// 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 <linux/processor.h>
#include <linux/mempool.h>
#include <linux/sched/signal.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/task_work.h>
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "smb2proto.h"
#include "smbdirect.h"
#include "compress.h"
void
cifs_wake_up_task(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
if (mid->mid_state == MID_RESPONSE_RECEIVED)
mid->mid_state = MID_RESPONSE_READY;
wake_up_process(mid->callback_data);
}
void __release_mid(struct TCP_Server_Info *server, struct mid_q_entry *midEntry)
{
#ifdef CONFIG_CIFS_STATS2
__le16 command = server->vals->lock_cmd;
__u16 smb_cmd = le16_to_cpu(midEntry->command);
unsigned long now;
unsigned long roundtrip_time;
#endif
if (midEntry->resp_buf && (midEntry->wait_cancelled) &&
(midEntry->mid_state == MID_RESPONSE_RECEIVED ||
midEntry->mid_state == MID_RESPONSE_READY) &&
server->ops->handle_cancelled_mid)
server->ops->handle_cancelled_mid(midEntry, server);
midEntry->mid_state = MID_FREE;
atomic_dec(&mid_count);
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_pool);
}
void
delete_mid(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
spin_lock(&server->mid_queue_lock);
if (!mid->deleted_from_q) {
list_del_init(&mid->qhead);
mid->deleted_from_q = true;
}
spin_unlock(&server->mid_queue_lock);
release_mid(server, 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.
*/
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;
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.
*
* Even if regular signals are masked, EINTR might be
* propagated from sk_stream_wait_memory() to here when
* TIF_NOTIFY_SIGNAL is used for task work. For example,
* certain io_uring completions will use that. Treat
* having EINTR with pending task work the same as EAGAIN
* to avoid unnecessary reconnects.
*/
rc = sock_sendmsg(ssocket, smb_msg);
if (rc == -EAGAIN || unlikely(rc == -EINTR && task_work_pending(current))) {
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 (!is_smb1(server) && 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;
buflen += iov_iter_count(&rqst->rq_iter);
return buflen;
}
int __smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
struct smb_rqst *rqst)
{
int rc;
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;
cifs_in_send_inc(server);
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;
}
rc = -EAGAIN;
if (ssocket == NULL)
goto out;
rc = -ERESTARTSYS;
if (fatal_signal_pending(current)) {
cifs_dbg(FYI, "signal pending before send request\n");
goto out;
}
rc = 0;
/* 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 */
{
struct kvec hiov = {
.iov_base = &rfc1002_marker,
.iov_len = 4
};
iov_iter_kvec(&smb_msg.msg_iter, ITER_SOURCE, &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, ITER_SOURCE, iov, n_vec, size);
rc = smb_send_kvec(server, &smb_msg, &sent);
if (rc < 0)
goto unmask;
total_len += sent;
if (iov_iter_count(&rqst[j].rq_iter) > 0) {
smb_msg.msg_iter = rqst[j].rq_iter;
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->current_mid,
server->conn_id, server->hostname);
}
smbd_done:
/*
* there's hardly any use for the layers above to know the
* actual error code here. All they should do at this point is
* to retry the connection and hope it goes away.
