[PATCH] nfsd4: don't reopen for delegated client

We don't really need to be doing a separate open for every stateid.  And in
the case of an open from a client that already has a delegation on a file, it
unnecessarily results in a delegation recall.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/nfsd/nfs4state.c

@@ -1547,6 +1547,24 @@ find_delegation_file(struct nfs4_file *fp, stateid_t *stid)
 	return NULL;
 }
 
+static void
+nfs4_check_deleg(struct nfs4_file *fp, struct nfsd4_open *open,
+		struct nfs4_delegation **dp)
+{
+	int flags;
+	int status;
+
+	*dp = find_delegation_file(fp, &open->op_delegate_stateid);
+	if (*dp == NULL)
+		return;
+	flags = open->op_share_access == NFS4_SHARE_ACCESS_READ ?
+						RD_STATE : WR_STATE;
+	status = nfs4_check_delegmode(*dp, flags);
+	if (status)
+		*dp = NULL;
+	return;
+}
+
 static int
 nfs4_check_open(struct nfs4_file *fp, struct nfsd4_open *open, struct nfs4_stateid **stpp)
 {
@@ -1572,22 +1590,29 @@ nfs4_check_open(struct nfs4_file *fp, struct nfsd4_open *open, struct nfs4_state
 
 static int
 nfs4_new_open(struct svc_rqst *rqstp, struct nfs4_stateid **stpp,
+		struct nfs4_delegation *dp,
 		struct svc_fh *cur_fh, int flags)
 {
 	struct nfs4_stateid *stp;
-	int status;
 
 	stp = kmalloc(sizeof(struct nfs4_stateid), GFP_KERNEL);
 	if (stp == NULL)
 		return nfserr_resource;
 
-	status = nfsd_open(rqstp, cur_fh, S_IFREG, flags, &stp->st_vfs_file);
+	if (dp) {
+		get_file(dp->dl_vfs_file);
+		stp->st_vfs_file = dp->dl_vfs_file;
+	} else {
+		int status;
+		status = nfsd_open(rqstp, cur_fh, S_IFREG, flags,
+				&stp->st_vfs_file);
 		if (status) {
 			if (status == nfserr_dropit)
 				status = nfserr_jukebox;
 			kfree(stp);
 			return status;
 		}
+	}
 	vfsopen++;
 	*stpp = stp;
 	return 0;
@@ -1720,6 +1745,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
 	struct nfs4_file *fp = NULL;
 	struct inode *ino = current_fh->fh_dentry->d_inode;
 	struct nfs4_stateid *stp = NULL;
+	struct nfs4_delegation *dp = NULL;
 	int status;
 
 	status = nfserr_inval;
@@ -1734,6 +1760,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
 	if (fp) {
 		if ((status = nfs4_check_open(fp, open, &stp)))
 			goto out;
+		nfs4_check_deleg(fp, open, &dp);
 	} else {
 		status = nfserr_resource;
 		fp = alloc_init_file(ino);
@@ -1757,7 +1784,8 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
 			flags = MAY_WRITE;
 		else
 			flags = MAY_READ;
-		if ((status = nfs4_new_open(rqstp, &stp, current_fh, flags)))
+		status = nfs4_new_open(rqstp, &stp, dp, current_fh, flags);
+		if (status)
 			goto out;
 		init_stateid(stp, fp, open);
 		status = nfsd4_truncate(rqstp, current_fh, open);