[英]Why does FUSE seem to be locking up all threads?
I took fuse hello.c and modified the bottom to show what I am talking about. 我拿了保险丝hello.c并修改了底部以显示我在说什么。 In my app I need to do things after my fuse FS is available.
在我的应用程序中,我需要在保险丝FS可用后做一些事情。 I also need another thread for IPC and keeping certain things up to date.
我还需要IPC的另一个线程,并保持某些事情是最新的。 Because
fuse_main
doesn't appear to return I threw it in its own thread. 因为
fuse_main
似乎没有返回,所以我把它扔在自己的线程中。
When I comment out fuse_main
the console shows A and B printed. 当我注释掉
fuse_main
,控制台显示A和B打印。 However if I don't comment out fuse_main
(which is in a different thread) only A is printed. 但是,如果我没有注释掉
fuse_main
(在不同的线程中),则仅打印A. How the heck is fuse stopping my main thread and how do I run code after FUSE does its thing? 如何保险丝停止我的主线程以及如何在FUSE执行其操作后运行代码?
#define FUSE_USE_VERSION 26
#include <fuse.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
static const char *hello_str = "Hello World!\n";
static const char *hello_path = "/hello";
static int hello_getattr(const char *path, struct stat *stbuf)
{
int res = 0;
memset(stbuf, 0, sizeof(struct stat));
if (strcmp(path, "/") == 0) {
stbuf->st_mode = S_IFDIR | 0755;
stbuf->st_nlink = 2;
} else if (strcmp(path, hello_path) == 0) {
stbuf->st_mode = S_IFREG | 0444;
stbuf->st_nlink = 1;
stbuf->st_size = strlen(hello_str);
} else
res = -ENOENT;
return res;
}
static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
off_t offset, struct fuse_file_info *fi)
{
(void) offset;
(void) fi;
if (strcmp(path, "/") != 0)
return -ENOENT;
filler(buf, ".", NULL, 0);
filler(buf, "..", NULL, 0);
filler(buf, hello_path + 1, NULL, 0);
return 0;
}
static int hello_open(const char *path, struct fuse_file_info *fi)
{
if (strcmp(path, hello_path) != 0)
return -ENOENT;
if ((fi->flags & 3) != O_RDONLY)
return -EACCES;
return 0;
}
static int hello_read(const char *path, char *buf, size_t size, off_t offset,
struct fuse_file_info *fi)
{
size_t len;
(void) fi;
if(strcmp(path, hello_path) != 0)
return -ENOENT;
len = strlen(hello_str);
if (offset < len) {
if (offset + size > len)
size = len - offset;
memcpy(buf, hello_str + offset, size);
} else
size = 0;
return size;
}
static struct fuse_operations hello_oper;
//modification starts below this line
#include<thread>
#include<unistd.h>
int main(int argc, char *argv[])
{
std::thread t([&]{
hello_oper.getattr = hello_getattr;
hello_oper.readdir = hello_readdir;
hello_oper.open = hello_open;
hello_oper.read = hello_read;
return fuse_main(argc, argv, &hello_oper, NULL);
});
printf("A\n");
sleep(5);
printf("B\n");
t.join();
}
fuse_main
daemonizes, ie calls fork()
and calls _exit(0)
in the parent process, so the process exits, hence you only see the A
printout. fuse_main
daemonizes,即调用fork()
并在父进程中调用_exit(0)
,因此进程退出,因此您只能看到A
打印输出。
If you give the option -f
in ./hello -f /tmp/fuse
the fuse_main
does not call _exit
but stays alive in the foreground and both A
and B
can be seen. 如果你给的选项
-f
在./hello -f /tmp/fuse
的fuse_main
不调用_exit
,但在前台和两个保持活着A
和B
就可以看出。
You surely need a way to end the fuse_main
thread gracefully when your program wants to exit: 当程序想要退出时,你肯定需要一种方法来优雅地结束
fuse_main
线程:
//modification starts below this line
#include<thread>
#include<unistd.h>
#include <signal.h>
#include <sys/syscall.h>
int main(int argc, char *argv[])
{
pid_t tid;
std::thread t([&]{
hello_oper.getattr = hello_getattr;
hello_oper.readdir = hello_readdir;
hello_oper.open = hello_open;
hello_oper.read = hello_read;
tid = syscall(SYS_gettid);
return fuse_main(argc, argv, &hello_oper, NULL);
});
printf("A\n");
sleep(5);
printf("B\n");
kill(tid, SIGTERM);
t.join();
}
Options for hello
: hello
选项:
general options:
-o opt,[opt...] mount options
-h --help print help
-V --version print version
FUSE options:
-d -o debug enable debug output (implies -f)
-f foreground operation
-s disable multi-threaded operation
[...]
From what I read in the documentation here http://fuse.sourceforge.net/doxygen/hello_8c.html on the usage of the hello.c
program, it says that the program exits and vanishes into the background, that is the nature of the fuse_main
API . 从我在http://fuse.sourceforge.net/doxygen/hello_8c.html文档中读到的
hello.c
程序的使用情况来看,它说程序退出并消失在后台,这就是本质fuse_main
API。 Why don't you give a try, starting with this code http://fuse.sourceforge.net/doxygen/hello__ll_8c.html , from their description, unlike hello.c this example will stay in the foreground. it also replaced the convenience function fuse_main(..) with a more low level approach.
为什么不试一试,从这个代码http://fuse.sourceforge.net/doxygen/hello__ll_8c.html开始 ,从他们的描述开始,
unlike hello.c this example will stay in the foreground. it also replaced the convenience function fuse_main(..) with a more low level approach.
unlike hello.c this example will stay in the foreground. it also replaced the convenience function fuse_main(..) with a more low level approach.
This way in the line, 这种方式在线,
err = fuse_session_loop(se);
in the main function you have control to have additions and do other things you wish to do. 在主要功能中,您可以控制添加内容并执行其他您想要执行的操作。
Also there is a c++ implementation for FUSE, https://code.google.com/p/fusekit/ 还有一个针对FUSE的c ++实现, https://code.google.com/p/fusekit/
Hope this helps. 希望这可以帮助。
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