linux/fs/exofs/common.h
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   1/*
   2 * common.h - Common definitions for both Kernel and user-mode utilities
   3 *
   4 * Copyright (C) 2005, 2006
   5 * Avishay Traeger (avishay@gmail.com)
   6 * Copyright (C) 2008, 2009
   7 * Boaz Harrosh <bharrosh@panasas.com>
   8 *
   9 * Copyrights for code taken from ext2:
  10 *     Copyright (C) 1992, 1993, 1994, 1995
  11 *     Remy Card (card@masi.ibp.fr)
  12 *     Laboratoire MASI - Institut Blaise Pascal
  13 *     Universite Pierre et Marie Curie (Paris VI)
  14 *     from
  15 *     linux/fs/minix/inode.c
  16 *     Copyright (C) 1991, 1992  Linus Torvalds
  17 *
  18 * This file is part of exofs.
  19 *
  20 * exofs is free software; you can redistribute it and/or modify
  21 * it under the terms of the GNU General Public License as published by
  22 * the Free Software Foundation.  Since it is based on ext2, and the only
  23 * valid version of GPL for the Linux kernel is version 2, the only valid
  24 * version of GPL for exofs is version 2.
  25 *
  26 * exofs is distributed in the hope that it will be useful,
  27 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  28 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29 * GNU General Public License for more details.
  30 *
  31 * You should have received a copy of the GNU General Public License
  32 * along with exofs; if not, write to the Free Software
  33 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  34 */
  35
  36#ifndef __EXOFS_COM_H__
  37#define __EXOFS_COM_H__
  38
  39#include <linux/types.h>
  40
  41#include <scsi/osd_attributes.h>
  42#include <scsi/osd_initiator.h>
  43#include <scsi/osd_sec.h>
  44
  45/****************************************************************************
  46 * Object ID related defines
  47 * NOTE: inode# = object ID - EXOFS_OBJ_OFF
  48 ****************************************************************************/
  49#define EXOFS_MIN_PID   0x10000 /* Smallest partition ID */
  50#define EXOFS_OBJ_OFF   0x10000 /* offset for objects */
  51#define EXOFS_SUPER_ID  0x10000 /* object ID for on-disk superblock */
  52#define EXOFS_DEVTABLE_ID 0x10001 /* object ID for on-disk device table */
  53#define EXOFS_ROOT_ID   0x10002 /* object ID for root directory */
  54
  55/* exofs Application specific page/attribute */
  56/* Inode attrs */
  57# define EXOFS_APAGE_FS_DATA    (OSD_APAGE_APP_DEFINED_FIRST + 3)
  58# define EXOFS_ATTR_INODE_DATA  1
  59# define EXOFS_ATTR_INODE_FILE_LAYOUT   2
  60# define EXOFS_ATTR_INODE_DIR_LAYOUT    3
  61/* Partition attrs */
  62# define EXOFS_APAGE_SB_DATA    (0xF0000000U + 3)
  63# define EXOFS_ATTR_SB_STATS    1
  64
  65/*
  66 * The maximum number of files we can have is limited by the size of the
  67 * inode number.  This is the largest object ID that the file system supports.
  68 * Object IDs 0, 1, and 2 are always in use (see above defines).
  69 */
  70enum {
  71        EXOFS_MAX_INO_ID = (sizeof(ino_t) * 8 == 64) ? ULLONG_MAX :
  72                                        (1ULL << (sizeof(ino_t) * 8ULL - 1ULL)),
  73        EXOFS_MAX_ID     = (EXOFS_MAX_INO_ID - 1 - EXOFS_OBJ_OFF),
  74};
  75
  76/****************************************************************************
  77 * Misc.
  78 ****************************************************************************/
  79#define EXOFS_BLKSHIFT  12
  80#define EXOFS_BLKSIZE   (1UL << EXOFS_BLKSHIFT)
  81
  82/****************************************************************************
  83 * superblock-related things
  84 ****************************************************************************/
  85#define EXOFS_SUPER_MAGIC       0x5DF5
  86
  87/*
  88 * The file system control block - stored in object EXOFS_SUPER_ID's data.
