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[thin-repair, thin_dump] When repairing we now hunt for the best btree roots.

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We've had a trickle of users who accidentally activate the same pool on a
VM and host at the same time.  Typically the host doesn't do any IO, but
the kernel will still rewrite the superblock on shutdown.  This leaves
the superblock pointing to very out of date btree roots and so we get
massive metadata loss.

This patch changes thin_repair, and thin_dump --repair.  They now hunt
for the most recent, undamaged and consistent roots of the device and
mapping trees, and use that as the starting point of the repair.
This commit is contained in:
Joe Thornber 2019-04-17 12:17:13 +01:00
parent b027a1039f
commit 9e20465fd1
4 changed files with 560 additions and 362 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

888
thin-provisioning/metadata_dumper.cc
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@ -19,6 +19,8 @@
#include "thin-provisioning/emitter.h"
#include "thin-provisioning/metadata_dumper.h"
#include "thin-provisioning/mapping_tree.h"
#include "persistent-data/data-structures/simple_traits.h"
#include "persistent-data/file_utils.h"
#include <map>
#include <vector>
@ -26,349 +28,7 @@
using namespace persistent_data;
using namespace thin_provisioning;
//----------------------------------------------------------------
// We only need to examine the mapping tree, and device details tree.
// The space maps can be inferred.
// Repair process:
// - We only trigger the repair process if there's damage when walking from
// the roots given in the superblock.
// - If there is damage, then we try and find the most recent roots with the
// least corruption. We're seeing cases where just the superblock has been
// trashed so finding the best roots is essential, and sadly non trivial.
// Finding roots:
// This is about classifying and summarising btree nodes. The use of a btree
// node may not be obvious when inspecting it in isolation. But more information
// may be gleaned by examining child and sibling nodes.
//
// So the process is:
// - scan every metadata block, summarising it's potential uses.
// - repeatedly iterate those summaries until we can glean no more useful information.
// - sort candidate roots, choose best
// Summary information:
// - btree; mapping top level, mapping bottom level, device tree (more than one possible)
// - node type; internal or leaf
// - age; for mapping trees we can infer a minimum age from the block/time
// values. In addition two similar leaf nodes can be compared by looking
// at the block/time for _specific_ blocks. This means we can define an ordering
// on the ages, but not equality.
// - Device details can be aged based on the last_snapshot_time field.
// Iteration of summary info:
// - constraints propagate both up and down the trees. eg, node 'a' may
// be ambiguous (all internal nodes are ambigous). If we find that all it's
// children are device details trees, then we infer that this is too and lose
// the ambiguity. Now if it has a sibling we can infer on this too.
// - Some characteristics only propagate upwards. eg, age. So we need two monoids
// for summary info (up and down).
namespace {
using namespace std;
using namespace boost;
using namespace persistent_data::btree_detail;
using namespace thin_provisioning::device_tree_detail;
enum btree_type_bit {
TOP_LEVEL,
BOTTOM_LEVEL,
DEVICE_DETAILS
};
struct node_info {
node_info()
: types(0),
b(0),
values(0),
orphan(true),
is_leaf(true),
key_low(0),
key_high(0),
age(0) {
}
void add_type(btree_type_bit b) {
types = types | (1 << b);
}
void clear_type(btree_type_bit b) {
types = types & ~(1 << b);
}
bool has_type(btree_type_bit b) const {
return types & (1 << b);
}
// Indicate corruption by having no fields set
unsigned types;
// common
block_address b;
unsigned values;
bool orphan;
bool is_leaf;
uint64_t key_low;
uint64_t key_high;
set<uint32_t> devices;
uint32_t age;
};
using info_map = map<block_address, node_info>;
bool is_btree_node(block_manager<> &bm, block_address b) {
auto v = create_btree_node_validator();
auto rr = bm.read_lock(b);
return v->check_raw(rr.data());
}
uint32_t get_dd_age(device_details const &dd) {
return max(dd.creation_time_, dd.snapshotted_time_);
}
void scan_initial_infos(block_manager<> &bm, info_map &result) {
for (block_address b = 0; b < bm.get_nr_blocks(); b++) {
if (!is_btree_node(bm, b))
continue;
node_info info;
info.b = b;
auto rr = bm.read_lock(b);
auto hdr = reinterpret_cast<node_header const *>(rr.data());
auto flags = to_cpu<uint32_t>(hdr->flags);
if (flags & INTERNAL_NODE) {
info.is_leaf = false;
info.add_type(TOP_LEVEL);
info.add_type(BOTTOM_LEVEL);
info.add_type(DEVICE_DETAILS);
} else {
info.is_leaf = true;
auto vsize = to_cpu<uint32_t>(hdr->value_size);
info.values = to_cpu<uint32_t>(hdr->nr_entries);
if (vsize == sizeof(device_details_traits::disk_type)) {
info.add_type(DEVICE_DETAILS);
auto n = to_node<device_details_traits>(rr);
if (n.get_nr_entries()) {
info.key_low = n.key_at(0);
info.key_high = n.key_at(n.get_nr_entries() - 1);
}
for (unsigned i = 0; i < n.get_nr_entries(); i++)
info.age = max(info.age, get_dd_age(n.value_at(i)));
} else if (vsize == sizeof(uint64_t)) {
info.add_type(BOTTOM_LEVEL);
// This can only be a top level leaf if all the values are
// blocks on the metadata device.
