NFS client bugfixes and cleanups for 3.10

- NLM: stable fix for NFSv2/v3 blocking locks - NFSv4.x: stable fixes for the delegation recall error handling code - NFSv4.x: Security flavour negotiation fixes and cleanups by Chuck Lever - SUNRPC: A number of RPCSEC_GSS fixes and cleanups also from Chuck - NFSv4.x assorted state management and reboot recovery bugfixes - NFSv4.1: In cases where we have already looked up a file, and hold a valid filehandle, use the new open-by-filehandle operation instead of opening by name. - Allow the NFSv4.1 callback thread to freeze - NFSv4.x: ensure that file unlock waits for readahead to complete - NFSv4.1: ensure that the RPC layer doesn't override the NFS session table size negotiation by limiting the number of slots. - NFSv4.x: Fix SETATTR spec compatibility issues -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) iQIcBAABAgAGBQJRfu+cAAoJEGcL54qWCgDylxkP/24cXOLHMKMYnIab0cQYIW2m SQgADGE+MqgTVlWjGVWublVMDY1R51iINsksAjxMtXYt50FdBJEqV2uxIGi4VnbR nR9eppqQ6vk5e6r5+aZyVmWKoLFnJ4MBF6OpPUZB5mf8iH/fiixmSYLvseopPdDj bjHwCxg+xEgew5EhQF/xqkEfkAp2NN84xUksTWb9uDIW2c3SJweY/ZVR2Zsqpugm oqYVtrSLvNKqINQG8OP10s+mRWULwoqapF+kEHlxNbRy26C0zlbXPaneSgYzqHsY OyRkAT7uJJqStYlqdW7k+DhyNMB+T33WAGJpWQlfJGYk5d/n0rtBJDVo0hfhCSQr VkOXiO9J08NMbelCu4+0CJii7h5GCaqpuJEEmNL6AlF/TJVkIQJuRaG2+WDmEtO2 oYd4UfXlAbUuts1SW7u/yyN/yrjVTm1tZYRBqn2VJdqh1s8dMxEWPct2Yn314mpS ODAnbDkEhtWlc9cloSRnwKec5WcxMZb19IJeK9ZvHm7PfIu/QHtj6Ren8s1//bZI OMQxC/Vf/wcjMdNtr7QdMNxWG1aK8DL9mYP5XwCrkZ560LIrtxmhyqYeoGAfgO5u +K/gKmQwjsaPhEa8jbP2/wI0II9yKPWj/fVwqhbhqaBUx5GA2iAKcdpPP6JAMAti +PXkLTtkyrIgSNwzl63S =Hgot -----END PGP SIGNATURE----- Merge tag 'nfs-for-3.10-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs Pull NFS client bugfixes and cleanups from Trond Myklebust: - NLM: stable fix for NFSv2/v3 blocking locks - NFSv4.x: stable fixes for the delegation recall error handling code - NFSv4.x: Security flavour negotiation fixes and cleanups by Chuck Lever - SUNRPC: A number of RPCSEC_GSS fixes and cleanups also from Chuck - NFSv4.x assorted state management and reboot recovery bugfixes - NFSv4.1: In cases where we have already looked up a file, and hold a valid filehandle, use the new open-by-filehandle operation instead of opening by name. - Allow the NFSv4.1 callback thread to freeze - NFSv4.x: ensure that file unlock waits for readahead to complete - NFSv4.1: ensure that the RPC layer doesn't override the NFS session table size negotiation by limiting the number of slots. - NFSv4.x: Fix SETATTR spec compatibility issues * tag 'nfs-for-3.10-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (67 commits) NFSv4: Warn once about servers that incorrectly apply open mode to setattr NFSv4: Servers should only check SETATTR stateid open mode on size change NFSv4: Don't recheck permissions on open in case of recovery cached open NFSv4.1: Don't do a delegated open for NFS4_OPEN_CLAIM_DELEG_CUR_FH modes NFSv4.1: Use the more efficient open_noattr call for open-by-filehandle NFS: Retry SETCLIENTID with AUTH_SYS instead of AUTH_NONE NFSv4: Ensure that we clear the NFS_OPEN_STATE flag when appropriate LOCKD: Ensure that nlmclnt_block resets block->b_status after a server reboot NFSv4: Ensure the LOCK call cannot use the delegation stateid NFSv4: Use the open stateid if the delegation has the wrong mode nfs: Send atime and mtime as a 64bit value NFSv4: Record the OPEN create mode used in the nfs4_opendata structure NFSv4.1: Set the RPC_CLNT_CREATE_INFINITE_SLOTS flag for NFSv4.1 transports SUNRPC: Allow rpc_create() to request that TCP slots be unlimited SUNRPC: Fix a livelock problem in the xprt->backlog queue NFSv4: Fix handling of revoked delegations by setattr NFSv4 release the sequence id in the return on close case nfs: remove unnecessary check for NULL inode->i_flock from nfs_delegation_claim_locks NFS: Ensure that NFS file unlock waits for readahead to complete NFS: Add functionality to allow waiting on all outstanding reads to complete ...
2026-10-30 11:41:38 -04:00 · 2013-04-30 11:28:08 -07:00 · 2013-04-30 11:28:08 -07:00 · 8728f986fe
commit 8728f986fe
parent e72859b87f 721ccfb79b
41 changed files with 1174 additions and 563 deletions
--- a/net/sunrpc/Kconfig
+++ b/net/sunrpc/Kconfig
@ -3,6 +3,7 @@ config SUNRPC

