[PATCH] kNFSd: NFSv4: tweak nfsd_readdir() for NFSv4

This patch makes three small changes to nfsd_readdir().

First, the 'filldir' routine for NFSv4 may return an arbitrary error,
which should become the return value for nfsd_readdir().  I implemented
this by adding an 'nfserr' field to the 'struct readdir_cd'.

Second, in NFSv4 the caller of nfsd_readdir() will specify an attribute
bitmap, which must be communicated to the 'filldir' routine.  I implemented
this by adding a @bitmap parameter to nfsd_readdir() and a corresponding
field in the 'struct readdir_cd'.  (The bitmap is not interpreted in any
way by nfsd_readdir().)

Finally, NFSv4 defines a new error nfserr_readdir_nospc, which indicates
that there was not enough buffer space to encode a single entry.

fs/nfsd/nfs3proc.c

@@ -460,7 +460,7 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp, struct nfsd3_readdirargs *argp,
 	fh_copy(&resp->fh, &argp->fh);
 	nfserr = nfsd_readdir(rqstp, &resp->fh, (loff_t) argp->cookie, 
 					nfs3svc_encode_entry,
-					buffer, &count, argp->verf);
+					buffer, &count, argp->verf, NULL);
 	memcpy(resp->verf, argp->verf, 8);
 	resp->count = count;
 
@@ -495,7 +495,7 @@ nfsd3_proc_readdirplus(struct svc_rqst *rqstp, struct nfsd3_readdirargs *argp,
 	fh_copy(&resp->fh, &argp->fh);
 	nfserr = nfsd_readdir(rqstp, &resp->fh, (loff_t) argp->cookie, 
 					nfs3svc_encode_entry_plus,
-					buffer, &count, argp->verf);
+					buffer, &count, argp->verf, NULL);
 	memcpy(resp->verf, argp->verf, 8);
 	resp->count = count;
 

fs/nfsd/nfsproc.c

@@ -492,7 +492,7 @@ nfsd_proc_readdir(struct svc_rqst *rqstp, struct nfsd_readdirargs *argp,
 	/* Read directory and encode entries on the fly */
 	nfserr = nfsd_readdir(rqstp, &argp->fh, (loff_t) argp->cookie, 
 			      nfssvc_encode_entry,
-			      buffer, &count, NULL);
+			      buffer, &count, NULL, NULL);
 	resp->count = count;
 
 	fh_put(&argp->fh);

fs/nfsd/vfs.c

@@ -1381,7 +1381,7 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
  */
 int
 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, 
-             encode_dent_fn func, u32 *buffer, int *countp, u32 *verf)
+             encode_dent_fn func, u32 *buffer, int *countp, u32 *verf, u32 *bmval)
 {
 	u32		*p;
 	int		oldlen, eof, err;
@@ -1402,6 +1402,10 @@ nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
 	cd.buffer = buffer;
 	cd.buflen = *countp; /* count of words */
 	cd.dirfh  = fhp;
+	if (bmval) {
+		cd.bmval[0] = bmval[0];
+		cd.bmval[1] = bmval[1];
+	}
 
 	/*
 	 * Read the directory entries. This silly loop is necessary because
@@ -1417,8 +1421,15 @@ nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
 		if (err < 0)
 			goto out_nfserr;
 
+		err = cd.nfserr;
+		if (err)
+			goto out_close;
 	} while (oldlen != cd.buflen && !cd.eob);
 
+	err = nfserr_readdir_nospc;
+	if (rqstp->rq_vers == 4 && cd.eob && cd.buffer == buffer)
+		goto out_close;
+
 	/* If we didn't fill the buffer completely, we're at EOF */
 	eof = !cd.eob;
 

include/linux/nfsd/nfsd.h

@@ -55,6 +55,8 @@ struct readdir_cd {
 	char			plus;		/* readdirplus */
 	char			eob;		/* end of buffer */
 	char			dotonly;
+	int			nfserr;		/* v4 only */
+	u32			bmval[2];	/* v4 only */
 };
 typedef int		(*encode_dent_fn)(struct readdir_cd *, const char *,
 						int, loff_t, ino_t, unsigned int);
@@ -119,7 +121,8 @@ int		nfsd_truncate(struct svc_rqst *, struct svc_fh *,
 				unsigned long size);
 int		nfsd_readdir(struct svc_rqst *, struct svc_fh *,
 				loff_t, encode_dent_fn,
-				u32 *buffer, int *countp, u32 *verf);
+				u32 *buffer, int *countp, u32 *verf,
+				u32 *bmval);
 int		nfsd_statfs(struct svc_rqst *, struct svc_fh *,
 				struct statfs *);