virpartff.c

/*
 * Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
 * Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 *    conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list
 *    of conditions and the following disclaimer in the documentation and/or other materials
 *    provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used
 *    to endorse or promote products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "ffconf.h"
#include "virpartff.h"
#include "string.h"
#include "diskio.h"

#ifdef LOSCFG_FS_FAT_VIRTUAL_PARTITION

#if FF_USE_LFN == 0 /* Non-LFN configuration */
#define DEF_NAMBUF
#define INIT_NAMBUF(fs)
#define FREE_NAMBUF()

#else /* LFN configuration */
#if (FF_MAX_LFN < 12) || (FF_MAX_LFN > 255)
#error Wrong _MAX_LFN value
#endif

#if FF_USE_LFN == 1 /* LFN enabled with static working buffer */
static WCHAR g_lfnBuf[FF_MAX_LFN + 1]; /* LFN enabled with static working buffer */
#define DEF_NAMBUF
#define INIT_NAMBUF(fs)
#define FREE_NAMBUF()

#elif FF_USE_LFN == 2 /* LFN enabled with dynamic working buffer on the stack */
#define DEF_NAMBUF      WCHAR lbuf[FF_MAX_LFN + 1];
#define INIT_NAMBUF(fs) { (fs)->lfnbuf = lbuf; }
#define FREE_NAMBUF()

#elif FF_USE_LFN == 3 /* LFN enabled with dynamic working buffer on the heap */
#define DEF_NAMBUF      WCHAR *lfn;
#define INIT_NAMBUF(fs) { lfn = ff_memalloc((FF_MAX_LFN + 1) * 2); if (!lfn) LEAVE_FF(fs, FR_NOT_ENOUGH_CORE); (fs)->lfnbuf = lfn; }
#define FREE_NAMBUF()   ff_memfree(lfn)

#else
#error Wrong FF_USE_LFN setting

#endif
#endif /* else FF_USE_LFN == 0 */


#if FF_FS_REENTRANT
#if FF_USE_LFN == 1
#error Static LFN work area cannot be used at thread-safe configuration
#endif
#define ENTER_FF(fs)        do { if (!lock_fs(fs)) return FR_TIMEOUT; } while (0)
#define LEAVE_FF(fs, res)   do { unlock_fs(fs, res); return res; } while (0)
#else
#define ENTER_FF(fs)
#define LEAVE_FF(fs, res) return (res)
#endif

extern FATFS *FatFs[FF_VOLUMES];

/*
* follow_virentry:
* Compare the top segment with the virtual partition entry and replace it to its CHILD FATFS
*
* Acceptable return vaule:
* - FR_OK      : The top segment matches one of the virtual partition entries, and the FATFS
*              has been replaced to the corresponding FATFS.
* - FR_DENIED  : The top segment does not matched any of the virtual partition entries, and
*              the FATFS has kept as it is. Or the virtual partition feature has been
*              switched down by any reason.
* - FR_INT_ERR : Assertion error
*/
FRESULT follow_virentry(FFOBJID *obj, const TCHAR *path)
{
    TCHAR keyword[FF_MAX_LFN + 1] = {0};
    FATFS *fs = obj->fs;
    INT len;
    UINT i;

    (void)memset_s(keyword, sizeof(keyword), 0, sizeof(keyword));
    /* Search and copy the first segment in path */
    for (len = 0; *path != '/' && *path != '\\' && *path != '\0' && len < FF_MAX_LFN; path++, len++) {
        keyword[len] = *path;
    }

    if (len == 0 || len > _MAX_ENTRYLENGTH) {
        return FR_DENIED;
    }

    /*
    * Compare the segment does match one for virtual partitions' entry or not,
    * replace the FATFS if the result is positive
    */
    for (i = 0; i < fs->vir_amount; i++) {
        if (!CHILDFS(fs, i)) {
            return FR_INT_ERR;
        }
        if (memcmp((CHILDFS(fs, i))->namelabel, keyword, _MAX_ENTRYLENGTH + 1) == 0) {
            obj->fs = CHILDFS(fs, i);
            return FR_OK;
        }
    }

    return FR_DENIED;
}

FRESULT f_checkname(const TCHAR *path)
{
    FRESULT res;
    DIR dj;
    FATFS fs;
    TCHAR *label = (TCHAR *)path;
    DEF_NAMBUF

