CIFS: Check for reconnects before sending async requests

The reconnect might have happended after we obtained credits
and before we acquired srv_mutex. Check for that under the mutex
and retry an async operation if the reconnect is detected.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 7a9a9fd..9e8394f 100644 (file)
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -93,7 +93,8 @@ extern int cifs_discard_remaining_data(struct TCP_Server_Info *server);
 extern 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);
+                       mid_handle_t *handle, void *cbdata, const int flags,
+                       const struct cifs_credits *exist_credits);
 extern int cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
                          struct smb_rqst *rqst, int *resp_buf_type,
                          const int flags, struct kvec *resp_iov);

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index d4f9440..f9a37e9 100644 (file)
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -860,7 +860,7 @@ CIFSSMBEcho(struct TCP_Server_Info *server)
        iov[1].iov_base = (char *)smb + 4;
 
        rc = cifs_call_async(server, &rqst, NULL, cifs_echo_callback, NULL,
-                            server, CIFS_ASYNC_OP | CIFS_ECHO_OP);
+                            server, CIFS_ASYNC_OP | CIFS_ECHO_OP, NULL);
        if (rc)
                cifs_dbg(FYI, "Echo request failed: %d\n", rc);
 
@@ -1812,7 +1812,7 @@ cifs_async_readv(struct cifs_readdata *rdata)
 
        kref_get(&rdata->refcount);
        rc = cifs_call_async(tcon->ses->server, &rqst, cifs_readv_receive,
-                            cifs_readv_callback, NULL, rdata, 0);
+                            cifs_readv_callback, NULL, rdata, 0, NULL);
 
        if (rc == 0)
                cifs_stats_inc(&tcon->stats.cifs_stats.num_reads);
@@ -2352,7 +2352,7 @@ cifs_async_writev(struct cifs_writedata *wdata,
 
        kref_get(&wdata->refcount);
        rc = cifs_call_async(tcon->ses->server, &rqst, NULL,
-                               cifs_writev_callback, NULL, wdata, 0);
+                            cifs_writev_callback, NULL, wdata, 0, NULL);
 
        if (rc == 0)
                cifs_stats_inc(&tcon->stats.cifs_stats.num_writes);

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 7d8f1d2..7105312 100644 (file)
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -3034,7 +3034,7 @@ SMB2_echo(struct TCP_Server_Info *server)
        iov[0].iov_base = (char *)req;
 
        rc = cifs_call_async(server, &rqst, NULL, smb2_echo_callback, NULL,
-                            server, CIFS_ECHO_OP);
+                            server, CIFS_ECHO_OP, NULL);
        if (rc)
                cifs_dbg(FYI, "Echo request failed: %d\n", rc);
 
@@ -3343,7 +3343,8 @@ smb2_async_readv(struct cifs_readdata *rdata)
        kref_get(&rdata->refcount);
        rc = cifs_call_async(io_parms.tcon->ses->server, &rqst,
                             cifs_readv_receive, smb2_readv_callback,
-                            smb3_handle_read_data, rdata, flags);
+                            smb3_handle_read_data, rdata, flags,
+                            &rdata->credits);
        if (rc) {
                kref_put(&rdata->refcount, cifs_readdata_release);
                cifs_stats_fail_inc(io_parms.tcon, SMB2_READ_HE);
@@ -3645,7 +3646,7 @@ smb2_async_writev(struct cifs_writedata *wdata,
 
        kref_get(&wdata->refcount);
        rc = cifs_call_async(server, &rqst, NULL, smb2_writev_callback, NULL,
-                            wdata, flags);
+                            wdata, flags, &wdata->credits);
 
        if (rc) {
                trace_smb3_write_err(0 /* no xid */, req->PersistentFileId,

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 0ee36c3..5a3e499 100644 (file)
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -607,7 +607,8 @@ cifs_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 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)
+               mid_handle_t *handle, void *cbdata, const int flags,
+               const struct cifs_credits *exist_credits)
 {
        int rc, timeout, optype;
        struct mid_q_entry *mid;
@@ -623,9 +624,22 @@ cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
                        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);