Chao, got it on f2fs_is_compress_algorithm_valid().
I also agree on Eric's opinion on that error value.
2020년 10월 30일 (금) 오전 12:54, Eric Biggers <ebigg...@kernel.org>님이 작성:
>
> On Thu, Oct 29, 2020 at 03:29:17PM +0800, Chao Yu wrote:
> > > +static int f2fs_ioc_set_compress_option(struct file *filp, unsigned long
> > > arg)
> > > +{
> > > + struct inode *inode = file_inode(filp);
> > > + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> > > + struct f2fs_comp_option option;
> > > + int ret = 0;
> > > +
> > > + if (!f2fs_sb_has_compression(sbi))
> > > + return -EOPNOTSUPP;
> > > +
> > > + if (!(filp->f_mode & FMODE_WRITE))
> > > + return -EBADF;
> > > +
> > > + if (copy_from_user(&option, (struct f2fs_comp_option __user *)arg,
> > > + sizeof(option)))
> > > + return -EFAULT;
> > > +
> > > + if (!f2fs_compressed_file(inode) ||
> > > + option.log_cluster_size < MIN_COMPRESS_LOG_SIZE ||
> > > + option.log_cluster_size > MAX_COMPRESS_LOG_SIZE ||
> > > + option.algorithm >= COMPRESS_MAX)
> > > + return -EINVAL;
> > > +
> > > + file_start_write(filp);
> > > + inode_lock(inode);
> > > +
> > > + if (f2fs_is_mmap_file(inode) || get_dirty_pages(inode)) {
> > > + ret = -EBUSY;
> > > + goto out;
> > > + }
> > > +
> > > + if (inode->i_size != 0) {
> > > + ret = -EFBIG;
> > > + goto out;
> > > + }
> >
> > Hmm...
> >
> > Shouldn't it be:
> >
> > if (algorithm >= COMPRESS_MAX) {
> > ret = -ENOPKG;
> > goto out;
> > }
> >
> > if (!f2fs_cops[algorithm])
> > f2fs_warn(...);
>
> Note that my intent with recommending ENOPKG was for it to be returned in the
> !f2fs_cops[algorithm] case, similar to how opening an encrypted file when the
> encryption algorithm is recognized but not supported by the kernel returns
> ENOPKG. For a truly unrecognized algorithm (algorithm >= COMPRESS_MAX),
> EINVAL
> would probably be more appropriate. So if !f2fs_cops[algorithm] is now
> allowed,
> then ENOPKG should no longer be among the error codes this ioctl returns.
>
> - Eric
