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-rw-r--r--monitor.c713
1 files changed, 713 insertions, 0 deletions
diff --git a/monitor.c b/monitor.c
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index 00000000..f81e7075
--- /dev/null
+++ b/monitor.c
@@ -0,0 +1,713 @@
+/*
+ * 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.
+ */
+
+#include "mdadm.h"
+#include "mdmon.h"
+#include <sys/syscall.h>
+#include <sys/select.h>
+#include <signal.h>
+
+static char *array_states[] = {
+ "clear", "inactive", "suspended", "readonly", "read-auto",
+ "clean", "active", "write-pending", "active-idle", NULL };
+static char *sync_actions[] = {
+ "idle", "reshape", "resync", "recover", "check", "repair", NULL
+};
+
+static int write_attr(char *attr, int fd)
+{
+ return write(fd, attr, strlen(attr));
+}
+
+static void add_fd(fd_set *fds, int *maxfd, int fd)
+{
+ struct stat st;
+ if (fd < 0)
+ return;
+ if (fstat(fd, &st) == -1) {
+ dprintf("%s: Invalid fd %d\n", __func__, fd);
+ return;
+ }
+ if (st.st_nlink == 0) {
+ dprintf("%s: fd %d was deleted\n", __func__, fd);
+ return;
+ }
+ if (fd > *maxfd)
+ *maxfd = fd;
+ FD_SET(fd, fds);
+}
+
+static int read_attr(char *buf, int len, int fd)
+{
+ int n;
+
+ if (fd < 0) {
+ buf[0] = 0;
+ return 0;
+ }
+ lseek(fd, 0, 0);
+ n = read(fd, buf, len - 1);
+
+ if (n <= 0) {
+ buf[0] = 0;
+ return 0;
+ }
+ buf[n] = 0;
+ if (buf[n-1] == '\n')
+ buf[n-1] = 0;
+ return n;
+}
+
+static void read_resync_start(int fd, unsigned long long *v)
+{
+ char buf[30];
+ int n;
+
+ n = read_attr(buf, 30, fd);
+ if (n <= 0) {
+ dprintf("%s: Failed to read resync_start (%d)\n",
+ __func__, fd);
+ return;
+ }
+ if (strncmp(buf, "none", 4) == 0)
+ *v = MaxSector;
+ else
+ *v = strtoull(buf, NULL, 10);
+}
+
+static unsigned long long read_sync_completed(int fd)
+{
+ unsigned long long val;
+ char buf[50];
+ int n;
+ char *ep;
+
+ n = read_attr(buf, 50, fd);
+
+ if (n <= 0)
+ return 0;
+ buf[n] = 0;
+ val = strtoull(buf, &ep, 0);
+ if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
+ return 0;
+ return val;
+}
+
+static enum array_state read_state(int fd)
+{
+ char buf[20];
+ int n = read_attr(buf, 20, fd);
+
+ if (n <= 0)
+ return bad_word;
+ return (enum array_state) sysfs_match_word(buf, array_states);
+}
+
+static enum sync_action read_action( int fd)
+{
+ char buf[20];
+ int n = read_attr(buf, 20, fd);
+
+ if (n <= 0)
+ return bad_action;
+ return (enum sync_action) sysfs_match_word(buf, sync_actions);
+}
+
+int read_dev_state(int fd)
+{
+ char buf[60];
+ int n = read_attr(buf, 60, fd);
+ char *cp;
+ int rv = 0;
+
+ if (n <= 0)
+ return 0;
+
+ cp = buf;
+ while (cp) {
+ if (sysfs_attr_match(cp, "faulty"))
+ rv |= DS_FAULTY;
+ if (sysfs_attr_match(cp, "in_sync"))
+ rv |= DS_INSYNC;
+ if (sysfs_attr_match(cp, "write_mostly"))
+ rv |= DS_WRITE_MOSTLY;
+ if (sysfs_attr_match(cp, "spare"))
+ rv |= DS_SPARE;
+ if (sysfs_attr_match(cp, "blocked"))
+ rv |= DS_BLOCKED;
+ cp = strchr(cp, ',');
+ if (cp)
+ cp++;
+ }
+ return rv;
+}
+
+static void signal_manager(void)
+{
+ /* tgkill(getpid(), mon_tid, SIGUSR1); */
+ int pid = getpid();
+ syscall(SYS_tgkill, pid, mgr_tid, SIGUSR1);
+}
+
+/* Monitor a set of active md arrays - all of which share the
+ * same metadata - and respond to events that require
+ * metadata update.
+ *
+ * New arrays are detected by another thread which allocates
+ * required memory and attaches the data structure to our list.
