CHANGES.md

Change Log

Version 0.7.2 - 2023-07-24

• (fix) Fix locale fallback if user-default locale cannot be set. Fixes github #156.

Version 0.7.1 - 2023-07-20

• (fix) Fix potential division by zero crash in speedometer.

• (other) New tool header.

• (other) Source code cleanups.

• (other) Updated static build procedure (see README).

Version 0.7.0 - 2023-07-11

• (fix) FUSE/WinFsp driver now handles Unicode characters in the file system image name (the file system itself would already work properly with Unicode file names).

• (fix) Fixed heap-use-after-free when using a file system image built with brotli compression. This was caught last minute by ASAN.

• (fix) Catch errors from locale-setting at startup. These errors will only be reported now, but will no longer cause the program to abort.

• (feature) mkdwarfs command-line options have been reorganized into groups to make them easier to find and to make the default help message less intimidating. The full help can now be accessed using -H or --long-help.

• (feature) Symbolic links to the universal binary now also work as aliases on Windows.

• (test) Test universal binary in both --tool and symlink modes.

• (other) CI pipeline tweaks & fixes.

Version 0.7.0-RC6 - 2023-07-09

• (feature) Support delayed loading of WinFsp DLL for universal binary. This makes the mkdwarfs, dwarfsck and dwarfsextract tools of the universal binary usable without the WinFsp DLL.

• (perf) Optimized the offset cache to improve random read latency as well as sequential read latency. This gave a 100x higher throughput for a case where DwarFS was used to compress raw file system images. Fixes github #142.

• (fix) Fix building with make instead of ninja. Also fix builing in Debug mode. Fixes github #146.

• (fix) Fix ninja clean.

• (fix) Fix symlink creation for mount.dwarfs/mount.dwarfs2.

• (other) Added CI pipeline.

• (other) Don't write versioning files to source tree.

Version 0.7.0-RC5 - 2023-07-04

• (feature) Windows support. All tools can now be built and run on Windows, including the FUSE driver, which makes use of WinFsp.

• (feature) Build a "universal" binary that combines mkdwarfs, dwarfsck, dwarfsextract and dwarfs in a single binary. This binary can be used either through symbolic links with the proper names of the tool, or by passing --tool=<name> as the first argument on the command line.

• (feature) Bypass the block cache for uncompressed blocks. This saves copying block data to memory unnecessarily and allows us to keep all uncompressed blocks accessible directly through the memory mapping. Partially addresses github #139.

• (feature) Show throughput in the scanning and segmenting phases in mkdwarfs.

• (feature) Show how much of a file has been consumed in the segmenting phase. Useful primarily for large files.

• (feature) dwarfs and dwarfsextract now have options to enable performance monitoring. This can give insight into the latency of various file system operations.

• (feature) Added inode offset cache, which improves read() latency for very fragmented files.

• (fix) Use folly::hardware_concurrency(). Fixes github #130.

• (fix) Handle ARCHIVE_FAILED status from libarchive, which could be triggered by trying to write long path names to old archive formats.

• (fix) Properly handle unicode path truncation.

• (doc) Update file system format documentation to cover headers and section indices.

• (test) Lots of new tools tests.

• (test) Remove dependency on tar and diff binaries.

• (other) Switch to C++20.

Version 0.7.0-RC4 - 2022-12-24

• (feature) Add --compress-niceness option to mkdwarfs.

Version 0.7.0-RC3 - 2022-11-20

• (fix) Fix heap-use-after-free in dwarfsextract.

• (fix) Fix dwarfs benchmark binary.

• (feature) Add --stdout-progress option to dwarfsextract. Fixes github #117.

• (test) Reduce amount of test data to speed up compiles and avoid timeouts on travis.

Version 0.7.0-RC2 - 2022-11-17

• (fix) Fix linking against compression libs. Fixes github #112.

• (fix) Default FUSE driver debuglevel to warn in background mode. Fixes github #113.

• (feature) Add --chmod option. Fixes github #7.

• (feature) Add unreadable files as empty files. Fixes github #40.

