summaryrefslogtreecommitdiffstats
blob: d3c785d3357764390d642c16d0876b2d721867a6 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "liblp/builder.h"

#if defined(__linux__)
#include <linux/fs.h>
#endif
#include <string.h>
#include <sys/ioctl.h>

#include <algorithm>

#include <android-base/unique_fd.h>
#include <uuid/uuid.h>

#include "liblp/liblp.h"
#include "reader.h"
#include "utility.h"

namespace android {
namespace fs_mgr {

bool GetBlockDeviceInfo(const std::string& block_device, BlockDeviceInfo* device_info) {
#if defined(__linux__)
    android::base::unique_fd fd(open(block_device.c_str(), O_RDONLY));
    if (fd < 0) {
        PERROR << __PRETTY_FUNCTION__ << "open '" << block_device << "' failed";
        return false;
    }
    if (!GetDescriptorSize(fd, &device_info->size)) {
        return false;
    }
    if (ioctl(fd, BLKIOMIN, &device_info->alignment) < 0) {
        PERROR << __PRETTY_FUNCTION__ << "BLKIOMIN failed";
        return false;
    }
    if (ioctl(fd, BLKALIGNOFF, &device_info->alignment_offset) < 0) {
        PERROR << __PRETTY_FUNCTION__ << "BLKIOMIN failed";
        return false;
    }
    return true;
#else
    (void)block_device;
    (void)device_info;
    LERROR << __PRETTY_FUNCTION__ << ": Not supported on this operating system.";
    return false;
#endif
}

void LinearExtent::AddTo(LpMetadata* out) const {
    out->extents.push_back(LpMetadataExtent{num_sectors_, LP_TARGET_TYPE_LINEAR, physical_sector_});
}

void ZeroExtent::AddTo(LpMetadata* out) const {
    out->extents.push_back(LpMetadataExtent{num_sectors_, LP_TARGET_TYPE_ZERO, 0});
}

Partition::Partition(const std::string& name, const std::string& guid, uint32_t attributes)
    : name_(name), guid_(guid), attributes_(attributes), size_(0) {}

void Partition::AddExtent(std::unique_ptr<Extent>&& extent) {
    size_ += extent->num_sectors() * LP_SECTOR_SIZE;
    extents_.push_back(std::move(extent));
}

void Partition::RemoveExtents() {
    size_ = 0;
    extents_.clear();
}

void Partition::ShrinkTo(uint64_t aligned_size) {
    if (aligned_size == 0) {
        RemoveExtents();
        return;
    }

    // Remove or shrink extents of any kind until the total partition size is
    // equal to the requested size.
    uint64_t sectors_to_remove = (size_ - aligned_size) / LP_SECTOR_SIZE;
    while (sectors_to_remove) {
        Extent* extent = extents_.back().get();
        if (extent->num_sectors() > sectors_to_remove) {
            size_ -= sectors_to_remove * LP_SECTOR_SIZE;
            extent->set_num_sectors(extent->num_sectors() - sectors_to_remove);
            break;
        }
        size_ -= (extent->num_sectors() * LP_SECTOR_SIZE);
        sectors_to_remove -= extent->num_sectors();
        extents_.pop_back();
    }
    DCHECK(size_ == aligned_size);
}

std::unique_ptr<MetadataBuilder> MetadataBuilder::New(const std::string& block_device,
                                                      uint32_t slot_number) {
    std::unique_ptr<LpMetadata> metadata = ReadMetadata(block_device.c_str(), slot_number);
    if (!metadata) {
        return nullptr;
    }
    std::unique_ptr<MetadataBuilder> builder = New(*metadata.get());
    if (!builder) {
        return nullptr;
    }
    BlockDeviceInfo device_info;
    if (fs_mgr::GetBlockDeviceInfo(block_device, &device_info)) {
        builder->set_block_device_info(device_info);
    }
    return builder;
}

std::unique_ptr<MetadataBuilder> MetadataBuilder::New(const BlockDeviceInfo& device_info,
                                                      uint32_t metadata_max_size,
                                                      uint32_t metadata_slot_count) {
    std::unique_ptr<MetadataBuilder> builder(new MetadataBuilder());
    if (!builder->Init(device_info, metadata_max_size, metadata_slot_count)) {
        return nullptr;
    }
    return builder;
}

std::unique_ptr<MetadataBuilder> MetadataBuilder::New(const LpMetadata& metadata) {
    std::unique_ptr<MetadataBuilder> builder(new MetadataBuilder());
    if (!builder->Init(metadata)) {
        return nullptr;
    }
    return builder;
}

