EROFS No Longer Treating MicroLZMA Compression As Experimental

With Linux 6.7 the EROFS read-only file-system intended primarily for mobile devices and containers is considering their MicroLZMA compression support as stable.

Back in November 2021 with Linux 5.16 MicroLZMA compression was introduced for EROFS. The compression results were promising and MicroLZMA is one of several supported compression algorithms for per-file compression with EROFS. Two years later it's now deemed to be stable and will no longer warn users when it's being utilized. MicroLZMA yields better compression ratios than EROFS' default LZ4 compression method but at higher CPU costs. The MicroLZMA support is controlled at build-time behind the "XZ_DEC_MICROLZMA" Kconfig option.

Gao Xiang at Alibaba wrote in the patch determining it's ready to be called stable:

"The LZMA algorithm support has been landed for more than one year since Linux 5.16. Besides, the new XZ Utils 5.4 has been available in most Linux distributions."

"EXPERIMENTAL MicroLZMA in use. Use at your own risk!" is no longer dumped to the log and "LZMA support is an experimental feature for now and so most file systems will be readable without selecting this option" is also dropped from the Kconfig help text.

Besides promoting EROFS MicroLZMA compression to stable, the EROFS pull for Linux 6.7 is mostly made up of minor fixes.