Re: debugging strategies for jffs2

[Adam Wozniak <adam.wozniak@comdev.cc>]

David Woodhouse wrote:
> 
> adam.wozniak@comdev.cc said:
> > > The interesting bit to me is that the csize is 0x0000c000
> > > and the dsize is 0x00000000.  Is this perhaps causing problems?
> >
> > At fs/jffs2/gc.c,v 1.52, line 460:
> >         fill:
> >                 ri.magic = JFFS2_MAGIC_BITMASK;
> >                 ri.nodetype = JFFS2_NODETYPE_INODE;
> >                 ri.totlen = sizeof(ri);
> >                 ri.hdr_crc = crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4);
> >                   ri.ino = inode->i_ino;
> >                 ri.version = ++f->highest_version;
> >                 ri.offset = start;
> >                 ri.csize = end - start;
> >                 ri.dsize = 0;
> >                 ri.compr = JFFS2_COMPR_ZERO;
> 
> > This seems backwards to me.  Shouldn't ri.dsize = end-start and
> > ri.csize = 0 ???
> 
> Eep, yes that would probably do it. Well spotted. That obviously wasn't one
> of my more coherent days :)
> 
> I've fixed it in v1.61 and v1.52.2.1 (on jffs2-2_4-branch) now - don't chuck
> your filesystem away though, I'll implement a workaround and ask you to test
> it.

Here's the workaround I came up with:
in scan.c:

                /* FIXME: Why do we believe totlen? */
                DIRTY_SPACE(4);
                *ofs += 4;
                return 0;
        }
 
        // TODO WOZ FIXED
 
        /* older code confused dsize and csize in some cases, fix that
here */
        if (ri.dsize == 0 && ri.compr == JFFS2_COMPR_ZERO)
        {
                ri.dsize = ri.csize;
                ri.csize = 0;
                ri.node_crc = crc32(0, &ri, sizeof(ri)-8);
        }
 
        if (ri.csize) {
                /* Check data CRC too */
                unsigned char *dbuf;
                __u32 crc;

--Adam
-- 
Adam Wozniak (KG6GZR)   COM DEV Wireless - Digital and Software Systems
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