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 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
  * All Rights Reserved.
  */
 #ifndef __XFS_FORMAT_H__
 #define __XFS_FORMAT_H__
 
 /*
  * XFS On Disk Format Definitions
  *
  * This header file defines all the on-disk format definitions for
  * general XFS objects. Directory and attribute related objects are defined in
  * xfs_da_format.h, which log and log item formats are defined in
  * xfs_log_format.h. Everything else goes here.
  */
 
 struct xfs_mount;
 struct xfs_trans;
 struct xfs_inode;
 struct xfs_buf;
 struct xfs_ifork;
 
 /*
  * Super block
  * Fits into a sector-sized buffer at address 0 of each allocation group.
  * Only the first of these is ever updated except during growfs.
  */
 #define XFS_SB_MAGIC        0x58465342  /* 'XFSB' */
 #define XFS_SB_VERSION_1    1       /* 5.3, 6.0.1, 6.1 */
 #define XFS_SB_VERSION_2    2       /* 6.2 - attributes */
 #define XFS_SB_VERSION_3    3       /* 6.2 - new inode version */
 #define XFS_SB_VERSION_4    4       /* 6.2+ - bitmask version */
 #define XFS_SB_VERSION_5    5       /* CRC enabled filesystem */
 #define XFS_SB_VERSION_NUMBITS      0x000f
 #define XFS_SB_VERSION_ALLFBITS     0xfff0
 #define XFS_SB_VERSION_ATTRBIT      0x0010
 #define XFS_SB_VERSION_NLINKBIT     0x0020
 #define XFS_SB_VERSION_QUOTABIT     0x0040
 #define XFS_SB_VERSION_ALIGNBIT     0x0080
 #define XFS_SB_VERSION_DALIGNBIT    0x0100
 #define XFS_SB_VERSION_SHAREDBIT    0x0200
 #define XFS_SB_VERSION_LOGV2BIT     0x0400
 #define XFS_SB_VERSION_SECTORBIT    0x0800
 #define XFS_SB_VERSION_EXTFLGBIT    0x1000
 #define XFS_SB_VERSION_DIRV2BIT     0x2000
 #define XFS_SB_VERSION_BORGBIT      0x4000  /* ASCII only case-insens. */
 #define XFS_SB_VERSION_MOREBITSBIT  0x8000
 
 /*
  * The size of a single extended attribute on disk is limited by
  * the size of index values within the attribute entries themselves.
  * These are be16 fields, so we can only support attribute data
  * sizes up to 2^16 bytes in length.
  */
 #define XFS_XATTR_SIZE_MAX (1 << 16)
 
 /*
  * Supported feature bit list is just all bits in the versionnum field because
  * we've used them all up and understand them all. Except, of course, for the
  * shared superblock bit, which nobody knows what it does and so is unsupported.
  */
 #define XFS_SB_VERSION_OKBITS       \
     ((XFS_SB_VERSION_NUMBITS | XFS_SB_VERSION_ALLFBITS) & \
         ~XFS_SB_VERSION_SHAREDBIT)
 
 /*
  * There are two words to hold XFS "feature" bits: the original
  * word, sb_versionnum, and sb_features2.  Whenever a bit is set in
  * sb_features2, the feature bit XFS_SB_VERSION_MOREBITSBIT must be set.
  *
  * These defines represent bits in sb_features2.
  */
 #define XFS_SB_VERSION2_RESERVED1BIT    0x00000001
 #define XFS_SB_VERSION2_LAZYSBCOUNTBIT  0x00000002  /* Superblk counters */
 #define XFS_SB_VERSION2_RESERVED4BIT    0x00000004
 #define XFS_SB_VERSION2_ATTR2BIT    0x00000008  /* Inline attr rework */
 #define XFS_SB_VERSION2_PARENTBIT   0x00000010  /* parent pointers */
 #define XFS_SB_VERSION2_PROJID32BIT 0x00000080  /* 32 bit project id */
 #define XFS_SB_VERSION2_CRCBIT      0x00000100  /* metadata CRCs */
 #define XFS_SB_VERSION2_FTYPE       0x00000200  /* inode type in dir */
 
 #define XFS_SB_VERSION2_OKBITS      \
     (XFS_SB_VERSION2_LAZYSBCOUNTBIT | \
      XFS_SB_VERSION2_ATTR2BIT   | \
      XFS_SB_VERSION2_PROJID32BIT    | \
      XFS_SB_VERSION2_FTYPE)
 
 /* Maximum size of the xfs filesystem label, no terminating NULL */
 #define XFSLABEL_MAX            12
 
 /*
  * Superblock - in core version.  Must match the ondisk version below.
  * Must be padded to 64 bit alignment.
  */
 typedef struct xfs_sb {
     uint32_t    sb_magicnum;    /* magic number == XFS_SB_MAGIC */
     uint32_t    sb_blocksize;   /* logical block size, bytes */
     xfs_rfsblock_t  sb_dblocks; /* number of data blocks */
     xfs_rfsblock_t  sb_rblocks; /* number of realtime blocks */
     xfs_rtblock_t   sb_rextents;    /* number of realtime extents */
     uuid_t      sb_uuid;    /* user-visible file system unique id */
     xfs_fsblock_t   sb_logstart;    /* starting block of log if internal */
     xfs_ino_t   sb_rootino; /* root inode number */
     xfs_ino_t   sb_rbmino;  /* bitmap inode for realtime extents */
     xfs_ino_t   sb_rsumino; /* summary inode for rt bitmap */
     xfs_agblock_t   sb_rextsize;    /* realtime extent size, blocks */
     xfs_agblock_t   sb_agblocks;    /* size of an allocation group */
     xfs_agnumber_t  sb_agcount; /* number of allocation groups */
     xfs_extlen_t    sb_rbmblocks;   /* number of rt bitmap blocks */
     xfs_extlen_t    sb_logblocks;   /* number of log blocks */
     uint16_t    sb_versionnum;  /* header version == XFS_SB_VERSION */
     uint16_t    sb_sectsize;    /* volume sector size, bytes */
     uint16_t    sb_inodesize;   /* inode size, bytes */
     uint16_t    sb_inopblock;   /* inodes per block */
     char        sb_fname[XFSLABEL_MAX]; /* file system name */
     uint8_t     sb_blocklog;    /* log2 of sb_blocksize */
     uint8_t     sb_sectlog; /* log2 of sb_sectsize */
     uint8_t     sb_inodelog;    /* log2 of sb_inodesize */
     uint8_t     sb_inopblog;    /* log2 of sb_inopblock */
     uint8_t     sb_agblklog;    /* log2 of sb_agblocks (rounded up) */
     uint8_t     sb_rextslog;    /* log2 of sb_rextents */
     uint8_t     sb_inprogress;  /* mkfs is in progress, don't mount */
     uint8_t     sb_imax_pct;    /* max % of fs for inode space */
                     /* statistics */
     /*
      * These fields must remain contiguous.  If you really
      * want to change their layout, make sure you fix the
      * code in xfs_trans_apply_sb_deltas().
      */
     uint64_t    sb_icount;  /* allocated inodes */
     uint64_t    sb_ifree;   /* free inodes */
     uint64_t    sb_fdblocks;    /* free data blocks */
     uint64_t    sb_frextents;   /* free realtime extents */
     /*
      * End contiguous fields.
      */
     xfs_ino_t   sb_uquotino;    /* user quota inode */
     xfs_ino_t   sb_gquotino;    /* group quota inode */
     uint16_t    sb_qflags;  /* quota flags */
     uint8_t     sb_flags;   /* misc. flags */
     uint8_t     sb_shared_vn;   /* shared version number */
     xfs_extlen_t    sb_inoalignmt;  /* inode chunk alignment, fsblocks */
     uint32_t    sb_unit;    /* stripe or raid unit */
     uint32_t    sb_width;   /* stripe or raid width */
     uint8_t     sb_dirblklog;   /* log2 of dir block size (fsbs) */
     uint8_t     sb_logsectlog;  /* log2 of the log sector size */
     uint16_t    sb_logsectsize; /* sector size for the log, bytes */
     uint32_t    sb_logsunit;    /* stripe unit size for the log */
     uint32_t    sb_features2;   /* additional feature bits */
 
     /*
      * bad features2 field as a result of failing to pad the sb structure to
      * 64 bits. Some machines will be using this field for features2 bits.
      * Easiest just to mark it bad and not use it for anything else.
      *
      * This is not kept up to date in memory; it is always overwritten by
      * the value in sb_features2 when formatting the incore superblock to
      * the disk buffer.
      */
     uint32_t    sb_bad_features2;
 
     /* version 5 superblock fields start here */
 
     /* feature masks */
     uint32_t    sb_features_compat;
     uint32_t    sb_features_ro_compat;
     uint32_t    sb_features_incompat;
     uint32_t    sb_features_log_incompat;
 
     uint32_t    sb_crc;     /* superblock crc */
     xfs_extlen_t    sb_spino_align; /* sparse inode chunk alignment */
 
     xfs_ino_t   sb_pquotino;    /* project quota inode */
     xfs_lsn_t   sb_lsn;     /* last write sequence */
     uuid_t      sb_meta_uuid;   /* metadata file system unique id */
 
     /* must be padded to 64 bit alignment */
 } xfs_sb_t;
 
 #define XFS_SB_CRC_OFF      offsetof(struct xfs_sb, sb_crc)
 
 /*
  * Superblock - on disk version.  Must match the in core version above.
  * Must be padded to 64 bit alignment.
  */
 struct xfs_dsb {
     __be32      sb_magicnum;    /* magic number == XFS_SB_MAGIC */
     __be32      sb_blocksize;   /* logical block size, bytes */
     __be64      sb_dblocks; /* number of data blocks */
     __be64      sb_rblocks; /* number of realtime blocks */
     __be64      sb_rextents;    /* number of realtime extents */
     uuid_t      sb_uuid;    /* user-visible file system unique id */
     __be64      sb_logstart;    /* starting block of log if internal */
     __be64      sb_rootino; /* root inode number */
     __be64      sb_rbmino;  /* bitmap inode for realtime extents */
     __be64      sb_rsumino; /* summary inode for rt bitmap */
     __be32      sb_rextsize;    /* realtime extent size, blocks */
     __be32      sb_agblocks;    /* size of an allocation group */
     __be32      sb_agcount; /* number of allocation groups */
     __be32      sb_rbmblocks;   /* number of rt bitmap blocks */
     __be32      sb_logblocks;   /* number of log blocks */
     __be16      sb_versionnum;  /* header version == XFS_SB_VERSION */
     __be16      sb_sectsize;    /* volume sector size, bytes */
     __be16      sb_inodesize;   /* inode size, bytes */
     __be16      sb_inopblock;   /* inodes per block */
     char        sb_fname[XFSLABEL_MAX]; /* file system name */
     __u8        sb_blocklog;    /* log2 of sb_blocksize */
     __u8        sb_sectlog; /* log2 of sb_sectsize */
     __u8        sb_inodelog;    /* log2 of sb_inodesize */
     __u8        sb_inopblog;    /* log2 of sb_inopblock */
     __u8        sb_agblklog;    /* log2 of sb_agblocks (rounded up) */
     __u8        sb_rextslog;    /* log2 of sb_rextents */
     __u8        sb_inprogress;  /* mkfs is in progress, don't mount */
     __u8        sb_imax_pct;    /* max % of fs for inode space */
                     /* statistics */
     /*
      * These fields must remain contiguous.  If you really
      * want to change their layout, make sure you fix the
      * code in xfs_trans_apply_sb_deltas().
      */
     __be64      sb_icount;  /* allocated inodes */
     __be64      sb_ifree;   /* free inodes */
     __be64      sb_fdblocks;    /* free data blocks */
     __be64      sb_frextents;   /* free realtime extents */
     /*
      * End contiguous fields.
      */
     __be64      sb_uquotino;    /* user quota inode */
     __be64      sb_gquotino;    /* group quota inode */
     __be16      sb_qflags;  /* quota flags */
     __u8        sb_flags;   /* misc. flags */
     __u8        sb_shared_vn;   /* shared version number */
     __be32      sb_inoalignmt;  /* inode chunk alignment, fsblocks */
     __be32      sb_unit;    /* stripe or raid unit */
     __be32      sb_width;   /* stripe or raid width */
     __u8        sb_dirblklog;   /* log2 of dir block size (fsbs) */
     __u8        sb_logsectlog;  /* log2 of the log sector size */
     __be16      sb_logsectsize; /* sector size for the log, bytes */
     __be32      sb_logsunit;    /* stripe unit size for the log */
     __be32      sb_features2;   /* additional feature bits */
     /*
      * bad features2 field as a result of failing to pad the sb
      * structure to 64 bits. Some machines will be using this field
      * for features2 bits. Easiest just to mark it bad and not use
      * it for anything else.
      */
     __be32      sb_bad_features2;
 
