include/linux/f2fs_fs.h

   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_BLK_ALIGN(x)       (((x) + F2FS_BLKSIZE - 1) >> F2FS_BLKSIZE_BITS)
  25
  26 #define NULL_ADDR               ((block_t)0)    /* used as block_t addresses */
  27 #define NEW_ADDR                ((block_t)-1)   /* used as block_t addresses */
  28
  29 #define F2FS_BYTES_TO_BLK(bytes)        ((bytes) >> F2FS_BLKSIZE_BITS)
  30 #define F2FS_BLK_TO_BYTES(blk)          ((blk) << F2FS_BLKSIZE_BITS)
  31
  32 /* 0, 1(node nid), 2(meta nid) are reserved node id */
  33 #define F2FS_RESERVED_NODE_NUM          3
  34
  35 #define F2FS_ROOT_INO(sbi)      ((sbi)->root_ino_num)
  36 #define F2FS_NODE_INO(sbi)      ((sbi)->node_ino_num)
  37 #define F2FS_META_INO(sbi)      ((sbi)->meta_ino_num)
  38
  39 #define F2FS_MAX_QUOTAS         3
  40
  41 #define F2FS_IO_SIZE(sbi)       (1 << (sbi)->write_io_size_bits) /* Blocks */
  42 #define F2FS_IO_SIZE_KB(sbi)    (1 << ((sbi)->write_io_size_bits + 2)) /* KB */
  43 #define F2FS_IO_SIZE_BYTES(sbi) (1 << ((sbi)->write_io_size_bits + 12)) /* B */
  44 #define F2FS_IO_SIZE_BITS(sbi)  ((sbi)->write_io_size_bits) /* power of 2 */
  45 #define F2FS_IO_SIZE_MASK(sbi)  (F2FS_IO_SIZE(sbi) - 1)
  46
  47 /* This flag is used by node and meta inodes, and by recovery */
  48 #define GFP_F2FS_ZERO           (GFP_NOFS | __GFP_ZERO)
  49 #define GFP_F2FS_HIGH_ZERO      (GFP_NOFS | __GFP_ZERO | __GFP_HIGHMEM)
  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  */
  69 struct f2fs_device {
  70         __u8 path[MAX_PATH_LEN];
  71         __le32 total_segments;
  72 } __packed;
  73
  74 struct 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][8];     /* 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 reserved[315];             /* valid reserved region */
 115 } __packed;
 116
 117 /*
 118  * For checkpoint
 119  */
 120 #define CP_NOCRC_RECOVERY_FLAG  0x00000200
 121 #define CP_TRIMMED_FLAG         0x00000100
 122 #define CP_NAT_BITS_FLAG        0x00000080
 123 #define CP_CRC_RECOVERY_FLAG    0x00000040
 124 #define CP_FASTBOOT_FLAG        0x00000020
 125 #define CP_FSCK_FLAG            0x00000010
 126 #define CP_ERROR_FLAG           0x00000008
 127 #define CP_COMPACT_SUM_FLAG     0x00000004
 128 #define CP_ORPHAN_PRESENT_FLAG  0x00000002
 129 #define CP_UMOUNT_FLAG          0x00000001
 130
 131 #define F2FS_CP_PACKS           2       /* # of checkpoint packs */
 132
 133 struct f2fs_checkpoint {
 134         __le64 checkpoint_ver;          /* checkpoint block version number */
 135         __le64 user_block_count;        /* # of user blocks */
 136         __le64 valid_block_count;       /* # of valid blocks in main area */
 137         __le32 rsvd_segment_count;      /* # of reserved segments for gc */
 138         __le32 overprov_segment_count;  /* # of overprovision segments */
 139         __le32 free_segment_count;      /* # of free segments in main area */
 140
 141         /* information of current node segments */
 142         __le32 cur_node_segno[MAX_ACTIVE_NODE_LOGS];
 143         __le16 cur_node_blkoff[MAX_ACTIVE_NODE_LOGS];
 144         /* information of current data segments */
 145         __le32 cur_data_segno[MAX_ACTIVE_DATA_LOGS];
 146         __le16 cur_data_blkoff[MAX_ACTIVE_DATA_LOGS];
 147         __le32 ckpt_flags;              /* Flags : umount and journal_present */
 148         __le32 cp_pack_total_block_count;       /* total # of one cp pack */
