Merge pull request #9384 from davidsaada/david_mbr_erase_start

MBRBlockDevice: When partitioning, clear the rest of first erase unit
ARMmbed · Jan 16, 2019 · a2220f3 · a2220f3
1 parent 5e0a2d9
commit a2220f3
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Showing 2 changed files with 72 additions and 2 deletions.
diff --git a/features/storage/TESTS/filesystem/multipart_fat_filesystem/main.cpp b/features/storage/TESTS/filesystem/multipart_fat_filesystem/main.cpp
@@ -21,6 +21,7 @@
 #include "HeapBlockDevice.h"
 #include "FATFileSystem.h"
 #include "MBRBlockDevice.h"
+#include "LittleFileSystem.h"
 #include <stdlib.h>
 #include "mbed_retarget.h"
 
@@ -221,9 +222,66 @@ void test_single_mbr()
  TEST_ASSERT_EQUAL(0, err);
 
  delete bd;
- bd = 0;
 }
 
+void test_with_other_fs()
+{
+ TEST_SKIP_UNLESS_MESSAGE(bd, "Not enough heap memory to run test. Test skipped.");
+
+ // Stage 0 - LittleFS
+ // Stage 1 - FatFS with MBR
+ // Stage 2 - LittleFS
+ // Make sure that at no stage we are able to mount the current file system after using the
+ // previous one
+
+ // start from scratch in this test
+ bd = new (std::nothrow) HeapBlockDevice(BLOCK_COUNT * BLOCK_SIZE, BLOCK_SIZE);
+ TEST_SKIP_UNLESS_MESSAGE(bd, "Not enough heap memory to run test. Test skipped.");
+
+ int err;
+
+ for (int stage = 0; stage < 3; stage++) {
+
+ BlockDevice *part;
+ FileSystem *fs;
+
+ if (stage == 1) {
+ printf("Stage %d: FAT FS\n", stage + 1);
+ err = MBRBlockDevice::partition(bd, 1, 0x83, 0, BLOCK_COUNT * BLOCK_SIZE);
+ TEST_ASSERT_EQUAL(0, err);
+
+ part = new (std::nothrow) MBRBlockDevice(bd, 1);
+ TEST_SKIP_UNLESS_MESSAGE(part, "Not enough heap memory to run test. Test skipped.");
+
+ err = part->init();
+ TEST_ASSERT_EQUAL(0, err);
+
+ fs = new FATFileSystem("fat");
+ } else {
+ printf("Stage %d: Little FS\n", stage + 1);
+ part = bd;
+ fs = new LittleFileSystem("lfs");
+ }
+ TEST_SKIP_UNLESS_MESSAGE(fs, "Not enough heap memory to run test. Test skipped.");
+
+ err = fs->mount(part);
+ TEST_ASSERT_NOT_EQUAL(0, err);
+
+ err = fs->reformat(part);
+ TEST_ASSERT_EQUAL(0, err);
+
+ err = fs->unmount();
+ TEST_ASSERT_EQUAL(0, err);
+
+ delete fs;
+ if (stage == 1) {
+ delete part;
+ }
+ }
+
+ delete bd;
+ bd = 0;
+}
 
 // Test setup
 utest::v1::status_t test_setup(const size_t number_of_cases)
@@ -237,6 +295,7 @@ Case cases[] = {
  Case("Testing read write < block", test_read_write < BLOCK_SIZE / 2 >),
  Case("Testing read write > block", test_read_write<2 * BLOCK_SIZE>),
  Case("Testing for no extra MBRs", test_single_mbr),
+ Case("Testing with other file system", test_with_other_fs),
 };
 
 Specification specification(test_setup, cases);

diff --git a/features/storage/blockdevice/MBRBlockDevice.cpp b/features/storage/blockdevice/MBRBlockDevice.cpp
@@ -92,8 +92,9 @@ static int partition_absolute(
  return err;
  }
 
+ uint32_t table_start_offset = buffer_size - sizeof(struct mbr_table);
  struct mbr_table *table = reinterpret_cast<struct mbr_table *>(
- &buffer[buffer_size - sizeof(struct mbr_table)]);
+  &buffer[table_start_offset]);
  if (table->signature[0] != 0x55 || table->signature[1] != 0xaa) {
  // Setup default values for MBR
  table->signature[0] = 0x55;
@@ -143,6 +144,16 @@ static int partition_absolute(
  }
  }
 
+ // As the erase operation may do nothing, erase remainder of the buffer, to eradicate
+ // any remaining programmed data (such as previously programmed file systems).
+ if (table_start_offset > 0) {
+ memset(buffer, 0xFF, table_start_offset);
+ }
+ if (table_start_offset + sizeof(struct mbr_table) < buffer_size) {
+ memset(buffer + table_start_offset + sizeof(struct mbr_table), 0xFF,
+ buffer_size - (table_start_offset + sizeof(struct mbr_table)));
+ }
+
  // Write out MBR
  err = bd->erase(0, bd->get_erase_size());
  if (err) {