  89 * This is where the in-memory superblock is stored on disk.
  90 */
  91enum {EXOFS_FSCB_VER = 1, EXOFS_DT_VER = 1};
  92struct exofs_fscb {
  93        __le64  s_nextid;       /* Only used after mkfs */
  94        __le64  s_numfiles;     /* Only used after mkfs */
  95        __le32  s_version;      /* == EXOFS_FSCB_VER */
  96        __le16  s_magic;        /* Magic signature */
  97        __le16  s_newfs;        /* Non-zero if this is a new fs */
  98
  99        /* From here on it's a static part, only written by mkexofs */
 100        __le64  s_dev_table_oid;   /* Resurved, not used */
 101        __le64  s_dev_table_count; /* == 0 means no dev_table */
 102} __packed;
 103
 104/*
 105 * This struct is set on the FS partition's attributes.
 106 * [EXOFS_APAGE_SB_DATA, EXOFS_ATTR_SB_STATS] and is written together
 107 * with the create command, to atomically persist the sb writeable information.
 108 */
 109struct exofs_sb_stats {
 110        __le64  s_nextid;       /* Highest object ID used */
 111        __le64  s_numfiles;     /* Number of files on fs */
 112} __packed;
 113
 114/*
 115 * Describes the raid used in the FS. It is part of the device table.
 116 * This here is taken from the pNFS-objects definition. In exofs we
 117 * use one raid policy through-out the filesystem. (NOTE: the funny
 118 * alignment at beginning. We take care of it at exofs_device_table.
 119 */
 120struct exofs_dt_data_map {
 121        __le32  cb_num_comps;
 122        __le64  cb_stripe_unit;
 123        __le32  cb_group_width;
 124        __le32  cb_group_depth;
 125        __le32  cb_mirror_cnt;
 126        __le32  cb_raid_algorithm;
 127} __packed;
 128
 129/*
 130 * This is an osd device information descriptor. It is a single entry in
 131 * the exofs device table. It describes an osd target lun which
 132 * contains data belonging to this FS. (Same partition_id on all devices)
 133 */
 134struct exofs_dt_device_info {
 135        __le32  systemid_len;
 136        u8      systemid[OSD_SYSTEMID_LEN];
 137        __le64  long_name_offset;       /* If !0 then offset-in-file */
 138        __le32  osdname_len;            /* */
 139        u8      osdname[44];            /* Embbeded, Usually an asci uuid */
 140} __packed;
 141
 142/*
 143 * The EXOFS device table - stored in object EXOFS_DEVTABLE_ID's data.
 144 * It contains the raid used for this multy-device FS and an array of
 145 * participating devices.
 146 */
 147struct exofs_device_table {
 148        __le32                          dt_version;     /* == EXOFS_DT_VER */
 149        struct exofs_dt_data_map        dt_data_map;    /* Raid policy to use */
 150
 151        /* Resurved space For future use. Total includeing this:
 152         * (8 * sizeof(le64))
 153         */
 154        __le64                          __Resurved[4];
 155
 156        __le64                          dt_num_devices; /* Array size */
 157        struct exofs_dt_device_info     dt_dev_table[]; /* Array of devices */
 158} __packed;
 159
 160/****************************************************************************
 161 * inode-related things
 162 ****************************************************************************/
 163#define EXOFS_IDATA             5
 164
 165/*
 166 * The file control block - stored in an object's attributes.  This is where
 167 * the in-memory inode is stored on disk.
