SEM到底是什么？包括哪些方面？

SEO主要是为了关键词的排名、网站的流量、网站的结构、搜索引擎中页面收录的数据。

]SEM是通过SEO技术基础上扩展为搜索引擎中所带来的商业价值，策划有效的网络营销方案，包括一系列的网站运营策略分析，并进行实施，营销效果进行检测。

搜索引擎营销(SEM)服务主要方式

从营销的角度出发，为客户制定及实施符合其需求的SEM策略方案，从而提高网站的高效流量与转化率，获得更多的潜在客户关注。

1、竞价排名，顾名思义就是网站付费后才能被搜索引擎收录，付费越高者排名越靠前竞价排名服务，是由客户为自己的网页购买关键字排名，按点击计费的一种服务。客户可以通过调整每次点击付费价格，控制自己在特定关键字搜索结果中的排名，并可以通过设定不同的关键词捕捉到不同类型的的目标访问者。

而在国内最流行的点击付费搜索引擎有百度，雅虎和Google。值得一提的是即使是做了PPC (Pay Per Click，按照点击收费)付费广告和竞价排名，最好也应该对网站进行搜索引擎优化设计，并将网站登录到各大免费的搜索引擎中。

2、购买关键词广告，即在搜索结果页面显示广告内容，实现高级定位投放，用户可以根据需要更换关键词，相当于在不同页面轮换投放广告。

3、搜索引擎优化(SEO)，就是通过对网站优化设计，使得网站在搜索结果中靠前。搜索引擎优化(SEO)又包括网站内容优化、关键词优化、外部链接优化、内部链接优化、代码优化、图片优化、搜索引擎登录等。

