fs/xfs/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
  14 /*
  15  * Directory/attribute geometry information. There will be one of these for each
  16  * data fork type, and it will be passed around via the xfs_da_args. Global
  17  * structures will be attached to the xfs_mount.
  18  */
  19 struct xfs_da_geometry {
  20         unsigned int    blksize;        /* da block size in bytes */
  21         unsigned int    fsbcount;       /* da block size in filesystem blocks */
  22         uint8_t         fsblog;         /* log2 of _filesystem_ block size */
  23         uint8_t         blklog;         /* log2 of da block size */
  24         unsigned int    node_hdr_size;  /* danode header size in bytes */
  25         unsigned int    node_ents;      /* # of entries in a danode */
  26         unsigned int    magicpct;       /* 37% of block size in bytes */
  27         xfs_dablk_t     datablk;        /* blockno of dir data v2 */
  28         unsigned int    leaf_hdr_size;  /* dir2 leaf header size */
  29         unsigned int    leaf_max_ents;  /* # of entries in dir2 leaf */
  30         xfs_dablk_t     leafblk;        /* blockno of leaf data v2 */
  31         unsigned int    free_hdr_size;  /* dir2 free header size */
  32         unsigned int    free_max_bests; /* # of bests entries in dir2 free */
  33         xfs_dablk_t     freeblk;        /* blockno of free data v2 */
  34
  35         xfs_dir2_data_aoff_t data_first_offset;
  36         size_t          data_entry_offset;
  37 };
  38
  39 /*========================================================================
  40  * Btree searching and modification structure definitions.
  41  *========================================================================*/
  42
  43 /*
  44  * Search comparison results
  45  */
  46 enum xfs_dacmp {
  47         XFS_CMP_DIFFERENT,      /* names are completely different */
  48         XFS_CMP_EXACT,          /* names are exactly the same */
  49         XFS_CMP_CASE            /* names are same but differ in case */
  50 };
  51
  52 /*
  53  * Structure to ease passing around component names.
  54  */
  55 typedef struct xfs_da_args {
  56         struct xfs_da_geometry *geo;    /* da block geometry */
  57         const uint8_t           *name;          /* string (maybe not NULL terminated) */
  58         int             namelen;        /* length of string (maybe no NULL) */
  59         uint8_t         filetype;       /* filetype of inode for directories */
  60         uint8_t         *value;         /* set of bytes (maybe contain NULLs) */
  61         int             valuelen;       /* length of value */
  62         int             flags;          /* argument flags (eg: ATTR_NOCREATE) */
  63         xfs_dahash_t    hashval;        /* hash value of name */
  64         xfs_ino_t       inumber;        /* input/output inode number */
  65         struct xfs_inode *dp;           /* directory inode to manipulate */
  66         struct xfs_trans *trans;        /* current trans (changes over time) */
  67         xfs_extlen_t    total;          /* total blocks needed, for 1st bmap */
  68         int             whichfork;      /* data or attribute fork */
  69         xfs_dablk_t     blkno;          /* blkno of attr leaf of interest */
  70         int             index;          /* index of attr of interest in blk */
  71         xfs_dablk_t     rmtblkno;       /* remote attr value starting blkno */
  72         int             rmtblkcnt;      /* remote attr value block count */
  73         int             rmtvaluelen;    /* remote attr value length in bytes */
  74         xfs_dablk_t     blkno2;         /* blkno of 2nd attr leaf of interest */
  75         int             index2;         /* index of 2nd attr in blk */
  76         xfs_dablk_t     rmtblkno2;      /* remote attr value starting blkno */
  77         int             rmtblkcnt2;     /* remote attr value block count */
  78         int             rmtvaluelen2;   /* remote attr value length in bytes */
  79         int             op_flags;       /* operation flags */
  80         enum xfs_dacmp  cmpresult;      /* name compare result for lookups */
  81 } xfs_da_args_t;
  82
  83 /*
  84  * Operation flags:
  85  */
  86 #define XFS_DA_OP_JUSTCHECK     0x0001  /* check for ok with no space */
  87 #define XFS_DA_OP_RENAME        0x0002  /* this is an atomic rename op */
  88 #define XFS_DA_OP_ADDNAME       0x0004  /* this is an add operation */
  89 #define XFS_DA_OP_OKNOENT       0x0008  /* lookup/add op, ENOENT ok, else die */
  90 #define XFS_DA_OP_CILOOKUP      0x0010  /* lookup to return CI name if found */
  91 #define XFS_DA_OP_ALLOCVAL      0x0020  /* lookup to alloc buffer if found  */
  92 #define XFS_DA_OP_INCOMPLETE    0x0040  /* lookup INCOMPLETE attr keys */
  93
  94 #define XFS_DA_OP_FLAGS \
  95         { XFS_DA_OP_JUSTCHECK,  "JUSTCHECK" }, \
  96         { XFS_DA_OP_RENAME,     "RENAME" }, \
  97         { XFS_DA_OP_ADDNAME,    "ADDNAME" }, \
  98         { XFS_DA_OP_OKNOENT,    "OKNOENT" }, \
  99         { XFS_DA_OP_CILOOKUP,   "CILOOKUP" }, \
 100         { XFS_DA_OP_ALLOCVAL,   "ALLOCVAL" }, \
 101         { XFS_DA_OP_INCOMPLETE, "INCOMPLETE" }
 102
 103 /*
 104  * Storage for holding state during Btree searches and split/join ops.
 105  *
 106  * Only need space for 5 intermediate nodes.  With a minimum of 62-way
 107  * fanout to the Btree, we can support over 900 million directory blocks,
 108  * which is slightly more than enough.
