tools/polldaemon.c - platform/external/lvm2 - Git at Google

 /*
  * Copyright (C) 2003-2004 Sistina Software, Inc. All rights reserved.
  * Copyright (C) 2004-2015 Red Hat, Inc. All rights reserved.
  *
  * This file is part of LVM2.
  *
  * This copyrighted material is made available to anyone wishing to use,
  * modify, copy, or redistribute it subject to the terms and conditions
  * of the GNU Lesser General Public License v.2.1.
  *
  * You should have received a copy of the GNU Lesser General Public License
  * along with this program; if not, write to the Free Software Foundation,
  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */

 #include "tools.h"

 #include "polldaemon.h"
 #include "lvm2cmdline.h"
 #include "lvmpolld-client.h"

 #include <time.h>

 #define WAIT_AT_LEAST_NANOSECS 100000

 progress_t poll_mirror_progress(struct cmd_context *cmd,
 				struct logical_volume *lv, const char *name,
 				struct daemon_parms *parms)
 {
 	dm_percent_t segment_percent = DM_PERCENT_0, overall_percent = DM_PERCENT_0;
 	uint32_t event_nr = 0;

 	if (!lv_is_mirrored(lv) ||
 	    !lv_mirror_percent(cmd, lv, !parms->interval, &segment_percent,
 			       &event_nr) ||
 	    (segment_percent == DM_PERCENT_INVALID)) {
 		log_error("ABORTING: Mirror percentage check failed.");
 		return PROGRESS_CHECK_FAILED;
 	}

 	overall_percent = copy_percent(lv);
 	if (parms->progress_display)
 		log_print_unless_silent("%s: %s: %.1f%%", name, parms->progress_title,
 					dm_percent_to_float(overall_percent));
 	else
 		log_verbose("%s: %s: %.1f%%", name, parms->progress_title,
 			    dm_percent_to_float(overall_percent));

 	if (segment_percent != DM_PERCENT_100)
 		return PROGRESS_UNFINISHED;

 	if (overall_percent == DM_PERCENT_100)
 		return PROGRESS_FINISHED_ALL;

 	return PROGRESS_FINISHED_SEGMENT;
 }

 static int _check_lv_status(struct cmd_context *cmd,
 			    struct volume_group *vg,
 			    struct logical_volume *lv,
 			    const char *name, struct daemon_parms *parms,
 			    int *finished)
 {
 	struct dm_list *lvs_changed;
 	progress_t progress;

 	/* By default, caller should not retry */
 	*finished = 1;

 	if (parms->aborting) {
 		if (!(lvs_changed = lvs_using_lv(cmd, vg, lv))) {
 			log_error("Failed to generate list of copied LVs: "
 				  "can't abort.");
 			return 0;
 		}
 		if (!parms->poll_fns->finish_copy(cmd, vg, lv, lvs_changed))
 			return_0;

 		return 1;
 	}

 	progress = parms->poll_fns->poll_progress(cmd, lv, name, parms);
 	if (progress == PROGRESS_CHECK_FAILED)
 		return_0;

 	if (progress == PROGRESS_UNFINISHED) {
 		/* The only case the caller *should* try again later */
 		*finished = 0;
 		return 1;
 	}

 	if (!(lvs_changed = lvs_using_lv(cmd, vg, lv))) {
 		log_error("ABORTING: Failed to generate list of copied LVs");
 		return 0;
 	}

 	/* Finished? Or progress to next segment? */
 	if (progress == PROGRESS_FINISHED_ALL) {
 		if (!parms->poll_fns->finish_copy(cmd, vg, lv, lvs_changed))
 			return_0;
 	} else {
 		if (parms->poll_fns->update_metadata &&
 		    !parms->poll_fns->update_metadata(cmd, vg, lv, lvs_changed, 0)) {
 			log_error("ABORTING: Segment progression failed.");
 			parms->poll_fns->finish_copy(cmd, vg, lv, lvs_changed);
 			return 0;
 		}
 		*finished = 0;	/* Another segment */
 	}

 	return 1;
 }

 static void _nanosleep(unsigned secs, unsigned allow_zero_time)
 {
 	struct timespec wtime = {
 		.tv_sec = secs,
 	};

 	if (!secs && !allow_zero_time)
 		wtime.tv_nsec = WAIT_AT_LEAST_NANOSECS;

 	while (!nanosleep(&wtime, &wtime) && errno == EINTR) {}
 }

 static void _sleep_and_rescan_devices(struct daemon_parms *parms)
 {
 	if (parms->interval && !parms->aborting) {
 		dev_close_all();
 		_nanosleep(parms->interval, 1);
 		/* Devices might have changed while we slept */
 		init_full_scan_done(0);
 	}
 }

 int wait_for_single_lv(struct cmd_context *cmd, struct poll_operation_id *id,
 		       struct daemon_parms *parms)
 {
 	struct volume_group *vg = NULL;
 	struct logical_volume *lv;
 	int finished = 0;
 	uint32_t lockd_state = 0;
 	int ret;

 	/* Poll for completion */
 	while (!finished) {
 		if (parms->wait_before_testing)
 			_sleep_and_rescan_devices(parms);

 		/*
 		 * An ex VG lock is needed because the check can call finish_copy
 		 * which writes the VG.
 		 */
 		if (!lockd_vg(cmd, id->vg_name, "ex", 0, &lockd_state)) {
 			log_error("ABORTING: Can't lock VG for %s.", id->display_name);
 			return 0;
 		}

