Merge tag 'nfsd-5.9' of git://git.linux-nfs.org/projects/cel/cel-2.6

Pull NFS server updates from Chuck Lever:
 "Highlights:
   - Support for user extended attributes on NFS (RFC 8276)
   - Further reduce unnecessary NFSv4 delegation recalls

  Notable fixes:
   - Fix recent krb5p regression
   - Address a few resource leaks and a rare NULL dereference

  Other:
   - De-duplicate RPC/RDMA error handling and other utility functions
   - Replace storage and display of kernel memory addresses by tracepoints"

* tag 'nfsd-5.9' of git://git.linux-nfs.org/projects/cel/cel-2.6: (38 commits)
  svcrdma: CM event handler clean up
  svcrdma: Remove transport reference counting
  svcrdma: Fix another Receive buffer leak
  SUNRPC: Refresh the show_rqstp_flags() macro
  nfsd: netns.h: delete a duplicated word
  SUNRPC: Fix ("SUNRPC: Add "@len" parameter to gss_unwrap()")
  nfsd: avoid a NULL dereference in __cld_pipe_upcall()
  nfsd4: a client's own opens needn't prevent delegations
  nfsd: Use seq_putc() in two functions
  svcrdma: Display chunk completion ID when posting a rw_ctxt
  svcrdma: Record send_ctxt completion ID in trace_svcrdma_post_send()
  svcrdma: Introduce Send completion IDs
  svcrdma: Record Receive completion ID in svc_rdma_decode_rqst
  svcrdma: Introduce Receive completion IDs
  svcrdma: Introduce infrastructure to support completion IDs
  svcrdma: Add common XDR encoders for RDMA and Read segments
  svcrdma: Add common XDR decoders for RDMA and Read segments
  SUNRPC: Add helpers for decoding list discriminators symbolically
  svcrdma: Remove declarations for functions long removed
  svcrdma: Clean up trace_svcrdma_send_failed() tracepoint
  ...

12 files changed, 1073 insertions, 69 deletions

diff --git a/fs/locks.c b/fs/locks.c
index 938fe325bc54..8fc0542f5132 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1808,6 +1808,9 @@ check_conflicting_open(struct file *filp, const long arg, int flags)
 
 	if (flags & FL_LAYOUT)
 		return 0;
+	if (flags & FL_DELEG)
+		/* We leave these checks to the caller. */
+		return 0;
 
 	if (arg == F_RDLCK)
 		return inode_is_open_for_write(inode) ? -EAGAIN : 0;
diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index 9217cb64bf0e..7346acda9d76 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -171,7 +171,7 @@ struct nfsd_net {
 	unsigned int             longest_chain_cachesize;
 
 	struct shrinker		nfsd_reply_cache_shrinker;
-	/* utsname taken from the the process that starts the server */
+	/* utsname taken from the process that starts the server */
 	char			nfsd_name[UNX_MAXNODENAME+1];
 };
 
diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index 9460be8a8321..f92161ce1f97 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -168,7 +168,7 @@ idtoname_show(struct seq_file *m, struct cache_detail *cd, struct cache_head *h)
 			ent->id);
 	if (test_bit(CACHE_VALID, &h->flags))
 		seq_printf(m, " %s", ent->name);
-	seq_printf(m, "\n");
+	seq_putc(m, '\n');
 	return 0;
 }
 
@@ -346,7 +346,7 @@ nametoid_show(struct seq_file *m, struct cache_detail *cd, struct cache_head *h)
 			ent->name);
 	if (test_bit(CACHE_VALID, &h->flags))
 		seq_printf(m, " %u", ent->id);
-	seq_printf(m, "\n");
+	seq_putc(m, '\n');
 	return 0;
 }
 
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index a09c35f0f6f0..a527da3d8052 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -566,8 +566,14 @@ nfsd4_access(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	     union nfsd4_op_u *u)
 {
 	struct nfsd4_access *access = &u->access;
+	u32 access_full;
 
-	if (access->ac_req_access & ~NFS3_ACCESS_FULL)
+	access_full = NFS3_ACCESS_FULL;
+	if (cstate->minorversion >= 2)
+		access_full |= NFS4_ACCESS_XALIST | NFS4_ACCESS_XAREAD |
+			       NFS4_ACCESS_XAWRITE;
+
+	if (access->ac_req_access & ~access_full)
 		return nfserr_inval;
 
 	access->ac_resp_access = access->ac_req_access;
@@ -2091,6 +2097,68 @@ out:
 }
 #endif /* CONFIG_NFSD_PNFS */
 
+static __be32
+nfsd4_getxattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	       union nfsd4_op_u *u)
+{
+	struct nfsd4_getxattr *getxattr = &u->getxattr;
+
+	return nfsd_getxattr(rqstp, &cstate->current_fh,
+			     getxattr->getxa_name, &getxattr->getxa_buf,
+			     &getxattr->getxa_len);
+}
+
+static __be32
+nfsd4_setxattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	   union nfsd4_op_u *u)
+{
+	struct nfsd4_setxattr *setxattr = &u->setxattr;
+	__be32 ret;
+
+	if (opens_in_grace(SVC_NET(rqstp)))
+		return nfserr_grace;
+
+	ret = nfsd_setxattr(rqstp, &cstate->current_fh, setxattr->setxa_name,
+			    setxattr->setxa_buf, setxattr->setxa_len,
+			    setxattr->setxa_flags);
+
+	if (!ret)
+		set_change_info(&setxattr->setxa_cinfo, &cstate->current_fh);
+
+	return ret;
+}
+
+static __be32
+nfsd4_listxattrs(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	   union nfsd4_op_u *u)
+{
+	/*
+	 * Get the entire list, then copy out only the user attributes
+	 * in the encode function.
+	 */
+	return nfsd_listxattr(rqstp, &cstate->current_fh,
+			     &u->listxattrs.lsxa_buf, &u->listxattrs.lsxa_len);
+}
+
+static __be32
+nfsd4_removexattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	   union nfsd4_op_u *u)
+{
+	struct nfsd4_removexattr *removexattr = &u->removexattr;
+	__be32 ret;
+
+	if (opens_in_grace(SVC_NET(rqstp)))
+		return nfserr_grace;
+
+	ret = nfsd_removexattr(rqstp, &cstate->current_fh,
+	    removexattr->rmxa_name);
+
+	if (!ret)
+		set_change_info(&removexattr->rmxa_cinfo, &cstate->current_fh);
+
+	return ret;
+}
+
 /*
  * NULL call.
  */
@@ -2700,6 +2768,42 @@ static inline u32 nfsd4_seek_rsize(struct svc_rqst *rqstp, struct nfsd4_op *op)
 	return (op_encode_hdr_size + 3) * sizeof(__be32);
 }
 
