erofs: Zstandard compression support
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
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index d2fe813..9d85b6c 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -399,6 +399,13 @@ const struct z_erofs_decompressor erofs_decompressors[] = {
.name = "deflate"
},
#endif
+#ifdef CONFIG_EROFS_FS_ZIP_ZSTD
+ [Z_EROFS_COMPRESSION_ZSTD] = {
+ .config = z_erofs_load_zstd_config,
+ .decompress = z_erofs_zstd_decompress,
+ .name = "zstd"
+ },
+#endif
};
int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb)