 config SUNRPC_GSS
 	tristate
+	select OID_REGISTRY

 config SUNRPC_BACKCHANNEL
 	bool
@ -24,7 +25,6 @@ config SUNRPC_XPRT_RDMA
 config SUNRPC_SWAP
 	bool
 	depends on SUNRPC
-	select NETVM

 config RPCSEC_GSS_KRB5
 	tristate "Secure RPC: Kerberos V mechanism"
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@ -82,7 +82,7 @@ MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");

 static u32
 pseudoflavor_to_flavor(u32 flavor) {
-	if (flavor >= RPC_AUTH_MAXFLAVOR)
+	if (flavor > RPC_AUTH_MAXFLAVOR)
 		return RPC_AUTH_GSS;
 	return flavor;
 }
@ -123,6 +123,79 @@ rpcauth_unregister(const struct rpc_authops *ops)
 }
 EXPORT_SYMBOL_GPL(rpcauth_unregister);

+/**
+ * rpcauth_get_pseudoflavor - check if security flavor is supported
+ * @flavor: a security flavor
+ * @info: a GSS mech OID, quality of protection, and service value
+ *
+ * Verifies that an appropriate kernel module is available or already loaded.
+ * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is
+ * not supported locally.
+ */
+rpc_authflavor_t
+rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)
+{
+	const struct rpc_authops *ops;
+	rpc_authflavor_t pseudoflavor;
+
+	ops = auth_flavors[flavor];
+	if (ops == NULL)
+		request_module("rpc-auth-%u", flavor);
+	spin_lock(&rpc_authflavor_lock);
+	ops = auth_flavors[flavor];
+	if (ops == NULL || !try_module_get(ops->owner)) {
+		spin_unlock(&rpc_authflavor_lock);
+		return RPC_AUTH_MAXFLAVOR;
+	}
+	spin_unlock(&rpc_authflavor_lock);
+
+	pseudoflavor = flavor;
+	if (ops->info2flavor != NULL)
+		pseudoflavor = ops->info2flavor(info);
+
+	module_put(ops->owner);
+	return pseudoflavor;
+}
+EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);
+
+/**
+ * rpcauth_get_gssinfo - find GSS tuple matching a GSS pseudoflavor
+ * @pseudoflavor: GSS pseudoflavor to match
+ * @info: rpcsec_gss_info structure to fill in
+ *
+ * Returns zero and fills in "info" if pseudoflavor matches a
+ * supported mechanism.
+ */
+int
+rpcauth_get_gssinfo(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
+{
+	rpc_authflavor_t flavor = pseudoflavor_to_flavor(pseudoflavor);
+	const struct rpc_authops *ops;
+	int result;
+
+	if (flavor >= RPC_AUTH_MAXFLAVOR)
+		return -EINVAL;
+
+	ops = auth_flavors[flavor];
+	if (ops == NULL)
+		request_module("rpc-auth-%u", flavor);
+	spin_lock(&rpc_authflavor_lock);
+	ops = auth_flavors[flavor];
+	if (ops == NULL || !try_module_get(ops->owner)) {
+		spin_unlock(&rpc_authflavor_lock);
+		return -ENOENT;
+	}
+	spin_unlock(&rpc_authflavor_lock);
