kernel/linux.git/fs/erofs/sysfs.c, branch v7.1

erofs: avoid some unnecessary #ifdefs

2026-02-03T03:25:55+00:00

They can either be removed or replaced with IS_ENABLED(). Signed-off-by: Ferry Meng Reviewed-by: Gao Xiang Signed-off-by: Gao Xiang

erofs: separate plain and compressed filesystems formally

2026-02-03T03:05:57+00:00

The EROFS on-disk format uses a tiny, plain metadata design that prioritizes performance and minimizes complex inconsistencies against common writable disk filesystems (almost all serious metadata inconsistency cannot happen in well-designed immutable filesystems like EROFS). EROFS deliberately avoids artificial design flaws to eliminate serious security risks from untrusted remote sources by design, although human-made implementation bugs can still happen sometimes. Currently, there is no strict check to prevent compressed inodes, especially LZ4-compressed inodes, from being read in plain filesystems. Starting with erofs-utils 1.0 and Linux 5.3, LZ4_0PADDING sb feature is automatically enabled for LZ4-compressed EROFS images to support in-place decompression. Furthermore, since Linux 5.4 LTS is no longer supported, we no longer need to handle ancient LZ4-compressed EROFS images generated by erofs-utils prior to 1.0. To formally distinguish different filesystem types for improved security: - Use the presence of LZ4_0PADDING or a non-zero `dsb->u1.lz4_max_distance` as a marker for compressed filesystems containing LZ4-compressed inodes only; - For other algorithms, use `dsb->u1.available_compr_algs` bitmap. Note: LZ4_0PADDING has been supported since Linux 5.4 (the first formal kernel version), so exposing it via sysfs is no longer necessary and is now deprecated (but remain it for five more years until 2031): `dsb->u1` has been strictly non-zero for all EROFS images containing compressed inodes starting with erofs-utils v1.3 and it is actually a much better marker for compressed filesystems. Signed-off-by: Gao Xiang

erofs: tidy up synchronous decompression

2026-01-22T16:05:11+00:00

- Get rid of `sbi->opt.max_sync_decompress_pages` since it's fixed as 3 all the time; - Add Z_EROFS_MAX_SYNC_DECOMPRESS_BYTES in bytes instead of in pages, since for non-4K pages, 3-page limitation makes no sense; - Move `sync_decompress` to sbi to avoid unexpected remount impact; - Fold z_erofs_is_sync_decompress() into its caller; - Better description of sysfs entry `sync_decompress`. Reviewed-by: Chao Yu Signed-off-by: Gao Xiang

erofs: support to readahead dirent blocks in erofs_readdir()

2025-07-24T11:44:08+00:00

This patch supports to readahead more blocks in erofs_readdir(), it can enhance readdir performance in large direcotry. readdir test in a large directory which contains 12000 sub-files. files_per_second Before: 926385.54 After: 2380435.562 Meanwhile, let's introduces a new sysfs entry to control readahead bytes to provide more flexible policy for readahead of readdir(). - location: /sys/fs/erofs//dir_ra_bytes - default value: 16384 - disable readahead: set the value to 0 Signed-off-by: Chao Yu Reviewed-by: Gao Xiang Link: https://lore.kernel.org/r/20250721021352.2495371-1-chao@kernel.org [ Gao Xiang: minor styling adjustment. ] Signed-off-by: Gao Xiang

erofs: implement metadata compression

2025-07-24T11:43:31+00:00

Thanks to the meta buffer infrastructure, metadata-compressed inodes are just read from the metabox inode instead of the blockdevice (or backing file) inode. The same is true for shared extended attributes. When metadata compression is enabled, inode numbers are divided from on-disk NIDs because of non-LTS 32-bit application compatibility. Co-developed-by: Gao Xiang Signed-off-by: Bo Liu (OpenAnolis) Acked-by: Chao Yu Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20250722003229.2121752-1-hsiangkao@linux.alibaba.com

