return err;
  }
  
 -              mutex_lock(&file_inode(dst)->i_mutex);
+ static ssize_t _nfs42_proc_copy(struct file *src, loff_t pos_src,
+                               struct nfs_lock_context *src_lock,
+                               struct file *dst, loff_t pos_dst,
+                               struct nfs_lock_context *dst_lock,
+                               size_t count)
+ {
+       struct nfs42_copy_args args = {
+               .src_fh         = NFS_FH(file_inode(src)),
+               .src_pos        = pos_src,
+               .dst_fh         = NFS_FH(file_inode(dst)),
+               .dst_pos        = pos_dst,
+               .count          = count,
+       };
+       struct nfs42_copy_res res;
+       struct rpc_message msg = {
+               .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_COPY],
+               .rpc_argp = &args,
+               .rpc_resp = &res,
+       };
+       struct inode *dst_inode = file_inode(dst);
+       struct nfs_server *server = NFS_SERVER(dst_inode);
+       int status;
+ 
+       status = nfs4_set_rw_stateid(&args.src_stateid, src_lock->open_context,
+                                    src_lock, FMODE_READ);
+       if (status)
+               return status;
+ 
+       status = nfs4_set_rw_stateid(&args.dst_stateid, dst_lock->open_context,
+                                    dst_lock, FMODE_WRITE);
+       if (status)
+               return status;
+ 
+       status = nfs4_call_sync(server->client, server, &msg,
+                               &args.seq_args, &res.seq_res, 0);
+       if (status == -ENOTSUPP)
+               server->caps &= ~NFS_CAP_COPY;
+       if (status)
+               return status;
+ 
+       if (res.write_res.verifier.committed != NFS_FILE_SYNC) {
+               status = nfs_commit_file(dst, &res.write_res.verifier.verifier);
+               if (status)
+                       return status;
+       }
+ 
+       truncate_pagecache_range(dst_inode, pos_dst,
+                                pos_dst + res.write_res.count);
+ 
+       return res.write_res.count;
+ }
+ 
+ ssize_t nfs42_proc_copy(struct file *src, loff_t pos_src,
+                       struct file *dst, loff_t pos_dst,
+                       size_t count)
+ {
+       struct nfs_server *server = NFS_SERVER(file_inode(dst));
+       struct nfs_lock_context *src_lock;
+       struct nfs_lock_context *dst_lock;
+       struct nfs4_exception src_exception = { };
+       struct nfs4_exception dst_exception = { };
+       ssize_t err, err2;
+ 
+       if (!nfs_server_capable(file_inode(dst), NFS_CAP_COPY))
+               return -EOPNOTSUPP;
+ 
+       src_lock = nfs_get_lock_context(nfs_file_open_context(src));
+       if (IS_ERR(src_lock))
+               return PTR_ERR(src_lock);
+ 
+       src_exception.inode = file_inode(src);
+       src_exception.state = src_lock->open_context->state;
+ 
+       dst_lock = nfs_get_lock_context(nfs_file_open_context(dst));
+       if (IS_ERR(dst_lock)) {
+               err = PTR_ERR(dst_lock);
+               goto out_put_src_lock;
+       }
+ 
+       dst_exception.inode = file_inode(dst);
+       dst_exception.state = dst_lock->open_context->state;
+ 
+       do {
 -              mutex_unlock(&file_inode(dst)->i_mutex);
++              inode_lock(file_inode(dst));
+               err = _nfs42_proc_copy(src, pos_src, src_lock,
+                                      dst, pos_dst, dst_lock, count);
++              inode_unlock(file_inode(dst));
+ 
+               if (err == -ENOTSUPP) {
+                       err = -EOPNOTSUPP;
+                       break;
+               }
+ 
+               err2 = nfs4_handle_exception(server, err, &src_exception);
+               err  = nfs4_handle_exception(server, err, &dst_exception);
+               if (!err)
+                       err = err2;
+       } while (src_exception.retry || dst_exception.retry);
+ 
+       nfs_put_lock_context(dst_lock);
+ out_put_src_lock:
+       nfs_put_lock_context(src_lock);
+       return err;
+ }
+ 
  static loff_t _nfs42_proc_llseek(struct file *filep,
                struct nfs_lock_context *lock, loff_t offset, int whence)
  {
 
                return -ENOMEM;
        }
  
-       n = ib_map_mr_sg(mr, frmr->sg, frmr->sg_nents, NULL, PAGE_SIZE);
-       if (unlikely(n != frmr->sg_nents)) {
 -      n = ib_map_mr_sg(mr, frmr->fr_sg, frmr->fr_nents, PAGE_SIZE);
++      n = ib_map_mr_sg(mr, frmr->fr_sg, frmr->fr_nents, NULL, PAGE_SIZE);
+       if (unlikely(n != frmr->fr_nents)) {
                pr_err("RPC:       %s: failed to map mr %p (%u/%u)\n",
-                      __func__, frmr->fr_mr, n, frmr->sg_nents);
+                      __func__, frmr->fr_mr, n, frmr->fr_nents);
                rc = n < 0 ? n : -EINVAL;
                goto out_senderr;
        }