 		/* Locks the (possibly renamed) VG again */
 		vg = vg_read(cmd, id->vg_name, NULL, READ_FOR_UPDATE, lockd_state);
 		if (vg_read_error(vg)) {
 			/* What more could we do here? */
 			log_error("ABORTING: Can't reread VG for %s.", id->display_name);
 			release_vg(vg);
 			vg = NULL;
 			ret = 0;
 			goto out;
 		}

 		lv = find_lv(vg, id->lv_name);

 		if (lv && id->uuid && strcmp(id->uuid, (char *)&lv->lvid))
 			lv = NULL;
 		if (lv && parms->lv_type && !(lv->status & parms->lv_type))
 			lv = NULL;

 		if (!lv) {
 			if (parms->lv_type == PVMOVE)
 				log_print_unless_silent("%s: No pvmove in progress - already finished or aborted.",
 							id->display_name);
 			else
 				log_print_unless_silent("Can't find LV in %s for %s.",
 							vg->name, id->display_name);
 			ret = 1;
 			goto out;
 		}

 		/*
 		 * If the LV is not active locally, the kernel cannot be
 		 * queried for its status.  We must exit in this case.
 		 */
 		if (!lv_is_active_locally(lv)) {
 			log_print_unless_silent("%s: Interrupted: No longer active.", id->display_name);
 			ret = 1;
 			goto out;
 		}

 		if (!_check_lv_status(cmd, vg, lv, id->display_name, parms, &finished)) {
 			ret = 0;
 			goto_out;
 		}

 		unlock_and_release_vg(cmd, vg, vg->name);

 		if (!lockd_vg(cmd, id->vg_name, "un", 0, &lockd_state))
 			stack;

 		/*
 		 * FIXME Sleeping after testing, while preferred, also works around
 		 * unreliable "finished" state checking in _percent_run.  If the
 		 * above _check_lv_status is deferred until after the first sleep it
 		 * may be that a polldaemon will run without ever completing.
 		 *
 		 * This happens when one snapshot-merge polldaemon is racing with
 		 * another (polling the same LV).  The first to see the LV status
 		 * reach the "finished" state will alter the LV that the other
 		 * polldaemon(s) are polling.  These other polldaemon(s) can then
 		 * continue polling an LV that doesn't have a "status".
 		 */
 		if (!parms->wait_before_testing && !finished)
 			_sleep_and_rescan_devices(parms);
 	}

 	return 1;

 out:
 	if (vg)
 		unlock_and_release_vg(cmd, vg, vg->name);
 	if (!lockd_vg(cmd, id->vg_name, "un", 0, &lockd_state))
 		stack;

 	return ret;
 }

 struct poll_id_list {
 	struct dm_list list;
 	struct poll_operation_id *id;
 };

 static struct poll_operation_id *copy_poll_operation_id(struct dm_pool *mem,
 							const struct poll_operation_id *id)
 {
 	struct poll_operation_id *copy;

 	if (!id)
 		return_NULL;

 	copy = (struct poll_operation_id *) dm_pool_alloc(mem, sizeof(struct poll_operation_id));
 	if (!copy) {
 		log_error("Poll operation ID allocation failed.");
 		return NULL;
 	}

 	copy->display_name = id->display_name ? dm_pool_strdup(mem, id->display_name) : NULL;
 	copy->lv_name = id->lv_name ? dm_pool_strdup(mem, id->lv_name) : NULL;
 	copy->vg_name = id->vg_name ? dm_pool_strdup(mem, id->vg_name) : NULL;
 	copy->uuid = id->uuid ? dm_pool_strdup(mem, id->uuid) : NULL;

 	if (!copy->display_name || !copy->lv_name || !copy->vg_name || !copy->uuid) {
 		log_error("Failed to copy one or more poll_operation_id members.");
 		return NULL;
 	}

 	return copy;
 }

 static struct poll_id_list* poll_id_list_create(struct dm_pool *mem,
 						const struct poll_operation_id *id)
 {
 	struct poll_id_list *idl = (struct poll_id_list *) dm_pool_alloc(mem, sizeof(struct poll_id_list));

 	if (!idl) {
 		log_error("Poll ID list allocation failed.");
 		return NULL;
 	}

 	if (!(idl->id = copy_poll_operation_id(mem, id))) {
 		dm_pool_free(mem, idl);
 		return NULL;
 	}

 	return idl;
 }

 static int _poll_vg(struct cmd_context *cmd, const char *vgname,
 		    struct volume_group *vg, struct processing_handle *handle)
 {
 	struct daemon_parms *parms;
 	struct lv_list *lvl;
 	struct dm_list idls;
 	struct poll_id_list *idl;
 	struct poll_operation_id id;
 	struct logical_volume *lv;
 	int finished;

 	if (!handle || !(parms = (struct daemon_parms *) handle->custom_handle)) {
 		log_error(INTERNAL_ERROR "Handle is undefined.");
 		return ECMD_FAILED;
 	}

 	dm_list_init(&idls);

 	/*
 	 * first iterate all LVs in a VG and collect LVs suitable
 	 * for polling (or an abort) which takes place below
 	 */
 	dm_list_iterate_items(lvl, &vg->lvs) {
 		lv = lvl->lv;
 		if (!(lv->status & parms->lv_type))
 			continue;
 		id.display_name = parms->poll_fns->get_copy_name_from_lv(lv);
 		if (!id.display_name && !parms->aborting)
 			continue;

 		if (!id.display_name) {
 			log_error("Device name for LV %s not found in metadata. "
 				  "(unfinished pvmove mirror removal?)", display_lvname(lv));
 			goto err;
 		}