 149         __le32 cp_pack_start_sum;       /* start block number of data summary */
 150         __le32 valid_node_count;        /* Total number of valid nodes */
 151         __le32 valid_inode_count;       /* Total number of valid inodes */
 152         __le32 next_free_nid;           /* Next free node number */
 153         __le32 sit_ver_bitmap_bytesize; /* Default value 64 */
 154         __le32 nat_ver_bitmap_bytesize; /* Default value 256 */
 155         __le32 checksum_offset;         /* checksum offset inside cp block */
 156         __le64 elapsed_time;            /* mounted time */
 157         /* allocation type of current segment */
 158         unsigned char alloc_type[MAX_ACTIVE_LOGS];
 159
 160         /* SIT and NAT version bitmap */
 161         unsigned char sit_nat_version_bitmap[1];
 162 } __packed;
 163
 164 /*
 165  * For orphan inode management
 166  */
 167 #define F2FS_ORPHANS_PER_BLOCK  1020
 168
 169 #define GET_ORPHAN_BLOCKS(n)    (((n) + F2FS_ORPHANS_PER_BLOCK - 1) / \
 170                                         F2FS_ORPHANS_PER_BLOCK)
 171
 172 struct f2fs_orphan_block {
 173         __le32 ino[F2FS_ORPHANS_PER_BLOCK];     /* inode numbers */
 174         __le32 reserved;        /* reserved */
 175         __le16 blk_addr;        /* block index in current CP */
 176         __le16 blk_count;       /* Number of orphan inode blocks in CP */
 177         __le32 entry_count;     /* Total number of orphan nodes in current CP */
 178         __le32 check_sum;       /* CRC32 for orphan inode block */
 179 } __packed;
 180
 181 /*
 182  * For NODE structure
 183  */
 184 struct f2fs_extent {
 185         __le32 fofs;            /* start file offset of the extent */
 186         __le32 blk;             /* start block address of the extent */
 187         __le32 len;             /* lengh of the extent */
 188 } __packed;
 189
 190 #define F2FS_NAME_LEN           255
 191 /* 200 bytes for inline xattrs by default */
 192 #define DEFAULT_INLINE_XATTR_ADDRS      50
 193 #define DEF_ADDRS_PER_INODE     923     /* Address Pointers in an Inode */
 194 #define CUR_ADDRS_PER_INODE(inode)      (DEF_ADDRS_PER_INODE - \
 195                                         get_extra_isize(inode))
 196 #define DEF_NIDS_PER_INODE      5       /* Node IDs in an Inode */
 197 #define ADDRS_PER_INODE(inode)  addrs_per_inode(inode)
 198 #define ADDRS_PER_BLOCK         1018    /* Address Pointers in a Direct Block */
 199 #define NIDS_PER_BLOCK          1018    /* Node IDs in an Indirect Block */
 200
 201 #define ADDRS_PER_PAGE(page, inode)     \
 202         (IS_INODE(page) ? ADDRS_PER_INODE(inode) : ADDRS_PER_BLOCK)
 203
 204 #define NODE_DIR1_BLOCK         (DEF_ADDRS_PER_INODE + 1)
 205 #define NODE_DIR2_BLOCK         (DEF_ADDRS_PER_INODE + 2)
 206 #define NODE_IND1_BLOCK         (DEF_ADDRS_PER_INODE + 3)
 207 #define NODE_IND2_BLOCK         (DEF_ADDRS_PER_INODE + 4)
 208 #define NODE_DIND_BLOCK         (DEF_ADDRS_PER_INODE + 5)
 209
 210 #define F2FS_INLINE_XATTR       0x01    /* file inline xattr flag */
 211 #define F2FS_INLINE_DATA        0x02    /* file inline data flag */
 212 #define F2FS_INLINE_DENTRY      0x04    /* file inline dentry flag */
 213 #define F2FS_DATA_EXIST         0x08    /* file inline data exist flag */
 214 #define F2FS_INLINE_DOTS        0x10    /* file having implicit dot dentries */
 215 #define F2FS_EXTRA_ATTR         0x20    /* file having extra attribute */
