linux/fs/xfs/xfs_da_btree.h
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   1/*
   2 * Copyright (c) 2000,2002,2005 Silicon Graphics, Inc.
   3 * All Rights Reserved.
   4 *
   5 * This program is free software; you can redistribute it and/or
   6 * modify it under the terms of the GNU General Public License as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it would be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write the Free Software Foundation,
  16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17 */
  18#ifndef __XFS_DA_BTREE_H__
  19#define __XFS_DA_BTREE_H__
  20
  21struct xfs_buf;
  22struct xfs_bmap_free;
  23struct xfs_inode;
  24struct xfs_mount;
  25struct xfs_trans;
  26struct zone;
  27
  28/*========================================================================
  29 * Directory Structure when greater than XFS_LBSIZE(mp) bytes.
  30 *========================================================================*/
  31
  32/*
  33 * This structure is common to both leaf nodes and non-leaf nodes in the Btree.
  34 *
  35 * It is used to manage a doubly linked list of all blocks at the same
  36 * level in the Btree, and to identify which type of block this is.
  37 */
  38#define XFS_DA_NODE_MAGIC       0xfebe  /* magic number: non-leaf blocks */
  39#define XFS_ATTR_LEAF_MAGIC     0xfbee  /* magic number: attribute leaf blks */
  40#define XFS_DIR2_LEAF1_MAGIC    0xd2f1  /* magic number: v2 dirlf single blks */
  41#define XFS_DIR2_LEAFN_MAGIC    0xd2ff  /* magic number: v2 dirlf multi blks */
  42
  43typedef struct xfs_da_blkinfo {
  44        __be32          forw;                   /* previous block in list */
  45        __be32          back;                   /* following block in list */
  46        __be16          magic;                  /* validity check on block */
  47        __be16          pad;                    /* unused */
  48} xfs_da_blkinfo_t;
  49
  50/*
  51 * This is the structure of the root and intermediate nodes in the Btree.
  52 * The leaf nodes are defined above.
  53 *
  54 * Entries are not packed.
  55 *
  56 * Since we have duplicate keys, use a binary search but always follow
  57 * all match in the block, not just the first match found.
  58 */
  59#define XFS_DA_NODE_MAXDEPTH    5       /* max depth of Btree */
  60
  61typedef struct xfs_da_intnode {
  62        struct xfs_da_node_hdr {        /* constant-structure header block */
  63                xfs_da_blkinfo_t info;  /* block type, links, etc. */
  64                __be16  count;          /* count of active entries */
  65                __be16  level;          /* level above leaves (leaf == 0) */
  66        } hdr;
  67        struct xfs_da_node_entry {
  68                __be32  hashval;        /* hash value for this descendant */
  69                __be32  before;         /* Btree block before this key */
  70        } btree[1];                     /* variable sized array of keys */
  71} xfs_da_intnode_t;
  72typedef struct xfs_da_node_hdr xfs_da_node_hdr_t;
  73typedef struct xfs_da_node_entry xfs_da_node_entry_t;
  74
  75#define XFS_LBSIZE(mp)  (mp)->m_sb.sb_blocksize
  76
  77/*========================================================================
  78 * Btree searching and modification structure definitions.
  79 *========================================================================*/
  80
  81/*
  82 * Search comparison results
  83 */
  84enum xfs_dacmp {
  85        XFS_CMP_DIFFERENT,      /* names are completely different */
  86        XFS_CMP_EXACT,          /* names are exactly the same */
  87        XFS_CMP_CASE            /* names are same but differ in case */
  88};
  89
  90/*
  91 * Structure to ease passing around component names.
  92 */
  93typedef struct xfs_da_args {
  94        const __uint8_t *name;          /* string (maybe not NULL terminated) */
  95        int             namelen;        /* length of string (maybe no NULL) */
  96        __uint8_t       *value;         /* set of bytes (maybe contain NULLs) */
  97        int             valuelen;       /* length of value */
  98        int             flags;          /* argument flags (eg: ATTR_NOCREATE) */
  99        xfs_dahash_t    hashval;        /* hash value of name */
 100        xfs_ino_t       inumber;        /* input/output inode number */
 101        struct xfs_inode *dp;           /* directory inode to manipulate */
 102        xfs_fsblock_t   *firstblock;    /* ptr to firstblock for bmap calls */
 103        struct xfs_bmap_free *flist;    /* ptr to freelist for bmap_finish */
 104        struct xfs_trans *trans;        /* current trans (changes over time) */
 105        xfs_extlen_t    total;          /* total blocks needed, for 1st bmap */
 106        int             whichfork;      /* data or attribute fork */
 107        xfs_dablk_t     blkno;          /* blkno of attr leaf of interest */
 108        int             index;          /* index of attr of interest in blk */
 109        xfs_dablk_t     rmtblkno;       /* remote attr value starting blkno */
 110        int             rmtblkcnt;      /* remote attr value block count */
 111        xfs_dablk_t     blkno2;         /* blkno of 2nd attr leaf of interest */
 112        int             index2;         /* index of 2nd attr in blk */
 113        xfs_dablk_t     rmtblkno2;      /* remote attr value starting blkno */
 114        int             rmtblkcnt2;     /* remote attr value block count */
 115        int             op_flags;       /* operation flags */
 116        enum xfs_dacmp  cmpresult;      /* name compare result for lookups */
 117} xfs_da_args_t;
 118
 119/*
 120 * Operation flags:
 121 */
 122#define XFS_DA_OP_JUSTCHECK     0x0001  /* check for ok with no space */
 123#define XFS_DA_OP_RENAME        0x0002  /* this is an atomic rename op */
 124#define XFS_DA_OP_ADDNAME       0x0004  /* this is an add operation */
 125#define XFS_DA_OP_OKNOENT       0x0008  /* lookup/add op, ENOENT ok, else die */
 126#define XFS_DA_OP_CILOOKUP      0x0010  /* lookup to return CI name if found */
 127
 128#define XFS_DA_OP_FLAGS \
 129        { XFS_DA_OP_JUSTCHECK,  "JUSTCHECK" }, \
 130        { XFS_DA_OP_RENAME,     "RENAME" }, \
 131        { XFS_DA_OP_ADDNAME,    "ADDNAME" }, \
 132        { XFS_DA_OP_OKNOENT,    "OKNOENT" }, \
 133        { XFS_DA_OP_CILOOKUP,   "CILOOKUP" }
 134
 135/*
 136 * Storage for holding state during Btree searches and split/join ops.