 		/* FIXME Need to do the activation from _set_up_pvmove here
 		 *       if it's not running and we're not aborting. */
 		if (!lv_is_active(lv)) {
 			log_print_unless_silent("%s: Skipping inactive LV. Try lvchange or vgchange.", id.display_name);
 			continue;
 		}

 		id.lv_name = lv->name;
 		id.vg_name = vg->name;
 		id.uuid = lv->lvid.s;

 		idl = poll_id_list_create(cmd->mem, &id);
 		if (!idl) {
 			log_error("Failed to create poll_id_list.");
 			goto err;
 		}

 		dm_list_add(&idls, &idl->list);
 	}

 	/* perform the poll operation on LVs collected in previous cycle */
 	dm_list_iterate_items(idl, &idls) {
 		if (!(lv = find_lv(vg, idl->id->lv_name)))
 			continue;
 		if (idl->id->uuid && strcmp(idl->id->uuid, (char *)&lv->lvid))
 			continue;
 		if (parms->lv_type && !(lv->status & parms->lv_type))
 			continue;
 		if (_check_lv_status(cmd, vg, lv, idl->id->display_name, parms, &finished) && !finished)
 			parms->outstanding_count++;
 	}

 err:
 	if (!dm_list_empty(&idls))
 		dm_pool_free(cmd->mem, dm_list_item(dm_list_first(&idls), struct poll_id_list));

 	return ECMD_PROCESSED;
 }

 static void _poll_for_all_vgs(struct cmd_context *cmd,
 			      struct processing_handle *handle)
 {
 	struct daemon_parms *parms = (struct daemon_parms *) handle->custom_handle;

 	while (1) {
 		parms->outstanding_count = 0;
 		process_each_vg(cmd, 0, NULL, READ_FOR_UPDATE, handle, _poll_vg);
 		if (!parms->outstanding_count)
 			break;
 		if (parms->interval)
 			dev_close_all();
 		_nanosleep(parms->interval, 1);
 	}
 }

 #ifdef LVMPOLLD_SUPPORT
 typedef struct {
 	struct daemon_parms *parms;
 	struct dm_list idls;
 } lvmpolld_parms_t;

 static int report_progress(struct cmd_context *cmd, struct poll_operation_id *id,
 			   struct daemon_parms *parms)
 {
 	struct volume_group *vg;
 	struct logical_volume *lv;
 	uint32_t lockd_state = 0;
 	int ret;

 	/*
 	 * It's reasonable to expect a lockd_vg("sh") here, but it should
 	 * not actually be needed, because we only report the progress on
 	 * the same host where the pvmove/lvconvert is happening.  This means
 	 * that the local pvmove/lvconvert/lvpoll commands are updating the
 	 * local lvmetad with the latest info they have, and we just need to
 	 * read the latest info that they have put into lvmetad about their
 	 * progress.  No VG lock is needed to protect anything here (we're
 	 * just reading the VG), and no VG lock is needed to force a VG read
 	 * from disk to get changes from other hosts, because the only change
 	 * to the VG we're interested in is the change done locally.
 	 */

 	vg = vg_read(cmd, id->vg_name, NULL, 0, lockd_state);
 	if (vg_read_error(vg)) {
 		release_vg(vg);
 		log_error("Can't reread VG for %s", id->display_name);
 		ret = 0;
 		goto out_ret;
 	}

 	lv = find_lv(vg, id->lv_name);

 	if (lv && id->uuid && strcmp(id->uuid, (char *)&lv->lvid))
 		lv = NULL;
 	if (lv && parms->lv_type && !(lv->status & parms->lv_type))
 		lv = NULL;

 	if (!lv) {
 		if (parms->lv_type == PVMOVE)
 			log_verbose("%s: No pvmove in progress - already finished or aborted.",
 				    id->display_name);
 		else
 			log_verbose("Can't find LV in %s for %s. Already finished or removed.",
 				    vg->name, id->display_name);
 		ret = 1;
 		goto out;
 	}

 	if (!lv_is_active_locally(lv)) {
 		log_verbose("%s: Interrupted: No longer active.", id->display_name);
 		ret = 1;
 		goto out;
 	}

 	if (parms->poll_fns->poll_progress(cmd, lv, id->display_name, parms) == PROGRESS_CHECK_FAILED) {
 		ret = 0;
 		goto out;
 	}

 	ret = 1;

 out:
 	unlock_and_release_vg(cmd, vg, vg->name);
 out_ret:
 	return ret;
 }

 static int _lvmpolld_init_poll_vg(struct cmd_context *cmd, const char *vgname,
 			          struct volume_group *vg, struct processing_handle *handle)
 {
 	int r;
 	struct lv_list *lvl;
 	struct logical_volume *lv;
 	struct poll_id_list *idl;
 	struct poll_operation_id id;
 	lvmpolld_parms_t *lpdp = (lvmpolld_parms_t *) handle->custom_handle;

 	dm_list_iterate_items(lvl, &vg->lvs) {
 		lv = lvl->lv;
 		if (!(lv->status & lpdp->parms->lv_type))
 			continue;

 		id.display_name = lpdp->parms->poll_fns->get_copy_name_from_lv(lv);
 		if (!id.display_name && !lpdp->parms->aborting)
 			continue;

 		id.vg_name = lv->vg->name;
 		id.lv_name = lv->name;

 		if (!*lv->lvid.s) {
 			log_print_unless_silent("Missing LV uuid within: %s/%s", id.vg_name, id.lv_name);
 			continue;
 		}

 		id.uuid = lv->lvid.s;

 		r = lvmpolld_poll_init(cmd, &id, lpdp->parms);

 		if (r && !lpdp->parms->background) {
 			if (!(idl = poll_id_list_create(cmd->mem, &id)))
 				return ECMD_FAILED;

 			dm_list_add(&lpdp->idls, &idl->list);
 		}
 	}

 	return ECMD_PROCESSED;
 }

 static void _lvmpolld_poll_for_all_vgs(struct cmd_context *cmd,
 				       struct daemon_parms *parms,
 				       struct processing_handle *handle)
 {
 	int r;
 	struct dm_list *first;
 	struct poll_id_list *idl, *tlv;
 	unsigned finished;
 	lvmpolld_parms_t lpdp = {
 		.parms = parms
 	};

