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_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
  62 struct 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
  87 typedef 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
  93 struct 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
 102 typedef 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
 107 typedef struct xfs_da_intnode {
 108         struct xfs_da_node_hdr  hdr;
 109         struct xfs_da_node_entry __btree[];
 110 } xfs_da_intnode_t;
 111
 112 struct 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  */
 122 struct 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
 130 extern void xfs_da3_node_hdr_from_disk(struct xfs_da3_icnode_hdr *to,
 131                                        struct xfs_da_intnode *from);
 132 extern void xfs_da3_node_hdr_to_disk(struct xfs_da_intnode *to,
 133                                      struct xfs_da3_icnode_hdr *from);
 134
 135 static inline int
 136 __xfs_da3_node_hdr_size(bool v3)
 137 {
 138         if (v3)
 139                 return sizeof(struct xfs_da3_node_hdr);
 140         return sizeof(struct xfs_da_node_hdr);
 141 }
 142 static inline int
 143 xfs_da3_node_hdr_size(struct xfs_da_intnode *dap)
 144 {
 145         bool    v3 = dap->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC);
 146
 147         return __xfs_da3_node_hdr_size(v3);
 148 }
 149
 150 static inline struct xfs_da_node_entry *
 151 xfs_da3_node_tree_p(struct xfs_da_intnode *dap)
 152 {
 153         if (dap->hdr.info.magic == cpu_to_be16(XFS_DA3_NODE_MAGIC)) {
 154                 struct xfs_da3_intnode *dap3 = (struct xfs_da3_intnode *)dap;
 155                 return dap3->__btree;
 156         }
 157         return dap->__btree;
 158 }
 159
 160 extern void xfs_da3_intnode_from_disk(struct xfs_da3_icnode_hdr *to,
 161                                       struct xfs_da_intnode *from);
 162 extern void xfs_da3_intnode_to_disk(struct xfs_da_intnode *to,
 163                                     struct xfs_da3_icnode_hdr *from);
 164
 165 #define XFS_LBSIZE(mp)  (mp)->m_sb.sb_blocksize
 166
 167 /*========================================================================
 168  * Btree searching and modification structure definitions.
 169  *========================================================================*/
 170
 171 /*
 172  * Search comparison results
 173  */
 174 enum xfs_dacmp {
 175         XFS_CMP_DIFFERENT,      /* names are completely different */
 176         XFS_CMP_EXACT,          /* names are exactly the same */
 177         XFS_CMP_CASE            /* names are same but differ in case */
 178 };
 179
 180 /*
 181  * Structure to ease passing around component names.
 182  */
 183 typedef struct xfs_da_args {
 184         const __uint8_t *name;          /* string (maybe not NULL terminated) */
 185         int             namelen;        /* length of string (maybe no NULL) */
 186         __uint8_t       filetype;       /* filetype of inode for directories */
 187         __uint8_t       *value;         /* set of bytes (maybe contain NULLs) */
 188         int             valuelen;       /* length of value */
 189         int             flags;          /* argument flags (eg: ATTR_NOCREATE) */
 190         xfs_dahash_t    hashval;        /* hash value of name */
 191         xfs_ino_t       inumber;        /* input/output inode number */
 192         struct xfs_inode *dp;           /* directory inode to manipulate */
 193         xfs_fsblock_t   *firstblock;    /* ptr to firstblock for bmap calls */
 194         struct xfs_bmap_free *flist;    /* ptr to freelist for bmap_finish */
 195         struct xfs_trans *trans;        /* current trans (changes over time) */
 196         xfs_extlen_t    total;          /* total blocks needed, for 1st bmap */
 197         int             whichfork;      /* data or attribute fork */
 198         xfs_dablk_t     blkno;          /* blkno of attr leaf of interest */
 199         int             index;          /* index of attr of interest in blk */
 200         xfs_dablk_t     rmtblkno;       /* remote attr value starting blkno */
 201         int             rmtblkcnt;      /* remote attr value block count */
 202         xfs_dablk_t     blkno2;         /* blkno of 2nd attr leaf of interest */
 203         int             index2;         /* index of 2nd attr in blk */
 204         xfs_dablk_t     rmtblkno2;      /* remote attr value starting blkno */
 205         int             rmtblkcnt2;     /* remote attr value block count */
 206         int             op_flags;       /* operation flags */
 207         enum xfs_dacmp  cmpresult;      /* name compare result for lookups */
 208 } xfs_da_args_t;
 209
 210 /*
 211  * Operation flags:
 212  */
 213 #define XFS_DA_OP_JUSTCHECK     0x0001  /* check for ok with no space */
 214 #define XFS_DA_OP_RENAME        0x0002  /* this is an atomic rename op */
 215 #define XFS_DA_OP_ADDNAME       0x0004  /* this is an add operation */
 216 #define XFS_DA_OP_OKNOENT       0x0008  /* lookup/add op, ENOENT ok, else die */
 217 #define XFS_DA_OP_CILOOKUP      0x0010  /* lookup to return CI name if found */
 218
 219 #define XFS_DA_OP_FLAGS \
 220         { XFS_DA_OP_JUSTCHECK,  "JUSTCHECK" }, \
 221         { XFS_DA_OP_RENAME,     "RENAME" }, \
 222         { XFS_DA_OP_ADDNAME,    "ADDNAME" }, \
 223         { XFS_DA_OP_OKNOENT,    "OKNOENT" }, \
 224         { XFS_DA_OP_CILOOKUP,   "CILOOKUP" }
 225
 226 /*
 227  * Storage for holding state during Btree searches and split/join ops.
