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_bmap_free;
  22 struct xfs_inode;
  23 struct xfs_mount;
  24 struct xfs_trans;
  25 struct zone;
  26
  27 /*========================================================================
  28  * Directory Structure when greater than XFS_LBSIZE(mp) bytes.
  29  *========================================================================*/
  30
  31 /*
  32  * This structure is common to both leaf nodes and non-leaf nodes in the Btree.
  33  *
  34  * It is used to manage a doubly linked list of all blocks at the same
  35  * level in the Btree, and to identify which type of block this is.
  36  */
  37 #define XFS_DA_NODE_MAGIC       0xfebe  /* magic number: non-leaf blocks */
  38 #define XFS_ATTR_LEAF_MAGIC     0xfbee  /* magic number: attribute leaf blks */
  39 #define XFS_DIR2_LEAF1_MAGIC    0xd2f1  /* magic number: v2 dirlf single blks */
  40 #define XFS_DIR2_LEAFN_MAGIC    0xd2ff  /* magic number: v2 dirlf multi blks */
  41
  42 typedef struct xfs_da_blkinfo {
  43         __be32          forw;                   /* previous block in list */
  44         __be32          back;                   /* following block in list */
  45         __be16          magic;                  /* validity check on block */
  46         __be16          pad;                    /* unused */
  47 } xfs_da_blkinfo_t;
  48
  49 /*
  50  * This is the structure of the root and intermediate nodes in the Btree.
  51  * The leaf nodes are defined above.
  52  *
  53  * Entries are not packed.
  54  *
  55  * Since we have duplicate keys, use a binary search but always follow
  56  * all match in the block, not just the first match found.
  57  */
  58 #define XFS_DA_NODE_MAXDEPTH    5       /* max depth of Btree */
  59
  60 typedef struct xfs_da_intnode {
  61         struct xfs_da_node_hdr {        /* constant-structure header block */
  62                 xfs_da_blkinfo_t info;  /* block type, links, etc. */
  63                 __be16  count;          /* count of active entries */
  64                 __be16  level;          /* level above leaves (leaf == 0) */
  65         } hdr;
  66         struct xfs_da_node_entry {
  67                 __be32  hashval;        /* hash value for this descendant */
  68                 __be32  before;         /* Btree block before this key */
  69         } btree[1];                     /* variable sized array of keys */
  70 } xfs_da_intnode_t;
  71 typedef struct xfs_da_node_hdr xfs_da_node_hdr_t;
  72 typedef struct xfs_da_node_entry xfs_da_node_entry_t;
  73
  74 #define XFS_LBSIZE(mp)  (mp)->m_sb.sb_blocksize
  75
  76 /*========================================================================
  77  * Btree searching and modification structure definitions.
  78  *========================================================================*/
  79
  80 /*
  81  * Search comparison results
  82  */
  83 enum xfs_dacmp {
  84         XFS_CMP_DIFFERENT,      /* names are completely different */
  85         XFS_CMP_EXACT,          /* names are exactly the same */
  86         XFS_CMP_CASE            /* names are same but differ in case */
  87 };
  88
  89 /*
  90  * Structure to ease passing around component names.
  91  */
  92 typedef struct xfs_da_args {
  93         const __uint8_t *name;          /* string (maybe not NULL terminated) */
  94         int             namelen;        /* length of string (maybe no NULL) */
  95         __uint8_t       *value;         /* set of bytes (maybe contain NULLs) */
  96         int             valuelen;       /* length of value */
  97         int             flags;          /* argument flags (eg: ATTR_NOCREATE) */
  98         xfs_dahash_t    hashval;        /* hash value of name */
  99         xfs_ino_t       inumber;        /* input/output inode number */
 100         struct xfs_inode *dp;           /* directory inode to manipulate */
 101         xfs_fsblock_t   *firstblock;    /* ptr to firstblock for bmap calls */
 102         struct xfs_bmap_free *flist;    /* ptr to freelist for bmap_finish */
 103         struct xfs_trans *trans;        /* current trans (changes over time) */
 104         xfs_extlen_t    total;          /* total blocks needed, for 1st bmap */
 105         int             whichfork;      /* data or attribute fork */
 106         xfs_dablk_t     blkno;          /* blkno of attr leaf of interest */
 107         int             index;          /* index of attr of interest in blk */
 108         xfs_dablk_t     rmtblkno;       /* remote attr value starting blkno */
 109         int             rmtblkcnt;      /* remote attr value block count */
 110         xfs_dablk_t     blkno2;         /* blkno of 2nd attr leaf of interest */
 111         int             index2;         /* index of 2nd attr in blk */
 112         xfs_dablk_t     rmtblkno2;      /* remote attr value starting blkno */
 113         int             rmtblkcnt2;     /* remote attr value block count */
 114         int             op_flags;       /* operation flags */
 115         enum xfs_dacmp  cmpresult;      /* name compare result for lookups */
 116 } xfs_da_args_t;
 117
 118 /*
 119  * Operation flags:
 120  */
 121 #define XFS_DA_OP_JUSTCHECK     0x0001  /* check for ok with no space */
 122 #define XFS_DA_OP_RENAME        0x0002  /* this is an atomic rename op */
 123 #define XFS_DA_OP_ADDNAME       0x0004  /* this is an add operation */
 124 #define XFS_DA_OP_OKNOENT       0x0008  /* lookup/add op, ENOENT ok, else die */
 125 #define XFS_DA_OP_CILOOKUP      0x0010  /* lookup to return CI name if found */
 126
 127 #define XFS_DA_OP_FLAGS \
 128         { XFS_DA_OP_JUSTCHECK,  "JUSTCHECK" }, \
 129         { XFS_DA_OP_RENAME,     "RENAME" }, \
 130         { XFS_DA_OP_ADDNAME,    "ADDNAME" }, \
 131         { XFS_DA_OP_OKNOENT,    "OKNOENT" }, \
 132         { XFS_DA_OP_CILOOKUP,   "CILOOKUP" }
 133
 134 /*
 135  * Storage for holding state during Btree searches and split/join ops.