+
+	result = -ENOENT;
+	if (ops->flavor2info != NULL)
+		result = ops->flavor2info(pseudoflavor, info);
+
+	module_put(ops->owner);
+	return result;
+}
+EXPORT_SYMBOL_GPL(rpcauth_get_gssinfo);
+
 /**
 * rpcauth_list_flavors - discover registered flavors and pseudoflavors
 * @array: array to fill in
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@ -1641,6 +1641,8 @@ static const struct rpc_authops authgss_ops = {
 	.pipes_create	= gss_pipes_dentries_create,
 	.pipes_destroy	= gss_pipes_dentries_destroy,
 	.list_pseudoflavors = gss_mech_list_pseudoflavors,
+	.info2flavor	= gss_mech_info2flavor,
+	.flavor2info	= gss_mech_flavor2info,
 };

 static const struct rpc_credops gss_credops = {
@ -1733,6 +1735,7 @@ static void __exit exit_rpcsec_gss(void)
 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
 }

+MODULE_ALIAS("rpc-auth-6");
 MODULE_LICENSE("GPL");
 module_param_named(expired_cred_retry_delay,
 		   gss_expired_cred_retry_delay,
--- a/net/sunrpc/auth_gss/gss_krb5_mech.c
+++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
@ -729,16 +729,19 @@ static const struct gss_api_ops gss_kerberos_ops = {
 static struct pf_desc gss_kerberos_pfs[] = {
 	[0] = {
 		.pseudoflavor = RPC_AUTH_GSS_KRB5,
+		.qop = GSS_C_QOP_DEFAULT,
 		.service = RPC_GSS_SVC_NONE,
 		.name = "krb5",
 	},
 	[1] = {
 		.pseudoflavor = RPC_AUTH_GSS_KRB5I,
+		.qop = GSS_C_QOP_DEFAULT,
 		.service = RPC_GSS_SVC_INTEGRITY,
 		.name = "krb5i",
 	},
 	[2] = {
 		.pseudoflavor = RPC_AUTH_GSS_KRB5P,
+		.qop = GSS_C_QOP_DEFAULT,
 		.service = RPC_GSS_SVC_PRIVACY,
 		.name = "krb5p",
 	},
@ -750,11 +753,12 @@ MODULE_ALIAS("rpc-auth-gss-krb5p");
 MODULE_ALIAS("rpc-auth-gss-390003");
 MODULE_ALIAS("rpc-auth-gss-390004");
 MODULE_ALIAS("rpc-auth-gss-390005");
+MODULE_ALIAS("rpc-auth-gss-1.2.840.113554.1.2.2");

 static struct gss_api_mech gss_kerberos_mech = {
 	.gm_name	= "krb5",
 	.gm_owner	= THIS_MODULE,
-	.gm_oid		= {9, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x02"},
+	.gm_oid		= { 9, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" },
 	.gm_ops		= &gss_kerberos_ops,
 	.gm_pf_num	= ARRAY_SIZE(gss_kerberos_pfs),
 	.gm_pfs		= gss_kerberos_pfs,
--- a/net/sunrpc/auth_gss/gss_mech_switch.c
+++ b/net/sunrpc/auth_gss/gss_mech_switch.c
@ -36,6 +36,7 @@
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/oid_registry.h>
 #include <linux/sunrpc/msg_prot.h>
 #include <linux/sunrpc/gss_asn1.h>
 #include <linux/sunrpc/auth_gss.h>
@ -102,8 +103,13 @@ out:
 	return status;
 }