+static inline u32 nfsd4_getxattr_rsize(struct svc_rqst *rqstp,
+				       struct nfsd4_op *op)
+{
+	u32 maxcount, rlen;
+
+	maxcount = svc_max_payload(rqstp);
+	rlen = min_t(u32, XATTR_SIZE_MAX, maxcount);
+
+	return (op_encode_hdr_size + 1 + XDR_QUADLEN(rlen)) * sizeof(__be32);
+}
+
+static inline u32 nfsd4_setxattr_rsize(struct svc_rqst *rqstp,
+				       struct nfsd4_op *op)
+{
+	return (op_encode_hdr_size + op_encode_change_info_maxsz)
+		* sizeof(__be32);
+}
+static inline u32 nfsd4_listxattrs_rsize(struct svc_rqst *rqstp,
+					 struct nfsd4_op *op)
+{
+	u32 maxcount, rlen;
+
+	maxcount = svc_max_payload(rqstp);
+	rlen = min(op->u.listxattrs.lsxa_maxcount, maxcount);
+
+	return (op_encode_hdr_size + 4 + XDR_QUADLEN(rlen)) * sizeof(__be32);
+}
+
+static inline u32 nfsd4_removexattr_rsize(struct svc_rqst *rqstp,
+					  struct nfsd4_op *op)
+{
+	return (op_encode_hdr_size + op_encode_change_info_maxsz)
+		* sizeof(__be32);
+}
+
+
 static const struct nfsd4_operation nfsd4_ops[] = {
 	[OP_ACCESS] = {
 		.op_func = nfsd4_access,
@@ -3081,6 +3185,28 @@ static const struct nfsd4_operation nfsd4_ops[] = {
 		.op_name = "OP_COPY_NOTIFY",
 		.op_rsize_bop = nfsd4_copy_notify_rsize,
 	},
+	[OP_GETXATTR] = {
+		.op_func = nfsd4_getxattr,
+		.op_name = "OP_GETXATTR",
+		.op_rsize_bop = nfsd4_getxattr_rsize,
+	},
+	[OP_SETXATTR] = {
+		.op_func = nfsd4_setxattr,
+		.op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
+		.op_name = "OP_SETXATTR",
+		.op_rsize_bop = nfsd4_setxattr_rsize,
+	},
+	[OP_LISTXATTRS] = {
+		.op_func = nfsd4_listxattrs,
+		.op_name = "OP_LISTXATTRS",
+		.op_rsize_bop = nfsd4_listxattrs_rsize,
+	},
+	[OP_REMOVEXATTR] = {
+		.op_func = nfsd4_removexattr,
+		.op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
+		.op_name = "OP_REMOVEXATTR",
+		.op_rsize_bop = nfsd4_removexattr_rsize,
+	},
 };
 
 /**
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 9e40dfecf1b1..186fa2c2c6ba 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -747,13 +747,11 @@ struct cld_upcall {
 };
 
 static int
-__cld_pipe_upcall(struct rpc_pipe *pipe, void *cmsg)
+__cld_pipe_upcall(struct rpc_pipe *pipe, void *cmsg, struct nfsd_net *nn)
 {
 	int ret;
 	struct rpc_pipe_msg msg;
 	struct cld_upcall *cup = container_of(cmsg, struct cld_upcall, cu_u);
-	struct nfsd_net *nn = net_generic(pipe->dentry->d_sb->s_fs_info,
-					  nfsd_net_id);
 
 	memset(&msg, 0, sizeof(msg));
 	msg.data = cmsg;
@@ -773,7 +771,7 @@ out:
 }
 
 static int
-cld_pipe_upcall(struct rpc_pipe *pipe, void *cmsg)
+cld_pipe_upcall(struct rpc_pipe *pipe, void *cmsg, struct nfsd_net *nn)
 {
 	int ret;
 
@@ -782,7 +780,7 @@ cld_pipe_upcall(struct rpc_pipe *pipe, void *cmsg)
 	 *  upcalls queued.
 	 */
 	do {
-		ret = __cld_pipe_upcall(pipe, cmsg);
+		ret = __cld_pipe_upcall(pipe, cmsg, nn);
 	} while (ret == -EAGAIN);
 
 	return ret;
@@ -1115,7 +1113,7 @@ nfsd4_cld_create(struct nfs4_client *clp)
 	memcpy(cup->cu_u.cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
 			clp->cl_name.len);
 
-	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg);
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
 	if (!ret) {
 		ret = cup->cu_u.cu_msg.cm_status;
 		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
@@ -1180,7 +1178,7 @@ nfsd4_cld_create_v2(struct nfs4_client *clp)
 	} else
 		cmsg->cm_u.cm_clntinfo.cc_princhash.cp_len = 0;
 
-	ret = cld_pipe_upcall(cn->cn_pipe, cmsg);
+	ret = cld_pipe_upcall(cn->cn_pipe, cmsg, nn);
 	if (!ret) {
 		ret = cmsg->cm_status;
 		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
@@ -1218,7 +1216,7 @@ nfsd4_cld_remove(struct nfs4_client *clp)
 	memcpy(cup->cu_u.cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
 			clp->cl_name.len);
 
-	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg);
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
 	if (!ret) {
 		ret = cup->cu_u.cu_msg.cm_status;
 		clear_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
@@ -1261,7 +1259,7 @@ nfsd4_cld_check_v0(struct nfs4_client *clp)
 	memcpy(cup->cu_u.cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,
 			clp->cl_name.len);
 
-	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg);
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
 	if (!ret) {
 		ret = cup->cu_u.cu_msg.cm_status;
 		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);
@@ -1404,7 +1402,7 @@ nfsd4_cld_grace_start(struct nfsd_net *nn)
 	}
 
 	cup->cu_u.cu_msg.cm_cmd = Cld_GraceStart;
-	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg);
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
 	if (!ret)
 		ret = cup->cu_u.cu_msg.cm_status;
 
@@ -1432,7 +1430,7 @@ nfsd4_cld_grace_done_v0(struct nfsd_net *nn)
 
 	cup->cu_u.cu_msg.cm_cmd = Cld_GraceDone;
 	cup->cu_u.cu_msg.cm_u.cm_gracetime = nn->boot_time;
-	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg);
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
 	if (!ret)
 		ret = cup->cu_u.cu_msg.cm_status;
 
@@ -1460,7 +1458,7 @@ nfsd4_cld_grace_done(struct nfsd_net *nn)
 	}
 
 	cup->cu_u.cu_msg.cm_cmd = Cld_GraceDone;
-	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg);
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
 	if (!ret)
 		ret = cup->cu_u.cu_msg.cm_status;
 