4、PPC( Pay Per call，按照有效通话收费 )，比如：“TMTW来电付费”，就是根据有效电话的数量进行收费，购买竞价广告也被称做PPC。

目前，SEM正处于发展阶段，它将成为今后专业网站乃至电子商务发展的必经之路。 搜索引擎营销(SEM)流程

概述====1)当内核配置了内存盘时, 内核在初始化时可以将软盘加载到内存盘中作为根盘.当同时配置了初始化内存盘(Initail RAM Disk)时, 内核在初始化时可以在安装主盘之前,通过引导程序所加载的initrd文件建立一个内存初始化盘, 首先将它安装成根文件系统, 然后执行其根目录下的linuxrc 文件,可用于在安装主盘之前加载一些内核模块. 等到linuxrc 程序退出后, 再将主盘安装成根文件系统,并将内存初始化盘转移安装到其/initrd目录下.2)当主盘就是initrd所生成的内存初始化盘时, 不再进行重新安装,在DOS下用loadlin加载的抢救盘就是这种工作方式.3)引导程序所加载的initrd为文件系统的映象文件, 可以是gzip压缩的, 也可以是不压缩的.能够识别的文件系统有minix,ext2,romfs三种.4)当内核的根盘为软盘时,内核初始化时会测试软盘的指定部位是否存在文件系统或压缩文件映象, 然后将之加载或解压到内存盘中作为根盘. 这是单张抢救软盘的工作方式.有关代码========init/main.c#ifdef CONFIG_BLK_DEV_INITRDkdev_t real_root_dev启动参数所设定的根盘设备#endifasmlinkage void __init start_kernel(void){ char * command_lineunsigned long mempagesextern char saved_command_line[]lock_kernel()printk(linux_banner)setup_arch(&command_line)arch/i386/kernel/setup.c中,初始化initrd_start和initrd_end两个变量 ...#ifdef CONFIG_BLK_DEV_INITRD if (initrd_start &&!initrd_below_start_ok && initrd_start <min_low_pfn <<PAGE_SHIFT) { min_low_pfn为内核末端_end所开始的物理页号,initrd_start,initrd_end在rd.c中定义 printk(KERN_CRIT "initrd overwritten (0x%08lx <0x%08lx) - " "disabling it./n",initrd_start,min_low_pfn <<PAGE_SHIFT) initrd_start = 0}#endif ... kernel_thread(init, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGNAL)创建init进程 unlock_kernel()current->need_resched = 1 cpu_idle()}static int init(void * unused){ lock_kernel()do_basic_setup() /* * Ok, we have completed the initial bootup, and * we're essentially up and running. Get rid of the * initmem segments and start the user-mode stuff.. */ free_initmem()unlock_kernel()if (open("/dev/console", O_RDWR, 0) <0) printk("Warning: unable to open an initial console./n")(void) dup(0)(void) dup(0)/* * We try each of these until one succeeds. * * The Bourne shell can be used instead of init if we are * trying to recover a really broken machine. */ if (execute_command) execve(execute_command,argv_init,envp_init)execve("/sbin/init",argv_init,envp_init)execve("/etc/init",argv_init,envp_init)execve("/bin/init",argv_init,envp_init)execve("/bin/sh",argv_init,envp_init)panic("No init found. Try passing init= option to kernel.")}static void __init do_basic_setup(void){#ifdef CONFIG_BLK_DEV_INITRD int real_root_mountflags#endif ...#ifdef CONFIG_BLK_DEV_INITRD real_root_dev = ROOT_DEVROOT_DEV为所请求根文件系统的块设备 real_root_mountflags = root_mountflagsif (initrd_start &&mount_initrd) root_mountflags &= ~MS_RDONLYelse mount_initrd =0#endif start_context_thread()do_initcalls()会调用partition_setup()中加载内存盘 /* .. filesystems .. */ filesystem_setup()/* Mount the root filesystem.. */ mount_root()mount_devfs_fs ()#ifdef CONFIG_BLK_DEV_INITRD root_mountflags = real_root_mountflagsif (mount_initrd &&ROOT_DEV != real_root_dev &&MAJOR(ROOT_DEV) == RAMDISK_MAJOR &&MINOR(ROOT_DEV) == 0) { 如果当前根盘为initrd所建立的内存盘 int error int i, pid pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD)创建新的任务去执行程序/linuxrc if (pid>0) while (pid != wait(&i))等待linuxrc进程退出 if (MAJOR(real_root_dev) != RAMDISK_MAJOR || MINOR(real_root_dev) != 0) { 如果原来的根盘不是0号内存盘,则使用原来的根文件系统, 并且将内存盘转移到其/initrd目录下 error = change_root(real_root_dev,"/initrd") if (error)printk(KERN_ERR "Change root to /initrd: ""error %d/n",error) } }#endif}#ifdef CONFIG_BLK_DEV_INITRDstatic int do_linuxrc(void * shell){ static char *argv[] = { "linuxrc", NULL, }close(0)close(1)close(2)setsid()设置新的session号 (void) open("/dev/console",O_RDWR,0)(void) dup(0)(void) dup(0)return execve(shell, argv, envp_init)}#endifarch/i386/kernel/setup.c#define RAMDISK_IMAGE_START_MASK 0x07FF#define RAMDISK_PROMPT_FLAG 0x8000#define RAMDISK_LOAD_FLAG 0x4000 #define PARAM ((unsigned char *)empty_zero_page)#define RAMDISK_FLAGS (*(unsigned short *) (PARAM+0x1F8)) 可用rdev设置的参数#define LOADER_TYPE (*(unsigned char *) (PARAM+0x210))#define INITRD_START (*(unsigned long *) (PARAM+0x218)) 初始化盘映象起始物理地址#define INITRD_SIZE (*(unsigned long *) (PARAM+0x21c)) 初始化盘字节数void __init setup_arch(char **cmdline_p){ ...#ifdef CONFIG_BLK_DEV_RAM rd_image_start = RAMDISK_FLAGS &RAMDISK_IMAGE_START_MASK以块为单位 rd_prompt = ((RAMDISK_FLAGS &RAMDISK_PROMPT_FLAG) != 0)rd_doload = ((RAMDISK_FLAGS &RAMDISK_LOAD_FLAG) != 0)#endif ...#ifdef CONFIG_BLK_DEV_INITRD if (LOADER_TYPE &&INITRD_START) { if (INITRD_START + INITRD_SIZE <= (max_low_pfn <<PAGE_SHIFT)) { max_low_pfn表示内核空间1G范围以下最大允许的物理页号 reserve_bootmem(INITRD_START, INITRD_SIZE) initrd_start =INITRD_START ? INITRD_START + PAGE_OFFSET : 0转变为内核逻辑地址 initrd_end = initrd_start+INITRD_SIZE } else { printk("initrd extends beyond end of memory " "(0x%08lx >0x%08lx)/ndisabling initrd/n", INITRD_START + INITRD_SIZE, max_low_pfn <<PAGE_SHIFT) initrd_start = 0 } }#endif ...}fs/partitions/check.c:int __init partition_setup(void){ device_init()包含ramdisk设备的初始化#ifdef CONFIG_BLK_DEV_RAM#ifdef CONFIG_BLK_DEV_INITRD if (initrd_start &&mount_initrd) initrd_load() 如果启动时加载了initrd文件,则用它去初始化根内存盘 else#endif rd_load()如果内核配置了内存盘并且根盘指定为软盘则试图将软盘加载为根内存盘#endif return 0}__initcall(partition_setup)drivers/block/rd.c:int rd_doload /* 1 = load RAM disk, 0 = don't load */int rd_prompt = 1 /* 1 = prompt for RAM disk, 0 = don't prompt */int rd_image_start /* starting block # of image */#ifdef CONFIG_BLK_DEV_INITRDunsigned long initrd_start, initrd_endint mount_initrd = 1 /* zero if initrd should not be mounted */int initrd_below_start_okvoid __init rd_load(void){ rd_load_disk(0)加载到0号内存盘}void __init rd_load_secondary(void){ rd_load_disk(1)加载到1号内存盘}static void __init rd_load_disk(int n){#ifdef CONFIG_BLK_DEV_INITRD extern kdev_t real_root_dev#endif if (rd_doload == 0) returnif (MAJOR(ROOT_DEV) != FLOPPY_MAJOR 如果根盘是不软盘#ifdef CONFIG_BLK_DEV_INITRD &&MAJOR(real_root_dev) != FLOPPY_MAJOR#endif ) return if (rd_prompt) {#ifdef CONFIG_BLK_DEV_FD floppy_eject()#endif#ifdef CONFIG_MAC_FLOPPY if(MAJOR(ROOT_DEV) == FLOPPY_MAJOR) swim3_fd_eject(MINOR(ROOT_DEV)) else if(MAJOR(real_root_dev) == FLOPPY_MAJOR) swim3_fd_eject(MINOR(real_root_dev))#endif printk(KERN_NOTICE "VFS: Insert root floppy disk to be loaded into RAM disk and press ENTER/n") wait_for_keypress()} rd_load_image(ROOT_DEV,rd_image_start, n)将根软盘加载到n号内存盘}void __init initrd_load(void){ 使用initrd设备盘作为源盘去建立内存根盘 rd_load_image(MKDEV(MAJOR_NR, INITRD_MINOR),rd_image_start,0)}static void __init rd_load_image(kdev_t device, int offset, int unit){ struct inode *inode, *out_inodestruct file infile, outfilestruct dentry in_dentry, out_dentrymm_segment_t fskdev_t ram_deviceint nblocks, ichar *bufunsigned short rotate = 0unsigned short devblocks = 0char rotator[4] = { '|' , '/' , '-' , '//' }ram_device = MKDEV(MAJOR_NR, unit)建立输出内存盘设备号 if ((inode = get_empty_inode()) == NULL) returnmemset(&infile, 0, sizeof(infile))memset(&in_dentry, 0, sizeof(in_dentry))infile.f_mode = 1/* read only */ infile.f_dentry = &in_dentryin_dentry.d_inode = inodeinfile.f_op = &def_blk_fopsinit_special_inode(inode, S_IFBLK | S_IRUSR, kdev_t_to_nr(device)) if ((out_inode = get_empty_inode()) == NULL) goto free_inodememset(&outfile, 0, sizeof(outfile))memset(&out_dentry, 0, sizeof(out_dentry))outfile.f_mode = 3/* read/write */ outfile.f_dentry = &out_dentryout_dentry.d_inode = out_inodeoutfile.f_op = &def_blk_fopsinit_special_inode(out_inode, S_IFBLK | S_IRUSR | S_IWUSR, kdev_t_to_nr(ram_device))if (blkdev_open(inode, &infile) != 0) 打开输入盘文件 goto free_inodeif (blkdev_open(out_inode, &outfile) != 0) 打开输出内存盘文件 goto free_inodesfs = get_fs()set_fs(KERNEL_DS)nblocks = identify_ramdisk_image(device, &infile, offset)鉴定输入盘的文件类型 if (nblocks <0) 出错 goto doneif (nblocks == 0) { 表示输入盘是gzip文件#ifdef BUILD_CRAMDISK if (crd_load(&infile, &outfile) == 0) 将输入盘文件解压到输出盘文件中去 goto successful_load#else printk(KERN_NOTICE "RAMDISK: Kernel does not support compressed " "RAM disk images/n")#endif goto done} /* * NOTE NOTE: nblocks suppose that the blocksize is BLOCK_SIZE, so * rd_load_image will work only with filesystem BLOCK_SIZE wide! * So make sure to use 1k blocksize while generating ext2fs * ramdisk-images. */ if (nblocks >(rd_length[unit] >>BLOCK_SIZE_BITS)) { 如果输入盘的尺寸超过了输出内存盘的允许尺寸 printk("RAMDISK: image too big! (%d/%ld blocks)/n", nblocks, rd_length[unit] >>BLOCK_SIZE_BITS) goto done} /* * OK, time to copy in the data */ buf = kmalloc(BLOCK_SIZE, GFP_KERNEL)if (buf == 0) { printk(KERN_ERR "RAMDISK: could not allocate buffer/n") goto done} if (blk_size[MAJOR(device)]) devblocks = blk_size[MAJOR(device)][MINOR(device)]取输入盘的容量#ifdef CONFIG_BLK_DEV_INITRD if (MAJOR(device) == MAJOR_NR &&MINOR(device) == INITRD_MINOR) devblocks = nblocks如果输入是初始化内存盘,则盘的容量为它的实际尺寸#endif if (devblocks == 0) { printk(KERN_ERR "RAMDISK: could not determine device size/n") goto done} printk(KERN_NOTICE "RAMDISK: Loading %d blocks [%d disk%s] into ram disk... ", nblocks, ((nblocks-1)/devblocks)+1, nblocks>devblocks ? "s" : "")for (i=0i <nblocksi++) { if (i &&(i % devblocks == 0)) { printk("done disk #%d./n", i/devblocks) rotate = 0 invalidate_buffers(device)使输入盘设备缓冲区无效 if (infile.f_op->release)infile.f_op->release(inode, &infile) printk("Please insert disk #%d and press ENTER/n", i/devblocks+1) wait_for_keypress() if (blkdev_open(inode, &infile) != 0) {printk("Error opening disk./n") goto done } infile.f_pos = 0 printk("Loading disk #%d... ", i/devblocks+1) } infile.f_op->read(&infile, buf, BLOCK_SIZE, &infile.f_pos) outfile.f_op->write(&outfile, buf, BLOCK_SIZE, &outfile.f_pos)#if !defined(CONFIG_ARCH_S390) if (!(i % 16)) { printk("%c/b", rotator[rotate &0x3]) rotate++ }#endif } printk("done./n")kfree(buf)successful_load: invalidate_buffers(device)ROOT_DEV = MKDEV(MAJOR_NR, unit)将根盘设备设置为当前加载的内存盘 if (ROOT_DEVICE_NAME != NULL) strcpy (ROOT_DEVICE_NAME, "rd/0")done: if (infile.f_op->release) infile.f_op->release(inode, &infile)set_fs(fs)returnfree_inodes: /* free inodes on error */ iput(out_inode)blkdev_put(inode->i_bdev, BDEV_FILE)free_inode: iput(inode)}int __init identify_ramdisk_image(kdev_t device, struct file *fp, int start_block){ const int size = 512struct minix_super_block *minixsbstruct ext2_super_block *ext2sbstruct romfs_super_block *romfsbint nblocks = -1unsigned char *bufbuf = kmalloc(size, GFP_KERNEL)if (buf == 0) return -1minixsb = (struct minix_super_block *) bufext2sb = (struct ext2_super_block *) bufromfsb = (struct