-int
-gss_mech_register(struct gss_api_mech *gm)
+/**
+ * gss_mech_register - register a GSS mechanism
+ * @gm: GSS mechanism handle
+ *
+ * Returns zero if successful, or a negative errno.
+ */
+int gss_mech_register(struct gss_api_mech *gm)
 {
 	int status;

@ -116,11 +122,14 @@ gss_mech_register(struct gss_api_mech *gm)
 	dprintk("RPC:       registered gss mechanism %s\n", gm->gm_name);
 	return 0;
 }
-
 EXPORT_SYMBOL_GPL(gss_mech_register);

-void
-gss_mech_unregister(struct gss_api_mech *gm)
+/**
+ * gss_mech_unregister - release a GSS mechanism
+ * @gm: GSS mechanism handle
+ *
+ */
+void gss_mech_unregister(struct gss_api_mech *gm)
 {
 	spin_lock(&registered_mechs_lock);
 	list_del(&gm->gm_list);
@ -128,18 +137,14 @@ gss_mech_unregister(struct gss_api_mech *gm)
 	dprintk("RPC:       unregistered gss mechanism %s\n", gm->gm_name);
 	gss_mech_free(gm);
 }
-
 EXPORT_SYMBOL_GPL(gss_mech_unregister);

-struct gss_api_mech *
-gss_mech_get(struct gss_api_mech *gm)
+static struct gss_api_mech *gss_mech_get(struct gss_api_mech *gm)
 {
 	__module_get(gm->gm_owner);
 	return gm;
 }

-EXPORT_SYMBOL_GPL(gss_mech_get);
-
 static struct gss_api_mech *
 _gss_mech_get_by_name(const char *name)
 {
@ -169,12 +174,16 @@ struct gss_api_mech * gss_mech_get_by_name(const char *name)
 	}
 	return gm;
 }
-EXPORT_SYMBOL_GPL(gss_mech_get_by_name);

-struct gss_api_mech *
-gss_mech_get_by_OID(struct xdr_netobj *obj)
+static struct gss_api_mech *gss_mech_get_by_OID(struct rpcsec_gss_oid *obj)
 {
 	struct gss_api_mech	*pos, *gm = NULL;
+	char buf[32];
+
+	if (sprint_oid(obj->data, obj->len, buf, sizeof(buf)) < 0)
+		return NULL;
+	dprintk("RPC:       %s(%s)\n", __func__, buf);
+	request_module("rpc-auth-gss-%s", buf);

 	spin_lock(&registered_mechs_lock);
 	list_for_each_entry(pos, &registered_mechs, gm_list) {
@ -188,11 +197,8 @@ gss_mech_get_by_OID(struct xdr_netobj *obj)
 	}
 	spin_unlock(&registered_mechs_lock);
 	return gm;
-
 }

-EXPORT_SYMBOL_GPL(gss_mech_get_by_OID);
-
 static inline int
 mech_supports_pseudoflavor(struct gss_api_mech *gm, u32 pseudoflavor)
 {
@ -237,8 +243,6 @@ gss_mech_get_by_pseudoflavor(u32 pseudoflavor)
 	return gm;
 }

-EXPORT_SYMBOL_GPL(gss_mech_get_by_pseudoflavor);
-
 /**
 * gss_mech_list_pseudoflavors - Discover registered GSS pseudoflavors
 * @array: array to fill in
@ -268,19 +272,82 @@ int gss_mech_list_pseudoflavors(rpc_authflavor_t *array_ptr, int size)
 	return i;
 }

