Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 971 insertions, 0 deletions

diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
new file mode 100644
index 000000000..bd6190d79
--- /dev/null
+++ b/fs/nfs/pnfs_nfs.c
@@ -0,0 +1,971 @@
+/*
+ * Common NFS I/O  operations for the pnfs file based
+ * layout drivers.
+ *
+ * Copyright (c) 2014, Primary Data, Inc. All rights reserved.
+ *
+ * Tom Haynes <loghyr@primarydata.com>
+ */
+
+#include <linux/nfs_fs.h>
+#include <linux/nfs_page.h>
+#include <linux/sunrpc/addr.h>
+#include <linux/module.h>
+
+#include "nfs4session.h"
+#include "internal.h"
+#include "pnfs.h"
+
+#define NFSDBG_FACILITY		NFSDBG_PNFS
+
+void pnfs_generic_rw_release(void *data)
+{
+	struct nfs_pgio_header *hdr = data;
+
+	nfs_put_client(hdr->ds_clp);
+	hdr->mds_ops->rpc_release(data);
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_rw_release);
+
+/* Fake up some data that will cause nfs_commit_release to retry the writes. */
+void pnfs_generic_prepare_to_resend_writes(struct nfs_commit_data *data)
+{
+	struct nfs_writeverf *verf = data->res.verf;
+
+	data->task.tk_status = 0;
+	memset(&verf->verifier, 0, sizeof(verf->verifier));
+	verf->committed = NFS_UNSTABLE;
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_prepare_to_resend_writes);
+
+void pnfs_generic_write_commit_done(struct rpc_task *task, void *data)
+{
+	struct nfs_commit_data *wdata = data;
+
+	/* Note this may cause RPC to be resent */
+	wdata->mds_ops->rpc_call_done(task, data);
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_write_commit_done);
+
+void pnfs_generic_commit_release(void *calldata)
+{
+	struct nfs_commit_data *data = calldata;
+
+	data->completion_ops->completion(data);
+	pnfs_put_lseg(data->lseg);
+	nfs_put_client(data->ds_clp);
+	nfs_commitdata_release(data);
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_commit_release);
+
+/* The generic layer is about to remove the req from the commit list.
+ * If this will make the bucket empty, it will need to put the lseg reference.
+ * Note this must be called holding nfsi->commit_mutex
+ */
+void
+pnfs_generic_clear_request_commit(struct nfs_page *req,
+				  struct nfs_commit_info *cinfo)
+{
+	struct pnfs_layout_segment *freeme = NULL;
+
+	if (!test_and_clear_bit(PG_COMMIT_TO_DS, &req->wb_flags))
+		goto out;
+	cinfo->ds->nwritten--;
+	if (list_is_singular(&req->wb_list)) {
+		struct pnfs_commit_bucket *bucket;
+
+		bucket = list_first_entry(&req->wb_list,
+					  struct pnfs_commit_bucket,
+					  written);
+		freeme = bucket->wlseg;
+		bucket->wlseg = NULL;
+	}
+out:
+	nfs_request_remove_commit_list(req, cinfo);
+	pnfs_put_lseg(freeme);
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_clear_request_commit);
+
+static int
+pnfs_generic_scan_ds_commit_list(struct pnfs_commit_bucket *bucket,
+				 struct nfs_commit_info *cinfo,
+				 int max)
+{
+	struct list_head *src = &bucket->written;
+	struct list_head *dst = &bucket->committing;
+	int ret;
+
+	lockdep_assert_held(&NFS_I(cinfo->inode)->commit_mutex);
+	ret = nfs_scan_commit_list(src, dst, cinfo, max);
+	if (ret) {
+		cinfo->ds->nwritten -= ret;
+		cinfo->ds->ncommitting += ret;
+		if (bucket->clseg == NULL)
+			bucket->clseg = pnfs_get_lseg(bucket->wlseg);
+		if (list_empty(src)) {
+			pnfs_put_lseg(bucket->wlseg);
+			bucket->wlseg = NULL;
+		}
+	}
+	return ret;
+}
+
+/* Move reqs from written to committing lists, returning count
+ * of number moved.
