/*
   * 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 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.
   *
   * 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 Lesser General Public License for more details.

   *

   * You should have received a copy of the GNU Lesser 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>

  #include <linux/magic.h>

  #include <linux/bug.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;
  };
  
  /**
   * 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
   */
  struct nilfs_super_block {

  /*00*/	__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 */

  /*10*/	__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 */

  /*20*/	__le64  s_dev_size;		/* block device size in bytes */

  	__le64	s_first_data_block;	/* 1st seg disk block number */

  /*30*/	__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 */

  /*40*/	__le64  s_last_pseg;		/* disk block addr pseg written last */

  	__le64  s_last_seq;             /* seq. number of seg written last */

  /*50*/	__le64	s_free_blocks_count;	/* Free blocks count */

  
  	__le64	s_ctime;		/* Creation time (execution time of
  					   newfs) */

  /*60*/	__le64	s_mtime;		/* Mount time */

  	__le64	s_wtime;		/* Write time */

  /*70*/	__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 */

  /*80*/	__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 */

  /*90*/	__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 */

  /*98*/	__u8	s_uuid[16];		/* 128-bit uuid for volume */
  /*A8*/	char	s_volume_name[80];	/* volume name */

  /*F8*/	__le32  s_c_interval;           /* Commit interval of segment */

  	__le32  s_c_block_max;          /* Threshold of data amount for
  					   the segment construction */

  /*100*/	__le64  s_feature_compat;	/* Compatible feature set */
  	__le64  s_feature_compat_ro;	/* Read-only compatible feature set */
  	__le64  s_feature_incompat;	/* Incompatible feature set */
  	__u32	s_reserved[186];	/* 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 */

  #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)
  
  static inline unsigned nilfs_rec_len_from_disk(__le16 dlen)
  {
  	unsigned len = le16_to_cpu(dlen);

  #if !defined(__KERNEL__) || (PAGE_CACHE_SIZE >= 65536)

  	if (len == NILFS_MAX_REC_LEN)
  		return 1 << 16;

  #endif

  	return len;
  }
  
  static inline __le16 nilfs_rec_len_to_disk(unsigned len)
  {

  #if !defined(__KERNEL__) || (PAGE_CACHE_SIZE >= 65536)

  	if (len == (1 << 16))
  		return cpu_to_le16(NILFS_MAX_REC_LEN);
  	else if (len > (1 << 16))
  		BUG();

  #endif

  	return cpu_to_le16(len);
  }

  
  /**
   * 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 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 - B-tree node
   * @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
  
  /**

   * 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;
  };
  
  /**

   * 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;
  };
  
  /* 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_cpinfo - checkpoint information
   * @ci_flags: flags

   * @ci_pad: padding

   * @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;

  	__u32 ci_pad;

  	__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(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;
  };
  
  /* 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))
  
  /**
   * nilfs_suinfo - segment usage information

   * @sui_lastmod: timestamp of last modification
   * @sui_nblocks: number of written blocks in segment
   * @sui_flags: segment usage 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)

  
  static inline int nilfs_suinfo_clean(const struct nilfs_suinfo *si)
  {
  	return !si->sui_flags;
  }
  
  /* ioctl */
  enum {
  	NILFS_CHECKPOINT,
  	NILFS_SNAPSHOT,
  };
  
  /**

   * struct nilfs_cpmode - change checkpoint mode structure
   * @cm_cno: checkpoint number
   * @cm_mode: mode of checkpoint
   * @cm_pad: padding

   */
  struct nilfs_cpmode {
  	__u64 cm_cno;

  	__u32 cm_mode;
  	__u32 cm_pad;

  };
  
  /**
   * struct nilfs_argv - argument vector

   * @v_base: pointer on data array from userspace
   * @v_nmembs: number of members in data array
   * @v_size: size of data array in bytes
   * @v_flags: flags
   * @v_index: start number of target data items

   */
  struct nilfs_argv {

  	__u64 v_base;
  	__u32 v_nmembs;	/* number of members */
  	__u16 v_size;	/* size of members */
  	__u16 v_flags;
  	__u64 v_index;

  };
  
  /**

   * struct nilfs_period - period of checkpoint numbers
   * @p_start: start checkpoint number (inclusive)
   * @p_end: end checkpoint number (exclusive)

   */
  struct nilfs_period {
  	__u64 p_start;
  	__u64 p_end;
  };
  
  /**

   * struct nilfs_cpstat - checkpoint statistics

   * @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 - segment usage statistics

   * @ss_nsegs: number of segments
   * @ss_ncleansegs: number of clean segments
   * @ss_ndirtysegs: number of dirty segments

   * @ss_ctime: creation time of the last segment
   * @ss_nongc_ctime: creation time of the last segment not for GC
   * @ss_prot_seq: least sequence number of segments which must not be reclaimed

   */
  struct nilfs_sustat {
  	__u64 ss_nsegs;
  	__u64 ss_ncleansegs;
  	__u64 ss_ndirtysegs;

  	__u64 ss_ctime;
  	__u64 ss_nongc_ctime;

  	__u64 ss_prot_seq;

  };
  
  /**
   * struct nilfs_vinfo - virtual block number information

   * @vi_vblocknr: virtual block number
   * @vi_start: start checkpoint number (inclusive)
   * @vi_end: end checkpoint number (exclusive)
   * @vi_blocknr: disk block number

   */
  struct nilfs_vinfo {
  	__u64 vi_vblocknr;
  	__u64 vi_start;
  	__u64 vi_end;
  	__u64 vi_blocknr;
  };
  
  /**

   * struct nilfs_vdesc - descriptor of virtual block number
   * @vd_ino: inode number
   * @vd_cno: checkpoint number
   * @vd_vblocknr: virtual block number
   * @vd_period: period of checkpoint numbers
   * @vd_blocknr: disk block number
   * @vd_offset: logical block offset inside a file
   * @vd_flags: flags (data or node block)
   * @vd_pad: padding

   */
  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;

  	__u32 vd_pad;

  };
  
  /**

   * struct nilfs_bdesc - descriptor of disk block number
   * @bd_ino: inode number
   * @bd_oblocknr: disk block address (for skipping dead blocks)
   * @bd_blocknr: disk block address
   * @bd_offset: logical block offset inside a file
   * @bd_level: level in the b-tree organization
   * @bd_pad: padding

   */
  struct nilfs_bdesc {
  	__u64 bd_ino;
  	__u64 bd_oblocknr;
  	__u64 bd_blocknr;
  	__u64 bd_offset;
  	__u32 bd_level;

  	__u32 bd_pad;

  };

  #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_SYNC  \
  	_IOR(NILFS_IOCTL_IDENT, 0x8A, __u64)
  #define NILFS_IOCTL_RESIZE  \
  	_IOW(NILFS_IOCTL_IDENT, 0x8B, __u64)

  #define NILFS_IOCTL_SET_ALLOC_RANGE  \
  	_IOW(NILFS_IOCTL_IDENT, 0x8C, __u64[2])

  #endif	/* _LINUX_NILFS_FS_H */