nfsd41: create_session operation

Implement the create_session operation confoming to
http://tools.ietf.org/html/draft-ietf-nfsv4-minorversion1-26

Look up the client id (generated by the server on exchange_id,
given by the client on create_session).
If neither a confirmed or unconfirmed client is found
then the client id is stale
If a confirmed cilent is found (i.e. we already received
create_session for it) then compare the sequence id
to determine if it's a replay or possibly a mis-ordered rpc.
If the seqid is in order, update the confirmed client seqid
and procedd with updating the session parameters.

If an unconfirmed client_id is found then verify the creds
and seqid.  If both match move the client id to confirmed state
and proceed with processing the create_session.

Currently, we do not support persistent sessions, and RDMA.

alloc_init_session generates a new sessionid and creates
a session structure.

NFSD_PAGES_PER_SLOT is used for the max response cached calculation, and for
the counting of DRC pages using the hard limits set in struct srv_serv.

A note on NFSD_PAGES_PER_SLOT:

Other patches in this series allow for NFSD_PAGES_PER_SLOT + 1 pages to be
cached in a DRC slot when the response size is less than NFSD_PAGES_PER_SLOT *
PAGE_SIZE but xdr_buf pages are used. e.g. a READDIR operation will encode a
small amount of data in the xdr_buf head, and then the READDIR in the xdr_buf
pages.  So, the hard limit calculation use of pages by a session is
underestimated by the number of cached operations using the xdr_buf pages.

Yet another patch caches no pages for the solo sequence operation, or any
compound where cache_this is False.  So the hard limit calculation use of
pages by a session is overestimated by the number of these operations in the
cache.

TODO: improve resource pre-allocation and negotiate session
parameters accordingly.  Respect and possibly adjust
backchannel attributes.

Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: Dean Hildebrand <dhildeb@us.ibm.com>
[nfsd41: remove headerpadsz from channel attributes]
Our client and server only support a headerpadsz of 0.
[nfsd41: use DRC limits in fore channel init]
[nfsd41: do not change CREATE_SESSION back channel attrs]
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[use sessionid_lock spin lock]
[nfsd41: use bool inuse for slot state]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfsd41 remove sl_session from alloc_init_session]
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[simplify nfsd4_encode_create_session error handling]
[nfsd41: fix comment style in init_forechannel_attrs]
[nfsd41: allocate struct nfsd4_session and slot table in one piece]
[nfsd41: no need to INIT_LIST_HEAD in alloc_init_session just prior to list_add]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 145 insertions, 3 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 09415bcf078e..671f9b96429b 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1099,7 +1099,108 @@ static __be32
 nfsd4_decode_create_session(struct nfsd4_compoundargs *argp,
 			    struct nfsd4_create_session *sess)
 {
-	return nfserr_opnotsupp;	/* stub */
+	DECODE_HEAD;
+
+	u32 dummy;
+	char *machine_name;
+	int i;
+	int nr_secflavs;
+
+	READ_BUF(16);
+	COPYMEM(&sess->clientid, 8);
+	READ32(sess->seqid);
+	READ32(sess->flags);
+
+	/* Fore channel attrs */
+	READ_BUF(28);
+	READ32(dummy); /* headerpadsz is always 0 */
+	READ32(sess->fore_channel.maxreq_sz);
+	READ32(sess->fore_channel.maxresp_sz);
+	READ32(sess->fore_channel.maxresp_cached);
+	READ32(sess->fore_channel.maxops);
+	READ32(sess->fore_channel.maxreqs);
+	READ32(sess->fore_channel.nr_rdma_attrs);
+	if (sess->fore_channel.nr_rdma_attrs == 1) {
+		READ_BUF(4);
+		READ32(sess->fore_channel.rdma_attrs);
+	} else if (sess->fore_channel.nr_rdma_attrs > 1) {
+		dprintk("Too many fore channel attr bitmaps!\n");
+		goto xdr_error;
+	}
+
+	/* Back channel attrs */
+	READ_BUF(28);
+	READ32(dummy); /* headerpadsz is always 0 */
+	READ32(sess->back_channel.maxreq_sz);
+	READ32(sess->back_channel.maxresp_sz);
+	READ32(sess->back_channel.maxresp_cached);
+	READ32(sess->back_channel.maxops);
+	READ32(sess->back_channel.maxreqs);
+	READ32(sess->back_channel.nr_rdma_attrs);
+	if (sess->back_channel.nr_rdma_attrs == 1) {
+		READ_BUF(4);
+		READ32(sess->back_channel.rdma_attrs);
+	} else if (sess->back_channel.nr_rdma_attrs > 1) {
+		dprintk("Too many back channel attr bitmaps!\n");
+		goto xdr_error;
+	}
+
+	READ_BUF(8);
+	READ32(sess->callback_prog);
+
+	/* callback_sec_params4 */
+	READ32(nr_secflavs);
+	for (i = 0; i < nr_secflavs; ++i) {
+		READ_BUF(4);
+		READ32(dummy);
+		switch (dummy) {
+		case RPC_AUTH_NULL:
+			/* Nothing to read */
+			break;
+		case RPC_AUTH_UNIX:
+			READ_BUF(8);
+			/* stamp */
+			READ32(dummy);
+
+			/* machine name */
+			READ32(dummy);
+			READ_BUF(dummy);
+			SAVEMEM(machine_name, dummy);
+
+			/* uid, gid */
+			READ_BUF(8);
+			READ32(sess->uid);
+			READ32(sess->gid);
+
+			/* more gids */
+			READ_BUF(4);
+			READ32(dummy);
+			READ_BUF(dummy * 4);
+			for (i = 0; i < dummy; ++i)
+				READ32(dummy);
+			break;
+		case RPC_AUTH_GSS:
+			dprintk("RPC_AUTH_GSS callback secflavor "
+				"not supported!\n");
+			READ_BUF(8);
+			/* gcbp_service */
+			READ32(dummy);
+			/* gcbp_handle_from_server */
+			READ32(dummy);
+			READ_BUF(dummy);
+			p += XDR_QUADLEN(dummy);
+			/* gcbp_handle_from_client */
+			READ_BUF(4);
+			READ32(dummy);
+			READ_BUF(dummy);
+			p += XDR_QUADLEN(dummy);
+			break;
+		default:
+			dprintk("Illegal callback secflavor\n");
+			return nfserr_inval;
+		}
+	}
+	DECODE_TAIL;
 }
 