+ */
+int pnfs_generic_scan_commit_lists(struct nfs_commit_info *cinfo,
+				   int max)
+{
+	int i, rv = 0, cnt;
+
+	lockdep_assert_held(&NFS_I(cinfo->inode)->commit_mutex);
+	for (i = 0; i < cinfo->ds->nbuckets && max != 0; i++) {
+		cnt = pnfs_generic_scan_ds_commit_list(&cinfo->ds->buckets[i],
+						       cinfo, max);
+		max -= cnt;
+		rv += cnt;
+	}
+	return rv;
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_scan_commit_lists);
+
+/* Pull everything off the committing lists and dump into @dst.  */
+void pnfs_generic_recover_commit_reqs(struct list_head *dst,
+				      struct nfs_commit_info *cinfo)
+{
+	struct pnfs_commit_bucket *b;
+	struct pnfs_layout_segment *freeme;
+	int nwritten;
+	int i;
+
+	lockdep_assert_held(&NFS_I(cinfo->inode)->commit_mutex);
+restart:
+	for (i = 0, b = cinfo->ds->buckets; i < cinfo->ds->nbuckets; i++, b++) {
+		nwritten = nfs_scan_commit_list(&b->written, dst, cinfo, 0);
+		if (!nwritten)
+			continue;
+		cinfo->ds->nwritten -= nwritten;
+		if (list_empty(&b->written)) {
+			freeme = b->wlseg;
+			b->wlseg = NULL;
+			pnfs_put_lseg(freeme);
+			goto restart;
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_recover_commit_reqs);
+
+static void pnfs_generic_retry_commit(struct nfs_commit_info *cinfo, int idx)
+{
+	struct pnfs_ds_commit_info *fl_cinfo = cinfo->ds;
+	struct pnfs_commit_bucket *bucket;
+	struct pnfs_layout_segment *freeme;
+	struct list_head *pos;
+	LIST_HEAD(pages);
+	int i;
+
+	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
+	for (i = idx; i < fl_cinfo->nbuckets; i++) {
+		bucket = &fl_cinfo->buckets[i];
+		if (list_empty(&bucket->committing))
+			continue;
+		freeme = bucket->clseg;
+		bucket->clseg = NULL;
+		list_for_each(pos, &bucket->committing)
+			cinfo->ds->ncommitting--;
+		list_splice_init(&bucket->committing, &pages);
+		mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
+		nfs_retry_commit(&pages, freeme, cinfo, i);
+		pnfs_put_lseg(freeme);
+		mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
+	}
+	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
+}
+
+static unsigned int
+pnfs_generic_alloc_ds_commits(struct nfs_commit_info *cinfo,
+			      struct list_head *list)
+{
+	struct pnfs_ds_commit_info *fl_cinfo;
+	struct pnfs_commit_bucket *bucket;
+	struct nfs_commit_data *data;
+	int i;
+	unsigned int nreq = 0;
+
+	fl_cinfo = cinfo->ds;
+	bucket = fl_cinfo->buckets;
+	for (i = 0; i < fl_cinfo->nbuckets; i++, bucket++) {
+		if (list_empty(&bucket->committing))
+			continue;
+		data = nfs_commitdata_alloc(false);
+		if (!data)
+			break;
+		data->ds_commit_index = i;
+		list_add(&data->pages, list);
+		nreq++;
+	}
+
+	/* Clean up on error */
+	pnfs_generic_retry_commit(cinfo, i);
+	return nreq;
+}
+
+static inline
+void pnfs_fetch_commit_bucket_list(struct list_head *pages,
+		struct nfs_commit_data *data,
+		struct nfs_commit_info *cinfo)
+{
+	struct pnfs_commit_bucket *bucket;
+	struct list_head *pos;
+
+	bucket = &cinfo->ds->buckets[data->ds_commit_index];
+	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
+	list_for_each(pos, &bucket->committing)
+		cinfo->ds->ncommitting--;
+	list_splice_init(&bucket->committing, pages);
+	data->lseg = bucket->clseg;
+	bucket->clseg = NULL;
+	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
+
+}
+
+/* Helper function for pnfs_generic_commit_pagelist to catch an empty
+ * page list. This can happen when two commits race.
+ *
+ * This must be called instead of nfs_init_commit - call one or the other, but
+ * not both!
