- 根目录:
- fs
- cifs
- transport.c
/*
* fs/cifs/transport.c
*
* Copyright (C) International Business Machines Corp., 2002,2008
* Author(s): Steve French (sfrench@us.ibm.com)
* Jeremy Allison (jra@samba.org) 2006.
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/gfp.h>
#include <linux/wait.h>
#include <linux/net.h>
#include <linux/delay.h>
#include <linux/freezer.h>
#include <linux/tcp.h>
#include <linux/highmem.h>
#include <asm/uaccess.h>
#include <asm/processor.h>
#include <linux/mempool.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
void
cifs_wake_up_task(struct mid_q_entry *mid)
{
wake_up_process(mid->callback_data);
}
struct mid_q_entry *
AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
{
struct mid_q_entry *temp;
if (server == NULL) {
cifs_dbg(VFS, "Null TCP session in AllocMidQEntry\n");
return NULL;
}
temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
if (temp == NULL)
return temp;
else {
memset(temp, 0, sizeof(struct mid_q_entry));
temp->mid = get_mid(smb_buffer);
temp->pid = current->pid;
temp->command = cpu_to_le16(smb_buffer->Command);
cifs_dbg(FYI, "For smb_command %d\n", smb_buffer->Command);
/* do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
/* when mid allocated can be before when sent */
temp->when_alloc = jiffies;
temp->server = server;
/*
* The default is for the mid to be synchronous, so the
* default callback just wakes up the current task.
*/
temp->callback = cifs_wake_up_task;
temp->callback_data = current;
}
atomic_inc(&midCount);
temp->mid_state = MID_REQUEST_ALLOCATED;
return temp;
}
void
DeleteMidQEntry(struct mid_q_entry *midEntry)
{
#ifdef CONFIG_CIFS_STATS2
__le16 command = midEntry->server->vals->lock_cmd;
unsigned long now;
#endif
midEntry->mid_state = MID_FREE;
atomic_dec(&midCount);
if (midEntry->large_buf)
cifs_buf_release(midEntry->resp_buf);
else
cifs_small_buf_release(midEntry->resp_buf);
#ifdef CONFIG_CIFS_STATS2
now = jiffies;
/* commands taking longer than one second are indications that
something is wrong, unless it is quite a slow link or server */
if ((now - midEntry->when_alloc) > HZ) {
if ((cifsFYI & CIFS_TIMER) && (midEntry->command != command)) {
printk(KERN_DEBUG " CIFS slow rsp: cmd %d mid %llu",
midEntry->command, midEntry->mid);
printk(" A: 0x%lx S: 0x%lx R: 0x%lx\n",
now - midEntry->when_alloc,
now - midEntry->when_sent,
now - midEntry->when_received);
}
}
#endif
mempool_free(midEntry, cifs_mid_poolp);
}
void
cifs_delete_mid(struct mid_q_entry *mid)
{
spin_lock(&GlobalMid_Lock);
list_del(&mid->qhead);
spin_unlock(&GlobalMid_Lock);
DeleteMidQEntry(mid);
}
/*
* smb_send_kvec - send an array of kvecs to the server
* @server: Server to send the data to
* @iov: Pointer to array of kvecs
* @n_vec: length of kvec array
* @sent: amount of data sent on socket is stored here
*
* Our basic "send data to server" function. Should be called with srv_mutex
* held. The caller is responsible for handling the results.
