libxfs/xfs_da_btree.h

   1 /*
   2  * Copyright (c) 2000,2002,2005 Silicon Graphics, Inc.
   3  * Copyright (c) 2013 Red Hat, Inc.
   4  * All Rights Reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it would be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write the Free Software Foundation,
  17  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18  */
  19 #ifndef __XFS_DA_BTREE_H__
  20 #define __XFS_DA_BTREE_H__
  21
  22 struct xfs_defer_ops;
  23 struct xfs_inode;
  24 struct xfs_trans;
  25 struct zone;
  26 struct xfs_dir_ops;
  27
  28 /*
  29  * Directory/attribute geometry information. There will be one of these for each
  30  * data fork type, and it will be passed around via the xfs_da_args. Global
  31  * structures will be attached to the xfs_mount.
  32  */
  33 struct xfs_da_geometry {
  34         int             blksize;        /* da block size in bytes */
  35         int             fsbcount;       /* da block size in filesystem blocks */
  36         uint8_t         fsblog;         /* log2 of _filesystem_ block size */
  37         uint8_t         blklog;         /* log2 of da block size */
  38         uint            node_ents;      /* # of entries in a danode */
  39         int             magicpct;       /* 37% of block size in bytes */
  40         xfs_dablk_t     datablk;        /* blockno of dir data v2 */
  41         xfs_dablk_t     leafblk;        /* blockno of leaf data v2 */
  42         xfs_dablk_t     freeblk;        /* blockno of free data v2 */
  43 };
  44
  45 /*========================================================================
  46  * Btree searching and modification structure definitions.
  47  *========================================================================*/
  48
  49 /*
  50  * Search comparison results
  51  */
  52 enum xfs_dacmp {
  53         XFS_CMP_DIFFERENT,      /* names are completely different */
  54         XFS_CMP_EXACT,          /* names are exactly the same */
  55         XFS_CMP_CASE            /* names are same but differ in case */
  56 };
  57
  58 /*
  59  * Structure to ease passing around component names.
  60  */
  61 typedef struct xfs_da_args {
  62         struct xfs_da_geometry *geo;    /* da block geometry */
  63         const uint8_t           *name;          /* string (maybe not NULL terminated) */
  64         int             namelen;        /* length of string (maybe no NULL) */
  65         uint8_t         filetype;       /* filetype of inode for directories */
  66         uint8_t         *value;         /* set of bytes (maybe contain NULLs) */
  67         int             valuelen;       /* length of value */
  68         int             flags;          /* argument flags (eg: ATTR_NOCREATE) */
  69         xfs_dahash_t    hashval;        /* hash value of name */
  70         xfs_ino_t       inumber;        /* input/output inode number */
  71         struct xfs_inode *dp;           /* directory inode to manipulate */
  72         xfs_fsblock_t   *firstblock;    /* ptr to firstblock for bmap calls */
  73         struct xfs_defer_ops *dfops;    /* ptr to freelist for bmap_finish */
  74         struct xfs_trans *trans;        /* current trans (changes over time) */
  75         xfs_extlen_t    total;          /* total blocks needed, for 1st bmap */
  76         int             whichfork;      /* data or attribute fork */
  77         xfs_dablk_t     blkno;          /* blkno of attr leaf of interest */
  78         int             index;          /* index of attr of interest in blk */
  79         xfs_dablk_t     rmtblkno;       /* remote attr value starting blkno */
  80         int             rmtblkcnt;      /* remote attr value block count */
  81         int             rmtvaluelen;    /* remote attr value length in bytes */
  82         xfs_dablk_t     blkno2;         /* blkno of 2nd attr leaf of interest */
  83         int             index2;         /* index of 2nd attr in blk */
  84         xfs_dablk_t     rmtblkno2;      /* remote attr value starting blkno */
  85         int             rmtblkcnt2;     /* remote attr value block count */
  86         int             rmtvaluelen2;   /* remote attr value length in bytes */
  87         int             op_flags;       /* operation flags */
  88         enum xfs_dacmp  cmpresult;      /* name compare result for lookups */
  89 } xfs_da_args_t;
  90
  91 /*
  92  * Operation flags:
  93  */
  94 #define XFS_DA_OP_JUSTCHECK     0x0001  /* check for ok with no space */
  95 #define XFS_DA_OP_RENAME        0x0002  /* this is an atomic rename op */
  96 #define XFS_DA_OP_ADDNAME       0x0004  /* this is an add operation */
  97 #define XFS_DA_OP_OKNOENT       0x0008  /* lookup/add op, ENOENT ok, else die */
  98 #define XFS_DA_OP_CILOOKUP      0x0010  /* lookup to return CI name if found */
  99
 100 #define XFS_DA_OP_FLAGS \
 101         { XFS_DA_OP_JUSTCHECK,  "JUSTCHECK" }, \
 102         { XFS_DA_OP_RENAME,     "RENAME" }, \
 103         { XFS_DA_OP_ADDNAME,    "ADDNAME" }, \
 104         { XFS_DA_OP_OKNOENT,    "OKNOENT" }, \
 105         { XFS_DA_OP_CILOOKUP,   "CILOOKUP" }
 106
 107 /*
 108  * Storage for holding state during Btree searches and split/join ops.
