fs/xfs/xfs_dir2_sf.h

   1 /*
   2  * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #ifndef __XFS_DIR2_SF_H__
  19 #define __XFS_DIR2_SF_H__
  20
  21 /*
  22  * Directory layout when stored internal to an inode.
  23  *
  24  * Small directories are packed as tightly as possible so as to
  25  * fit into the literal area of the inode.
  26  */
  27
  28 struct uio;
  29 struct xfs_dabuf;
  30 struct xfs_da_args;
  31 struct xfs_dir2_block;
  32 struct xfs_inode;
  33 struct xfs_mount;
  34 struct xfs_trans;
  35
  36 /*
  37  * Maximum size of a shortform directory.
  38  */
  39 #define XFS_DIR2_SF_MAX_SIZE    \
  40         (XFS_DINODE_MAX_SIZE - (uint)sizeof(xfs_dinode_core_t) - \
  41          (uint)sizeof(xfs_agino_t))
  42
  43 /*
  44  * Inode number stored as 8 8-bit values.
  45  */
  46 typedef struct { __uint8_t i[8]; } xfs_dir2_ino8_t;
  47
  48 /*
  49  * Inode number stored as 4 8-bit values.
  50  * Works a lot of the time, when all the inode numbers in a directory
  51  * fit in 32 bits.
  52  */
  53 typedef struct { __uint8_t i[4]; } xfs_dir2_ino4_t;
  54
  55 typedef union {
  56         xfs_dir2_ino8_t i8;
  57         xfs_dir2_ino4_t i4;
  58 } xfs_dir2_inou_t;
  59 #define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL)
  60
  61 /*
  62  * Normalized offset (in a data block) of the entry, really xfs_dir2_data_off_t.
  63  * Only need 16 bits, this is the byte offset into the single block form.
  64  */
  65 typedef struct { __uint8_t i[2]; } xfs_dir2_sf_off_t;
  66
  67 /*
  68  * The parent directory has a dedicated field, and the self-pointer must
  69  * be calculated on the fly.
  70  *
  71  * Entries are packed toward the top as tightly as possible.  The header
  72  * and the elements must be memcpy'd out into a work area to get correct
  73  * alignment for the inode number fields.
  74  */
  75 typedef struct xfs_dir2_sf_hdr {
  76         __uint8_t               count;          /* count of entries */
  77         __uint8_t               i8count;        /* count of 8-byte inode #s */
  78         xfs_dir2_inou_t         parent;         /* parent dir inode number */
  79 } xfs_dir2_sf_hdr_t;
  80
  81 typedef struct xfs_dir2_sf_entry {
  82         __uint8_t               namelen;        /* actual name length */
  83         xfs_dir2_sf_off_t       offset;         /* saved offset */
  84         __uint8_t               name[1];        /* name, variable size */
  85         xfs_dir2_inou_t         inumber;        /* inode number, var. offset */
  86 } xfs_dir2_sf_entry_t;
  87
  88 typedef struct xfs_dir2_sf {
  89         xfs_dir2_sf_hdr_t       hdr;            /* shortform header */
  90         xfs_dir2_sf_entry_t     list[1];        /* shortform entries */
  91 } xfs_dir2_sf_t;
  92
  93 static inline int xfs_dir2_sf_hdr_size(int i8count)
  94 {
  95         return ((uint)sizeof(xfs_dir2_sf_hdr_t) - \
  96                 ((i8count) == 0) * \
  97                 ((uint)sizeof(xfs_dir2_ino8_t) - (uint)sizeof(xfs_dir2_ino4_t)));
  98 }
  99
 100 static inline xfs_dir2_inou_t *xfs_dir2_sf_inumberp(xfs_dir2_sf_entry_t *sfep)
 101 {
