android4.0 userdata分区使用ubifs

0.kernel添加ubifs的支持
Device Drivers --->
    Memory Technology Device(MTD) support --->
      UBI - Unsorted block images --->
        <*> Enable UBI - Unsorted block images

File systems --->
    Miscellaneous filesystems --->
        <*> UBIFS file system support
     [*] Advanced compression options
        [*] LZO compression support
        [*] ZLIB compression support
1. andriod/system/core/rootdir/init.rc
    mount yaffs2 mtd@userdata /data nosuid nodev
改为：
    mount ubifs ubi@userdata /data nosuid nodev
2. andriod/system/core/init/builtins.c

在 } else if (!strncmp(source, "loop@", 5)) {
之前加上
+ }else if (!strncmp(source, "ubi@", 4)) {
+ n = ubi_attach_mtd(source + 4);
+ if (n < 0) {
+ return -1;
+ }
+ sprintf(tmp, "/dev/ubi%d_0", n);
+ if (wait)
+ wait_for_file(tmp, COMMAND_RETRY_TIMEOUT);
+ if (mount(tmp, target, system, flags, options) < 0) {
+ ubi_detach_dev(n);
+ return -1;
+ }
+ return 0;
+ }else if (!strncmp(source, "loop@", 5)) {

3. andriod/system/core/init/init.c

在static int property_triggers_enabled = 0;之后加上
+static unsigned ubifs_enabled = 1;
static int set_init_properties_action(int nargs, char **args)
{
    property_set("ro.revision", tmp);
+ property_set("ro.ubifs",ubifs_enabled ? "1" : "0");
    return 0;
}

int main(int argc, char **argv)
{
   action_for_each_trigger("post-fs", action_add_queue_tail);
+ action_for_each_trigger("ubi-fs", action_add_queue_tail);
}

4. andriod/system/core/init/util.h
void get_hardware_name(char *hardware, unsigned int *revision);
+int ubi_attach_mtd(const char *name);
+int ubi_detach_dev(int dev);

5. andriod/system/core/init/util.c
#include <sys/un.h>
+#include <sys/ioctl.h>

#include "util.h"
+#include "ubi-user.h"

+#define UBI_CTRL_DEV "/dev/ubi_ctrl"
+#define UBI_SYS_PATH "/sys/class/ubi"

在最后添加下面三个函数
static int ubi_dev_read_int(int dev, const char *file, int def)
{
    int fd, val = def;
    char path[128], buf[64];
    sprintf(path, UBI_SYS_PATH "/ubi%d/%s", dev, file);
    wait_for_file(path, 5);
    fd = open(path, O_RDONLY);
    if (fd == -1) {
        return val;
    }
    if (read(fd, buf, 64) > 0) {
        val = atoi(buf);
    }
    close(fd);
    return val;
}
int ubi_attach_mtd(const char *name)
{
    int ret;
    int mtd_num, ubi_num;
    int ubi_ctrl, ubi_dev;
    int vols, avail_lebs, leb_size;
    char path[128];
    struct ubi_attach_req attach_req;
    struct ubi_mkvol_req mkvol_req;

    mtd_num = mtd_name_to_number(name);
    if (mtd_num == -1) {
        return -1;
    }
    ubi_ctrl = open(UBI_CTRL_DEV, O_RDONLY);
    if (ubi_ctrl == -1) {
        return -1;
    }
    memset(&attach_req, 0, sizeof(struct ubi_attach_req));
    attach_req.ubi_num = UBI_DEV_NUM_AUTO;
    attach_req.mtd_num = mtd_num;
    ret = ioctl(ubi_ctrl, UBI_IOCATT, &attach_req);
    if (ret == -1) {
        close(ubi_ctrl);
        return -1;
    }
    ubi_num = attach_req.ubi_num;

    vols = ubi_dev_read_int(ubi_num, "volumes_count", -1);
    if (vols == 0) {
        sprintf(path, "/dev/ubi%d", ubi_num);
        ubi_dev = open(path, O_RDONLY);
        if (ubi_dev == -1) {
            close(ubi_ctrl);
            return ubi_num;
        }

        avail_lebs = ubi_dev_read_int(ubi_num, "avail_eraseblocks", 0);
        leb_size = ubi_dev_read_int(ubi_num, "eraseblock_size", 0);
        memset(&mkvol_req, 0, sizeof(struct ubi_mkvol_req));
        mkvol_req.vol_id = UBI_VOL_NUM_AUTO;
        mkvol_req.alignment = 1;
        mkvol_req.bytes = (long long)avail_lebs * leb_size;
        mkvol_req.vol_type = UBI_DYNAMIC_VOLUME;
        ret = snprintf(mkvol_req.name, UBI_MAX_VOLUME_NAME + 1, "%s", name);
        mkvol_req.name_len = ret;
        ioctl(ubi_dev, UBI_IOCMKVOL, &mkvol_req);
        close(ubi_dev);
    }
    close(ubi_ctrl);
    return ubi_num;
}

int ubi_detach_dev(int dev)
{
    int ret, ubi_ctrl;
    ubi_ctrl = open(UBI_CTRL_DEV, O_RDONLY);
    if (ubi_ctrl == -1) {
        return -1;
    }
    ret = ioctl(ubi_ctrl, UBI_IOCDET, &dev);
    close(ubi_ctrl);
    return ret;
}

