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-rw-r--r--mdmon.c594
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diff --git a/mdmon.c b/mdmon.c
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+/*
+ * mdmon - monitor external metadata arrays
+ *
+ * Copyright (C) 2007-2009 Neil Brown <neilb@suse.de>
+ * Copyright (C) 2007-2009 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/*
+ * md array manager.
+ * When md arrays have user-space managed metadata, this is the program
+ * that does the managing.
+ *
+ * Given one argument: the name of the array (e.g. /dev/md0) that is
+ * the container.
+ * We fork off a helper that runs high priority and mlocked. It responds to
+ * device failures and other events that might stop writeout, or that are
+ * trivial to deal with.
+ * The main thread then watches for new arrays being created in the container
+ * and starts monitoring them too ... along with a few other tasks.
+ *
+ * The main thread communicates with the priority thread by writing over
+ * a pipe.
+ * Separate programs can communicate with the main thread via Unix-domain
+ * socket.
+ * The two threads share address space and open file table.
+ *
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/mman.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <dirent.h>
+#ifdef USE_PTHREADS
+#include <pthread.h>
+#else
+#include <sched.h>
+#endif
+
+#include "mdadm.h"
+#include "mdmon.h"
+
+char const Name[] = "mdmon";
+
+struct active_array *discard_this;
+struct active_array *pending_discard;
+
+int mon_tid, mgr_tid;
+
+int sigterm;
+
+#ifdef USE_PTHREADS
+static void *run_child(void *v)
+{
+ struct supertype *c = v;
+
+ mon_tid = syscall(SYS_gettid);
+ do_monitor(c);
+ return 0;
+}
+
+static int clone_monitor(struct supertype *container)
+{
+ pthread_attr_t attr;
+ pthread_t thread;
+ int rc;
+
+ mon_tid = -1;
+ pthread_attr_init(&attr);
+ pthread_attr_setstacksize(&attr, 4096);
+ pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+ rc = pthread_create(&thread, &attr, run_child, container);
+ if (rc)
+ return rc;
+ while (mon_tid == -1)
+ usleep(10);
+ pthread_attr_destroy(&attr);
+
+ mgr_tid = syscall(SYS_gettid);
+
+ return mon_tid;
+}
+#else /* USE_PTHREADS */
+static int run_child(void *v)
+{
+ struct supertype *c = v;
+
+ do_monitor(c);
+ return 0;
+}
+
+#ifdef __ia64__
+int __clone2(int (*fn)(void *),
+ void *child_stack_base, size_t stack_size,
+ int flags, void *arg, ...
+ /* pid_t *pid, struct user_desc *tls, pid_t *ctid */ );
+#endif
+static int clone_monitor(struct supertype *container)
+{
+ static char stack[4096];
+
+#ifdef __ia64__
+ mon_tid = __clone2(run_child, stack, sizeof(stack),
+ CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD,
+ container);
+#else
+ mon_tid = clone(run_child, stack+4096-64,
+ CLONE_FS|CLONE_FILES|CLONE_VM|CLONE_SIGHAND|CLONE_THREAD,
+ container);
+#endif
+
+ mgr_tid = syscall(SYS_gettid);
+
+ return mon_tid;
+}
+#endif /* USE_PTHREADS */
+
+static int make_pidfile(char *devname)
+{
+ char path[100];
+ char pid[10];
+ int fd;
+ int n;
+
+ if (mkdir(MDMON_DIR, 0755) < 0 &&
+ errno != EEXIST)
+ return -errno;
+ sprintf(path, "%s/%s.pid", MDMON_DIR, devname);
+
+ fd = open(path, O_RDWR|O_CREAT|O_EXCL, 0600);
+ if (fd < 0)
+ return -errno;
+ sprintf(pid, "%d\n", getpid());
+ n = write(fd, pid, strlen(pid));
+ close(fd);
+ if (n < 0)
+ return -errno;
+ return 0;
+}
+
+static void try_kill_monitor(pid_t pid, char *devname, int sock)
+{
+ char buf[100];
+ int fd;
+ int n;
+ long fl;
+ int rv;
+
+ /* first rule of survival... don't off yourself */
+ if (pid == getpid())
+ return;
+
+ /* kill this process if it is mdmon */
+ sprintf(buf, "/proc/%lu/cmdline", (unsigned long) pid);
+ fd = open(buf, O_RDONLY);
+ if (fd < 0)
+ return;
+
+ n = read(fd, buf, sizeof(buf)-1);
+ buf[sizeof(buf)-1] = 0;
+ close(fd);
+
+ if (n < 0 || !(strstr(buf, "mdmon") ||
+ strstr(buf, "@dmon")))
+ return;
+
+ kill(pid, SIGTERM);
+
+ if (sock < 0)
+ return;
+
+ /* Wait for monitor to exit by reading from the socket, after
+ * clearing the non-blocking flag */
+ fl = fcntl(sock, F_GETFL, 0);
+ fl &= ~O_NONBLOCK;
+ fcntl(sock, F_SETFL, fl);
+ n = read(sock, buf, 100);
+
+ /* If there is I/O going on it might took some time to get to
+ * clean state. Wait for monitor to exit fully to avoid races.
