1 files changed, 759 insertions, 0 deletions

diff --git a/fs/afs/vlclient.c b/fs/afs/vlclient.c
new file mode 100644
index 000000000..00fca3c66
--- /dev/null
+++ b/fs/afs/vlclient.c
@@ -0,0 +1,759 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* AFS Volume Location Service client
+ *
+ * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include "afs_fs.h"
+#include "internal.h"
+
+/*
+ * Deliver reply data to a VL.GetEntryByNameU call.
+ */
+static int afs_deliver_vl_get_entry_by_name_u(struct afs_call *call)
+{
+	struct afs_uvldbentry__xdr *uvldb;
+	struct afs_vldb_entry *entry;
+	bool new_only = false;
+	u32 tmp, nr_servers, vlflags;
+	int i, ret;
+
+	_enter("");
+
+	ret = afs_transfer_reply(call);
+	if (ret < 0)
+		return ret;
+
+	/* unmarshall the reply once we've received all of it */
+	uvldb = call->buffer;
+	entry = call->ret_vldb;
+
+	nr_servers = ntohl(uvldb->nServers);
+	if (nr_servers > AFS_NMAXNSERVERS)
+		nr_servers = AFS_NMAXNSERVERS;
+
+	for (i = 0; i < ARRAY_SIZE(uvldb->name) - 1; i++)
+		entry->name[i] = (u8)ntohl(uvldb->name[i]);
+	entry->name[i] = 0;
+	entry->name_len = strlen(entry->name);
+
+	/* If there is a new replication site that we can use, ignore all the
+	 * sites that aren't marked as new.
+	 */
+	for (i = 0; i < nr_servers; i++) {
+		tmp = ntohl(uvldb->serverFlags[i]);
+		if (!(tmp & AFS_VLSF_DONTUSE) &&
+		    (tmp & AFS_VLSF_NEWREPSITE))
+			new_only = true;
+	}
+
+	vlflags = ntohl(uvldb->flags);
+	for (i = 0; i < nr_servers; i++) {
+		struct afs_uuid__xdr *xdr;
+		struct afs_uuid *uuid;
+		int j;
+		int n = entry->nr_servers;
+
+		tmp = ntohl(uvldb->serverFlags[i]);
+		if (tmp & AFS_VLSF_DONTUSE ||
+		    (new_only && !(tmp & AFS_VLSF_NEWREPSITE)))
+			continue;
+		if (tmp & AFS_VLSF_RWVOL) {
+			entry->fs_mask[n] |= AFS_VOL_VTM_RW;
+			if (vlflags & AFS_VLF_BACKEXISTS)
+				entry->fs_mask[n] |= AFS_VOL_VTM_BAK;
+		}
+		if (tmp & AFS_VLSF_ROVOL)
+			entry->fs_mask[n] |= AFS_VOL_VTM_RO;
+		if (!entry->fs_mask[n])
+			continue;
+
+		xdr = &uvldb->serverNumber[i];
+		uuid = (struct afs_uuid *)&entry->fs_server[n];
+		uuid->time_low			= xdr->time_low;
+		uuid->time_mid			= htons(ntohl(xdr->time_mid));
+		uuid->time_hi_and_version	= htons(ntohl(xdr->time_hi_and_version));
+		uuid->clock_seq_hi_and_reserved	= (u8)ntohl(xdr->clock_seq_hi_and_reserved);
+		uuid->clock_seq_low		= (u8)ntohl(xdr->clock_seq_low);
+		for (j = 0; j < 6; j++)
+			uuid->node[j] = (u8)ntohl(xdr->node[j]);
+
+		entry->addr_version[n] = ntohl(uvldb->serverUnique[i]);
+		entry->nr_servers++;
+	}
+
+	for (i = 0; i < AFS_MAXTYPES; i++)
+		entry->vid[i] = ntohl(uvldb->volumeId[i]);
+
+	if (vlflags & AFS_VLF_RWEXISTS)
+		__set_bit(AFS_VLDB_HAS_RW, &entry->flags);
+	if (vlflags & AFS_VLF_ROEXISTS)
+		__set_bit(AFS_VLDB_HAS_RO, &entry->flags);
+	if (vlflags & AFS_VLF_BACKEXISTS)
+		__set_bit(AFS_VLDB_HAS_BAK, &entry->flags);
+
+	if (!(vlflags & (AFS_VLF_RWEXISTS | AFS_VLF_ROEXISTS | AFS_VLF_BACKEXISTS))) {
+		entry->error = -ENOMEDIUM;
+		__set_bit(AFS_VLDB_QUERY_ERROR, &entry->flags);
+	}
+
+	__set_bit(AFS_VLDB_QUERY_VALID, &entry->flags);
+	_leave(" = 0 [done]");
+	return 0;
+}
+
+static void afs_destroy_vl_get_entry_by_name_u(struct afs_call *call)
+{
+	kfree(call->ret_vldb);
+	afs_flat_call_destructor(call);
+}
+
+/*
+ * VL.GetEntryByNameU operation type.
