lvm2/lib/metadata/metadata.c

/*
 * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.   
 * Copyright (C) 2004 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 General Public License v.2.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "lib.h"
#include "pool.h"
#include "device.h"
#include "metadata.h"
#include "toolcontext.h"
#include "lvm-string.h"
#include "lvmcache.h"
#include "memlock.h"

static int _add_pv_to_vg(struct format_instance *fid, struct volume_group *vg,
			 const char *pv_name)
{
	struct pv_list *pvl;
	struct physical_volume *pv;
	struct pool *mem = fid->fmt->cmd->mem;
	struct list mdas;

	log_verbose("Adding physical volume '%s' to volume group '%s'",
		    pv_name, vg->name);

	if (!(pvl = pool_zalloc(mem, sizeof(*pvl)))) {
		log_error("pv_list allocation for '%s' failed", pv_name);
		return 0;
	}

	list_init(&mdas);
	if (!(pv = pv_read(fid->fmt->cmd, pv_name, &mdas, NULL))) {
		log_error("%s not identified as an existing physical volume",
			  pv_name);
		return 0;
	}

	if (*pv->vg_name) {
		log_error("Physical volume '%s' is already in volume group "
			  "'%s'", pv_name, pv->vg_name);
		return 0;
	}

	if (pv->fmt != fid->fmt) {
		log_error("Physical volume %s is of different format type (%s)",
			  pv_name, pv->fmt->name);
		return 0;
	}

	if (!(pv->vg_name = pool_strdup(mem, vg->name))) {
		log_error("vg->name allocation failed for '%s'", pv_name);
		return 0;
	}

	/* Units of 512-byte sectors */
	pv->pe_size = vg->extent_size;

	/* FIXME Do proper rounding-up alignment? */
	/* Reserved space for label; this holds 0 for PVs created by LVM1 */
	if (pv->pe_start < PE_ALIGN)
		pv->pe_start = PE_ALIGN;

	/*
	 * The next two fields should be corrected
	 * by fid->pv_setup.
	 */
	pv->pe_count = (pv->size - pv->pe_start) / vg->extent_size;

	pv->pe_alloc_count = 0;

	if (!fid->fmt->ops->pv_setup(fid->fmt, UINT64_C(0), 0,
				     vg->extent_size, 0, UINT64_C(0),
				     &fid->metadata_areas, pv, vg)) {
		log_error("Format-specific setup of physical volume '%s' "
			  "failed.", pv_name);
		return 0;
	}

	if (find_pv_in_vg(vg, pv_name)) {
		log_error("Physical volume '%s' listed more than once.",
			  pv_name);
		return 0;
	}

	if (vg->pv_count && (vg->pv_count == vg->max_pv)) {
		log_error("No space for '%s' - volume group '%s' "
			  "holds max %d physical volume(s).", pv_name,
			  vg->name, vg->max_pv);
		return 0;
	}

	pvl->pv = pv;

	list_add(&vg->pvs, &pvl->list);
	vg->pv_count++;
	vg->extent_count += pv->pe_count;
	vg->free_count += pv->pe_count;

	return 1;
}

int vg_rename(struct cmd_context *cmd, struct volume_group *vg,
	      const char *new_name)
{
	struct pool *mem = cmd->mem;
	struct physical_volume *pv;
	struct list *pvh;

	if (!(vg->name = pool_strdup(mem, new_name))) {
		log_error("vg->name allocation failed for '%s'", new_name);
		return 0;
	}

	list_iterate(pvh, &vg->pvs) {
		pv = list_item(pvh, struct pv_list)->pv;
		if (!(pv->vg_name = pool_strdup(mem, new_name))) {
			log_error("pv->vg_name allocation failed for '%s'",
				  dev_name(pv->dev));
			return 0;
		}
	}

	return 1;
}

int vg_extend(struct format_instance *fid,
	      struct volume_group *vg, int pv_count, char **pv_names)
{
	int i;

	/* attach each pv */
	for (i = 0; i < pv_count; i++)
		if (!_add_pv_to_vg(fid, vg, pv_names[i])) {
			log_error("Unable to add physical volume '%s' to "
				  "volume group '%s'.", pv_names[i], vg->name);
			return 0;
		}

