linux/fs/cifs/transport.c
Shyam Prasad N dca65818c8 cifs: use a different reconnect helper for non-cifsd threads
The cifs_demultiplexer_thread should only call cifs_reconnect.
If any other thread wants to trigger a reconnect, they can do
so by updating the server tcpStatus to CifsNeedReconnect.

The last patch attempted to use the same helper function for
both types of threads, but that causes other issues
with lock dependencies.

This patch creates a new helper for non-cifsd threads, that
will indicate to cifsd that the server needs reconnect.

Fixes: 2a05137a05 ("cifs: mark sessions for reconnection in helper function")
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-03-18 23:12:03 -05:00

1640 lines
43 KiB
C

// SPDX-License-Identifier: LGPL-2.1
/*
*
* Copyright (C) International Business Machines Corp., 2002,2008
* Author(s): Steve French (sfrench@us.ibm.com)
* Jeremy Allison (jra@samba.org) 2006.
*
*/
#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/bvec.h>
#include <linux/highmem.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <linux/mempool.h>
#include <linux/sched/signal.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "smb2proto.h"
#include "smbdirect.h"
/* Max number of iovectors we can use off the stack when sending requests. */
#define CIFS_MAX_IOV_SIZE 8
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);
memset(temp, 0, sizeof(struct mid_q_entry));
kref_init(&temp->refcount);
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.
*/
get_task_struct(current);
temp->creator = current;
temp->callback = cifs_wake_up_task;
temp->callback_data = current;
atomic_inc(&midCount);
temp->mid_state = MID_REQUEST_ALLOCATED;
return temp;
}
static void _cifs_mid_q_entry_release(struct kref *refcount)
{
struct mid_q_entry *midEntry =
container_of(refcount, struct mid_q_entry, refcount);
#ifdef CONFIG_CIFS_STATS2
__le16 command = midEntry->server->vals->lock_cmd;
__u16 smb_cmd = le16_to_cpu(midEntry->command);
unsigned long now;
unsigned long roundtrip_time;
#endif
struct TCP_Server_Info *server = midEntry->server;
if (midEntry->resp_buf && (midEntry->mid_flags & MID_WAIT_CANCELLED) &&
midEntry->mid_state == MID_RESPONSE_RECEIVED &&
server->ops->handle_cancelled_mid)
server->ops->handle_cancelled_mid(midEntry, server);
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;
if (now < midEntry->when_alloc)
cifs_server_dbg(VFS, "Invalid mid allocation time\n");
roundtrip_time = now - midEntry->when_alloc;
if (smb_cmd < NUMBER_OF_SMB2_COMMANDS) {
if (atomic_read(&server->num_cmds[smb_cmd]) == 0) {
server->slowest_cmd[smb_cmd] = roundtrip_time;
server->fastest_cmd[smb_cmd] = roundtrip_time;
} else {
if (server->slowest_cmd[smb_cmd] < roundtrip_time)
server->slowest_cmd[smb_cmd] = roundtrip_time;
else if (server->fastest_cmd[smb_cmd] > roundtrip_time)
server->fastest_cmd[smb_cmd] = roundtrip_time;
}
cifs_stats_inc(&server->num_cmds[smb_cmd]);
server->time_per_cmd[smb_cmd] += roundtrip_time;
}
/*
* commands taking longer than one second (default) can be indications
* that something is wrong, unless it is quite a slow link or a very
* busy server. Note that this calc is unlikely or impossible to wrap
* as long as slow_rsp_threshold is not set way above recommended max
* value (32767 ie 9 hours) and is generally harmless even if wrong
* since only affects debug counters - so leaving the calc as simple
* comparison rather than doing multiple conversions and overflow
