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>

1 files changed, 58 insertions, 0 deletions

diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
index 056f5aafecc1..581f34e9d8a0 100644
--- a/fs/nfs/nfs42proc.c
+++ b/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);