cifs: add a warning when the in-flight count goes negative

We've seen the in-flight count go into negative with some
internal stress testing in Microsoft.

Adding a WARN when this happens, in hope of understanding
why this happens when it happens.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 9b42028e08b626eddc59c12d0bf667d276cd3744..221c6b1ee3775ae56cad9b425ce6c69ee41a15b3 100644 (file)
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -93,6 +93,7 @@ smb2_add_credits(struct TCP_Server_Info *server,
                                            server->conn_id, server->hostname, *val,
                                            add, server->in_flight);
        }
+       WARN_ON_ONCE(server->in_flight == 0);
        server->in_flight--;
        if (server->in_flight == 0 &&
           ((optype & CIFS_OP_MASK) != CIFS_NEG_OP) &&