LXR linux/include/linux/f2fs

   1/**
   2 * include/linux/f2fs_fs.h
   3 *
   4 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   5 *             http://www.samsung.com/
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 */
  11#ifndef _LINUX_F2FS_FS_H
  12#define _LINUX_F2FS_FS_H
  13
  14#include <linux/pagemap.h>
  15#include <linux/types.h>
  16
  17#define F2FS_SUPER_OFFSET               1024    /* byte-size offset */
  18#define F2FS_MIN_LOG_SECTOR_SIZE        9       /* 9 bits for 512 bytes */
  19#define F2FS_MAX_LOG_SECTOR_SIZE        12      /* 12 bits for 4096 bytes */
  20#define F2FS_LOG_SECTORS_PER_BLOCK      3       /* log number for sector/blk */
  21#define F2FS_BLKSIZE                    4096    /* support only 4KB block */
  22#define F2FS_BLKSIZE_BITS               12      /* bits for F2FS_BLKSIZE */
  23#define F2FS_MAX_EXTENSION              64      /* # of extension entries */
  24#define F2FS_EXTENSION_LEN              8       /* max size of extension */
  25#define F2FS_BLK_ALIGN(x)       (((x) + F2FS_BLKSIZE - 1) >> F2FS_BLKSIZE_BITS)
  26
  27#define NULL_ADDR               ((block_t)0)    /* used as block_t addresses */
  28#define NEW_ADDR                ((block_t)-1)   /* used as block_t addresses */
  29
  30#define F2FS_BYTES_TO_BLK(bytes)        ((bytes) >> F2FS_BLKSIZE_BITS)
  31#define F2FS_BLK_TO_BYTES(blk)          ((blk) << F2FS_BLKSIZE_BITS)
  32
  33/* 0, 1(node nid), 2(meta nid) are reserved node id */
  34#define F2FS_RESERVED_NODE_NUM          3
  35
  36#define F2FS_ROOT_INO(sbi)      ((sbi)->root_ino_num)
  37#define F2FS_NODE_INO(sbi)      ((sbi)->node_ino_num)
  38#define F2FS_META_INO(sbi)      ((sbi)->meta_ino_num)
  39
  40#define F2FS_MAX_QUOTAS         3
  41
  42#define F2FS_IO_SIZE(sbi)       (1 << F2FS_OPTION(sbi).write_io_size_bits) /* Blocks */
  43#define F2FS_IO_SIZE_KB(sbi)    (1 << (F2FS_OPTION(sbi).write_io_size_bits + 2)) /* KB */
  44#define F2FS_IO_SIZE_BYTES(sbi) (1 << (F2FS_OPTION(sbi).write_io_size_bits + 12)) /* B */
  45#define F2FS_IO_SIZE_BITS(sbi)  (F2FS_OPTION(sbi).write_io_size_bits) /* power of 2 */
  46#define F2FS_IO_SIZE_MASK(sbi)  (F2FS_IO_SIZE(sbi) - 1)
  47
  48/* This flag is used by node and meta inodes, and by recovery */
  49#define GFP_F2FS_ZERO           (GFP_NOFS | __GFP_ZERO)
  50
  51/*
  52 * For further optimization on multi-head logs, on-disk layout supports maximum
  53 * 16 logs by default. The number, 16, is expected to cover all the cases
  54 * enoughly. The implementaion currently uses no more than 6 logs.
  55 * Half the logs are used for nodes, and the other half are used for data.
