nfsd: don't support msnfs export option

We've long had these pointless #ifdef MSNFS's sprinkled throughout the
code--pointless because MSNFS is always defined (and we give no config
option to make that easy to change).  So we could just remove the
ifdef's and compile the resulting code unconditionally.

But as long as we're there: why not just rip out this code entirely?
The only purpose is to implement the "msnfs" export option which turns
on Windows-like behavior in some cases, and:

	- the export option isn't documented anywhere;
	- the userland utilities (which would need to be able to parse
	  "msnfs" in an export file) don't support it;
	- I don't know how to maintain this, as I don't know what the
	  proper behavior is; and
	- google shows no evidence that anyone has ever used this.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/export.c

-#define MSNFS	/* HACK HACK */
 /*
  * NFS exporting and validation.
  *
@@ -1444,9 +1443,6 @@ static struct flags {
 	{ NFSEXP_NOSUBTREECHECK, {"no_subtree_check", ""}},
 	{ NFSEXP_NOAUTHNLM, {"insecure_locks", ""}},
 	{ NFSEXP_V4ROOT, {"v4root", ""}},
-#ifdef MSNFS
-	{ NFSEXP_MSNFS, {"msnfs", ""}},
-#endif
 	{ 0, {"", ""}}
 };
 

fs/nfsd/vfs.c

-#define MSNFS	/* HACK HACK */
 /*
  * File operations used by nfsd. Some of these have been ripped from
  * other parts of the kernel because they weren't exported, others
@@ -875,15 +874,6 @@ static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
 	return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
 }
 
-static inline int svc_msnfs(struct svc_fh *ffhp)
-{
-#ifdef MSNFS
-	return (ffhp->fh_export->ex_flags & NFSEXP_MSNFS);
-#else
-	return 0;
-#endif
-}
-
 static __be32
 nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
               loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
@@ -896,9 +886,6 @@ nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	err = nfserr_perm;
 	inode = file->f_path.dentry->d_inode;
 
-	if (svc_msnfs(fhp) && !lock_may_read(inode, offset, *count))
-		goto out;
-
 	if (file->f_op->splice_read && rqstp->rq_splice_ok) {
 		struct splice_desc sd = {
 			.len		= 0,
@@ -923,7 +910,6 @@ nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 		fsnotify_access(file);
 	} else 
 		err = nfserrno(host_err);
-out:
 	return err;
 }
 
@@ -988,14 +974,6 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	int			stable = *stablep;
 	int			use_wgather;
 
-#ifdef MSNFS
-	err = nfserr_perm;
-
-	if ((fhp->fh_export->ex_flags & NFSEXP_MSNFS) &&
-		(!lock_may_write(file->f_path.dentry->d_inode, offset, *cnt)))
-		goto out;
-#endif
-
 	dentry = file->f_path.dentry;
 	inode = dentry->d_inode;
 	exp   = fhp->fh_export;
@@ -1046,7 +1024,6 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 		err = 0;
 	else
 		err = nfserrno(host_err);
-out:
 	return err;
 }
 
@@ -1751,13 +1728,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
 	if (ndentry == trap)
 		goto out_dput_new;
 
-	if (svc_msnfs(ffhp) &&
-		((atomic_read(&odentry->d_count) > 1)
-		 || (atomic_read(&ndentry->d_count) > 1))) {
-			host_err = -EPERM;
-			goto out_dput_new;
-	}
-
 	host_err = -EXDEV;
 	if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
 		goto out_dput_new;
@@ -1836,17 +1806,10 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 	if (host_err)
 		goto out_nfserr;
 
-	if (type != S_IFDIR) { /* It's UNLINK */
-#ifdef MSNFS
-		if ((fhp->fh_export->ex_flags & NFSEXP_MSNFS) &&
-			(atomic_read(&rdentry->d_count) > 1)) {
-			host_err = -EPERM;
-		} else
-#endif
+	if (type != S_IFDIR)
 		host_err = vfs_unlink(dirp, rdentry);
-	} else { /* It's RMDIR */
+	else
 		host_err = vfs_rmdir(dirp, rdentry);
-	}
 
 	dput(rdentry);
 

include/linux/nfsd/export.h

@@ -35,7 +35,7 @@
 #define NFSEXP_NOHIDE		0x0200
 #define NFSEXP_NOSUBTREECHECK	0x0400
 #define	NFSEXP_NOAUTHNLM	0x0800		/* Don't authenticate NLM requests - just trust */
-#define NFSEXP_MSNFS		0x1000	/* do silly things that MS clients expect */
+#define NFSEXP_MSNFS		0x1000	/* do silly things that MS clients expect; no longer supported */
 #define NFSEXP_FSID		0x2000
 #define	NFSEXP_CROSSMOUNT	0x4000
 #define	NFSEXP_NOACL		0x8000	/* reserved for possible ACL related use */