On Thu, Apr 01, 2021 at 01:44:10AM +0000, Al Viro wrote: > On Wed, Mar 31, 2021 at 06:08:52PM -0700, Darrick J. Wong wrote: > > > + ret = vfs_xchg_file_range(file1.file, file2, &args); > > + if (ret) > > + goto fdput; > > + > > + /* > > + * The VFS will set RANGE_FSYNC on its own if the file or inode require > > + * synchronous writes. Don't leak this back to userspace. > > + */ > > + args.flags &= ~FILE_XCHG_RANGE_FSYNC; > > + args.flags |= (old_flags & FILE_XCHG_RANGE_FSYNC); > > + > > + if (copy_to_user(argp, &args, sizeof(args))) > > + ret = -EFAULT; > > Erm... How is userland supposed to figure out whether that EFAULT > came before or after the operation? Which of the fields are outputs, > anyway? Come to think of it, none of the fields are outputs, so this whole block can go away. Thanks for noticing that. :) > > + /* Don't touch certain kinds of inodes */ > > + if (IS_IMMUTABLE(inode1) || IS_IMMUTABLE(inode2)) > > + return -EPERM; > > Append-only should get the same treatment (and IMO if you have Assuming you meant IS_APPEND, I thought we only checked that at open time, as part of requiring O_APPEND? > O_APPEND on either file, you should get a failure as well). generic_rw_checks (which is called by do_xchg_file_range) will send back -EBADF if the file descriptors are O_APPEND. --D
