Merge branch 'master' into next

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / ocfs2 / ocfs2_fs.h

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * ocfs2_fs.h
 *
 * On-disk structures for OCFS2.
 *
 * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License, version 2,  as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#ifndef _OCFS2_FS_H
#define _OCFS2_FS_H

/* Version */
#define OCFS2_MAJOR_REV_LEVEL           0
#define OCFS2_MINOR_REV_LEVEL           90

/*
 * An OCFS2 volume starts this way:
 * Sector 0: Valid ocfs1_vol_disk_hdr that cleanly fails to mount OCFS.
 * Sector 1: Valid ocfs1_vol_label that cleanly fails to mount OCFS.
 * Block OCFS2_SUPER_BLOCK_BLKNO: OCFS2 superblock.
 *
 * All other structures are found from the superblock information.
 *
 * OCFS2_SUPER_BLOCK_BLKNO is in blocks, not sectors.  eg, for a
 * blocksize of 2K, it is 4096 bytes into disk.
 */
#define OCFS2_SUPER_BLOCK_BLKNO         2

/*
 * Cluster size limits. The maximum is kept arbitrarily at 1 MB, and could
 * grow if needed.
 */
#define OCFS2_MIN_CLUSTERSIZE           4096
#define OCFS2_MAX_CLUSTERSIZE           1048576

/*
 * Blocks cannot be bigger than clusters, so the maximum blocksize is the
 * minimum cluster size.
 */
#define OCFS2_MIN_BLOCKSIZE             512
#define OCFS2_MAX_BLOCKSIZE             OCFS2_MIN_CLUSTERSIZE

/* Filesystem magic number */
#define OCFS2_SUPER_MAGIC               0x7461636f

/* Object signatures */
#define OCFS2_SUPER_BLOCK_SIGNATURE     "OCFSV2"
#define OCFS2_INODE_SIGNATURE           "INODE01"
#define OCFS2_EXTENT_BLOCK_SIGNATURE    "EXBLK01"
#define OCFS2_GROUP_DESC_SIGNATURE      "GROUP01"
#define OCFS2_XATTR_BLOCK_SIGNATURE     "XATTR01"
#define OCFS2_DIR_TRAILER_SIGNATURE     "DIRTRL1"
#define OCFS2_DX_ROOT_SIGNATURE         "DXDIR01"
#define OCFS2_DX_LEAF_SIGNATURE         "DXLEAF1"
#define OCFS2_REFCOUNT_BLOCK_SIGNATURE  "REFCNT1"

/* Compatibility flags */
#define OCFS2_HAS_COMPAT_FEATURE(sb,mask)                       \
        ( OCFS2_SB(sb)->s_feature_compat & (mask) )
#define OCFS2_HAS_RO_COMPAT_FEATURE(sb,mask)                    \
        ( OCFS2_SB(sb)->s_feature_ro_compat & (mask) )
#define OCFS2_HAS_INCOMPAT_FEATURE(sb,mask)                     \
        ( OCFS2_SB(sb)->s_feature_incompat & (mask) )
#define OCFS2_SET_COMPAT_FEATURE(sb,mask)                       \
        OCFS2_SB(sb)->s_feature_compat |= (mask)
#define OCFS2_SET_RO_COMPAT_FEATURE(sb,mask)                    \
        OCFS2_SB(sb)->s_feature_ro_compat |= (mask)
#define OCFS2_SET_INCOMPAT_FEATURE(sb,mask)                     \
        OCFS2_SB(sb)->s_feature_incompat |= (mask)
#define OCFS2_CLEAR_COMPAT_FEATURE(sb,mask)                     \
        OCFS2_SB(sb)->s_feature_compat &= ~(mask)
#define OCFS2_CLEAR_RO_COMPAT_FEATURE(sb,mask)                  \
        OCFS2_SB(sb)->s_feature_ro_compat &= ~(mask)
#define OCFS2_CLEAR_INCOMPAT_FEATURE(sb,mask)                   \
        OCFS2_SB(sb)->s_feature_incompat &= ~(mask)

#define OCFS2_FEATURE_COMPAT_SUPP       (OCFS2_FEATURE_COMPAT_BACKUP_SB \
                                         | OCFS2_FEATURE_COMPAT_JBD2_SB)
#define OCFS2_FEATURE_INCOMPAT_SUPP     (OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT \
                                         | OCFS2_FEATURE_INCOMPAT_SPARSE_ALLOC \
                                         | OCFS2_FEATURE_INCOMPAT_INLINE_DATA \
                                         | OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP \
                                         | OCFS2_FEATURE_INCOMPAT_USERSPACE_STACK \
                                         | OCFS2_FEATURE_INCOMPAT_XATTR \
                                         | OCFS2_FEATURE_INCOMPAT_META_ECC \
                                         | OCFS2_FEATURE_INCOMPAT_INDEXED_DIRS \
                                         | OCFS2_FEATURE_INCOMPAT_REFCOUNT_TREE \
                                         | OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG  \
                                         | OCFS2_FEATURE_INCOMPAT_CLUSTERINFO)
#define OCFS2_FEATURE_RO_COMPAT_SUPP    (OCFS2_FEATURE_RO_COMPAT_UNWRITTEN \
                                         | OCFS2_FEATURE_RO_COMPAT_USRQUOTA \
                                         | OCFS2_FEATURE_RO_COMPAT_GRPQUOTA)

/*
 * Heartbeat-only devices are missing journals and other files.  The
 * filesystem driver can't load them, but the library can.  Never put
 * this in OCFS2_FEATURE_INCOMPAT_SUPP, *ever*.
 */
#define OCFS2_FEATURE_INCOMPAT_HEARTBEAT_DEV    0x0002

/*
 * tunefs sets this incompat flag before starting the resize and clears it
 * at the end. This flag protects users from inadvertently mounting the fs
 * after an aborted run without fsck-ing.
 */
#define OCFS2_FEATURE_INCOMPAT_RESIZE_INPROG    0x0004

/* Used to denote a non-clustered volume */
#define OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT      0x0008

/* Support for sparse allocation in b-trees */
#define OCFS2_FEATURE_INCOMPAT_SPARSE_ALLOC     0x0010

/*
 * Tunefs sets this incompat flag before starting an operation which
 * would require cleanup on abort. This is done to protect users from
 * inadvertently mounting the fs after an aborted run without
 * fsck-ing.
 *
 * s_tunefs_flags on the super block describes precisely which
 * operations were in progress.
 */
#define OCFS2_FEATURE_INCOMPAT_TUNEFS_INPROG    0x0020

/* Support for data packed into inode blocks */
#define OCFS2_FEATURE_INCOMPAT_INLINE_DATA      0x0040

/*
 * Support for alternate, userspace cluster stacks.  If set, the superblock
 * field s_cluster_info contains a tag for the alternate stack in use as
 * well as the name of the cluster being joined.
 * mount.ocfs2 must pass in a matching stack name.
 *
 * If not set, the classic stack will be used.  This is compatbile with
 * all older versions.
 */
#define OCFS2_FEATURE_INCOMPAT_USERSPACE_STACK  0x0080

/* Support for the extended slot map */
#define OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP 0x100

/* Support for extended attributes */
#define OCFS2_FEATURE_INCOMPAT_XATTR            0x0200

/* Support for indexed directores */
#define OCFS2_FEATURE_INCOMPAT_INDEXED_DIRS     0x0400

/* Metadata checksum and error correction */
#define OCFS2_FEATURE_INCOMPAT_META_ECC         0x0800

/* Refcount tree support */
#define OCFS2_FEATURE_INCOMPAT_REFCOUNT_TREE    0x1000

/* Discontigous block groups */
#define OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG     0x2000

/*
 * Incompat bit to indicate useable clusterinfo with stackflags for all
 * cluster stacks (userspace adnd o2cb). If this bit is set,
 * INCOMPAT_USERSPACE_STACK becomes superfluous and thus should not be set.
 */
#define OCFS2_FEATURE_INCOMPAT_CLUSTERINFO      0x4000

/*
 * backup superblock flag is used to indicate that this volume
 * has backup superblocks.
 */
#define OCFS2_FEATURE_COMPAT_BACKUP_SB          0x0001

/*
 * The filesystem will correctly handle journal feature bits.
 */
#define OCFS2_FEATURE_COMPAT_JBD2_SB            0x0002