*/
static int
smb_send_kvec(struct TCP_Server_Info *server, struct kvec *iov, size_t n_vec,
size_t *sent)
{
int rc = 0;
int i = 0;
struct msghdr smb_msg;
unsigned int remaining;
size_t first_vec = 0;
struct socket *ssocket = server->ssocket;
*sent = 0;
smb_msg.msg_name = (struct sockaddr *) &server->dstaddr;
smb_msg.msg_namelen = sizeof(struct sockaddr);
smb_msg.msg_control = NULL;
smb_msg.msg_controllen = 0;
if (server->noblocksnd)
smb_msg.msg_flags = MSG_DONTWAIT + MSG_NOSIGNAL;
else
smb_msg.msg_flags = MSG_NOSIGNAL;
remaining = 0;
for (i = 0; i < n_vec; i++)
remaining += iov[i].iov_len;
i = 0;
while (remaining) {
/*
* If blocking send, we try 3 times, since each can block
* for 5 seconds. For nonblocking we have to try more
* but wait increasing amounts of time allowing time for
* socket to clear. The overall time we wait in either
* case to send on the socket is about 15 seconds.
* Similarly we wait for 15 seconds for a response from
* the server in SendReceive[2] for the server to send
* a response back for most types of requests (except
* SMB Write past end of file which can be slow, and
* blocking lock operations). NFS waits slightly longer
* than CIFS, but this can make it take longer for
* nonresponsive servers to be detected and 15 seconds
* is more than enough time for modern networks to
* send a packet. In most cases if we fail to send
* after the retries we will kill the socket and
* reconnect which may clear the network problem.
*/
rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
n_vec - first_vec, remaining);
if (rc == -EAGAIN) {
i++;
if (i >= 14 || (!server->noblocksnd && (i > 2))) {
cifs_dbg(VFS, "sends on sock %p stuck for 15 seconds\n",
ssocket);
rc = -EAGAIN;
break;
}
msleep(1 << i);
continue;
}
if (rc < 0)
break;
/* send was at least partially successful */
*sent += rc;
if (rc == remaining) {
remaining = 0;
break;
}
if (rc > remaining) {
cifs_dbg(VFS, "sent %d requested %d\n", rc, remaining);
break;
}
if (rc == 0) {
/* should never happen, letting socket clear before
retrying is our only obvious option here */
cifs_dbg(VFS, "tcp sent no data\n");
msleep(500);
continue;
}
remaining -= rc;
/* the line below resets i */
for (i = first_vec; i < n_vec; i++) {
if (iov[i].iov_len) {
if (rc > iov[i].iov_len) {
rc -= iov[i].iov_len;
iov[i].iov_len = 0;
} else {
iov[i].iov_base += rc;
iov[i].iov_len -= rc;
first_vec = i;
break;
}
}
}
i = 0; /* in case we get ENOSPC on the next send */
rc = 0;
}
return rc;
}
/**
* rqst_page_to_kvec - Turn a slot in the smb_rqst page array into a kvec
* @rqst: pointer to smb_rqst
* @idx: index into the array of the page
* @iov: pointer to struct kvec that will hold the result
*
* Helper function to convert a slot in the rqst->rq_pages array into a kvec.
* The page will be kmapped and the address placed into iov_base. The length
* will then be adjusted according to the ptailoff.
*/
void
cifs_rqst_page_to_kvec(struct smb_rqst *rqst, unsigned int idx,
struct kvec *iov)
{
/*
* FIXME: We could avoid this kmap altogether if we used
* kernel_sendpage instead of kernel_sendmsg. That will only
* work if signing is disabled though as sendpage inlines the
* page directly into the fraglist. If userspace modifies the
* page after we calculate the signature, then the server will
* reject it and may break the connection. kernel_sendmsg does
* an extra copy of the data and avoids that issue.
