Quelle f2fs_fs.h Sprache: C

// SPDX-License-Identifier: GPL-2.0
/**
* include/linux/f2fs_fs.h
*
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
*             http://www.samsung.com/
*/
#ifndef _LINUX_F2FS_FS_H
#define _LINUX_F2FS_FS_H

#include <linux/pagemap.h>
#include <linux/types.h>

#define F2FS_SUPER_OFFSET  1024 /* byte-size offset */
#define F2FS_MIN_LOG_SECTOR_SIZE 9 /* 9 bits for 512 bytes */
#define F2FS_MAX_LOG_SECTOR_SIZE PAGE_SHIFT /* Max is Block Size */
#define F2FS_LOG_SECTORS_PER_BLOCK (PAGE_SHIFT - 9) /* log number for sector/blk */
#define F2FS_BLKSIZE   PAGE_SIZE /* support only block == page */
#define F2FS_BLKSIZE_BITS  PAGE_SHIFT /* bits for F2FS_BLKSIZE */
#define F2FS_MAX_EXTENSION  64 /* # of extension entries */
#define F2FS_EXTENSION_LEN  8 /* max size of extension */

#define NULL_ADDR  ((block_t)0) /* used as block_t addresses */
#define NEW_ADDR  ((block_t)-1) /* used as block_t addresses */
#define COMPRESS_ADDR  ((block_t)-2) /* used as compressed data flag */

#define F2FS_BLKSIZE_MASK  (F2FS_BLKSIZE - 1)
#define F2FS_BYTES_TO_BLK(bytes) ((unsigned long long)(bytes) >> F2FS_BLKSIZE_BITS)
#define F2FS_BLK_TO_BYTES(blk)  ((unsigned long long)(blk) << F2FS_BLKSIZE_BITS)
#define F2FS_BLK_END_BYTES(blk)  (F2FS_BLK_TO_BYTES(blk + 1) - 1)
#define F2FS_BLK_ALIGN(x)  (F2FS_BYTES_TO_BLK((x) + F2FS_BLKSIZE - 1))

/* 0, 1(node nid), 2(meta nid) are reserved node id */
#define F2FS_RESERVED_NODE_NUM  3

#define F2FS_ROOT_INO(sbi) ((sbi)->root_ino_num)
#define F2FS_NODE_INO(sbi) ((sbi)->node_ino_num)
#define F2FS_META_INO(sbi) ((sbi)->meta_ino_num)
#define F2FS_COMPRESS_INO(sbi) (NM_I(sbi)->max_nid)

#define F2FS_MAX_QUOTAS  3

#define F2FS_ENC_UTF8_12_1 1

/* This flag is used by node and meta inodes, and by recovery */
#define GFP_F2FS_ZERO  (GFP_NOFS | __GFP_ZERO)

/*
* For further optimization on multi-head logs, on-disk layout supports maximum
* 16 logs by default. The number, 16, is expected to cover all the cases
* enoughly. The implementaion currently uses no more than 6 logs.
* Half the logs are used for nodes, and the other half are used for data.
*/
#define MAX_ACTIVE_LOGS 16
#define MAX_ACTIVE_NODE_LOGS 8
#define MAX_ACTIVE_DATA_LOGS 8

#define VERSION_LEN 256
#define MAX_VOLUME_NAME  512
#define MAX_PATH_LEN  64
#define MAX_DEVICES  8

/*
* For superblock
*/
struct f2fs_device {
__u8 path[MAX_PATH_LEN];
__le32 total_segments;
} __packed;

/* reason of stop_checkpoint */
enum stop_cp_reason {
STOP_CP_REASON_SHUTDOWN,
STOP_CP_REASON_FAULT_INJECT,
STOP_CP_REASON_META_PAGE,
STOP_CP_REASON_WRITE_FAIL,
STOP_CP_REASON_CORRUPTED_SUMMARY,
STOP_CP_REASON_UPDATE_INODE,
STOP_CP_REASON_FLUSH_FAIL,
STOP_CP_REASON_NO_SEGMENT,
STOP_CP_REASON_CORRUPTED_FREE_BITMAP,
STOP_CP_REASON_CORRUPTED_NID,
STOP_CP_REASON_MAX,
};

