Commit 501ae8ec authored Sep 04, 2019 by Michael S. Tsirkin Committed by Miklos Szeredi Sep 12, 2019

fuse: reserve byteswapped init opcodes



virtio fs tunnels fuse over a virtio channel.  One issue is two sides might
be speaking different endian-ness. To detects this, host side looks at the
opcode value in the FUSE_INIT command.  Works fine at the moment but might
fail if a future version of fuse will use such an opcode for
initialization.  Let's reserve this opcode so we remember and don't do
this.

Same for CUSE_INIT.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

parent 15c8e72e

include/uapi/linux/fuse.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -425,6 +425,10 @@ enum fuse_opcode {

		/* CUSE specific operations */
		CUSE_INIT = 4096,

		/* Reserved opcodes: helpful to detect structure endian-ness */
		CUSE_INIT_BSWAP_RESERVED = 1048576, /* CUSE_INIT << 8 */
		FUSE_INIT_BSWAP_RESERVED = 436207616, /* FUSE_INIT << 24 */
		};

		enum fuse_notify_code {