/* FIXME Decide whether to initialise and add new mdahs to format instance */

	return 1;
}

const char *strip_dir(const char *vg_name, const char *dev_dir)
{
	size_t len = strlen(dev_dir);
	if (!strncmp(vg_name, dev_dir, len))
		vg_name += len;

	return vg_name;
}

struct volume_group *vg_create(struct cmd_context *cmd, const char *vg_name,
			       uint32_t extent_size, uint32_t max_pv,
			       uint32_t max_lv, alloc_policy_t alloc,
			       int pv_count, char **pv_names)
{
	struct volume_group *vg;
	struct pool *mem = cmd->mem;
	int consistent = 0;
	int old_partial;

	if (!(vg = pool_zalloc(mem, sizeof(*vg)))) {
		stack;
		return NULL;
	}

	/* is this vg name already in use ? */
	old_partial = partial_mode();
	init_partial(1);
	if (vg_read(cmd, vg_name, &consistent)) {
		log_err("A volume group called '%s' already exists.", vg_name);
		goto bad;
	}
	init_partial(old_partial);

	if (!id_create(&vg->id)) {
		log_err("Couldn't create uuid for volume group '%s'.", vg_name);
		goto bad;
	}

	/* Strip dev_dir if present */
	vg_name = strip_dir(vg_name, cmd->dev_dir);

	vg->cmd = cmd;

	if (!(vg->name = pool_strdup(mem, vg_name))) {
		stack;
		goto bad;
	}

	vg->seqno = 0;

	vg->status = (RESIZEABLE_VG | LVM_READ | LVM_WRITE);
	vg->system_id = pool_alloc(mem, NAME_LEN);
	*vg->system_id = '\0';

	vg->extent_size = extent_size;
	vg->extent_count = 0;
	vg->free_count = 0;

	vg->max_lv = max_lv;
	vg->max_pv = max_pv;

	vg->alloc = alloc;

	vg->pv_count = 0;
	list_init(&vg->pvs);

	vg->lv_count = 0;
	list_init(&vg->lvs);

	vg->snapshot_count = 0;
	list_init(&vg->snapshots);

	list_init(&vg->tags);

	if (!(vg->fid = cmd->fmt->ops->create_instance(cmd->fmt, vg_name,
						       NULL))) {
		log_error("Failed to create format instance");
		goto bad;
	}

	if (vg->fid->fmt->ops->vg_setup &&
	    !vg->fid->fmt->ops->vg_setup(vg->fid, vg)) {
		log_error("Format specific setup of volume group '%s' failed.",
			  vg_name);
		goto bad;
	}

	/* attach the pv's */
	if (!vg_extend(vg->fid, vg, pv_count, pv_names))
		goto bad;

	return vg;

      bad:
	pool_free(mem, vg);
	return NULL;
}

/* Sizes in sectors */
struct physical_volume *pv_create(const struct format_type *fmt,
				  struct device *dev,
				  struct id *id, uint64_t size,
				  uint64_t pe_start,
				  uint32_t existing_extent_count,
				  uint32_t existing_extent_size,
				  int pvmetadatacopies,
				  uint64_t pvmetadatasize, struct list *mdas)
{
	struct pool *mem = fmt->cmd->mem;
	struct physical_volume *pv = pool_alloc(mem, sizeof(*pv));

	if (!pv) {
		stack;
		return NULL;
	}

	if (!id)
		id_create(&pv->id);
	else
		memcpy(&pv->id, id, sizeof(*id));

	pv->dev = dev;

	if (!(pv->vg_name = pool_zalloc(mem, NAME_LEN))) {
		stack;
		goto bad;
	}

	pv->status = ALLOCATABLE_PV;

	if (!dev_get_size(pv->dev, &pv->size)) {
		log_error("%s: Couldn't get size.", dev_name(pv->dev));
		goto bad;
	}

	if (size) {
		if (size > pv->size)
			log_print("WARNING: %s: Overriding real size. "
				  "You could lose data.", dev_name(pv->dev));
		log_verbose("%s: Pretending size is %" PRIu64 " sectors.",
			    dev_name(pv->dev), size);
		pv->size = size;
	}

	if (pv->size < PV_MIN_SIZE) {
		log_error("%s: Size must exceed minimum of %ld sectors.",
			  dev_name(pv->dev), PV_MIN_SIZE);
		goto bad;
	}

	pv->pe_size = 0;
	pv->pe_start = 0;
	pv->pe_count = 0;
	pv->pe_alloc_count = 0;
	pv->fmt = fmt;

	list_init(&pv->tags);

	if (!fmt->ops->pv_setup(fmt, pe_start, existing_extent_count,
				existing_extent_size,
				pvmetadatacopies, pvmetadatasize, mdas,
				pv, NULL)) {
		log_error("%s: Format-specific setup of physical volume "
			  "failed.", dev_name(pv->dev));
		goto bad;
	}
	return pv;