     /* version 5 superblock fields start here */
 
     /* feature masks */
     __be32      sb_features_compat;
     __be32      sb_features_ro_compat;
     __be32      sb_features_incompat;
     __be32      sb_features_log_incompat;
 
     __le32      sb_crc;     /* superblock crc */
     __be32      sb_spino_align; /* sparse inode chunk alignment */
 
     __be64      sb_pquotino;    /* project quota inode */
     __be64      sb_lsn;     /* last write sequence */
     uuid_t      sb_meta_uuid;   /* metadata file system unique id */
 
     /* must be padded to 64 bit alignment */
 };
 
 /*
  * Misc. Flags - warning - these will be cleared by xfs_repair unless
  * a feature bit is set when the flag is used.
  */
 #define XFS_SBF_NOFLAGS     0x00    /* no flags set */
 #define XFS_SBF_READONLY    0x01    /* only read-only mounts allowed */
 
 /*
  * define max. shared version we can interoperate with
  */
 #define XFS_SB_MAX_SHARED_VN    0
 
 #define XFS_SB_VERSION_NUM(sbp) ((sbp)->sb_versionnum & XFS_SB_VERSION_NUMBITS)
 
 static inline bool xfs_sb_is_v5(struct xfs_sb *sbp)
 {
     return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5;
 }
 
 /*
  * Detect a mismatched features2 field.  Older kernels read/wrote
  * this into the wrong slot, so to be safe we keep them in sync.
  */
 static inline bool xfs_sb_has_mismatched_features2(struct xfs_sb *sbp)
 {
     return sbp->sb_bad_features2 != sbp->sb_features2;
 }
 
 static inline bool xfs_sb_version_hasmorebits(struct xfs_sb *sbp)
 {
     return xfs_sb_is_v5(sbp) ||
            (sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT);
 }
 
 static inline void xfs_sb_version_addattr(struct xfs_sb *sbp)
 {
     sbp->sb_versionnum |= XFS_SB_VERSION_ATTRBIT;
 }
 
 static inline void xfs_sb_version_addquota(struct xfs_sb *sbp)
 {
     sbp->sb_versionnum |= XFS_SB_VERSION_QUOTABIT;
 }
 
 static inline void xfs_sb_version_addattr2(struct xfs_sb *sbp)
 {
     sbp->sb_versionnum |= XFS_SB_VERSION_MOREBITSBIT;
     sbp->sb_features2 |= XFS_SB_VERSION2_ATTR2BIT;
 }
 
 static inline void xfs_sb_version_addprojid32(struct xfs_sb *sbp)
 {
     sbp->sb_versionnum |= XFS_SB_VERSION_MOREBITSBIT;
     sbp->sb_features2 |= XFS_SB_VERSION2_PROJID32BIT;
 }
 
 /*
  * Extended v5 superblock feature masks. These are to be used for new v5
  * superblock features only.
  *
  * Compat features are new features that old kernels will not notice or affect
  * and so can mount read-write without issues.
  *
  * RO-Compat (read only) are features that old kernels can read but will break
  * if they write. Hence only read-only mounts of such filesystems are allowed on
  * kernels that don't support the feature bit.
  *
  * InCompat features are features which old kernels will not understand and so
  * must not mount.
  *
  * Log-InCompat features are for changes to log formats or new transactions that
  * can't be replayed on older kernels. The fields are set when the filesystem is
  * mounted, and a clean unmount clears the fields.
  */
 #define XFS_SB_FEAT_COMPAT_ALL 0
 #define XFS_SB_FEAT_COMPAT_UNKNOWN  ~XFS_SB_FEAT_COMPAT_ALL
 static inline bool
 xfs_sb_has_compat_feature(
     struct xfs_sb   *sbp,
     uint32_t    feature)
 {
     return (sbp->sb_features_compat & feature) != 0;
 }
 
 #define XFS_SB_FEAT_RO_COMPAT_FINOBT   (1 << 0)     /* free inode btree */
 #define XFS_SB_FEAT_RO_COMPAT_RMAPBT   (1 << 1)     /* reverse map btree */
 #define XFS_SB_FEAT_RO_COMPAT_REFLINK  (1 << 2)     /* reflinked files */
 #define XFS_SB_FEAT_RO_COMPAT_INOBTCNT (1 << 3)     /* inobt block counts */
 #define XFS_SB_FEAT_RO_COMPAT_ALL \
         (XFS_SB_FEAT_RO_COMPAT_FINOBT | \
          XFS_SB_FEAT_RO_COMPAT_RMAPBT | \
          XFS_SB_FEAT_RO_COMPAT_REFLINK| \
          XFS_SB_FEAT_RO_COMPAT_INOBTCNT)
 #define XFS_SB_FEAT_RO_COMPAT_UNKNOWN   ~XFS_SB_FEAT_RO_COMPAT_ALL
 static inline bool
 xfs_sb_has_ro_compat_feature(
     struct xfs_sb   *sbp,
     uint32_t    feature)
 {
     return (sbp->sb_features_ro_compat & feature) != 0;
 }
 
 #define XFS_SB_FEAT_INCOMPAT_FTYPE  (1 << 0)    /* filetype in dirent */
 #define XFS_SB_FEAT_INCOMPAT_SPINODES   (1 << 1)    /* sparse inode chunks */
 #define XFS_SB_FEAT_INCOMPAT_META_UUID  (1 << 2)    /* metadata UUID */
 #define XFS_SB_FEAT_INCOMPAT_BIGTIME    (1 << 3)    /* large timestamps */
 #define XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR (1 << 4)   /* needs xfs_repair */
 #define XFS_SB_FEAT_INCOMPAT_NREXT64    (1 << 5)    /* large extent counters */
 #define XFS_SB_FEAT_INCOMPAT_ALL \
         (XFS_SB_FEAT_INCOMPAT_FTYPE|    \
          XFS_SB_FEAT_INCOMPAT_SPINODES| \
          XFS_SB_FEAT_INCOMPAT_META_UUID| \
          XFS_SB_FEAT_INCOMPAT_BIGTIME| \
          XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR| \
          XFS_SB_FEAT_INCOMPAT_NREXT64)
 
 #define XFS_SB_FEAT_INCOMPAT_UNKNOWN    ~XFS_SB_FEAT_INCOMPAT_ALL
 static inline bool
 xfs_sb_has_incompat_feature(
     struct xfs_sb   *sbp,
     uint32_t    feature)
 {
     return (sbp->sb_features_incompat & feature) != 0;
 }
 
 #define XFS_SB_FEAT_INCOMPAT_LOG_XATTRS   (1 << 0)  /* Delayed Attributes */
 #define XFS_SB_FEAT_INCOMPAT_LOG_ALL \
     (XFS_SB_FEAT_INCOMPAT_LOG_XATTRS)
 #define XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN    ~XFS_SB_FEAT_INCOMPAT_LOG_ALL
 static inline bool
 xfs_sb_has_incompat_log_feature(
     struct xfs_sb   *sbp,
     uint32_t    feature)
 {
     return (sbp->sb_features_log_incompat & feature) != 0;
 }
 
 static inline void
 xfs_sb_remove_incompat_log_features(
     struct xfs_sb   *sbp)
 {
     sbp->sb_features_log_incompat &= ~XFS_SB_FEAT_INCOMPAT_LOG_ALL;
 }
 
 static inline void
 xfs_sb_add_incompat_log_features(
     struct xfs_sb   *sbp,
     unsigned int    features)
 {
     sbp->sb_features_log_incompat |= features;
 }
 
 static inline bool xfs_sb_version_haslogxattrs(struct xfs_sb *sbp)
 {
     return xfs_sb_is_v5(sbp) && (sbp->sb_features_log_incompat &
          XFS_SB_FEAT_INCOMPAT_LOG_XATTRS);
 }
 
 static inline bool
 xfs_is_quota_inode(struct xfs_sb *sbp, xfs_ino_t ino)
 {
     return (ino == sbp->sb_uquotino ||
         ino == sbp->sb_gquotino ||
         ino == sbp->sb_pquotino);
 }
 
 #define XFS_SB_DADDR        ((xfs_daddr_t)0) /* daddr in filesystem/ag */
 #define XFS_SB_BLOCK(mp)    XFS_HDR_BLOCK(mp, XFS_SB_DADDR)
 
 #define XFS_HDR_BLOCK(mp,d) ((xfs_agblock_t)XFS_BB_TO_FSBT(mp,d))
 #define XFS_DADDR_TO_FSB(mp,d)  XFS_AGB_TO_FSB(mp, \
             xfs_daddr_to_agno(mp,d), xfs_daddr_to_agbno(mp,d))
 #define XFS_FSB_TO_DADDR(mp,fsbno)  XFS_AGB_TO_DADDR(mp, \
             XFS_FSB_TO_AGNO(mp,fsbno), XFS_FSB_TO_AGBNO(mp,fsbno))
 
 /*
  * File system sector to basic block conversions.
  */
 #define XFS_FSS_TO_BB(mp,sec)   ((sec) << (mp)->m_sectbb_log)
 
 /*
  * File system block to basic block conversions.
  */
 #define XFS_FSB_TO_BB(mp,fsbno) ((fsbno) << (mp)->m_blkbb_log)
 #define XFS_BB_TO_FSB(mp,bb)    \
     (((bb) + (XFS_FSB_TO_BB(mp,1) - 1)) >> (mp)->m_blkbb_log)
 #define XFS_BB_TO_FSBT(mp,bb)   ((bb) >> (mp)->m_blkbb_log)
 
 /*
  * File system block to byte conversions.
  */
 #define XFS_FSB_TO_B(mp,fsbno)  ((xfs_fsize_t)(fsbno) << (mp)->m_sb.sb_blocklog)
 #define XFS_B_TO_FSB(mp,b)  \
     ((((uint64_t)(b)) + (mp)->m_blockmask) >> (mp)->m_sb.sb_blocklog)
 #define XFS_B_TO_FSBT(mp,b) (((uint64_t)(b)) >> (mp)->m_sb.sb_blocklog)
 