+ * Ping it with SIGUSR1 in case that it is sleeping */
+ for (n = 0; n < 25; n++) {
+ rv = kill(pid, SIGUSR1);
+ if (rv < 0)
+ break;
+ usleep(200000);
+ }
+}
+
+void remove_pidfile(char *devname)
+{
+ char buf[100];
+
+ sprintf(buf, "%s/%s.pid", MDMON_DIR, devname);
+ unlink(buf);
+ sprintf(buf, "%s/%s.sock", MDMON_DIR, devname);
+ unlink(buf);
+}
+
+static int make_control_sock(char *devname)
+{
+ char path[100];
+ int sfd;
+ long fl;
+ struct sockaddr_un addr;
+
+ if (sigterm)
+ return -1;
+
+ sprintf(path, "%s/%s.sock", MDMON_DIR, devname);
+ unlink(path);
+ sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
+ if (sfd < 0)
+ return -1;
+
+ addr.sun_family = PF_LOCAL;
+ strcpy(addr.sun_path, path);
+ umask(077); /* ensure no world write access */
+ if (bind(sfd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
+ close(sfd);
+ return -1;
+ }
+ listen(sfd, 10);
+ fl = fcntl(sfd, F_GETFL, 0);
+ fl |= O_NONBLOCK;
+ fcntl(sfd, F_SETFL, fl);
+ return sfd;
+}
+
+static void term(int sig)
+{
+ sigterm = 1;
+}
+
+static void wake_me(int sig)
+{
+
+}
+
+/* if we are debugging and starting mdmon by hand then don't fork */
+static int do_fork(void)
+{
+ #ifdef DEBUG
+ if (check_env("MDADM_NO_MDMON"))
+ return 0;
+ #endif
+
+ return 1;
+}
+
+void usage(void)
+{
+ fprintf(stderr,
+"Usage: mdmon [options] CONTAINER\n"
+"\n"
+"Options are:\n"
+" --help -h : This message\n"
+" --all -a : All devices\n"
+" --foreground -F : Run in foreground (do not fork)\n"
+" --takeover -t : Takeover container\n"
+);
+ exit(2);
+}
+
+static int mdmon(char *devnm, int must_fork, int takeover);
+
+int main(int argc, char *argv[])
+{
+ char *container_name = NULL;
+ char *devnm = NULL;
+ int status = 0;
+ int opt;
+ int all = 0;
+ int takeover = 0;
+ int dofork = 1;
+ static struct option options[] = {
+ {"all", 0, NULL, 'a'},
+ {"takeover", 0, NULL, 't'},
+ {"help", 0, NULL, 'h'},
+ {"offroot", 0, NULL, OffRootOpt},
+ {"foreground", 0, NULL, 'F'},
+ {NULL, 0, NULL, 0}
+ };
+
+ if (in_initrd()) {
+ /*
+ * set first char of argv[0] to @. This is used by
+ * systemd to signal that the task was launched from
+ * initrd/initramfs and should be preserved during shutdown
+ */
+ argv[0][0] = '@';
+ }
+
+ while ((opt = getopt_long(argc, argv, "thaF", options, NULL)) != -1) {
+ switch (opt) {
+ case 'a':
+ container_name = argv[optind-1];
+ all = 1;
+ break;
+ case 't':
+ takeover = 1;
+ break;
+ case 'F':
+ dofork = 0;
+ break;
+ case OffRootOpt:
+ argv[0][0] = '@';
+ break;
+ case 'h':
+ default:
+ usage();
+ break;
+ }
+ }
+
+ if (all == 0 && container_name == NULL) {
+ if (argv[optind])
+ container_name = argv[optind];
+ }
+
+ if (container_name == NULL)
+ usage();
+
+ if (argc - optind > 1)
+ usage();
+
+ if (strcmp(container_name, "/proc/mdstat") == 0)
+ all = 1;
+
+ if (all) {
+ struct mdstat_ent *mdstat, *e;
+ int container_len = strlen(container_name);
+
+ /* launch an mdmon instance for each container found */