 109  *
 110  * Only need space for 5 intermediate nodes.  With a minimum of 62-way
 111  * fanout to the Btree, we can support over 900 million directory blocks,
 112  * which is slightly more than enough.
 113  */
 114 typedef struct xfs_da_state_blk {
 115         struct xfs_buf  *bp;            /* buffer containing block */
 116         xfs_dablk_t     blkno;          /* filesystem blkno of buffer */
 117         xfs_daddr_t     disk_blkno;     /* on-disk blkno (in BBs) of buffer */
 118         int             index;          /* relevant index into block */
 119         xfs_dahash_t    hashval;        /* last hash value in block */
 120         int             magic;          /* blk's magic number, ie: blk type */
 121 } xfs_da_state_blk_t;
 122
 123 typedef struct xfs_da_state_path {
 124         int                     active;         /* number of active levels */
 125         xfs_da_state_blk_t      blk[XFS_DA_NODE_MAXDEPTH];
 126 } xfs_da_state_path_t;
 127
 128 typedef struct xfs_da_state {
 129         xfs_da_args_t           *args;          /* filename arguments */
 130         struct xfs_mount        *mp;            /* filesystem mount point */
 131         xfs_da_state_path_t     path;           /* search/split paths */
 132         xfs_da_state_path_t     altpath;        /* alternate path for join */
 133         unsigned char           inleaf;         /* insert into 1->lf, 0->splf */
 134         unsigned char           extravalid;     /* T/F: extrablk is in use */
 135         unsigned char           extraafter;     /* T/F: extrablk is after new */
 136         xfs_da_state_blk_t      extrablk;       /* for double-splits on leaves */
 137                                                 /* for dirv2 extrablk is data */
 138 } xfs_da_state_t;
 139
 140 /*
 141  * Utility macros to aid in logging changed structure fields.
 142  */
 143 #define XFS_DA_LOGOFF(BASE, ADDR)       ((char *)(ADDR) - (char *)(BASE))
 144 #define XFS_DA_LOGRANGE(BASE, ADDR, SIZE)       \
 145                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
 146                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)
 147
 148 /*
 149  * Name ops for directory and/or attr name operations
 150  */
 151 struct xfs_nameops {
 152         xfs_dahash_t    (*hashname)(struct xfs_name *);
 153         enum xfs_dacmp  (*compname)(struct xfs_da_args *,
 154                                         const unsigned char *, int);
 155 };
 156
 157
 158 /*========================================================================
 159  * Function prototypes.
 160  *========================================================================*/
 161
 162 /*
 163  * Routines used for growing the Btree.
 164  */
 165 int     xfs_da3_node_create(struct xfs_da_args *args, xfs_dablk_t blkno,
 166                             int level, struct xfs_buf **bpp, int whichfork);
 167 int     xfs_da3_split(xfs_da_state_t *state);
 168
 169 /*
 170  * Routines used for shrinking the Btree.
 171  */
 172 int     xfs_da3_join(xfs_da_state_t *state);
 173 void    xfs_da3_fixhashpath(struct xfs_da_state *state,
 174                             struct xfs_da_state_path *path_to_to_fix);
 175
 176 /*
 177  * Routines used for finding things in the Btree.
 178  */
 179 int     xfs_da3_node_lookup_int(xfs_da_state_t *state, int *result);
 180 int     xfs_da3_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
 181                                          int forward, int release, int *result);
 182 /*
 183  * Utility routines.
 184  */
 185 int     xfs_da3_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
 186                                        xfs_da_state_blk_t *new_blk);
 187 int     xfs_da3_node_read(struct xfs_trans *tp, struct xfs_inode *dp,
 188                          xfs_dablk_t bno, xfs_daddr_t mappedbno,
 189                          struct xfs_buf **bpp, int which_fork);
 190
 191 /*
 192  * Utility routines.
 193  */
 194 int     xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
 195 int     xfs_da_grow_inode_int(struct xfs_da_args *args, xfs_fileoff_t *bno,
 196                               int count);
 197 int     xfs_da_get_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 198                               xfs_dablk_t bno, xfs_daddr_t mappedbno,
 199                               struct xfs_buf **bp, int whichfork);
 200 int     xfs_da_read_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 201                                xfs_dablk_t bno, xfs_daddr_t mappedbno,
 202                                struct xfs_buf **bpp, int whichfork,
 203                                const struct xfs_buf_ops *ops);
 204 int     xfs_da_reada_buf(struct xfs_inode *dp, xfs_dablk_t bno,
 205                                 xfs_daddr_t mapped_bno, int whichfork,
 206                                 const struct xfs_buf_ops *ops);
 207 int     xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
 208                                           struct xfs_buf *dead_buf);
 209
 210 uint xfs_da_hashname(const uint8_t *name_string, int name_length);
 211 enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
 212                                 const unsigned char *name, int len);
 213
 214
 215 xfs_da_state_t *xfs_da_state_alloc(void);
 216 void xfs_da_state_free(xfs_da_state_t *state);
 217
 218 extern struct kmem_zone *xfs_da_state_zone;
 219 extern const struct xfs_nameops xfs_default_nameops;
 220
 221 #endif  /* __XFS_DA_BTREE_H__ */