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: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/erofs/data.c b/drivers/staging/erofs/data.c
index 746685f..cc31c3e 100644 (file)
--- a/drivers/staging/erofs/data.c
+++ b/drivers/staging/erofs/data.c
@@ -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);
 

diff --git a/drivers/staging/erofs/erofs_fs.h b/drivers/staging/erofs/erofs_fs.h
index 8ddb2b3..9a9aaf2 100644 (file)
--- a/drivers/staging/erofs/erofs_fs.h
+++ b/drivers/staging/erofs/erofs_fs.h
@@ -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);
 

diff --git a/drivers/staging/erofs/inode.c b/drivers/staging/erofs/inode.c
index e51348f..3539290 100644 (file)
--- a/drivers/staging/erofs/inode.c
+++ b/drivers/staging/erofs/inode.c
@@ -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) */

diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
index 1666cce..c851d0b 100644 (file)
--- a/drivers/staging/erofs/internal.h
+++ b/drivers/staging/erofs/internal.h
@@ -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;

diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c
index f3d0d2c..ae62293 100644 (file)
--- a/drivers/staging/erofs/unzip_vle.c
+++ b/drivers/staging/erofs/unzip_vle.c
@@ -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);