root/include/uapi/linux/nilfs2_ondisk.h
/* SPDX-License-Identifier: LGPL-2.1+ WITH Linux-syscall-note */
/*
 * nilfs2_ondisk.h - NILFS2 on-disk structures
 *
 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 */
/*
 *  linux/include/linux/ext2_fs.h
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/include/linux/minix_fs.h
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#ifndef _LINUX_NILFS2_ONDISK_H
#define _LINUX_NILFS2_ONDISK_H

#include <linux/types.h>
#include <linux/magic.h>
#include <asm/byteorder.h>

#define NILFS_INODE_BMAP_SIZE   7

/**
 * struct nilfs_inode - structure of an inode on disk
 * @i_blocks: blocks count
 * @i_size: size in bytes
 * @i_ctime: creation time (seconds)
 * @i_mtime: modification time (seconds)
 * @i_ctime_nsec: creation time (nano seconds)
 * @i_mtime_nsec: modification time (nano seconds)
 * @i_uid: user id
 * @i_gid: group id
 * @i_mode: file mode
 * @i_links_count: links count
 * @i_flags: file flags
 * @i_bmap: block mapping
 * @i_xattr: extended attributes
 * @i_generation: file generation (for NFS)
 * @i_pad: padding
 */
struct nilfs_inode {
        __le64  i_blocks;
        __le64  i_size;
        __le64  i_ctime;
        __le64  i_mtime;
        __le32  i_ctime_nsec;
        __le32  i_mtime_nsec;
        __le32  i_uid;
        __le32  i_gid;
        __le16  i_mode;
        __le16  i_links_count;
        __le32  i_flags;
        __le64  i_bmap[NILFS_INODE_BMAP_SIZE];
#define i_device_code   i_bmap[0]
        __le64  i_xattr;
        __le32  i_generation;
        __le32  i_pad;
};

#define NILFS_MIN_INODE_SIZE            128

/**
 * struct nilfs_super_root - structure of super root
 * @sr_sum: check sum
 * @sr_bytes: byte count of the structure
 * @sr_flags: flags (reserved)
 * @sr_nongc_ctime: write time of the last segment not for cleaner operation
 * @sr_dat: DAT file inode
 * @sr_cpfile: checkpoint file inode
 * @sr_sufile: segment usage file inode
 */
struct nilfs_super_root {
        __le32 sr_sum;
        __le16 sr_bytes;
        __le16 sr_flags;
        __le64 sr_nongc_ctime;
        struct nilfs_inode sr_dat;
        struct nilfs_inode sr_cpfile;
        struct nilfs_inode sr_sufile;
};

#define NILFS_SR_MDT_OFFSET(inode_size, i)  \
        ((unsigned long)&((struct nilfs_super_root *)0)->sr_dat + \
                        (inode_size) * (i))
#define NILFS_SR_DAT_OFFSET(inode_size)     NILFS_SR_MDT_OFFSET(inode_size, 0)
#define NILFS_SR_CPFILE_OFFSET(inode_size)  NILFS_SR_MDT_OFFSET(inode_size, 1)
#define NILFS_SR_SUFILE_OFFSET(inode_size)  NILFS_SR_MDT_OFFSET(inode_size, 2)
#define NILFS_SR_BYTES(inode_size)          NILFS_SR_MDT_OFFSET(inode_size, 3)

/*
 * Maximal mount counts
 */
#define NILFS_DFL_MAX_MNT_COUNT         50      /* 50 mounts */

/*
 * File system states (sbp->s_state, nilfs->ns_mount_state)
 */
#define NILFS_VALID_FS                  0x0001  /* Unmounted cleanly */
#define NILFS_ERROR_FS                  0x0002  /* Errors detected */
#define NILFS_RESIZE_FS                 0x0004  /* Resize required */