+ */
+static bool
+pnfs_generic_commit_cancel_empty_pagelist(struct list_head *pages,
+					  struct nfs_commit_data *data,
+					  struct nfs_commit_info *cinfo)
+{
+	if (list_empty(pages)) {
+		if (atomic_dec_and_test(&cinfo->mds->rpcs_out))
+			wake_up_var(&cinfo->mds->rpcs_out);
+		/* don't call nfs_commitdata_release - it tries to put
+		 * the open_context which is not acquired until nfs_init_commit
+		 * which has not been called on @data */
+		WARN_ON_ONCE(data->context);
+		nfs_commit_free(data);
+		return true;
+	}
+
+	return false;
+}
+
+/* This follows nfs_commit_list pretty closely */
+int
+pnfs_generic_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
+			     int how, struct nfs_commit_info *cinfo,
+			     int (*initiate_commit)(struct nfs_commit_data *data,
+						    int how))
+{
+	struct nfs_commit_data *data, *tmp;
+	LIST_HEAD(list);
+	unsigned int nreq = 0;
+
+	if (!list_empty(mds_pages)) {
+		data = nfs_commitdata_alloc(true);
+		data->ds_commit_index = -1;
+		list_add(&data->pages, &list);
+		nreq++;
+	}
+
+	nreq += pnfs_generic_alloc_ds_commits(cinfo, &list);
+
+	if (nreq == 0)
+		goto out;
+
+	atomic_add(nreq, &cinfo->mds->rpcs_out);
+
+	list_for_each_entry_safe(data, tmp, &list, pages) {
+		list_del_init(&data->pages);
+		if (data->ds_commit_index < 0) {
+			/* another commit raced with us */
+			if (pnfs_generic_commit_cancel_empty_pagelist(mds_pages,
+				data, cinfo))
+				continue;
+
+			nfs_init_commit(data, mds_pages, NULL, cinfo);
+			nfs_initiate_commit(NFS_CLIENT(inode), data,
+					    NFS_PROTO(data->inode),
+					    data->mds_ops, how, 0);
+		} else {
+			LIST_HEAD(pages);
+
+			pnfs_fetch_commit_bucket_list(&pages, data, cinfo);
+
+			/* another commit raced with us */
+			if (pnfs_generic_commit_cancel_empty_pagelist(&pages,
+				data, cinfo))
+				continue;
+
+			nfs_init_commit(data, &pages, data->lseg, cinfo);
+			initiate_commit(data, how);
+		}
+	}
+out:
+	return PNFS_ATTEMPTED;
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_commit_pagelist);
+
+/*
+ * Data server cache
+ *
+ * Data servers can be mapped to different device ids.
+ * nfs4_pnfs_ds reference counting
+ *   - set to 1 on allocation
+ *   - incremented when a device id maps a data server already in the cache.
+ *   - decremented when deviceid is removed from the cache.
+ */
+static DEFINE_SPINLOCK(nfs4_ds_cache_lock);
+static LIST_HEAD(nfs4_data_server_cache);
+
+/* Debug routines */
+static void
+print_ds(struct nfs4_pnfs_ds *ds)
+{
+	if (ds == NULL) {
+		printk(KERN_WARNING "%s NULL device\n", __func__);
+		return;
+	}
+	printk(KERN_WARNING "        ds %s\n"
+		"        ref count %d\n"
+		"        client %p\n"
+		"        cl_exchange_flags %x\n",
+		ds->ds_remotestr,
+		refcount_read(&ds->ds_count), ds->ds_clp,
+		ds->ds_clp ? ds->ds_clp->cl_exchange_flags : 0);
+}
+
+static bool
+same_sockaddr(struct sockaddr *addr1, struct sockaddr *addr2)
+{
+	struct sockaddr_in *a, *b;
+	struct sockaddr_in6 *a6, *b6;
+
+	if (addr1->sa_family != addr2->sa_family)
+		return false;
+
+	switch (addr1->sa_family) {
+	case AF_INET:
+		a = (struct sockaddr_in *)addr1;
+		b = (struct sockaddr_in *)addr2;
+
+		if (a->sin_addr.s_addr == b->sin_addr.s_addr &&
+		    a->sin_port == b->sin_port)
+			return true;
+		break;
+
+	case AF_INET6:
+		a6 = (struct sockaddr_in6 *)addr1;
+		b6 = (struct sockaddr_in6 *)addr2;
+
+		/* LINKLOCAL addresses must have matching scope_id */
+		if (ipv6_addr_src_scope(&a6->sin6_addr) ==
+		    IPV6_ADDR_SCOPE_LINKLOCAL &&
+		    a6->sin6_scope_id != b6->sin6_scope_id)
+			return false;
+
+		if (ipv6_addr_equal(&a6->sin6_addr, &b6->sin6_addr) &&
+		    a6->sin6_port == b6->sin6_port)
+			return true;
+		break;
+
+	default:
+		dprintk("%s: unhandled address family: %u\n",
+			__func__, addr1->sa_family);
+		return false;
+	}
+
+	return false;
+}
+
+/*
+ * Checks if 'dsaddrs1' contains a subset of 'dsaddrs2'. If it does,
+ * declare a match.