* checks
*/
if ((slow_rsp_threshold != 0) &&
time_after(now, midEntry->when_alloc + (slow_rsp_threshold * HZ)) &&
(midEntry->command != command)) {
/*
* smb2slowcmd[NUMBER_OF_SMB2_COMMANDS] counts by command
* NB: le16_to_cpu returns unsigned so can not be negative below
*/
if (smb_cmd < NUMBER_OF_SMB2_COMMANDS)
cifs_stats_inc(&server->smb2slowcmd[smb_cmd]);
trace_smb3_slow_rsp(smb_cmd, midEntry->mid, midEntry->pid,
midEntry->when_sent, midEntry->when_received);
if (cifsFYI & CIFS_TIMER) {
pr_debug("slow rsp: cmd %d mid %llu",
midEntry->command, midEntry->mid);
cifs_info("A: 0x%lx S: 0x%lx R: 0x%lx\n",
now - midEntry->when_alloc,
now - midEntry->when_sent,
now - midEntry->when_received);
}
}
#endif
put_task_struct(midEntry->creator);
mempool_free(midEntry, cifs_mid_poolp);
}
void cifs_mid_q_entry_release(struct mid_q_entry *midEntry)
{
spin_lock(&GlobalMid_Lock);
kref_put(&midEntry->refcount, _cifs_mid_q_entry_release);
spin_unlock(&GlobalMid_Lock);
}
void DeleteMidQEntry(struct mid_q_entry *midEntry)
{
cifs_mid_q_entry_release(midEntry);
}
void
cifs_delete_mid(struct mid_q_entry *mid)
{
spin_lock(&GlobalMid_Lock);
if (!(mid->mid_flags & MID_DELETED)) {
list_del_init(&mid->qhead);
mid->mid_flags |= MID_DELETED;
}
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_server_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_server_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;
}
unsigned long
smb_rqst_len(struct TCP_Server_Info *server, struct smb_rqst *rqst)
{
unsigned int i;
struct kvec *iov;
int nvec;
unsigned long buflen = 0;
if (server->vals->header_preamble_size == 0 &&
rqst->rq_nvec >= 2 && rqst->rq_iov[0].iov_len == 4) {
iov = &rqst->rq_iov[1];
nvec = rqst->rq_nvec - 1;
} else {
iov = rqst->rq_iov;
nvec = rqst->rq_nvec;
}
/* total up iov array first */
for (i = 0; i < nvec; i++)
buflen += iov[i].iov_len;
/*
* Add in the page array if there is one. The caller needs to make
* sure rq_offset and rq_tailsz are set correctly. If a buffer of
* multiple pages ends at page boundary, rq_tailsz needs to be set to
* PAGE_SIZE.
*/
if (rqst->rq_npages) {
if (rqst->rq_npages == 1)
buflen += rqst->rq_tailsz;
else {
/*
* If there is more than one page, calculate the
* buffer length based on rq_offset and rq_tailsz
*/
buflen += rqst->rq_pagesz * (rqst->rq_npages - 1) -
rqst->rq_offset;
buflen += rqst->rq_tailsz;
}
}
return buflen;
}
static int
__smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
struct smb_rqst *rqst)
{
int rc = 0;
struct kvec *iov;
int n_vec;
unsigned int send_length = 0;
unsigned int i, j;
sigset_t mask, oldmask;
size_t total_len = 0, sent, size;
struct socket *ssocket = server->ssocket;
struct msghdr smb_msg;
__be32 rfc1002_marker;
if (cifs_rdma_enabled(server)) {
/* return -EAGAIN when connecting or reconnecting */
rc = -EAGAIN;
if (server->smbd_conn)
rc = smbd_send(server, num_rqst, rqst);
goto smbd_done;
}
if (ssocket == NULL)
return -EAGAIN;
if (fatal_signal_pending(current)) {
cifs_dbg(FYI, "signal pending before send request\n");
return -ERESTARTSYS;
}
/* cork the socket */
tcp_sock_set_cork(ssocket->sk, true);
for (j = 0; j < num_rqst; j++)
send_length += smb_rqst_len(server, &rqst[j]);
rfc1002_marker = cpu_to_be32(send_length);
/*
* We should not allow signals to interrupt the network send because
* any partial send will cause session reconnects thus increasing
* latency of system calls and overload a server with unnecessary
* requests.
