On Thu, Aug 07, 2025 at 02:24:25PM +0800, Chunsheng Luo wrote: > On Thu, Aug 07 2025, Chunsheng Luo wrote: > > > On Tue, Aug 05 2025, Miklos Szeredi wrote: > > > > + bytes_copied = fc->no_copy_file_range_64 ? > > + outarg.size : outarg_64.bytes_copied; > > + > > truncate_inode_pages_range(inode_out->i_mapping, > > ALIGN_DOWN(pos_out, PAGE_SIZE), > > - ALIGN(pos_out + outarg.size, PAGE_SIZE) - 1); > > + ALIGN(pos_out + bytes_copied, PAGE_SIZE) - 1); > > > > file_update_time(file_out); > > - fuse_write_update_attr(inode_out, pos_out + outarg.size, outarg.size); > > + fuse_write_update_attr(inode_out, pos_out + bytes_copied, bytes_copied); > > The copy_file_range syscall returns bytes_copied, a value provided by > the userspace filesystem that the kernel cannot control. If > bytes_copied > len, how should the application handle this? Similarly, > if pos_out + bytes_copied < pos_outdue to integer overflow, could this > cause any issues? Since vfs_copy_file_range->generic_copy_file_checks > already check that pos_out + len does not overflow, so just need check > bytes_copied > len. if (WARN_ON_ONCE(bytes_copied > len)) return -EIO; perhaps? --D > > Thanks > Chunsheng Luo >
