Merge tag '5.11-rc-smb3' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs updates from Steve French:
 "The largest part are for support of the newer mount API which has been
  needed for cifs/smb3 mounts for a long time due to the new API's
  better handling of remount, and better error reporting. There are
  three additional small cleanup patches for this being tested, that are
  not included yet.

  This series also includes addition of support for the SMB3 witness
  protocol which can provide important notifications from the server to
  client on server address or export or network changes. This can be
  useful for example in order to be notified before the failure - when a
  server's IP address changes (in the future it will allow us to support
  server notifications of when a share is moved).

  It also includes three patches for stable e.g. some that better handle
  some confusing error messages during session establishment"

* tag '5.11-rc-smb3' of git://git.samba.org/sfrench/cifs-2.6: (55 commits)
  cifs: update internal module version number
  cifs: Fix support for remount when not changing rsize/wsize
  cifs: handle "guest" mount parameter
  cifs: correct four aliased mount parms to allow use of previous names
  cifs: Tracepoints and logs for tracing credit changes.
  cifs: fix use after free in cifs_smb3_do_mount()
  cifs: fix rsize/wsize to be negotiated values
  cifs: Fix some error pointers handling detected by static checker
  smb3: remind users that witness protocol is experimental
  cifs: update super_operations to show_devname
  cifs: fix uninitialized variable in smb3_fs_context_parse_param
  cifs: update mnt_cifs_flags during reconfigure
  cifs: move update of flags into a separate function
  cifs: remove ctx argument from cifs_setup_cifs_sb
  cifs: do not allow changing posix_paths during remount
  cifs: uncomplicate printing the iocharset parameter
  cifs: don't create a temp nls in cifs_setup_ipc
  cifs: simplify handling of cifs_sb/ctx->local_nls
  cifs: we do not allow changing username/password/unc/... during remount
  cifs: add initial reconfigure support
  ...

1 files changed, 694 insertions, 0 deletions

diff --git a/fs/cifs/cifs_swn.c b/fs/cifs/cifs_swn.c
new file mode 100644
index 000000000000..c594e588a8b5
--- /dev/null
+++ b/fs/cifs/cifs_swn.c
@@ -0,0 +1,694 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Witness Service client for CIFS
+ *
+ * Copyright (c) 2020 Samuel Cabrero <scabrero@suse.de>
+ */
+
+#include <linux/kref.h>
+#include <net/genetlink.h>
+#include <uapi/linux/cifs/cifs_netlink.h>
+
+#include "cifs_swn.h"
+#include "cifsglob.h"
+#include "cifsproto.h"
+#include "fscache.h"
+#include "cifs_debug.h"
+#include "netlink.h"
+
+static DEFINE_IDR(cifs_swnreg_idr);
+static DEFINE_MUTEX(cifs_swnreg_idr_mutex);
+
+struct cifs_swn_reg {
+	int id;
+	struct kref ref_count;
+
+	const char *net_name;
+	const char *share_name;
+	bool net_name_notify;
+	bool share_name_notify;
+	bool ip_notify;
+
+	struct cifs_tcon *tcon;
+};
+
+static int cifs_swn_auth_info_krb(struct cifs_tcon *tcon, struct sk_buff *skb)
+{
+	int ret;
+
+	ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_KRB_AUTH);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int cifs_swn_auth_info_ntlm(struct cifs_tcon *tcon, struct sk_buff *skb)
+{
+	int ret;
+
+	if (tcon->ses->user_name != NULL) {
+		ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_USER_NAME, tcon->ses->user_name);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (tcon->ses->password != NULL) {
+		ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_PASSWORD, tcon->ses->password);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (tcon->ses->domainName != NULL) {
+		ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_DOMAIN_NAME, tcon->ses->domainName);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Sends a register message to the userspace daemon based on the registration.
+ * The authentication information to connect to the witness service is bundled
+ * into the message.