 216 #define F2FS_PIN_FILE           0x40    /* file should not be gced */
 217
 218 struct f2fs_inode {
 219         __le16 i_mode;                  /* file mode */
 220         __u8 i_advise;                  /* file hints */
 221         __u8 i_inline;                  /* file inline flags */
 222         __le32 i_uid;                   /* user ID */
 223         __le32 i_gid;                   /* group ID */
 224         __le32 i_links;                 /* links count */
 225         __le64 i_size;                  /* file size in bytes */
 226         __le64 i_blocks;                /* file size in blocks */
 227         __le64 i_atime;                 /* access time */
 228         __le64 i_ctime;                 /* change time */
 229         __le64 i_mtime;                 /* modification time */
 230         __le32 i_atime_nsec;            /* access time in nano scale */
 231         __le32 i_ctime_nsec;            /* change time in nano scale */
 232         __le32 i_mtime_nsec;            /* modification time in nano scale */
 233         __le32 i_generation;            /* file version (for NFS) */
 234         union {
 235                 __le32 i_current_depth; /* only for directory depth */
 236                 __le16 i_gc_failures;   /*
 237                                          * # of gc failures on pinned file.
 238                                          * only for regular files.
 239                                          */
 240         };
 241         __le32 i_xattr_nid;             /* nid to save xattr */
 242         __le32 i_flags;                 /* file attributes */
 243         __le32 i_pino;                  /* parent inode number */
 244         __le32 i_namelen;               /* file name length */
 245         __u8 i_name[F2FS_NAME_LEN];     /* file name for SPOR */
 246         __u8 i_dir_level;               /* dentry_level for large dir */
 247
 248         struct f2fs_extent i_ext;       /* caching a largest extent */
 249
 250         union {
 251                 struct {
 252                         __le16 i_extra_isize;   /* extra inode attribute size */
 253                         __le16 i_inline_xattr_size;     /* inline xattr size, unit: 4 bytes */
 254                         __le32 i_projid;        /* project id */
 255                         __le32 i_inode_checksum;/* inode meta checksum */
 256                         __le64 i_crtime;        /* creation time */
 257                         __le32 i_crtime_nsec;   /* creation time in nano scale */
 258                         __le32 i_extra_end[0];  /* for attribute size calculation */
 259                 } __packed;
 260                 __le32 i_addr[DEF_ADDRS_PER_INODE];     /* Pointers to data blocks */
 261         };
 262         __le32 i_nid[DEF_NIDS_PER_INODE];       /* direct(2), indirect(2),
 263                                                 double_indirect(1) node id */
 264 } __packed;
 265
 266 struct direct_node {
 267         __le32 addr[ADDRS_PER_BLOCK];   /* array of data block address */
 268 } __packed;
 269
 270 struct indirect_node {
 271         __le32 nid[NIDS_PER_BLOCK];     /* array of data block address */
 272 } __packed;
 273
 274 enum {
 275         COLD_BIT_SHIFT = 0,
 276         FSYNC_BIT_SHIFT,
 277         DENT_BIT_SHIFT,
 278         OFFSET_BIT_SHIFT
 279 };
 280
 281 #define OFFSET_BIT_MASK         (0x07)  /* (0x01 << OFFSET_BIT_SHIFT) - 1 */