6.增加文件
andriod/system/core/init/ubi-user.h
/*
 * Copyright (c) International Business Machines Corp., 2006
 *
 * This program 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Artem Bityutskiy (Битюцкий Артём)
 */

#ifndef __UBI_USER_H__
#define __UBI_USER_H__

/*
 * UBI device creation (the same as MTD device attachment)
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
 * control device. The caller has to properly fill and pass
 * &struct ubi_attach_req object - UBI will attach the MTD device specified in
 * the request and return the newly created UBI device number as the ioctl
 * return value.
 *
 * UBI device deletion (the same as MTD device detachment)
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
 * control device.
 *
 * UBI volume creation
 * ~~~~~~~~~~~~~~~~~~~
 *
 * UBI volumes are created via the %UBI_IOCMKVOL IOCTL command of UBI character
 * device. A &struct ubi_mkvol_req object has to be properly filled and a
 * pointer to it has to be passed to the IOCTL.
 *
 * UBI volume deletion
 * ~~~~~~~~~~~~~~~~~~~
 *
 * To delete a volume, the %UBI_IOCRMVOL IOCTL command of the UBI character
 * device should be used. A pointer to the 32-bit volume ID hast to be passed
 * to the IOCTL.
 *
 * UBI volume re-size
 * ~~~~~~~~~~~~~~~~~~
 *
 * To re-size a volume, the %UBI_IOCRSVOL IOCTL command of the UBI character
 * device should be used. A &struct ubi_rsvol_req object has to be properly
 * filled and a pointer to it has to be passed to the IOCTL.
 *
 * UBI volume update
 * ~~~~~~~~~~~~~~~~~
 *
 * Volume update should be done via the %UBI_IOCVOLUP IOCTL command of the
 * corresponding UBI volume character device. A pointer to a 64-bit update
 * size should be passed to the IOCTL. After this, UBI expects user to write
 * this number of bytes to the volume character device. The update is finished
 * when the claimed number of bytes is passed. So, the volume update sequence
 * is something like:
 *
 * fd = open("/dev/my_volume");
 * ioctl(fd, UBI_IOCVOLUP, &image_size);
 * write(fd, buf, image_size);
 * close(fd);
 *
 * Atomic eraseblock change
 * ~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * Atomic eraseblock change operation is done via the %UBI_IOCEBCH IOCTL
 * command of the corresponding UBI volume character device. A pointer to
 * &struct ubi_leb_change_req has to be passed to the IOCTL. Then the user is
 * expected to write the requested amount of bytes. This is similar to the
 * "volume update" IOCTL.
 */

/*
 * When a new UBI volume or UBI device is created, users may either specify the
 * volume/device number they want to create or to let UBI automatically assign
 * the number using these constants.
 */
#define UBI_VOL_NUM_AUTO (-1)
#define UBI_DEV_NUM_AUTO (-1)

/* Maximum volume name length */
#define UBI_MAX_VOLUME_NAME 127

/* IOCTL commands of UBI character devices */

#define UBI_IOC_MAGIC 'o'

/* Create an UBI volume */
#define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
/* Remove an UBI volume */
#define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, int32_t)
/* Re-size an UBI volume */
#define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)

/* IOCTL commands of the UBI control character device */

#define UBI_CTRL_IOC_MAGIC 'o'

/* Attach an MTD device */
#define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
/* Detach an MTD device */
#define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, int32_t)

/* IOCTL commands of UBI volume character devices */

#define UBI_VOL_IOC_MAGIC 'O'

/* Start UBI volume update */
#define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t)
/* An eraseblock erasure command, used for debugging, disabled by default */
#define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t)
/* An atomic eraseblock change command */
#define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, int32_t)

/* Maximum MTD device name length supported by UBI */
#define MAX_UBI_MTD_NAME_LEN 127

/*
 * UBI data type hint constants.
 *
 * UBI_LONGTERM: long-term data
 * UBI_SHORTTERM: short-term data
 * UBI_UNKNOWN: data persistence is unknown
 *
 * These constants are used when data is written to UBI volumes in order to
 * help the UBI wear-leveling unit to find more appropriate physical
 * eraseblocks.
 */
enum {
    UBI_LONGTERM = 1,
    UBI_SHORTTERM = 2,
    UBI_UNKNOWN = 3,
};

