Merge tag 'arc-v3.13-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux/fpc-iii.git] / fs / xfs / xfs_da_format.h

/*
 * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
 * Copyright (c) 2013 Red Hat, Inc.
 * 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 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would 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 the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef __XFS_DA_FORMAT_H__
#define __XFS_DA_FORMAT_H__

/*========================================================================
 * Directory Structure when greater than XFS_LBSIZE(mp) bytes.
 *========================================================================*/

/*
 * This structure is common to both leaf nodes and non-leaf nodes in the Btree.
 *
 * It is used to manage a doubly linked list of all blocks at the same
 * level in the Btree, and to identify which type of block this is.
 */
#define XFS_DA_NODE_MAGIC       0xfebe  /* magic number: non-leaf blocks */
#define XFS_ATTR_LEAF_MAGIC     0xfbee  /* magic number: attribute leaf blks */
#define XFS_DIR2_LEAF1_MAGIC    0xd2f1  /* magic number: v2 dirlf single blks */
#define XFS_DIR2_LEAFN_MAGIC    0xd2ff  /* magic number: v2 dirlf multi blks */

typedef struct xfs_da_blkinfo {
        __be32          forw;                   /* previous block in list */
        __be32          back;                   /* following block in list */
        __be16          magic;                  /* validity check on block */
        __be16          pad;                    /* unused */
} xfs_da_blkinfo_t;

/*
 * CRC enabled directory structure types
 *
 * The headers change size for the additional verification information, but
 * otherwise the tree layouts and contents are unchanged. Hence the da btree
 * code can use the struct xfs_da_blkinfo for manipulating the tree links and
 * magic numbers without modification for both v2 and v3 nodes.
 */
#define XFS_DA3_NODE_MAGIC      0x3ebe  /* magic number: non-leaf blocks */
#define XFS_ATTR3_LEAF_MAGIC    0x3bee  /* magic number: attribute leaf blks */
#define XFS_DIR3_LEAF1_MAGIC    0x3df1  /* magic number: v2 dirlf single blks */
#define XFS_DIR3_LEAFN_MAGIC    0x3dff  /* magic number: v2 dirlf multi blks */

struct xfs_da3_blkinfo {
        /*
         * the node link manipulation code relies on the fact that the first
         * element of this structure is the struct xfs_da_blkinfo so it can
         * ignore the differences in the rest of the structures.
         */
        struct xfs_da_blkinfo   hdr;
        __be32                  crc;    /* CRC of block */
        __be64                  blkno;  /* first block of the buffer */
        __be64                  lsn;    /* sequence number of last write */
        uuid_t                  uuid;   /* filesystem we belong to */
        __be64                  owner;  /* inode that owns the block */
};

/*
 * This is the structure of the root and intermediate nodes in the Btree.
 * The leaf nodes are defined above.
 *
 * Entries are not packed.
 *
 * Since we have duplicate keys, use a binary search but always follow
 * all match in the block, not just the first match found.
 */
#define XFS_DA_NODE_MAXDEPTH    5       /* max depth of Btree */

typedef struct xfs_da_node_hdr {
        struct xfs_da_blkinfo   info;   /* block type, links, etc. */
        __be16                  __count; /* count of active entries */
        __be16                  __level; /* level above leaves (leaf == 0) */
} xfs_da_node_hdr_t;

struct xfs_da3_node_hdr {
        struct xfs_da3_blkinfo  info;   /* block type, links, etc. */
        __be16                  __count; /* count of active entries */
        __be16                  __level; /* level above leaves (leaf == 0) */
        __be32                  __pad32;
};

#define XFS_DA3_NODE_CRC_OFF    (offsetof(struct xfs_da3_node_hdr, info.crc))

typedef struct xfs_da_node_entry {
        __be32  hashval;        /* hash value for this descendant */
        __be32  before;         /* Btree block before this key */
} xfs_da_node_entry_t;

typedef struct xfs_da_intnode {
        struct xfs_da_node_hdr  hdr;
        struct xfs_da_node_entry __btree[];
} xfs_da_intnode_t;

struct xfs_da3_intnode {
        struct xfs_da3_node_hdr hdr;
        struct xfs_da_node_entry __btree[];
};

/*
 * In-core version of the node header to abstract the differences in the v2 and
 * v3 disk format of the headers. Callers need to convert to/from disk format as
 * appropriate.
 */
struct xfs_da3_icnode_hdr {
        __uint32_t      forw;
        __uint32_t      back;
        __uint16_t      magic;
        __uint16_t      count;
        __uint16_t      level;
};

