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path: root/fs/erofs/decompressor.c
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2021-10-31erofs: don't trigger WARN() when decompression failsGao Xiang
syzbot reported a WARNING [1] due to corrupted compressed data. As Dmitry said, "If this is not a kernel bug, then the code should not use WARN. WARN if for kernel bugs and is recognized as such by all testing systems and humans." [1] https://lore.kernel.org/r/000000000000b3586105cf0ff45e@google.com Link: https://lore.kernel.org/r/20211025074311.130395-1-hsiangkao@linux.alibaba.com Cc: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Chao Yu <chao@kernel.org> Reported-by: syzbot+d8aaffc3719597e8cfb4@syzkaller.appspotmail.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-25erofs: get rid of ->lru usageGao Xiang
Currently, ->lru is a way to arrange non-LRU pages and has some in-kernel users. In order to minimize noticable issues of page reclaim and cache thrashing under high memory presure, limited temporary pages were all chained with ->lru and can be reused during the request. However, it seems that ->lru could be removed when folio is landing. Let's use page->private to chain temporary pages for now instead and transform EROFS formally after the topic of the folio / file page design is finalized. Link: https://lore.kernel.org/r/20211022090120.14675-1-hsiangkao@linux.alibaba.com Cc: Matthew Wilcox <willy@infradead.org> Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-19erofs: lzma compression supportGao Xiang
Add MicroLZMA support in order to maximize compression ratios for specific scenarios. For example, it's useful for low-end embedded boards and as a secondary algorithm in a file for specific access patterns. MicroLZMA is a new container format for raw LZMA1, which was created by Lasse Collin aiming to minimize old LZMA headers and get rid of unnecessary EOPM (end of payload marker) as well as to enable fixed-sized output compression, especially for 4KiB pclusters. Similar to LZ4, inplace I/O approach is used to minimize runtime memory footprint when dealing with I/O. Overlapped decompression is handled with 1) bounced buffer for data under processing or 2) extra short-lived pages from the on-stack pagepool which will be shared in the same read request (128KiB for example). Link: https://lore.kernel.org/r/20211010213145.17462-8-xiang@kernel.org Acked-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-19erofs: rename some generic methods in decompressorGao Xiang
Previously, some LZ4 methods were named with `generic'. However, while evaluating the effective LZMA approach, it seems they aren't quite generic at all (e.g. no need preparing dstpages for most LZMA cases.) Avoid such naming instead. Link: https://lore.kernel.org/r/20211010213145.17462-7-xiang@kernel.org Acked-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-15erofs: remove the fast path of per-CPU buffer decompressionYue Hu
As Xiang mentioned, such path has no real impact to our current decompression strategy, remove it directly. Also, update the return value of z_erofs_lz4_decompress() to 0 if success to keep consistent with LZMA which will return 0 as well for that case. Link: https://lore.kernel.org/r/20211014065744.1787-1-zbestahu@gmail.com Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Yue Hu <huyue2@yulong.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-06-08erofs: clean up file headers & footersGao Xiang
- Remove my outdated misleading email address; - Get rid of all unnecessary trailing newline by accident. Link: https://lore.kernel.org/r/20210602160634.10757-1-xiang@kernel.org Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-04-10erofs: support decompress big pcluster for lz4 backendGao Xiang
Prior to big pcluster, there was only one compressed page so it'd easy to map this. However, when big pcluster is enabled, more work needs to be done to handle multiple compressed pages. In detail, - (maptype 0) if there is only one compressed page + no need to copy inplace I/O, just map it directly what we did before; - (maptype 1) if there are more compressed pages + no need to copy inplace I/O, vmap such compressed pages instead; - (maptype 2) if inplace I/O needs to be copied, use per-CPU buffers for decompression then. Another thing is how to detect inplace decompression is feasable or not (it's still quite easy for non big pclusters), apart from the inplace margin calculation, inplace I/O page reusing order is also needed to be considered for each compressed page. Currently, if the compressed page is the xth page, it shouldn't be reused as [0 ... nrpages_out - nrpages_in + x], otherwise a full copy will be triggered. Although there are some extra optimization ideas for this, I'd like to make big pcluster work correctly first and obviously it can be further optimized later since it has nothing with the on-disk format at all. Link: https://lore.kernel.org/r/20210407043927.10623-10-xiang@kernel.org Acked-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
