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 <20201022042608.GB857@sol.localdomain>
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From:   Daeho Jeong <daeho43@gmail.com>
Date:   Thu, 22 Oct 2020 13:36:58 +0900
Message-ID: <CACOAw_y1Njm0zswqFXS4EXWcetYAvCGgHpQPqYqaRKh=+JmU8Q@mail.gmail.com>
Subject: Re: [f2fs-dev] [PATCH v2 2/2] f2fs: add F2FS_IOC_SET_COMPRESS_OPTION ioctl
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com,
        Daeho Jeong <daehojeong@google.com>
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> The use of ?: here is a bit strange.  How about:
>
>         return algorithm < COMPRESS_MAX && f2fs_cops[algorithm] !=3D NULL=
;
>

Ack

> Likewise, EINVAL tends to be over-used, which makes it ambiguous.  Maybe =
use
> ENOPKG for the case where algorithm < COMPRESS_MAX but the algorithm wasn=
't
> compiled into the kernel?  That would be similar to how opening an encryp=
ted
> file fails with ENOPKG when the encryption algorithm isn't available.

Ack

> How about EBUSY for f2fs_is_mmap_file(inode) || get_dirty_pages(inode),
> and EFBIG for inode->i_size !=3D 0?

Ack

Thanks~!

2020=EB=85=84 10=EC=9B=94 22=EC=9D=BC (=EB=AA=A9) =EC=98=A4=ED=9B=84 1:26, =
Eric Biggers <ebiggers@kernel.org>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
> On Thu, Oct 22, 2020 at 12:58:48PM +0900, Daeho Jeong wrote:
> > diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
> > index 7895186cc765..3b58a41223f8 100644
> > --- a/fs/f2fs/compress.c
> > +++ b/fs/f2fs/compress.c
> > @@ -514,6 +514,11 @@ bool f2fs_is_compress_backend_ready(struct inode *=
inode)
> >       return f2fs_cops[F2FS_I(inode)->i_compress_algorithm];
> >  }
> >
> > +bool f2fs_is_compress_algorithm_ready(unsigned char algorithm)
> > +{
> > +     return algorithm >=3D COMPRESS_MAX ? false : f2fs_cops[algorithm]=
;
> > +}
>
> The use of ?: here is a bit strange.  How about:
>
>         return algorithm < COMPRESS_MAX && f2fs_cops[algorithm] !=3D NULL=
;
>
> > +     if (option.log_cluster_size < MIN_COMPRESS_LOG_SIZE ||
> > +                     option.log_cluster_size > MAX_COMPRESS_LOG_SIZE |=
|
> > +                     !f2fs_is_compress_algorithm_ready(option.algorith=
m))
> > +             return -EINVAL;
>
> Likewise, EINVAL tends to be over-used, which makes it ambiguous.  Maybe =
use
> ENOPKG for the case where algorithm < COMPRESS_MAX but the algorithm wasn=
't
> compiled into the kernel?  That would be similar to how opening an encryp=
ted
> file fails with ENOPKG when the encryption algorithm isn't available.
>
> > +     if (f2fs_is_mmap_file(inode) ||
> > +                     get_dirty_pages(inode) || inode->i_size) {
> > +             ret =3D -EINVAL;
> > +             goto out;
> > +     }
>
> How about EBUSY for f2fs_is_mmap_file(inode) || get_dirty_pages(inode),
> and EFBIG for inode->i_size !=3D 0?
>
> - Eric