/*
 * Unwritten extents support.
 */
#define OCFS2_FEATURE_RO_COMPAT_UNWRITTEN       0x0001

/*
 * Maintain quota information for this filesystem
 */
#define OCFS2_FEATURE_RO_COMPAT_USRQUOTA        0x0002
#define OCFS2_FEATURE_RO_COMPAT_GRPQUOTA        0x0004

/* The byte offset of the first backup block will be 1G.
 * The following will be 4G, 16G, 64G, 256G and 1T.
 */
#define OCFS2_BACKUP_SB_START                   1 << 30

/* the max backup superblock nums */
#define OCFS2_MAX_BACKUP_SUPERBLOCKS    6

/*
 * Flags on ocfs2_super_block.s_tunefs_flags
 */
#define OCFS2_TUNEFS_INPROG_REMOVE_SLOT         0x0001  /* Removing slots */

/*
 * Flags on ocfs2_dinode.i_flags
 */
#define OCFS2_VALID_FL          (0x00000001)    /* Inode is valid */
#define OCFS2_UNUSED2_FL        (0x00000002)
#define OCFS2_ORPHANED_FL       (0x00000004)    /* On the orphan list */
#define OCFS2_UNUSED3_FL        (0x00000008)
/* System inode flags */
#define OCFS2_SYSTEM_FL         (0x00000010)    /* System inode */
#define OCFS2_SUPER_BLOCK_FL    (0x00000020)    /* Super block */
#define OCFS2_LOCAL_ALLOC_FL    (0x00000040)    /* Slot local alloc bitmap */
#define OCFS2_BITMAP_FL         (0x00000080)    /* Allocation bitmap */
#define OCFS2_JOURNAL_FL        (0x00000100)    /* Slot local journal */
#define OCFS2_HEARTBEAT_FL      (0x00000200)    /* Heartbeat area */
#define OCFS2_CHAIN_FL          (0x00000400)    /* Chain allocator */
#define OCFS2_DEALLOC_FL        (0x00000800)    /* Truncate log */
#define OCFS2_QUOTA_FL          (0x00001000)    /* Quota file */

/*
 * Flags on ocfs2_dinode.i_dyn_features
 *
 * These can change much more often than i_flags. When adding flags,
 * keep in mind that i_dyn_features is only 16 bits wide.
 */
#define OCFS2_INLINE_DATA_FL    (0x0001)        /* Data stored in inode block */
#define OCFS2_HAS_XATTR_FL      (0x0002)
#define OCFS2_INLINE_XATTR_FL   (0x0004)
#define OCFS2_INDEXED_DIR_FL    (0x0008)
#define OCFS2_HAS_REFCOUNT_FL   (0x0010)

/* Inode attributes, keep in sync with EXT2 */
#define OCFS2_SECRM_FL                  FS_SECRM_FL     /* Secure deletion */
#define OCFS2_UNRM_FL                   FS_UNRM_FL      /* Undelete */
#define OCFS2_COMPR_FL                  FS_COMPR_FL     /* Compress file */
#define OCFS2_SYNC_FL                   FS_SYNC_FL      /* Synchronous updates */
#define OCFS2_IMMUTABLE_FL              FS_IMMUTABLE_FL /* Immutable file */
#define OCFS2_APPEND_FL                 FS_APPEND_FL    /* writes to file may only append */
#define OCFS2_NODUMP_FL                 FS_NODUMP_FL    /* do not dump file */
#define OCFS2_NOATIME_FL                FS_NOATIME_FL   /* do not update atime */
/* Reserved for compression usage... */
#define OCFS2_DIRTY_FL                  FS_DIRTY_FL
#define OCFS2_COMPRBLK_FL               FS_COMPRBLK_FL  /* One or more compressed clusters */
#define OCFS2_NOCOMP_FL                 FS_NOCOMP_FL    /* Don't compress */
#define OCFS2_ECOMPR_FL                 FS_ECOMPR_FL    /* Compression error */
/* End compression flags --- maybe not all used */
#define OCFS2_BTREE_FL                  FS_BTREE_FL     /* btree format dir */
#define OCFS2_INDEX_FL                  FS_INDEX_FL     /* hash-indexed directory */
#define OCFS2_IMAGIC_FL                 FS_IMAGIC_FL    /* AFS directory */
#define OCFS2_JOURNAL_DATA_FL           FS_JOURNAL_DATA_FL /* Reserved for ext3 */
#define OCFS2_NOTAIL_FL                 FS_NOTAIL_FL    /* file tail should not be merged */
#define OCFS2_DIRSYNC_FL                FS_DIRSYNC_FL   /* dirsync behaviour (directories only) */
#define OCFS2_TOPDIR_FL                 FS_TOPDIR_FL    /* Top of directory hierarchies*/
#define OCFS2_RESERVED_FL               FS_RESERVED_FL  /* reserved for ext2 lib */

#define OCFS2_FL_VISIBLE                FS_FL_USER_VISIBLE      /* User visible flags */
#define OCFS2_FL_MODIFIABLE             FS_FL_USER_MODIFIABLE   /* User modifiable flags */

/*
 * Extent record flags (e_node.leaf.flags)
 */
#define OCFS2_EXT_UNWRITTEN             (0x01)  /* Extent is allocated but
                                                 * unwritten */
#define OCFS2_EXT_REFCOUNTED            (0x02)  /* Extent is reference
                                                 * counted in an associated
                                                 * refcount tree */

/*
 * Journal Flags (ocfs2_dinode.id1.journal1.i_flags)
 */
#define OCFS2_JOURNAL_DIRTY_FL  (0x00000001)    /* Journal needs recovery */

/*
 * superblock s_state flags
 */
#define OCFS2_ERROR_FS          (0x00000001)    /* FS saw errors */

/* Limit of space in ocfs2_dir_entry */
#define OCFS2_MAX_FILENAME_LEN          255

/* Maximum slots on an ocfs2 file system */
#define OCFS2_MAX_SLOTS                 255

/* Slot map indicator for an empty slot */
#define OCFS2_INVALID_SLOT              -1

#define OCFS2_VOL_UUID_LEN              16
#define OCFS2_MAX_VOL_LABEL_LEN         64

/* The cluster stack fields */
#define OCFS2_STACK_LABEL_LEN           4
#define OCFS2_CLUSTER_NAME_LEN          16

/* Classic (historically speaking) cluster stack */
#define OCFS2_CLASSIC_CLUSTER_STACK     "o2cb"

/* Journal limits (in bytes) */
#define OCFS2_MIN_JOURNAL_SIZE          (4 * 1024 * 1024)

/*
 * Inline extended attribute size (in bytes)
 * The value chosen should be aligned to 16 byte boundaries.
 */
#define OCFS2_MIN_XATTR_INLINE_SIZE     256

/*
 * Cluster info flags (ocfs2_cluster_info.ci_stackflags)
 */
#define OCFS2_CLUSTER_O2CB_GLOBAL_HEARTBEAT     (0x01)

struct ocfs2_system_inode_info {
        char    *si_name;
        int     si_iflags;
        int     si_mode;
};

/* System file index */
enum {
        BAD_BLOCK_SYSTEM_INODE = 0,
        GLOBAL_INODE_ALLOC_SYSTEM_INODE,
        SLOT_MAP_SYSTEM_INODE,
#define OCFS2_FIRST_ONLINE_SYSTEM_INODE SLOT_MAP_SYSTEM_INODE
        HEARTBEAT_SYSTEM_INODE,
        GLOBAL_BITMAP_SYSTEM_INODE,
        USER_QUOTA_SYSTEM_INODE,
        GROUP_QUOTA_SYSTEM_INODE,
#define OCFS2_LAST_GLOBAL_SYSTEM_INODE GROUP_QUOTA_SYSTEM_INODE
#define OCFS2_FIRST_LOCAL_SYSTEM_INODE ORPHAN_DIR_SYSTEM_INODE
        ORPHAN_DIR_SYSTEM_INODE,
        EXTENT_ALLOC_SYSTEM_INODE,
        INODE_ALLOC_SYSTEM_INODE,
        JOURNAL_SYSTEM_INODE,
        LOCAL_ALLOC_SYSTEM_INODE,
        TRUNCATE_LOG_SYSTEM_INODE,
        LOCAL_USER_QUOTA_SYSTEM_INODE,
        LOCAL_GROUP_QUOTA_SYSTEM_INODE,
#define OCFS2_LAST_LOCAL_SYSTEM_INODE LOCAL_GROUP_QUOTA_SYSTEM_INODE
        NUM_SYSTEM_INODES
};
#define NUM_GLOBAL_SYSTEM_INODES OCFS2_FIRST_LOCAL_SYSTEM_INODE
#define NUM_LOCAL_SYSTEM_INODES \
                (NUM_SYSTEM_INODES - OCFS2_FIRST_LOCAL_SYSTEM_INODE)

static struct ocfs2_system_inode_info ocfs2_system_inodes[NUM_SYSTEM_INODES] = {
        /* Global system inodes (single copy) */
        /* The first two are only used from userspace mfks/tunefs */
        [BAD_BLOCK_SYSTEM_INODE]                = { "bad_blocks", 0, S_IFREG | 0644 },
        [GLOBAL_INODE_ALLOC_SYSTEM_INODE]       = { "global_inode_alloc", OCFS2_BITMAP_FL | OCFS2_CHAIN_FL, S_IFREG | 0644 },