• (doc) Document how to produce bit-identical images

• (doc) Update internal operation section of mkdwarfs manpage

• (doc) Add more documentation details for --file-hash option

• (test) Test image reproducibility for path and similarity ordering

Version 0.7.0-RC1 - 2022-11-08

• (fix) Fixed extract_block.py, which was incorrectly using printf instead of print.

• (fix) Support LZ4 compression levels above 9.

• (feature) Added --filter option to support simple (rsync-like) filter rules. This was driven by a discussion on github #6.

• (feature) Added --input-list option to support reading a list of input files from a file or stdin. At least partially fixes github #6.

• (feature) The compression code has been made more modular. This should make it much easier to add support for more compression algorithms in the future.

• (feature) Added support for Brotli compression. This is generally much slower at compression than ZSTD or LZMA, but faster than LZMA, while offering a compression ratio better than ZSTD. Fixes github #76.

• (feature) Added support for choosing the file hashing algorithm using the --file-hash option. This allows you to pick a secure hash instead of the default XXH3. Also fixes github #92.

• (feature) Improved de-duplication algorithm to only hash files with the same size. File hashing is delayed until at least one more file with the same size is discovered. This happens automatically and should improve scanning speed, especially on slow file systems.

• (feature) Added --max-similarity-size option to prevent similarity hashing of huge files. This saves scanning time, especially on slow file systems, while it shouldn't affect compression ratio too much.

• (feature) Honour user locale when formatting numbers.

• (feature) Added --num-scanner-workers option.

• (feature) Added support for extracting corrupted file systems with dwarfsextract. This is enabled using the --continue-on-error and, if really needed, --disable-integrity-check options. Fixes github #51.

• (test) Added unit tests for progress class.

• (other) Lots of internal cleanups.

Version 0.6.2 - 2022-10-24

• (fix) Fix github #91: image creation reproducibility. Add --no-create-timestamp option, produce deterministic inode numbers and fix fsst bug that causes symbol tables to be non-deterministic. Images built while omitting create timestamps will now be bit-identical.

• (fix) Fix github #93: only overwrite existing output file when --force option given on command line.

• (fix) Fix github #104: extracting large files was causing dwarfsextract to OOM. This was fixed by extracting large files in chunks rather than all at once.

• (fix) Fix github #105: handle strrchr() return NULL.

• (fix) Fix out-of-bounds access (PR #106).

• (fix) Fix swapped-out cached block detection (PR #107).

• (fix) Fix data race in cached block that was triggered by statistics collection and could cause the process to crash.

• (fix) Fix heap-use-after-free when writing section index.

Version 0.6.1 - 2022-06-11

• (fix) Fix binary installation

Version 0.6.0 - 2022-06-11

• (fix) Fix and simplify static builds as much as possible. Document how to set up a static build environment. This also fixes github #75 and github #54. Huge shoutout to Maxim Samsonov for implementing most of this!

• (fix) Fix github #71: driver hangs when unmounting

• (fix) Fix github #67: dwarfs I/O hangs if call to to fuse_reply_iov fails

• (fix) Fix github #86: block size bits config issues

• (fix) Various build fixes.

• (feature) Add support for cache tidying, which releases cache memory when the mounted file system is unused.

• (feature) Section index support for speeding up mount times (fixes github #48).

Version 0.5.6 - 2021-07-03

• (fix) Build fixes for gcc-11

• (fix) Use REALPATH in version.cmake to fix building in symbolically linked repositories (fixes github #47).

Version 0.5.5 - 2021-05-03

• (feature) 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.

• (fix) 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.

• (fix) 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.

• (fix) 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.

• (test) Add tests for binaries and FUSE driver.

• (other) Minor code cleanups.

Version 0.5.4 - 2021-04-11

• (fix) FUSE driver hangs when accessing files and the driver is not started in foreground or debug mode. This bug is present in both the 0.5.2 and 0.5.3 releases. Fixes github #44.

Version 0.5.3 - 2021-04-11

• (fix) Add PREFER_SYSTEM_GTEST for distributions (like Gentoo) that have a gtest package.