*/
sigfillset(&mask);
sigprocmask(SIG_BLOCK, &mask, &oldmask);
/* Generate a rfc1002 marker for SMB2+ */
if (server->vals->header_preamble_size == 0) {
struct kvec hiov = {
.iov_base = &rfc1002_marker,
.iov_len = 4
};
iov_iter_kvec(&smb_msg.msg_iter, WRITE, &hiov, 1, 4);
rc = smb_send_kvec(server, &smb_msg, &sent);
if (rc < 0)
goto unmask;
total_len += sent;
send_length += 4;
}
cifs_dbg(FYI, "Sending smb: smb_len=%u\n", send_length);
for (j = 0; j < num_rqst; j++) {
iov = rqst[j].rq_iov;
n_vec = rqst[j].rq_nvec;
size = 0;
for (i = 0; i < n_vec; i++) {
dump_smb(iov[i].iov_base, iov[i].iov_len);
size += iov[i].iov_len;
}
iov_iter_kvec(&smb_msg.msg_iter, WRITE, iov, n_vec, size);
rc = smb_send_kvec(server, &smb_msg, &sent);
if (rc < 0)
goto unmask;
total_len += sent;
/* now walk the page array and send each page in it */
for (i = 0; i < rqst[j].rq_npages; i++) {
struct bio_vec bvec;
bvec.bv_page = rqst[j].rq_pages[i];
rqst_page_get_length(&rqst[j], i, &bvec.bv_len,
&bvec.bv_offset);
iov_iter_bvec(&smb_msg.msg_iter, WRITE,
&bvec, 1, bvec.bv_len);
rc = smb_send_kvec(server, &smb_msg, &sent);
if (rc < 0)
break;
total_len += sent;
}
}
unmask:
sigprocmask(SIG_SETMASK, &oldmask, NULL);
/*
* If signal is pending but we have already sent the whole packet to
* the server we need to return success status to allow a corresponding
* mid entry to be kept in the pending requests queue thus allowing
* to handle responses from the server by the client.
*
* If only part of the packet has been sent there is no need to hide
* interrupt because the session will be reconnected anyway, so there
* won't be any response from the server to handle.
*/
if (signal_pending(current) && (total_len != send_length)) {
cifs_dbg(FYI, "signal is pending after attempt to send\n");
rc = -ERESTARTSYS;
}
/* uncork it */
tcp_sock_set_cork(ssocket->sk, false);
if ((total_len > 0) && (total_len != send_length)) {
cifs_dbg(FYI, "partial send (wanted=%u sent=%zu): terminating session\n",
send_length, 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
*/
cifs_signal_cifsd_for_reconnect(server, false);
trace_smb3_partial_send_reconnect(server->CurrentMid,
server->conn_id, server->hostname);
}
smbd_done:
if (rc < 0 && rc != -EINTR)
cifs_server_dbg(VFS, "Error %d sending data on socket to server\n",
rc);
else if (rc > 0)
rc = 0;
return rc;
}
static int
smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
struct smb_rqst *rqst, int flags)
{
struct kvec iov;
struct smb2_transform_hdr *tr_hdr;
struct smb_rqst cur_rqst[MAX_COMPOUND];
int rc;
if (!(flags & CIFS_TRANSFORM_REQ))
return __smb_send_rqst(server, num_rqst, rqst);
if (num_rqst > MAX_COMPOUND - 1)
return -ENOMEM;
if (!server->ops->init_transform_rq) {
cifs_server_dbg(VFS, "Encryption requested but transform callback is missing\n");
return -EIO;
}
tr_hdr = kmalloc(sizeof(*tr_hdr), GFP_NOFS);
if (!tr_hdr)
return -ENOMEM;
memset(&cur_rqst[0], 0, sizeof(cur_rqst));
memset(&iov, 0, sizeof(iov));
memset(tr_hdr, 0, sizeof(*tr_hdr));
iov.iov_base = tr_hdr;
iov.iov_len = sizeof(*tr_hdr);
cur_rqst[0].rq_iov = &iov;
cur_rqst[0].rq_nvec = 1;
rc = server->ops->init_transform_rq(server, num_rqst + 1,
&cur_rqst[0], rqst);
if (rc)
goto out;
rc = __smb_send_rqst(server, num_rqst + 1, &cur_rqst[0]);
smb3_free_compound_rqst(num_rqst, &cur_rqst[1]);
out:
kfree(tr_hdr);
return rc;
}
int
smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
unsigned int smb_buf_length)
{
struct kvec iov[2];
struct smb_rqst rqst = { .rq_iov = iov,
.rq_nvec = 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_send_rqst(server, 1, &rqst);
}
static int
wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
const int timeout, const int flags,
unsigned int *instance)
{
long rc;
int *credits;
int optype;
long int t;
int scredits, in_flight;
if (timeout < 0)
t = MAX_JIFFY_OFFSET;
else
t = msecs_to_jiffies(timeout);
optype = flags & CIFS_OP_MASK;
*instance = 0;
credits = server->ops->get_credits_field(server, optype);
/* Since an echo is already inflight, no need to wait to send another */
if (*credits <= 0 && optype == CIFS_ECHO_OP)
return -EAGAIN;
spin_lock(&server->req_lock);
if ((flags & CIFS_TIMEOUT_MASK) == CIFS_NON_BLOCKING) {
/* oplock breaks must not be held up */
server->in_flight++;