+ *
+ * Events:
+ * Array stops.
+ * This is detected by array_state going to 'clear' or 'inactive'.
+ * while we thought it was active.
+ * Response is to mark metadata as clean and 'clear' the array(??)
+ * write-pending
+ * array_state if 'write-pending'
+ * We mark metadata as 'dirty' then set array to 'active'.
+ * active_idle
+ * Either ignore, or mark clean, then mark metadata as clean.
+ *
+ * device fails
+ * detected by rd-N/state reporting "faulty"
+ * mark device as 'failed' in metadata, let the kernel release the
+ * device by writing '-blocked' to rd/state, and finally write 'remove' to
+ * rd/state. Before a disk can be replaced it must be failed and removed
+ * from all container members, this will be preemptive for the other
+ * arrays... safe?
+ *
+ * sync completes
+ * sync_action was 'resync' and becomes 'idle' and resync_start becomes
+ * MaxSector
+ * Notify metadata that sync is complete.
+ *
+ * recovery completes
+ * sync_action changes from 'recover' to 'idle'
+ * Check each device state and mark metadata if 'faulty' or 'in_sync'.
+ *
+ * deal with resync
+ * This only happens on finding a new array... mdadm will have set
+ * 'resync_start' to the correct value. If 'resync_start' indicates that an
+ * resync needs to occur set the array to the 'active' state rather than the
+ * initial read-auto state.
+ *
+ *
+ *
+ * We wait for a change (poll/select) on array_state, sync_action, and
+ * each rd-X/state file.
+ * When we get any change, we check everything. So read each state file,
+ * then decide what to do.
+ *
+ * The core action is to write new metadata to all devices in the array.
+ * This is done at most once on any wakeup.
+ * After that we might:
+ * - update the array_state
+ * - set the role of some devices.
+ * - request a sync_action
+ *
+ */
+
+#define ARRAY_DIRTY 1
+#define ARRAY_BUSY 2
+static int read_and_act(struct active_array *a)
+{
+ unsigned long long sync_completed;
+ int check_degraded = 0;
+ int check_reshape = 0;
+ int deactivate = 0;
+ struct mdinfo *mdi;
+ int ret = 0;
+ int count = 0;
+ struct timeval tv;
+
+ a->next_state = bad_word;
+ a->next_action = bad_action;
+
+ a->curr_state = read_state(a->info.state_fd);
+ a->curr_action = read_action(a->action_fd);
+ if (a->curr_state != clear)
+ /*
+ * In "clear" state, resync_start may wrongly be set to "0"
+ * when the kernel called md_clean but didn't remove the
+ * sysfs attributes yet
+ */
+ read_resync_start(a->resync_start_fd, &a->info.resync_start);
+ sync_completed = read_sync_completed(a->sync_completed_fd);
+ for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
+ mdi->next_state = 0;
+ mdi->curr_state = 0;
+ if (mdi->state_fd >= 0) {
+ read_resync_start(mdi->recovery_fd,
+ &mdi->recovery_start);
+ mdi->curr_state = read_dev_state(mdi->state_fd);
+ }
+ }
+
+ gettimeofday(&tv, NULL);
+ dprintf("%s(%d): %ld.%06ld state:%s prev:%s action:%s prev: %s start:%llu\n",
+ __func__, a->info.container_member,
+ tv.tv_sec, tv.tv_usec,
+ array_states[a->curr_state],
+ array_states[a->prev_state],
+ sync_actions[a->curr_action],
+ sync_actions[a->prev_action],
+ a->info.resync_start
+ );
+
+ if ((a->curr_state == bad_word || a->curr_state <= inactive) &&
+ a->prev_state > inactive) {
+ /* array has been stopped */
+ a->container->ss->set_array_state(a, 1);
+ a->next_state = clear;
+ deactivate = 1;
+ }
+ if (a->curr_state == write_pending) {
+ a->container->ss->set_array_state(a, 0);
+ a->next_state = active;
+ ret |= ARRAY_DIRTY;
+ }
+ if (a->curr_state == active_idle) {
+ /* Set array to 'clean' FIRST, then mark clean
+ * in the metadata
+ */
+ a->next_state = clean;
+ ret |= ARRAY_DIRTY;
+ }
+ if (a->curr_state == clean) {
+ a->container->ss->set_array_state(a, 1);
+ }
+ if (a->curr_state == active ||
+ a->curr_state == suspended)
+ ret |= ARRAY_DIRTY;
+ if (a->curr_state == readonly) {
+ /* Well, I'm ready to handle things. If readonly
+ * wasn't requested, transition to read-auto.