 /*
  * Allocation group header
  *
  * This is divided into three structures, placed in sequential 512-byte
  * buffers after a copy of the superblock (also in a 512-byte buffer).
  */
 #define XFS_AGF_MAGIC   0x58414746  /* 'XAGF' */
 #define XFS_AGI_MAGIC   0x58414749  /* 'XAGI' */
 #define XFS_AGFL_MAGIC  0x5841464c  /* 'XAFL' */
 #define XFS_AGF_VERSION 1
 #define XFS_AGI_VERSION 1
 
 #define XFS_AGF_GOOD_VERSION(v) ((v) == XFS_AGF_VERSION)
 #define XFS_AGI_GOOD_VERSION(v) ((v) == XFS_AGI_VERSION)
 
 /*
  * Btree number 0 is bno, 1 is cnt, 2 is rmap. This value gives the size of the
  * arrays below.
  */
 #define XFS_BTNUM_AGF   ((int)XFS_BTNUM_RMAPi + 1)
 
 /*
  * The second word of agf_levels in the first a.g. overlaps the EFS
  * superblock's magic number.  Since the magic numbers valid for EFS
  * are > 64k, our value cannot be confused for an EFS superblock's.
  */
 
 typedef struct xfs_agf {
     /*
      * Common allocation group header information
      */
     __be32      agf_magicnum;   /* magic number == XFS_AGF_MAGIC */
     __be32      agf_versionnum; /* header version == XFS_AGF_VERSION */
     __be32      agf_seqno;  /* sequence # starting from 0 */
     __be32      agf_length; /* size in blocks of a.g. */
     /*
      * Freespace and rmap information
      */
     __be32      agf_roots[XFS_BTNUM_AGF];   /* root blocks */
     __be32      agf_levels[XFS_BTNUM_AGF];  /* btree levels */
 
     __be32      agf_flfirst;    /* first freelist block's index */
     __be32      agf_fllast; /* last freelist block's index */
     __be32      agf_flcount;    /* count of blocks in freelist */
     __be32      agf_freeblks;   /* total free blocks */
 
     __be32      agf_longest;    /* longest free space */
     __be32      agf_btreeblks;  /* # of blocks held in AGF btrees */
     uuid_t      agf_uuid;   /* uuid of filesystem */
 
     __be32      agf_rmap_blocks;    /* rmapbt blocks used */
     __be32      agf_refcount_blocks;    /* refcountbt blocks used */
 
     __be32      agf_refcount_root;  /* refcount tree root block */
     __be32      agf_refcount_level; /* refcount btree levels */
 
     /*
      * reserve some contiguous space for future logged fields before we add
      * the unlogged fields. This makes the range logging via flags and
      * structure offsets much simpler.
      */
     __be64      agf_spare64[14];
 
     /* unlogged fields, written during buffer writeback. */
     __be64      agf_lsn;    /* last write sequence */
     __be32      agf_crc;    /* crc of agf sector */
     __be32      agf_spare2;
 
     /* structure must be padded to 64 bit alignment */
 } xfs_agf_t;
 
 #define XFS_AGF_CRC_OFF     offsetof(struct xfs_agf, agf_crc)
 
 #define XFS_AGF_MAGICNUM    (1u << 0)
 #define XFS_AGF_VERSIONNUM  (1u << 1)
 #define XFS_AGF_SEQNO       (1u << 2)
 #define XFS_AGF_LENGTH      (1u << 3)
 #define XFS_AGF_ROOTS       (1u << 4)
 #define XFS_AGF_LEVELS      (1u << 5)
 #define XFS_AGF_FLFIRST     (1u << 6)
 #define XFS_AGF_FLLAST      (1u << 7)
 #define XFS_AGF_FLCOUNT     (1u << 8)
 #define XFS_AGF_FREEBLKS    (1u << 9)
 #define XFS_AGF_LONGEST     (1u << 10)
 #define XFS_AGF_BTREEBLKS   (1u << 11)
 #define XFS_AGF_UUID        (1u << 12)
 #define XFS_AGF_RMAP_BLOCKS (1u << 13)
 #define XFS_AGF_REFCOUNT_BLOCKS (1u << 14)
 #define XFS_AGF_REFCOUNT_ROOT   (1u << 15)
 #define XFS_AGF_REFCOUNT_LEVEL  (1u << 16)
 #define XFS_AGF_SPARE64     (1u << 17)
 #define XFS_AGF_NUM_BITS    18
 #define XFS_AGF_ALL_BITS    ((1u << XFS_AGF_NUM_BITS) - 1)
 
 #define XFS_AGF_FLAGS \
     { XFS_AGF_MAGICNUM, "MAGICNUM" }, \
     { XFS_AGF_VERSIONNUM,   "VERSIONNUM" }, \
     { XFS_AGF_SEQNO,    "SEQNO" }, \
     { XFS_AGF_LENGTH,   "LENGTH" }, \
     { XFS_AGF_ROOTS,    "ROOTS" }, \
     { XFS_AGF_LEVELS,   "LEVELS" }, \
     { XFS_AGF_FLFIRST,  "FLFIRST" }, \
     { XFS_AGF_FLLAST,   "FLLAST" }, \
     { XFS_AGF_FLCOUNT,  "FLCOUNT" }, \
     { XFS_AGF_FREEBLKS, "FREEBLKS" }, \
     { XFS_AGF_LONGEST,  "LONGEST" }, \
     { XFS_AGF_BTREEBLKS,    "BTREEBLKS" }, \
     { XFS_AGF_UUID,     "UUID" }, \
     { XFS_AGF_RMAP_BLOCKS,  "RMAP_BLOCKS" }, \
     { XFS_AGF_REFCOUNT_BLOCKS,  "REFCOUNT_BLOCKS" }, \
     { XFS_AGF_REFCOUNT_ROOT,    "REFCOUNT_ROOT" }, \
     { XFS_AGF_REFCOUNT_LEVEL,   "REFCOUNT_LEVEL" }, \
     { XFS_AGF_SPARE64,  "SPARE64" }
 
 /* disk block (xfs_daddr_t) in the AG */
 #define XFS_AGF_DADDR(mp)   ((xfs_daddr_t)(1 << (mp)->m_sectbb_log))
 #define XFS_AGF_BLOCK(mp)   XFS_HDR_BLOCK(mp, XFS_AGF_DADDR(mp))
 
 /*
  * Size of the unlinked inode hash table in the agi.
  */
 #define XFS_AGI_UNLINKED_BUCKETS    64
 
 typedef struct xfs_agi {
     /*
      * Common allocation group header information
      */
     __be32      agi_magicnum;   /* magic number == XFS_AGI_MAGIC */
     __be32      agi_versionnum; /* header version == XFS_AGI_VERSION */
     __be32      agi_seqno;  /* sequence # starting from 0 */
     __be32      agi_length; /* size in blocks of a.g. */
     /*
      * Inode information
      * Inodes are mapped by interpreting the inode number, so no
      * mapping data is needed here.
      */
     __be32      agi_count;  /* count of allocated inodes */
     __be32      agi_root;   /* root of inode btree */
     __be32      agi_level;  /* levels in inode btree */
     __be32      agi_freecount;  /* number of free inodes */
 
     __be32      agi_newino; /* new inode just allocated */
     __be32      agi_dirino; /* last directory inode chunk */
     /*
      * Hash table of inodes which have been unlinked but are
      * still being referenced.
      */
     __be32      agi_unlinked[XFS_AGI_UNLINKED_BUCKETS];
     /*
      * This marks the end of logging region 1 and start of logging region 2.
      */
     uuid_t      agi_uuid;   /* uuid of filesystem */
     __be32      agi_crc;    /* crc of agi sector */
     __be32      agi_pad32;
     __be64      agi_lsn;    /* last write sequence */
 
     __be32      agi_free_root; /* root of the free inode btree */
     __be32      agi_free_level;/* levels in free inode btree */
 
     __be32      agi_iblocks;    /* inobt blocks used */
     __be32      agi_fblocks;    /* finobt blocks used */
 
     /* structure must be padded to 64 bit alignment */
 } xfs_agi_t;
 
 #define XFS_AGI_CRC_OFF     offsetof(struct xfs_agi, agi_crc)
 
 #define XFS_AGI_MAGICNUM    (1u << 0)
 #define XFS_AGI_VERSIONNUM  (1u << 1)
 #define XFS_AGI_SEQNO       (1u << 2)
 #define XFS_AGI_LENGTH      (1u << 3)
 #define XFS_AGI_COUNT       (1u << 4)
 #define XFS_AGI_ROOT        (1u << 5)
 #define XFS_AGI_LEVEL       (1u << 6)
 #define XFS_AGI_FREECOUNT   (1u << 7)
 #define XFS_AGI_NEWINO      (1u << 8)
 #define XFS_AGI_DIRINO      (1u << 9)
 #define XFS_AGI_UNLINKED    (1u << 10)
 #define XFS_AGI_NUM_BITS_R1 11  /* end of the 1st agi logging region */
 #define XFS_AGI_ALL_BITS_R1 ((1u << XFS_AGI_NUM_BITS_R1) - 1)
 #define XFS_AGI_FREE_ROOT   (1u << 11)
 #define XFS_AGI_FREE_LEVEL  (1u << 12)
 #define XFS_AGI_IBLOCKS     (1u << 13) /* both inobt/finobt block counters */
 #define XFS_AGI_NUM_BITS_R2 14
 
 /* disk block (xfs_daddr_t) in the AG */
 #define XFS_AGI_DADDR(mp)   ((xfs_daddr_t)(2 << (mp)->m_sectbb_log))
 #define XFS_AGI_BLOCK(mp)   XFS_HDR_BLOCK(mp, XFS_AGI_DADDR(mp))
 
 /*
  * The third a.g. block contains the a.g. freelist, an array
  * of block pointers to blocks owned by the allocation btree code.
  */
 #define XFS_AGFL_DADDR(mp)  ((xfs_daddr_t)(3 << (mp)->m_sectbb_log))
 #define XFS_AGFL_BLOCK(mp)  XFS_HDR_BLOCK(mp, XFS_AGFL_DADDR(mp))
 #define XFS_BUF_TO_AGFL(bp) ((struct xfs_agfl *)((bp)->b_addr))
 
 struct xfs_agfl {
     __be32      agfl_magicnum;
     __be32      agfl_seqno;
     uuid_t      agfl_uuid;
     __be64      agfl_lsn;
     __be32      agfl_crc;
 } __attribute__((packed));
 
 #define XFS_AGFL_CRC_OFF    offsetof(struct xfs_agfl, agfl_crc)
 
 #define XFS_AGB_TO_FSB(mp,agno,agbno)   \
     (((xfs_fsblock_t)(agno) << (mp)->m_sb.sb_agblklog) | (agbno))
 #define XFS_FSB_TO_AGNO(mp,fsbno)   \
     ((xfs_agnumber_t)((fsbno) >> (mp)->m_sb.sb_agblklog))
 #define XFS_FSB_TO_AGBNO(mp,fsbno)  \
     ((xfs_agblock_t)((fsbno) & xfs_mask32lo((mp)->m_sb.sb_agblklog)))
 #define XFS_AGB_TO_DADDR(mp,agno,agbno) \
     ((xfs_daddr_t)XFS_FSB_TO_BB(mp, \
         (xfs_fsblock_t)(agno) * (mp)->m_sb.sb_agblocks + (agbno)))
 #define XFS_AG_DADDR(mp,agno,d)     (XFS_AGB_TO_DADDR(mp, agno, 0) + (d))
 