+ */
+static const struct afs_call_type afs_RXVLGetEntryByNameU = {
+	.name		= "VL.GetEntryByNameU",
+	.op		= afs_VL_GetEntryByNameU,
+	.deliver	= afs_deliver_vl_get_entry_by_name_u,
+	.destructor	= afs_destroy_vl_get_entry_by_name_u,
+};
+
+/*
+ * Dispatch a get volume entry by name or ID operation (uuid variant).  If the
+ * volname is a decimal number then it's a volume ID not a volume name.
+ */
+struct afs_vldb_entry *afs_vl_get_entry_by_name_u(struct afs_vl_cursor *vc,
+						  const char *volname,
+						  int volnamesz)
+{
+	struct afs_vldb_entry *entry;
+	struct afs_call *call;
+	struct afs_net *net = vc->cell->net;
+	size_t reqsz, padsz;
+	__be32 *bp;
+
+	_enter("");
+
+	padsz = (4 - (volnamesz & 3)) & 3;
+	reqsz = 8 + volnamesz + padsz;
+
+	entry = kzalloc(sizeof(struct afs_vldb_entry), GFP_KERNEL);
+	if (!entry)
+		return ERR_PTR(-ENOMEM);
+
+	call = afs_alloc_flat_call(net, &afs_RXVLGetEntryByNameU, reqsz,
+				   sizeof(struct afs_uvldbentry__xdr));
+	if (!call) {
+		kfree(entry);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	call->key = vc->key;
+	call->ret_vldb = entry;
+	call->max_lifespan = AFS_VL_MAX_LIFESPAN;
+
+	/* Marshall the parameters */
+	bp = call->request;
+	*bp++ = htonl(VLGETENTRYBYNAMEU);
+	*bp++ = htonl(volnamesz);
+	memcpy(bp, volname, volnamesz);
+	if (padsz > 0)
+		memset((void *)bp + volnamesz, 0, padsz);
+
+	trace_afs_make_vl_call(call);
+	afs_make_call(&vc->ac, call, GFP_KERNEL);
+	return (struct afs_vldb_entry *)afs_wait_for_call_to_complete(call, &vc->ac);
+}
+
+/*
+ * Deliver reply data to a VL.GetAddrsU call.
