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  • fatfs文件系统详解之f_mount函数分析

    千次阅读 2020-05-23 19:33:37
    前序 上一篇分析了格式化一个磁盘的时候发生了什么,在格式化一个...f_mount()函数全部代码 为了方便分析,排除视觉障碍,已经删除了不在假设范围内代码。 /*----------------------------------------------..

    前序

    上一篇分析了格式化一个磁盘的时候发生了什么,在格式化一个磁盘之后,就要将磁盘进行挂载,“挂载”这个词听起来很抽象,但是在软件代码上,到底发生了什么?

     

    分析假设

    (1)假设一个磁盘就一个分区。

    (2)只分析FAT32文件系统相关的代码。

    (3)函数的大部分分析,都写入代码注释中

     

    f_mount()函数全部代码

    为了方便分析,排除视觉障碍,已经删除了不在假设范围内代码。

    FRESULT f_mount (
    	FATFS* fs,			/* fat文件系统描述的一个结构体,需要用户进行分配,然后会被记录在全局的FATFS[]这个数组中 */
    	const TCHAR* path,	/* 物理磁盘 */
    	BYTE opt			/* 挂载选项,1-代表立马挂载,从代码分析中知,这个值必须传入1 */
    )
    {
    	FATFS *cfs;
    	int vol;
    	FRESULT res;
    	const TCHAR *rp = path;
    
    
    	/* 获取驱动号,为了找到FatFs[]数组中的空闲项 */
    	vol = get_ldnumber(&rp);
    	if (vol < 0) return FR_INVALID_DRIVE;
    	cfs = FatFs[vol];					/* Pointer to fs object */
    
    	if (cfs) {
    #if _FS_LOCK != 0
    		clear_lock(cfs);
    #endif
    #if _FS_REENTRANT						/* Discard sync object of the current volume */
    		if (!ff_del_syncobj(cfs->sobj)) return FR_INT_ERR;
    #endif
    		cfs->fs_type = 0;				/* Clear old fs object */
    	}
    
    	if (fs) {
    		fs->fs_type = 0;				/* Clear new fs object */
    #if _FS_REENTRANT						/* Create sync object for the new volume */
    		if (!ff_cre_syncobj((BYTE)vol, &fs->sobj)) return FR_INT_ERR;
    #endif
    	}
    
        /* 把用户分配的FATFS结构图放入全局数组指针中 */
    	FatFs[vol] = fs;					/* Register new fs object */
    
    	if (!fs || opt != 1) return FR_OK;	/* Do not mount now, it will be mounted later */
        
        /* 这个函数才是挂载时的关键所在 */
    	res = find_volume(&path, &fs, 0);	/* Force mounted the volume */
    	LEAVE_FF(fs, res);
    }
    

    从f_mount函数分析中可知,find_volume()函数才是挂载的核心代码,

    
    static
    FRESULT find_volume (	/* FR_OK(0): successful, !=0: any error occurred */
    	const TCHAR** path,	/* 硬件磁盘,与f_mount函数的参数是一致的 */
    	FATFS** rfs,		/* 与f_mount函数的fs参数是一致的 */
    	BYTE mode			/* 这个传入的是0 */
    )
    {
    	BYTE fmt, *pt;
    	int vol;
    	DSTATUS stat;
    	DWORD bsect, fasize, tsect, sysect, nclst, szbfat, br[4];
    	WORD nrsv;
    	FATFS *fs;
    	UINT i;
    
    
    	/* Get logical drive number */
    	*rfs = 0;
    	vol = get_ldnumber(path);
    	if (vol < 0) return FR_INVALID_DRIVE;
    
    	/* Check if the file system object is valid or not */
        /* 1.找到用户分配的FATFS结构体 */
    	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 */
    
    	mode &= (BYTE)~FA_READ;				/* Desired access mode, write access or not */
    
        /* 判定磁盘当前状态,如果磁盘被初始化过,那么就判定是挂载过了,直接返回OK */
    	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 && mode && (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) */
    
        /* 2.进行FATFS结构体填充 */
    	fs->fs_type = 0;					/* Clear the file system object */
    	fs->drv = LD2PD(vol);				/* Bind the logical drive and a physical drive */
    