if (server->in_flight > server->max_in_flight)
server->max_in_flight = server->in_flight;
*credits -= 1;
*instance = server->reconnect_instance;
scredits = *credits;
in_flight = server->in_flight;
spin_unlock(&server->req_lock);
trace_smb3_add_credits(server->CurrentMid,
server->conn_id, server->hostname, scredits, -1, in_flight);
cifs_dbg(FYI, "%s: remove %u credits total=%d\n",
__func__, 1, scredits);
return 0;
}
while (1) {
if (*credits < num_credits) {
scredits = *credits;
spin_unlock(&server->req_lock);
cifs_num_waiters_inc(server);
rc = wait_event_killable_timeout(server->request_q,
has_credits(server, credits, num_credits), t);
cifs_num_waiters_dec(server);
if (!rc) {
spin_lock(&server->req_lock);
scredits = *credits;
in_flight = server->in_flight;
spin_unlock(&server->req_lock);
trace_smb3_credit_timeout(server->CurrentMid,
server->conn_id, server->hostname, scredits,
num_credits, in_flight);
cifs_server_dbg(VFS, "wait timed out after %d ms\n",
timeout);
return -EBUSY;
}
if (rc == -ERESTARTSYS)
return -ERESTARTSYS;
spin_lock(&server->req_lock);
} else {
spin_unlock(&server->req_lock);
spin_lock(&cifs_tcp_ses_lock);
if (server->tcpStatus == CifsExiting) {
spin_unlock(&cifs_tcp_ses_lock);
return -ENOENT;
}
spin_unlock(&cifs_tcp_ses_lock);
/*
* For normal commands, reserve the last MAX_COMPOUND
* credits to compound requests.
* Otherwise these compounds could be permanently
* starved for credits by single-credit requests.
*
* To prevent spinning CPU, block this thread until
* there are >MAX_COMPOUND credits available.
* But only do this is we already have a lot of
* credits in flight to avoid triggering this check
* for servers that are slow to hand out credits on
* new sessions.
*/
spin_lock(&server->req_lock);
if (!optype && num_credits == 1 &&
server->in_flight > 2 * MAX_COMPOUND &&
*credits <= MAX_COMPOUND) {
spin_unlock(&server->req_lock);
cifs_num_waiters_inc(server);
rc = wait_event_killable_timeout(
server->request_q,
has_credits(server, credits,
MAX_COMPOUND + 1),
t);
cifs_num_waiters_dec(server);
if (!rc) {
spin_lock(&server->req_lock);
scredits = *credits;
in_flight = server->in_flight;
spin_unlock(&server->req_lock);
trace_smb3_credit_timeout(
server->CurrentMid,
server->conn_id, server->hostname,
scredits, num_credits, in_flight);
cifs_server_dbg(VFS, "wait timed out after %d ms\n",
timeout);
return -EBUSY;
}
if (rc == -ERESTARTSYS)
return -ERESTARTSYS;
spin_lock(&server->req_lock);
continue;
}
/*
* Can not count locking commands against total
* as they are allowed to block on server.
*/
/* update # of requests on the wire to server */
if ((flags & CIFS_TIMEOUT_MASK) != CIFS_BLOCKING_OP) {
*credits -= num_credits;
server->in_flight += num_credits;
if (server->in_flight > server->max_in_flight)
server->max_in_flight = server->in_flight;
*instance = server->reconnect_instance;
}
scredits = *credits;
in_flight = server->in_flight;
spin_unlock(&server->req_lock);
trace_smb3_add_credits(server->CurrentMid,
server->conn_id, server->hostname, scredits,
-(num_credits), in_flight);
cifs_dbg(FYI, "%s: remove %u credits total=%d\n",
__func__, num_credits, scredits);
break;
}
}
return 0;
}
static int
wait_for_free_request(struct TCP_Server_Info *server, const int flags,
unsigned int *instance)
{
return wait_for_free_credits(server, 1, -1, flags,
instance);
}
static int
wait_for_compound_request(struct TCP_Server_Info *server, int num,
const int flags, unsigned int *instance)
{
int *credits;
int scredits, in_flight;
credits = server->ops->get_credits_field(server, flags & CIFS_OP_MASK);
spin_lock(&server->req_lock);
scredits = *credits;
in_flight = server->in_flight;
if (*credits < num) {
/*
* If the server is tight on resources or just gives us less
* credits for other reasons (e.g. requests are coming out of
* order and the server delays granting more credits until it
* processes a missing mid) and we exhausted most available
* credits there may be situations when we try to send
* a compound request but we don't have enough credits. At this
* point the client needs to decide if it should wait for
* additional credits or fail the request. If at least one
* request is in flight there is a high probability that the
* server will return enough credits to satisfy this compound
* request.
