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staging: erofs: add compacted ondisk compression indexes

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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: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gao Xiang 2019-06-24 15:22:51 +08:00 committed by Greg Kroah-Hartman
parent e36472145a
commit ec8c244205
5 changed files with 62 additions and 31 deletions
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4
drivers/staging/erofs/data.c
View File

@ -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);

65
drivers/staging/erofs/erofs_fs.h
View File

@ -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);

5
drivers/staging/erofs/inode.c
View File

@ -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) */

11
drivers/staging/erofs/internal.h
View File

@ -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;

8
drivers/staging/erofs/unzip_vle.c
View File

@ -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);