*/
iov->iov_base = kmap(rqst->rq_pages[idx]);
/* if last page, don't send beyond this offset into page */
if (idx == (rqst->rq_npages - 1))
iov->iov_len = rqst->rq_tailsz;
else
iov->iov_len = rqst->rq_pagesz;
}
static unsigned long
rqst_len(struct smb_rqst *rqst)
{
unsigned int i;
struct kvec *iov = rqst->rq_iov;
unsigned long buflen = 0;
/* total up iov array first */
for (i = 0; i < rqst->rq_nvec; i++)
buflen += iov[i].iov_len;
/* add in the page array if there is one */
if (rqst->rq_npages) {
buflen += rqst->rq_pagesz * (rqst->rq_npages - 1);
buflen += rqst->rq_tailsz;
}
return buflen;
}
static int
smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
{
int rc;
struct kvec *iov = rqst->rq_iov;
int n_vec = rqst->rq_nvec;
unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);
unsigned long send_length;
unsigned int i;
size_t total_len = 0, sent;
struct socket *ssocket = server->ssocket;
int val = 1;
if (ssocket == NULL)
return -ENOTSOCK;
/* sanity check send length */
send_length = rqst_len(rqst);
if (send_length != smb_buf_length + 4) {
WARN(1, "Send length mismatch(send_length=%lu smb_buf_length=%u)\n",
send_length, smb_buf_length);
return -EIO;
}
cifs_dbg(FYI, "Sending smb: smb_len=%u\n", smb_buf_length);
dump_smb(iov[0].iov_base, iov[0].iov_len);
/* cork the socket */
kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
(char *)&val, sizeof(val));
rc = smb_send_kvec(server, iov, n_vec, &sent);
if (rc < 0)
goto uncork;
total_len += sent;
/* now walk the page array and send each page in it */
for (i = 0; i < rqst->rq_npages; i++) {
struct kvec p_iov;
cifs_rqst_page_to_kvec(rqst, i, &p_iov);
rc = smb_send_kvec(server, &p_iov, 1, &sent);
kunmap(rqst->rq_pages[i]);
if (rc < 0)
break;
total_len += sent;
}
uncork:
/* uncork it */
val = 0;
kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
(char *)&val, sizeof(val));
if ((total_len > 0) && (total_len != smb_buf_length + 4)) {
cifs_dbg(FYI, "partial send (wanted=%u sent=%zu): terminating session\n",
smb_buf_length + 4, total_len);
/*
* If we have only sent part of an SMB then the next SMB could
* be taken as the remainder of this one. We need to kill the
* socket so the server throws away the partial SMB
*/
server->tcpStatus = CifsNeedReconnect;
}
if (rc < 0 && rc != -EINTR)
cifs_dbg(VFS, "Error %d sending data on socket to server\n",
rc);
else
rc = 0;
return rc;
}
static int
smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
{
struct smb_rqst rqst = { .rq_iov = iov,
.rq_nvec = n_vec };
return smb_send_rqst(server, &rqst);
}
int
smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
unsigned int smb_buf_length)
{
struct kvec iov;
iov.iov_base = smb_buffer;
iov.iov_len = smb_buf_length + 4;
return smb_sendv(server, &iov, 1);
}
static int
wait_for_free_credits(struct TCP_Server_Info *server, const int timeout,
int *credits)
{
int rc;
spin_lock(&server->req_lock);
if (timeout == CIFS_ASYNC_OP) {
/* oplock breaks must not be held up */
server->in_flight++;
*credits -= 1;
spin_unlock(&server->req_lock);
return 0;
}
while (1) {
if (*credits <= 0) {
spin_unlock(&server->req_lock);
cifs_num_waiters_inc(server);
rc = wait_event_killable(server->request_q,
has_credits(server, credits));
cifs_num_waiters_dec(server);
if (rc)
return rc;
spin_lock(&server->req_lock);
} else {
if (server->tcpStatus == CifsExiting) {
spin_unlock(&server->req_lock);
return -ENOENT;
}
/*
* Can not count locking commands against total
* as they are allowed to block on server.
