fs/xfs/xfs_dir2_data.h

   1 /*
   2  * Copyright (c) 2000 Silicon Graphics, Inc.  All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it would be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  11  *
  12  * Further, this software is distributed without any warranty that it is
  13  * free of the rightful claim of any third person regarding infringement
  14  * or the like.  Any license provided herein, whether implied or
  15  * otherwise, applies only to this software file.  Patent licenses, if
  16  * any, provided herein do not apply to combinations of this program with
  17  * other software, or any other product whatsoever.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write the Free Software Foundation, Inc., 59
  21  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
  22  *
  23  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
  24  * Mountain View, CA  94043, or:
  25  *
  26  * http://www.sgi.com
  27  *
  28  * For further information regarding this notice, see:
  29  *
  30  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
  31  */
  32 #ifndef __XFS_DIR2_DATA_H__
  33 #define __XFS_DIR2_DATA_H__
  34
  35 /*
  36  * Directory format 2, data block structures.
  37  */
  38
  39 struct xfs_dabuf;
  40 struct xfs_da_args;
  41 struct xfs_inode;
  42 struct xfs_trans;
  43
  44 /*
  45  * Constants.
  46  */
  47 #define XFS_DIR2_DATA_MAGIC     0x58443244      /* XD2D: for multiblock dirs */
  48 #define XFS_DIR2_DATA_ALIGN_LOG 3               /* i.e., 8 bytes */
  49 #define XFS_DIR2_DATA_ALIGN     (1 << XFS_DIR2_DATA_ALIGN_LOG)
  50 #define XFS_DIR2_DATA_FREE_TAG  0xffff
  51 #define XFS_DIR2_DATA_FD_COUNT  3
  52
  53 /*
  54  * Directory address space divided into sections,
  55  * spaces separated by 32gb.
  56  */
  57 #define XFS_DIR2_SPACE_SIZE     (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
  58 #define XFS_DIR2_DATA_SPACE     0
  59 #define XFS_DIR2_DATA_OFFSET    (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
  60 #define XFS_DIR2_DATA_FIRSTDB(mp)       \
  61         XFS_DIR2_BYTE_TO_DB(mp, XFS_DIR2_DATA_OFFSET)
  62
  63 /*
  64  * Offsets of . and .. in data space (always block 0)
  65  */
  66 #define XFS_DIR2_DATA_DOT_OFFSET        \
  67         ((xfs_dir2_data_aoff_t)sizeof(xfs_dir2_data_hdr_t))
  68 #define XFS_DIR2_DATA_DOTDOT_OFFSET     \
  69         (XFS_DIR2_DATA_DOT_OFFSET + XFS_DIR2_DATA_ENTSIZE(1))
  70 #define XFS_DIR2_DATA_FIRST_OFFSET              \
  71         (XFS_DIR2_DATA_DOTDOT_OFFSET + XFS_DIR2_DATA_ENTSIZE(2))
  72
  73 /*
  74  * Structures.
  75  */
  76
  77 /*
  78  * Describe a free area in the data block.
  79  * The freespace will be formatted as a xfs_dir2_data_unused_t.
  80  */
  81 typedef struct xfs_dir2_data_free {
  82         xfs_dir2_data_off_t     offset;         /* start of freespace */
  83         xfs_dir2_data_off_t     length;         /* length of freespace */
  84 } xfs_dir2_data_free_t;
  85
  86 /*
  87  * Header for the data blocks.
  88  * Always at the beginning of a directory-sized block.
  89  * The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
  90  */
  91 typedef struct xfs_dir2_data_hdr {
  92         __uint32_t              magic;          /* XFS_DIR2_DATA_MAGIC */
  93                                                 /* or XFS_DIR2_BLOCK_MAGIC */
  94         xfs_dir2_data_free_t    bestfree[XFS_DIR2_DATA_FD_COUNT];
  95 } xfs_dir2_data_hdr_t;
  96
  97 /*
  98  * Active entry in a data block.  Aligned to 8 bytes.
  99  * Tag appears as the last 2 bytes.
 100  */
 101 typedef struct xfs_dir2_data_entry {
 102         xfs_ino_t               inumber;        /* inode number */
 103         __uint8_t               namelen;        /* name length */
 104         __uint8_t               name[1];        /* name bytes, no null */
 105                                                 /* variable offset */
 106         xfs_dir2_data_off_t     tag;            /* starting offset of us */
 107 } xfs_dir2_data_entry_t;
 108
 109 /*
 110  * Unused entry in a data block.  Aligned to 8 bytes.
 111  * Tag appears as the last 2 bytes.
