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* erofs: mark experimental fscache backend deprecatedGao Xiang2024-09-101-1/+4
| | | | | | | | | | | | | | | | Although fscache is still described as "General Filesystem Caching" for network filesystems and other things such as ISO9660 filesystems, it has actually become a part of netfslib recently, which was unexpected at the time when "EROFS over fscache" proposed (2021) since EROFS is entirely a disk filesystem and the dependency is redundant. Mark it deprecated and it will be removed after "fanotify pre-content hooks" lands, which will provide the same functionality for EROFS. Reviewed-by: Sandeep Dhavale <dhavale@google.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240830032840.3783206-4-hsiangkao@linux.alibaba.com
* erofs: add file-backed mount supportGao Xiang2024-09-101-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It actually has been around for years: For containers and other sandbox use cases, there will be thousands (and even more) of authenticated (sub)images running on the same host, unlike OS images. Of course, all scenarios can use the same EROFS on-disk format, but bdev-backed mounts just work well for OS images since golden data is dumped into real block devices. However, it's somewhat hard for container runtimes to manage and isolate so many unnecessary virtual block devices safely and efficiently [1]: they just look like a burden to orchestrators and file-backed mounts are preferred indeed. There were already enough attempts such as Incremental FS, the original ComposeFS and PuzzleFS acting in the same way for immutable fses. As for current EROFS users, ComposeFS, containerd and Android APEXs will be directly benefited from it. On the other hand, previous experimental feature "erofs over fscache" was once also intended to provide a similar solution (inspired by Incremental FS discussion [2]), but the following facts show file-backed mounts will be a better approach: - Fscache infrastructure has recently been moved into new Netfslib which is an unexpected dependency to EROFS really, although it originally claims "it could be used for caching other things such as ISO9660 filesystems too." [3] - It takes an unexpectedly long time to upstream Fscache/Cachefiles enhancements. For example, the failover feature took more than one year, and the deamonless feature is still far behind now; - Ongoing HSM "fanotify pre-content hooks" [4] together with this will perfectly supersede "erofs over fscache" in a simpler way since developers (mainly containerd folks) could leverage their existing caching mechanism entirely in userspace instead of strictly following the predefined in-kernel caching tree hierarchy. After "fanotify pre-content hooks" lands upstream to provide the same functionality, "erofs over fscache" will be removed then (as an EROFS internal improvement and EROFS will not have to bother with on-demand fetching and/or caching improvements anymore.) [1] https://github.com/containers/storage/pull/2039 [2] https://lore.kernel.org/r/CAOQ4uxjbVxnubaPjVaGYiSwoGDTdpWbB=w_AeM6YM=zVixsUfQ@mail.gmail.com [3] https://docs.kernel.org/filesystems/caching/fscache.html [4] https://lore.kernel.org/r/cover.1723670362.git.josef@toxicpanda.com Closes: https://github.com/containers/composefs/issues/144 Reviewed-by: Sandeep Dhavale <dhavale@google.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240830032840.3783206-1-hsiangkao@linux.alibaba.com
* erofs: Zstandard compression supportGao Xiang2024-05-091-0/+15
| | | | | | | | | | | | | | | | | | | | | | Add Zstandard compression as the 4th supported algorithm since it becomes more popular now and some end users have asked this for quite a while [1][2]. Each EROFS physical cluster contains only one valid standard Zstandard frame as described in [3] so that decompression can be performed on a per-pcluster basis independently. Currently, it just leverages multi-call stream decompression APIs with internal sliding window buffers. One-shot or bufferless decompression could be implemented later for even better performance if needed. [1] https://github.com/erofs/erofs-utils/issues/6 [2] https://lore.kernel.org/r/Y08h+z6CZdnS1XBm@B-P7TQMD6M-0146.lan [3] https://www.rfc-editor.org/rfc/rfc8478.txt Acked-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240508234453.17896-1-xiang@kernel.org
* netfs, fscache: Combine fscache with netfsDavid Howells2023-12-241-2/+5
