524 lines
12 KiB
C
524 lines
12 KiB
C
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#include "mdadm.h"
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#include "mdmon.h"
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#include <sys/syscall.h>
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#include <sys/select.h>
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#include <signal.h>
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static char *array_states[] = {
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"clear", "inactive", "suspended", "readonly", "read-auto",
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"clean", "active", "write-pending", "active-idle", NULL };
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static char *sync_actions[] = {
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"idle", "reshape", "resync", "recover", "check", "repair", NULL
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};
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static int write_attr(char *attr, int fd)
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{
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return write(fd, attr, strlen(attr));
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}
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static void add_fd(fd_set *fds, int *maxfd, int fd)
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{
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if (fd < 0)
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return;
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if (fd > *maxfd)
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*maxfd = fd;
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FD_SET(fd, fds);
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}
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static int read_attr(char *buf, int len, int fd)
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{
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int n;
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if (fd < 0) {
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buf[0] = 0;
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return 0;
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}
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lseek(fd, 0, 0);
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n = read(fd, buf, len - 1);
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if (n <= 0) {
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buf[0] = 0;
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return 0;
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}
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buf[n] = 0;
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if (buf[n-1] == '\n')
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buf[n-1] = 0;
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return n;
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}
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int get_resync_start(struct active_array *a)
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{
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char buf[30];
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int n;
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n = read_attr(buf, 30, a->resync_start_fd);
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if (n <= 0)
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return n;
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a->resync_start = strtoull(buf, NULL, 10);
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return 1;
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}
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static int attr_match(const char *attr, const char *str)
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{
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/* See if attr, read from a sysfs file, matches
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* str. They must either be the same, or attr can
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* have a trailing newline or comma
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*/
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while (*attr && *str && *attr == *str) {
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attr++;
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str++;
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}
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if (*str || (*attr && *attr != ',' && *attr != '\n'))
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return 0;
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return 1;
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}
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static int match_word(const char *word, char **list)
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{
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int n;
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for (n=0; list[n]; n++)
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if (attr_match(word, list[n]))
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break;
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return n;
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}
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static enum array_state read_state(int fd)
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{
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char buf[20];
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int n = read_attr(buf, 20, fd);
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if (n <= 0)
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return bad_word;
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return (enum array_state) match_word(buf, array_states);
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}
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static enum sync_action read_action( int fd)
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{
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char buf[20];
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int n = read_attr(buf, 20, fd);
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if (n <= 0)
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return bad_action;
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return (enum sync_action) match_word(buf, sync_actions);
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}
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int read_dev_state(int fd)
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{
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char buf[60];
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int n = read_attr(buf, 60, fd);
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char *cp;
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int rv = 0;
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if (n <= 0)
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return 0;
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cp = buf;
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while (cp) {
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if (attr_match(cp, "faulty"))
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rv |= DS_FAULTY;
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if (attr_match(cp, "in_sync"))
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rv |= DS_INSYNC;
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if (attr_match(cp, "write_mostly"))
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rv |= DS_WRITE_MOSTLY;
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if (attr_match(cp, "spare"))
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rv |= DS_SPARE;
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if (attr_match(cp, "blocked"))
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rv |= DS_BLOCKED;
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cp = strchr(cp, ',');
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if (cp)
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cp++;
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}
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return rv;
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}
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static void signal_manager(void)
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{
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/* tgkill(getpid(), mon_tid, SIGUSR1); */
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int pid = getpid();
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syscall(SYS_tgkill, pid, mgr_tid, SIGUSR1);
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}
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/* Monitor a set of active md arrays - all of which share the
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* same metadata - and respond to events that require
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* metadata update.
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*
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* New arrays are detected by another thread which allocates
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* required memory and attaches the data structure to our list.
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*
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* Events:
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* Array stops.
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* This is detected by array_state going to 'clear' or 'inactive'.
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* while we thought it was active.
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* Response is to mark metadata as clean and 'clear' the array(??)
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* write-pending
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* array_state if 'write-pending'
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* We mark metadata as 'dirty' then set array to 'active'.
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* active_idle
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* Either ignore, or mark clean, then mark metadata as clean.
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*
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* device fails
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* detected by rd-N/state reporting "faulty"
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* mark device as 'failed' in metadata, let the kernel release the
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* device by writing '-blocked' to rd/state, and finally write 'remove' to
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* rd/state. Before a disk can be replaced it must be failed and removed
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* from all container members, this will be preemptive for the other
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* arrays... safe?
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*
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* sync completes
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* sync_action was 'resync' and becomes 'idle' and resync_start becomes
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* MaxSector
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* Notify metadata that sync is complete.
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*
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* recovery completes
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* sync_action changes from 'recover' to 'idle'
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* Check each device state and mark metadata if 'faulty' or 'in_sync'.