        /* 2.1初始化磁盘 */
    	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 && mode && (stat & STA_PROTECT)) { /* Check disk write protection if needed */
    		return FR_WRITE_PROTECTED;
    	}
    	/* Find an FAT partition on the drive. Supports only generic partitioning, FDISK and SFD. */
    	bsect = 0;
    
        /* 2.2 check_fs()函数会把磁盘的第1个扇区(就是MBR)读入到fs->win[]数组中, 判断MBR是否是合法的MBR*/
    	fmt = check_fs(fs, bsect);			/* Load sector 0 and check if it is an FAT-VBR as SFD */
    
        /* 2.3 fmt=0,说明是FAT32文件系统 */
    	if (fmt == 2 || (fmt < 2 && LD2PT(vol) != 0)) {	/* Not an FAT-VBR or forced partition number */
    		for (i = 0; i < 4; i++) {			/* Get partition offset */
    			pt = fs->win + (MBR_Table + i * SZ_PTE);
    			br[i] = pt[PTE_System] ? ld_dword(pt + PTE_StLba) : 0;
    		}
    		i = LD2PT(vol);						/* Partition number: 0:auto, 1-4:forced */
    		if (i) i--;
    		do {								/* Find an FAT volume */
    			bsect = br[i];
    			fmt = bsect ? check_fs(fs, bsect) : 3;	/* Check the partition */
    		} while (!LD2PT(vol) && fmt >= 2 && ++i < 4);
    	}
    	if (fmt == 4) return FR_DISK_ERR;		/* An error occured in the disk I/O layer */
    	if (fmt >= 2) return FR_NO_FILESYSTEM;	/* No FAT volume is found */
    
    	/* An FAT volume is found. Following code initializes the file system object */
    
    	{
    	    /* 读取MBR中的BPB_BytsPerSec域,判断扇区大小是否是512(SS(fs)) */
    		if (ld_word(fs->win + BPB_BytsPerSec) != SS(fs)) return FR_NO_FILESYSTEM;	/* (BPB_BytsPerSec must be equal to the physical sector size) */
    
            /* 2.4获取FAT表的大小、FAT表的个数、每个簇的扇区数、根目录项数(对于FAT32不存在这个)、磁盘簇的个数、MBR、FAT表、数据区的位置、 */
    		fasize = ld_word(fs->win + BPB_FATSz16);			/* Number of sectors per FAT */
    		if (fasize == 0) fasize = ld_dword(fs->win + BPB_FATSz32);
    		fs->fsize = fasize;
    
    		fs->n_fats = fs->win[BPB_NumFATs];					/* Number of FATs */
    		if (fs->n_fats != 1 && fs->n_fats != 2) return FR_NO_FILESYSTEM;	/* (Must be 1 or 2) */
    		fasize *= fs->n_fats;								/* Number of sectors for FAT area */
    
    		fs->csize = fs->win[BPB_SecPerClus];				/* Cluster size */
    		if (fs->csize == 0 || (fs->csize & (fs->csize - 1))) return FR_NO_FILESYSTEM;	/* (Must be power of 2) */
    
    		fs->n_rootdir = ld_word(fs->win + BPB_RootEntCnt);	/* Number of root directory entries */
    		if (fs->n_rootdir % (SS(fs) / SZDIRE)) return FR_NO_FILESYSTEM;	/* (Must be sector aligned) */
    
    		tsect = ld_word(fs->win + BPB_TotSec16);			/* Number of sectors on the volume */
    		if (tsect == 0) tsect = ld_dword(fs->win + BPB_TotSec32);
    
    		nrsv = ld_word(fs->win + BPB_RsvdSecCnt);			/* Number of reserved sectors */
    		if (nrsv == 0) return FR_NO_FILESYSTEM;				/* (Must not be 0) */
    
    		/* Determine the FAT sub type */
    		sysect = nrsv + fasize + fs->n_rootdir / (SS(fs) / SZDIRE);	/* RSV + FAT + DIR */
    		if (tsect < sysect) return FR_NO_FILESYSTEM;		/* (Invalid volume size) */
    		nclst = (tsect - sysect) / fs->csize;				/* Number of clusters */
    		if (nclst == 0) return FR_NO_FILESYSTEM;			/* (Invalid volume size) */
    		fmt = FS_FAT32;
    		if (nclst <= MAX_FAT16) fmt = FS_FAT16;
    		if (nclst <= MAX_FAT12) fmt = FS_FAT12;
    