+ *
+ *	GetAddrsU(IN ListAddrByAttributes *inaddr,
+ *		  OUT afsUUID *uuidp1,
+ *		  OUT uint32_t *uniquifier,
+ *		  OUT uint32_t *nentries,
+ *		  OUT bulkaddrs *blkaddrs);
+ */
+static int afs_deliver_vl_get_addrs_u(struct afs_call *call)
+{
+	struct afs_addr_list *alist;
+	__be32 *bp;
+	u32 uniquifier, nentries, count;
+	int i, ret;
+
+	_enter("{%u,%zu/%u}",
+	       call->unmarshall, iov_iter_count(call->iter), call->count);
+
+	switch (call->unmarshall) {
+	case 0:
+		afs_extract_to_buf(call,
+				   sizeof(struct afs_uuid__xdr) + 3 * sizeof(__be32));
+		call->unmarshall++;
+
+		/* Extract the returned uuid, uniquifier, nentries and
+		 * blkaddrs size */
+		fallthrough;
+	case 1:
+		ret = afs_extract_data(call, true);
+		if (ret < 0)
+			return ret;
+
+		bp = call->buffer + sizeof(struct afs_uuid__xdr);
+		uniquifier	= ntohl(*bp++);
+		nentries	= ntohl(*bp++);
+		count		= ntohl(*bp);
+
+		nentries = min(nentries, count);
+		alist = afs_alloc_addrlist(nentries, FS_SERVICE, AFS_FS_PORT);
+		if (!alist)
+			return -ENOMEM;
+		alist->version = uniquifier;
+		call->ret_alist = alist;
+		call->count = count;
+		call->count2 = nentries;
+		call->unmarshall++;
+
+	more_entries:
+		count = min(call->count, 4U);
+		afs_extract_to_buf(call, count * sizeof(__be32));
+
+		fallthrough;	/* and extract entries */
+	case 2:
+		ret = afs_extract_data(call, call->count > 4);
+		if (ret < 0)
+			return ret;
+
+		alist = call->ret_alist;
+		bp = call->buffer;
+		count = min(call->count, 4U);
+		for (i = 0; i < count; i++)
+			if (alist->nr_addrs < call->count2)
+				afs_merge_fs_addr4(alist, *bp++, AFS_FS_PORT);
+
+		call->count -= count;
+		if (call->count > 0)
+			goto more_entries;
+		call->unmarshall++;
+		break;
+	}
+
+	_leave(" = 0 [done]");
+	return 0;
+}
+
+static void afs_vl_get_addrs_u_destructor(struct afs_call *call)
+{
+	afs_put_addrlist(call->ret_alist);
+	return afs_flat_call_destructor(call);
+}
+
+/*
+ * VL.GetAddrsU operation type.
+ */
+static const struct afs_call_type afs_RXVLGetAddrsU = {
+	.name		= "VL.GetAddrsU",
+	.op		= afs_VL_GetAddrsU,
+	.deliver	= afs_deliver_vl_get_addrs_u,
+	.destructor	= afs_vl_get_addrs_u_destructor,
+};
+
+/*
+ * Dispatch an operation to get the addresses for a server, where the server is
+ * nominated by UUID.
+ */
+struct afs_addr_list *afs_vl_get_addrs_u(struct afs_vl_cursor *vc,
+					 const uuid_t *uuid)
+{
+	struct afs_ListAddrByAttributes__xdr *r;
+	const struct afs_uuid *u = (const struct afs_uuid *)uuid;
+	struct afs_call *call;
+	struct afs_net *net = vc->cell->net;
+	__be32 *bp;
+	int i;
+
+	_enter("");
+
+	call = afs_alloc_flat_call(net, &afs_RXVLGetAddrsU,
+				   sizeof(__be32) + sizeof(struct afs_ListAddrByAttributes__xdr),
+				   sizeof(struct afs_uuid__xdr) + 3 * sizeof(__be32));
+	if (!call)
+		return ERR_PTR(-ENOMEM);
+
+	call->key = vc->key;
+	call->ret_alist = NULL;
+	call->max_lifespan = AFS_VL_MAX_LIFESPAN;
+
+	/* Marshall the parameters */
+	bp = call->request;
+	*bp++ = htonl(VLGETADDRSU);
+	r = (struct afs_ListAddrByAttributes__xdr *)bp;
+	r->Mask		= htonl(AFS_VLADDR_UUID);
+	r->ipaddr	= 0;
+	r->index	= 0;
+	r->spare	= 0;
+	r->uuid.time_low			= u->time_low;
+	r->uuid.time_mid			= htonl(ntohs(u->time_mid));
+	r->uuid.time_hi_and_version		= htonl(ntohs(u->time_hi_and_version));
+	r->uuid.clock_seq_hi_and_reserved 	= htonl(u->clock_seq_hi_and_reserved);
+	r->uuid.clock_seq_low			= htonl(u->clock_seq_low);
+	for (i = 0; i < 6; i++)
+		r->uuid.node[i] = htonl(u->node[i]);
+
+	trace_afs_make_vl_call(call);
+	afs_make_call(&vc->ac, call, GFP_KERNEL);
+	return (struct afs_addr_list *)afs_wait_for_call_to_complete(call, &vc->ac);
+}
+
+/*
+ * Deliver reply data to an VL.GetCapabilities operation.
