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Commit 850be2e6 authored by Gao Xiang's avatar Gao Xiang Committed by Gao Xiang
Browse files

erofs: add big physical cluster definition 

Big pcluster indicates the size of compressed data for each physical
pcluster is no longer fixed as block size, but could be more than 1
block (more accurately, 1 logical pcluster)

When big pcluster feature is enabled for head0/1, delta0 of the 1st
non-head lcluster index will keep block count of this pcluster in
lcluster size instead of 1. Or, the compressed size of pcluster
should be 1 lcluster if pcluster has no non-head lcluster index.

Also note that BIG_PCLUSTER feature reuses COMPR_CFGS feature since
it depends on COMPR_CFGS and will be released together.

Link: https://lore.kernel.org/r/20210407043927.10623-6-xiang@kernel.org


Acked-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarGao Xiang <hsiangkao@redhat.com>
parent 57a75ccc

fs/erofs/erofs_fs.h

+15 −4
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
 */

#define EROFS_FEATURE_INCOMPAT_LZ4_0PADDING	0x00000001

#define EROFS_FEATURE_INCOMPAT_COMPR_CFGS	0x00000002

#define EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER	0x00000002

#define EROFS_ALL_FEATURE_INCOMPAT		EROFS_FEATURE_INCOMPAT_LZ4_0PADDING



#define EROFS_SB_EXTSLOT_SIZE	16
@@ -214,17 +215,20 @@ enum { 
/* 14 bytes (+ length field = 16 bytes) */

struct z_erofs_lz4_cfgs {

	__le16 max_distance;

	u8 reserved[12];

	__le16 max_pclusterblks;

	u8 reserved[10];

} __packed;



/*

 * bit 0 : COMPACTED_2B indexes (0 - off; 1 - on)

 *  e.g. for 4k logical cluster size,      4B        if compacted 2B is off;

 *                                  (4B) + 2B + (4B) if compacted 2B is on.

 * bit 1 : HEAD1 big pcluster (0 - off; 1 - on)

 * bit 2 : HEAD2 big pcluster (0 - off; 1 - on)

 */

#define Z_EROFS_ADVISE_COMPACTED_2B_BIT         0



#define Z_EROFS_ADVISE_COMPACTED_2B     (1 << Z_EROFS_ADVISE_COMPACTED_2B_BIT)

#define Z_EROFS_ADVISE_COMPACTED_2B		0x0001

#define Z_EROFS_ADVISE_BIG_PCLUSTER_1		0x0002

#define Z_EROFS_ADVISE_BIG_PCLUSTER_2		0x0004



struct z_erofs_map_header {

	__le32	h_reserved1;
@@ -279,6 +283,13 @@ enum { 
#define Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS        2

#define Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT         0



/*

 * D0_CBLKCNT will be marked _only_ at the 1st non-head lcluster to store the

 * compressed block count of a compressed extent (in logical clusters, aka.

 * block count of a pcluster).

 */

#define Z_EROFS_VLE_DI_D0_CBLKCNT		(1 << 11)



struct z_erofs_vle_decompressed_index {

	__le16 di_advise;

	/* where to decompress in the head cluster */

fs/erofs/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -225,6 +225,7 @@ static inline bool erofs_sb_has_##name(struct erofs_sb_info *sbi) \ 


EROFS_FEATURE_FUNCS(lz4_0padding, incompat, INCOMPAT_LZ4_0PADDING)

EROFS_FEATURE_FUNCS(compr_cfgs, incompat, INCOMPAT_COMPR_CFGS)

EROFS_FEATURE_FUNCS(big_pcluster, incompat, INCOMPAT_BIG_PCLUSTER)

EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)



/* atomic flag definitions */