+ mdstat = mdstat_read(0, 0);
+ for (e = mdstat; e; e = e->next) {
+ if (e->metadata_version &&
+ strncmp(e->metadata_version, "external:", 9) == 0 &&
+ !is_subarray(&e->metadata_version[9])) {
+ /* update cmdline so this mdmon instance can be
+ * distinguished from others in a call to ps(1)
+ */
+ if (strlen(e->devnm) <= (unsigned)container_len) {
+ memset(container_name, 0, container_len);
+ sprintf(container_name, "%s", e->devnm);
+ }
+ status |= mdmon(e->devnm, 1, takeover);
+ }
+ }
+ free_mdstat(mdstat);
+
+ return status;
+ } else if (strncmp(container_name, "md", 2) == 0) {
+ int id = devnm2devid(container_name);
+ if (id)
+ devnm = container_name;
+ } else {
+ struct stat st;
+
+ if (stat(container_name, &st) == 0)
+ devnm = xstrdup(stat2devnm(&st));
+ }
+
+ if (!devnm) {
+ pr_err("%s is not a valid md device name\n",
+ container_name);
+ exit(1);
+ }
+ return mdmon(devnm, dofork && do_fork(), takeover);
+}
+
+static int mdmon(char *devnm, int must_fork, int takeover)
+{
+ int mdfd;
+ struct mdinfo *mdi, *di;
+ struct supertype *container;
+ sigset_t set;
+ struct sigaction act;
+ int pfd[2];
+ int status;
+ int ignore;
+ pid_t victim = -1;
+ int victim_sock = -1;
+
+ dprintf("starting mdmon for %s\n", devnm);
+
+ mdfd = open_dev(devnm);
+ if (mdfd < 0) {
+ pr_err("%s: %s\n", devnm, strerror(errno));
+ return 1;
+ }
+
+ /* Fork, and have the child tell us when they are ready */
+ if (must_fork) {
+ if (pipe(pfd) != 0) {
+ pr_err("failed to create pipe\n");
+ return 1;
+ }
+ switch(fork()) {
+ case -1:
+ pr_err("failed to fork: %s\n", strerror(errno));
+ return 1;
+ case 0: /* child */
+ close(pfd[0]);
+ break;
+ default: /* parent */
+ close(pfd[1]);
+ if (read(pfd[0], &status, sizeof(status)) != sizeof(status)) {
+ wait(&status);
+ status = WEXITSTATUS(status);
+ }
+ close(pfd[0]);
+ return status;
+ }
+ } else
+ pfd[0] = pfd[1] = -1;
+
+ container = xcalloc(1, sizeof(*container));
+ strcpy(container->devnm, devnm);
+ container->arrays = NULL;
+ container->sock = -1;
+
+ mdi = sysfs_read(mdfd, container->devnm, GET_VERSION|GET_LEVEL|GET_DEVS);
+
+ if (!mdi) {
+ pr_err("failed to load sysfs info for %s\n", container->devnm);
+ exit(3);
+ }
+ if (mdi->array.level != UnSet) {
+ pr_err("%s is not a container - cannot monitor\n", devnm);
+ exit(3);
+ }
+ if (mdi->array.major_version != -1 ||
+ mdi->array.minor_version != -2) {
+ pr_err("%s does not use external metadata - cannot monitor\n",
+ devnm);
+ exit(3);
+ }
+
+ container->ss = version_to_superswitch(mdi->text_version);
+ if (container->ss == NULL) {
+ pr_err("%s uses unsupported metadata: %s\n",
+ devnm, mdi->text_version);
+ exit(3);
+ }
+
+ container->devs = NULL;
+ for (di = mdi->devs; di; di = di->next) {
+ struct mdinfo *cd = xmalloc(sizeof(*cd));
+ *cd = *di;
+ cd->next = container->devs;
+ container->devs = cd;
+ }
+ sysfs_free(mdi);
+
+ /* SIGUSR is sent between parent and child. So both block it
+ * and enable it only with pselect.
