/*
 * Copyright (c) 2000,2002,2005 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_BTREE_H__
#define __XFS_DA_BTREE_H__

struct xfs_bmap_free;
struct xfs_inode;
struct xfs_trans;
struct zone;

/*========================================================================
 * 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;
};

extern void xfs_da3_node_hdr_from_disk(struct xfs_da3_icnode_hdr *to,
                                       struct xfs_da_intnode *from);
extern void xfs_da3_node_hdr_to_disk(struct xfs_da_intnode *to,
                                     struct xfs_da3_icnode_hdr *from);

static inline int
xfs_da3_node_hdr_size(struct xfs_da_intnode *dap)
{
        if (dap->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC))
                return sizeof(struct xfs_da3_node_hdr);
        return sizeof(struct xfs_da_node_hdr);
}

static inline struct xfs_da_node_entry *
xfs_da3_node_tree_p(struct xfs_da_intnode *dap)
{
        if (dap->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC)) {
                struct xfs_da3_intnode *dap3 = (struct xfs_da3_intnode *)dap;
                return dap3->__btree;
        }
        return dap->__btree;
}

extern void xfs_da3_intnode_from_disk(struct xfs_da3_icnode_hdr *to,
                                      struct xfs_da_intnode *from);
extern void xfs_da3_intnode_to_disk(struct xfs_da_intnode *to,
                                    struct xfs_da3_icnode_hdr *from);

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

/*========================================================================
 * Btree searching and modification structure definitions.
 *========================================================================*/

/*
 * Search comparison results
 */
enum xfs_dacmp {
        XFS_CMP_DIFFERENT,      /* names are completely different */
        XFS_CMP_EXACT,          /* names are exactly the same */
        XFS_CMP_CASE            /* names are same but differ in case */
};

/*
 * Structure to ease passing around component names.
 */
typedef struct xfs_da_args {
        const __uint8_t *name;          /* string (maybe not NULL terminated) */
        int             namelen;        /* length of string (maybe no NULL) */
        __uint8_t       *value;         /* set of bytes (maybe contain NULLs) */
        int             valuelen;       /* length of value */
        int             flags;          /* argument flags (eg: ATTR_NOCREATE) */
        xfs_dahash_t    hashval;        /* hash value of name */
        xfs_ino_t       inumber;        /* input/output inode number */
        struct xfs_inode *dp;           /* directory inode to manipulate */
        xfs_fsblock_t   *firstblock;    /* ptr to firstblock for bmap calls */
        struct xfs_bmap_free *flist;    /* ptr to freelist for bmap_finish */
        struct xfs_trans *trans;        /* current trans (changes over time) */
        xfs_extlen_t    total;          /* total blocks needed, for 1st bmap */
        int             whichfork;      /* data or attribute fork */
        xfs_dablk_t     blkno;          /* blkno of attr leaf of interest */
        int             index;          /* index of attr of interest in blk */
        xfs_dablk_t     rmtblkno;       /* remote attr value starting blkno */
        int             rmtblkcnt;      /* remote attr value block count */
        xfs_dablk_t     blkno2;         /* blkno of 2nd attr leaf of interest */
        int             index2;         /* index of 2nd attr in blk */
        xfs_dablk_t     rmtblkno2;      /* remote attr value starting blkno */
        int             rmtblkcnt2;     /* remote attr value block count */
        int             op_flags;       /* operation flags */
        enum xfs_dacmp  cmpresult;      /* name compare result for lookups */
} xfs_da_args_t;

/*
 * Operation flags:
 */
#define XFS_DA_OP_JUSTCHECK     0x0001  /* check for ok with no space */
#define XFS_DA_OP_RENAME        0x0002  /* this is an atomic rename op */
#define XFS_DA_OP_ADDNAME       0x0004  /* this is an add operation */
#define XFS_DA_OP_OKNOENT       0x0008  /* lookup/add op, ENOENT ok, else die */
#define XFS_DA_OP_CILOOKUP      0x0010  /* lookup to return CI name if found */

#define XFS_DA_OP_FLAGS \
        { XFS_DA_OP_JUSTCHECK,  "JUSTCHECK" }, \
        { XFS_DA_OP_RENAME,     "RENAME" }, \
        { XFS_DA_OP_ADDNAME,    "ADDNAME" }, \
        { XFS_DA_OP_OKNOENT,    "OKNOENT" }, \
        { XFS_DA_OP_CILOOKUP,   "CILOOKUP" }

