kernel.git/fs/erofs/decompressor.c, branch linux-6.7.y

erofs: fix lz4 inplace decompression

2024-02-01T00:20:54Z

commit 3c12466b6b7bf1e56f9b32c366a3d83d87afb4de upstream. Currently EROFS can map another compressed buffer for inplace decompression, that was used to handle the cases that some pages of compressed data are actually not in-place I/O. However, like most simple LZ77 algorithms, LZ4 expects the compressed data is arranged at the end of the decompressed buffer and it explicitly uses memmove() to handle overlapping: __________________________________________________________ |_ direction of decompression --> ____ |_ compressed data _| Although EROFS arranges compressed data like this, it typically maps two individual virtual buffers so the relative order is uncertain. Previously, it was hardly observed since LZ4 only uses memmove() for short overlapped literals and x86/arm64 memmove implementations seem to completely cover it up and they don't have this issue. Juhyung reported that EROFS data corruption can be found on a new Intel x86 processor. After some analysis, it seems that recent x86 processors with the new FSRM feature expose this issue with "rep movsb". Let's strictly use the decompressed buffer for lz4 inplace decompression for now. Later, as an useful improvement, we could try to tie up these two buffers together in the correct order. Reported-and-tested-by: Juhyung Park Closes: https://lore.kernel.org/r/CAD14+f2AVKf8Fa2OO1aAUdDNTDsVzzR6ctU_oJSmTyd6zSYR2Q@mail.gmail.com Fixes: 0ffd71bcc3a0 ("staging: erofs: introduce LZ4 decompression inplace") Fixes: 598162d05080 ("erofs: support decompress big pcluster for lz4 backend") Cc: stable # 5.4+ Tested-by: Yifan Zhao Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20231206045534.3920847-1-hsiangkao@linux.alibaba.com Signed-off-by: Greg Kroah-Hartman

erofs: fix inconsistent per-file compression format

2024-01-25T23:45:27Z

[ Upstream commit 118a8cf504d7dfa519562d000f423ee3ca75d2c4 ] EROFS can select compression algorithms on a per-file basis, and each per-file compression algorithm needs to be marked in the on-disk superblock for initialization. However, syzkaller can generate inconsistent crafted images that use an unsupported algorithmtype for specific inodes, e.g. use MicroLZMA algorithmtype even it's not set in `sbi->available_compr_algs`. This can lead to an unexpected "BUG: kernel NULL pointer dereference" if the corresponding decompressor isn't built-in. Fix this by checking against `sbi->available_compr_algs` for each m_algorithmformat request. Incorrect !erofs_sb_has_compr_cfgs preset bitmap is now fixed together since it was harmless previously. Reported-by: Fixes: 8f89926290c4 ("erofs: get compression algorithms directly on mapping") Fixes: 622ceaddb764 ("erofs: lzma compression support") Reviewed-by: Yue Hu Link: https://lore.kernel.org/r/20240113150602.1471050-1-hsiangkao@linux.alibaba.com Signed-off-by: Gao Xiang Signed-off-by: Sasha Levin

erofs: tidy up redundant includes

2023-10-30T22:58:49Z

- Remove unused includes like and ; - Move common includes into "internal.h". Signed-off-by: Ferry Meng Reviewed-by: Gao Xiang Reviewed-by: Yue Hu Reviewed-by: Chao Yu Link: https://lore.kernel.org/r/20231026021627.23284-2-mengferry@linux.alibaba.com Signed-off-by: Gao Xiang

erofs: simplify compression configuration parser

2023-10-30T22:57:19Z

Move erofs_load_compr_cfgs() into decompressor.c as well as introduce a callback instead of a hard-coded switch for each algorithm for simplicity. Reviewed-by: Chao Yu Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20231022130957.11398-1-xiang@kernel.org

erofs: DEFLATE compression support

2023-08-11T04:11:17Z

Add DEFLATE compression as the 3rd supported algorithm. DEFLATE is a popular generic-purpose compression algorithm for quite long time (many advanced formats like gzip, zlib, zip, png are all based on that) as Apple documentation written "If you require interoperability with non-Apple devices, use COMPRESSION_ZLIB. [1]". Due to its popularity, there are several hardware on-market DEFLATE accelerators, such as (s390) DFLTCC, (Intel) IAA/QAT, (HiSilicon) ZIP accelerator, etc. In addition, there are also several high-performence IP cores and even open-source FPGA approches available for DEFLATE. Therefore, it's useful to support DEFLATE compression in order to find a way to utilize these accelerators for asynchronous I/Os and get benefits from these later. Besides, it's a good choice to trade off between compression ratios and performance compared to LZ4 and LZMA. The DEFLATE core format is simple as well as easy to understand, therefore the code size of its decompressor is small even for the bootloader use cases. The runtime memory consumption is quite limited too (e.g. 32K + ~7K for each zlib stream). As usual, EROFS ourperforms similar approaches too. Alternatively, DEFLATE could still be used for some specific files since EROFS supports multiple compression algorithms in one image. [1] https://developer.apple.com/documentation/compression/compression_algorithm Reviewed-by: Chao Yu Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20230810154859.118330-1-hsiangkao@linux.alibaba.com

erofs: simplify z_erofs_transform_plain()

