, "waiting for response: %d\n", req->tcall->tag);
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ret = wait_event_interruptible(v9ses->read_wait,
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((v9ses->transport->status != Connected) ||
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(req->rcall != 0) || dprintcond(v9ses, req)));
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dprintk(DEBUG_MUX, "got it: rcall %p\n", req->rcall);
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if (v9ses->transport->status == Disconnected)
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return -ECONNRESET;
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if (ret == 0) {
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spin_lock(&v9ses->muxlock);
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list_del(&req->next);
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spin_unlock(&v9ses->muxlock);
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}
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return ret;
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}
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/**
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* v9fs_send - send a 9P request
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* @v9ses: session info structure
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* @req: RPC request to send
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*
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*/
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static int v9fs_send(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
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{
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int ret = -1;
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void *data = NULL;
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struct v9fs_fcall *tcall = req->tcall;
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data = kmalloc(v9ses->maxdata + V9FS_IOHDRSZ, GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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tcall->size = 0; /* enforce size recalculation */
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ret =
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v9fs_serialize_fcall(v9ses, tcall, data,
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v9ses->maxdata + V9FS_IOHDRSZ);
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if (ret < 0)
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goto free_data;
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spin_lock(&v9ses->muxlock);
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list_add(&req->next, &v9ses->mux_fcalls);
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spin_unlock(&v9ses->muxlock);
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dprintk(DEBUG_MUX, "sending message: tag %d size %d\n", tcall->tag,
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tcall->size);
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ret = v9ses->transport->write(v9ses->transport, data, tcall->size);
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if (ret != tcall->size) {
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spin_lock(&v9ses->muxlock);
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list_del(&req->next);
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kfree(req->rcall);
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spin_unlock(&v9ses->muxlock);
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if (ret >= 0)
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ret = -EREMOTEIO;
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} else
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ret = 0;
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free_data:
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kfree(data);
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return ret;
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}
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/**
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* v9fs_mux_rpc - send a request, receive a response
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* @v9ses: session info structure
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* @tcall: fcall to send
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* @rcall: buffer to place response into
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*
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*/
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long
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v9fs_mux_rpc(struct v9fs_session_info *v9ses, struct v9fs_fcall *tcall,
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struct v9fs_fcall **rcall)
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{
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int tid = -1;
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struct v9fs_fcall *fcall = NULL;
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struct v9fs_rpcreq req;
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int ret = -1;
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if (!v9ses)
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return -EINVAL;
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if (rcall)
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*rcall = NULL;
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if (tcall->id != TVERSION) {
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tid = v9fs_get_idpool(&v9ses->tidpool);
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if (tid < 0)
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return -ENOMEM;
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}
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tcall->tag = tid;
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req.tcall = tcall;
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req.rcall = NULL;
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ret = v9fs_send(v9ses, &req);
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if (ret < 0) {
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if (tcall->id != TVERSION)
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v9fs_put_idpool(tid, &v9ses->tidpool);
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dprintk(DEBUG_MUX, "error %d\n", ret);
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return ret;
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}
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ret = v9fs_recv(v9ses, &req);
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fcall = req.rcall;
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dprintk(DEBUG_MUX, "received: tag=%x, ret=%d\n", tcall->tag, ret);
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if (ret == -ERESTARTSYS) {
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if (v9ses->transport->status != Disconnected
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&& tcall->id != TFLUSH) {
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unsigned long flags;
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dprintk(DEBUG_MUX, "flushing the tag: %d\n",
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tcall->tag);
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clear_thread_flag(TIF_SIGPENDING);
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v9fs_t_flush(v9ses, tcall->tag);
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spin_lock_irqsave(¤t->sighand->siglock, flags);
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recalc_sigpending();
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spin_unlock_irqrestore(¤t->sighand->siglock,
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flags);
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dprintk(DEBUG_MUX, "flushing done\n");
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}
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goto release_req;
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} else if (ret < 0)
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goto release_req;
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if (!fcall)
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ret = -EIO;
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else {
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if (fcall->id == RERROR) {
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ret = v9fs_errstr2errno(fcall->params.rerror.error);
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if (ret == 0) { /* string match failed */
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if (fcall->params.rerror.errno)
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ret = -(fcall->params.rerror.errno);
