diff options
Diffstat (limited to 'monitor.c')
| -rw-r--r-- | monitor.c | 712 |
1 files changed, 712 insertions, 0 deletions
diff --git a/monitor.c b/monitor.c new file mode 100644 index 00000000..870cc1a7 --- /dev/null +++ b/monitor.c @@ -0,0 +1,712 @@ +/* + * 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("Invalid fd %d\n", fd); + return; + } + if (st.st_nlink == 0) { + dprintf("fd %d was deleted\n", 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("Failed to read resync_start (%d)\n", 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("(%d): %ld.%06ld state:%s prev:%s action:%s prev: %s start:%llu\n", + 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("(%d): state:%s action:%s next(", 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_cont(" 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_cont(" action:%s", sync_actions[a->next_action]); + } + for (mdi = a->info.devs; mdi ; mdi = mdi->next) { + if (mdi->next_state & DS_UNBLOCK) { + dprintf_cont(" %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_cont(" %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_cont(" %d:+in_sync", mdi->disk.raid_disk); + } + } + dprintf_cont(" )\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); +} |