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authorShyam Prasad N <sprasad@microsoft.com>2021-02-04 10:20:46 +0300
committerSteve French <stfrench@microsoft.com>2021-02-17 00:48:02 +0300
commit6d82c27ae5d048ba9219cccdf832f8406e507d5f (patch)
tree717c9516c046f248f786515e91fcec8a7214c0b0 /fs/cifs/transport.c
parent7de0394801da4f759684c4a33cf62f12da6e447d (diff)
downloadlinux-6d82c27ae5d048ba9219cccdf832f8406e507d5f.tar.xz
cifs: Identify a connection by a conn_id.
Introduced a new field conn_id in TCP_Server_Info structure. This is a non-persistent unique identifier maintained by the client for a connection to a file server. For this, a global counter named tcpSesNextId is maintained. On allocating a new TCP_Server_Info, this counter is incremented and assigned. Changed the dynamic tracepoints related to reconnects and crediting to be more informative (with conn_id printed). Debugging a crediting issue helped me understand the important things to print here. Always call dynamic tracepoints outside the scope of spinlocks. To do this, copy out the credits and in_flight fields of the server struct before dropping the lock. Signed-off-by: Shyam Prasad N <sprasad@microsoft.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/cifs/transport.c')
-rw-r--r--fs/cifs/transport.c53
1 files changed, 39 insertions, 14 deletions
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 39e87705840d..e90a1d1380b0 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -445,7 +445,7 @@ unmask:
*/
server->tcpStatus = CifsNeedReconnect;
trace_smb3_partial_send_reconnect(server->CurrentMid,
- server->hostname);
+ server->conn_id, server->hostname);
}
smbd_done:
if (rc < 0 && rc != -EINTR)
@@ -527,7 +527,7 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
int *credits;
int optype;
long int t;
- int scredits = server->credits;
+ int scredits, in_flight;
if (timeout < 0)
t = MAX_JIFFY_OFFSET;
@@ -551,22 +551,38 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
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->hostname, num_credits, 0);
+ server->conn_id, server->hostname, scredits,
+ num_credits, in_flight);
cifs_server_dbg(VFS, "wait timed out after %d ms\n",
- timeout);
+ timeout);
return -EBUSY;
}
if (rc == -ERESTARTSYS)
@@ -595,6 +611,7 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
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,
@@ -603,12 +620,17 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int 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->hostname, num_credits,
- 0);
+ server->CurrentMid,
+ server->conn_id, server->hostname,
+ scredits, num_credits, in_flight);
cifs_server_dbg(VFS, "wait timed out after %d ms\n",
- timeout);
+ timeout);
return -EBUSY;
}
if (rc == -ERESTARTSYS)
@@ -625,16 +647,18 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
/* update # of requests on the wire to server */
if ((flags & CIFS_TIMEOUT_MASK) != CIFS_BLOCKING_OP) {
*credits -= num_credits;
- scredits = *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->hostname, scredits, -(num_credits));
+ 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;
@@ -656,13 +680,13 @@ wait_for_compound_request(struct TCP_Server_Info *server, int num,
const int flags, unsigned int *instance)
{
int *credits;
- int scredits, sin_flight;
+ int scredits, in_flight;
credits = server->ops->get_credits_field(server, flags & CIFS_OP_MASK);
spin_lock(&server->req_lock);
scredits = *credits;
- sin_flight = server->in_flight;
+ in_flight = server->in_flight;
if (*credits < num) {
/*
@@ -684,9 +708,10 @@ wait_for_compound_request(struct TCP_Server_Info *server, int num,
if (server->in_flight == 0) {
spin_unlock(&server->req_lock);
trace_smb3_insufficient_credits(server->CurrentMid,
- server->hostname, scredits, sin_flight);
+ server->conn_id, server->hostname, scredits,
+ num, in_flight);
cifs_dbg(FYI, "%s: %d requests in flight, needed %d total=%d\n",
- __func__, sin_flight, num, scredits);
+ __func__, in_flight, num, scredits);
return -EDEADLK;
}
}