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*
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* deal with resync
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* This only happens on finding a new array... mdadm will have set
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* 'resync_start' to the correct value. If 'resync_start' indicates that an
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* resync needs to occur set the array to the 'active' state rather than the
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* initial read-auto state.
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*
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*
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*
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* We wait for a change (poll/select) on array_state, sync_action, and
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* each rd-X/state file.
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* When we get any change, we check everything. So read each state file,
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* then decide what to do.
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*
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* The core action is to write new metadata to all devices in the array.
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* This is done at most once on any wakeup.
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* After that we might:
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* - update the array_state
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* - set the role of some devices.
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* - request a sync_action
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*
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*/
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static int read_and_act(struct active_array *a)
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{
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int check_degraded = 0;
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int deactivate = 0;
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struct mdinfo *mdi;
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a->next_state = bad_word;
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a->next_action = bad_action;
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a->curr_state = read_state(a->info.state_fd);
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a->curr_action = read_action(a->action_fd);
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for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
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mdi->next_state = 0;
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if (mdi->state_fd >= 0)
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mdi->curr_state = read_dev_state(mdi->state_fd);
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}
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if (a->curr_state <= inactive &&
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a->prev_state > inactive) {
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/* array has been stopped */
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a->container->ss->set_array_state(a, 1);
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a->next_state = clear;
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deactivate = 1;
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}
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if (a->curr_state == write_pending) {
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get_resync_start(a);
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a->container->ss->set_array_state(a, 0);
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a->next_state = active;
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}
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if (a->curr_state == active_idle) {
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/* Set array to 'clean' FIRST, then
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* a->ss->mark_clean(a, ~0ULL);
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* just ignore for now.
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*/
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}
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if (a->curr_state == readonly) {
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/* Well, I'm ready to handle things, so
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* read-auto is OK. FIXME what if we really want
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* readonly ???
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*/
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get_resync_start(a);
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// printf("Found a readonly array at %llu\n", a->resync_start);
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if (a->resync_start == ~0ULL)
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a->next_state = read_auto; /* array is clean */
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else {
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a->container->ss->set_array_state(a, 0);
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a->next_state = active;
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}
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}
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if (!deactivate &&
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a->curr_action == idle &&
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a->prev_action == resync) {
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/* A resync has finished. The endpoint is recorded in
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* 'sync_start'. We don't update the metadata
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* until the array goes inactive or readonly though.
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* Just check if we need to fiddle spares.
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*/
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get_resync_start(a);
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a->container->ss->set_array_state(a, 0);
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check_degraded = 1;
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}
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if (!deactivate &&
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a->curr_action == idle &&
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a->prev_action == recover) {
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/* A recovery has finished. Some disks may be in sync now,
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* and the array may no longer be degraded
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*/
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for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
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a->container->ss->set_disk(a, mdi->disk.raid_disk,
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mdi->curr_state);
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if (! (mdi->curr_state & DS_INSYNC))
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check_degraded = 1;
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}
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a->container->ss->set_array_state(a, 0);
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}
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for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
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if (mdi->curr_state & DS_FAULTY) {
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a->container->ss->set_disk(a, mdi->disk.raid_disk,
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mdi->curr_state);
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check_degraded = 1;
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mdi->next_state = DS_REMOVE;
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}
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}
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a->container->ss->sync_metadata(a->container);
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dprintf("%s: update[%d]: (", __func__, a->info.container_member);
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/* Effect state changes in the array */
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if (a->next_state != bad_word) {
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dprintf(" state:%s", array_states[a->next_state]);
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write_attr(array_states[a->next_state], a->info.state_fd);
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}
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if (a->next_action != bad_action) {
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write_attr(sync_actions[a->next_action], a->action_fd);
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dprintf(" action:%s", array_states[a->next_state]);
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}
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for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
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if (mdi->next_state == DS_REMOVE && mdi->state_fd >= 0) {
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int remove_result;
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write_attr("-blocked", mdi->state_fd);
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/* the kernel may not be able to immediately remove the
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* disk, we can simply wait until the next event to try
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* again.
