CIFS: Fix an issue with re-sending rdata when transport returning -EAGAIN

When sending a rdata, transport may return -EAGAIN. In this case
we should re-obtain credits because the session may have been
reconnected.

Change in v2: adjust_credits before re-sending

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

1 files changed, 41 insertions, 30 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 2aa3e62af764..89006e044973 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3361,44 +3361,55 @@ static int cifs_resend_rdata(struct cifs_readdata *rdata,
         struct TCP_Server_Info *server =
                 tlink_tcon(rdata->cfile->tlink)->ses->server;
 
-        /*
-         * Wait for credits to resend this rdata.
-         * Note: we are attempting to resend the whole rdata not in segments
-         */
         do {
-                rc = server->ops->wait_mtu_credits(server, rdata->bytes,
+                if (rdata->cfile->invalidHandle) {
+                        rc = cifs_reopen_file(rdata->cfile, true);
+                        if (rc == -EAGAIN)
+                                continue;
+                        else if (rc)
+                                break;
+                }
+
+                /*
+                 * Wait for credits to resend this rdata.
+                 * Note: we are attempting to resend the whole rdata not in
+                 * segments
+                 */
+                do {
+                        rc = server->ops->wait_mtu_credits(server, rdata->bytes,
                                                 &rsize, &credits);
 
-                if (rc)
-                        goto out;
+                        if (rc)
+                                goto fail;
 
-                if (rsize < rdata->bytes) {
-                        add_credits_and_wake_if(server, &credits, 0);
-                        msleep(1000);
-                }
-        } while (rsize < rdata->bytes);
+                        if (rsize < rdata->bytes) {
+                                add_credits_and_wake_if(server, &credits, 0);
+                                msleep(1000);
+                        }
+                } while (rsize < rdata->bytes);
+                rdata->credits = credits;
 
-        rdata->credits = credits;
-        rc = -EAGAIN;
-        while (rc == -EAGAIN) {
-                rc = 0;
-                if (rdata->cfile->invalidHandle)
-                        rc = cifs_reopen_file(rdata->cfile, true);
-                if (!rc)
-                        rc = server->ops->async_readv(rdata);
-        }
+                rc = adjust_credits(server, &rdata->credits, rdata->bytes);
+                if (!rc) {
+                        if (rdata->cfile->invalidHandle)
+                                rc = -EAGAIN;
+                        else
+                                rc = server->ops->async_readv(rdata);
+                }
 
-        if (!rc) {
-                /* Add to aio pending list */
-                list_add_tail(&rdata->list, rdata_list);
-                return 0;
-        }
+                /* If the read was successfully sent, we are done */
+                if (!rc) {
+                        /* Add to aio pending list */
+                        list_add_tail(&rdata->list, rdata_list);
+                        return 0;
+                }
 
-        add_credits_and_wake_if(server, &rdata->credits, 0);
-out:
-        kref_put(&rdata->refcount,
-                cifs_uncached_readdata_release);
+                /* Roll back credits and retry if needed */
+                add_credits_and_wake_if(server, &rdata->credits, 0);
+        } while (rc == -EAGAIN);
 
+fail:
+        kref_put(&rdata->refcount, cifs_uncached_readdata_release);
         return rc;
 }