+ */
+static int cifs_swn_send_register_message(struct cifs_swn_reg *swnreg)
+{
+	struct sk_buff *skb;
+	struct genlmsghdr *hdr;
+	enum securityEnum authtype;
+	struct sockaddr_storage *addr;
+	int ret;
+
+	skb = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (skb == NULL) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	hdr = genlmsg_put(skb, 0, 0, &cifs_genl_family, 0, CIFS_GENL_CMD_SWN_REGISTER);
+	if (hdr == NULL) {
+		ret = -ENOMEM;
+		goto nlmsg_fail;
+	}
+
+	ret = nla_put_u32(skb, CIFS_GENL_ATTR_SWN_REGISTRATION_ID, swnreg->id);
+	if (ret < 0)
+		goto nlmsg_fail;
+
+	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_NET_NAME, swnreg->net_name);
+	if (ret < 0)
+		goto nlmsg_fail;
+
+	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME, swnreg->share_name);
+	if (ret < 0)
+		goto nlmsg_fail;
+
+	/*
+	 * If there is an address stored use it instead of the server address, because we are
+	 * in the process of reconnecting to it after a share has been moved or we have been
+	 * told to switch to it (client move message). In these cases we unregister from the
+	 * server address and register to the new address when we receive the notification.
+	 */
+	if (swnreg->tcon->ses->server->use_swn_dstaddr)
+		addr = &swnreg->tcon->ses->server->swn_dstaddr;
+	else
+		addr = &swnreg->tcon->ses->server->dstaddr;
+
+	ret = nla_put(skb, CIFS_GENL_ATTR_SWN_IP, sizeof(struct sockaddr_storage), addr);
+	if (ret < 0)
+		goto nlmsg_fail;
+
+	if (swnreg->net_name_notify) {
+		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_NET_NAME_NOTIFY);
+		if (ret < 0)
+			goto nlmsg_fail;
+	}
+
+	if (swnreg->share_name_notify) {
+		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME_NOTIFY);
+		if (ret < 0)
+			goto nlmsg_fail;
+	}
+
+	if (swnreg->ip_notify) {
+		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_IP_NOTIFY);
+		if (ret < 0)
+			goto nlmsg_fail;
+	}
+
+	authtype = cifs_select_sectype(swnreg->tcon->ses->server, swnreg->tcon->ses->sectype);
+	switch (authtype) {
+	case Kerberos:
+		ret = cifs_swn_auth_info_krb(swnreg->tcon, skb);
+		if (ret < 0) {
+			cifs_dbg(VFS, "%s: Failed to get kerberos auth info: %d\n", __func__, ret);
+			goto nlmsg_fail;
+		}
+		break;
+	case LANMAN:
+	case NTLM:
+	case NTLMv2:
+	case RawNTLMSSP:
+		ret = cifs_swn_auth_info_ntlm(swnreg->tcon, skb);
+		if (ret < 0) {
+			cifs_dbg(VFS, "%s: Failed to get NTLM auth info: %d\n", __func__, ret);
+			goto nlmsg_fail;
+		}
+		break;
+	default:
+		cifs_dbg(VFS, "%s: secType %d not supported!\n", __func__, authtype);
+		ret = -EINVAL;
+		goto nlmsg_fail;
+	}
+
+	genlmsg_end(skb, hdr);
+	genlmsg_multicast(&cifs_genl_family, skb, 0, CIFS_GENL_MCGRP_SWN, GFP_ATOMIC);
+
+	cifs_dbg(FYI, "%s: Message to register for network name %s with id %d sent\n", __func__,
+			swnreg->net_name, swnreg->id);
+
+	return 0;
+
+nlmsg_fail:
+	genlmsg_cancel(skb, hdr);
+	nlmsg_free(skb);