        /* These are used by the running filesystem */
        [SLOT_MAP_SYSTEM_INODE]                 = { "slot_map", 0, S_IFREG | 0644 },
        [HEARTBEAT_SYSTEM_INODE]                = { "heartbeat", OCFS2_HEARTBEAT_FL, S_IFREG | 0644 },
        [GLOBAL_BITMAP_SYSTEM_INODE]            = { "global_bitmap", 0, S_IFREG | 0644 },
        [USER_QUOTA_SYSTEM_INODE]               = { "aquota.user", OCFS2_QUOTA_FL, S_IFREG | 0644 },
        [GROUP_QUOTA_SYSTEM_INODE]              = { "aquota.group", OCFS2_QUOTA_FL, S_IFREG | 0644 },

        /* Slot-specific system inodes (one copy per slot) */
        [ORPHAN_DIR_SYSTEM_INODE]               = { "orphan_dir:%04d", 0, S_IFDIR | 0755 },
        [EXTENT_ALLOC_SYSTEM_INODE]             = { "extent_alloc:%04d", OCFS2_BITMAP_FL | OCFS2_CHAIN_FL, S_IFREG | 0644 },
        [INODE_ALLOC_SYSTEM_INODE]              = { "inode_alloc:%04d", OCFS2_BITMAP_FL | OCFS2_CHAIN_FL, S_IFREG | 0644 },
        [JOURNAL_SYSTEM_INODE]                  = { "journal:%04d", OCFS2_JOURNAL_FL, S_IFREG | 0644 },
        [LOCAL_ALLOC_SYSTEM_INODE]              = { "local_alloc:%04d", OCFS2_BITMAP_FL | OCFS2_LOCAL_ALLOC_FL, S_IFREG | 0644 },
        [TRUNCATE_LOG_SYSTEM_INODE]             = { "truncate_log:%04d", OCFS2_DEALLOC_FL, S_IFREG | 0644 },
        [LOCAL_USER_QUOTA_SYSTEM_INODE]         = { "aquota.user:%04d", OCFS2_QUOTA_FL, S_IFREG | 0644 },
        [LOCAL_GROUP_QUOTA_SYSTEM_INODE]        = { "aquota.group:%04d", OCFS2_QUOTA_FL, S_IFREG | 0644 },
};

/* Parameter passed from mount.ocfs2 to module */
#define OCFS2_HB_NONE                   "heartbeat=none"
#define OCFS2_HB_LOCAL                  "heartbeat=local"
#define OCFS2_HB_GLOBAL                 "heartbeat=global"

/*
 * OCFS2 directory file types.  Only the low 3 bits are used.  The
 * other bits are reserved for now.
 */
#define OCFS2_FT_UNKNOWN        0
#define OCFS2_FT_REG_FILE       1
#define OCFS2_FT_DIR            2
#define OCFS2_FT_CHRDEV         3
#define OCFS2_FT_BLKDEV         4
#define OCFS2_FT_FIFO           5
#define OCFS2_FT_SOCK           6
#define OCFS2_FT_SYMLINK        7

#define OCFS2_FT_MAX            8

/*
 * OCFS2_DIR_PAD defines the directory entries boundaries
 *
 * NOTE: It must be a multiple of 4
 */
#define OCFS2_DIR_PAD                   4
#define OCFS2_DIR_ROUND                 (OCFS2_DIR_PAD - 1)
#define OCFS2_DIR_MEMBER_LEN            offsetof(struct ocfs2_dir_entry, name)
#define OCFS2_DIR_REC_LEN(name_len)     (((name_len) + OCFS2_DIR_MEMBER_LEN + \
                                          OCFS2_DIR_ROUND) & \
                                         ~OCFS2_DIR_ROUND)
#define OCFS2_DIR_MIN_REC_LEN   OCFS2_DIR_REC_LEN(1)

#define OCFS2_LINK_MAX          32000
#define OCFS2_DX_LINK_MAX       ((1U << 31) - 1U)
#define OCFS2_LINKS_HI_SHIFT    16
#define OCFS2_DX_ENTRIES_MAX    (0xffffffffU)

#define S_SHIFT                 12
static unsigned char ocfs2_type_by_mode[S_IFMT >> S_SHIFT] = {
        [S_IFREG >> S_SHIFT]  = OCFS2_FT_REG_FILE,
        [S_IFDIR >> S_SHIFT]  = OCFS2_FT_DIR,
        [S_IFCHR >> S_SHIFT]  = OCFS2_FT_CHRDEV,
        [S_IFBLK >> S_SHIFT]  = OCFS2_FT_BLKDEV,
        [S_IFIFO >> S_SHIFT]  = OCFS2_FT_FIFO,
        [S_IFSOCK >> S_SHIFT] = OCFS2_FT_SOCK,
        [S_IFLNK >> S_SHIFT]  = OCFS2_FT_SYMLINK,
};


/*
 * Convenience casts
 */
#define OCFS2_RAW_SB(dinode)            (&((dinode)->id2.i_super))

/*
 * Block checking structure.  This is used in metadata to validate the
 * contents.  If OCFS2_FEATURE_INCOMPAT_META_ECC is not set, it is all
 * zeros.
 */
struct ocfs2_block_check {
/*00*/  __le32 bc_crc32e;       /* 802.3 Ethernet II CRC32 */
        __le16 bc_ecc;          /* Single-error-correction parity vector.
                                   This is a simple Hamming code dependent
                                   on the blocksize.  OCFS2's maximum
                                   blocksize, 4K, requires 16 parity bits,
                                   so we fit in __le16. */
        __le16 bc_reserved1;
/*08*/
};

/*
 * On disk extent record for OCFS2
 * It describes a range of clusters on disk.
 *
 * Length fields are divided into interior and leaf node versions.
 * This leaves room for a flags field (OCFS2_EXT_*) in the leaf nodes.
 */
struct ocfs2_extent_rec {
/*00*/  __le32 e_cpos;          /* Offset into the file, in clusters */
        union {
                __le32 e_int_clusters; /* Clusters covered by all children */
                struct {
                        __le16 e_leaf_clusters; /* Clusters covered by this
                                                   extent */
                        __u8 e_reserved1;
                        __u8 e_flags; /* Extent flags */
                };
        };
        __le64 e_blkno;         /* Physical disk offset, in blocks */
/*10*/
};

struct ocfs2_chain_rec {
        __le32 c_free;  /* Number of free bits in this chain. */
        __le32 c_total; /* Number of total bits in this chain */
        __le64 c_blkno; /* Physical disk offset (blocks) of 1st group */
};

struct ocfs2_truncate_rec {
        __le32 t_start;         /* 1st cluster in this log */
        __le32 t_clusters;      /* Number of total clusters covered */
};

/*
 * On disk extent list for OCFS2 (node in the tree).  Note that this
 * is contained inside ocfs2_dinode or ocfs2_extent_block, so the
 * offsets are relative to ocfs2_dinode.id2.i_list or
 * ocfs2_extent_block.h_list, respectively.
 */
struct ocfs2_extent_list {
/*00*/  __le16 l_tree_depth;            /* Extent tree depth from this
                                           point.  0 means data extents
                                           hang directly off this
                                           header (a leaf)
                                           NOTE: The high 8 bits cannot be
                                           used - tree_depth is never that big.
                                        */
        __le16 l_count;                 /* Number of extent records */
        __le16 l_next_free_rec;         /* Next unused extent slot */
        __le16 l_reserved1;
        __le64 l_reserved2;             /* Pad to
                                           sizeof(ocfs2_extent_rec) */
/*10*/  struct ocfs2_extent_rec l_recs[0];      /* Extent records */
};