+ */
+static bool
+_same_data_server_addrs_locked(const struct list_head *dsaddrs1,
+			       const struct list_head *dsaddrs2)
+{
+	struct nfs4_pnfs_ds_addr *da1, *da2;
+	struct sockaddr *sa1, *sa2;
+	bool match = false;
+
+	list_for_each_entry(da1, dsaddrs1, da_node) {
+		sa1 = (struct sockaddr *)&da1->da_addr;
+		match = false;
+		list_for_each_entry(da2, dsaddrs2, da_node) {
+			sa2 = (struct sockaddr *)&da2->da_addr;
+			match = same_sockaddr(sa1, sa2);
+			if (match)
+				break;
+		}
+		if (!match)
+			break;
+	}
+	return match;
+}
+
+/*
+ * Lookup DS by addresses.  nfs4_ds_cache_lock is held
+ */
+static struct nfs4_pnfs_ds *
+_data_server_lookup_locked(const struct list_head *dsaddrs)
+{
+	struct nfs4_pnfs_ds *ds;
+
+	list_for_each_entry(ds, &nfs4_data_server_cache, ds_node)
+		if (_same_data_server_addrs_locked(&ds->ds_addrs, dsaddrs))
+			return ds;
+	return NULL;
+}
+
+static void destroy_ds(struct nfs4_pnfs_ds *ds)
+{
+	struct nfs4_pnfs_ds_addr *da;
+
+	dprintk("--> %s\n", __func__);
+	ifdebug(FACILITY)
+		print_ds(ds);
+
+	nfs_put_client(ds->ds_clp);
+
+	while (!list_empty(&ds->ds_addrs)) {
+		da = list_first_entry(&ds->ds_addrs,
+				      struct nfs4_pnfs_ds_addr,
+				      da_node);
+		list_del_init(&da->da_node);
+		kfree(da->da_remotestr);
+		kfree(da);
+	}
+
+	kfree(ds->ds_remotestr);
+	kfree(ds);
+}
+
+void nfs4_pnfs_ds_put(struct nfs4_pnfs_ds *ds)
+{
+	if (refcount_dec_and_lock(&ds->ds_count,
+				&nfs4_ds_cache_lock)) {
+		list_del_init(&ds->ds_node);
+		spin_unlock(&nfs4_ds_cache_lock);
+		destroy_ds(ds);
+	}
+}
+EXPORT_SYMBOL_GPL(nfs4_pnfs_ds_put);
+
+/*
+ * Create a string with a human readable address and port to avoid
+ * complicated setup around many dprinks.
+ */
+static char *
+nfs4_pnfs_remotestr(struct list_head *dsaddrs, gfp_t gfp_flags)
+{
+	struct nfs4_pnfs_ds_addr *da;
+	char *remotestr;
+	size_t len;
+	char *p;
+
+	len = 3;        /* '{', '}' and eol */
+	list_for_each_entry(da, dsaddrs, da_node) {
+		len += strlen(da->da_remotestr) + 1;    /* string plus comma */
+	}
+
+	remotestr = kzalloc(len, gfp_flags);
+	if (!remotestr)
+		return NULL;
+
+	p = remotestr;
+	*(p++) = '{';
+	len--;
+	list_for_each_entry(da, dsaddrs, da_node) {
+		size_t ll = strlen(da->da_remotestr);
+
+		if (ll > len)
+			goto out_err;
+
+		memcpy(p, da->da_remotestr, ll);
+		p += ll;
+		len -= ll;
+
+		if (len < 1)
+			goto out_err;
+		(*p++) = ',';
+		len--;
+	}
+	if (len < 2)
+		goto out_err;
+	*(p++) = '}';
+	*p = '\0';
+	return remotestr;
+out_err:
+	kfree(remotestr);
+	return NULL;
+}
+
+/*
+ * Given a list of multipath struct nfs4_pnfs_ds_addr, add it to ds cache if
+ * uncached and return cached struct nfs4_pnfs_ds.