*
* Return immediately if no requests in flight since we will be
* stuck on waiting for credits.
*/
if (server->in_flight == 0) {
spin_unlock(&server->req_lock);
trace_smb3_insufficient_credits(server->CurrentMid,
server->conn_id, server->hostname, scredits,
num, in_flight);
cifs_dbg(FYI, "%s: %d requests in flight, needed %d total=%d\n",
__func__, in_flight, num, scredits);
return -EDEADLK;
}
}
spin_unlock(&server->req_lock);
return wait_for_free_credits(server, num, 60000, flags,
instance);
}
int
cifs_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
unsigned int *num, struct cifs_credits *credits)
{
*num = size;
credits->value = 0;
credits->instance = server->reconnect_instance;
return 0;
}
static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,
struct mid_q_entry **ppmidQ)
{
spin_lock(&cifs_tcp_ses_lock);
if (ses->status == CifsNew) {
if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
(in_buf->Command != SMB_COM_NEGOTIATE)) {
spin_unlock(&cifs_tcp_ses_lock);
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) {
spin_unlock(&cifs_tcp_ses_lock);
return -EAGAIN;
}
/* else ok - we are shutting down session */
}
spin_unlock(&cifs_tcp_ses_lock);
*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,
mid_handle_t *handle, void *cbdata, const int flags,
const struct cifs_credits *exist_credits)
{
int rc;
struct mid_q_entry *mid;
struct cifs_credits credits = { .value = 0, .instance = 0 };
unsigned int instance;
int optype;
optype = flags & CIFS_OP_MASK;
if ((flags & CIFS_HAS_CREDITS) == 0) {
rc = wait_for_free_request(server, flags, &instance);
if (rc)
return rc;
credits.value = 1;
credits.instance = instance;
} else
instance = exist_credits->instance;
mutex_lock(&server->srv_mutex);
/*
* We can't use credits obtained from the previous session to send this
* request. Check if there were reconnects after we obtained credits and
* return -EAGAIN in such cases to let callers handle it.
*/
if (instance != server->reconnect_instance) {
mutex_unlock(&server->srv_mutex);
add_credits_and_wake_if(server, &credits, optype);
return -EAGAIN;
}
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->handle = handle;
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);
/*
* Need to store the time in mid before calling I/O. For call_async,
* I/O response may come back and free the mid entry on another thread.
*/
cifs_save_when_sent(mid);
cifs_in_send_inc(server);
rc = smb_send_rqst(server, 1, rqst, flags);
cifs_in_send_dec(server);
if (rc < 0) {
revert_current_mid(server, mid->credits);
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_RSP_BUF;
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:
if (!(mid->mid_flags & MID_DELETED)) {
list_del_init(&mid->qhead);
mid->mid_flags |= MID_DELETED;
}
cifs_server_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, 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_server_dbg(VFS, "SMB signature verification returned error = %d\n",
rc);
}
/* BB special case reconnect tid and uid here? */
return map_and_check_smb_error(mid, log_error);
}
struct mid_q_entry *
cifs_setup_request(struct cifs_ses *ses, struct TCP_Server_Info *ignored,
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;
}
static void
cifs_compound_callback(struct mid_q_entry *mid)
{
struct TCP_Server_Info *server = mid->server;
struct cifs_credits credits;
credits.value = server->ops->get_credits(mid);
credits.instance = server->reconnect_instance;
add_credits(server, &credits, mid->optype);
}
static void
cifs_compound_last_callback(struct mid_q_entry *mid)
{
cifs_compound_callback(mid);
cifs_wake_up_task(mid);
}
static void
cifs_cancelled_callback(struct mid_q_entry *mid)
{
cifs_compound_callback(mid);
DeleteMidQEntry(mid);
}
/*
* Return a channel (master if none) of @ses that can be used to send
* regular requests.
*
* If we are currently binding a new channel (negprot/sess.setup),
* return the new incomplete channel.