/*
 * On disk allocation chain list for OCFS2.  Note that this is
 * contained inside ocfs2_dinode, so the offsets are relative to
 * ocfs2_dinode.id2.i_chain.
 */
struct ocfs2_chain_list {
/*00*/  __le16 cl_cpg;                  /* Clusters per Block Group */
        __le16 cl_bpc;                  /* Bits per cluster */
        __le16 cl_count;                /* Total chains in this list */
        __le16 cl_next_free_rec;        /* Next unused chain slot */
        __le64 cl_reserved1;
/*10*/  struct ocfs2_chain_rec cl_recs[0];      /* Chain records */
};

/*
 * On disk deallocation log for OCFS2.  Note that this is
 * contained inside ocfs2_dinode, so the offsets are relative to
 * ocfs2_dinode.id2.i_dealloc.
 */
struct ocfs2_truncate_log {
/*00*/  __le16 tl_count;                /* Total records in this log */
        __le16 tl_used;                 /* Number of records in use */
        __le32 tl_reserved1;
/*08*/  struct ocfs2_truncate_rec tl_recs[0];   /* Truncate records */
};

/*
 * On disk extent block (indirect block) for OCFS2
 */
struct ocfs2_extent_block
{
/*00*/  __u8 h_signature[8];            /* Signature for verification */
        struct ocfs2_block_check h_check;       /* Error checking */
/*10*/  __le16 h_suballoc_slot;         /* Slot suballocator this
                                           extent_header belongs to */
        __le16 h_suballoc_bit;          /* Bit offset in suballocator
                                           block group */
        __le32 h_fs_generation;         /* Must match super block */
        __le64 h_blkno;                 /* Offset on disk, in blocks */
/*20*/  __le64 h_suballoc_loc;          /* Suballocator block group this
                                           eb belongs to.  Only valid
                                           if allocated from a
                                           discontiguous block group */
        __le64 h_next_leaf_blk;         /* Offset on disk, in blocks,
                                           of next leaf header pointing
                                           to data */
/*30*/  struct ocfs2_extent_list h_list;        /* Extent record list */
/* Actual on-disk size is one block */
};

/*
 * On disk slot map for OCFS2.  This defines the contents of the "slot_map"
 * system file.  A slot is valid if it contains a node number >= 0.  The
 * value -1 (0xFFFF) is OCFS2_INVALID_SLOT.  This marks a slot empty.
 */
struct ocfs2_slot_map {
/*00*/  __le16 sm_slots[0];
/*
 * Actual on-disk size is one block.  OCFS2_MAX_SLOTS is 255,
 * 255 * sizeof(__le16) == 512B, within the 512B block minimum blocksize.
 */
};

struct ocfs2_extended_slot {
/*00*/  __u8    es_valid;
        __u8    es_reserved1[3];
        __le32  es_node_num;
/*10*/
};

/*
 * The extended slot map, used when OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP
 * is set.  It separates out the valid marker from the node number, and
 * has room to grow.  Unlike the old slot map, this format is defined by
 * i_size.
 */
struct ocfs2_slot_map_extended {
/*00*/  struct ocfs2_extended_slot se_slots[0];
/*
 * Actual size is i_size of the slot_map system file.  It should
 * match s_max_slots * sizeof(struct ocfs2_extended_slot)
 */
};

/*
 * ci_stackflags is only valid if the incompat bit
 * OCFS2_FEATURE_INCOMPAT_CLUSTERINFO is set.
 */
struct ocfs2_cluster_info {
/*00*/  __u8   ci_stack[OCFS2_STACK_LABEL_LEN];
        union {
                __le32 ci_reserved;
                struct {
                        __u8 ci_stackflags;
                        __u8 ci_reserved1;
                        __u8 ci_reserved2;
                        __u8 ci_reserved3;
                };
        };
/*08*/  __u8   ci_cluster[OCFS2_CLUSTER_NAME_LEN];
/*18*/
};

/*
 * On disk superblock for OCFS2
 * Note that it is contained inside an ocfs2_dinode, so all offsets
 * are relative to the start of ocfs2_dinode.id2.
 */
struct ocfs2_super_block {
/*00*/  __le16 s_major_rev_level;
        __le16 s_minor_rev_level;
        __le16 s_mnt_count;
        __le16 s_max_mnt_count;
        __le16 s_state;                 /* File system state */
        __le16 s_errors;                        /* Behaviour when detecting errors */
        __le32 s_checkinterval;         /* Max time between checks */
/*10*/  __le64 s_lastcheck;             /* Time of last check */
        __le32 s_creator_os;            /* OS */
        __le32 s_feature_compat;                /* Compatible feature set */
/*20*/  __le32 s_feature_incompat;      /* Incompatible feature set */
        __le32 s_feature_ro_compat;     /* Readonly-compatible feature set */
        __le64 s_root_blkno;            /* Offset, in blocks, of root directory
                                           dinode */
/*30*/  __le64 s_system_dir_blkno;      /* Offset, in blocks, of system
                                           directory dinode */
        __le32 s_blocksize_bits;                /* Blocksize for this fs */
        __le32 s_clustersize_bits;      /* Clustersize for this fs */
/*40*/  __le16 s_max_slots;             /* Max number of simultaneous mounts
                                           before tunefs required */
        __le16 s_tunefs_flag;
        __le32 s_uuid_hash;             /* hash value of uuid */
        __le64 s_first_cluster_group;   /* Block offset of 1st cluster
                                         * group header */
/*50*/  __u8  s_label[OCFS2_MAX_VOL_LABEL_LEN]; /* Label for mounting, etc. */
/*90*/  __u8  s_uuid[OCFS2_VOL_UUID_LEN];       /* 128-bit uuid */
/*A0*/  struct ocfs2_cluster_info s_cluster_info; /* Only valid if either
                                                     userspace or clusterinfo
                                                     INCOMPAT flag set. */
/*B8*/  __le16 s_xattr_inline_size;     /* extended attribute inline size
                                           for this fs*/
        __le16 s_reserved0;
        __le32 s_dx_seed[3];            /* seed[0-2] for dx dir hash.
                                         * s_uuid_hash serves as seed[3]. */
/*C0*/  __le64 s_reserved2[15];         /* Fill out superblock */
/*140*/

        /*
         * NOTE: As stated above, all offsets are relative to
         * ocfs2_dinode.id2, which is at 0xC0 in the inode.
         * 0xC0 + 0x140 = 0x200 or 512 bytes.  A superblock must fit within
         * our smallest blocksize, which is 512 bytes.  To ensure this,
         * we reserve the space in s_reserved2.  Anything past s_reserved2
         * will not be available on the smallest blocksize.
         */
};

/*
 * Local allocation bitmap for OCFS2 slots
 * Note that it exists inside an ocfs2_dinode, so all offsets are
 * relative to the start of ocfs2_dinode.id2.
 */
struct ocfs2_local_alloc
{
/*00*/  __le32 la_bm_off;       /* Starting bit offset in main bitmap */
        __le16 la_size;         /* Size of included bitmap, in bytes */
        __le16 la_reserved1;
        __le64 la_reserved2;
/*10*/  __u8   la_bitmap[0];
};

/*
 * Data-in-inode header. This is only used if i_dyn_features has
 * OCFS2_INLINE_DATA_FL set.
 */
struct ocfs2_inline_data
{
/*00*/  __le16  id_count;       /* Number of bytes that can be used
                                 * for data, starting at id_data */
        __le16  id_reserved0;
        __le32  id_reserved1;
        __u8    id_data[0];     /* Start of user data */
};

