kernel/linux.git/fs/squashfs/block.c, branch v6.6.134

squashfs: squashfs_read_data need to check if the length is 0

2024-08-19T04:04:26+00:00

[ Upstream commit eb66b8abae98f869c224f7c852b685ae02144564 ] When the length passed in is 0, the pagemap_scan_test_walk() caller should bail. This error causes at least a WARN_ON(). Link: https://lkml.kernel.org/r/20231116031352.40853-1-lizhi.xu@windriver.com Reported-by: syzbot+32d3767580a1ea339a81@syzkaller.appspotmail.com Closes: https://lkml.kernel.org/r/0000000000000526f2060a30a085@google.com Signed-off-by: Lizhi Xu Reviewed-by: Phillip Lougher Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

squashfs: fix cache race with migration

2023-07-08T16:29:30+00:00

Migration replaces the page in the mapping before copying the contents and the flags over from the old page, so check that the page in the page cache is really up to date before using it. Without this, stressing squashfs reads with parallel compaction sometimes results in squashfs reporting data corruption. Link: https://lkml.kernel.org/r/20230629-squashfs-cache-migration-v1-1-d50ebe55099d@axis.com Fixes: e994f5b677ee ("squashfs: cache partial compressed blocks") Signed-off-by: Vincent Whitchurch Cc: Christoph Hellwig Cc: Phillip Lougher Signed-off-by: Andrew Morton

squashfs: cache partial compressed blocks

2023-06-10T00:44:14+00:00

Before commit 93e72b3c612adcaca1 ("squashfs: migrate from ll_rw_block usage to BIO"), compressed blocks read by squashfs were cached in the page cache, but that is not the case after that commit. That has lead to squashfs having to re-read a lot of sectors from disk/flash. For example, the first sectors of every metadata block need to be read twice from the disk. Once partially to read the length, and a second time to read the block itself. Also, in linear reads of large files, the last sectors of one data block are re-read from disk when reading the next data block, since the compressed blocks are of variable sizes and not aligned to device blocks. This extra I/O results in a degrade in read performance of, for example, ~16% in one scenario on my ARM platform using squashfs with dm-verity and NAND. Since the decompressed data is cached in the page cache or squashfs' internal metadata and fragment caches, caching _all_ compressed pages would lead to a lot of double caching and is undesirable. But make the code cache any disk blocks which were only partially requested, since these are the ones likely to include data which is needed by other file system blocks. This restores read performance in my test scenario. The compressed block caching is only applied when the disk block size is equal to the page size, to avoid having to deal with caching sub-page reads. [akpm@linux-foundation.org: fs/squashfs/block.c needs linux/pagemap.h] [vincent.whitchurch@axis.com: fix page update race] Link: https://lkml.kernel.org/r/20230526-squashfs-cache-fixup-v1-1-d54a7fa23e7b@axis.com [vincent.whitchurch@axis.com: fix page indices] Link: https://lkml.kernel.org/r/20230526-squashfs-cache-fixup-v1-2-d54a7fa23e7b@axis.com [akpm@linux-foundation.org: fix layout, per hch] Link: https://lkml.kernel.org/r/20230510-squashfs-cache-v4-1-3bd394e1ee71@axis.com Signed-off-by: Vincent Whitchurch Reviewed-by: Christoph Hellwig Reviewed-by: Phillip Lougher Signed-off-by: Andrew Morton

squashfs: don't include buffer_head.h

2023-06-10T00:44:14+00:00

Squashfs has stopped using buffers heads in 93e72b3c612adcaca1 ("squashfs: migrate from ll_rw_block usage to BIO"). Link: https://lkml.kernel.org/r/20230517071622.245151-1-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Pankaj Raghav Reviewed-by: Phillip Lougher Signed-off-by: Andrew Morton

