Documentation/vm/page-types.c: auto debugfs mount for hwpoison operation (12da58b0) · Commits · 戴 / test

Documentation/vm/page-types.c

+101 −4

Original line number	Original line	Diff line number	Diff line
	@@ -32,8 +32,20 @@
	#include <sys/types.h>		#include <sys/types.h>
	#include <sys/errno.h>		#include <sys/errno.h>
	#include <sys/fcntl.h>		#include <sys/fcntl.h>
			#include <sys/mount.h>
			#include <sys/statfs.h>
			#include "../../include/linux/magic.h"


			#ifndef MAX_PATH
			# define MAX_PATH 256
			#endif

			#ifndef STR
			# define _STR(x) #x
			# define STR(x) _STR(x)
			#endif

	/*		/*
	* pagemap kernel ABI bits		* pagemap kernel ABI bits
	*/		*/
	@@ -152,6 +164,12 @@ static const char *page_flag_names[] = {
	};		};


			static const char *debugfs_known_mountpoints[] = {
			"/sys/kernel/debug",
			"/debug",
			0,
			};

	/*		/*
	* data structures		* data structures
	*/		*/
	@@ -184,7 +202,7 @@ static int kpageflags_fd;
	static int opt_hwpoison;		static int opt_hwpoison;
	static int opt_unpoison;		static int opt_unpoison;

	static const char hwpoison_debug_fs[] = "/debug/hwpoison";		static char hwpoison_debug_fs[MAX_PATH+1];
	static int hwpoison_inject_fd;		static int hwpoison_inject_fd;
	static int hwpoison_forget_fd;		static int hwpoison_forget_fd;

	@@ -464,21 +482,100 @@ static uint64_t kpageflags_flags(uint64_t flags)
	return flags;		return flags;
	}		}

			/* verify that a mountpoint is actually a debugfs instance */
			static int debugfs_valid_mountpoint(const char *debugfs)
			{
			struct statfs st_fs;

			if (statfs(debugfs, &st_fs) < 0)
			return -ENOENT;
			else if (st_fs.f_type != (long) DEBUGFS_MAGIC)
			return -ENOENT;

			return 0;
			}

			/* find the path to the mounted debugfs */
			static const char *debugfs_find_mountpoint(void)
			{
			const char **ptr;
			char type[100];
			FILE *fp;

			ptr = debugfs_known_mountpoints;
			while (*ptr) {
			if (debugfs_valid_mountpoint(*ptr) == 0) {
			strcpy(hwpoison_debug_fs, *ptr);
			return hwpoison_debug_fs;
			}
			ptr++;
			}

			/* give up and parse /proc/mounts */
			fp = fopen("/proc/mounts", "r");
			if (fp == NULL)
			perror("Can't open /proc/mounts for read");

			while (fscanf(fp, "%*s %"
			STR(MAX_PATH)
			"s %99s %s %d %*d\n",
			hwpoison_debug_fs, type) == 2) {
			if (strcmp(type, "debugfs") == 0)
			break;
			}
			fclose(fp);

			if (strcmp(type, "debugfs") != 0)
			return NULL;

			return hwpoison_debug_fs;
			}

			/* mount the debugfs somewhere if it's not mounted */

			static void debugfs_mount(void)
			{
			const char **ptr;

			/* see if it's already mounted */
			if (debugfs_find_mountpoint())
			return;

			ptr = debugfs_known_mountpoints;
			while (*ptr) {
			if (mount(NULL, *ptr, "debugfs", 0, NULL) == 0) {
			/* save the mountpoint */
			strcpy(hwpoison_debug_fs, *ptr);
			break;
			}
			ptr++;
			}

			if (*ptr == NULL) {
			perror("mount debugfs");
			exit(EXIT_FAILURE);
			}
			}

	/*		/*
	* page actions		* page actions
	*/		*/

	static void prepare_hwpoison_fd(void)		static void prepare_hwpoison_fd(void)
	{		{
	char buf[100];		char buf[MAX_PATH + 1];

			debugfs_mount();

	if (opt_hwpoison && !hwpoison_inject_fd) {		if (opt_hwpoison && !hwpoison_inject_fd) {
	sprintf(buf, "%s/corrupt-pfn", hwpoison_debug_fs);		snprintf(buf, MAX_PATH, "%s/hwpoison/corrupt-pfn",
			hwpoison_debug_fs);
	hwpoison_inject_fd = checked_open(buf, O_WRONLY);		hwpoison_inject_fd = checked_open(buf, O_WRONLY);
	}		}

	if (opt_unpoison && !hwpoison_forget_fd) {		if (opt_unpoison && !hwpoison_forget_fd) {
	sprintf(buf, "%s/unpoison-pfn", hwpoison_debug_fs);		snprintf(buf, MAX_PATH, "%s/hwpoison/unpoison-pfn",
			hwpoison_debug_fs);
	hwpoison_forget_fd = checked_open(buf, O_WRONLY);		hwpoison_forget_fd = checked_open(buf, O_WRONLY);
	}		}
	}		}

Admin message