/*
 * Mount flags (sbi->s_mount_opt)
 */
#define NILFS_MOUNT_ERROR_MODE          0x0070  /* Error mode mask */
#define NILFS_MOUNT_ERRORS_CONT         0x0010  /* Continue on errors */
#define NILFS_MOUNT_ERRORS_RO           0x0020  /* Remount fs ro on errors */
#define NILFS_MOUNT_ERRORS_PANIC        0x0040  /* Panic on errors */
#define NILFS_MOUNT_BARRIER             0x1000  /* Use block barriers */
#define NILFS_MOUNT_STRICT_ORDER        0x2000  /*
                                                 * Apply strict in-order
                                                 * semantics also for data
                                                 */
#define NILFS_MOUNT_NORECOVERY          0x4000  /*
                                                 * Disable write access during
                                                 * mount-time recovery
                                                 */
#define NILFS_MOUNT_DISCARD             0x8000  /* Issue DISCARD requests */


/**
 * struct nilfs_super_block - structure of super block on disk
 * @s_rev_level:                Revision level
 * @s_minor_rev_level:          minor revision level
 * @s_magic:                    Magic signature
 * @s_bytes:                    Bytes count of CRC calculation for
 *                                this structure.  s_reserved is excluded.
 * @s_flags:                    flags
 * @s_crc_seed:                 Seed value of CRC calculation
 * @s_sum:                      Check sum of super block
 * @s_log_block_size:           Block size represented as follows:
 *                                blocksize = 1 << (s_log_block_size + 10)
 * @s_nsegments:                Number of segments in filesystem
 * @s_dev_size:                 block device size in bytes
 * @s_first_data_block:         1st seg disk block number
 * @s_blocks_per_segment:       number of blocks per full segment
 * @s_r_segments_percentage:    Reserved segments percentage
 * @s_last_cno:                 Last checkpoint number
 * @s_last_pseg:                disk block addr pseg written last
 * @s_last_seq:                 seq. number of seg written last
 * @s_free_blocks_count:        Free blocks count
 * @s_ctime:                    Creation time (execution time of newfs)
 * @s_mtime:                    Mount time
 * @s_wtime:                    Write time
 * @s_mnt_count:                Mount count
 * @s_max_mnt_count:            Maximal mount count
 * @s_state:                    File system state
 * @s_errors:                   Behaviour when detecting errors
 * @s_lastcheck:                time of last check
 * @s_checkinterval:            max. time between checks
 * @s_creator_os:               OS
 * @s_def_resuid:               Default uid for reserved blocks
 * @s_def_resgid:               Default gid for reserved blocks
 * @s_first_ino:                First non-reserved inode
 * @s_inode_size:               Size of an inode
 * @s_dat_entry_size:           Size of a dat entry
 * @s_checkpoint_size:          Size of a checkpoint
 * @s_segment_usage_size:       Size of a segment usage
 * @s_uuid:                     128-bit uuid for volume
 * @s_volume_name:              volume name
 * @s_c_interval:               Commit interval of segment
 * @s_c_block_max:              Threshold of data amount for the
 *                                segment construction
 * @s_feature_compat:           Compatible feature set
 * @s_feature_compat_ro:        Read-only compatible feature set
 * @s_feature_incompat:         Incompatible feature set
 * @s_reserved:                 padding to the end of the block
 */
struct nilfs_super_block {
/*00*/  __le32  s_rev_level;
        __le16  s_minor_rev_level;
        __le16  s_magic;

        __le16  s_bytes;
        __le16  s_flags;
        __le32  s_crc_seed;
/*10*/  __le32  s_sum;

        __le32  s_log_block_size;
        __le64  s_nsegments;
/*20*/  __le64  s_dev_size;
        __le64  s_first_data_block;
/*30*/  __le32  s_blocks_per_segment;
        __le32  s_r_segments_percentage;

        __le64  s_last_cno;
/*40*/  __le64  s_last_pseg;
        __le64  s_last_seq;
/*50*/  __le64  s_free_blocks_count;

        __le64  s_ctime;
/*60*/  __le64  s_mtime;
        __le64  s_wtime;
/*70*/  __le16  s_mnt_count;
        __le16  s_max_mnt_count;
        __le16  s_state;
        __le16  s_errors;
        __le64  s_lastcheck;

/*80*/  __le32  s_checkinterval;
        __le32  s_creator_os;
        __le16  s_def_resuid;
        __le16  s_def_resgid;
        __le32  s_first_ino;