+ */
+struct nfs4_pnfs_ds *
+nfs4_pnfs_ds_add(struct list_head *dsaddrs, gfp_t gfp_flags)
+{
+	struct nfs4_pnfs_ds *tmp_ds, *ds = NULL;
+	char *remotestr;
+
+	if (list_empty(dsaddrs)) {
+		dprintk("%s: no addresses defined\n", __func__);
+		goto out;
+	}
+
+	ds = kzalloc(sizeof(*ds), gfp_flags);
+	if (!ds)
+		goto out;
+
+	/* this is only used for debugging, so it's ok if its NULL */
+	remotestr = nfs4_pnfs_remotestr(dsaddrs, gfp_flags);
+
+	spin_lock(&nfs4_ds_cache_lock);
+	tmp_ds = _data_server_lookup_locked(dsaddrs);
+	if (tmp_ds == NULL) {
+		INIT_LIST_HEAD(&ds->ds_addrs);
+		list_splice_init(dsaddrs, &ds->ds_addrs);
+		ds->ds_remotestr = remotestr;
+		refcount_set(&ds->ds_count, 1);
+		INIT_LIST_HEAD(&ds->ds_node);
+		ds->ds_clp = NULL;
+		list_add(&ds->ds_node, &nfs4_data_server_cache);
+		dprintk("%s add new data server %s\n", __func__,
+			ds->ds_remotestr);
+	} else {
+		kfree(remotestr);
+		kfree(ds);
+		refcount_inc(&tmp_ds->ds_count);
+		dprintk("%s data server %s found, inc'ed ds_count to %d\n",
+			__func__, tmp_ds->ds_remotestr,
+			refcount_read(&tmp_ds->ds_count));
+		ds = tmp_ds;
+	}
+	spin_unlock(&nfs4_ds_cache_lock);
+out:
+	return ds;
+}
+EXPORT_SYMBOL_GPL(nfs4_pnfs_ds_add);
+
+static int nfs4_wait_ds_connect(struct nfs4_pnfs_ds *ds)
+{
+	might_sleep();
+	return wait_on_bit(&ds->ds_state, NFS4DS_CONNECTING, TASK_KILLABLE);
+}
+
+static void nfs4_clear_ds_conn_bit(struct nfs4_pnfs_ds *ds)
+{
+	smp_mb__before_atomic();
+	clear_and_wake_up_bit(NFS4DS_CONNECTING, &ds->ds_state);
+}
+
+static struct nfs_client *(*get_v3_ds_connect)(
+			struct nfs_server *mds_srv,
+			const struct sockaddr *ds_addr,
+			int ds_addrlen,
+			int ds_proto,
+			unsigned int ds_timeo,
+			unsigned int ds_retrans);
+
+static bool load_v3_ds_connect(void)
+{
+	if (!get_v3_ds_connect) {
+		get_v3_ds_connect = symbol_request(nfs3_set_ds_client);
+		WARN_ON_ONCE(!get_v3_ds_connect);
+	}
+
+	return(get_v3_ds_connect != NULL);
+}
+
+void nfs4_pnfs_v3_ds_connect_unload(void)
+{
+	if (get_v3_ds_connect) {
+		symbol_put(nfs3_set_ds_client);
+		get_v3_ds_connect = NULL;
+	}
+}
+
+static int _nfs4_pnfs_v3_ds_connect(struct nfs_server *mds_srv,
+				 struct nfs4_pnfs_ds *ds,
+				 unsigned int timeo,
+				 unsigned int retrans)
+{
+	struct nfs_client *clp = ERR_PTR(-EIO);
+	struct nfs4_pnfs_ds_addr *da;
+	int status = 0;
+
+	dprintk("--> %s DS %s\n", __func__, ds->ds_remotestr);
+
+	if (!load_v3_ds_connect())
+		goto out;
+
+	list_for_each_entry(da, &ds->ds_addrs, da_node) {
+		dprintk("%s: DS %s: trying address %s\n",
+			__func__, ds->ds_remotestr, da->da_remotestr);
+
+		if (!IS_ERR(clp)) {
+			struct xprt_create xprt_args = {