    (void)memset_s(&fs, sizeof(fs), 0, sizeof(fs));
    dj.obj.fs = &fs;
    INIT_NAMBUF(&fs);
    res = create_name(&dj, &path);
    /* the last byte of file name can't be a space */
    if (res == FR_OK && dj.fn[11] == 0x20) {
        res = FR_INVALID_NAME;
        return res;
    }

    FREE_NAMBUF();

    for (; *label != '\0'; label++) {
        if (label - path > _MAX_ENTRYLENGTH) {
            res = FR_INVALID_NAME;
            return res;
        }
        if (*label == '/' || *label == '\\') {
            res = FR_INVALID_NAME;
            return res;
        }
    }
    return res;
}

FATFS *f_getfatfs(int vol)
{
    FATFS *fs = NULL;
    if (vol < 0 || vol >= FF_VOLUMES) {
        fs = NULL;
    } else {
        fs = FatFs[vol];
    }
    return fs;
}

static FRESULT FatfsCheckBoundParam(FATFS *fs, DWORD clust)
{
    if (fs->st_clst <= 2 || (fs->st_clst + fs->ct_clst) > fs->n_fatent) {
        return FR_INT_ERR;
    }
    if (clust < 2 || clust > fs->n_fatent) {
        return FR_INT_ERR;
    }
    if (clust >= (fs->st_clst + fs->ct_clst) || clust < fs->st_clst) {
        return FR_CHAIN_ERR;
    }

    return FR_OK;
}

/*
* check_boundary:
* Check the chain occupied more than one virtual partition or not start at the var 'clust'
*
* Acceptable Return Value:
* - FR_OK          : The chain occupied only one virtual parition
* - FR_CHAIN_ERR   : The chain occupied more than one virtual parition
*/
FRESULT f_boundary(FATFS *fs, DWORD clust)
{
    FFOBJID obj;
    FRESULT res;
    obj.fs = fs;
    if (fs == NULL) {
        return FR_INT_ERR;
    }
    if (fs->fs_type != FS_FAT32) {
        return FR_INVAILD_FATFS;
    }
    ENTER_FF(fs);

    res = FatfsCheckBoundParam(fs, clust);
    if (res != FR_OK) {
        LEAVE_FF(fs, res);
    }
    for (;;) {
        clust = get_fat(&obj, clust);
        if (clust == 0xFFFFFFFF) {
            LEAVE_FF(fs, FR_DISK_ERR);
        }
        if (clust == 0x0FFFFFFF) {
            break;
        }
        if (clust < 2 || clust >= fs->n_fatent) {
            LEAVE_FF(fs, FR_INT_ERR);
        }
        if (clust >= (fs->st_clst + fs->ct_clst) || clust < fs->st_clst) {
            LEAVE_FF(fs, FR_CHAIN_ERR);
        }
    }

    LEAVE_FF(fs, FR_OK);
}

/*
* f_unregvirfs:
* Uninitialized the CHILD FATFS object
*
* Acceptable Return Value:
* - FR_OK : Successfully initialized the CHILD FATFS object.
*/
FRESULT f_disvirfs(FATFS *fs)
{
    if (ISCHILD(fs)) {
        return FR_INVAILD_FATFS;
    }

    if (fs->vir_amount > _MAX_VIRVOLUMES) {
        return FR_INT_ERR;
    }

    ENTER_FF(fs);

