[PATCH 17/18] nfsd: use vfs_lookup_open() for non-creating open requests too.

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

Now that we use vfs_lookup_open() for creating open requests, we can use
for non-creating too as vfs_lookup_open() is already able to do that.

This means that when exporting NFS, the lookup and open can be combined
using ->atomic_open.

The resulting simplification allows fh_fill_pre_attrs() to be moved into
nfsd4_open_file() (renamed from nfsd4_create_file()) so it is closer to
fh_full_post_attrs and fh_fill_post_noop calls.

As ->op_create_mode isn't defined when op_create is zero, we need a
local create_mode which is -1 (illegal value) when op_create is zero.

Signed-off-by: NeilBrown <neil-+NVA1uvv1dVBDLzU/[email protected]>
---
 fs/nfsd/nfs4proc.c | 97 +++++++++++++++++++++++-----------------------
 1 file changed, 48 insertions(+), 49 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 61ecd4123817..19a2d3446ae3 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -201,30 +201,30 @@ static inline bool nfsd4_create_is_exclusive(int createmode)
 		createmode == NFS4_CREATE_EXCLUSIVE4_1;
 }
 
-
 /*
- * Implement NFSv4's unchecked, guarded, and exclusive create
- * semantics for regular files. Open state for this new file is
- * subsequently fabricated in nfsd4_process_open2().
- *
+ * Implement NFSv4's open semantics for regular files.
+ * Both create (unchecked, guarded, and exclusive) and non-create.
+ * Open state for this new file is subsequently fabricated in
+ * nfsd4_process_open2().
  * Upon return, caller must release @fhp and @resfhp.
  */
 static __be32
-nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
-		  struct svc_fh *resfhp, struct nfsd4_open *open)
+nfsd4_open_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
+		struct svc_fh *resfhp, struct nfsd4_open *open)
 {
 	struct iattr *iap = &open->op_iattr;
 	struct nfsd_attrs attrs = {
 		.na_iattr	= iap,
 		.na_seclabel	= &open->op_label,
 	};
-	int oflags = O_CREAT | O_LARGEFILE;
+	int oflags = O_LARGEFILE;
 	struct dentry *child = ERR_PTR(-EINVAL);
 	struct path parent = {
 		.mnt = fhp->fh_export->ex_path.mnt,
 		.dentry = fhp->fh_dentry,
 	};
 	__u32 v_mtime, v_atime;
+	int createmode = -1;
 	__be32 status;
 
 	if (isdotent(open->op_fname, open->op_fnamelen))
@@ -236,6 +236,10 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	if (status != nfs_ok)
 		return status;
 
+	status = fh_fill_pre_attrs(fhp);
+	if (status)
+		return status;
+
 	if (!IS_POSIXACL(d_inode(parent.dentry)))
 		iap->ia_mode &= ~current_umask();
 
@@ -258,13 +262,18 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		open->op_pacl = NULL;
 	}
 
+	if (open->op_create) {
+		createmode = open->op_createmode;
+		oflags |= O_CREAT;
+	}
+
 	/* A newly created file already has a file size of zero. */
 	if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
 		iap->ia_valid &= ~ATTR_SIZE;
 
 	v_mtime = 0;
 	v_atime = 0;
-	if (nfsd4_create_is_exclusive(open->op_createmode)) {
+	if (nfsd4_create_is_exclusive(createmode)) {
 		u32 *verifier = (u32 *)open->op_verf.data;
 
 		/*
@@ -288,7 +297,7 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	/* Only ask the fs to provide exclusive-create if we aren't using
 	 * the NFS verifier to do it outselves.
 	 */
-	if (open->op_createmode == NFS4_CREATE_GUARDED)
+	if (createmode == NFS4_CREATE_GUARDED)
 		oflags |= O_EXCL;
 
 	switch (open->op_share_access & NFS4_SHARE_ACCESS_BOTH) {
@@ -321,14 +330,14 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		goto out;
 
 	if (!open->op_created &&
-	    nfsd4_create_is_exclusive(open->op_createmode) &&
+	    nfsd4_create_is_exclusive(createmode) &&
 	    inode_get_mtime_sec(d_inode(child)) == v_mtime &&
 	    inode_get_atime_sec(d_inode(child)) == v_atime &&
 	    d_inode(child)->i_size == 0)
 		open->op_created = true;
 