 static __be32
@@ -2821,8 +2922,49 @@ static __be32
 nfsd4_encode_create_session(struct nfsd4_compoundres *resp, int nfserr,
 			    struct nfsd4_create_session *sess)
 {
-	/* stub */
-	return nfserr;
+	ENCODE_HEAD;
+
+	if (nfserr)
+		return nfserr;
+
+	RESERVE_SPACE(24);
+	WRITEMEM(sess->sessionid.data, NFS4_MAX_SESSIONID_LEN);
+	WRITE32(sess->seqid);
+	WRITE32(sess->flags);
+	ADJUST_ARGS();
+
+	RESERVE_SPACE(28);
+	WRITE32(0); /* headerpadsz */
+	WRITE32(sess->fore_channel.maxreq_sz);
+	WRITE32(sess->fore_channel.maxresp_sz);
+	WRITE32(sess->fore_channel.maxresp_cached);
+	WRITE32(sess->fore_channel.maxops);
+	WRITE32(sess->fore_channel.maxreqs);
+	WRITE32(sess->fore_channel.nr_rdma_attrs);
+	ADJUST_ARGS();
+
+	if (sess->fore_channel.nr_rdma_attrs) {
+		RESERVE_SPACE(4);
+		WRITE32(sess->fore_channel.rdma_attrs);
+		ADJUST_ARGS();
+	}
+
+	RESERVE_SPACE(28);
+	WRITE32(0); /* headerpadsz */
+	WRITE32(sess->back_channel.maxreq_sz);
+	WRITE32(sess->back_channel.maxresp_sz);
+	WRITE32(sess->back_channel.maxresp_cached);
+	WRITE32(sess->back_channel.maxops);
+	WRITE32(sess->back_channel.maxreqs);
+	WRITE32(sess->back_channel.nr_rdma_attrs);
+	ADJUST_ARGS();
+
+	if (sess->back_channel.nr_rdma_attrs) {
+		RESERVE_SPACE(4);
+		WRITE32(sess->back_channel.rdma_attrs);
+		ADJUST_ARGS();
+	}
+	return 0;
 }
 
 static __be32