Merge tag 'nfs-for-4.1-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Another set of mainly bugfixes and a couple of cleanups.  No new
  functionality in this round.

  Highlights include:

  Stable patches:
   - Fix a regression in /proc/self/mountstats
   - Fix the pNFS flexfiles O_DIRECT support
   - Fix high load average due to callback thread sleeping

  Bugfixes:
   - Various patches to fix the pNFS layoutcommit support
   - Do not cache pNFS deviceids unless server notifications are enabled
   - Fix a SUNRPC transport reconnection regression
   - make debugfs file creation failure non-fatal in SUNRPC
   - Another fix for circular directory warnings on NFSv4 "junctioned"
     mountpoints
   - Fix locking around NFSv4.2 fallocate() support
   - Truncating NFSv4 file opens should also sync O_DIRECT writes
   - Prevent infinite loop in rpcrdma_ep_create()

  Features:
   - Various improvements to the RDMA transport code's handling of
     memory registration
   - Various code cleanups"

* tag 'nfs-for-4.1-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (55 commits)
  fs/nfs: fix new compiler warning about boolean in switch
  nfs: Remove unneeded casts in nfs
  NFS: Don't attempt to decode missing directory entries
  Revert "nfs: replace nfs_add_stats with nfs_inc_stats when add one"
  NFS: Rename idmap.c to nfs4idmap.c
  NFS: Move nfs_idmap.h into fs/nfs/
  NFS: Remove CONFIG_NFS_V4 checks from nfs_idmap.h
  NFS: Add a stub for GETDEVICELIST
  nfs: remove WARN_ON_ONCE from nfs_direct_good_bytes
  nfs: fix DIO good bytes calculation
  nfs: Fetch MOUNTED_ON_FILEID when updating an inode
  sunrpc: make debugfs file creation failure non-fatal
  nfs: fix high load average due to callback thread sleeping
  NFS: Reduce time spent holding the i_mutex during fallocate()
  NFS: Don't zap caches on fallocate()
  xprtrdma: Make rpcrdma_{un}map_one() into inline functions
  xprtrdma: Handle non-SEND completions via a callout
  xprtrdma: Add "open" memreg op
  xprtrdma: Add "destroy MRs" memreg op
  xprtrdma: Add "reset MRs" memreg op
  ...

1 files changed, 792 insertions, 0 deletions

diff --git a/fs/nfs/nfs4idmap.c b/fs/nfs/nfs4idmap.c
new file mode 100644
index 000000000000..2e1737c40a29
--- /dev/null
+++ b/fs/nfs/nfs4idmap.c
@@ -0,0 +1,792 @@
+/*
+ * fs/nfs/idmap.c
+ *
+ *  UID and GID to name mapping for clients.
+ *
+ *  Copyright (c) 2002 The Regents of the University of Michigan.
+ *  All rights reserved.
+ *
+ *  Marius Aamodt Eriksen <marius@umich.edu>
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions
+ *  are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *  3. Neither the name of the University nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <linux/types.h>
+#include <linux/parser.h>
+#include <linux/fs.h>
+#include <net/net_namespace.h>
+#include <linux/sunrpc/rpc_pipe_fs.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_fs_sb.h>
+#include <linux/key.h>
+#include <linux/keyctl.h>
+#include <linux/key-type.h>
+#include <keys/user-type.h>
+#include <linux/module.h>
+
+#include "internal.h"
+#include "netns.h"
+#include "nfs4idmap.h"
+#include "nfs4trace.h"
+
+#define NFS_UINT_MAXLEN 11
+
+static const struct cred *id_resolver_cache;
+static struct key_type key_type_id_resolver_legacy;
+
+struct idmap_legacy_upcalldata {
+	struct rpc_pipe_msg pipe_msg;
+	struct idmap_msg idmap_msg;
+	struct key_construction	*key_cons;
+	struct idmap *idmap;
+};
+
+struct idmap {
+	struct rpc_pipe_dir_object idmap_pdo;
+	struct rpc_pipe		*idmap_pipe;
+	struct idmap_legacy_upcalldata *idmap_upcall_data;
+	struct mutex		idmap_mutex;
+};
+
+/**
+ * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
+ * @fattr: fully initialised struct nfs_fattr
+ * @owner_name: owner name string cache
+ * @group_name: group name string cache
+ */
+void nfs_fattr_init_names(struct nfs_fattr *fattr,
+		struct nfs4_string *owner_name,
+		struct nfs4_string *group_name)
+{
+	fattr->owner_name = owner_name;
+	fattr->group_name = group_name;
+}
+
+static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
+{
+	fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