*/
struct TCP_Server_Info *cifs_pick_channel(struct cifs_ses *ses)
{
uint index = 0;
if (!ses)
return NULL;
/* round robin */
index = (uint)atomic_inc_return(&ses->chan_seq);
spin_lock(&ses->chan_lock);
index %= ses->chan_count;
spin_unlock(&ses->chan_lock);
return ses->chans[index].server;
}
int
compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
struct TCP_Server_Info *server,
const int flags, const int num_rqst, struct smb_rqst *rqst,
int *resp_buf_type, struct kvec *resp_iov)
{
int i, j, optype, rc = 0;
struct mid_q_entry *midQ[MAX_COMPOUND];
bool cancelled_mid[MAX_COMPOUND] = {false};
struct cifs_credits credits[MAX_COMPOUND] = {
{ .value = 0, .instance = 0 }
};
unsigned int instance;
char *buf;
optype = flags & CIFS_OP_MASK;
for (i = 0; i < num_rqst; i++)
resp_buf_type[i] = CIFS_NO_BUFFER; /* no response buf yet */
if (!ses || !ses->server || !server) {
cifs_dbg(VFS, "Null session\n");
return -EIO;
}
spin_lock(&cifs_tcp_ses_lock);
if (server->tcpStatus == CifsExiting) {
spin_unlock(&cifs_tcp_ses_lock);
return -ENOENT;
}
spin_unlock(&cifs_tcp_ses_lock);
/*
* Wait for all the requests to become available.
* This approach still leaves the possibility to be stuck waiting for
* credits if the server doesn't grant credits to the outstanding
* requests and if the client is completely idle, not generating any
* other requests.
* This can be handled by the eventual session reconnect.
*/
rc = wait_for_compound_request(server, num_rqst, flags,
&instance);
if (rc)
return rc;
for (i = 0; i < num_rqst; i++) {
credits[i].value = 1;
credits[i].instance = instance;
}
/*
* 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(&server->srv_mutex);
/*
* All the parts of the compound chain belong obtained credits from the
* same session. We can not use credits obtained from the previous
* session to send this request. Check if there were reconnects after
* we obtained credits and return -EAGAIN in such cases to let callers
* handle it.
*/
if (instance != server->reconnect_instance) {
mutex_unlock(&server->srv_mutex);
for (j = 0; j < num_rqst; j++)
add_credits(server, &credits[j], optype);
return -EAGAIN;
}
for (i = 0; i < num_rqst; i++) {
midQ[i] = server->ops->setup_request(ses, server, &rqst[i]);
if (IS_ERR(midQ[i])) {
revert_current_mid(server, i);
for (j = 0; j < i; j++)
cifs_delete_mid(midQ[j]);
mutex_unlock(&server->srv_mutex);
/* Update # of requests on wire to server */
for (j = 0; j < num_rqst; j++)
add_credits(server, &credits[j], optype);
return PTR_ERR(midQ[i]);
}
midQ[i]->mid_state = MID_REQUEST_SUBMITTED;
midQ[i]->optype = optype;
/*
* Invoke callback for every part of the compound chain
* to calculate credits properly. Wake up this thread only when
* the last element is received.
*/
if (i < num_rqst - 1)
midQ[i]->callback = cifs_compound_callback;
else
midQ[i]->callback = cifs_compound_last_callback;
}
cifs_in_send_inc(server);
rc = smb_send_rqst(server, num_rqst, rqst, flags);
cifs_in_send_dec(server);
for (i = 0; i < num_rqst; i++)
cifs_save_when_sent(midQ[i]);
if (rc < 0) {
revert_current_mid(server, num_rqst);
server->sequence_number -= 2;
}
mutex_unlock(&server->srv_mutex);
/*
* If sending failed for some reason or it is an oplock break that we
* will not receive a response to - return credits back
*/
if (rc < 0 || (flags & CIFS_NO_SRV_RSP)) {
for (i = 0; i < num_rqst; i++)
add_credits(server, &credits[i], optype);
goto out;
}
/*
* At this point the request is passed to the network stack - we assume
* that any credits taken from the server structure on the client have
* been spent and we can't return them back. Once we receive responses
* we will collect credits granted by the server in the mid callbacks
* and add those credits to the server structure.
*/
/*
* Compounding is never used during session establish.