squashfs: add the mount parameter theads=

2022-11-18T21:55:08+00:00

Patch series 'squashfs: Add the mount parameter "threads="'. Currently, Squashfs supports multiple decompressor parallel modes. However, this mode can be configured only during kernel building and does not support flexible selection during runtime. In the current patch set, the mount parameter "threads=" is added to allow users to select the parallel decompressor mode and configure the number of decompressors when mounting a file system. "threads=" The upper limit is num_online_cpus() * 2. This patch (of 2): Squashfs supports three decompression concurrency modes: Single-thread mode: concurrent reads are blocked and the memory overhead is small. Multi-thread mode/percpu mode: reduces concurrent read blocking but increases memory overhead. The corresponding schema must be fixed at compile time. During mounting, the concurrent decompression mode cannot be adjusted based on file read blocking. The mount parameter theads= is added to select the concurrent decompression mode of a single SquashFS file system image. Link: https://lkml.kernel.org/r/20221019030930.130456-1-nixiaoming@huawei.com Link: https://lkml.kernel.org/r/20221019030930.130456-2-nixiaoming@huawei.com Signed-off-by: Xiaoming Ni Reviewed-by: Phillip Lougher Cc: Jianguo Chen Cc: Jubin Zhong Cc: Zhang Yi Signed-off-by: Andrew Morton

squashfs: extend "page actor" to handle missing pages

2022-06-17T02:58:21+00:00

Patch series "Squashfs: handle missing pages decompressing into page cache". This patchset enables Squashfs to handle missing pages when directly decompressing datablocks into the page cache. Previously if the full set of pages needed was not available, Squashfs would have to fall back to using an intermediate buffer (the older method), which is slower, involving a memcopy, and it introduces contention on a shared buffer. The first patch extends the "page actor" code to handle missing pages. The second patch updates Squashfs_readpage_block() to use the new functionality, and removes the code that falls back to using an intermediate buffer. This patchset is independent of the readahead work, and it is standalone. It can be merged on its own. But the readahead patch for efficiency also needs this patch-set. This patch (of 2): This patch extends the "page actor" code to handle missing pages. Previously if the full set of pages needed to decompress a Squashfs datablock was unavailable, this would cause decompression to fail on the missing pages. In this case direct decompression into the page cache could not be achieved and the code would fall back to using the older intermediate buffer method. With this patch, direct decompression into the page cache can be achieved with missing pages. For "multi-shot" decompressors (zlib, xz, zstd), the page actor will allocate a temporary buffer which is passed to the decompressor, and then freed by the page actor. For "single shot" decompressors (lz4, lzo) which decompress into a contiguous "bounce buffer", and which is then copied into the page cache, it would be pointless to allocate a temporary buffer, memcpy into it, and then free it. For these decompressors -ENOMEM is returned, which signifies that the memcpy for that page should be skipped. This also happens if the data block is uncompressed. Link: https://lkml.kernel.org/r/20220611032133.5743-1-phillip@squashfs.org.uk Link: https://lkml.kernel.org/r/20220611032133.5743-2-phillip@squashfs.org.uk Signed-off-by: Phillip Lougher Cc: Matthew Wilcox (Oracle) Cc: Hsin-Yi Wang Cc: Xiongwei Song Signed-off-by: Andrew Morton

block: turn bio_kmalloc into a simple kmalloc wrapper

2022-04-18T01:30:41+00:00

Remove the magic autofree semantics and require the callers to explicitly call bio_init to initialize the bio. This allows bio_free to catch accidental bio_put calls on bio_init()ed bios as well. Signed-off-by: Christoph Hellwig Acked-by: Coly Li Acked-by: Mike Snitzer Link: https://lore.kernel.org/r/20220406061228.410163-5-hch@lst.de Signed-off-by: Jens Axboe

squashfs: always use bio_kmalloc in squashfs_bio_read

2022-04-18T01:29:41+00:00

If a plain kmalloc that is not backed by a mempool is safe here for a large read (and the actual page allocations), it must also be for a small one, so simplify the code a bit. Signed-off-by: Christoph Hellwig Acked-by: Phillip Lougher Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20220406061228.410163-3-hch@lst.de Signed-off-by: Jens Axboe

block: pass a block_device and opf to bio_alloc

2022-02-02T14:49:59+00:00

Pass the block_device and operation that we plan to use this bio for to bio_alloc to optimize the assignment. NULL/0 can be passed, both for the passthrough case on a raw request_queue and to temporarily avoid refactoring some nasty code. Also move the gfp_mask argument after the nr_vecs argument for a much more logical calling convention matching what most of the kernel does. Signed-off-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20220124091107.642561-18-hch@lst.de Signed-off-by: Jens Axboe

squashfs: use bvec_virt

2021-08-16T16:50:32+00:00

Use bvec_virt instead of open coding it. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20210804095634.460779-7-hch@lst.de Signed-off-by: Jens Axboe