    (void)f_unregvirfs(fs);
    LEAVE_FF(fs, FR_OK);
}

FRESULT f_unregvirfs(FATFS *fs)
{
    UINT i;

    if (fs == NULL || ISCHILD(fs)) {
        return FR_INVAILD_FATFS;
    }

    fs->vir_avail = FS_VIRDISABLE;
    /* PARENT FATFS has linked to CHILD FATFS already */
    if (fs->child_fs != NULL) {
        /* Followed the CHILD FATFS and free the memory */
        for (i = 0; i < fs->vir_amount; i++) {
            if (CHILDFS(fs, i) != NULL) {
                ff_memfree(CHILDFS(fs, i));
            }
        }
        /* Free the 'child_fs' feild */
        ff_memfree(fs->child_fs);
        fs->child_fs = NULL;
        fs->vir_amount = 0xFFFFFFFF;
    }

    return FR_OK;
}

static void FatfsSetParentFs(FATFS *pfs, FATFS *fs)
{
    pfs->fs_type = fs->fs_type; /* Copy the feild info from PARENT FATFS object */
    pfs->pdrv = fs->pdrv;
    pfs->n_fats = fs->n_fats;
    pfs->id = fs->id;
    pfs->n_rootdir = fs->n_rootdir;
    pfs->csize = fs->csize;
#if FF_MAX_SS != FF_MIN_SS
    pfs->ssize = fs->ssize;
#endif
    pfs->sobj = fs->sobj;

#if FF_FS_RPATH != 0
    pfs->cdir = 0;
#endif
    pfs->n_fatent = fs->n_fatent;
    pfs->fsize = fs->fsize;
    pfs->volbase = fs->volbase;
    pfs->fatbase = fs->fatbase;
    pfs->dirbase = fs->dirbase;
    pfs->database = fs->database;
    pfs->last_clst = 0xFFFFFFFF; /* Mark the 'last_clst' and 'free_clst' in CHILD FATFS is not been updated for now */
    pfs->free_clst = 0xFFFFFFFF;
    pfs->st_clst = 0xFFFFFFFF; /* Mark the 'st_clst' and 'ct_clst' in CHILD FATFS is not been update for now. */
    pfs->ct_clst = 0xFFFFFFFF;
    pfs->vir_flag = FS_CHILD; /* Mark the FATFS object is a CHILD */
    pfs->vir_avail = FS_VIRENABLE; /* Mark the CHILD object is enable for now */
    pfs->parent_fs = (void *)fs; /* Link to the PARENT object */
    pfs->child_fs = (void *)NULL; /* Link the unrelated feild to NULL */
}

/*
* f_regvirfs:
* Initialized the CHILD FATFS object
*
* Acceptable Return Value:
* - FR_OK : Successfully initialized the CHILD FATFS object.
*
* Others Return Value:
* - FR_INVAILD_FATFS       :   The FATFS object has error or the info in it has been occuried
* - FR_DENIED              :   The virtual partition feature has been shut down by switcher
* - FR_DISK_ERR            :   A disk error happened
* - FR_NOT_ENOUGH_CORE     :   Not enough memory for allocate space for CHILD FATFS
* - FR_INVALID_PARAMETER   :   There is a invaild value in current setting
*/
FRESULT f_regvirfs(FATFS *fs)
{
    UINT i;
    FATFS *pfs = NULL;

    if (fs == NULL || ISCHILD(fs)) {
        return FR_INVAILD_FATFS;
    }

    if (fs->vir_amount > _MAX_VIRVOLUMES) {
        return FR_INT_ERR;
    }

    fs->parent_fs = (void *)fs; /* Relink to itself */
    /* Mark the FATFS object is PARENT */
    fs->st_clst = 0xFFFFFFFF;
    fs->ct_clst = 0xFFFFFFFF;
    /* Allocate a space for linking to the child FATFS */
    fs->child_fs = (void **)ff_memalloc(fs->vir_amount * sizeof(void *));
    if (fs->child_fs == NULL) {
        return FR_NOT_ENOUGH_CORE;
    }
    fs->vir_avail = FS_VIRENABLE; /* Mark the PARENT object is enable for now */