 282
 283 struct node_footer {
 284         __le32 nid;             /* node id */
 285         __le32 ino;             /* inode nunmber */
 286         __le32 flag;            /* include cold/fsync/dentry marks and offset */
 287         __le64 cp_ver;          /* checkpoint version */
 288         __le32 next_blkaddr;    /* next node page block address */
 289 } __packed;
 290
 291 struct f2fs_node {
 292         /* can be one of three types: inode, direct, and indirect types */
 293         union {
 294                 struct f2fs_inode i;
 295                 struct direct_node dn;
 296                 struct indirect_node in;
 297         };
 298         struct node_footer footer;
 299 } __packed;
 300
 301 /*
 302  * For NAT entries
 303  */
 304 #define NAT_ENTRY_PER_BLOCK (PAGE_SIZE / sizeof(struct f2fs_nat_entry))
 305 #define NAT_ENTRY_BITMAP_SIZE   ((NAT_ENTRY_PER_BLOCK + 7) / 8)
 306
 307 struct f2fs_nat_entry {
 308         __u8 version;           /* latest version of cached nat entry */
 309         __le32 ino;             /* inode number */
 310         __le32 block_addr;      /* block address */
 311 } __packed;
 312
 313 struct f2fs_nat_block {
 314         struct f2fs_nat_entry entries[NAT_ENTRY_PER_BLOCK];
 315 } __packed;
 316
 317 /*
 318  * For SIT entries
 319  *
 320  * Each segment is 2MB in size by default so that a bitmap for validity of
 321  * there-in blocks should occupy 64 bytes, 512 bits.
 322  * Not allow to change this.
 323  */
 324 #define SIT_VBLOCK_MAP_SIZE 64
 325 #define SIT_ENTRY_PER_BLOCK (PAGE_SIZE / sizeof(struct f2fs_sit_entry))
 326
 327 /*
 328  * F2FS uses 4 bytes to represent block address. As a result, supported size of
 329  * disk is 16 TB and it equals to 16 * 1024 * 1024 / 2 segments.
 330  */
 331 #define F2FS_MAX_SEGMENT       ((16 * 1024 * 1024) / 2)
 332
 333 /*
 334  * Note that f2fs_sit_entry->vblocks has the following bit-field information.
 335  * [15:10] : allocation type such as CURSEG_XXXX_TYPE
 336  * [9:0] : valid block count
 337  */
 338 #define SIT_VBLOCKS_SHIFT       10
 339 #define SIT_VBLOCKS_MASK        ((1 << SIT_VBLOCKS_SHIFT) - 1)
 340 #define GET_SIT_VBLOCKS(raw_sit)                                \
 341         (le16_to_cpu((raw_sit)->vblocks) & SIT_VBLOCKS_MASK)
 342 #define GET_SIT_TYPE(raw_sit)                                   \
 343         ((le16_to_cpu((raw_sit)->vblocks) & ~SIT_VBLOCKS_MASK)  \
 344          >> SIT_VBLOCKS_SHIFT)
 345
 346 struct f2fs_sit_entry {
 347         __le16 vblocks;                         /* reference above */
 348         __u8 valid_map[SIT_VBLOCK_MAP_SIZE];    /* bitmap for valid blocks */
 349         __le64 mtime;                           /* segment age for cleaning */
 350 } __packed;
 351
 352 struct f2fs_sit_block {
 353         struct f2fs_sit_entry entries[SIT_ENTRY_PER_BLOCK];
 354 } __packed;
 355
 356 /*
 357  * For segment summary
 358  *
 359  * One summary block contains exactly 512 summary entries, which represents
 360  * exactly 2MB segment by default. Not allow to change the basic units.
 361  *
 362  * NOTE: For initializing fields, you must use set_summary
 363  *
 364  * - If data page, nid represents dnode's nid
 365  * - If node page, nid represents the node page's nid.
 366  *
 367  * The ofs_in_node is used by only data page. It represents offset
 368  * from node's page's beginning to get a data block address.
