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>
This commit is contained in:
Michael S. Tsirkin 2019-09-04 08:36:33 -04:00 committed by Miklos Szeredi
parent 15c8e72e88
commit 501ae8ecae
1 changed files with 4 additions and 0 deletions

View File

@ -425,6 +425,10 @@ enum fuse_opcode {
/* CUSE specific operations */ /* CUSE specific operations */
CUSE_INIT = 4096, 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 { enum fuse_notify_code {