    		/* 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 (ld_word(fs->win + BPB_FSVer32) != 0) return FR_NO_FILESYSTEM;	/* (Must be FAT32 revision 0.0) */
    			if (fs->n_rootdir) return FR_NO_FILESYSTEM;		/* (BPB_RootEntCnt must be 0) */
    			fs->dirbase = ld_dword(fs->win + BPB_RootClus32);	/* Root directory start cluster */
    			szbfat = fs->n_fatent * 4;						/* (Needed FAT size) */
    		} else {
    			if (fs->n_rootdir == 0)	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)) return FR_NO_FILESYSTEM;	/* (BPB_FATSz must not be less than the size needed) */
    
    #if !_FS_READONLY
    		/* Get FSINFO if available */
    		fs->last_clst = fs->free_clst = 0xFFFFFFFF;		/* Initialize cluster allocation information */
    		fs->fsi_flag = 0x80;
    #if (_FS_NOFSINFO & 3) != 3
            /* 2.5判断是否存在FSINFO扇区,如果存在则读出可用簇数、下一个可用簇号到FATFS结构体中 */
    		if (fmt == FS_FAT32				/* Enable FSINFO only if FAT32 and BPB_FSInfo32 == 1 */
    			&& ld_word(fs->win + BPB_FSInfo32) == 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_clst = ld_dword(fs->win + FSI_Free_Count);
    #endif
    #if (_FS_NOFSINFO & 2) == 0
    				fs->last_clst = ld_dword(fs->win + FSI_Nxt_Free);
    #endif
    			}
    		}
    #endif	/* (_FS_NOFSINFO & 3) != 3 */
    #endif	/* !_FS_READONLY */
    	}
    
    	fs->fs_type = fmt;	/* FAT sub-type */
    	fs->id = ++Fsid;	/* File system mount ID */
    #if _USE_LFN == 1
    	fs->lfnbuf = LfnBuf;	/* Static LFN working buffer */
    #if _FS_EXFAT
    	fs->dirbuf = DirBuf;	/* Static directory block working buuffer */
    #endif
    #endif
    #if _FS_RPATH != 0
    	fs->cdir = 0;		/* Initialize current directory */
    #endif
    #if _FS_LOCK != 0		/* Clear file lock semaphores */
    	clear_lock(fs);
    #endif
    	return FR_OK;
    }
    

    总结

    f_mount函数就是读出MBR扇区的内容放入FATFS结构图中,供以后使用。

     

    展开全文
  • mount 函数

    千次阅读 2015-04-03 16:12:26
    当我们在Linux系统的板子上挂载U盘时,会出现,原本在windows上显示正常的文件名,在Linux下全部显示为问号?.... 如果需要显示出中文,需要使用uft8模式挂载U盘。... mount /dev/sdb4 /mnt/ho1 -o

    本文转自:http://blog.csdn.net/ypist/article/details/8181766

    当我们在Linux系统的板子上挂载U盘时,会出现,原本在windows上显示正常的文件名,在Linux下全部显示为问号?.

    如果需要显示出中文,需要使用uft8模式挂载U盘。

     

     解决中文字符显示问号的方法:
      mount /dev/sdb4 /mnt/ho1 -o iocharset=utf8

    然而,在程序中,使用mount函数来这样挂载,却出现了问题。

    首先,我们看看mount函数的定义:

    int  mount(const  char  *source,  const char *target, const char *filesystemtype, unsigned long mountflags, const void *data);
    source :设备 /dev/sda等;
    target :挂载点/mnt/usb等;
    *filesystemtype:"minix","ext2", "msdos", "proc", "nfs", "iso9660" ,“vfat”etc.;
    mountflags:MS_MGC_VAL/还有别的参数;
    *data:例如:”codepage=936,iocharset=cp936“。

     

    其中:

    mountflags 经查阅资料有如下选项:

    // MS_RELATIME  //(default for Linux >= 2.6.30) 
    // MS_STRICTATIME //(default for Linux < 2.6.30) 
    
    // http://harmattan-dev.nokia.com/docs/library/html/manpages/headers/sys/mount.html
    public enum MountFlags : ulong
    {
        MS_RDONLY = 1,         // Mount read-only.
        MS_NOSUID = 2,         // Ignore suid and sgid bits.
        MS_NODEV = 4,         // Disallow access to device special files.
        MS_NOEXEC = 8,         // Disallow program execution.
        MS_SYNCHRONOUS = 16,    // Writes are synced at once.
        MS_REMOUNT = 32,    // Alter flags of a mounted FS.
        MS_MANDLOCK = 64,    // Allow mandatory locks on an FS.
        S_WRITE = 128,   // Write on file/directory/symlink.
        S_APPEND = 256,   // Append-only file.
        S_IMMUTABLE = 512,   // Immutable file.
        MS_NOATIME = 1024,  // Do not update access times.
        MS_NODIRATIME = 2048,  // Do not update directory access times.
        MS_BIND = 4096,  // Bind directory at different place.
    }; // End Enum MountFlags : ulong


     

    iocharset=name
    Character set to use for converting from Unicode to ASCII. The default is to
    do no conversion. Use iocharset=utf8 for UTF8 translations. This requires
    CONFIG_NLS_UTF8 to be set in the kernel .config file.

    展开全文
  • f_mount函数

    千次阅读 2019-08-14 14:56:50
    f_mount The f_mount fucntion registers/unregisters filesystem object to the FatFs module. FRESULT f_mount ( FATFS* fs, /* [IN] Filesystem object */ const TCHAR* path, /* [IN] Logical d...

    f_mount

    The f_mount fucntion registers/unregisters filesystem object to the FatFs module.

    FRESULT f_mount (
      FATFS*       fs,    /* [IN] Filesystem object */
      const TCHAR* path,  /* [IN] Logical drive number */
      BYTE         opt    /* [IN] Initialization option */
    );

    Parameters

    fs
        Pointer to the filesystem object to be registered and cleared. Null pointer unregisters the registered filesystem object.
    path
        Pointer to the null-terminated string that specifies the logical drive. The string without drive number means the default drive.
    opt
        Mounting option. 0: Do not mount now (to be mounted on the first access to the volume), 1: Force mounted the volume to check if it is ready to work.

    Return Values

    FR_OK, FR_INVALID_DRIVE, FR_DISK_ERR, FR_NOT_READY, FR_NOT_ENABLED, FR_NO_FILESYSTEM
    Description

    FatFs needs work area (filesystem object) for each logical drives (FAT volumes). Prior to perform file/directory operations, a filesystem object needs to be registered with f_mount function to the logical drive. The file/directory API functions get ready to work after this procedure. If there is any open object of file or directory on the logical drive, the object will be invalidated by this function.

    The f_mount function registers/unregisters a filesystem object to the FatFs module as follows:

        Determines the logical drive which specified by path.
        Clears and unregisters the regsitered work area of the volume if exist.
        Clears and registers the new work area to the volume if fs is not NULL.
        Performs volume mount process to the volume if forced mounting is specified.

    If forced mounting is not specified (opt = 0), this function always succeeds regardless of the physical drive status. It only clears (de-initializes) the given work area and registers its address to the internal table and no activity of the physical drive in this function. To unregister the work area, specify a NULL to the fs, and then the work area can be discarded. The volume mount processes, initialize the corresponding physical drive, find the FAT volume in it and then initialize the work area, is performed in the subsequent file/directory functions when either of following conditions is true.

        Filesystem object has not been initialized. It is de-initialized by f_mount function.
        Physical drive is not initialized. It is de-initialized by system reset or media removal.