/*
 * On disk inode for OCFS2
 */
struct ocfs2_dinode {
/*00*/  __u8 i_signature[8];            /* Signature for validation */
        __le32 i_generation;            /* Generation number */
        __le16 i_suballoc_slot;         /* Slot suballocator this inode
                                           belongs to */
        __le16 i_suballoc_bit;          /* Bit offset in suballocator
                                           block group */
/*10*/  __le16 i_links_count_hi;        /* High 16 bits of links count */
        __le16 i_xattr_inline_size;
        __le32 i_clusters;              /* Cluster count */
        __le32 i_uid;                   /* Owner UID */
        __le32 i_gid;                   /* Owning GID */
/*20*/  __le64 i_size;                  /* Size in bytes */
        __le16 i_mode;                  /* File mode */
        __le16 i_links_count;           /* Links count */
        __le32 i_flags;                 /* File flags */
/*30*/  __le64 i_atime;                 /* Access time */
        __le64 i_ctime;                 /* Creation time */
/*40*/  __le64 i_mtime;                 /* Modification time */
        __le64 i_dtime;                 /* Deletion time */
/*50*/  __le64 i_blkno;                 /* Offset on disk, in blocks */
        __le64 i_last_eb_blk;           /* Pointer to last extent
                                           block */
/*60*/  __le32 i_fs_generation;         /* Generation per fs-instance */
        __le32 i_atime_nsec;
        __le32 i_ctime_nsec;
        __le32 i_mtime_nsec;
/*70*/  __le32 i_attr;
        __le16 i_orphaned_slot;         /* Only valid when OCFS2_ORPHANED_FL
                                           was set in i_flags */
        __le16 i_dyn_features;
        __le64 i_xattr_loc;
/*80*/  struct ocfs2_block_check i_check;       /* Error checking */
/*88*/  __le64 i_dx_root;               /* Pointer to dir index root block */
/*90*/  __le64 i_refcount_loc;
        __le64 i_suballoc_loc;          /* Suballocator block group this
                                           inode belongs to.  Only valid
                                           if allocated from a
                                           discontiguous block group */
/*A0*/  __le64 i_reserved2[3];
/*B8*/  union {
                __le64 i_pad1;          /* Generic way to refer to this
                                           64bit union */
                struct {
                        __le64 i_rdev;  /* Device number */
                } dev1;
                struct {                /* Info for bitmap system
                                           inodes */
                        __le32 i_used;  /* Bits (ie, clusters) used  */
                        __le32 i_total; /* Total bits (clusters)
                                           available */
                } bitmap1;
                struct {                /* Info for journal system
                                           inodes */
                        __le32 ij_flags;        /* Mounted, version, etc. */
                        __le32 ij_recovery_generation; /* Incremented when the
                                                          journal is recovered
                                                          after an unclean
                                                          shutdown */
                } journal1;
        } id1;                          /* Inode type dependent 1 */
/*C0*/  union {
                struct ocfs2_super_block        i_super;
                struct ocfs2_local_alloc        i_lab;
                struct ocfs2_chain_list         i_chain;
                struct ocfs2_extent_list        i_list;
                struct ocfs2_truncate_log       i_dealloc;
                struct ocfs2_inline_data        i_data;
                __u8                            i_symlink[0];
        } id2;
/* Actual on-disk size is one block */
};

/*
 * On-disk directory entry structure for OCFS2
 *
 * Packed as this structure could be accessed unaligned on 64-bit platforms
 */
struct ocfs2_dir_entry {
/*00*/  __le64   inode;                  /* Inode number */
        __le16   rec_len;                /* Directory entry length */
        __u8    name_len;               /* Name length */
        __u8    file_type;
/*0C*/  char    name[OCFS2_MAX_FILENAME_LEN];   /* File name */
/* Actual on-disk length specified by rec_len */
} __attribute__ ((packed));

/*
 * Per-block record for the unindexed directory btree. This is carefully
 * crafted so that the rec_len and name_len records of an ocfs2_dir_entry are
 * mirrored. That way, the directory manipulation code needs a minimal amount
 * of update.
 *
 * NOTE: Keep this structure aligned to a multiple of 4 bytes.
 */
struct ocfs2_dir_block_trailer {
/*00*/  __le64          db_compat_inode;        /* Always zero. Was inode */

        __le16          db_compat_rec_len;      /* Backwards compatible with
                                                 * ocfs2_dir_entry. */
        __u8            db_compat_name_len;     /* Always zero. Was name_len */
        __u8            db_reserved0;
        __le16          db_reserved1;
        __le16          db_free_rec_len;        /* Size of largest empty hole
                                                 * in this block. (unused) */
/*10*/  __u8            db_signature[8];        /* Signature for verification */
        __le64          db_reserved2;
        __le64          db_free_next;           /* Next block in list (unused) */
/*20*/  __le64          db_blkno;               /* Offset on disk, in blocks */
        __le64          db_parent_dinode;       /* dinode which owns me, in
                                                   blocks */
/*30*/  struct ocfs2_block_check db_check;      /* Error checking */
/*40*/
};

 /*
 * A directory entry in the indexed tree. We don't store the full name here,
 * but instead provide a pointer to the full dirent in the unindexed tree.
 *
 * We also store name_len here so as to reduce the number of leaf blocks we
 * need to search in case of collisions.
 */
struct ocfs2_dx_entry {
        __le32          dx_major_hash;  /* Used to find logical
                                         * cluster in index */
        __le32          dx_minor_hash;  /* Lower bits used to find
                                         * block in cluster */
        __le64          dx_dirent_blk;  /* Physical block in unindexed
                                         * tree holding this dirent. */
};

struct ocfs2_dx_entry_list {
        __le32          de_reserved;
        __le16          de_count;       /* Maximum number of entries
                                         * possible in de_entries */
        __le16          de_num_used;    /* Current number of
                                         * de_entries entries */
        struct  ocfs2_dx_entry          de_entries[0];  /* Indexed dir entries
                                                         * in a packed array of
                                                         * length de_num_used */
};

#define OCFS2_DX_FLAG_INLINE    0x01

/*
 * A directory indexing block. Each indexed directory has one of these,
 * pointed to by ocfs2_dinode.
 *
 * This block stores an indexed btree root, and a set of free space
 * start-of-list pointers.
 */
struct ocfs2_dx_root_block {
        __u8            dr_signature[8];        /* Signature for verification */
        struct ocfs2_block_check dr_check;      /* Error checking */
        __le16          dr_suballoc_slot;       /* Slot suballocator this
                                                 * block belongs to. */
        __le16          dr_suballoc_bit;        /* Bit offset in suballocator
                                                 * block group */
        __le32          dr_fs_generation;       /* Must match super block */
        __le64          dr_blkno;               /* Offset on disk, in blocks */
        __le64          dr_last_eb_blk;         /* Pointer to last
                                                 * extent block */
        __le32          dr_clusters;            /* Clusters allocated
                                                 * to the indexed tree. */
        __u8            dr_flags;               /* OCFS2_DX_FLAG_* flags */
        __u8            dr_reserved0;
        __le16          dr_reserved1;
        __le64          dr_dir_blkno;           /* Pointer to parent inode */
        __le32          dr_num_entries;         /* Total number of
                                                 * names stored in
                                                 * this directory.*/
        __le32          dr_reserved2;
        __le64          dr_free_blk;            /* Pointer to head of free
                                                 * unindexed block list. */
        __le64          dr_suballoc_loc;        /* Suballocator block group
                                                   this root belongs to.
                                                   Only valid if allocated
                                                   from a discontiguous
                                                   block group */
        __le64          dr_reserved3[14];
        union {
                struct ocfs2_extent_list dr_list; /* Keep this aligned to 128
                                                   * bits for maximum space
                                                   * efficiency. */
                struct ocfs2_dx_entry_list dr_entries; /* In-root-block list of
                                                        * entries. We grow out
                                                        * to extents if this
                                                        * gets too big. */
        };
};

/*
 * The header of a leaf block in the indexed tree.
 */
struct ocfs2_dx_leaf {
        __u8            dl_signature[8];/* Signature for verification */
        struct ocfs2_block_check dl_check;      /* Error checking */
        __le64          dl_blkno;       /* Offset on disk, in blocks */
        __le32          dl_fs_generation;/* Must match super block */
        __le32          dl_reserved0;
        __le64          dl_reserved1;
        struct ocfs2_dx_entry_list      dl_list;
};

/*
 * Largest bitmap for a block (suballocator) group in bytes.  This limit
 * does not affect cluster groups (global allocator).  Cluster group
 * bitmaps run to the end of the block.
 */
#define OCFS2_MAX_BG_BITMAP_SIZE        256