2021-04-10erofs: adjust per-CPU buffers according to max_pclusterblksGao Xiang
Adjust per-CPU buffers on demand since big pcluster definition is available. Also, bail out unsupported pcluster size according to Z_EROFS_PCLUSTER_MAX_SIZE. Link: https://lore.kernel.org/r/20210407043927.10623-7-xiang@kernel.org Acked-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
2021-04-10erofs: introduce multipage per-CPU buffersGao Xiang
To deal the with the cases which inplace decompression is infeasible for some inplace I/O. Per-CPU buffers was introduced to get rid of page allocation latency and thrash for low-latency decompression algorithms such as lz4. For the big pcluster feature, introduce multipage per-CPU buffers to keep such inplace I/O pclusters temporarily as well but note that per-CPU pages are just consecutive virtually. When a new big pcluster fs is mounted, its max pclustersize will be read and per-CPU buffers can be growed if needed. Shrinking adjustable per-CPU buffers is more complex (because we don't know if such size is still be used), so currently just release them all when unloading. Link: https://lore.kernel.org/r/20210409190630.19569-1-xiang@kernel.org Acked-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
2021-03-29erofs: add on-disk compression configurationsGao Xiang
Add a bitmap for available compression algorithms and a variable-sized on-disk table for compression options in preparation for upcoming big pcluster and LZMA algorithm, which follows the end of super block. To parse the compression options, the bitmap is scanned one by one. For each available algorithm, there is data followed by 2-byte `length' correspondingly (it's enough for most cases, or entire fs blocks should be used.) With such available algorithm bitmap, kernel itself can also refuse to mount such filesystem if any unsupported compression algorithm exists. Note that COMPR_CFGS feature will be enabled with BIG_PCLUSTER. Link: https://lore.kernel.org/r/20210329100012.12980-1-hsiangkao@aol.com Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
2021-03-29erofs: introduce on-disk lz4 fs configurationsGao Xiang
Introduce z_erofs_lz4_cfgs to store all lz4 configurations. Currently it's only max_distance, but will be used for new features later. Link: https://lore.kernel.org/r/20210329012308.28743-4-hsiangkao@aol.com Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
2021-03-29erofs: support adjust lz4 history window sizeHuang Jianan
lz4 uses LZ4_DISTANCE_MAX to record history preservation. When using rolling decompression, a block with a higher compression ratio will cause a larger memory allocation (up to 64k). It may cause a large resource burden in extreme cases on devices with small memory and a large number of concurrent IOs. So appropriately reducing this value can improve performance. Decreasing this value will reduce the compression ratio (except when input_size <LZ4_DISTANCE_MAX). But considering that erofs currently only supports 4k output, reducing this value will not significantly reduce the compression benefits. The maximum value of LZ4_DISTANCE_MAX defined by lz4 is 64k, and we can only reduce this value. For the old kernel, it just can't reduce the memory allocation during rolling decompression without affecting the decompression result. Link: https://lore.kernel.org/r/20210329012308.28743-3-hsiangkao@aol.com Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Huang Jianan <huangjianan@oppo.com> Signed-off-by: Guo Weichao <guoweichao@oppo.com> [ Gao Xiang: introduce struct erofs_sb_lz4_info for configurations. ] Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
2021-03-29erofs: introduce erofs_sb_has_xxx() helpersGao Xiang
Introduce erofs_sb_has_xxx() to make long checks short, especially for later big pcluster & LZMA features. Link: https://lore.kernel.org/r/20210329012308.28743-2-hsiangkao@aol.com Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
2021-03-29erofs: avoid memory allocation failure during rolling decompressionHuang Jianan