    If the function with forced mounting (opt = 1) failed, it means that the filesystem object has been registered successfully but the volume is currently not ready to work. The volume mount process will be attempted at subsequent file/directroy functions if the filesystem object is not initialized. (delayed mounting)

    If implementation of the disk I/O layer lacks asynchronous media change detection, application program needs to perform f_mount function after each media change to force cleared the filesystem object.
    QuickInfo

    Always available.
    Example

    int main (void)
    {
        FATFS *fs;     /* Ponter to the filesystem object */


        fs = malloc(sizeof (FATFS));           /* Get work area for the volume */
        f_mount(fs, "", 0);                    /* Mount the default drive */

        f_open(...                             /* Here any file API can be used */

        ...

        f_mount(fs, "", 0);                    /* Re-mount the default drive to reinitialize the filesystem */

        ...

        f_mount(0, "", 0);                     /* Unmount the default drive */
        free(fs);                              /* Here the work area can be discarded */

        ...
    }

       要特别的注意以下两个地方:
    1.  opt参数: Initialization option. 0: Do not mount now (to be mounted later), 1: Forcemounted the volume to check if the volume is available
         简单的说就是:如果设置opt参数为0,那么会在后面才执行加载操作,也就是说不管你是否外挂了设备,调用f_mount后,都会返回成功的。
         如果为1那么就会强制的进行加载操作。
    2.  使用这个函数还要注意返回值的含义,在程序调试时很有意义:
         FR_OK, FR_INVALID_DRIVE, FR_DISK_ERR, FR_NOT_READY, FR_NO_FILESYSTEM
    函数实例:
    和以前的版本不同,这里要注意调用方法:

    /* 挂载文件系统 */
    result = f_mount(&fs, "1:/", 0);    /* Mount a logical drive */
    /* 卸载文件系统 */
    result  = f_mount(NULL, "1:/", 0)

    通过下面这个函数可以更加方便的测试:

    static const char * FR_Table[]=
    {
        "FR_OK:成功",                                      /* (0) Succeeded */
        "FR_DISK_ERR:底层硬件错误",                      /* (1) A hard error occurred in the low level disk I/O layer */
        "FR_INT_ERR:断言失败",                              /* (2) Assertion failed */
        "FR_NOT_READY:物理驱动没有工作",                  /* (3) The physical drive cannot work */
        "FR_NO_FILE:文件不存在",                          /* (4) Could not find the file */
        "FR_NO_PATH:路径不存在",                          /* (5) Could not find the path */
        "FR_INVALID_NAME:无效文件名",                      /* (6) The path name format is invalid */
        "FR_DENIED:由于禁止访问或者目录已满访问被拒绝",  /* (7) Access denied due to prohibited access or directory full */
        "FR_EXIST:由于访问被禁止访问被拒绝",              /* (8) Access denied due to prohibited access */
        "FR_INVALID_OBJECT:文件或者目录对象无效",          /* (9) The file/directory object is invalid */
        "FR_WRITE_PROTECTED:物理驱动被写保护",              /* (10) The physical drive is write protected */
        "FR_INVALID_DRIVE:逻辑驱动号无效",                  /* (11) The logical drive number is invalid */
        "FR_NOT_ENABLED:卷中无工作区",                      /* (12) The volume has no work area */
        "FR_NO_FILESYSTEM:没有有效的FAT卷",              /* (13) There is no valid FAT volume */
        "FR_MKFS_ABORTED:由于参数错误f_mkfs()被终止",             /* (14) The f_mkfs() aborted due to any parameter error */
        "FR_TIMEOUT:在规定的时间内无法获得访问卷的许可",         /* (15) Could not get a grant to access the volume within defined period */
        "FR_LOCKED:由于文件共享策略操作被拒绝",                 /* (16) The operation is rejected according to the file sharing policy */
        "FR_NOT_ENOUGH_CORE:无法分配长文件名工作区",             /* (17) LFN working buffer could not be allocated */
        "FR_TOO_MANY_OPEN_FILES:当前打开的文件数大于_FS_SHARE", /* (18) Number of open files > _FS_SHARE */
        "FR_INVALID_PARAMETER:参数无效"                         /* (19) Given parameter is invalid */
    };

    测试函数**************************************************************************************************************************
    void Test_f_mount(void)
    {
        FRESULT result;
        FATFS fs;
        
