[PATCH v3 08/17] nfsd: nfsd4_create_file(): Move NFSD_MAY_CREATE check earlier

[NeilBrown <neilb@ownmail.net>]

From: NeilBrown <neil@brown.name>

We only need NFS_MAY_CREATE check if the file doesn't exist, but it is
nfsd-specific code as it needs to check NFSEXP_READONLY and I want that
to be separate from vfs-specific code, which eventually all be provided
by the VFS.

So move that check earlier, but hold the error status until needed.

The if/else chain here looks a bit clumsy, but it will make a later
patch cleaner.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
---
 fs/nfsd/nfs4proc.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 83ad690a4948..33c112eda4c4 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -260,7 +260,7 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	struct dentry *parent, *child = ERR_PTR(-EINVAL);
 	__u32 v_mtime, v_atime;
 	struct inode *inode;
-	__be32 status;
+	__be32 status, create_status;
 	int host_err;
 
 	if (name_is_dot_dotdot(open->op_fname, open->op_fnamelen))
@@ -349,6 +349,8 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		iap->ia_atime.tv_nsec = 0;
 	}
 
+	create_status = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
+
 	host_err = fh_want_write(fhp);
 	if (host_err) {
 		status = nfserrno(host_err);
@@ -362,16 +364,17 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		goto out;
 	}
 
-	if (d_really_is_negative(child)) {
-		status = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
-		if (status != nfs_ok)
-			goto out;
-
+	if (d_really_is_positive(child)) {
+		/* No creation needed */
+	} else if (create_status) {
+		status = create_status;
+	} else {
 		status = nfsd4_vfs_create(fhp, &child, open);
-		if (status != nfs_ok)
-			goto out;
-		open->op_created = open->op_filp->f_mode & FMODE_CREATED;
+		if (status == nfs_ok)
+			open->op_created = open->op_filp->f_mode & FMODE_CREATED;
 	}
+	if (status != nfs_ok)
+		goto out;
 
 	status = fh_compose(resfhp, fhp->fh_export, child, fhp);
 	if (status != nfs_ok)
-- 
2.50.0.107.gf914562f5916.dirty