#define XFS_LBSIZE(mp)  (mp)->m_sb.sb_blocksize

/*
 * Directory version 2.
 *
 * There are 4 possible formats:
 *  - shortform - embedded into the inode
 *  - single block - data with embedded leaf at the end
 *  - multiple data blocks, single leaf+freeindex block
 *  - data blocks, node and leaf blocks (btree), freeindex blocks
 *
 * Note: many node blocks structures and constants are shared with the attr
 * code and defined in xfs_da_btree.h.
 */

#define XFS_DIR2_BLOCK_MAGIC    0x58443242      /* XD2B: single block dirs */
#define XFS_DIR2_DATA_MAGIC     0x58443244      /* XD2D: multiblock dirs */
#define XFS_DIR2_FREE_MAGIC     0x58443246      /* XD2F: free index blocks */

/*
 * Directory Version 3 With CRCs.
 *
 * The tree formats are the same as for version 2 directories.  The difference
 * is in the block header and dirent formats. In many cases the v3 structures
 * use v2 definitions as they are no different and this makes code sharing much
 * easier.
 *
 * Also, the xfs_dir3_*() functions handle both v2 and v3 formats - if the
 * format is v2 then they switch to the existing v2 code, or the format is v3
 * they implement the v3 functionality. This means the existing dir2 is a mix of
 * xfs_dir2/xfs_dir3 calls and functions. The xfs_dir3 functions are called
 * where there is a difference in the formats, otherwise the code is unchanged.
 *
 * Where it is possible, the code decides what to do based on the magic numbers
 * in the blocks rather than feature bits in the superblock. This means the code
 * is as independent of the external XFS code as possible as doesn't require
 * passing struct xfs_mount pointers into places where it isn't really
 * necessary.
 *
 * Version 3 includes:
 *
 *      - a larger block header for CRC and identification purposes and so the
 *      offsets of all the structures inside the blocks are different.
 *
 *      - new magic numbers to be able to detect the v2/v3 types on the fly.
 */

#define XFS_DIR3_BLOCK_MAGIC    0x58444233      /* XDB3: single block dirs */
#define XFS_DIR3_DATA_MAGIC     0x58444433      /* XDD3: multiblock dirs */
#define XFS_DIR3_FREE_MAGIC     0x58444633      /* XDF3: free index blocks */

/*
 * Dirents in version 3 directories have a file type field. Additions to this
 * list are an on-disk format change, requiring feature bits. Valid values
 * are as follows:
 */
#define XFS_DIR3_FT_UNKNOWN             0
#define XFS_DIR3_FT_REG_FILE            1
#define XFS_DIR3_FT_DIR                 2
#define XFS_DIR3_FT_CHRDEV              3
#define XFS_DIR3_FT_BLKDEV              4
#define XFS_DIR3_FT_FIFO                5
#define XFS_DIR3_FT_SOCK                6
#define XFS_DIR3_FT_SYMLINK             7
#define XFS_DIR3_FT_WHT                 8

#define XFS_DIR3_FT_MAX                 9

/*
 * Byte offset in data block and shortform entry.
 */
typedef __uint16_t      xfs_dir2_data_off_t;
#define NULLDATAOFF     0xffffU
typedef uint            xfs_dir2_data_aoff_t;   /* argument form */

/*
 * Normalized offset (in a data block) of the entry, really xfs_dir2_data_off_t.
 * Only need 16 bits, this is the byte offset into the single block form.
 */
typedef struct { __uint8_t i[2]; } __arch_pack xfs_dir2_sf_off_t;

/*
 * Offset in data space of a data entry.
 */
typedef __uint32_t      xfs_dir2_dataptr_t;
#define XFS_DIR2_MAX_DATAPTR    ((xfs_dir2_dataptr_t)0xffffffff)
#define XFS_DIR2_NULL_DATAPTR   ((xfs_dir2_dataptr_t)0)

/*
 * Byte offset in a directory.
 */
typedef xfs_off_t       xfs_dir2_off_t;

/*
 * Directory block number (logical dirblk in file)
 */
typedef __uint32_t      xfs_dir2_db_t;

/*
 * Inode number stored as 8 8-bit values.
 */
typedef struct { __uint8_t i[8]; } xfs_dir2_ino8_t;

/*
 * Inode number stored as 4 8-bit values.
 * Works a lot of the time, when all the inode numbers in a directory
 * fit in 32 bits.
 */
typedef struct { __uint8_t i[4]; } xfs_dir2_ino4_t;

typedef union {
        xfs_dir2_ino8_t i8;
        xfs_dir2_ino4_t i4;
} xfs_dir2_inou_t;
#define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL)