+ */
+ char buf[64];
+ read_attr(buf, sizeof(buf), a->metadata_fd);
+ if (strncmp(buf, "external:-", 10) == 0) {
+ /* explicit request for readonly array. Leave it alone */
+ ;
+ } else {
+ if (a->container->ss->set_array_state(a, 2))
+ a->next_state = read_auto; /* array is clean */
+ else {
+ a->next_state = active; /* Now active for recovery etc */
+ ret |= ARRAY_DIRTY;
+ }
+ }
+ }
+
+ if (!deactivate &&
+ a->curr_action == idle &&
+ a->prev_action == resync) {
+ /* A resync has finished. The endpoint is recorded in
+ * 'sync_start'. We don't update the metadata
+ * until the array goes inactive or readonly though.
+ * Just check if we need to fiddle spares.
+ */
+ a->container->ss->set_array_state(a, a->curr_state <= clean);
+ check_degraded = 1;
+ }
+
+ if (!deactivate &&
+ a->curr_action == idle &&
+ a->prev_action == recover) {
+ /* A recovery has finished. Some disks may be in sync now,
+ * and the array may no longer be degraded
+ */
+ for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
+ a->container->ss->set_disk(a, mdi->disk.raid_disk,
+ mdi->curr_state);
+ if (! (mdi->curr_state & DS_INSYNC))
+ check_degraded = 1;
+ count++;
+ }
+ if (count != a->info.array.raid_disks)
+ check_degraded = 1;
+ }
+
+ if (!deactivate &&
+ a->curr_action == reshape &&
+ a->prev_action != reshape)
+ /* reshape was requested by mdadm. Need to see if
+ * new devices have been added. Manager does that
+ * when it sees check_reshape
+ */
+ check_reshape = 1;
+
+ /* Check for failures and if found:
+ * 1/ Record the failure in the metadata and unblock the device.
+ * FIXME update the kernel to stop notifying on failed drives when
+ * the array is readonly and we have cleared 'blocked'
+ * 2/ Try to remove the device if the array is writable, or can be
+ * made writable.
+ */
+ for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
+ if (mdi->curr_state & DS_FAULTY) {
+ a->container->ss->set_disk(a, mdi->disk.raid_disk,
+ mdi->curr_state);
+ check_degraded = 1;
+ if (mdi->curr_state & DS_BLOCKED)
+ mdi->next_state |= DS_UNBLOCK;
+ if (a->curr_state == read_auto) {
+ a->container->ss->set_array_state(a, 0);
+ a->next_state = active;
+ }
+ if (a->curr_state > readonly)
+ mdi->next_state |= DS_REMOVE;
+ }
+ }
+
+ /* Check for recovery checkpoint notifications. We need to be a
+ * minimum distance away from the last checkpoint to prevent
+ * over checkpointing. Note reshape checkpointing is handled
+ * in the second branch.
+ */
+ if (sync_completed > a->last_checkpoint &&
+ sync_completed - a->last_checkpoint > a->info.component_size >> 4 &&
+ a->curr_action > reshape) {
+ /* A (non-reshape) sync_action has reached a checkpoint.
+ * Record the updated position in the metadata
+ */
+ a->last_checkpoint = sync_completed;
+ a->container->ss->set_array_state(a, a->curr_state <= clean);
+ } else if ((a->curr_action == idle && a->prev_action == reshape) ||
+ (a->curr_action == reshape
+ && sync_completed > a->last_checkpoint) ) {
+ /* Reshape has progressed or completed so we need to
+ * update the array state - and possibly the array size
+ */
+ if (sync_completed != 0)
+ a->last_checkpoint = sync_completed;
+ /* We might need to update last_checkpoint depending on
+ * the reason that reshape finished.