/*
 * UBI volume type constants.
 *
 * @UBI_DYNAMIC_VOLUME: dynamic volume
 * @UBI_STATIC_VOLUME: static volume
 */
enum {
    UBI_DYNAMIC_VOLUME = 3,
    UBI_STATIC_VOLUME = 4,
};

/**
 * struct ubi_attach_req - attach MTD device request.
 * @ubi_num: UBI device number to create
 * @mtd_num: MTD device number to attach
 * @vid_hdr_offset: VID header offset (use defaults if %0)
 * @padding: reserved for future, not used, has to be zeroed
 *
 * This data structure is used to specify MTD device UBI has to attach and the
 * parameters it has to use. The number which should be assigned to the new UBI
 * device is passed in @ubi_num. UBI may automatically assign the number if
 * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
 * @ubi_num.
 *
 * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
 * offset of the VID header within physical eraseblocks. The default offset is
 * the next min. I/O unit after the EC header. For example, it will be offset
 * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
 * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
 *
 * But in rare cases, if this optimizes things, the VID header may be placed to
 * a different offset. For example, the boot-loader might do things faster if the
 * VID header sits at the end of the first 2KiB NAND page with 4 sub-pages. As
 * the boot-loader would not normally need to read EC headers (unless it needs
 * UBI in RW mode), it might be faster to calculate ECC. This is weird example,
 * but it real-life example. So, in this example, @vid_hdr_offer would be
 * 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
 * aligned, which is OK, as UBI is clever enough to realize this is 4th sub-page
 * of the first page and add needed padding.
 */
struct ubi_attach_req {
    int32_t ubi_num;
    int32_t mtd_num;
    int32_t vid_hdr_offset;
    uint8_t padding[12];
};

/**
 * struct ubi_mkvol_req - volume description data structure used in
 * volume creation requests.
 * @vol_id: volume number
 * @alignment: volume alignment
 * @bytes: volume size in bytes
 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
 * @padding1: reserved for future, not used, has to be zeroed
 * @name_len: volume name length
 * @padding2: reserved for future, not used, has to be zeroed
 * @name: volume name
 *
 * This structure is used by user-space programs when creating new volumes. The
 * @used_bytes field is only necessary when creating static volumes.
 *
 * The @alignment field specifies the required alignment of the volume logical
 * eraseblock. This means, that the size of logical eraseblocks will be aligned
 * to this number, i.e.,
 *    (UBI device logical eraseblock size) mod (@alignment) = 0.
 *
 * To put it differently, the logical eraseblock of this volume may be slightly
 * shortened in order to make it properly aligned. The alignment has to be
 * multiple of the flash minimal input/output unit, or %1 to utilize the entire
 * available space of logical eraseblocks.
 *
 * The @alignment field may be useful, for example, when one wants to maintain
 * a block device on top of an UBI volume. In this case, it is desirable to fit
 * an integer number of blocks in logical eraseblocks of this UBI volume. With
 * alignment it is possible to update this volume using plane UBI volume image
 * BLOBs, without caring about how to properly align them.
 */
struct ubi_mkvol_req {
    int32_t vol_id;
    int32_t alignment;
    int64_t bytes;
    int8_t vol_type;
    int8_t padding1;
    int16_t name_len;
    int8_t padding2[4];
    char name[UBI_MAX_VOLUME_NAME + 1];
} __attribute__ ((packed));

/**
 * struct ubi_rsvol_req - a data structure used in volume re-size requests.
 * @vol_id: ID of the volume to re-size
 * @bytes: new size of the volume in bytes
 *
 * Re-sizing is possible for both dynamic and static volumes. But while dynamic
 * volumes may be re-sized arbitrarily, static volumes cannot be made to be
 * smaller then the number of bytes they bear. To arbitrarily shrink a static
 * volume, it must be wiped out first (by means of volume update operation with
 * zero number of bytes).
 */
struct ubi_rsvol_req {
    int64_t bytes;
    int32_t vol_id;
} __attribute__ ((packed));

/**
 * struct ubi_leb_change_req - a data structure used in atomic logical
 * eraseblock change requests.
 * @lnum: logical eraseblock number to change
 * @bytes: how many bytes will be written to the logical eraseblock
 * @dtype: data type (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN)
 * @padding: reserved for future, not used, has to be zeroed
 */
struct ubi_leb_change_req {
    int32_t lnum;
    int32_t bytes;
    uint8_t dtype;
    uint8_t padding[7];
} __attribute__ ((packed));

#endif /* __UBI_USER_H__ */