*/
if (rc < 0 && rc != -EINTR && rc != -EAGAIN) {
cifs_server_dbg(VFS, "Error %d sending data on socket to server\n",
rc);
rc = -ECONNABORTED;
cifs_signal_cifsd_for_reconnect(server, false);
} else if (rc > 0)
rc = 0;
out:
cifs_in_send_dec(server);
return rc;
}
static int
smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
struct smb_rqst *rqst, int flags)
{
struct smb2_transform_hdr tr_hdr;
struct smb_rqst new_rqst[MAX_COMPOUND] = {};
struct kvec iov = {
.iov_base = &tr_hdr,
.iov_len = sizeof(tr_hdr),
};
int rc;
if (flags & CIFS_COMPRESS_REQ)
return smb_compress(server, &rqst[0], __smb_send_rqst);
if (!(flags & CIFS_TRANSFORM_REQ))
return __smb_send_rqst(server, num_rqst, rqst);
if (WARN_ON_ONCE(num_rqst > MAX_COMPOUND - 1))
return smb_EIO1(smb_eio_trace_tx_max_compound, num_rqst);
if (!server->ops->init_transform_rq) {
cifs_server_dbg(VFS, "Encryption requested but transform callback is missing\n");
return smb_EIO(smb_eio_trace_tx_need_transform);
}
new_rqst[0].rq_iov = &iov;
new_rqst[0].rq_nvec = 1;
rc = server->ops->init_transform_rq(server, num_rqst + 1,
new_rqst, rqst);
if (!rc) {
rc = __smb_send_rqst(server, num_rqst + 1, new_rqst);
smb3_free_compound_rqst(num_rqst, &new_rqst[1]);
}
return rc;
}
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_nblk_credits(server->current_mid,
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) {
spin_unlock(&server->req_lock);
spin_lock(&server->srv_lock);
if (server->tcpStatus == CifsExiting) {
spin_unlock(&server->srv_lock);
return -ENOENT;
}
spin_unlock(&server->srv_lock);
spin_lock(&server->req_lock);
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->current_mid,
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 {
/*
* 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.
*/
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->current_mid,
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_waitff_credits(server->current_mid,
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;
}
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->current_mid,
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, size_t size,
size_t *num, struct cifs_credits *credits)
{
*num = size;
credits->value = 0;
credits->instance = server->reconnect_instance;
return 0;
}
int wait_for_response(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
unsigned int sleep_state = TASK_KILLABLE;
int error;
if (mid->sr_flags & CIFS_INTERRUPTIBLE_WAIT)
sleep_state = TASK_INTERRUPTIBLE;
error = wait_event_state(server->response_q,
mid->mid_state != MID_REQUEST_SUBMITTED &&
mid->mid_state != MID_RESPONSE_RECEIVED,
(sleep_state | TASK_FREEZABLE_UNSAFE));
if (error < 0)
return -ERESTARTSYS;
return 0;
}
/*
* 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;
cifs_server_lock(server);
/*
* 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) {
cifs_server_unlock(server);
add_credits_and_wake_if(server, &credits, optype);
return -EAGAIN;
}
mid = server->ops->setup_async_request(server, rqst);
if (IS_ERR(mid)) {
cifs_server_unlock(server);
add_credits_and_wake_if(server, &credits, optype);
return PTR_ERR(mid);
}
mid->sr_flags = flags;
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(&server->mid_queue_lock);
list_add_tail(&mid->qhead, &server->pending_mid_q);
spin_unlock(&server->mid_queue_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);
rc = smb_send_rqst(server, 1, rqst, flags);
if (rc < 0) {
revert_current_mid(server, mid->credits);
server->sequence_number -= 2;
delete_mid(server, mid);
}
cifs_server_unlock(server);
if (rc == 0)
return 0;
add_credits_and_wake_if(server, &credits, optype);
return rc;
}
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(&server->mid_queue_lock);
switch (mid->mid_state) {
case MID_RESPONSE_READY:
spin_unlock(&server->mid_queue_lock);
return rc;
case MID_RETRY_NEEDED:
rc = -EAGAIN;
break;
case MID_RESPONSE_MALFORMED:
rc = smb_EIO(smb_eio_trace_rx_sync_mid_malformed);
break;
case MID_SHUTDOWN:
rc = -EHOSTDOWN;
break;
case MID_RC:
rc = mid->mid_rc;
break;
default:
if (mid->deleted_from_q == false) {
list_del_init(&mid->qhead);
mid->deleted_from_q = true;
}
spin_unlock(&server->mid_queue_lock);
cifs_server_dbg(VFS, "%s: invalid mid state mid=%llu state=%d\n",
__func__, mid->mid, mid->mid_state);
rc = smb_EIO1(smb_eio_trace_rx_sync_mid_invalid, mid->mid_state);
goto sync_mid_done;
}
spin_unlock(&server->mid_queue_lock);
sync_mid_done:
release_mid(server, mid);
return rc;
}
static void
cifs_compound_callback(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
struct cifs_credits credits = {
.value = server->ops->get_credits(mid),
.instance = server->reconnect_instance,
};
add_credits(server, &credits, mid->optype);
if (mid->mid_state == MID_RESPONSE_RECEIVED)
mid->mid_state = MID_RESPONSE_READY;
}
static void
cifs_compound_last_callback(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
cifs_compound_callback(server, mid);
cifs_wake_up_task(server, mid);
}
static void
cifs_cancelled_callback(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
cifs_compound_callback(server, mid);
release_mid(server, mid);
}
/*
* cifs_pick_channel - pick an eligible channel for network operations
*
* @ses: session reference
*
* Select an eligible channel (not terminating and not marked as needing
* reconnect), preferring the least loaded one. If no eligible channel is
* found, fall back to the primary channel (index 0).