/*
 * On disk allocator group structure for OCFS2
 */
struct ocfs2_group_desc
{
/*00*/  __u8    bg_signature[8];        /* Signature for validation */
        __le16   bg_size;                /* Size of included bitmap in
                                           bytes. */
        __le16   bg_bits;                /* Bits represented by this
                                           group. */
        __le16  bg_free_bits_count;     /* Free bits count */
        __le16   bg_chain;               /* What chain I am in. */
/*10*/  __le32   bg_generation;
        __le32  bg_reserved1;
        __le64   bg_next_group;          /* Next group in my list, in
                                           blocks */
/*20*/  __le64   bg_parent_dinode;       /* dinode which owns me, in
                                           blocks */
        __le64   bg_blkno;               /* Offset on disk, in blocks */
/*30*/  struct ocfs2_block_check bg_check;      /* Error checking */
        __le64   bg_reserved2;
/*40*/  union {
                __u8    bg_bitmap[0];
                struct {
                        /*
                         * Block groups may be discontiguous when
                         * OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG is set.
                         * The extents of a discontigous block group are
                         * stored in bg_list.  It is a flat list.
                         * l_tree_depth must always be zero.  A
                         * discontiguous group is signified by a non-zero
                         * bg_list->l_next_free_rec.  Only block groups
                         * can be discontiguous; Cluster groups cannot.
                         * We've never made a block group with more than
                         * 2048 blocks (256 bytes of bg_bitmap).  This
                         * codifies that limit so that we can fit bg_list.
                         * bg_size of a discontiguous block group will
                         * be 256 to match bg_bitmap_filler.
                         */
                        __u8 bg_bitmap_filler[OCFS2_MAX_BG_BITMAP_SIZE];
/*140*/                 struct ocfs2_extent_list bg_list;
                };
        };
/* Actual on-disk size is one block */
};

struct ocfs2_refcount_rec {
/*00*/  __le64 r_cpos;          /* Physical offset, in clusters */
        __le32 r_clusters;      /* Clusters covered by this extent */
        __le32 r_refcount;      /* Reference count of this extent */
/*10*/
};
#define OCFS2_32BIT_POS_MASK            (0xffffffffULL)

#define OCFS2_REFCOUNT_LEAF_FL          (0x00000001)
#define OCFS2_REFCOUNT_TREE_FL          (0x00000002)

struct ocfs2_refcount_list {
/*00*/  __le16 rl_count;        /* Maximum number of entries possible
                                   in rl_records */
        __le16 rl_used;         /* Current number of used records */
        __le32 rl_reserved2;
        __le64 rl_reserved1;    /* Pad to sizeof(ocfs2_refcount_record) */
/*10*/  struct ocfs2_refcount_rec rl_recs[0];   /* Refcount records */
};


struct ocfs2_refcount_block {
/*00*/  __u8 rf_signature[8];           /* Signature for verification */
        __le16 rf_suballoc_slot;        /* Slot suballocator this block
                                           belongs to */
        __le16 rf_suballoc_bit;         /* Bit offset in suballocator
                                           block group */
        __le32 rf_fs_generation;        /* Must match superblock */
/*10*/  __le64 rf_blkno;                /* Offset on disk, in blocks */
        __le64 rf_parent;               /* Parent block, only valid if
                                           OCFS2_REFCOUNT_LEAF_FL is set in
                                           rf_flags */
/*20*/  struct ocfs2_block_check rf_check;      /* Error checking */
        __le64 rf_last_eb_blk;          /* Pointer to last extent block */
/*30*/  __le32 rf_count;                /* Number of inodes sharing this
                                           refcount tree */
        __le32 rf_flags;                /* See the flags above */
        __le32 rf_clusters;             /* clusters covered by refcount tree. */
        __le32 rf_cpos;                 /* cluster offset in refcount tree.*/
/*40*/  __le32 rf_generation;           /* generation number. all be the same
                                         * for the same refcount tree. */
        __le32 rf_reserved0;
        __le64 rf_suballoc_loc;         /* Suballocator block group this
                                           refcount block belongs to. Only
                                           valid if allocated from a
                                           discontiguous block group */
/*50*/  __le64 rf_reserved1[6];
/*80*/  union {
                struct ocfs2_refcount_list rf_records;  /* List of refcount
                                                          records */
                struct ocfs2_extent_list rf_list;       /* Extent record list,
                                                        only valid if
                                                        OCFS2_REFCOUNT_TREE_FL
                                                        is set in rf_flags */
        };
/* Actual on-disk size is one block */
};

/*
 * On disk extended attribute structure for OCFS2.
 */

/*
 * ocfs2_xattr_entry indicates one extend attribute.
 *
 * Note that it can be stored in inode, one block or one xattr bucket.
 */
struct ocfs2_xattr_entry {
        __le32  xe_name_hash;    /* hash value of xattr prefix+suffix. */
        __le16  xe_name_offset;  /* byte offset from the 1st entry in the
                                    local xattr storage(inode, xattr block or
                                    xattr bucket). */
        __u8    xe_name_len;     /* xattr name len, doesn't include prefix. */
        __u8    xe_type;         /* the low 7 bits indicate the name prefix
                                  * type and the highest bit indicates whether
                                  * the EA is stored in the local storage. */
        __le64  xe_value_size;   /* real xattr value length. */
};

/*
 * On disk structure for xattr header.
 *
 * One ocfs2_xattr_header describes how many ocfs2_xattr_entry records in
 * the local xattr storage.
 */
struct ocfs2_xattr_header {
        __le16  xh_count;                       /* contains the count of how
                                                   many records are in the
                                                   local xattr storage. */
        __le16  xh_free_start;                  /* current offset for storing
                                                   xattr. */
        __le16  xh_name_value_len;              /* total length of name/value
                                                   length in this bucket. */
        __le16  xh_num_buckets;                 /* Number of xattr buckets
                                                   in this extent record,
                                                   only valid in the first
                                                   bucket. */
        struct ocfs2_block_check xh_check;      /* Error checking
                                                   (Note, this is only
                                                    used for xattr
                                                    buckets.  A block uses
                                                    xb_check and sets
                                                    this field to zero.) */
        struct ocfs2_xattr_entry xh_entries[0]; /* xattr entry list. */
};

/*
 * On disk structure for xattr value root.
 *
 * When an xattr's value is large enough, it is stored in an external
 * b-tree like file data.  The xattr value root points to this structure.
 */
struct ocfs2_xattr_value_root {
/*00*/  __le32  xr_clusters;              /* clusters covered by xattr value. */
        __le32  xr_reserved0;
        __le64  xr_last_eb_blk;           /* Pointer to last extent block */
/*10*/  struct ocfs2_extent_list xr_list; /* Extent record list */
};

/*
 * On disk structure for xattr tree root.
 *
 * It is used when there are too many extended attributes for one file. These
 * attributes will be organized and stored in an indexed-btree.
 */
struct ocfs2_xattr_tree_root {
/*00*/  __le32  xt_clusters;              /* clusters covered by xattr. */
        __le32  xt_reserved0;
        __le64  xt_last_eb_blk;           /* Pointer to last extent block */
/*10*/  struct ocfs2_extent_list xt_list; /* Extent record list */
};

#define OCFS2_XATTR_INDEXED     0x1
#define OCFS2_HASH_SHIFT        5
#define OCFS2_XATTR_ROUND       3
#define OCFS2_XATTR_SIZE(size)  (((size) + OCFS2_XATTR_ROUND) & \
                                ~(OCFS2_XATTR_ROUND))

#define OCFS2_XATTR_BUCKET_SIZE                 4096
#define OCFS2_XATTR_MAX_BLOCKS_PER_BUCKET       (OCFS2_XATTR_BUCKET_SIZE \
                                                 / OCFS2_MIN_BLOCKSIZE)