 112  */
 113 typedef struct xfs_dir2_data_unused {
 114         __uint16_t              freetag;        /* XFS_DIR2_DATA_FREE_TAG */
 115         xfs_dir2_data_off_t     length;         /* total free length */
 116                                                 /* variable offset */
 117         xfs_dir2_data_off_t     tag;            /* starting offset of us */
 118 } xfs_dir2_data_unused_t;
 119
 120 typedef union {
 121         xfs_dir2_data_entry_t   entry;
 122         xfs_dir2_data_unused_t  unused;
 123 } xfs_dir2_data_union_t;
 124
 125 /*
 126  * Generic data block structure, for xfs_db.
 127  */
 128 typedef struct xfs_dir2_data {
 129         xfs_dir2_data_hdr_t     hdr;            /* magic XFS_DIR2_DATA_MAGIC */
 130         xfs_dir2_data_union_t   u[1];
 131 } xfs_dir2_data_t;
 132
 133 /*
 134  * Macros.
 135  */
 136
 137 /*
 138  * Size of a data entry.
 139  */
 140 #define XFS_DIR2_DATA_ENTSIZE(n)        xfs_dir2_data_entsize(n)
 141 static inline int xfs_dir2_data_entsize(int n)
 142 {
 143         return (int)roundup(offsetof(xfs_dir2_data_entry_t, name[0]) + (n) + \
 144                  (uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
 145 }
 146
 147 /*
 148  * Pointer to an entry's tag word.
 149  */
 150 #define XFS_DIR2_DATA_ENTRY_TAG_P(dep)  xfs_dir2_data_entry_tag_p(dep)
 151 static inline xfs_dir2_data_off_t *
 152 xfs_dir2_data_entry_tag_p(xfs_dir2_data_entry_t *dep)
 153 {
 154         return (xfs_dir2_data_off_t *) \
 155                  ((char *)(dep) + XFS_DIR2_DATA_ENTSIZE((dep)->namelen) - \
 156                   (uint)sizeof(xfs_dir2_data_off_t));
 157 }
 158
 159 /*
 160  * Pointer to a freespace's tag word.
 161  */
 162 #define XFS_DIR2_DATA_UNUSED_TAG_P(dup) \
 163         xfs_dir2_data_unused_tag_p(dup)
 164 static inline xfs_dir2_data_off_t *
 165 xfs_dir2_data_unused_tag_p(xfs_dir2_data_unused_t *dup)
 166 {
 167         return (xfs_dir2_data_off_t *) \
 168                  ((char *)(dup) + INT_GET((dup)->length, ARCH_CONVERT) \
 169                                 - (uint)sizeof(xfs_dir2_data_off_t));
 170 }
 171
 172 /*
 173  * Function declarations.
 174  */
 175 #ifdef DEBUG
 176 extern void xfs_dir2_data_check(struct xfs_inode *dp, struct xfs_dabuf *bp);
 177 #else
 178 #define xfs_dir2_data_check(dp,bp)
 179 #endif
 180 extern xfs_dir2_data_free_t *xfs_dir2_data_freefind(xfs_dir2_data_t *d,
 181                                 xfs_dir2_data_unused_t *dup);
 182 extern xfs_dir2_data_free_t *xfs_dir2_data_freeinsert(xfs_dir2_data_t *d,
 183                                 xfs_dir2_data_unused_t *dup, int *loghead);
 184 extern void xfs_dir2_data_freescan(struct xfs_mount *mp, xfs_dir2_data_t *d,
 185                                 int *loghead, char *aendp);
 186 extern int xfs_dir2_data_init(struct xfs_da_args *args, xfs_dir2_db_t blkno,
 187                                 struct xfs_dabuf **bpp);
 188 extern void xfs_dir2_data_log_entry(struct xfs_trans *tp, struct xfs_dabuf *bp,
 189                                 xfs_dir2_data_entry_t *dep);
 190 extern void xfs_dir2_data_log_header(struct xfs_trans *tp,
 191                                 struct xfs_dabuf *bp);
 192 extern void xfs_dir2_data_log_unused(struct xfs_trans *tp, struct xfs_dabuf *bp,
 193                                 xfs_dir2_data_unused_t *dup);
 194 extern void xfs_dir2_data_make_free(struct xfs_trans *tp, struct xfs_dabuf *bp,
 195                                 xfs_dir2_data_aoff_t offset,
 196                                 xfs_dir2_data_aoff_t len, int *needlogp,
 197                                 int *needscanp);
 198 extern void xfs_dir2_data_use_free(struct xfs_trans *tp, struct xfs_dabuf *bp,
 199                                xfs_dir2_data_unused_t *dup,
 200                                xfs_dir2_data_aoff_t offset,
 201                                xfs_dir2_data_aoff_t len, int *needlogp,
 202                                int *needscanp);
 203
 204 #endif  /* __XFS_DIR2_DATA_H__ */