fs/xfs/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_bmap_free;
  23 struct xfs_inode;
  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  * 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_DIR3_LEAF1_MAGIC    0x3df1  /* magic number: v2 dirlf single blks */
  59 #define XFS_DIR3_LEAFN_MAGIC    0x3dff  /* magic number: v2 dirlf multi blks */
  60
  61 struct xfs_da3_blkinfo {
  62         /*
  63          * the node link manipulation code relies on the fact that the first
  64          * element of this structure is the struct xfs_da_blkinfo so it can
  65          * ignore the differences in the rest of the structures.
  66          */
  67         struct xfs_da_blkinfo   hdr;
  68         __be32                  crc;    /* CRC of block */
  69         __be64                  blkno;  /* first block of the buffer */
  70         __be64                  lsn;    /* sequence number of last write */
  71         uuid_t                  uuid;   /* filesystem we belong to */
  72         __be64                  owner;  /* inode that owns the block */
  73 };
  74
  75 /*
  76  * This is the structure of the root and intermediate nodes in the Btree.
  77  * The leaf nodes are defined above.
  78  *
  79  * Entries are not packed.
  80  *
  81  * Since we have duplicate keys, use a binary search but always follow
  82  * all match in the block, not just the first match found.
  83  */
  84 #define XFS_DA_NODE_MAXDEPTH    5       /* max depth of Btree */
  85
  86 typedef struct xfs_da_node_hdr {
  87         struct xfs_da_blkinfo   info;   /* block type, links, etc. */
  88         __be16                  count; /* count of active entries */
  89         __be16                  __level; /* level above leaves (leaf == 0) */
  90 } xfs_da_node_hdr_t;
  91
  92 struct xfs_da3_node_hdr {
  93         struct xfs_da3_blkinfo  info;   /* block type, links, etc. */
  94         __be16                  count; /* count of active entries */
  95         __be16                  __level; /* level above leaves (leaf == 0) */
  96         __be32                  __pad32;
  97 };
  98
  99 #define XFS_DA3_NODE_CRC_OFF    (offsetof(struct xfs_da3_node_hdr, info.crc))
 100
 101 typedef struct xfs_da_node_entry {
 102         __be32  hashval;        /* hash value for this descendant */
 103         __be32  before;         /* Btree block before this key */
 104 } xfs_da_node_entry_t;
 105
 106 typedef struct xfs_da_intnode {
 107         struct xfs_da_node_hdr  hdr;
 108         struct xfs_da_node_entry __btree[];
 109 } xfs_da_intnode_t;
 110
 111 struct xfs_da3_intnode {
 112         struct xfs_da3_node_hdr hdr;
 113         struct xfs_da_node_entry __btree[];
 114 };
 115
 116 /*
 117  * In-core version of the node header to abstract the differences in the v2 and
 118  * v3 disk format of the headers. Callers need to convert to/from disk format as
 119  * appropriate.
 120  */
 121 struct xfs_da3_icnode_hdr {
 122         __uint32_t      forw;
 123         __uint32_t      back;
 124         __uint16_t      magic;
 125         __uint16_t      count;
 126         __uint16_t      level;
 127 };
 128
 129 extern void xfs_da3_node_hdr_from_disk(struct xfs_da3_icnode_hdr *to,
 130                                        struct xfs_da_intnode *from);
 131 extern void xfs_da3_node_hdr_to_disk(struct xfs_da_intnode *to,
 132                                      struct xfs_da3_icnode_hdr *from);
 133
 134 static inline int
 135 xfs_da3_node_hdr_size(struct xfs_da_intnode *dap)
 136 {
 137         if (dap->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC))
 138                 return sizeof(struct xfs_da3_node_hdr);
 139         return sizeof(struct xfs_da_node_hdr);
 140 }
 141
 142 static inline struct xfs_da_node_entry *
 143 xfs_da3_node_tree_p(struct xfs_da_intnode *dap)
 144 {
 145         if (dap->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC)) {
 146                 struct xfs_da3_intnode *dap3 = (struct xfs_da3_intnode *)dap;
 147                 return dap3->__btree;
 148         }
 149         return dap->__btree;
 150 }
 151
 152 extern void xfs_da3_intnode_from_disk(struct xfs_da3_icnode_hdr *to,
 153                                       struct xfs_da_intnode *from);
 154 extern void xfs_da3_intnode_to_disk(struct xfs_da_intnode *to,
 155                                     struct xfs_da3_icnode_hdr *from);
 156
 157 #define XFS_LBSIZE(mp)  (mp)->m_sb.sb_blocksize
 158
 159 /*========================================================================
 160  * Btree searching and modification structure definitions.
