nfs: Add ALLOCATE support

This patch adds support for using the NFS v4.2 operation ALLOCATE to
preallocate data in a file.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/inode.c

@@ -192,6 +192,7 @@ void nfs_zap_caches(struct inode *inode)
 	nfs_zap_caches_locked(inode);
 	spin_unlock(&inode->i_lock);
 }
+EXPORT_SYMBOL_GPL(nfs_zap_caches);
 
 void nfs_zap_mapping(struct inode *inode, struct address_space *mapping)
 {

fs/nfs/nfs42.h

@@ -6,6 +6,7 @@
 #define __LINUX_FS_NFS_NFS4_2_H
 
 /* nfs4.2proc.c */
+int nfs42_proc_allocate(struct file *, loff_t, loff_t);
 loff_t nfs42_proc_llseek(struct file *, loff_t, int);
 
 /* nfs4.2xdr.h */

fs/nfs/nfs42proc.c

@@ -32,6 +32,64 @@ static int nfs42_set_rw_stateid(nfs4_stateid *dst, struct file *file,
 	return ret;
 }
 
+static int _nfs42_proc_fallocate(struct rpc_message *msg, struct file *filep,
+				 loff_t offset, loff_t len)
+{
+	struct inode *inode = file_inode(filep);
+	struct nfs42_falloc_args args = {
+		.falloc_fh	= NFS_FH(inode),
+		.falloc_offset	= offset,
+		.falloc_length	= len,
+	};
+	struct nfs42_falloc_res res;
+	struct nfs_server *server = NFS_SERVER(inode);
+	int status;
+
+	msg->rpc_argp = &args;
+	msg->rpc_resp = &res;
+
+	status = nfs42_set_rw_stateid(&args.falloc_stateid, filep, FMODE_WRITE);
+	if (status)
+		return status;
+
+	return nfs4_call_sync(server->client, server, msg,
+			      &args.seq_args, &res.seq_res, 0);
+}
+
+static int nfs42_proc_fallocate(struct rpc_message *msg, struct file *filep,
+				loff_t offset, loff_t len)
+{
+	struct nfs_server *server = NFS_SERVER(file_inode(filep));
+	struct nfs4_exception exception = { };
+	int err;
+
+	do {
+		err = _nfs42_proc_fallocate(msg, filep, offset, len);
+		if (err == -ENOTSUPP)
+			return -EOPNOTSUPP;
+		err = nfs4_handle_exception(server, err, &exception);
+	} while (exception.retry);
+
+	return err;
+}
+
+int nfs42_proc_allocate(struct file *filep, loff_t offset, loff_t len)
+{
+	struct rpc_message msg = {
+		.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_ALLOCATE],
+	};
+	struct inode *inode = file_inode(filep);
+	int err;
+
+	if (!nfs_server_capable(inode, NFS_CAP_ALLOCATE))
+		return -EOPNOTSUPP;
+
+	err = nfs42_proc_fallocate(&msg, filep, offset, len);
+	if (err == -EOPNOTSUPP)
+		NFS_SERVER(inode)->caps &= ~NFS_CAP_ALLOCATE;
+	return err;
+}
+
 loff_t nfs42_proc_llseek(struct file *filep, loff_t offset, int whence)
 {
 	struct inode *inode = file_inode(filep);

fs/nfs/nfs42xdr.c

@@ -4,6 +4,12 @@
 #ifndef __LINUX_FS_NFS_NFS4_2XDR_H
 #define __LINUX_FS_NFS_NFS4_2XDR_H
 
+#define encode_fallocate_maxsz		(encode_stateid_maxsz + \
+					 2 /* offset */ + \
+					 2 /* length */)
+#define encode_allocate_maxsz		(op_encode_hdr_maxsz + \
+					 encode_fallocate_maxsz)
+#define decode_allocate_maxsz		(op_decode_hdr_maxsz)
 #define encode_seek_maxsz		(op_encode_hdr_maxsz + \
 					 encode_stateid_maxsz + \
 					 2 /* offset */ + \
@@ -14,6 +20,12 @@
 					 2 /* offset */ + \
 					 2 /* length */)
 