+	kfree(fattr->owner_name->data);
+}
+
+static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
+{
+	fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
+	kfree(fattr->group_name->data);
+}
+
+static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
+{
+	struct nfs4_string *owner = fattr->owner_name;
+	kuid_t uid;
+
+	if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
+		return false;
+	if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
+		fattr->uid = uid;
+		fattr->valid |= NFS_ATTR_FATTR_OWNER;
+	}
+	return true;
+}
+
+static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
+{
+	struct nfs4_string *group = fattr->group_name;
+	kgid_t gid;
+
+	if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
+		return false;
+	if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
+		fattr->gid = gid;
+		fattr->valid |= NFS_ATTR_FATTR_GROUP;
+	}
+	return true;
+}
+
+/**
+ * nfs_fattr_free_names - free up the NFSv4 owner and group strings
+ * @fattr: a fully initialised nfs_fattr structure
+ */
+void nfs_fattr_free_names(struct nfs_fattr *fattr)
+{
+	if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
+		nfs_fattr_free_owner_name(fattr);
+	if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
+		nfs_fattr_free_group_name(fattr);
+}
+
+/**
+ * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
+ * @server: pointer to the filesystem nfs_server structure
+ * @fattr: a fully initialised nfs_fattr structure
+ *
+ * This helper maps the cached NFSv4 owner/group strings in fattr into
+ * their numeric uid/gid equivalents, and then frees the cached strings.
+ */
+void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
+{
+	if (nfs_fattr_map_owner_name(server, fattr))
+		nfs_fattr_free_owner_name(fattr);
+	if (nfs_fattr_map_group_name(server, fattr))
+		nfs_fattr_free_group_name(fattr);
+}
+
+int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
+{
+	unsigned long val;
+	char buf[16];
+
+	if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
+		return 0;
+	memcpy(buf, name, namelen);
+	buf[namelen] = '\0';
+	if (kstrtoul(buf, 0, &val) != 0)
+		return 0;
+	*res = val;
+	return 1;
+}
+EXPORT_SYMBOL_GPL(nfs_map_string_to_numeric);
+
+static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
+{
+	return snprintf(buf, buflen, "%u", id);
+}
+
+static struct key_type key_type_id_resolver = {
+	.name		= "id_resolver",
+	.preparse	= user_preparse,
+	.free_preparse	= user_free_preparse,
+	.instantiate	= generic_key_instantiate,
+	.revoke		= user_revoke,
+	.destroy	= user_destroy,
+	.describe	= user_describe,
+	.read		= user_read,
+};
+
+static int nfs_idmap_init_keyring(void)
+{
+	struct cred *cred;
+	struct key *keyring;
+	int ret = 0;
+
+	printk(KERN_NOTICE "NFS: Registering the %s key type\n",
+		key_type_id_resolver.name);
+
+	cred = prepare_kernel_cred(NULL);
+	if (!cred)
+		return -ENOMEM;
+
+	keyring = keyring_alloc(".id_resolver",
+				GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
+				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
+				KEY_USR_VIEW | KEY_USR_READ,
+				KEY_ALLOC_NOT_IN_QUOTA, NULL);
+	if (IS_ERR(keyring)) {
+		ret = PTR_ERR(keyring);
+		goto failed_put_cred;
+	}
+
+	ret = register_key_type(&key_type_id_resolver);
+	if (ret < 0)
+		goto failed_put_key;
+
+	ret = register_key_type(&key_type_id_resolver_legacy);
+	if (ret < 0)
+		goto failed_reg_legacy;
+
+	set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
+	cred->thread_keyring = keyring;
+	cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
+	id_resolver_cache = cred;
+	return 0;
+
+failed_reg_legacy:
+	unregister_key_type(&key_type_id_resolver);
+failed_put_key:
+	key_put(keyring);
+failed_put_cred:
+	put_cred(cred);
+	return ret;
+}
+
+static void nfs_idmap_quit_keyring(void)
+{
+	key_revoke(id_resolver_cache->thread_keyring);
+	unregister_key_type(&key_type_id_resolver);
+	unregister_key_type(&key_type_id_resolver_legacy);
+	put_cred(id_resolver_cache);
+}
+
+/*
+ * Assemble the description to pass to request_key()
+ * This function will allocate a new string and update dest to point
+ * at it.  The caller is responsible for freeing dest.