 /*
  * For checking for bad ranges of xfs_daddr_t's, covering multiple
  * allocation groups or a single xfs_daddr_t that's a superblock copy.
  */
 #define XFS_AG_CHECK_DADDR(mp,d,len)    \
     ((len) == 1 ? \
         ASSERT((d) == XFS_SB_DADDR || \
            xfs_daddr_to_agbno(mp, d) != XFS_SB_DADDR) : \
         ASSERT(xfs_daddr_to_agno(mp, d) == \
            xfs_daddr_to_agno(mp, (d) + (len) - 1)))
 
 /*
  * XFS Timestamps
  * ==============
  *
  * Traditional ondisk inode timestamps consist of signed 32-bit counters for
  * seconds and nanoseconds; time zero is the Unix epoch, Jan  1 00:00:00 UTC
  * 1970, which means that the timestamp epoch is the same as the Unix epoch.
  * Therefore, the ondisk min and max defined here can be used directly to
  * constrain the incore timestamps on a Unix system.  Note that we actually
  * encode a __be64 value on disk.
  *
  * When the bigtime feature is enabled, ondisk inode timestamps become an
  * unsigned 64-bit nanoseconds counter.  This means that the bigtime inode
  * timestamp epoch is the start of the classic timestamp range, which is
  * Dec 13 20:45:52 UTC 1901.  Because the epochs are not the same, callers
  * /must/ use the bigtime conversion functions when encoding and decoding raw
  * timestamps.
  */
 typedef __be64 xfs_timestamp_t;
 
 /* Legacy timestamp encoding format. */
 struct xfs_legacy_timestamp {
     __be32      t_sec;      /* timestamp seconds */
     __be32      t_nsec;     /* timestamp nanoseconds */
 };
 
 /*
  * Smallest possible ondisk seconds value with traditional timestamps.  This
  * corresponds exactly with the incore timestamp Dec 13 20:45:52 UTC 1901.
  */
 #define XFS_LEGACY_TIME_MIN ((int64_t)S32_MIN)
 
 /*
  * Largest possible ondisk seconds value with traditional timestamps.  This
  * corresponds exactly with the incore timestamp Jan 19 03:14:07 UTC 2038.
  */
 #define XFS_LEGACY_TIME_MAX ((int64_t)S32_MAX)
 
 /*
  * Smallest possible ondisk seconds value with bigtime timestamps.  This
  * corresponds (after conversion to a Unix timestamp) with the traditional
  * minimum timestamp of Dec 13 20:45:52 UTC 1901.
  */
 #define XFS_BIGTIME_TIME_MIN    ((int64_t)0)
 
 /*
  * Largest supported ondisk seconds value with bigtime timestamps.  This
  * corresponds (after conversion to a Unix timestamp) with an incore timestamp
  * of Jul  2 20:20:24 UTC 2486.
  *
  * We round down the ondisk limit so that the bigtime quota and inode max
  * timestamps will be the same.
  */
 #define XFS_BIGTIME_TIME_MAX    ((int64_t)((-1ULL / NSEC_PER_SEC) & ~0x3ULL))
 
 /*
  * Bigtime epoch is set exactly to the minimum time value that a traditional
  * 32-bit timestamp can represent when using the Unix epoch as a reference.
  * Hence the Unix epoch is at a fixed offset into the supported bigtime
  * timestamp range.
  *
  * The bigtime epoch also matches the minimum value an on-disk 32-bit XFS
  * timestamp can represent so we will not lose any fidelity in converting
  * to/from unix and bigtime timestamps.
  *
  * The following conversion factor converts a seconds counter from the Unix
  * epoch to the bigtime epoch.
  */
 #define XFS_BIGTIME_EPOCH_OFFSET    (-(int64_t)S32_MIN)
 
 /* Convert a timestamp from the Unix epoch to the bigtime epoch. */
 static inline uint64_t xfs_unix_to_bigtime(time64_t unix_seconds)
 {
     return (uint64_t)unix_seconds + XFS_BIGTIME_EPOCH_OFFSET;
 }
 
 /* Convert a timestamp from the bigtime epoch to the Unix epoch. */
 static inline time64_t xfs_bigtime_to_unix(uint64_t ondisk_seconds)
 {
     return (time64_t)ondisk_seconds - XFS_BIGTIME_EPOCH_OFFSET;
 }
 
 /*
  * On-disk inode structure.
  *
  * This is just the header or "dinode core", the inode is expanded to fill a
  * variable size the leftover area split into a data and an attribute fork.
  * The format of the data and attribute fork depends on the format of the
  * inode as indicated by di_format and di_aformat.  To access the data and
  * attribute use the XFS_DFORK_DPTR, XFS_DFORK_APTR, and XFS_DFORK_PTR macros
  * below.
  *
  * There is a very similar struct xfs_log_dinode which matches the layout of
  * this structure, but is kept in native format instead of big endian.
  *
  * Note: di_flushiter is only used by v1/2 inodes - it's effectively a zeroed
  * padding field for v3 inodes.
  */
 #define XFS_DINODE_MAGIC        0x494e  /* 'IN' */
 struct xfs_dinode {
     __be16      di_magic;   /* inode magic # = XFS_DINODE_MAGIC */
     __be16      di_mode;    /* mode and type of file */
     __u8        di_version; /* inode version */
     __u8        di_format;  /* format of di_c data */
     __be16      di_onlink;  /* old number of links to file */
     __be32      di_uid;     /* owner's user id */
     __be32      di_gid;     /* owner's group id */
     __be32      di_nlink;   /* number of links to file */
     __be16      di_projid_lo;   /* lower part of owner's project id */
     __be16      di_projid_hi;   /* higher part owner's project id */
     union {
         /* Number of data fork extents if NREXT64 is set */
         __be64  di_big_nextents;
 
         /* Padding for V3 inodes without NREXT64 set. */
         __be64  di_v3_pad;
 
         /* Padding and inode flush counter for V2 inodes. */
         struct {
             __u8    di_v2_pad[6];
             __be16  di_flushiter;
         };
     };
     xfs_timestamp_t di_atime;   /* time last accessed */
     xfs_timestamp_t di_mtime;   /* time last modified */
     xfs_timestamp_t di_ctime;   /* time created/inode modified */
     __be64      di_size;    /* number of bytes in file */
     __be64      di_nblocks; /* # of direct & btree blocks used */
     __be32      di_extsize; /* basic/minimum extent size for file */
     union {
         /*
          * For V2 inodes and V3 inodes without NREXT64 set, this
          * is the number of data and attr fork extents.
          */
         struct {
             __be32  di_nextents;
             __be16  di_anextents;
         } __packed;
 
         /* Number of attr fork extents if NREXT64 is set. */
         struct {
             __be32  di_big_anextents;
             __be16  di_nrext64_pad;
         } __packed;
     } __packed;
     __u8        di_forkoff; /* attr fork offs, <<3 for 64b align */
     __s8        di_aformat; /* format of attr fork's data */
     __be32      di_dmevmask;    /* DMIG event mask */
     __be16      di_dmstate; /* DMIG state info */
     __be16      di_flags;   /* random flags, XFS_DIFLAG_... */
     __be32      di_gen;     /* generation number */
 
     /* di_next_unlinked is the only non-core field in the old dinode */
     __be32      di_next_unlinked;/* agi unlinked list ptr */
 
     /* start of the extended dinode, writable fields */
     __le32      di_crc;     /* CRC of the inode */
     __be64      di_changecount; /* number of attribute changes */
     __be64      di_lsn;     /* flush sequence */
     __be64      di_flags2;  /* more random flags */
     __be32      di_cowextsize;  /* basic cow extent size for file */
     __u8        di_pad2[12];    /* more padding for future expansion */
 
     /* fields only written to during inode creation */
     xfs_timestamp_t di_crtime;  /* time created */
     __be64      di_ino;     /* inode number */
     uuid_t      di_uuid;    /* UUID of the filesystem */
 
     /* structure must be padded to 64 bit alignment */
 };
 
 #define XFS_DINODE_CRC_OFF  offsetof(struct xfs_dinode, di_crc)
 
 #define DI_MAX_FLUSH 0xffff
 
 /*
  * Size of the core inode on disk.  Version 1 and 2 inodes have
  * the same size, but version 3 has grown a few additional fields.
  */
 static inline uint xfs_dinode_size(int version)
 {
     if (version == 3)
         return sizeof(struct xfs_dinode);
     return offsetof(struct xfs_dinode, di_crc);
 }
 
 /*
  * The 32 bit link count in the inode theoretically maxes out at UINT_MAX.
  * Since the pathconf interface is signed, we use 2^31 - 1 instead.
  */
 #define XFS_MAXLINK     ((1U << 31) - 1U)
 
 /*
  * Values for di_format
  *
  * This enum is used in string mapping in xfs_trace.h; please keep the
  * TRACE_DEFINE_ENUMs for it up to date.
  */
 enum xfs_dinode_fmt {
     XFS_DINODE_FMT_DEV,     /* xfs_dev_t */
     XFS_DINODE_FMT_LOCAL,       /* bulk data */
     XFS_DINODE_FMT_EXTENTS,     /* struct xfs_bmbt_rec */
     XFS_DINODE_FMT_BTREE,       /* struct xfs_bmdr_block */
     XFS_DINODE_FMT_UUID     /* added long ago, but never used */
 };
 
 #define XFS_INODE_FORMAT_STR \
     { XFS_DINODE_FMT_DEV,       "dev" }, \
     { XFS_DINODE_FMT_LOCAL,     "local" }, \
     { XFS_DINODE_FMT_EXTENTS,   "extent" }, \
     { XFS_DINODE_FMT_BTREE,     "btree" }, \
     { XFS_DINODE_FMT_UUID,      "uuid" }
 
 /*
  * Max values for extnum and aextnum.
  *
  * The original on-disk extent counts were held in signed fields, resulting in
  * maximum extent counts of 2^31 and 2^15 for the data and attr forks
  * respectively. Similarly the maximum extent length is limited to 2^21 blocks
  * by the 21-bit wide blockcount field of a BMBT extent record.
  *
  * The newly introduced data fork extent counter can hold a 64-bit value,
  * however the maximum number of extents in a file is also limited to 2^54
  * extents by the 54-bit wide startoff field of a BMBT extent record.
  *
  * It is further limited by the maximum supported file size of 2^63
  * *bytes*. This leads to a maximum extent count for maximally sized filesystem
  * blocks (64kB) of:
  *
  * 2^63 bytes / 2^16 bytes per block = 2^47 blocks
  *
  * Rounding up 47 to the nearest multiple of bits-per-byte results in 48. Hence
  * 2^48 was chosen as the maximum data fork extent count.
  *
  * The maximum file size that can be represented by the data fork extent counter
  * in the worst case occurs when all extents are 1 block in length and each
  * block is 1KB in size.
  *
  * With XFS_MAX_EXTCNT_DATA_FORK_SMALL representing maximum extent count and
  * with 1KB sized blocks, a file can reach upto,
  * 1KB * (2^31) = 2TB
  *
  * This is much larger than the theoretical maximum size of a directory
  * i.e. XFS_DIR2_SPACE_SIZE * XFS_DIR2_MAX_SPACES = ~96GB.
  *
  * Hence, a directory inode can never overflow its data fork extent counter.
  */
 #define XFS_MAX_EXTCNT_DATA_FORK_LARGE  ((xfs_extnum_t)((1ULL << 48) - 1))
 #define XFS_MAX_EXTCNT_ATTR_FORK_LARGE  ((xfs_extnum_t)((1ULL << 32) - 1))
 #define XFS_MAX_EXTCNT_DATA_FORK_SMALL  ((xfs_extnum_t)((1ULL << 31) - 1))
 #define XFS_MAX_EXTCNT_ATTR_FORK_SMALL  ((xfs_extnum_t)((1ULL << 15) - 1))
 
