nfs/flexclient: export pnfs_layoutcommit_inode

flexfiles needs to start layoutcommit when necessary
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>

fs/nfs/pnfs.c

@@ -1966,6 +1966,7 @@ pnfs_layoutcommit_inode(struct inode *inode, bool sync)
 	pnfs_clear_layoutcommitting(inode);
 	goto out;
 }
+EXPORT_SYMBOL_GPL(pnfs_layoutcommit_inode);
 
 struct nfs4_threshold *pnfs_mdsthreshold_alloc(void)
 {