        /* 挂载文件系统 */
      //  result = f_mount(&fs, "", 1);    /* Mount a logical drive */
        result = f_mount(&fs, "1:", 1);    /* Mount a logical drive */
        if (result != FR_OK)
        {
            printf("挂载文件系统失败 (%s)\r\n", FR_Table[result]);
        }
        else
        {
            printf("挂载文件系统成功 (%s)\r\n", FR_Table[result]);
        }
        
        /* 卸载文件系统 */
        result  = f_mount(NULL, "1:", 1);
        if (result != FR_OK)
        {
            printf("卸载文件系统失败 (%s)\r\n", FR_Table[result]);
        }
        else
        {
            printf("卸载文件系统成功 (%s)\r\n", FR_Table[result]);
        }
        
    }
    在fatfs外挂一个设备的时候,通过 f_mount(&fs, "", 1);就可以访问,而在多个设备时,就得指定磁盘号
         支持以下两种方式:
         f_mount(&fs, "1:", 1);
          f_mount(&fs, "1:/", 1);
          这种方式不支持:
         f_mount(&fs, "1", 1);
    ---------------------
    版权声明:本文为CSDN博主「lbaihao」的原创文章,遵循CC 4.0 by-sa版权协议,转载请附上原文出处链接及本声明。
    原文链接:https://blog.csdn.net/lbaihao/article/details/75144011

    展开全文
  • linux mount函数nfs挂载

    2020-06-10 18:53:24
    1、使用linux的mout函数挂载 #include <stdio.h> #include <sys/mount.h> #include <errno.h> #include <unistd.h> #include <sys/stat.h> #include <sys/types.h> #include &...

    1、使用linux的mout函数挂载

    #include <stdio.h>
    #include <sys/mount.h>
    #include <errno.h>
    #include <unistd.h>
    #include <sys/stat.h>
    #include <sys/types.h>
    #include <string.h>
    #include <sys/stat.h>
    #include <string.h>
    
    void test_mount()
    {
        /*
            char* src = ":/home/record/";
            char* opt = "addr=192.168.1.250,nolock,hard,bg,tcp,rsize=4096,vers=4,clientaddr=192.168.1.241";
        */
    
        char* src = "172.16.41.252:/home/record/";
        char* dst = "/mnt/cloud_nfs";
        /* 需要加上本地ip及远程主机ip,否则报错:Invalid argument */
        char* opt = "addr=172.16.41.252,nolock,hard,bg,tcp,rsize=4096,vers=4,clientaddr=172.16.41.208";
        int ret = mount(src, dst, "nfs", MS_SYNCHRONOUS, (void*)opt);
        if(ret < 0)
        {
            printf("mount error: %s\n", strerror(errno));
        }
    }
    
    int main()
    {
        test_mount();
        return 0;
    }
    

    执行程序之后,使用mount命令看不到挂载信息
    在这里插入图片描述
    需要使用cat /proc/mounts查看
    在这里插入图片描述

    展开全文
  • mount函数分析

    千次阅读 2016-07-06 22:13:53
    首先判断挂载的类型是否符和已经定义好的...mount_findfs(g_bdfsmap, filesystemtype); 其中g_bdfsmap就是已经定义好的文件系统类型。 static const struct fsmap_t g_bdfsmap[] = { #ifdef CONFIG_FS_FAT { "vfat
  • RT,应该是局部的对吧? 还是说情况特殊跟uid有关这样的?
  • ubifs mount 函数分析

    2015-05-18 16:19:39
    函数在super.c中的mount_ubifs()函数: ① 检测卷是否为空,如果volume为空的,而ubi为只读的就无法进行初始化。 ②  初始化:bottom_up_buf bottom_up_buf: a buffer which is used bydirty_cow_bottom_up...
  • mount 函数挂载的几点说明