 102         return (xfs_dir2_inou_t *)&(sfep)->name[(sfep)->namelen];
 103 }
 104
 105 static inline xfs_intino_t
 106 xfs_dir2_sf_get_inumber(xfs_dir2_sf_t *sfp, xfs_dir2_inou_t *from)
 107 {
 108         return ((sfp)->hdr.i8count == 0 ? \
 109                 (xfs_intino_t)XFS_GET_DIR_INO4((from)->i4) : \
 110                 (xfs_intino_t)XFS_GET_DIR_INO8((from)->i8));
 111 }
 112
 113 static inline void xfs_dir2_sf_put_inumber(xfs_dir2_sf_t *sfp, xfs_ino_t *from,
 114                                                 xfs_dir2_inou_t *to)
 115 {
 116         if ((sfp)->hdr.i8count == 0)
 117                 XFS_PUT_DIR_INO4(*(from), (to)->i4);
 118         else
 119                 XFS_PUT_DIR_INO8(*(from), (to)->i8);
 120 }
 121
 122 static inline xfs_dir2_data_aoff_t
 123 xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
 124 {
 125         return INT_GET_UNALIGNED_16_BE(&(sfep)->offset.i);
 126 }
 127
 128 static inline void
 129 xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
 130 {
 131         INT_SET_UNALIGNED_16_BE(&(sfep)->offset.i, off);
 132 }
 133
 134 static inline int xfs_dir2_sf_entsize_byname(xfs_dir2_sf_t *sfp, int len)
 135 {
 136         return ((uint)sizeof(xfs_dir2_sf_entry_t) - 1 + (len) - \
 137                 ((sfp)->hdr.i8count == 0) * \
 138                 ((uint)sizeof(xfs_dir2_ino8_t) - (uint)sizeof(xfs_dir2_ino4_t)));
 139 }
 140
 141 static inline int
 142 xfs_dir2_sf_entsize_byentry(xfs_dir2_sf_t *sfp, xfs_dir2_sf_entry_t *sfep)
 143 {
 144         return ((uint)sizeof(xfs_dir2_sf_entry_t) - 1 + (sfep)->namelen - \
 145                 ((sfp)->hdr.i8count == 0) * \
 146                 ((uint)sizeof(xfs_dir2_ino8_t) - (uint)sizeof(xfs_dir2_ino4_t)));
 147 }
 148
 149 static inline xfs_dir2_sf_entry_t *xfs_dir2_sf_firstentry(xfs_dir2_sf_t *sfp)
 150 {
 151         return ((xfs_dir2_sf_entry_t *) \
 152                 ((char *)(sfp) + xfs_dir2_sf_hdr_size(sfp->hdr.i8count)));
 153 }
 154
 155 static inline xfs_dir2_sf_entry_t *
 156 xfs_dir2_sf_nextentry(xfs_dir2_sf_t *sfp, xfs_dir2_sf_entry_t *sfep)
 157 {
 158         return ((xfs_dir2_sf_entry_t *) \
 159                 ((char *)(sfep) + xfs_dir2_sf_entsize_byentry(sfp,sfep)));
 160 }
 161
 162 /*
 163  * Functions.
 164  */
 165 extern int xfs_dir2_block_sfsize(struct xfs_inode *dp,
 166                                  struct xfs_dir2_block *block,
 167                                  xfs_dir2_sf_hdr_t *sfhp);
 168 extern int xfs_dir2_block_to_sf(struct xfs_da_args *args, struct xfs_dabuf *bp,
 169                                 int size, xfs_dir2_sf_hdr_t *sfhp);
 170 extern int xfs_dir2_sf_addname(struct xfs_da_args *args);
 171 extern int xfs_dir2_sf_create(struct xfs_da_args *args, xfs_ino_t pino);
 172 extern int xfs_dir2_sf_getdents(struct xfs_inode *dp, struct uio *uio,
 173                                 int *eofp, struct xfs_dirent *dbp,
 174                                 xfs_dir2_put_t put);
 175 extern int xfs_dir2_sf_lookup(struct xfs_da_args *args);
 176 extern int xfs_dir2_sf_removename(struct xfs_da_args *args);
 177 extern int xfs_dir2_sf_replace(struct xfs_da_args *args);
 178
 179 #endif  /* __XFS_DIR2_SF_H__ */