MetadataBuilder::MetadataBuilder() {
    memset(&geometry_, 0, sizeof(geometry_));
    geometry_.magic = LP_METADATA_GEOMETRY_MAGIC;
    geometry_.struct_size = sizeof(geometry_);

    memset(&header_, 0, sizeof(header_));
    header_.magic = LP_METADATA_HEADER_MAGIC;
    header_.major_version = LP_METADATA_MAJOR_VERSION;
    header_.minor_version = LP_METADATA_MINOR_VERSION;
    header_.header_size = sizeof(header_);
    header_.partitions.entry_size = sizeof(LpMetadataPartition);
    header_.extents.entry_size = sizeof(LpMetadataExtent);
}

bool MetadataBuilder::Init(const LpMetadata& metadata) {
    geometry_ = metadata.geometry;

    for (const auto& partition : metadata.partitions) {
        Partition* builder = AddPartition(GetPartitionName(partition), GetPartitionGuid(partition),
                                          partition.attributes);
        if (!builder) {
            return false;
        }

        for (size_t i = 0; i < partition.num_extents; i++) {
            const LpMetadataExtent& extent = metadata.extents[partition.first_extent_index + i];
            if (extent.target_type == LP_TARGET_TYPE_LINEAR) {
                auto copy = std::make_unique<LinearExtent>(extent.num_sectors, extent.target_data);
                builder->AddExtent(std::move(copy));
            } else if (extent.target_type == LP_TARGET_TYPE_ZERO) {
                auto copy = std::make_unique<ZeroExtent>(extent.num_sectors);
                builder->AddExtent(std::move(copy));
            }
        }
    }

    device_info_.alignment = geometry_.alignment;
    device_info_.alignment_offset = geometry_.alignment_offset;
    return true;
}

bool MetadataBuilder::Init(const BlockDeviceInfo& device_info, uint32_t metadata_max_size,
                           uint32_t metadata_slot_count) {
    if (metadata_max_size < sizeof(LpMetadataHeader)) {
        LERROR << "Invalid metadata maximum size.";
        return false;
    }
    if (metadata_slot_count == 0) {
        LERROR << "Invalid metadata slot count.";
        return false;
    }

    // Align the metadata size up to the nearest sector.
    metadata_max_size = AlignTo(metadata_max_size, LP_SECTOR_SIZE);

    // Check that device properties are sane.
    device_info_ = device_info;
    if (device_info_.size % LP_SECTOR_SIZE != 0) {
        LERROR << "Block device size must be a multiple of 512.";
        return false;
    }
    if (device_info_.alignment_offset % LP_SECTOR_SIZE != 0) {
        LERROR << "Alignment offset is not sector-aligned.";
        return false;
    }
    if (device_info_.alignment % LP_SECTOR_SIZE != 0) {
        LERROR << "Partition alignment is not sector-aligned.";
        return false;
    }
    if (device_info_.alignment_offset > device_info_.alignment) {
        LERROR << "Partition alignment offset is greater than its alignment.";
        return false;
    }

    // We reserve a geometry block (4KB) plus space for each copy of the
    // maximum size of a metadata blob. Then, we double that space since
    // we store a backup copy of everything.
    uint64_t reserved =
            LP_METADATA_GEOMETRY_SIZE + (uint64_t(metadata_max_size) * metadata_slot_count);
    uint64_t total_reserved = reserved * 2;
    if (device_info_.size < total_reserved) {
        LERROR << "Attempting to create metadata on a block device that is too small.";
        return false;
    }

    // Compute the first free sector, factoring in alignment.
    uint64_t free_area = AlignTo(reserved, device_info_.alignment, device_info_.alignment_offset);
    uint64_t first_sector = free_area / LP_SECTOR_SIZE;

    // Compute the last free sector, which is inclusive. We subtract 1 to make
    // sure that logical partitions won't overlap with the same sector as the
    // backup metadata, which could happen if the block device was not aligned
    // to LP_SECTOR_SIZE.
    uint64_t last_sector = ((device_info_.size - reserved) / LP_SECTOR_SIZE) - 1;