+ *
+ * On error 0 is returned.  Otherwise, the length of dest is returned.
+ */
+static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
+				const char *type, size_t typelen, char **desc)
+{
+	char *cp;
+	size_t desclen = typelen + namelen + 2;
+
+	*desc = kmalloc(desclen, GFP_KERNEL);
+	if (!*desc)
+		return -ENOMEM;
+
+	cp = *desc;
+	memcpy(cp, type, typelen);
+	cp += typelen;
+	*cp++ = ':';
+
+	memcpy(cp, name, namelen);
+	cp += namelen;
+	*cp = '\0';
+	return desclen;
+}
+
+static struct key *nfs_idmap_request_key(const char *name, size_t namelen,
+					 const char *type, struct idmap *idmap)
+{
+	char *desc;
+	struct key *rkey;
+	ssize_t ret;
+
+	ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
+	if (ret <= 0)
+		return ERR_PTR(ret);
+
+	rkey = request_key(&key_type_id_resolver, desc, "");
+	if (IS_ERR(rkey)) {
+		mutex_lock(&idmap->idmap_mutex);
+		rkey = request_key_with_auxdata(&key_type_id_resolver_legacy,
+						desc, "", 0, idmap);
+		mutex_unlock(&idmap->idmap_mutex);
+	}
+	if (!IS_ERR(rkey))
+		set_bit(KEY_FLAG_ROOT_CAN_INVAL, &rkey->flags);
+
+	kfree(desc);
+	return rkey;
+}
+
+static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
+				 const char *type, void *data,
+				 size_t data_size, struct idmap *idmap)
+{
+	const struct cred *saved_cred;
+	struct key *rkey;
+	struct user_key_payload *payload;
+	ssize_t ret;
+
+	saved_cred = override_creds(id_resolver_cache);
+	rkey = nfs_idmap_request_key(name, namelen, type, idmap);
+	revert_creds(saved_cred);
+
+	if (IS_ERR(rkey)) {
+		ret = PTR_ERR(rkey);
+		goto out;
+	}
+
+	rcu_read_lock();
+	rkey->perm |= KEY_USR_VIEW;
+
+	ret = key_validate(rkey);
+	if (ret < 0)
+		goto out_up;
+
+	payload = rcu_dereference(rkey->payload.rcudata);
+	if (IS_ERR_OR_NULL(payload)) {
+		ret = PTR_ERR(payload);
+		goto out_up;
+	}
+
+	ret = payload->datalen;
+	if (ret > 0 && ret <= data_size)
+		memcpy(data, payload->data, ret);
+	else
+		ret = -EINVAL;
+
+out_up:
+	rcu_read_unlock();
+	key_put(rkey);
+out:
+	return ret;
+}
+
+/* ID -> Name */
+static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
+				     size_t buflen, struct idmap *idmap)
+{
+	char id_str[NFS_UINT_MAXLEN];
+	int id_len;
+	ssize_t ret;
+
+	id_len = snprintf(id_str, sizeof(id_str), "%u", id);
+	ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
+	if (ret < 0)
+		return -EINVAL;
+	return ret;
+}
+
+/* Name -> ID */
+static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
+			       __u32 *id, struct idmap *idmap)
+{
+	char id_str[NFS_UINT_MAXLEN];
+	long id_long;
+	ssize_t data_size;
+	int ret = 0;
+
+	data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
+	if (data_size <= 0) {
+		ret = -EINVAL;
+	} else {
+		ret = kstrtol(id_str, 10, &id_long);
+		*id = (__u32)id_long;
+	}
+	return ret;
+}
+
+/* idmap classic begins here */
+
+enum {
+	Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
+};
+
+static const match_table_t nfs_idmap_tokens = {
+	{ Opt_find_uid, "uid:%s" },
+	{ Opt_find_gid, "gid:%s" },
+	{ Opt_find_user, "user:%s" },
+	{ Opt_find_group, "group:%s" },
+	{ Opt_find_err, NULL }
+};
+
+static int nfs_idmap_legacy_upcall(struct key_construction *, const char *, void *);
+static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
+				   size_t);