@@ -1524,7 +1522,7 @@ nfsd4_cld_get_version(struct nfsd_net *nn)
 		goto out_err;
 	}
 	cup->cu_u.cu_msg.cm_cmd = Cld_GetVersion;
-	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg);
+	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_u.cu_msg, nn);
 	if (!ret) {
 		ret = cup->cu_u.cu_msg.cm_status;
 		if (ret)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index c9056316a0b3..81ed8e8bab3f 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4940,6 +4940,32 @@ static struct file_lock *nfs4_alloc_init_lease(struct nfs4_delegation *dp,
 	return fl;
 }
 
+static int nfsd4_check_conflicting_opens(struct nfs4_client *clp,
+						struct nfs4_file *fp)
+{
+	struct nfs4_clnt_odstate *co;
+	struct file *f = fp->fi_deleg_file->nf_file;
+	struct inode *ino = locks_inode(f);
+	int writes = atomic_read(&ino->i_writecount);
+
+	if (fp->fi_fds[O_WRONLY])
+		writes--;
+	if (fp->fi_fds[O_RDWR])
+		writes--;
+	WARN_ON_ONCE(writes < 0);
+	if (writes > 0)
+		return -EAGAIN;
+	spin_lock(&fp->fi_lock);
+	list_for_each_entry(co, &fp->fi_clnt_odstate, co_perfile) {
+		if (co->co_client != clp) {
+			spin_unlock(&fp->fi_lock);
+			return -EAGAIN;
+		}
+	}
+	spin_unlock(&fp->fi_lock);
+	return 0;
+}
+
 static struct nfs4_delegation *
 nfs4_set_delegation(struct nfs4_client *clp, struct svc_fh *fh,
 		    struct nfs4_file *fp, struct nfs4_clnt_odstate *odstate)
@@ -4959,9 +4985,12 @@ nfs4_set_delegation(struct nfs4_client *clp, struct svc_fh *fh,
 
 	nf = find_readable_file(fp);
 	if (!nf) {
-		/* We should always have a readable file here */
-		WARN_ON_ONCE(1);
-		return ERR_PTR(-EBADF);
+		/*
+		 * We probably could attempt another open and get a read
+		 * delegation, but for now, don't bother until the
+		 * client actually sends us one.
+		 */
+		return ERR_PTR(-EAGAIN);
 	}
 	spin_lock(&state_lock);
 	spin_lock(&fp->fi_lock);
@@ -4991,11 +5020,19 @@ nfs4_set_delegation(struct nfs4_client *clp, struct svc_fh *fh,
 	if (!fl)
 		goto out_clnt_odstate;
 
+	status = nfsd4_check_conflicting_opens(clp, fp);
+	if (status) {
+		locks_free_lock(fl);
+		goto out_clnt_odstate;
+	}
 	status = vfs_setlease(fp->fi_deleg_file->nf_file, fl->fl_type, &fl, NULL);
 	if (fl)
 		locks_free_lock(fl);
 	if (status)
 		goto out_clnt_odstate;
+	status = nfsd4_check_conflicting_opens(clp, fp);
+	if (status)
+		goto out_clnt_odstate;
 
 	spin_lock(&state_lock);
 	spin_lock(&fp->fi_lock);
@@ -5077,17 +5114,6 @@ nfs4_open_delegation(struct svc_fh *fh, struct nfsd4_open *open,
 				goto out_no_deleg;
 			if (!cb_up || !(oo->oo_flags & NFS4_OO_CONFIRMED))
 				goto out_no_deleg;
-			/*
-			 * Also, if the file was opened for write or
-			 * create, there's a good chance the client's
-			 * about to write to it, resulting in an
-			 * immediate recall (since we don't support
-			 * write delegations):
-			 */
-			if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE)
-				goto out_no_deleg;
-			if (open->op_create == NFS4_OPEN_CREATE)
-				goto out_no_deleg;
 			break;
 		default:
 			goto out_no_deleg;
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 996ac01ee977..259d5ad0e3f4 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -41,6 +41,8 @@
 #include <linux/pagemap.h>
 #include <linux/sunrpc/svcauth_gss.h>
 #include <linux/sunrpc/addr.h>
+#include <linux/xattr.h>
+#include <uapi/linux/xattr.h>
 
 #include "idmap.h"
 #include "acl.h"
@@ -257,6 +259,44 @@ svcxdr_dupstr(struct nfsd4_compoundargs *argp, void *buf, u32 len)
 	return p;
 }
 
+static __be32
+svcxdr_construct_vector(struct nfsd4_compoundargs *argp, struct kvec *head,
+			struct page ***pagelist, u32 buflen)
+{
+	int avail;
+	int len;
+	int pages;
+
+	/* Sorry .. no magic macros for this.. *
+	 * READ_BUF(write->wr_buflen);
+	 * SAVEMEM(write->wr_buf, write->wr_buflen);
+	 */
+	avail = (char *)argp->end - (char *)argp->p;
+	if (avail + argp->pagelen < buflen) {
+		dprintk("NFSD: xdr error (%s:%d)\n",
+			       __FILE__, __LINE__);
+		return nfserr_bad_xdr;
+	}
+	head->iov_base = argp->p;
+	head->iov_len = avail;
+	*pagelist = argp->pagelist;
+
+	len = XDR_QUADLEN(buflen) << 2;
+	if (len >= avail) {
+		len -= avail;
+
+		pages = len >> PAGE_SHIFT;
+		argp->pagelist += pages;
+		argp->pagelen -= pages * PAGE_SIZE;
+		len -= pages * PAGE_SIZE;
+
+		next_decode_page(argp);
+	}
+	argp->p += XDR_QUADLEN(len);
+
+	return 0;
+}
+
 /**
  * savemem - duplicate a chunk of memory for later processing
  * @argp: NFSv4 compound argument structure to be freed with
@@ -1265,8 +1305,6 @@ nfsd4_decode_verify(struct nfsd4_compoundargs *argp, struct nfsd4_verify *verify
 static __be32
 nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
 {
-	int avail;
-	int len;
 	DECODE_HEAD;
 
 	status = nfsd4_decode_stateid(argp, &write->wr_stateid);
@@ -1279,34 +1317,10 @@ nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
 		goto xdr_error;
 	write->wr_buflen = be32_to_cpup(p++);
 