• (fix) Make sure the source tarball can be built inside a git repo. The version file generation code would attempt to pull information from any outside git repository without checking if it's actually the DwarFS repo.

Version 0.5.2 - 2021-04-07

• (fix) Make FUSE driver exit with non-zero exit code if filesystem cannot be mounted. Fixes github #41.

Version 0.5.1 - 2021-04-06

• (fix) fsst library was built with -march=native, which caused the static binaries not to work on non-AVX platforms. The fsst library is now being built with no extra flags.

Version 0.5.0 - 2021-04-05

• (fix) Disable multiversioning on non-x86 platforms, which broke the ARM build.

• (fix) Due to a bug in the bloom filter code, only half of each 64-bit block in the bloom filter was utilized, which reduced the efficiency of the filter. The bug was spotted thanks to ubsan. With the fixed filter being twice as effective, the default size of the bloom filter has now been halved.

• (fix) When exporting metadata using --export-metadata, dwarfsck was not truncating the output file, which could lead to a corrupt metadata export.

• (perf) Scanning has been significantly optimized and is now up to three times faster on average.

• (perf) Digest computation has been parallelized in both mkdwarfs and dwarfsck giving better performance on multi-core systems.

• (perf) A set of micro-benchmarks has been added to evaluate the performance of different filesystem operations. This can be build by enabling the -DWITH_BENCHMARKS=1 cmake option.

• (perf) Zstd contexts are now reused during compression, which seems to give some minor speedup.

• (feature) New metadata format (v2.3). This includes a number of changes:

  • Correct hardlink preservation. With older metadata formats, all duplicate files would appear hardlinked. The new format preserves hardlinked files exactly as present in the input data, and performs additional deduplication at a lower level.

  • The new format offers a lot of customization for additional packing of metadata. You can use these to trade off metadata size, mounting speed, etc. Especially for filesystems with millions of files, the metadata size can be reduced significantly.

  • In particular, filename and symlink data can be stored in a format that reduces the size by roughly a factor of two, but still allows for random access, so the compressed data can be mapped into memory and decompressed on the fly.

• (feature) DwarFS now directly supports images using a custom header. The header can be completely arbitrary. mkdwarfs can write, replace or remove such headers, and all other tools can either skip to a specified offset, or determine this offset automatically. This fixes github #38.

• (feature) dwarfsck has been improved to perform extensive metadata checks. Also, checksumming is now done in a thread pool, which significantly speeds up dwarfsck for large file systems.

• (feature) dwarfsck now shows a detailed breakdown of metadata memory usage, which can be used to optimize metadata packing options.

• (feature) Added ENABLE_COVERAGE cmake option.

• (test) Compatibility testing with older filesystem versions has been improved.

• (test) A new test suite has been added to check detection of corrupted DwarFS images.

• (doc) Added some high level internals documentation for mkdwarfs.

• (doc) Documented the filesystem and metadata formats.

• (other) Lots of internal cleanups.

Version 0.4.1 - 2021-03-13

• (fix) Linking against libarchive was fixed so that it also works for shared library builds. (fixes github #36)

• (fix) mkdwarfs didn't catch certain exceptions correctly, which would cause a stack trace instead of a simple error message. This has been fixed.

• (fix) The statically linked executables were unable to handle any exceptions at all due to duplicate stack unwinding code. This has (hopefully) been fixed now.

• (perf) GCC builds have traditionally been much slower than Clang builds, though it was unclear why that was the case. It turns out the reason is simply that CMake defaults to -O3 optimization, which is known to cause performance regressions in some cases. The build has been changed to always build with -O2 when doing an optimized GCC build. The Clang build is unaffected. (fixes github #14)

• (perf) The segmenting code now uses a bloom filter to discard unsuccessful matches as early and quickly as possible. While this only gives a minor speedup when using a single lookback block, as you increase the number of lookback blocks speed is barely affected whereas before it would slow down significantly. The bloom filter size (relative to the number of values) can be tuned by using --bloom-filter-size, though increasing it any further from the default is likely not going to make a difference.