+ */
+static int afs_deliver_vl_get_capabilities(struct afs_call *call)
+{
+	u32 count;
+	int ret;
+
+	_enter("{%u,%zu/%u}",
+	       call->unmarshall, iov_iter_count(call->iter), call->count);
+
+	switch (call->unmarshall) {
+	case 0:
+		afs_extract_to_tmp(call);
+		call->unmarshall++;
+
+		fallthrough;	/* and extract the capabilities word count */
+	case 1:
+		ret = afs_extract_data(call, true);
+		if (ret < 0)
+			return ret;
+
+		count = ntohl(call->tmp);
+		call->count = count;
+		call->count2 = count;
+
+		call->unmarshall++;
+		afs_extract_discard(call, count * sizeof(__be32));
+
+		fallthrough;	/* and extract capabilities words */
+	case 2:
+		ret = afs_extract_data(call, false);
+		if (ret < 0)
+			return ret;
+
+		/* TODO: Examine capabilities */
+
+		call->unmarshall++;
+		break;
+	}
+
+	_leave(" = 0 [done]");
+	return 0;
+}
+
+static void afs_destroy_vl_get_capabilities(struct afs_call *call)
+{
+	afs_put_vlserver(call->net, call->vlserver);
+	afs_flat_call_destructor(call);
+}
+
+/*
+ * VL.GetCapabilities operation type
+ */
+static const struct afs_call_type afs_RXVLGetCapabilities = {
+	.name		= "VL.GetCapabilities",
+	.op		= afs_VL_GetCapabilities,
+	.deliver	= afs_deliver_vl_get_capabilities,
+	.done		= afs_vlserver_probe_result,
+	.destructor	= afs_destroy_vl_get_capabilities,
+};
+
+/*
+ * Probe a volume server for the capabilities that it supports.  This can
+ * return up to 196 words.
+ *
+ * We use this to probe for service upgrade to determine what the server at the
+ * other end supports.
+ */
+struct afs_call *afs_vl_get_capabilities(struct afs_net *net,
+					 struct afs_addr_cursor *ac,
+					 struct key *key,
+					 struct afs_vlserver *server,
+					 unsigned int server_index)
+{
+	struct afs_call *call;
+	__be32 *bp;
+
+	_enter("");
+
+	call = afs_alloc_flat_call(net, &afs_RXVLGetCapabilities, 1 * 4, 16 * 4);
+	if (!call)
+		return ERR_PTR(-ENOMEM);
+
+	call->key = key;
+	call->vlserver = afs_get_vlserver(server);
+	call->server_index = server_index;
+	call->upgrade = true;
+	call->async = true;
+	call->max_lifespan = AFS_PROBE_MAX_LIFESPAN;
+
+	/* marshall the parameters */
+	bp = call->request;
+	*bp++ = htonl(VLGETCAPABILITIES);
+
+	/* Can't take a ref on server */
+	trace_afs_make_vl_call(call);
+	afs_make_call(ac, call, GFP_KERNEL);
+	return call;
+}
+
+/*
+ * Deliver reply data to a YFSVL.GetEndpoints call.
