nilfs2: move ioctl interface and disk layout to uapi separately
The header file "include/linux/nilfs2_fs.h" is composed of parts for
ioctl and disk format, and both are intended to be shared with user
space programs.
This moves them to the uapi directory "include/uapi/linux" splitting the
file to "nilfs2_api.h" and "nilfs2_ondisk.h". The following minor
changes are accompanied by this migration:
- nilfs_direct_node struct in nilfs2/direct.h is converged to
nilfs2_ondisk.h because it's an on-disk structure.
- inline functions nilfs_rec_len_from_disk() and
nilfs_rec_len_to_disk() are moved to nilfs2/dir.c.
Link: http://lkml.kernel.org/r/1465825507-3407-4-git-send-email-konishi.ryusuke@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>
diff --git a/include/uapi/linux/nilfs2_ondisk.h b/include/uapi/linux/nilfs2_ondisk.h
new file mode 100644
index 0000000..2a8a3ad
--- /dev/null
+++ b/include/uapi/linux/nilfs2_ondisk.h
@@ -0,0 +1,650 @@
+/*
+ * 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>
+
+
+#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 */