/*
 * On disk structure for xattr block.
 */
struct ocfs2_xattr_block {
/*00*/  __u8    xb_signature[8];     /* Signature for verification */
        __le16  xb_suballoc_slot;    /* Slot suballocator this
                                        block belongs to. */
        __le16  xb_suballoc_bit;     /* Bit offset in suballocator
                                        block group */
        __le32  xb_fs_generation;    /* Must match super block */
/*10*/  __le64  xb_blkno;            /* Offset on disk, in blocks */
        struct ocfs2_block_check xb_check;      /* Error checking */
/*20*/  __le16  xb_flags;            /* Indicates whether this block contains
                                        real xattr or a xattr tree. */
        __le16  xb_reserved0;
        __le32  xb_reserved1;
        __le64  xb_suballoc_loc;        /* Suballocator block group this
                                           xattr block belongs to. Only
                                           valid if allocated from a
                                           discontiguous block group */
/*30*/  union {
                struct ocfs2_xattr_header xb_header; /* xattr header if this
                                                        block contains xattr */
                struct ocfs2_xattr_tree_root xb_root;/* xattr tree root if this
                                                        block cotains xattr
                                                        tree. */
        } xb_attrs;
};

#define OCFS2_XATTR_ENTRY_LOCAL         0x80
#define OCFS2_XATTR_TYPE_MASK           0x7F
static inline void ocfs2_xattr_set_local(struct ocfs2_xattr_entry *xe,
                                         int local)
{
        if (local)
                xe->xe_type |= OCFS2_XATTR_ENTRY_LOCAL;
        else
                xe->xe_type &= ~OCFS2_XATTR_ENTRY_LOCAL;
}

static inline int ocfs2_xattr_is_local(struct ocfs2_xattr_entry *xe)
{
        return xe->xe_type & OCFS2_XATTR_ENTRY_LOCAL;
}

static inline void ocfs2_xattr_set_type(struct ocfs2_xattr_entry *xe, int type)
{
        xe->xe_type |= type & OCFS2_XATTR_TYPE_MASK;
}

static inline int ocfs2_xattr_get_type(struct ocfs2_xattr_entry *xe)
{
        return xe->xe_type & OCFS2_XATTR_TYPE_MASK;
}

/*
 *  On disk structures for global quota file
 */

/* Magic numbers and known versions for global quota files */
#define OCFS2_GLOBAL_QMAGICS {\
        0x0cf52470, /* USRQUOTA */ \
        0x0cf52471  /* GRPQUOTA */ \
}

#define OCFS2_GLOBAL_QVERSIONS {\
        0, \
        0, \
}


/* Each block of each quota file has a certain fixed number of bytes reserved
 * for OCFS2 internal use at its end. OCFS2 can use it for things like
 * checksums, etc. */
#define OCFS2_QBLK_RESERVED_SPACE 8

/* Generic header of all quota files */
struct ocfs2_disk_dqheader {
        __le32 dqh_magic;       /* Magic number identifying file */
        __le32 dqh_version;     /* Quota format version */
};

#define OCFS2_GLOBAL_INFO_OFF (sizeof(struct ocfs2_disk_dqheader))

/* Information header of global quota file (immediately follows the generic
 * header) */
struct ocfs2_global_disk_dqinfo {
/*00*/  __le32 dqi_bgrace;      /* Grace time for space softlimit excess */
        __le32 dqi_igrace;      /* Grace time for inode softlimit excess */
        __le32 dqi_syncms;      /* Time after which we sync local changes to
                                 * global quota file */
        __le32 dqi_blocks;      /* Number of blocks in quota file */
/*10*/  __le32 dqi_free_blk;    /* First free block in quota file */
        __le32 dqi_free_entry;  /* First block with free dquot entry in quota
                                 * file */
};

/* Structure with global user / group information. We reserve some space
 * for future use. */
struct ocfs2_global_disk_dqblk {
/*00*/  __le32 dqb_id;          /* ID the structure belongs to */
        __le32 dqb_use_count;   /* Number of nodes having reference to this structure */
        __le64 dqb_ihardlimit;  /* absolute limit on allocated inodes */
/*10*/  __le64 dqb_isoftlimit;  /* preferred inode limit */
        __le64 dqb_curinodes;   /* current # allocated inodes */
/*20*/  __le64 dqb_bhardlimit;  /* absolute limit on disk space */
        __le64 dqb_bsoftlimit;  /* preferred limit on disk space */
/*30*/  __le64 dqb_curspace;    /* current space occupied */
        __le64 dqb_btime;       /* time limit for excessive disk use */
/*40*/  __le64 dqb_itime;       /* time limit for excessive inode use */
        __le64 dqb_pad1;
/*50*/  __le64 dqb_pad2;
};

/*
 *  On-disk structures for local quota file
 */

/* Magic numbers and known versions for local quota files */
#define OCFS2_LOCAL_QMAGICS {\
        0x0cf524c0, /* USRQUOTA */ \
        0x0cf524c1  /* GRPQUOTA */ \
}

#define OCFS2_LOCAL_QVERSIONS {\
        0, \
        0, \
}

/* Quota flags in dqinfo header */
#define OLQF_CLEAN      0x0001  /* Quota file is empty (this should be after\
                                 * quota has been cleanly turned off) */

#define OCFS2_LOCAL_INFO_OFF (sizeof(struct ocfs2_disk_dqheader))

/* Information header of local quota file (immediately follows the generic
 * header) */
struct ocfs2_local_disk_dqinfo {
        __le32 dqi_flags;       /* Flags for quota file */
        __le32 dqi_chunks;      /* Number of chunks of quota structures
                                 * with a bitmap */
        __le32 dqi_blocks;      /* Number of blocks allocated for quota file */
};

/* Header of one chunk of a quota file */
struct ocfs2_local_disk_chunk {
        __le32 dqc_free;        /* Number of free entries in the bitmap */
        __u8 dqc_bitmap[0];     /* Bitmap of entries in the corresponding
                                 * chunk of quota file */
};

/* One entry in local quota file */
struct ocfs2_local_disk_dqblk {
/*00*/  __le64 dqb_id;          /* id this quota applies to */
        __le64 dqb_spacemod;    /* Change in the amount of used space */
/*10*/  __le64 dqb_inodemod;    /* Change in the amount of used inodes */
};


/*
 * The quota trailer lives at the end of each quota block.
 */

struct ocfs2_disk_dqtrailer {
/*00*/  struct ocfs2_block_check dq_check;      /* Error checking */
/*08*/  /* Cannot be larger than OCFS2_QBLK_RESERVED_SPACE */
};

static inline struct ocfs2_disk_dqtrailer *ocfs2_block_dqtrailer(int blocksize,
                                                                 void *buf)
{
        char *ptr = buf;
        ptr += blocksize - OCFS2_QBLK_RESERVED_SPACE;

        return (struct ocfs2_disk_dqtrailer *)ptr;
}

#ifdef __KERNEL__
static inline int ocfs2_fast_symlink_chars(struct super_block *sb)
{
        return  sb->s_blocksize -
                 offsetof(struct ocfs2_dinode, id2.i_symlink);
}

static inline int ocfs2_max_inline_data_with_xattr(struct super_block *sb,
                                                   struct ocfs2_dinode *di)
{
        unsigned int xattrsize = le16_to_cpu(di->i_xattr_inline_size);

        if (le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_XATTR_FL)
                return sb->s_blocksize -
                        offsetof(struct ocfs2_dinode, id2.i_data.id_data) -
                        xattrsize;
        else
                return sb->s_blocksize -
                        offsetof(struct ocfs2_dinode, id2.i_data.id_data);
}

static inline int ocfs2_extent_recs_per_inode(struct super_block *sb)
{
        int size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_dinode, id2.i_list.l_recs);

        return size / sizeof(struct ocfs2_extent_rec);
}

static inline int ocfs2_extent_recs_per_inode_with_xattr(
                                                struct super_block *sb,
                                                struct ocfs2_dinode *di)
{
        int size;
        unsigned int xattrsize = le16_to_cpu(di->i_xattr_inline_size);

        if (le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_XATTR_FL)
                size = sb->s_blocksize -
                        offsetof(struct ocfs2_dinode, id2.i_list.l_recs) -
                        xattrsize;
        else
                size = sb->s_blocksize -
                        offsetof(struct ocfs2_dinode, id2.i_list.l_recs);

        return size / sizeof(struct ocfs2_extent_rec);
}

static inline int ocfs2_extent_recs_per_dx_root(struct super_block *sb)
{
        int size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_dx_root_block, dr_list.l_recs);

        return size / sizeof(struct ocfs2_extent_rec);
}

static inline int ocfs2_chain_recs_per_inode(struct super_block *sb)
{
        int size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_dinode, id2.i_chain.cl_recs);

