nilfs2: disk format and userland interface

This adds a header file which specifies the on-disk format and ioctl
interface of the nilfs2 file system.

Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 854 insertions, 0 deletions

diff --git a/include/linux/nilfs2_fs.h b/include/linux/nilfs2_fs.h
new file mode 100644
index 000000000000..e38fad2f7c0b
--- /dev/null
+++ b/include/linux/nilfs2_fs.h
@@ -0,0 +1,854 @@
+/*
+ * nilfs2_fs.h - NILFS2 on-disk structures and common declarations.
+ *
+ * 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 General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Written by Koji Sato <koji@osrg.net>
+ *            Ryusuke Konishi <ryusuke@osrg.net>
+ */
+/*
+ *  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_NILFS_FS_H
+#define _LINUX_NILFS_FS_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+/*
+ * Inode flags stored in nilfs_inode and on-memory nilfs inode
+ *
+ * We define these flags based on ext2-fs because of the
+ * compatibility reason; to avoid problems in chattr(1)
+ */
+#define NILFS_SECRM_FL          0x00000001 /* Secure deletion */
+#define NILFS_UNRM_FL           0x00000002 /* Undelete */
+#define NILFS_SYNC_FL           0x00000008 /* Synchronous updates */
+#define NILFS_IMMUTABLE_FL      0x00000010 /* Immutable file */
+#define NILFS_APPEND_FL         0x00000020 /* writes to file may only append */
+#define NILFS_NODUMP_FL         0x00000040 /* do not dump file */
+#define NILFS_NOATIME_FL        0x00000080 /* do not update atime */
+/* Reserved for compression usage... */
+#define NILFS_NOTAIL_FL         0x00008000 /* file tail should not be merged */
+#define NILFS_DIRSYNC_FL        0x00010000 /* dirsync behaviour */
+
+#define NILFS_FL_USER_VISIBLE   0x0003DFFF /* User visible flags */
+#define NILFS_FL_USER_MODIFIABLE        0x000380FF /* User modifiable flags */
+
+
+#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
+ * @i_mtime: modification time
+ * @i_dtime: deletion time
+ * @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;
+        __le64  i_dtime;
+        __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;
+};
+
+/**
+ * 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                  (sizeof(struct nilfs_super_root))
+
+/*
+ * 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_SNAPSHOT            0x0080  /* Snapshot flag */
+#define NILFS_MOUNT_BARRIER             0x1000  /* Use block barriers */
+#define NILFS_MOUNT_STRICT_ORDER        0x2000  /* Apply strict in-order
+                                                   semantics also for data */
+
+
+/**
+ * struct nilfs_super_block - structure of super block on disk
+ */
+struct nilfs_super_block {
+        __le32  s_rev_level;            /* Revision level */
+        __le16  s_minor_rev_level;      /* minor revision level */
+        __le16  s_magic;                /* Magic signature */
+
+        __le16  s_bytes;                /* Bytes count of CRC calculation
+                                           for this structure. s_reserved
+                                           is excluded. */
+        __le16  s_flags;                /* flags */
+        __le32  s_crc_seed;             /* Seed value of CRC calculation */
+        __le32  s_sum;                  /* Check sum of super block */
+
+        __le32  s_log_block_size;       /* Block size represented as follows
+                                           blocksize =
+                                               1 << (s_log_block_size + 10) */
+        __le64  s_nsegments;            /* Number of segments in filesystem */
+        __le64  s_dev_size;             /* block device size in bytes */
+        __le64  s_first_data_block;     /* 1st seg disk block number */
+        __le32  s_blocks_per_segment;   /* number of blocks per full segment */