    /* Set the CHILD object field */
    for (i = 0; i < fs->vir_amount; i++) {
        pfs = ff_memalloc(sizeof(FATFS)); /* Allocate a memeory for current child FATFS object */
        if (pfs == NULL) { /* If allocate failed, must call 'f_unregvirfs' to free the previous FATFS object memory */
            goto ERROUT;
        }
        FatfsSetParentFs(pfs, fs);
        *(fs->child_fs + i) = (void *)pfs;
    }

    return FR_OK;
ERROUT:
    while (i > 0) {
        --i;
        ff_memfree(*(fs->child_fs + i));
    }
    ff_memfree(fs->child_fs);
    fs->child_fs = NULL;

    return FR_NOT_ENOUGH_CORE;
}

static FRESULT FatfsCheckScanFatParam(FATFS *fs)
{
    if (fs == NULL) {
        return FR_INVAILD_FATFS;
    }

    if (ISNORMAL(fs)) {
        return FR_DENIED;
    }

    if (fs->fs_type != FS_FAT32 || ISPARENT(fs)) {
        return FR_INVAILD_FATFS;
    }

    if (fs->st_clst < 3 || fs->st_clst >= fs->n_fatent) {
        return FR_INVAILD_FATFS;
    }

    if (fs->ct_clst == 0 || fs->ct_clst > (fs->n_fatent - 3)) {
        return FR_INVAILD_FATFS;
    }

    if ((fs->st_clst + fs->ct_clst) > fs->n_fatent || (fs->st_clst + fs->ct_clst) < 3) {
        return FR_INVAILD_FATFS;
    }

    return FR_OK;
}

/*
* f_scanfat:
* Scan the FAT inside the boundary of CHILD FATFS limit, and update the free cluster and last cluster
*
* Acceptable Return Value:
* - FR_OK : Successfully scaned the FAT and update field.
*
* Others Return Value:
* - FR_INVAILD_FATFS   :   The FATFS object has error or the info in it has been occuried
* - FR_DENIED          :   The virtual partition feature has been shut down by switcher
* - FR_DISK_ERR        :   A disk error happened
*/
FRESULT f_scanfat(FATFS *fs)
{
    FRESULT res;
    DWORD clst;
    DWORD link;
    FFOBJID obj;

    res = FatfsCheckScanFatParam(fs);
    if (res != FR_OK) {
        return res;
    }

    ENTER_FF(fs);
    res = FR_OK;
    obj.fs = fs;

    fs->free_clst = fs->ct_clst;
    for (clst = fs->st_clst; clst < fs->st_clst + fs->ct_clst; clst++) {
        link = get_fat(&obj, clst);
        if (link == 0xFFFFFFFF) {
            LEAVE_FF(fs, FR_DISK_ERR);
        }
        if (link == 0) {
            continue;
        }
        fs->free_clst--;
    }
    fs->last_clst = fs->st_clst - 1;

    LEAVE_FF(fs, res);
}

static FRESULT FatfsCheckStart(BYTE *work, FATFS *fs, BYTE vol)
{
    DWORD startBaseSect, countBaseSect;

    countBaseSect = LD2PC(vol); /* Volume Base Sectors Count */
    startBaseSect = LD2PS(vol); /* Volume Base Start Sector */

    /* Check ASCII for Keyword "LITE" */
    if (ld_dword(work + VR_VertifyString) != 0x4C495445) {
        return FR_NOVIRPART;
    }
    /* Check whether filesystem has been changed or not */
    if (work[VR_PartitionFSType] != fs->fs_type) {
        return FR_MODIFIED;
    }
    /* Check whether volume base sector has benn changed or not */
    if (ld_dword(work + VR_PartitionStSec) != startBaseSect) {
        return FR_MODIFIED;
    }
    /* Check whether volume base size hase been changed or not */
    if (ld_dword(work + VR_PartitionCtSec) != countBaseSect) {
        return FR_MODIFIED;
    }
    /* Check whether volume cluster size has been changed or not */
    if (ld_word(work + VR_PartitionClstSz) != fs->csize) {
        return FR_MODIFIED;
    }
    /* Check whether volume start cluster is cluster #3 or not */
    if (ld_dword(work + VR_PartitionCtClst) != fs->n_fatent) {
        return FR_MODIFIED;
    }
    /* Check whether virtual partition overlimit */
    if (work[VR_PartitionCnt] > _MAX_VIRVOLUMES) {
        return FR_MODIFIED;
    }