 /*
  * When we upgrade an inode to the large extent counts, the maximum value by
  * which the extent count can increase is bound by the change in size of the
  * on-disk field. No upgrade operation should ever be adding more than a few
  * tens of extents, so if we get a really large value it is a sign of a code bug
  * or corruption.
  */
 #define XFS_MAX_EXTCNT_UPGRADE_NR   \
     min(XFS_MAX_EXTCNT_ATTR_FORK_LARGE - XFS_MAX_EXTCNT_ATTR_FORK_SMALL,    \
         XFS_MAX_EXTCNT_DATA_FORK_LARGE - XFS_MAX_EXTCNT_DATA_FORK_SMALL)
 
 /*
  * Inode minimum and maximum sizes.
  */
 #define XFS_DINODE_MIN_LOG  8
 #define XFS_DINODE_MAX_LOG  11
 #define XFS_DINODE_MIN_SIZE (1 << XFS_DINODE_MIN_LOG)
 #define XFS_DINODE_MAX_SIZE (1 << XFS_DINODE_MAX_LOG)
 
 /*
  * Inode size for given fs.
  */
 #define XFS_DINODE_SIZE(mp) \
     (xfs_has_v3inodes(mp) ? \
         sizeof(struct xfs_dinode) : \
         offsetof(struct xfs_dinode, di_crc))
 #define XFS_LITINO(mp) \
     ((mp)->m_sb.sb_inodesize - XFS_DINODE_SIZE(mp))
 
 /*
  * Inode data & attribute fork sizes, per inode.
  */
 #define XFS_DFORK_BOFF(dip)     ((int)((dip)->di_forkoff << 3))
 
 #define XFS_DFORK_DSIZE(dip,mp) \
     ((dip)->di_forkoff ? XFS_DFORK_BOFF(dip) : XFS_LITINO(mp))
 #define XFS_DFORK_ASIZE(dip,mp) \
     ((dip)->di_forkoff ? XFS_LITINO(mp) - XFS_DFORK_BOFF(dip) : 0)
 #define XFS_DFORK_SIZE(dip,mp,w) \
     ((w) == XFS_DATA_FORK ? \
         XFS_DFORK_DSIZE(dip, mp) : \
         XFS_DFORK_ASIZE(dip, mp))
 
 #define XFS_DFORK_MAXEXT(dip, mp, w) \
     (XFS_DFORK_SIZE(dip, mp, w) / sizeof(struct xfs_bmbt_rec))
 
 /*
  * Return pointers to the data or attribute forks.
  */
 #define XFS_DFORK_DPTR(dip) \
     ((char *)dip + xfs_dinode_size(dip->di_version))
 #define XFS_DFORK_APTR(dip) \
     (XFS_DFORK_DPTR(dip) + XFS_DFORK_BOFF(dip))
 #define XFS_DFORK_PTR(dip,w)    \
     ((w) == XFS_DATA_FORK ? XFS_DFORK_DPTR(dip) : XFS_DFORK_APTR(dip))
 
 #define XFS_DFORK_FORMAT(dip,w) \
     ((w) == XFS_DATA_FORK ? \
         (dip)->di_format : \
         (dip)->di_aformat)
 
 /*
  * For block and character special files the 32bit dev_t is stored at the
  * beginning of the data fork.
  */
 static inline xfs_dev_t xfs_dinode_get_rdev(struct xfs_dinode *dip)
 {
     return be32_to_cpu(*(__be32 *)XFS_DFORK_DPTR(dip));
 }
 
 static inline void xfs_dinode_put_rdev(struct xfs_dinode *dip, xfs_dev_t rdev)
 {
     *(__be32 *)XFS_DFORK_DPTR(dip) = cpu_to_be32(rdev);
 }
 
 /*
  * Values for di_flags
  */
 #define XFS_DIFLAG_REALTIME_BIT  0  /* file's blocks come from rt area */
 #define XFS_DIFLAG_PREALLOC_BIT  1  /* file space has been preallocated */
 #define XFS_DIFLAG_NEWRTBM_BIT   2  /* for rtbitmap inode, new format */
 #define XFS_DIFLAG_IMMUTABLE_BIT 3  /* inode is immutable */
 #define XFS_DIFLAG_APPEND_BIT    4  /* inode is append-only */
 #define XFS_DIFLAG_SYNC_BIT      5  /* inode is written synchronously */
 #define XFS_DIFLAG_NOATIME_BIT   6  /* do not update atime */
 #define XFS_DIFLAG_NODUMP_BIT    7  /* do not dump */
 #define XFS_DIFLAG_RTINHERIT_BIT 8  /* create with realtime bit set */
 #define XFS_DIFLAG_PROJINHERIT_BIT   9  /* create with parents projid */
 #define XFS_DIFLAG_NOSYMLINKS_BIT   10  /* disallow symlink creation */
 #define XFS_DIFLAG_EXTSIZE_BIT      11  /* inode extent size allocator hint */
 #define XFS_DIFLAG_EXTSZINHERIT_BIT 12  /* inherit inode extent size */
 #define XFS_DIFLAG_NODEFRAG_BIT     13  /* do not reorganize/defragment */
 #define XFS_DIFLAG_FILESTREAM_BIT   14  /* use filestream allocator */
 /* Do not use bit 15, di_flags is legacy and unchanging now */
 
 #define XFS_DIFLAG_REALTIME      (1 << XFS_DIFLAG_REALTIME_BIT)
 #define XFS_DIFLAG_PREALLOC      (1 << XFS_DIFLAG_PREALLOC_BIT)
 #define XFS_DIFLAG_NEWRTBM       (1 << XFS_DIFLAG_NEWRTBM_BIT)
 #define XFS_DIFLAG_IMMUTABLE     (1 << XFS_DIFLAG_IMMUTABLE_BIT)
 #define XFS_DIFLAG_APPEND        (1 << XFS_DIFLAG_APPEND_BIT)
 #define XFS_DIFLAG_SYNC          (1 << XFS_DIFLAG_SYNC_BIT)
 #define XFS_DIFLAG_NOATIME       (1 << XFS_DIFLAG_NOATIME_BIT)
 #define XFS_DIFLAG_NODUMP        (1 << XFS_DIFLAG_NODUMP_BIT)
 #define XFS_DIFLAG_RTINHERIT     (1 << XFS_DIFLAG_RTINHERIT_BIT)
 #define XFS_DIFLAG_PROJINHERIT   (1 << XFS_DIFLAG_PROJINHERIT_BIT)
 #define XFS_DIFLAG_NOSYMLINKS    (1 << XFS_DIFLAG_NOSYMLINKS_BIT)
 #define XFS_DIFLAG_EXTSIZE       (1 << XFS_DIFLAG_EXTSIZE_BIT)
 #define XFS_DIFLAG_EXTSZINHERIT  (1 << XFS_DIFLAG_EXTSZINHERIT_BIT)
 #define XFS_DIFLAG_NODEFRAG      (1 << XFS_DIFLAG_NODEFRAG_BIT)
 #define XFS_DIFLAG_FILESTREAM    (1 << XFS_DIFLAG_FILESTREAM_BIT)
 
 #define XFS_DIFLAG_ANY \
     (XFS_DIFLAG_REALTIME | XFS_DIFLAG_PREALLOC | XFS_DIFLAG_NEWRTBM | \
      XFS_DIFLAG_IMMUTABLE | XFS_DIFLAG_APPEND | XFS_DIFLAG_SYNC | \
      XFS_DIFLAG_NOATIME | XFS_DIFLAG_NODUMP | XFS_DIFLAG_RTINHERIT | \
      XFS_DIFLAG_PROJINHERIT | XFS_DIFLAG_NOSYMLINKS | XFS_DIFLAG_EXTSIZE | \
      XFS_DIFLAG_EXTSZINHERIT | XFS_DIFLAG_NODEFRAG | XFS_DIFLAG_FILESTREAM)
 
 /*
  * Values for di_flags2 These start by being exposed to userspace in the upper
  * 16 bits of the XFS_XFLAG_s range.
  */
 #define XFS_DIFLAG2_DAX_BIT 0   /* use DAX for this inode */
 #define XFS_DIFLAG2_REFLINK_BIT 1   /* file's blocks may be shared */
 #define XFS_DIFLAG2_COWEXTSIZE_BIT   2  /* copy on write extent size hint */
 #define XFS_DIFLAG2_BIGTIME_BIT 3   /* big timestamps */
 #define XFS_DIFLAG2_NREXT64_BIT 4   /* large extent counters */
 
 #define XFS_DIFLAG2_DAX     (1 << XFS_DIFLAG2_DAX_BIT)
 #define XFS_DIFLAG2_REFLINK     (1 << XFS_DIFLAG2_REFLINK_BIT)
 #define XFS_DIFLAG2_COWEXTSIZE  (1 << XFS_DIFLAG2_COWEXTSIZE_BIT)
 #define XFS_DIFLAG2_BIGTIME (1 << XFS_DIFLAG2_BIGTIME_BIT)
 #define XFS_DIFLAG2_NREXT64 (1 << XFS_DIFLAG2_NREXT64_BIT)
 
 #define XFS_DIFLAG2_ANY \
     (XFS_DIFLAG2_DAX | XFS_DIFLAG2_REFLINK | XFS_DIFLAG2_COWEXTSIZE | \
      XFS_DIFLAG2_BIGTIME | XFS_DIFLAG2_NREXT64)
 
 static inline bool xfs_dinode_has_bigtime(const struct xfs_dinode *dip)
 {
     return dip->di_version >= 3 &&
            (dip->di_flags2 & cpu_to_be64(XFS_DIFLAG2_BIGTIME));
 }
 
 static inline bool xfs_dinode_has_large_extent_counts(
     const struct xfs_dinode *dip)
 {
     return dip->di_version >= 3 &&
            (dip->di_flags2 & cpu_to_be64(XFS_DIFLAG2_NREXT64));
 }
 
