Fixed MTP to work with TWRP

fs/nfs/nfs4namespace.c

@@ -0,0 +1,523 @@
+/*
+ * 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/nfs_mount.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/addr.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);
+}
+
+/*
+ * return the path component of "<server>:<path>"
+ *  nfspath - the "<server>:<path>" string
+ *  end - one past the last char that could contain "<server>:"
+ * returns NULL on failure
+ */
+static char *nfs_path_component(const char *nfspath, const char *end)
+{
+	char *p;
+
+	if (*nfspath == '[') {
+		/* parse [] escaped IPv6 addrs */
+		p = strchr(nfspath, ']');
+		if (p != NULL && ++p < end && *p == ':')
+			return p + 1;
+	} else {
+		/* otherwise split on first colon */
+		p = strchr(nfspath, ':');
+		if (p != NULL && p < end)
+			return p + 1;
+	}
+	return NULL;
+}
+
+/*
+ * 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,
+			      NFS_PATH_CANONICAL);
+	if (!IS_ERR(path)) {
+		char *path_component = nfs_path_component(path, limit);
+		if (path_component)
+			return path_component;
+	}
+	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, struct net *net)
+{
+	ssize_t ret;
+
+	ret = rpc_pton(net, string, len, sa, salen);
+	if (ret == 0) {
+		ret = nfs_dns_resolve_name(net, string, len, sa, salen);
+		if (ret < 0)
+			ret = 0;
+	}
+	return ret;
+}
+
+/**
+ * nfs_find_best_sec - Find a security mechanism supported locally
+ * @server: NFS server struct
+ * @flavors: List of security tuples returned by SECINFO procedure
+ *
+ * Return an rpc client that uses the first security mechanism in
+ * "flavors" that is locally supported.  The "flavors" array
+ * is searched in the order returned from the server, per RFC 3530
+ * recommendation and each flavor is checked for membership in the
+ * sec= mount option list if it exists.
+ *
+ * Return -EPERM if no matching flavor is found in the array.
+ *
+ * Please call rpc_shutdown_client() when you are done with this rpc client.
+ *
+ */
+static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt,
+					  struct nfs_server *server,
+					  struct nfs4_secinfo_flavors *flavors)
+{
+	rpc_authflavor_t pflavor;
+	struct nfs4_secinfo4 *secinfo;
+	unsigned int i;
+
+	for (i = 0; i < flavors->num_flavors; i++) {
+		secinfo = &flavors->flavors[i];
+
+		switch (secinfo->flavor) {
+		case RPC_AUTH_NULL:
+		case RPC_AUTH_UNIX:
+		case RPC_AUTH_GSS:
+			pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
+							&secinfo->flavor_info);
+			/* does the pseudoflavor match a sec= mount opt? */
+			if (pflavor != RPC_AUTH_MAXFLAVOR &&
+			    nfs_auth_info_match(&server->auth_info, pflavor)) {
+				struct rpc_clnt *new;
+				struct rpc_cred *cred;
+
+				/* Cloning creates an rpc_auth for the flavor */
+				new = rpc_clone_client_set_auth(clnt, pflavor);
+				if (IS_ERR(new))
+					continue;
+				/**
+				* Check that the user actually can use the
+				* flavor. This is mostly for RPC_AUTH_GSS
+				* where cr_init obtains a gss context
+				*/
+				cred = rpcauth_lookupcred(new->cl_auth, 0);
+				if (IS_ERR(cred)) {
+					rpc_shutdown_client(new);
+					continue;
+				}
+				put_rpccred(cred);
+				return new;
+			}
+		}
+	}
+	return ERR_PTR(-EPERM);
+}
+
+/**
+ * nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
+ * return an rpc_clnt that uses the best available security flavor with
+ * respect to the secinfo flavor list and the sec= mount options.
+ *
+ * @clnt: RPC client to clone
+ * @inode: directory inode
+ * @name: lookup name
+ *
+ * Please call rpc_shutdown_client() when you are done with this rpc client.