#define MAX_STOP_REASON   32

/* detail reason for EFSCORRUPTED */
enum f2fs_error {
ERROR_CORRUPTED_CLUSTER,
ERROR_FAIL_DECOMPRESSION,
ERROR_INVALID_BLKADDR,
ERROR_CORRUPTED_DIRENT,
ERROR_CORRUPTED_INODE,
ERROR_INCONSISTENT_SUMMARY,
ERROR_INCONSISTENT_FOOTER,
ERROR_INCONSISTENT_SUM_TYPE,
ERROR_CORRUPTED_JOURNAL,
ERROR_INCONSISTENT_NODE_COUNT,
ERROR_INCONSISTENT_BLOCK_COUNT,
ERROR_INVALID_CURSEG,
ERROR_INCONSISTENT_SIT,
ERROR_CORRUPTED_VERITY_XATTR,
ERROR_CORRUPTED_XATTR,
ERROR_INVALID_NODE_REFERENCE,
ERROR_INCONSISTENT_NAT,
ERROR_MAX,
};

#define MAX_F2FS_ERRORS   16

struct f2fs_super_block {
__le32 magic;   /* Magic Number */
__le16 major_ver;  /* Major Version */
__le16 minor_ver;  /* Minor Version */
__le32 log_sectorsize;  /* log2 sector size in bytes */
__le32 log_sectors_per_block; /* log2 # of sectors per block */
__le32 log_blocksize;  /* log2 block size in bytes */
__le32 log_blocks_per_seg; /* log2 # of blocks per segment */
__le32 segs_per_sec;  /* # of segments per section */
__le32 secs_per_zone;  /* # of sections per zone */
__le32 checksum_offset;  /* checksum offset inside super block */
__le64 block_count;  /* total # of user blocks */
__le32 section_count;  /* total # of sections */
__le32 segment_count;  /* total # of segments */
__le32 segment_count_ckpt; /* # of segments for checkpoint */
__le32 segment_count_sit; /* # of segments for SIT */
__le32 segment_count_nat; /* # of segments for NAT */
__le32 segment_count_ssa; /* # of segments for SSA */
__le32 segment_count_main; /* # of segments for main area */
__le32 segment0_blkaddr; /* start block address of segment 0 */
__le32 cp_blkaddr;  /* start block address of checkpoint */
__le32 sit_blkaddr;  /* start block address of SIT */
__le32 nat_blkaddr;  /* start block address of NAT */
__le32 ssa_blkaddr;  /* start block address of SSA */
__le32 main_blkaddr;  /* start block address of main area */
__le32 root_ino;  /* root inode number */
__le32 node_ino;  /* node inode number */
__le32 meta_ino;  /* meta inode number */
__u8 uuid[16];   /* 128-bit uuid for volume */
__le16 volume_name[MAX_VOLUME_NAME]; /* volume name */
__le32 extension_count;  /* # of extensions below */
__u8 extension_list[F2FS_MAX_EXTENSION][F2FS_EXTENSION_LEN];/* extension array */
__le32 cp_payload;
__u8 version[VERSION_LEN]; /* the kernel version */
__u8 init_version[VERSION_LEN]; /* the initial kernel version */
__le32 feature;   /* defined features */
__u8 encryption_level;  /* versioning level for encryption */
__u8 encrypt_pw_salt[16]; /* Salt used for string2key algorithm */
struct f2fs_device devs[MAX_DEVICES]; /* device list */
__le32 qf_ino[F2FS_MAX_QUOTAS]; /* quota inode numbers */
__u8 hot_ext_count;  /* # of hot file extension */
__le16  s_encoding;  /* Filename charset encoding */
__le16  s_encoding_flags; /* Filename charset encoding flags */
__u8 s_stop_reason[MAX_STOP_REASON]; /* stop checkpoint reason */
__u8 s_errors[MAX_F2FS_ERRORS];  /* reason of image corrupts */
__u8 reserved[258];  /* valid reserved region */
__le32 crc;   /* checksum of superblock */
} __packed;