      bad:
	pool_free(mem, pv);
	return NULL;
}

struct pv_list *find_pv_in_vg(struct volume_group *vg, const char *pv_name)
{
	struct list *pvh;
	struct pv_list *pvl;

	list_iterate(pvh, &vg->pvs) {
		pvl = list_item(pvh, struct pv_list);
		if (pvl->pv->dev == dev_cache_get(pv_name, vg->cmd->filter))
			return pvl;
	}

	return NULL;
}

int pv_is_in_vg(struct volume_group *vg, struct physical_volume *pv)
{
	struct list *pvh;

	list_iterate(pvh, &vg->pvs) {
		if (pv == list_item(pvh, struct pv_list)->pv)
			 return 1;
	}

	return 0;
}

struct physical_volume *find_pv_in_vg_by_uuid(struct volume_group *vg,
					      struct id *id)
{
	struct list *pvh;
	struct pv_list *pvl;

	list_iterate(pvh, &vg->pvs) {
		pvl = list_item(pvh, struct pv_list);
		if (id_equal(&pvl->pv->id, id))
			return pvl->pv;
	}

	return NULL;
}

struct lv_list *find_lv_in_vg(struct volume_group *vg, const char *lv_name)
{
	struct list *lvh;
	struct lv_list *lvl;
	const char *ptr;

	/* Use last component */
	if ((ptr = strrchr(lv_name, '/')))
		ptr++;
	else
		ptr = lv_name;

	list_iterate(lvh, &vg->lvs) {
		lvl = list_item(lvh, struct lv_list);
		if (!strcmp(lvl->lv->name, ptr))
			return lvl;
	}

	return NULL;
}

struct lv_list *find_lv_in_vg_by_lvid(struct volume_group *vg,
				      const union lvid *lvid)
{
	struct list *lvh;
	struct lv_list *lvl;

	list_iterate(lvh, &vg->lvs) {
		lvl = list_item(lvh, struct lv_list);
		if (!strncmp(lvl->lv->lvid.s, lvid->s, sizeof(*lvid)))
			return lvl;
	}

	return NULL;
}

struct logical_volume *find_lv(struct volume_group *vg, const char *lv_name)
{
	struct lv_list *lvl = find_lv_in_vg(vg, lv_name);
	return lvl ? lvl->lv : NULL;
}

struct physical_volume *find_pv(struct volume_group *vg, struct device *dev)
{
	struct list *pvh;
	struct physical_volume *pv;

	list_iterate(pvh, &vg->pvs) {
		pv = list_item(pvh, struct pv_list)->pv;

		if (dev == pv->dev)
			return pv;
	}
	return NULL;
}

struct physical_volume *find_pv_by_name(struct cmd_context *cmd,
					const char *pv_name)
{
	struct physical_volume *pv;

	if (!(pv = pv_read(cmd, pv_name, NULL, NULL))) {
		log_error("Physical volume %s not found", pv_name);
		return NULL;
	}

	if (!pv->vg_name[0]) {
		log_error("Physical volume %s not in a volume group", pv_name);
		return NULL;
	}

	return pv;
}

/* Find segment at a given logical extent in an LV */
struct lv_segment *find_seg_by_le(struct logical_volume *lv, uint32_t le)
{
	struct list *segh;
	struct lv_segment *seg;

	list_iterate(segh, &lv->segments) {
		seg = list_item(segh, struct lv_segment);
		if (le >= seg->le && le < seg->le + seg->len)
			return seg;
	}

	return NULL;
}

int vg_remove(struct volume_group *vg)
{
	struct list *mdah;
	struct metadata_area *mda;

	/* FIXME Improve recovery situation? */
	/* Remove each copy of the metadata */
	list_iterate(mdah, &vg->fid->metadata_areas) {
		mda = list_item(mdah, struct metadata_area);
		if (mda->ops->vg_remove &&
		    !mda->ops->vg_remove(vg->fid, vg, mda)) {
			stack;
			return 0;
		}
	}

	return 1;
}

/*
 * After vg_write() returns success,
 * caller MUST call either vg_commit() or vg_revert()
 */
int vg_write(struct volume_group *vg)
{
	struct list *mdah, *mdah2;
	struct metadata_area *mda;

	if (vg->status & PARTIAL_VG) {
		log_error("Cannot change metadata for partial volume group %s",
			  vg->name);
		return 0;
	}

	if (list_empty(&vg->fid->metadata_areas)) {
		log_error("Aborting vg_write: No metadata areas to write to!");
		return 0;
	}

	vg->seqno++;

