diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 0beb023..a261f18 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1014,6 +1014,36 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 }
 
 static __be32
+nfsd4_fallocate(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+		struct nfsd4_fallocate *fallocate, int flags)
+{
+	__be32 status = nfserr_notsupp;
+	struct file *file;
+
+	status = nfs4_preprocess_stateid_op(SVC_NET(rqstp), cstate,
+					    &fallocate->falloc_stateid,
+					    WR_STATE, &file);
+	if (status != nfs_ok) {
+		dprintk("NFSD: nfsd4_fallocate: couldn't process stateid!\n");
+		return status;
+	}
+
+	status = nfsd4_vfs_fallocate(rqstp, &cstate->current_fh, file,
+				     fallocate->falloc_offset,
+				     fallocate->falloc_length,
+				     flags);
+	fput(file);
+	return status;
+}
+
+static __be32
+nfsd4_allocate(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	       struct nfsd4_fallocate *fallocate)
+{
+	return nfsd4_fallocate(rqstp, cstate, fallocate, 0);
+}
+
+static __be32
 nfsd4_seek(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		struct nfsd4_seek *seek)
 {
@@ -1929,6 +1959,12 @@ static struct nfsd4_operation nfsd4_ops[] = {
 	},
 
 	/* NFSv4.2 operations */
+	[OP_ALLOCATE] = {
+		.op_func = (nfsd4op_func)nfsd4_allocate,
+		.op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
+		.op_name = "OP_ALLOCATE",
+		.op_rsize_bop = (nfsd4op_rsize)nfsd4_write_rsize,
+	},
 	[OP_SEEK] = {
 		.op_func = (nfsd4op_func)nfsd4_seek,
 		.op_name = "OP_SEEK",
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index eeea7a9..a60cff8 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1514,6 +1514,23 @@ static __be32 nfsd4_decode_reclaim_complete(struct nfsd4_compoundargs *argp, str
 }
 
 static __be32
+nfsd4_decode_fallocate(struct nfsd4_compoundargs *argp,
+		       struct nfsd4_fallocate *fallocate)
+{
+	DECODE_HEAD;
+
+	status = nfsd4_decode_stateid(argp, &fallocate->falloc_stateid);
+	if (status)
+		return status;
+
+	READ_BUF(16);
+	p = xdr_decode_hyper(p, &fallocate->falloc_offset);
+	xdr_decode_hyper(p, &fallocate->falloc_length);
+
+	DECODE_TAIL;
+}
+
+static __be32
 nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek)
 {
 	DECODE_HEAD;
@@ -1604,7 +1621,7 @@ static nfsd4_dec nfsd4_dec_ops[] = {
 	[OP_RECLAIM_COMPLETE]	= (nfsd4_dec)nfsd4_decode_reclaim_complete,
 
 	/* new operations for NFSv4.2 */
-	[OP_ALLOCATE]		= (nfsd4_dec)nfsd4_decode_notsupp,
+	[OP_ALLOCATE]		= (nfsd4_dec)nfsd4_decode_fallocate,
 	[OP_COPY]		= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_COPY_NOTIFY]	= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_DEALLOCATE]		= (nfsd4_dec)nfsd4_decode_notsupp,
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 989129e..2157e79 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -16,6 +16,7 @@
 #include <linux/fs.h>
 #include <linux/file.h>
 #include <linux/splice.h>
+#include <linux/falloc.h>
 #include <linux/fcntl.h>
 #include <linux/namei.h>
 #include <linux/delay.h>
@@ -533,6 +534,28 @@ __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
 }
 #endif
 
+__be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
+			   struct file *file, loff_t offset, loff_t len,
+			   int flags)
+{
+	__be32 err;
+	int error;
+
+	if (!S_ISREG(file_inode(file)->i_mode))
+		return nfserr_inval;
+
+	err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry, NFSD_MAY_WRITE);
+	if (err)
+		return err;
+
+	error = vfs_fallocate(file, flags, offset, len);
+	if (!error)
+		error = commit_metadata(fhp);
+
+	if (error == -ENODEV)
+		return nfserr_inval;
+	return nfserrno(error);
+}
 #endif /* defined(CONFIG_NFSD_V4) */
 
 #ifdef CONFIG_NFSD_V3
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index c2ff3f1..7ffdb14 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -54,6 +54,8 @@ int nfsd_mountpoint(struct dentry *, struct svc_export *);
 #ifdef CONFIG_NFSD_V4
 __be32          nfsd4_set_nfs4_label(struct svc_rqst *, struct svc_fh *,
 		    struct xdr_netobj *);
+__be32		nfsd4_vfs_fallocate(struct svc_rqst *, struct svc_fh *,
+				    struct file *, loff_t, loff_t, int);
 #endif /* CONFIG_NFSD_V4 */
 __be32		nfsd_create(struct svc_rqst *, struct svc_fh *,
 				char *name, int len, struct iattr *attrs,
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 5720e94..eeaa0d0 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -428,6 +428,13 @@ struct nfsd4_reclaim_complete {
 	u32 rca_one_fs;
 };
 
+struct nfsd4_fallocate {
+	/* request */
+	stateid_t	falloc_stateid;
+	loff_t		falloc_offset;
+	u64		falloc_length;
+};
+
 struct nfsd4_seek {
 	/* request */
 	stateid_t	seek_stateid;
@@ -486,6 +493,7 @@ struct nfsd4_op {
 		struct nfsd4_free_stateid	free_stateid;
 
 		/* NFSv4.2 */
+		struct nfsd4_fallocate		allocate;
 		struct nfsd4_seek		seek;
 	} u;
 	struct nfs4_replay *			replay;