  56 */
  57#define MAX_ACTIVE_LOGS 16
  58#define MAX_ACTIVE_NODE_LOGS    8
  59#define MAX_ACTIVE_DATA_LOGS    8
  60
  61#define VERSION_LEN     256
  62#define MAX_VOLUME_NAME         512
  63#define MAX_PATH_LEN            64
  64#define MAX_DEVICES             8
  65
  66/*
  67 * For superblock
  68 */
  69struct f2fs_device {
  70        __u8 path[MAX_PATH_LEN];
  71        __le32 total_segments;
  72} __packed;
  73
  74struct f2fs_super_block {
  75        __le32 magic;                   /* Magic Number */
  76        __le16 major_ver;               /* Major Version */
  77        __le16 minor_ver;               /* Minor Version */
  78        __le32 log_sectorsize;          /* log2 sector size in bytes */
  79        __le32 log_sectors_per_block;   /* log2 # of sectors per block */
  80        __le32 log_blocksize;           /* log2 block size in bytes */
  81        __le32 log_blocks_per_seg;      /* log2 # of blocks per segment */
  82        __le32 segs_per_sec;            /* # of segments per section */
  83        __le32 secs_per_zone;           /* # of sections per zone */
  84        __le32 checksum_offset;         /* checksum offset inside super block */
  85        __le64 block_count;             /* total # of user blocks */
  86        __le32 section_count;           /* total # of sections */
  87        __le32 segment_count;           /* total # of segments */
  88        __le32 segment_count_ckpt;      /* # of segments for checkpoint */
  89        __le32 segment_count_sit;       /* # of segments for SIT */
  90        __le32 segment_count_nat;       /* # of segments for NAT */
  91        __le32 segment_count_ssa;       /* # of segments for SSA */
  92        __le32 segment_count_main;      /* # of segments for main area */
  93        __le32 segment0_blkaddr;        /* start block address of segment 0 */
  94        __le32 cp_blkaddr;              /* start block address of checkpoint */
  95        __le32 sit_blkaddr;             /* start block address of SIT */
  96        __le32 nat_blkaddr;             /* start block address of NAT */
  97        __le32 ssa_blkaddr;             /* start block address of SSA */
  98        __le32 main_blkaddr;            /* start block address of main area */
  99        __le32 root_ino;                /* root inode number */
 100        __le32 node_ino;                /* node inode number */
 101        __le32 meta_ino;                /* meta inode number */
 102        __u8 uuid[16];                  /* 128-bit uuid for volume */
 103        __le16 volume_name[MAX_VOLUME_NAME];    /* volume name */
 104        __le32 extension_count;         /* # of extensions below */
 105        __u8 extension_list[F2FS_MAX_EXTENSION][F2FS_EXTENSION_LEN];/* extension array */
 106        __le32 cp_payload;
 107        __u8 version[VERSION_LEN];      /* the kernel version */
 108        __u8 init_version[VERSION_LEN]; /* the initial kernel version */
 109        __le32 feature;                 /* defined features */
 110        __u8 encryption_level;          /* versioning level for encryption */
 111        __u8 encrypt_pw_salt[16];       /* Salt used for string2key algorithm */
 112        struct f2fs_device devs[MAX_DEVICES];   /* device list */
 113        __le32 qf_ino[F2FS_MAX_QUOTAS]; /* quota inode numbers */
 114        __u8 hot_ext_count;             /* # of hot file extension */
 115        __u8 reserved[314];             /* valid reserved region */
 116} __packed;
 117
 118/*
 119 * For checkpoint
 120 */
 121#define CP_LARGE_NAT_BITMAP_FLAG        0x00000400
 122#define CP_NOCRC_RECOVERY_FLAG  0x00000200
 123#define CP_TRIMMED_FLAG         0x00000100
 124#define CP_NAT_BITS_FLAG        0x00000080
 125#define CP_CRC_RECOVERY_FLAG    0x00000040
 126#define CP_FASTBOOT_FLAG        0x00000020