| | | | | | | | | | | | | Now that the fscache code is moved to be colocated with the netfslib code so that they combined into one module, do the combining. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: Christian Brauner <christian@brauner.io> cc: linux-fsdevel@vger.kernel.org cc: linux-cachefs@redhat.com cc: linux-nfs@vger.kernel.org, cc: linux-erofs@lists.ozlabs.org
* MAINTAINERS: erofs: add EROFS webpageGao Xiang2023-11-171-1/+1
| | | | | | | | | | Add a new `W:` field of the EROFS entry points to the documentation site at <https://erofs.docs.kernel.org>. In addition, update the in-tree documentation and Kconfig too. Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20231117085329.1624223-1-hsiangkao@linux.alibaba.com
* erofs: don't warn MicroLZMA format anymoreGao Xiang2023-10-311-5/+2
| | | | | | | | | | 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. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20231021020137.1646959-1-hsiangkao@linux.alibaba.com
* erofs: boost negative xattr lookup with bloom filterJingbo Xu2023-08-111-0/+1
| | | | | | | | | | | | | | | | | | | | Optimise the negative xattr lookup with bloom filter. The bit value for the bloom filter map has a reverse semantics for compatibility. That is, the bit value of 0 indicates existence, while the bit value of 1 indicates the absence of corresponding xattr. The initial version is _only_ enabled when xattr_filter_reserved is zero. The filter map internals may change in the future, in which case the reserved flag will be set non-zero and we don't need bothering the compatible bits again at that time. For now disable the optimization if this reserved flag is non-zero. Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20230722094538.11754-3-jefflexu@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
* erofs: DEFLATE compression supportGao Xiang2023-08-111-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20230810154859.118330-1-hsiangkao@linux.alibaba.com
* erofs: use HIPRI by default if per-cpu kthreads are enabledGao Xiang2023-05-231-0/+1
| | | | | | | | | | | | | | | | | | | | As Sandeep shown [1], high priority RT per-cpu kthreads are typically helpful for Android scenarios to minimize the scheduling latencies. Switch EROFS_FS_PCPU_KTHREAD_HIPRI on by default if EROFS_FS_PCPU_KTHREAD is on since it's the typical use cases for EROFS_FS_PCPU_KTHREAD. Also clean up unneeded sched_set_normal(). [1] https://lore.kernel.org/r/CAB=BE-SBtO6vcoyLNA9F-9VaN5R0t3o_Zn+FW8GbO6wyUqFneQ@mail.gmail.com Reviewed-by: Yue Hu <huyue2@coolpad.com> Reviewed-by: Sandeep Dhavale <dhavale@google.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20230522092141.124290-1-hsiangkao@linux.alibaba.com
* erofs: add per-cpu threads for decompression as an optionSandeep Dhavale2023-02-151-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using per-cpu thread pool we can reduce the scheduling latency compared to workqueue implementation. With this patch scheduling latency and variation is reduced as per-cpu threads are high priority kthread_workers. The results were evaluated on arm64 Android devices running 5.10 kernel. The table below shows resulting improvements of total scheduling latency for the same app launch benchmark runs with 50 iterations. Scheduling latency is the latency between when the task (workqueue kworker vs kthread_worker) became eligible to run to when it actually started running. +-------------------------+-----------+----------------+---------+ | | workqueue | kthread_worker | diff | +-------------------------+-----------+----------------+---------+ | Average (us) | 15253 | 2914 | -80.89% | | Median (us) | 14001 | 2912 | -79.20% | | Minimum (us) | 3117 | 1027 | -67.05% | | Maximum (us) | 30170 | 3805 | -87.39% | | Standard deviation (us) | 7166 | 359 | | +-------------------------+-----------+----------------+---------+ Background: Boot times and cold app launch benchmarks are very important to the Android ecosystem as they directly translate to responsiveness from user point of view. While EROFS provides a lot of important features like space savings, we saw some performance penalty in cold app launch benchmarks in few scenarios. Analysis showed that the significant variance was coming from the scheduling cost while decompression cost was more or less the same. Having per-cpu thread pool we can see from the above table that this variation is reduced by ~80% on average. This problem was discussed at LPC 2022. Link to LPC 2022 slides and talk at [1] [1] https://lpc.events/event/16/contributions/1338/ [ Gao Xiang: At least, we have to add this until WQ_UNBOUND workqueue issue [2] on many arm64 devices is resolved. ] [2] https://lore.kernel.org/r/CAJkfWY490-m6wNubkxiTPsW59sfsQs37Wey279LmiRxKt7aQYg@mail.gmail.com Signed-off-by: Sandeep Dhavale <dhavale@google.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20230208093322.75816-1-hsiangkao@linux.alibaba.com