    return FR_OK;
}

static FRESULT FatfsCheckPercent(FATFS *fs, WORD i)
{
    if ((CHILDFS(fs, i))->st_clst + (CHILDFS(fs, i))->ct_clst < fs->n_fatent) {
        fs->st_clst = (CHILDFS(fs, i))->st_clst + (CHILDFS(fs, i))->ct_clst;
        fs->ct_clst = fs->n_fatent - ((CHILDFS(fs, i))->st_clst + (CHILDFS(fs, i))->ct_clst);
    } else if ((CHILDFS(fs, i))->st_clst + (CHILDFS(fs, i))->ct_clst == fs->n_fatent) {
        fs->st_clst = 0xFFFFFFFF;
        fs->ct_clst = 0xFFFFFFFF;
    } else {
        (void)f_unregvirfs(fs);
        return FR_MODIFIED;
    }

    return FR_OK;
}

static FRESULT FatfsCheckPartClst(FATFS *fs, WORD i)
{
    if (i == 0) {
        /* First virtual partition must start at cluster #3 */
        if ((CHILDFS(fs, i))->st_clst != 3) {
            (void)f_unregvirfs(fs);
            return FR_MODIFIED;
        }
    } else {
        /* Check whether the current virtual partition is closely next to the previous virtual partition */
        if ((CHILDFS(fs, i))->st_clst != (CHILDFS(fs, (i - 1))->st_clst + CHILDFS(fs, (i - 1))->ct_clst)) {
            (void)f_unregvirfs(fs);
            return FR_MODIFIED;
        }
    }

    return FR_OK;
}

static void FatfsSetChildClst(BYTE *work, FATFS *fs, WORD i)
{
    (CHILDFS(fs, i))->st_clst = ld_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_StartClust);
    (CHILDFS(fs, i))->ct_clst = ld_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_CountClust);
}

/*
* f_ckvtlpt :
* Check the external SD virtual paritition sectors and read configure from it
*
* Acceptable Return Value:
* - FR_OK          : The external SD configure is complete, all info has been set to the
*                  each CHILD FATFS
* - FR_NOT_MATCHED : The virtual partition's configure does not matched as current setting
* - FR_MODIFIED    : The virtual partition's configure has been destoried partly or completely
* - FR_NOVIRPART   : The external SD has not been apllied as virtual partition yet
*
* Others Return Value:
* - FR_INVAILD_FATFS : The FATFS object has error or the info in it has been occuried
* - FR_DENIED          : The virtual partition feature has been shut down by switcher
* - FR_INVALID_DRIVE   : The drive index is error
* - FR_DISK_ERR        : A Disk error happend
*/
FRESULT f_checkvirpart(FATFS *fs, const TCHAR *path, BYTE vol)
{
    FRESULT res;
    WORD i;
    DWORD virSect;
    DWORD tmp;
    BYTE pdrv;
    BYTE *work = NULL;
    CHAR label[_MAX_ENTRYLENGTH + 1];
    DWORD *labelTmp = NULL; /* to clear the compilation warning */

    if (fs == NULL || (disk_status(fs->pdrv) & STA_NOINIT)) {
        return FR_INVAILD_FATFS; /* The object is invalid */
    }

    /* Lock the filesystem object */
    res = find_volume(&path, &fs, FA_WRITE); /* Update the filesystem info to the parent fs */
    if (res != FR_OK) {
        LEAVE_FF(fs, res);
    }

    if (ISCHILD(fs)) {
        LEAVE_FF(fs, FR_INT_ERR);
    }
    /* Data will be save at the last reserve sector ,which is the front one of the fat base sector */
    virSect = fs->fatbase - 1;

    pdrv = LD2PD(vol); /* Driver index */

    work = (BYTE *)ff_memalloc(SS(fs));
    if (work == NULL) {
        LEAVE_FF(fs, FR_NOT_ENOUGH_CORE);
    }
    /* Check and vertify partition information */
    if (disk_read(pdrv, work, virSect, 1) != RES_OK) {
        res = FR_DISK_ERR;
        goto EXIT;
    } /* Load VBR */