Currently, err would be treated as io error. Therefore, it'd be better to ensure memory allocation during rolling decompression to avoid such io error. In the long term, we might consider adding another !Uptodate case for such case. Link: https://lore.kernel.org/r/20210316031515.90954-1-huangjianan@oppo.com Reviewed-by: Gao Xiang <hsiangkao@redhat.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Huang Jianan <huangjianan@oppo.com> Signed-off-by: Guo Weichao <guoweichao@oppo.com> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
2020-12-08erofs: get rid of magical Z_EROFS_MAPPING_STAGINGGao Xiang
Previously, we played around with magical page->mapping for short-lived temporary pages since we need to identify different types of pages in the same pcluster but both invalidated and short-lived temporary pages can have page->mapping == NULL. It was considered as safe because that temporary pages are all non-LRU / non-movable pages. This patch tends to use specific page->private to identify short-lived pages instead so it won't rely on page->mapping anymore. Details are described in "compress.h" as well. Link: https://lore.kernel.org/r/20201208095834.3133565-1-hsiangkao@redhat.com Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
2020-08-03erofs: Replace HTTP links with HTTPS onesAlexander A. Klimov
Rationale: Reduces attack surface on kernel devs opening the links for MITM as HTTPS traffic is much harder to manipulate. Deterministic algorithm: For each file: If not .svg: For each line: If doesn't contain `\bxmlns\b`: For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`: If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`: If both the HTTP and HTTPS versions return 200 OK and serve the same content: Replace HTTP with HTTPS. Reviewed-by: Gao Xiang <hsiangkao@redhat.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de> Link: https://lore.kernel.org/r/20200713130944.34419-1-grandmaster@al2klimov.de Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
2020-06-02mm: remove the prot argument from vm_map_ramChristoph Hellwig
This is always PAGE_KERNEL - for long term mappings with other properties vmap should be used. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Airlie <airlied@linux.ie> Cc: Gao Xiang <xiang@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Laura Abbott <labbott@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Michael Kelley <mikelley@microsoft.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Wei Liu <wei.liu@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/20200414131348.444715-19-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-03-03erofs: handle corrupted images whose decompressed size less than it'd beGao Xiang
As Lasse pointed out, "Looking at fs/erofs/decompress.c, the return value from LZ4_decompress_safe_partial is only checked for negative value to catch errors. ... So if I understood it correctly, if there is bad data whose uncompressed size is much less than it should be, it can leave part of the output buffer untouched and expose the previous data as the file content. " Let's fix it now. Cc: Lasse Collin <lasse.collin@tukaani.org> Fixes: 7fc45dbc938a ("staging: erofs: introduce generic decompression backend") [ Gao Xiang: v5.3+, I will manually backport this to stable later. ] Link: https://lore.kernel.org/r/20200226081008.86348-3-gaoxiang25@huawei.com Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
2020-03-03erofs: use LZ4_decompress_safe() for full decodingGao Xiang
As Lasse pointed out, "EROFS uses LZ4_decompress_safe_partial for both partial and full blocks. Thus when it is decoding a full block, it doesn't know if the LZ4 decoder actually decoded all the input. The real uncompressed size could be bigger than the value stored in the file system metadata. Using LZ4_decompress_safe instead of _safe_partial when decompressing a full block would help to detect errors." So it's reasonable to use _safe in case of potential corrupted images and it might have some speed gain as well although I didn't observe much difference. Note that legacy compressor (< 5.3, no LZ4_0PADDING) could encode extra data in a pcluster, which is excluded as well. Cc: Lasse Collin <lasse.collin@tukaani.org> Fixes: 0ffd71bcc3a0 ("staging: erofs: introduce LZ4 decompression inplace") [ Gao Xiang: v5.3+, I will manually backport this to stable later. ] Link: https://lore.kernel.org/r/20200226081008.86348-2-gaoxiang25@huawei.com Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
2020-01-11erofs: fix out-of-bound read for shifted uncompressed blockGao Xiang