auto is_top_level = true;
auto n = to_node<block_traits>(rr);
if (n.get_nr_entries()) {
info.key_low = n.key_at(0);
info.key_high = n.key_at(n.get_nr_entries() - 1);
}
for (unsigned i = 0; i < n.get_nr_entries(); i++) {
if (n.value_at(i) >= bm.get_nr_blocks()) {
is_top_level = false;
break;
}
}
if (is_top_level)
info.add_type(TOP_LEVEL);
} else
continue;
}
result.insert(make_pair(b, info));
}
}
bool merge_types(node_info &parent, node_info const &child, btree_type_bit b) {
if (parent.has_type(b) && !child.has_type(b)) {
parent.clear_type(b);
return true;
}
return false;
}
// return true if something changed
bool merge_from_below(node_info &parent, node_info const &child) {
bool changed = false;
changed = merge_types(parent, child, TOP_LEVEL) ||
merge_types(parent, child, BOTTOM_LEVEL) ||
merge_types(parent, child, DEVICE_DETAILS);
return changed;
}
void fail(node_info &n) {
n.types = 0;
}
bool failed(node_info const &n) {
return n.types == 0;
}
bool iterate_infos_(block_manager<> &bm, info_map &infos) {
bool changed = false;
for (auto &p : infos) {
auto &parent = p.second;
if (parent.is_leaf)
continue;
// values refer to blocks, so we should have infos for them.
auto rr = bm.read_lock(p.first);
auto n = to_node<block_traits>(rr);
uint64_t key_low = 0;
unsigned values = 0;
for (unsigned i = 0; i < n.get_nr_entries(); i++) {
auto it = infos.find(n.value_at(i));
if (it == infos.end()) {
fail(parent);
break;
}
auto &child = it->second;
// we use the keys to help decide if this is a valid child
if (child.key_low <= key_low) {
fail(parent);
break;
} else
key_low = child.key_high;
changed = merge_from_below(parent, child) || changed;
if (parent.has_type(DEVICE_DETAILS) && child.age > parent.age) {
changed = true;
parent.age = child.age;
}
values += child.values;
}
// We don't clear the orphan flags until we know the parent is good
if (!failed(parent)) {
parent.values = values;
for (unsigned i = 0; i < n.get_nr_entries(); i++) {
auto it = infos.find(n.value_at(i));
if (it == infos.end())
throw runtime_error("no child info, but it was there a moment ago");
auto &child = it->second;
child.orphan = false;
}
}
}
return changed;
}
void iterate_infos(block_manager<> &bm, info_map &infos) {
while (iterate_infos_(bm, infos))
;
}
bool trees_are_compatible(node_info const &mapping, node_info const &devices) {
for (auto thin_id : mapping.devices)
if (devices.devices.find(thin_id) == devices.devices.end())
return false;
return true;
}
bool cmp_mapping_info(node_info const &lhs, node_info const &rhs) {
return lhs.age > rhs.age;
}
bool has_type(node_info const &i, unsigned bit) {
return i.types & (1 << bit);
}
vector<node_info>
extract_mapping_candidates(info_map const &infos) {
vector<node_info> results;
for (auto const &p : infos)
if (p.second.orphan && has_type(p.second, TOP_LEVEL))
results.push_back(p.second);
//sort(results.begin(), results.end(), cmp_mapping_info);
return results;
}
bool cmp_device_info(node_info const &lhs, node_info const &rhs) {
// FIXME: finish
return false;
//return lhs.dd_age > rhs.dd_age;
}
vector<node_info>
extract_device_candidates(info_map const &infos) {
vector<node_info> results;
for (auto const &p : infos)
if (p.second.orphan && has_type(p.second, DEVICE_DETAILS))
results.push_back(p.second);
sort(results.begin(), results.end(), cmp_device_info);
return results;
}
// Returns <mapping root>, <dev details root>
//pair<block_address, block_address>
void
find_best_roots(block_manager<> &bm) {
info_map infos;
scan_initial_infos(bm, infos);
iterate_infos(bm, infos);
// These will be sorted into best first order
