Hi,
the xorriso run for testing zisofs in
tests/util/grub-fs-tester.in
looks not like it would cause any zisofs compression in the ISO.
Line 1024:
xorriso -compliance rec_mtime -set_filter_r --zisofs -- -zisofs default
-as mkisofs ... some options ... --
-set_filter_r --zisofs -- -zisofs default -add /="$MASTER" ;;
should probably become
xorriso -compliance rec_mtime \
-as mkisofs ... same options as above ... -- \
-add /="$MASTER" -- \
-zisofs default \
-set_filter_r --zisofs / --
;;
In the current run, both times when "-set_filter_r --zisofs" is executed
in xorriso's native command mode, the emerging root directory is still empty.
So -set_filter_r cannot yet affect the files of "$MASTER" which get added
only later.
Command -zisofs sets parameters for -set_filter_r. So it must be executed
before any successful -set_filter_r. Only the lack of any installed
compression filters keeps the existing run from failing with
libisofs: FAILURE : Cannot set global zisofs parameters while filters exist
Further:
Command -set_filter_r expects one or more paths in the ISO as parameters.
The empty path list defaults to "/" indeed, but that's not a documented
feature.
Command -add has a variable length parameter list and should thus be
terminated by '--'. In my proposal it has to be terminated because more
commands follow.
Experiment:
Currently the run is essentially like
xorriso -compliance rec_mtime \
-as mkisofs -o test.iso --graft-points -- \
-add /=test -- -set_filter_r --zisofs / --
My test directory contains
-rw-r--r-- 1 thomas thomas 51200 Aug 25 11:51 zeros
-rw-r--r-- 1 thomas thomas 6 Aug 25 09:37 ÄÖÜß
No zisofs compression gets applied by above run to the files, as can be
seen by a subsequent run of
xorriso -indev test.iso -find / -exec show_stream --
which reports
'/zeros' < image:'/zeros'
'/ÄÖÜß' < image:'/ÄÖÜß'
In contrast, my proposed xorriso run causes compression of file "zeros",
which then causes the xorriso run with -indev to install a decompression
filter to that file:
'/zeros' < --zisofs-decode:pz:32k < image:'/zeros'
'/ÄÖÜß' < image:'/ÄÖÜß'
The small "ÄÖÜß" staid uncompressed, because compression yielded no gain in
terms of 2048 byte blocks.
Have a nice day :)
Thomas
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