*
* Return: TCP_Server_Info pointer for the chosen channel, or NULL if @ses is
* NULL.
*/
struct TCP_Server_Info *cifs_pick_channel(struct cifs_ses *ses)
{
uint index = 0;
unsigned int min_in_flight = UINT_MAX;
struct TCP_Server_Info *server = NULL;
int i, start, cur;
if (!ses)
return NULL;
spin_lock(&ses->chan_lock);
start = atomic_inc_return(&ses->chan_seq);
for (i = 0; i < ses->chan_count; i++) {
cur = (start + i) % ses->chan_count;
server = ses->chans[cur].server;
if (!server || server->terminate)
continue;
if (CIFS_CHAN_NEEDS_RECONNECT(ses, cur))
continue;
/*
* strictly speaking, we should pick up req_lock to read
* server->in_flight. But it shouldn't matter much here if we
* race while reading this data. The worst that can happen is
* that we could use a channel that's not least loaded. Avoiding
* taking the lock could help reduce wait time, which is
* important for this function
*/
if (server->in_flight < min_in_flight) {
min_in_flight = server->in_flight;
index = cur;
}
}
server = ses->chans[index].server;
spin_unlock(&ses->chan_lock);
return 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 *mid[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 smb_EIO(smb_eio_trace_null_pointers);
}
spin_lock(&server->srv_lock);
if (server->tcpStatus == CifsExiting) {
spin_unlock(&server->srv_lock);
return -ENOENT;
}
spin_unlock(&server->srv_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.
*/
cifs_server_lock(server);
/*
* 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) {
cifs_server_unlock(server);
for (j = 0; j < num_rqst; j++)
add_credits(server, &credits[j], optype);
return -EAGAIN;
}
for (i = 0; i < num_rqst; i++) {
mid[i] = server->ops->setup_request(ses, server, &rqst[i]);
if (IS_ERR(mid[i])) {
revert_current_mid(server, i);
for (j = 0; j < i; j++)
delete_mid(server, mid[j]);
cifs_server_unlock(server);
/* Update # of requests on wire to server */
for (j = 0; j < num_rqst; j++)
add_credits(server, &credits[j], optype);
return PTR_ERR(mid[i]);
}
mid[i]->sr_flags = flags;
mid[i]->mid_state = MID_REQUEST_SUBMITTED;
mid[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)
mid[i]->callback = cifs_compound_callback;
else
mid[i]->callback = cifs_compound_last_callback;
}
rc = smb_send_rqst(server, num_rqst, rqst, flags);
for (i = 0; i < num_rqst; i++)
cifs_save_when_sent(mid[i]);
if (rc < 0) {
revert_current_mid(server, num_rqst);
server->sequence_number -= 2;
}
cifs_server_unlock(server);
/*
* 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(&ses->ses_lock);
if ((ses->ses_status == SES_NEW) || (optype & CIFS_NEG_OP) || (optype & CIFS_SESS_OP)) {
spin_unlock(&ses->ses_lock);
if (WARN_ON_ONCE(num_rqst != 1 || !resp_iov))
return -EINVAL;
cifs_server_lock(server);
smb311_update_preauth_hash(ses, server, rqst[0].rq_iov, rqst[0].rq_nvec);
cifs_server_unlock(server);
spin_lock(&ses->ses_lock);
}
spin_unlock(&ses->ses_lock);
for (i = 0; i < num_rqst; i++) {
rc = wait_for_response(server, mid[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",
mid[i]->mid, le16_to_cpu(mid[i]->command));
send_cancel(ses, server, &rqst[i], mid[i], xid);