+ *
+ *	GetEndpoints(IN yfsServerAttributes *attr,
+ *		     OUT opr_uuid *uuid,
+ *		     OUT afs_int32 *uniquifier,
+ *		     OUT endpoints *fsEndpoints,
+ *		     OUT endpoints *volEndpoints)
+ */
+static int afs_deliver_yfsvl_get_endpoints(struct afs_call *call)
+{
+	struct afs_addr_list *alist;
+	__be32 *bp;
+	u32 uniquifier, size;
+	int ret;
+
+	_enter("{%u,%zu,%u}",
+	       call->unmarshall, iov_iter_count(call->iter), call->count2);
+
+	switch (call->unmarshall) {
+	case 0:
+		afs_extract_to_buf(call, sizeof(uuid_t) + 3 * sizeof(__be32));
+		call->unmarshall = 1;
+
+		/* Extract the returned uuid, uniquifier, fsEndpoints count and
+		 * either the first fsEndpoint type or the volEndpoints
+		 * count if there are no fsEndpoints. */
+		fallthrough;
+	case 1:
+		ret = afs_extract_data(call, true);
+		if (ret < 0)
+			return ret;
+
+		bp = call->buffer + sizeof(uuid_t);
+		uniquifier	= ntohl(*bp++);
+		call->count	= ntohl(*bp++);
+		call->count2	= ntohl(*bp); /* Type or next count */
+
+		if (call->count > YFS_MAXENDPOINTS)
+			return afs_protocol_error(call, afs_eproto_yvl_fsendpt_num);
+
+		alist = afs_alloc_addrlist(call->count, FS_SERVICE, AFS_FS_PORT);
+		if (!alist)
+			return -ENOMEM;
+		alist->version = uniquifier;
+		call->ret_alist = alist;
+
+		if (call->count == 0)
+			goto extract_volendpoints;
+
+	next_fsendpoint:
+		switch (call->count2) {
+		case YFS_ENDPOINT_IPV4:
+			size = sizeof(__be32) * (1 + 1 + 1);
+			break;
+		case YFS_ENDPOINT_IPV6:
+			size = sizeof(__be32) * (1 + 4 + 1);
+			break;
+		default:
+			return afs_protocol_error(call, afs_eproto_yvl_fsendpt_type);
+		}
+
+		size += sizeof(__be32);
+		afs_extract_to_buf(call, size);
+		call->unmarshall = 2;
+
+		fallthrough;	/* and extract fsEndpoints[] entries */
+	case 2:
+		ret = afs_extract_data(call, true);
+		if (ret < 0)
+			return ret;
+
+		alist = call->ret_alist;
+		bp = call->buffer;
+		switch (call->count2) {
+		case YFS_ENDPOINT_IPV4:
+			if (ntohl(bp[0]) != sizeof(__be32) * 2)
+				return afs_protocol_error(
+					call, afs_eproto_yvl_fsendpt4_len);
+			afs_merge_fs_addr4(alist, bp[1], ntohl(bp[2]));
+			bp += 3;
+			break;
+		case YFS_ENDPOINT_IPV6:
+			if (ntohl(bp[0]) != sizeof(__be32) * 5)
+				return afs_protocol_error(
+					call, afs_eproto_yvl_fsendpt6_len);
+			afs_merge_fs_addr6(alist, bp + 1, ntohl(bp[5]));
+			bp += 6;
+			break;
+		default:
+			return afs_protocol_error(call, afs_eproto_yvl_fsendpt_type);
+		}
+
+		/* Got either the type of the next entry or the count of
+		 * volEndpoints if no more fsEndpoints.
+		 */
+		call->count2 = ntohl(*bp++);
+
+		call->count--;
+		if (call->count > 0)
+			goto next_fsendpoint;
+
+	extract_volendpoints:
+		/* Extract the list of volEndpoints. */
+		call->count = call->count2;
+		if (!call->count)
+			goto end;
+		if (call->count > YFS_MAXENDPOINTS)
+			return afs_protocol_error(call, afs_eproto_yvl_vlendpt_type);
+
+		afs_extract_to_buf(call, 1 * sizeof(__be32));
+		call->unmarshall = 3;
+
+		/* Extract the type of volEndpoints[0].  Normally we would
+		 * extract the type of the next endpoint when we extract the
+		 * data of the current one, but this is the first...
