From: Shyam Prasad N <sprasad@microsoft.com>
Date: Wed, 3 Feb 2021 22:58:38 -0800
Subject: [PATCH] cifs: Fix in error types returned for out-of-credit
 situations.
Git-commit: 7de0394801da4f759684c4a33cf62f12da6e447d
References: bsc#1190317
Patch-mainline: v5.12-rc1

For failure by timeout waiting for credits, changed the error
returned to the app with EBUSY, instead of ENOTSUPP. This is done
because this situation is possible even in non-buggy cases. i.e.
overloaded server can return 0 credits until done with outstanding
requests. And this feels like a better error to return to the app.

For cases of zero credits found even when there are no requests
in flight, replaced ENOTSUPP with EDEADLK, since we're avoiding
deadlock here by returning error.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
 fs/cifs/transport.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 41223a9ee086..39e87705840d 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -567,7 +567,7 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
 					server->hostname, num_credits, 0);
 				cifs_server_dbg(VFS, "wait timed out after %d ms\n",
 					 timeout);
-				return -ENOTSUPP;
+				return -EBUSY;
 			}
 			if (rc == -ERESTARTSYS)
 				return -ERESTARTSYS;
@@ -609,7 +609,7 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
 						0);
 					cifs_server_dbg(VFS, "wait timed out after %d ms\n",
 						 timeout);
-					return -ENOTSUPP;
+					return -EBUSY;
 				}
 				if (rc == -ERESTARTSYS)
 					return -ERESTARTSYS;
@@ -687,7 +687,7 @@ wait_for_compound_request(struct TCP_Server_Info *server, int num,
 					server->hostname, scredits, sin_flight);
 			cifs_dbg(FYI, "%s: %d requests in flight, needed %d total=%d\n",
 					__func__, sin_flight, num, scredits);
-			return -ENOTSUPP;
+			return -EDEADLK;
 		}
 	}
 	spin_unlock(&server->req_lock);
-- 
2.33.0