1 files changed, 37 insertions, 28 deletions

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index c1c9e035d4a4..c487810a2366 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -1,7 +1,5 @@
 #define MSNFS   /* HACK HACK */
 /*
- * linux/fs/nfsd/export.c
- *
  * NFS exporting and validation.
  *
  * We maintain a list of clients, each of which has a list of
@@ -14,29 +12,16 @@
  * Copyright (C) 1995, 1996 Olaf Kirch, <okir@monad.swb.de>
  */
 
-#include <linux/unistd.h>
-#include <linux/slab.h>
-#include <linux/stat.h>
-#include <linux/in.h>
-#include <linux/seq_file.h>
-#include <linux/syscalls.h>
-#include <linux/rwsem.h>
-#include <linux/dcache.h>
 #include <linux/namei.h>
-#include <linux/mount.h>
-#include <linux/hash.h>
 #include <linux/module.h>
 #include <linux/exportfs.h>
 
-#include <linux/sunrpc/svc.h>
-#include <linux/nfsd/nfsd.h>
-#include <linux/nfsd/nfsfh.h>
 #include <linux/nfsd/syscall.h>
-#include <linux/lockd/bind.h>
-#include <linux/sunrpc/msg_prot.h>
-#include <linux/sunrpc/gss_api.h>
 #include <net/ipv6.h>
 
+#include "nfsd.h"
+#include "nfsfh.h"
+
 #define NFSDDBG_FACILITY        NFSDDBG_EXPORT
 
 typedef struct auth_domain      svc_client;
@@ -369,16 +354,25 @@ static struct svc_export *svc_export_update(struct svc_export *new,
                                             struct svc_export *old);
 static struct svc_export *svc_export_lookup(struct svc_export *);
 
-static int check_export(struct inode *inode, int flags, unsigned char *uuid)
+static int check_export(struct inode *inode, int *flags, unsigned char *uuid)
 {
 
-        /* We currently export only dirs and regular files.
-         * This is what umountd does.
+        /*
+         * We currently export only dirs, regular files, and (for v4
+         * pseudoroot) symlinks.
          */
         if (!S_ISDIR(inode->i_mode) &&
+            !S_ISLNK(inode->i_mode) &&
             !S_ISREG(inode->i_mode))
                 return -ENOTDIR;
 
+        /*
+         * Mountd should never pass down a writeable V4ROOT export, but,
+         * just to make sure:
+         */
+        if (*flags & NFSEXP_V4ROOT)
+                *flags |= NFSEXP_READONLY;
+
         /* There are two requirements on a filesystem to be exportable.
          * 1:  We must be able to identify the filesystem from a number.
          *       either a device number (so FS_REQUIRES_DEV needed)
@@ -387,7 +381,7 @@ static int check_export(struct inode *inode, int flags, unsigned char *uuid)
          *       This means that s_export_op must be set.
          */
         if (!(inode->i_sb->s_type->fs_flags & FS_REQUIRES_DEV) &&
-            !(flags & NFSEXP_FSID) &&
+            !(*flags & NFSEXP_FSID) &&
             uuid == NULL) {
                 dprintk("exp_export: export of non-dev fs without fsid\n");
                 return -EINVAL;
@@ -602,7 +596,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
                                 goto out4;
                 }
 
-                err = check_export(exp.ex_path.dentry->d_inode, exp.ex_flags,
+                err = check_export(exp.ex_path.dentry->d_inode, &exp.ex_flags,
                                    exp.ex_uuid);
                 if (err)
                         goto out4;
@@ -1041,7 +1035,7 @@ exp_export(struct nfsctl_export *nxp)
                 goto finish;
         }
 
-        err = check_export(path.dentry->d_inode, nxp->ex_flags, NULL);
+        err = check_export(path.dentry->d_inode, &nxp->ex_flags, NULL);
         if (err) goto finish;
 
         err = -ENOMEM;
@@ -1320,6 +1314,23 @@ rqst_exp_parent(struct svc_rqst *rqstp, struct path *path)
         return exp;
 }
 
+static struct svc_export *find_fsidzero_export(struct svc_rqst *rqstp)
+{
+        struct svc_export *exp;
+        u32 fsidv[2];
+
+        mk_fsid(FSID_NUM, fsidv, 0, 0, 0, NULL);
+
+        exp = rqst_exp_find(rqstp, FSID_NUM, fsidv);
+        /*
+         * We shouldn't have accepting an nfsv4 request at all if we
+         * don't have a pseudoexport!:
+         */
+        if (IS_ERR(exp) && PTR_ERR(exp) == -ENOENT)
+                exp = ERR_PTR(-ESERVERFAULT);
+        return exp;
+}
+
 /*
  * Called when we need the filehandle for the root of the pseudofs,
  * for a given NFSv4 client.   The root is defined to be the
@@ -1330,11 +1341,8 @@ exp_pseudoroot(struct svc_rqst *rqstp, struct svc_fh *fhp)
 {
         struct svc_export *exp;
         __be32 rv;
-        u32 fsidv[2];
 
-        mk_fsid(FSID_NUM, fsidv, 0, 0, 0, NULL);
-
-        exp = rqst_exp_find(rqstp, FSID_NUM, fsidv);
+        exp = find_fsidzero_export(rqstp);
         if (IS_ERR(exp))
                 return nfserrno(PTR_ERR(exp));
         rv = fh_compose(fhp, exp, exp->ex_path.dentry, NULL);
@@ -1425,6 +1433,7 @@ static struct flags {
         { NFSEXP_CROSSMOUNT, {"crossmnt", ""}},
         { NFSEXP_NOSUBTREECHECK, {"no_subtree_check", ""}},
         { NFSEXP_NOAUTHNLM, {"insecure_locks", ""}},
+        { NFSEXP_V4ROOT, {"v4root", ""}},
 #ifdef MSNFS
         { NFSEXP_MSNFS, {"msnfs", ""}},
 #endif