 161  *========================================================================*/
 162
 163 /*
 164  * Search comparison results
 165  */
 166 enum xfs_dacmp {
 167         XFS_CMP_DIFFERENT,      /* names are completely different */
 168         XFS_CMP_EXACT,          /* names are exactly the same */
 169         XFS_CMP_CASE            /* names are same but differ in case */
 170 };
 171
 172 /*
 173  * Structure to ease passing around component names.
 174  */
 175 typedef struct xfs_da_args {
 176         const __uint8_t *name;          /* string (maybe not NULL terminated) */
 177         int             namelen;        /* length of string (maybe no NULL) */
 178         __uint8_t       *value;         /* set of bytes (maybe contain NULLs) */
 179         int             valuelen;       /* length of value */
 180         int             flags;          /* argument flags (eg: ATTR_NOCREATE) */
 181         xfs_dahash_t    hashval;        /* hash value of name */
 182         xfs_ino_t       inumber;        /* input/output inode number */
 183         struct xfs_inode *dp;           /* directory inode to manipulate */
 184         xfs_fsblock_t   *firstblock;    /* ptr to firstblock for bmap calls */
 185         struct xfs_bmap_free *flist;    /* ptr to freelist for bmap_finish */
 186         struct xfs_trans *trans;        /* current trans (changes over time) */
 187         xfs_extlen_t    total;          /* total blocks needed, for 1st bmap */
 188         int             whichfork;      /* data or attribute fork */
 189         xfs_dablk_t     blkno;          /* blkno of attr leaf of interest */
 190         int             index;          /* index of attr of interest in blk */
 191         xfs_dablk_t     rmtblkno;       /* remote attr value starting blkno */
 192         int             rmtblkcnt;      /* remote attr value block count */
 193         xfs_dablk_t     blkno2;         /* blkno of 2nd attr leaf of interest */
 194         int             index2;         /* index of 2nd attr in blk */
 195         xfs_dablk_t     rmtblkno2;      /* remote attr value starting blkno */
 196         int             rmtblkcnt2;     /* remote attr value block count */
 197         int             op_flags;       /* operation flags */
 198         enum xfs_dacmp  cmpresult;      /* name compare result for lookups */
 199 } xfs_da_args_t;
 200
 201 /*
 202  * Operation flags:
 203  */
 204 #define XFS_DA_OP_JUSTCHECK     0x0001  /* check for ok with no space */
 205 #define XFS_DA_OP_RENAME        0x0002  /* this is an atomic rename op */
 206 #define XFS_DA_OP_ADDNAME       0x0004  /* this is an add operation */
 207 #define XFS_DA_OP_OKNOENT       0x0008  /* lookup/add op, ENOENT ok, else die */
 208 #define XFS_DA_OP_CILOOKUP      0x0010  /* lookup to return CI name if found */
 209
 210 #define XFS_DA_OP_FLAGS \
 211         { XFS_DA_OP_JUSTCHECK,  "JUSTCHECK" }, \
 212         { XFS_DA_OP_RENAME,     "RENAME" }, \
 213         { XFS_DA_OP_ADDNAME,    "ADDNAME" }, \
 214         { XFS_DA_OP_OKNOENT,    "OKNOENT" }, \
 215         { XFS_DA_OP_CILOOKUP,   "CILOOKUP" }
 216
 217 /*
 218  * Storage for holding state during Btree searches and split/join ops.
 219  *
 220  * Only need space for 5 intermediate nodes.  With a minimum of 62-way
 221  * fanout to the Btree, we can support over 900 million directory blocks,
 222  * which is slightly more than enough.