/*
 * Storage for holding state during Btree searches and split/join ops.
 *
 * Only need space for 5 intermediate nodes.  With a minimum of 62-way
 * fanout to the Btree, we can support over 900 million directory blocks,
 * which is slightly more than enough.
 */
typedef struct xfs_da_state_blk {
        struct xfs_buf  *bp;            /* buffer containing block */
        xfs_dablk_t     blkno;          /* filesystem blkno of buffer */
        xfs_daddr_t     disk_blkno;     /* on-disk blkno (in BBs) of buffer */
        int             index;          /* relevant index into block */
        xfs_dahash_t    hashval;        /* last hash value in block */
        int             magic;          /* blk's magic number, ie: blk type */
} xfs_da_state_blk_t;

typedef struct xfs_da_state_path {
        int                     active;         /* number of active levels */
        xfs_da_state_blk_t      blk[XFS_DA_NODE_MAXDEPTH];
} xfs_da_state_path_t;

typedef struct xfs_da_state {
        xfs_da_args_t           *args;          /* filename arguments */
        struct xfs_mount        *mp;            /* filesystem mount point */
        unsigned int            blocksize;      /* logical block size */
        unsigned int            node_ents;      /* how many entries in danode */
        xfs_da_state_path_t     path;           /* search/split paths */
        xfs_da_state_path_t     altpath;        /* alternate path for join */
        unsigned char           inleaf;         /* insert into 1->lf, 0->splf */
        unsigned char           extravalid;     /* T/F: extrablk is in use */
        unsigned char           extraafter;     /* T/F: extrablk is after new */
        xfs_da_state_blk_t      extrablk;       /* for double-splits on leaves */
                                                /* for dirv2 extrablk is data */
} xfs_da_state_t;

/*
 * Utility macros to aid in logging changed structure fields.
 */
#define XFS_DA_LOGOFF(BASE, ADDR)       ((char *)(ADDR) - (char *)(BASE))
#define XFS_DA_LOGRANGE(BASE, ADDR, SIZE)       \
                (uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
                (uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)

/*
 * Name ops for directory and/or attr name operations
 */
struct xfs_nameops {
        xfs_dahash_t    (*hashname)(struct xfs_name *);
        enum xfs_dacmp  (*compname)(struct xfs_da_args *,
                                        const unsigned char *, int);
};


/*========================================================================
 * Function prototypes.
 *========================================================================*/

/*
 * Routines used for growing the Btree.
 */
int     xfs_da3_node_create(struct xfs_da_args *args, xfs_dablk_t blkno,
                            int level, struct xfs_buf **bpp, int whichfork);
int     xfs_da3_split(xfs_da_state_t *state);

/*
 * Routines used for shrinking the Btree.
 */
int     xfs_da3_join(xfs_da_state_t *state);
void    xfs_da3_fixhashpath(struct xfs_da_state *state,
                            struct xfs_da_state_path *path_to_to_fix);

/*
 * Routines used for finding things in the Btree.
 */
int     xfs_da3_node_lookup_int(xfs_da_state_t *state, int *result);
int     xfs_da3_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
                                         int forward, int release, int *result);
/*
 * Utility routines.
 */
int     xfs_da3_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
                                       xfs_da_state_blk_t *new_blk);
int     xfs_da3_node_read(struct xfs_trans *tp, struct xfs_inode *dp,
                         xfs_dablk_t bno, xfs_daddr_t mappedbno,
                         struct xfs_buf **bpp, int which_fork);

extern const struct xfs_buf_ops xfs_da3_node_buf_ops;

/*
 * Utility routines.
 */
int     xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
int     xfs_da_grow_inode_int(struct xfs_da_args *args, xfs_fileoff_t *bno,
                              int count);
int     xfs_da_get_buf(struct xfs_trans *trans, struct xfs_inode *dp,
                              xfs_dablk_t bno, xfs_daddr_t mappedbno,
                              struct xfs_buf **bp, int whichfork);
int     xfs_da_read_buf(struct xfs_trans *trans, struct xfs_inode *dp,
                               xfs_dablk_t bno, xfs_daddr_t mappedbno,
                               struct xfs_buf **bpp, int whichfork,
                               const struct xfs_buf_ops *ops);
xfs_daddr_t     xfs_da_reada_buf(struct xfs_trans *trans, struct xfs_inode *dp,
                                xfs_dablk_t bno, xfs_daddr_t mapped_bno,
                                int whichfork, const struct xfs_buf_ops *ops);
int     xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
                                          struct xfs_buf *dead_buf);

uint xfs_da_hashname(const __uint8_t *name_string, int name_length);
enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
                                const unsigned char *name, int len);


xfs_da_state_t *xfs_da_state_alloc(void);
void xfs_da_state_free(xfs_da_state_t *state);

extern struct kmem_zone *xfs_da_state_zone;
extern const struct xfs_nameops xfs_default_nameops;

#endif  /* __XFS_DA_BTREE_H__ */