 127#define CP_FSCK_FLAG            0x00000010
 128#define CP_ERROR_FLAG           0x00000008
 129#define CP_COMPACT_SUM_FLAG     0x00000004
 130#define CP_ORPHAN_PRESENT_FLAG  0x00000002
 131#define CP_UMOUNT_FLAG          0x00000001
 132
 133#define F2FS_CP_PACKS           2       /* # of checkpoint packs */
 134
 135struct f2fs_checkpoint {
 136        __le64 checkpoint_ver;          /* checkpoint block version number */
 137        __le64 user_block_count;        /* # of user blocks */
 138        __le64 valid_block_count;       /* # of valid blocks in main area */
 139        __le32 rsvd_segment_count;      /* # of reserved segments for gc */
 140        __le32 overprov_segment_count;  /* # of overprovision segments */
 141        __le32 free_segment_count;      /* # of free segments in main area */
 142
 143        /* information of current node segments */
 144        __le32 cur_node_segno[MAX_ACTIVE_NODE_LOGS];
 145        __le16 cur_node_blkoff[MAX_ACTIVE_NODE_LOGS];
 146        /* information of current data segments */
 147        __le32 cur_data_segno[MAX_ACTIVE_DATA_LOGS];
 148        __le16 cur_data_blkoff[MAX_ACTIVE_DATA_LOGS];
 149        __le32 ckpt_flags;              /* Flags : umount and journal_present */
 150        __le32 cp_pack_total_block_count;       /* total # of one cp pack */
 151        __le32 cp_pack_start_sum;       /* start block number of data summary */
 152        __le32 valid_node_count;        /* Total number of valid nodes */
 153        __le32 valid_inode_count;       /* Total number of valid inodes */
 154        __le32 next_free_nid;           /* Next free node number */
 155        __le32 sit_ver_bitmap_bytesize; /* Default value 64 */
 156        __le32 nat_ver_bitmap_bytesize; /* Default value 256 */
 157        __le32 checksum_offset;         /* checksum offset inside cp block */
 158        __le64 elapsed_time;            /* mounted time */
 159        /* allocation type of current segment */
 160        unsigned char alloc_type[MAX_ACTIVE_LOGS];
 161
 162        /* SIT and NAT version bitmap */
 163        unsigned char sit_nat_version_bitmap[1];
 164} __packed;
 165
 166/*
 167 * For orphan inode management
 168 */
 169#define F2FS_ORPHANS_PER_BLOCK  1020
 170
 171#define GET_ORPHAN_BLOCKS(n)    (((n) + F2FS_ORPHANS_PER_BLOCK - 1) / \
 172                                        F2FS_ORPHANS_PER_BLOCK)
 173
 174struct f2fs_orphan_block {
 175        __le32 ino[F2FS_ORPHANS_PER_BLOCK];     /* inode numbers */
 176        __le32 reserved;        /* reserved */
 177        __le16 blk_addr;        /* block index in current CP */
 178        __le16 blk_count;       /* Number of orphan inode blocks in CP */
 179        __le32 entry_count;     /* Total number of orphan nodes in current CP */
 180        __le32 check_sum;       /* CRC32 for orphan inode block */
 181} __packed;
 182
 183/*
 184 * For NODE structure
 185 */
 186struct f2fs_extent {
 187        __le32 fofs;            /* start file offset of the extent */
 188        __le32 blk;             /* start block address of the extent */
 189        __le32 len;             /* lengh of the extent */
 190} __packed;
 191
 192#define F2FS_NAME_LEN           255
 193/* 200 bytes for inline xattrs by default */
 194#define DEFAULT_INLINE_XATTR_ADDRS      50
 195#define DEF_ADDRS_PER_INODE     923     /* Address Pointers in an Inode */
 196#define CUR_ADDRS_PER_INODE(inode)      (DEF_ADDRS_PER_INODE - \
 197                                        get_extra_isize(inode))
 198#define DEF_NIDS_PER_INODE      5       /* Node IDs in an Inode */
 199#define ADDRS_PER_INODE(inode)  addrs_per_inode(inode)
 200#define ADDRS_PER_BLOCK         1018    /* Address Pointers in a Direct Block */
 201#define NIDS_PER_BLOCK          1018    /* Node IDs in an Indirect Block */
 202
