On Tue, Oct 23, 2018 at 5:49 PM Darrick J. Wong <darrick.wong@xxxxxxxxxx> wrote:
>
> On Thu, Oct 11, 2018 at 09:44:24PM +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_DIR{2,3}_LEAFN_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.
> > ---
> > db/metadump.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++-----
> > 1 file changed, 98 insertions(+), 8 deletions(-)
> >
> > diff --git a/db/metadump.c b/db/metadump.c
> > index ff96860d..c8213d41 100644
> > --- a/db/metadump.c
> > +++ b/db/metadump.c
> > @@ -2118,6 +2173,21 @@ process_btinode(
> > }
> >
> > pp = XFS_BMDR_PTR_ADDR(dib, 1, maxrecs);
> > +
> > + if (zero_stale_data) {
> > + char *top;
> > + int used;
> > +
> > + /* Space before btree pointers */
> > + top = (char*)XFS_BMDR_PTR_ADDR(dib, 1, nrecs);
> > + memset(top, 0, (char*)pp - top);
> > +
> > + /* Space after btree pointers */
> > + top = (char*)&pp[nrecs];
> > + used = top - (char*)dip;
> > + memset(top, 0, mp->m_sb.sb_inodesize - used);
>
> Er... this zaps everything past the end of the bmbt pointers, which
> means that this can zero the attr fork root.
True, this is broken. I'll play around a little more with this one.
