File size damage by non-unique inode numbers of pre-RRIP 1.12 images

[scdbackup]

libisofs produces non-unique inode numbers with empty regular files when reading from images which are not marked by ER signature "IEEE_1282".

This confuses file sizes if the files happen to share an inode.

The fallback st_ino generator seems insufficient if zero length files are in the image:

    atts.st_ino = (ino_t) iso_read_bb(record->block, 4, NULL);

I examine my damaged image by help of iso_stream_get_id(). A file with righteous size 0:

  /stic_dir/this_is_the_stic_main_directory
  xorriso_debug: iso_ino= 11344

the next file in the directory should be 94 bytes long

  /stic_dir/where_to_publish
  xorriso_debug: iso_ino= 11344

but it now shows the same size 0 as its neighbor.

---

More:

The inode reader is inconsistent because in fs_image.c there is a test for RR_EXT_112 whereas in rockridge_read.c the length of the PX field decides whether the inode number is read from image.

---

The bug showed up when i began to write the old "RRIP_1991A" signature rather than "IEEE_1282" into the ER field.

When searching for consequences of RRIP_1991A versus IEEE_1282 i found only this in libisofs/fs_image.c:

    if (fsdata->rr != RR_EXT_112) {
        /*
         * Only RRIP 1.12 provides valid inode numbers. If not, it is not easy
         * to generate those serial numbers, and we use extend block instead.
         * It BREAKS POSIX SEMANTICS, but its suitable for our needs
         */
        atts.st_ino = (ino_t) iso_read_bb(record->block, 4, NULL);
        if (fsdata->rr == 0) {
            atts.st_nlink = 1;
        }
    }

If i disable it then the bug is gone.

What data extent block number has a file of size 0 ? What would be the consequence of non-unique inodes ?

But why do they become unique enough in later sessions ? What effect sorts them apart resp makes the ino sharers have the same st_size ? This stays a riddle.

I replaced the ino generator by

        {
            static ino_t iso_global_inode= 0;

            if(iso_global_inode <= 0)
                iso_global_inode++;
            atts.st_ino = iso_global_inode++;
        }

and again the bug is gone.

This is now change "ts A81118" in xorriso-standalone.

[scdbackup]

For the unlikely case that ino_t is signed it should rather be {{{ {

static ino_t iso_global_inode= 0;

if(iso_global_inode <= 0)

iso_global_inode= 1;

atts.st_ino = iso_global_inode++;

}

}}}

[scdbackup]

This has been fixed by release of libisofs-0.6.10.pl01