+				.ident = XPRT_TRANSPORT_TCP,
+				.net = clp->cl_net,
+				.dstaddr = (struct sockaddr *)&da->da_addr,
+				.addrlen = da->da_addrlen,
+				.servername = clp->cl_hostname,
+			};
+			/* Add this address as an alias */
+			rpc_clnt_add_xprt(clp->cl_rpcclient, &xprt_args,
+					rpc_clnt_test_and_add_xprt, NULL);
+		} else
+			clp = get_v3_ds_connect(mds_srv,
+					(struct sockaddr *)&da->da_addr,
+					da->da_addrlen, IPPROTO_TCP,
+					timeo, retrans);
+	}
+
+	if (IS_ERR(clp)) {
+		status = PTR_ERR(clp);
+		goto out;
+	}
+
+	smp_wmb();
+	WRITE_ONCE(ds->ds_clp, clp);
+	dprintk("%s [new] addr: %s\n", __func__, ds->ds_remotestr);
+out:
+	return status;
+}
+
+static int _nfs4_pnfs_v4_ds_connect(struct nfs_server *mds_srv,
+				 struct nfs4_pnfs_ds *ds,
+				 unsigned int timeo,
+				 unsigned int retrans,
+				 u32 minor_version)
+{
+	struct nfs_client *clp = ERR_PTR(-EIO);
+	struct nfs4_pnfs_ds_addr *da;
+	int status = 0;
+
+	dprintk("--> %s DS %s\n", __func__, ds->ds_remotestr);
+
+	list_for_each_entry(da, &ds->ds_addrs, da_node) {
+		dprintk("%s: DS %s: trying address %s\n",
+			__func__, ds->ds_remotestr, da->da_remotestr);
+
+		if (!IS_ERR(clp) && clp->cl_mvops->session_trunk) {
+			struct xprt_create xprt_args = {
+				.ident = XPRT_TRANSPORT_TCP,
+				.net = clp->cl_net,
+				.dstaddr = (struct sockaddr *)&da->da_addr,
+				.addrlen = da->da_addrlen,
+				.servername = clp->cl_hostname,
+			};
+			struct nfs4_add_xprt_data xprtdata = {
+				.clp = clp,
+				.cred = nfs4_get_clid_cred(clp),
+			};
+			struct rpc_add_xprt_test rpcdata = {
+				.add_xprt_test = clp->cl_mvops->session_trunk,
+				.data = &xprtdata,
+			};
+
+			/**
+			* Test this address for session trunking and
+			* add as an alias
+			*/
+			rpc_clnt_add_xprt(clp->cl_rpcclient, &xprt_args,
+					  rpc_clnt_setup_test_and_add_xprt,
+					  &rpcdata);
+			if (xprtdata.cred)
+				put_rpccred(xprtdata.cred);
+		} else {
+			clp = nfs4_set_ds_client(mds_srv,
+						(struct sockaddr *)&da->da_addr,
+						da->da_addrlen, IPPROTO_TCP,
+						timeo, retrans, minor_version);
+			if (IS_ERR(clp))
+				continue;
+
+			status = nfs4_init_ds_session(clp,
+					mds_srv->nfs_client->cl_lease_time);
+			if (status) {
+				nfs_put_client(clp);
+				clp = ERR_PTR(-EIO);
+				continue;
+			}
+
+		}
+	}
+
+	if (IS_ERR(clp)) {
+		status = PTR_ERR(clp);
+		goto out;
+	}
+
+	smp_wmb();
+	WRITE_ONCE(ds->ds_clp, clp);
+	dprintk("%s [new] addr: %s\n", __func__, ds->ds_remotestr);
+out:
+	return status;
+}
+
+/*
+ * Create an rpc connection to the nfs4_pnfs_ds data server.
+ * Currently only supports IPv4 and IPv6 addresses.
+ * If connection fails, make devid unavailable and return a -errno.