    // If this check fails, it means either (1) we did not have free space to
    // allocate a single sector, or (2) we did, but the alignment was high
    // enough to bump the first sector out of range. Either way, we cannot
    // continue.
    if (first_sector > last_sector) {
        LERROR << "Not enough space to allocate any partition tables.";
        return false;
    }

    geometry_.first_logical_sector = first_sector;
    geometry_.last_logical_sector = last_sector;
    geometry_.metadata_max_size = metadata_max_size;
    geometry_.metadata_slot_count = metadata_slot_count;
    geometry_.alignment = device_info_.alignment;
    geometry_.alignment_offset = device_info_.alignment_offset;
    geometry_.block_device_size = device_info_.size;
    return true;
}

Partition* MetadataBuilder::AddPartition(const std::string& name, const std::string& guid,
                                         uint32_t attributes) {
    if (name.empty()) {
        LERROR << "Partition must have a non-empty name.";
        return nullptr;
    }
    if (FindPartition(name)) {
        LERROR << "Attempting to create duplication partition with name: " << name;
        return nullptr;
    }
    partitions_.push_back(std::make_unique<Partition>(name, guid, attributes));
    return partitions_.back().get();
}

Partition* MetadataBuilder::FindPartition(const std::string& name) {
    for (const auto& partition : partitions_) {
        if (partition->name() == name) {
            return partition.get();
        }
    }
    return nullptr;
}

void MetadataBuilder::RemovePartition(const std::string& name) {
    for (auto iter = partitions_.begin(); iter != partitions_.end(); iter++) {
        if ((*iter)->name() == name) {
            partitions_.erase(iter);
            return;
        }
    }
}

bool MetadataBuilder::GrowPartition(Partition* partition, uint64_t aligned_size) {
    // Figure out how much we need to allocate.
    uint64_t space_needed = aligned_size - partition->size();
    uint64_t sectors_needed = space_needed / LP_SECTOR_SIZE;
    DCHECK(sectors_needed * LP_SECTOR_SIZE == space_needed);

    struct Interval {
        uint64_t start;
        uint64_t end;

        Interval(uint64_t start, uint64_t end) : start(start), end(end) {}
        bool operator<(const Interval& other) const { return start < other.start; }
    };

    // Collect all extents in the partition table, then sort them by starting
    // sector.
    std::vector<Interval> extents;
    for (const auto& partition : partitions_) {
        for (const auto& extent : partition->extents()) {
            LinearExtent* linear = extent->AsLinearExtent();
            if (!linear) {
                continue;
            }
            extents.emplace_back(linear->physical_sector(),
                                 linear->physical_sector() + extent->num_sectors());
        }
    }
    std::sort(extents.begin(), extents.end());

    // Convert the extent list into a list of gaps between the extents; i.e.,
    // the list of ranges that are free on the disk.
    std::vector<Interval> free_regions;
    for (size_t i = 1; i < extents.size(); i++) {
        const Interval& previous = extents[i - 1];
        const Interval& current = extents[i];

        uint64_t aligned = AlignSector(previous.end);
        if (aligned >= current.start) {
            // There is no gap between these two extents, try the next one.
            // Note that we check with >= instead of >, since alignment may
            // bump the ending sector past the beginning of the next extent.
            continue;
        }

        // The new interval represents the free space starting at the end of
        // the previous interval, and ending at the start of the next interval.
        free_regions.emplace_back(aligned, current.start);
    }

    // Add a final interval representing the remainder of the free space.
    uint64_t last_free_extent_start =
            extents.empty() ? geometry_.first_logical_sector : extents.back().end;
    last_free_extent_start = AlignSector(last_free_extent_start);
    if (last_free_extent_start <= geometry_.last_logical_sector) {
        free_regions.emplace_back(last_free_extent_start, geometry_.last_logical_sector + 1);
    }

