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(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
 143 static inline struct xfs_da_node_entry *
 144 xfs_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
 153 extern void xfs_da3_intnode_from_disk(struct xfs_da3_icnode_hdr *to,
 154                                       struct xfs_da_intnode *from);
 155 extern 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  */
 167 enum 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  */
 176 typedef 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  */
 225 typedef 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
 234 typedef 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
 239 typedef 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  */
 264 struct 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  */
 278 int     xfs_da3_node_create(struct xfs_da_args *args, xfs_dablk_t blkno,
 279                             int level, struct xfs_buf **bpp, int whichfork);
 280 int     xfs_da3_split(xfs_da_state_t *state);
 281
 282 /*
 283  * Routines used for shrinking the Btree.
 284  */
 285 int     xfs_da3_join(xfs_da_state_t *state);
 286 void    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  */
 292 int     xfs_da3_node_lookup_int(xfs_da_state_t *state, int *result);
 293 int     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  */
 298 int     xfs_da3_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
 299                                        xfs_da_state_blk_t *new_blk);
 300 int     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
 304 extern const struct xfs_buf_ops xfs_da3_node_buf_ops;
 305
 306 /*
 307  * Utility routines.
 308  */
 309 int     xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno);
 310 int     xfs_da_grow_inode_int(struct xfs_da_args *args, xfs_fileoff_t *bno,
 311                               int count);
 312 int     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);
 315 int     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);
 319 xfs_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);
 322 int     xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
 323                                           struct xfs_buf *dead_buf);
 324
 325 uint xfs_da_hashname(const __uint8_t *name_string, int name_length);
 326 enum xfs_dacmp xfs_da_compname(struct xfs_da_args *args,
 327                                 const unsigned char *name, int len);
 328
 329
 330 xfs_da_state_t *xfs_da_state_alloc(void);
 331 void xfs_da_state_free(xfs_da_state_t *state);
 332
 333 extern struct kmem_zone *xfs_da_state_zone;
 334 extern const struct xfs_nameops xfs_default_nameops;
 335
 336 #endif  /* __XFS_DA_BTREE_H__ */