Commit ec8c2442 authored by Gao Xiang's avatar Gao Xiang Committed by Greg Kroah-Hartman
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staging: erofs: add compacted ondisk compression indexes 



This patch introduces new compacted compression indexes.

In contract to legacy compression indexes that
   each 4k logical cluster has an 8-byte index,
compacted ondisk compression indexes will have
   amortized 2 bytes for each 4k logical cluster (compacted 2B)
   amortized 4 bytes for each 4k logical cluster (compacted 4B)

In detail, several continuous clusters will be encoded in
a compacted pack with cluster types, offsets, and one blkaddr
at the end of the pack to leave 4-byte margin for better
decoding performance, as illustrated below:
   _____________________________________________
  |___@_____ encoded bits __________|_ blkaddr _|
  0       .                                     amortized * vcnt
  .          .
  .             .                   amortized * vcnt - 4
  .                .
  .___________________.
  |_type_|_clusterofs_|

Note that compacted 2 / 4B should be aligned with 32 / 8 bytes
in order to avoid each pack crossing page boundary.

Reviewed-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarGao Xiang <gaoxiang25@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e3647214

drivers/staging/erofs/data.c

+2 −2
Original line number Diff line number Diff line
@@ -124,7 +124,7 @@ static int erofs_map_blocks_flatmode(struct inode *inode, 
	trace_erofs_map_blocks_flatmode_enter(inode, map, flags);



	nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);

	lastblk = nblocks - is_inode_layout_inline(inode);

	lastblk = nblocks - is_inode_flat_inline(inode);



	if (unlikely(offset >= inode->i_size)) {

		/* leave out-of-bound access unmapped */
@@ -139,7 +139,7 @@ static int erofs_map_blocks_flatmode(struct inode *inode, 
	if (offset < blknr_to_addr(lastblk)) {

		map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la;

		map->m_plen = blknr_to_addr(lastblk) - offset;

	} else if (is_inode_layout_inline(inode)) {

	} else if (is_inode_flat_inline(inode)) {

		/* 2 - inode inline B: inode, [xattrs], inline last blk... */

		struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);

drivers/staging/erofs/erofs_fs.h

+52 −13
Original line number Diff line number Diff line
@@ -49,19 +49,29 @@ struct erofs_super_block { 
 * erofs inode data mapping:

 * 0 - inode plain without inline data A:

 * inode, [xattrs], ... | ... | no-holed data

 * 1 - inode VLE compression B:

 * 1 - inode VLE compression B (legacy):

 * inode, [xattrs], extents ... | ...

 * 2 - inode plain with inline data C:

 * inode, [xattrs], last_inline_data, ... | ... | no-holed data

 * 3~7 - reserved

 * 3 - inode compression D:

 * inode, [xattrs], map_header, extents ... | ...

 * 4~7 - reserved

 */

enum {

	EROFS_INODE_LAYOUT_PLAIN,

	EROFS_INODE_LAYOUT_COMPRESSION,

	EROFS_INODE_LAYOUT_INLINE,

	EROFS_INODE_FLAT_PLAIN,

	EROFS_INODE_FLAT_COMPRESSION_LEGACY,

	EROFS_INODE_FLAT_INLINE,

	EROFS_INODE_FLAT_COMPRESSION,

	EROFS_INODE_LAYOUT_MAX

};



static bool erofs_inode_is_data_compressed(unsigned int datamode)

{

	if (datamode == EROFS_INODE_FLAT_COMPRESSION)

		return true;

	return datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;

}



/* bit definitions of inode i_advise */

#define EROFS_I_VERSION_BITS            1

#define EROFS_I_DATA_MAPPING_BITS       3
@@ -176,11 +186,39 @@ struct erofs_xattr_entry { 
	sizeof(struct erofs_xattr_entry) + \

	(entry)->e_name_len + le16_to_cpu((entry)->e_value_size))



/* have to be aligned with 8 bytes on disk */

struct erofs_extent_header {

	__le32 eh_checksum;

	__le32 eh_reserved[3];

} __packed;

/* available compression algorithm types */

enum {

	Z_EROFS_COMPRESSION_LZ4,

	Z_EROFS_COMPRESSION_MAX

};



/*

 * 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.

 */

#define Z_EROFS_ADVISE_COMPACTED_2B_BIT         0



#define Z_EROFS_ADVISE_COMPACTED_2B     (1 << Z_EROFS_ADVISE_COMPACTED_2B_BIT)



struct z_erofs_map_header {

	__le32	h_reserved1;

	__le16	h_advise;

	/*

	 * bit 0-3 : algorithm type of head 1 (logical cluster type 01);

	 * bit 4-7 : algorithm type of head 2 (logical cluster type 11).

	 */

	__u8	h_algorithmtype;

	/*

	 * bit 0-2 : logical cluster bits - 12, e.g. 0 for 4096;

	 * bit 3-4 : (physical - logical) cluster bits of head 1:

	 *       For example, if logical clustersize = 4096, 1 for 8192.