-	/* Sorry .. no magic macros for this.. *
-	 * READ_BUF(write->wr_buflen);
-	 * SAVEMEM(write->wr_buf, write->wr_buflen);
-	 */
-	avail = (char*)argp->end - (char*)argp->p;
-	if (avail + argp->pagelen < write->wr_buflen) {
-		dprintk("NFSD: xdr error (%s:%d)\n",
-				__FILE__, __LINE__);
-		goto xdr_error;
-	}
-	write->wr_head.iov_base = p;
-	write->wr_head.iov_len = avail;
-	write->wr_pagelist = argp->pagelist;
-
-	len = XDR_QUADLEN(write->wr_buflen) << 2;
-	if (len >= avail) {
-		int pages;
-
-		len -= avail;
-
-		pages = len >> PAGE_SHIFT;
-		argp->pagelist += pages;
-		argp->pagelen -= pages * PAGE_SIZE;
-		len -= pages * PAGE_SIZE;
-
-		next_decode_page(argp);
-	}
-	argp->p += XDR_QUADLEN(len);
+	status = svcxdr_construct_vector(argp, &write->wr_head,
+					 &write->wr_pagelist, write->wr_buflen);
+	if (status)
+		return status;
 
 	DECODE_TAIL;
 }
@@ -1865,6 +1879,208 @@ nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek)
 	DECODE_TAIL;
 }
 
+/*
+ * XDR data that is more than PAGE_SIZE in size is normally part of a
+ * read or write. However, the size of extended attributes is limited
+ * by the maximum request size, and then further limited by the underlying
+ * filesystem limits. This can exceed PAGE_SIZE (currently, XATTR_SIZE_MAX
+ * is 64k). Since there is no kvec- or page-based interface to xattrs,
+ * and we're not dealing with contiguous pages, we need to do some copying.
+ */
+
+/*
+ * Decode data into buffer. Uses head and pages constructed by
+ * svcxdr_construct_vector.
+ */
+static __be32
+nfsd4_vbuf_from_vector(struct nfsd4_compoundargs *argp, struct kvec *head,
+		       struct page **pages, char **bufp, u32 buflen)
+{
+	char *tmp, *dp;
+	u32 len;
+
+	if (buflen <= head->iov_len) {
+		/*
+		 * We're in luck, the head has enough space. Just return
+		 * the head, no need for copying.
+		 */
+		*bufp = head->iov_base;
+		return 0;
+	}
+
+	tmp = svcxdr_tmpalloc(argp, buflen);
+	if (tmp == NULL)
+		return nfserr_jukebox;
+
+	dp = tmp;
+	memcpy(dp, head->iov_base, head->iov_len);
+	buflen -= head->iov_len;
+	dp += head->iov_len;
+
+	while (buflen > 0) {
+		len = min_t(u32, buflen, PAGE_SIZE);
+		memcpy(dp, page_address(*pages), len);
+
+		buflen -= len;
+		dp += len;
+		pages++;
+	}
+
+	*bufp = tmp;
+	return 0;
+}
+
+/*
+ * Get a user extended attribute name from the XDR buffer.
+ * It will not have the "user." prefix, so prepend it.
+ * Lastly, check for nul characters in the name.
+ */
+static __be32
+nfsd4_decode_xattr_name(struct nfsd4_compoundargs *argp, char **namep)
+{
+	DECODE_HEAD;
+	char *name, *sp, *dp;
+	u32 namelen, cnt;
+
+	READ_BUF(4);
+	namelen = be32_to_cpup(p++);
+
+	if (namelen > (XATTR_NAME_MAX - XATTR_USER_PREFIX_LEN))
+		return nfserr_nametoolong;
+
+	if (namelen == 0)
+		goto xdr_error;
+
+	READ_BUF(namelen);
+
+	name = svcxdr_tmpalloc(argp, namelen + XATTR_USER_PREFIX_LEN + 1);
+	if (!name)
+		return nfserr_jukebox;
+
+	memcpy(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
+
+	/*
+	 * Copy the extended attribute name over while checking for 0
+	 * characters.
+	 */
+	sp = (char *)p;
+	dp = name + XATTR_USER_PREFIX_LEN;
+	cnt = namelen;
+
+	while (cnt-- > 0) {
+		if (*sp == '\0')
+			goto xdr_error;
+		*dp++ = *sp++;
+	}
+	*dp = '\0';
+
+	*namep = name;
+
+	DECODE_TAIL;
+}
+
+/*
+ * A GETXATTR op request comes without a length specifier. We just set the
+ * maximum length for the reply based on XATTR_SIZE_MAX and the maximum
+ * channel reply size. nfsd_getxattr will probe the length of the xattr,
+ * check it against getxa_len, and allocate + return the value.
+ */
+static __be32
+nfsd4_decode_getxattr(struct nfsd4_compoundargs *argp,
+		      struct nfsd4_getxattr *getxattr)
+{
+	__be32 status;
+	u32 maxcount;
+
+	status = nfsd4_decode_xattr_name(argp, &getxattr->getxa_name);
+	if (status)
+		return status;
+
+	maxcount = svc_max_payload(argp->rqstp);
+	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
+
+	getxattr->getxa_len = maxcount;
+
+	return status;
+}
+
+static __be32
+nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
+		      struct nfsd4_setxattr *setxattr)
+{
+	DECODE_HEAD;
+	u32 flags, maxcount, size;
+	struct kvec head;
+	struct page **pagelist;
+
+	READ_BUF(4);
+	flags = be32_to_cpup(p++);
+
+	if (flags > SETXATTR4_REPLACE)
+		return nfserr_inval;
+	setxattr->setxa_flags = flags;
+
+	status = nfsd4_decode_xattr_name(argp, &setxattr->setxa_name);
+	if (status)
+		return status;
+
+	maxcount = svc_max_payload(argp->rqstp);
+	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
+
+	READ_BUF(4);
+	size = be32_to_cpup(p++);
+	if (size > maxcount)
+		return nfserr_xattr2big;
+
+	setxattr->setxa_len = size;
+	if (size > 0) {
+		status = svcxdr_construct_vector(argp, &head, &pagelist, size);
+		if (status)
+			return status;
+
+		status = nfsd4_vbuf_from_vector(argp, &head, pagelist,
+		    &setxattr->setxa_buf, size);
+	}
+
+	DECODE_TAIL;
+}
+
+static __be32
+nfsd4_decode_listxattrs(struct nfsd4_compoundargs *argp,
+			struct nfsd4_listxattrs *listxattrs)
+{
+	DECODE_HEAD;
+	u32 maxcount;
+
+	READ_BUF(12);
+	p = xdr_decode_hyper(p, &listxattrs->lsxa_cookie);
+
+	/*
+	 * If the cookie  is too large to have even one user.x attribute
+	 * plus trailing '\0' left in a maximum size buffer, it's invalid.
+	 */
+	if (listxattrs->lsxa_cookie >=
+	    (XATTR_LIST_MAX / (XATTR_USER_PREFIX_LEN + 2)))
+		return nfserr_badcookie;
+
+	maxcount = be32_to_cpup(p++);
+	if (maxcount < 8)
+		/* Always need at least 2 words (length and one character) */
+		return nfserr_inval;
+
+	maxcount = min(maxcount, svc_max_payload(argp->rqstp));
+	listxattrs->lsxa_maxcount = maxcount;
+
+	DECODE_TAIL;
+}
+
+static __be32
+nfsd4_decode_removexattr(struct nfsd4_compoundargs *argp,
+			 struct nfsd4_removexattr *removexattr)
+{
+	return nfsd4_decode_xattr_name(argp, &removexattr->rmxa_name);
+}
+
 static __be32
 nfsd4_decode_noop(struct nfsd4_compoundargs *argp, void *p)
 {
@@ -1961,6 +2177,11 @@ static const nfsd4_dec nfsd4_dec_ops[] = {
 	[OP_SEEK]		= (nfsd4_dec)nfsd4_decode_seek,
 	[OP_WRITE_SAME]		= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_CLONE]		= (nfsd4_dec)nfsd4_decode_clone,
+	/* RFC 8276 extended atributes operations */
+	[OP_GETXATTR]		= (nfsd4_dec)nfsd4_decode_getxattr,
+	[OP_SETXATTR]		= (nfsd4_dec)nfsd4_decode_setxattr,
+	[OP_LISTXATTRS]		= (nfsd4_dec)nfsd4_decode_listxattrs,
+	[OP_REMOVEXATTR]	= (nfsd4_dec)nfsd4_decode_removexattr,
 };
 