 /*
  * Inode number format:
  * low inopblog bits - offset in block
  * next agblklog bits - block number in ag
  * next agno_log bits - ag number
  * high agno_log-agblklog-inopblog bits - 0
  */
 #define XFS_INO_MASK(k)         (uint32_t)((1ULL << (k)) - 1)
 #define XFS_INO_OFFSET_BITS(mp)     (mp)->m_sb.sb_inopblog
 #define XFS_INO_AGBNO_BITS(mp)      (mp)->m_sb.sb_agblklog
 #define XFS_INO_AGINO_BITS(mp)      ((mp)->m_ino_geo.agino_log)
 #define XFS_INO_AGNO_BITS(mp)       (mp)->m_agno_log
 #define XFS_INO_BITS(mp)        \
     XFS_INO_AGNO_BITS(mp) + XFS_INO_AGINO_BITS(mp)
 #define XFS_INO_TO_AGNO(mp,i)       \
     ((xfs_agnumber_t)((i) >> XFS_INO_AGINO_BITS(mp)))
 #define XFS_INO_TO_AGINO(mp,i)      \
     ((xfs_agino_t)(i) & XFS_INO_MASK(XFS_INO_AGINO_BITS(mp)))
 #define XFS_INO_TO_AGBNO(mp,i)      \
     (((xfs_agblock_t)(i) >> XFS_INO_OFFSET_BITS(mp)) & \
         XFS_INO_MASK(XFS_INO_AGBNO_BITS(mp)))
 #define XFS_INO_TO_OFFSET(mp,i)     \
     ((int)(i) & XFS_INO_MASK(XFS_INO_OFFSET_BITS(mp)))
 #define XFS_INO_TO_FSB(mp,i)        \
     XFS_AGB_TO_FSB(mp, XFS_INO_TO_AGNO(mp,i), XFS_INO_TO_AGBNO(mp,i))
 #define XFS_AGINO_TO_INO(mp,a,i)    \
     (((xfs_ino_t)(a) << XFS_INO_AGINO_BITS(mp)) | (i))
 #define XFS_AGINO_TO_AGBNO(mp,i)    ((i) >> XFS_INO_OFFSET_BITS(mp))
 #define XFS_AGINO_TO_OFFSET(mp,i)   \
     ((i) & XFS_INO_MASK(XFS_INO_OFFSET_BITS(mp)))
 #define XFS_OFFBNO_TO_AGINO(mp,b,o) \
     ((xfs_agino_t)(((b) << XFS_INO_OFFSET_BITS(mp)) | (o)))
 #define XFS_FSB_TO_INO(mp, b)   ((xfs_ino_t)((b) << XFS_INO_OFFSET_BITS(mp)))
 #define XFS_AGB_TO_AGINO(mp, b) ((xfs_agino_t)((b) << XFS_INO_OFFSET_BITS(mp)))
 
 #define XFS_MAXINUMBER      ((xfs_ino_t)((1ULL << 56) - 1ULL))
 #define XFS_MAXINUMBER_32   ((xfs_ino_t)((1ULL << 32) - 1ULL))
 
 /*
  * RealTime Device format definitions
  */
 
 /* Min and max rt extent sizes, specified in bytes */
 #define XFS_MAX_RTEXTSIZE   (1024 * 1024 * 1024)    /* 1GB */
 #define XFS_DFL_RTEXTSIZE   (64 * 1024)         /* 64kB */
 #define XFS_MIN_RTEXTSIZE   (4 * 1024)      /* 4kB */
 
 #define XFS_BLOCKSIZE(mp)   ((mp)->m_sb.sb_blocksize)
 #define XFS_BLOCKMASK(mp)   ((mp)->m_blockmask)
 #define XFS_BLOCKWSIZE(mp)  ((mp)->m_blockwsize)
 #define XFS_BLOCKWMASK(mp)  ((mp)->m_blockwmask)
 
 /*
  * RT Summary and bit manipulation macros.
  */
 #define XFS_SUMOFFS(mp,ls,bb)   ((int)((ls) * (mp)->m_sb.sb_rbmblocks + (bb)))
 #define XFS_SUMOFFSTOBLOCK(mp,s)    \
     (((s) * (uint)sizeof(xfs_suminfo_t)) >> (mp)->m_sb.sb_blocklog)
 #define XFS_SUMPTR(mp,bp,so)    \
     ((xfs_suminfo_t *)((bp)->b_addr + \
         (((so) * (uint)sizeof(xfs_suminfo_t)) & XFS_BLOCKMASK(mp))))
 
 #define XFS_BITTOBLOCK(mp,bi)   ((bi) >> (mp)->m_blkbit_log)
 #define XFS_BLOCKTOBIT(mp,bb)   ((bb) << (mp)->m_blkbit_log)
 #define XFS_BITTOWORD(mp,bi)    \
     ((int)(((bi) >> XFS_NBWORDLOG) & XFS_BLOCKWMASK(mp)))
 
 #define XFS_RTMIN(a,b)  ((a) < (b) ? (a) : (b))
 #define XFS_RTMAX(a,b)  ((a) > (b) ? (a) : (b))
 
 #define XFS_RTLOBIT(w)  xfs_lowbit32(w)
 #define XFS_RTHIBIT(w)  xfs_highbit32(w)
 
 #define XFS_RTBLOCKLOG(b)   xfs_highbit64(b)
 
 /*
  * Dquot and dquot block format definitions
  */
 #define XFS_DQUOT_MAGIC     0x4451      /* 'DQ' */
 #define XFS_DQUOT_VERSION   (uint8_t)0x01   /* latest version number */
 
 #define XFS_DQTYPE_USER     (1u << 0)   /* user dquot record */
 #define XFS_DQTYPE_PROJ     (1u << 1)   /* project dquot record */
 #define XFS_DQTYPE_GROUP    (1u << 2)   /* group dquot record */
 #define XFS_DQTYPE_BIGTIME  (1u << 7)   /* large expiry timestamps */
 
 /* bitmask to determine if this is a user/group/project dquot */
 #define XFS_DQTYPE_REC_MASK (XFS_DQTYPE_USER | \
                  XFS_DQTYPE_PROJ | \
                  XFS_DQTYPE_GROUP)
 
 #define XFS_DQTYPE_ANY      (XFS_DQTYPE_REC_MASK | \
                  XFS_DQTYPE_BIGTIME)
 
 /*
  * XFS Quota Timers
  * ================
  *
  * Traditional quota grace period expiration timers are an unsigned 32-bit
  * seconds counter; time zero is the Unix epoch, Jan  1 00:00:01 UTC 1970.
  * Note that an expiration value of zero means that the quota limit has not
  * been reached, and therefore no expiration has been set.  Therefore, the
  * ondisk min and max defined here can be used directly to constrain the incore
  * quota expiration timestamps on a Unix system.
  *
  * When bigtime is enabled, we trade two bits of precision to expand the
  * expiration timeout range to match that of big inode timestamps.  The min and
  * max recorded here are the on-disk limits, not a Unix timestamp.
  *
  * The grace period for each quota type is stored in the root dquot (id = 0)
  * and is applied to a non-root dquot when it exceeds the soft or hard limits.
  * The length of quota grace periods are unsigned 32-bit quantities measured in
  * units of seconds.  A value of zero means to use the default period.
  */
 
 /*
  * Smallest possible ondisk quota expiration value with traditional timestamps.
  * This corresponds exactly with the incore expiration Jan  1 00:00:01 UTC 1970.
  */
 #define XFS_DQ_LEGACY_EXPIRY_MIN    ((int64_t)1)
 
 /*
  * Largest possible ondisk quota expiration value with traditional timestamps.
  * This corresponds exactly with the incore expiration Feb  7 06:28:15 UTC 2106.
  */
 #define XFS_DQ_LEGACY_EXPIRY_MAX    ((int64_t)U32_MAX)
 
 /*
  * Smallest possible ondisk quota expiration value with bigtime timestamps.
  * This corresponds (after conversion to a Unix timestamp) with the incore
  * expiration of Jan  1 00:00:04 UTC 1970.
  */
 #define XFS_DQ_BIGTIME_EXPIRY_MIN   (XFS_DQ_LEGACY_EXPIRY_MIN)
 
 /*
  * Largest supported ondisk quota expiration value with bigtime timestamps.
  * This corresponds (after conversion to a Unix timestamp) with an incore
  * expiration of Jul  2 20:20:24 UTC 2486.
  *
  * The ondisk field supports values up to -1U, which corresponds to an incore
  * expiration in 2514.  This is beyond the maximum the bigtime inode timestamp,
  * so we cap the maximum bigtime quota expiration to the max inode timestamp.
  */
 #define XFS_DQ_BIGTIME_EXPIRY_MAX   ((int64_t)4074815106U)
 
 /*
  * The following conversion factors assist in converting a quota expiration
  * timestamp between the incore and ondisk formats.
  */
 #define XFS_DQ_BIGTIME_SHIFT    (2)
 #define XFS_DQ_BIGTIME_SLACK    ((int64_t)(1ULL << XFS_DQ_BIGTIME_SHIFT) - 1)
 
 /* Convert an incore quota expiration timestamp to an ondisk bigtime value. */
 static inline uint32_t xfs_dq_unix_to_bigtime(time64_t unix_seconds)
 {
     /*
      * Round the expiration timestamp up to the nearest bigtime timestamp
      * that we can store, to give users the most time to fix problems.
      */
     return ((uint64_t)unix_seconds + XFS_DQ_BIGTIME_SLACK) >>
             XFS_DQ_BIGTIME_SHIFT;
 }
 
 /* Convert an ondisk bigtime quota expiration value to an incore timestamp. */
 static inline time64_t xfs_dq_bigtime_to_unix(uint32_t ondisk_seconds)
 {
     return (time64_t)ondisk_seconds << XFS_DQ_BIGTIME_SHIFT;
 }
 
 /*
  * Default quota grace periods, ranging from zero (use the compiled defaults)
  * to ~136 years.  These are applied to a non-root dquot that has exceeded
  * either limit.
  */
 #define XFS_DQ_GRACE_MIN        ((int64_t)0)
 #define XFS_DQ_GRACE_MAX        ((int64_t)U32_MAX)
 
 /*
  * This is the main portion of the on-disk representation of quota information
  * for a user.  We pad this with some more expansion room to construct the on
  * disk structure.
  */
 struct xfs_disk_dquot {
     __be16      d_magic;    /* dquot magic = XFS_DQUOT_MAGIC */
     __u8        d_version;  /* dquot version */
     __u8        d_type;     /* XFS_DQTYPE_USER/PROJ/GROUP */
     __be32      d_id;       /* user,project,group id */
     __be64      d_blk_hardlimit;/* absolute limit on disk blks */
     __be64      d_blk_softlimit;/* preferred limit on disk blks */
     __be64      d_ino_hardlimit;/* maximum # allocated inodes */
     __be64      d_ino_softlimit;/* preferred inode limit */
     __be64      d_bcount;   /* disk blocks owned by the user */
     __be64      d_icount;   /* inodes owned by the user */
     __be32      d_itimer;   /* zero if within inode limits if not,
                        this is when we refuse service */
     __be32      d_btimer;   /* similar to above; for disk blocks */
     __be16      d_iwarns;   /* warnings issued wrt num inodes */
     __be16      d_bwarns;   /* warnings issued wrt disk blocks */
     __be32      d_pad0;     /* 64 bit align */
     __be64      d_rtb_hardlimit;/* absolute limit on realtime blks */
     __be64      d_rtb_softlimit;/* preferred limit on RT disk blks */
     __be64      d_rtbcount; /* realtime blocks owned */
     __be32      d_rtbtimer; /* similar to above; for RT disk blocks */
     __be16      d_rtbwarns; /* warnings issued wrt RT disk blocks */
     __be16      d_pad;
 };
 
 /*
  * This is what goes on disk. This is separated from the xfs_disk_dquot because
  * carrying the unnecessary padding would be a waste of memory.
  */
 struct xfs_dqblk {
     struct xfs_disk_dquot   dd_diskdq; /* portion living incore as well */
     char            dd_fill[4];/* filling for posterity */
 
     /*
      * These two are only present on filesystems with the CRC bits set.
      */
     __be32        dd_crc;   /* checksum */
     __be64        dd_lsn;   /* last modification in log */
     uuid_t        dd_uuid;  /* location information */
 };
 
 #define XFS_DQUOT_CRC_OFF   offsetof(struct xfs_dqblk, dd_crc)
 