-u32
-gss_svc_to_pseudoflavor(struct gss_api_mech *gm, u32 service)
+/**
+ * gss_svc_to_pseudoflavor - map a GSS service number to a pseudoflavor
+ * @gm: GSS mechanism handle
+ * @qop: GSS quality-of-protection value
+ * @service: GSS service value
+ *
+ * Returns a matching security flavor, or RPC_AUTH_MAXFLAVOR if none is found.
+ */
+rpc_authflavor_t gss_svc_to_pseudoflavor(struct gss_api_mech *gm, u32 qop,
+					 u32 service)
 {
 	int i;

 	for (i = 0; i < gm->gm_pf_num; i++) {
-		if (gm->gm_pfs[i].service == service) {
+		if (gm->gm_pfs[i].qop == qop &&
+		    gm->gm_pfs[i].service == service) {
 			return gm->gm_pfs[i].pseudoflavor;
 		}
 	}
-	return RPC_AUTH_MAXFLAVOR; /* illegal value */
+	return RPC_AUTH_MAXFLAVOR;
+}
+
+/**
+ * gss_mech_info2flavor - look up a pseudoflavor given a GSS tuple
+ * @info: a GSS mech OID, quality of protection, and service value
+ *
+ * Returns a matching pseudoflavor, or RPC_AUTH_MAXFLAVOR if the tuple is
+ * not supported.
+ */
+rpc_authflavor_t gss_mech_info2flavor(struct rpcsec_gss_info *info)
+{
+	rpc_authflavor_t pseudoflavor;
+	struct gss_api_mech *gm;
+
+	gm = gss_mech_get_by_OID(&info->oid);
+	if (gm == NULL)
+		return RPC_AUTH_MAXFLAVOR;
+
+	pseudoflavor = gss_svc_to_pseudoflavor(gm, info->qop, info->service);
+
+	gss_mech_put(gm);
+	return pseudoflavor;
+}
+
+/**
+ * gss_mech_flavor2info - look up a GSS tuple for a given pseudoflavor
+ * @pseudoflavor: GSS pseudoflavor to match
+ * @info: rpcsec_gss_info structure to fill in
+ *
+ * Returns zero and fills in "info" if pseudoflavor matches a
+ * supported mechanism.  Otherwise a negative errno is returned.
+ */
+int gss_mech_flavor2info(rpc_authflavor_t pseudoflavor,
+			 struct rpcsec_gss_info *info)
+{
+	struct gss_api_mech *gm;
+	int i;
+
+	gm = gss_mech_get_by_pseudoflavor(pseudoflavor);
+	if (gm == NULL)
+		return -ENOENT;
+
+	for (i = 0; i < gm->gm_pf_num; i++) {
+		if (gm->gm_pfs[i].pseudoflavor == pseudoflavor) {
+			memcpy(info->oid.data, gm->gm_oid.data, gm->gm_oid.len);
+			info->oid.len = gm->gm_oid.len;
+			info->qop = gm->gm_pfs[i].qop;
+			info->service = gm->gm_pfs[i].service;
+			gss_mech_put(gm);
+			return 0;
+		}
+	}
+
+	gss_mech_put(gm);
+	return -ENOENT;
 }
-EXPORT_SYMBOL_GPL(gss_svc_to_pseudoflavor);

 u32
 gss_pseudoflavor_to_service(struct gss_api_mech *gm, u32 pseudoflavor)
@ -294,8 +361,6 @@ gss_pseudoflavor_to_service(struct gss_api_mech *gm, u32 pseudoflavor)
 	return 0;
 }

-EXPORT_SYMBOL_GPL(gss_pseudoflavor_to_service);
-
 char *
 gss_service_to_auth_domain_name(struct gss_api_mech *gm, u32 service)
 {
@ -308,8 +373,6 @@ gss_service_to_auth_domain_name(struct gss_api_mech *gm, u32 service)
 	return NULL;
 }

-EXPORT_SYMBOL_GPL(gss_service_to_auth_domain_name);
-
 void
 gss_mech_put(struct gss_api_mech * gm)
 {
@ -317,8 +380,6 @@ gss_mech_put(struct gss_api_mech * gm)
 		module_put(gm->gm_owner);
 }