+ */
+int nfs4_pnfs_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds,
+			  struct nfs4_deviceid_node *devid, unsigned int timeo,
+			  unsigned int retrans, u32 version, u32 minor_version)
+{
+	int err;
+
+	do {
+		err = nfs4_wait_ds_connect(ds);
+		if (err || ds->ds_clp)
+			goto out;
+		if (nfs4_test_deviceid_unavailable(devid))
+			return -ENODEV;
+	} while (test_and_set_bit(NFS4DS_CONNECTING, &ds->ds_state) != 0);
+
+	if (ds->ds_clp)
+		goto connect_done;
+
+	switch (version) {
+	case 3:
+		err = _nfs4_pnfs_v3_ds_connect(mds_srv, ds, timeo, retrans);
+		break;
+	case 4:
+		err = _nfs4_pnfs_v4_ds_connect(mds_srv, ds, timeo, retrans,
+					       minor_version);
+		break;
+	default:
+		dprintk("%s: unsupported DS version %d\n", __func__, version);
+		err = -EPROTONOSUPPORT;
+	}
+
+connect_done:
+	nfs4_clear_ds_conn_bit(ds);
+out:
+	/*
+	 * At this point the ds->ds_clp should be ready, but it might have
+	 * hit an error.
+	 */
+	if (!err) {
+		if (!ds->ds_clp || !nfs_client_init_is_complete(ds->ds_clp)) {
+			WARN_ON_ONCE(ds->ds_clp ||
+				!nfs4_test_deviceid_unavailable(devid));
+			return -EINVAL;
+		}
+		err = nfs_client_init_status(ds->ds_clp);
+	}
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(nfs4_pnfs_ds_connect);
+
+/*
+ * Currently only supports ipv4, ipv6 and one multi-path address.
+ */
+struct nfs4_pnfs_ds_addr *
+nfs4_decode_mp_ds_addr(struct net *net, struct xdr_stream *xdr, gfp_t gfp_flags)
+{
+	struct nfs4_pnfs_ds_addr *da = NULL;
+	char *buf, *portstr;
+	__be16 port;
+	int nlen, rlen;
+	int tmp[2];
+	__be32 *p;
+	char *netid, *match_netid;
+	size_t len, match_netid_len;
+	char *startsep = "";
+	char *endsep = "";
+
+
+	/* r_netid */
+	p = xdr_inline_decode(xdr, 4);
+	if (unlikely(!p))
+		goto out_err;
+	nlen = be32_to_cpup(p++);
+
+	p = xdr_inline_decode(xdr, nlen);
+	if (unlikely(!p))
+		goto out_err;
+
+	netid = kmalloc(nlen+1, gfp_flags);
+	if (unlikely(!netid))
+		goto out_err;
+
+	netid[nlen] = '\0';
+	memcpy(netid, p, nlen);
+
+	/* r_addr: ip/ip6addr with port in dec octets - see RFC 5665 */
+	p = xdr_inline_decode(xdr, 4);
+	if (unlikely(!p))
+		goto out_free_netid;
+	rlen = be32_to_cpup(p);
+
+	p = xdr_inline_decode(xdr, rlen);
+	if (unlikely(!p))
+		goto out_free_netid;
+
+	/* port is ".ABC.DEF", 8 chars max */
+	if (rlen > INET6_ADDRSTRLEN + IPV6_SCOPE_ID_LEN + 8) {
+		dprintk("%s: Invalid address, length %d\n", __func__,
+			rlen);
+		goto out_free_netid;
+	}
+	buf = kmalloc(rlen + 1, gfp_flags);
+	if (!buf) {
+		dprintk("%s: Not enough memory\n", __func__);
+		goto out_free_netid;
+	}
+	buf[rlen] = '\0';
+	memcpy(buf, p, rlen);
+
+	/* replace port '.' with '-' */
+	portstr = strrchr(buf, '.');
+	if (!portstr) {
+		dprintk("%s: Failed finding expected dot in port\n",
+			__func__);
+		goto out_free_buf;
+	}
+	*portstr = '-';
+
+	/* find '.' between address and port */
+	portstr = strrchr(buf, '.');
+	if (!portstr) {
+		dprintk("%s: Failed finding expected dot between address and "
+			"port\n", __func__);
+		goto out_free_buf;
+	}
+	*portstr = '\0';
+
+	da = kzalloc(sizeof(*da), gfp_flags);
+	if (unlikely(!da))
+		goto out_free_buf;
+
+	INIT_LIST_HEAD(&da->da_node);
+
+	if (!rpc_pton(net, buf, portstr-buf, (struct sockaddr *)&da->da_addr,