 203#define ADDRS_PER_PAGE(page, inode)     \
 204        (IS_INODE(page) ? ADDRS_PER_INODE(inode) : ADDRS_PER_BLOCK)
 205
 206#define NODE_DIR1_BLOCK         (DEF_ADDRS_PER_INODE + 1)
 207#define NODE_DIR2_BLOCK         (DEF_ADDRS_PER_INODE + 2)
 208#define NODE_IND1_BLOCK         (DEF_ADDRS_PER_INODE + 3)
 209#define NODE_IND2_BLOCK         (DEF_ADDRS_PER_INODE + 4)
 210#define NODE_DIND_BLOCK         (DEF_ADDRS_PER_INODE + 5)
 211
 212#define F2FS_INLINE_XATTR       0x01    /* file inline xattr flag */
 213#define F2FS_INLINE_DATA        0x02    /* file inline data flag */
 214#define F2FS_INLINE_DENTRY      0x04    /* file inline dentry flag */
 215#define F2FS_DATA_EXIST         0x08    /* file inline data exist flag */
 216#define F2FS_INLINE_DOTS        0x10    /* file having implicit dot dentries */
 217#define F2FS_EXTRA_ATTR         0x20    /* file having extra attribute */
 218#define F2FS_PIN_FILE           0x40    /* file should not be gced */
 219
 220struct f2fs_inode {
 221        __le16 i_mode;                  /* file mode */
 222        __u8 i_advise;                  /* file hints */
 223        __u8 i_inline;                  /* file inline flags */
 224        __le32 i_uid;                   /* user ID */
 225        __le32 i_gid;                   /* group ID */
 226        __le32 i_links;                 /* links count */
 227        __le64 i_size;                  /* file size in bytes */
 228        __le64 i_blocks;                /* file size in blocks */
 229        __le64 i_atime;                 /* access time */
 230        __le64 i_ctime;                 /* change time */
 231        __le64 i_mtime;                 /* modification time */
 232        __le32 i_atime_nsec;            /* access time in nano scale */
 233        __le32 i_ctime_nsec;            /* change time in nano scale */
 234        __le32 i_mtime_nsec;            /* modification time in nano scale */
 235        __le32 i_generation;            /* file version (for NFS) */
 236        union {
 237                __le32 i_current_depth; /* only for directory depth */
 238                __le16 i_gc_failures;   /*
 239                                         * # of gc failures on pinned file.
 240                                         * only for regular files.
 241                                         */
 242        };
 243        __le32 i_xattr_nid;             /* nid to save xattr */
 244        __le32 i_flags;                 /* file attributes */
 245        __le32 i_pino;                  /* parent inode number */
 246        __le32 i_namelen;               /* file name length */
 247        __u8 i_name[F2FS_NAME_LEN];     /* file name for SPOR */
 248        __u8 i_dir_level;               /* dentry_level for large dir */
 249
 250        struct f2fs_extent i_ext;       /* caching a largest extent */
 251
 252        union {
 253                struct {
 254                        __le16 i_extra_isize;   /* extra inode attribute size */
 255                        __le16 i_inline_xattr_size;     /* inline xattr size, unit: 4 bytes */
 256                        __le32 i_projid;        /* project id */
 257                        __le32 i_inode_checksum;/* inode meta checksum */
 258                        __le64 i_crtime;        /* creation time */
 259                        __le32 i_crtime_nsec;   /* creation time in nano scale */
 260                        __le32 i_extra_end[0];  /* for attribute size calculation */
 261                } __packed;
 262                __le32 i_addr[DEF_ADDRS_PER_INODE];     /* Pointers to data blocks */
 263        };
 264        __le32 i_nid[DEF_NIDS_PER_INODE];       /* direct(2), indirect(2),
 265                                                double_indirect(1) node id */
 266} __packed;
 267
 268struct direct_node {
