Re: [PATCH 1/1] xfs_metadump: Zap more stale data

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Fri, Oct 05, 2018 at 10:46:28PM +0200, Stefan Ring wrote:
> On Fri, Oct 5, 2018 at 12:23 AM Darrick J. Wong <darrick.wong@oracle.com> wrote:
> >
> > On Thu, Oct 04, 2018 at 10:57:49PM +0200, Stefan Ring wrote:
> > > I have empirically found and tried to fix some places where stale data was not properly zeroed out.
> > >
> > > In the order of the code changes:
> > >
> > > The "freeindex" blocks in inode directories, from last entry to end of block.
> > >
> > > XFS_DIR2_LEAF1_MAGIC, from last entry to end of block.
> > >
> > > In btree format inodes before as well as after the btree pointers.
> > >
> > > In dev inodes, everything after the header.
> >
> > Mostly looks ok, but with some style issues:
> >
> > > ---
> > >  db/metadump.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++----
> > >  1 file changed, 69 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/db/metadump.c b/db/metadump.c
> > > index cc2ae9af..e7159cd1 100644
> > > --- a/db/metadump.c
> > > +++ b/db/metadump.c
> > > @@ -1421,12 +1421,42 @@ process_sf_attr(
> > >               memset(asfep, 0, XFS_DFORK_ASIZE(dip, mp) - ino_attr_size);
> > >  }
> > >
> > > +static void
> > > +process_dir_free_block(
> > > +     char                            *block)
> > > +{
> > > +     struct xfs_dir2_free            *free;
> > > +     struct xfs_dir3_icfree_hdr      freehdr;
> > > +
> > > +     if (!zero_stale_data)
> > > +             return;
> > > +
> > > +     free = (struct xfs_dir2_free *)block;
> > > +     M_DIROPS(mp)->free_hdr_from_disk(&freehdr, free);
> > > +
> > > +     /* Zero out space from end of bests[] to end of block */
> > > +     if (freehdr.magic == XFS_DIR2_FREE_MAGIC) {
> >
> > How about XFS_DIR3_FREE_MAGIC ?
> 
> Is there any documentation on DIR3? I left it out on purpose and hoped
> someone would fill in the blanks for me ;).

Fairly similar to DIR2, but with bigger headers, I think.

https://djwong.org/docs/kdoc/filesystems/xfs-data-structures/dynamic.html#leaf-directories

--D