|
本帖最后由 raymon 于 2021-1-20 18:43 编辑
static
FRESULT find_volume ( /* FR_OK(0): successful, !=0: any error occurred */
FATFS** rfs, /* Pointer to pointer to the found file system object */
const TCHAR** path, /* Pointer to pointer to the path name (drive number) */
BYTE wmode /* !=0: Check write protection for write access */
)
{
BYTE fmt;
int vol;
DSTATUS stat;
DWORD bsect, fasize, tsect, sysect, nclst, szbfat;
WORD nrsv;
FATFS *fs;
/* Get logical drive number from the path name */
*rfs = 0;
vol = get_ldnumber(path);
if (vol < 0) return FR_INVALID_DRIVE;
/* Check if the file system object is valid or not */
fs = FatFs[vol]; /* Get pointer to the file system object */
if (!fs) return FR_NOT_ENABLED; /* Is the file system object available? */
ENTER_FF(fs); /* Lock the volume */
*rfs = fs; /* Return pointer to the file system object */
if (fs->fs_type) { /* If the volume has been mounted */
stat = disk_status(fs->drv);
if (!(stat & STA_NOINIT)) { /* and the physical drive is kept initialized */
if (!_FS_READONLY && wmode && (stat & STA_PROTECT)) /* Check write protection if needed */
return FR_WRITE_PROTECTED;
return FR_OK; /* The file system object is valid */
}
}
/* The file system object is not valid. */
/* Following code attempts to mount the volume. (analyze BPB and initialize the fs object) */
fs->fs_type = 0; /* Clear the file system object */
fs->drv = LD2PD(vol); /* Bind the logical drive and a physical drive */
stat = disk_initialize(fs->drv); /* Initialize the physical drive */
if (stat & STA_NOINIT) /* Check if the initialization succeeded */
return FR_NOT_READY; /* Failed to initialize due to no medium or hard error */
if (!_FS_READONLY && wmode && (stat & STA_PROTECT)) /* Check disk write protection if needed */
return FR_WRITE_PROTECTED;
#if _MAX_SS != _MIN_SS /* Get sector size (multiple sector size cfg only) */
if (disk_ioctl(fs->drv, GET_SECTOR_SIZE, &SS(fs)) != RES_OK
|| SS(fs) < _MIN_SS || SS(fs) > _MAX_SS) return FR_DISK_ERR;
#endif
/* Find an FAT partition on the drive. Supports only generic partitioning, FDISK and SFD. */
bsect = 0;
fmt = check_fs(fs, bsect); /* Load sector 0 and check if it is an FAT boot sector as SFD */
if (fmt == 1 || (!fmt && (LD2PT(vol)))) { /* Not an FAT boot sector or forced partition number */
UINT i;
DWORD br[4];
for (i = 0; i < 4; i++) { /* Get partition offset */
BYTE *pt = fs->win+MBR_Table + i * SZ_PTE;
br = pt[4] ? LD_DWORD(&pt[8]) : 0;
}
i = LD2PT(vol); /* Partition number: 0:auto, 1-4:forced */
if (i) i--;
do { /* Find an FAT volume */
bsect = br;
fmt = bsect ? check_fs(fs, bsect) : 2; /* Check the partition */
} while (!LD2PT(vol) && fmt && ++i < 4);
}
if (fmt == 3) return FR_DISK_ERR; /* An error occured in the disk I/O layer */
if (fmt) return FR_NO_FILESYSTEM; /* No FAT volume is found */
/* An FAT volume is found. Following code initializes the file system object */
if (LD_WORD(fs->win+BPB_BytsPerSec) != SS(fs)) /* (BPB_BytsPerSec must be equal to the physical sector size) */
return FR_NO_FILESYSTEM;
fasize = LD_WORD(fs->win+BPB_FATSz16); /* Number of sectors per FAT */
if (!fasize) fasize = LD_DWORD(fs->win+BPB_FATSz32);
fs->fsize = fasize;
fs->n_fats = fs->win[BPB_NumFATs]; /* Number of FAT copies */