*/
spin_lock(&cifs_tcp_ses_lock);
if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP) || (optype & CIFS_SESS_OP)) {
spin_unlock(&cifs_tcp_ses_lock);
mutex_lock(&server->srv_mutex);
smb311_update_preauth_hash(ses, server, rqst[0].rq_iov, rqst[0].rq_nvec);
mutex_unlock(&server->srv_mutex);
spin_lock(&cifs_tcp_ses_lock);
}
spin_unlock(&cifs_tcp_ses_lock);
for (i = 0; i < num_rqst; i++) {
rc = wait_for_response(server, midQ[i]);
if (rc != 0)
break;
}
if (rc != 0) {
for (; i < num_rqst; i++) {
cifs_server_dbg(FYI, "Cancelling wait for mid %llu cmd: %d\n",
midQ[i]->mid, le16_to_cpu(midQ[i]->command));
send_cancel(server, &rqst[i], midQ[i]);
spin_lock(&GlobalMid_Lock);
midQ[i]->mid_flags |= MID_WAIT_CANCELLED;
if (midQ[i]->mid_state == MID_REQUEST_SUBMITTED) {
midQ[i]->callback = cifs_cancelled_callback;
cancelled_mid[i] = true;
credits[i].value = 0;
}
spin_unlock(&GlobalMid_Lock);
}
}
for (i = 0; i < num_rqst; i++) {
if (rc < 0)
goto out;
rc = cifs_sync_mid_result(midQ[i], server);
if (rc != 0) {
/* mark this mid as cancelled to not free it below */
cancelled_mid[i] = true;
goto out;
}
if (!midQ[i]->resp_buf ||
midQ[i]->mid_state != MID_RESPONSE_RECEIVED) {
rc = -EIO;
cifs_dbg(FYI, "Bad MID state?\n");
goto out;
}
buf = (char *)midQ[i]->resp_buf;
resp_iov[i].iov_base = buf;
resp_iov[i].iov_len = midQ[i]->resp_buf_size +
server->vals->header_preamble_size;
if (midQ[i]->large_buf)
resp_buf_type[i] = CIFS_LARGE_BUFFER;
else
resp_buf_type[i] = CIFS_SMALL_BUFFER;
rc = server->ops->check_receive(midQ[i], server,
flags & CIFS_LOG_ERROR);
/* mark it so buf will not be freed by cifs_delete_mid */
if ((flags & CIFS_NO_RSP_BUF) == 0)
midQ[i]->resp_buf = NULL;
}
/*
* Compounding is never used during session establish.
*/
spin_lock(&cifs_tcp_ses_lock);
if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP) || (optype & CIFS_SESS_OP)) {
struct kvec iov = {
.iov_base = resp_iov[0].iov_base,
.iov_len = resp_iov[0].iov_len
};
spin_unlock(&cifs_tcp_ses_lock);
mutex_lock(&server->srv_mutex);
smb311_update_preauth_hash(ses, server, &iov, 1);
mutex_unlock(&server->srv_mutex);
spin_lock(&cifs_tcp_ses_lock);
}
spin_unlock(&cifs_tcp_ses_lock);
out:
/*
* This will dequeue all mids. After this it is important that the
* demultiplex_thread will not process any of these mids any futher.
* This is prevented above by using a noop callback that will not
* wake this thread except for the very last PDU.
*/
for (i = 0; i < num_rqst; i++) {
if (!cancelled_mid[i])
cifs_delete_mid(midQ[i]);
}
return rc;
}
int
cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
struct TCP_Server_Info *server,
struct smb_rqst *rqst, int *resp_buf_type, const int flags,
struct kvec *resp_iov)
{
return compound_send_recv(xid, ses, server, flags, 1,
rqst, resp_buf_type, resp_iov);
}
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 s_iov[CIFS_MAX_IOV_SIZE], *new_iov;
int rc;
if (n_vec + 1 > CIFS_MAX_IOV_SIZE) {
new_iov = kmalloc_array(n_vec + 1, sizeof(struct kvec),
GFP_KERNEL);
if (!new_iov) {
/* otherwise cifs_send_recv below sets resp_buf_type */
*resp_buf_type = CIFS_NO_BUFFER;
return -ENOMEM;
}
} else
new_iov = s_iov;
/* 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, ses->server,
&rqst, resp_buf_type, flags, resp_iov);
if (n_vec + 1 > CIFS_MAX_IOV_SIZE)
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 flags)
{
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 };
struct cifs_credits credits = { .value = 1, .instance = 0 };
struct TCP_Server_Info *server;
if (ses == NULL) {
cifs_dbg(VFS, "Null smb session\n");
return -EIO;
}
server = ses->server;
if (server == NULL) {
cifs_dbg(VFS, "Null tcp session\n");
return -EIO;
}
spin_lock(&cifs_tcp_ses_lock);
if (server->tcpStatus == CifsExiting) {
spin_unlock(&cifs_tcp_ses_lock);
