本文介绍了df 和 statfs 的输出不同的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
限时送ChatGPT账号..为什么df命令的输出和statfs()系统调用值不同:
调用statfs的程序:
#include #include #include #include #include #include int main(){结构 statfs vfs;如果(statfs(/",& vfs)!= 0){fprintf(stderr, "%s: statfs 失败: %s\n","/", strerror(errno));退出(0);}printf("挂载在 %s:\n","/");printf("\tf_bsize: %ld\n", vfs.f_bsize);printf("\tf_blocks: %ld\n", vfs.f_blocks);printf("\tf_bfree: %ld\n", vfs.f_bfree);printf("\tf_bavail: %ld\n", vfs.f_bavail);printf("\tf_files: %ld\n", vfs.f_files);printf("\tf_ffree: %ld\n", vfs.f_ffree);返回0;}
输出:
<前>镶嵌在/:f_bsize: 4096f_blocks:119189762f_bfree:112718672f_bavail:106662506f_files:30285824f_ffree:29990111df 命令的输出:
<前>~$ df/文件系统 1K-blocks Used 可用使用% Mounted on/dev/sda1 476759048 25882620 426651764 6%/df 命令在内部调用 statfs 系统调用本身,但是为什么结构值和 df 命令的输出结果不同,谁能解释清楚.
解决方案df 的数据可能是基于 f_bavail
而不是 f_bfree
所以对于总空间和可用空间的计算可能如下
long long Total_Space = vfs.f_blocks;Total_Space *= vfs.f_frsize;Total_Space/= 1024;long long Avail_Space = vfs.f_bfree;Avail_Space *= vfs.f_frsize;Avail_Space/= 1024;printf("总空间=%lldKb 可用空间=%lldKB\n",Total_Space,Avail_Space);
why is the output of df command and statfs() system call values are different:
program to call statfs:
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/vfs.h>
#include <string.h>
#include <stdlib.h>
int main()
{
struct statfs vfs;
if (statfs("/", & vfs) != 0) {
fprintf(stderr, "%s: statfs failed: %s\n",
"/", strerror(errno));
exit(0);
}
printf("mounted on %s:\n","/");
printf("\tf_bsize: %ld\n", vfs.f_bsize);
printf("\tf_blocks: %ld\n", vfs.f_blocks);
printf("\tf_bfree: %ld\n", vfs.f_bfree);
printf("\tf_bavail: %ld\n", vfs.f_bavail);
printf("\tf_files: %ld\n", vfs.f_files);
printf("\tf_ffree: %ld\n", vfs.f_ffree);
return 0;
}
output:
mounted on /: f_bsize: 4096 f_blocks: 119189762 f_bfree: 112718672 f_bavail: 106662506 f_files: 30285824 f_ffree: 29990111
output of df command:
~$ df / Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 476759048 25882620 426651764 6% /
df command internally calls the statfs systemcall itself, but why is the output is different on structure values and the output of df command, can anyone explain me clearly.
解决方案df's data may be based on f_bavail
, not f_bfree
So for calculation of total space and available space may be as follows
long long Total_Space = vfs.f_blocks;
Total_Space *= vfs.f_frsize;
Total_Space /= 1024;
long long Avail_Space = vfs.f_bfree;
Avail_Space *= vfs.f_frsize;
Avail_Space /= 1024;
printf("Total Space=%lldKb Available Space=%lldKB\n",Total_Space,Avail_Space);
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