+static void idmap_release_pipe(struct inode *);
+static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
+
+static const struct rpc_pipe_ops idmap_upcall_ops = {
+	.upcall		= rpc_pipe_generic_upcall,
+	.downcall	= idmap_pipe_downcall,
+	.release_pipe	= idmap_release_pipe,
+	.destroy_msg	= idmap_pipe_destroy_msg,
+};
+
+static struct key_type key_type_id_resolver_legacy = {
+	.name		= "id_legacy",
+	.preparse	= user_preparse,
+	.free_preparse	= user_free_preparse,
+	.instantiate	= generic_key_instantiate,
+	.revoke		= user_revoke,
+	.destroy	= user_destroy,
+	.describe	= user_describe,
+	.read		= user_read,
+	.request_key	= nfs_idmap_legacy_upcall,
+};
+
+static void nfs_idmap_pipe_destroy(struct dentry *dir,
+		struct rpc_pipe_dir_object *pdo)
+{
+	struct idmap *idmap = pdo->pdo_data;
+	struct rpc_pipe *pipe = idmap->idmap_pipe;
+
+	if (pipe->dentry) {
+		rpc_unlink(pipe->dentry);
+		pipe->dentry = NULL;
+	}
+}
+
+static int nfs_idmap_pipe_create(struct dentry *dir,
+		struct rpc_pipe_dir_object *pdo)
+{
+	struct idmap *idmap = pdo->pdo_data;
+	struct rpc_pipe *pipe = idmap->idmap_pipe;
+	struct dentry *dentry;
+
+	dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+	pipe->dentry = dentry;
+	return 0;
+}
+
+static const struct rpc_pipe_dir_object_ops nfs_idmap_pipe_dir_object_ops = {
+	.create = nfs_idmap_pipe_create,
+	.destroy = nfs_idmap_pipe_destroy,
+};
+
+int
+nfs_idmap_new(struct nfs_client *clp)
+{
+	struct idmap *idmap;
+	struct rpc_pipe *pipe;
+	int error;
+
+	idmap = kzalloc(sizeof(*idmap), GFP_KERNEL);
+	if (idmap == NULL)
+		return -ENOMEM;
+
+	rpc_init_pipe_dir_object(&idmap->idmap_pdo,
+			&nfs_idmap_pipe_dir_object_ops,
+			idmap);
+
+	pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
+	if (IS_ERR(pipe)) {
+		error = PTR_ERR(pipe);
+		goto err;
+	}
+	idmap->idmap_pipe = pipe;
+	mutex_init(&idmap->idmap_mutex);
+
+	error = rpc_add_pipe_dir_object(clp->cl_net,
+			&clp->cl_rpcclient->cl_pipedir_objects,
+			&idmap->idmap_pdo);
+	if (error)
+		goto err_destroy_pipe;
+
+	clp->cl_idmap = idmap;
+	return 0;
+err_destroy_pipe:
+	rpc_destroy_pipe_data(idmap->idmap_pipe);
+err:
+	kfree(idmap);
+	return error;
+}
+
+void
+nfs_idmap_delete(struct nfs_client *clp)
+{
+	struct idmap *idmap = clp->cl_idmap;
+
+	if (!idmap)
+		return;
+	clp->cl_idmap = NULL;
+	rpc_remove_pipe_dir_object(clp->cl_net,
+			&clp->cl_rpcclient->cl_pipedir_objects,
+			&idmap->idmap_pdo);
+	rpc_destroy_pipe_data(idmap->idmap_pipe);
+	kfree(idmap);
+}
+
+int nfs_idmap_init(void)
+{
+	int ret;
+	ret = nfs_idmap_init_keyring();
+	if (ret != 0)
+		goto out;
+out:
+	return ret;
+}
+
+void nfs_idmap_quit(void)
+{
+	nfs_idmap_quit_keyring();
+}
+
+static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
+				     struct idmap_msg *im,
+				     struct rpc_pipe_msg *msg)
+{
+	substring_t substr;
+	int token, ret;
+
+	im->im_type = IDMAP_TYPE_GROUP;
+	token = match_token(desc, nfs_idmap_tokens, &substr);
+
+	switch (token) {
+	case Opt_find_uid:
+		im->im_type = IDMAP_TYPE_USER;
+	case Opt_find_gid:
+		im->im_conv = IDMAP_CONV_NAMETOID;
+		ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
+		break;
+
+	case Opt_find_user:
+		im->im_type = IDMAP_TYPE_USER;
+	case Opt_find_group:
+		im->im_conv = IDMAP_CONV_IDTONAME;
+		ret = match_int(&substr, &im->im_id);
