1 files changed, 311 insertions, 0 deletions

diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
new file mode 100644
index 000000000000..76b08ae9ed82
--- /dev/null
+++ b/fs/nfs/getroot.c
@@ -0,0 +1,311 @@
+/* getroot.c: get the root dentry for an NFS mount
+ *
+ * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/unistd.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/stats.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/nfs4_mount.h>
+#include <linux/lockd/bind.h>
+#include <linux/smp_lock.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/nfs_idmap.h>
+#include <linux/vfs.h>
+#include <linux/namei.h>
+#include <linux/namespace.h>
+#include <linux/security.h>
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+#include "nfs4_fs.h"
+#include "delegation.h"
+#include "internal.h"
+
+#define NFSDBG_FACILITY         NFSDBG_CLIENT
+#define NFS_PARANOIA 1
+
+/*
+ * get an NFS2/NFS3 root dentry from the root filehandle
+ */
+struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
+{
+        struct nfs_server *server = NFS_SB(sb);
+        struct nfs_fsinfo fsinfo;
+        struct nfs_fattr fattr;
+        struct dentry *mntroot;
+        struct inode *inode;
+        int error;
+
+        /* create a dummy root dentry with dummy inode for this superblock */
+        if (!sb->s_root) {
+                struct nfs_fh dummyfh;
+                struct dentry *root;
+                struct inode *iroot;
+
+                memset(&dummyfh, 0, sizeof(dummyfh));
+                memset(&fattr, 0, sizeof(fattr));
+                nfs_fattr_init(&fattr);
+                fattr.valid = NFS_ATTR_FATTR;
+                fattr.type = NFDIR;
+                fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR;
+                fattr.nlink = 2;
+
+                iroot = nfs_fhget(sb, &dummyfh, &fattr);
+                if (IS_ERR(iroot))
+                        return ERR_PTR(PTR_ERR(iroot));
+
+                root = d_alloc_root(iroot);
+                if (!root) {
+                        iput(iroot);
+                        return ERR_PTR(-ENOMEM);
+                }
+
+                sb->s_root = root;
+        }
+
+        /* get the actual root for this mount */
+        fsinfo.fattr = &fattr;
+
+        error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
+        if (error < 0) {
+                dprintk("nfs_get_root: getattr error = %d\n", -error);
+                return ERR_PTR(error);
+        }
+
+        inode = nfs_fhget(sb, mntfh, fsinfo.fattr);
+        if (IS_ERR(inode)) {
+                dprintk("nfs_get_root: get root inode failed\n");
+                return ERR_PTR(PTR_ERR(inode));
+        }
+
+        /* root dentries normally start off anonymous and get spliced in later
+         * if the dentry tree reaches them; however if the dentry already
+         * exists, we'll pick it up at this point and use it as the root
+         */
+        mntroot = d_alloc_anon(inode);
+        if (!mntroot) {
+                iput(inode);
+                dprintk("nfs_get_root: get root dentry failed\n");
+                return ERR_PTR(-ENOMEM);
+        }
+
+        security_d_instantiate(mntroot, inode);
+
+        if (!mntroot->d_op)
+                mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops;
+
+        return mntroot;
+}
+
+#ifdef CONFIG_NFS_V4
+
+/*
+ * Do a simple pathwalk from the root FH of the server to the nominated target
+ * of the mountpoint
+ * - give error on symlinks
+ * - give error on ".." occurring in the path
+ * - follow traversals
+ */
+int nfs4_path_walk(struct nfs_server *server,
+                   struct nfs_fh *mntfh,
+                   const char *path)
+{
+        struct nfs_fsinfo fsinfo;
+        struct nfs_fattr fattr;
+        struct nfs_fh lastfh;
+        struct qstr name;
+        int ret;
+        //int referral_count = 0;
+
+        dprintk("--> nfs4_path_walk(,,%s)\n", path);
+
+        fsinfo.fattr = &fattr;
+        nfs_fattr_init(&fattr);
+
+        if (*path++ != '/') {
+                dprintk("nfs4_get_root: Path does not begin with a slash\n");
+                return -EINVAL;
+        }
+
+        /* Start by getting the root filehandle from the server */
+        ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
+        if (ret < 0) {
+                dprintk("nfs4_get_root: getroot error = %d\n", -ret);
+                return ret;
+        }
+
+        if (fattr.type != NFDIR) {
+                printk(KERN_ERR "nfs4_get_root:"
+                       " getroot encountered non-directory\n");
+                return -ENOTDIR;
+        }
+
+        if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) {
+                printk(KERN_ERR "nfs4_get_root:"