romfs_super_block *) bufmemset(buf, 0xe5, size)/* * Read block 0 to test for gzipped kernel */ if (fp->f_op->llseek) fp->f_op->llseek(fp, start_block * BLOCK_SIZE, 0)fp->f_pos = start_block * BLOCK_SIZEfp->f_op->read(fp, buf, size, &fp->f_pos)读取offset开始的512字节 /* * If it matches the gzip magic numbers, return -1 */ if (buf[0] == 037 &&((buf[1] == 0213) || (buf[1] == 0236))) { printk(KERN_NOTICE "RAMDISK: Compressed image found at block %d/n", start_block) nblocks = 0 goto done} /* romfs is at block zero too */ if (romfsb->word0 == ROMSB_WORD0 &&romfsb->word1 == ROMSB_WORD1) { printk(KERN_NOTICE "RAMDISK: romfs filesystem found at block %d/n", start_block) nblocks = (ntohl(romfsb->size)+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS goto done} /* * Read block 1 to test for minix and ext2 superblock */ if (fp->f_op->llseek) fp->f_op->llseek(fp, (start_block+1) * BLOCK_SIZE, 0)fp->f_pos = (start_block+1) * BLOCK_SIZEfp->f_op->read(fp, buf, size, &fp->f_pos)/* Try minix */ if (minixsb->s_magic == MINIX_SUPER_MAGIC || minixsb->s_magic == MINIX_SUPER_MAGIC2) { printk(KERN_NOTICE "RAMDISK: Minix filesystem found at block %d/n", start_block) nblocks = minixsb->s_nzones <<minixsb->s_log_zone_size goto done} /* Try ext2 */ if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) { printk(KERN_NOTICE "RAMDISK: ext2 filesystem found at block %d/n", start_block) nblocks = le32_to_cpu(ext2sb->s_blocks_count) goto done} printk(KERN_NOTICE"RAMDISK: Couldn't find valid RAM disk image starting at %d./n",start_block)done: if (fp->f_op->llseek) fp->f_op->llseek(fp, start_block * BLOCK_SIZE, 0)fp->f_pos = start_block * BLOCK_SIZE kfree(buf)return nblocks}fs/super.cvoid __init mount_root(void){ struct file_system_type * fs_typestruct super_block * sbstruct vfsmount *vfsmntstruct block_device *bdev = NULLmode_t modeint retvalvoid *handlechar path[64]int path_start = -1#ifdef CONFIG_BLK_DEV_FD if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) { 当根盘还是软盘,表示没有加载过内存盘#ifdef CONFIG_BLK_DEV_RAM extern int rd_doload extern void rd_load_secondary(void)#endif floppy_eject()#ifndef CONFIG_BLK_DEV_RAM printk(KERN_NOTICE "(Warning, this kernel has no ramdisk support)/n")#else /* rd_doload is 2 for a dual initrd/ramload setup */ 只有当加载了initrd但没有释放到内存盘中(mount_inird=0)才有可能到这一步 if(rd_doload==2) rd_load_secondary()加载另一张软盘到1号内存盘作为根盘 else#endif { printk(KERN_NOTICE "VFS: Insert root floppy and press ENTER/n") wait_for_keypress() } }#endif devfs_make_root (root_device_name)handle = devfs_find_handle (NULL, ROOT_DEVICE_NAME, MAJOR (ROOT_DEV), MINOR (ROOT_DEV),DEVFS_SPECIAL_BLK, 1)if (handle) /* Sigh: bd*() functions only paper over the cracks */ { unsigned major, minordevfs_get_maj_min (handle, &major, &minor)ROOT_DEV = MKDEV (major, minor)} /* * Probably pure paranoia, but I'm less than happy about delving into * devfs crap and checking it right now. Later. */ if (!ROOT_DEV) panic("I have no root and I want to scream")bdev = bdget(kdev_t_to_nr(ROOT_DEV))if (!bdev) panic(__FUNCTION__ ": unable to allocate root device")bdev->bd_op = devfs_get_ops (handle)path_start = devfs_generate_path (handle, path + 5, sizeof (path) - 5)mode = FMODE_READif (!