nfsd: make V4ROOT exports read-only

I can't see any use for writeable V4ROOT exports.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 18ac20ffedd2ead4a13dac744d1c605f6f4c8bb7..7d5ba1b0ffcf240ffd868e8e0a305c144691da24 100644 (file)
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -355,7 +355,7 @@ 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)
 {
 
        /*
@@ -367,6 +367,13 @@ static int check_export(struct inode *inode, int flags, unsigned char *uuid)
            !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)
@@ -375,7 +382,7 @@ 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;
@@ -590,7 +597,7 @@ 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;
@@ -1029,7 +1036,7 @@ 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;