[regression] linux: Loop-mounted UDF ISOs no longer readable

[Salvatore Bonaccorso <carnil@debian.org>]

Hi Jan, hi Zhao,

In Debian we got he following report, full quoted below from Daniel
Reichelt, dass after updating to 6.1.115 (and later, confirmed up to
6.1.119), loop-mounted UDF ISOs are no longer readable:

> Hi,
> 
> in 6.1.112-1 I could loop-mount Windows Setup ISOs (downloaded from M$; hashes
> are fine; 10/11, DE/EN don't seem to make any difference) and access their
> content perfectly fine, i.e. share the /sources/ sub-directory via samba for
> netinstall scenarios.
> 
> Starting with 6.1.115-1, the ISOs can be mounted, the root-dir is accessible
> and `stat $mntpt/sources` gives output as well. However `ls $mntpt/sources`
> hangs and the kernel log is spammed with entries like
> 
> ---------------8<-------------------------
> 2024-12-11T14:53:19.616728+01:00 srv kernel: [182394.024828] UDF-fs: error (device loop3): udf_fiiter_advance_blk: extent after position 12272 not allocated in directory (ino 312)
> 2024-12-11T14:53:19.629970+01:00 srv kernel: [182394.038041] UDF-fs: error (device loop3): udf_verify_fi: directory (ino 312) has too big (2088) entry at pos 12272
> 2024-12-11T14:53:19.641623+01:00 srv kernel: [182394.049714] UDF-fs: error (device loop3): udf_fiiter_advance_blk: extent after position 12272 not allocated in directory (ino 312)
> 2024-12-11T14:53:19.654841+01:00 srv kernel: [182394.062928] UDF-fs: error (device loop3): udf_verify_fi: directory (ino 312) has too big (2088) entry at pos 12272
> 2024-12-11T14:53:19.666495+01:00 srv kernel: [182394.074615] UDF-fs: error (device loop3): udf_fiiter_advance_blk: extent after position 12272 not allocated in directory (ino 312)
> 2024-12-11T14:53:19.679747+01:00 srv kernel: [182394.087833] UDF-fs: error (device loop3): udf_verify_fi: directory (ino 312) has too big (2088) entry at pos 12272
> 2024-12-11T14:53:19.691394+01:00 srv kernel: [182394.099510] UDF-fs: error (device loop3): udf_fiiter_advance_blk: extent after position 12272 not allocated in directory (ino 312)
> 2024-12-11T14:53:19.704646+01:00 srv kernel: [182394.112727] UDF-fs: error (device loop3): udf_verify_fi: directory (ino 312) has too big (2088) entry at pos 12272
> 2024-12-11T14:53:19.716283+01:00 srv kernel: [182394.124400] UDF-fs: error (device loop3): udf_fiiter_advance_blk: extent after position 12272 not allocated in directory (ino 312)
> 2024-12-11T14:53:19.729539+01:00 srv kernel: [182394.137618] UDF-fs: error (device loop3): udf_verify_fi: directory (ino 312) has too big (2088) entry at pos 12272
> 2024-12-11T14:53:19.741185+01:00 srv kernel: [182394.149279] UDF-fs: error (device loop3): udf_fiiter_advance_blk: extent after position 12272 not allocated in directory (ino 312)
> 2024-12-11T14:53:19.754422+01:00 srv kernel: [182394.162494] UDF-fs: error (device loop3): udf_verify_fi: directory (ino 312) has too big (2088) entry at pos 12272
> 2024-12-11T14:53:19.766071+01:00 srv kernel: [182394.174159] UDF-fs: error (device loop3): udf_fiiter_advance_blk: extent after position 12272 not allocated in directory (ino 312)
> 2024-12-11T14:53:19.779289+01:00 srv kernel: [182394.187375] UDF-fs: error (device loop3): udf_verify_fi: directory (ino 312) has too big (2088) entry at pos 12272
> ---------------8<-------------------------
> 
> 
> 6.1.119-1 shows the same behaviour.
> Let me know if you need additional info.

We have not a full bisect, but Daniel confirmed already in
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1089698#22 some
observations:

> OK:
>   6.1.112-1
> BAD:
>   6.1.115-1
>   6.1.119-1
> OK again:
>   6.3.1-1~exp1
>   current trixie
>   current sid

(current trixie is 6.11.10 based kernel, current sid is based on
6.12.5 kernel).

Dies this ring some bell to you?

#regzbot introduced: v6.1.112..v6.1.115
#regzbot monitor: https://bugs.debian.org/1089698

Regards,
Salvatore