/*
 * Directory layout when stored internal to an inode.
 *
 * Small directories are packed as tightly as possible so as to fit into the
 * literal area of the inode.  These "shortform" directories consist of a
 * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry
 * structures.  Due the different inode number storage size and the variable
 * length name field in the xfs_dir2_sf_entry all these structure are
 * variable length, and the accessors in this file should be used to iterate
 * over them.
 */
typedef struct xfs_dir2_sf_hdr {
        __uint8_t               count;          /* count of entries */
        __uint8_t               i8count;        /* count of 8-byte inode #s */
        xfs_dir2_inou_t         parent;         /* parent dir inode number */
} __arch_pack xfs_dir2_sf_hdr_t;

typedef struct xfs_dir2_sf_entry {
        __u8                    namelen;        /* actual name length */
        xfs_dir2_sf_off_t       offset;         /* saved offset */
        __u8                    name[];         /* name, variable size */
        /*
         * A single byte containing the file type field follows the inode
         * number for version 3 directory entries.
         *
         * A xfs_dir2_ino8_t or xfs_dir2_ino4_t follows here, at a
         * variable offset after the name.
         */
} __arch_pack xfs_dir2_sf_entry_t;

static inline int xfs_dir2_sf_hdr_size(int i8count)
{
        return sizeof(struct xfs_dir2_sf_hdr) -
                (i8count == 0) *
                (sizeof(xfs_dir2_ino8_t) - sizeof(xfs_dir2_ino4_t));
}

static inline xfs_dir2_data_aoff_t
xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
{
        return get_unaligned_be16(&sfep->offset.i);
}

static inline void
xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
{
        put_unaligned_be16(off, &sfep->offset.i);
}

static inline struct xfs_dir2_sf_entry *
xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
{
        return (struct xfs_dir2_sf_entry *)
                ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
}

/*
 * Data block structures.
 *
 * A pure data block looks like the following drawing on disk:
 *
 *    +-------------------------------------------------+
 *    | xfs_dir2_data_hdr_t                             |
 *    +-------------------------------------------------+
 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 *    | ...                                             |
 *    +-------------------------------------------------+
 *    | unused space                                    |
 *    +-------------------------------------------------+
 *
 * As all the entries are variable size structures the accessors below should
 * be used to iterate over them.
 *
 * In addition to the pure data blocks for the data and node formats,
 * most structures are also used for the combined data/freespace "block"
 * format below.
 */

#define XFS_DIR2_DATA_ALIGN_LOG 3               /* i.e., 8 bytes */
#define XFS_DIR2_DATA_ALIGN     (1 << XFS_DIR2_DATA_ALIGN_LOG)
#define XFS_DIR2_DATA_FREE_TAG  0xffff
#define XFS_DIR2_DATA_FD_COUNT  3

/*
 * Directory address space divided into sections,
 * spaces separated by 32GB.
 */
#define XFS_DIR2_SPACE_SIZE     (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
#define XFS_DIR2_DATA_SPACE     0
#define XFS_DIR2_DATA_OFFSET    (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
#define XFS_DIR2_DATA_FIRSTDB(mp)       \
        xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET)

/*
 * Describe a free area in the data block.
 *
 * The freespace will be formatted as a xfs_dir2_data_unused_t.
 */
typedef struct xfs_dir2_data_free {
        __be16                  offset;         /* start of freespace */
        __be16                  length;         /* length of freespace */
} xfs_dir2_data_free_t;

/*
 * Header for the data blocks.
 *
 * The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
 */
typedef struct xfs_dir2_data_hdr {
        __be32                  magic;          /* XFS_DIR2_DATA_MAGIC or */
                                                /* XFS_DIR2_BLOCK_MAGIC */
        xfs_dir2_data_free_t    bestfree[XFS_DIR2_DATA_FD_COUNT];
} xfs_dir2_data_hdr_t;

/*
 * define a structure for all the verification fields we are adding to the
 * directory block structures. This will be used in several structures.
 * The magic number must be the first entry to align with all the dir2
 * structures so we determine how to decode them just by the magic number.
 */
struct xfs_dir3_blk_hdr {
        __be32                  magic;  /* magic number */
        __be32                  crc;    /* CRC of block */
        __be64                  blkno;  /* first block of the buffer */
        __be64                  lsn;    /* sequence number of last write */
        uuid_t                  uuid;   /* filesystem we belong to */
        __be64                  owner;  /* inode that owns the block */
};

struct xfs_dir3_data_hdr {
        struct xfs_dir3_blk_hdr hdr;
        xfs_dir2_data_free_t    best_free[XFS_DIR2_DATA_FD_COUNT];
        __be32                  pad;    /* 64 bit alignment */
};

#define XFS_DIR3_DATA_CRC_OFF  offsetof(struct xfs_dir3_data_hdr, hdr.crc)

