mirror of
git://sourceware.org/git/lvm2.git
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250 lines
6.5 KiB
C
250 lines
6.5 KiB
C
/*
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* Copyright (C) 2007-2015 Red Hat, Inc. All rights reserved.
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*
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* This file is part of LVM2.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU Lesser General Public License v.2.1.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "lib.h"
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#include "dmeventd_lvm.h"
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#include "libdevmapper-event.h"
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#include <sys/wait.h>
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#include <stdarg.h>
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/* First warning when snapshot is 80% full. */
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#define WARNING_THRESH 80
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/* Run a check every 5%. */
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#define CHECK_STEP 5
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/* Do not bother checking snapshots less than 50% full. */
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#define CHECK_MINIMUM 50
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#define UMOUNT_COMMAND "/bin/umount"
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struct dso_state {
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struct dm_pool *mem;
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int percent_check;
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uint64_t known_size;
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char cmd_str[1024];
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};
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DM_EVENT_LOG_FN("snap")
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static int _run(const char *cmd, ...)
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{
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va_list ap;
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int argc = 1; /* for argv[0], i.e. cmd */
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int i = 0;
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const char **argv;
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pid_t pid = fork();
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int status;
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if (pid == 0) { /* child */
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va_start(ap, cmd);
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while (va_arg(ap, const char *))
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++ argc;
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va_end(ap);
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/* + 1 for the terminating NULL */
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argv = alloca(sizeof(const char *) * (argc + 1));
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argv[0] = cmd;
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va_start(ap, cmd);
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while ((argv[++i] = va_arg(ap, const char *)));
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va_end(ap);
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execvp(cmd, (char **)argv);
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log_sys_error("exec", cmd);
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exit(127);
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}
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if (pid > 0) { /* parent */
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if (waitpid(pid, &status, 0) != pid)
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return 0; /* waitpid failed */
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if (!WIFEXITED(status) || WEXITSTATUS(status))
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return 0; /* the child failed */
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}
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if (pid < 0)
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return 0; /* fork failed */
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return 1; /* all good */
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}
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static int _extend(const char *cmd)
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{
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return dmeventd_lvm2_run(cmd);
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}
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static void _umount(const char *device, int major, int minor)
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{
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FILE *mounts;
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char buffer[4096];
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char *words[3];
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struct stat st;
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const char procmounts[] = "/proc/mounts";
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if (!(mounts = fopen(procmounts, "r"))) {
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log_sys_error("fopen", procmounts);
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log_error("Not umounting %s.", device);
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return;
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}
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while (!feof(mounts)) {
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/* read a line of /proc/mounts */
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if (!fgets(buffer, sizeof(buffer), mounts))
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break; /* eof, likely */
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/* words[0] is the mount point and words[1] is the device path */
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if (dm_split_words(buffer, 3, 0, words) < 2)
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continue;
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/* find the major/minor of the device */
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if (stat(words[0], &st))
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continue; /* can't stat, skip this one */
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if (S_ISBLK(st.st_mode) &&
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major(st.st_rdev) == major &&
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minor(st.st_rdev) == minor) {
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log_error("Unmounting invalid snapshot %s from %s.", device, words[1]);
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if (!_run(UMOUNT_COMMAND, "-fl", words[1], NULL))
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log_error("Failed to umount snapshot %s from %s: %s.",
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device, words[1], strerror(errno));
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}
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}
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if (fclose(mounts))
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log_sys_error("close", procmounts);
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}
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void process_event(struct dm_task *dmt,
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enum dm_event_mask event __attribute__((unused)),
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void **user)
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{
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struct dso_state *state = *user;
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void *next = NULL;
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uint64_t start, length;
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char *target_type = NULL;
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char *params;
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struct dm_status_snapshot *status = NULL;
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const char *device = dm_task_get_name(dmt);
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int percent;
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/* No longer monitoring, waiting for remove */
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if (!state->percent_check)
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return;
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dmeventd_lvm2_lock();
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dm_get_next_target(dmt, next, &start, &length, &target_type, ¶ms);
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if (!target_type)
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goto out;
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if (!dm_get_status_snapshot(state->mem, params, &status))
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goto out;
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if (status->invalid || status->overflow) {
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struct dm_info info;
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log_error("Snapshot %s is lost.", device);
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if (dm_task_get_info(dmt, &info)) {
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dmeventd_lvm2_unlock();
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_umount(device, info.major, info.minor);
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return;
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} /* else; too bad, but this is best-effort thing... */
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}
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/* Snapshot size had changed. Clear the threshold. */
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if (state->known_size != status->total_sectors) {
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state->percent_check = CHECK_MINIMUM;
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state->known_size = status->total_sectors;
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}
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/*
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* If the snapshot has been invalidated or we failed to parse
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* the status string. Report the full status string to syslog.
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*/
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if (status->invalid || status->overflow || !status->total_sectors) {
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log_error("Snapshot %s changed state to: %s.", device, params);
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state->percent_check = 0;
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goto out;
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}
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percent = (int) (100 * status->used_sectors / status->total_sectors);
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if (percent >= state->percent_check) {
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/* Usage has raised more than CHECK_STEP since the last
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time. Run actions. */
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state->percent_check = (percent / CHECK_STEP) * CHECK_STEP + CHECK_STEP;
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if (percent >= WARNING_THRESH) /* Print a warning to syslog. */
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log_warn("WARNING: Snapshot %s is now %i%% full.", device, percent);
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/* Try to extend the snapshot, in accord with user-set policies */
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if (!_extend(state->cmd_str))
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log_error("Failed to extend snapshot %s.", device);
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}
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out:
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if (status)
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dm_pool_free(state->mem, status);
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dmeventd_lvm2_unlock();
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}
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int register_device(const char *device,
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const char *uuid __attribute__((unused)),
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int major __attribute__((unused)),
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int minor __attribute__((unused)),
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void **user)
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{
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struct dm_pool *statemem = NULL;
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struct dso_state *state;
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if (!dmeventd_lvm2_init())
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goto out;
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if (!(statemem = dm_pool_create("snapshot_state", 512)) ||
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!(state = dm_pool_zalloc(statemem, sizeof(*state))))
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goto bad;
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if (!dmeventd_lvm2_command(statemem, state->cmd_str,
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sizeof(state->cmd_str),
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"lvextend --use-policies", device))
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goto bad;
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state->mem = statemem;
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state->percent_check = CHECK_MINIMUM;
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*user = state;
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log_info("Monitoring snapshot %s.", device);
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return 1;
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bad:
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if (statemem)
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dm_pool_destroy(statemem);
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dmeventd_lvm2_exit();
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out:
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log_error("Failed to monitor snapshot %s.", device);
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return 0;
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}
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int unregister_device(const char *device,
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const char *uuid __attribute__((unused)),
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int major __attribute__((unused)),
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int minor __attribute__((unused)),
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void **user)
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{
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struct dso_state *state = *user;
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log_info("No longer monitoring snapshot %s.", device);
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dm_pool_destroy(state->mem);
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dmeventd_lvm2_exit();
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return 1;
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}
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