+		      sizeof(da->da_addr))) {
+		dprintk("%s: error parsing address %s\n", __func__, buf);
+		goto out_free_da;
+	}
+
+	portstr++;
+	sscanf(portstr, "%d-%d", &tmp[0], &tmp[1]);
+	port = htons((tmp[0] << 8) | (tmp[1]));
+
+	switch (da->da_addr.ss_family) {
+	case AF_INET:
+		((struct sockaddr_in *)&da->da_addr)->sin_port = port;
+		da->da_addrlen = sizeof(struct sockaddr_in);
+		match_netid = "tcp";
+		match_netid_len = 3;
+		break;
+
+	case AF_INET6:
+		((struct sockaddr_in6 *)&da->da_addr)->sin6_port = port;
+		da->da_addrlen = sizeof(struct sockaddr_in6);
+		match_netid = "tcp6";
+		match_netid_len = 4;
+		startsep = "[";
+		endsep = "]";
+		break;
+
+	default:
+		dprintk("%s: unsupported address family: %u\n",
+			__func__, da->da_addr.ss_family);
+		goto out_free_da;
+	}
+
+	if (nlen != match_netid_len || strncmp(netid, match_netid, nlen)) {
+		dprintk("%s: ERROR: r_netid \"%s\" != \"%s\"\n",
+			__func__, netid, match_netid);
+		goto out_free_da;
+	}
+
+	/* save human readable address */
+	len = strlen(startsep) + strlen(buf) + strlen(endsep) + 7;
+	da->da_remotestr = kzalloc(len, gfp_flags);
+
+	/* NULL is ok, only used for dprintk */
+	if (da->da_remotestr)
+		snprintf(da->da_remotestr, len, "%s%s%s:%u", startsep,
+			 buf, endsep, ntohs(port));
+
+	dprintk("%s: Parsed DS addr %s\n", __func__, da->da_remotestr);
+	kfree(buf);
+	kfree(netid);
+	return da;
+
+out_free_da:
+	kfree(da);
+out_free_buf:
+	dprintk("%s: Error parsing DS addr: %s\n", __func__, buf);
+	kfree(buf);
+out_free_netid:
+	kfree(netid);
+out_err:
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(nfs4_decode_mp_ds_addr);
+
+void
+pnfs_layout_mark_request_commit(struct nfs_page *req,
+				struct pnfs_layout_segment *lseg,
+				struct nfs_commit_info *cinfo,
+				u32 ds_commit_idx)
+{
+	struct list_head *list;
+	struct pnfs_commit_bucket *buckets;
+
+	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
+	buckets = cinfo->ds->buckets;
+	list = &buckets[ds_commit_idx].written;
+	if (list_empty(list)) {
+		if (!pnfs_is_valid_lseg(lseg)) {
+			mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
+			cinfo->completion_ops->resched_write(cinfo, req);
+			return;
+		}
+		/* Non-empty buckets hold a reference on the lseg.  That ref
+		 * is normally transferred to the COMMIT call and released
+		 * there.  It could also be released if the last req is pulled
+		 * off due to a rewrite, in which case it will be done in
+		 * pnfs_common_clear_request_commit
+		 */
+		WARN_ON_ONCE(buckets[ds_commit_idx].wlseg != NULL);
+		buckets[ds_commit_idx].wlseg = pnfs_get_lseg(lseg);
+	}
+	set_bit(PG_COMMIT_TO_DS, &req->wb_flags);
+	cinfo->ds->nwritten++;
+
+	nfs_request_add_commit_list_locked(req, list, cinfo);
+	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
+	nfs_mark_page_unstable(req->wb_page, cinfo);
+}
+EXPORT_SYMBOL_GPL(pnfs_layout_mark_request_commit);
+
+int
+pnfs_nfs_generic_sync(struct inode *inode, bool datasync)
+{
+	int ret;
+
+	if (!pnfs_layoutcommit_outstanding(inode))
+		return 0;
+	ret = nfs_commit_inode(inode, FLUSH_SYNC);
+	if (ret < 0)
+		return ret;
+	if (datasync)
+		return 0;
+	return pnfs_layoutcommit_inode(inode, true);
+}
+EXPORT_SYMBOL_GPL(pnfs_nfs_generic_sync);
+