NFS client bugfixes for Linux 5.11

Highlights include:
 
 Bugfixes:
 - SUNRPC: Handle 0 length opaque XDR object data properly
 - Fix a layout segment leak in pnfs_layout_process()
 - pNFS/NFSv4: Update the layout barrier when we schedule a layoutreturn
 - pNFS/NFSv4: Improve rejection of out-of-order layouts
 - pNFS/NFSv4: Try to return invalid layout in pnfs_layout_process()
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Merge tag 'nfs-for-5.11-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client fixes from Trond Myklebust:

 - SUNRPC: Handle 0 length opaque XDR object data properly

 - Fix a layout segment leak in pnfs_layout_process()

 - pNFS/NFSv4: Update the layout barrier when we schedule a layoutreturn

 - pNFS/NFSv4: Improve rejection of out-of-order layouts

 - pNFS/NFSv4: Try to return invalid layout in pnfs_layout_process()

* tag 'nfs-for-5.11-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  SUNRPC: Handle 0 length opaque XDR object data properly
  SUNRPC: Move simple_get_bytes and simple_get_netobj into private header
  pNFS/NFSv4: Improve rejection of out-of-order layouts
  pNFS/NFSv4: Update the layout barrier when we schedule a layoutreturn
  pNFS/NFSv4: Try to return invalid layout in pnfs_layout_process()
  pNFS/NFSv4: Fix a layout segment leak in pnfs_layout_process()

fs/nfs/pnfs.c

@@ -324,6 +324,21 @@ pnfs_grab_inode_layout_hdr(struct pnfs_layout_hdr *lo)
 	return NULL;
 }
 
+/*
+ * Compare 2 layout stateid sequence ids, to see which is newer,
+ * taking into account wraparound issues.
+ */
+static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
+{
+	return (s32)(s1 - s2) > 0;
+}
+
+static void pnfs_barrier_update(struct pnfs_layout_hdr *lo, u32 newseq)
+{
+	if (pnfs_seqid_is_newer(newseq, lo->plh_barrier))
+		lo->plh_barrier = newseq;
+}
+
 static void
 pnfs_set_plh_return_info(struct pnfs_layout_hdr *lo, enum pnfs_iomode iomode,
 			 u32 seq)
@@ -335,6 +350,7 @@ pnfs_set_plh_return_info(struct pnfs_layout_hdr *lo, enum pnfs_iomode iomode,
 	if (seq != 0) {
 		WARN_ON_ONCE(lo->plh_return_seq != 0 && lo->plh_return_seq != seq);
 		lo->plh_return_seq = seq;
+		pnfs_barrier_update(lo, seq);
 	}
 }
 
@@ -639,15 +655,6 @@ static int mark_lseg_invalid(struct pnfs_layout_segment *lseg,
 	return rv;
 }
 
-/*
- * Compare 2 layout stateid sequence ids, to see which is newer,
- * taking into account wraparound issues.
- */
-static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
-{
-	return (s32)(s1 - s2) > 0;
-}
-
 static bool
 pnfs_should_free_range(const struct pnfs_layout_range *lseg_range,
 		 const struct pnfs_layout_range *recall_range)
@@ -984,8 +991,7 @@ pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
 		new_barrier = be32_to_cpu(new->seqid);
 	else if (new_barrier == 0)
 		return;
-	if (pnfs_seqid_is_newer(new_barrier, lo->plh_barrier))
-		lo->plh_barrier = new_barrier;
+	pnfs_barrier_update(lo, new_barrier);
 }
 
 static bool
@@ -994,7 +1000,7 @@ pnfs_layout_stateid_blocked(const struct pnfs_layout_hdr *lo,
 {
 	u32 seqid = be32_to_cpu(stateid->seqid);
 
-	return !pnfs_seqid_is_newer(seqid, lo->plh_barrier);
+	return !pnfs_seqid_is_newer(seqid, lo->plh_barrier) && lo->plh_barrier;
 }
 