 	dm_list_init(&lpdp.idls);

 	handle->custom_handle = &lpdp;

 	process_each_vg(cmd, 0, NULL, 0, handle, _lvmpolld_init_poll_vg);

 	first = dm_list_first(&lpdp.idls);

 	while (!dm_list_empty(&lpdp.idls)) {
 		dm_list_iterate_items_safe(idl, tlv, &lpdp.idls) {
 			r = lvmpolld_request_info(idl->id, lpdp.parms,
 						  &finished);
 			if (!r || finished)
 				dm_list_del(&idl->list);
 			else if (!parms->aborting)
 				report_progress(cmd, idl->id, lpdp.parms);
 		}

 		if (lpdp.parms->interval)
 			dev_close_all();

 		_nanosleep(lpdp.parms->interval, 0);
 	}

 	if (first)
 		dm_pool_free(cmd->mem, dm_list_item(first, struct poll_id_list));
 }

 static int _lvmpoll_daemon(struct cmd_context *cmd, struct poll_operation_id *id,
 			   struct daemon_parms *parms)
 {
 	int r;
 	struct processing_handle *handle = NULL;
 	unsigned finished = 0;

 	if (parms->aborting)
 		parms->interval = 0;

 	if (id) {
 		r = lvmpolld_poll_init(cmd, id, parms);
 		if (r && !parms->background) {
 			while (1) {
 				if (!(r = lvmpolld_request_info(id, parms, &finished)) ||
 				    finished ||
 				    (!parms->aborting && !(r = report_progress(cmd, id, parms))))
 					break;

 				if (parms->interval)
 					dev_close_all();

 				_nanosleep(parms->interval, 0);
 			}
 		}

 		return r ? ECMD_PROCESSED : ECMD_FAILED;
 	} else {
 		/* process all in-flight operations */
 		if (!(handle = init_processing_handle(cmd))) {
 			log_error("Failed to initialize processing handle.");
 			return ECMD_FAILED;
 		} else {
 			_lvmpolld_poll_for_all_vgs(cmd, parms, handle);
 			destroy_processing_handle(cmd, handle);
 			return ECMD_PROCESSED;
 		}
 	}
 }
 #else
 #	define _lvmpoll_daemon(cmd, id, parms) (ECMD_FAILED)
 #endif /* LVMPOLLD_SUPPORT */

 /*
  * Only allow *one* return from poll_daemon() (the parent).
  * If there is a child it must exit (ignoring the memory leak messages).
  * - 'background' is advisory so a child polldaemon may not be used even
  *   if it was requested.
  */
 static int _poll_daemon(struct cmd_context *cmd, struct poll_operation_id *id,
 			struct daemon_parms *parms)
 {
 	struct processing_handle *handle = NULL;
 	int daemon_mode = 0;
 	int ret = ECMD_PROCESSED;

 	if (parms->background) {
 		daemon_mode = become_daemon(cmd, 0);
 		if (daemon_mode == 0)
 			return ECMD_PROCESSED;	    /* Parent */
 		else if (daemon_mode == 1)
 			parms->progress_display = 0; /* Child */
 		/* FIXME Use wait_event (i.e. interval = 0) and */
 		/*       fork one daemon per copy? */
 	}

 	/*
 	 * Process one specific task or all incomplete tasks?
 	 */
 	if (id) {
 		if (!wait_for_single_lv(cmd, id, parms)) {
 			stack;
 			ret = ECMD_FAILED;
 		}
 	} else {
 		if (!parms->interval)
 			parms->interval = find_config_tree_int(cmd, activation_polling_interval_CFG, NULL);
 		if (!(handle = init_processing_handle(cmd))) {
 			log_error("Failed to initialize processing handle.");
 			ret = ECMD_FAILED;
 		} else {
 			handle->custom_handle = parms;
 			_poll_for_all_vgs(cmd, handle);
 		}
 	}

 	if (parms->background && daemon_mode == 1) {
 		destroy_processing_handle(cmd, handle);
 		/*
 		 * child was successfully forked:
 		 * background polldaemon must not return to the caller
 		 * because it will redundantly continue performing the
 		 * caller's task (that the parent already performed)
 		 */
 		/* FIXME Attempt proper cleanup */
 		_exit(lvm_return_code(ret));
 	}

 	destroy_processing_handle(cmd, handle);
 	return ret;
 }

 static int _daemon_parms_init(struct cmd_context *cmd, struct daemon_parms *parms,
 			      unsigned background, struct poll_functions *poll_fns,
 			      const char *progress_title, uint64_t lv_type)
 {
 	sign_t interval_sign;

 	parms->aborting = arg_is_set(cmd, abort_ARG);
 	parms->background = background;
 	interval_sign = arg_sign_value(cmd, interval_ARG, SIGN_NONE);
 	if (interval_sign == SIGN_MINUS) {
 		log_error("Argument to --interval cannot be negative.");
 		return 0;
 	}
 	parms->interval = arg_uint_value(cmd, interval_ARG,
 					 find_config_tree_int(cmd, activation_polling_interval_CFG, NULL));
 	parms->wait_before_testing = (interval_sign == SIGN_PLUS);
 	parms->progress_title = progress_title;
 	parms->lv_type = lv_type;
 	parms->poll_fns = poll_fns;

 	if (parms->interval && !parms->aborting)
 		log_verbose("Checking progress %s waiting every %u seconds.",
 			    (parms->wait_before_testing ? "after" : "before"),
 			    parms->interval);