+#define NFS4_enc_allocate_sz		(compound_encode_hdr_maxsz + \
+					 encode_putfh_maxsz + \
+					 encode_allocate_maxsz)
+#define NFS4_dec_allocate_sz		(compound_decode_hdr_maxsz + \
+					 decode_putfh_maxsz + \
+					 decode_allocate_maxsz)
 #define NFS4_enc_seek_sz		(compound_encode_hdr_maxsz + \
 					 encode_putfh_maxsz + \
 					 encode_seek_maxsz)
@@ -22,6 +34,22 @@
 					 decode_seek_maxsz)
 
 
+static void encode_fallocate(struct xdr_stream *xdr,
+			     struct nfs42_falloc_args *args)
+{
+	encode_nfs4_stateid(xdr, &args->falloc_stateid);
+	encode_uint64(xdr, args->falloc_offset);
+	encode_uint64(xdr, args->falloc_length);
+}
+
+static void encode_allocate(struct xdr_stream *xdr,
+			    struct nfs42_falloc_args *args,
+			    struct compound_hdr *hdr)
+{
+	encode_op_hdr(xdr, OP_ALLOCATE, decode_allocate_maxsz, hdr);
+	encode_fallocate(xdr, args);
+}
+
 static void encode_seek(struct xdr_stream *xdr,
 			struct nfs42_seek_args *args,
 			struct compound_hdr *hdr)
@@ -32,6 +60,24 @@ static void encode_seek(struct xdr_stream *xdr,
 	encode_uint32(xdr, args->sa_what);
 }
 
+/*
+ * Encode ALLOCATE request
+ */
+static void nfs4_xdr_enc_allocate(struct rpc_rqst *req,
+				  struct xdr_stream *xdr,
+				  struct nfs42_falloc_args *args)
+{
+	struct compound_hdr hdr = {
+		.minorversion = nfs4_xdr_minorversion(&args->seq_args),
+	};
+
+	encode_compound_hdr(xdr, req, &hdr);
+	encode_sequence(xdr, &args->seq_args, &hdr);
+	encode_putfh(xdr, args->falloc_fh, &hdr);
+	encode_allocate(xdr, args, &hdr);
+	encode_nops(&hdr);
+}
+
 /*
  * Encode SEEK request
  */
@@ -50,6 +96,11 @@ static void nfs4_xdr_enc_seek(struct rpc_rqst *req,
 	encode_nops(&hdr);
 }
 
+static int decode_allocate(struct xdr_stream *xdr, struct nfs42_falloc_res *res)
+{
+	return decode_op_hdr(xdr, OP_ALLOCATE);
+}
+
 static int decode_seek(struct xdr_stream *xdr, struct nfs42_seek_res *res)
 {
 	int status;
@@ -72,6 +123,30 @@ static int decode_seek(struct xdr_stream *xdr, struct nfs42_seek_res *res)
 	return -EIO;
 }
 
+/*
+ * Decode ALLOCATE request
+ */
+static int nfs4_xdr_dec_allocate(struct rpc_rqst *rqstp,
+				 struct xdr_stream *xdr,
+				 struct nfs42_falloc_res *res)
+{
+	struct compound_hdr hdr;
+	int status;
+
+	status = decode_compound_hdr(xdr, &hdr);
+	if (status)
+		goto out;
+	status = decode_sequence(xdr, &res->seq_res, rqstp);
+	if (status)
+		goto out;
+	status = decode_putfh(xdr);
+	if (status)
+		goto out;
+	status = decode_allocate(xdr, res);
+out:
+	return status;
+}
+
 /*
  * Decode SEEK request
  */

fs/nfs/nfs4_fs.h

@@ -226,6 +226,7 @@ int nfs4_replace_transport(struct nfs_server *server,
 				const struct nfs4_fs_locations *locations);
 
 /* nfs4proc.c */
+extern int nfs4_handle_exception(struct nfs_server *, int, struct nfs4_exception *);
 extern int nfs4_call_sync(struct rpc_clnt *, struct nfs_server *,
 			  struct rpc_message *, struct nfs4_sequence_args *,
 			  struct nfs4_sequence_res *, int);