+		break;
+
+	default:
+		ret = -EINVAL;
+		goto out;
+	}
+
+	msg->data = im;
+	msg->len  = sizeof(struct idmap_msg);
+
+out:
+	return ret;
+}
+
+static bool
+nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
+		struct idmap_legacy_upcalldata *data)
+{
+	if (idmap->idmap_upcall_data != NULL) {
+		WARN_ON_ONCE(1);
+		return false;
+	}
+	idmap->idmap_upcall_data = data;
+	return true;
+}
+
+static void
+nfs_idmap_complete_pipe_upcall_locked(struct idmap *idmap, int ret)
+{
+	struct key_construction *cons = idmap->idmap_upcall_data->key_cons;
+
+	kfree(idmap->idmap_upcall_data);
+	idmap->idmap_upcall_data = NULL;
+	complete_request_key(cons, ret);
+}
+
+static void
+nfs_idmap_abort_pipe_upcall(struct idmap *idmap, int ret)
+{
+	if (idmap->idmap_upcall_data != NULL)
+		nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
+}
+
+static int nfs_idmap_legacy_upcall(struct key_construction *cons,
+				   const char *op,
+				   void *aux)
+{
+	struct idmap_legacy_upcalldata *data;
+	struct rpc_pipe_msg *msg;
+	struct idmap_msg *im;
+	struct idmap *idmap = (struct idmap *)aux;
+	struct key *key = cons->key;
+	int ret = -ENOMEM;
+
+	/* msg and im are freed in idmap_pipe_destroy_msg */
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		goto out1;
+
+	msg = &data->pipe_msg;
+	im = &data->idmap_msg;
+	data->idmap = idmap;
+	data->key_cons = cons;
+
+	ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
+	if (ret < 0)
+		goto out2;
+
+	ret = -EAGAIN;
+	if (!nfs_idmap_prepare_pipe_upcall(idmap, data))
+		goto out2;
+
+	ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
+	if (ret < 0)
+		nfs_idmap_abort_pipe_upcall(idmap, ret);
+
+	return ret;
+out2:
+	kfree(data);
+out1:
+	complete_request_key(cons, ret);
+	return ret;
+}
+
+static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data, size_t datalen)
+{
+	return key_instantiate_and_link(key, data, datalen,
+					id_resolver_cache->thread_keyring,
+					authkey);
+}
+
+static int nfs_idmap_read_and_verify_message(struct idmap_msg *im,
+		struct idmap_msg *upcall,
+		struct key *key, struct key *authkey)
+{
+	char id_str[NFS_UINT_MAXLEN];
+	size_t len;
+	int ret = -ENOKEY;
+
+	/* ret = -ENOKEY */
+	if (upcall->im_type != im->im_type || upcall->im_conv != im->im_conv)
+		goto out;
+	switch (im->im_conv) {
+	case IDMAP_CONV_NAMETOID:
+		if (strcmp(upcall->im_name, im->im_name) != 0)
+			break;
+		/* Note: here we store the NUL terminator too */
+		len = sprintf(id_str, "%d", im->im_id) + 1;
+		ret = nfs_idmap_instantiate(key, authkey, id_str, len);
+		break;
+	case IDMAP_CONV_IDTONAME:
+		if (upcall->im_id != im->im_id)
+			break;
+		len = strlen(im->im_name);
+		ret = nfs_idmap_instantiate(key, authkey, im->im_name, len);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+out:
+	return ret;
+}
+
+static ssize_t
+idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
+{
+	struct rpc_inode *rpci = RPC_I(file_inode(filp));
+	struct idmap *idmap = (struct idmap *)rpci->private;
+	struct key_construction *cons;
+	struct idmap_msg im;
+	size_t namelen_in;
+	int ret = -ENOKEY;
+
+	/* If instantiation is successful, anyone waiting for key construction
+	 * will have been woken up and someone else may now have used
+	 * idmap_key_cons - so after this point we may no longer touch it.
