On Thu, 31 Mar 2022 10:42:12 -0700 Axel Rasmussen <axelrasmussen@xxxxxxxxxx> wrote: > Any strong opinions on which error code is used? I think overall I > would still pick EOPNOTSUPP, but happy to change it if anyone feels > strongly. > > - I think ENOSYS is specific to syscall nr not defined > - I think ENOTTY is specific to ioctls > - The kernel (sort of mistakenly) defines ENOTSUPP instead of ENOTSUP, > but it's marked deprecated and it's recommended to use EOPNOTSUPP > instead (despite POSIX saying these should be distinct and for > different uses). `man ftruncate' sayeth EINVAL The argument length is negative or larger than the maximum file size. which reasonably accurately describes what we're doing here? + if ((ia_valid & ATTR_SIZE) && inode->i_size) + return -EOPNOTSUPP;