// 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 SUMMARY_SIZE            (7)     /* sizeof(struct f2fs_summary) */
#define SUM_FOOTER_SIZE         (5)     /* sizeof(struct summary_footer) */

/* 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;

/*
 * 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;

/*
 * The nat_journal structure is a placeholder whose actual size varies depending
 * on the use of packed_ssa. Therefore, it must always be accessed only through
 * specific sets of macros and fields, and size calculations should use
 * size-related macros instead of sizeof().
 * Relevant macros: sbi->nat_journal_entries, nat_in_journal(),
 * nid_in_journal(), MAX_NAT_JENTRIES().
 */
struct nat_journal {
        struct nat_journal_entry entries[0];
} __packed;

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

/*
 * The sit_journal structure is a placeholder whose actual size varies depending
 * on the use of packed_ssa. Therefore, it must always be accessed only through
 * specific sets of macros and fields, and size calculations should use
 * size-related macros instead of sizeof().
 * Relevant macros: sbi->sit_journal_entries, sit_in_journal(),
 * segno_in_journal(), MAX_SIT_JENTRIES().
 */
struct sit_journal {
        struct sit_journal_entry entries[0];
} __packed;

struct f2fs_extra_info {
        __le64 kbytes_written;
        __u8 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
 *
 * The f2fs_summary_block structure is a placeholder whose actual size varies
 * depending on the use of packed_ssa. Therefore, it must always be accessed
 * only through specific sets of macros and fields, and size calculations should
 * use size-related macros instead of sizeof().
 * Relevant macros: sbi->sum_blocksize, sbi->entries_in_sum,
 * sbi->sum_entry_size, sum_entries(), sum_journal(), sum_footer().
 *
 * Summary Block Layout
 *
 * +-----------------------+ <--- Block Start
 * | struct f2fs_summary   |
 * | entries[0]            |
 * | ...                   |
 * | entries[N-1]          |
 * +-----------------------+
 * | struct f2fs_journal   |
 * +-----------------------+
 * | struct summary_footer |
 * +-----------------------+ <--- Block End
 */
struct f2fs_summary_block {
        struct f2fs_summary entries[0];
        // 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 */