*/
/* update # of requests on the wire to server */
if (timeout != CIFS_BLOCKING_OP) {
*credits -= 1;
server->in_flight++;
}
spin_unlock(&server->req_lock);
break;
}
}
return 0;
}
static int
wait_for_free_request(struct TCP_Server_Info *server, const int timeout,
const int optype)
{
int *val;
val = server->ops->get_credits_field(server, optype);
/* Since an echo is already inflight, no need to wait to send another */
if (*val <= 0 && optype == CIFS_ECHO_OP)
return -EAGAIN;
return wait_for_free_credits(server, timeout, val);
}
int
cifs_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
unsigned int *num, unsigned int *credits)
{
*num = size;
*credits = 0;
return 0;
}
static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,
struct mid_q_entry **ppmidQ)
{
if (ses->server->tcpStatus == CifsExiting) {
return -ENOENT;
}
if (ses->server->tcpStatus == CifsNeedReconnect) {
cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
return -EAGAIN;
}
if (ses->status == CifsNew) {
if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
(in_buf->Command != SMB_COM_NEGOTIATE))
return -EAGAIN;
/* else ok - we are setting up session */
}
if (ses->status == CifsExiting) {
/* check if SMB session is bad because we are setting it up */
if (in_buf->Command != SMB_COM_LOGOFF_ANDX)
return -EAGAIN;
/* else ok - we are shutting down session */
}
*ppmidQ = AllocMidQEntry(in_buf, ses->server);
if (*ppmidQ == NULL)
return -ENOMEM;
spin_lock(&GlobalMid_Lock);
list_add_tail(&(*ppmidQ)->qhead, &ses->server->pending_mid_q);
spin_unlock(&GlobalMid_Lock);
return 0;
}
static int
wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *midQ)
{
int error;
error = wait_event_freezekillable_unsafe(server->response_q,
midQ->mid_state != MID_REQUEST_SUBMITTED);
if (error < 0)
return -ERESTARTSYS;
return 0;
}
struct mid_q_entry *
cifs_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
{
int rc;
struct smb_hdr *hdr = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
struct mid_q_entry *mid;
/* enable signing if server requires it */
if (server->sign)
hdr->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
mid = AllocMidQEntry(hdr, server);
if (mid == NULL)
return ERR_PTR(-ENOMEM);
rc = cifs_sign_rqst(rqst, server, &mid->sequence_number);
if (rc) {
DeleteMidQEntry(mid);
return ERR_PTR(rc);
}
return mid;
}
/*
* Send a SMB request and set the callback function in the mid to handle
* the result. Caller is responsible for dealing with timeouts.
*/
int
cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
mid_receive_t *receive, mid_callback_t *callback,
void *cbdata, const int flags)
{
int rc, timeout, optype;
struct mid_q_entry *mid;
unsigned int credits = 0;
timeout = flags & CIFS_TIMEOUT_MASK;
optype = flags & CIFS_OP_MASK;
if ((flags & CIFS_HAS_CREDITS) == 0) {
rc = wait_for_free_request(server, timeout, optype);
if (rc)
return rc;
credits = 1;
}
mutex_lock(&server->srv_mutex);
mid = server->ops->setup_async_request(server, rqst);
if (IS_ERR(mid)) {
mutex_unlock(&server->srv_mutex);
add_credits_and_wake_if(server, credits, optype);
return PTR_ERR(mid);
}
mid->receive = receive;
mid->callback = callback;
mid->callback_data = cbdata;
mid->mid_state = MID_REQUEST_SUBMITTED;
/* put it on the pending_mid_q */
spin_lock(&GlobalMid_Lock);
list_add_tail(&mid->qhead, &server->pending_mid_q);
spin_unlock(&GlobalMid_Lock);
cifs_in_send_inc(server);
rc = smb_send_rqst(server, rqst);
cifs_in_send_dec(server);
cifs_save_when_sent(mid);
if (rc < 0)
server->sequence_number -= 2;
mutex_unlock(&server->srv_mutex);
if (rc == 0)
return 0;
cifs_delete_mid(mid);
add_credits_and_wake_if(server, credits, optype);
return rc;
}
/*
*
* Send an SMB Request. No response info (other than return code)
* needs to be parsed.