-EXPORT_SYMBOL_GPL(gss_mech_put);
-
 /* The mech could probably be determined from the token instead, but it's just
 * as easy for now to pass it in. */
 int
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@ -1220,7 +1220,9 @@ svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp)
 		svcdata->rsci = rsci;
 		cache_get(&rsci->h);
 		rqstp->rq_cred.cr_flavor = gss_svc_to_pseudoflavor(
-					rsci->mechctx->mech_type, gc->gc_svc);
+					rsci->mechctx->mech_type,
+					GSS_C_QOP_DEFAULT,
+					gc->gc_svc);
 		ret = SVC_OK;
 		goto out;
 	}
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@ -411,6 +411,8 @@ struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 	};
 	char servername[48];

+	if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
+		xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
 	/*
 	 * If the caller chooses not to specify a hostname, whip
 	 * up a string representation of the passed-in address.
@ -1301,6 +1303,8 @@ call_reserve(struct rpc_task *task)
 	xprt_reserve(task);
 }

+static void call_retry_reserve(struct rpc_task *task);
+
 /*
 * 1b.	Grok the result of xprt_reserve()
 */
@ -1342,7 +1346,7 @@ call_reserveresult(struct rpc_task *task)
 	case -ENOMEM:
 		rpc_delay(task, HZ >> 2);
 	case -EAGAIN:	/* woken up; retry */
-		task->tk_action = call_reserve;
+		task->tk_action = call_retry_reserve;
 		return;
 	case -EIO:	/* probably a shutdown */
 		break;
@ -1354,6 +1358,19 @@ call_reserveresult(struct rpc_task *task)
 	rpc_exit(task, status);
 }

+/*
+ * 1c.	Retry reserving an RPC call slot
+ */
+static void
+call_retry_reserve(struct rpc_task *task)
+{
+	dprint_status(task);
+
+	task->tk_status  = 0;
+	task->tk_action  = call_reserveresult;
+	xprt_retry_reserve(task);
+}
+
 /*
 * 2.	Bind and/or refresh the credentials
 */
@ -1639,22 +1656,26 @@ call_connect_status(struct rpc_task *task)

 	dprint_status(task);

-	task->tk_status = 0;
-	if (status >= 0 || status == -EAGAIN) {
-		clnt->cl_stats->netreconn++;
-		task->tk_action = call_transmit;
-		return;
-	}
-
 	trace_rpc_connect_status(task, status);
 	switch (status) {
 		/* if soft mounted, test if we've timed out */
 	case -ETIMEDOUT:
 		task->tk_action = call_timeout;
-		break;
-	default:
-		rpc_exit(task, -EIO);
+		return;
+	case -ECONNREFUSED:
+	case -ECONNRESET:
+	case -ENETUNREACH:
+		if (RPC_IS_SOFTCONN(task))
+			break;
+		/* retry with existing socket, after a delay */
+	case 0:
+	case -EAGAIN:
+		task->tk_status = 0;
+		clnt->cl_stats->netreconn++;
+		task->tk_action = call_transmit;
+		return;
 	}
+	rpc_exit(task, status);
 }

 /*
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@ -948,6 +948,34 @@ void xprt_transmit(struct rpc_task *task)
 	spin_unlock_bh(&xprt->transport_lock);
 }