+        __le32  s_r_segments_percentage; /* Reserved segments percentage */
+
+        __le64  s_last_cno;             /* Last checkpoint number */
+        __le64  s_last_pseg;            /* disk block addr pseg written last */
+        __le64  s_last_seq;             /* seq. number of seg written last */
+        __le64  s_free_blocks_count;    /* Free blocks count */
+
+        __le64  s_ctime;                /* Creation time (execution time of
+                                           newfs) */
+        __le64  s_mtime;                /* Mount time */
+        __le64  s_wtime;                /* Write time */
+        __le16  s_mnt_count;            /* Mount count */
+        __le16  s_max_mnt_count;        /* Maximal mount count */
+        __le16  s_state;                /* File system state */
+        __le16  s_errors;               /* Behaviour when detecting errors */
+        __le64  s_lastcheck;            /* time of last check */
+
+        __le32  s_checkinterval;        /* max. time between checks */
+        __le32  s_creator_os;           /* OS */
+        __le16  s_def_resuid;           /* Default uid for reserved blocks */
+        __le16  s_def_resgid;           /* Default gid for reserved blocks */
+        __le32  s_first_ino;            /* First non-reserved inode */
+
+        __le16  s_inode_size;           /* Size of an inode */
+        __le16  s_dat_entry_size;       /* Size of a dat entry */
+        __le16  s_checkpoint_size;      /* Size of a checkpoint */
+        __le16  s_segment_usage_size;   /* Size of a segment usage */
+
+        __u8    s_uuid[16];             /* 128-bit uuid for volume */
+        char    s_volume_name[16];      /* volume name */
+        char    s_last_mounted[64];     /* directory where last mounted */
+
+        __le32  s_c_interval;           /* Commit interval of segment */
+        __le32  s_c_block_max;          /* Threshold of data amount for
+                                           the segment construction */
+        __u32   s_reserved[192];        /* padding to the end of the block */
+};
+
+/*
+ * 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 */
+
+/*
+ * 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_SUPER_MAGIC       0x3434  /* NILFS filesystem  magic number */
+
+#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 */
+
+
+/*
+ * 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
+
+/*
+ * 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;
+        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)
+
+
+/**
+ * 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;
+        /* array of virtual block numbers */
+};
+
+/**
+ * struct nilfs_binfo_v - information for the block to which a virtual block number is assigned
+ * @bi_vblocknr: virtual block number
+ * @bi_blkoff: block offset
+ */
+struct nilfs_binfo_v {
+        __le64 bi_vblocknr;
+        __le64 bi_blkoff;
+};
+
+/**
+ * struct nilfs_binfo_dat - information for the block which belongs to the DAT file
+ * @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
+ * @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
+ */
+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;
+        /* 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_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
+ * @dt_blocknr: block number
+ * @dt_start: start checkpoint number
+ * @dt_end: end checkpoint number
+ * @dt_rsv: reserved for future use
+ */
+struct nilfs_dat_entry {
+        __le64 de_blocknr;
+        __le64 de_start;
+        __le64 de_end;
+        __le64 de_rsv;
+};
+
+/**
+ * struct nilfs_dat_group_desc - block group descriptor
+ * @dg_nfrees: number of free virtual block numbers in block group
+ */
+struct nilfs_dat_group_desc {
+        __le32 dg_nfrees;
+};
+
+
+/**