/*
 * Active entry in a data block.
 *
 * Aligned to 8 bytes.  After the variable length name field there is a
 * 2 byte tag field, which can be accessed using xfs_dir3_data_entry_tag_p.
 *
 * For dir3 structures, there is file type field between the name and the tag.
 * This can only be manipulated by helper functions. It is packed hard against
 * the end of the name so any padding for rounding is between the file type and
 * the tag.
 */
typedef struct xfs_dir2_data_entry {
        __be64                  inumber;        /* inode number */
        __u8                    namelen;        /* name length */
        __u8                    name[];         /* name bytes, no null */
     /* __u8                    filetype; */    /* type of inode we point to */
     /* __be16                  tag; */         /* starting offset of us */
} xfs_dir2_data_entry_t;

/*
 * Unused entry in a data block.
 *
 * Aligned to 8 bytes.  Tag appears as the last 2 bytes and must be accessed
 * using xfs_dir2_data_unused_tag_p.
 */
typedef struct xfs_dir2_data_unused {
        __be16                  freetag;        /* XFS_DIR2_DATA_FREE_TAG */
        __be16                  length;         /* total free length */
                                                /* variable offset */
        __be16                  tag;            /* starting offset of us */
} xfs_dir2_data_unused_t;

/*
 * Pointer to a freespace's tag word.
 */
static inline __be16 *
xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup)
{
        return (__be16 *)((char *)dup +
                        be16_to_cpu(dup->length) - sizeof(__be16));
}

/*
 * Leaf block structures.
 *
 * A pure leaf block looks like the following drawing on disk:
 *
 *    +---------------------------+
 *    | xfs_dir2_leaf_hdr_t       |
 *    +---------------------------+
 *    | xfs_dir2_leaf_entry_t     |
 *    | xfs_dir2_leaf_entry_t     |
 *    | xfs_dir2_leaf_entry_t     |
 *    | xfs_dir2_leaf_entry_t     |
 *    | ...                       |
 *    +---------------------------+
 *    | xfs_dir2_data_off_t       |
 *    | xfs_dir2_data_off_t       |
 *    | xfs_dir2_data_off_t       |
 *    | ...                       |
 *    +---------------------------+
 *    | xfs_dir2_leaf_tail_t      |
 *    +---------------------------+
 *
 * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block
 * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present
 * for directories with separate leaf nodes and free space blocks
 * (magic = XFS_DIR2_LEAFN_MAGIC).
 *
 * As all the entries are variable size structures the accessors below should
 * be used to iterate over them.
 */

/*
 * Offset of the leaf/node space.  First block in this space
 * is the btree root.
 */
#define XFS_DIR2_LEAF_SPACE     1
#define XFS_DIR2_LEAF_OFFSET    (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE)
#define XFS_DIR2_LEAF_FIRSTDB(mp)       \
        xfs_dir2_byte_to_db(mp, XFS_DIR2_LEAF_OFFSET)

/*
 * Leaf block header.
 */
typedef struct xfs_dir2_leaf_hdr {
        xfs_da_blkinfo_t        info;           /* header for da routines */
        __be16                  count;          /* count of entries */
        __be16                  stale;          /* count of stale entries */
} xfs_dir2_leaf_hdr_t;

struct xfs_dir3_leaf_hdr {
        struct xfs_da3_blkinfo  info;           /* header for da routines */
        __be16                  count;          /* count of entries */
        __be16                  stale;          /* count of stale entries */
        __be32                  pad;            /* 64 bit alignment */
};

struct xfs_dir3_icleaf_hdr {
        __uint32_t              forw;
        __uint32_t              back;
        __uint16_t              magic;
        __uint16_t              count;
        __uint16_t              stale;
};

/*
 * Leaf block entry.
 */
typedef struct xfs_dir2_leaf_entry {
        __be32                  hashval;        /* hash value of name */
        __be32                  address;        /* address of data entry */
} xfs_dir2_leaf_entry_t;

/*
 * Leaf block tail.
 */
typedef struct xfs_dir2_leaf_tail {
        __be32                  bestcount;
} xfs_dir2_leaf_tail_t;

/*
 * Leaf block.
 */
typedef struct xfs_dir2_leaf {
        xfs_dir2_leaf_hdr_t     hdr;                    /* leaf header */
        xfs_dir2_leaf_entry_t   __ents[];               /* entries */
} xfs_dir2_leaf_t;

struct xfs_dir3_leaf {
        struct xfs_dir3_leaf_hdr        hdr;            /* leaf header */
        struct xfs_dir2_leaf_entry      __ents[];       /* entries */
};

#define XFS_DIR3_LEAF_CRC_OFF  offsetof(struct xfs_dir3_leaf_hdr, info.crc)

/*
 * Get address of the bestcount field in the single-leaf block.
 */
static inline struct xfs_dir2_leaf_tail *
xfs_dir2_leaf_tail_p(struct xfs_mount *mp, struct xfs_dir2_leaf *lp)
{
        return (struct xfs_dir2_leaf_tail *)
                ((char *)lp + mp->m_dirblksize -
                  sizeof(struct xfs_dir2_leaf_tail));
}

