xfs_da_btree.h

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/*
 * Copyright (c) 2000,2002,2005 Silicon Graphics, 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_buf;
struct xfs_bmap_free;
struct xfs_inode;
struct xfs_mount;
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;

/*
 * 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_intnode {
    struct xfs_da_node_hdr {    /* constant-structure header block */
        xfs_da_blkinfo_t info;  /* block type, links, etc. */
        __be16  count;      /* count of active entries */
        __be16  level;      /* level above leaves (leaf == 0) */
    } hdr;
    struct xfs_da_node_entry {
        __be32  hashval;    /* hash value for this descendant */
        __be32  before;     /* Btree block before this key */
    } btree[1];         /* variable sized array of keys */
} xfs_da_intnode_t;
typedef struct xfs_da_node_hdr xfs_da_node_hdr_t;
typedef struct xfs_da_node_entry xfs_da_node_entry_t;

#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_da_node_create(xfs_da_args_t *args, xfs_dablk_t blkno, int level,
                     struct xfs_buf **bpp, int whichfork);
int xfs_da_split(xfs_da_state_t *state);

/*
 * Routines used for shrinking the Btree.
 */
int xfs_da_join(xfs_da_state_t *state);
void    xfs_da_fixhashpath(xfs_da_state_t *state,
                      xfs_da_state_path_t *path_to_to_fix);

/*
 * Routines used for finding things in the Btree.
 */
int xfs_da_node_lookup_int(xfs_da_state_t *state, int *result);
int xfs_da_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
                     int forward, int release, int *result);
/*
 * Utility routines.
 */
int xfs_da_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
                       xfs_da_state_blk_t *new_blk);

/*
 * 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);
xfs_daddr_t xfs_da_reada_buf(struct xfs_trans *trans, struct xfs_inode *dp,
            xfs_dablk_t bno, int whichfork);
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__ */