Messages in this thread | | | From | Gao Xiang <> | Subject | [PATCH v2 0/4] erofs: introduce on-disk compression configurations | Date | Mon, 29 Mar 2021 09:23:04 +0800 |
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From: Gao Xiang <hsiangkao@redhat.com>
Hi folks,
When we provides support for different algorithms or big pcluster, it'd be necessary to record some configuration in the per-fs basis.
For example, when big pcluster feature for lz4 is enabled, we need to know the largest pclustersize in the whole fs instance to adjust per-CPU buffers in advance, which will be used to handle in-place decompression failure for inplace IO then. And we also need to record global arguments (e.g. dict_size) for the upcoming LZMA algorithm support.
Therefore, this patchset introduces a new INCOMPAT feature called COMPR_CFGS, which provides an available algorithm bitmap in the sb and a variable array list to store corresponding arguments for each available algorithms.
Since such a INCOMPAT sb feature will be introduced, it'd be better to reuse such bit for BIGPCLUSTER feature as well since BIGPCLUSTER feature depends on COMPR_CFGS and will be released together with COMPR_CFGS.
If COMPR_CFGS is disabled, the field of available algorithm bitmap would become a lz4_max_distance (which is now reserved as 0), and max_distance can be safely ignored for old kernels since 64k lz4 dictionary is always enough even new images could reduce the sliding window.
Thanks, Gao Xiang
Changes since v1: - [2/4] add a comment on lz4_max_distance (Chao); - [4/4] fix a misplaced label (Chao); - [4/4] enable COMPR_CFGS with BIG_PCLUSTER later since they share the same bit.
Gao Xiang (3): erofs: introduce erofs_sb_has_xxx() helpers erofs: introduce on-disk lz4 fs configurations erofs: add on-disk compression configurations
Huang Jianan (1): erofs: support adjust lz4 history window size
fs/erofs/decompressor.c | 35 ++++++++-- fs/erofs/erofs_fs.h | 20 +++++- fs/erofs/internal.h | 33 +++++++++ fs/erofs/super.c | 147 +++++++++++++++++++++++++++++++++++++++- 4 files changed, 224 insertions(+), 11 deletions(-)
-- 2.20.1
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