+ * if array reshape is really finished:
+ * set check point to the end, this allows
+ * set_array_state() to finalize reshape in metadata
+ * if reshape if broken: do not set checkpoint to the end
+ * this allows for reshape restart from checkpoint
+ */
+ if ((a->curr_action != reshape) &&
+ (a->prev_action == reshape)) {
+ char buf[40];
+ if ((sysfs_get_str(&a->info, NULL,
+ "reshape_position",
+ buf,
+ sizeof(buf)) >= 0) &&
+ strncmp(buf, "none", 4) == 0)
+ a->last_checkpoint = a->info.component_size;
+ }
+ a->container->ss->set_array_state(a, a->curr_state <= clean);
+ a->last_checkpoint = sync_completed;
+ }
+
+ if (sync_completed > a->last_checkpoint)
+ a->last_checkpoint = sync_completed;
+
+ a->container->ss->sync_metadata(a->container);
+ dprintf("%s(%d): state:%s action:%s next(", __func__, a->info.container_member,
+ array_states[a->curr_state], sync_actions[a->curr_action]);
+
+ /* Effect state changes in the array */
+ if (a->next_state != bad_word) {
+ dprintf(" state:%s", array_states[a->next_state]);
+ write_attr(array_states[a->next_state], a->info.state_fd);
+ }
+ if (a->next_action != bad_action) {
+ write_attr(sync_actions[a->next_action], a->action_fd);
+ dprintf(" action:%s", sync_actions[a->next_action]);
+ }
+ for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
+ if (mdi->next_state & DS_UNBLOCK) {
+ dprintf(" %d:-blocked", mdi->disk.raid_disk);
+ write_attr("-blocked", mdi->state_fd);
+ }
+
+ if ((mdi->next_state & DS_REMOVE) && mdi->state_fd >= 0) {
+ int remove_result;
+
+ /* The kernel may not be able to immediately remove the
+ * disk. In that case we wait a little while and
+ * try again.
+ */
+ remove_result = write_attr("remove", mdi->state_fd);
+ if (remove_result > 0) {
+ dprintf(" %d:removed", mdi->disk.raid_disk);
+ close(mdi->state_fd);
+ close(mdi->recovery_fd);
+ mdi->state_fd = -1;
+ } else
+ ret |= ARRAY_BUSY;
+ }
+ if (mdi->next_state & DS_INSYNC) {
+ write_attr("+in_sync", mdi->state_fd);
+ dprintf(" %d:+in_sync", mdi->disk.raid_disk);
+ }
+ }
+ dprintf(" )\n");
+
+ /* move curr_ to prev_ */
+ a->prev_state = a->curr_state;
+
+ a->prev_action = a->curr_action;
+
+ for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
+ mdi->prev_state = mdi->curr_state;
+ mdi->next_state = 0;
+ }
+
+ if (check_degraded || check_reshape) {
+ /* manager will do the actual check */
+ if (check_degraded)
+ a->check_degraded = 1;
+ if (check_reshape)
+ a->check_reshape = 1;
+ signal_manager();
+ }
+
+ if (deactivate)
+ a->container = NULL;
+
+ return ret;
+}
+
+static struct mdinfo *
+find_device(struct active_array *a, int major, int minor)
+{
+ struct mdinfo *mdi;
+
+ for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
+ if (mdi->disk.major == major && mdi->disk.minor == minor)
+ return mdi;
+
+ return NULL;
+}
+
+static void reconcile_failed(struct active_array *aa, struct mdinfo *failed)
+{
+ struct active_array *a;
+ struct mdinfo *victim;
+
+ for (a = aa; a; a = a->next) {
+ if (!a->container || a->to_remove)
+ continue;
+ victim = find_device(a, failed->disk.major, failed->disk.minor);
+ if (!victim)
+ continue;
+
+ if (!(victim->curr_state & DS_FAULTY))
+ write_attr("faulty", victim->state_fd);
+ }
+}
+
+#ifdef DEBUG
+static void dprint_wake_reasons(fd_set *fds)
+{
+ int i;
+ char proc_path[256];
+ char link[256];
+ char *basename;
+ int rv;
+
+ fprintf(stderr, "monitor: wake ( ");
+ for (i = 0; i < FD_SETSIZE; i++) {
+ if (FD_ISSET(i, fds)) {
+ sprintf(proc_path, "/proc/%d/fd/%d",
+ (int) getpid(), i);
+
+ rv = readlink(proc_path, link, sizeof(link) - 1);
+ if (rv < 0) {
+ fprintf(stderr, "%d:unknown ", i);
+ continue;
+ }
+ link[rv] = '\0';
+ basename = strrchr(link, '/');
+ fprintf(stderr, "%d:%s ",
+ i, basename ? ++basename : link);
+ }
+ }
+ fprintf(stderr, ")\n");
+}
+#endif
+
+int monitor_loop_cnt;
+
+static int wait_and_act(struct supertype *container, int nowait)
+{
+ fd_set rfds;
+ int maxfd = 0;
+ struct active_array **aap = &container->arrays;
+ struct active_array *a, **ap;
+ int rv;
+ struct mdinfo *mdi;
+ static unsigned int dirty_arrays = ~0; /* start at some non-zero value */
+
+ FD_ZERO(&rfds);
+
+ for (ap = aap ; *ap ;) {
+ a = *ap;
+ /* once an array has been deactivated we want to
+ * ask the manager to discard it.