• (perf) Nilsimsa similarity computation has been improved to make use of different instruction sets depending on the CPU architecture, speeding up the process of ordering files by similarity by almost a factor of 2.

• (doc) Added comparison with lrzip, zpaq. Updated wimlib comparison.

Version 0.4.0 - 2021-03-06

• (feature) New dwarfsextract tool that allows extracting a file system image. It also allows conversion of the file system image directly into a standard archive format (e.g. tar or cpio). Extracting a DwarFS image can be significantly faster than extracting a equivalent compressed archive.

• (feature) The segmenting algorithm has been completely rewritten and is now much cleaner, uses much less memory, is significantly faster and detects a lot more duplicate segments. At the same time it's easier to configure (just a single window size instead of a list).

• (feature) There's a new option --max-lookback-blocks that allows duplicate segments to be detected across multiple blocks, which can result in significantly better compression when using small file system blocks.

• (compat) The --blockhash-window-sizes and --blockhash-increment-shift options were replaced by --window-size and --window-step, respectively. The new --window-size option takes only a single window size instead of a list.

• (fix) The rewrite of the segmenting algorithm was triggered by a "bug" (github #35) that caused excessive memory consumption in mkdwarfs. It wasn't really a bug, though, more like a bad algorithm that used memory proportional to the file size. This issue has now been fully solved.

• (fix) Scanning of large files would excessively grow mkdwarfs RSS. The memory would have sooner or later be reclaimed by the kernel, but the code now actively releases the memory while scanning.

• (perf) mkdwarfs speed has been significantly improved. The 47 GiB worth of Perl installations can now be turned into a DwarFS image in less then 6 minutes, about 30% faster than with the 0.3.1 release. Using lzma compression, it actually takes less than 4 minutes now, almost twice as fast as 0.3.1.

• (perf) At the same time, compression ratio also significantly improved, mostly due to the new segmenting algorithm. With the 0.3.1 release, using the default configuration, the 47 GiB of Perl installations compressed down to 471.6 MiB. With the 0.4.0 release, this has dropped to 426.5 MiB, a 10% improvement. Using lzma compression (-l9), the size of the resulting image went from 319.5 MiB to 300.9 MiB, about 5% better. More importantly, though, the uncompressed file system size dropped from about 7 GiB to 4 GiB thanks to improved segmenting, which means less blocks need to be decompressed on average when using the file system.

• (build) The project can now be built to use the system installed zstd and xxHash libraries. (fixes github #34)

• (build) The project can now be built without the legacy FUSE driver. (fixes github #32)

• (other) Several small code cleanups.

Version 0.3.1 - 2021-01-07

• (fix) Fix linking of Python libraries

• (fix) Fix missing brace in version generator code

• (fix) Ensure the code builds fine without libdwarf

• (fix) Silence a warning and remove an unused definition

Version 0.3.0 - 2020-12-30

• (fix) File system images created with versions 0.2.2 and before did store symlinks incorrectly. While this was fixed in 0.2.3, old images could still not be read correctly. This has now been fixed and symlinks on all 0.2.x images will work correctly when using the 0.3.0+ FUSE driver.

• (fix) There was no error if the output file could not be written, mkdwarfs would just fail silently. This has now been fixed.

• (fix) When corrupted compressed blocks in either format (LZ4, ZSTD, LZMA) were detected, the FUSE driver would actually show the file contents as all zero bytes instead of signaling an I/O error. This has been fixes and verified for all formats.

• (fix) Better (hopefully) auto-detection of terminal settings to avoid using features like unicode or color when terminals don't support them. Fixes github #20.

• (fix) A number of checks has been added to make sure that corrupt file system images will not crash the binaries. In order for this to be most efficient, old images should be rewritten in the new format using:

  mkdwarfs -i old.dwarfs -o new.dwarfs --recompress none
  

• (compat) The metadata format has changed and new file system images can no longer be read by old FUSE drivers.