/*90*/  __le16  s_inode_size;
        __le16  s_dat_entry_size;
        __le16  s_checkpoint_size;
        __le16  s_segment_usage_size;

/*98*/  __u8    s_uuid[16];
/*A8*/  char    s_volume_name[80]       __kernel_nonstring;

/*F8*/  __le32  s_c_interval;
        __le32  s_c_block_max;

/*100*/ __le64  s_feature_compat;
        __le64  s_feature_compat_ro;
        __le64  s_feature_incompat;
        __u32   s_reserved[186];
};

/*
 * Codes for operating systems
 */
#define NILFS_OS_LINUX          0
/* Codes from 1 to 4 are reserved to keep compatibility with ext2 creator-OS */

/*
 * Revision levels
 */
#define NILFS_CURRENT_REV       2       /* current major revision */
#define NILFS_MINOR_REV         0       /* minor revision */
#define NILFS_MIN_SUPP_REV      2       /* minimum supported revision */

/*
 * Feature set definitions
 *
 * If there is a bit set in the incompatible feature set that the kernel
 * doesn't know about, it should refuse to mount the filesystem.
 */
#define NILFS_FEATURE_COMPAT_RO_BLOCK_COUNT     0x00000001ULL

#define NILFS_FEATURE_COMPAT_SUPP       0ULL
#define NILFS_FEATURE_COMPAT_RO_SUPP    NILFS_FEATURE_COMPAT_RO_BLOCK_COUNT
#define NILFS_FEATURE_INCOMPAT_SUPP     0ULL

/*
 * Bytes count of super_block for CRC-calculation
 */
#define NILFS_SB_BYTES  \
        ((long)&((struct nilfs_super_block *)0)->s_reserved)

/*
 * Special inode number
 */
#define NILFS_ROOT_INO          2       /* Root file inode */
#define NILFS_DAT_INO           3       /* DAT file */
#define NILFS_CPFILE_INO        4       /* checkpoint file */
#define NILFS_SUFILE_INO        5       /* segment usage file */
#define NILFS_IFILE_INO         6       /* ifile */
#define NILFS_ATIME_INO         7       /* Atime file (reserved) */
#define NILFS_XATTR_INO         8       /* Xattribute file (reserved) */
#define NILFS_SKETCH_INO        10      /* Sketch file */
#define NILFS_USER_INO          11      /* Fisrt user's file inode number */

#define NILFS_SB_OFFSET_BYTES   1024    /* byte offset of nilfs superblock */

#define NILFS_SEG_MIN_BLOCKS    16      /*
                                         * Minimum number of blocks in
                                         * a full segment
                                         */
#define NILFS_PSEG_MIN_BLOCKS   2       /*
                                         * Minimum number of blocks in
                                         * a partial segment
                                         */
#define NILFS_MIN_NRSVSEGS      8       /*
                                         * Minimum number of reserved
                                         * segments
                                         */

/*
 * We call DAT, cpfile, and sufile root metadata files.  Inodes of
 * these files are written in super root block instead of ifile, and
 * garbage collector doesn't keep any past versions of these files.
 */
#define NILFS_ROOT_METADATA_FILE(ino) \
        ((ino) >= NILFS_DAT_INO && (ino) <= NILFS_SUFILE_INO)

/*
 * bytes offset of secondary super block
 */
#define NILFS_SB2_OFFSET_BYTES(devsize) ((((devsize) >> 12) - 1) << 12)

/*
 * Maximal count of links to a file
 */
#define NILFS_LINK_MAX          32000

/*
 * Structure of a directory entry
 *  (Same as ext2)
 */

#define NILFS_NAME_LEN 255

/*
 * Block size limitations
 */
#define NILFS_MIN_BLOCK_SIZE            1024
#define NILFS_MAX_BLOCK_SIZE            65536

/*
 * The new version of the directory entry.  Since V0 structures are
 * stored in intel byte order, and the name_len field could never be
 * bigger than 255 chars, it's safe to reclaim the extra byte for the
 * file_type field.
 */
struct nilfs_dir_entry {
        __le64  inode;                  /* Inode number */
        __le16  rec_len;                /* Directory entry length */
        __u8    name_len;               /* Name length */
        __u8    file_type;              /* Dir entry type (file, dir, etc) */
        char    name[NILFS_NAME_LEN];   /* File name */
        char    pad;
};