/*
* For checkpoint
*/
#define CP_RESIZEFS_FLAG  0x00004000
#define CP_DISABLED_QUICK_FLAG  0x00002000
#define CP_DISABLED_FLAG  0x00001000
#define CP_QUOTA_NEED_FSCK_FLAG  0x00000800
#define CP_LARGE_NAT_BITMAP_FLAG 0x00000400
#define CP_NOCRC_RECOVERY_FLAG 0x00000200
#define CP_TRIMMED_FLAG  0x00000100
#define CP_NAT_BITS_FLAG 0x00000080
#define CP_CRC_RECOVERY_FLAG 0x00000040
#define CP_FASTBOOT_FLAG 0x00000020
#define CP_FSCK_FLAG  0x00000010
#define CP_ERROR_FLAG  0x00000008
#define CP_COMPACT_SUM_FLAG 0x00000004
#define CP_ORPHAN_PRESENT_FLAG 0x00000002
#define CP_UMOUNT_FLAG  0x00000001

#define F2FS_CP_PACKS  2 /* # of checkpoint packs */

struct f2fs_checkpoint {
__le64 checkpoint_ver;  /* checkpoint block version number */
__le64 user_block_count; /* # of user blocks */
__le64 valid_block_count; /* # of valid blocks in main area */
__le32 rsvd_segment_count; /* # of reserved segments for gc */
__le32 overprov_segment_count; /* # of overprovision segments */
__le32 free_segment_count; /* # of free segments in main area */

/* information of current node segments */
__le32 cur_node_segno[MAX_ACTIVE_NODE_LOGS];
__le16 cur_node_blkoff[MAX_ACTIVE_NODE_LOGS];
/* information of current data segments */
__le32 cur_data_segno[MAX_ACTIVE_DATA_LOGS];
__le16 cur_data_blkoff[MAX_ACTIVE_DATA_LOGS];
__le32 ckpt_flags;  /* Flags : umount and journal_present */
__le32 cp_pack_total_block_count; /* total # of one cp pack */
__le32 cp_pack_start_sum; /* start block number of data summary */
__le32 valid_node_count; /* Total number of valid nodes */
__le32 valid_inode_count; /* Total number of valid inodes */
__le32 next_free_nid;  /* Next free node number */
__le32 sit_ver_bitmap_bytesize; /* Default value 64 */
__le32 nat_ver_bitmap_bytesize; /* Default value 256 */
__le32 checksum_offset;  /* checksum offset inside cp block */
__le64 elapsed_time;  /* mounted time */
/* allocation type of current segment */
unsigned char alloc_type[MAX_ACTIVE_LOGS];

/* SIT and NAT version bitmap */
unsigned char sit_nat_version_bitmap[];
} __packed;

#define CP_CHKSUM_OFFSET (F2FS_BLKSIZE - sizeof(__le32)) /* default chksum offset in checkpoint */
#define CP_MIN_CHKSUM_OFFSET      \
(offsetof(struct f2fs_checkpoint, sit_nat_version_bitmap))

/*
* For orphan inode management
*/
#define F2FS_ORPHANS_PER_BLOCK ((F2FS_BLKSIZE - 4 * sizeof(__le32)) / sizeof(__le32))

#define GET_ORPHAN_BLOCKS(n) (((n) + F2FS_ORPHANS_PER_BLOCK - 1) / \
     F2FS_ORPHANS_PER_BLOCK)

struct f2fs_orphan_block {
__le32 ino[F2FS_ORPHANS_PER_BLOCK]; /* inode numbers */
__le32 reserved; /* reserved */
__le16 blk_addr; /* block index in current CP */
__le16 blk_count; /* Number of orphan inode blocks in CP */
__le32 entry_count; /* Total number of orphan nodes in current CP */
__le32 check_sum; /* CRC32 for orphan inode block */
} __packed;