spin_lock(&mid[i]->mid_lock);
mid[i]->wait_cancelled = true;
if (mid[i]->mid_state == MID_REQUEST_SUBMITTED ||
mid[i]->mid_state == MID_RESPONSE_RECEIVED) {
mid[i]->callback = cifs_cancelled_callback;
cancelled_mid[i] = true;
credits[i].value = 0;
}
spin_unlock(&mid[i]->mid_lock);
}
}
for (i = 0; i < num_rqst; i++) {
if (rc < 0)
goto out;
rc = cifs_sync_mid_result(mid[i], server);
if (rc != 0) {
/* mark this mid as cancelled to not free it below */
cancelled_mid[i] = true;
goto out;
}
if (!mid[i]->resp_buf ||
mid[i]->mid_state != MID_RESPONSE_READY) {
rc = smb_EIO1(smb_eio_trace_rx_mid_unready, mid[i]->mid_state);
cifs_dbg(FYI, "Bad MID state?\n");
goto out;
}
rc = server->ops->check_receive(mid[i], server,
flags & CIFS_LOG_ERROR);
if (resp_iov) {
buf = (char *)mid[i]->resp_buf;
resp_iov[i].iov_base = buf;
resp_iov[i].iov_len = mid[i]->resp_buf_size;
if (mid[i]->large_buf)
resp_buf_type[i] = CIFS_LARGE_BUFFER;
else
resp_buf_type[i] = CIFS_SMALL_BUFFER;
/* mark it so buf will not be freed by delete_mid */
if ((flags & CIFS_NO_RSP_BUF) == 0)
mid[i]->resp_buf = NULL;
}
}
/*
* Compounding is never used during session establish.
*/
spin_lock(&ses->ses_lock);
if ((ses->ses_status == SES_NEW) || (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(&ses->ses_lock);
cifs_server_lock(server);
smb311_update_preauth_hash(ses, server, &iov, 1);
cifs_server_unlock(server);
spin_lock(&ses->ses_lock);
}
spin_unlock(&ses->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 further.
* 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])
delete_mid(server, mid[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);
}
/*
* Discard any remaining data in the current SMB. To do this, we borrow the
* current bigbuf.
*/
int
cifs_discard_remaining_data(struct TCP_Server_Info *server)
{
unsigned int rfclen = server->pdu_size;
size_t remaining = rfclen - server->total_read;
while (remaining > 0) {
ssize_t length;
length = cifs_discard_from_socket(server,
min_t(size_t, remaining,
CIFSMaxBufSize + MAX_HEADER_SIZE(server)));
if (length < 0)
return length;
server->total_read += length;
remaining -= length;
}
return 0;
}
static int
__cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid,
bool malformed)
{
int length;
length = cifs_discard_remaining_data(server);
dequeue_mid(server, mid, malformed);
mid->resp_buf = server->smallbuf;
server->smallbuf = NULL;
return length;
}
static int
cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
struct cifs_io_subrequest *rdata = mid->callback_data;
return __cifs_readv_discard(server, mid, rdata->result);
}
int
cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
int length, len;
unsigned int data_offset, data_len, end_off;
struct cifs_io_subrequest *rdata = mid->callback_data;
char *buf = server->smallbuf;
unsigned int buflen = server->pdu_size;
bool use_rdma_mr = false;
cifs_dbg(FYI, "%s: mid=%llu offset=%llu bytes=%zu\n",
__func__, mid->mid, rdata->subreq.start, rdata->subreq.len);
/*
* read the rest of READ_RSP header (sans Data array), or whatever we
* can if there's not enough data. At this point, we've read down to
* the Mid.