 223  */
 224 typedef struct xfs_da_state_blk {
 225         struct xfs_buf  *bp;            /* buffer containing block */
 226         xfs_dablk_t     blkno;          /* filesystem blkno of buffer */
 227         xfs_daddr_t     disk_blkno;     /* on-disk blkno (in BBs) of buffer */
 228         int             index;          /* relevant index into block */
 229         xfs_dahash_t    hashval;        /* last hash value in block */
 230         int             magic;          /* blk's magic number, ie: blk type */
 231 } xfs_da_state_blk_t;
 232
 233 typedef struct xfs_da_state_path {
 234         int                     active;         /* number of active levels */
 235         xfs_da_state_blk_t      blk[XFS_DA_NODE_MAXDEPTH];
 236 } xfs_da_state_path_t;
 237
 238 typedef struct xfs_da_state {
 239         xfs_da_args_t           *args;          /* filename arguments */
 240         struct xfs_mount        *mp;            /* filesystem mount point */
 241         unsigned int            blocksize;      /* logical block size */
 242         unsigned int            node_ents;      /* how many entries in danode */
 243         xfs_da_state_path_t     path;           /* search/split paths */
 244         xfs_da_state_path_t     altpath;        /* alternate path for join */
 245         unsigned char           inleaf;         /* insert into 1->lf, 0->splf */
 246         unsigned char           extravalid;     /* T/F: extrablk is in use */
 247         unsigned char           extraafter;     /* T/F: extrablk is after new */
 248         xfs_da_state_blk_t      extrablk;       /* for double-splits on leaves */
 249                                                 /* for dirv2 extrablk is data */
 250 } xfs_da_state_t;
 251
 252 /*
 253  * Utility macros to aid in logging changed structure fields.
 254  */
 255 #define XFS_DA_LOGOFF(BASE, ADDR)       ((char *)(ADDR) - (char *)(BASE))
 256 #define XFS_DA_LOGRANGE(BASE, ADDR, SIZE)       \
 257                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
 258                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)
 259
 260 /*
 261  * Name ops for directory and/or attr name operations
 262  */
 263 struct xfs_nameops {
 264         xfs_dahash_t    (*hashname)(struct xfs_name *);
 265         enum xfs_dacmp  (*compname)(struct xfs_da_args *,
 266                                         const unsigned char *, int);
 267 };
 268
 269
 270 /*========================================================================
 271  * Function prototypes.
 272  *========================================================================*/
 273
 274 /*
 275  * Routines used for growing the Btree.
 276  */
 277 int     xfs_da3_node_create(struct xfs_da_args *args, xfs_dablk_t blkno,
 278                             int level, struct xfs_buf **bpp, int whichfork);
 279 int     xfs_da3_split(xfs_da_state_t *state);
 280
 281 /*
 282  * Routines used for shrinking the Btree.
 283  */
 284 int     xfs_da3_join(xfs_da_state_t *state);
 285 void    xfs_da3_fixhashpath(struct xfs_da_state *state,
 286                             struct xfs_da_state_path *path_to_to_fix);
 287
 288 /*
 289  * Routines used for finding things in the Btree.
 290  */
 291 int     xfs_da3_node_lookup_int(xfs_da_state_t *state, int *result);
 292 int     xfs_da3_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
 293                                          int forward, int release, int *result);
 294 /*
 295  * Utility routines.
 296  */
 297 int     xfs_da3_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
 298                                        xfs_da_state_blk_t *new_blk);
 299 int     xfs_da3_node_read(struct xfs_trans *tp, struct xfs_inode *dp,
 300                          xfs_dablk_t bno, xfs_daddr_t mappedbno,
 301                          struct xfs_buf **bpp, int which_fork);
 302
 303 /*
 304  * Utility routines.
 305  */
 306 int     xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
 307 int     xfs_da_grow_inode_int(struct xfs_da_args *args, xfs_fileoff_t *bno,
 308                               int count);
 309 int     xfs_da_get_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 310                               xfs_dablk_t bno, xfs_daddr_t mappedbno,
 311                               struct xfs_buf **bp, int whichfork);
 312 int     xfs_da_read_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 313                                xfs_dablk_t bno, xfs_daddr_t mappedbno,
 314                                struct xfs_buf **bpp, int whichfork,
 315                                const struct xfs_buf_ops *ops);
 316 xfs_daddr_t     xfs_da_reada_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 317                                 xfs_dablk_t bno, xfs_daddr_t mapped_bno,
 318                                 int whichfork, const struct xfs_buf_ops *ops);
 319 int     xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
 320                                           struct xfs_buf *dead_buf);
 321
 322 uint xfs_da_hashname(const __uint8_t *name_string, int name_length);
 323 enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
 324                                 const unsigned char *name, int len);
 325
 326
 327 xfs_da_state_t *xfs_da_state_alloc(void);
 328 void xfs_da_state_free(xfs_da_state_t *state);
 329
 330 extern struct kmem_zone *xfs_da_state_zone;
 331 extern const struct xfs_nameops xfs_default_nameops;
 332
 333 #endif  /* __XFS_DA_BTREE_H__ */