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-rw-r--r--fs/nfs/getroot.c311
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 */
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