+ * 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;         /* Reserved (might be deleted) */
+
+        /* 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;
+};
+
+/* checkpoint flags */
+enum {
+        NILFS_CHECKPOINT_SNAPSHOT,
+        NILFS_CHECKPOINT_INVALID,
+        NILFS_CHECKPOINT_SKETCH,
+};
+
+#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(SKETCH, sketch)
+
+/**
+ * struct nilfs_cpinfo - checkpoint information
+ * @ci_flags: flags
+ * @ci_cno: checkpoint number
+ * @ci_create: creation timestamp
+ * @ci_nblk_inc: number of blocks incremented by this checkpoint
+ * @ci_inodes_count: inodes count
+ * @ci_blocks_count: blocks count
+ * @ci_next: next checkpoint number in snapshot list
+ */
+struct nilfs_cpinfo {
+        __u32 ci_flags;
+        __u64 ci_cno;
+        __u64 ci_create;
+        __u64 ci_nblk_inc;
+        __u64 ci_inodes_count;
+        __u64 ci_blocks_count;
+        __u64 ci_next;
+};
+
+#define NILFS_CPINFO_FNS(flag, name)                                    \
+static inline int                                                       \
+nilfs_cpinfo_##name(const struct nilfs_cpinfo *cpinfo)                  \
+{                                                                       \
+        return !!(cpinfo->ci_flags & (1UL << NILFS_CHECKPOINT_##flag)); \
+}
+
+NILFS_CPINFO_FNS(SNAPSHOT, snapshot)
+NILFS_CPINFO_FNS(INVALID, invalid)
+NILFS_CPINFO_FNS(SKETCH, sketch)
+
+
+/**
+ * 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;
+};
+
+/* segment usage flag */
+enum {
+        NILFS_SEGMENT_USAGE_ACTIVE,
+        NILFS_SEGMENT_USAGE_DIRTY,
+        NILFS_SEGMENT_USAGE_ERROR,
+
+        /* on-memory only */
+        NILFS_SEGMENT_USAGE_VOLATILE_ACTIVE,
+        /* ... */
+};
+
+#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)
+NILFS_SEGMENT_USAGE_FNS(VOLATILE_ACTIVE, volatile_active)
+
+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))
+
+/**
+ * nilfs_suinfo - segment usage information
+ * @sui_lastmod:
+ * @sui_nblocks:
+ * @sui_flags:
+ */
+struct nilfs_suinfo {
+        __u64 sui_lastmod;
+        __u32 sui_nblocks;
+        __u32 sui_flags;
+};
+
+#define NILFS_SUINFO_FNS(flag, name)                                    \
+static inline int                                                       \
+nilfs_suinfo_##name(const struct nilfs_suinfo *si)                      \
+{                                                                       \
+        return si->sui_flags & (1UL << NILFS_SEGMENT_USAGE_##flag);     \
+}
+
+NILFS_SUINFO_FNS(ACTIVE, active)
+NILFS_SUINFO_FNS(DIRTY, dirty)
+NILFS_SUINFO_FNS(ERROR, error)
+NILFS_SUINFO_FNS(VOLATILE_ACTIVE, volatile_active)
+
+static inline int nilfs_suinfo_clean(const struct nilfs_suinfo *si)
+{
+        return !si->sui_flags;
+}
+
+/* ioctl */
+enum {
+        NILFS_CHECKPOINT,
+        NILFS_SNAPSHOT,
+};
+
+/**
+ * struct nilfs_cpmode -
+ * @cc_cno:
+ * @cc_mode:
+ */
+struct nilfs_cpmode {
+        __u64 cm_cno;
+        int cm_mode;
+};
+
+/**
+ * struct nilfs_argv - argument vector
+ * @v_base:
+ * @v_nmembs:
+ * @v_size:
+ * @v_index:
+ * @v_flags:
+ */
+struct nilfs_argv {
+        void *v_base;
+        size_t v_nmembs;        /* number of members */
+        size_t v_size;          /* size of members */
+        int v_index;
+        int v_flags;
+};
+
+/**
+ * struct nilfs_period -
+ * @p_start:
+ * @p_end:
+ */
+struct nilfs_period {
+        __u64 p_start;
+        __u64 p_end;
+};
+
+/**
+ * struct nilfs_cpstat -
+ * @cs_cno: checkpoint number
+ * @cs_ncps: number of checkpoints
+ * @cs_nsss: number of snapshots
+ */
+struct nilfs_cpstat {
+        __u64 cs_cno;
+        __u64 cs_ncps;
+        __u64 cs_nsss;
+};
+
+/**
+ * struct nilfs_sustat -
+ * @ss_nsegs: number of segments
+ * @ss_ncleansegs: number of clean segments
+ * @ss_ndirtysegs: number of dirty segments
+ * @ss_ctime:
