如何知道分区情况？
我使用的是 Linux（Ubuntu 11.10）。 好吧，当我调用系统调用 open 时，例如在 C 程序中：
size_t filedesc = open("testfile.txt",O_CREAT | O_WRONLY,0640);
如何访问分区，我的意思是有没有办法返回所使用的分区？
系统调用 open 的定义如上：
SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, int, mode)
如果我愿意，我可以输入 printk("%s",filename) 并查看路径。但是我如何访问该分区呢？
示例：我在两个不同的分区中有两个存档 example.txt（例如 /dev/sda1 和 /dev/sda2）。
然后我调用系统调用 open： 假设我调用了分区 /dev/sda2 中的 example.txt。 有没有办法使用 open 系统调用来访问分区（例如，printk(KERN_ALERT "%s",partition)）？
I'm using Linux (Ubuntu 11.10).
Well, when I call the system call open, for example in a C program:
size_t filedesc = open("testfile.txt",O_CREAT | O_WRONLY,0640);
How can I access the partition, I mean is there a way to return the partition used?
The system call open is the defined above:
SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, int, mode)
If I want, I can put a printk("%s",filename) and see the path. But how I can access the partition?
An example: I have two archives example.txt in two different partitions (for example /dev/sda1 and /dev/sda2).
Then I call the system call open: Lets suppose I called the example.txt in the partition /dev/sda2.
Is there a way to acess the partition (for example, printk(KERN_ALERT "%s",partition)) using the open system call?
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没有什么像您希望的那么简单。
在
do_sys_open()函数中，在return fd;之前，struct file *f指向一个合法的、打开的struct文件。结构文件包含一个结构路径f_path。struct path包含一个struct vfsmount *mnt。struct vfsmount代表系统上每个已挂载的文件系统。struct vfsmount包含一个struct super_block *mnt_sb。struct super_block包含一个struct block_device *s_bdev。struct block_device包含一个struct hd_struct *bd_part。struct hd_struct包含一个struct device __dev和一个int partno。这两者共同定义了您的文件所在的分区。更新
当我找到设备和分区号引用时，我最初停止了查找，因为我认为这就是将人类友好的字符串组合在一起所需的全部内容。但当我再次用新的眼光观察时，我发现还有更多内容：
struct hd_struct 包含一个 structpartition_meta_info *info。
struct partition_meta_info包含一个字段：该字段是您要查找的设备的名称。
There's nothing as simple as you might hope.
Within the
do_sys_open()function, immediately beforereturn fd;, thestruct file *fpoints to a legitimate, opened,struct file.The
struct filecontains astruct path f_path.The
struct pathcontains astruct vfsmount *mnt.struct vfsmountrepresents every mounted filesystem on the system.The
struct vfsmountcontains astruct super_block *mnt_sb.The
struct super_blockcontains astruct block_device *s_bdev.The
struct block_devicecontains astruct hd_struct *bd_part.The
struct hd_structcontains astruct device __devand anint partno. Together, these two define which partition your file is located on.Update
I had originally stopped looking when I found the device and partition number references, since I assumed that was all that was required to put together the human-friendly string. But when looking again with fresh eyes, I see there is more:
The
struct hd_structcontains astruct partition_meta_info *info.The
struct partition_meta_infocontains a field:This field is name of the device you're after.
通过 shell，
df /some/dir为您提供所涉及的文件系统。以编程方式，使用stat系统调用，您将获得st_dev字段。（补充：）我不知道你到底想做什么，但也许使用 来做到这一点FUSE 可以更简单。
Thru a shell,
df /some/dirgives you the file-system involved. Programmatically, withstatsystem call, you get thest_devfield.(added:) I don't guess what you want to do exactly, but perhaps doing that using FUSE could be simpler.