 269        __le32 addr[ADDRS_PER_BLOCK];   /* array of data block address */
 270} __packed;
 271
 272struct indirect_node {
 273        __le32 nid[NIDS_PER_BLOCK];     /* array of data block address */
 274} __packed;
 275
 276enum {
 277        COLD_BIT_SHIFT = 0,
 278        FSYNC_BIT_SHIFT,
 279        DENT_BIT_SHIFT,
 280        OFFSET_BIT_SHIFT
 281};
 282
 283#define OFFSET_BIT_MASK         (0x07)  /* (0x01 << OFFSET_BIT_SHIFT) - 1 */
 284
 285struct node_footer {
 286        __le32 nid;             /* node id */
 287        __le32 ino;             /* inode nunmber */
 288        __le32 flag;            /* include cold/fsync/dentry marks and offset */
 289        __le64 cp_ver;          /* checkpoint version */
 290        __le32 next_blkaddr;    /* next node page block address */
 291} __packed;
 292
 293struct f2fs_node {
 294        /* can be one of three types: inode, direct, and indirect types */
 295        union {
 296                struct f2fs_inode i;
 297                struct direct_node dn;
 298                struct indirect_node in;
 299        };
 300        struct node_footer footer;
 301} __packed;
 302
 303/*
 304 * For NAT entries
 305 */
 306#define NAT_ENTRY_PER_BLOCK (PAGE_SIZE / sizeof(struct f2fs_nat_entry))
 307#define NAT_ENTRY_BITMAP_SIZE   ((NAT_ENTRY_PER_BLOCK + 7) / 8)
 308#define NAT_ENTRY_BITMAP_SIZE_ALIGNED                           \
 309        ((NAT_ENTRY_BITMAP_SIZE + BITS_PER_LONG - 1) /          \
 310        BITS_PER_LONG * BITS_PER_LONG)
 311
 312
 313struct f2fs_nat_entry {
 314        __u8 version;           /* latest version of cached nat entry */
 315        __le32 ino;             /* inode number */
 316        __le32 block_addr;      /* block address */
 317} __packed;
 318
 319struct f2fs_nat_block {
 320        struct f2fs_nat_entry entries[NAT_ENTRY_PER_BLOCK];
 321} __packed;
 322
 323/*
 324 * For SIT entries
 325 *
 326 * Each segment is 2MB in size by default so that a bitmap for validity of
 327 * there-in blocks should occupy 64 bytes, 512 bits.
 328 * Not allow to change this.
 329 */
 330#define SIT_VBLOCK_MAP_SIZE 64
 331#define SIT_ENTRY_PER_BLOCK (PAGE_SIZE / sizeof(struct f2fs_sit_entry))
 332
 333/*
 334 * F2FS uses 4 bytes to represent block address. As a result, supported size of
 335 * disk is 16 TB and it equals to 16 * 1024 * 1024 / 2 segments.
 336 */
 337#define F2FS_MAX_SEGMENT       ((16 * 1024 * 1024) / 2)
 338
 339/*
 340 * Note that f2fs_sit_entry->vblocks has the following bit-field information.
 341 * [15:10] : allocation type such as CURSEG_XXXX_TYPE
 342 * [9:0] : valid block count
 343 */
 344#define SIT_VBLOCKS_SHIFT       10
 345#define SIT_VBLOCKS_MASK        ((1 << SIT_VBLOCKS_SHIFT) - 1)
 346#define GET_SIT_VBLOCKS(raw_sit)                                \
 347        (le16_to_cpu((raw_sit)->vblocks) & SIT_VBLOCKS_MASK)
 348#define GET_SIT_TYPE(raw_sit)                                   \
 349        ((le16_to_cpu((raw_sit)->vblocks) & ~SIT_VBLOCKS_MASK)  \
 350         >> SIT_VBLOCKS_SHIFT)
 351
 352struct f2fs_sit_entry {
 353        __le16 vblocks;                         /* reference above */
 354        __u8 valid_map[SIT_VBLOCK_MAP_SIZE];    /* bitmap for valid blocks */
 355        __le64 mtime;                           /* segment age for cleaning */
 356} __packed;
 357
 358struct f2fs_sit_block {
 359        struct f2fs_sit_entry entries[SIT_ENTRY_PER_BLOCK];
 360} __packed;
 361
 362/*
 363 * For segment summary
 364 *
 365 * One summary block contains exactly 512 summary entries, which represents
 366 * exactly 2MB segment by default. Not allow to change the basic units.
 367 *
 368 * NOTE: For initializing fields, you must use set_summary
 369 *
 370 * - If data page, nid represents dnode's nid
 371 * - If node page, nid represents the node page's nid.