 	parms->progress_display = parms->interval ? 1 : 0;

 	return 1;
 }

 int poll_daemon(struct cmd_context *cmd, unsigned background,
 		uint64_t lv_type, struct poll_functions *poll_fns,
 		const char *progress_title, struct poll_operation_id *id)
 {
 	struct daemon_parms parms;

 	if (!_daemon_parms_init(cmd, &parms, background, poll_fns, progress_title, lv_type))
 		return_EINVALID_CMD_LINE;

 	if (lvmpolld_use())
 		return _lvmpoll_daemon(cmd, id, &parms);
 	else {
 		/* classical polling allows only PMVOVE or 0 values */
 		parms.lv_type &= PVMOVE;
 		return _poll_daemon(cmd, id, &parms);
 	}
 }
	/*
	* Copyright (C) 2003-2004 Sistina Software, Inc. All rights reserved.
	* Copyright (C) 2004-2015 Red Hat, Inc. All rights reserved.
	*
	* This file is part of LVM2.
	*
	* This copyrighted material is made available to anyone wishing to use,
	* modify, copy, or redistribute it subject to the terms and conditions
	* of the GNU Lesser General Public License v.2.1.
	*
	* You should have received a copy of the GNU Lesser General Public License
	* along with this program; if not, write to the Free Software Foundation,
	* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#include "tools.h"

	#include "polldaemon.h"
	#include "lvm2cmdline.h"
	#include "lvmpolld-client.h"

	#include <time.h>

	#define WAIT_AT_LEAST_NANOSECS 100000

	progress_t poll_mirror_progress(struct cmd_context *cmd,
	struct logical_volume lv, const char name,
	struct daemon_parms *parms)
	{
	dm_percent_t segment_percent = DM_PERCENT_0, overall_percent = DM_PERCENT_0;
	uint32_t event_nr = 0;

	if (!lv_is_mirrored(lv) \|\|
	!lv_mirror_percent(cmd, lv, !parms->interval, &segment_percent,
	&event_nr) \|\|
	(segment_percent == DM_PERCENT_INVALID)) {
	log_error("ABORTING: Mirror percentage check failed.");
	return PROGRESS_CHECK_FAILED;
	}

	overall_percent = copy_percent(lv);
	if (parms->progress_display)
	log_print_unless_silent("%s: %s: %.1f%%", name, parms->progress_title,
	dm_percent_to_float(overall_percent));
	else
	log_verbose("%s: %s: %.1f%%", name, parms->progress_title,
	dm_percent_to_float(overall_percent));

	if (segment_percent != DM_PERCENT_100)
	return PROGRESS_UNFINISHED;

	if (overall_percent == DM_PERCENT_100)
	return PROGRESS_FINISHED_ALL;

	return PROGRESS_FINISHED_SEGMENT;
	}

	static int _check_lv_status(struct cmd_context *cmd,
	struct volume_group *vg,
	struct logical_volume *lv,
	const char name, struct daemon_parms parms,
	int *finished)
	{
	struct dm_list *lvs_changed;
	progress_t progress;

	/* By default, caller should not retry */
	*finished = 1;

	if (parms->aborting) {
	if (!(lvs_changed = lvs_using_lv(cmd, vg, lv))) {
	log_error("Failed to generate list of copied LVs: "
	"can't abort.");
	return 0;
	}
	if (!parms->poll_fns->finish_copy(cmd, vg, lv, lvs_changed))
	return_0;

	return 1;
	}

	progress = parms->poll_fns->poll_progress(cmd, lv, name, parms);
	if (progress == PROGRESS_CHECK_FAILED)
	return_0;

	if (progress == PROGRESS_UNFINISHED) {
	/* The only case the caller should try again later */
	*finished = 0;
	return 1;
	}

	if (!(lvs_changed = lvs_using_lv(cmd, vg, lv))) {
	log_error("ABORTING: Failed to generate list of copied LVs");
	return 0;
	}

	/* Finished? Or progress to next segment? */
	if (progress == PROGRESS_FINISHED_ALL) {
	if (!parms->poll_fns->finish_copy(cmd, vg, lv, lvs_changed))
	return_0;
	} else {
	if (parms->poll_fns->update_metadata &&
	!parms->poll_fns->update_metadata(cmd, vg, lv, lvs_changed, 0)) {
	log_error("ABORTING: Segment progression failed.");
	parms->poll_fns->finish_copy(cmd, vg, lv, lvs_changed);
	return 0;
	}
	finished = 0; / Another segment */
	}

	return 1;
	}

	static void _nanosleep(unsigned secs, unsigned allow_zero_time)
	{
	struct timespec wtime = {
	.tv_sec = secs,
	};

	if (!secs && !allow_zero_time)
	wtime.tv_nsec = WAIT_AT_LEAST_NANOSECS;

	while (!nanosleep(&wtime, &wtime) && errno == EINTR) {}
	}

	static void _sleep_and_rescan_devices(struct daemon_parms *parms)
	{
	if (parms->interval && !parms->aborting) {
	dev_close_all();
	_nanosleep(parms->interval, 1);
	/* Devices might have changed while we slept */
	init_full_scan_done(0);
	}
	}

	int wait_for_single_lv(struct cmd_context cmd, struct poll_operation_id id,
	struct daemon_parms *parms)
	{
	struct volume_group *vg = NULL;
	struct logical_volume *lv;
	int finished = 0;
	uint32_t lockd_state = 0;
	int ret;

	/* Poll for completion */
	while (!finished) {
	if (parms->wait_before_testing)
	_sleep_and_rescan_devices(parms);

	/*
	* An ex VG lock is needed because the check can call finish_copy
	* which writes the VG.
	*/
	if (!lockd_vg(cmd, id->vg_name, "ex", 0, &lockd_state)) {
	log_error("ABORTING: Can't lock VG for %s.", id->display_name);
	return 0;
	}

