/* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #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)) { pr_debug(" CIFS slow rsp: cmd %d mid %llu", midEntry->command, midEntry->mid); pr_info(" 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 * @smb_msg: Message to send * @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 msghdr *smb_msg, size_t *sent) { int rc = 0; int retries = 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; while (msg_data_left(smb_msg)) { /* * 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 = sock_sendmsg(ssocket, smb_msg); if (rc == -EAGAIN) { retries++; if (retries >= 14 || (!server->noblocksnd && (retries > 2))) { cifs_dbg(VFS, "sends on sock %p stuck for 15 seconds\n", ssocket); return -EAGAIN; } msleep(1 << retries); continue; } if (rc < 0) return rc; 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; } /* send was at least partially successful */ *sent += rc; retries = 0; /* in case we get ENOSPC on the next send */ } return 0; } 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, size; struct socket *ssocket = server->ssocket; struct msghdr smb_msg; 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; } if (n_vec < 2) return -EIO; cifs_dbg(FYI, "Sending smb: smb_len=%u\n", smb_buf_length); dump_smb(iov[0].iov_base, iov[0].iov_len); dump_smb(iov[1].iov_base, iov[1].iov_len); /* cork the socket */ kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK, (char *)&val, sizeof(val)); size = 0; for (i = 0; i < n_vec; i++) size += iov[i].iov_len; iov_iter_kvec(&smb_msg.msg_iter, WRITE | ITER_KVEC, iov, n_vec, size); rc = smb_send_kvec(server, &smb_msg, &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++) { size_t len = i == rqst->rq_npages - 1 ? rqst->rq_tailsz : rqst->rq_pagesz; struct bio_vec bvec = { .bv_page = rqst->rq_pages[i], .bv_len = len }; iov_iter_bvec(&smb_msg.msg_iter, WRITE | ITER_BVEC, &bvec, 1, len); rc = smb_send_kvec(server, &smb_msg, &sent); 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[2]; iov[0].iov_base = smb_buffer; iov[0].iov_len = 4; iov[1].iov_base = (char *)smb_buffer + 4; iov[1].iov_len = smb_buf_length; return smb_sendv(server, iov, 2); } 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; if (rqst->rq_iov[0].iov_len != 4 || rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base) return ERR_PTR(-EIO); /* 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; cifs_delete_mid(mid); } mutex_unlock(&server->srv_mutex); if (rc == 0) return 0; 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]; struct kvec rsp_iov; 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, &rsp_iov); 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); mutex_lock(&server->srv_mutex); DeleteMidQEntry(mid); mutex_unlock(&server->srv_mutex); return rc; } static inline int send_cancel(struct TCP_Server_Info *server, struct smb_rqst *rqst, struct mid_q_entry *mid) { return server->ops->send_cancel ? server->ops->send_cancel(server, rqst, 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[2]; int rc = 0; struct smb_rqst rqst = { .rq_iov = iov, .rq_nvec = 2 }; iov[0].iov_base = mid->resp_buf; iov[0].iov_len = 4; iov[1].iov_base = (char *)mid->resp_buf + 4; iov[1].iov_len = len - 4; /* 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; if (rqst->rq_iov[0].iov_len != 4 || rqst->rq_iov[0].iov_base + 4 != rqst->rq_iov[1].iov_base) return ERR_PTR(-EIO); 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 cifs_send_recv(const unsigned int xid, struct cifs_ses *ses, struct smb_rqst *rqst, int *resp_buf_type, const int flags, struct kvec *resp_iov) { int rc = 0; int timeout, optype; struct mid_q_entry *midQ; unsigned int credits = 1; char *buf; 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_dbg(VFS, "Null 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. */ rc = wait_for_free_request(ses->server, timeout, optype); 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); midQ = ses->server->ops->setup_request(ses, rqst); if (IS_ERR(midQ)) { mutex_unlock(&ses->server->srv_mutex); /* 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_send_rqst(ses->server, rqst); 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, rqst, midQ); spin_lock(&GlobalMid_Lock); if (midQ->mid_state == MID_REQUEST_SUBMITTED) { midQ->callback = DeleteMidQEntry; spin_unlock(&GlobalMid_Lock); add_credits(ses->server, 1, optype); return rc; } spin_unlock(&GlobalMid_Lock); } 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; resp_iov->iov_base = buf; resp_iov->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 SendReceive2(const unsigned int xid, struct cifs_ses *ses, struct kvec *iov, int n_vec, int *resp_buf_type /* ret */, const int flags, struct kvec *resp_iov) { struct smb_rqst rqst; struct kvec *new_iov; int rc; new_iov = kmalloc(sizeof(struct kvec) * (n_vec + 1), GFP_KERNEL); if (!new_iov) return -ENOMEM; /* 1st iov is a RFC1001 length followed by the rest of the packet */ memcpy(new_iov + 1, iov, (sizeof(struct kvec) * n_vec)); new_iov[0].iov_base = new_iov[1].iov_base; new_iov[0].iov_len = 4; new_iov[1].iov_base += 4; new_iov[1].iov_len -= 4; memset(&rqst, 0, sizeof(struct smb_rqst)); rqst.rq_iov = new_iov; rqst.rq_nvec = n_vec + 1; rc = cifs_send_recv(xid, ses, &rqst, resp_buf_type, flags, resp_iov); kfree(new_iov); 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; unsigned int len = be32_to_cpu(in_buf->smb_buf_length); struct kvec iov = { .iov_base = in_buf, .iov_len = len }; struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 }; 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 (len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) { cifs_dbg(VFS, "Illegal length, greater than maximum frame, %d\n", len); 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, len); 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, &rqst, 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; unsigned int len = be32_to_cpu(in_buf->smb_buf_length); struct kvec iov = { .iov_base = in_buf, .iov_len = len }; struct smb_rqst rqst = { .rq_iov = &iov, .rq_nvec = 1 }; 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 (len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) { cifs_dbg(VFS, "Illegal length, greater than maximum frame, %d\n", len); 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, len); 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, &rqst, 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, &rqst, 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; }