/*
* For NODE structure
*/
struct f2fs_extent {
__le32 fofs;  /* start file offset of the extent */
__le32 blk;  /* start block address of the extent */
__le32 len;  /* length of the extent */
} __packed;

#define F2FS_NAME_LEN  255
/* 200 bytes for inline xattrs by default */
#define DEFAULT_INLINE_XATTR_ADDRS 50

#define OFFSET_OF_END_OF_I_EXT  360
#define SIZE_OF_I_NID   20

struct node_footer {
__le32 nid;  /* node id */
__le32 ino;  /* inode number */
__le32 flag;  /* include cold/fsync/dentry marks and offset */
__le64 cp_ver;  /* checkpoint version */
__le32 next_blkaddr; /* next node page block address */
} __packed;

/* Address Pointers in an Inode */
#define DEF_ADDRS_PER_INODE ((F2FS_BLKSIZE - OFFSET_OF_END_OF_I_EXT \
     - SIZE_OF_I_NID \
     - sizeof(struct node_footer)) / sizeof(__le32))
#define CUR_ADDRS_PER_INODE(inode) (DEF_ADDRS_PER_INODE - \
     get_extra_isize(inode))
#define DEF_NIDS_PER_INODE 5 /* Node IDs in an Inode */
#define ADDRS_PER_INODE(inode) addrs_per_page(inode, true)
/* Address Pointers in a Direct Block */
#define DEF_ADDRS_PER_BLOCK ((F2FS_BLKSIZE - sizeof(struct node_footer)) / sizeof(__le32))
#define ADDRS_PER_BLOCK(inode) addrs_per_page(inode, false)
/* Node IDs in an Indirect Block */
#define NIDS_PER_BLOCK  ((F2FS_BLKSIZE - sizeof(struct node_footer)) / sizeof(__le32))

#define ADDRS_PER_PAGE(folio, inode) (addrs_per_page(inode, IS_INODE(folio)))

#define NODE_DIR1_BLOCK  (DEF_ADDRS_PER_INODE + 1)
#define NODE_DIR2_BLOCK  (DEF_ADDRS_PER_INODE + 2)
#define NODE_IND1_BLOCK  (DEF_ADDRS_PER_INODE + 3)
#define NODE_IND2_BLOCK  (DEF_ADDRS_PER_INODE + 4)
#define NODE_DIND_BLOCK  (DEF_ADDRS_PER_INODE + 5)

#define F2FS_INLINE_XATTR 0x01 /* file inline xattr flag */
#define F2FS_INLINE_DATA 0x02 /* file inline data flag */
#define F2FS_INLINE_DENTRY 0x04 /* file inline dentry flag */
#define F2FS_DATA_EXIST  0x08 /* file inline data exist flag */
#define F2FS_INLINE_DOTS 0x10 /* file having implicit dot dentries (obsolete) */
#define F2FS_EXTRA_ATTR  0x20 /* file having extra attribute */
#define F2FS_PIN_FILE  0x40 /* file should not be gced */
#define F2FS_COMPRESS_RELEASED 0x80 /* file released compressed blocks */

struct f2fs_inode {
__le16 i_mode;   /* file mode */
__u8 i_advise;   /* file hints */
__u8 i_inline;   /* file inline flags */
__le32 i_uid;   /* user ID */
__le32 i_gid;   /* group ID */
__le32 i_links;   /* links count */
__le64 i_size;   /* file size in bytes */
__le64 i_blocks;  /* file size in blocks */
__le64 i_atime;   /* access time */
__le64 i_ctime;   /* change time */
__le64 i_mtime;   /* modification time */
__le32 i_atime_nsec;  /* access time in nano scale */
__le32 i_ctime_nsec;  /* change time in nano scale */
__le32 i_mtime_nsec;  /* modification time in nano scale */
__le32 i_generation;  /* file version (for NFS) */
union {
  __le32 i_current_depth; /* only for directory depth */
  __le16 i_gc_failures; /*
* # of gc failures on pinned file.
* only for regular files.
*/
};
__le32 i_xattr_nid;  /* nid to save xattr */
__le32 i_flags;   /* file attributes */
__le32 i_pino;   /* parent inode number */
__le32 i_namelen;  /* file name length */
__u8 i_name[F2FS_NAME_LEN]; /* file name for SPOR */
__u8 i_dir_level;  /* dentry_level for large dir */

