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erofs: introduce on-disk lz4 fs configurations

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Introduce z_erofs_lz4_cfgs to store all lz4 configurations.
Currently it's only max_distance, but will be used for new
features later.

Link: https://lore.kernel.org/r/20210329012308.28743-4-hsiangkao@aol.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
This commit is contained in:
Gao Xiang 2021-03-29 09:23:07 +08:00
parent 5d50538fc5
commit 46249cded1
4 changed files with 25 additions and 6 deletions
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15
fs/erofs/decompressor.c
View File

@ -29,9 +29,20 @@ struct z_erofs_decompressor {
};
int z_erofs_load_lz4_config(struct super_block *sb,
struct erofs_super_block *dsb)
struct erofs_super_block *dsb,
struct z_erofs_lz4_cfgs *lz4, int size)
{
u16 distance = le16_to_cpu(dsb->lz4_max_distance);
u16 distance;
if (lz4) {
if (size < sizeof(struct z_erofs_lz4_cfgs)) {
erofs_err(sb, "invalid lz4 cfgs, size=%u", size);
return -EINVAL;
}
distance = le16_to_cpu(lz4->max_distance);
} else {
distance = le16_to_cpu(dsb->lz4_max_distance);
}
EROFS_SB(sb)->lz4.max_distance_pages = distance ?
DIV_ROUND_UP(distance, PAGE_SIZE) + 1 :

6
fs/erofs/erofs_fs.h
View File

@ -200,6 +200,12 @@ enum {
Z_EROFS_COMPRESSION_MAX
};
/* 14 bytes (+ length field = 16 bytes) */
struct z_erofs_lz4_cfgs {
__le16 max_distance;
u8 reserved[12];
} __packed;
/*
* bit 0 : COMPACTED_2B indexes (0 - off; 1 - on)
* e.g. for 4k logical cluster size, 4B if compacted 2B is off;

8
fs/erofs/internal.h
View File

@ -439,7 +439,8 @@ int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi,
int erofs_try_to_free_cached_page(struct address_space *mapping,
struct page *page);
int z_erofs_load_lz4_config(struct super_block *sb,
struct erofs_super_block *dsb);
struct erofs_super_block *dsb,
struct z_erofs_lz4_cfgs *lz4, int len);
#else
static inline void erofs_shrinker_register(struct super_block *sb) {}
static inline void erofs_shrinker_unregister(struct super_block *sb) {}
@ -448,9 +449,10 @@ static inline void erofs_exit_shrinker(void) {}
static inline int z_erofs_init_zip_subsystem(void) { return 0; }
static inline void z_erofs_exit_zip_subsystem(void) {}
static inline int z_erofs_load_lz4_config(struct super_block *sb,
struct erofs_super_block *dsb)
struct erofs_super_block *dsb,
struct z_erofs_lz4_cfgs *lz4, int len)
{
if (dsb->lz4_max_distance) {
if (lz4 || dsb->lz4_max_distance) {
erofs_err(sb, "lz4 algorithm isn't enabled");
return -EINVAL;
}

2
fs/erofs/super.c
View File

@ -189,7 +189,7 @@ static int erofs_read_superblock(struct super_block *sb)
}
/* parse on-disk compression configurations */
ret = z_erofs_load_lz4_config(sb, dsb);
ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0);
out:
kunmap(page);
put_page(page);