    // Find gaps that we can use for new extents. Note we store new extents in a
    // temporary vector, and only commit them if we are guaranteed enough free
    // space.
    std::vector<std::unique_ptr<LinearExtent>> new_extents;
    for (const auto& region : free_regions) {
        // This gap is enough to hold the remainder of the space requested, so we
        // can allocate what we need and return.
        if (region.end - region.start >= sectors_needed) {
            auto extent = std::make_unique<LinearExtent>(sectors_needed, region.start);
            sectors_needed -= extent->num_sectors();
            new_extents.push_back(std::move(extent));
            break;
        }

        // This gap is not big enough to fit the remainder of the space requested,
        // so consume the whole thing and keep looking for more.
        auto extent = std::make_unique<LinearExtent>(region.end - region.start, region.start);
        sectors_needed -= extent->num_sectors();
        new_extents.push_back(std::move(extent));
    }
    if (sectors_needed) {
        LERROR << "Not enough free space to expand partition: " << partition->name();
        return false;
    }

    for (auto& extent : new_extents) {
        partition->AddExtent(std::move(extent));
    }
    return true;
}

void MetadataBuilder::ShrinkPartition(Partition* partition, uint64_t aligned_size) {
    partition->ShrinkTo(aligned_size);
}

std::unique_ptr<LpMetadata> MetadataBuilder::Export() {
    std::unique_ptr<LpMetadata> metadata = std::make_unique<LpMetadata>();
    metadata->header = header_;
    metadata->geometry = geometry_;

    // Flatten the partition and extent structures into an LpMetadata, which
    // makes it very easy to validate, serialize, or pass on to device-mapper.
    for (const auto& partition : partitions_) {
        LpMetadataPartition part;
        memset(&part, 0, sizeof(part));

        if (partition->name().size() > sizeof(part.name)) {
            LERROR << "Partition name is too long: " << partition->name();
            return nullptr;
        }
        if (partition->attributes() & ~(LP_PARTITION_ATTRIBUTE_MASK)) {
            LERROR << "Partition " << partition->name() << " has unsupported attribute.";
            return nullptr;
        }

        strncpy(part.name, partition->name().c_str(), sizeof(part.name));
        if (uuid_parse(partition->guid().c_str(), part.guid) != 0) {
            LERROR << "Could not parse guid " << partition->guid() << " for partition "
                   << partition->name();
            return nullptr;
        }

        part.first_extent_index = static_cast<uint32_t>(metadata->extents.size());
        part.num_extents = static_cast<uint32_t>(partition->extents().size());
        part.attributes = partition->attributes();

        for (const auto& extent : partition->extents()) {
            extent->AddTo(metadata.get());
        }
        metadata->partitions.push_back(part);
    }

    metadata->header.partitions.num_entries = static_cast<uint32_t>(metadata->partitions.size());
    metadata->header.extents.num_entries = static_cast<uint32_t>(metadata->extents.size());
    return metadata;
}

uint64_t MetadataBuilder::AllocatableSpace() const {
    return (geometry_.last_logical_sector - geometry_.first_logical_sector + 1) * LP_SECTOR_SIZE;
}

uint64_t MetadataBuilder::AlignSector(uint64_t sector) {
    // Note: when reading alignment info from the Kernel, we don't assume it
    // is aligned to the sector size, so we round up to the nearest sector.
    uint64_t lba = sector * LP_SECTOR_SIZE;
    uint64_t aligned = AlignTo(lba, device_info_.alignment, device_info_.alignment_offset);
    return AlignTo(aligned, LP_SECTOR_SIZE) / LP_SECTOR_SIZE;
}

void MetadataBuilder::set_block_device_info(const BlockDeviceInfo& device_info) {
    device_info_.size = device_info.size;

    // The kernel does not guarantee these values are present, so we only
    // replace existing values if the new values are non-zero.
    if (device_info.alignment) {
        device_info_.alignment = device_info.alignment;
    }
    if (device_info.alignment_offset) {
        device_info_.alignment_offset = device_info.alignment_offset;
    }
}

bool MetadataBuilder::ResizePartition(Partition* partition, uint64_t requested_size) {
    // Align the space needed up to the nearest sector.
    uint64_t aligned_size = AlignTo(requested_size, LP_SECTOR_SIZE);

    if (aligned_size > partition->size()) {
        return GrowPartition(partition, aligned_size);
    }
    if (aligned_size < partition->size()) {
        ShrinkPartition(partition, aligned_size);
    }
    return true;
}

}  // namespace fs_mgr
}  // namespace android