/*
 * NILFS directory file types.  Only the low 3 bits are used.  The
 * other bits are reserved for now.
 */
enum {
        NILFS_FT_UNKNOWN,
        NILFS_FT_REG_FILE,
        NILFS_FT_DIR,
        NILFS_FT_CHRDEV,
        NILFS_FT_BLKDEV,
        NILFS_FT_FIFO,
        NILFS_FT_SOCK,
        NILFS_FT_SYMLINK,
        NILFS_FT_MAX
};

/*
 * NILFS_DIR_PAD defines the directory entries boundaries
 *
 * NOTE: It must be a multiple of 8
 */
#define NILFS_DIR_PAD                   8
#define NILFS_DIR_ROUND                 (NILFS_DIR_PAD - 1)
#define NILFS_DIR_REC_LEN(name_len)     (((name_len) + 12 + NILFS_DIR_ROUND) & \
                                        ~NILFS_DIR_ROUND)
#define NILFS_MAX_REC_LEN               ((1 << 16) - 1)

/**
 * struct nilfs_finfo - file information
 * @fi_ino: inode number
 * @fi_cno: checkpoint number
 * @fi_nblocks: number of blocks (including intermediate blocks)
 * @fi_ndatablk: number of file data blocks
 */
struct nilfs_finfo {
        __le64 fi_ino;
        __le64 fi_cno;
        __le32 fi_nblocks;
        __le32 fi_ndatablk;
};

/**
 * struct nilfs_binfo_v - information on a data block (except DAT)
 * @bi_vblocknr: virtual block number
 * @bi_blkoff: block offset
 */
struct nilfs_binfo_v {
        __le64 bi_vblocknr;
        __le64 bi_blkoff;
};

/**
 * struct nilfs_binfo_dat - information on a DAT node block
 * @bi_blkoff: block offset
 * @bi_level: level
 * @bi_pad: padding
 */
struct nilfs_binfo_dat {
        __le64 bi_blkoff;
        __u8 bi_level;
        __u8 bi_pad[7];
};

/**
 * union nilfs_binfo: block information
 * @bi_v: nilfs_binfo_v structure
 * @bi_dat: nilfs_binfo_dat structure
 */
union nilfs_binfo {
        struct nilfs_binfo_v bi_v;
        struct nilfs_binfo_dat bi_dat;
};

/**
 * struct nilfs_segment_summary - segment summary header
 * @ss_datasum: checksum of data
 * @ss_sumsum: checksum of segment summary
 * @ss_magic: magic number
 * @ss_bytes: size of this structure in bytes
 * @ss_flags: flags
 * @ss_seq: sequence number
 * @ss_create: creation timestamp
 * @ss_next: next segment
 * @ss_nblocks: number of blocks
 * @ss_nfinfo: number of finfo structures
 * @ss_sumbytes: total size of segment summary in bytes
 * @ss_pad: padding
 * @ss_cno: checkpoint number
 */
struct nilfs_segment_summary {
        __le32 ss_datasum;
        __le32 ss_sumsum;
        __le32 ss_magic;
        __le16 ss_bytes;
        __le16 ss_flags;
        __le64 ss_seq;
        __le64 ss_create;
        __le64 ss_next;
        __le32 ss_nblocks;
        __le32 ss_nfinfo;
        __le32 ss_sumbytes;
        __le32 ss_pad;
        __le64 ss_cno;
        /* array of finfo structures */
};

#define NILFS_SEGSUM_MAGIC      0x1eaffa11  /* segment summary magic number */

/*
 * Segment summary flags
 */
#define NILFS_SS_LOGBGN 0x0001  /* begins a logical segment */
#define NILFS_SS_LOGEND 0x0002  /* ends a logical segment */
#define NILFS_SS_SR     0x0004  /* has super root */
#define NILFS_SS_SYNDT  0x0008  /* includes data only updates */
#define NILFS_SS_GC     0x0010  /* segment written for cleaner operation */