struct f2fs_extent i_ext; /* caching a largest extent */

union {
  struct {
   __le16 i_extra_isize; /* extra inode attribute size */
   __le16 i_inline_xattr_size; /* inline xattr size, unit: 4 bytes */
   __le32 i_projid; /* project id */
   __le32 i_inode_checksum;/* inode meta checksum */
   __le64 i_crtime; /* creation time */
   __le32 i_crtime_nsec; /* creation time in nano scale */
   __le64 i_compr_blocks; /* # of compressed blocks */
   __u8 i_compress_algorithm; /* compress algorithm */
   __u8 i_log_cluster_size; /* log of cluster size */
   __le16 i_compress_flag;  /* compress flag */
      /* 0 bit: chksum flag
* [8,15] bits: compress level
*/
   __le32 i_extra_end[0]; /* for attribute size calculation */
  } __packed;
  __le32 i_addr[DEF_ADDRS_PER_INODE]; /* Pointers to data blocks */
};
__le32 i_nid[DEF_NIDS_PER_INODE]; /* direct(2), indirect(2),
double_indirect(1) node id */
} __packed;

struct direct_node {
__le32 addr[DEF_ADDRS_PER_BLOCK]; /* array of data block address */
} __packed;

struct indirect_node {
__le32 nid[NIDS_PER_BLOCK]; /* array of data block address */
} __packed;

enum {
COLD_BIT_SHIFT = 0,
FSYNC_BIT_SHIFT,
DENT_BIT_SHIFT,
OFFSET_BIT_SHIFT
};

#define OFFSET_BIT_MASK  GENMASK(OFFSET_BIT_SHIFT - 1, 0)

struct f2fs_node {
/* can be one of three types: inode, direct, and indirect types */
union {
  struct f2fs_inode i;
  struct direct_node dn;
  struct indirect_node in;
};
struct node_footer footer;
} __packed;

/*
* For NAT entries
*/
#define NAT_ENTRY_PER_BLOCK (F2FS_BLKSIZE / sizeof(struct f2fs_nat_entry))

struct f2fs_nat_entry {
__u8 version;  /* latest version of cached nat entry */
__le32 ino;  /* inode number */
__le32 block_addr; /* block address */
} __packed;

struct f2fs_nat_block {
struct f2fs_nat_entry entries[NAT_ENTRY_PER_BLOCK];
} __packed;

/*
* For SIT entries
*
* A validity bitmap of 64 bytes covers 512 blocks of area. For a 4K page size,
* this results in a segment size of 2MB. For 16k pages, the default segment size
* is 8MB.
* Not allow to change this.
*/
#define SIT_VBLOCK_MAP_SIZE 64
#define SIT_ENTRY_PER_BLOCK (F2FS_BLKSIZE / sizeof(struct f2fs_sit_entry))

/*
* F2FS uses 4 bytes to represent block address. As a result, supported size of
* disk is 16 TB for a 4K page size and 64 TB for a 16K page size and it equals
* to 16 * 1024 * 1024 / 2 segments.
*/
#define F2FS_MAX_SEGMENT       ((16 * 1024 * 1024) / 2)