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*/
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dprintf(" %d:-blocked", mdi->disk.raid_disk);
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remove_result = write_attr("remove", mdi->state_fd);
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if (remove_result > 0) {
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dprintf(" %d:removed", mdi->disk.raid_disk);
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close(mdi->state_fd);
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mdi->state_fd = -1;
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}
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}
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if (mdi->next_state & DS_INSYNC) {
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write_attr("+in_sync", mdi->state_fd);
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dprintf(" %d:+in_sync", mdi->disk.raid_disk);
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}
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}
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dprintf(" )\n");
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/* move curr_ to prev_ */
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a->prev_state = a->curr_state;
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a->prev_action = a->curr_action;
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for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
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mdi->prev_state = mdi->curr_state;
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mdi->next_state = 0;
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}
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if (check_degraded) {
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/* manager will do the actual check */
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a->check_degraded = 1;
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signal_manager();
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}
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if (deactivate)
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a->container = NULL;
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return 1;
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}
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static struct mdinfo *
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find_device(struct active_array *a, int major, int minor)
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{
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struct mdinfo *mdi;
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for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
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if (mdi->disk.major == major && mdi->disk.minor == minor)
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return mdi;
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return NULL;
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}
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static void reconcile_failed(struct active_array *aa, struct mdinfo *failed)
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{
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struct active_array *a;
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struct mdinfo *victim;
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for (a = aa; a; a = a->next) {
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if (!a->container)
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continue;
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victim = find_device(a, failed->disk.major, failed->disk.minor);
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if (!victim)
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continue;
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if (!(victim->curr_state & DS_FAULTY))
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write_attr("faulty", victim->state_fd);
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}
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}
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#ifdef DEBUG
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static void dprint_wake_reasons(fd_set *fds)
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{
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int i;
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char proc_path[256];
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char link[256];
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char *basename;
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int rv;
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fprintf(stderr, "monitor: wake ( ");
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for (i = 0; i < FD_SETSIZE; i++) {
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if (FD_ISSET(i, fds)) {
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sprintf(proc_path, "/proc/%d/fd/%d",
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(int) getpid(), i);
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rv = readlink(proc_path, link, sizeof(link) - 1);
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if (rv < 0) {
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fprintf(stderr, "%d:unknown ", i);
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continue;
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}
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link[rv] = '\0';
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basename = strrchr(link, '/');
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fprintf(stderr, "%d:%s ",
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i, basename ? ++basename : link);
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}
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}
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fprintf(stderr, ")\n");
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}
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#endif
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static int wait_and_act(struct supertype *container, int nowait)
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{
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fd_set rfds;
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int maxfd = 0;
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struct active_array **aap = &container->arrays;
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struct active_array *a, **ap;
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int rv;
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struct mdinfo *mdi;
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FD_ZERO(&rfds);
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for (ap = aap ; *ap ;) {
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a = *ap;
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/* once an array has been deactivated we want to
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* ask the manager to discard it.
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*/
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if (!a->container) {
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if (discard_this) {
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ap = &(*ap)->next;
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continue;
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}
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*ap = a->next;
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a->next = NULL;
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discard_this = a;
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signal_manager();
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continue;
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}
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add_fd(&rfds, &maxfd, a->info.state_fd);
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add_fd(&rfds, &maxfd, a->action_fd);
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for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
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add_fd(&rfds, &maxfd, mdi->state_fd);
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ap = &(*ap)->next;
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}
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if (manager_ready && *aap == NULL) {
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/* No interesting arrays. Lets see about exiting.
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* Note that blocking at this point is not a problem
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* as there are no active arrays, there is nothing that
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* we need to be ready to do.
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*/
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int fd = open(container->device_name, O_RDONLY|O_EXCL);
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if (fd >= 0 || errno != EBUSY) {
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/* OK, we are safe to leave */
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dprintf("no arrays to monitor... exiting\n");
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remove_pidfile(container->devname);
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exit_now = 1;
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signal_manager();
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exit(0);
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}
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}
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if (!nowait) {
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sigset_t set;
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sigprocmask(SIG_UNBLOCK, NULL, &set);
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sigdelset(&set, SIGUSR1);
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rv = pselect(maxfd+1, &rfds, NULL, NULL, NULL, &set);
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if (rv == -1 && errno == EINTR)
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rv = 0;
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#ifdef DEBUG
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dprint_wake_reasons(&rfds);
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#endif
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}
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if (update_queue) {
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struct metadata_update *this;
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for (this = update_queue; this ; this = this->next)
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container->ss->process_update(container, this);
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update_queue_handled = update_queue;
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update_queue = NULL;
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signal_manager();
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container->ss->sync_metadata(container);
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}
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for (a = *aap; a ; a = a->next) {
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if (a->replaces && !discard_this) {
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struct active_array **ap;
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for (ap = &a->next; *ap && *ap != a->replaces;
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ap = & (*ap)->next)
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;
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if (*ap)
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*ap = (*ap)->next;
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discard_this = a->replaces;
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a->replaces = NULL;
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/* FIXME check if device->state_fd need to be cleared?*/
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signal_manager();
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}
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if (a->container)
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rv += read_and_act(a);
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}
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/* propagate failures across container members */
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for (a = *aap; a ; a = a->next) {
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if (!a->container)
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continue;
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for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
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if (mdi->curr_state & DS_FAULTY)
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reconcile_failed(*aap, mdi);
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}
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return rv;
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}
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void do_monitor(struct supertype *container)
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{
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int rv;
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int first = 1;
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do {
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rv = wait_and_act(container, first);
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first = 0;
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} while (rv >= 0);
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}
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