    res = FatfsCheckStart(work, fs, vol);
    if (res != FR_OK) {
        goto EXIT;
    }
    /* Check the virtual parition amount if matched current setting or not */
    fs->vir_amount = work[VR_PartitionCnt];
    res = f_regvirfs(fs);
    if (res != FR_OK) {
        goto EXIT;
    }

    for (i = 0; i < _MAX_VIRVOLUMES; i++) {
        if (i < work[VR_PartitionCnt]) {
            if (work[VR_PARTITION + i * VR_ITEMSIZE + VR_Available] != 0x80) {
                (void)f_unregvirfs(fs);
                res = FR_MODIFIED;
                goto EXIT;
            }
        } else {
            if (work[VR_PARTITION + i * VR_ITEMSIZE + VR_Available] != 0x00) {
                (void)f_unregvirfs(fs);
                res = FR_MODIFIED;
                goto EXIT;
            }
            break;
        }

        (void)memset_s(label, sizeof(label), 0, sizeof(label));

        tmp = ld_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_Entry + 0);
        labelTmp = (DWORD *)label;
        *labelTmp = tmp;
        tmp = ld_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_Entry + 4);
        *((DWORD * )(label + 4)) = tmp;
        tmp = ld_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_Entry + 8);
        *((DWORD * )(label + 8)) = tmp;
        tmp = ld_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_Entry + 12);
        *((DWORD * )(label + 12)) = tmp;

        if (f_checkname(label) != FR_OK) {
            (void)f_unregvirfs(fs);
            res = FR_MODIFIED;
            goto EXIT;
        }
        (void)memcpy_s((CHILDFS(fs, i))->namelabel, _MAX_ENTRYLENGTH + 1, label, _MAX_ENTRYLENGTH + 1);

        FatfsSetChildClst(work, fs, i);

        /* External SD setting has overlimit the whole partition cluster amount */
        if ((QWORD)(CHILDFS(fs, i))->st_clst + (QWORD)((CHILDFS(fs, i))->ct_clst) > (QWORD)fs->n_fatent) {
            (void)f_unregvirfs(fs);
            res = FR_MODIFIED;
            goto EXIT;
        }

        res = FatfsCheckPartClst(fs, i);
        if (res != FR_OK) {
            goto EXIT;
        }
        if (i == (work[VR_PartitionCnt] - 1)) {
            /*
             * If the external SD virtual partition percent exceeds the error tolerance based on current virtual
             * partition percent setting
             */
            res = FatfsCheckPercent(fs, i);
            if (res != FR_OK) {
                goto EXIT;
            }
        }
    }
EXIT:
    ff_memfree(work);
    LEAVE_FF(fs, res);
}

static void FatfsClacPartInfo(FATFS *fs, DOUBLE virpartper, UINT i)
{
    if (i == 0) {
        (CHILDFS(fs, i))->st_clst = 3;
        (CHILDFS(fs, i))->ct_clst = (DWORD)((fs->n_fatent - 3) *
                                            g_fatVirPart.virtualinfo.virpartpercent[i]);

        fs->st_clst = (CHILDFS(fs, i))->st_clst + (CHILDFS(fs, i))->ct_clst;
        fs->ct_clst = fs->n_fatent - fs->st_clst;
    } else if (i != (fs->vir_amount - 1)) {
        (CHILDFS(fs, i))->st_clst = (CHILDFS(fs, (i - 1)))->st_clst + (CHILDFS(fs, (i - 1)))->ct_clst;
        (CHILDFS(fs, i))->ct_clst = (DWORD)((fs->n_fatent - 3) *
                                            g_fatVirPart.virtualinfo.virpartpercent[i]);
    } else {
        (CHILDFS(fs, i))->st_clst = (CHILDFS(fs, (i - 1)))->st_clst + (CHILDFS(fs, (i - 1)))->ct_clst;
        if (virpartper <= (1 + _FLOAT_ACC) && virpartper >= (1 - _FLOAT_ACC)) {
            (CHILDFS(fs, i))->ct_clst = fs->n_fatent - (CHILDFS(fs, i))->st_clst;
            fs->st_clst = 0xFFFFFFFF;
            fs->ct_clst = 0xFFFFFFFF;
        } else {
            (CHILDFS(fs, i))->ct_clst = (DWORD)((fs->n_fatent - 3) *
                                                g_fatVirPart.virtualinfo.virpartpercent[i]);
            fs->st_clst = (CHILDFS(fs, i))->st_clst + (CHILDFS(fs, i))->ct_clst;
            fs->ct_clst = fs->n_fatent - fs->st_clst;
        }
    }
}

