fs/xfs/xfs_da_btree.h

   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
  21 struct xfs_buf;
  22 struct xfs_bmap_free;
  23 struct xfs_inode;
  24 struct xfs_mount;
  25 struct xfs_trans;
  26 struct 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  * Is 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
  43 typedef 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
  61 typedef 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;
  72 typedef struct xfs_da_node_hdr xfs_da_node_hdr_t;
  73 typedef 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  */
  84 enum 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  */
  93 typedef 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 /*
 129  * Structure to describe buffer(s) for a block.
 130  * This is needed in the directory version 2 format case, when
 131  * multiple non-contiguous fsblocks might be needed to cover one
 132  * logical directory block.
 133  * If the buffer count is 1 then the data pointer points to the
 134  * same place as the b_addr field for the buffer, else to kmem_alloced memory.
 135  */
 136 typedef struct xfs_dabuf {
 137         int             nbuf;           /* number of buffer pointers present */
 138         short           dirty;          /* data needs to be copied back */
 139         short           bbcount;        /* how large is data in bbs */
 140         void            *data;          /* pointer for buffers' data */
 141 #ifdef XFS_DABUF_DEBUG
 142         inst_t          *ra;            /* return address of caller to make */
 143         struct xfs_dabuf *next;         /* next in global chain */
 144         struct xfs_dabuf *prev;         /* previous in global chain */
 145         struct xfs_buftarg *target;     /* device for buffer */
 146         xfs_daddr_t     blkno;          /* daddr first in bps[0] */
 147 #endif
 148         struct xfs_buf  *bps[1];        /* actually nbuf of these */
 149 } xfs_dabuf_t;
 150 #define XFS_DA_BUF_SIZE(n)      \
 151         (sizeof(xfs_dabuf_t) + sizeof(struct xfs_buf *) * ((n) - 1))
 152
 153 #ifdef XFS_DABUF_DEBUG
 154 extern xfs_dabuf_t      *xfs_dabuf_global_list;
 155 #endif
 156
 157 /*
 158  * Storage for holding state during Btree searches and split/join ops.
 159  *
 160  * Only need space for 5 intermediate nodes.  With a minimum of 62-way
 161  * fanout to the Btree, we can support over 900 million directory blocks,
 162  * which is slightly more than enough.
 163  */
 164 typedef struct xfs_da_state_blk {
 165         xfs_dabuf_t     *bp;            /* buffer containing block */
 166         xfs_dablk_t     blkno;          /* filesystem blkno of buffer */
 167         xfs_daddr_t     disk_blkno;     /* on-disk blkno (in BBs) of buffer */
 168         int             index;          /* relevant index into block */
 169         xfs_dahash_t    hashval;        /* last hash value in block */
 170         int             magic;          /* blk's magic number, ie: blk type */
 171 } xfs_da_state_blk_t;
 172
 173 typedef struct xfs_da_state_path {
 174         int                     active;         /* number of active levels */
 175         xfs_da_state_blk_t      blk[XFS_DA_NODE_MAXDEPTH];
 176 } xfs_da_state_path_t;
 177
 178 typedef struct xfs_da_state {
 179         xfs_da_args_t           *args;          /* filename arguments */
 180         struct xfs_mount        *mp;            /* filesystem mount point */
 181         unsigned int            blocksize;      /* logical block size */
 182         unsigned int            node_ents;      /* how many entries in danode */
 183         xfs_da_state_path_t     path;           /* search/split paths */
 184         xfs_da_state_path_t     altpath;        /* alternate path for join */
 185         unsigned char           inleaf;         /* insert into 1->lf, 0->splf */
 186         unsigned char           extravalid;     /* T/F: extrablk is in use */
 187         unsigned char           extraafter;     /* T/F: extrablk is after new */
 188         xfs_da_state_blk_t      extrablk;       /* for double-splits on leaves */
 189                                                 /* for dirv2 extrablk is data */
 190 } xfs_da_state_t;
 191
 192 /*
 193  * Utility macros to aid in logging changed structure fields.
 194  */
 195 #define XFS_DA_LOGOFF(BASE, ADDR)       ((char *)(ADDR) - (char *)(BASE))
 196 #define XFS_DA_LOGRANGE(BASE, ADDR, SIZE)       \
 197                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
 198                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)
 199
 200 /*
 201  * Name ops for directory and/or attr name operations
 202  */
 203 struct xfs_nameops {
 204         xfs_dahash_t    (*hashname)(struct xfs_name *);
 205         enum xfs_dacmp  (*compname)(struct xfs_da_args *, const char *, int);
 206 };
 207
 208
 209 /*========================================================================
 210  * Function prototypes.
 211  *========================================================================*/
 212
 213 /*
 214  * Routines used for growing the Btree.
 215  */
 216 int     xfs_da_node_create(xfs_da_args_t *args, xfs_dablk_t blkno, int level,
 217                                          xfs_dabuf_t **bpp, int whichfork);
 218 int     xfs_da_split(xfs_da_state_t *state);
 219
 220 /*
 221  * Routines used for shrinking the Btree.
 222  */
 223 int     xfs_da_join(xfs_da_state_t *state);
 224 void    xfs_da_fixhashpath(xfs_da_state_t *state,
 225                                           xfs_da_state_path_t *path_to_to_fix);
 226
 227 /*
 228  * Routines used for finding things in the Btree.
 229  */
 230 int     xfs_da_node_lookup_int(xfs_da_state_t *state, int *result);
 231 int     xfs_da_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
 232                                          int forward, int release, int *result);
 233 /*
 234  * Utility routines.
 235  */
 236 int     xfs_da_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
 237                                        xfs_da_state_blk_t *new_blk);
 238
 239 /*
 240  * Utility routines.
 241  */
 242 int     xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
 243 int     xfs_da_get_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 244                               xfs_dablk_t bno, xfs_daddr_t mappedbno,
 245                               xfs_dabuf_t **bp, int whichfork);
 246 int     xfs_da_read_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 247                                xfs_dablk_t bno, xfs_daddr_t mappedbno,
 248                                xfs_dabuf_t **bpp, int whichfork);
 249 xfs_daddr_t     xfs_da_reada_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 250                         xfs_dablk_t bno, int whichfork);
 251 int     xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
 252                                           xfs_dabuf_t *dead_buf);
 253
 254 uint xfs_da_hashname(const __uint8_t *name_string, int name_length);
 255 enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
 256                                 const char *name, int len);
 257
 258
 259 xfs_da_state_t *xfs_da_state_alloc(void);
 260 void xfs_da_state_free(xfs_da_state_t *state);
 261
 262 void xfs_da_buf_done(xfs_dabuf_t *dabuf);
 263 void xfs_da_log_buf(struct xfs_trans *tp, xfs_dabuf_t *dabuf, uint first,
 264                            uint last);
 265 void xfs_da_brelse(struct xfs_trans *tp, xfs_dabuf_t *dabuf);
 266 void xfs_da_binval(struct xfs_trans *tp, xfs_dabuf_t *dabuf);
 267 xfs_daddr_t xfs_da_blkno(xfs_dabuf_t *dabuf);
 268
 269 extern struct kmem_zone *xfs_da_state_zone;
 270 extern struct kmem_zone *xfs_dabuf_zone;
 271 extern const struct xfs_nameops xfs_default_nameops;
 272
 273 #endif  /* __XFS_DA_BTREE_H__ */