 372 *
 373 * The ofs_in_node is used by only data page. It represents offset
 374 * from node's page's beginning to get a data block address.
 375 * ex) data_blkaddr = (block_t)(nodepage_start_address + ofs_in_node)
 376 */
 377#define ENTRIES_IN_SUM          512
 378#define SUMMARY_SIZE            (7)     /* sizeof(struct summary) */
 379#define SUM_FOOTER_SIZE         (5)     /* sizeof(struct summary_footer) */
 380#define SUM_ENTRY_SIZE          (SUMMARY_SIZE * ENTRIES_IN_SUM)
 381
 382/* a summary entry for a 4KB-sized block in a segment */
 383struct f2fs_summary {
 384        __le32 nid;             /* parent node id */
 385        union {
 386                __u8 reserved[3];
 387                struct {
 388                        __u8 version;           /* node version number */
 389                        __le16 ofs_in_node;     /* block index in parent node */
 390                } __packed;
 391        };
 392} __packed;
 393
 394/* summary block type, node or data, is stored to the summary_footer */
 395#define SUM_TYPE_NODE           (1)
 396#define SUM_TYPE_DATA           (0)
 397
 398struct summary_footer {
 399        unsigned char entry_type;       /* SUM_TYPE_XXX */
 400        __le32 check_sum;               /* summary checksum */
 401} __packed;
 402
 403#define SUM_JOURNAL_SIZE        (F2FS_BLKSIZE - SUM_FOOTER_SIZE -\
 404                                SUM_ENTRY_SIZE)
 405#define NAT_JOURNAL_ENTRIES     ((SUM_JOURNAL_SIZE - 2) /\
 406                                sizeof(struct nat_journal_entry))
 407#define NAT_JOURNAL_RESERVED    ((SUM_JOURNAL_SIZE - 2) %\
 408                                sizeof(struct nat_journal_entry))
 409#define SIT_JOURNAL_ENTRIES     ((SUM_JOURNAL_SIZE - 2) /\
 410                                sizeof(struct sit_journal_entry))
 411#define SIT_JOURNAL_RESERVED    ((SUM_JOURNAL_SIZE - 2) %\
 412                                sizeof(struct sit_journal_entry))
 413
 414/* Reserved area should make size of f2fs_extra_info equals to
 415 * that of nat_journal and sit_journal.
 416 */
 417#define EXTRA_INFO_RESERVED     (SUM_JOURNAL_SIZE - 2 - 8)
 418
 419/*
 420 * frequently updated NAT/SIT entries can be stored in the spare area in
 421 * summary blocks
 422 */
 423enum {
 424        NAT_JOURNAL = 0,
 425        SIT_JOURNAL
 426};
 427
 428struct nat_journal_entry {
 429        __le32 nid;
 430        struct f2fs_nat_entry ne;
 431} __packed;
 432
 433struct nat_journal {
 434        struct nat_journal_entry entries[NAT_JOURNAL_ENTRIES];
 435        __u8 reserved[NAT_JOURNAL_RESERVED];
 436} __packed;
 437
 438struct sit_journal_entry {
 439        __le32 segno;
 440        struct f2fs_sit_entry se;
 441} __packed;
 442
 443struct sit_journal {
 444        struct sit_journal_entry entries[SIT_JOURNAL_ENTRIES];
 445        __u8 reserved[SIT_JOURNAL_RESERVED];
 446} __packed;
 447
 448struct f2fs_extra_info {
 449        __le64 kbytes_written;
 450        __u8 reserved[EXTRA_INFO_RESERVED];
 451} __packed;
 452
 453struct f2fs_journal {
 454        union {
 455                __le16 n_nats;
 456                __le16 n_sits;
 457        };
 458        /* spare area is used by NAT or SIT journals or extra info */
 459        union {
 460                struct nat_journal nat_j;
 461                struct sit_journal sit_j;
 462                struct f2fs_extra_info info;