 /*
  * This defines the unit of allocation of dquots.
  *
  * Currently, it is just one file system block, and a 4K blk contains 30
  * (136 * 30 = 4080) dquots. It's probably not worth trying to make
  * this more dynamic.
  *
  * However, if this number is changed, we have to make sure that we don't
  * implicitly assume that we do allocations in chunks of a single filesystem
  * block in the dquot/xqm code.
  *
  * This is part of the ondisk format because the structure size is not a power
  * of two, which leaves slack at the end of the disk block.
  */
 #define XFS_DQUOT_CLUSTER_SIZE_FSB  (xfs_filblks_t)1
 
 /*
  * Remote symlink format and access functions.
  */
 #define XFS_SYMLINK_MAGIC   0x58534c4d  /* XSLM */
 
 struct xfs_dsymlink_hdr {
     __be32  sl_magic;
     __be32  sl_offset;
     __be32  sl_bytes;
     __be32  sl_crc;
     uuid_t  sl_uuid;
     __be64  sl_owner;
     __be64  sl_blkno;
     __be64  sl_lsn;
 };
 
 #define XFS_SYMLINK_CRC_OFF offsetof(struct xfs_dsymlink_hdr, sl_crc)
 
 #define XFS_SYMLINK_MAXLEN  1024
 /*
  * The maximum pathlen is 1024 bytes. Since the minimum file system
  * blocksize is 512 bytes, we can get a max of 3 extents back from
  * bmapi when crc headers are taken into account.
  */
 #define XFS_SYMLINK_MAPS 3
 
 #define XFS_SYMLINK_BUF_SPACE(mp, bufsize)  \
     ((bufsize) - (xfs_has_crc((mp)) ? \
             sizeof(struct xfs_dsymlink_hdr) : 0))
 
 
 /*
  * Allocation Btree format definitions
  *
  * There are two on-disk btrees, one sorted by blockno and one sorted
  * by blockcount and blockno.  All blocks look the same to make the code
  * simpler; if we have time later, we'll make the optimizations.
  */
 #define XFS_ABTB_MAGIC      0x41425442  /* 'ABTB' for bno tree */
 #define XFS_ABTB_CRC_MAGIC  0x41423342  /* 'AB3B' */
 #define XFS_ABTC_MAGIC      0x41425443  /* 'ABTC' for cnt tree */
 #define XFS_ABTC_CRC_MAGIC  0x41423343  /* 'AB3C' */
 
 /*
  * Data record/key structure
  */
 typedef struct xfs_alloc_rec {
     __be32      ar_startblock;  /* starting block number */
     __be32      ar_blockcount;  /* count of free blocks */
 } xfs_alloc_rec_t, xfs_alloc_key_t;
 
 typedef struct xfs_alloc_rec_incore {
     xfs_agblock_t   ar_startblock;  /* starting block number */
     xfs_extlen_t    ar_blockcount;  /* count of free blocks */
 } xfs_alloc_rec_incore_t;
 
 /* btree pointer type */
 typedef __be32 xfs_alloc_ptr_t;
 
 /*
  * Block numbers in the AG:
  * SB is sector 0, AGF is sector 1, AGI is sector 2, AGFL is sector 3.
  */
 #define XFS_BNO_BLOCK(mp)   ((xfs_agblock_t)(XFS_AGFL_BLOCK(mp) + 1))
 #define XFS_CNT_BLOCK(mp)   ((xfs_agblock_t)(XFS_BNO_BLOCK(mp) + 1))
 
 
 /*
  * Inode Allocation Btree format definitions
  *
  * There is a btree for the inode map per allocation group.
  */
 #define XFS_IBT_MAGIC       0x49414254  /* 'IABT' */
 #define XFS_IBT_CRC_MAGIC   0x49414233  /* 'IAB3' */
 #define XFS_FIBT_MAGIC      0x46494254  /* 'FIBT' */
 #define XFS_FIBT_CRC_MAGIC  0x46494233  /* 'FIB3' */
 
 typedef uint64_t    xfs_inofree_t;
 #define XFS_INODES_PER_CHUNK        (NBBY * sizeof(xfs_inofree_t))
 #define XFS_INODES_PER_CHUNK_LOG    (XFS_NBBYLOG + 3)
 #define XFS_INOBT_ALL_FREE      ((xfs_inofree_t)-1)
 #define XFS_INOBT_MASK(i)       ((xfs_inofree_t)1 << (i))
 
 #define XFS_INOBT_HOLEMASK_FULL     0   /* holemask for full chunk */
 #define XFS_INOBT_HOLEMASK_BITS     (NBBY * sizeof(uint16_t))
 #define XFS_INODES_PER_HOLEMASK_BIT \
     (XFS_INODES_PER_CHUNK / (NBBY * sizeof(uint16_t)))
 
 static inline xfs_inofree_t xfs_inobt_maskn(int i, int n)
 {
     return ((n >= XFS_INODES_PER_CHUNK ? 0 : XFS_INOBT_MASK(n)) - 1) << i;
 }
 
 /*
  * The on-disk inode record structure has two formats. The original "full"
  * format uses a 4-byte freecount. The "sparse" format uses a 1-byte freecount
  * and replaces the 3 high-order freecount bytes wth the holemask and inode
  * count.
  *
  * The holemask of the sparse record format allows an inode chunk to have holes
  * that refer to blocks not owned by the inode record. This facilitates inode
  * allocation in the event of severe free space fragmentation.
  */
 typedef struct xfs_inobt_rec {
     __be32      ir_startino;    /* starting inode number */
     union {
         struct {
             __be32  ir_freecount;   /* count of free inodes */
         } f;
         struct {
             __be16  ir_holemask;/* hole mask for sparse chunks */
             __u8    ir_count;   /* total inode count */
             __u8    ir_freecount;   /* count of free inodes */
         } sp;
     } ir_u;
     __be64      ir_free;    /* free inode mask */
 } xfs_inobt_rec_t;
 
 typedef struct xfs_inobt_rec_incore {
     xfs_agino_t ir_startino;    /* starting inode number */
     uint16_t    ir_holemask;    /* hole mask for sparse chunks */
     uint8_t     ir_count;   /* total inode count */
     uint8_t     ir_freecount;   /* count of free inodes (set bits) */
     xfs_inofree_t   ir_free;    /* free inode mask */
 } xfs_inobt_rec_incore_t;
 
 static inline bool xfs_inobt_issparse(uint16_t holemask)
 {
     /* non-zero holemask represents a sparse rec. */
     return holemask;
 }
 
 /*
  * Key structure
  */
 typedef struct xfs_inobt_key {
     __be32      ir_startino;    /* starting inode number */
 } xfs_inobt_key_t;
 
 /* btree pointer type */
 typedef __be32 xfs_inobt_ptr_t;
 
 /*
  * block numbers in the AG.
  */
 #define XFS_IBT_BLOCK(mp)       ((xfs_agblock_t)(XFS_CNT_BLOCK(mp) + 1))
 #define XFS_FIBT_BLOCK(mp)      ((xfs_agblock_t)(XFS_IBT_BLOCK(mp) + 1))
 
 /*
  * Reverse mapping btree format definitions
  *
  * There is a btree for the reverse map per allocation group
  */
 #define XFS_RMAP_CRC_MAGIC  0x524d4233  /* 'RMB3' */
 
 /*
  * Ownership info for an extent.  This is used to create reverse-mapping
  * entries.
  */
 #define XFS_OWNER_INFO_ATTR_FORK    (1 << 0)
 #define XFS_OWNER_INFO_BMBT_BLOCK   (1 << 1)
 struct xfs_owner_info {
     uint64_t        oi_owner;
     xfs_fileoff_t       oi_offset;
     unsigned int        oi_flags;
 };
 
 /*
  * Special owner types.
  *
  * Seeing as we only support up to 8EB, we have the upper bit of the owner field
  * to tell us we have a special owner value. We use these for static metadata
  * allocated at mkfs/growfs time, as well as for freespace management metadata.
  */
 #define XFS_RMAP_OWN_NULL   (-1ULL) /* No owner, for growfs */
 #define XFS_RMAP_OWN_UNKNOWN    (-2ULL) /* Unknown owner, for EFI recovery */
 #define XFS_RMAP_OWN_FS     (-3ULL) /* static fs metadata */
 #define XFS_RMAP_OWN_LOG    (-4ULL) /* static fs metadata */
 #define XFS_RMAP_OWN_AG     (-5ULL) /* AG freespace btree blocks */
 #define XFS_RMAP_OWN_INOBT  (-6ULL) /* Inode btree blocks */
 #define XFS_RMAP_OWN_INODES (-7ULL) /* Inode chunk */
 #define XFS_RMAP_OWN_REFC   (-8ULL) /* refcount tree */
 #define XFS_RMAP_OWN_COW    (-9ULL) /* cow allocations */
 #define XFS_RMAP_OWN_MIN    (-10ULL) /* guard */
 
 #define XFS_RMAP_NON_INODE_OWNER(owner) (!!((owner) & (1ULL << 63)))
 
 /*
  * Data record structure
  */
 struct xfs_rmap_rec {
     __be32      rm_startblock;  /* extent start block */
     __be32      rm_blockcount;  /* extent length */
     __be64      rm_owner;   /* extent owner */
     __be64      rm_offset;  /* offset within the owner */
 };
 
 /*
  * rmap btree record
  *  rm_offset:63 is the attribute fork flag
  *  rm_offset:62 is the bmbt block flag
  *  rm_offset:61 is the unwritten extent flag (same as l0:63 in bmbt)
  *  rm_offset:54-60 aren't used and should be zero
  *  rm_offset:0-53 is the block offset within the inode
  */
 #define XFS_RMAP_OFF_ATTR_FORK  ((uint64_t)1ULL << 63)
 #define XFS_RMAP_OFF_BMBT_BLOCK ((uint64_t)1ULL << 62)
 #define XFS_RMAP_OFF_UNWRITTEN  ((uint64_t)1ULL << 61)
 
 #define XFS_RMAP_LEN_MAX    ((uint32_t)~0U)
 #define XFS_RMAP_OFF_FLAGS  (XFS_RMAP_OFF_ATTR_FORK | \
                  XFS_RMAP_OFF_BMBT_BLOCK | \
                  XFS_RMAP_OFF_UNWRITTEN)
 #define XFS_RMAP_OFF_MASK   ((uint64_t)0x3FFFFFFFFFFFFFULL)
 
 #define XFS_RMAP_OFF(off)       ((off) & XFS_RMAP_OFF_MASK)
 
 #define XFS_RMAP_IS_BMBT_BLOCK(off) (!!((off) & XFS_RMAP_OFF_BMBT_BLOCK))
 #define XFS_RMAP_IS_ATTR_FORK(off)  (!!((off) & XFS_RMAP_OFF_ATTR_FORK))
 #define XFS_RMAP_IS_UNWRITTEN(len)  (!!((off) & XFS_RMAP_OFF_UNWRITTEN))
 
 #define RMAPBT_STARTBLOCK_BITLEN    32
 #define RMAPBT_BLOCKCOUNT_BITLEN    32
 #define RMAPBT_OWNER_BITLEN     64
 #define RMAPBT_ATTRFLAG_BITLEN      1
 #define RMAPBT_BMBTFLAG_BITLEN      1
 #define RMAPBT_EXNTFLAG_BITLEN      1
 #define RMAPBT_UNUSED_OFFSET_BITLEN 7
 #define RMAPBT_OFFSET_BITLEN        54
 
