libxfs/xfs_da_btree.h

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2000,2002,2005 Silicon Graphics, Inc.
   4  * Copyright (c) 2013 Red Hat, Inc.
   5  * All Rights Reserved.
   6  */
   7 #ifndef __XFS_DA_BTREE_H__
   8 #define __XFS_DA_BTREE_H__
   9
  10 struct xfs_inode;
  11 struct xfs_trans;
  12 struct zone;
  13 struct xfs_dir_ops;
  14
  15 /*
  16  * Directory/attribute geometry information. There will be one of these for each
  17  * data fork type, and it will be passed around via the xfs_da_args. Global
  18  * structures will be attached to the xfs_mount.
  19  */
  20 struct xfs_da_geometry {
  21         int             blksize;        /* da block size in bytes */
  22         int             fsbcount;       /* da block size in filesystem blocks */
  23         uint8_t         fsblog;         /* log2 of _filesystem_ block size */
  24         uint8_t         blklog;         /* log2 of da block size */
  25         uint            node_ents;      /* # of entries in a danode */
  26         int             magicpct;       /* 37% of block size in bytes */
  27         xfs_dablk_t     datablk;        /* blockno of dir data v2 */
  28         xfs_dablk_t     leafblk;        /* blockno of leaf data v2 */
  29         xfs_dablk_t     freeblk;        /* blockno of free data v2 */
  30 };
  31
  32 /*========================================================================
  33  * Btree searching and modification structure definitions.
  34  *========================================================================*/
  35
  36 /*
  37  * Search comparison results
  38  */
  39 enum xfs_dacmp {
  40         XFS_CMP_DIFFERENT,      /* names are completely different */
  41         XFS_CMP_EXACT,          /* names are exactly the same */
  42         XFS_CMP_CASE            /* names are same but differ in case */
  43 };
  44
  45 /*
  46  * Structure to ease passing around component names.
  47  */
  48 typedef struct xfs_da_args {
  49         struct xfs_da_geometry *geo;    /* da block geometry */
  50         const uint8_t           *name;          /* string (maybe not NULL terminated) */
  51         int             namelen;        /* length of string (maybe no NULL) */
  52         uint8_t         filetype;       /* filetype of inode for directories */
  53         uint8_t         *value;         /* set of bytes (maybe contain NULLs) */
  54         int             valuelen;       /* length of value */
  55         int             flags;          /* argument flags (eg: ATTR_NOCREATE) */
  56         xfs_dahash_t    hashval;        /* hash value of name */
  57         xfs_ino_t       inumber;        /* input/output inode number */
  58         struct xfs_inode *dp;           /* directory inode to manipulate */
  59         struct xfs_trans *trans;        /* current trans (changes over time) */
  60         xfs_extlen_t    total;          /* total blocks needed, for 1st bmap */
  61         int             whichfork;      /* data or attribute fork */
  62         xfs_dablk_t     blkno;          /* blkno of attr leaf of interest */
  63         int             index;          /* index of attr of interest in blk */
  64         xfs_dablk_t     rmtblkno;       /* remote attr value starting blkno */
  65         int             rmtblkcnt;      /* remote attr value block count */
  66         int             rmtvaluelen;    /* remote attr value length in bytes */
  67         xfs_dablk_t     blkno2;         /* blkno of 2nd attr leaf of interest */
  68         int             index2;         /* index of 2nd attr in blk */
  69         xfs_dablk_t     rmtblkno2;      /* remote attr value starting blkno */
  70         int             rmtblkcnt2;     /* remote attr value block count */
  71         int             rmtvaluelen2;   /* remote attr value length in bytes */
  72         int             op_flags;       /* operation flags */
  73         enum xfs_dacmp  cmpresult;      /* name compare result for lookups */
  74 } xfs_da_args_t;
  75
  76 /*
  77  * Operation flags:
  78  */
  79 #define XFS_DA_OP_JUSTCHECK     0x0001  /* check for ok with no space */
  80 #define XFS_DA_OP_RENAME        0x0002  /* this is an atomic rename op */
  81 #define XFS_DA_OP_ADDNAME       0x0004  /* this is an add operation */
  82 #define XFS_DA_OP_OKNOENT       0x0008  /* lookup/add op, ENOENT ok, else die */
  83 #define XFS_DA_OP_CILOOKUP      0x0010  /* lookup to return CI name if found */
  84
  85 #define XFS_DA_OP_FLAGS \
  86         { XFS_DA_OP_JUSTCHECK,  "JUSTCHECK" }, \
  87         { XFS_DA_OP_RENAME,     "RENAME" }, \
  88         { XFS_DA_OP_ADDNAME,    "ADDNAME" }, \
  89         { XFS_DA_OP_OKNOENT,    "OKNOENT" }, \
  90         { XFS_DA_OP_CILOOKUP,   "CILOOKUP" }
  91
  92 /*
  93  * Storage for holding state during Btree searches and split/join ops.
  94  *
  95  * Only need space for 5 intermediate nodes.  With a minimum of 62-way
  96  * fanout to the Btree, we can support over 900 million directory blocks,
  97  * which is slightly more than enough.
