ksmbd: add continuous availability share parameter

If capabilities of the share is not SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY,
ksmbd should not grant a persistent handle to the client.
This patch add continuous availability share parameter to control it.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/server/ksmbd_netlink.h

@@ -340,23 +340,24 @@ enum KSMBD_TREE_CONN_STATUS {
 /*
  * Share config flags.
  */
-#define KSMBD_SHARE_FLAG_INVALID		(0)
-#define KSMBD_SHARE_FLAG_AVAILABLE		BIT(0)
-#define KSMBD_SHARE_FLAG_BROWSEABLE		BIT(1)
-#define KSMBD_SHARE_FLAG_WRITEABLE		BIT(2)
-#define KSMBD_SHARE_FLAG_READONLY		BIT(3)
-#define KSMBD_SHARE_FLAG_GUEST_OK		BIT(4)
-#define KSMBD_SHARE_FLAG_GUEST_ONLY		BIT(5)
-#define KSMBD_SHARE_FLAG_STORE_DOS_ATTRS	BIT(6)
-#define KSMBD_SHARE_FLAG_OPLOCKS		BIT(7)
-#define KSMBD_SHARE_FLAG_PIPE			BIT(8)
-#define KSMBD_SHARE_FLAG_HIDE_DOT_FILES		BIT(9)
-#define KSMBD_SHARE_FLAG_INHERIT_OWNER		BIT(10)
-#define KSMBD_SHARE_FLAG_STREAMS		BIT(11)
-#define KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS	BIT(12)
-#define KSMBD_SHARE_FLAG_ACL_XATTR		BIT(13)
-#define KSMBD_SHARE_FLAG_UPDATE			BIT(14)
-#define KSMBD_SHARE_FLAG_CROSSMNT		BIT(15)
+#define KSMBD_SHARE_FLAG_INVALID			(0)
+#define KSMBD_SHARE_FLAG_AVAILABLE			BIT(0)
+#define KSMBD_SHARE_FLAG_BROWSEABLE			BIT(1)
+#define KSMBD_SHARE_FLAG_WRITEABLE			BIT(2)
+#define KSMBD_SHARE_FLAG_READONLY			BIT(3)
+#define KSMBD_SHARE_FLAG_GUEST_OK			BIT(4)
+#define KSMBD_SHARE_FLAG_GUEST_ONLY			BIT(5)
+#define KSMBD_SHARE_FLAG_STORE_DOS_ATTRS		BIT(6)
+#define KSMBD_SHARE_FLAG_OPLOCKS			BIT(7)
+#define KSMBD_SHARE_FLAG_PIPE				BIT(8)
+#define KSMBD_SHARE_FLAG_HIDE_DOT_FILES			BIT(9)
+#define KSMBD_SHARE_FLAG_INHERIT_OWNER			BIT(10)
+#define KSMBD_SHARE_FLAG_STREAMS			BIT(11)
+#define KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS		BIT(12)
+#define KSMBD_SHARE_FLAG_ACL_XATTR			BIT(13)
+#define KSMBD_SHARE_FLAG_UPDATE				BIT(14)
+#define KSMBD_SHARE_FLAG_CROSSMNT			BIT(15)
+#define KSMBD_SHARE_FLAG_CONTINUOUS_AVAILABILITY	BIT(16)
 
 /*
  * Tree connect request flags.

fs/smb/server/smb2pdu.c

@@ -1988,7 +1988,12 @@ int smb2_tree_connect(struct ksmbd_work *work)
 	write_unlock(&sess->tree_conns_lock);
 	rsp->StructureSize = cpu_to_le16(16);
 out_err1:
-	rsp->Capabilities = 0;
+	if (server_conf.flags & KSMBD_GLOBAL_FLAG_DURABLE_HANDLE &&
+	    test_share_config_flag(share,
+				   KSMBD_SHARE_FLAG_CONTINUOUS_AVAILABILITY))
+		rsp->Capabilities = SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY;
+	else
+		rsp->Capabilities = 0;
 	rsp->Reserved = 0;
 	/* default manual caching */
 	rsp->ShareFlags = SMB2_SHAREFLAG_MANUAL_CACHING;
@@ -3502,7 +3507,9 @@ int smb2_open(struct ksmbd_work *work)
 	memcpy(fp->client_guid, conn->ClientGUID, SMB2_CLIENT_GUID_SIZE);
 
 	if (dh_info.type == DURABLE_REQ_V2 || dh_info.type == DURABLE_REQ) {
-		if (dh_info.type == DURABLE_REQ_V2 && dh_info.persistent)
+		if (dh_info.type == DURABLE_REQ_V2 && dh_info.persistent &&
+		    test_share_config_flag(work->tcon->share_conf,
+					   KSMBD_SHARE_FLAG_CONTINUOUS_AVAILABILITY))
 			fp->is_persistent = true;
 		else
 			fp->is_durable = true;