vector<node_info> mapping_candidates = extract_mapping_candidates(infos);
vector<node_info> device_candidates = extract_device_candidates(infos);
cerr << "mapping candidates (" << mapping_candidates.size() << "):\n";
for (auto const &i : mapping_candidates)
cerr << i.b << ", tree size = " << i.values << ", age = " << i.age << "\n";
cerr << "\ndevice candidates (" << device_candidates.size() << "):\n";
for (auto const &i : device_candidates)
cerr << i.b << ", tree size = " << i.values << ", age = " << i.age << "\n";
#if 0
// Choose the best mapping tree, and then the best device tree
// that is compatible.
for (auto &m : mapping_candidates)
for (auto &d : device_candidates)
if (trees_are_compatible(m, d))
return make_pair(m.b, d.b);
#endif
// throw runtime_error("no compatible mapping/device trees");
}
}
#define SHOW_WORKING 0
//----------------------------------------------------------------
@ -453,6 +113,479 @@ namespace {
dd_map dd_;
};
struct d_thin_id_extractor : public device_tree_detail::device_visitor {
void visit(block_address dev_id, device_tree_detail::device_details const &dd) {
dd_.insert(dev_id);
}
set<uint32_t> dd_;
};
set<uint32_t>
get_dev_ids(transaction_manager &tm, block_address root) {
d_thin_id_extractor de;
fatal_details_damage dv;
auto tree = device_tree(tm, root, device_tree_detail::device_details_traits::ref_counter());
walk_device_tree(tree, de, dv);
return de.dd_;
}
struct m_thin_id_extractor : public mapping_tree_detail::device_visitor {
void visit(btree_path const &path, block_address dtree_root) {
dd_.insert(path[0]);
}
set<uint32_t> dd_;
};
set<uint32_t>
get_map_ids(transaction_manager &tm, block_address root) {
m_thin_id_extractor me;
fatal_mapping_damage mv;
auto tree = dev_tree(tm, root, mapping_tree_detail::mtree_traits::ref_counter(tm));
walk_mapping_tree(tree, me, mv);
return me.dd_;
}
}
// We only need to examine the mapping tree, and device details tree.
// The space maps can be inferred.
// Repair process:
// - We only trigger the repair process if there's damage when walking from
// the roots given in the superblock.
// - If there is damage, then we try and find the most recent roots with the
// least corruption. We're seeing cases where just the superblock has been
// trashed so finding the best roots is essential, and sadly non trivial.
// Finding roots:
// This is about classifying and summarising btree nodes. The use of a btree
// node may not be obvious when inspecting it in isolation. But more information
// may be gleaned by examining child and sibling nodes.
//
// So the process is:
// - scan every metadata block, summarising it's potential uses.
// - repeatedly iterate those summaries until we can glean no more useful information.
// - sort candidate roots, choose best
// Summary information:
// - btree; mapping top level, mapping bottom level, device tree (more than one possible)
// - node type; internal or leaf
// - age; for mapping trees we can infer a minimum age from the block/time
// values. In addition two similar leaf nodes can be compared by looking
// at the block/time for _specific_ blocks. This means we can define an ordering
// on the ages, but not equality.
// - Device details can be aged based on the last_snapshot_time field.
// Iteration of summary info:
// - constraints propagate both up and down the trees. eg, node 'a' may
// be ambiguous (all internal nodes are ambigous). If we find that all it's
// children are device details trees, then we infer that this is too and lose
// the ambiguity. Now if it has a sibling we can infer on this too.