 463        };
 464} __packed;
 465
 466/* 4KB-sized summary block structure */
 467struct f2fs_summary_block {
 468        struct f2fs_summary entries[ENTRIES_IN_SUM];
 469        struct f2fs_journal journal;
 470        struct summary_footer footer;
 471} __packed;
 472
 473/*
 474 * For directory operations
 475 */
 476#define F2FS_DOT_HASH           0
 477#define F2FS_DDOT_HASH          F2FS_DOT_HASH
 478#define F2FS_MAX_HASH           (~((0x3ULL) << 62))
 479#define F2FS_HASH_COL_BIT       ((0x1ULL) << 63)
 480
 481typedef __le32  f2fs_hash_t;
 482
 483/* One directory entry slot covers 8bytes-long file name */
 484#define F2FS_SLOT_LEN           8
 485#define F2FS_SLOT_LEN_BITS      3
 486
 487#define GET_DENTRY_SLOTS(x) (((x) + F2FS_SLOT_LEN - 1) >> F2FS_SLOT_LEN_BITS)
 488
 489/* MAX level for dir lookup */
 490#define MAX_DIR_HASH_DEPTH      63
 491
 492/* MAX buckets in one level of dir */
 493#define MAX_DIR_BUCKETS         (1 << ((MAX_DIR_HASH_DEPTH / 2) - 1))
 494
 495/*
 496 * space utilization of regular dentry and inline dentry (w/o extra reservation)
 497 *              regular dentry                  inline dentry
 498 * bitmap       1 * 27 = 27                     1 * 23 = 23
 499 * reserved     1 * 3 = 3                       1 * 7 = 7
 500 * dentry       11 * 214 = 2354                 11 * 182 = 2002
 501 * filename     8 * 214 = 1712                  8 * 182 = 1456
 502 * total        4096                            3488
 503 *
 504 * Note: there are more reserved space in inline dentry than in regular
 505 * dentry, when converting inline dentry we should handle this carefully.
 506 */
 507#define NR_DENTRY_IN_BLOCK      214     /* the number of dentry in a block */
 508#define SIZE_OF_DIR_ENTRY       11      /* by byte */
 509#define SIZE_OF_DENTRY_BITMAP   ((NR_DENTRY_IN_BLOCK + BITS_PER_BYTE - 1) / \
 510                                        BITS_PER_BYTE)
 511#define SIZE_OF_RESERVED        (PAGE_SIZE - ((SIZE_OF_DIR_ENTRY + \
 512                                F2FS_SLOT_LEN) * \
 513                                NR_DENTRY_IN_BLOCK + SIZE_OF_DENTRY_BITMAP))
 514
 515/* One directory entry slot representing F2FS_SLOT_LEN-sized file name */
 516struct f2fs_dir_entry {
 517        __le32 hash_code;       /* hash code of file name */
 518        __le32 ino;             /* inode number */
 519        __le16 name_len;        /* lengh of file name */
 520        __u8 file_type;         /* file type */
 521} __packed;
 522
 523/* 4KB-sized directory entry block */
 524struct f2fs_dentry_block {
 525        /* validity bitmap for directory entries in each block */
 526        __u8 dentry_bitmap[SIZE_OF_DENTRY_BITMAP];
 527        __u8 reserved[SIZE_OF_RESERVED];
 528        struct f2fs_dir_entry dentry[NR_DENTRY_IN_BLOCK];
 529        __u8 filename[NR_DENTRY_IN_BLOCK][F2FS_SLOT_LEN];
 530} __packed;
 531
 532/* file types used in inode_info->flags */
 533enum {
 534        F2FS_FT_UNKNOWN,
 535        F2FS_FT_REG_FILE,
 536        F2FS_FT_DIR,
 537        F2FS_FT_CHRDEV,
 538        F2FS_FT_BLKDEV,
 539        F2FS_FT_FIFO,
 540        F2FS_FT_SOCK,
 541        F2FS_FT_SYMLINK,
 542        F2FS_FT_MAX
 543};
 544
 545#define S_SHIFT 12
 546
 547#define F2FS_DEF_PROJID         0       /* default project ID */
 548
 549#endif  /* _LINUX_F2FS_FS_H */
 550