/**
 * struct nilfs_btree_node - header of B-tree node block
 * @bn_flags: flags
 * @bn_level: level
 * @bn_nchildren: number of children
 * @bn_pad: padding
 */
struct nilfs_btree_node {
        __u8 bn_flags;
        __u8 bn_level;
        __le16 bn_nchildren;
        __le32 bn_pad;
};

/* flags */
#define NILFS_BTREE_NODE_ROOT   0x01

/* level */
#define NILFS_BTREE_LEVEL_DATA          0
#define NILFS_BTREE_LEVEL_NODE_MIN      (NILFS_BTREE_LEVEL_DATA + 1)
#define NILFS_BTREE_LEVEL_MAX           14      /* Max level (exclusive) */

/**
 * struct nilfs_direct_node - header of built-in bmap array
 * @dn_flags: flags
 * @pad: padding
 */
struct nilfs_direct_node {
        __u8 dn_flags;
        __u8 pad[7];
};

/**
 * struct nilfs_palloc_group_desc - block group descriptor
 * @pg_nfrees: number of free entries in block group
 */
struct nilfs_palloc_group_desc {
        __le32 pg_nfrees;
};

/**
 * struct nilfs_dat_entry - disk address translation entry
 * @de_blocknr: block number
 * @de_start: start checkpoint number
 * @de_end: end checkpoint number
 * @de_rsv: reserved for future use
 */
struct nilfs_dat_entry {
        __le64 de_blocknr;
        __le64 de_start;
        __le64 de_end;
        __le64 de_rsv;
};

#define NILFS_MIN_DAT_ENTRY_SIZE        32

/**
 * struct nilfs_snapshot_list - snapshot list
 * @ssl_next: next checkpoint number on snapshot list
 * @ssl_prev: previous checkpoint number on snapshot list
 */
struct nilfs_snapshot_list {
        __le64 ssl_next;
        __le64 ssl_prev;
};

/**
 * struct nilfs_checkpoint - checkpoint structure
 * @cp_flags: flags
 * @cp_checkpoints_count: checkpoints count in a block
 * @cp_snapshot_list: snapshot list
 * @cp_cno: checkpoint number
 * @cp_create: creation timestamp
 * @cp_nblk_inc: number of blocks incremented by this checkpoint
 * @cp_inodes_count: inodes count
 * @cp_blocks_count: blocks count
 * @cp_ifile_inode: inode of ifile
 */
struct nilfs_checkpoint {
        __le32 cp_flags;
        __le32 cp_checkpoints_count;
        struct nilfs_snapshot_list cp_snapshot_list;
        __le64 cp_cno;
        __le64 cp_create;
        __le64 cp_nblk_inc;
        __le64 cp_inodes_count;
        __le64 cp_blocks_count;

        /*
         * Do not change the byte offset of ifile inode.
         * To keep the compatibility of the disk format,
         * additional fields should be added behind cp_ifile_inode.
         */
        struct nilfs_inode cp_ifile_inode;
};

#define NILFS_MIN_CHECKPOINT_SIZE       (64 + NILFS_MIN_INODE_SIZE)

/* checkpoint flags */
enum {
        NILFS_CHECKPOINT_SNAPSHOT,
        NILFS_CHECKPOINT_INVALID,
        NILFS_CHECKPOINT_SKETCH,
        NILFS_CHECKPOINT_MINOR,
};

#define NILFS_CHECKPOINT_FNS(flag, name)                                \
static inline void                                                      \
nilfs_checkpoint_set_##name(struct nilfs_checkpoint *cp)                \
{                                                                       \
        cp->cp_flags = __cpu_to_le32(__le32_to_cpu(cp->cp_flags) |      \
                                     (1UL << NILFS_CHECKPOINT_##flag)); \
}                                                                       \
static inline void                                                      \
nilfs_checkpoint_clear_##name(struct nilfs_checkpoint *cp)              \
{                                                                       \
        cp->cp_flags = __cpu_to_le32(__le32_to_cpu(cp->cp_flags) &      \
                                   ~(1UL << NILFS_CHECKPOINT_##flag));  \
}                                                                       \
static inline int                                                       \
nilfs_checkpoint_##name(const struct nilfs_checkpoint *cp)              \
{                                                                       \
        return !!(__le32_to_cpu(cp->cp_flags) &                         \
                  (1UL << NILFS_CHECKPOINT_##flag));                    \
}

