nfs: Add DEALLOCATE support

This patch adds support for using the NFS v4.2 operation DEALLOCATE to
punch holes in a file.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs42.h

@@ -7,6 +7,7 @@
 
 /* nfs4.2proc.c */
 int nfs42_proc_allocate(struct file *, loff_t, loff_t);
+int nfs42_proc_deallocate(struct file *, loff_t, loff_t);
 loff_t nfs42_proc_llseek(struct file *, loff_t, int);
 
 /* nfs4.2xdr.h */

fs/nfs/nfs42proc.c

@@ -90,6 +90,23 @@ int nfs42_proc_allocate(struct file *filep, loff_t offset, loff_t len)
 	return err;
 }
 
+int nfs42_proc_deallocate(struct file *filep, loff_t offset, loff_t len)
+{
+	struct rpc_message msg = {
+		.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_DEALLOCATE],
+	};
+	struct inode *inode = file_inode(filep);
+	int err;
+
+	if (!nfs_server_capable(inode, NFS_CAP_DEALLOCATE))
+		return -EOPNOTSUPP;
+
+	err = nfs42_proc_fallocate(&msg, filep, offset, len);
+	if (err == -EOPNOTSUPP)
+		NFS_SERVER(inode)->caps &= ~NFS_CAP_DEALLOCATE;
+	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

@@ -10,6 +10,9 @@
 #define encode_allocate_maxsz		(op_encode_hdr_maxsz + \
 					 encode_fallocate_maxsz)
 #define decode_allocate_maxsz		(op_decode_hdr_maxsz)
+#define encode_deallocate_maxsz		(op_encode_hdr_maxsz + \
+					 encode_fallocate_maxsz)
+#define decode_deallocate_maxsz		(op_decode_hdr_maxsz)
 #define encode_seek_maxsz		(op_encode_hdr_maxsz + \
 					 encode_stateid_maxsz + \
 					 2 /* offset */ + \
@@ -26,6 +29,12 @@
 #define NFS4_dec_allocate_sz		(compound_decode_hdr_maxsz + \
 					 decode_putfh_maxsz + \
 					 decode_allocate_maxsz)
+#define NFS4_enc_deallocate_sz		(compound_encode_hdr_maxsz + \
+					 encode_putfh_maxsz + \
+					 encode_deallocate_maxsz)
+#define NFS4_dec_deallocate_sz		(compound_decode_hdr_maxsz + \
+					 decode_putfh_maxsz + \
+					 decode_deallocate_maxsz)
 #define NFS4_enc_seek_sz		(compound_encode_hdr_maxsz + \
 					 encode_putfh_maxsz + \
 					 encode_seek_maxsz)
@@ -50,6 +59,14 @@ static void encode_allocate(struct xdr_stream *xdr,
 	encode_fallocate(xdr, args);
 }
 
+static void encode_deallocate(struct xdr_stream *xdr,
+			      struct nfs42_falloc_args *args,
+			      struct compound_hdr *hdr)
+{
+	encode_op_hdr(xdr, OP_DEALLOCATE, decode_deallocate_maxsz, hdr);
+	encode_fallocate(xdr, args);
+}
+
 static void encode_seek(struct xdr_stream *xdr,
 			struct nfs42_seek_args *args,
 			struct compound_hdr *hdr)
@@ -78,6 +95,24 @@ static void nfs4_xdr_enc_allocate(struct rpc_rqst *req,
 	encode_nops(&hdr);
 }
 
+/*
+ * Encode DEALLOCATE request
+ */
+static void nfs4_xdr_enc_deallocate(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_deallocate(xdr, args, &hdr);
+	encode_nops(&hdr);
+}
+
 /*
  * Encode SEEK request
  */
@@ -101,6 +136,11 @@ static int decode_allocate(struct xdr_stream *xdr, struct nfs42_falloc_res *res)
 	return decode_op_hdr(xdr, OP_ALLOCATE);
 }
 
+static int decode_deallocate(struct xdr_stream *xdr, struct nfs42_falloc_res *res)
+{
+	return decode_op_hdr(xdr, OP_DEALLOCATE);
+}
+
 static int decode_seek(struct xdr_stream *xdr, struct nfs42_seek_res *res)
 {
 	int status;
@@ -147,6 +187,30 @@ static int nfs4_xdr_dec_allocate(struct rpc_rqst *rqstp,
 	return status;
 }
 
+/*
+ * Decode DEALLOCATE request
+ */
+static int nfs4_xdr_dec_deallocate(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_deallocate(xdr, res);
+out:
+	return status;
+}
+
 /*
  * Decode SEEK request
  */

fs/nfs/nfs4file.c

@@ -145,7 +145,7 @@ static long nfs42_fallocate(struct file *filep, int mode, loff_t offset, loff_t
 	if (!S_ISREG(inode->i_mode))
 		return -EOPNOTSUPP;
 
-	if (mode != 0)
+	if ((mode != 0) && (mode != (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE)))
 		return -EOPNOTSUPP;
 
 	ret = inode_newsize_ok(inode, offset + len);
@@ -153,7 +153,10 @@ static long nfs42_fallocate(struct file *filep, int mode, loff_t offset, loff_t
 		return ret;
 
 	mutex_lock(&inode->i_mutex);
-	ret = nfs42_proc_allocate(filep, offset, len);
+	if (mode & FALLOC_FL_PUNCH_HOLE)
+		ret = nfs42_proc_deallocate(filep, offset, len);
+	else
+		ret = nfs42_proc_allocate(filep, offset, len);
 	mutex_unlock(&inode->i_mutex);
 
 	nfs_zap_caches(inode);

fs/nfs/nfs4proc.c

@@ -8425,6 +8425,7 @@ static const struct nfs4_minor_version_ops nfs_v4_2_minor_ops = {
 		| NFS_CAP_STATEID_NFSV41
 		| NFS_CAP_ATOMIC_OPEN_V1
 		| NFS_CAP_ALLOCATE
+		| NFS_CAP_DEALLOCATE
 		| NFS_CAP_SEEK,
 	.init_client = nfs41_init_client,
 	.shutdown_client = nfs41_shutdown_client,

fs/nfs/nfs4xdr.c

@@ -7395,6 +7395,7 @@ struct rpc_procinfo	nfs4_procedures[] = {
 #ifdef CONFIG_NFS_V4_2
 	PROC(SEEK,		enc_seek,		dec_seek),
 	PROC(ALLOCATE,		enc_allocate,		dec_allocate),
+	PROC(DEALLOCATE,	enc_deallocate,		dec_deallocate),
 #endif /* CONFIG_NFS_V4_2 */
 };
 

include/linux/nfs4.h

@@ -491,6 +491,7 @@ enum {
 	/* nfs42 */
 	NFSPROC4_CLNT_SEEK,
 	NFSPROC4_CLNT_ALLOCATE,
+	NFSPROC4_CLNT_DEALLOCATE,
 };
 
 /* nfs41 types */

include/linux/nfs_fs_sb.h

@@ -232,5 +232,6 @@ struct nfs_server {
 #define NFS_CAP_SECURITY_LABEL	(1U << 18)
 #define NFS_CAP_SEEK		(1U << 19)
 #define NFS_CAP_ALLOCATE	(1U << 20)
+#define NFS_CAP_DEALLOCATE	(1U << 21)
 
 #endif