  98  */
  99 typedef struct xfs_da_state_blk {
 100         struct xfs_buf  *bp;            /* buffer containing block */
 101         xfs_dablk_t     blkno;          /* filesystem blkno of buffer */
 102         xfs_daddr_t     disk_blkno;     /* on-disk blkno (in BBs) of buffer */
 103         int             index;          /* relevant index into block */
 104         xfs_dahash_t    hashval;        /* last hash value in block */
 105         int             magic;          /* blk's magic number, ie: blk type */
 106 } xfs_da_state_blk_t;
 107
 108 typedef struct xfs_da_state_path {
 109         int                     active;         /* number of active levels */
 110         xfs_da_state_blk_t      blk[XFS_DA_NODE_MAXDEPTH];
 111 } xfs_da_state_path_t;
 112
 113 typedef struct xfs_da_state {
 114         xfs_da_args_t           *args;          /* filename arguments */
 115         struct xfs_mount        *mp;            /* filesystem mount point */
 116         xfs_da_state_path_t     path;           /* search/split paths */
 117         xfs_da_state_path_t     altpath;        /* alternate path for join */
 118         unsigned char           inleaf;         /* insert into 1->lf, 0->splf */
 119         unsigned char           extravalid;     /* T/F: extrablk is in use */
 120         unsigned char           extraafter;     /* T/F: extrablk is after new */
 121         xfs_da_state_blk_t      extrablk;       /* for double-splits on leaves */
 122                                                 /* for dirv2 extrablk is data */
 123 } xfs_da_state_t;
 124
 125 /*
 126  * Utility macros to aid in logging changed structure fields.
 127  */
 128 #define XFS_DA_LOGOFF(BASE, ADDR)       ((char *)(ADDR) - (char *)(BASE))
 129 #define XFS_DA_LOGRANGE(BASE, ADDR, SIZE)       \
 130                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
 131                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)
 132
 133 /*
 134  * Name ops for directory and/or attr name operations
 135  */
 136 struct xfs_nameops {
 137         xfs_dahash_t    (*hashname)(struct xfs_name *);
 138         enum xfs_dacmp  (*compname)(struct xfs_da_args *,
 139                                         const unsigned char *, int);
 140 };
 141
 142
 143 /*========================================================================
 144  * Function prototypes.
 145  *========================================================================*/
 146
 147 /*
 148  * Routines used for growing the Btree.
 149  */
 150 int     xfs_da3_node_create(struct xfs_da_args *args, xfs_dablk_t blkno,
 151                             int level, struct xfs_buf **bpp, int whichfork);
 152 int     xfs_da3_split(xfs_da_state_t *state);
 153
 154 /*
 155  * Routines used for shrinking the Btree.
 156  */
 157 int     xfs_da3_join(xfs_da_state_t *state);
 158 void    xfs_da3_fixhashpath(struct xfs_da_state *state,
 159                             struct xfs_da_state_path *path_to_to_fix);
 160
 161 /*
 162  * Routines used for finding things in the Btree.
 163  */
 164 int     xfs_da3_node_lookup_int(xfs_da_state_t *state, int *result);
 165 int     xfs_da3_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
 166                                          int forward, int release, int *result);
 167 /*
 168  * Utility routines.
 169  */
 170 int     xfs_da3_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
 171                                        xfs_da_state_blk_t *new_blk);
 172 int     xfs_da3_node_read(struct xfs_trans *tp, struct xfs_inode *dp,
 173                          xfs_dablk_t bno, xfs_daddr_t mappedbno,
 174                          struct xfs_buf **bpp, int which_fork);
 175
 176 /*
 177  * Utility routines.
 178  */
 179 int     xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
 180 int     xfs_da_grow_inode_int(struct xfs_da_args *args, xfs_fileoff_t *bno,
 181                               int count);
 182 int     xfs_da_get_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 183                               xfs_dablk_t bno, xfs_daddr_t mappedbno,
 184                               struct xfs_buf **bp, int whichfork);
 185 int     xfs_da_read_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 186                                xfs_dablk_t bno, xfs_daddr_t mappedbno,
 187                                struct xfs_buf **bpp, int whichfork,
 188                                const struct xfs_buf_ops *ops);
 189 int     xfs_da_reada_buf(struct xfs_inode *dp, xfs_dablk_t bno,
 190                                 xfs_daddr_t mapped_bno, int whichfork,
 191                                 const struct xfs_buf_ops *ops);
 192 int     xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
 193                                           struct xfs_buf *dead_buf);
 194
 195 uint xfs_da_hashname(const uint8_t *name_string, int name_length);
 196 enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
 197                                 const unsigned char *name, int len);
 198
 199
 200 xfs_da_state_t *xfs_da_state_alloc(void);
 201 void xfs_da_state_free(xfs_da_state_t *state);
 202
 203 extern struct kmem_zone *xfs_da_state_zone;
 204 extern const struct xfs_nameops xfs_default_nameops;
 205
 206 #endif  /* __XFS_DA_BTREE_H__ */