+fail:
+	return ret;
+}
+
+/*
+ * Sends an uregister message to the userspace daemon based on the registration
+ */
+static int cifs_swn_send_unregister_message(struct cifs_swn_reg *swnreg)
+{
+	struct sk_buff *skb;
+	struct genlmsghdr *hdr;
+	int ret;
+
+	skb = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (skb == NULL)
+		return -ENOMEM;
+
+	hdr = genlmsg_put(skb, 0, 0, &cifs_genl_family, 0, CIFS_GENL_CMD_SWN_UNREGISTER);
+	if (hdr == NULL) {
+		ret = -ENOMEM;
+		goto nlmsg_fail;
+	}
+
+	ret = nla_put_u32(skb, CIFS_GENL_ATTR_SWN_REGISTRATION_ID, swnreg->id);
+	if (ret < 0)
+		goto nlmsg_fail;
+
+	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_NET_NAME, swnreg->net_name);
+	if (ret < 0)
+		goto nlmsg_fail;
+
+	ret = nla_put_string(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME, swnreg->share_name);
+	if (ret < 0)
+		goto nlmsg_fail;
+
+	ret = nla_put(skb, CIFS_GENL_ATTR_SWN_IP, sizeof(struct sockaddr_storage),
+			&swnreg->tcon->ses->server->dstaddr);
+	if (ret < 0)
+		goto nlmsg_fail;
+
+	if (swnreg->net_name_notify) {
+		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_NET_NAME_NOTIFY);
+		if (ret < 0)
+			goto nlmsg_fail;
+	}
+
+	if (swnreg->share_name_notify) {
+		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_SHARE_NAME_NOTIFY);
+		if (ret < 0)
+			goto nlmsg_fail;
+	}
+
+	if (swnreg->ip_notify) {
+		ret = nla_put_flag(skb, CIFS_GENL_ATTR_SWN_IP_NOTIFY);
+		if (ret < 0)
+			goto nlmsg_fail;
+	}
+
+	genlmsg_end(skb, hdr);
+	genlmsg_multicast(&cifs_genl_family, skb, 0, CIFS_GENL_MCGRP_SWN, GFP_ATOMIC);
+
+	cifs_dbg(FYI, "%s: Message to unregister for network name %s with id %d sent\n", __func__,
+			swnreg->net_name, swnreg->id);
+
+	return 0;
+
+nlmsg_fail:
+	genlmsg_cancel(skb, hdr);
+	nlmsg_free(skb);
+	return ret;
+}
+
+/*
+ * Try to find a matching registration for the tcon's server name and share name.
+ * Calls to this funciton must be protected by cifs_swnreg_idr_mutex.
+ * TODO Try to avoid memory allocations
+ */
+static struct cifs_swn_reg *cifs_find_swn_reg(struct cifs_tcon *tcon)
+{
+	struct cifs_swn_reg *swnreg;
+	int id;
+	const char *share_name;
+	const char *net_name;
+
+	net_name = extract_hostname(tcon->treeName);
+	if (IS_ERR(net_name)) {
+		int ret;
+
+		ret = PTR_ERR(net_name);
+		cifs_dbg(VFS, "%s: failed to extract host name from target '%s': %d\n",
+				__func__, tcon->treeName, ret);
+		return ERR_PTR(-EINVAL);
+	}
+
+	share_name = extract_sharename(tcon->treeName);
+	if (IS_ERR(share_name)) {
+		int ret;
+
+		ret = PTR_ERR(net_name);
+		cifs_dbg(VFS, "%s: failed to extract share name from target '%s': %d\n",
+				__func__, tcon->treeName, ret);
+		kfree(net_name);
+		return ERR_PTR(-EINVAL);
+	}
+
+	idr_for_each_entry(&cifs_swnreg_idr, swnreg, id) {
+		if (strcasecmp(swnreg->net_name, net_name) != 0
+		    || strcasecmp(swnreg->share_name, share_name) != 0) {
+			continue;
