linux/fs/xfs/xfs_da_btree.h
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   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
  22struct xfs_bmap_free;
  23struct xfs_inode;
  24struct xfs_trans;
  25struct 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
  42typedef 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 * CRC enabled directory structure types
  51 *
  52 * The headers change size for the additional verification information, but
  53 * otherwise the tree layouts and contents are unchanged. Hence the da btree
  54 * code can use the struct xfs_da_blkinfo for manipulating the tree links and
  55 * magic numbers without modification for both v2 and v3 nodes.
  56 */
  57#define XFS_DA3_NODE_MAGIC      0x3ebe  /* magic number: non-leaf blocks */
  58#define XFS_ATTR3_LEAF_MAGIC    0x3bee  /* magic number: attribute leaf blks */
  59#define XFS_DIR3_LEAF1_MAGIC    0x3df1  /* magic number: v2 dirlf single blks */
  60#define XFS_DIR3_LEAFN_MAGIC    0x3dff  /* magic number: v2 dirlf multi blks */
  61
  62struct xfs_da3_blkinfo {
  63        /*
  64         * the node link manipulation code relies on the fact that the first
  65         * element of this structure is the struct xfs_da_blkinfo so it can
  66         * ignore the differences in the rest of the structures.
  67         */
  68        struct xfs_da_blkinfo   hdr;
  69        __be32                  crc;    /* CRC of block */
  70        __be64                  blkno;  /* first block of the buffer */
  71        __be64                  lsn;    /* sequence number of last write */
  72        uuid_t                  uuid;   /* filesystem we belong to */
  73        __be64                  owner;  /* inode that owns the block */
  74};
  75
  76/*
  77 * This is the structure of the root and intermediate nodes in the Btree.
  78 * The leaf nodes are defined above.
  79 *
  80 * Entries are not packed.
  81 *
  82 * Since we have duplicate keys, use a binary search but always follow
  83 * all match in the block, not just the first match found.
  84 */
  85#define XFS_DA_NODE_MAXDEPTH    5       /* max depth of Btree */
  86
  87typedef struct xfs_da_node_hdr {
  88        struct xfs_da_blkinfo   info;   /* block type, links, etc. */
  89        __be16                  __count; /* count of active entries */
  90        __be16                  __level; /* level above leaves (leaf == 0) */
  91} xfs_da_node_hdr_t;
  92
  93struct xfs_da3_node_hdr {
  94        struct xfs_da3_blkinfo  info;   /* block type, links, etc. */
  95        __be16                  __count; /* count of active entries */
  96        __be16                  __level; /* level above leaves (leaf == 0) */
  97        __be32                  __pad32;
  98};
  99
 100#define XFS_DA3_NODE_CRC_OFF    (offsetof(struct xfs_da3_node_hdr, info.crc))
 101
 102typedef struct xfs_da_node_entry {
 103        __be32  hashval;        /* hash value for this descendant */
 104        __be32  before;         /* Btree block before this key */
 105} xfs_da_node_entry_t;
 106
 107typedef struct xfs_da_intnode {
 108        struct xfs_da_node_hdr  hdr;
 109        struct xfs_da_node_entry __btree[];
 110} xfs_da_intnode_t;
 111
 112struct xfs_da3_intnode {
 113        struct xfs_da3_node_hdr hdr;
 114        struct xfs_da_node_entry __btree[];
 115};
 116
 117/*
 118 * In-core version of the node header to abstract the differences in the v2 and
 119 * v3 disk format of the headers. Callers need to convert to/from disk format as
 120 * appropriate.
 121 */
 122struct xfs_da3_icnode_hdr {
 123        __uint32_t      forw;
 124        __uint32_t      back;
 125        __uint16_t      magic;
 126        __uint16_t      count;
 127        __uint16_t      level;
 128};
 129
 130extern void xfs_da3_node_hdr_from_disk(struct xfs_da3_icnode_hdr *to,
 131                                       struct xfs_da_intnode *from);
 132extern void xfs_da3_node_hdr_to_disk(struct xfs_da_intnode *to,
 133                                     struct xfs_da3_icnode_hdr *from);
 134
 135static inline int
 136xfs_da3_node_hdr_size(struct xfs_da_intnode *dap)
 137{
 138        if (dap->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC))
 139                return sizeof(struct xfs_da3_node_hdr);
 140        return sizeof(struct xfs_da_node_hdr);
 141}
 142
 143static inline struct xfs_da_node_entry *
 144xfs_da3_node_tree_p(struct xfs_da_intnode *dap)
 145{
 146        if (dap->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC)) {
 147                struct xfs_da3_intnode *dap3 = (struct xfs_da3_intnode *)dap;
 148                return dap3->__btree;
 149        }
 150        return dap->__btree;
 151}
 152
 153extern void xfs_da3_intnode_from_disk(struct xfs_da3_icnode_hdr *to,
 154                                      struct xfs_da_intnode *from);
 155extern void xfs_da3_intnode_to_disk(struct xfs_da_intnode *to,
 156                                    struct xfs_da3_icnode_hdr *from);
 157
 158#define XFS_LBSIZE(mp)  (mp)->m_sb.sb_blocksize
 159
 160/*========================================================================
 161 * Btree searching and modification structure definitions.