(root_mountflags &MS_RDONLY)) mode |= FMODE_WRITEretval = blkdev_get(bdev, mode, 0, BDEV_FS)if (retval == -EROFS) { root_mountflags |= MS_RDONLY retval = blkdev_get(bdev, FMODE_READ, 0, BDEV_FS)} if (retval) { /* * Allow the user to distinguish between failed open * and bad superblock on root device. */ printk ("VFS: Cannot open root device /"%s/" or %s/n", root_device_name, kdevname (ROOT_DEV)) printk ("Please append a correct /"root=/" boot option/n") panic("VFS: Unable to mount root fs on %s", kdevname(ROOT_DEV))} check_disk_change(ROOT_DEV)sb = get_super(ROOT_DEV)取根盘的超级块 if (sb) { fs_type = sb->s_type goto mount_it} read_lock(&file_systems_lock)for (fs_type = file_systems fs_type fs_type = fs_type->next) {if (!(fs_type->fs_flags &FS_REQUIRES_DEV)) continue根文件系统必须依赖于块设备 if (!try_inc_mod_count(fs_type->owner)) continue当文件系统模块正在删除过程中 read_unlock(&file_systems_lock) sb = read_super(ROOT_DEV,bdev,fs_type,root_mountflags,NULL,1)建立根盘的超级块结构 if (sb)goto mount_it read_lock(&file_systems_lock) put_filesystem(fs_type)释放对文件系统模块的引用 } read_unlock(&file_systems_lock)panic("VFS: Unable to mount root fs on %s", kdevname(ROOT_DEV))mount_it: printk ("VFS: Mounted root (%s filesystem)%s./n", fs_type->name, (sb->s_flags &MS_RDONLY) ? " readonly" : "")if (path_start >= 0) { devfs_mk_symlink (NULL, "root", DEVFS_FL_DEFAULT, path + 5 + path_start, NULL, NULL) memcpy (path + path_start, "/dev/", 5) vfsmnt = add_vfsmnt(NULL, sb->s_root, path + path_start) } else vfsmnt = add_vfsmnt(NULL, sb->s_root, "/dev/root")建立根盘的安装结构 /* FIXME: if something will try to umount us right now... */ if (vfsmnt) { set_fs_root(current->fs, vfsmnt, sb->s_root)设置当前进程的根盘和根目录 set_fs_pwd(current->fs, vfsmnt, sb->s_root) 设置当前进程的当前盘和当前目录 if (bdev) bdput(bdev)/* sb holds a reference */ return} panic("VFS: add_vfsmnt failed for root fs")}#ifdef CONFIG_BLK_DEV_INITRDint __init change_root(kdev_t new_root_dev,const char *put_old){ 以new_root_dev作为根盘重新安装根文件系统,原来的根转移到put_old目录下 struct vfsmount *old_rootmntstruct nameidata devfs_nd, ndint error = 0read_lock(¤t->fs->lock)old_rootmnt = mntget(current->fs->rootmnt)取当前进程的根盘安装结构 read_unlock(¤t->fs->lock)/* First unmount devfs if mounted */ if (path_init("/dev", LOOKUP_FOLLOW|LOOKUP_POSITIVE, &devfs_nd)) error = path_walk("/dev", &devfs_nd)if (!error) { if (devfs_nd.mnt->mnt_sb->s_magic == DEVFS_SUPER_MAGIC && devfs_nd.dentry == devfs_nd.mnt->mnt_root) { dput(devfs_nd.dentry) down(&mount_sem) /* puts devfs_nd.mnt */ do_umount(devfs_nd.mnt, 0, 0) up(&mount_sem) } elsepath_release(&devfs_nd)} ROOT_DEV = new_root_devmount_root()改变根盘设备重新安装根文件系统#if 1 shrink_dcache()清除目录项缓冲中所有自由的目录项 printk("change_root: old root has d_count=%d/n", atomic_read(&old_rootmnt->mnt_root->d_count))#endif mount_devfs_fs ()/* * Get the new mount directory */ error = 0if (path_init(put_old, LOOKUP_FOLLOW|LOOKUP_POSITIVE|LOOKUP_DIRECTORY, &nd)) error = path_walk(put_old, &nd)在新的根盘中寻找put_old目录 if (error) { int blivet printk(KERN_NOTICE "Trying to unmount old root ... ") blivet = do_umount(old_rootmnt, 1, 0)卸载原始的根盘 if (!blivet) { printk("okay/n") return 0 } printk(KERN_ERR "error %d/n", blivet) return error} /* FIXME: we should hold i_zombie on nd.dentry */ move_vfsmnt(old_rootmnt, nd.dentry, nd.mnt, "/dev/root.old")mntput(old_rootmnt)path_release(&nd)return 0}#endifstatic struct vfsmount *add_vfsmnt(struct nameidata *nd, 在虚拟文件系统中的安装点struct dentry *root, 安装盘的根目录项const char *dev_name) 安装盘名称{ struct vfsmount *mnt

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原文链接：https://blog.csdn.net/huanghaibin/java/article/details/478215

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