nfs: add a helper to set NFS_ODIRECT_RESCHED_WRITES to direct writes

To allow pnfs LD to ask direct writes to be resend.
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>

fs/nfs/direct.c

@@ -116,6 +116,12 @@ static inline int put_dreq(struct nfs_direct_req *dreq)
 	return atomic_dec_and_test(&dreq->io_count);
 }
 
+void nfs_direct_set_resched_writes(struct nfs_direct_req *dreq)
+{
+	dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
+}
+EXPORT_SYMBOL_GPL(nfs_direct_set_resched_writes);
+
 static void
 nfs_direct_good_bytes(struct nfs_direct_req *dreq, struct nfs_pgio_header *hdr)
 {

fs/nfs/internal.h

@@ -502,6 +502,7 @@ static inline void nfs_inode_dio_wait(struct inode *inode)
 	inode_dio_wait(inode);
 }
 extern ssize_t nfs_dreq_bytes_left(struct nfs_direct_req *dreq);
+extern void nfs_direct_set_resched_writes(struct nfs_direct_req *dreq);
 
 /* nfs4proc.c */
 extern void __nfs4_read_done_cb(struct nfs_pgio_header *);