[PATCH] NFSv4: Client-side xdr for reading NFSv4 acls

 Client-side support for NFSv4 acls: xdr encoding and decoding routines for
 reading acls

 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 108 insertions, 0 deletions

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 8204926bb467..6f1c003ee33a 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -365,6 +365,13 @@ static int nfs_stat_to_errno(int);
                                 encode_delegreturn_maxsz)
 #define NFS4_dec_delegreturn_sz (compound_decode_hdr_maxsz + \
                                 decode_delegreturn_maxsz)
+#define NFS4_enc_getacl_sz      (compound_encode_hdr_maxsz + \
+                                encode_putfh_maxsz + \
+                                encode_getattr_maxsz)
+#define NFS4_dec_getacl_sz      (compound_decode_hdr_maxsz + \
+                                decode_putfh_maxsz + \
+                                op_decode_hdr_maxsz + \
+                                nfs4_fattr_bitmap_maxsz + 1)
 
 static struct {
         unsigned int    mode;
@@ -1632,6 +1639,34 @@ out:
 }
 
 /*
+ * Encode a GETACL request
+ */
+static int
+nfs4_xdr_enc_getacl(struct rpc_rqst *req, uint32_t *p,
+                struct nfs_getaclargs *args)
+{
+        struct xdr_stream xdr;
+        struct rpc_auth *auth = req->rq_task->tk_auth;
+        struct compound_hdr hdr = {
+                .nops   = 2,
+        };
+        int replen, status;
+
+        xdr_init_encode(&xdr, &req->rq_snd_buf, p);
+        encode_compound_hdr(&xdr, &hdr);
+        status = encode_putfh(&xdr, args->fh);
+        if (status)
+                goto out;
+        status = encode_getattr_two(&xdr, FATTR4_WORD0_ACL, 0);
+        /* set up reply buffer: */
+        replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS4_dec_getacl_sz) << 2;
+        xdr_inline_pages(&req->rq_rcv_buf, replen,
+                args->acl_pages, args->acl_pgbase, args->acl_len);
+out:
+        return status;
+}
+
+/*
  * Encode a WRITE request
  */
 static int nfs4_xdr_enc_write(struct rpc_rqst *req, uint32_t *p, struct nfs_writeargs *args)
@@ -3125,6 +3160,47 @@ static int decode_renew(struct xdr_stream *xdr)
         return decode_op_hdr(xdr, OP_RENEW);
 }
 
+static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
+                size_t *acl_len)
+{
+        uint32_t *savep;
+        uint32_t attrlen,
+                 bitmap[2] = {0};
+        struct kvec *iov = req->rq_rcv_buf.head;
+        int status;
+
+        *acl_len = 0;
+        if ((status = decode_op_hdr(xdr, OP_GETATTR)) != 0)
+                goto out;
+        if ((status = decode_attr_bitmap(xdr, bitmap)) != 0)
+                goto out;
+        if ((status = decode_attr_length(xdr, &attrlen, &savep)) != 0)
+                goto out;
+
+        if (unlikely(bitmap[0] & (FATTR4_WORD0_ACL - 1U)))
+                return -EIO;
+        if (likely(bitmap[0] & FATTR4_WORD0_ACL)) {
+                int hdrlen, recvd;
+
+                /* We ignore &savep and don't do consistency checks on
+                 * the attr length.  Let userspace figure it out.... */
+                hdrlen = (u8 *)xdr->p - (u8 *)iov->iov_base;
+                recvd = req->rq_rcv_buf.len - hdrlen;
+                if (attrlen > recvd) {
+                        printk(KERN_WARNING "NFS: server cheating in getattr"
+                                        " acl reply: attrlen %u > recvd %u\n",
+                                        attrlen, recvd);
+                        return -EINVAL;
+                }
+                if (attrlen <= *acl_len)
+                        xdr_read_pages(xdr, attrlen);
+                *acl_len = attrlen;
+        }
+
+out:
+        return status;
+}
+
 static int
 decode_savefh(struct xdr_stream *xdr)
 {
@@ -3418,6 +3494,29 @@ out:
 
 
 /*
+ * Decode GETACL response
+ */
+static int
+nfs4_xdr_dec_getacl(struct rpc_rqst *rqstp, uint32_t *p, size_t *acl_len)
+{
+        struct xdr_stream xdr;
+        struct compound_hdr hdr;
+        int status;
+
+        xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
+        status = decode_compound_hdr(&xdr, &hdr);
+        if (status)
+                goto out;
+        status = decode_putfh(&xdr);
+        if (status)
+                goto out;
+        status = decode_getacl(&xdr, rqstp, acl_len);
+
+out:
+        return status;
+}
+
+/*
  * Decode CLOSE response
  */
 static int nfs4_xdr_dec_close(struct rpc_rqst *rqstp, uint32_t *p, struct nfs_closeres *res)
@@ -4017,6 +4116,7 @@ struct rpc_procinfo	nfs4_procedures[] = {
   PROC(READDIR,         enc_readdir,    dec_readdir),
   PROC(SERVER_CAPS,     enc_server_caps, dec_server_caps),
   PROC(DELEGRETURN,     enc_delegreturn, dec_delegreturn),
+  PROC(GETACL,          enc_getacl,     dec_getacl),
 };
 
 struct rpc_version              nfs_version4 = {
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index 5ca8a8d8ccdf..6ee7e2585af5 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -382,6 +382,7 @@ enum {
         NFSPROC4_CLNT_READDIR,
         NFSPROC4_CLNT_SERVER_CAPS,
         NFSPROC4_CLNT_DELEGRETURN,
+        NFSPROC4_CLNT_GETACL,
 };
 
 #endif
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index cf38db59f347..9f5e1d407c7b 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -326,6 +326,13 @@ struct nfs_setattrargs {
         const u32 *                     bitmask;
 };
 
+struct nfs_getaclargs {
+        struct nfs_fh *                 fh;
+        size_t                          acl_len;
+        unsigned int                    acl_pgbase;
+        struct page **                  acl_pages;
+};
+
 struct nfs_setattrres {
         struct nfs_fattr *              fattr;
         const struct nfs_server *       server;