2023-07-11T16:50:15Z

Use memcpy_to_page() instead of open-coding them. In addition, add a missing flush_dcache_page() even though almost all modern architectures clear `PG_dcache_clean` flag for new file cache pages so that it doesn't change anything in practice. Signed-off-by: Gao Xiang Reviewed-by: Yue Hu Reviewed-by: Chao Yu Link: https://lore.kernel.org/r/20230627161240.331-2-hsiangkao@linux.alibaba.com Signed-off-by: Gao Xiang

erofs: get rid of the remaining kmap_atomic()

2023-07-11T16:49:39Z

It's unnecessary to use kmap_atomic() compared with kmap_local_page(). In addition, kmap_atomic() is deprecated now. Signed-off-by: Gao Xiang Reviewed-by: Yue Hu Reviewed-by: Chao Yu Link: https://lore.kernel.org/r/20230627161240.331-1-hsiangkao@linux.alibaba.com Signed-off-by: Gao Xiang

erofs: fold in z_erofs_decompress()

2023-05-29T07:54:49Z

No need this helper since it's just a simple wrapper for decompress method and only one caller. So, let's fold in directly instead. Signed-off-by: Yue Hu Reviewed-by: Gao Xiang Link: https://lore.kernel.org/r/20230426084449.12781-1-zbestahu@gmail.com Signed-off-by: Gao Xiang

erofs: avoid hardcoded blocksize for subpage block support

2023-04-16T17:15:44Z

As the first step of converting hardcoded blocksize to that specified in on-disk superblock, convert all call sites of hardcoded blocksize to sb->s_blocksize except for: 1) use sbi->blkszbits instead of sb->s_blocksize in erofs_superblock_csum_verify() since sb->s_blocksize has not been updated with the on-disk blocksize yet when the function is called. 2) use inode->i_blkbits instead of sb->s_blocksize in erofs_bread(), since the inode operated on may be an anonymous inode in fscache mode. Currently the anonymous inode is allocated from an anonymous mount maintained in erofs, while in the near future we may allocate anonymous inodes from a generic API directly and thus have no access to the anonymous inode's i_sb. Thus we keep the block size in i_blkbits for anonymous inodes in fscache mode. Be noted that this patch only gets rid of the hardcoded blocksize, in preparation for actually setting the on-disk block size in the following patch. The hard limit of constraining the block size to PAGE_SIZE still exists until the next patch. Signed-off-by: Jingbo Xu Reviewed-by: Gao Xiang Reviewed-by: Yue Hu Reviewed-by: Chao Yu Link: https://lore.kernel.org/r/20230313135309.75269-2-jefflexu@linux.alibaba.com [ Gao Xiang: fold a patch to fix incorrect truncated offsets. ] Link: https://lore.kernel.org/r/20230413035734.15457-1-zhujia.zj@bytedance.com Signed-off-by: Gao Xiang

erofs: support interlaced uncompressed data for compressed files

2022-09-23T02:55:56Z

Currently, uncompressed data is all handled in the shifted way, which means we have to shift the whole on-disk plain pcluster to get the logical data. However, since we are also using in-place I/O for uncompressed data, data copy will be reduced a lot if pcluster is recorded in the interlaced way as illustrated below: _______________________________________________________________ | | | |_ tail part |_ head part _| |<- blk0 ->| .. |<- blkn-2 ->|<- blkn-1 ->| The logical data then becomes: ________________________________________________________ |_ head part _|_ blk0 _| .. |_ blkn-2 _|_ tail part _| In addition, non-4k plain pclusters are also survived by the interlaced way, which can be used for non-4k lclusters as well. However, it's almost impossible to de-duplicate uncompressed data in the interlaced way, therefore shifted uncompressed data is still useful. Signed-off-by: Yue Hu Reviewed-by: Gao Xiang Link: https://lore.kernel.org/r/8369112678604fdf4ef796626d59b1fdd0745a53.1663898962.git.huyue2@coolpad.com Signed-off-by: Gao Xiang