+                       " getroot obtained referral\n");
+                return -EREMOTE;
+        }
+
+next_component:
+        dprintk("Next: %s\n", path);
+
+        /* extract the next bit of the path */
+        if (!*path)
+                goto path_walk_complete;
+
+        name.name = path;
+        while (*path && *path != '/')
+                path++;
+        name.len = path - (const char *) name.name;
+
+eat_dot_dir:
+        while (*path == '/')
+                path++;
+
+        if (path[0] == '.' && (path[1] == '/' || !path[1])) {
+                path += 2;
+                goto eat_dot_dir;
+        }
+
+        if (path[0] == '.' && path[1] == '.' && (path[2] == '/' || !path[2])
+            ) {
+                printk(KERN_ERR "nfs4_get_root:"
+                       " Mount path contains reference to \"..\"\n");
+                return -EINVAL;
+        }
+
+        /* lookup the next FH in the sequence */
+        memcpy(&lastfh, mntfh, sizeof(lastfh));
+
+        dprintk("LookupFH: %*.*s [%s]\n", name.len, name.len, name.name, path);
+
+        ret = server->nfs_client->rpc_ops->lookupfh(server, &lastfh, &name,
+                                                    mntfh, &fattr);
+        if (ret < 0) {
+                dprintk("nfs4_get_root: getroot error = %d\n", -ret);
+                return ret;
+        }
+
+        if (fattr.type != NFDIR) {
+                printk(KERN_ERR "nfs4_get_root:"
+                       " lookupfh encountered non-directory\n");
+                return -ENOTDIR;
+        }
+
+        if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) {
+                printk(KERN_ERR "nfs4_get_root:"
+                       " lookupfh obtained referral\n");
+                return -EREMOTE;
+        }
+
+        goto next_component;
+
+path_walk_complete:
+        memcpy(&server->fsid, &fattr.fsid, sizeof(server->fsid));
+        dprintk("<-- nfs4_path_walk() = 0\n");
+        return 0;
+}
+
+/*
+ * get an NFS4 root dentry from the root filehandle
+ */
+struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
+{
+        struct nfs_server *server = NFS_SB(sb);
+        struct nfs_fattr fattr;
+        struct dentry *mntroot;
+        struct inode *inode;
+        int error;
+
+        dprintk("--> nfs4_get_root()\n");
+
+        /* create a dummy root dentry with dummy inode for this superblock */
+        if (!sb->s_root) {
+                struct nfs_fh dummyfh;
+                struct dentry *root;
+                struct inode *iroot;
+
+                memset(&dummyfh, 0, sizeof(dummyfh));
+                memset(&fattr, 0, sizeof(fattr));
+                nfs_fattr_init(&fattr);
+                fattr.valid = NFS_ATTR_FATTR;
+                fattr.type = NFDIR;
+                fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR;
+                fattr.nlink = 2;
+
+                iroot = nfs_fhget(sb, &dummyfh, &fattr);
+                if (IS_ERR(iroot))
+                        return ERR_PTR(PTR_ERR(iroot));
+
+                root = d_alloc_root(iroot);
+                if (!root) {
+                        iput(iroot);
+                        return ERR_PTR(-ENOMEM);
+                }
+
+                sb->s_root = root;
+        }
+
+        /* get the info about the server and filesystem */
+        error = nfs4_server_capabilities(server, mntfh);
+        if (error < 0) {
+                dprintk("nfs_get_root: getcaps error = %d\n",
+                        -error);
+                return ERR_PTR(error);
+        }
+
+        /* get the actual root for this mount */
+        error = server->nfs_client->rpc_ops->getattr(server, mntfh, &fattr);
+        if (error < 0) {
+                dprintk("nfs_get_root: getattr error = %d\n", -error);
+                return ERR_PTR(error);
+        }
+
+        inode = nfs_fhget(sb, mntfh, &fattr);
+        if (IS_ERR(inode)) {
+                dprintk("nfs_get_root: get root inode failed\n");
+                return ERR_PTR(PTR_ERR(inode));
+        }
+
+        /* root dentries normally start off anonymous and get spliced in later
+         * if the dentry tree reaches them; however if the dentry already
+         * exists, we'll pick it up at this point and use it as the root
+         */
+        mntroot = d_alloc_anon(inode);
+        if (!mntroot) {
+                iput(inode);
+                dprintk("nfs_get_root: get root dentry failed\n");
+                return ERR_PTR(-ENOMEM);
+        }
+
+        security_d_instantiate(mntroot, inode);
+
+        if (!mntroot->d_op)
+                mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops;
+
+        dprintk("<-- nfs4_get_root()\n");
+        return mntroot;
+}
+
+#endif /* CONFIG_NFS_V4 */