	/* Write to each copy of the metadata area */
	list_iterate(mdah, &vg->fid->metadata_areas) {
		mda = list_item(mdah, struct metadata_area);
		if (!mda->ops->vg_write) {
			log_error("Format does not support writing volume"
				  "group metadata areas");
			/* Revert */
			list_uniterate(mdah2, &vg->fid->metadata_areas, mdah) {
				mda = list_item(mdah2, struct metadata_area);
				if (mda->ops->vg_revert &&
				    !mda->ops->vg_revert(vg->fid, vg, mda)) {
					stack;
				}
			}
			return 0;
		}
		if (!mda->ops->vg_write(vg->fid, vg, mda)) {
			stack;
			/* Revert */
			list_uniterate(mdah2, &vg->fid->metadata_areas, mdah) {
				mda = list_item(mdah2, struct metadata_area);
				if (mda->ops->vg_revert &&
				    !mda->ops->vg_revert(vg->fid, vg, mda)) {
					stack;
				}
			}
			return 0;
		}
	}

	return 1;
}

/* Commit pending changes */
int vg_commit(struct volume_group *vg)
{
	struct list *mdah;
	struct metadata_area *mda;
	int cache_updated = 0;
	int failed = 0;

	/* Commit to each copy of the metadata area */
	list_iterate(mdah, &vg->fid->metadata_areas) {
		mda = list_item(mdah, struct metadata_area);
		failed = 0;
		if (mda->ops->vg_commit &&
		    !mda->ops->vg_commit(vg->fid, vg, mda)) {
			stack;
			failed = 1;
		}
		/* Update cache first time we succeed */
		if (!failed && !cache_updated) {
			lvmcache_update_vg(vg);
			cache_updated = 1;
		}

	}

	/* If at least one mda commit succeeded, it was committed */
	return cache_updated;
}

/* Don't commit any pending changes */
int vg_revert(struct volume_group *vg)
{
	struct list *mdah;
	struct metadata_area *mda;

	list_iterate(mdah, &vg->fid->metadata_areas) {
		mda = list_item(mdah, struct metadata_area);
		if (mda->ops->vg_revert &&
		    !mda->ops->vg_revert(vg->fid, vg, mda)) {
			stack;
		}
	}

	return 1;
}

/* Make orphan PVs look like a VG */
static struct volume_group *_vg_read_orphans(struct cmd_context *cmd)
{
	struct lvmcache_vginfo *vginfo;
	struct list *ih;
	struct device *dev;
	struct pv_list *pvl;
	struct volume_group *vg;
	struct physical_volume *pv;

	if (!(vginfo = vginfo_from_vgname(ORPHAN))) {
		stack;
		return NULL;
	}

	if (!(vg = pool_zalloc(cmd->mem, sizeof(*vg)))) {
		log_error("vg allocation failed");
		return NULL;
	}
	list_init(&vg->pvs);
	list_init(&vg->lvs);
	list_init(&vg->snapshots);
	list_init(&vg->tags);
	vg->cmd = cmd;
	if (!(vg->name = pool_strdup(cmd->mem, ORPHAN))) {
		log_error("vg name allocation failed");
		return NULL;
	}

	list_iterate(ih, &vginfo->infos) {
		dev = list_item(ih, struct lvmcache_info)->dev;
		if (!(pv = pv_read(cmd, dev_name(dev), NULL, NULL))) {
			continue;
		}
		if (!(pvl = pool_zalloc(cmd->mem, sizeof(*pvl)))) {
			log_error("pv_list allocation failed");
			return NULL;
		}
		pvl->pv = pv;
		list_add(&vg->pvs, &pvl->list);
		vg->pv_count++;
	}

	return vg;
}

/* Caller sets consistent to 1 if it's safe for vg_read to correct
 * inconsistent metadata on disk (i.e. the VG write lock is held).
 * This guarantees only consistent metadata is returned unless PARTIAL_VG.
 * If consistent is 0, caller must check whether consistent == 1 on return
 * and take appropriate action if it isn't (e.g. abort; get write lock 
 * and call vg_read again).
 */
struct volume_group *vg_read(struct cmd_context *cmd, const char *vgname,
			     int *consistent)
{
	struct format_instance *fid;
	const struct format_type *fmt;
	struct volume_group *vg, *correct_vg = NULL;
	struct list *mdah;
	struct metadata_area *mda;
	int inconsistent = 0;

	if (!*vgname) {
		*consistent = 1;
		return _vg_read_orphans(cmd);
	}

	/* Find the vgname in the cache */
	/* If it's not there we must do full scan to be completely sure */
	if (!(fmt = fmt_from_vgname(vgname))) {
		lvmcache_label_scan(cmd, 0);
		if (!(fmt = fmt_from_vgname(vgname))) {
			if (memlock()) {
				stack;
				return NULL;
			}
			lvmcache_label_scan(cmd, 1);
			if (!(fmt = fmt_from_vgname(vgname))) {
				stack;
				return NULL;
			}
		}
	}