*
* flags indicate the type of request buffer and how long to wait
* and whether to log NT STATUS code (error) before mapping it to POSIX error
*
*/
int
SendReceiveNoRsp(const unsigned int xid, struct cifs_ses *ses,
char *in_buf, int flags)
{
int rc;
struct kvec iov[1];
int resp_buf_type;
iov[0].iov_base = in_buf;
iov[0].iov_len = get_rfc1002_length(in_buf) + 4;
flags |= CIFS_NO_RESP;
rc = SendReceive2(xid, ses, iov, 1, &resp_buf_type, flags);
cifs_dbg(NOISY, "SendRcvNoRsp flags %d rc %d\n", flags, rc);
return rc;
}
static int
cifs_sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
{
int rc = 0;
cifs_dbg(FYI, "%s: cmd=%d mid=%llu state=%d\n",
__func__, le16_to_cpu(mid->command), mid->mid, mid->mid_state);
spin_lock(&GlobalMid_Lock);
switch (mid->mid_state) {
case MID_RESPONSE_RECEIVED:
spin_unlock(&GlobalMid_Lock);
return rc;
case MID_RETRY_NEEDED:
rc = -EAGAIN;
break;
case MID_RESPONSE_MALFORMED:
rc = -EIO;
break;
case MID_SHUTDOWN:
rc = -EHOSTDOWN;
break;
default:
list_del_init(&mid->qhead);
cifs_dbg(VFS, "%s: invalid mid state mid=%llu state=%d\n",
__func__, mid->mid, mid->mid_state);
rc = -EIO;
}
spin_unlock(&GlobalMid_Lock);
DeleteMidQEntry(mid);
return rc;
}
static inline int
send_cancel(struct TCP_Server_Info *server, void *buf, struct mid_q_entry *mid)
{
return server->ops->send_cancel ?
server->ops->send_cancel(server, buf, mid) : 0;
}
int
cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
bool log_error)
{
unsigned int len = get_rfc1002_length(mid->resp_buf) + 4;
dump_smb(mid->resp_buf, min_t(u32, 92, len));
/* convert the length into a more usable form */
if (server->sign) {
struct kvec iov;
int rc = 0;
struct smb_rqst rqst = { .rq_iov = &iov,
.rq_nvec = 1 };
iov.iov_base = mid->resp_buf;
iov.iov_len = len;
/* FIXME: add code to kill session */
rc = cifs_verify_signature(&rqst, server,
mid->sequence_number);
if (rc)
cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
rc);
}
/* BB special case reconnect tid and uid here? */
return map_smb_to_linux_error(mid->resp_buf, log_error);
}
struct mid_q_entry *
cifs_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
{
int rc;
struct smb_hdr *hdr = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
struct mid_q_entry *mid;
rc = allocate_mid(ses, hdr, &mid);
if (rc)
return ERR_PTR(rc);
rc = cifs_sign_rqst(rqst, ses->server, &mid->sequence_number);
if (rc) {
cifs_delete_mid(mid);
return ERR_PTR(rc);
}
return mid;
}
int
SendReceive2(const unsigned int xid, struct cifs_ses *ses,
struct kvec *iov, int n_vec, int *resp_buf_type /* ret */,
const int flags)
{
int rc = 0;
int timeout, optype;
struct mid_q_entry *midQ;
char *buf = iov[0].iov_base;
unsigned int credits = 1;
struct smb_rqst rqst = { .rq_iov = iov,
.rq_nvec = n_vec };
timeout = flags & CIFS_TIMEOUT_MASK;
optype = flags & CIFS_OP_MASK;
*resp_buf_type = CIFS_NO_BUFFER; /* no response buf yet */
if ((ses == NULL) || (ses->server == NULL)) {
cifs_small_buf_release(buf);
cifs_dbg(VFS, "Null session\n");
return -EIO;
}
if (ses->server->tcpStatus == CifsExiting) {
cifs_small_buf_release(buf);
return -ENOENT;
}
/*
* Ensure that we do not send more than 50 overlapping requests
* to the same server. We may make this configurable later or
* use ses->maxReq.