 static inline bool
@@ -2992,6 +3213,15 @@ out_acl:
 	}
 #endif
 
+	if (bmval2 & FATTR4_WORD2_XATTR_SUPPORT) {
+		p = xdr_reserve_space(xdr, 4);
+		if (!p)
+			goto out_resource;
+		err = xattr_supported_namespace(d_inode(dentry),
+						XATTR_USER_PREFIX);
+		*p++ = cpu_to_be32(err == 0);
+	}
+
 	attrlen = htonl(xdr->buf->len - attrlen_offset - 4);
 	write_bytes_to_xdr_buf(xdr->buf, attrlen_offset, &attrlen, 4);
 	status = nfs_ok;
@@ -4446,6 +4676,241 @@ nfsd4_encode_noop(struct nfsd4_compoundres *resp, __be32 nfserr, void *p)
 	return nfserr;
 }
 
+/*
+ * Encode kmalloc-ed buffer in to XDR stream.
+ */
+static int
+nfsd4_vbuf_to_stream(struct xdr_stream *xdr, char *buf, u32 buflen)
+{
+	u32 cplen;
+	__be32 *p;
+
+	cplen = min_t(unsigned long, buflen,
+		      ((void *)xdr->end - (void *)xdr->p));
+	p = xdr_reserve_space(xdr, cplen);
+	if (!p)
+		return nfserr_resource;
+
+	memcpy(p, buf, cplen);
+	buf += cplen;
+	buflen -= cplen;
+
+	while (buflen) {
+		cplen = min_t(u32, buflen, PAGE_SIZE);
+		p = xdr_reserve_space(xdr, cplen);
+		if (!p)
+			return nfserr_resource;
+
+		memcpy(p, buf, cplen);
+
+		if (cplen < PAGE_SIZE) {
+			/*
+			 * We're done, with a length that wasn't page
+			 * aligned, so possibly not word aligned. Pad
+			 * any trailing bytes with 0.
+			 */
+			xdr_encode_opaque_fixed(p, NULL, cplen);
+			break;
+		}
+
+		buflen -= PAGE_SIZE;
+		buf += PAGE_SIZE;
+	}
+
+	return 0;
+}
+
+static __be32
+nfsd4_encode_getxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
+		      struct nfsd4_getxattr *getxattr)
+{
+	struct xdr_stream *xdr = &resp->xdr;
+	__be32 *p, err;
+
+	p = xdr_reserve_space(xdr, 4);
+	if (!p)
+		return nfserr_resource;
+
+	*p = cpu_to_be32(getxattr->getxa_len);
+
+	if (getxattr->getxa_len == 0)
+		return 0;
+
+	err = nfsd4_vbuf_to_stream(xdr, getxattr->getxa_buf,
+				    getxattr->getxa_len);
+
+	kvfree(getxattr->getxa_buf);
+
+	return err;
+}
+
+static __be32
+nfsd4_encode_setxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
+		      struct nfsd4_setxattr *setxattr)
+{
+	struct xdr_stream *xdr = &resp->xdr;
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, 20);
+	if (!p)
+		return nfserr_resource;
+
+	encode_cinfo(p, &setxattr->setxa_cinfo);
+
+	return 0;
+}
+
+/*
+ * See if there are cookie values that can be rejected outright.
+ */
+static __be32
+nfsd4_listxattr_validate_cookie(struct nfsd4_listxattrs *listxattrs,
+				u32 *offsetp)
+{
+	u64 cookie = listxattrs->lsxa_cookie;
+
+	/*
+	 * If the cookie is larger than the maximum number we can fit
+	 * in either the buffer we just got back from vfs_listxattr, or,
+	 * XDR-encoded, in the return buffer, it's invalid.
+	 */
+	if (cookie > (listxattrs->lsxa_len) / (XATTR_USER_PREFIX_LEN + 2))
+		return nfserr_badcookie;
+
+	if (cookie > (listxattrs->lsxa_maxcount /
+		      (XDR_QUADLEN(XATTR_USER_PREFIX_LEN + 2) + 4)))
+		return nfserr_badcookie;
+
+	*offsetp = (u32)cookie;
+	return 0;
+}
+
+static __be32
+nfsd4_encode_listxattrs(struct nfsd4_compoundres *resp, __be32 nfserr,
+			struct nfsd4_listxattrs *listxattrs)
+{
+	struct xdr_stream *xdr = &resp->xdr;
+	u32 cookie_offset, count_offset, eof;
+	u32 left, xdrleft, slen, count;
+	u32 xdrlen, offset;
+	u64 cookie;
+	char *sp;
+	__be32 status;
+	__be32 *p;
+	u32 nuser;
+
+	eof = 1;
+
+	status = nfsd4_listxattr_validate_cookie(listxattrs, &offset);
+	if (status)
+		goto out;
+
+	/*
+	 * Reserve space for the cookie and the name array count. Record
+	 * the offsets to save them later.
+	 */
+	cookie_offset = xdr->buf->len;
+	count_offset = cookie_offset + 8;
+	p = xdr_reserve_space(xdr, 12);
+	if (!p) {
+		status = nfserr_resource;
+		goto out;
+	}
+
+	count = 0;
+	left = listxattrs->lsxa_len;
+	sp = listxattrs->lsxa_buf;
+	nuser = 0;
+
+	xdrleft = listxattrs->lsxa_maxcount;
+
+	while (left > 0 && xdrleft > 0) {
+		slen = strlen(sp);
+
+		/*
+		 * Check if this a user. attribute, skip it if not.
+		 */
+		if (strncmp(sp, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
+			goto contloop;
+
+		slen -= XATTR_USER_PREFIX_LEN;
+		xdrlen = 4 + ((slen + 3) & ~3);
+		if (xdrlen > xdrleft) {
+			if (count == 0) {
+				/*
+				 * Can't even fit the first attribute name.
+				 */
+				status = nfserr_toosmall;
+				goto out;
+			}
+			eof = 0;
+			goto wreof;
+		}
+
+		left -= XATTR_USER_PREFIX_LEN;
+		sp += XATTR_USER_PREFIX_LEN;
+		if (nuser++ < offset)
+			goto contloop;
+
+
+		p = xdr_reserve_space(xdr, xdrlen);
+		if (!p) {
+			status = nfserr_resource;
+			goto out;
+		}
+
+		p = xdr_encode_opaque(p, sp, slen);
+
+		xdrleft -= xdrlen;
+		count++;
+contloop:
+		sp += slen + 1;
+		left -= slen + 1;
+	}
+
+	/*
+	 * If there were user attributes to copy, but we didn't copy
+	 * any, the offset was too large (e.g. the cookie was invalid).
+	 */
+	if (nuser > 0 && count == 0) {
+		status = nfserr_badcookie;
+		goto out;
+	}
+
+wreof:
+	p = xdr_reserve_space(xdr, 4);
+	if (!p) {
+		status = nfserr_resource;
+		goto out;
+	}
+	*p = cpu_to_be32(eof);
+
+	cookie = offset + count;
+
+	write_bytes_to_xdr_buf(xdr->buf, cookie_offset, &cookie, 8);
+	count = htonl(count);
+	write_bytes_to_xdr_buf(xdr->buf, count_offset, &count, 4);
+out:
+	if (listxattrs->lsxa_len)
+		kvfree(listxattrs->lsxa_buf);
+	return status;
+}
+
+static __be32
+nfsd4_encode_removexattr(struct nfsd4_compoundres *resp, __be32 nfserr,
+			 struct nfsd4_removexattr *removexattr)
+{
+	struct xdr_stream *xdr = &resp->xdr;
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, 20);
+	if (!p)
+		return nfserr_resource;
+
+	p = encode_cinfo(p, &removexattr->rmxa_cinfo);
+	return 0;
+}
+
 typedef __be32(* nfsd4_enc)(struct nfsd4_compoundres *, __be32, void *);
 