 168 */
 169struct exofs_fcb {
 170        __le64  i_size;                 /* Size of the file */
 171        __le16  i_mode;                 /* File mode */
 172        __le16  i_links_count;          /* Links count */
 173        __le32  i_uid;                  /* Owner Uid */
 174        __le32  i_gid;                  /* Group Id */
 175        __le32  i_atime;                /* Access time */
 176        __le32  i_ctime;                /* Creation time */
 177        __le32  i_mtime;                /* Modification time */
 178        __le32  i_flags;                /* File flags (unused for now)*/
 179        __le32  i_generation;           /* File version (for NFS) */
 180        __le32  i_data[EXOFS_IDATA];    /* Short symlink names and device #s */
 181};
 182
 183#define EXOFS_INO_ATTR_SIZE     sizeof(struct exofs_fcb)
 184
 185/* This is the Attribute the fcb is stored in */
 186static const struct __weak osd_attr g_attr_inode_data = ATTR_DEF(
 187        EXOFS_APAGE_FS_DATA,
 188        EXOFS_ATTR_INODE_DATA,
 189        EXOFS_INO_ATTR_SIZE);
 190
 191/****************************************************************************
 192 * dentry-related things
 193 ****************************************************************************/
 194#define EXOFS_NAME_LEN  255
 195
 196/*
 197 * The on-disk directory entry
 198 */
 199struct exofs_dir_entry {
 200        __le64          inode_no;               /* inode number           */
 201        __le16          rec_len;                /* directory entry length */
 202        u8              name_len;               /* name length            */
 203        u8              file_type;              /* umm...file type        */
 204        char            name[EXOFS_NAME_LEN];   /* file name              */
 205};
 206
 207enum {
 208        EXOFS_FT_UNKNOWN,
 209        EXOFS_FT_REG_FILE,
 210        EXOFS_FT_DIR,
 211        EXOFS_FT_CHRDEV,
 212        EXOFS_FT_BLKDEV,
 213        EXOFS_FT_FIFO,
 214        EXOFS_FT_SOCK,
 215        EXOFS_FT_SYMLINK,
 216        EXOFS_FT_MAX
 217};
 218
 219#define EXOFS_DIR_PAD                   4
 220#define EXOFS_DIR_ROUND                 (EXOFS_DIR_PAD - 1)
 221#define EXOFS_DIR_REC_LEN(name_len) \
 222        (((name_len) + offsetof(struct exofs_dir_entry, name)  + \
 223          EXOFS_DIR_ROUND) & ~EXOFS_DIR_ROUND)
 224
 225/*
 226 * The on-disk (optional) layout structure.
 227 * sits in an EXOFS_ATTR_INODE_FILE_LAYOUT or EXOFS_ATTR_INODE_DIR_LAYOUT
 228 * attribute, attached to any inode, usually to a directory.
 229 */
 230
 231enum exofs_inode_layout_gen_functions {
 232        LAYOUT_MOVING_WINDOW = 0,
 233        LAYOUT_IMPLICT = 1,
 234};
 235
 236struct exofs_on_disk_inode_layout {
 237        __le16 gen_func; /* One of enum exofs_inode_layout_gen_functions */
 238        __le16 pad;
 239        union {
 240                /* gen_func == LAYOUT_MOVING_WINDOW (default) */
 241                struct exofs_layout_sliding_window {
 242                        __le32 num_devices; /* first n devices in global-table*/
 243                } sliding_window __packed;
 244
 245                /* gen_func == LAYOUT_IMPLICT */
 246                struct exofs_layout_implict_list {
 247                        struct exofs_dt_data_map data_map;
 248                        /* Variable array of size data_map.cb_num_comps. These
 249                         * are device indexes of the devices in the global table
 250                         */
 251                        __le32 dev_indexes[];
 252                } implict __packed;
 253        };
 254} __packed;
 255
 256static inline size_t exofs_on_disk_inode_layout_size(unsigned max_devs)
 257{
 258        return sizeof(struct exofs_on_disk_inode_layout) +
 259                max_devs * sizeof(__le32);
 260}
 261
 262#endif /*ifndef __EXOFS_COM_H__*/
 263
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