*/
rc = wait_for_free_request(ses->server, timeout, optype);
if (rc) {
cifs_small_buf_release(buf);
return rc;
}
/*
* Make sure that we sign in the same order that we send on this socket
* and avoid races inside tcp sendmsg code that could cause corruption
* of smb data.
*/
mutex_lock(&ses->server->srv_mutex);
midQ = ses->server->ops->setup_request(ses, &rqst);
if (IS_ERR(midQ)) {
mutex_unlock(&ses->server->srv_mutex);
cifs_small_buf_release(buf);
/* Update # of requests on wire to server */
add_credits(ses->server, 1, optype);
return PTR_ERR(midQ);
}
midQ->mid_state = MID_REQUEST_SUBMITTED;
cifs_in_send_inc(ses->server);
rc = smb_sendv(ses->server, iov, n_vec);
cifs_in_send_dec(ses->server);
cifs_save_when_sent(midQ);
if (rc < 0)
ses->server->sequence_number -= 2;
mutex_unlock(&ses->server->srv_mutex);
if (rc < 0) {
cifs_small_buf_release(buf);
goto out;
}
if (timeout == CIFS_ASYNC_OP) {
cifs_small_buf_release(buf);
goto out;
}
rc = wait_for_response(ses->server, midQ);
if (rc != 0) {
send_cancel(ses->server, buf, midQ);
spin_lock(&GlobalMid_Lock);
if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
midQ->callback = DeleteMidQEntry;
spin_unlock(&GlobalMid_Lock);
cifs_small_buf_release(buf);
add_credits(ses->server, 1, optype);
return rc;
}
spin_unlock(&GlobalMid_Lock);
}
cifs_small_buf_release(buf);
rc = cifs_sync_mid_result(midQ, ses->server);
if (rc != 0) {
add_credits(ses->server, 1, optype);
return rc;
}
if (!midQ->resp_buf || midQ->mid_state != MID_RESPONSE_RECEIVED) {
rc = -EIO;
cifs_dbg(FYI, "Bad MID state?\n");
goto out;
}
buf = (char *)midQ->resp_buf;
iov[0].iov_base = buf;
iov[0].iov_len = get_rfc1002_length(buf) + 4;
if (midQ->large_buf)
*resp_buf_type = CIFS_LARGE_BUFFER;
else
*resp_buf_type = CIFS_SMALL_BUFFER;
credits = ses->server->ops->get_credits(midQ);
rc = ses->server->ops->check_receive(midQ, ses->server,
flags & CIFS_LOG_ERROR);
/* mark it so buf will not be freed by cifs_delete_mid */
if ((flags & CIFS_NO_RESP) == 0)
midQ->resp_buf = NULL;
out:
cifs_delete_mid(midQ);
add_credits(ses->server, credits, optype);
return rc;
}
int
SendReceive(const unsigned int xid, struct cifs_ses *ses,
struct smb_hdr *in_buf, struct smb_hdr *out_buf,
int *pbytes_returned, const int timeout)
{
int rc = 0;
struct mid_q_entry *midQ;
if (ses == NULL) {
cifs_dbg(VFS, "Null smb session\n");
return -EIO;
}
if (ses->server == NULL) {
cifs_dbg(VFS, "Null tcp session\n");
return -EIO;
}
if (ses->server->tcpStatus == CifsExiting)
return -ENOENT;
/* Ensure that we do not send more than 50 overlapping requests
to the same server. We may make this configurable later or
use ses->maxReq */
if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
MAX_CIFS_HDR_SIZE - 4) {
cifs_dbg(VFS, "Illegal length, greater than maximum frame, %d\n",
be32_to_cpu(in_buf->smb_buf_length));
return -EIO;
}
rc = wait_for_free_request(ses->server, timeout, 0);
if (rc)
return rc;