	/* Locks the (possibly renamed) VG again */
	vg = vg_read(cmd, id->vg_name, NULL, READ_FOR_UPDATE, lockd_state);
	if (vg_read_error(vg)) {
	/* What more could we do here? */
	log_error("ABORTING: Can't reread VG for %s.", id->display_name);
	release_vg(vg);
	vg = NULL;
	ret = 0;
	goto out;
	}

	lv = find_lv(vg, id->lv_name);

	if (lv && id->uuid && strcmp(id->uuid, (char *)&lv->lvid))
	lv = NULL;
	if (lv && parms->lv_type && !(lv->status & parms->lv_type))
	lv = NULL;

	if (!lv) {
	if (parms->lv_type == PVMOVE)
	log_print_unless_silent("%s: No pvmove in progress - already finished or aborted.",
	id->display_name);
	else
	log_print_unless_silent("Can't find LV in %s for %s.",
	vg->name, id->display_name);
	ret = 1;
	goto out;
	}

	/*
	* If the LV is not active locally, the kernel cannot be
	* queried for its status. We must exit in this case.
	*/
	if (!lv_is_active_locally(lv)) {
	log_print_unless_silent("%s: Interrupted: No longer active.", id->display_name);
	ret = 1;
	goto out;
	}

	if (!_check_lv_status(cmd, vg, lv, id->display_name, parms, &finished)) {
	ret = 0;
	goto_out;
	}

	unlock_and_release_vg(cmd, vg, vg->name);

	if (!lockd_vg(cmd, id->vg_name, "un", 0, &lockd_state))
	stack;

	/*
	* FIXME Sleeping after testing, while preferred, also works around
	* unreliable "finished" state checking in _percent_run. If the
	* above _check_lv_status is deferred until after the first sleep it
	* may be that a polldaemon will run without ever completing.
	*
	* This happens when one snapshot-merge polldaemon is racing with
	* another (polling the same LV). The first to see the LV status
	* reach the "finished" state will alter the LV that the other
	* polldaemon(s) are polling. These other polldaemon(s) can then
	* continue polling an LV that doesn't have a "status".
	*/
	if (!parms->wait_before_testing && !finished)
	_sleep_and_rescan_devices(parms);
	}

	return 1;

	out:
	if (vg)
	unlock_and_release_vg(cmd, vg, vg->name);
	if (!lockd_vg(cmd, id->vg_name, "un", 0, &lockd_state))
	stack;

	return ret;
	}

	struct poll_id_list {
	struct dm_list list;
	struct poll_operation_id *id;
	};

	static struct poll_operation_id copy_poll_operation_id(struct dm_pool mem,
	const struct poll_operation_id *id)
	{
	struct poll_operation_id *copy;

	if (!id)
	return_NULL;

	copy = (struct poll_operation_id *) dm_pool_alloc(mem, sizeof(struct poll_operation_id));
	if (!copy) {
	log_error("Poll operation ID allocation failed.");
	return NULL;
	}

	copy->display_name = id->display_name ? dm_pool_strdup(mem, id->display_name) : NULL;
	copy->lv_name = id->lv_name ? dm_pool_strdup(mem, id->lv_name) : NULL;
	copy->vg_name = id->vg_name ? dm_pool_strdup(mem, id->vg_name) : NULL;
	copy->uuid = id->uuid ? dm_pool_strdup(mem, id->uuid) : NULL;

	if (!copy->display_name \|\| !copy->lv_name \|\| !copy->vg_name \|\| !copy->uuid) {
	log_error("Failed to copy one or more poll_operation_id members.");
	return NULL;
	}

	return copy;
	}

	static struct poll_id_list* poll_id_list_create(struct dm_pool *mem,
	const struct poll_operation_id *id)
	{
	struct poll_id_list idl = (struct poll_id_list ) dm_pool_alloc(mem, sizeof(struct poll_id_list));

	if (!idl) {
	log_error("Poll ID list allocation failed.");
	return NULL;
	}

	if (!(idl->id = copy_poll_operation_id(mem, id))) {
	dm_pool_free(mem, idl);
	return NULL;
	}

	return idl;
	}

	static int _poll_vg(struct cmd_context cmd, const char vgname,
	struct volume_group vg, struct processing_handle handle)
	{
	struct daemon_parms *parms;
	struct lv_list *lvl;
	struct dm_list idls;
	struct poll_id_list *idl;
	struct poll_operation_id id;
	struct logical_volume *lv;
	int finished;

	if (!handle \|\| !(parms = (struct daemon_parms *) handle->custom_handle)) {
	log_error(INTERNAL_ERROR "Handle is undefined.");
	return ECMD_FAILED;
	}

	dm_list_init(&idls);

	/*
	* first iterate all LVs in a VG and collect LVs suitable
	* for polling (or an abort) which takes place below
	*/
	dm_list_iterate_items(lvl, &vg->lvs) {
	lv = lvl->lv;
	if (!(lv->status & parms->lv_type))
	continue;
	id.display_name = parms->poll_fns->get_copy_name_from_lv(lv);
	if (!id.display_name && !parms->aborting)
	continue;

	if (!id.display_name) {
	log_error("Device name for LV %s not found in metadata. "
	"(unfinished pvmove mirror removal?)", display_lvname(lv));
	goto err;
	}