+		}
+
+		mutex_unlock(&cifs_swnreg_idr_mutex);
+
+		cifs_dbg(FYI, "Existing swn registration for %s:%s found\n", swnreg->net_name,
+				swnreg->share_name);
+
+		kfree(net_name);
+		kfree(share_name);
+
+		return swnreg;
+	}
+
+	kfree(net_name);
+	kfree(share_name);
+
+	return ERR_PTR(-EEXIST);
+}
+
+/*
+ * Get a registration for the tcon's server and share name, allocating a new one if it does not
+ * exists
+ */
+static struct cifs_swn_reg *cifs_get_swn_reg(struct cifs_tcon *tcon)
+{
+	struct cifs_swn_reg *reg = NULL;
+	int ret;
+
+	mutex_lock(&cifs_swnreg_idr_mutex);
+
+	/* Check if we are already registered for this network and share names */
+	reg = cifs_find_swn_reg(tcon);
+	if (!IS_ERR(reg)) {
+		kref_get(&reg->ref_count);
+		mutex_unlock(&cifs_swnreg_idr_mutex);
+		return reg;
+	} else if (PTR_ERR(reg) != -EEXIST) {
+		mutex_unlock(&cifs_swnreg_idr_mutex);
+		return reg;
+	}
+
+	reg = kmalloc(sizeof(struct cifs_swn_reg), GFP_ATOMIC);
+	if (reg == NULL) {
+		mutex_unlock(&cifs_swnreg_idr_mutex);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	kref_init(&reg->ref_count);
+
+	reg->id = idr_alloc(&cifs_swnreg_idr, reg, 1, 0, GFP_ATOMIC);
+	if (reg->id < 0) {
+		cifs_dbg(FYI, "%s: failed to allocate registration id\n", __func__);
+		ret = reg->id;
+		goto fail;
+	}
+
+	reg->net_name = extract_hostname(tcon->treeName);
+	if (IS_ERR(reg->net_name)) {
+		ret = PTR_ERR(reg->net_name);
+		cifs_dbg(VFS, "%s: failed to extract host name from target: %d\n", __func__, ret);
+		goto fail_idr;
+	}
+
+	reg->share_name = extract_sharename(tcon->treeName);
+	if (IS_ERR(reg->share_name)) {
+		ret = PTR_ERR(reg->share_name);
+		cifs_dbg(VFS, "%s: failed to extract share name from target: %d\n", __func__, ret);
+		goto fail_net_name;
+	}
+
+	reg->net_name_notify = true;
+	reg->share_name_notify = true;
+	reg->ip_notify = (tcon->capabilities & SMB2_SHARE_CAP_SCALEOUT);
+
+	reg->tcon = tcon;
+
+	mutex_unlock(&cifs_swnreg_idr_mutex);
+
+	return reg;
+
+fail_net_name:
+	kfree(reg->net_name);
+fail_idr:
+	idr_remove(&cifs_swnreg_idr, reg->id);
+fail:
+	kfree(reg);
+	mutex_unlock(&cifs_swnreg_idr_mutex);
+	return ERR_PTR(ret);
+}
+
+static void cifs_swn_reg_release(struct kref *ref)
+{
+	struct cifs_swn_reg *swnreg = container_of(ref, struct cifs_swn_reg, ref_count);
+	int ret;
+
+	ret = cifs_swn_send_unregister_message(swnreg);
+	if (ret < 0)
+		cifs_dbg(VFS, "%s: Failed to send unregister message: %d\n", __func__, ret);
+
+	idr_remove(&cifs_swnreg_idr, swnreg->id);
+	kfree(swnreg->net_name);
+	kfree(swnreg->share_name);
+	kfree(swnreg);
+}
+
+static void cifs_put_swn_reg(struct cifs_swn_reg *swnreg)
+{
+	mutex_lock(&cifs_swnreg_idr_mutex);
+	kref_put(&swnreg->ref_count, cifs_swn_reg_release);
+	mutex_unlock(&cifs_swnreg_idr_mutex);
+}
+
+static int cifs_swn_resource_state_changed(struct cifs_swn_reg *swnreg, const char *name, int state)
+{
+	int i;