/* make sure that we sign in the same order that we send on this socket
and avoid races inside tcp sendmsg code that could cause corruption
of smb data */
mutex_lock(&ses->server->srv_mutex);
rc = allocate_mid(ses, in_buf, &midQ);
if (rc) {
mutex_unlock(&ses->server->srv_mutex);
/* Update # of requests on wire to server */
add_credits(ses->server, 1, 0);
return rc;
}
rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
if (rc) {
mutex_unlock(&ses->server->srv_mutex);
goto out;
}
midQ->mid_state = MID_REQUEST_SUBMITTED;
cifs_in_send_inc(ses->server);
rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
cifs_in_send_dec(ses->server);
cifs_save_when_sent(midQ);
if (rc < 0)
ses->server->sequence_number -= 2;
mutex_unlock(&ses->server->srv_mutex);
if (rc < 0)
goto out;
if (timeout == CIFS_ASYNC_OP)
goto out;
rc = wait_for_response(ses->server, midQ);
if (rc != 0) {
send_cancel(ses->server, in_buf, midQ);
spin_lock(&GlobalMid_Lock);
if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
/* no longer considered to be "in-flight" */
midQ->callback = DeleteMidQEntry;
spin_unlock(&GlobalMid_Lock);
add_credits(ses->server, 1, 0);
return rc;
}
spin_unlock(&GlobalMid_Lock);
}
rc = cifs_sync_mid_result(midQ, ses->server);
if (rc != 0) {
add_credits(ses->server, 1, 0);
return rc;
}
if (!midQ->resp_buf || !out_buf ||
midQ->mid_state != MID_RESPONSE_RECEIVED) {
rc = -EIO;
cifs_dbg(VFS, "Bad MID state?\n");
goto out;
}
*pbytes_returned = get_rfc1002_length(midQ->resp_buf);
memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
rc = cifs_check_receive(midQ, ses->server, 0);
out:
cifs_delete_mid(midQ);
add_credits(ses->server, 1, 0);
return rc;
}
/* We send a LOCKINGX_CANCEL_LOCK to cause the Windows
blocking lock to return. */
static int
send_lock_cancel(const unsigned int xid, struct cifs_tcon *tcon,
struct smb_hdr *in_buf,
struct smb_hdr *out_buf)
{
int bytes_returned;
struct cifs_ses *ses = tcon->ses;
LOCK_REQ *pSMB = (LOCK_REQ *)in_buf;
/* We just modify the current in_buf to change
the type of lock from LOCKING_ANDX_SHARED_LOCK
or LOCKING_ANDX_EXCLUSIVE_LOCK to
LOCKING_ANDX_CANCEL_LOCK. */
pSMB->LockType = LOCKING_ANDX_CANCEL_LOCK|LOCKING_ANDX_LARGE_FILES;
pSMB->Timeout = 0;
pSMB->hdr.Mid = get_next_mid(ses->server);
return SendReceive(xid, ses, in_buf, out_buf,
&bytes_returned, 0);
}
int
SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
struct smb_hdr *in_buf, struct smb_hdr *out_buf,
int *pbytes_returned)
{
int rc = 0;
int rstart = 0;
struct mid_q_entry *midQ;
struct cifs_ses *ses;
if (tcon == NULL || tcon->ses == NULL) {
cifs_dbg(VFS, "Null smb session\n");
return -EIO;
}
ses = tcon->ses;
if (ses->server == NULL) {
cifs_dbg(VFS, "Null tcp session\n");
return -EIO;
}
if (ses->server->tcpStatus == CifsExiting)
return -ENOENT;
/* Ensure that we do not send more than 50 overlapping requests
to the same server. We may make this configurable later or
