fuse：创建线程时出错：资源暂时不可用

Question

在为最简单的fuse文件系统编写getattr和readdir函数之后，我得到了fuse：创建线程的错误：资源暂时不可用..我想知道我的代码在哪里犯了错误

我已经搜索过这个，但找不到任何令我满意的东西。在我看来它超过了线程限制，但我不知道如何解决它。我编译了它

$ gcc passthrough.c -o passthrough `pkg-config fuse --cflags --libs`
passthrough.c:65:2: warning: initialization from incompatible pointer type [enabled by default]
  .getattr = e_getattr,
  ^
passthrough.c:65:2: warning: (near initialization for 'oper.getattr') [enabled by default]

这是程序的源代码

#define FUSE_USE_VERSION 26

#include <fuse.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <dirent.h>
#include <errno.h>
#include <sys/time.h>
#include <limits.h>

char rootdir[100];

void get_fullpath(char fpath[PATH_MAX], const char *path){
    strcpy(fpath,rootdir);
    strncat(fpath,path,PATH_MAX);
    printf("[fullpath] file: %s\n",fpath);
}

int e_getattr(const char *path, struct stat *stbuf, struct fuse_file_info *fi){
    (void)fi;
    int res;

    char fpath[PATH_MAX];
    get_fullpath(fpath,path);

    printf("[getattr] file: %s\n",fpath);

    res = lstat(fpath,stbuf);
    if (res == -1)
        return -errno;
    return 0;
}

int e_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset, struct fuse_file_info *fi){
    DIR *dp;
    struct dirent *de;

    (void)offset;
    (void)fi;

    char fpath[PATH_MAX];
    get_fullpath(fpath,path);
    printf("[readdir] file: %s\n",fpath);

    dp = opendir(fpath);
    if (dp == NULL)
        return -errno;

    while ((de = readdir(dp)) != NULL){
        struct stat st;
        memset(&st,0,sizeof(st));
        st.st_ino = de->d_ino;
        st.st_mode = de->d_type << 12;
        if (filler(buf,de->d_name,&st,0))
            break;
    }
    closedir(dp);
    return 0;
}

struct fuse_operations oper = {
    .getattr = e_getattr,
    .readdir = e_readdir,
};

int main(int argc, char * argv[]){
    umask(0);
    realpath(argv[2],rootdir);
    printf("Real path is %s\n",rootdir);
    return fuse_main(argc,argv,&oper,NULL);
}

这是我得到的输出

[fullpath] file: /home/echo/passthrough/test/
[getattr] file: /home/echo/passthrough/test/
[fullpath] file: /home/echo/passthrough/test/
[getattr] file: /home/echo/passthrough/test/
[fullpath] file: /home/echo/passthrough/test/
[getattr] file: /home/echo/passthrough/test/
[fullpath] file: /home/echo/passthrough/test/
[getattr] file: /home/echo/passthrough/test/
[fullpath] file: /home/echo/passthrough/test/
[getattr] file: /home/echo/passthrough/test/
[fullpath] file: /home/echo/passthrough/test/
[getattr] file: /home/echo/passthrough/test/
...
...
...
[fullpath] file: /home/echo/passthrough/test/
[getattr] file: /home/echo/passthrough/test/
fuse: error creating thread: Resource temporarily unavailable
[fullpath] file: /home/echo/passthrough/test/
[getattr] file: /home/echo/passthrough/test/

Answer 1

问题在于函数：e_getattr()它应该写成：

static int e_getattr(const char *path, struct stat *stbuf )
{
    int res;

    char fpath[PATH_MAX];
    get_fullpath(fpath,path);

    printf("[getattr] file: %s\n",fpath);

    res = lstat(fpath,stbuf);
    if (res == -1)
        return -ENONET;
    return 0;
}

注意添加的修饰符static

注意删除第三个函数参数

注意对-ENONET的返回（出错时）的修改

包含的头文件列表也缺少该语句;

#include <stdlib.h> // exposes function: `realpath()`

功能：e_getattr()还需要`static modifier