 	if (!open->op_created &&
-	    open->op_createmode == NFS4_CREATE_UNCHECKED) {
+	    createmode == NFS4_CREATE_UNCHECKED) {
 		/* NFSv4 protocol requires change attributes
 		 * even though no change happened.
 		 */
@@ -429,45 +438,35 @@ do_open_lookup(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, stru
 	fh_init(*resfh, NFS4_FHSIZE);
 	open->op_truncate = false;
 
-	status = fh_fill_pre_attrs(current_fh);
-	if (status)
-		goto out;
-	if (open->op_create) {
-		/* FIXME: check session persistence and pnfs flags.
-		 * The nfsv4.1 spec requires the following semantics:
-		 *
-		 * Persistent   | pNFS   | Server REQUIRED | Client Allowed
-		 * Reply Cache  | server |                 |
-		 * -------------+--------+-----------------+--------------------
-		 * no           | no     | EXCLUSIVE4_1    | EXCLUSIVE4_1
-		 *              |        |                 | (SHOULD)
-		 *              |        | and EXCLUSIVE4  | or EXCLUSIVE4
-		 *              |        |                 | (SHOULD NOT)
-		 * no           | yes    | EXCLUSIVE4_1    | EXCLUSIVE4_1
-		 * yes          | no     | GUARDED4        | GUARDED4
-		 * yes          | yes    | GUARDED4        | GUARDED4
-		 */
+	/* FIXME: check session persistence and pnfs flags.
+	 * The nfsv4.1 spec requires the following semantics:
+	 *
+	 * Persistent   | pNFS   | Server REQUIRED | Client Allowed
+	 * Reply Cache  | server |                 |
+	 * -------------+--------+-----------------+--------------------
+	 * no           | no     | EXCLUSIVE4_1    | EXCLUSIVE4_1
+	 *              |        |                 | (SHOULD)
+	 *              |        | and EXCLUSIVE4  | or EXCLUSIVE4
+	 *              |        |                 | (SHOULD NOT)
+	 * no           | yes    | EXCLUSIVE4_1    | EXCLUSIVE4_1
+	 * yes          | no     | GUARDED4        | GUARDED4
+	 * yes          | yes    | GUARDED4        | GUARDED4
+	 */
 
-		current->fs->umask = open->op_umask;
-		status = nfsd4_create_file(rqstp, current_fh, *resfh, open);
-		current->fs->umask = 0;
+	current->fs->umask = open->op_umask;
+	status = nfsd4_open_file(rqstp, current_fh, *resfh, open);
+	current->fs->umask = 0;
+
+	/*
+	 * Following rfc 3530 14.2.16, and rfc 5661 18.16.4
+	 * use the returned bitmask to indicate which attributes
+	 * we used to store the verifier:
+	 */
+	if (open->op_create && status == 0 &&
+	    nfsd4_create_is_exclusive(open->op_createmode))
+		open->op_bmval[1] |= (FATTR4_WORD1_TIME_ACCESS |
+				      FATTR4_WORD1_TIME_MODIFY);
 
-		/*
-		 * Following rfc 3530 14.2.16, and rfc 5661 18.16.4
-		 * use the returned bitmask to indicate which attributes
-		 * we used to store the verifier:
-		 */
-		if (nfsd4_create_is_exclusive(open->op_createmode) && status == 0)
-			open->op_bmval[1] |= (FATTR4_WORD1_TIME_ACCESS |
-						FATTR4_WORD1_TIME_MODIFY);
-	} else {
-		status = nfsd_lookup(rqstp, current_fh,
-				     open->op_fname, open->op_fnamelen, *resfh);
-		/* NFSv4 protocol requires change attributes even though
-		 * no change happened.
-		 */
-		fh_fill_post_noop(current_fh);
-	}
 	if (status)
 		goto out;
 	status = nfsd_check_obj_isreg(*resfh, cstate->minorversion);
-- 
2.50.0.107.gf914562f5916.dirty