	/* FIXME Need to do the activation from _set_up_pvmove here
	* if it's not running and we're not aborting. */
	if (!lv_is_active(lv)) {
	log_print_unless_silent("%s: Skipping inactive LV. Try lvchange or vgchange.", id.display_name);
	continue;
	}

	id.lv_name = lv->name;
	id.vg_name = vg->name;
	id.uuid = lv->lvid.s;

	idl = poll_id_list_create(cmd->mem, &id);
	if (!idl) {
	log_error("Failed to create poll_id_list.");
	goto err;
	}

	dm_list_add(&idls, &idl->list);
	}

	/* perform the poll operation on LVs collected in previous cycle */
	dm_list_iterate_items(idl, &idls) {
	if (!(lv = find_lv(vg, idl->id->lv_name)))
	continue;
	if (idl->id->uuid && strcmp(idl->id->uuid, (char *)&lv->lvid))
	continue;
	if (parms->lv_type && !(lv->status & parms->lv_type))
	continue;
	if (_check_lv_status(cmd, vg, lv, idl->id->display_name, parms, &finished) && !finished)
	parms->outstanding_count++;
	}

	err:
	if (!dm_list_empty(&idls))
	dm_pool_free(cmd->mem, dm_list_item(dm_list_first(&idls), struct poll_id_list));

	return ECMD_PROCESSED;
	}

	static void _poll_for_all_vgs(struct cmd_context *cmd,
	struct processing_handle *handle)
	{
	struct daemon_parms parms = (struct daemon_parms ) handle->custom_handle;

	while (1) {
	parms->outstanding_count = 0;
	process_each_vg(cmd, 0, NULL, READ_FOR_UPDATE, handle, _poll_vg);
	if (!parms->outstanding_count)
	break;
	if (parms->interval)
	dev_close_all();
	_nanosleep(parms->interval, 1);
	}
	}

	#ifdef LVMPOLLD_SUPPORT
	typedef struct {
	struct daemon_parms *parms;
	struct dm_list idls;
	} lvmpolld_parms_t;

	static int report_progress(struct cmd_context cmd, struct poll_operation_id id,
	struct daemon_parms *parms)
	{
	struct volume_group *vg;
	struct logical_volume *lv;
	uint32_t lockd_state = 0;
	int ret;

	/*
	* It's reasonable to expect a lockd_vg("sh") here, but it should
	* not actually be needed, because we only report the progress on
	* the same host where the pvmove/lvconvert is happening. This means
	* that the local pvmove/lvconvert/lvpoll commands are updating the
	* local lvmetad with the latest info they have, and we just need to
	* read the latest info that they have put into lvmetad about their
	* progress. No VG lock is needed to protect anything here (we're
	* just reading the VG), and no VG lock is needed to force a VG read
	* from disk to get changes from other hosts, because the only change
	* to the VG we're interested in is the change done locally.
	*/

	vg = vg_read(cmd, id->vg_name, NULL, 0, lockd_state);
	if (vg_read_error(vg)) {
	release_vg(vg);
	log_error("Can't reread VG for %s", id->display_name);
	ret = 0;
	goto out_ret;
	}

	lv = find_lv(vg, id->lv_name);

	if (lv && id->uuid && strcmp(id->uuid, (char *)&lv->lvid))
	lv = NULL;
	if (lv && parms->lv_type && !(lv->status & parms->lv_type))
	lv = NULL;

	if (!lv) {
	if (parms->lv_type == PVMOVE)
	log_verbose("%s: No pvmove in progress - already finished or aborted.",
	id->display_name);
	else
	log_verbose("Can't find LV in %s for %s. Already finished or removed.",
	vg->name, id->display_name);
	ret = 1;
	goto out;
	}

	if (!lv_is_active_locally(lv)) {
	log_verbose("%s: Interrupted: No longer active.", id->display_name);
	ret = 1;
	goto out;
	}

	if (parms->poll_fns->poll_progress(cmd, lv, id->display_name, parms) == PROGRESS_CHECK_FAILED) {
	ret = 0;
	goto out;
	}

	ret = 1;

	out:
	unlock_and_release_vg(cmd, vg, vg->name);
	out_ret:
	return ret;
	}

	static int _lvmpolld_init_poll_vg(struct cmd_context cmd, const char vgname,
	struct volume_group vg, struct processing_handle handle)
	{
	int r;
	struct lv_list *lvl;
	struct logical_volume *lv;
	struct poll_id_list *idl;
	struct poll_operation_id id;
	lvmpolld_parms_t lpdp = (lvmpolld_parms_t ) handle->custom_handle;

	dm_list_iterate_items(lvl, &vg->lvs) {
	lv = lvl->lv;
	if (!(lv->status & lpdp->parms->lv_type))
	continue;

	id.display_name = lpdp->parms->poll_fns->get_copy_name_from_lv(lv);
	if (!id.display_name && !lpdp->parms->aborting)
	continue;

	id.vg_name = lv->vg->name;
	id.lv_name = lv->name;

	if (!*lv->lvid.s) {
	log_print_unless_silent("Missing LV uuid within: %s/%s", id.vg_name, id.lv_name);
	continue;
	}

	id.uuid = lv->lvid.s;

	r = lvmpolld_poll_init(cmd, &id, lpdp->parms);

	if (r && !lpdp->parms->background) {
	if (!(idl = poll_id_list_create(cmd->mem, &id)))
	return ECMD_FAILED;

	dm_list_add(&lpdp->idls, &idl->list);
	}
	}

	return ECMD_PROCESSED;
	}

	static void _lvmpolld_poll_for_all_vgs(struct cmd_context *cmd,
	struct daemon_parms *parms,
	struct processing_handle *handle)
	{
	int r;
	struct dm_list *first;
	struct poll_id_list idl, tlv;
	unsigned finished;
	lvmpolld_parms_t lpdp = {
	.parms = parms
	};

	dm_list_init(&lpdp.idls);

	handle->custom_handle = &lpdp;

	process_each_vg(cmd, 0, NULL, 0, handle, _lvmpolld_init_poll_vg);

	first = dm_list_first(&lpdp.idls);

	while (!dm_list_empty(&lpdp.idls)) {
	dm_list_iterate_items_safe(idl, tlv, &lpdp.idls) {
	r = lvmpolld_request_info(idl->id, lpdp.parms,
	&finished);
	if (!r \|\| finished)
	dm_list_del(&idl->list);
	else if (!parms->aborting)
	report_progress(cmd, idl->id, lpdp.parms);
	}

	if (lpdp.parms->interval)
	dev_close_all();