/*
 * Get address of the bests array in the single-leaf block.
 */
static inline __be16 *
xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp)
{
        return (__be16 *)ltp - be32_to_cpu(ltp->bestcount);
}

/*
 * DB blocks here are logical directory block numbers, not filesystem blocks.
 */

/*
 * Convert dataptr to byte in file space
 */
static inline xfs_dir2_off_t
xfs_dir2_dataptr_to_byte(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
{
        return (xfs_dir2_off_t)dp << XFS_DIR2_DATA_ALIGN_LOG;
}

/*
 * Convert byte in file space to dataptr.  It had better be aligned.
 */
static inline xfs_dir2_dataptr_t
xfs_dir2_byte_to_dataptr(struct xfs_mount *mp, xfs_dir2_off_t by)
{
        return (xfs_dir2_dataptr_t)(by >> XFS_DIR2_DATA_ALIGN_LOG);
}

/*
 * Convert byte in space to (DB) block
 */
static inline xfs_dir2_db_t
xfs_dir2_byte_to_db(struct xfs_mount *mp, xfs_dir2_off_t by)
{
        return (xfs_dir2_db_t)
                (by >> (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog));
}

/*
 * Convert dataptr to a block number
 */
static inline xfs_dir2_db_t
xfs_dir2_dataptr_to_db(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
{
        return xfs_dir2_byte_to_db(mp, xfs_dir2_dataptr_to_byte(mp, dp));
}

/*
 * Convert byte in space to offset in a block
 */
static inline xfs_dir2_data_aoff_t
xfs_dir2_byte_to_off(struct xfs_mount *mp, xfs_dir2_off_t by)
{
        return (xfs_dir2_data_aoff_t)(by &
                ((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) - 1));
}

/*
 * Convert dataptr to a byte offset in a block
 */
static inline xfs_dir2_data_aoff_t
xfs_dir2_dataptr_to_off(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
{
        return xfs_dir2_byte_to_off(mp, xfs_dir2_dataptr_to_byte(mp, dp));
}

/*
 * Convert block and offset to byte in space
 */
static inline xfs_dir2_off_t
xfs_dir2_db_off_to_byte(struct xfs_mount *mp, xfs_dir2_db_t db,
                        xfs_dir2_data_aoff_t o)
{
        return ((xfs_dir2_off_t)db <<
                (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) + o;
}

/*
 * Convert block (DB) to block (dablk)
 */
static inline xfs_dablk_t
xfs_dir2_db_to_da(struct xfs_mount *mp, xfs_dir2_db_t db)
{
        return (xfs_dablk_t)(db << mp->m_sb.sb_dirblklog);
}

/*
 * Convert byte in space to (DA) block
 */
static inline xfs_dablk_t
xfs_dir2_byte_to_da(struct xfs_mount *mp, xfs_dir2_off_t by)
{
        return xfs_dir2_db_to_da(mp, xfs_dir2_byte_to_db(mp, by));
}

/*
 * Convert block and offset to dataptr
 */
static inline xfs_dir2_dataptr_t
xfs_dir2_db_off_to_dataptr(struct xfs_mount *mp, xfs_dir2_db_t db,
                           xfs_dir2_data_aoff_t o)
{
        return xfs_dir2_byte_to_dataptr(mp, xfs_dir2_db_off_to_byte(mp, db, o));
}

/*
 * Convert block (dablk) to block (DB)
 */
static inline xfs_dir2_db_t
xfs_dir2_da_to_db(struct xfs_mount *mp, xfs_dablk_t da)
{
        return (xfs_dir2_db_t)(da >> mp->m_sb.sb_dirblklog);
}

/*
 * Convert block (dablk) to byte offset in space
 */
static inline xfs_dir2_off_t
xfs_dir2_da_to_byte(struct xfs_mount *mp, xfs_dablk_t da)
{
        return xfs_dir2_db_off_to_byte(mp, xfs_dir2_da_to_db(mp, da), 0);
}

