path: root/contrib/libs/linux-headers/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 
 */ 
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) 
 
/** 
 * 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 
 * @dn_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 */