 /* lget is set to 1 if called from inside send_layoutget call chain */
@@ -1183,20 +1189,17 @@ pnfs_prepare_layoutreturn(struct pnfs_layout_hdr *lo,
 		return false;
 	set_bit(NFS_LAYOUT_RETURN, &lo->plh_flags);
 	pnfs_get_layout_hdr(lo);
-	if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags)) {
 	nfs4_stateid_copy(stateid, &lo->plh_stateid);
 	*cred = get_cred(lo->plh_lc_cred);
+	if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags)) {
 		if (lo->plh_return_seq != 0)
 			stateid->seqid = cpu_to_be32(lo->plh_return_seq);
 		if (iomode != NULL)
 			*iomode = lo->plh_return_iomode;
 		pnfs_clear_layoutreturn_info(lo);
-		return true;
-	}
-	nfs4_stateid_copy(stateid, &lo->plh_stateid);
-	*cred = get_cred(lo->plh_lc_cred);
-	if (iomode != NULL)
+	} else if (iomode != NULL)
 		*iomode = IOMODE_ANY;
+	pnfs_barrier_update(lo, be32_to_cpu(stateid->seqid));
 	return true;
 }
 
@@ -1909,6 +1912,11 @@ static void nfs_layoutget_end(struct pnfs_layout_hdr *lo)
 		wake_up_var(&lo->plh_outstanding);
 }
 
+static bool pnfs_is_first_layoutget(struct pnfs_layout_hdr *lo)
+{
+	return test_bit(NFS_LAYOUT_FIRST_LAYOUTGET, &lo->plh_flags);
+}
+
 static void pnfs_clear_first_layoutget(struct pnfs_layout_hdr *lo)
 {
 	unsigned long *bitlock = &lo->plh_flags;
@@ -2383,23 +2391,34 @@ pnfs_layout_process(struct nfs4_layoutget *lgp)
 		goto out_forget;
 	}
 
-	if (!pnfs_layout_is_valid(lo)) {
-		/* We have a completely new layout */
-		pnfs_set_layout_stateid(lo, &res->stateid, lgp->cred, true);
-	} else if (nfs4_stateid_match_other(&lo->plh_stateid, &res->stateid)) {
+	if (nfs4_stateid_match_other(&lo->plh_stateid, &res->stateid)) {
 		/* existing state ID, make sure the sequence number matches. */
 		if (pnfs_layout_stateid_blocked(lo, &res->stateid)) {
+			if (!pnfs_layout_is_valid(lo) &&
+			    pnfs_is_first_layoutget(lo))
+				lo->plh_barrier = 0;
 			dprintk("%s forget reply due to sequence\n", __func__);
 			goto out_forget;
 		}
 		pnfs_set_layout_stateid(lo, &res->stateid, lgp->cred, false);
-	} else {
+	} else if (pnfs_layout_is_valid(lo)) {
 		/*
 		 * We got an entirely new state ID.  Mark all segments for the
 		 * inode invalid, and retry the layoutget
 		 */
-		pnfs_mark_layout_stateid_invalid(lo, &free_me);
+		struct pnfs_layout_range range = {
+			.iomode = IOMODE_ANY,
+			.length = NFS4_MAX_UINT64,
+		};
+		pnfs_set_plh_return_info(lo, IOMODE_ANY, 0);
+		pnfs_mark_matching_lsegs_return(lo, &lo->plh_return_segs,
+						&range, 0);
 		goto out_forget;
+	} else {
+		/* We have a completely new layout */
+		if (!pnfs_is_first_layoutget(lo))
+			goto out_forget;
+		pnfs_set_layout_stateid(lo, &res->stateid, lgp->cred, true);
 	}
 
 	pnfs_get_lseg(lseg);

include/linux/sunrpc/xdr.h

@@ -25,8 +25,7 @@ struct rpc_rqst;
 #define XDR_QUADLEN(l)		(((l) + 3) >> 2)
 
 /*
- * Generic opaque `network object.' At the kernel level, this type
- * is used only by lockd.
+ * Generic opaque `network object.'
  */
 #define XDR_MAX_NETOBJ		1024
 struct xdr_netobj {

net/sunrpc/auth_gss/auth_gss.c

@@ -29,6 +29,7 @@
 #include <linux/uaccess.h>
 #include <linux/hashtable.h>
 
+#include "auth_gss_internal.h"
 #include "../netns.h"
 
