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NFSD: da_addr_body field missing in some GETDEVICEINFO replies

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[ 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>
This commit is contained in:
Chuck Lever 2023-08-16 10:20:52 -04:00 committed by Greg Kroah-Hartman
parent b0f127a7c6
commit 19a648a075
3 changed files with 29 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
fs/nfsd/blocklayoutxdr.c
View File

@ -82,6 +82,15 @@ nfsd4_block_encode_getdeviceinfo(struct xdr_stream *xdr,
int len = sizeof(__be32), ret, i;
__be32 *p;
/*
* See paragraph 5 of RFC 8881 S18.40.3.
*/
if (!gdp->gd_maxcount) {
if (xdr_stream_encode_u32(xdr, 0) != XDR_UNIT)
return nfserr_resource;
return nfs_ok;
}
p = xdr_reserve_space(xdr, len + sizeof(__be32));
if (!p)
return nfserr_resource;

9
fs/nfsd/flexfilelayoutxdr.c
View File

@ -85,6 +85,15 @@ nfsd4_ff_encode_getdeviceinfo(struct xdr_stream *xdr,
int addr_len;
__be32 *p;
/*
* See paragraph 5 of RFC 8881 S18.40.3.
*/
if (!gdp->gd_maxcount) {
if (xdr_stream_encode_u32(xdr, 0) != XDR_UNIT)
return nfserr_resource;
return nfs_ok;
}
/* len + padding for two strings */
addr_len = 16 + da->netaddr.netid_len + da->netaddr.addr_len;
ver_len = 20;

25
fs/nfsd/nfs4xdr.c
View File

@ -4533,20 +4533,17 @@ nfsd4_encode_getdeviceinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
*p++ = cpu_to_be32(gdev->gd_layout_type);
/* If maxcount is 0 then just update notifications */
if (gdev->gd_maxcount != 0) {
ops = nfsd4_layout_ops[gdev->gd_layout_type];
nfserr = ops->encode_getdeviceinfo(xdr, gdev);
if (nfserr) {
/*
* We don't bother to burden the layout drivers with
* enforcing gd_maxcount, just tell the client to
* come back with a bigger buffer if it's not enough.
*/
if (xdr->buf->len + 4 > gdev->gd_maxcount)
goto toosmall;
return nfserr;
}
ops = nfsd4_layout_ops[gdev->gd_layout_type];
nfserr = ops->encode_getdeviceinfo(xdr, gdev);
if (nfserr) {
/*
* We don't bother to burden the layout drivers with
* enforcing gd_maxcount, just tell the client to
* come back with a bigger buffer if it's not enough.
*/
if (xdr->buf->len + 4 > gdev->gd_maxcount)
goto toosmall;
return nfserr;
}
if (gdev->gd_notify_types) {