	/* create format instance with appropriate metadata area */
	if (!(fid = fmt->ops->create_instance(fmt, vgname, NULL))) {
		log_error("Failed to create format instance");
		return NULL;
	}

	/* Ensure contents of all metadata areas match - else do recovery */
	list_iterate(mdah, &fid->metadata_areas) {
		mda = list_item(mdah, struct metadata_area);
		if (!(vg = mda->ops->vg_read(fid, vgname, mda))) {
			inconsistent = 1;
			continue;
		}
		if (!correct_vg) {
			correct_vg = vg;
			continue;
		}
		/* FIXME Also ensure contents same - checksum compare? */
		if (correct_vg->seqno != vg->seqno) {
			inconsistent = 1;
			if (vg->seqno > correct_vg->seqno)
				correct_vg = vg;
		}
	}

	/* Failed to find VG */
	if (!correct_vg) {
		stack;
		return NULL;
	}

	lvmcache_update_vg(correct_vg);

	if (inconsistent) {
		if (!*consistent)
			return correct_vg;

		/* Don't touch partial volume group metadata */
		/* Should be fixed manually with vgcfgbackup/restore etc. */
		if ((correct_vg->status & PARTIAL_VG)) {
			log_error("Inconsistent metadata copies found for "
				  "partial volume group %s", vgname);
			*consistent = 0;
			return correct_vg;
		}

		log_print("Inconsistent metadata copies found - updating "
			  "to use version %u", correct_vg->seqno);
		if (!vg_write(correct_vg)) {
			log_error("Automatic metadata correction failed");
			return NULL;
		}
	}

	if ((correct_vg->status & PVMOVE) && !pvmove_mode()) {
		log_error("WARNING: Interrupted pvmove detected in "
			  "volume group %s", correct_vg->name);
		log_error("Please restore the metadata by running "
			  "vgcfgrestore.");
		return NULL;
	}

	*consistent = 1;
	return correct_vg;
}

/* This is only called by lv_from_lvid, which is only called from 
 * activate.c so we know the appropriate VG lock is already held and 
 * the vg_read is therefore safe.
 */
struct volume_group *vg_read_by_vgid(struct cmd_context *cmd, const char *vgid)
{
	const char *vgname;
	struct list *vgnames, *slh;
	struct volume_group *vg;
	struct lvmcache_vginfo *vginfo;
	int consistent = 0;

	/* Is corresponding vgname already cached? */
	if ((vginfo = vginfo_from_vgid(vgid)) &&
	    vginfo->vgname && *vginfo->vgname) {
		if ((vg = vg_read(cmd, vginfo->vgname, &consistent)) &&
		    !strncmp(vg->id.uuid, vgid, ID_LEN)) {
			if (!consistent) {
				log_error("Volume group %s metadata is "
					  "inconsistent", vginfo->vgname);
				return NULL;
			}
			return vg;
		}
	}

	/* Mustn't scan if memory locked: ensure cache gets pre-populated! */
	if (memlock())
		return NULL;

	/* FIXME Need a genuine read by ID here - don't vg_read by name! */
	/* FIXME Disabled vgrenames while active for now because we aren't
	 *       allowed to do a full scan here any more. */

	// The slow way - full scan required to cope with vgrename 
	if (!(vgnames = get_vgs(cmd, 1))) {
		log_error("vg_read_by_vgid: get_vgs failed");
		return NULL;
	}

	list_iterate(slh, vgnames) {
		vgname = list_item(slh, struct str_list)->str;
		if (!vgname || !*vgname)
			continue;	// FIXME Unnecessary? 
		consistent = 0;
		if ((vg = vg_read(cmd, vgname, &consistent)) &&
		    !strncmp(vg->id.uuid, vgid, ID_LEN)) {
			if (!consistent) {
				log_error("Volume group %s metadata is "
					  "inconsistent", vgname);
				return NULL;
			}
			return vg;
		}
	}