+		 */
+		fallthrough;
+	case 3:
+		ret = afs_extract_data(call, true);
+		if (ret < 0)
+			return ret;
+
+		bp = call->buffer;
+
+	next_volendpoint:
+		call->count2 = ntohl(*bp++);
+		switch (call->count2) {
+		case YFS_ENDPOINT_IPV4:
+			size = sizeof(__be32) * (1 + 1 + 1);
+			break;
+		case YFS_ENDPOINT_IPV6:
+			size = sizeof(__be32) * (1 + 4 + 1);
+			break;
+		default:
+			return afs_protocol_error(call, afs_eproto_yvl_vlendpt_type);
+		}
+
+		if (call->count > 1)
+			size += sizeof(__be32); /* Get next type too */
+		afs_extract_to_buf(call, size);
+		call->unmarshall = 4;
+
+		fallthrough;	/* and extract volEndpoints[] entries */
+	case 4:
+		ret = afs_extract_data(call, true);
+		if (ret < 0)
+			return ret;
+
+		bp = call->buffer;
+		switch (call->count2) {
+		case YFS_ENDPOINT_IPV4:
+			if (ntohl(bp[0]) != sizeof(__be32) * 2)
+				return afs_protocol_error(
+					call, afs_eproto_yvl_vlendpt4_len);
+			bp += 3;
+			break;
+		case YFS_ENDPOINT_IPV6:
+			if (ntohl(bp[0]) != sizeof(__be32) * 5)
+				return afs_protocol_error(
+					call, afs_eproto_yvl_vlendpt6_len);
+			bp += 6;
+			break;
+		default:
+			return afs_protocol_error(call, afs_eproto_yvl_vlendpt_type);
+		}
+
+		/* Got either the type of the next entry or the count of
+		 * volEndpoints if no more fsEndpoints.
+		 */
+		call->count--;
+		if (call->count > 0)
+			goto next_volendpoint;
+
+	end:
+		afs_extract_discard(call, 0);
+		call->unmarshall = 5;
+
+		fallthrough;	/* Done */
+	case 5:
+		ret = afs_extract_data(call, false);
+		if (ret < 0)
+			return ret;
+		call->unmarshall = 6;
+		fallthrough;
+
+	case 6:
+		break;
+	}
+
+	_leave(" = 0 [done]");
+	return 0;
+}
+
+/*
+ * YFSVL.GetEndpoints operation type.
+ */
+static const struct afs_call_type afs_YFSVLGetEndpoints = {
+	.name		= "YFSVL.GetEndpoints",
+	.op		= afs_YFSVL_GetEndpoints,
+	.deliver	= afs_deliver_yfsvl_get_endpoints,
+	.destructor	= afs_vl_get_addrs_u_destructor,
+};
+
+/*
+ * Dispatch an operation to get the addresses for a server, where the server is
+ * nominated by UUID.
+ */
+struct afs_addr_list *afs_yfsvl_get_endpoints(struct afs_vl_cursor *vc,
+					      const uuid_t *uuid)
+{
+	struct afs_call *call;
+	struct afs_net *net = vc->cell->net;
+	__be32 *bp;
+
+	_enter("");
+
+	call = afs_alloc_flat_call(net, &afs_YFSVLGetEndpoints,
+				   sizeof(__be32) * 2 + sizeof(*uuid),
+				   sizeof(struct in6_addr) + sizeof(__be32) * 3);
+	if (!call)
+		return ERR_PTR(-ENOMEM);
+
+	call->key = vc->key;
+	call->ret_alist = NULL;
+	call->max_lifespan = AFS_VL_MAX_LIFESPAN;
+
+	/* Marshall the parameters */
+	bp = call->request;
+	*bp++ = htonl(YVLGETENDPOINTS);
+	*bp++ = htonl(YFS_SERVER_UUID);
+	memcpy(bp, uuid, sizeof(*uuid)); /* Type opr_uuid */
+
+	trace_afs_make_vl_call(call);
+	afs_make_call(&vc->ac, call, GFP_KERNEL);
+	return (struct afs_addr_list *)afs_wait_for_call_to_complete(call, &vc->ac);
+}
+
+/*
+ * Deliver reply data to a YFSVL.GetCellName operation.