* erofs: register fscache volumeJeffle Xu2022-05-181-0/+10
| | | | | | | | | | | | | | | | | A new fscache based mode is going to be introduced for erofs, in which case on-demand read semantics is implemented through fscache. As the first step, register fscache volume for each erofs filesystem. That means, data blobs can not be shared among erofs filesystems. In the following iteration, we are going to introduce the domain semantics, in which case several erofs filesystems can belong to one domain, and data blobs can be shared among these erofs filesystems of one domain. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20220425122143.56815-12-jefflexu@linux.alibaba.com Acked-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
* erofs: lzma compression supportGao Xiang2021-10-191-0/+16
| | | | | | | | | | | | | | | | | | | | | | 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>
* erofs: add multiple device supportGao Xiang2021-10-181-9/+15
| | | | | | | | | | | | | | | | | | | In order to support multi-layer container images, add multiple device feature to EROFS. Two ways are available to use for now: - Devices can be mapped into 32-bit global block address space; - Device ID can be specified with the chunk indexes format. Note that it assumes no extent would cross device boundary and mkfs should take care of it seriously. In the future, a dedicated device manager could be introduced then thus extra devices can be automatically scanned by UUID as well. Link: https://lore.kernel.org/r/20211014081010.43485-1-hsiangkao@linux.alibaba.com Reviewed-by: Chao Yu <chao@kernel.org> Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
* erofs: iomap support for non-tailpacking DIOHuang Jianan2021-08-101-0/+1
| | | | | | | | | | | | | | | | | | | Add iomap support for non-tailpacking uncompressed data in order to support DIO and DAX. Direct I/O is useful in certain scenarios for uncompressed files. For example, double pagecache can be avoid by direct I/O when loop device is used for uncompressed files containing upper layer compressed filesystem. This adds iomap DIO support for non-tailpacking cases first and tail-packing inline files are handled in the follow-up patch. Link: https://lore.kernel.org/r/20210805003601.183063-2-hsiangkao@linux.alibaba.com Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Huang Jianan <huangjianan@oppo.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
* erofs: clean up file headers & footersGao Xiang2021-06-081-1/+0
| | | | | | | | | | - 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>
* erofs: introduce physical cluster slab poolsGao Xiang2021-04-101-14/+0
| | | | | | | | | | | | | | Since multiple pcluster sizes could be used at once, the number of compressed pages will become a variable factor. It's necessary to introduce slab pools rather than a single slab cache now. This limits the pclustersize to 1M (Z_EROFS_PCLUSTER_MAX_SIZE), and get rid of the obsolete EROFS_FS_CLUSTER_PAGE_LIMIT, which has no use now. Link: https://lore.kernel.org/r/20210407043927.10623-4-xiang@kernel.org Acked-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
* erofs: support superblock checksumPratik Shinde2019-11-241-0/+1
| | | | | | | | | | | | | | Introduce superblock checksum feature in order to check at mounting time. Note that the first 1024 bytes are ignore for x86 boot sectors and other oddities. Link: https://lore.kernel.org/r/20191104024937.113939-1-gaoxiang25@huawei.com Signed-off-by: Pratik Shinde <pratikshinde320@gmail.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
* erofs: kill all erofs specific fault injectionGao Xiang2019-09-051-7/+0
| | | | | | | | | | | | As Christoph suggested [1], "Please just use plain kmalloc everywhere and let the normal kernel error injection code take care of injeting any errors." [1] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/ Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> Link: https://lore.kernel.org/r/20190904020912.63925-20-gaoxiang25@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* erofs: move erofs out of stagingGao Xiang2019-08-241-0/+98
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>