+static void xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+	set_bit(XPRT_CONGESTED, &xprt->state);
+	rpc_sleep_on(&xprt->backlog, task, NULL);
+}
+
+static void xprt_wake_up_backlog(struct rpc_xprt *xprt)
+{
+	if (rpc_wake_up_next(&xprt->backlog) == NULL)
+		clear_bit(XPRT_CONGESTED, &xprt->state);
+}
+
+static bool xprt_throttle_congested(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+	bool ret = false;
+
+	if (!test_bit(XPRT_CONGESTED, &xprt->state))
+		goto out;
+	spin_lock(&xprt->reserve_lock);
+	if (test_bit(XPRT_CONGESTED, &xprt->state)) {
+		rpc_sleep_on(&xprt->backlog, task, NULL);
+		ret = true;
+	}
+	spin_unlock(&xprt->reserve_lock);
+out:
+	return ret;
+}
+
 static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt, gfp_t gfp_flags)
 {
 	struct rpc_rqst *req = ERR_PTR(-EAGAIN);
@ -992,7 +1020,7 @@ void xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
 		task->tk_status = -ENOMEM;
 		break;
 	case -EAGAIN:
-		rpc_sleep_on(&xprt->backlog, task, NULL);
+		xprt_add_backlog(xprt, task);
 		dprintk("RPC:       waiting for request slot\n");
 	default:
 		task->tk_status = -EAGAIN;
@ -1028,7 +1056,7 @@ static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
 		memset(req, 0, sizeof(*req));	/* mark unused */
 		list_add(&req->rq_list, &xprt->free);
 	}
-	rpc_wake_up_next(&xprt->backlog);
+	xprt_wake_up_backlog(xprt);
 	spin_unlock(&xprt->reserve_lock);
 }

@ -1092,13 +1120,40 @@ EXPORT_SYMBOL_GPL(xprt_free);
 * xprt_reserve - allocate an RPC request slot
 * @task: RPC task requesting a slot allocation
 *
- * If no more slots are available, place the task on the transport's
+ * If the transport is marked as being congested, or if no more
+ * slots are available, place the task on the transport's
 * backlog queue.
 */
 void xprt_reserve(struct rpc_task *task)
 {
 	struct rpc_xprt	*xprt;

+	task->tk_status = 0;
+	if (task->tk_rqstp != NULL)
+		return;
+
+	task->tk_timeout = 0;
+	task->tk_status = -EAGAIN;
+	rcu_read_lock();
+	xprt = rcu_dereference(task->tk_client->cl_xprt);
+	if (!xprt_throttle_congested(xprt, task))
+		xprt->ops->alloc_slot(xprt, task);
+	rcu_read_unlock();
+}
+
+/**
+ * xprt_retry_reserve - allocate an RPC request slot
+ * @task: RPC task requesting a slot allocation
+ *
+ * If no more slots are available, place the task on the transport's
+ * backlog queue.
+ * Note that the only difference with xprt_reserve is that we now
+ * ignore the value of the XPRT_CONGESTED flag.
+ */
+void xprt_retry_reserve(struct rpc_task *task)
+{
+	struct rpc_xprt	*xprt;
+
 	task->tk_status = 0;
 	if (task->tk_rqstp != NULL)
 		return;
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@ -2207,10 +2207,6 @@ static void xs_tcp_setup_socket(struct work_struct *work)
 		 */
 		xs_tcp_force_close(xprt);
 		break;
-	case -ECONNREFUSED:
-	case -ECONNRESET:
-	case -ENETUNREACH:
-		/* retry with existing socket, after a delay */
 	case 0:
 	case -EINPROGRESS:
 	case -EALREADY:
@ -2221,6 +2217,10 @@ static void xs_tcp_setup_socket(struct work_struct *work)
 		/* Happens, for instance, if the user specified a link
 		 * local IPv6 address without a scope-id.
 		 */
+	case -ECONNREFUSED:
+	case -ECONNRESET:
+	case -ENETUNREACH:
+		/* retry with existing socket, after a delay */
 		goto out;
 	}
 out_eagain:
@ -2767,9 +2767,13 @@ static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
 	struct rpc_xprt *xprt;
 	struct sock_xprt *transport;
 	struct rpc_xprt *ret;
+	unsigned int max_slot_table_size = xprt_max_tcp_slot_table_entries;
+
+	if (args->flags & XPRT_CREATE_INFINITE_SLOTS)
+		max_slot_table_size = RPC_MAX_SLOT_TABLE_LIMIT;

 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
-			xprt_max_tcp_slot_table_entries);
+			max_slot_table_size);
 	if (IS_ERR(xprt))
 		return xprt;
 	transport = container_of(xprt, struct sock_xprt, xprt);