/*
* f_mkvtlpt:
* Apply the current virtual partition's setting to external SD card and to the CHILD FATFS
*
* Acceptable Return Value:
* - FR_OK : Successfully applied current setting to external SD card and
*              CHILD FATFS
*
* Others Return Value  :
* - FR_INVAILD_FATFS   : The FATFS object has error or the info in it has been occuried
* - FR_DENIED          : The virtual partition feature has been shut down by switcher
* - FR_INVALID_DRIVE   : The drive index is error
* - FR_DISK_ERR        : A Disk error happend
*/
FRESULT f_makevirpart(FATFS *fs, const TCHAR *path, BYTE vol)
{
    FRESULT res;
    DWORD virSect;
    DWORD startBaseSect, countBaseSect;
    DWORD tmp;
    CHAR label[_MAX_ENTRYLENGTH + 1];
    DWORD *labelTmp = NULL; /* to clear the compilation warning */
    UINT i;
    BYTE pdrv;
    BYTE *work = NULL;
    DOUBLE virpartper = 0.0;

    if (fs == NULL || (disk_status(fs->pdrv) & STA_NOINIT)) {
        return FR_INVAILD_FATFS; /* The object is invalid */
    }

    /* Lock the filesystem object */
    res = find_volume(&path, &fs, FA_WRITE); /* Update the filesystem info to the parent fs */
    if (res != FR_OK) {
        LEAVE_FF(fs, res);
    }

    /* Only available in FAT32 filesystem */
    if (ISCHILD(fs)) {
        LEAVE_FF(fs, FR_INVAILD_FATFS);
    }
    /* Data will be save at the last reserve sector,which is the front one of the fat base sector */
    virSect = fs->fatbase - 1;
    /* Search the fs index, which same as the volume index */
    pdrv = LD2PD(vol); /* Driver index */
    countBaseSect = LD2PC(vol); /* Volume Base Sectors Count */
    startBaseSect = LD2PS(vol); /* Volume Base Start Sector */

    fs->vir_amount = g_fatVirPart.virtualinfo.virpartnum;
    res = f_regvirfs(fs);
    if (res != FR_OK) {
        LEAVE_FF(fs, res);
    }

    work = (BYTE *)ff_memalloc(SS(fs));
    if (work == NULL) {
        LEAVE_FF(fs, FR_NOT_ENOUGH_CORE);
    }
    /* Data Cluster is begin from the Cluster #3 to the last cluster */
    /* Cluster #0 #1 is for VBR, reserve sectors and fat */
    /* Cluster #2 is for root directory */
    (void)memset_s(work, SS(fs), 0, SS(fs));

    for (i = 0; i < fs->vir_amount; i++) {
        /* Copy the Entry label and write to work sector's buffer */
        (void)memset_s(label, sizeof(label), 0, sizeof(label));
        (void)memcpy_s(label, _MAX_ENTRYLENGTH + 1, g_fatVirPart.virtualinfo.virpartname[i], _MAX_ENTRYLENGTH + 1);
        labelTmp = (DWORD *)label;
        tmp = *labelTmp;
        st_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_Entry + 0, tmp);
        tmp = *((DWORD * )(label + 4));
        st_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_Entry + 4, tmp);
        tmp = *((DWORD * )(label + 8));
        st_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_Entry + 8, tmp);
        tmp = *((DWORD * )(label + 12));
        st_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_Entry + 12, tmp);

        virpartper += g_fatVirPart.virtualinfo.virpartpercent[i];

        (void)memcpy_s((CHILDFS(fs, i))->namelabel, _MAX_ENTRYLENGTH + 1, g_fatVirPart.virtualinfo.virpartname[i],
                       _MAX_ENTRYLENGTH + 1);
        FatfsClacPartInfo(fs, virpartper, i);
        (CHILDFS(fs, i))->last_clst = (CHILDFS(fs, i))->st_clst - 1;
        work[VR_PARTITION + i * VR_ITEMSIZE + VR_Available] = 0x80;
    }