 /*
@@ -4535,6 +5000,12 @@ static const nfsd4_enc nfsd4_enc_ops[] = {
 	[OP_SEEK]		= (nfsd4_enc)nfsd4_encode_seek,
 	[OP_WRITE_SAME]		= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_CLONE]		= (nfsd4_enc)nfsd4_encode_noop,
+
+	/* RFC 8276 extended atributes operations */
+	[OP_GETXATTR]		= (nfsd4_enc)nfsd4_encode_getxattr,
+	[OP_SETXATTR]		= (nfsd4_enc)nfsd4_encode_setxattr,
+	[OP_LISTXATTRS]		= (nfsd4_enc)nfsd4_encode_listxattrs,
+	[OP_REMOVEXATTR]	= (nfsd4_enc)nfsd4_encode_removexattr,
 };
 
 /*
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 57c832d1b30f..cb742e17e04a 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -286,6 +286,8 @@ void		nfsd_lockd_shutdown(void);
 #define nfserr_wrong_lfs		cpu_to_be32(NFS4ERR_WRONG_LFS)
 #define nfserr_badlabel			cpu_to_be32(NFS4ERR_BADLABEL)
 #define nfserr_file_open		cpu_to_be32(NFS4ERR_FILE_OPEN)
+#define nfserr_xattr2big		cpu_to_be32(NFS4ERR_XATTR2BIG)
+#define nfserr_noxattr			cpu_to_be32(NFS4ERR_NOXATTR)
 
 /* error codes for internal use */
 /* if a request fails due to kmalloc failure, it gets dropped.
@@ -387,7 +389,8 @@ void		nfsd_lockd_shutdown(void);
 	(NFSD4_1_SUPPORTED_ATTRS_WORD2 | \
 	FATTR4_WORD2_CHANGE_ATTR_TYPE | \
 	FATTR4_WORD2_MODE_UMASK | \
-	NFSD4_2_SECURITY_ATTRS)
+	NFSD4_2_SECURITY_ATTRS | \
+	FATTR4_WORD2_XATTR_SUPPORT)
 
 extern const u32 nfsd_suppattrs[3][3];
 
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index d22a056da477..7d2933b85b65 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -612,6 +612,12 @@ static struct accessmap	nfs3_regaccess[] = {
     {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_TRUNC	},
     {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE			},
 
+#ifdef CONFIG_NFSD_V4
+    {	NFS4_ACCESS_XAREAD,	NFSD_MAY_READ			},
+    {	NFS4_ACCESS_XAWRITE,	NFSD_MAY_WRITE			},
+    {	NFS4_ACCESS_XALIST,	NFSD_MAY_READ			},
+#endif
+
     {	0,			0				}
 };
 
@@ -622,6 +628,12 @@ static struct accessmap	nfs3_diraccess[] = {
     {	NFS3_ACCESS_EXTEND,	NFSD_MAY_EXEC|NFSD_MAY_WRITE	},
     {	NFS3_ACCESS_DELETE,	NFSD_MAY_REMOVE			},
 
+#ifdef CONFIG_NFSD_V4
+    {	NFS4_ACCESS_XAREAD,	NFSD_MAY_READ			},
+    {	NFS4_ACCESS_XAWRITE,	NFSD_MAY_WRITE			},
+    {	NFS4_ACCESS_XALIST,	NFSD_MAY_READ			},
+#endif
+
     {	0,			0				}
 };
 
@@ -2065,6 +2077,233 @@ static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
 	return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
 }
 