/*
 * Free space block defintions for the node format.
 */

/*
 * Offset of the freespace index.
 */
#define XFS_DIR2_FREE_SPACE     2
#define XFS_DIR2_FREE_OFFSET    (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE)
#define XFS_DIR2_FREE_FIRSTDB(mp)       \
        xfs_dir2_byte_to_db(mp, XFS_DIR2_FREE_OFFSET)

typedef struct xfs_dir2_free_hdr {
        __be32                  magic;          /* XFS_DIR2_FREE_MAGIC */
        __be32                  firstdb;        /* db of first entry */
        __be32                  nvalid;         /* count of valid entries */
        __be32                  nused;          /* count of used entries */
} xfs_dir2_free_hdr_t;

typedef struct xfs_dir2_free {
        xfs_dir2_free_hdr_t     hdr;            /* block header */
        __be16                  bests[];        /* best free counts */
                                                /* unused entries are -1 */
} xfs_dir2_free_t;

struct xfs_dir3_free_hdr {
        struct xfs_dir3_blk_hdr hdr;
        __be32                  firstdb;        /* db of first entry */
        __be32                  nvalid;         /* count of valid entries */
        __be32                  nused;          /* count of used entries */
        __be32                  pad;            /* 64 bit alignment */
};

struct xfs_dir3_free {
        struct xfs_dir3_free_hdr hdr;
        __be16                  bests[];        /* best free counts */
                                                /* unused entries are -1 */
};

#define XFS_DIR3_FREE_CRC_OFF  offsetof(struct xfs_dir3_free, hdr.hdr.crc)

/*
 * In core version of the free block header, abstracted away from on-disk format
 * differences. Use this in the code, and convert to/from the disk version using
 * xfs_dir3_free_hdr_from_disk/xfs_dir3_free_hdr_to_disk.
 */
struct xfs_dir3_icfree_hdr {
        __uint32_t      magic;
        __uint32_t      firstdb;
        __uint32_t      nvalid;
        __uint32_t      nused;

};

/*
 * Single block format.
 *
 * The single block format looks like the following drawing on disk:
 *
 *    +-------------------------------------------------+
 *    | xfs_dir2_data_hdr_t                             |
 *    +-------------------------------------------------+
 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t :
 *    | ...                                             |
 *    +-------------------------------------------------+
 *    | unused space                                    |
 *    +-------------------------------------------------+
 *    | ...                                             |
 *    | xfs_dir2_leaf_entry_t                           |
 *    | xfs_dir2_leaf_entry_t                           |
 *    +-------------------------------------------------+
 *    | xfs_dir2_block_tail_t                           |
 *    +-------------------------------------------------+
 *
 * As all the entries are variable size structures the accessors below should
 * be used to iterate over them.
 */

typedef struct xfs_dir2_block_tail {
        __be32          count;                  /* count of leaf entries */
        __be32          stale;                  /* count of stale lf entries */
} xfs_dir2_block_tail_t;

/*
 * Pointer to the leaf header embedded in a data block (1-block format)
 */
static inline struct xfs_dir2_block_tail *
xfs_dir2_block_tail_p(struct xfs_mount *mp, struct xfs_dir2_data_hdr *hdr)
{
        return ((struct xfs_dir2_block_tail *)
                ((char *)hdr + mp->m_dirblksize)) - 1;
}

/*
 * Pointer to the leaf entries embedded in a data block (1-block format)
 */
static inline struct xfs_dir2_leaf_entry *
xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp)
{
        return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count);
}


/*
 * Attribute storage layout
 *
 * Attribute lists are structured around Btrees where all the data
 * elements are in the leaf nodes.  Attribute names are hashed into an int,
 * then that int is used as the index into the Btree.  Since the hashval
 * of an attribute name may not be unique, we may have duplicate keys.  The
 * internal links in the Btree are logical block offsets into the file.
 *
 *========================================================================
 * Attribute structure when equal to XFS_LBSIZE(mp) bytes.
 *========================================================================
 *
 * Struct leaf_entry's are packed from the top.  Name/values grow from the
 * bottom but are not packed.  The freemap contains run-length-encoded entries
 * for the free bytes after the leaf_entry's, but only the N largest such,
 * smaller runs are dropped.  When the freemap doesn't show enough space
 * for an allocation, we compact the name/value area and try again.  If we
 * still don't have enough space, then we have to split the block.  The
 * name/value structs (both local and remote versions) must be 32bit aligned.
 *
 * Since we have duplicate hash keys, for each key that matches, compare
 * the actual name string.  The root and intermediate node search always
 * takes the first-in-the-block key match found, so we should only have
 * to work "forw"ard.  If none matches, continue with the "forw"ard leaf
 * nodes until the hash key changes or the attribute name is found.
 *
 * We store the fact that an attribute is a ROOT/USER/SECURE attribute in
 * the leaf_entry.  The namespaces are independent only because we also look
 * at the namespace bit when we are looking for a matching attribute name.
 *
 * We also store an "incomplete" bit in the leaf_entry.  It shows that an
 * attribute is in the middle of being created and should not be shown to
 * the user if we crash during the time that the bit is set.  We clear the
 * bit when we have finished setting up the attribute.  We do this because
 * we cannot create some large attributes inside a single transaction, and we
 * need some indication that we weren't finished if we crash in the middle.
 */
#define XFS_ATTR_LEAF_MAPSIZE   3       /* how many freespace slots */

