Release dwarfs-0.5.5 · mhx/dwarfs

Features

If a filesystem block cannot be compressed to less than the uncompressed size, it will be stored uncompressed. This feature actually fixes the bug described below.

When building a filesystem from high entropy input data (e.g. already compressed files), and when using LZMA compression with block sizes >= 25, the LZMA algorithm could be unable to pack a block into the worst-case allocated size. This behaviour was not expected and crashed mkdwarfs, and seems to me like a bug in LZMA's lzma_stream_buffer_bound() function. The issue has been fixed by not compressing blocks at all if the compressed size matches or exceeds the uncompressed size. This fixes part of github #45.
Filesystems created such that after segmenting the total data size was a multiple of the block size (i.e. the last block was completely filled) had the last block written to the image twice. Such a filesystem image is perfectly usable, but the repeated block uses space unnecessarily. This is highly unlikely to happen with real data.
Filesystems created with -P shared_files, but no shared files in the source tree, were created correctly, but could not be loaded. This has been fixed and the filesystems can now be loaded correctly.