On Thursday 09 January 2020 13:44:05 Jan Kara wrote:
> On Wed 08-01-20 23:32:40, Pali Rohár wrote:
> > On Wednesday 08 January 2020 13:19:19 Jan Kara wrote:
> > > Free space on filesystems with metadata or virtual partition maps
> > > currently gets misreported. This is because these partitions are just
> > > remapped onto underlying real partitions from which keep track of free
> > > blocks. Take this remapping into account when counting free blocks as
> > > well.
> > >
> > > Reported-by: Pali Rohár <pali.rohar@xxxxxxxxx>
> > > Signed-off-by: Jan Kara <jack@xxxxxxx>
> > > ---
> > > fs/udf/super.c | 19 ++++++++++++++-----
> > > 1 file changed, 14 insertions(+), 5 deletions(-)
> > >
> > > I plan to take this patch to my tree.
> > >
> > > diff --git a/fs/udf/super.c b/fs/udf/super.c
> > > index 8c28e93e9b73..b89e420a4b85 100644
> > > --- a/fs/udf/super.c
> > > +++ b/fs/udf/super.c
> > > @@ -2492,17 +2492,26 @@ static unsigned int udf_count_free_table(struct super_block *sb,
> > > static unsigned int udf_count_free(struct super_block *sb)
> > > {
> > > unsigned int accum = 0;
> > > - struct udf_sb_info *sbi;
> > > + struct udf_sb_info *sbi = UDF_SB(sb);
> > > struct udf_part_map *map;
> > > + unsigned int part = sbi->s_partition;
> > > + int ptype = sbi->s_partmaps[part].s_partition_type;
> > > +
> > > + if (ptype == UDF_METADATA_MAP25) {
> > > + part = sbi->s_partmaps[part].s_type_specific.s_metadata.
> > > + s_phys_partition_ref;
> > > + } else if (ptype == UDF_VIRTUAL_MAP15 || ptype == UDF_VIRTUAL_MAP20) {
> > > + part = UDF_I(sbi->s_vat_inode)->i_location.
> > > + partitionReferenceNum;
> >
> > Hello! I do not think that it make sense to report "free blocks" for
> > discs with Virtual partition. By definition of VAT, all blocks prior to
> > VAT are already "read-only" and therefore these blocks cannot be use for
> > writing new data by any implementation. And because VAT is stored on the
> > last block, in our model all blocks are "occupied".
>
> Fair enough. Let's just always return 0 for disks with VAT partition.
>
> > > + }
> > >
> > > - sbi = UDF_SB(sb);
> > > if (sbi->s_lvid_bh) {
> > > struct logicalVolIntegrityDesc *lvid =
> > > (struct logicalVolIntegrityDesc *)
> > > sbi->s_lvid_bh->b_data;
> > > - if (le32_to_cpu(lvid->numOfPartitions) > sbi->s_partition) {
> > > + if (le32_to_cpu(lvid->numOfPartitions) > part) {
> > > accum = le32_to_cpu(
> > > - lvid->freeSpaceTable[sbi->s_partition]);
> > > + lvid->freeSpaceTable[part]);
> >
> > And in any case freeSpaceTable should not be used for discs with VAT.
> > And we should ignore its value for discs with VAT.
> >
> > UDF 2.60 2.2.6.2: Free Space Table values be maintained ... except ...
> > for a virtual partition ...
> >
> > And same applies for "partition with Access Type pseudo-overwritable".
>
> Well this is handled by the 'accum == 0xffffffff' condition below. So we
> effectively ignore these values.
Ok.
> > > if (accum == 0xFFFFFFFF)
> > > accum = 0;
> > > }
>
> Honza
--
Pali Rohár
pali.rohar@xxxxxxxxx