	_nanosleep(lpdp.parms->interval, 0);
	}

	if (first)
	dm_pool_free(cmd->mem, dm_list_item(first, struct poll_id_list));
	}

	static int _lvmpoll_daemon(struct cmd_context cmd, struct poll_operation_id id,
	struct daemon_parms *parms)
	{
	int r;
	struct processing_handle *handle = NULL;
	unsigned finished = 0;

	if (parms->aborting)
	parms->interval = 0;

	if (id) {
	r = lvmpolld_poll_init(cmd, id, parms);
	if (r && !parms->background) {
	while (1) {
	if (!(r = lvmpolld_request_info(id, parms, &finished)) \|\|
	finished \|\|
	(!parms->aborting && !(r = report_progress(cmd, id, parms))))
	break;

	if (parms->interval)
	dev_close_all();

	_nanosleep(parms->interval, 0);
	}
	}

	return r ? ECMD_PROCESSED : ECMD_FAILED;
	} else {
	/* process all in-flight operations */
	if (!(handle = init_processing_handle(cmd))) {
	log_error("Failed to initialize processing handle.");
	return ECMD_FAILED;
	} else {
	_lvmpolld_poll_for_all_vgs(cmd, parms, handle);
	destroy_processing_handle(cmd, handle);
	return ECMD_PROCESSED;
	}
	}
	}
	#else
	# define _lvmpoll_daemon(cmd, id, parms) (ECMD_FAILED)
	#endif /* LVMPOLLD_SUPPORT */

	/*
	* Only allow one return from poll_daemon() (the parent).
	* If there is a child it must exit (ignoring the memory leak messages).
	* - 'background' is advisory so a child polldaemon may not be used even
	* if it was requested.
	*/
	static int _poll_daemon(struct cmd_context cmd, struct poll_operation_id id,
	struct daemon_parms *parms)
	{
	struct processing_handle *handle = NULL;
	int daemon_mode = 0;
	int ret = ECMD_PROCESSED;

	if (parms->background) {
	daemon_mode = become_daemon(cmd, 0);
	if (daemon_mode == 0)
	return ECMD_PROCESSED; /* Parent */
	else if (daemon_mode == 1)
	parms->progress_display = 0; /* Child */
	/* FIXME Use wait_event (i.e. interval = 0) and */
	/* fork one daemon per copy? */
	}

	/*
	* Process one specific task or all incomplete tasks?
	*/
	if (id) {
	if (!wait_for_single_lv(cmd, id, parms)) {
	stack;
	ret = ECMD_FAILED;
	}
	} else {
	if (!parms->interval)
	parms->interval = find_config_tree_int(cmd, activation_polling_interval_CFG, NULL);
	if (!(handle = init_processing_handle(cmd))) {
	log_error("Failed to initialize processing handle.");
	ret = ECMD_FAILED;
	} else {
	handle->custom_handle = parms;
	_poll_for_all_vgs(cmd, handle);
	}
	}

	if (parms->background && daemon_mode == 1) {
	destroy_processing_handle(cmd, handle);
	/*
	* child was successfully forked:
	* background polldaemon must not return to the caller
	* because it will redundantly continue performing the
	* caller's task (that the parent already performed)
	*/
	/* FIXME Attempt proper cleanup */
	_exit(lvm_return_code(ret));
	}

	destroy_processing_handle(cmd, handle);
	return ret;
	}

	static int _daemon_parms_init(struct cmd_context cmd, struct daemon_parms parms,
	unsigned background, struct poll_functions *poll_fns,
	const char *progress_title, uint64_t lv_type)
	{
	sign_t interval_sign;

	parms->aborting = arg_is_set(cmd, abort_ARG);
	parms->background = background;
	interval_sign = arg_sign_value(cmd, interval_ARG, SIGN_NONE);
	if (interval_sign == SIGN_MINUS) {
	log_error("Argument to --interval cannot be negative.");
	return 0;
	}
	parms->interval = arg_uint_value(cmd, interval_ARG,
	find_config_tree_int(cmd, activation_polling_interval_CFG, NULL));
	parms->wait_before_testing = (interval_sign == SIGN_PLUS);
	parms->progress_title = progress_title;
	parms->lv_type = lv_type;
	parms->poll_fns = poll_fns;

	if (parms->interval && !parms->aborting)
	log_verbose("Checking progress %s waiting every %u seconds.",
	(parms->wait_before_testing ? "after" : "before"),
	parms->interval);

	parms->progress_display = parms->interval ? 1 : 0;

	return 1;
	}

	int poll_daemon(struct cmd_context *cmd, unsigned background,
	uint64_t lv_type, struct poll_functions *poll_fns,
	const char progress_title, struct poll_operation_id id)
	{
	struct daemon_parms parms;

	if (!_daemon_parms_init(cmd, &parms, background, poll_fns, progress_title, lv_type))
	return_EINVALID_CMD_LINE;

	if (lvmpolld_use())
	return _lvmpoll_daemon(cmd, id, &parms);
	else {
	/* classical polling allows only PMVOVE or 0 values */
	parms.lv_type &= PVMOVE;
	return _poll_daemon(cmd, id, &parms);
	}
	}