 137 *
 138 * Only need space for 5 intermediate nodes.  With a minimum of 62-way
 139 * fanout to the Btree, we can support over 900 million directory blocks,
 140 * which is slightly more than enough.
 141 */
 142typedef struct xfs_da_state_blk {
 143        struct xfs_buf  *bp;            /* buffer containing block */
 144        xfs_dablk_t     blkno;          /* filesystem blkno of buffer */
 145        xfs_daddr_t     disk_blkno;     /* on-disk blkno (in BBs) of buffer */
 146        int             index;          /* relevant index into block */
 147        xfs_dahash_t    hashval;        /* last hash value in block */
 148        int             magic;          /* blk's magic number, ie: blk type */
 149} xfs_da_state_blk_t;
 150
 151typedef struct xfs_da_state_path {
 152        int                     active;         /* number of active levels */
 153        xfs_da_state_blk_t      blk[XFS_DA_NODE_MAXDEPTH];
 154} xfs_da_state_path_t;
 155
 156typedef struct xfs_da_state {
 157        xfs_da_args_t           *args;          /* filename arguments */
 158        struct xfs_mount        *mp;            /* filesystem mount point */
 159        unsigned int            blocksize;      /* logical block size */
 160        unsigned int            node_ents;      /* how many entries in danode */
 161        xfs_da_state_path_t     path;           /* search/split paths */
 162        xfs_da_state_path_t     altpath;        /* alternate path for join */
 163        unsigned char           inleaf;         /* insert into 1->lf, 0->splf */
 164        unsigned char           extravalid;     /* T/F: extrablk is in use */
 165        unsigned char           extraafter;     /* T/F: extrablk is after new */
 166        xfs_da_state_blk_t      extrablk;       /* for double-splits on leaves */
 167                                                /* for dirv2 extrablk is data */
 168} xfs_da_state_t;
 169
 170/*
 171 * Utility macros to aid in logging changed structure fields.
 172 */
 173#define XFS_DA_LOGOFF(BASE, ADDR)       ((char *)(ADDR) - (char *)(BASE))
 174#define XFS_DA_LOGRANGE(BASE, ADDR, SIZE)       \
 175                (uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
 176                (uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)
 177
 178/*
 179 * Name ops for directory and/or attr name operations
 180 */
 181struct xfs_nameops {
 182        xfs_dahash_t    (*hashname)(struct xfs_name *);
 183        enum xfs_dacmp  (*compname)(struct xfs_da_args *,
 184                                        const unsigned char *, int);
 185};
 186
 187
 188/*========================================================================
 189 * Function prototypes.
 190 *========================================================================*/
 191
 192/*
 193 * Routines used for growing the Btree.
 194 */
 195int     xfs_da_node_create(xfs_da_args_t *args, xfs_dablk_t blkno, int level,
 196                                         struct xfs_buf **bpp, int whichfork);
 197int     xfs_da_split(xfs_da_state_t *state);
 198
 199/*
 200 * Routines used for shrinking the Btree.
 201 */
 202int     xfs_da_join(xfs_da_state_t *state);
 203void    xfs_da_fixhashpath(xfs_da_state_t *state,
 204                                          xfs_da_state_path_t *path_to_to_fix);
 205
 206/*
 207 * Routines used for finding things in the Btree.
 208 */
 209int     xfs_da_node_lookup_int(xfs_da_state_t *state, int *result);
 210int     xfs_da_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
 211                                         int forward, int release, int *result);
 212/*
 213 * Utility routines.
 214 */
 215int     xfs_da_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
 216                                       xfs_da_state_blk_t *new_blk);
 217
 218/*
 219 * Utility routines.
 220 */
 221int     xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
 222int     xfs_da_grow_inode_int(struct xfs_da_args *args, xfs_fileoff_t *bno,
 223                              int count);
 224int     xfs_da_get_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 225                              xfs_dablk_t bno, xfs_daddr_t mappedbno,
 226                              struct xfs_buf **bp, int whichfork);
 227int     xfs_da_read_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 228                               xfs_dablk_t bno, xfs_daddr_t mappedbno,
 229                               struct xfs_buf **bpp, int whichfork);
 230xfs_daddr_t     xfs_da_reada_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 231                        xfs_dablk_t bno, int whichfork);
 232int     xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
 233                                          struct xfs_buf *dead_buf);
 234
 235uint xfs_da_hashname(const __uint8_t *name_string, int name_length);
 236enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
 237                                const unsigned char *name, int len);
 238
 239
 240xfs_da_state_t *xfs_da_state_alloc(void);
 241void xfs_da_state_free(xfs_da_state_t *state);
 242
 243extern struct kmem_zone *xfs_da_state_zone;
 244extern const struct xfs_nameops xfs_default_nameops;
 245
 246#endif  /* __XFS_DA_BTREE_H__ */
 247
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