* can not run at the same time
                 */
                written = generic_perform_write(iocb, from);
-               if (likely(written >= 0))
-                       iocb->ki_pos = pos + written;
                ceph_end_io_write(inode);
        }
 
 
 
 out:
        inode_unlock(inode);
-       if (likely(ret > 0)) {
-               iocb->ki_pos += ret;
-               ret = generic_write_sync(iocb, ret);
-       }
-
-       return ret;
+       if (unlikely(ret <= 0))
+               return ret;
+       return generic_write_sync(iocb, ret);
 }
 
 static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
 
        ret = generic_perform_write(iocb, from);
 
        if (ret > 0) {
-               iocb->ki_pos += ret;
                f2fs_update_iostat(F2FS_I_SB(inode), inode,
                                                APP_BUFFERED_IO, ret);
        }
 
                goto out;
 
        written = result;
-       iocb->ki_pos += written;
        nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
 
        if (mntflags & NFS_MOUNT_WRITE_EAGER) {
 
                balance_dirty_pages_ratelimited(mapping);
        } while (iov_iter_count(i));
 
-       return written ? written : status;
+       if (!written)
+               return status;
+       iocb->ki_pos += written;
+       return written;
 }
 EXPORT_SYMBOL(generic_perform_write);
 
                endbyte = pos + status - 1;
                err = filemap_write_and_wait_range(mapping, pos, endbyte);
                if (err == 0) {
-                       iocb->ki_pos = endbyte + 1;
                        written += status;
                        invalidate_mapping_pages(mapping,
                                                 pos >> PAGE_SHIFT,
                }
        } else {
                written = generic_perform_write(iocb, from);
-               if (likely(written > 0))
-                       iocb->ki_pos += written;
        }
 out:
        return written ? written : err;