• (perf) Lots of tweaks and optimizations have resulted in an even better compression ratio while at the same time taking less time to build file system images. On the 48 GiB Perl dataset, for example, the compression improved from 555.7 MiB in 15m12s with 0.2.3 to 471.6 MiB in 13m59s with 0.3.0.

• (perf) Replace the cyclic hash function with the one used by rsync. The rsync hash produces similar results, but it's faster.

• (perf) mkdwarfs will now make use of hard link and inode data to avoid scanning the same inode multiple times.

• (perf) Segmenting performance has been improved by re-using data structures and thus avoiding extra memory allocations.

• (perf) All binaries now use jemalloc by default, which uses significantly less memory than glibc or tcmalloc, especially in the FUSE driver.

• (feature) New file system image format adds integrity checking as well as features for easier recovery in case of corruption. While currently there is no way to recover a corrupt file system, it is important to have the data in place sooner rather than later.

• (feature) New Python scripting support completely replaces Lua scripting. The new interface offers a lot more options and should be much easier to use.

• (feature) New nilsimsa similarity algorithm. This has become the default, as it's significantly better on my test data than the "simple" similarity algorithm.

• (feature) New option --keep-all-times to keep atime and ctime in addition to just keeping mtime.

• (feature) New option --time-resolution that allows to configure the resolution with which time stamp are stored.

• (feature) Device, FIFO and socket inodes can now be stored in DwarFS file system images. This has to be enabled with the new --with-devices and --with-specials options.

• (feature) The FUSE driver can now optionally expose correct hard link counts.

• (feature) mkdwarfs now has an option --remove-empty-dirs to remove empty directories.

• (feature) The FUSE driver has 4 new options to control caching. no_cache_image will explictly try to release compressed blocks from the file system image back to the kernel after reading. cache_image will keep them in the cache. no_cache_files will cause decompressed files not to be cached by the kernel. cache_files will cause them to be cached. The defaults are no_cache_image and cache_files.

• (feature) The FUSE driver now has a readonly option that will prevent any entries in the mounted file system to show up as writeable. This is not the default, because it interferes with setting up overlays.

• (feature) dwarfsck can now dump metadata as JSON blob.

• (feature) dwarfsck can now also export raw metadata as JSON. The difference to the --json option is that this JSON export could be used to fully reconstruct the metadata for a DwarFS image.

• (feature) More detailed logging and better error handling.

• (test) Added backwards compatibility tests.

• (build) Added zstd as a submodule.

• (build) There is now a binary package with statically linked binaries available.

• (doc) More accurate list of dependencies.

• (doc) Document how to add /etc/fstab entry for DwarFS image.

• (doc) Comparison with wimlib.

• (doc) Comparison with Cromfs.

• (doc) Comparison with EROFS.

• (doc) Updated benchmarks.

Version 0.2.4 - 2020-12-13

• Fix --set-owner and --set-group options, which caused an exception to be thrown at the end of creating a file system. (fixes github #24)

Version 0.2.3 - 2020-12-01

• Fix link handling. There were two bugs introduced with the new metadata format, one in file system creation and another in the fuse driver. You will have to re-create a file system created with dwarfs < 0.2.3 if it contained links. If you can absolutely not re-create the file system and the data is precious, let me know, there's actually a way to recover the missing data. EDIT: There will be a fix available in the 0.3.0 release, so you don't have to rebuild old file systems.

Version 0.2.2 - 2020-11-30

• Remove read-only masking as it prevents writable overlays

• Throw an error in mkdwarfs if unrecognized command line arguments are encountered (github #5)

• Various build fixes (github #2. #3)

• More documentation

Version 0.2.1 - 2020-11-29

• Replace --no-owner and --no-time with more flexible --set-owner, --set-group and --set-time options

• Update man pages

Version 0.2.0 - 2020-11-29

• Complete rewrite of the file system metadata storage using fbthrift's frozen library

Version 0.1.1 - 2020-11-23

• Test and fix Debian Buster and Ubuntu Focal builds

• Migrate from folly::StringPiece to std::string_view

• Documentation updates, list Debian/Ubuntu dependencies

Version 0.1.0 - 2020-11-22

• Initial release