+ * @ss_nongc_ctime:
+ */
+struct nilfs_sustat {
+        __u64 ss_nsegs;
+        __u64 ss_ncleansegs;
+        __u64 ss_ndirtysegs;
+        time_t ss_ctime;
+        time_t ss_nongc_ctime;
+};
+
+/**
+ * struct nilfs_vinfo - virtual block number information
+ * @vi_vblocknr:
+ * @vi_start:
+ * @vi_end:
+ * @vi_blocknr:
+ */
+struct nilfs_vinfo {
+        __u64 vi_vblocknr;
+        __u64 vi_start;
+        __u64 vi_end;
+        __u64 vi_blocknr;
+};
+
+/**
+ * struct nilfs_vdesc -
+ */
+struct nilfs_vdesc {
+        __u64 vd_ino;
+        __u64 vd_cno;
+        __u64 vd_vblocknr;
+        struct nilfs_period vd_period;
+        __u64 vd_blocknr;
+        __u64 vd_offset;
+        __u32 vd_flags;
+};
+
+/**
+ * struct nilfs_bdesc -
+ */
+struct nilfs_bdesc {
+        __u64 bd_ino;
+        __u64 bd_oblocknr;
+        __u64 bd_blocknr;
+        __u64 bd_offset;
+        __u32 bd_level;
+};
+
+#define NILFS_TIMEDWAIT_WRITE_LOCKED    0x1
+#define NILFS_TIMEDWAIT_SEG_WRITE       0x2
+
+/**
+ * struct nilfs_wait_cond -
+ */
+struct nilfs_wait_cond {
+        int wc_cond;
+        int wc_flags;
+        struct timespec wc_timeout;
+};
+
+#define NILFS_IOCTL_IDENT               'n'
+
+#define NILFS_IOCTL_CHANGE_CPMODE  \
+        _IOW(NILFS_IOCTL_IDENT, 0x80, struct nilfs_cpmode)
+#define NILFS_IOCTL_DELETE_CHECKPOINT  \
+        _IOW(NILFS_IOCTL_IDENT, 0x81, __u64)
+#define NILFS_IOCTL_GET_CPINFO  \
+        _IOR(NILFS_IOCTL_IDENT, 0x82, struct nilfs_argv)
+#define NILFS_IOCTL_GET_CPSTAT  \
+        _IOR(NILFS_IOCTL_IDENT, 0x83, struct nilfs_cpstat)
+#define NILFS_IOCTL_GET_SUINFO  \
+        _IOR(NILFS_IOCTL_IDENT, 0x84, struct nilfs_argv)
+#define NILFS_IOCTL_GET_SUSTAT  \
+        _IOR(NILFS_IOCTL_IDENT, 0x85, struct nilfs_sustat)
+#define NILFS_IOCTL_GET_VINFO  \
+        _IOWR(NILFS_IOCTL_IDENT, 0x86, struct nilfs_argv)
+#define NILFS_IOCTL_GET_BDESCS  \
+        _IOWR(NILFS_IOCTL_IDENT, 0x87, struct nilfs_argv)
+#define NILFS_IOCTL_CLEAN_SEGMENTS  \
+        _IOW(NILFS_IOCTL_IDENT, 0x88, struct nilfs_argv[5])
+#define NILFS_IOCTL_TIMEDWAIT  \
+        _IOWR(NILFS_IOCTL_IDENT, 0x89, struct nilfs_wait_cond)
+#define NILFS_IOCTL_SYNC  \
+        _IOR(NILFS_IOCTL_IDENT, 0x8A, __u64)
+#define NILFS_IOCTL_RESIZE  \
+        _IOW(NILFS_IOCTL_IDENT, 0x8B, __u64)
+
+/* compat_ioctl */
+#ifdef CONFIG_COMPAT
+#include <linux/compat.h>
+
+struct nilfs_cpmode32 {
+        __u64 cm_cno;
+        compat_int_t cm_mode;
+};
+
+struct nilfs_argv32 {
+        compat_caddr_t v_base;
+        compat_size_t v_nmembs;
+        compat_size_t v_size;
+        compat_int_t v_index;
+        compat_int_t v_flags;
+};
+
+struct nilfs_sustat32 {
+        __u64 ss_nsegs;
+        __u64 ss_ncleansegs;
+        __u64 ss_ndirtysegs;
+        compat_time_t ss_ctime;
+        compat_time_t ss_nongc_ctime;
+};
+
+struct nilfs_wait_cond32 {
+        compat_int_t wc_cond;
+        compat_int_t wc_flags;
+        struct compat_timespec wc_timeout;
+};
+
+#define NILFS_IOCTL32_CHANGE_CPMODE  \
+        _IOW(NILFS_IOCTL_IDENT, 0x80, struct nilfs_cpmode32)
+#define NILFS_IOCTL32_GET_CPINFO  \
+        _IOR(NILFS_IOCTL_IDENT, 0x82, struct nilfs_argv32)
+#define NILFS_IOCTL32_GET_SUINFO  \
+        _IOR(NILFS_IOCTL_IDENT, 0x84, struct nilfs_argv32)
+#define NILFS_IOCTL32_GET_SUSTAT  \
+        _IOR(NILFS_IOCTL_IDENT, 0x85, struct nilfs_sustat32)
+#define NILFS_IOCTL32_GET_VINFO  \
+        _IOWR(NILFS_IOCTL_IDENT, 0x86, struct nilfs_argv32)
+#define NILFS_IOCTL32_GET_BDESCS  \
+        _IOWR(NILFS_IOCTL_IDENT, 0x87, struct nilfs_argv32)
+#define NILFS_IOCTL32_CLEAN_SEGMENTS  \
+        _IOW(NILFS_IOCTL_IDENT, 0x88, struct nilfs_argv32[5])
+#define NILFS_IOCTL32_TIMEDWAIT  \
+        _IOWR(NILFS_IOCTL_IDENT, 0x89, struct nilfs_wait_cond32)
+#endif  /* CONFIG_COMPAT */
+
+#endif  /* _LINUX_NILFS_FS_H */