Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 793 insertions, 0 deletions

diff --git a/fs/afs/vlclient.c b/fs/afs/vlclient.c
new file mode 100644
index 000000000..a40b43464
--- /dev/null
+++ b/fs/afs/vlclient.c
@@ -0,0 +1,793 @@
+// 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;
+	u32 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);
+
+	vlflags = ntohl(uvldb->flags);
+	for (i = 0; i < nr_servers; i++) {
+		struct afs_uuid__xdr *xdr;
+		struct afs_uuid *uuid;
+		u32 tmp = ntohl(uvldb->serverFlags[i]);
+		int j;
+		int n = entry->nr_servers;
+
+		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->vlsf_flags[n] = tmp;
+		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;
+}
+
+/*
+ * 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_flat_call_destructor,
+};
+
+/*
+ * 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_obj(struct afs_vldb_entry);
+	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;
+	call->peer = rxrpc_kernel_get_peer(vc->alist->addrs[vc->addr_index].peer);
+	call->service_id = vc->server->service_id;
+
+	/* 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(call, GFP_KERNEL);
+	afs_wait_for_call_to_complete(call);
+	vc->call_abort_code	= call->abort_code;
+	vc->call_error		= call->error;
+	vc->call_responded	= call->responded;
+	afs_put_call(call);
+	if (vc->call_error) {
+		kfree(entry);
+		return ERR_PTR(vc->call_error);
+	}
+	return entry;
+}
+
+/*
+ * 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);
+		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) {
+				ret = afs_merge_fs_addr4(call->net, alist, *bp++, AFS_FS_PORT);
+				if (ret < 0)
+					return ret;
+			}
+		}
+
+		call->count -= count;
+		if (call->count > 0)
+			goto more_entries;
+		call->unmarshall++;
+		break;
+	}
+
+	_leave(" = 0 [done]");
+	return 0;
+}
+
+/*
+ * 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_flat_call_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;
+	struct afs_addr_list *alist;
+	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;
+	call->peer = rxrpc_kernel_get_peer(vc->alist->addrs[vc->addr_index].peer);
+	call->service_id = vc->server->service_id;
+
+	/* 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(call, GFP_KERNEL);
+	afs_wait_for_call_to_complete(call);
+	vc->call_abort_code	= call->abort_code;
+	vc->call_error		= call->error;
+	vc->call_responded	= call->responded;
+	alist			= call->ret_alist;
+	afs_put_call(call);
+	if (vc->call_error) {
+		afs_put_addrlist(alist, afs_alist_trace_put_getaddru);
+		return ERR_PTR(vc->call_error);
+	}
+	return alist;
+}
+
+/*
+ * 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_addrlist(call->vl_probe, afs_alist_trace_put_vlgetcaps);
+	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,
+	.immediate_cancel = afs_vlserver_probe_result,
+	.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_list *alist,
+					 unsigned int addr_index,
+					 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->peer = rxrpc_kernel_get_peer(alist->addrs[addr_index].peer);
+	call->vl_probe = afs_get_addrlist(alist, afs_alist_trace_get_vlgetcaps);
+	call->probe_index = addr_index;
+	call->service_id = server->service_id;
+	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(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);
+		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);
+			ret = afs_merge_fs_addr4(call->net, alist, bp[1], ntohl(bp[2]));
+			if (ret < 0)
+				return ret;
+			bp += 3;
+			break;
+		case YFS_ENDPOINT_IPV6:
+			if (ntohl(bp[0]) != sizeof(__be32) * 5)
+				return afs_protocol_error(
+					call, afs_eproto_yvl_fsendpt6_len);
+			ret = afs_merge_fs_addr6(call->net, alist, bp + 1, ntohl(bp[5]));
+			if (ret < 0)
+				return ret;
+			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_flat_call_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_addr_list *alist;
+	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;
+	call->peer = rxrpc_kernel_get_peer(vc->alist->addrs[vc->addr_index].peer);
+	call->service_id = vc->server->service_id;
+
+	/* 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(call, GFP_KERNEL);
+	afs_wait_for_call_to_complete(call);
+	vc->call_abort_code	= call->abort_code;
+	vc->call_error		= call->error;
+	vc->call_responded	= call->responded;
+	alist			= call->ret_alist;
+	afs_put_call(call);
+	if (vc->call_error) {
+		afs_put_addrlist(alist, afs_alist_trace_put_getaddru);
+		return ERR_PTR(vc->call_error);
+	}
+	return alist;
+}
+
+/*
+ * 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 > YFS_VL_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;
+}
+
+/*
+ * 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_flat_call_destructor,
+};
+
+/*
+ * 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;
+	char *cellname;
+
+	_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;
+	call->peer = rxrpc_kernel_get_peer(vc->alist->addrs[vc->addr_index].peer);
+	call->service_id = vc->server->service_id;
+
+	/* 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(call, GFP_KERNEL);
+	afs_wait_for_call_to_complete(call);
+	vc->call_abort_code	= call->abort_code;
+	vc->call_error		= call->error;
+	vc->call_responded	= call->responded;
+	cellname		= call->ret_str;
+	afs_put_call(call);
+	if (vc->call_error) {
+		kfree(cellname);
+		return ERR_PTR(vc->call_error);
+	}
+	return cellname;
+}