1 files changed, 265 insertions, 0 deletions
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
new file mode 100644
index 00000000..bb80c49b
--- /dev/null
+++ b/fs/nfs/nfs4namespace.c
@@ -0,0 +1,265 @@
+/*
+ * linux/fs/nfs/nfs4namespace.c
+ *
+ * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
+ * - Modified by David Howells <dhowells@redhat.com>
+ *
+ * NFSv4 namespace
+ */
+
+#include <linux/dcache.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/nfs_fs.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/vfs.h>
+#include <linux/inet.h>
+#include "internal.h"
+#include "nfs4_fs.h"
+#include "dns_resolve.h"
+
+#define NFSDBG_FACILITY		NFSDBG_VFS
+
+/*
+ * Convert the NFSv4 pathname components into a standard posix path.
+ *
+ * Note that the resulting string will be placed at the end of the buffer
+ */
+static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
+					 char *buffer, ssize_t buflen)
+{
+	char *end = buffer + buflen;
+	int n;
+
+	*--end = '\0';
+	buflen--;
+
+	n = pathname->ncomponents;
+	while (--n >= 0) {
+		const struct nfs4_string *component = &pathname->components[n];
+		buflen -= component->len + 1;
+		if (buflen < 0)
+			goto Elong;
+		end -= component->len;
+		memcpy(end, component->data, component->len);
+		*--end = '/';
+	}
+	return end;
+Elong:
+	return ERR_PTR(-ENAMETOOLONG);
+}
+
+/*
+ * Determine the mount path as a string
+ */
+static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
+{
+	char *limit;
+	char *path = nfs_path(&limit, dentry, buffer, buflen);
+	if (!IS_ERR(path)) {
+		char *colon = strchr(path, ':');
+		if (colon && colon < limit)
+			path = colon + 1;
+	}
+	return path;
+}
+
+/*
+ * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
+ * believe to be the server path to this dentry
+ */
+static int nfs4_validate_fspath(struct dentry *dentry,
+				const struct nfs4_fs_locations *locations,
+				char *page, char *page2)
+{
+	const char *path, *fs_path;
+
+	path = nfs4_path(dentry, page, PAGE_SIZE);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+
+	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
+	if (IS_ERR(fs_path))
+		return PTR_ERR(fs_path);
+
+	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
+		dprintk("%s: path %s does not begin with fsroot %s\n",
+			__func__, path, fs_path);
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+static size_t nfs_parse_server_name(char *string, size_t len,
+		struct sockaddr *sa, size_t salen)
+{
+	ssize_t ret;
+
+	ret = rpc_pton(string, len, sa, salen);
+	if (ret == 0) {
+		ret = nfs_dns_resolve_name(string, len, sa, salen);
+		if (ret < 0)
+			ret = 0;
+	}
+	return ret;
+}
+
+static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
+				     char *page, char *page2,
+				     const struct nfs4_fs_location *location)
+{
+	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
+	struct vfsmount *mnt = ERR_PTR(-ENOENT);
+	char *mnt_path;
+	unsigned int maxbuflen;
+	unsigned int s;
+
+	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
+	if (IS_ERR(mnt_path))
+		return ERR_CAST(mnt_path);
+	mountdata->mnt_path = mnt_path;
+	maxbuflen = mnt_path - 1 - page2;
+
+	mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
+	if (mountdata->addr == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	for (s = 0; s < location->nservers; s++) {
+		const struct nfs4_string *buf = &location->servers[s];
+
+		if (buf->len <= 0 || buf->len >= maxbuflen)
+			continue;
+
+		if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
+			continue;
+
+		mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
+				mountdata->addr, addr_bufsize);
+		if (mountdata->addrlen == 0)
+			continue;
+
+		rpc_set_port(mountdata->addr, NFS_PORT);
+
+		memcpy(page2, buf->data, buf->len);
+		page2[buf->len] = '\0';
+		mountdata->hostname = page2;
+
+		snprintf(page, PAGE_SIZE, "%s:%s",
+				mountdata->hostname,
+				mountdata->mnt_path);
+
+		mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
+		if (!IS_ERR(mnt))
+			break;
+	}
+	kfree(mountdata->addr);
+	return mnt;
+}
+
+/**
+ * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
+ * @dentry - parent directory
+ * @locations - array of NFSv4 server location information
+ *
+ */
+static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
+					    const struct nfs4_fs_locations *locations)
+{
+	struct vfsmount *mnt = ERR_PTR(-ENOENT);
+	struct nfs_clone_mount mountdata = {
+		.sb = dentry->d_sb,
+		.dentry = dentry,
+		.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
+	};
+	char *page = NULL, *page2 = NULL;
+	int loc, error;
+
+	if (locations == NULL || locations->nlocations <= 0)
+		goto out;
+
+	dprintk("%s: referral at %s/%s\n", __func__,
+		dentry->d_parent->d_name.name, dentry->d_name.name);
+
+	page = (char *) __get_free_page(GFP_USER);
+	if (!page)
+		goto out;
+
+	page2 = (char *) __get_free_page(GFP_USER);
+	if (!page2)
+		goto out;
+
+	/* Ensure fs path is a prefix of current dentry path */
+	error = nfs4_validate_fspath(dentry, locations, page, page2);
+	if (error < 0) {
+		mnt = ERR_PTR(error);
+		goto out;
+	}
+
+	for (loc = 0; loc < locations->nlocations; loc++) {
+		const struct nfs4_fs_location *location = &locations->locations[loc];
+
+		if (location == NULL || location->nservers <= 0 ||
+		    location->rootpath.ncomponents == 0)
+			continue;
+
+		mnt = try_location(&mountdata, page, page2, location);
+		if (!IS_ERR(mnt))
+			break;
+	}
+
+out:
+	free_page((unsigned long) page);
+	free_page((unsigned long) page2);
+	dprintk("%s: done\n", __func__);
+	return mnt;
+}
+
+/*
+ * nfs_do_refmount - handle crossing a referral on server
+ * @dentry - dentry of referral
+ *
+ */
+struct vfsmount *nfs_do_refmount(struct dentry *dentry)
+{
+	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
+	struct dentry *parent;
+	struct nfs4_fs_locations *fs_locations = NULL;
+	struct page *page;
+	int err;
+
+	/* BUG_ON(IS_ROOT(dentry)); */
+	dprintk("%s: enter\n", __func__);
+
+	page = alloc_page(GFP_KERNEL);
+	if (page == NULL)
+		goto out;
+
+	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
+	if (fs_locations == NULL)
+		goto out_free;
+
+	/* Get locations */
+	mnt = ERR_PTR(-ENOENT);
+
+	parent = dget_parent(dentry);
+	dprintk("%s: getting locations for %s/%s\n",
+		__func__, parent->d_name.name, dentry->d_name.name);
+
+	err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
+	dput(parent);
+	if (err != 0 ||
+	    fs_locations->nlocations <= 0 ||
+	    fs_locations->fs_path.ncomponents <= 0)
+		goto out_free;
+
+	mnt = nfs_follow_referral(dentry, fs_locations);
+out_free:
+	__free_page(page);
+	kfree(fs_locations);
+out:
+	dprintk("%s: done\n", __func__);
+	return mnt;
+}