kernel/linux.git/fs/erofs/utils.c, branch v6.6.131

erofs: fix erofs_insert_workgroup() lockref usage

2023-11-20T10:59:23+00:00

[ Upstream commit 1a0ac8bd7a4fa5b2f4ef14c3b1e9d6e5a5faae06 ] As Linus pointed out [1], lockref_put_return() is fundamentally designed to be something that can fail. It behaves as a fastpath-only thing, and the failure case needs to be handled anyway. Actually, since the new pcluster was just allocated without being populated, it won't be accessed by others until it is inserted into XArray, so lockref helpers are actually unneeded here. Let's just set the proper reference count on initializing. [1] https://lore.kernel.org/r/CAHk-=whCga8BeQnJ3ZBh_Hfm9ctba_wpF444LpwRybVNMzO6Dw@mail.gmail.com Fixes: 7674a42f35ea ("erofs: use struct lockref to replace handcrafted approach") Reviewed-by: Chao Yu Link: https://lore.kernel.org/r/20231031060524.1103921-1-hsiangkao@linux.alibaba.com Signed-off-by: Gao Xiang Signed-off-by: Sasha Levin

erofs: use struct lockref to replace handcrafted approach

2023-06-18T04:10:47+00:00

Let's avoid the current handcrafted lockref although `struct lockref` inclusion usually increases extra 4 bytes with an explicit spinlock if CONFIG_DEBUG_SPINLOCK is off. Apart from the size difference, note that the meaning of refcount is also changed to active users. IOWs, it doesn't take an extra refcount for XArray tree insertion. I don't observe any significant performance difference at least on our cloud compute server but the new one indeed simplifies the overall codebase a bit. Signed-off-by: Gao Xiang Reviewed-by: Yue Hu Link: https://lore.kernel.org/r/20230529123727.79943-1-hsiangkao@linux.alibaba.com

mm: shrinkers: provide shrinkers with names

2022-07-04T01:08:40+00:00

Currently shrinkers are anonymous objects. For debugging purposes they can be identified by count/scan function names, but it's not always useful: e.g. for superblock's shrinkers it's nice to have at least an idea of to which superblock the shrinker belongs. This commit adds names to shrinkers. register_shrinker() and prealloc_shrinker() functions are extended to take a format and arguments to master a name. In some cases it's not possible to determine a good name at the time when a shrinker is allocated. For such cases shrinker_debugfs_rename() is provided. The expected format is: -[:]- For some shrinkers an instance can be encoded as (MAJOR:MINOR) pair. After this change the shrinker debugfs directory looks like: $ cd /sys/kernel/debug/shrinker/ $ ls dquota-cache-16 sb-devpts-28 sb-proc-47 sb-tmpfs-42 mm-shadow-18 sb-devtmpfs-5 sb-proc-48 sb-tmpfs-43 mm-zspool:zram0-34 sb-hugetlbfs-17 sb-pstore-31 sb-tmpfs-44 rcu-kfree-0 sb-hugetlbfs-33 sb-rootfs-2 sb-tmpfs-49 sb-aio-20 sb-iomem-12 sb-securityfs-6 sb-tracefs-13 sb-anon_inodefs-15 sb-mqueue-21 sb-selinuxfs-22 sb-xfs:vda1-36 sb-bdev-3 sb-nsfs-4 sb-sockfs-8 sb-zsmalloc-19 sb-bpf-32 sb-pipefs-14 sb-sysfs-26 thp-deferred_split-10 sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-1 thp-zero-9 sb-cgroup2-30 sb-proc-39 sb-tmpfs-27 xfs-buf:vda1-37 sb-configfs-23 sb-proc-41 sb-tmpfs-29 xfs-inodegc:vda1-38 sb-dax-11 sb-proc-45 sb-tmpfs-35 sb-debugfs-7 sb-proc-46 sb-tmpfs-40 [roman.gushchin@linux.dev: fix build warnings] Link: https://lkml.kernel.org/r/Yr+ZTnLb9lJk6fJO@castle Reported-by: kernel test robot Link: https://lkml.kernel.org/r/20220601032227.4076670-4-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin Cc: Christophe JAILLET Cc: Dave Chinner Cc: Hillf Danton Cc: Kent Overstreet Cc: Muchun Song Signed-off-by: Andrew Morton

erofs: fix deadlock when shrink erofs slab

2021-11-23T06:58:16+00:00

We observed the following deadlock in the stress test under low memory scenario: Thread A Thread B - erofs_shrink_scan - erofs_try_to_release_workgroup - erofs_workgroup_try_to_freeze -- A - z_erofs_do_read_page - z_erofs_collection_begin - z_erofs_register_collection - erofs_insert_workgroup - xa_lock(&sbi->managed_pslots) -- B - erofs_workgroup_get - erofs_wait_on_workgroup_freezed -- A - xa_erase - xa_lock(&sbi->managed_pslots) -- B To fix this, it needs to hold xa_lock before freezing the workgroup since xarray will be touched then. So let's hold the lock before accessing each workgroup, just like what we did with the radix tree before. [ Gao Xiang: Jianhua Hao also reports this issue at https://lore.kernel.org/r/b10b85df30694bac8aadfe43537c897a@xiaomi.com ] Link: https://lore.kernel.org/r/20211118135844.3559-1-huangjianan@oppo.com Fixes: 64094a04414f ("erofs: convert workstn to XArray") Reviewed-by: Chao Yu Reviewed-by: Gao Xiang Signed-off-by: Huang Jianan Reported-by: Jianhua Hao Signed-off-by: Gao Xiang

erofs: get rid of ->lru usage

2021-10-25T00:22:59+00:00

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 Reviewed-by: Kent Overstreet Reviewed-by: Chao Yu Signed-off-by: Gao Xiang

erofs: clean up file headers & footers

2021-06-07T16:41:24+00:00

- 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 Signed-off-by: Gao Xiang

erofs: introduce multipage per-CPU buffers

2021-04-09T19:19:59+00:00

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 Signed-off-by: Gao Xiang

erofs: fold in used-once helper erofs_workgroup_unfreeze_final()

2020-08-03T13:04:46+00:00

It's expected that erofs_workgroup_unfreeze_final() won't be used in other places. Let's fold it to simplify the code. Link: https://lore.kernel.org/r/20200729180235.25443-1-hsiangkao@redhat.com Reviewed-by: Chao Yu Signed-off-by: Gao Xiang

erofs: Replace HTTP links with HTTPS ones

2020-08-03T13:04:29+00:00

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 Reviewed-by: Chao Yu Signed-off-by: Alexander A. Klimov Link: https://lore.kernel.org/r/20200713130944.34419-1-grandmaster@al2klimov.de Signed-off-by: Gao Xiang

erofs: correct the remaining shrink objects

2020-03-03T15:39:29+00:00

The remaining count should not include successful shrink attempts. Fixes: e7e9a307be9d ("staging: erofs: introduce workstation for decompression") Cc: # 4.19+ Link: https://lore.kernel.org/r/20200226081008.86348-1-gaoxiang25@huawei.com Reviewed-by: Chao Yu Signed-off-by: Gao Xiang