 162 *========================================================================*/
 163
 164/*
 165 * Search comparison results
 166 */
 167enum xfs_dacmp {
 168        XFS_CMP_DIFFERENT,      /* names are completely different */
 169        XFS_CMP_EXACT,          /* names are exactly the same */
 170        XFS_CMP_CASE            /* names are same but differ in case */
 171};
 172
 173/*
 174 * Structure to ease passing around component names.
 175 */
 176typedef struct xfs_da_args {
 177        const __uint8_t *name;          /* string (maybe not NULL terminated) */
 178        int             namelen;        /* length of string (maybe no NULL) */
 179        __uint8_t       *value;         /* set of bytes (maybe contain NULLs) */
 180        int             valuelen;       /* length of value */
 181        int             flags;          /* argument flags (eg: ATTR_NOCREATE) */
 182        xfs_dahash_t    hashval;        /* hash value of name */
 183        xfs_ino_t       inumber;        /* input/output inode number */
 184        struct xfs_inode *dp;           /* directory inode to manipulate */
 185        xfs_fsblock_t   *firstblock;    /* ptr to firstblock for bmap calls */
 186        struct xfs_bmap_free *flist;    /* ptr to freelist for bmap_finish */
 187        struct xfs_trans *trans;        /* current trans (changes over time) */
 188        xfs_extlen_t    total;          /* total blocks needed, for 1st bmap */
 189        int             whichfork;      /* data or attribute fork */
 190        xfs_dablk_t     blkno;          /* blkno of attr leaf of interest */
 191        int             index;          /* index of attr of interest in blk */
 192        xfs_dablk_t     rmtblkno;       /* remote attr value starting blkno */
 193        int             rmtblkcnt;      /* remote attr value block count */
 194        xfs_dablk_t     blkno2;         /* blkno of 2nd attr leaf of interest */
 195        int             index2;         /* index of 2nd attr in blk */
 196        xfs_dablk_t     rmtblkno2;      /* remote attr value starting blkno */
 197        int             rmtblkcnt2;     /* remote attr value block count */
 198        int             op_flags;       /* operation flags */
 199        enum xfs_dacmp  cmpresult;      /* name compare result for lookups */
 200} xfs_da_args_t;
 201
 202/*
 203 * Operation flags:
 204 */
 205#define XFS_DA_OP_JUSTCHECK     0x0001  /* check for ok with no space */
 206#define XFS_DA_OP_RENAME        0x0002  /* this is an atomic rename op */
 207#define XFS_DA_OP_ADDNAME       0x0004  /* this is an add operation */
 208#define XFS_DA_OP_OKNOENT       0x0008  /* lookup/add op, ENOENT ok, else die */
 209#define XFS_DA_OP_CILOOKUP      0x0010  /* lookup to return CI name if found */
 210
 211#define XFS_DA_OP_FLAGS \
 212        { XFS_DA_OP_JUSTCHECK,  "JUSTCHECK" }, \
 213        { XFS_DA_OP_RENAME,     "RENAME" }, \
 214        { XFS_DA_OP_ADDNAME,    "ADDNAME" }, \
 215        { XFS_DA_OP_OKNOENT,    "OKNOENT" }, \
 216        { XFS_DA_OP_CILOOKUP,   "CILOOKUP" }
 217
 218/*
 219 * Storage for holding state during Btree searches and split/join ops.
 220 *
 221 * Only need space for 5 intermediate nodes.  With a minimum of 62-way
 222 * fanout to the Btree, we can support over 900 million directory blocks,
 223 * which is slightly more than enough.