typedef struct xfs_attr_leaf_map {      /* RLE map of free bytes */
        __be16  base;                     /* base of free region */
        __be16  size;                     /* length of free region */
} xfs_attr_leaf_map_t;

typedef struct xfs_attr_leaf_hdr {      /* constant-structure header block */
        xfs_da_blkinfo_t info;          /* block type, links, etc. */
        __be16  count;                  /* count of active leaf_entry's */
        __be16  usedbytes;              /* num bytes of names/values stored */
        __be16  firstused;              /* first used byte in name area */
        __u8    holes;                  /* != 0 if blk needs compaction */
        __u8    pad1;
        xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE];
                                        /* N largest free regions */
} xfs_attr_leaf_hdr_t;

typedef struct xfs_attr_leaf_entry {    /* sorted on key, not name */
        __be32  hashval;                /* hash value of name */
        __be16  nameidx;                /* index into buffer of name/value */
        __u8    flags;                  /* LOCAL/ROOT/SECURE/INCOMPLETE flag */
        __u8    pad2;                   /* unused pad byte */
} xfs_attr_leaf_entry_t;

typedef struct xfs_attr_leaf_name_local {
        __be16  valuelen;               /* number of bytes in value */
        __u8    namelen;                /* length of name bytes */
        __u8    nameval[1];             /* name/value bytes */
} xfs_attr_leaf_name_local_t;

typedef struct xfs_attr_leaf_name_remote {
        __be32  valueblk;               /* block number of value bytes */
        __be32  valuelen;               /* number of bytes in value */
        __u8    namelen;                /* length of name bytes */
        __u8    name[1];                /* name bytes */
} xfs_attr_leaf_name_remote_t;

typedef struct xfs_attr_leafblock {
        xfs_attr_leaf_hdr_t     hdr;    /* constant-structure header block */
        xfs_attr_leaf_entry_t   entries[1];     /* sorted on key, not name */
        xfs_attr_leaf_name_local_t namelist;    /* grows from bottom of buf */
        xfs_attr_leaf_name_remote_t valuelist;  /* grows from bottom of buf */
} xfs_attr_leafblock_t;

/*
 * CRC enabled leaf structures. Called "version 3" structures to match the
 * version number of the directory and dablk structures for this feature, and
 * attr2 is already taken by the variable inode attribute fork size feature.
 */
struct xfs_attr3_leaf_hdr {
        struct xfs_da3_blkinfo  info;
        __be16                  count;
        __be16                  usedbytes;
        __be16                  firstused;
        __u8                    holes;
        __u8                    pad1;
        struct xfs_attr_leaf_map freemap[XFS_ATTR_LEAF_MAPSIZE];
        __be32                  pad2;           /* 64 bit alignment */
};

#define XFS_ATTR3_LEAF_CRC_OFF  (offsetof(struct xfs_attr3_leaf_hdr, info.crc))

struct xfs_attr3_leafblock {
        struct xfs_attr3_leaf_hdr       hdr;
        struct xfs_attr_leaf_entry      entries[1];

        /*
         * The rest of the block contains the following structures after the
         * leaf entries, growing from the bottom up. The variables are never
         * referenced, the locations accessed purely from helper functions.
         *
         * struct xfs_attr_leaf_name_local
         * struct xfs_attr_leaf_name_remote
         */
};

/*
 * incore, neutral version of the attribute leaf header
 */
struct xfs_attr3_icleaf_hdr {
        __uint32_t      forw;
        __uint32_t      back;
        __uint16_t      magic;
        __uint16_t      count;
        __uint16_t      usedbytes;
        __uint16_t      firstused;
        __u8            holes;
        struct {
                __uint16_t      base;
                __uint16_t      size;
        } freemap[XFS_ATTR_LEAF_MAPSIZE];
};

/*
 * Flags used in the leaf_entry[i].flags field.
 * NOTE: the INCOMPLETE bit must not collide with the flags bits specified
 * on the system call, they are "or"ed together for various operations.
 */
#define XFS_ATTR_LOCAL_BIT      0       /* attr is stored locally */
#define XFS_ATTR_ROOT_BIT       1       /* limit access to trusted attrs */
#define XFS_ATTR_SECURE_BIT     2       /* limit access to secure attrs */
#define XFS_ATTR_INCOMPLETE_BIT 7       /* attr in middle of create/delete */
#define XFS_ATTR_LOCAL          (1 << XFS_ATTR_LOCAL_BIT)
#define XFS_ATTR_ROOT           (1 << XFS_ATTR_ROOT_BIT)
#define XFS_ATTR_SECURE         (1 << XFS_ATTR_SECURE_BIT)
#define XFS_ATTR_INCOMPLETE     (1 << XFS_ATTR_INCOMPLETE_BIT)

