Chuck Lever 16282aeca4 NFSD: da_addr_body field missing in some GETDEVICEINFO replies
[ Upstream commit 6372e2ee629894433fe6107d7048536a3280a284 ]

The XDR specification in RFC 8881 looks like this:

struct device_addr4 {
	layouttype4	da_layout_type;
	opaque		da_addr_body<>;
};

struct GETDEVICEINFO4resok {
	device_addr4	gdir_device_addr;
	bitmap4		gdir_notification;
};

union GETDEVICEINFO4res switch (nfsstat4 gdir_status) {
case NFS4_OK:
	GETDEVICEINFO4resok gdir_resok4;
case NFS4ERR_TOOSMALL:
	count4		gdir_mincount;
default:
	void;
};

Looking at nfsd4_encode_getdeviceinfo() ....

When the client provides a zero gd_maxcount, then the Linux NFS
server implementation encodes the da_layout_type field and then
skips the da_addr_body field completely, proceeding directly to
encode gdir_notification field.

There does not appear to be an option in the specification to skip
encoding da_addr_body. Moreover, Section 18.40.3 says:

> If the client wants to just update or turn off notifications, it
> MAY send a GETDEVICEINFO operation with gdia_maxcount set to zero.
> In that event, if the device ID is valid, the reply's da_addr_body
> field of the gdir_device_addr field will be of zero length.

Since the layout drivers are responsible for encoding the
da_addr_body field, put this fix inside the ->encode_getdeviceinfo
methods.

Fixes: 9cf514ccfacb ("nfsd: implement pNFS operations")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Tom Haynes <loghyr@gmail.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-23 10:59:48 +02:00
..
2023-06-21 15:44:12 +02:00
2023-08-11 11:53:59 +02:00
2021-09-22 12:26:25 +02:00
2022-06-14 18:11:36 +02:00
2023-07-27 08:37:06 +02:00
2023-02-22 12:50:35 +01:00
2022-06-14 18:11:41 +02:00
2020-10-01 13:17:19 +02:00
2023-01-18 11:41:44 +01:00