use ses->maxReq */
if (be32_to_cpu(in_buf->smb_buf_length) > CIFSMaxBufSize +
MAX_CIFS_HDR_SIZE - 4) {
cifs_dbg(VFS, "Illegal length, greater than maximum frame, %d\n",
be32_to_cpu(in_buf->smb_buf_length));
return -EIO;
}
rc = wait_for_free_request(ses->server, CIFS_BLOCKING_OP, 0);
if (rc)
return rc;
/* make sure that we sign in the same order that we send on this socket
and avoid races inside tcp sendmsg code that could cause corruption
of smb data */
mutex_lock(&ses->server->srv_mutex);
rc = allocate_mid(ses, in_buf, &midQ);
if (rc) {
mutex_unlock(&ses->server->srv_mutex);
return rc;
}
rc = cifs_sign_smb(in_buf, ses->server, &midQ->sequence_number);
if (rc) {
cifs_delete_mid(midQ);
mutex_unlock(&ses->server->srv_mutex);
return rc;
}
midQ->mid_state = MID_REQUEST_SUBMITTED;
cifs_in_send_inc(ses->server);
rc = smb_send(ses->server, in_buf, be32_to_cpu(in_buf->smb_buf_length));
cifs_in_send_dec(ses->server);
cifs_save_when_sent(midQ);
if (rc < 0)
ses->server->sequence_number -= 2;
mutex_unlock(&ses->server->srv_mutex);
if (rc < 0) {
cifs_delete_mid(midQ);
return rc;
}
/* Wait for a reply - allow signals to interrupt. */
rc = wait_event_interruptible(ses->server->response_q,
(!(midQ->mid_state == MID_REQUEST_SUBMITTED)) ||
((ses->server->tcpStatus != CifsGood) &&
(ses->server->tcpStatus != CifsNew)));
/* Were we interrupted by a signal ? */
if ((rc == -ERESTARTSYS) &&
(midQ->mid_state == MID_REQUEST_SUBMITTED) &&
((ses->server->tcpStatus == CifsGood) ||
(ses->server->tcpStatus == CifsNew))) {
if (in_buf->Command == SMB_COM_TRANSACTION2) {
/* POSIX lock. We send a NT_CANCEL SMB to cause the
blocking lock to return. */
rc = send_cancel(ses->server, in_buf, midQ);
if (rc) {
cifs_delete_mid(midQ);
return rc;
}
} else {
/* Windows lock. We send a LOCKINGX_CANCEL_LOCK
to cause the blocking lock to return. */
rc = send_lock_cancel(xid, tcon, in_buf, out_buf);
/* If we get -ENOLCK back the lock may have
already been removed. Don't exit in this case. */
if (rc && rc != -ENOLCK) {
cifs_delete_mid(midQ);
return rc;
}
}
rc = wait_for_response(ses->server, midQ);
if (rc) {
send_cancel(ses->server, in_buf, midQ);
spin_lock(&GlobalMid_Lock);
if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
/* no longer considered to be "in-flight" */
midQ->callback = DeleteMidQEntry;
spin_unlock(&GlobalMid_Lock);
return rc;
}
spin_unlock(&GlobalMid_Lock);
}
/* We got the response - restart system call. */
rstart = 1;
}
rc = cifs_sync_mid_result(midQ, ses->server);
if (rc != 0)
return rc;
/* rcvd frame is ok */
if (out_buf == NULL || midQ->mid_state != MID_RESPONSE_RECEIVED) {
rc = -EIO;
cifs_dbg(VFS, "Bad MID state?\n");
goto out;
}
*pbytes_returned = get_rfc1002_length(midQ->resp_buf);
memcpy(out_buf, midQ->resp_buf, *pbytes_returned + 4);
rc = cifs_check_receive(midQ, ses->server, 0);
out:
cifs_delete_mid(midQ);
if (rstart && rc == -EACCES)
return -ERESTARTSYS;
return rc;
}