*/
len = min_t(unsigned int, buflen, server->vals->read_rsp_size) -
HEADER_SIZE(server) + 1;
length = cifs_read_from_socket(server,
buf + HEADER_SIZE(server) - 1, len);
if (length < 0)
return length;
server->total_read += length;
if (server->ops->is_session_expired &&
server->ops->is_session_expired(buf)) {
cifs_reconnect(server, true);
return -1;
}
if (server->ops->is_status_pending &&
server->ops->is_status_pending(buf, server)) {
cifs_discard_remaining_data(server);
return -1;
}
/* set up first two iov for signature check and to get credits */
rdata->iov[0].iov_base = buf;
rdata->iov[0].iov_len = server->total_read;
cifs_dbg(FYI, "0: iov_base=%p iov_len=%zu\n",
rdata->iov[0].iov_base, rdata->iov[0].iov_len);
/* Was the SMB read successful? */
rdata->result = server->ops->map_error(buf, false);
if (rdata->result != 0) {
cifs_dbg(FYI, "%s: server returned error %d\n",
__func__, rdata->result);
/* normal error on read response */
return __cifs_readv_discard(server, mid, false);
}
/* Is there enough to get to the rest of the READ_RSP header? */
if (server->total_read < server->vals->read_rsp_size) {
cifs_dbg(FYI, "%s: server returned short header. got=%u expected=%zu\n",
__func__, server->total_read,
server->vals->read_rsp_size);
rdata->result = smb_EIO2(smb_eio_trace_read_rsp_short,
server->total_read, server->vals->read_rsp_size);
return cifs_readv_discard(server, mid);
}
data_offset = server->ops->read_data_offset(buf);
if (data_offset < server->total_read) {
/*
* win2k8 sometimes sends an offset of 0 when the read
* is beyond the EOF. Treat it as if the data starts just after
* the header.
*/
cifs_dbg(FYI, "%s: data offset (%u) inside read response header\n",
__func__, data_offset);
data_offset = server->total_read;
} else if (data_offset > MAX_CIFS_SMALL_BUFFER_SIZE) {
/* data_offset is beyond the end of smallbuf */
cifs_dbg(FYI, "%s: data offset (%u) beyond end of smallbuf\n",
__func__, data_offset);
rdata->result = smb_EIO1(smb_eio_trace_read_overlarge,
data_offset);
return cifs_readv_discard(server, mid);
}
cifs_dbg(FYI, "%s: total_read=%u data_offset=%u\n",
__func__, server->total_read, data_offset);
len = data_offset - server->total_read;
if (len > 0) {
/* read any junk before data into the rest of smallbuf */
length = cifs_read_from_socket(server,
buf + server->total_read, len);
if (length < 0)
return length;
server->total_read += length;
rdata->iov[0].iov_len = server->total_read;
}
/* how much data is in the response? */
#ifdef CONFIG_CIFS_SMB_DIRECT
use_rdma_mr = rdata->mr;
#endif
data_len = server->ops->read_data_length(buf, use_rdma_mr);
if (!use_rdma_mr) {
if (check_add_overflow(data_offset, data_len, &end_off) ||
end_off > buflen) {
/* data_len is corrupt -- discard frame */
rdata->result = smb_EIO2(smb_eio_trace_read_rsp_malformed,
end_off, buflen);
return cifs_readv_discard(server, mid);
}
}
#ifdef CONFIG_CIFS_SMB_DIRECT
if (rdata->mr)
length = data_len; /* An RDMA read is already done. */
else
#endif
length = cifs_read_iter_from_socket(server, &rdata->subreq.io_iter,
data_len);
if (length > 0)
rdata->got_bytes += length;
server->total_read += length;
cifs_dbg(FYI, "total_read=%u buflen=%u remaining=%u\n",
server->total_read, buflen, data_len);
/* discard anything left over */
if (server->total_read < buflen)
return cifs_readv_discard(server, mid);
dequeue_mid(server, mid, false);
mid->resp_buf = server->smallbuf;
server->smallbuf = NULL;
return length;
}