+#ifdef CONFIG_NFSD_V4
+/*
+ * Helper function to translate error numbers. In the case of xattr operations,
+ * some error codes need to be translated outside of the standard translations.
+ *
+ * ENODATA needs to be translated to nfserr_noxattr.
+ * E2BIG to nfserr_xattr2big.
+ *
+ * Additionally, vfs_listxattr can return -ERANGE. This means that the
+ * file has too many extended attributes to retrieve inside an
+ * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation:
+ * filesystems will allow the adding of extended attributes until they hit
+ * their own internal limit. This limit may be larger than XATTR_LIST_MAX.
+ * So, at that point, the attributes are present and valid, but can't
+ * be retrieved using listxattr, since the upper level xattr code enforces
+ * the XATTR_LIST_MAX limit.
+ *
+ * This bug means that we need to deal with listxattr returning -ERANGE. The
+ * best mapping is to return TOOSMALL.
+ */
+static __be32
+nfsd_xattr_errno(int err)
+{
+	switch (err) {
+	case -ENODATA:
+		return nfserr_noxattr;
+	case -E2BIG:
+		return nfserr_xattr2big;
+	case -ERANGE:
+		return nfserr_toosmall;
+	}
+	return nfserrno(err);
+}
+
+/*
+ * Retrieve the specified user extended attribute. To avoid always
+ * having to allocate the maximum size (since we are not getting
+ * a maximum size from the RPC), do a probe + alloc. Hold a reader
+ * lock on i_rwsem to prevent the extended attribute from changing
+ * size while we're doing this.
+ */
+__be32
+nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
+	      void **bufp, int *lenp)
+{
+	ssize_t len;
+	__be32 err;
+	char *buf;
+	struct inode *inode;
+	struct dentry *dentry;
+
+	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
+	if (err)
+		return err;
+
+	err = nfs_ok;
+	dentry = fhp->fh_dentry;
+	inode = d_inode(dentry);
+
+	inode_lock_shared(inode);
+
+	len = vfs_getxattr(dentry, name, NULL, 0);
+
+	/*
+	 * Zero-length attribute, just return.
+	 */
+	if (len == 0) {
+		*bufp = NULL;
+		*lenp = 0;
+		goto out;
+	}
+
+	if (len < 0) {
+		err = nfsd_xattr_errno(len);
+		goto out;
+	}
+
+	if (len > *lenp) {
+		err = nfserr_toosmall;
+		goto out;
+	}
+
+	buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS);
+	if (buf == NULL) {
+		err = nfserr_jukebox;
+		goto out;
+	}
+
+	len = vfs_getxattr(dentry, name, buf, len);
+	if (len <= 0) {
+		kvfree(buf);
+		buf = NULL;
+		err = nfsd_xattr_errno(len);
+	}
+
+	*lenp = len;
+	*bufp = buf;
+
+out:
+	inode_unlock_shared(inode);
+
+	return err;
+}
+
+/*
+ * Retrieve the xattr names. Since we can't know how many are
+ * user extended attributes, we must get all attributes here,
+ * and have the XDR encode filter out the "user." ones.
+ *
+ * While this could always just allocate an XATTR_LIST_MAX
+ * buffer, that's a waste, so do a probe + allocate. To
+ * avoid any changes between the probe and allocate, wrap
+ * this in inode_lock.
+ */
+__be32
+nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp,
+	       int *lenp)
+{
+	ssize_t len;
+	__be32 err;
+	char *buf;
+	struct inode *inode;
+	struct dentry *dentry;
+
+	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
+	if (err)
+		return err;
+
+	dentry = fhp->fh_dentry;
+	inode = d_inode(dentry);
+	*lenp = 0;
+
+	inode_lock_shared(inode);
+
+	len = vfs_listxattr(dentry, NULL, 0);
+	if (len <= 0) {
+		err = nfsd_xattr_errno(len);
+		goto out;
+	}
+
+	if (len > XATTR_LIST_MAX) {
+		err = nfserr_xattr2big;
+		goto out;
+	}
+
+	/*
+	 * We're holding i_rwsem - use GFP_NOFS.
+	 */
+	buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS);
+	if (buf == NULL) {
+		err = nfserr_jukebox;
+		goto out;
+	}
+
+	len = vfs_listxattr(dentry, buf, len);
+	if (len <= 0) {
+		kvfree(buf);
+		err = nfsd_xattr_errno(len);
+		goto out;
+	}
+
+	*lenp = len;
+	*bufp = buf;
+
+	err = nfs_ok;
+out:
+	inode_unlock_shared(inode);
+
+	return err;
+}
+
+/*
+ * Removexattr and setxattr need to call fh_lock to both lock the inode
+ * and set the change attribute. Since the top-level vfs_removexattr
+ * and vfs_setxattr calls already do their own inode_lock calls, call
+ * the _locked variant. Pass in a NULL pointer for delegated_inode,
+ * and let the client deal with NFS4ERR_DELAY (same as with e.g.
+ * setattr and remove).
+ */
+__be32
+nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
+{
+	int err, ret;
+
+	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
+	if (err)
+		return err;
+
+	ret = fh_want_write(fhp);
+	if (ret)
+		return nfserrno(ret);
+
+	fh_lock(fhp);
+
+	ret = __vfs_removexattr_locked(fhp->fh_dentry, name, NULL);
+
+	fh_unlock(fhp);
+	fh_drop_write(fhp);
+
+	return nfsd_xattr_errno(ret);
+}
+
+__be32
+nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
+	      void *buf, u32 len, u32 flags)
+{
+	int err, ret;
+
+	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
+	if (err)
+		return err;
+
+	ret = fh_want_write(fhp);
+	if (ret)
+		return nfserrno(ret);
+	fh_lock(fhp);
+
+	ret = __vfs_setxattr_locked(fhp->fh_dentry, name, buf, len, flags,
+				    NULL);
+
+	fh_unlock(fhp);
+	fh_drop_write(fhp);
+
+	return nfsd_xattr_errno(ret);
+}
+#endif
+
 /*
  * Check for a user's access permissions to this inode.
  */
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index 3eb660ad80d1..a2442ebe5acf 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -76,6 +76,16 @@ __be32		do_nfsd_create(struct svc_rqst *, struct svc_fh *,
 __be32		nfsd_commit(struct svc_rqst *, struct svc_fh *,
 				loff_t, unsigned long, __be32 *verf);
 #endif /* CONFIG_NFSD_V3 */
+#ifdef CONFIG_NFSD_V4
+__be32		nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
+			    char *name, void **bufp, int *lenp);
+__be32		nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
+			    char **bufp, int *lenp);
+__be32		nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
+			    char *name);
+__be32		nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
+			    char *name, void *buf, u32 len, u32 flags);
+#endif
 int 		nfsd_open_break_lease(struct inode *, int);
 __be32		nfsd_open(struct svc_rqst *, struct svc_fh *, umode_t,
 				int, struct file **);
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index db63d39b1507..66499fb6b567 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -224,6 +224,32 @@ struct nfsd4_putfh {
 	bool		no_verify;	    /* represents foreigh fh */
 };
 