+ */
+static int afs_deliver_yfsvl_get_cell_name(struct afs_call *call)
+{
+	char *cell_name;
+	u32 namesz, paddedsz;
+	int ret;
+
+	_enter("{%u,%zu/%u}",
+	       call->unmarshall, iov_iter_count(call->iter), call->count);
+
+	switch (call->unmarshall) {
+	case 0:
+		afs_extract_to_tmp(call);
+		call->unmarshall++;
+
+		fallthrough;	/* and extract the cell name length */
+	case 1:
+		ret = afs_extract_data(call, true);
+		if (ret < 0)
+			return ret;
+
+		namesz = ntohl(call->tmp);
+		if (namesz > AFS_MAXCELLNAME)
+			return afs_protocol_error(call, afs_eproto_cellname_len);
+		paddedsz = (namesz + 3) & ~3;
+		call->count = namesz;
+		call->count2 = paddedsz - namesz;
+
+		cell_name = kmalloc(namesz + 1, GFP_KERNEL);
+		if (!cell_name)
+			return -ENOMEM;
+		cell_name[namesz] = 0;
+		call->ret_str = cell_name;
+
+		afs_extract_begin(call, cell_name, namesz);
+		call->unmarshall++;
+
+		fallthrough;	/* and extract cell name */
+	case 2:
+		ret = afs_extract_data(call, true);
+		if (ret < 0)
+			return ret;
+
+		afs_extract_discard(call, call->count2);
+		call->unmarshall++;
+
+		fallthrough;	/* and extract padding */
+	case 3:
+		ret = afs_extract_data(call, false);
+		if (ret < 0)
+			return ret;
+
+		call->unmarshall++;
+		break;
+	}
+
+	_leave(" = 0 [done]");
+	return 0;
+}
+
+static void afs_destroy_yfsvl_get_cell_name(struct afs_call *call)
+{
+	kfree(call->ret_str);
+	afs_flat_call_destructor(call);
+}
+
+/*
+ * VL.GetCapabilities operation type
+ */
+static const struct afs_call_type afs_YFSVLGetCellName = {
+	.name		= "YFSVL.GetCellName",
+	.op		= afs_YFSVL_GetCellName,
+	.deliver	= afs_deliver_yfsvl_get_cell_name,
+	.destructor	= afs_destroy_yfsvl_get_cell_name,
+};
+
+/*
+ * Probe a volume server for the capabilities that it supports.  This can
+ * return up to 196 words.
+ *
+ * We use this to probe for service upgrade to determine what the server at the
+ * other end supports.
+ */
+char *afs_yfsvl_get_cell_name(struct afs_vl_cursor *vc)
+{
+	struct afs_call *call;
+	struct afs_net *net = vc->cell->net;
+	__be32 *bp;
+
+	_enter("");
+
+	call = afs_alloc_flat_call(net, &afs_YFSVLGetCellName, 1 * 4, 0);
+	if (!call)
+		return ERR_PTR(-ENOMEM);
+
+	call->key = vc->key;
+	call->ret_str = NULL;
+	call->max_lifespan = AFS_VL_MAX_LIFESPAN;
+
+	/* marshall the parameters */
+	bp = call->request;
+	*bp++ = htonl(YVLGETCELLNAME);
+
+	/* Can't take a ref on server */
+	trace_afs_make_vl_call(call);
+	afs_make_call(&vc->ac, call, GFP_KERNEL);
+	return (char *)afs_wait_for_call_to_complete(call, &vc->ac);
+}