// - Some characteristics only propagate upwards. eg, age. So we need two monoids
// for summary info (up and down).
namespace {
using namespace std;
using namespace boost;
using namespace persistent_data::btree_detail;
using namespace thin_provisioning::device_tree_detail;
enum btree_type {
TOP_LEVEL,
BOTTOM_LEVEL,
DEVICE_DETAILS
};
struct node_info {
node_info()
: valid(true),
type(TOP_LEVEL),
b(0),
values(0),
key_low(0),
key_high(0),
age(0),
nr_mappings(0) {
}
bool valid;
btree_type type;
block_address b;
unsigned values;
uint64_t key_low;
uint64_t key_high;
//set<uint32_t> devices;
uint32_t age;
map<uint32_t, uint32_t> time_counts;
unsigned nr_mappings;
};
#if SHOW_WORKING
ostream &operator <<(ostream &out, node_info const &n) {
out << "b=" << n.b << ", valid=" << n.valid << ", type=" << n.type << ", values=" << n.values;
out << ", nr_mapped=" << n.nr_mappings;
for (auto const &p : n.time_counts)
out << ", t" << p.first << "=" << p.second;
return out;
}
#endif
bool cmp_time_counts(pair<node_info, node_info> const &lhs_pair,
pair<node_info, node_info> const &rhs_pair) {
auto const &lhs = lhs_pair.first.time_counts;
auto const &rhs = rhs_pair.first.time_counts;
for (auto lhs_it = lhs.crbegin(); lhs_it != lhs.crend(); lhs_it++) {
for (auto rhs_it = rhs.crbegin(); rhs_it != rhs.crend(); rhs_it++) {
if (lhs_it->first > rhs_it->first)
return true;
else if (rhs_it->first > lhs_it->first)
return false;
else if (lhs_it->second > rhs_it->second)
return true;
else if (rhs_it->second > lhs_it->second)
return false;
}
}
return true;
}
class gatherer {
public:
gatherer(block_manager<> &bm)
: bm_(bm),
referenced_(bm.get_nr_blocks(), false),
examined_(bm.get_nr_blocks(), false) {
}
optional<pair<block_address, block_address>>
find_best_roots(transaction_manager &tm) {
vector<node_info> mapping_roots;
vector<node_info> device_roots;
auto nr_blocks = bm_.get_nr_blocks();
for (block_address b = 0; b < nr_blocks; b++)
get_info(b);
for (block_address b = 0; b < nr_blocks; b++) {
if (referenced(b))
continue;
auto info = get_info(b);
if (info.valid) {
if (info.type == TOP_LEVEL)
mapping_roots.push_back(info);
else if (info.type == DEVICE_DETAILS)
device_roots.push_back(info);
}
}
#if SHOW_WORKING
cerr << "mapping candidates (" << mapping_roots.size() << "):\n";
for (auto const &i : mapping_roots)
cerr << i << "\n";
cerr << "\ndevice candidates (" << device_roots.size() << "):\n";
for (auto const &i : device_roots)
cerr << i << "\n";
#endif
auto pairs = find_compatible_roots(tm, device_roots, mapping_roots);
#if SHOW_WORKING
for (auto const &p : pairs)
cerr << "(" << p.first << ", " << p.second << ")\n";
#endif
if (pairs.size())
return pairs[0];
else
return optional<pair<block_address, block_address>>();
}
private:
bool set_eq(set<uint32_t> const &lhs, set<uint32_t> const &rhs) {
for (auto v : lhs)
if (!rhs.count(v))
return false;
return true;
}
vector<pair<block_address, block_address> >
find_compatible_roots(transaction_manager &tm,
vector<node_info> const &device_roots,
vector<node_info> const &mapping_roots) {
vector<pair<node_info, node_info>> pairs;
set<block_address> d_roots;
set<block_address> m_roots;
// construct pairs that have the same number of entries
for (auto const &di : device_roots)
for (auto const &mi : mapping_roots)
if (di.values == mi.values && di.nr_mappings == mi.nr_mappings) {
pairs.push_back(make_pair(di, mi));
d_roots.insert(di.b);
m_roots.insert(mi.b);
}
sort(pairs.begin(), pairs.end(), cmp_time_counts);
map<block_address, set<uint32_t>> ds;
for (auto b : d_roots)
ds.insert(make_pair(b, get_dev_ids(tm, b)));
map<block_address, set<uint32_t>> ms;
for (auto b : m_roots)
ms.insert(make_pair(b, get_map_ids(tm, b)));
// now we check that the thin_ids are identical
vector<pair<block_address, block_address>> filtered;
for (auto const &p : pairs) {
auto lhs = ds.find(p.first.b);
if (lhs == ds.end())
continue;
auto rhs = ms.find(p.second.b);
if (rhs == ms.end())
continue;
filtered.push_back(make_pair(p.first.b, p.second.b));
}
return filtered;
}
void mark_referenced(block_address b) {
referenced_[b] = true;
}
bool referenced(block_address b) const {
return referenced_[b];
}
bool is_btree_node(block_address b) {
auto v = create_btree_node_validator();
auto rr = bm_.read_lock(b);
return v->check_raw(rr.data());
}
// The bottom layer has the block time encoded in it, with the time
// in the bottom 24 bits. This means every block/time apart from block 0
// will result in a value that's outside the range of the metadata device.