/*
* Note that f2fs_sit_entry->vblocks has the following bit-field information.
* [15:10] : allocation type such as CURSEG_XXXX_TYPE
* [9:0] : valid block count
*/
#define SIT_VBLOCKS_SHIFT 10
#define SIT_VBLOCKS_MASK ((1 << SIT_VBLOCKS_SHIFT) - 1)
#define GET_SIT_VBLOCKS(raw_sit)    \
(le16_to_cpu((raw_sit)->vblocks) & SIT_VBLOCKS_MASK)
#define GET_SIT_TYPE(raw_sit)     \
((le16_to_cpu((raw_sit)->vblocks) & ~SIT_VBLOCKS_MASK) \
  >> SIT_VBLOCKS_SHIFT)

struct f2fs_sit_entry {
__le16 vblocks;    /* reference above */
__u8 valid_map[SIT_VBLOCK_MAP_SIZE]; /* bitmap for valid blocks */
__le64 mtime;    /* segment age for cleaning */
} __packed;

struct f2fs_sit_block {
struct f2fs_sit_entry entries[SIT_ENTRY_PER_BLOCK];
} __packed;

/*
* For segment summary
*
* One summary block with 4KB size contains exactly 512 summary entries, which
* represents exactly one segment with 2MB size.
* Similarly, in the case of block with 16KB size, it represents one segment with 8MB size.
* Not allow to change the basic units.
*
* NOTE: For initializing fields, you must use set_summary
*
* - If data page, nid represents dnode's nid
* - If node page, nid represents the node page's nid.
*
* The ofs_in_node is used by only data page. It represents offset
* from node's page's beginning to get a data block address.
* ex) data_blkaddr = (block_t)(nodepage_start_address + ofs_in_node)
*/
#define ENTRIES_IN_SUM  (F2FS_BLKSIZE / 8)
#define SUMMARY_SIZE  (7) /* sizeof(struct f2fs_summary) */
#define SUM_FOOTER_SIZE  (5) /* sizeof(struct summary_footer) */
#define SUM_ENTRY_SIZE  (SUMMARY_SIZE * ENTRIES_IN_SUM)

/* a summary entry for a block in a segment */
struct f2fs_summary {
__le32 nid;  /* parent node id */
union {
  __u8 reserved[3];
  struct {
   __u8 version;  /* node version number */
   __le16 ofs_in_node; /* block index in parent node */
  } __packed;
};
} __packed;

/* summary block type, node or data, is stored to the summary_footer */
#define SUM_TYPE_NODE  (1)
#define SUM_TYPE_DATA  (0)

struct summary_footer {
unsigned char entry_type; /* SUM_TYPE_XXX */
__le32 check_sum;  /* summary checksum */
} __packed;

#define SUM_JOURNAL_SIZE (F2FS_BLKSIZE - SUM_FOOTER_SIZE -\
    SUM_ENTRY_SIZE)
#define NAT_JOURNAL_ENTRIES ((SUM_JOURNAL_SIZE - 2) /\
    sizeof(struct nat_journal_entry))
#define NAT_JOURNAL_RESERVED ((SUM_JOURNAL_SIZE - 2) %\
    sizeof(struct nat_journal_entry))
#define SIT_JOURNAL_ENTRIES ((SUM_JOURNAL_SIZE - 2) /\
    sizeof(struct sit_journal_entry))
#define SIT_JOURNAL_RESERVED ((SUM_JOURNAL_SIZE - 2) %\
    sizeof(struct sit_journal_entry))

/* Reserved area should make size of f2fs_extra_info equals to
* that of nat_journal and sit_journal.
*/
#define EXTRA_INFO_RESERVED (SUM_JOURNAL_SIZE - 2 - 8)

/*
* frequently updated NAT/SIT entries can be stored in the spare area in
* summary blocks
*/
enum {
NAT_JOURNAL = 0,
SIT_JOURNAL
};

struct nat_journal_entry {
__le32 nid;
struct f2fs_nat_entry ne;
} __packed;

struct nat_journal {
struct nat_journal_entry entries[NAT_JOURNAL_ENTRIES];
__u8 reserved[NAT_JOURNAL_RESERVED];
} __packed;

struct sit_journal_entry {
__le32 segno;
struct f2fs_sit_entry se;
} __packed;

struct sit_journal {
struct sit_journal_entry entries[SIT_JOURNAL_ENTRIES];
__u8 reserved[SIT_JOURNAL_RESERVED];
} __packed;

struct f2fs_extra_info {
__le64 kbytes_written;
__u8 reserved[EXTRA_INFO_RESERVED];
} __packed;

struct f2fs_journal {
union {
  __le16 n_nats;
  __le16 n_sits;
};
/* spare area is used by NAT or SIT journals or extra info */
union {
  struct nat_journal nat_j;
  struct sit_journal sit_j;
  struct f2fs_extra_info info;
};
} __packed;