+ */
+struct rpc_clnt *
+nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode,
+					struct qstr *name)
+{
+	struct page *page;
+	struct nfs4_secinfo_flavors *flavors;
+	struct rpc_clnt *new;
+	int err;
+
+	page = alloc_page(GFP_KERNEL);
+	if (!page)
+		return ERR_PTR(-ENOMEM);
+
+	flavors = page_address(page);
+
+	err = nfs4_proc_secinfo(inode, name, flavors);
+	if (err < 0) {
+		new = ERR_PTR(err);
+		goto out;
+	}
+
+	new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);
+
+out:
+	put_page(page);
+	return new;
+}
+
+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 net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
+	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, net);
+		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 %pd2\n", __func__, dentry);
+
+	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
+ *
+ */
+static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, 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 %pd2\n",
+		__func__, dentry);
+
+	err = nfs4_proc_fs_locations(client, 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;
+}
+
+struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
+			       struct nfs_fh *fh, struct nfs_fattr *fattr)
+{
+	rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
+	struct dentry *parent = dget_parent(dentry);
+	struct inode *dir = parent->d_inode;
+	struct qstr *name = &dentry->d_name;
+	struct rpc_clnt *client;
+	struct vfsmount *mnt;
+
+	/* Look it up again to get its attributes and sec flavor */
+	client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
+	dput(parent);
+	if (IS_ERR(client))
+		return ERR_CAST(client);
+
+	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
+		mnt = nfs_do_refmount(client, dentry);
+		goto out;
+	}
+
+	if (client->cl_auth->au_flavor != flavor)
+		flavor = client->cl_auth->au_flavor;
+	mnt = nfs_do_submount(dentry, fh, fattr, flavor);
+out:
+	rpc_shutdown_client(client);
+	return mnt;
+}
+
+/*
+ * Try one location from the fs_locations array.
+ *
+ * Returns zero on success, or a negative errno value.
+ */
+static int nfs4_try_replacing_one_location(struct nfs_server *server,
+		char *page, char *page2,
+		const struct nfs4_fs_location *location)
+{
+	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
+	struct net *net = rpc_net_ns(server->client);
+	struct sockaddr *sap;
+	unsigned int s;
+	size_t salen;
+	int error;
+
+	sap = kmalloc(addr_bufsize, GFP_KERNEL);
+	if (sap == NULL)
+		return -ENOMEM;
+
+	error = -ENOENT;
+	for (s = 0; s < location->nservers; s++) {
+		const struct nfs4_string *buf = &location->servers[s];
+		char *hostname;
+
+		if (buf->len <= 0 || buf->len > PAGE_SIZE)
+			continue;
+
+		if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
+			continue;
+
+		salen = nfs_parse_server_name(buf->data, buf->len,
+						sap, addr_bufsize, net);
+		if (salen == 0)
+			continue;
+		rpc_set_port(sap, NFS_PORT);
+
+		error = -ENOMEM;
+		hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
+		if (hostname == NULL)
+			break;
+
+		error = nfs4_update_server(server, hostname, sap, salen, net);
+		kfree(hostname);
+		if (error == 0)
+			break;
+	}
+
+	kfree(sap);
+	return error;
+}
+
+/**
+ * nfs4_replace_transport - set up transport to destination server
+ *
+ * @server: export being migrated
+ * @locations: fs_locations array
+ *
+ * Returns zero on success, or a negative errno value.
+ *
+ * The client tries all the entries in the "locations" array, in the
+ * order returned by the server, until one works or the end of the
+ * array is reached.
+ */
+int nfs4_replace_transport(struct nfs_server *server,
+			   const struct nfs4_fs_locations *locations)
+{
+	char *page = NULL, *page2 = NULL;
+	int loc, error;
+
+	error = -ENOENT;
+	if (locations == NULL || locations->nlocations <= 0)
+		goto out;
+
+	error = -ENOMEM;
+	page = (char *) __get_free_page(GFP_USER);
+	if (!page)
+		goto out;
+	page2 = (char *) __get_free_page(GFP_USER);
+	if (!page2)
+		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;
+
+		error = nfs4_try_replacing_one_location(server, page,
+							page2, location);
+		if (error == 0)
+			break;
+	}
+
+out:
+	free_page((unsigned long)page);
+	free_page((unsigned long)page2);
+	return error;
+}