 #define XFS_RMAP_ATTR_FORK      (1 << 0)
 #define XFS_RMAP_BMBT_BLOCK     (1 << 1)
 #define XFS_RMAP_UNWRITTEN      (1 << 2)
 #define XFS_RMAP_KEY_FLAGS      (XFS_RMAP_ATTR_FORK | \
                      XFS_RMAP_BMBT_BLOCK)
 #define XFS_RMAP_REC_FLAGS      (XFS_RMAP_UNWRITTEN)
 struct xfs_rmap_irec {
     xfs_agblock_t   rm_startblock;  /* extent start block */
     xfs_extlen_t    rm_blockcount;  /* extent length */
     uint64_t    rm_owner;   /* extent owner */
     uint64_t    rm_offset;  /* offset within the owner */
     unsigned int    rm_flags;   /* state flags */
 };
 
 /*
  * Key structure
  *
  * We don't use the length for lookups
  */
 struct xfs_rmap_key {
     __be32      rm_startblock;  /* extent start block */
     __be64      rm_owner;   /* extent owner */
     __be64      rm_offset;  /* offset within the owner */
 } __attribute__((packed));
 
 /* btree pointer type */
 typedef __be32 xfs_rmap_ptr_t;
 
 #define XFS_RMAP_BLOCK(mp) \
     (xfs_has_finobt(((mp))) ? \
      XFS_FIBT_BLOCK(mp) + 1 : \
      XFS_IBT_BLOCK(mp) + 1)
 
 /*
  * Reference Count Btree format definitions
  *
  */
 #define XFS_REFC_CRC_MAGIC  0x52334643  /* 'R3FC' */
 
 unsigned int xfs_refc_block(struct xfs_mount *mp);
 
 /*
  * Data record/key structure
  *
  * Each record associates a range of physical blocks (starting at
  * rc_startblock and ending rc_blockcount blocks later) with a reference
  * count (rc_refcount).  Extents that are being used to stage a copy on
  * write (CoW) operation are recorded in the refcount btree with a
  * refcount of 1.  All other records must have a refcount > 1 and must
  * track an extent mapped only by file data forks.
  *
  * Extents with a single owner (attributes, metadata, non-shared file
  * data) are not tracked here.  Free space is also not tracked here.
  * This is consistent with pre-reflink XFS.
  */
 
 /*
  * Extents that are being used to stage a copy on write are stored
  * in the refcount btree with a refcount of 1 and the upper bit set
  * on the startblock.  This speeds up mount time deletion of stale
  * staging extents because they're all at the right side of the tree.
  */
 #define XFS_REFC_COW_START      ((xfs_agblock_t)(1U << 31))
 #define REFCNTBT_COWFLAG_BITLEN     1
 #define REFCNTBT_AGBLOCK_BITLEN     31
 
 struct xfs_refcount_rec {
     __be32      rc_startblock;  /* starting block number */
     __be32      rc_blockcount;  /* count of blocks */
     __be32      rc_refcount;    /* number of inodes linked here */
 };
 
 struct xfs_refcount_key {
     __be32      rc_startblock;  /* starting block number */
 };
 
 struct xfs_refcount_irec {
     xfs_agblock_t   rc_startblock;  /* starting block number */
     xfs_extlen_t    rc_blockcount;  /* count of free blocks */
     xfs_nlink_t rc_refcount;    /* number of inodes linked here */
 };
 
 #define MAXREFCOUNT ((xfs_nlink_t)~0U)
 #define MAXREFCEXTLEN   ((xfs_extlen_t)~0U)
 
 /* btree pointer type */
 typedef __be32 xfs_refcount_ptr_t;
 
 
 /*
  * BMAP Btree format definitions
  *
  * This includes both the root block definition that sits inside an inode fork
  * and the record/pointer formats for the leaf/node in the blocks.
  */
 #define XFS_BMAP_MAGIC      0x424d4150  /* 'BMAP' */
 #define XFS_BMAP_CRC_MAGIC  0x424d4133  /* 'BMA3' */
 
 /*
  * Bmap root header, on-disk form only.
  */
 typedef struct xfs_bmdr_block {
     __be16      bb_level;   /* 0 is a leaf */
     __be16      bb_numrecs; /* current # of data records */
 } xfs_bmdr_block_t;
 
 /*
  * Bmap btree record and extent descriptor.
  *  l0:63 is an extent flag (value 1 indicates non-normal).
  *  l0:9-62 are startoff.
  *  l0:0-8 and l1:21-63 are startblock.
  *  l1:0-20 are blockcount.
  */
 #define BMBT_EXNTFLAG_BITLEN    1
 #define BMBT_STARTOFF_BITLEN    54
 #define BMBT_STARTBLOCK_BITLEN  52
 #define BMBT_BLOCKCOUNT_BITLEN  21
 
 #define BMBT_STARTOFF_MASK  ((1ULL << BMBT_STARTOFF_BITLEN) - 1)
 #define BMBT_BLOCKCOUNT_MASK    ((1ULL << BMBT_BLOCKCOUNT_BITLEN) - 1)
 
 #define XFS_MAX_BMBT_EXTLEN ((xfs_extlen_t)(BMBT_BLOCKCOUNT_MASK))
 
 /*
  * bmbt records have a file offset (block) field that is 54 bits wide, so this
  * is the largest xfs_fileoff_t that we ever expect to see.
  */
 #define XFS_MAX_FILEOFF     (BMBT_STARTOFF_MASK + BMBT_BLOCKCOUNT_MASK)
 
 typedef struct xfs_bmbt_rec {
     __be64          l0, l1;
 } xfs_bmbt_rec_t;
 
 typedef uint64_t    xfs_bmbt_rec_base_t;    /* use this for casts */
 typedef xfs_bmbt_rec_t xfs_bmdr_rec_t;
 
 /*
  * Values and macros for delayed-allocation startblock fields.
  */
 #define STARTBLOCKVALBITS   17
 #define STARTBLOCKMASKBITS  (15 + 20)
 #define STARTBLOCKMASK      \
     (((((xfs_fsblock_t)1) << STARTBLOCKMASKBITS) - 1) << STARTBLOCKVALBITS)
 
 static inline int isnullstartblock(xfs_fsblock_t x)
 {
     return ((x) & STARTBLOCKMASK) == STARTBLOCKMASK;
 }
 
 static inline xfs_fsblock_t nullstartblock(int k)
 {
     ASSERT(k < (1 << STARTBLOCKVALBITS));
     return STARTBLOCKMASK | (k);
 }
 
 static inline xfs_filblks_t startblockval(xfs_fsblock_t x)
 {
     return (xfs_filblks_t)((x) & ~STARTBLOCKMASK);
 }
 
 /*
  * Key structure for non-leaf levels of the tree.
  */
 typedef struct xfs_bmbt_key {
     __be64      br_startoff;    /* starting file offset */
 } xfs_bmbt_key_t, xfs_bmdr_key_t;
 
 /* btree pointer type */
 typedef __be64 xfs_bmbt_ptr_t, xfs_bmdr_ptr_t;
 
 
 /*
  * Generic Btree block format definitions
  *
  * This is a combination of the actual format used on disk for short and long
  * format btrees.  The first three fields are shared by both format, but the
  * pointers are different and should be used with care.
  *
  * To get the size of the actual short or long form headers please use the size
  * macros below.  Never use sizeof(xfs_btree_block).
  *
  * The blkno, crc, lsn, owner and uuid fields are only available in filesystems
  * with the crc feature bit, and all accesses to them must be conditional on
  * that flag.
  */
 /* short form block header */
 struct xfs_btree_block_shdr {
     __be32      bb_leftsib;
     __be32      bb_rightsib;
 
     __be64      bb_blkno;
     __be64      bb_lsn;
     uuid_t      bb_uuid;
     __be32      bb_owner;
     __le32      bb_crc;
 };
 
 /* long form block header */
 struct xfs_btree_block_lhdr {
     __be64      bb_leftsib;
     __be64      bb_rightsib;
 
     __be64      bb_blkno;
     __be64      bb_lsn;
     uuid_t      bb_uuid;
     __be64      bb_owner;
     __le32      bb_crc;
     __be32      bb_pad; /* padding for alignment */
 };
 
 struct xfs_btree_block {
     __be32      bb_magic;   /* magic number for block type */
     __be16      bb_level;   /* 0 is a leaf */
     __be16      bb_numrecs; /* current # of data records */
     union {
         struct xfs_btree_block_shdr s;
         struct xfs_btree_block_lhdr l;
     } bb_u;             /* rest */
 };
 
 /* size of a short form block */
 #define XFS_BTREE_SBLOCK_LEN \
     (offsetof(struct xfs_btree_block, bb_u) + \
      offsetof(struct xfs_btree_block_shdr, bb_blkno))
 /* size of a long form block */
 #define XFS_BTREE_LBLOCK_LEN \
     (offsetof(struct xfs_btree_block, bb_u) + \
      offsetof(struct xfs_btree_block_lhdr, bb_blkno))
 
 /* sizes of CRC enabled btree blocks */
 #define XFS_BTREE_SBLOCK_CRC_LEN \
     (offsetof(struct xfs_btree_block, bb_u) + \
      sizeof(struct xfs_btree_block_shdr))
 #define XFS_BTREE_LBLOCK_CRC_LEN \
     (offsetof(struct xfs_btree_block, bb_u) + \
      sizeof(struct xfs_btree_block_lhdr))
 
 #define XFS_BTREE_SBLOCK_CRC_OFF \
     offsetof(struct xfs_btree_block, bb_u.s.bb_crc)
 #define XFS_BTREE_LBLOCK_CRC_OFF \
     offsetof(struct xfs_btree_block, bb_u.l.bb_crc)
 
 /*
  * On-disk XFS access control list structure.
  */
 struct xfs_acl_entry {
     __be32  ae_tag;
     __be32  ae_id;
     __be16  ae_perm;
     __be16  ae_pad;     /* fill the implicit hole in the structure */
 };
 
 struct xfs_acl {
     __be32          acl_cnt;
     struct xfs_acl_entry    acl_entry[];
 };
 
 /*
  * The number of ACL entries allowed is defined by the on-disk format.
  * For v4 superblocks, that is limited to 25 entries. For v5 superblocks, it is
  * limited only by the maximum size of the xattr that stores the information.
  */
 #define XFS_ACL_MAX_ENTRIES(mp) \
     (xfs_has_crc(mp) \
         ?  (XFS_XATTR_SIZE_MAX - sizeof(struct xfs_acl)) / \
                         sizeof(struct xfs_acl_entry) \
         : 25)
 
 #define XFS_ACL_SIZE(cnt) \
     (sizeof(struct xfs_acl) + \
         sizeof(struct xfs_acl_entry) * cnt)
 
 #define XFS_ACL_MAX_SIZE(mp) \
     XFS_ACL_SIZE(XFS_ACL_MAX_ENTRIES((mp)))
 
 
 /* On-disk XFS extended attribute names */
 #define SGI_ACL_FILE        "SGI_ACL_FILE"
 #define SGI_ACL_DEFAULT     "SGI_ACL_DEFAULT"
 #define SGI_ACL_FILE_SIZE   (sizeof(SGI_ACL_FILE)-1)
 #define SGI_ACL_DEFAULT_SIZE    (sizeof(SGI_ACL_DEFAULT)-1)
 
 #endif /* __XFS_FORMAT_H__ */

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