common.h

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/*
 * common.h - Common definitions for both Kernel and user-mode utilities
 *
 * Copyright (C) 2005, 2006
 * Avishay Traeger ([email protected])
 * Copyright (C) 2008, 2009
 * Boaz Harrosh <[email protected]>
 *
 * Copyrights for code taken from ext2:
 *     Copyright (C) 1992, 1993, 1994, 1995
 *     Remy Card ([email protected])
 *     Laboratoire MASI - Institut Blaise Pascal
 *     Universite Pierre et Marie Curie (Paris VI)
 *     from
 *     linux/fs/minix/inode.c
 *     Copyright (C) 1991, 1992  Linus Torvalds
 *
 * This file is part of exofs.
 *
 * exofs is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.  Since it is based on ext2, and the only
 * valid version of GPL for the Linux kernel is version 2, the only valid
 * version of GPL for exofs is version 2.
 *
 * exofs is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with exofs; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef __EXOFS_COM_H__
#define __EXOFS_COM_H__

#include <linux/types.h>

#include <scsi/osd_attributes.h>
#include <scsi/osd_initiator.h>
#include <scsi/osd_sec.h>

/****************************************************************************
 * Object ID related defines
 * NOTE: inode# = object ID - EXOFS_OBJ_OFF
 ****************************************************************************/
#define EXOFS_MIN_PID   0x10000 /* Smallest partition ID */
#define EXOFS_OBJ_OFF   0x10000 /* offset for objects */
#define EXOFS_SUPER_ID  0x10000 /* object ID for on-disk superblock */
#define EXOFS_DEVTABLE_ID 0x10001 /* object ID for on-disk device table */
#define EXOFS_ROOT_ID   0x10002 /* object ID for root directory */

/* exofs Application specific page/attribute */
/* Inode attrs */
# define EXOFS_APAGE_FS_DATA    (OSD_APAGE_APP_DEFINED_FIRST + 3)
# define EXOFS_ATTR_INODE_DATA  1
# define EXOFS_ATTR_INODE_FILE_LAYOUT   2
# define EXOFS_ATTR_INODE_DIR_LAYOUT    3
/* Partition attrs */
# define EXOFS_APAGE_SB_DATA    (0xF0000000U + 3)
# define EXOFS_ATTR_SB_STATS    1

/*
 * The maximum number of files we can have is limited by the size of the
 * inode number.  This is the largest object ID that the file system supports.
 * Object IDs 0, 1, and 2 are always in use (see above defines).
 */
enum {
    EXOFS_MAX_INO_ID = (sizeof(ino_t) * 8 == 64) ? ULLONG_MAX :
                    (1ULL << (sizeof(ino_t) * 8ULL - 1ULL)),
    EXOFS_MAX_ID     = (EXOFS_MAX_INO_ID - 1 - EXOFS_OBJ_OFF),
};

/****************************************************************************
 * Misc.
 ****************************************************************************/
#define EXOFS_BLKSHIFT  12
#define EXOFS_BLKSIZE   (1UL << EXOFS_BLKSHIFT)

/****************************************************************************
 * superblock-related things
 ****************************************************************************/
#define EXOFS_SUPER_MAGIC   0x5DF5

/*
 * The file system control block - stored in object EXOFS_SUPER_ID's data.
 * This is where the in-memory superblock is stored on disk.
 */
enum {EXOFS_FSCB_VER = 1, EXOFS_DT_VER = 1};
struct exofs_fscb {
    __le64  s_nextid;   /* Only used after mkfs */
    __le64  s_numfiles; /* Only used after mkfs */
    __le32  s_version;  /* == EXOFS_FSCB_VER */
    __le16  s_magic;    /* Magic signature */
    __le16  s_newfs;    /* Non-zero if this is a new fs */

    /* From here on it's a static part, only written by mkexofs */
    __le64  s_dev_table_oid;   /* Resurved, not used */
    __le64  s_dev_table_count; /* == 0 means no dev_table */
} __packed;

/*
 * This struct is set on the FS partition's attributes.
 * [EXOFS_APAGE_SB_DATA, EXOFS_ATTR_SB_STATS] and is written together
 * with the create command, to atomically persist the sb writeable information.
 */
struct exofs_sb_stats {
    __le64  s_nextid;   /* Highest object ID used */
    __le64  s_numfiles; /* Number of files on fs */
} __packed;

/*
 * Describes the raid used in the FS. It is part of the device table.
 * This here is taken from the pNFS-objects definition. In exofs we
 * use one raid policy through-out the filesystem. (NOTE: the funny
 * alignment at beginning. We take care of it at exofs_device_table.
 */
struct exofs_dt_data_map {
    __le32  cb_num_comps;
    __le64  cb_stripe_unit;
    __le32  cb_group_width;
    __le32  cb_group_depth;
    __le32  cb_mirror_cnt;
    __le32  cb_raid_algorithm;
} __packed;

