3 small smb3 fixes for stable

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Merge tag '5.11-rc6-smb3' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "Three small smb3 fixes for stable"

* tag '5.11-rc6-smb3' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: report error instead of invalid when revalidating a dentry fails
  smb3: fix crediting for compounding when only one request in flight
  smb3: Fix out-of-bounds bug in SMB2_negotiate()

fs/cifs/dir.c

@@ -737,6 +737,7 @@ static int
 cifs_d_revalidate(struct dentry *direntry, unsigned int flags)
 {
 	struct inode *inode;
+	int rc;
 
 	if (flags & LOOKUP_RCU)
 		return -ECHILD;
@@ -746,8 +747,25 @@ cifs_d_revalidate(struct dentry *direntry, unsigned int flags)
 		if ((flags & LOOKUP_REVAL) && !CIFS_CACHE_READ(CIFS_I(inode)))
 			CIFS_I(inode)->time = 0; /* force reval */
 
-		if (cifs_revalidate_dentry(direntry))
-			return 0;
+		rc = cifs_revalidate_dentry(direntry);
+		if (rc) {
+			cifs_dbg(FYI, "cifs_revalidate_dentry failed with rc=%d", rc);
+			switch (rc) {
+			case -ENOENT:
+			case -ESTALE:
+				/*
+				 * Those errors mean the dentry is invalid
+				 * (file was deleted or recreated)
+				 */
+				return 0;
+			default:
+				/*
+				 * Otherwise some unexpected error happened
+				 * report it as-is to VFS layer
+				 */
+				return rc;
+			}
+		}
 		else {
 			/*
 			 * If the inode wasn't known to be a dfs entry when

fs/cifs/smb2pdu.h

@@ -286,7 +286,7 @@ struct smb2_negotiate_req {
 	__le32 NegotiateContextOffset; /* SMB3.1.1 only. MBZ earlier */
 	__le16 NegotiateContextCount;  /* SMB3.1.1 only. MBZ earlier */
 	__le16 Reserved2;
-	__le16 Dialects[1]; /* One dialect (vers=) at a time for now */
+	__le16 Dialects[4]; /* BB expand this if autonegotiate > 4 dialects */
 } __packed;
 
 /* Dialects */

fs/cifs/transport.c

@@ -666,10 +666,22 @@ wait_for_compound_request(struct TCP_Server_Info *server, int num,
 
 	if (*credits < num) {
 		/*
-		 * Return immediately if not too many requests in flight since
-		 * we will likely be stuck on waiting for credits.
+		 * If the server is tight on resources or just gives us less
+		 * credits for other reasons (e.g. requests are coming out of
+		 * order and the server delays granting more credits until it
+		 * processes a missing mid) and we exhausted most available
+		 * credits there may be situations when we try to send
+		 * a compound request but we don't have enough credits. At this
+		 * point the client needs to decide if it should wait for
+		 * additional credits or fail the request. If at least one
+		 * request is in flight there is a high probability that the
+		 * server will return enough credits to satisfy this compound
+		 * request.
+		 *
+		 * Return immediately if no requests in flight since we will be
+		 * stuck on waiting for credits.
 		 */
-		if (server->in_flight < num - *credits) {
+		if (server->in_flight == 0) {
 			spin_unlock(&server->req_lock);
 			trace_smb3_insufficient_credits(server->CurrentMid,
 					server->hostname, scredits, sin_flight);