rq->out[1] should be valid before accessing. Otherwise, in very rare cases, out-of-bound dirty onstack rq->out[1] can equal to *in and lead to unintended memmove behavior. Link: https://lore.kernel.org/r/20200107022546.19432-1-gaoxiang25@huawei.com Fixes: 7fc45dbc938a ("staging: erofs: introduce generic decompression backend") Cc: <stable@vger.kernel.org> # 5.3+ Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
2019-11-24erofs: get rid of __stagingpage_alloc helperGao Xiang
Now open code is much cleaner due to iterative development. Link: https://lore.kernel.org/r/20191124025217.12345-1-hsiangkao@aol.com Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
2019-09-05erofs: rename errln/infoln/debugln to erofs_{err, info, dbg}Gao Xiang
Add prefix "erofs_" to these functions and print sb->s_id as a prefix to erofs_{err, info} so that the user knows which file system is affected. Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> Link: https://lore.kernel.org/r/20190904020912.63925-23-gaoxiang25@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-05erofs: kill use_vmap module parameterGao Xiang
As Christoph said [1], "vm_map_ram is supposed to generally behave better. So if it doesn't please report that that to the arch maintainer and linux-mm so that they can look into the issue. Having user make choices of deep down kernel internals is just a horrible interface. Please talk to maintainers of other bits of the kernel if you see issues and / or need enhancements. " Let's redo the previous conclusion and kill the vmap approach. [1] https://lore.kernel.org/r/20190830165533.GA10909@infradead.org/ Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> Link: https://lore.kernel.org/r/20190904020912.63925-21-gaoxiang25@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-05erofs: add "erofs_" prefix for common and short functionsGao Xiang
Add erofs_ prefix to free_inode, alloc_inode, ... Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> Link: https://lore.kernel.org/r/20190904020912.63925-19-gaoxiang25@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-05erofs: use feature_incompat rather than requirementsGao Xiang
As Christoph said [1], "This is only cosmetic, why not stick to feature_compat and feature_incompat?" In my thought, requirements means "incompatible" instead of "feature" though. [1] https://lore.kernel.org/r/20190902125109.GA9826@infradead.org/ Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> Link: https://lore.kernel.org/r/20190904020912.63925-7-gaoxiang25@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-30erofs: remove all likely/unlikely annotationsGao Xiang
As Dan Carpenter suggested [1], I have to remove all erofs likely/unlikely annotations. [1] https://lore.kernel.org/linux-fsdevel/20190829154346.GK23584@kadam/ Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> Link: https://lore.kernel.org/r/20190829163827.203274-1-gaoxiang25@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-24erofs: move erofs out of stagingGao Xiang
EROFS filesystem has been merged into linux-staging for a year. EROFS is designed to be a better solution of saving extra storage space with guaranteed end-to-end performance for read-only files with the help of reduced metadata, fixed-sized output compression and decompression inplace technologies. In the past year, EROFS was greatly improved by many people as a staging driver, self-tested, betaed by a large number of our internal users, successfully applied to almost all in-service HUAWEI smartphones as the part of EMUI 9.1 and proven to be stable enough to be moved out of staging. EROFS is a self-contained filesystem driver. Although there are still some TODOs to be more generic, we have a dedicated team actively keeping on working on EROFS in order to make it better with the evolution of Linux kernel as the other in-kernel filesystems. As Pavel suggested, it's better to do as one commit since git can do moves and all histories will be saved in this way. Let's promote it from staging and enhance it more actively as a "real" part of kernel for more wider scenarios! Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Pavel Machek <pavel@denx.de> Cc: David Sterba <dsterba@suse.cz> Cc: Amir Goldstein <amir73il@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Darrick J . Wong <darrick.wong@oracle.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Richard Weinberger <richard@nod.at> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Chao Yu <yuchao0@huawei.com> Cc: Miao Xie <miaoxie@huawei.com> Cc: Li Guifu <bluce.liguifu@huawei.com> Cc: Fang Wei <fangwei1@huawei.com> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> Link: https://lore.kernel.org/r/20190822213659.5501-1-hsiangkao@aol.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>