if (fs->n_fats != 1 && fs->n_fats != 2) /* (Must be 1 or 2) */
return FR_NO_FILESYSTEM;
fasize *= fs->n_fats; /* Number of sectors for FAT area */
fs->csize = fs->win[BPB_SecPerClus]; /* Number of sectors per cluster */
if (!fs->csize || (fs->csize & (fs->csize - 1))) /* (Must be power of 2) */
return FR_NO_FILESYSTEM;
fs->n_rootdir = LD_WORD(fs->win+BPB_RootEntCnt); /* Number of root directory entries */
if (fs->n_rootdir % (SS(fs) / SZ_DIR)) /* (Must be sector aligned) */
return FR_NO_FILESYSTEM;
tsect = LD_WORD(fs->win+BPB_TotSec16); /* Number of sectors on the volume */
if (!tsect) tsect = LD_DWORD(fs->win+BPB_TotSec32);
nrsv = LD_WORD(fs->win+BPB_RsvdSecCnt); /* Number of reserved sectors */
if (!nrsv) return FR_NO_FILESYSTEM; /* (Must not be 0) */
/* Determine the FAT sub type */
sysect = nrsv + fasize + fs->n_rootdir / (SS(fs) / SZ_DIR); /* RSV+FAT+DIR */
if (tsect < sysect) return FR_NO_FILESYSTEM; /* (Invalid volume size) */
nclst = (tsect - sysect) / fs->csize; /* Number of clusters */
if (!nclst) return FR_NO_FILESYSTEM; /* (Invalid volume size) */
fmt = FS_FAT12;
if (nclst >= MIN_FAT16) fmt = FS_FAT16;
if (nclst >= MIN_FAT32) fmt = FS_FAT32;
/* Boundaries and Limits */
fs->n_fatent = nclst + 2; /* Number of FAT entries */
fs->volbase = bsect; /* Volume start sector */
fs->fatbase = bsect + nrsv; /* FAT start sector */
fs->database = bsect + sysect; /* Data start sector */
if (fmt == FS_FAT32) {
if (fs->n_rootdir) return FR_NO_FILESYSTEM; /* (BPB_RootEntCnt must be 0) */
fs->dirbase = LD_DWORD(fs->win+BPB_RootClus); /* Root directory start cluster */
szbfat = fs->n_fatent * 4; /* (Needed FAT size) */
} else {
if (!fs->n_rootdir) return FR_NO_FILESYSTEM; /* (BPB_RootEntCnt must not be 0) */
fs->dirbase = fs->fatbase + fasize; /* Root directory start sector */
szbfat = (fmt == FS_FAT16) ? /* (Needed FAT size) */
fs->n_fatent * 2 : fs->n_fatent * 3 / 2 + (fs->n_fatent & 1);
}
if (fs->fsize < (szbfat + (SS(fs) - 1)) / SS(fs)) /* (BPB_FATSz must not be less than needed) */
return FR_NO_FILESYSTEM;
//此处出现错误
#if !_FS_READONLY
/* Initialize cluster allocation information */
fs->last_clust = fs->free_clust = 0xFFFFFFFF;
/* Get fsinfo if available */
fs->fsi_flag = 0x80;
#if (_FS_NOFSINFO & 3) != 3
if (fmt == FS_FAT32 /* Enable FSINFO only if FAT32 and BPB_FSInfo is 1 */
&& LD_WORD(fs->win+BPB_FSInfo) == 1
&& move_window(fs, bsect + 1) == FR_OK)
{
fs->fsi_flag = 0;
if (LD_WORD(fs->win+BS_55AA) == 0xAA55 /* Load FSINFO data if available */
&& LD_DWORD(fs->win+FSI_LeadSig) == 0x41615252
&& LD_DWORD(fs->win+FSI_StrucSig) == 0x61417272)
{
#if (_FS_NOFSINFO & 1) == 0
fs->free_clust = LD_DWORD(fs->win+FSI_Free_Count);
#endif
#if (_FS_NOFSINFO & 2) == 0
fs->last_clust = LD_DWORD(fs->win+FSI_Nxt_Free);
#endif
}
}
#endif
#endif
fs->fs_type = fmt; /* FAT sub-type */
fs->id = ++Fsid; /* File system mount ID */
#if _FS_RPATH
fs->cdir = 0; /* Set current directory to root */
#endif
#if _FS_LOCK /* Clear file lock semaphores */
clear_lock(fs);
#endif
return FR_OK;
}
有没有大神遇见f->fsize 和 fs->n_fatent 两个不匹配的情况 ,程序红色部分。新卡存在这个问题,SD卡重新格式化下就好了。这句话屏蔽掉,系统也正常,就是不知道稳定性咋样。 |
阿莫论坛20周年了!感谢大家的支持与爱护!!
一只鸟敢站在脆弱的枝条上歇脚,它依仗的不是枝条不会断,而是自己有翅膀,会飞。
|