cifs: fix a credits leak for compund commands

When processing the mids for compounds we would only add credits based on
the last successful mid in the compound which would leak credits and
eventually triggering a re-connect.

Fix this by splitting the mid processing part into two loops instead of one
where the first loop just waits for all mids and then counts how many
credits we were granted for the whole compound.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index b48f43963da6afcc7ff7da565477b00e67d92877..333729cf46cdb82fffa174f2fc37f87697e19aa4 100644 (file)
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -786,7 +786,7 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
        int i, j, rc = 0;
        int timeout, optype;
        struct mid_q_entry *midQ[MAX_COMPOUND];
-       unsigned int credits = 1;
+       unsigned int credits = 0;
        char *buf;
 
        timeout = flags & CIFS_TIMEOUT_MASK;
@@ -851,17 +851,20 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 
        mutex_unlock(&ses->server->srv_mutex);
 
-       for (i = 0; i < num_rqst; i++) {
-               if (rc < 0)
-                       goto out;
+       if (rc < 0)
+               goto out;
 
-               if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP))
-                       smb311_update_preauth_hash(ses, rqst[i].rq_iov,
-                                                  rqst[i].rq_nvec);
+       /*
+        * Compounding is never used during session establish.
+        */
+       if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP))
+               smb311_update_preauth_hash(ses, rqst[0].rq_iov,
+                                          rqst[0].rq_nvec);
 
-               if (timeout == CIFS_ASYNC_OP)
-                       goto out;
+       if (timeout == CIFS_ASYNC_OP)
+               goto out;
 
+       for (i = 0; i < num_rqst; i++) {
                rc = wait_for_response(ses->server, midQ[i]);
                if (rc != 0) {
                        cifs_dbg(FYI, "Cancelling wait for mid %llu\n",
@@ -877,10 +880,21 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
                        }
                        spin_unlock(&GlobalMid_Lock);
                }
+       }
+
+       for (i = 0; i < num_rqst; i++)
+               if (midQ[i]->resp_buf)
+                       credits += ses->server->ops->get_credits(midQ[i]);
+       if (!credits)
+               credits = 1;
+
+       for (i = 0; i < num_rqst; i++) {
+               if (rc < 0)
+                       goto out;
 
                rc = cifs_sync_mid_result(midQ[i], ses->server);
                if (rc != 0) {
-                       add_credits(ses->server, 1, optype);
+                       add_credits(ses->server, credits, optype);
                        return rc;
                }
 
@@ -901,23 +915,26 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
                else
                        resp_buf_type[i] = CIFS_SMALL_BUFFER;
 
-               if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP)) {
-                       struct kvec iov = {
-                               .iov_base = resp_iov[i].iov_base,
-                               .iov_len = resp_iov[i].iov_len
-                       };
-                       smb311_update_preauth_hash(ses, &iov, 1);
-               }
-
-               credits = ses->server->ops->get_credits(midQ[i]);
-
                rc = ses->server->ops->check_receive(midQ[i], 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[i]->resp_buf = NULL;
+
        }
+
+       /*
+        * Compounding is never used during session establish.
+        */
+       if ((ses->status == CifsNew) || (optype & CIFS_NEG_OP)) {
+               struct kvec iov = {
+                       .iov_base = resp_iov[0].iov_base,
+                       .iov_len = resp_iov[0].iov_len
+               };
+               smb311_update_preauth_hash(ses, &iov, 1);
+       }
+
 out:
        /*
         * This will dequeue all mids. After this it is important that the