diff options
Diffstat (limited to 'kernel/fs/cifs/transport.c')
| -rw-r--r-- | kernel/fs/cifs/transport.c | 1113 |
1 files changed, 1113 insertions, 0 deletions
diff --git a/kernel/fs/cifs/transport.c b/kernel/fs/cifs/transport.c new file mode 100644 index 000000000..126f46b88 --- /dev/null +++ b/kernel/fs/cifs/transport.c @@ -0,0 +1,1113 @@ +/* + * 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)) { + 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 + * @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; +} |