 369  * ex) data_blkaddr = (block_t)(nodepage_start_address + ofs_in_node)
 370  */
 371 #define ENTRIES_IN_SUM          512
 372 #define SUMMARY_SIZE            (7)     /* sizeof(struct summary) */
 373 #define SUM_FOOTER_SIZE         (5)     /* sizeof(struct summary_footer) */
 374 #define SUM_ENTRY_SIZE          (SUMMARY_SIZE * ENTRIES_IN_SUM)
 375
 376 /* a summary entry for a 4KB-sized block in a segment */
 377 struct f2fs_summary {
 378         __le32 nid;             /* parent node id */
 379         union {
 380                 __u8 reserved[3];
 381                 struct {
 382                         __u8 version;           /* node version number */
 383                         __le16 ofs_in_node;     /* block index in parent node */
 384                 } __packed;
 385         };
 386 } __packed;
 387
 388 /* summary block type, node or data, is stored to the summary_footer */
 389 #define SUM_TYPE_NODE           (1)
 390 #define SUM_TYPE_DATA           (0)
 391
 392 struct summary_footer {
 393         unsigned char entry_type;       /* SUM_TYPE_XXX */
 394         __le32 check_sum;               /* summary checksum */
 395 } __packed;
 396
 397 #define SUM_JOURNAL_SIZE        (F2FS_BLKSIZE - SUM_FOOTER_SIZE -\
 398                                 SUM_ENTRY_SIZE)
 399 #define NAT_JOURNAL_ENTRIES     ((SUM_JOURNAL_SIZE - 2) /\
 400                                 sizeof(struct nat_journal_entry))
 401 #define NAT_JOURNAL_RESERVED    ((SUM_JOURNAL_SIZE - 2) %\
 402                                 sizeof(struct nat_journal_entry))
 403 #define SIT_JOURNAL_ENTRIES     ((SUM_JOURNAL_SIZE - 2) /\
 404                                 sizeof(struct sit_journal_entry))
 405 #define SIT_JOURNAL_RESERVED    ((SUM_JOURNAL_SIZE - 2) %\
 406                                 sizeof(struct sit_journal_entry))
 407
 408 /* Reserved area should make size of f2fs_extra_info equals to
 409  * that of nat_journal and sit_journal.
 410  */
 411 #define EXTRA_INFO_RESERVED     (SUM_JOURNAL_SIZE - 2 - 8)
 412
 413 /*
 414  * frequently updated NAT/SIT entries can be stored in the spare area in
 415  * summary blocks
 416  */
 417 enum {
 418         NAT_JOURNAL = 0,
 419         SIT_JOURNAL
 420 };
 421
 422 struct nat_journal_entry {
 423         __le32 nid;
 424         struct f2fs_nat_entry ne;
 425 } __packed;
 426
 427 struct nat_journal {
 428         struct nat_journal_entry entries[NAT_JOURNAL_ENTRIES];
 429         __u8 reserved[NAT_JOURNAL_RESERVED];
 430 } __packed;
 431
 432 struct sit_journal_entry {
 433         __le32 segno;
 434         struct f2fs_sit_entry se;
 435 } __packed;
 436
 437 struct sit_journal {
 438         struct sit_journal_entry entries[SIT_JOURNAL_ENTRIES];
 439         __u8 reserved[SIT_JOURNAL_RESERVED];
 440 } __packed;
 441
 442 struct f2fs_extra_info {
 443         __le64 kbytes_written;
 444         __u8 reserved[EXTRA_INFO_RESERVED];
 445 } __packed;
 446
 447 struct f2fs_journal {
 448         union {
 449                 __le16 n_nats;
 450                 __le16 n_sits;
 451         };
 452         /* spare area is used by NAT or SIT journals or extra info */
 453         union {
 454                 struct nat_journal nat_j;
 455                 struct sit_journal sit_j;
 456                 struct f2fs_extra_info info;
 457         };
 458 } __packed;
 459