erofs: support DEFLATE decompression by using Intel QAT

2025-05-25T07:27:40+00:00

This patch introduces the use of the Intel QAT to offload EROFS data decompression, aiming to improve the decompression performance. A 285MiB dataset is used with the following command to create EROFS images with different cluster sizes: $ mkfs.erofs -zdeflate,level=9 -C{4096,16384,65536,131072,262144} Fio is used to test the following read patterns: $ fio -filename=testfile -bs=4k -rw=read -name=job1 $ fio -filename=testfile -bs=4k -rw=randread -name=job1 $ fio -filename=testfile -bs=4k -rw=randread --io_size=14m -name=job1 Here are some performance numbers for reference: Processors: Intel(R) Xeon(R) 6766E (144 cores) Memory: 512 GiB |-----------------------------------------------------------------------------| | | Cluster size | sequential read | randread | small randread(5%) | |-----------|--------------|-----------------|-----------|--------------------| | Intel QAT | 4096 | 538 MiB/s | 112 MiB/s | 20.76 MiB/s | | Intel QAT | 16384 | 699 MiB/s | 158 MiB/s | 21.02 MiB/s | | Intel QAT | 65536 | 917 MiB/s | 278 MiB/s | 20.90 MiB/s | | Intel QAT | 131072 | 1056 MiB/s | 351 MiB/s | 23.36 MiB/s | | Intel QAT | 262144 | 1145 MiB/s | 431 MiB/s | 26.66 MiB/s | | deflate | 4096 | 499 MiB/s | 108 MiB/s | 21.50 MiB/s | | deflate | 16384 | 422 MiB/s | 125 MiB/s | 18.94 MiB/s | | deflate | 65536 | 452 MiB/s | 159 MiB/s | 13.02 MiB/s | | deflate | 131072 | 452 MiB/s | 177 MiB/s | 11.44 MiB/s | | deflate | 262144 | 466 MiB/s | 194 MiB/s | 10.60 MiB/s | Signed-off-by: Bo Liu Reviewed-by: Gao Xiang Link: https://lore.kernel.org/r/20250522094931.28956-1-liubo03@inspur.com [ Gao Xiang: refine the commit message. ] Signed-off-by: Gao Xiang

erofs: clean up erofs_{init,exit}_sysfs()

2025-05-22T23:51:14+00:00

Get rid of useless `goto`s. No logic changes. Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20250522084953.412096-1-hsiangkao@linux.alibaba.com

erofs: implement 48-bit block addressing for unencoded inodes

2025-03-16T17:25:26+00:00

It adapts the on-disk changes from the previous commit. It also supports EROFS_NULL_ADDR (all 1's) for EROFS_INODE_FLAT_PLAIN inodes to indicate 0-filled inodes, as it's common for composefs use cases. As a result, EROFS_INODE_CHUNK_BASED is no longer needed. Signed-off-by: Gao Xiang Acked-by: Chao Yu Link: https://lore.kernel.org/r/20250310095459.2620647-5-hsiangkao@linux.alibaba.com

erofs: add sysfs node to drop internal caches

2024-11-18T10:50:13+00:00

Add a sysfs node to drop compression-related caches, currently used to drop in-memory pclusters and cached compressed folios. Signed-off-by: Chunhai Guo Reviewed-by: Gao Xiang Link: https://lore.kernel.org/r/20241113041148.749129-1-guochunhai@vivo.com Signed-off-by: Gao Xiang

erofs: clean up erofs_register_sysfs()

2024-09-09T16:46:34+00:00

After commit 684b290abc77 ("erofs: add support for FS_IOC_GETFSSYSFSPATH"), `sb->s_sysfs_name` is now valid. Just use it to get rid of duplicated logic. Reviewed-by: Sandeep Dhavale Reviewed-by: Chao Yu Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20240828095232.571946-1-hsiangkao@linux.alibaba.com