Re: [PATCH v3 6/7] btrfs-progs: check: update inline extent length checking

On Wed, 8 Jul 2026 at 00:43, Qu Wenruo <[email protected]> wrote:
> =E5=9C=A8 2026/7/7 23:57, Daniel Vacek =E5=86=99=E9=81=93:
> > From: Sweet Tea Dorminy <[email protected]>
> >
> > As part of the encryption changes, encrypted inline file extents record
> > their actual data length in ram_bytes, like compressed inline file
> > extents, while the item's length records the actual size. As such,
> > encrypted inline extents must be treated like compressed ones for
> > inode length consistency checking.
> >
> > Signed-off-by: Sweet Tea Dorminy <[email protected]>
> > Signed-off-by: Daniel Vacek <[email protected]>
> > ---
> >   check/main.c | 31 +++++++++++++++++--------------
> >   1 file changed, 17 insertions(+), 14 deletions(-)
> >
> > diff --git a/check/main.c b/check/main.c
> > index 9447b01e..cadcfef0 100644
> > --- a/check/main.c
> > +++ b/check/main.c
> > @@ -1720,9 +1720,7 @@ static int process_file_extent(struct btrfs_root =
*root,
> >       u64 disk_bytenr =3D 0;
> >       u64 extent_offset =3D 0;
> >       u64 mask =3D gfs_info->sectorsize - 1;
> > -     u32 max_inline_size =3D min_t(u32, mask,
> > -                             BTRFS_MAX_INLINE_DATA_SIZE(gfs_info));
> > -     u8 compression;
> > +     u8 compression, encryption;
> >       int extent_type;
> >       int ret;
> >
> > @@ -1747,25 +1745,30 @@ static int process_file_extent(struct btrfs_roo=
t *root,
> >       fi =3D btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
> >       extent_type =3D btrfs_file_extent_type(eb, fi);
> >       compression =3D btrfs_file_extent_compression(eb, fi);
> > +     encryption  =3D btrfs_file_extent_encryption(eb, fi);
> >
> >       if (extent_type =3D=3D BTRFS_FILE_EXTENT_INLINE) {
> > -             num_bytes =3D btrfs_file_extent_ram_bytes(eb, fi);
> > -             if (num_bytes =3D=3D 0)
> > +             u32 max_inline_size =3D min_t(u32, mask,
> > +                                     BTRFS_MAX_INLINE_DATA_SIZE(gfs_in=
fo));
> > +             u64 num_disk_bytes =3D btrfs_file_extent_inline_item_len(=
eb, slot);
> > +             u64 num_decoded_bytes =3D btrfs_file_extent_ram_bytes(eb,=
 fi);
> > +             if (num_decoded_bytes =3D=3D 0)
> >                       rec->errors |=3D I_ERR_BAD_FILE_EXTENT;
> > -             if (compression) {
> > -                     if (btrfs_file_extent_inline_item_len(eb, slot) >
> > -                         max_inline_size ||
> > -                         num_bytes > gfs_info->sectorsize)
> > +             if (compression || encryption) {
> > +                     if (encryption)
> > +                             max_inline_size =3D min_t(u32, gfs_info->=
sectorsize,
> > +                                     BTRFS_MAX_INLINE_DATA_SIZE(gfs_in=
fo));
>
> The change looks good to me now.
>
> However I'm just curious, is it possible to limit the encrypted data
> size to sectorsize-1?
>
> Or it is some fscrypt limit internal requiring a power-of-2 size or just
> lack of interface?

The encrypted data has the granularity of the cipher block size. With
AES, it's 16 bytes. Hence why.
Eventually the best we could do would be sectorsize-16. But then, if
the cipher changed in the future...

--nX

> Anyway I won't object this new change.
>
> Thanks,
> Qu
>
> > +                     if (num_disk_bytes > max_inline_size ||
> > +                         num_decoded_bytes > gfs_info->sectorsize)
> >                               rec->errors |=3D I_ERR_FILE_EXTENT_TOO_LA=
RGE;
> >               } else {
> > -                     if (num_bytes > max_inline_size)
> > +                     if (num_decoded_bytes > max_inline_size)
> >                               rec->errors |=3D I_ERR_FILE_EXTENT_TOO_LA=
RGE;
> > -                     if (btrfs_file_extent_inline_item_len(eb, slot) !=
=3D
> > -                         num_bytes)
> > +                     if (num_disk_bytes !=3D num_decoded_bytes)
> >                               rec->errors |=3D I_ERR_INLINE_RAM_BYTES_W=
RONG;
> >               }
> > -             rec->found_size +=3D num_bytes;
> > -             num_bytes =3D (num_bytes + mask) & ~mask;
> > +             rec->found_size +=3D num_decoded_bytes;
> > +             num_bytes =3D (num_decoded_bytes + mask) & ~mask;
> >       } else if (extent_type =3D=3D BTRFS_FILE_EXTENT_REG ||
> >                  extent_type =3D=3D BTRFS_FILE_EXTENT_PREALLOC) {
> >               num_bytes =3D btrfs_file_extent_num_bytes(eb, fi);
>