bool is_top_level(node_ref<uint64_traits> &n) {
auto nr_metadata_blocks = bm_.get_nr_blocks();
for (unsigned i = 0; i < n.get_nr_entries(); i++)
if (n.value_at(i) >= nr_metadata_blocks)
return false;
return true;
}
uint32_t get_dd_age(device_details const &dd) {
return max(dd.creation_time_, dd.snapshotted_time_);
}
void fail(node_info &n, const char *reason) {
// cerr << n.b << " failed: " << reason << "\n";
n.valid = false;
}
bool failed(node_info const &n) {
return !n.valid;
}
void inc_time_count(map<uint32_t, uint32_t> &counts, uint32_t time) {
auto it = counts.find(time);
if (it == counts.end()) {
counts.insert(make_pair(time, 1));
} else
it->second++;
}
void merge_time_counts(map<uint32_t, uint32_t> &lhs, map<uint32_t, uint32_t> const &rhs) {
for (auto const &p : rhs) {
auto it = lhs.find(p.first);
if (it == lhs.end())
lhs.insert(p);
else
it->second += p.second;
}
}
node_info get_internal_info(block_manager<>::read_ref &rr) {
node_info info;
info.b = rr.get_location();
// values refer to blocks, so we should have infos for them.
auto n = to_node<block_traits>(rr);
uint64_t key_low = 0;
unsigned values = 0;
for (unsigned i = 0; i < n.get_nr_entries(); i++) {
auto child = get_info(n.value_at(i));
if (failed(child)) {
fail(info, "child failed");
break;
}
if (!i)
info.type = child.type;
else if (info.type != child.type) {
fail(info, "mismatch types");
break;
}
// we use the keys to help decide if this is a valid child
if (key_low && child.key_low <= key_low) {
fail(info, "bad keys");
break;
} else
key_low = child.key_high;
values += child.values;
merge_time_counts(info.time_counts, child.time_counts);
info.age = max(info.age, child.age);
info.nr_mappings += child.nr_mappings;
}
// We don't clear the orphan flags until we know the parent is good
if (!failed(info)) {
info.values = values;
for (unsigned i = 0; i < n.get_nr_entries(); i++)
mark_referenced(n.value_at(i));
}
return info;
}
node_info get_leaf_info(block_manager<>::read_ref &rr, node_header const &hdr) {
node_info info;
info.b = rr.get_location();
auto vsize = to_cpu<uint32_t>(hdr.value_size);
info.values = to_cpu<uint32_t>(hdr.nr_entries);
if (vsize == sizeof(device_details_traits::disk_type)) {
auto n = to_node<device_details_traits>(rr);
info.type = DEVICE_DETAILS;
if (n.get_nr_entries()) {
info.key_low = n.key_at(0);
info.key_high = n.key_at(n.get_nr_entries() - 1);
}
for (unsigned i = 0; i < n.get_nr_entries(); i++) {
info.age = max(info.age, get_dd_age(n.value_at(i)));
info.nr_mappings += n.value_at(i).mapped_blocks_;
}
} else if (vsize == sizeof(uint64_t)) {
auto n = to_node<uint64_traits>(rr);
if (n.get_nr_entries()) {
info.key_low = n.key_at(0);
info.key_high = n.key_at(n.get_nr_entries() - 1);
}
if (is_top_level(n)) {
info.type = TOP_LEVEL;
for (unsigned i = 0; i < n.get_nr_entries(); i++) {
node_info child = get_info(n.value_at(i));
if (!child.valid || (child.type != BOTTOM_LEVEL)) {
fail(info, "child not bottom level");
return info;
}
info.age = max(info.age, child.age);
merge_time_counts(info.time_counts, child.time_counts);
info.nr_mappings += child.nr_mappings;
}
for (unsigned i = 0; i < n.get_nr_entries(); i++)