        return size / sizeof(struct ocfs2_chain_rec);
}

static inline u16 ocfs2_extent_recs_per_eb(struct super_block *sb)
{
        int size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_extent_block, h_list.l_recs);

        return size / sizeof(struct ocfs2_extent_rec);
}

static inline u16 ocfs2_extent_recs_per_gd(struct super_block *sb)
{
        int size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_group_desc, bg_list.l_recs);

        return size / sizeof(struct ocfs2_extent_rec);
}

static inline int ocfs2_dx_entries_per_leaf(struct super_block *sb)
{
        int size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_dx_leaf, dl_list.de_entries);

        return size / sizeof(struct ocfs2_dx_entry);
}

static inline int ocfs2_dx_entries_per_root(struct super_block *sb)
{
        int size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_dx_root_block, dr_entries.de_entries);

        return size / sizeof(struct ocfs2_dx_entry);
}

static inline u16 ocfs2_local_alloc_size(struct super_block *sb)
{
        u16 size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_dinode, id2.i_lab.la_bitmap);

        return size;
}

static inline int ocfs2_group_bitmap_size(struct super_block *sb,
                                          int suballocator,
                                          u32 feature_incompat)
{
        int size = sb->s_blocksize -
                offsetof(struct ocfs2_group_desc, bg_bitmap);

        /*
         * The cluster allocator uses the entire block.  Suballocators have
         * never used more than OCFS2_MAX_BG_BITMAP_SIZE.  Unfortunately, older
         * code expects bg_size set to the maximum.  Thus we must keep
         * bg_size as-is unless discontig_bg is enabled.
         */
        if (suballocator &&
            (feature_incompat & OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG))
                size = OCFS2_MAX_BG_BITMAP_SIZE;

        return size;
}

static inline int ocfs2_truncate_recs_per_inode(struct super_block *sb)
{
        int size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_dinode, id2.i_dealloc.tl_recs);

        return size / sizeof(struct ocfs2_truncate_rec);
}

static inline u64 ocfs2_backup_super_blkno(struct super_block *sb, int index)
{
        u64 offset = OCFS2_BACKUP_SB_START;

        if (index >= 0 && index < OCFS2_MAX_BACKUP_SUPERBLOCKS) {
                offset <<= (2 * index);
                offset >>= sb->s_blocksize_bits;
                return offset;
        }

        return 0;

}

static inline u16 ocfs2_xattr_recs_per_xb(struct super_block *sb)
{
        int size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_xattr_block,
                         xb_attrs.xb_root.xt_list.l_recs);

        return size / sizeof(struct ocfs2_extent_rec);
}

static inline u16 ocfs2_extent_recs_per_rb(struct super_block *sb)
{
        int size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_refcount_block, rf_list.l_recs);

        return size / sizeof(struct ocfs2_extent_rec);
}

static inline u16 ocfs2_refcount_recs_per_rb(struct super_block *sb)
{
        int size;

        size = sb->s_blocksize -
                offsetof(struct ocfs2_refcount_block, rf_records.rl_recs);

        return size / sizeof(struct ocfs2_refcount_rec);
}

static inline u32
ocfs2_get_ref_rec_low_cpos(const struct ocfs2_refcount_rec *rec)
{
        return le64_to_cpu(rec->r_cpos) & OCFS2_32BIT_POS_MASK;
}
#else
static inline int ocfs2_fast_symlink_chars(int blocksize)
{
        return blocksize - offsetof(struct ocfs2_dinode, id2.i_symlink);
}

static inline int ocfs2_max_inline_data_with_xattr(int blocksize,
                                                   struct ocfs2_dinode *di)
{
        if (di && (di->i_dyn_features & OCFS2_INLINE_XATTR_FL))
                return blocksize -
                        offsetof(struct ocfs2_dinode, id2.i_data.id_data) -
                        di->i_xattr_inline_size;
        else
                return blocksize -
                        offsetof(struct ocfs2_dinode, id2.i_data.id_data);
}

static inline int ocfs2_extent_recs_per_inode(int blocksize)
{
        int size;

        size = blocksize -
                offsetof(struct ocfs2_dinode, id2.i_list.l_recs);

        return size / sizeof(struct ocfs2_extent_rec);
}

static inline int ocfs2_chain_recs_per_inode(int blocksize)
{
        int size;

        size = blocksize -
                offsetof(struct ocfs2_dinode, id2.i_chain.cl_recs);

        return size / sizeof(struct ocfs2_chain_rec);
}

static inline int ocfs2_extent_recs_per_eb(int blocksize)
{
        int size;

        size = blocksize -
                offsetof(struct ocfs2_extent_block, h_list.l_recs);

        return size / sizeof(struct ocfs2_extent_rec);
}

static inline int ocfs2_extent_recs_per_gd(int blocksize)
{
        int size;

        size = blocksize -
                offsetof(struct ocfs2_group_desc, bg_list.l_recs);

        return size / sizeof(struct ocfs2_extent_rec);
}

static inline int ocfs2_local_alloc_size(int blocksize)
{
        int size;

        size = blocksize -
                offsetof(struct ocfs2_dinode, id2.i_lab.la_bitmap);

        return size;
}

static inline int ocfs2_group_bitmap_size(int blocksize,
                                          int suballocator,
                                          uint32_t feature_incompat)
{
        int size = sb->s_blocksize -
                offsetof(struct ocfs2_group_desc, bg_bitmap);

        /*
         * The cluster allocator uses the entire block.  Suballocators have
         * never used more than OCFS2_MAX_BG_BITMAP_SIZE.  Unfortunately, older
         * code expects bg_size set to the maximum.  Thus we must keep
         * bg_size as-is unless discontig_bg is enabled.
         */
        if (suballocator &&
            (feature_incompat & OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG))
                size = OCFS2_MAX_BG_BITMAP_SIZE;

        return size;
}

static inline int ocfs2_truncate_recs_per_inode(int blocksize)
{
        int size;

        size = blocksize -
                offsetof(struct ocfs2_dinode, id2.i_dealloc.tl_recs);

        return size / sizeof(struct ocfs2_truncate_rec);
}

static inline uint64_t ocfs2_backup_super_blkno(int blocksize, int index)
{
        uint64_t offset = OCFS2_BACKUP_SB_START;

        if (index >= 0 && index < OCFS2_MAX_BACKUP_SUPERBLOCKS) {
                offset <<= (2 * index);
                offset /= blocksize;
                return offset;
        }

        return 0;
}

static inline int ocfs2_xattr_recs_per_xb(int blocksize)
{
        int size;

        size = blocksize -
                offsetof(struct ocfs2_xattr_block,
                         xb_attrs.xb_root.xt_list.l_recs);

        return size / sizeof(struct ocfs2_extent_rec);
}
#endif  /* __KERNEL__ */


static inline int ocfs2_system_inode_is_global(int type)
{
        return ((type >= 0) &&
                (type <= OCFS2_LAST_GLOBAL_SYSTEM_INODE));
}

static inline int ocfs2_sprintf_system_inode_name(char *buf, int len,
                                                  int type, int slot)
{
        int chars;

        /*
         * Global system inodes can only have one copy.  Everything
         * after OCFS2_LAST_GLOBAL_SYSTEM_INODE in the system inode
         * list has a copy per slot.
         */
        if (type <= OCFS2_LAST_GLOBAL_SYSTEM_INODE)
                chars = snprintf(buf, len, "%s",
                                 ocfs2_system_inodes[type].si_name);
        else
                chars = snprintf(buf, len,
                                 ocfs2_system_inodes[type].si_name,
                                 slot);

        return chars;
}

static inline void ocfs2_set_de_type(struct ocfs2_dir_entry *de,
                                    umode_t mode)
{
        de->file_type = ocfs2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
}

static inline int ocfs2_gd_is_discontig(struct ocfs2_group_desc *gd)
{
        if ((offsetof(struct ocfs2_group_desc, bg_bitmap) +
             le16_to_cpu(gd->bg_size)) !=
            offsetof(struct ocfs2_group_desc, bg_list))
                return 0;
        /*
         * Only valid to check l_next_free_rec if
         * bg_bitmap + bg_size == bg_list.
         */
        if (!gd->bg_list.l_next_free_rec)
                return 0;
        return 1;
}
#endif  /* _OCFS2_FS_H */