Skip stashing source blocks in verify mode
Currently block_image_verify() stashes source blocks to /cache and
in some case triggers I/O errors. To avoid this risk, We create
a map from the hash value to the source blocks' range_set. When
executing stash command in verify mode, source range is saved but block
contents aren't stashed. And load_stash could get its value from
either the stashed file from the previous update, or the contents on
the source partition specified by the saved range.
Bug: 27584487
Bug: 25633753
Change-Id: I775baf4bee55762b6e7b204f8294afc597afd996
diff --git a/updater/blockimg.cpp b/updater/blockimg.cpp
index faa7008..c20bad9 100644
--- a/updater/blockimg.cpp
+++ b/updater/blockimg.cpp
@@ -33,6 +33,7 @@
#include <unistd.h>
#include <fec/io.h>
+#include <map>
#include <memory>
#include <string>
#include <vector>
@@ -67,6 +68,8 @@
std::vector<size_t> pos; // Actual limit is INT_MAX.
};
+static std::map<std::string, RangeSet> stash_map;
+
static void parse_range(const std::string& range_text, RangeSet& rs) {
std::vector<std::string> pieces = android::base::Split(range_text, ",");
@@ -522,8 +525,28 @@
}
}
-static int LoadStash(const std::string& base, const std::string& id, bool verify, size_t* blocks,
- std::vector<uint8_t>& buffer, bool printnoent) {
+static int LoadStash(CommandParameters& params, const std::string& base, const std::string& id,
+ bool verify, size_t* blocks, std::vector<uint8_t>& buffer, bool printnoent) {
+ // In verify mode, if source range_set was saved for the given hash,
+ // check contents in the source blocks first. If the check fails,
+ // search for the stashed files on /cache as usual.
+ if (!params.canwrite) {
+ if (stash_map.find(id) != stash_map.end()) {
+ const RangeSet& src = stash_map[id];
+ allocate(src.size * BLOCKSIZE, buffer);
+
+ if (ReadBlocks(src, buffer, params.fd) == -1) {
+ fprintf(stderr, "failed to read source blocks in stash map.\n");
+ return -1;
+ }
+ if (VerifyBlocks(id, buffer, src.size, true) != 0) {
+ fprintf(stderr, "failed to verify loaded source blocks in stash map.\n");
+ return -1;
+ }
+ return 0;
+ }
+ }
+
if (base.empty()) {
return -1;
}
@@ -722,7 +745,7 @@
const std::string& id = params.tokens[params.cpos++];
size_t blocks = 0;
- if (usehash && LoadStash(base, id, true, &blocks, buffer, false) == 0) {
+ if (usehash && LoadStash(params, base, id, true, &blocks, buffer, false) == 0) {
// Stash file already exists and has expected contents. Do not
// read from source again, as the source may have been already
// overwritten during a previous attempt.
@@ -747,6 +770,12 @@
return 0;
}
+ // In verify mode, save source range_set instead of stashing blocks.
+ if (!params.canwrite && usehash) {
+ stash_map[id] = src;
+ return 0;
+ }
+
fprintf(stderr, "stashing %zu blocks to %s\n", blocks, id.c_str());
return WriteStash(base, id, blocks, buffer, false, nullptr);
}
@@ -857,7 +886,7 @@
}
std::vector<uint8_t> stash;
- int res = LoadStash(stashbase, tokens[0], false, nullptr, stash, true);
+ int res = LoadStash(params, stashbase, tokens[0], false, nullptr, stash, true);
if (res == -1) {
// These source blocks will fail verification if used later, but we
@@ -931,8 +960,9 @@
if (VerifyBlocks(srchash, params.buffer, src_blocks, true) == 0) {
// If source and target blocks overlap, stash the source blocks so we can
- // resume from possible write errors
- if (overlap) {
+ // resume from possible write errors. In verify mode, we can skip stashing
+ // because the source blocks won't be overwritten.
+ if (overlap && params.canwrite) {
fprintf(stderr, "stashing %zu overlapping blocks to %s\n", src_blocks,
srchash.c_str());
@@ -953,7 +983,8 @@
return 0;
}
- if (overlap && LoadStash(params.stashbase, srchash, true, nullptr, params.buffer, true) == 0) {
+ if (overlap && LoadStash(params, params.stashbase, srchash, true, nullptr, params.buffer,
+ true) == 0) {
// Overlapping source blocks were previously stashed, command can proceed.
// We are recovering from an interrupted command, so we don't know if the
// stash can safely be deleted after this command.
@@ -1028,8 +1059,15 @@
return -1;
}
+ const std::string& id = params.tokens[params.cpos++];
+
+ if (!params.canwrite && stash_map.find(id) != stash_map.end()) {
+ stash_map.erase(id);
+ return 0;
+ }
+
if (params.createdstash || params.canwrite) {
- return FreeStash(params.stashbase, params.tokens[params.cpos++]);
+ return FreeStash(params.stashbase, id);
}
return 0;