+
+	switch (state) {
+	case CIFS_SWN_RESOURCE_STATE_UNAVAILABLE:
+		cifs_dbg(FYI, "%s: resource name '%s' become unavailable\n", __func__, name);
+		for (i = 0; i < swnreg->tcon->ses->chan_count; i++) {
+			spin_lock(&GlobalMid_Lock);
+			if (swnreg->tcon->ses->chans[i].server->tcpStatus != CifsExiting)
+				swnreg->tcon->ses->chans[i].server->tcpStatus = CifsNeedReconnect;
+			spin_unlock(&GlobalMid_Lock);
+		}
+		break;
+	case CIFS_SWN_RESOURCE_STATE_AVAILABLE:
+		cifs_dbg(FYI, "%s: resource name '%s' become available\n", __func__, name);
+		for (i = 0; i < swnreg->tcon->ses->chan_count; i++) {
+			spin_lock(&GlobalMid_Lock);
+			if (swnreg->tcon->ses->chans[i].server->tcpStatus != CifsExiting)
+				swnreg->tcon->ses->chans[i].server->tcpStatus = CifsNeedReconnect;
+			spin_unlock(&GlobalMid_Lock);
+		}
+		break;
+	case CIFS_SWN_RESOURCE_STATE_UNKNOWN:
+		cifs_dbg(FYI, "%s: resource name '%s' changed to unknown state\n", __func__, name);
+		break;
+	}
+	return 0;
+}
+
+static bool cifs_sockaddr_equal(struct sockaddr_storage *addr1, struct sockaddr_storage *addr2)
+{
+	if (addr1->ss_family != addr2->ss_family)
+		return false;
+
+	if (addr1->ss_family == AF_INET) {
+		return (memcmp(&((const struct sockaddr_in *)addr1)->sin_addr,
+				&((const struct sockaddr_in *)addr2)->sin_addr,
+				sizeof(struct in_addr)) == 0);
+	}
+
+	if (addr1->ss_family == AF_INET6) {
+		return (memcmp(&((const struct sockaddr_in6 *)addr1)->sin6_addr,
+				&((const struct sockaddr_in6 *)addr2)->sin6_addr,
+				sizeof(struct in6_addr)) == 0);
+	}
+
+	return false;
+}
+
+static int cifs_swn_store_swn_addr(const struct sockaddr_storage *new,
+				   const struct sockaddr_storage *old,
+				   struct sockaddr_storage *dst)
+{
+	__be16 port;
+
+	if (old->ss_family == AF_INET) {
+		struct sockaddr_in *ipv4 = (struct sockaddr_in *)old;
+
+		port = ipv4->sin_port;
+	}
+
+	if (old->ss_family == AF_INET6) {
+		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)old;
+
+		port = ipv6->sin6_port;
+	}
+
+	if (new->ss_family == AF_INET) {
+		struct sockaddr_in *ipv4 = (struct sockaddr_in *)new;
+
+		ipv4->sin_port = port;
+	}
+
+	if (new->ss_family == AF_INET6) {
+		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)new;
+
+		ipv6->sin6_port = port;
+	}
+
+	*dst = *new;
+
+	return 0;
+}
+
+static int cifs_swn_reconnect(struct cifs_tcon *tcon, struct sockaddr_storage *addr)
+{
+	/* Store the reconnect address */
+	mutex_lock(&tcon->ses->server->srv_mutex);
+	if (!cifs_sockaddr_equal(&tcon->ses->server->dstaddr, addr)) {
+		int ret;
+
+		ret = cifs_swn_store_swn_addr(addr, &tcon->ses->server->dstaddr,
+				&tcon->ses->server->swn_dstaddr);
+		if (ret < 0) {
+			cifs_dbg(VFS, "%s: failed to store address: %d\n", __func__, ret);
+			return ret;
+		}
+		tcon->ses->server->use_swn_dstaddr = true;
+
+		/*
+		 * Unregister to stop receiving notifications for the old IP address.