    万次阅读 2012-11-14 10:48:36
    当我们在Linux系统的板子上挂载U盘时,会出现,原本在windows上显示正常的文件名,在Linux下全部显示为问号?. 如果需要显示出中文,...然而,在程序中,使用mount函数来这样挂载,却出现了问题。 首先,我们看看mo
  • 我这边碰到个mount函数挂载nfs 文件系统问题一直mount不成功,但是 用system可以,我需要关系mount返回值,请教各位同事是否有懂的,请大家指导小弟: int nErCode = mount(192.168.0.101:/tmp/nfs, /tmp/nfs, "nfs...
  • 在完整版中,vm.$mount会先检查template或el选项提供的模板是否已经转换成了渲染函数,如果没有则将模板编译成渲染函数。 而在只包含运行时的版本中,vm.$mount是没有编译模板的步骤的,它默认实例上已经有渲染函数了...
  • $mount函数执行位置 _init这个私有方法是在执行initMixin时候绑定到Vue原型上的。   $mount函数是如如何把组件挂在到指定元素 $mount函数定义位置 $mount函数定义位置有两个: 第一个是在src/platforms/web/...
  • Linux下mount/umount函数应用

    千次阅读 2017-10-18 16:35:23
    针对海思平台system命令占用资源较大的问题,因此程序中与系统调用相关的就只能用函数实现了。 demo mount.c: #include int main(void) { int ret = 0; ret = mount("/dev/mmcblk0p1","/mnt/sd_card","vfat",...
  • 挂载文件系统#include<sys/mount.h> int mount(const char *source,const char *target,const char *fstype,unsigned long mountflags,const void *data)其中mountflags的值可为: MS_BIND 建立绑定挂载,会忽略...
  • linux 文件操作函数 mount-mknod-mkdir

    千次阅读 2018-07-24 22:20:26
    1. mount/unmount 函数 功能描述 mount 挂载文件系统,unmount 则执行相反的操作 头文件 #include &amp;lt;sys/mount.h&amp;gt; #include &amp;lt;errno.h&amp;gt; // 用于 errno 的判断 ...
  • 功能描述:mount挂上文件系统,umount执行相反的操作。 头文件: #include <sys/mount.h> #include <errno.h> //errno的判断 用法: int mount(const char *source, const char *target, const char *...
  • linux开发---1.mount 函数

    千次阅读 2011-06-28 14:33:00
    linux开发---1.mount 函数
  • VFS之mount函数分析

    千次阅读 2011-10-15 23:10:54
    有此可见,vfs_kern_mount函数功能: 申请vfsmount结构,并调用到具体的相应文件系统的mount函数,相应的文件系统mount返回一个super_block的结构,vfs对其进行处理初步得到dentry结构, 最后用dentry结构对vfsmount...
  • 出现的意义:其实$mount()函数和Vue的el功能是一样的,将组件挂载到DOM元素之上,不同的是挂载的时机是不一样的。 el:是在Vue的实例创建过程中的create()钩子函数中进行初始化的 $mount():是手动挂起,挂载的时机...
  • 转载自:... 功能描述: mount挂上文件系统,umount执行相反的操作。 头文件: #include #include //errno的判断 用法:  int mount(const char *source, const c
  • mount/umount函数

    2016-03-25 17:30:09
    用法:  ...int mount(const char *source, const char *target,  const char *filesystemtype, unsigned long mountflags, const void *data); int umount(const char *target); int umount2(con
  • 关于mount、umount函数以及命令的区别

    千次阅读 2012-09-21 15:34:38
    在C函数中,加入mount或者umount去挂载卸载一个硬盘,加入硬盘不存在的话,函数会返回错误。而如果是用mount或者umnout命令去挂载或者卸载的话,可以正常调用。并且对于大容量的硬盘来说,用命令而非函数效率更高。...
  • Linux系统调用-- mount/umount函数详解

    万次阅读 2012-10-19 16:21:38
    mount/umount系统调用】    功能描述: mount挂上文件系统,umount执行相反的操作。   用法:  #include int mount(const char *source, const char *target,  const char *filesystemtype, ...
  • mount系统调用的原型如下 int mount(const char *source, const char *target, const char *filesystemtype, unsigned long mountflags, const void *data); 其中source为设备文件的路径名,target为挂载...
  • 挂载一个新的块设备时,内核会根据文件系统的类型,找到它的file_system_type对象,并调用该文件系统的mount函数mount函数初始化超级块对象,设置s_op函数指针,这样VFS通过这个指针就知道如何操作这个块设备了。...
  • mount: is busy 解决思路、方法

    千次阅读 2019-10-12 10:46:24
    mount: is busy 解决思路、方法,umount
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