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 fit into the
  25  * literal area of the inode.  They consist of a single xfs_dir2_sf_hdr header
  26  * followed by zero or more xfs_dir2_sf_entry structures.  Due the different
  27  * inode number storage size and the variable length name field in
  28  * the xfs_dir2_sf_entry all these structure are variable length, and the
  29  * accessors in this file should be used to iterate over them.
  30  */
  31
  32 struct uio;
  33 struct xfs_dabuf;
  34 struct xfs_da_args;
  35 struct xfs_dir2_data_hdr;
  36 struct xfs_inode;
  37 struct xfs_mount;
  38 struct xfs_trans;
  39
  40 /*
  41  * Inode number stored as 8 8-bit values.
  42  */
  43 typedef struct { __uint8_t i[8]; } xfs_dir2_ino8_t;
  44
  45 /*
  46  * Inode number stored as 4 8-bit values.
  47  * Works a lot of the time, when all the inode numbers in a directory
  48  * fit in 32 bits.
  49  */
  50 typedef struct { __uint8_t i[4]; } xfs_dir2_ino4_t;
  51
  52 typedef union {
  53         xfs_dir2_ino8_t i8;
  54         xfs_dir2_ino4_t i4;
  55 } xfs_dir2_inou_t;
  56 #define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL)
  57
  58 /*
  59  * Normalized offset (in a data block) of the entry, really xfs_dir2_data_off_t.
  60  * Only need 16 bits, this is the byte offset into the single block form.
  61  */
  62 typedef struct { __uint8_t i[2]; } __arch_pack xfs_dir2_sf_off_t;
  63
  64 /*
  65  * The parent directory has a dedicated field, and the self-pointer must
  66  * be calculated on the fly.
  67  *
  68  * Entries are packed toward the top as tightly as possible, and thus may
  69  * be misaligned.  Care needs to be taken to access them through special
  70  * helpers or copy them into aligned variables first.
  71  */
  72 typedef struct xfs_dir2_sf_hdr {
  73         __uint8_t               count;          /* count of entries */
  74         __uint8_t               i8count;        /* count of 8-byte inode #s */
  75         xfs_dir2_inou_t         parent;         /* parent dir inode number */
  76 } __arch_pack xfs_dir2_sf_hdr_t;
  77
  78 typedef struct xfs_dir2_sf_entry {
  79         __u8                    namelen;        /* actual name length */
  80         xfs_dir2_sf_off_t       offset;         /* saved offset */
  81         __u8                    name[];         /* name, variable size */
  82         /*
  83          * A xfs_dir2_ino8_t or xfs_dir2_ino4_t follows here, at a
  84          * variable offset after the name.
  85          */
  86 } __arch_pack xfs_dir2_sf_entry_t;
  87
  88 static inline int xfs_dir2_sf_hdr_size(int i8count)
  89 {
  90         return ((uint)sizeof(xfs_dir2_sf_hdr_t) - \
  91                 ((i8count) == 0) * \
  92                 ((uint)sizeof(xfs_dir2_ino8_t) - (uint)sizeof(xfs_dir2_ino4_t)));
  93 }
  94
  95 static inline xfs_dir2_data_aoff_t
  96 xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
  97 {
  98         return get_unaligned_be16(&sfep->offset.i);
  99 }
 100
 101 static inline void
 102 xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
 103 {
 104         put_unaligned_be16(off, &sfep->offset.i);
 105 }
 106
 107 static inline int
 108 xfs_dir2_sf_entsize(struct xfs_dir2_sf_hdr *hdr, int len)
 109 {
 110         return sizeof(struct xfs_dir2_sf_entry) +       /* namelen + offset */
 111                 len +                                   /* name */
 112                 (hdr->i8count ?                         /* ino */
 113                  sizeof(xfs_dir2_ino8_t) :
 114                  sizeof(xfs_dir2_ino4_t));
 115 }
 116
 117 static inline struct xfs_dir2_sf_entry *
 118 xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
 119 {
 120         return (struct xfs_dir2_sf_entry *)
 121                 ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
 122 }
 123
 124 static inline struct xfs_dir2_sf_entry *
 125 xfs_dir2_sf_nextentry(struct xfs_dir2_sf_hdr *hdr,
 126                 struct xfs_dir2_sf_entry *sfep)
 127 {
 128         return (struct xfs_dir2_sf_entry *)
 129                 ((char *)sfep + xfs_dir2_sf_entsize(hdr, sfep->namelen));
 130 }
 131
 132 /*
 133  * Functions.
 134  */
 135 extern xfs_ino_t xfs_dir2_sf_get_parent_ino(struct xfs_dir2_sf_hdr *sfp);
 136 extern xfs_ino_t xfs_dir2_sfe_get_ino(struct xfs_dir2_sf_hdr *sfp,
 137                                       struct xfs_dir2_sf_entry *sfep);
 138 extern int xfs_dir2_block_sfsize(struct xfs_inode *dp,
 139                                  struct xfs_dir2_data_hdr *block,
 140                                  xfs_dir2_sf_hdr_t *sfhp);
 141 extern int xfs_dir2_block_to_sf(struct xfs_da_args *args, struct xfs_dabuf *bp,
 142                                 int size, xfs_dir2_sf_hdr_t *sfhp);
 143 extern int xfs_dir2_sf_addname(struct xfs_da_args *args);
 144 extern int xfs_dir2_sf_create(struct xfs_da_args *args, xfs_ino_t pino);
 145 extern int xfs_dir2_sf_getdents(struct xfs_inode *dp, void *dirent,
 146                                 xfs_off_t *offset, filldir_t filldir);
 147 extern int xfs_dir2_sf_lookup(struct xfs_da_args *args);
 148 extern int xfs_dir2_sf_removename(struct xfs_da_args *args);
 149 extern int xfs_dir2_sf_replace(struct xfs_da_args *args);
 150
 151 #endif  /* __XFS_DIR2_SF_H__ */