diff options
| -rw-r--r-- | Documentation/vm/page-types.c | 105 |
1 files changed, 101 insertions, 4 deletions
diff --git a/Documentation/vm/page-types.c b/Documentation/vm/page-types.c index cc96ee2666f2..7445caa26d05 100644 --- a/Documentation/vm/page-types.c +++ b/Documentation/vm/page-types.c @@ -32,8 +32,20 @@ #include <sys/types.h> #include <sys/errno.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 */ @@ -152,6 +164,12 @@ static const char *page_flag_names[] = { }; +static const char *debugfs_known_mountpoints[] = { + "/sys/kernel/debug", + "/debug", + 0, +}; + /* * data structures */ @@ -184,7 +202,7 @@ static int kpageflags_fd; static int opt_hwpoison; 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_forget_fd; @@ -464,21 +482,100 @@ static uint64_t kpageflags_flags(uint64_t 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 */ static void prepare_hwpoison_fd(void) { - char buf[100]; + char buf[MAX_PATH + 1]; + + debugfs_mount(); 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); } 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); } } |