 224 */
 225typedef struct xfs_da_state_blk {
 226        struct xfs_buf  *bp;            /* buffer containing block */
 227        xfs_dablk_t     blkno;          /* filesystem blkno of buffer */
 228        xfs_daddr_t     disk_blkno;     /* on-disk blkno (in BBs) of buffer */
 229        int             index;          /* relevant index into block */
 230        xfs_dahash_t    hashval;        /* last hash value in block */
 231        int             magic;          /* blk's magic number, ie: blk type */
 232} xfs_da_state_blk_t;
 233
 234typedef struct xfs_da_state_path {
 235        int                     active;         /* number of active levels */
 236        xfs_da_state_blk_t      blk[XFS_DA_NODE_MAXDEPTH];
 237} xfs_da_state_path_t;
 238
 239typedef struct xfs_da_state {
 240        xfs_da_args_t           *args;          /* filename arguments */
 241        struct xfs_mount        *mp;            /* filesystem mount point */
 242        unsigned int            blocksize;      /* logical block size */
 243        unsigned int            node_ents;      /* how many entries in danode */
 244        xfs_da_state_path_t     path;           /* search/split paths */
 245        xfs_da_state_path_t     altpath;        /* alternate path for join */
 246        unsigned char           inleaf;         /* insert into 1->lf, 0->splf */
 247        unsigned char           extravalid;     /* T/F: extrablk is in use */
 248        unsigned char           extraafter;     /* T/F: extrablk is after new */
 249        xfs_da_state_blk_t      extrablk;       /* for double-splits on leaves */
 250                                                /* for dirv2 extrablk is data */
 251} xfs_da_state_t;
 252
 253/*
 254 * Utility macros to aid in logging changed structure fields.
 255 */
 256#define XFS_DA_LOGOFF(BASE, ADDR)       ((char *)(ADDR) - (char *)(BASE))
 257#define XFS_DA_LOGRANGE(BASE, ADDR, SIZE)       \
 258                (uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
 259                (uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)
 260
 261/*
 262 * Name ops for directory and/or attr name operations
 263 */
 264struct xfs_nameops {
 265        xfs_dahash_t    (*hashname)(struct xfs_name *);
 266        enum xfs_dacmp  (*compname)(struct xfs_da_args *,
 267                                        const unsigned char *, int);
 268};
 269
 270
 271/*========================================================================
 272 * Function prototypes.
 273 *========================================================================*/
 274
 275/*
 276 * Routines used for growing the Btree.
 277 */
 278int     xfs_da3_node_create(struct xfs_da_args *args, xfs_dablk_t blkno,
 279                            int level, struct xfs_buf **bpp, int whichfork);
 280int     xfs_da3_split(xfs_da_state_t *state);
 281
 282/*
 283 * Routines used for shrinking the Btree.
 284 */
 285int     xfs_da3_join(xfs_da_state_t *state);
 286void    xfs_da3_fixhashpath(struct xfs_da_state *state,
 287                            struct xfs_da_state_path *path_to_to_fix);
 288
 289/*
 290 * Routines used for finding things in the Btree.
 291 */
 292int     xfs_da3_node_lookup_int(xfs_da_state_t *state, int *result);
 293int     xfs_da3_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
 294                                         int forward, int release, int *result);
 295/*
 296 * Utility routines.
 297 */
 298int     xfs_da3_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
 299                                       xfs_da_state_blk_t *new_blk);
 300int     xfs_da3_node_read(struct xfs_trans *tp, struct xfs_inode *dp,
 301                         xfs_dablk_t bno, xfs_daddr_t mappedbno,
 302                         struct xfs_buf **bpp, int which_fork);
 303
 304extern const struct xfs_buf_ops xfs_da3_node_buf_ops;
 305
 306/*
 307 * Utility routines.
 308 */
 309int     xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
 310int     xfs_da_grow_inode_int(struct xfs_da_args *args, xfs_fileoff_t *bno,
 311                              int count);
 312int     xfs_da_get_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 313                              xfs_dablk_t bno, xfs_daddr_t mappedbno,
 314                              struct xfs_buf **bp, int whichfork);
 315int     xfs_da_read_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 316                               xfs_dablk_t bno, xfs_daddr_t mappedbno,
 317                               struct xfs_buf **bpp, int whichfork,
 318                               const struct xfs_buf_ops *ops);
 319xfs_daddr_t     xfs_da_reada_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 320                                xfs_dablk_t bno, xfs_daddr_t mapped_bno,
 321                                int whichfork, const struct xfs_buf_ops *ops);
 322int     xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
 323                                          struct xfs_buf *dead_buf);
 324
 325uint xfs_da_hashname(const __uint8_t *name_string, int name_length);
 326enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
 327                                const unsigned char *name, int len);
 328
 329
 330xfs_da_state_t *xfs_da_state_alloc(void);
 331void xfs_da_state_free(xfs_da_state_t *state);
 332
 333extern struct kmem_zone *xfs_da_state_zone;
 334extern const struct xfs_nameops xfs_default_nameops;
 335
 336#endif  /* __XFS_DA_BTREE_H__ */
 337
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