+	 */
+	if (idmap->idmap_upcall_data == NULL)
+		goto out_noupcall;
+
+	cons = idmap->idmap_upcall_data->key_cons;
+
+	if (mlen != sizeof(im)) {
+		ret = -ENOSPC;
+		goto out;
+	}
+
+	if (copy_from_user(&im, src, mlen) != 0) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
+		ret = -ENOKEY;
+		goto out;
+	}
+
+	namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
+	if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
+		ret = -EINVAL;
+		goto out;
+}
+
+	ret = nfs_idmap_read_and_verify_message(&im,
+			&idmap->idmap_upcall_data->idmap_msg,
+			cons->key, cons->authkey);
+	if (ret >= 0) {
+		key_set_timeout(cons->key, nfs_idmap_cache_timeout);
+		ret = mlen;
+	}
+
+out:
+	nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
+out_noupcall:
+	return ret;
+}
+
+static void
+idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
+{
+	struct idmap_legacy_upcalldata *data = container_of(msg,
+			struct idmap_legacy_upcalldata,
+			pipe_msg);
+	struct idmap *idmap = data->idmap;
+
+	if (msg->errno)
+		nfs_idmap_abort_pipe_upcall(idmap, msg->errno);
+}
+
+static void
+idmap_release_pipe(struct inode *inode)
+{
+	struct rpc_inode *rpci = RPC_I(inode);
+	struct idmap *idmap = (struct idmap *)rpci->private;
+
+	nfs_idmap_abort_pipe_upcall(idmap, -EPIPE);
+}
+
+int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, kuid_t *uid)
+{
+	struct idmap *idmap = server->nfs_client->cl_idmap;
+	__u32 id = -1;
+	int ret = 0;
+
+	if (!nfs_map_string_to_numeric(name, namelen, &id))
+		ret = nfs_idmap_lookup_id(name, namelen, "uid", &id, idmap);
+	if (ret == 0) {
+		*uid = make_kuid(&init_user_ns, id);
+		if (!uid_valid(*uid))
+			ret = -ERANGE;
+	}
+	trace_nfs4_map_name_to_uid(name, namelen, id, ret);
+	return ret;
+}
+
+int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, kgid_t *gid)
+{
+	struct idmap *idmap = server->nfs_client->cl_idmap;
+	__u32 id = -1;
+	int ret = 0;
+
+	if (!nfs_map_string_to_numeric(name, namelen, &id))
+		ret = nfs_idmap_lookup_id(name, namelen, "gid", &id, idmap);
+	if (ret == 0) {
+		*gid = make_kgid(&init_user_ns, id);
+		if (!gid_valid(*gid))
+			ret = -ERANGE;
+	}
+	trace_nfs4_map_group_to_gid(name, namelen, id, ret);
+	return ret;
+}
+
+int nfs_map_uid_to_name(const struct nfs_server *server, kuid_t uid, char *buf, size_t buflen)
+{
+	struct idmap *idmap = server->nfs_client->cl_idmap;
+	int ret = -EINVAL;
+	__u32 id;
+
+	id = from_kuid(&init_user_ns, uid);
+	if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
+		ret = nfs_idmap_lookup_name(id, "user", buf, buflen, idmap);
+	if (ret < 0)
+		ret = nfs_map_numeric_to_string(id, buf, buflen);
+	trace_nfs4_map_uid_to_name(buf, ret, id, ret);
+	return ret;
+}
+int nfs_map_gid_to_group(const struct nfs_server *server, kgid_t gid, char *buf, size_t buflen)
+{
+	struct idmap *idmap = server->nfs_client->cl_idmap;
+	int ret = -EINVAL;
+	__u32 id;
+
+	id = from_kgid(&init_user_ns, gid);
+	if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
+		ret = nfs_idmap_lookup_name(id, "group", buf, buflen, idmap);
+	if (ret < 0)
+		ret = nfs_map_numeric_to_string(id, buf, buflen);
+	trace_nfs4_map_gid_to_group(buf, ret, id, ret);
+	return ret;
+}