NILFS_CHECKPOINT_FNS(SNAPSHOT, snapshot)
NILFS_CHECKPOINT_FNS(INVALID, invalid)
NILFS_CHECKPOINT_FNS(MINOR, minor)

/**
 * struct nilfs_cpfile_header - checkpoint file header
 * @ch_ncheckpoints: number of checkpoints
 * @ch_nsnapshots: number of snapshots
 * @ch_snapshot_list: snapshot list
 */
struct nilfs_cpfile_header {
        __le64 ch_ncheckpoints;
        __le64 ch_nsnapshots;
        struct nilfs_snapshot_list ch_snapshot_list;
};

#define NILFS_CPFILE_FIRST_CHECKPOINT_OFFSET                            \
        ((sizeof(struct nilfs_cpfile_header) +                          \
          sizeof(struct nilfs_checkpoint) - 1) /                        \
                        sizeof(struct nilfs_checkpoint))

/**
 * struct nilfs_segment_usage - segment usage
 * @su_lastmod: last modified timestamp
 * @su_nblocks: number of blocks in segment
 * @su_flags: flags
 */
struct nilfs_segment_usage {
        __le64 su_lastmod;
        __le32 su_nblocks;
        __le32 su_flags;
};

#define NILFS_MIN_SEGMENT_USAGE_SIZE    16

/* segment usage flag */
enum {
        NILFS_SEGMENT_USAGE_ACTIVE,
        NILFS_SEGMENT_USAGE_DIRTY,
        NILFS_SEGMENT_USAGE_ERROR,
};

#define NILFS_SEGMENT_USAGE_FNS(flag, name)                             \
static inline void                                                      \
nilfs_segment_usage_set_##name(struct nilfs_segment_usage *su)          \
{                                                                       \
        su->su_flags = __cpu_to_le32(__le32_to_cpu(su->su_flags) |      \
                                   (1UL << NILFS_SEGMENT_USAGE_##flag));\
}                                                                       \
static inline void                                                      \
nilfs_segment_usage_clear_##name(struct nilfs_segment_usage *su)        \
{                                                                       \
        su->su_flags =                                                  \
                __cpu_to_le32(__le32_to_cpu(su->su_flags) &             \
                            ~(1UL << NILFS_SEGMENT_USAGE_##flag));      \
}                                                                       \
static inline int                                                       \
nilfs_segment_usage_##name(const struct nilfs_segment_usage *su)        \
{                                                                       \
        return !!(__le32_to_cpu(su->su_flags) &                         \
                  (1UL << NILFS_SEGMENT_USAGE_##flag));                 \
}

NILFS_SEGMENT_USAGE_FNS(ACTIVE, active)
NILFS_SEGMENT_USAGE_FNS(DIRTY, dirty)
NILFS_SEGMENT_USAGE_FNS(ERROR, error)

static inline void
nilfs_segment_usage_set_clean(struct nilfs_segment_usage *su)
{
        su->su_lastmod = __cpu_to_le64(0);
        su->su_nblocks = __cpu_to_le32(0);
        su->su_flags = __cpu_to_le32(0);
}

static inline int
nilfs_segment_usage_clean(const struct nilfs_segment_usage *su)
{
        return !__le32_to_cpu(su->su_flags);
}

/**
 * struct nilfs_sufile_header - segment usage file header
 * @sh_ncleansegs: number of clean segments
 * @sh_ndirtysegs: number of dirty segments
 * @sh_last_alloc: last allocated segment number
 */
struct nilfs_sufile_header {
        __le64 sh_ncleansegs;
        __le64 sh_ndirtysegs;
        __le64 sh_last_alloc;
        /* ... */
};

#define NILFS_SUFILE_FIRST_SEGMENT_USAGE_OFFSET                         \
        ((sizeof(struct nilfs_sufile_header) +                          \
          sizeof(struct nilfs_segment_usage) - 1) /                     \
                         sizeof(struct nilfs_segment_usage))

#endif  /* _LINUX_NILFS2_ONDISK_H */