mark_referenced(n.value_at(i));
} else {
auto n = to_node<mapping_tree_detail::block_traits>(rr);
info.type = BOTTOM_LEVEL;
for (unsigned i = 0; i < n.get_nr_entries(); i++) {
auto bt = n.value_at(i);
inc_time_count(info.time_counts, bt.time_);
info.age = max(info.age, bt.time_);
}
info.nr_mappings = n.get_nr_entries();
}
}
return info;
}
node_info get_info_(block_address b) {
if (!is_btree_node(b)) {
node_info info;
info.b = b;
fail(info, "not btree node");
return info;
}
auto rr = bm_.read_lock(b);
auto hdr = reinterpret_cast<node_header const *>(rr.data());
auto flags = to_cpu<uint32_t>(hdr->flags);
if (flags & INTERNAL_NODE)
return get_internal_info(rr);
else
return get_leaf_info(rr, *hdr);
}
node_info get_info(block_address b) {
if (examined_[b]) {
auto it = infos_.find(b);
if (it == infos_.end()) {
node_info info;
info.b = b;
fail(info, "unknown");
return info;
}
return it->second;
} else {
node_info info = get_info_(b);
examined_[b] = true;
if (!failed(info))
infos_.insert(make_pair(b, info));
return info;
}
}
block_manager<> &bm_;
vector<bool> referenced_;
vector<bool> examined_;
map<block_address, node_info> infos_;
};
}
//----------------------------------------------------------------
namespace {
class mapping_emitter : public mapping_tree_detail::mapping_visitor {
public:
mapping_emitter(emitter::ptr e)
@ -551,7 +684,7 @@ namespace {
}
e_->end_device();
} else if (!opts_.repair_) {
} else {
ostringstream msg;
msg << "mappings present for device " << dev_id
<< ", but it isn't present in device tree";
@ -593,10 +726,8 @@ namespace {
void
thin_provisioning::metadata_dump(metadata::ptr md, emitter::ptr e, dump_options const &opts)
{
find_best_roots(*md->tm_->get_bm());
details_extractor de(opts);
device_tree_detail::damage_visitor::ptr dd_policy(details_damage_policy(opts.repair_));
device_tree_detail::damage_visitor::ptr dd_policy(details_damage_policy(false));
walk_device_tree(*md->details_, de, *dd_policy);
e->begin_superblock("", md->sb_.time_,
@ -608,8 +739,67 @@ thin_provisioning::metadata_dump(metadata::ptr md, emitter::ptr e, dump_options
boost::optional<block_address>());
{
mapping_tree_detail::damage_visitor::ptr md_policy(mapping_damage_policy(opts.repair_));
mapping_tree_emitter mte(opts, md, e, de.get_details(), mapping_damage_policy(opts.repair_));
mapping_tree_detail::damage_visitor::ptr md_policy(mapping_damage_policy(false));
mapping_tree_emitter mte(opts, md, e, de.get_details(), mapping_damage_policy(false));
walk_mapping_tree(*md->mappings_top_level_, mte, *md_policy);
}
e->end_superblock();
}
void
thin_provisioning::metadata_repair(block_manager<>::ptr bm, emitter::ptr e)
{
// We assume the superblock is wrong, and find the best roots
// for ourselves. We've had a few cases where people have
// activated a pool on multiple hosts at once, which results in
// the superblock being over written.
gatherer g(*bm);
auto tm = open_tm(bm, superblock_detail::SUPERBLOCK_LOCATION);
auto p = g.find_best_roots(*tm);
metadata::ptr md;
if (p) {
// We found good roots, so we fill out our own superblock,
// with some help from the old sb.