	 * bit 5-7 : (physical - logical) cluster bits of head 2.

	 */

	__u8	h_clusterbits;

};



#define Z_EROFS_VLE_LEGACY_HEADER_PADDING       8



/*

 * Z_EROFS Variable-sized Logical Extent cluster type:
@@ -236,8 +274,9 @@ struct z_erofs_vle_decompressed_index { 
	} di_u __packed;		/* 8 bytes */

} __packed;



#define Z_EROFS_VLE_EXTENT_ALIGN(size) round_up(size, \

	sizeof(struct z_erofs_vle_decompressed_index))

#define Z_EROFS_VLE_LEGACY_INDEX_ALIGN(size) \

	(round_up(size, sizeof(struct z_erofs_vle_decompressed_index)) + \

	 sizeof(struct z_erofs_map_header) + Z_EROFS_VLE_LEGACY_HEADER_PADDING)



/* dirent sorts in alphabet order, thus we can do binary search */

struct erofs_dirent {
@@ -270,7 +309,7 @@ static inline void erofs_check_ondisk_layout_definitions(void) 
	BUILD_BUG_ON(sizeof(struct erofs_inode_v2) != 64);

	BUILD_BUG_ON(sizeof(struct erofs_xattr_ibody_header) != 12);

	BUILD_BUG_ON(sizeof(struct erofs_xattr_entry) != 4);

	BUILD_BUG_ON(sizeof(struct erofs_extent_header) != 16);

	BUILD_BUG_ON(sizeof(struct z_erofs_map_header) != 8);

	BUILD_BUG_ON(sizeof(struct z_erofs_vle_decompressed_index) != 8);

	BUILD_BUG_ON(sizeof(struct erofs_dirent) != 12);

drivers/staging/erofs/inode.c

+1 −4
Original line number Diff line number Diff line
@@ -127,12 +127,9 @@ static int fill_inline_data(struct inode *inode, void *data, 
{

	struct erofs_vnode *vi = EROFS_V(inode);

	struct erofs_sb_info *sbi = EROFS_I_SB(inode);

	const int mode = vi->datamode;



	DBG_BUGON(mode >= EROFS_INODE_LAYOUT_MAX);



	/* should be inode inline C */

	if (mode != EROFS_INODE_LAYOUT_INLINE)

	if (!is_inode_flat_inline(inode))

		return 0;



	/* fast symlink (following ext4) */

drivers/staging/erofs/internal.h

+3 −8
Original line number Diff line number Diff line
@@ -382,19 +382,14 @@ static inline unsigned long inode_datablocks(struct inode *inode) 
	return DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);

}



static inline bool is_inode_layout_plain(struct inode *inode)

{

	return EROFS_V(inode)->datamode == EROFS_INODE_LAYOUT_PLAIN;

}



static inline bool is_inode_layout_compression(struct inode *inode)

{

	return EROFS_V(inode)->datamode == EROFS_INODE_LAYOUT_COMPRESSION;

	return erofs_inode_is_data_compressed(EROFS_V(inode)->datamode);

}



static inline bool is_inode_layout_inline(struct inode *inode)

static inline bool is_inode_flat_inline(struct inode *inode)

{

	return EROFS_V(inode)->datamode == EROFS_INODE_LAYOUT_INLINE;

	return EROFS_V(inode)->datamode == EROFS_INODE_FLAT_INLINE;

}



extern const struct super_operations erofs_sops;

drivers/staging/erofs/unzip_vle.c

+4 −4
Original line number Diff line number Diff line
@@ -1642,8 +1642,8 @@ vle_extent_blkaddr(struct inode *inode, pgoff_t index) 
	struct erofs_sb_info *sbi = EROFS_I_SB(inode);

	struct erofs_vnode *vi = EROFS_V(inode);



	unsigned int ofs = Z_EROFS_VLE_EXTENT_ALIGN(vi->inode_isize +

		vi->xattr_isize) + sizeof(struct erofs_extent_header) +

	unsigned int ofs = Z_EROFS_VLE_LEGACY_INDEX_ALIGN(vi->inode_isize +

							  vi->xattr_isize) +

		index * sizeof(struct z_erofs_vle_decompressed_index);



	return erofs_blknr(iloc(sbi, vi->nid) + ofs);
@@ -1655,8 +1655,8 @@ vle_extent_blkoff(struct inode *inode, pgoff_t index) 
	struct erofs_sb_info *sbi = EROFS_I_SB(inode);

	struct erofs_vnode *vi = EROFS_V(inode);



	unsigned int ofs = Z_EROFS_VLE_EXTENT_ALIGN(vi->inode_isize +

		vi->xattr_isize) + sizeof(struct erofs_extent_header) +

	unsigned int ofs = Z_EROFS_VLE_LEGACY_INDEX_ALIGN(vi->inode_isize +

							  vi->xattr_isize) +

		index * sizeof(struct z_erofs_vle_decompressed_index);



	return erofs_blkoff(iloc(sbi, vi->nid) + ofs);

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