 228  *
 229  * Only need space for 5 intermediate nodes.  With a minimum of 62-way
 230  * fanout to the Btree, we can support over 900 million directory blocks,
 231  * which is slightly more than enough.
 232  */
 233 typedef struct xfs_da_state_blk {
 234         struct xfs_buf  *bp;            /* buffer containing block */
 235         xfs_dablk_t     blkno;          /* filesystem blkno of buffer */
 236         xfs_daddr_t     disk_blkno;     /* on-disk blkno (in BBs) of buffer */
 237         int             index;          /* relevant index into block */
 238         xfs_dahash_t    hashval;        /* last hash value in block */
 239         int             magic;          /* blk's magic number, ie: blk type */
 240 } xfs_da_state_blk_t;
 241
 242 typedef struct xfs_da_state_path {
 243         int                     active;         /* number of active levels */
 244         xfs_da_state_blk_t      blk[XFS_DA_NODE_MAXDEPTH];
 245 } xfs_da_state_path_t;
 246
 247 typedef struct xfs_da_state {
 248         xfs_da_args_t           *args;          /* filename arguments */
 249         struct xfs_mount        *mp;            /* filesystem mount point */
 250         unsigned int            blocksize;      /* logical block size */
 251         unsigned int            node_ents;      /* how many entries in danode */
 252         xfs_da_state_path_t     path;           /* search/split paths */
 253         xfs_da_state_path_t     altpath;        /* alternate path for join */
 254         unsigned char           inleaf;         /* insert into 1->lf, 0->splf */
 255         unsigned char           extravalid;     /* T/F: extrablk is in use */
 256         unsigned char           extraafter;     /* T/F: extrablk is after new */
 257         xfs_da_state_blk_t      extrablk;       /* for double-splits on leaves */
 258                                                 /* for dirv2 extrablk is data */
 259 } xfs_da_state_t;
 260
 261 /*
 262  * Utility macros to aid in logging changed structure fields.
 263  */
 264 #define XFS_DA_LOGOFF(BASE, ADDR)       ((char *)(ADDR) - (char *)(BASE))
 265 #define XFS_DA_LOGRANGE(BASE, ADDR, SIZE)       \
 266                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)), \
 267                 (uint)(XFS_DA_LOGOFF(BASE, ADDR)+(SIZE)-1)
 268
 269 /*
 270  * Name ops for directory and/or attr name operations
 271  */
 272 struct xfs_nameops {
 273         xfs_dahash_t    (*hashname)(struct xfs_name *);
 274         enum xfs_dacmp  (*compname)(struct xfs_da_args *,
 275                                         const unsigned char *, int);
 276 };
 277
 278
 279 /*========================================================================
 280  * Function prototypes.
 281  *========================================================================*/
 282
 283 /*
 284  * Routines used for growing the Btree.
 285  */
 286 int     xfs_da3_node_create(struct xfs_da_args *args, xfs_dablk_t blkno,
 287                             int level, struct xfs_buf **bpp, int whichfork);
 288 int     xfs_da3_split(xfs_da_state_t *state);
 289
 290 /*
 291  * Routines used for shrinking the Btree.
 292  */
 293 int     xfs_da3_join(xfs_da_state_t *state);
 294 void    xfs_da3_fixhashpath(struct xfs_da_state *state,
 295                             struct xfs_da_state_path *path_to_to_fix);
 296
 297 /*
 298  * Routines used for finding things in the Btree.
 299  */
 300 int     xfs_da3_node_lookup_int(xfs_da_state_t *state, int *result);
 301 int     xfs_da3_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
 302                                          int forward, int release, int *result);
 303 /*
 304  * Utility routines.
 305  */
 306 int     xfs_da3_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
 307                                        xfs_da_state_blk_t *new_blk);
 308 int     xfs_da3_node_read(struct xfs_trans *tp, struct xfs_inode *dp,
 309                          xfs_dablk_t bno, xfs_daddr_t mappedbno,
 310                          struct xfs_buf **bpp, int which_fork);
 311
 312 extern const struct xfs_buf_ops xfs_da3_node_buf_ops;
 313
 314 /*
 315  * Utility routines.
 316  */
 317 int     xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
 318 int     xfs_da_grow_inode_int(struct xfs_da_args *args, xfs_fileoff_t *bno,
 319                               int count);
 320 int     xfs_da_get_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 321                               xfs_dablk_t bno, xfs_daddr_t mappedbno,
 322                               struct xfs_buf **bp, int whichfork);
 323 int     xfs_da_read_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 324                                xfs_dablk_t bno, xfs_daddr_t mappedbno,
 325                                struct xfs_buf **bpp, int whichfork,
 326                                const struct xfs_buf_ops *ops);
 327 xfs_daddr_t     xfs_da_reada_buf(struct xfs_trans *trans, struct xfs_inode *dp,
 328                                 xfs_dablk_t bno, xfs_daddr_t mapped_bno,
 329                                 int whichfork, const struct xfs_buf_ops *ops);
 330 int     xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
 331                                           struct xfs_buf *dead_buf);
 332
 333 uint xfs_da_hashname(const __uint8_t *name_string, int name_length);
 334 enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
 335                                 const unsigned char *name, int len);
 336
 337
 338 xfs_da_state_t *xfs_da_state_alloc(void);
 339 void xfs_da_state_free(xfs_da_state_t *state);
 340
 341 extern struct kmem_zone *xfs_da_state_zone;
 342 extern const struct xfs_nameops xfs_default_nameops;
 343
 344 #endif  /* __XFS_DA_BTREE_H__ */