[PATCH v2 08/14] nfsd: always open file in nfsd4_create_file()

From: NeilBrown <neil-+NVA1uvv1dVBDLzU/[email protected]>

If the file is found to already exist, open it anyway.  This will
normally be needed eventually anyway, it providing a consistently valid
op_filp will simplify future changes.

Signed-off-by: NeilBrown <neil-+NVA1uvv1dVBDLzU/[email protected]>
---
 fs/nfsd/nfs4proc.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 95e46c15c5a3..244d5f3975b7 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -336,7 +336,30 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	}
 
 	if (d_really_is_positive(child)) {
-		/* No creation needed */
+		/*
+		 * open the file so that we consistently have a valid
+		 * op_filp.
+		 */
+		struct path path = {.mnt = fhp->fh_export->ex_path.mnt,
+				    .dentry = child,
+		};
+		unsigned int oflags = O_LARGEFILE;
+
+		switch (open->op_share_access & NFS4_SHARE_ACCESS_BOTH) {
+		case NFS4_SHARE_ACCESS_WRITE:
+			oflags |= O_WRONLY;
+			break;
+		case NFS4_SHARE_ACCESS_BOTH:
+			oflags |= O_RDWR;
+			break;
+		default:
+			oflags |= O_RDONLY;
+		}
+		open->op_filp = dentry_open(&path, oflags, current_cred());
+		if (IS_ERR(open->op_filp)) {
+			status = nfserrno(PTR_ERR(open->op_filp));
+			open->op_filp = NULL;
+		}
 	} else if (create_status) {
 		status = create_status;
 	} else {
-- 
2.50.0.107.gf914562f5916.dirty