 136  *
 137  * Only need space for 5 intermediate nodes.  With a minimum of 62-way
 138  * fanout to the Btree, we can support over 900 million directory blocks,
 139  * which is slightly more than enough.
 140  */
 141 typedef struct xfs_da_state_blk {
 142         struct xfs_buf  *bp;            /* buffer containing block */
 143         xfs_dablk_t     blkno;          /* filesystem blkno of buffer */
 144         xfs_daddr_t     disk_blkno;     /* on-disk blkno (in BBs) of buffer */
 145         int             index;          /* relevant index into block */
 146         xfs_dahash_t    hashval;        /* last hash value in block */
 147         int             magic;          /* blk's magic number, ie: blk type */
 148 } xfs_da_state_blk_t;
 149
 150 typedef struct xfs_da_state_path {
 151         int                     active;         /* number of active levels */
 152         xfs_da_state_blk_t      blk[XFS_DA_NODE_MAXDEPTH];
 153 } xfs_da_state_path_t;
 154
 155 typedef struct xfs_da_state {
 156         xfs_da_args_t           *args;          /* filename arguments */
 157         struct xfs_mount        *mp;            /* filesystem mount point */
 158         unsigned int            blocksize;      /* logical block size */
 159         unsigned int            node_ents;      /* how many entries in danode */
 160         xfs_da_state_path_t     path;           /* search/split paths */
 161         xfs_da_state_path_t     altpath;        /* alternate path for join */
 162         unsigned char           inleaf;         /* insert into 1->lf, 0->splf */
 163         unsigned char           extravalid;     /* T/F: extrablk is in use */
 164         unsigned char           extraafter;     /* T/F: extrablk is after new */
 165         xfs_da_state_blk_t      extrablk;       /* for double-splits on leaves */
 166                                                 /* for dirv2 extrablk is data */
 167 } xfs_da_state_t;
 168
 169 /*
 170  * Utility macros to aid in logging changed structure fields.
 171  */
 172 #define XFS_DA_LOGOFF(BASE, ADDR)       ((char *)(ADDR) - (char *)(BASE))
 173 #define XFS_DA_LOGRANGE(BASE, ADDR, SIZE)       \
 174                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
 175                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)
 176
 177 /*
 178  * Name ops for directory and/or attr name operations
 179  */
 180 struct xfs_nameops {
 181         xfs_dahash_t    (*hashname)(struct xfs_name *);
 182         enum xfs_dacmp  (*compname)(struct xfs_da_args *,
 183                                         const unsigned char *, int);
 184 };
 185
 186
 187 /*========================================================================
 188  * Function prototypes.
 189  *========================================================================*/
 190
 191 /*
 192  * Routines used for growing the Btree.
 193  */
 194 int     xfs_da_node_create(xfs_da_args_t *args, xfs_dablk_t blkno, int level,
 195                                          struct xfs_buf **bpp, int whichfork);
 196 int     xfs_da_split(xfs_da_state_t *state);
 197
 198 /*
 199  * Routines used for shrinking the Btree.
 200  */
 201 int     xfs_da_join(xfs_da_state_t *state);
 202 void    xfs_da_fixhashpath(xfs_da_state_t *state,
 203                                           xfs_da_state_path_t *path_to_to_fix);
 204
 205 /*
 206  * Routines used for finding things in the Btree.
 207  */
 208 int     xfs_da_node_lookup_int(xfs_da_state_t *state, int *result);
 209 int     xfs_da_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
 210                                          int forward, int release, int *result);
 211 /*
 212  * Utility routines.
 213  */
 214 int     xfs_da_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
 215                                        xfs_da_state_blk_t *new_blk);
 216 int     xfs_da_node_read(struct xfs_trans *tp, struct xfs_inode *dp,
 217                          xfs_dablk_t bno, xfs_daddr_t mappedbno,
 218                          struct xfs_buf **bpp, int which_fork);
 219
 220 /*
 221  * Utility routines.
 222  */
 223 int     xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
 224 int     xfs_da_grow_inode_int(struct xfs_da_args *args, xfs_fileoff_t *bno,
 225                               int count);
 226 int     xfs_da_get_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 227                               xfs_dablk_t bno, xfs_daddr_t mappedbno,
 228                               struct xfs_buf **bp, int whichfork);
 229 int     xfs_da_read_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 230                                xfs_dablk_t bno, xfs_daddr_t mappedbno,
 231                                struct xfs_buf **bpp, int whichfork,
 232                                const struct xfs_buf_ops *ops);
 233 xfs_daddr_t     xfs_da_reada_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 234                                 xfs_dablk_t bno, xfs_daddr_t mapped_bno,
 235                                 int whichfork, const struct xfs_buf_ops *ops);
 236 int     xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
 237                                           struct xfs_buf *dead_buf);
 238
 239 uint xfs_da_hashname(const __uint8_t *name_string, int name_length);
 240 enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
 241                                 const unsigned char *name, int len);
 242
 243
 244 xfs_da_state_t *xfs_da_state_alloc(void);
 245 void xfs_da_state_free(xfs_da_state_t *state);
 246
 247 extern struct kmem_zone *xfs_da_state_zone;
 248 extern const struct xfs_nameops xfs_default_nameops;
 249
 250 #endif  /* __XFS_DA_BTREE_H__ */