 109  */
 110 typedef struct xfs_da_state_blk {
 111         struct xfs_buf  *bp;            /* buffer containing block */
 112         xfs_dablk_t     blkno;          /* filesystem blkno of buffer */
 113         xfs_daddr_t     disk_blkno;     /* on-disk blkno (in BBs) of buffer */
 114         int             index;          /* relevant index into block */
 115         xfs_dahash_t    hashval;        /* last hash value in block */
 116         int             magic;          /* blk's magic number, ie: blk type */
 117 } xfs_da_state_blk_t;
 118
 119 typedef struct xfs_da_state_path {
 120         int                     active;         /* number of active levels */
 121         xfs_da_state_blk_t      blk[XFS_DA_NODE_MAXDEPTH];
 122 } xfs_da_state_path_t;
 123
 124 typedef struct xfs_da_state {
 125         xfs_da_args_t           *args;          /* filename arguments */
 126         struct xfs_mount        *mp;            /* filesystem mount point */
 127         xfs_da_state_path_t     path;           /* search/split paths */
 128         xfs_da_state_path_t     altpath;        /* alternate path for join */
 129         unsigned char           inleaf;         /* insert into 1->lf, 0->splf */
 130         unsigned char           extravalid;     /* T/F: extrablk is in use */
 131         unsigned char           extraafter;     /* T/F: extrablk is after new */
 132         xfs_da_state_blk_t      extrablk;       /* for double-splits on leaves */
 133                                                 /* for dirv2 extrablk is data */
 134 } xfs_da_state_t;
 135
 136 /*
 137  * In-core version of the node header to abstract the differences in the v2 and
 138  * v3 disk format of the headers. Callers need to convert to/from disk format as
 139  * appropriate.
 140  */
 141 struct xfs_da3_icnode_hdr {
 142         uint32_t                forw;
 143         uint32_t                back;
 144         uint16_t                magic;
 145         uint16_t                count;
 146         uint16_t                level;
 147
 148         /*
 149          * Pointer to the on-disk format entries, which are behind the
 150          * variable size (v4 vs v5) header in the on-disk block.
 151          */
 152         struct xfs_da_node_entry *btree;
 153 };
 154
 155 /*
 156  * Utility macros to aid in logging changed structure fields.
 157  */
 158 #define XFS_DA_LOGOFF(BASE, ADDR)       ((char *)(ADDR) - (char *)(BASE))
 159 #define XFS_DA_LOGRANGE(BASE, ADDR, SIZE)       \
 160                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
 161                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)
 162
 163 /*========================================================================
 164  * Function prototypes.
 165  *========================================================================*/
 166
 167 /*
 168  * Routines used for growing the Btree.
 169  */
 170 int     xfs_da3_node_create(struct xfs_da_args *args, xfs_dablk_t blkno,
 171                             int level, struct xfs_buf **bpp, int whichfork);
 172 int     xfs_da3_split(xfs_da_state_t *state);
 173
 174 /*
 175  * Routines used for shrinking the Btree.
 176  */
 177 int     xfs_da3_join(xfs_da_state_t *state);
 178 void    xfs_da3_fixhashpath(struct xfs_da_state *state,
 179                             struct xfs_da_state_path *path_to_to_fix);
 180
 181 /*
 182  * Routines used for finding things in the Btree.
 183  */
 184 int     xfs_da3_node_lookup_int(xfs_da_state_t *state, int *result);
 185 int     xfs_da3_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
 186                                          int forward, int release, int *result);
 187 /*
 188  * Utility routines.
 189  */
 190 int     xfs_da3_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
 191                                        xfs_da_state_blk_t *new_blk);
 192 int     xfs_da3_node_read(struct xfs_trans *tp, struct xfs_inode *dp,
 193                         xfs_dablk_t bno, struct xfs_buf **bpp, int whichfork);
 194 int     xfs_da3_node_read_mapped(struct xfs_trans *tp, struct xfs_inode *dp,
 195                         xfs_daddr_t mappedbno, struct xfs_buf **bpp,
 196                         int whichfork);
 197
 198 /*
 199  * Utility routines.
 200  */
 201
 202 #define XFS_DABUF_MAP_HOLE_OK   (1 << 0)
 203
 204 int     xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
 205 int     xfs_da_grow_inode_int(struct xfs_da_args *args, xfs_fileoff_t *bno,
 206                               int count);
 207 int     xfs_da_get_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 208                 xfs_dablk_t bno, struct xfs_buf **bp, int whichfork);
 209 int     xfs_da_read_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 210                 xfs_dablk_t bno, unsigned int flags, struct xfs_buf **bpp,
 211                 int whichfork, const struct xfs_buf_ops *ops);
 212 int     xfs_da_reada_buf(struct xfs_inode *dp, xfs_dablk_t bno,
 213                 unsigned int flags, int whichfork,
 214                 const struct xfs_buf_ops *ops);
 215 int     xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
 216                                           struct xfs_buf *dead_buf);
 217
 218 uint xfs_da_hashname(const uint8_t *name_string, int name_length);
 219 enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
 220                                 const unsigned char *name, int len);
 221
 222
 223 xfs_da_state_t *xfs_da_state_alloc(void);
 224 void xfs_da_state_free(xfs_da_state_t *state);
 225
 226 void    xfs_da3_node_hdr_from_disk(struct xfs_mount *mp,
 227                 struct xfs_da3_icnode_hdr *to, struct xfs_da_intnode *from);
 228 void    xfs_da3_node_hdr_to_disk(struct xfs_mount *mp,
 229                 struct xfs_da_intnode *to, struct xfs_da3_icnode_hdr *from);
 230
 231 extern struct kmem_zone *xfs_da_state_zone;
 232
 233 #endif  /* __XFS_DA_BTREE_H__ */