+struct nfsd4_getxattr {
+	char		*getxa_name;		/* request */
+	u32		getxa_len;		/* request */
+	void		*getxa_buf;
+};
+
+struct nfsd4_setxattr {
+	u32		setxa_flags;		/* request */
+	char		*setxa_name;		/* request */
+	char		*setxa_buf;		/* request */
+	u32		setxa_len;		/* request */
+	struct nfsd4_change_info  setxa_cinfo;	/* response */
+};
+
+struct nfsd4_removexattr {
+	char		*rmxa_name;		/* request */
+	struct nfsd4_change_info  rmxa_cinfo;	/* response */
+};
+
+struct nfsd4_listxattrs {
+	u64		lsxa_cookie;		/* request */
+	u32		lsxa_maxcount;		/* request */
+	char		*lsxa_buf;		/* unfiltered buffer (reply) */
+	u32		lsxa_len;		/* unfiltered len (reply) */
+};
+
 struct nfsd4_open {
 	u32		op_claim_type;      /* request */
 	struct xdr_netobj op_fname;	    /* request - everything but CLAIM_PREV */
@@ -649,6 +675,11 @@ struct nfsd4_op {
 		struct nfsd4_offload_status	offload_status;
 		struct nfsd4_copy_notify	copy_notify;
 		struct nfsd4_seek		seek;
+
+		struct nfsd4_getxattr		getxattr;
+		struct nfsd4_setxattr		setxattr;
+		struct nfsd4_listxattrs		listxattrs;
+		struct nfsd4_removexattr	removexattr;
 	} u;
 	struct nfs4_replay *			replay;
 };
diff --git a/fs/xattr.c b/fs/xattr.c
index 91608d9bfc6a..386b45676d7e 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -134,6 +134,33 @@ xattr_permission(struct inode *inode, const char *name, int mask)
 	return inode_permission(inode, mask);
 }
 
+/*
+ * Look for any handler that deals with the specified namespace.
+ */
+int
+xattr_supported_namespace(struct inode *inode, const char *prefix)
+{
+	const struct xattr_handler **handlers = inode->i_sb->s_xattr;
+	const struct xattr_handler *handler;
+	size_t preflen;
+
+	if (!(inode->i_opflags & IOP_XATTR)) {
+		if (unlikely(is_bad_inode(inode)))
+			return -EIO;
+		return -EOPNOTSUPP;
+	}
+
+	preflen = strlen(prefix);
+
+	for_each_xattr_handler(handlers, handler) {
+		if (!strncmp(xattr_prefix(handler), prefix, preflen))
+			return 0;
+	}
+
+	return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL(xattr_supported_namespace);
+
 int
 __vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name,
 	       const void *value, size_t size, int flags)
@@ -204,10 +231,22 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
 	return error;
 }
 
-
+/**
+ * __vfs_setxattr_locked: set an extended attribute while holding the inode
+ * lock
+ *
+ *  @dentry - object to perform setxattr on
+ *  @name - xattr name to set
+ *  @value - value to set @name to
+ *  @size - size of @value
+ *  @flags - flags to pass into filesystem operations
+ *  @delegated_inode - on return, will contain an inode pointer that
+ *  a delegation was broken on, NULL if none.
+ */
 int
-vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
-		size_t size, int flags)
+__vfs_setxattr_locked(struct dentry *dentry, const char *name,
+		const void *value, size_t size, int flags,
+		struct inode **delegated_inode)
 {
 	struct inode *inode = dentry->d_inode;
 	int error;
@@ -216,15 +255,40 @@ vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 	if (error)
 		return error;
 
-	inode_lock(inode);
 	error = security_inode_setxattr(dentry, name, value, size, flags);
 	if (error)
 		goto out;
 
+	error = try_break_deleg(inode, delegated_inode);
+	if (error)
+		goto out;
+
 	error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
 
 out:
+	return error;
+}
+EXPORT_SYMBOL_GPL(__vfs_setxattr_locked);
+
+int
+vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+		size_t size, int flags)
+{
+	struct inode *inode = dentry->d_inode;
+	struct inode *delegated_inode = NULL;
+	int error;
+
+retry_deleg:
+	inode_lock(inode);
+	error = __vfs_setxattr_locked(dentry, name, value, size, flags,
+	    &delegated_inode);
 	inode_unlock(inode);
+
+	if (delegated_inode) {
+		error = break_deleg_wait(&delegated_inode);
+		if (!error)
+			goto retry_deleg;
+	}
 	return error;
 }
 EXPORT_SYMBOL_GPL(vfs_setxattr);
@@ -378,8 +442,18 @@ __vfs_removexattr(struct dentry *dentry, const char *name)
 }
 EXPORT_SYMBOL(__vfs_removexattr);
 
+/**
+ * __vfs_removexattr_locked: set an extended attribute while holding the inode
+ * lock
+ *
+ *  @dentry - object to perform setxattr on
+ *  @name - name of xattr to remove
+ *  @delegated_inode - on return, will contain an inode pointer that
+ *  a delegation was broken on, NULL if none.
+ */
 int
-vfs_removexattr(struct dentry *dentry, const char *name)
+__vfs_removexattr_locked(struct dentry *dentry, const char *name,
+		struct inode **delegated_inode)
 {
 	struct inode *inode = dentry->d_inode;
 	int error;
@@ -388,11 +462,14 @@ vfs_removexattr(struct dentry *dentry, const char *name)
 	if (error)
 		return error;
 
-	inode_lock(inode);
 	error = security_inode_removexattr(dentry, name);
 	if (error)
 		goto out;
 
+	error = try_break_deleg(inode, delegated_inode);
+	if (error)
+		goto out;
+
 	error = __vfs_removexattr(dentry, name);
 
 	if (!error) {
@@ -401,12 +478,32 @@ vfs_removexattr(struct dentry *dentry, const char *name)
 	}
 
 out:
+	return error;
+}
+EXPORT_SYMBOL_GPL(__vfs_removexattr_locked);
+
+int
+vfs_removexattr(struct dentry *dentry, const char *name)
+{
+	struct inode *inode = dentry->d_inode;
+	struct inode *delegated_inode = NULL;
+	int error;
+
+retry_deleg:
+	inode_lock(inode);
+	error = __vfs_removexattr_locked(dentry, name, &delegated_inode);
 	inode_unlock(inode);
+
+	if (delegated_inode) {
+		error = break_deleg_wait(&delegated_inode);
+		if (!error)
+			goto retry_deleg;
+	}
+
 	return error;
 }
 EXPORT_SYMBOL_GPL(vfs_removexattr);
 
-
 /*
  * Extended attribute SET operations
  */