/* Block-sized summary block structure */
struct f2fs_summary_block {
struct f2fs_summary entries[ENTRIES_IN_SUM];
struct f2fs_journal journal;
struct summary_footer footer;
} __packed;

/*
* For directory operations
*/
#define F2FS_DOT_HASH  0
#define F2FS_DDOT_HASH  F2FS_DOT_HASH
#define F2FS_MAX_HASH  (~((0x3ULL) << 62))
#define F2FS_HASH_COL_BIT ((0x1ULL) << 63)

typedef __le32 f2fs_hash_t;

/* One directory entry slot covers 8bytes-long file name */
#define F2FS_SLOT_LEN  8
#define F2FS_SLOT_LEN_BITS 3

#define GET_DENTRY_SLOTS(x) (((x) + F2FS_SLOT_LEN - 1) >> F2FS_SLOT_LEN_BITS)

/* MAX level for dir lookup */
#define MAX_DIR_HASH_DEPTH 63

/* MAX buckets in one level of dir */
#define MAX_DIR_BUCKETS  BIT((MAX_DIR_HASH_DEPTH / 2) - 1)

/*
* space utilization of regular dentry and inline dentry (w/o extra reservation)
* when block size is 4KB.
* regular dentry inline dentry (def) inline dentry (min)
* bitmap 1 * 27 = 27 1 * 23 = 23 1 * 1 = 1
* reserved 1 * 3 = 3 1 * 7 = 7 1 * 1 = 1
* dentry 11 * 214 = 2354 11 * 182 = 2002 11 * 2 = 22
* filename 8 * 214 = 1712 8 * 182 = 1456 8 * 2 = 16
* total 4096 3488 40
*
* Note: there are more reserved space in inline dentry than in regular
* dentry, when converting inline dentry we should handle this carefully.
*/

/* the number of dentry in a block */
#define NR_DENTRY_IN_BLOCK ((BITS_PER_BYTE * F2FS_BLKSIZE) / \
     ((SIZE_OF_DIR_ENTRY + F2FS_SLOT_LEN) * BITS_PER_BYTE + 1))
#define SIZE_OF_DIR_ENTRY 11 /* by byte */
#define SIZE_OF_DENTRY_BITMAP ((NR_DENTRY_IN_BLOCK + BITS_PER_BYTE - 1) / \
     BITS_PER_BYTE)
#define SIZE_OF_RESERVED (F2FS_BLKSIZE - ((SIZE_OF_DIR_ENTRY + \
    F2FS_SLOT_LEN) * \
    NR_DENTRY_IN_BLOCK + SIZE_OF_DENTRY_BITMAP))
#define MIN_INLINE_DENTRY_SIZE  40 /* just include '.' and '..' entries */

/* One directory entry slot representing F2FS_SLOT_LEN-sized file name */
struct f2fs_dir_entry {
__le32 hash_code; /* hash code of file name */
__le32 ino;  /* inode number */
__le16 name_len; /* length of file name */
__u8 file_type;  /* file type */
} __packed;

/* Block-sized directory entry block */
struct f2fs_dentry_block {
/* validity bitmap for directory entries in each block */
__u8 dentry_bitmap[SIZE_OF_DENTRY_BITMAP];
__u8 reserved[SIZE_OF_RESERVED];
struct f2fs_dir_entry dentry[NR_DENTRY_IN_BLOCK];
__u8 filename[NR_DENTRY_IN_BLOCK][F2FS_SLOT_LEN];
} __packed;

#define F2FS_DEF_PROJID  0 /* default project ID */

#endif  /* _LINUX_F2FS_FS_H */

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Die farbliche Syntaxdarstellung ist noch experimentell.