Merge "Check for COW space before writing to COW"
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/cow_writer.h b/fs_mgr/libsnapshot/include/libsnapshot/cow_writer.h
index b93fd32..a9682a1 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/cow_writer.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/cow_writer.h
@@ -16,6 +16,7 @@
#include <stdint.h>
+#include <cstdint>
#include <memory>
#include <optional>
#include <string>
@@ -150,6 +151,7 @@
bool SetFd(android::base::borrowed_fd fd);
bool Sync();
bool Truncate(off_t length);
+ bool EnsureSpaceAvailable(const uint64_t bytes_needed) const;
private:
android::base::unique_fd owned_fd_;
@@ -165,6 +167,7 @@
bool is_dev_null_ = false;
bool merge_in_progress_ = false;
bool is_block_device_ = false;
+ uint64_t cow_image_size_ = INT64_MAX;
};
} // namespace snapshot
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/cow_writer.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/cow_writer.cpp
index 5f5d1fb..43c17a6 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/cow_writer.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/cow_writer.cpp
@@ -30,9 +30,29 @@
#include <lz4.h>
#include <zlib.h>
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
namespace android {
namespace snapshot {
+namespace {
+std::string GetFdPath(int fd) {
+ const auto fd_path = "/proc/self/fd/" + std::to_string(fd);
+ std::string file_path(512, '\0');
+ const auto err = readlink(fd_path.c_str(), file_path.data(), file_path.size());
+ if (err <= 0) {
+ PLOG(ERROR) << "Failed to determine path for fd " << fd;
+ file_path.clear();
+ } else {
+ file_path.resize(err);
+ }
+ return file_path;
+}
+} // namespace
+
static_assert(sizeof(off_t) == sizeof(uint64_t));
using android::base::borrowed_fd;
@@ -163,12 +183,25 @@
} else {
fd_ = fd;
- struct stat stat;
+ struct stat stat {};
if (fstat(fd.get(), &stat) < 0) {
PLOG(ERROR) << "fstat failed";
return false;
}
+ const auto file_path = GetFdPath(fd.get());
is_block_device_ = S_ISBLK(stat.st_mode);
+ if (is_block_device_) {
+ uint64_t size_in_bytes = 0;
+ if (ioctl(fd.get(), BLKGETSIZE64, &size_in_bytes)) {
+ PLOG(ERROR) << "Failed to get total size for: " << fd.get();
+ return false;
+ }
+ cow_image_size_ = size_in_bytes;
+ LOG(INFO) << "COW image " << file_path << " has size " << size_in_bytes;
+ } else {
+ LOG(INFO) << "COW image " << file_path
+ << " is not a block device, assuming unlimited space.";
+ }
}
return true;
}
@@ -343,7 +376,8 @@
op.data_length = static_cast<uint16_t>(data.size());
if (!WriteOperation(op, data.data(), data.size())) {
- PLOG(ERROR) << "AddRawBlocks: write failed";
+ PLOG(ERROR) << "AddRawBlocks: write failed, bytes requested: " << size
+ << ", bytes written: " << i * header_.block_size;
return false;
}
} else {
@@ -512,12 +546,26 @@
return true;
}
-bool CowWriter::WriteOperation(const CowOperation& op, const void* data, size_t size) {
- if (lseek(fd_.get(), next_op_pos_, SEEK_SET) < 0) {
- PLOG(ERROR) << "lseek failed for writing operation.";
+bool CowWriter::EnsureSpaceAvailable(const uint64_t bytes_needed) const {
+ if (bytes_needed > cow_image_size_) {
+ LOG(ERROR) << "No space left on COW device. Required: " << bytes_needed
+ << ", available: " << cow_image_size_;
+ errno = ENOSPC;
return false;
}
- if (!android::base::WriteFully(fd_, reinterpret_cast<const uint8_t*>(&op), sizeof(op))) {
+ return true;
+}
+
+bool CowWriter::WriteOperation(const CowOperation& op, const void* data, size_t size) {
+ if (!EnsureSpaceAvailable(next_op_pos_ + sizeof(op))) {
+ return false;
+ }
+ if (!EnsureSpaceAvailable(next_data_pos_ + size)) {
+ return false;
+ }
+
+ if (!android::base::WriteFullyAtOffset(fd_, reinterpret_cast<const uint8_t*>(&op), sizeof(op),
+ next_op_pos_)) {
return false;
}
if (data != nullptr && size > 0) {
@@ -542,13 +590,8 @@
next_op_pos_ += sizeof(CowOperation) + GetNextOpOffset(op, header_.cluster_ops);
}
-bool CowWriter::WriteRawData(const void* data, size_t size) {
- if (lseek(fd_.get(), next_data_pos_, SEEK_SET) < 0) {
- PLOG(ERROR) << "lseek failed for writing data.";
- return false;
- }
-
- if (!android::base::WriteFully(fd_, data, size)) {
+bool CowWriter::WriteRawData(const void* data, const size_t size) {
+ if (!android::base::WriteFullyAtOffset(fd_, data, size, next_data_pos_)) {
return false;
}
return true;