    /* Set the data to sector */
    work[VR_PartitionCnt] = fs->vir_amount;
    work[VR_PartitionFSType] = fs->fs_type;
    st_dword(work + VR_PartitionStSec, startBaseSect);
    st_dword(work + VR_PartitionCtSec, countBaseSect);
    st_word(work + VR_PartitionClstSz, fs->csize);
    st_dword(work + VR_PartitionCtClst, fs->n_fatent);
    for (i = 0; i < fs->vir_amount; i++) {
        st_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_StartClust,
                 (CHILDFS(fs, i))->st_clst);
        st_dword(work + VR_PARTITION + i * VR_ITEMSIZE + VR_CountClust,
                 (CHILDFS(fs, i))->ct_clst);
    }

    /* ASCII for Keyword "LITE" */
    st_dword(work + VR_VertifyString, 0x4C495445);

    /* Write into the data area */
    if (disk_write(pdrv, work, virSect, 1) != RES_OK) {
        (void)f_unregvirfs(fs);
        res = FR_DISK_ERR;
    }

    ff_memfree(work);
    LEAVE_FF(fs, res);
}

FRESULT f_getvirfree(const TCHAR *path, DWORD *nclst, DWORD *cclst)
{
    FATFS *fs = NULL;
    FRESULT res;
    DWORD clst, link;
    DWORD nfree;
    UINT i;
    DIR dj;

    /* Find volume to Update the global FSINFO */
    res = find_volume(&path, &fs, 0);
    if (res != FR_OK) {
        LEAVE_FF(fs, res);
    }

    /* Following the entry keyword, decide to replace the PARENT FATFS to CHILD FATFS or not */
    dj.obj.fs = fs;
    if (ISVIRPART(fs)) {
        /* Check the virtual partition top directory, and match the virtual fs */
        res = follow_virentry(&dj.obj, path);
        if (res == FR_INT_ERR) {
            LEAVE_FF(fs, res);
        }
        if (res == FR_OK) {
            fs = dj.obj.fs;
        }
    } else {
        /* Virtual Partition Feature was off, deny this operation */
        LEAVE_FF(fs, FR_DENIED);
    }

    /* If current FATFS is a CHILD FATFS */
    if (ISCHILD(fs)) {
        /* If CHILD FATFS' free_clst is invaild, the scan the FAT and update it */
        if (fs->free_clst > fs->ct_clst) {
            dj.obj.fs = fs;
            fs->free_clst = fs->ct_clst;
            for (clst = fs->st_clst; clst < fs->st_clst + fs->ct_clst; clst++) {
                link = get_fat(&dj.obj, clst);
                if (link == 0) {
                    continue;
                }
                fs->free_clst--;
            }
        }
        *nclst = fs->free_clst;
        *cclst = fs->ct_clst;
        LEAVE_FF(fs, FR_OK);
    } else {
        nfree = 0;
        if (fs->ct_clst == 0xFFFFFFFF) {
            LEAVE_FF(fs, FR_DENIED);
        }
        for (i = 0; i < fs->vir_amount; i++) {
            if (CHILDFS(fs, i)->free_clst > CHILDFS(fs, i)->ct_clst) {
                dj.obj.fs = CHILDFS(fs, i);
                CHILDFS(fs, i)->free_clst = CHILDFS(fs, i)->ct_clst;
                for (clst = CHILDFS(fs, i)->st_clst; clst < CHILDFS(fs, i)->st_clst + CHILDFS(fs, i)->ct_clst; clst++) {
                    link = get_fat(&dj.obj, clst);
                    if (link == 0) {
                        continue;
                    }
                    CHILDFS(fs, i)->free_clst--;
                }
            }
            nfree += CHILDFS(fs, i)->free_clst;
        }
        *nclst = fs->free_clst - nfree;
        *cclst = fs->ct_clst;
        LEAVE_FF(fs, FR_OK);
    }
}
#endif