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else
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ret = -ESERVERFAULT;
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}
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} else if (fcall->id != tcall->id + 1) {
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dprintk(DEBUG_ERROR,
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"fcall mismatch: expected %d, got %d\n",
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tcall->id + 1, fcall->id);
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ret = -EIO;
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}
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}
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release_req:
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if (tcall->id != TVERSION)
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v9fs_put_idpool(tid, &v9ses->tidpool);
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if (rcall)
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*rcall = fcall;
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else
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kfree(fcall);
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return ret;
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}
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/**
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* v9fs_recvproc - kproc to handle demultiplexing responses
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* @data: session info structure
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*
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*/
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static int v9fs_recvproc(void *data)
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{
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struct v9fs_session_info *v9ses = (struct v9fs_session_info *)data;
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struct v9fs_fcall *rcall = NULL;
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struct v9fs_rpcreq *rptr;
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struct v9fs_rpcreq *req;
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struct v9fs_rpcreq *rreq;
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int err = 0;
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allow_signal(SIGKILL);
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set_current_state(TASK_INTERRUPTIBLE);
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complete(&v9ses->proccmpl);
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while (!kthread_should_stop() && err >= 0) {
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req = rptr = rreq = NULL;
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rcall = kmalloc(v9ses->maxdata + V9FS_IOHDRSZ, GFP_KERNEL);
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if (!rcall) {
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eprintk(KERN_ERR, "no memory for buffers\n");
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break;
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}
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err = read_message(v9ses, rcall, v9ses->maxdata + V9FS_IOHDRSZ);
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if (err < 0) {
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kfree(rcall);
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break;
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}
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spin_lock(&v9ses->muxlock);
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list_for_each_entry_safe(rreq, rptr, &v9ses->mux_fcalls, next) {
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if (rreq->tcall->tag == rcall->tag) {
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req = rreq;
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req->rcall = rcall;
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break;
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}
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}
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if (req && (req->tcall->id == TFLUSH)) {
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struct v9fs_rpcreq *treq = NULL;
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list_for_each_entry_safe(treq, rptr, &v9ses->mux_fcalls, next) {
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if (treq->tcall->tag ==
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req->tcall->params.tflush.oldtag) {
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list_del(&rptr->next);
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kfree(treq->rcall);
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break;
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}
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}
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}
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spin_unlock(&v9ses->muxlock);
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if (!req) {
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dprintk(DEBUG_ERROR,
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"unexpected response: id %d tag %d\n",
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rcall->id, rcall->tag);
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kfree(rcall);
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}
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wake_up_all(&v9ses->read_wait);
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set_current_state(TASK_INTERRUPTIBLE);
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}
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/* Inform all pending processes about the failure */
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wake_up_all(&v9ses->read_wait);
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if (signal_pending(current))
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complete(&v9ses->proccmpl);
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dprintk(DEBUG_MUX, "recvproc: end\n");
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v9ses->recvproc = NULL;
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return err >= 0;
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}
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/**
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* v9fs_mux_init - initialize multiplexer (spawn kproc)
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* @v9ses: session info structure
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* @dev_name: mount device information (to create unique kproc)
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*
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*/
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int v9fs_mux_init(struct v9fs_session_info *v9ses, const char *dev_name)
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{
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char procname[60];
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strncpy(procname, dev_name, sizeof(procname));
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procname[sizeof(procname) - 1] = 0;
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init_waitqueue_head(&v9ses->read_wait);
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init_completion(&v9ses->fcread);
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init_completion(&v9ses->proccmpl);
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spin_lock_init(&v9ses->muxlock);
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INIT_LIST_HEAD(&v9ses->mux_fcalls);
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v9ses->recvproc = NULL;
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v9ses->curfcall = NULL;
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v9ses->recvproc = kthread_create(v9fs_recvproc, v9ses,
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"v9fs_recvproc %s", procname);
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if (IS_ERR(v9ses->recvproc)) {
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eprintk(KERN_ERR, "cannot create receiving thread\n");
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v9fs_session_close(v9ses);
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return -ECONNABORTED;
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}
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wake_up_process(v9ses->recvproc);
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wait_for_completion(&v9ses->proccmpl);
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return 0;
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}
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