+ */
+ sigemptyset(&set);
+ sigaddset(&set, SIGUSR1);
+ sigaddset(&set, SIGTERM);
+ sigprocmask(SIG_BLOCK, &set, NULL);
+ act.sa_handler = wake_me;
+ act.sa_flags = 0;
+ sigaction(SIGUSR1, &act, NULL);
+ act.sa_handler = term;
+ sigaction(SIGTERM, &act, NULL);
+ act.sa_handler = SIG_IGN;
+ sigaction(SIGPIPE, &act, NULL);
+
+ victim = mdmon_pid(container->devnm);
+ if (victim >= 0)
+ victim_sock = connect_monitor(container->devnm);
+
+ ignore = chdir("/");
+ if (!takeover && victim > 0 && victim_sock >= 0) {
+ if (fping_monitor(victim_sock) == 0) {
+ pr_err("%s already managed\n", container->devnm);
+ exit(3);
+ }
+ close(victim_sock);
+ victim_sock = -1;
+ }
+ if (container->ss->load_container(container, mdfd, devnm)) {
+ pr_err("Cannot load metadata for %s\n", devnm);
+ exit(3);
+ }
+ close(mdfd);
+
+ /* Ok, this is close enough. We can say goodbye to our parent now.
+ */
+ if (victim > 0)
+ remove_pidfile(devnm);
+ if (make_pidfile(devnm) < 0) {
+ exit(3);
+ }
+ container->sock = make_control_sock(devnm);
+
+ status = 0;
+ if (pfd[1] >= 0) {
+ if (write(pfd[1], &status, sizeof(status)) < 0)
+ pr_err("failed to notify our parent: %d\n",
+ getppid());
+ close(pfd[1]);
+ }
+
+ mlockall(MCL_CURRENT | MCL_FUTURE);
+
+ if (clone_monitor(container) < 0) {
+ pr_err("failed to start monitor process: %s\n",
+ strerror(errno));
+ exit(2);
+ }
+
+ if (victim > 0) {
+ try_kill_monitor(victim, container->devnm, victim_sock);
+ if (victim_sock >= 0)
+ close(victim_sock);
+ }
+
+ setsid();
+ manage_fork_fds(0);
+
+ /* This silliness is to stop the compiler complaining
+ * that we ignore 'ignore'
+ */
+ if (ignore)
+ ignore++;
+
+ do_manager(container);
+
+ exit(0);
+}
+
+/* Some stub functions so super-* can link with us */
+int child_monitor(int afd, struct mdinfo *sra, struct reshape *reshape,
+ struct supertype *st, unsigned long blocks,
+ int *fds, unsigned long long *offsets,
+ int dests, int *destfd, unsigned long long *destoffsets)
+{
+ return 0;
+}
+
+int restore_stripes(int *dest, unsigned long long *offsets,
+ int raid_disks, int chunk_size, int level, int layout,
+ int source, unsigned long long read_offset,
+ unsigned long long start, unsigned long long length,
+ char *src_buf)
+{
+ return 1;
+}
+
+int save_stripes(int *source, unsigned long long *offsets,
+ int raid_disks, int chunk_size, int level, int layout,
+ int nwrites, int *dest,
+ unsigned long long start, unsigned long long length,
+ char *buf)
+{
+ return 0;
+}
+
+struct superswitch super0 = {
+ .name = "0.90",
+};
+struct superswitch super1 = {
+ .name = "1.x",
+};