fs/nfs/nfs4file.c

@@ -3,6 +3,8 @@
  *
  *  Copyright (C) 1992  Rick Sladkey
  */
+#include <linux/fs.h>
+#include <linux/falloc.h>
 #include <linux/nfs_fs.h>
 #include "internal.h"
 #include "fscache.h"
@@ -134,6 +136,29 @@ static loff_t nfs4_file_llseek(struct file *filep, loff_t offset, int whence)
 		return nfs_file_llseek(filep, offset, whence);
 	}
 }
+
+static long nfs42_fallocate(struct file *filep, int mode, loff_t offset, loff_t len)
+{
+	struct inode *inode = file_inode(filep);
+	long ret;
+
+	if (!S_ISREG(inode->i_mode))
+		return -EOPNOTSUPP;
+
+	if (mode != 0)
+		return -EOPNOTSUPP;
+
+	ret = inode_newsize_ok(inode, offset + len);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&inode->i_mutex);
+	ret = nfs42_proc_allocate(filep, offset, len);
+	mutex_unlock(&inode->i_mutex);
+
+	nfs_zap_caches(inode);
+	return ret;
+}
 #endif /* CONFIG_NFS_V4_2 */
 
 const struct file_operations nfs4_file_operations = {
@@ -155,6 +180,9 @@ const struct file_operations nfs4_file_operations = {
 	.flock		= nfs_flock,
 	.splice_read	= nfs_file_splice_read,
 	.splice_write	= iter_file_splice_write,
+#ifdef CONFIG_NFS_V4_2
+	.fallocate	= nfs42_fallocate,
+#endif /* CONFIG_NFS_V4_2 */
 	.check_flags	= nfs_check_flags,
 	.setlease	= simple_nosetlease,
 };

fs/nfs/nfs4proc.c

@@ -342,7 +342,7 @@ static int nfs4_delay(struct rpc_clnt *clnt, long *timeout)
 /* This is the error handling routine for processes that are allowed
  * to sleep.
  */
-static int nfs4_handle_exception(struct nfs_server *server, int errorcode, struct nfs4_exception *exception)
+int nfs4_handle_exception(struct nfs_server *server, int errorcode, struct nfs4_exception *exception)
 {
 	struct nfs_client *clp = server->nfs_client;
 	struct nfs4_state *state = exception->state;
@@ -8424,6 +8424,7 @@ static const struct nfs4_minor_version_ops nfs_v4_2_minor_ops = {
 		| NFS_CAP_POSIX_LOCK
 		| NFS_CAP_STATEID_NFSV41
 		| NFS_CAP_ATOMIC_OPEN_V1
+		| NFS_CAP_ALLOCATE
 		| NFS_CAP_SEEK,
 	.init_client = nfs41_init_client,
 	.shutdown_client = nfs41_shutdown_client,

fs/nfs/nfs4xdr.c

@@ -7394,6 +7394,7 @@ struct rpc_procinfo	nfs4_procedures[] = {
 #endif /* CONFIG_NFS_V4_1 */
 #ifdef CONFIG_NFS_V4_2
 	PROC(SEEK,		enc_seek,		dec_seek),
+	PROC(ALLOCATE,		enc_allocate,		dec_allocate),
 #endif /* CONFIG_NFS_V4_2 */
 };
 

include/linux/nfs4.h

@@ -490,6 +490,7 @@ enum {
 
 	/* nfs42 */
 	NFSPROC4_CLNT_SEEK,
+	NFSPROC4_CLNT_ALLOCATE,
 };
 
 /* nfs41 types */

include/linux/nfs_fs_sb.h

@@ -231,5 +231,6 @@ struct nfs_server {
 #define NFS_CAP_ATOMIC_OPEN_V1	(1U << 17)
 #define NFS_CAP_SECURITY_LABEL	(1U << 18)
 #define NFS_CAP_SEEK		(1U << 19)
+#define NFS_CAP_ALLOCATE	(1U << 20)
 
 #endif

include/linux/nfs_xdr.h

@@ -1243,6 +1243,20 @@ nfs_free_pnfs_ds_cinfo(struct pnfs_ds_commit_info *cinfo)
 #endif /* CONFIG_NFS_V4_1 */
 
 #ifdef CONFIG_NFS_V4_2
+struct nfs42_falloc_args {
+	struct nfs4_sequence_args	seq_args;
+
+	struct nfs_fh			*falloc_fh;
+	nfs4_stateid			 falloc_stateid;
+	u64				 falloc_offset;
+	u64				 falloc_length;
+};
+
+struct nfs42_falloc_res {
+	struct nfs4_sequence_res	seq_res;
+	unsigned int			status;
+};
+
 struct nfs42_seek_args {
 	struct nfs4_sequence_args	seq_args;