return -ENOENT;
}
spin_unlock(&cifs_tcp_ses_lock);
/* 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_server_dbg(VFS, "Invalid length, greater than maximum frame, %d\n",
len);
return -EIO;
}
rc = wait_for_free_request(server, flags, &credits.instance);
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(&server->srv_mutex);
rc = allocate_mid(ses, in_buf, &midQ);
if (rc) {
mutex_unlock(&server->srv_mutex);
/* Update # of requests on wire to server */
add_credits(server, &credits, 0);
return rc;
}
rc = cifs_sign_smb(in_buf, server, &midQ->sequence_number);
if (rc) {
mutex_unlock(&server->srv_mutex);
goto out;
}
midQ->mid_state = MID_REQUEST_SUBMITTED;
cifs_in_send_inc(server);
rc = smb_send(server, in_buf, len);
cifs_in_send_dec(server);
cifs_save_when_sent(midQ);
if (rc < 0)
server->sequence_number -= 2;
mutex_unlock(&server->srv_mutex);
if (rc < 0)
goto out;
rc = wait_for_response(server, midQ);
if (rc != 0) {
send_cancel(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(server, &credits, 0);
return rc;
}
spin_unlock(&GlobalMid_Lock);
}
rc = cifs_sync_mid_result(midQ, server);
if (rc != 0) {
add_credits(server, &credits, 0);
return rc;
}
if (!midQ->resp_buf || !out_buf ||
midQ->mid_state != MID_RESPONSE_RECEIVED) {
rc = -EIO;
cifs_server_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, server, 0);
out:
cifs_delete_mid(midQ);
add_credits(server, &credits, 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 };
unsigned int instance;
struct TCP_Server_Info *server;
if (tcon == NULL || tcon->ses == NULL) {
cifs_dbg(VFS, "Null smb session\n");
return -EIO;
}
ses = tcon->ses;
server = ses->server;
if (server == NULL) {
cifs_dbg(VFS, "Null tcp session\n");
return -EIO;
}
spin_lock(&cifs_tcp_ses_lock);
if (server->tcpStatus == CifsExiting) {
spin_unlock(&cifs_tcp_ses_lock);
return -ENOENT;
}
spin_unlock(&cifs_tcp_ses_lock);
/* 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_tcon_dbg(VFS, "Invalid length, greater than maximum frame, %d\n",
len);
return -EIO;
}
rc = wait_for_free_request(server, CIFS_BLOCKING_OP, &instance);
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(&server->srv_mutex);
rc = allocate_mid(ses, in_buf, &midQ);
if (rc) {
mutex_unlock(&server->srv_mutex);
return rc;
}
rc = cifs_sign_smb(in_buf, server, &midQ->sequence_number);
if (rc) {
cifs_delete_mid(midQ);
mutex_unlock(&server->srv_mutex);
return rc;
}
midQ->mid_state = MID_REQUEST_SUBMITTED;
cifs_in_send_inc(server);
rc = smb_send(server, in_buf, len);
cifs_in_send_dec(server);
cifs_save_when_sent(midQ);
if (rc < 0)
server->sequence_number -= 2;
mutex_unlock(&server->srv_mutex);
if (rc < 0) {
cifs_delete_mid(midQ);
return rc;
}
/* Wait for a reply - allow signals to interrupt. */
rc = wait_event_interruptible(server->response_q,
(!(midQ->mid_state == MID_REQUEST_SUBMITTED)) ||
((server->tcpStatus != CifsGood) &&
(server->tcpStatus != CifsNew)));
/* Were we interrupted by a signal ? */
spin_lock(&cifs_tcp_ses_lock);
if ((rc == -ERESTARTSYS) &&
(midQ->mid_state == MID_REQUEST_SUBMITTED) &&
((server->tcpStatus == CifsGood) ||
(server->tcpStatus == CifsNew))) {
spin_unlock(&cifs_tcp_ses_lock);
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(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(server, midQ);
if (rc) {
send_cancel(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;
spin_lock(&cifs_tcp_ses_lock);
}
spin_unlock(&cifs_tcp_ses_lock);
rc = cifs_sync_mid_result(midQ, server);
if (rc != 0)
return rc;
/* rcvd frame is ok */
if (out_buf == NULL || midQ->mid_state != MID_RESPONSE_RECEIVED) {
rc = -EIO;
cifs_tcon_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, server, 0);
out:
cifs_delete_mid(midQ);
if (rstart && rc == -EACCES)
return -ERESTARTSYS;
return rc;
}