>From: Gary Houston <[EMAIL PROTECTED]>

>I have been using dvd+rw-tools (5.13.4.7.4) and mkisofs (cdrtools 1.11a29)
>to write backups to DVD.  This generally works.  However I encountered
>a problem when one of the files was 2351679431 bytes in size: the disk
>was written with no errors reported, but on testing proved to be unreadable
>to linux 2.4.21.  On mounting the disk a warning was reported:

>Warning: defective CD-ROM.  Enabling "cruft" mount option.

>The large file now appeared to be only 2869191 bytes and is truncated
>on reading.

>Examining the Linux sources shows the following comment in fs/isofs/inode.c:

>       /*
>        * The ISO-9660 filesystem only stores 32 bits for file size.
>        * mkisofs handles files up to 2GB-2 = 2147483646 = 0x7FFFFFFE bytes
>        * in size. This is according to the large file summit paper from 1996.
>        * WARNING: ISO-9660 filesystems > 1 GB and even > 2 GB are fully
>        *          legal. Do not prevent to use DVD's [EMAIL PROTECTED]
>        */
>       if ((inode->i_size < 0 || inode->i_size > 0x7FFFFFFE) &&
>           inode->i_sb->u.isofs_sb.s_cruft == 'n') {
>               printk(KERN_WARNING "Warning: defective CD-ROM.  "
>                      "Enabling \"cruft\" mount option.\n");
>               inode->i_sb->u.isofs_sb.s_cruft = 'y';
>       }

The hacky change is from me, but note:

-       As the source before did not support files > 512 MB, nobody could
        have tested multi extent files! 

-       If I would have removed the "limitation" completely, it would most 
        likely not have been accepted as a patch :-(



J�rg

-- 
 EMail:[EMAIL PROTECTED] (home) J�rg Schilling D-13353 Berlin
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 URL:  http://www.fokus.fraunhofer.de/usr/schilling ftp://ftp.berlios.de/pub/schily


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