+ */
+ if (!a->container || a->to_remove) {
+ if (discard_this) {
+ ap = &(*ap)->next;
+ continue;
+ }
+ *ap = a->next;
+ a->next = NULL;
+ discard_this = a;
+ signal_manager();
+ continue;
+ }
+
+ add_fd(&rfds, &maxfd, a->info.state_fd);
+ add_fd(&rfds, &maxfd, a->action_fd);
+ add_fd(&rfds, &maxfd, a->sync_completed_fd);
+ for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
+ add_fd(&rfds, &maxfd, mdi->state_fd);
+
+ ap = &(*ap)->next;
+ }
+
+ if (manager_ready && (*aap == NULL || (sigterm && !dirty_arrays))) {
+ /* No interesting arrays, or we have been told to
+ * terminate and everything is clean. Lets see about
+ * exiting. Note that blocking at this point is not a
+ * problem as there are no active arrays, there is
+ * nothing that we need to be ready to do.
+ */
+ int fd;
+ if (sigterm)
+ fd = open_dev_excl(container->devnm);
+ else
+ fd = open_dev_flags(container->devnm, O_RDONLY|O_EXCL);
+ if (fd >= 0 || errno != EBUSY) {
+ /* OK, we are safe to leave */
+ if (sigterm && !dirty_arrays)
+ dprintf("caught sigterm, all clean... exiting\n");
+ else
+ dprintf("no arrays to monitor... exiting\n");
+ if (!sigterm)
+ /* On SIGTERM, someone (the take-over mdmon) will
+ * clean up
+ */
+ remove_pidfile(container->devnm);
+ exit_now = 1;
+ signal_manager();
+ close(fd);
+ exit(0);
+ }
+ }
+
+ if (!nowait) {
+ sigset_t set;
+ struct timespec ts;
+ ts.tv_sec = 24*3600;
+ ts.tv_nsec = 0;
+ if (*aap == NULL || container->retry_soon) {
+ /* just waiting to get O_EXCL access */
+ ts.tv_sec = 0;
+ ts.tv_nsec = 20000000ULL;
+ }
+ sigprocmask(SIG_UNBLOCK, NULL, &set);
+ sigdelset(&set, SIGUSR1);
+ monitor_loop_cnt |= 1;
+ rv = pselect(maxfd+1, NULL, NULL, &rfds, &ts, &set);
+ monitor_loop_cnt += 1;
+ if (rv == -1) {
+ if (errno == EINTR) {
+ rv = 0;
+ dprintf("monitor: caught signal\n");
+ } else
+ dprintf("monitor: error %d in pselect\n",
+ errno);
+ }
+ #ifdef DEBUG
+ else
+ dprint_wake_reasons(&rfds);
+ #endif
+ container->retry_soon = 0;
+ }
+
+ if (update_queue) {
+ struct metadata_update *this;
+
+ for (this = update_queue; this ; this = this->next)
+ container->ss->process_update(container, this);
+
+ update_queue_handled = update_queue;
+ update_queue = NULL;
+ signal_manager();
+ container->ss->sync_metadata(container);
+ }
+
+ rv = 0;
+ dirty_arrays = 0;
+ for (a = *aap; a ; a = a->next) {
+
+ if (a->replaces && !discard_this) {
+ struct active_array **ap;
+ for (ap = &a->next; *ap && *ap != a->replaces;
+ ap = & (*ap)->next)
+ ;
+ if (*ap)
+ *ap = (*ap)->next;
+ discard_this = a->replaces;
+ a->replaces = NULL;
+ /* FIXME check if device->state_fd need to be cleared?*/
+ signal_manager();
+ }
+ if (a->container && !a->to_remove) {
+ int ret = read_and_act(a);
+ rv |= 1;
+ dirty_arrays += !!(ret & ARRAY_DIRTY);
+ /* when terminating stop manipulating the array after it
+ * is clean, but make sure read_and_act() is given a
+ * chance to handle 'active_idle'
+ */
+ if (sigterm && !(ret & ARRAY_DIRTY))
+ a->container = NULL; /* stop touching this array */
+ if (ret & ARRAY_BUSY)
+ container->retry_soon = 1;
+ }
+ }
+
+ /* propagate failures across container members */
+ for (a = *aap; a ; a = a->next) {
+ if (!a->container || a->to_remove)
+ continue;
+ for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
+ if (mdi->curr_state & DS_FAULTY)
+ reconcile_failed(*aap, mdi);
+ }
+
+ return rv;
+}
+
+void do_monitor(struct supertype *container)
+{
+ int rv;
+ int first = 1;
+ do {
+ rv = wait_and_act(container, first);
+ first = 0;
+ } while (rv >= 0);
+}