+		 */
+		ret = cifs_swn_unregister(tcon);
+		if (ret < 0) {
+			cifs_dbg(VFS, "%s: Failed to unregister for witness notifications: %d\n",
+					__func__, ret);
+			return ret;
+		}
+
+		/*
+		 * And register to receive notifications for the new IP address now that we have
+		 * stored the new address.
+		 */
+		ret = cifs_swn_register(tcon);
+		if (ret < 0) {
+			cifs_dbg(VFS, "%s: Failed to register for witness notifications: %d\n",
+					__func__, ret);
+			return ret;
+		}
+
+		spin_lock(&GlobalMid_Lock);
+		if (tcon->ses->server->tcpStatus != CifsExiting)
+			tcon->ses->server->tcpStatus = CifsNeedReconnect;
+		spin_unlock(&GlobalMid_Lock);
+	}
+	mutex_unlock(&tcon->ses->server->srv_mutex);
+
+	return 0;
+}
+
+static int cifs_swn_client_move(struct cifs_swn_reg *swnreg, struct sockaddr_storage *addr)
+{
+	struct sockaddr_in *ipv4 = (struct sockaddr_in *)addr;
+	struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)addr;
+
+	if (addr->ss_family == AF_INET)
+		cifs_dbg(FYI, "%s: move to %pI4\n", __func__, &ipv4->sin_addr);
+	else if (addr->ss_family == AF_INET6)
+		cifs_dbg(FYI, "%s: move to %pI6\n", __func__, &ipv6->sin6_addr);
+
+	return cifs_swn_reconnect(swnreg->tcon, addr);
+}
+
+int cifs_swn_notify(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cifs_swn_reg *swnreg;
+	char name[256];
+	int type;
+
+	if (info->attrs[CIFS_GENL_ATTR_SWN_REGISTRATION_ID]) {
+		int swnreg_id;
+
+		swnreg_id = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_REGISTRATION_ID]);
+		mutex_lock(&cifs_swnreg_idr_mutex);
+		swnreg = idr_find(&cifs_swnreg_idr, swnreg_id);
+		mutex_unlock(&cifs_swnreg_idr_mutex);
+		if (swnreg == NULL) {
+			cifs_dbg(FYI, "%s: registration id %d not found\n", __func__, swnreg_id);
+			return -EINVAL;
+		}
+	} else {
+		cifs_dbg(FYI, "%s: missing registration id attribute\n", __func__);
+		return -EINVAL;
+	}
+
+	if (info->attrs[CIFS_GENL_ATTR_SWN_NOTIFICATION_TYPE]) {
+		type = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_NOTIFICATION_TYPE]);
+	} else {
+		cifs_dbg(FYI, "%s: missing notification type attribute\n", __func__);
+		return -EINVAL;
+	}
+
+	switch (type) {
+	case CIFS_SWN_NOTIFICATION_RESOURCE_CHANGE: {
+		int state;
+
+		if (info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_NAME]) {
+			nla_strscpy(name, info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_NAME],
+					sizeof(name));
+		} else {
+			cifs_dbg(FYI, "%s: missing resource name attribute\n", __func__);
+			return -EINVAL;
+		}
+		if (info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_STATE]) {
+			state = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_STATE]);
+		} else {
+			cifs_dbg(FYI, "%s: missing resource state attribute\n", __func__);
+			return -EINVAL;
+		}
+		return cifs_swn_resource_state_changed(swnreg, name, state);