 #include <trace/events/rpcgss.h>
@@ -125,35 +126,6 @@ gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx)
 	clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
 }
 
-static const void *
-simple_get_bytes(const void *p, const void *end, void *res, size_t len)
-{
-	const void *q = (const void *)((const char *)p + len);
-	if (unlikely(q > end || q < p))
-		return ERR_PTR(-EFAULT);
-	memcpy(res, p, len);
-	return q;
-}
-
-static inline const void *
-simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
-{
-	const void *q;
-	unsigned int len;
-
-	p = simple_get_bytes(p, end, &len, sizeof(len));
-	if (IS_ERR(p))
-		return p;
-	q = (const void *)((const char *)p + len);
-	if (unlikely(q > end || q < p))
-		return ERR_PTR(-EFAULT);
-	dest->data = kmemdup(p, len, GFP_NOFS);
-	if (unlikely(dest->data == NULL))
-		return ERR_PTR(-ENOMEM);
-	dest->len = len;
-	return q;
-}
-
 static struct gss_cl_ctx *
 gss_cred_get_ctx(struct rpc_cred *cred)
 {

net/sunrpc/auth_gss/auth_gss_internal.h

@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * linux/net/sunrpc/auth_gss/auth_gss_internal.h
+ *
+ * Internal definitions for RPCSEC_GSS client authentication
+ *
+ * Copyright (c) 2000 The Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ */
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/sunrpc/xdr.h>
+
+static inline const void *
+simple_get_bytes(const void *p, const void *end, void *res, size_t len)
+{
+	const void *q = (const void *)((const char *)p + len);
+	if (unlikely(q > end || q < p))
+		return ERR_PTR(-EFAULT);
+	memcpy(res, p, len);
+	return q;
+}
+
+static inline const void *
+simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
+{
+	const void *q;
+	unsigned int len;
+
+	p = simple_get_bytes(p, end, &len, sizeof(len));
+	if (IS_ERR(p))
+		return p;
+	q = (const void *)((const char *)p + len);
+	if (unlikely(q > end || q < p))
+		return ERR_PTR(-EFAULT);
+	if (len) {
+		dest->data = kmemdup(p, len, GFP_NOFS);
+		if (unlikely(dest->data == NULL))
+			return ERR_PTR(-ENOMEM);
+	} else
+		dest->data = NULL;
+	dest->len = len;
+	return q;
+}

net/sunrpc/auth_gss/gss_krb5_mech.c

@@ -21,6 +21,8 @@
 #include <linux/sunrpc/xdr.h>
 #include <linux/sunrpc/gss_krb5_enctypes.h>
 
+#include "auth_gss_internal.h"
+
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 # define RPCDBG_FACILITY	RPCDBG_AUTH
 #endif
@@ -143,35 +145,6 @@ get_gss_krb5_enctype(int etype)
 	return NULL;
 }
 
-static const void *
-simple_get_bytes(const void *p, const void *end, void *res, int len)
-{
-	const void *q = (const void *)((const char *)p + len);
-	if (unlikely(q > end || q < p))
-		return ERR_PTR(-EFAULT);
-	memcpy(res, p, len);
-	return q;
-}
-
-static const void *
-simple_get_netobj(const void *p, const void *end, struct xdr_netobj *res)
-{
-	const void *q;
-	unsigned int len;
-
-	p = simple_get_bytes(p, end, &len, sizeof(len));
-	if (IS_ERR(p))
-		return p;
-	q = (const void *)((const char *)p + len);
-	if (unlikely(q > end || q < p))
-		return ERR_PTR(-EFAULT);
-	res->data = kmemdup(p, len, GFP_NOFS);
-	if (unlikely(res->data == NULL))
-		return ERR_PTR(-ENOMEM);
-	res->len = len;
-	return q;
-}
-
 static inline const void *
 get_key(const void *p, const void *end,
 	struct krb5_ctx *ctx, struct crypto_sync_skcipher **res)