/*
 * This is an osd device information descriptor. It is a single entry in
 * the exofs device table. It describes an osd target lun which
 * contains data belonging to this FS. (Same partition_id on all devices)
 */
struct exofs_dt_device_info {
    __le32  systemid_len;
    u8  systemid[OSD_SYSTEMID_LEN];
    __le64  long_name_offset;   /* If !0 then offset-in-file */
    __le32  osdname_len;        /* */
    u8  osdname[44];        /* Embbeded, Usually an asci uuid */
} __packed;

/*
 * The EXOFS device table - stored in object EXOFS_DEVTABLE_ID's data.
 * It contains the raid used for this multy-device FS and an array of
 * participating devices.
 */
struct exofs_device_table {
    __le32              dt_version; /* == EXOFS_DT_VER */
    struct exofs_dt_data_map    dt_data_map;    /* Raid policy to use */

    /* Resurved space For future use. Total includeing this:
     * (8 * sizeof(le64))
     */
    __le64              __Resurved[4];

    __le64              dt_num_devices; /* Array size */
    struct exofs_dt_device_info dt_dev_table[]; /* Array of devices */
} __packed;

/****************************************************************************
 * inode-related things
 ****************************************************************************/
#define EXOFS_IDATA     5

/*
 * The file control block - stored in an object's attributes.  This is where
 * the in-memory inode is stored on disk.
 */
struct exofs_fcb {
    __le64  i_size;         /* Size of the file */
    __le16  i_mode;             /* File mode */
    __le16  i_links_count;      /* Links count */
    __le32  i_uid;              /* Owner Uid */
    __le32  i_gid;              /* Group Id */
    __le32  i_atime;            /* Access time */
    __le32  i_ctime;            /* Creation time */
    __le32  i_mtime;            /* Modification time */
    __le32  i_flags;            /* File flags (unused for now)*/
    __le32  i_generation;       /* File version (for NFS) */
    __le32  i_data[EXOFS_IDATA];    /* Short symlink names and device #s */
};

#define EXOFS_INO_ATTR_SIZE sizeof(struct exofs_fcb)

/* This is the Attribute the fcb is stored in */
static const struct __weak osd_attr g_attr_inode_data = ATTR_DEF(
    EXOFS_APAGE_FS_DATA,
    EXOFS_ATTR_INODE_DATA,
    EXOFS_INO_ATTR_SIZE);

/****************************************************************************
 * dentry-related things
 ****************************************************************************/
#define EXOFS_NAME_LEN  255

/*
 * The on-disk directory entry
 */
struct exofs_dir_entry {
    __le64      inode_no;       /* inode number           */
    __le16      rec_len;        /* directory entry length */
    u8      name_len;       /* name length            */
    u8      file_type;      /* umm...file type        */
    char        name[EXOFS_NAME_LEN];   /* file name              */
};

enum {
    EXOFS_FT_UNKNOWN,
    EXOFS_FT_REG_FILE,
    EXOFS_FT_DIR,
    EXOFS_FT_CHRDEV,
    EXOFS_FT_BLKDEV,
    EXOFS_FT_FIFO,
    EXOFS_FT_SOCK,
    EXOFS_FT_SYMLINK,
    EXOFS_FT_MAX
};

#define EXOFS_DIR_PAD           4
#define EXOFS_DIR_ROUND         (EXOFS_DIR_PAD - 1)
#define EXOFS_DIR_REC_LEN(name_len) \
    (((name_len) + offsetof(struct exofs_dir_entry, name)  + \
      EXOFS_DIR_ROUND) & ~EXOFS_DIR_ROUND)

/*
 * The on-disk (optional) layout structure.
 * sits in an EXOFS_ATTR_INODE_FILE_LAYOUT or EXOFS_ATTR_INODE_DIR_LAYOUT
 * attribute, attached to any inode, usually to a directory.
 */

enum exofs_inode_layout_gen_functions {
    LAYOUT_MOVING_WINDOW = 0,
    LAYOUT_IMPLICT = 1,
};

struct exofs_on_disk_inode_layout {
    __le16 gen_func; /* One of enum exofs_inode_layout_gen_functions */
    __le16 pad;
    union {
        /* gen_func == LAYOUT_MOVING_WINDOW (default) */
        struct exofs_layout_sliding_window {
            __le32 num_devices; /* first n devices in global-table*/
        } sliding_window __packed;

        /* gen_func == LAYOUT_IMPLICT */
        struct exofs_layout_implict_list {
            struct exofs_dt_data_map data_map;
            /* Variable array of size data_map.cb_num_comps. These
             * are device indexes of the devices in the global table
             */
            __le32 dev_indexes[];
        } implict __packed;
    };
} __packed;

static inline size_t exofs_on_disk_inode_layout_size(unsigned max_devs)
{
    return sizeof(struct exofs_on_disk_inode_layout) +
        max_devs * sizeof(__le32);
}

#endif /*ifndef __EXOFS_COM_H__*/