+	}
+	case CIFS_SWN_NOTIFICATION_CLIENT_MOVE: {
+		struct sockaddr_storage addr;
+
+		if (info->attrs[CIFS_GENL_ATTR_SWN_IP]) {
+			nla_memcpy(&addr, info->attrs[CIFS_GENL_ATTR_SWN_IP], sizeof(addr));
+		} else {
+			cifs_dbg(FYI, "%s: missing IP address attribute\n", __func__);
+			return -EINVAL;
+		}
+		return cifs_swn_client_move(swnreg, &addr);
+	}
+	default:
+		cifs_dbg(FYI, "%s: unknown notification type %d\n", __func__, type);
+		break;
+	}
+
+	return 0;
+}
+
+int cifs_swn_register(struct cifs_tcon *tcon)
+{
+	struct cifs_swn_reg *swnreg;
+	int ret;
+
+	swnreg = cifs_get_swn_reg(tcon);
+	if (IS_ERR(swnreg))
+		return PTR_ERR(swnreg);
+
+	ret = cifs_swn_send_register_message(swnreg);
+	if (ret < 0) {
+		cifs_dbg(VFS, "%s: Failed to send swn register message: %d\n", __func__, ret);
+		/* Do not put the swnreg or return error, the echo task will retry */
+	}
+
+	return 0;
+}
+
+int cifs_swn_unregister(struct cifs_tcon *tcon)
+{
+	struct cifs_swn_reg *swnreg;
+
+	mutex_lock(&cifs_swnreg_idr_mutex);
+
+	swnreg = cifs_find_swn_reg(tcon);
+	if (IS_ERR(swnreg)) {
+		mutex_unlock(&cifs_swnreg_idr_mutex);
+		return PTR_ERR(swnreg);
+	}
+
+	mutex_unlock(&cifs_swnreg_idr_mutex);
+
+	cifs_put_swn_reg(swnreg);
+
+	return 0;
+}
+
+void cifs_swn_dump(struct seq_file *m)
+{
+	struct cifs_swn_reg *swnreg;
+	struct sockaddr_in *sa;
+	struct sockaddr_in6 *sa6;
+	int id;
+
+	seq_puts(m, "Witness registrations:");
+
+	mutex_lock(&cifs_swnreg_idr_mutex);
+	idr_for_each_entry(&cifs_swnreg_idr, swnreg, id) {
+		seq_printf(m, "\nId: %u Refs: %u Network name: '%s'%s Share name: '%s'%s Ip address: ",
+				id, kref_read(&swnreg->ref_count),
+				swnreg->net_name, swnreg->net_name_notify ? "(y)" : "(n)",
+				swnreg->share_name, swnreg->share_name_notify ? "(y)" : "(n)");
+		switch (swnreg->tcon->ses->server->dstaddr.ss_family) {
+		case AF_INET:
+			sa = (struct sockaddr_in *) &swnreg->tcon->ses->server->dstaddr;
+			seq_printf(m, "%pI4", &sa->sin_addr.s_addr);
+			break;
+		case AF_INET6:
+			sa6 = (struct sockaddr_in6 *) &swnreg->tcon->ses->server->dstaddr;
+			seq_printf(m, "%pI6", &sa6->sin6_addr.s6_addr);
+			if (sa6->sin6_scope_id)
+				seq_printf(m, "%%%u", sa6->sin6_scope_id);
+			break;
+		default:
+			seq_puts(m, "(unknown)");
+		}
+		seq_printf(m, "%s", swnreg->ip_notify ? "(y)" : "(n)");
+	}
+	mutex_unlock(&cifs_swnreg_idr_mutex);
+	seq_puts(m, "\n");
+}
+
+void cifs_swn_check(void)
+{
+	struct cifs_swn_reg *swnreg;
+	int id;
+	int ret;
+
+	mutex_lock(&cifs_swnreg_idr_mutex);
+	idr_for_each_entry(&cifs_swnreg_idr, swnreg, id) {
+		ret = cifs_swn_send_register_message(swnreg);
+		if (ret < 0)
+			cifs_dbg(FYI, "%s: Failed to send register message: %d\n", __func__, ret);
+	}
+	mutex_unlock(&cifs_swnreg_idr_mutex);
+}