	return NULL;
}

/* Only called by activate.c */
struct logical_volume *lv_from_lvid(struct cmd_context *cmd, const char *lvid_s)
{
	struct lv_list *lvl;
	struct volume_group *vg;
	const union lvid *lvid;

	lvid = (const union lvid *) lvid_s;

	log_very_verbose("Finding volume group for uuid %s", lvid_s);
	if (!(vg = vg_read_by_vgid(cmd, lvid->id[0].uuid))) {
		log_error("Volume group for uuid not found: %s", lvid_s);
		return NULL;
	}

	log_verbose("Found volume group \"%s\"", vg->name);
	if (vg->status & EXPORTED_VG) {
		log_error("Volume group \"%s\" is exported", vg->name);
		return NULL;
	}
	if (!(lvl = find_lv_in_vg_by_lvid(vg, lvid))) {
		log_very_verbose("Can't find logical volume id %s", lvid_s);
		return NULL;
	}

	return lvl->lv;
}

/* FIXME Use label functions instead of PV functions */
struct physical_volume *pv_read(struct cmd_context *cmd, const char *pv_name,
				struct list *mdas, uint64_t *label_sector)
{
	struct physical_volume *pv;
	struct label *label;
	struct lvmcache_info *info;
	struct device *dev;

	if (!(dev = dev_cache_get(pv_name, cmd->filter))) {
		stack;
		return 0;
	}

	if (!(label_read(dev, &label))) {
		log_error("No physical volume label read from %s", pv_name);
		return 0;
	}

	info = (struct lvmcache_info *) label->info;
	if (label_sector && *label_sector)
		*label_sector = label->sector;

	if (!(pv = pool_zalloc(cmd->mem, sizeof(*pv)))) {
		log_error("pv allocation for '%s' failed", pv_name);
		return 0;
	}

	list_init(&pv->tags);

	/* FIXME Move more common code up here */
	if (!(info->fmt->ops->pv_read(info->fmt, pv_name, pv, mdas))) {
		log_error("Failed to read existing physical volume '%s'",
			  pv_name);
		return 0;
	}

	if (!pv->size)
		return NULL;
	else
		return pv;
}

/* May return empty list */
struct list *get_vgs(struct cmd_context *cmd, int full_scan)
{
	return lvmcache_get_vgnames(cmd, full_scan);
}

struct list *get_pvs(struct cmd_context *cmd)
{
	struct list *results;
	const char *vgname;
	struct list *pvh, *tmp;
	struct list *vgnames, *slh;
	struct volume_group *vg;
	int consistent = 0;
	int old_partial;
	int old_pvmove;

	lvmcache_label_scan(cmd, 0);

	if (!(results = pool_alloc(cmd->mem, sizeof(*results)))) {
		log_error("PV list allocation failed");
		return NULL;
	}

	list_init(results);

	/* Get list of VGs */
	if (!(vgnames = get_vgs(cmd, 0))) {
		log_error("get_pvs: get_vgs failed");
		return NULL;
	}

	/* Read every VG to ensure cache consistency */
	/* Orphan VG is last on list */
	old_partial = partial_mode();
	old_pvmove = pvmove_mode();
	init_partial(1);
	init_pvmove(1);
	list_iterate(slh, vgnames) {
		vgname = list_item(slh, struct str_list)->str;
		if (!vgname)
			continue;	/* FIXME Unnecessary? */
		consistent = 0;
		if (!(vg = vg_read(cmd, vgname, &consistent))) {
			stack;
			continue;
		}
		if (!consistent)
			log_print("Warning: Volume Group %s is not consistent",
				  vgname);

		/* Move PVs onto results list */
		list_iterate_safe(pvh, tmp, &vg->pvs) {
			list_add(results, pvh);
		}
	}
	init_pvmove(old_pvmove);
	init_partial(old_partial);

	return results;
}

int pv_write(struct cmd_context *cmd, struct physical_volume *pv,
	     struct list *mdas, int64_t label_sector)
{
	if (!pv->fmt->ops->pv_write) {
		log_error("Format does not support writing physical volumes");
		return 0;
	}

	if (*pv->vg_name || pv->pe_alloc_count) {
		log_error("Assertion failed: can't _pv_write non-orphan PV "
			  "(in VG %s)", pv->vg_name);
		return 0;
	}

	if (!pv->fmt->ops->pv_write(pv->fmt, pv, mdas, label_sector)) {
		stack;
		return 0;
	}

	return 1;
}