 460 /* 4KB-sized summary block structure */
 461 struct f2fs_summary_block {
 462         struct f2fs_summary entries[ENTRIES_IN_SUM];
 463         struct f2fs_journal journal;
 464         struct summary_footer footer;
 465 } __packed;
 466
 467 /*
 468  * For directory operations
 469  */
 470 #define F2FS_DOT_HASH           0
 471 #define F2FS_DDOT_HASH          F2FS_DOT_HASH
 472 #define F2FS_MAX_HASH           (~((0x3ULL) << 62))
 473 #define F2FS_HASH_COL_BIT       ((0x1ULL) << 63)
 474
 475 typedef __le32  f2fs_hash_t;
 476
 477 /* One directory entry slot covers 8bytes-long file name */
 478 #define F2FS_SLOT_LEN           8
 479 #define F2FS_SLOT_LEN_BITS      3
 480
 481 #define GET_DENTRY_SLOTS(x) (((x) + F2FS_SLOT_LEN - 1) >> F2FS_SLOT_LEN_BITS)
 482
 483 /* MAX level for dir lookup */
 484 #define MAX_DIR_HASH_DEPTH      63
 485
 486 /* MAX buckets in one level of dir */
 487 #define MAX_DIR_BUCKETS         (1 << ((MAX_DIR_HASH_DEPTH / 2) - 1))
 488
 489 /*
 490  * space utilization of regular dentry and inline dentry (w/o extra reservation)
 491  *              regular dentry                  inline dentry
 492  * bitmap       1 * 27 = 27                     1 * 23 = 23
 493  * reserved     1 * 3 = 3                       1 * 7 = 7
 494  * dentry       11 * 214 = 2354                 11 * 182 = 2002
 495  * filename     8 * 214 = 1712                  8 * 182 = 1456
 496  * total        4096                            3488
 497  *
 498  * Note: there are more reserved space in inline dentry than in regular
 499  * dentry, when converting inline dentry we should handle this carefully.
 500  */
 501 #define NR_DENTRY_IN_BLOCK      214     /* the number of dentry in a block */
 502 #define SIZE_OF_DIR_ENTRY       11      /* by byte */
 503 #define SIZE_OF_DENTRY_BITMAP   ((NR_DENTRY_IN_BLOCK + BITS_PER_BYTE - 1) / \
 504                                         BITS_PER_BYTE)
 505 #define SIZE_OF_RESERVED        (PAGE_SIZE - ((SIZE_OF_DIR_ENTRY + \
 506                                 F2FS_SLOT_LEN) * \
 507                                 NR_DENTRY_IN_BLOCK + SIZE_OF_DENTRY_BITMAP))
 508
 509 /* One directory entry slot representing F2FS_SLOT_LEN-sized file name */
 510 struct f2fs_dir_entry {
 511         __le32 hash_code;       /* hash code of file name */
 512         __le32 ino;             /* inode number */
 513         __le16 name_len;        /* lengh of file name */
 514         __u8 file_type;         /* file type */
 515 } __packed;
 516
 517 /* 4KB-sized directory entry block */
 518 struct f2fs_dentry_block {
 519         /* validity bitmap for directory entries in each block */
 520         __u8 dentry_bitmap[SIZE_OF_DENTRY_BITMAP];
 521         __u8 reserved[SIZE_OF_RESERVED];
 522         struct f2fs_dir_entry dentry[NR_DENTRY_IN_BLOCK];
 523         __u8 filename[NR_DENTRY_IN_BLOCK][F2FS_SLOT_LEN];
 524 } __packed;
 525
 526 /* file types used in inode_info->flags */
 527 enum {
 528         F2FS_FT_UNKNOWN,
 529         F2FS_FT_REG_FILE,
 530         F2FS_FT_DIR,
 531         F2FS_FT_CHRDEV,
 532         F2FS_FT_BLKDEV,
 533         F2FS_FT_FIFO,
 534         F2FS_FT_SOCK,
 535         F2FS_FT_SYMLINK,
 536         F2FS_FT_MAX
 537 };
 538
 539 #define S_SHIFT 12
 540
 541 #define F2FS_DEF_PROJID         0       /* default project ID */
 542
 543 #endif  /* _LINUX_F2FS_FS_H */