/*
 * Conversion macros for converting namespace bits from argument flags
 * to ondisk flags.
 */
#define XFS_ATTR_NSP_ARGS_MASK          (ATTR_ROOT | ATTR_SECURE)
#define XFS_ATTR_NSP_ONDISK_MASK        (XFS_ATTR_ROOT | XFS_ATTR_SECURE)
#define XFS_ATTR_NSP_ONDISK(flags)      ((flags) & XFS_ATTR_NSP_ONDISK_MASK)
#define XFS_ATTR_NSP_ARGS(flags)        ((flags) & XFS_ATTR_NSP_ARGS_MASK)
#define XFS_ATTR_NSP_ARGS_TO_ONDISK(x)  (((x) & ATTR_ROOT ? XFS_ATTR_ROOT : 0) |\
                                         ((x) & ATTR_SECURE ? XFS_ATTR_SECURE : 0))
#define XFS_ATTR_NSP_ONDISK_TO_ARGS(x)  (((x) & XFS_ATTR_ROOT ? ATTR_ROOT : 0) |\
                                         ((x) & XFS_ATTR_SECURE ? ATTR_SECURE : 0))

/*
 * Alignment for namelist and valuelist entries (since they are mixed
 * there can be only one alignment value)
 */
#define XFS_ATTR_LEAF_NAME_ALIGN        ((uint)sizeof(xfs_dablk_t))

static inline int
xfs_attr3_leaf_hdr_size(struct xfs_attr_leafblock *leafp)
{
        if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
                return sizeof(struct xfs_attr3_leaf_hdr);
        return sizeof(struct xfs_attr_leaf_hdr);
}

static inline struct xfs_attr_leaf_entry *
xfs_attr3_leaf_entryp(xfs_attr_leafblock_t *leafp)
{
        if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
                return &((struct xfs_attr3_leafblock *)leafp)->entries[0];
        return &leafp->entries[0];
}

/*
 * Cast typed pointers for "local" and "remote" name/value structs.
 */
static inline char *
xfs_attr3_leaf_name(xfs_attr_leafblock_t *leafp, int idx)
{
        struct xfs_attr_leaf_entry *entries = xfs_attr3_leaf_entryp(leafp);

        return &((char *)leafp)[be16_to_cpu(entries[idx].nameidx)];
}

static inline xfs_attr_leaf_name_remote_t *
xfs_attr3_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx)
{
        return (xfs_attr_leaf_name_remote_t *)xfs_attr3_leaf_name(leafp, idx);
}

static inline xfs_attr_leaf_name_local_t *
xfs_attr3_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx)
{
        return (xfs_attr_leaf_name_local_t *)xfs_attr3_leaf_name(leafp, idx);
}

/*
 * Calculate total bytes used (including trailing pad for alignment) for
 * a "local" name/value structure, a "remote" name/value structure, and
 * a pointer which might be either.
 */
static inline int xfs_attr_leaf_entsize_remote(int nlen)
{
        return ((uint)sizeof(xfs_attr_leaf_name_remote_t) - 1 + (nlen) + \
                XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1);
}

static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen)
{
        return ((uint)sizeof(xfs_attr_leaf_name_local_t) - 1 + (nlen) + (vlen) +
                XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1);
}

static inline int xfs_attr_leaf_entsize_local_max(int bsize)
{
        return (((bsize) >> 1) + ((bsize) >> 2));
}



/*
 * Remote attribute block format definition
 *
 * There is one of these headers per filesystem block in a remote attribute.
 * This is done to ensure there is a 1:1 mapping between the attribute value
 * length and the number of blocks needed to store the attribute. This makes the
 * verification of a buffer a little more complex, but greatly simplifies the
 * allocation, reading and writing of these attributes as we don't have to guess
 * the number of blocks needed to store the attribute data.
 */
#define XFS_ATTR3_RMT_MAGIC     0x5841524d      /* XARM */

struct xfs_attr3_rmt_hdr {
        __be32  rm_magic;
        __be32  rm_offset;
        __be32  rm_bytes;
        __be32  rm_crc;
        uuid_t  rm_uuid;
        __be64  rm_owner;
        __be64  rm_blkno;
        __be64  rm_lsn;
};

#define XFS_ATTR3_RMT_CRC_OFF   offsetof(struct xfs_attr3_rmt_hdr, rm_crc)

#define XFS_ATTR3_RMT_BUF_SPACE(mp, bufsize)    \
        ((bufsize) - (xfs_sb_version_hascrc(&(mp)->m_sb) ? \
                        sizeof(struct xfs_attr3_rmt_hdr) : 0))

#endif /* __XFS_DA_FORMAT_H__ */