// FIXME: what happens if the superblock can't be read?
// catch and fill out defaults? what should the data_block_size be?
auto sb = read_superblock(*bm);
sb.metadata_snap_ = 0;
sb.device_details_root_ = p->first;
sb.data_mapping_root_ = p->second;
sb.metadata_nr_blocks_ = bm->get_nr_blocks();
md.reset(new metadata(bm, sb));
} else {
// We couldn't find any good roots, so we'll fall back to using the
// on disk superblock.
md.reset(new metadata(bm, false));
}
dump_options opts;
details_extractor de(opts);
device_tree_detail::damage_visitor::ptr dd_policy(details_damage_policy(false));
walk_device_tree(*md->details_, de, *dd_policy);
e->begin_superblock("", md->sb_.time_,
md->sb_.trans_id_,
md->sb_.flags_,
md->sb_.version_,
md->sb_.data_block_size_,
get_nr_blocks(md),
boost::optional<block_address>());
{
mapping_tree_detail::damage_visitor::ptr md_policy(mapping_damage_policy(false));
mapping_tree_emitter mte(opts, md, e, de.get_details(), mapping_damage_policy(false));
walk_mapping_tree(*md->mappings_top_level_, mte, *md_policy);
}

12
thin-provisioning/metadata_dumper.h
View File

@ -31,8 +31,7 @@ namespace thin_provisioning {
class dump_options {
public:
dump_options()
: repair_(false),
skip_mappings_(false) {
: skip_mappings_(false) {
}
bool selected_dev(uint64_t dev_id) const {
@ -46,11 +45,11 @@ namespace thin_provisioning {
dev_filter_->insert(dev_id);
}
bool repair_;
bool skip_mappings_;
using dev_set = std::set<uint64_t>;
using maybe_dev_set = boost::optional<dev_set>;
maybe_dev_set dev_filter_;
};
@ -58,6 +57,13 @@ namespace thin_provisioning {
// the dumper to do it's best to recover info. If not set, any
// corruption encountered will cause an exception to be thrown.
void metadata_dump(metadata::ptr md, emitter::ptr e, dump_options const &opts);
// We have to provide a different interface for repairing, since
// the superblock itself may be corrupt, so we wont be able
// to create the metadata object.
void metadata_repair(block_manager<>::ptr bm, emitter::ptr e);
// Only used by ll_restore, so we leave the repair arg
void metadata_dump_subtree(metadata::ptr md, emitter::ptr e, bool repair, uint64_t subtree_root);
}

12
thin-provisioning/thin_dump.cc
View File

@ -40,12 +40,14 @@ namespace {
struct flags {
flags()
: format("xml"),
repair(false),
use_metadata_snap(false) {
}
dump_options opts;
string format;
bool repair;
bool use_metadata_snap;
optional<block_address> snap_location;
};
@ -84,9 +86,15 @@ namespace {
int dump_(string const &path, ostream &out, struct flags &flags) {
try {
metadata::ptr md = open_metadata(path, flags);
emitter::ptr e = create_emitter(flags.format, out);
if (flags.repair) {
auto bm = open_bm(path, block_manager<>::READ_ONLY, true);
metadata_repair(bm, e);
} else {
metadata::ptr md = open_metadata(path, flags);
metadata_dump(md, e, flags.opts);
}
} catch (std::exception &e) {
cerr << e.what() << endl;
@ -161,7 +169,7 @@ thin_dump_cmd::run(int argc, char **argv)
break;
case 'r':
flags.opts.repair_ = true;
flags.repair = true;
break;
case 'm':

8
thin-provisioning/thin_repair.cc
View File

@ -22,14 +22,8 @@ namespace {
block_manager<>::ptr new_bm = open_bm(new_path, block_manager<>::READ_WRITE);
metadata::ptr new_md(new metadata(new_bm, metadata::CREATE, 128, 0));
emitter::ptr e = create_restore_emitter(new_md);
block_manager<>::ptr old_bm = open_bm(old_path, block_manager<>::READ_ONLY);
metadata::ptr old_md(new metadata(old_bm, false));
dump_options opts;
opts.repair_ = true;
metadata_dump(old_md, e, opts);
metadata_repair(old_bm, e);
} catch (std::exception &e) {
cerr << e.what() << endl;