From 9bf6fbce6dfccd16bb54a9801ca287bac6950a09 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Fri, 14 Apr 2023 17:10:02 +0200
Subject: [FUSE] cow: More fixes and refactoring

Don't allocate a data cluster in data file for empty l2 entries when
resizing the image file.
Calculating l2 offset in metadata file was broken and overlapping l1.
Delete unneeded entries from cow struct.
Rename a few more variables.
Fix a few possible race conditions.
Only upload modified blocks from cluster.
Simplify cow_write() function by handling misaligned start/end first.
Try to also simplify cow_read() a bit.

TODO: Documentation, update the cow merger service.
---
 src/cowtest/main.c | 50 +++++++++++++++++++++++++++++++++++---------------
 1 file changed, 35 insertions(+), 15 deletions(-)

(limited to 'src/cowtest')

diff --git a/src/cowtest/main.c b/src/cowtest/main.c
index 38d0f16..c7da4ac 100644
--- a/src/cowtest/main.c
+++ b/src/cowtest/main.c
@@ -43,7 +43,7 @@ atomic_bool randomTestLoop = true;
 
 #define RND_MAX_WRITE_SIZE 4096 * 320
 #define RND_TRUNCATE_PROBABILITY 5
-#define RND_UNALIGNED_WRITE_PROBABILITY 5
+#define RND_UNALIGNED_WRITE_PROBABILITY 80
 #define RND_DEFAULT_MIN_SIZE_PERCENT 0.9f
 #define RND_DEFAULT_MAX_SIZE_PERCENT 1.1f
 #define BASE_DATA (char)42
@@ -97,10 +97,29 @@ bool generateTestFile( char *path, size_t size )
  * @param str 
  * @param len 
  */
-void printCharInHexadecimal( const char *str, int len )
+void printCharInHexadecimal( const char *str, const char *got, int len )
 {
+	int pr = 0;
 	for ( int i = 0; i < len; ++i ) {
-		printf( "0x%02x ", (int)str[i] );
+		if ( pr > 0 ) {
+			pr--;
+			if ( str[i] != got[i] ) {
+				printf( "[%02x/%02x] ", (int)str[i], (int)got[i] );
+			} else {
+				printf( "%02x ", (int)str[i] );
+			}
+			if ( pr == 0 ) {
+				printf( " .." );
+			}
+		} else {
+			if ( str[i] != got[i] ) {
+				pr = 4;
+				i = MAX( -1, i - 4 );
+				if ( i != -1 ) {
+					printf(".. " );
+				}
+			}
+		}
 	}
 	printf( "\n" );
 }
@@ -118,12 +137,10 @@ void printCharInHexadecimal( const char *str, int len )
 bool compare( char buff[], char expected[], size_t size, char errorMessage[] )
 {
 	if ( memcmp( buff, expected, size ) != 0 ) {
-		printf( "%s", errorMessage );
+		printf( "%s\n", errorMessage );
 		if ( printOnError ) {
-			printf( "Expected: \n" );
-			printCharInHexadecimal( expected, (int)size );
-			printf( "Got: \n " );
-			printCharInHexadecimal( buff, (int)size );
+			printf( "Diff [want/got]: \n" );
+			printCharInHexadecimal( expected, buff, (int)size );
 		}
 		return false;
 	}
@@ -247,14 +264,14 @@ bool verifySingleBit()
 	expected[0] = 1;
 	if ( !readSizeTested( fh, buff, DNBD3_BLOCK_SIZE, 0, "SingleBit test Failed: first read to small" ) )
 		return false;
-	if ( !compare( buff, expected, DNBD3_BLOCK_SIZE, "SingleBit test Failed: first write not as expected" ) )
+	if ( !compare( buff, expected, DNBD3_BLOCK_SIZE, "SingleBit test Failed: first read not as expected" ) )
 		return false;
 
 	expected[0] = BASE_DATA;
 	expected[DNBD3_BLOCK_SIZE / 2] = 1;
 	if ( !readSizeTested( fh, buff, DNBD3_BLOCK_SIZE, DNBD3_BLOCK_SIZE, "SingleBit test Failed: second read to small" ) )
 		return false;
-	if ( !compare( buff, expected, DNBD3_BLOCK_SIZE, "SingleBit test Failed: second write not as expected" ) )
+	if ( !compare( buff, expected, DNBD3_BLOCK_SIZE, "SingleBit test Failed: second read not as expected" ) )
 		return false;
 	printf( "testSingleBit successful!\n" );
 	return true;
@@ -426,7 +443,7 @@ bool verifyLongNonAlignedPattern()
 		if ( !readSizeTested( fh, buffer, sizeToRead, offset, "writeLongNonAlignedPattern test Failed: read failed" ) ) {
 			return false;
 		}
-		if ( !compare( buffer, expected, sizeToRead, "writeLongNonAlignedPattern test Failed:  read failed" ) )
+		if ( !compare( buffer, expected, sizeToRead, "writeLongNonAlignedPattern test Failed: compare failed" ) )
 			return false;
 		offset += sizeToRead;
 	}
@@ -755,7 +772,7 @@ bool verifyFinalFile( char *path )
 
 	size_t fileSize = testFileSize + 2 * l2Capacity;
 	struct stat st;
-	stat( path, &st );
+	fstat( fh, &st );
 	size_t size = st.st_size;
 	if ( size != fileSize ) {
 		printf( "verify Failed, wrong file size\n expectedSize: %zu\n got: %zu\n", fileSize, size );
@@ -1023,7 +1040,7 @@ bool randomWriteTest( char *mountedImagePath,  char *normalImagePath, float minS
 		return (void*) false;
 	}
 	// RANDOM WRITE LOOP
-	printf( "Press any key to cancel\n" );
+	printf( "Press Ctrl-C to stop and compare\n" );
 	while ( randomTestLoop ) {
 		//select test
 		int r = rand() % 100;
@@ -1042,7 +1059,10 @@ bool randomWriteTest( char *mountedImagePath,  char *normalImagePath, float minS
 		} else {
 			// write test
 			off_t offset = rand() % maxOffset;
-			size_t size = rand() % RND_MAX_WRITE_SIZE;
+			size_t size = ( rand() + offset ) % RND_MAX_WRITE_SIZE;
+			if ( size < RND_MAX_WRITE_SIZE / 2 ) {
+				size /= rand() % 8192;
+			}
 			size = MAX( size, 1 );
 			if ( r > RND_TRUNCATE_PROBABILITY + RND_UNALIGNED_WRITE_PROBABILITY ) {
 				// align to block
@@ -1051,7 +1071,7 @@ bool randomWriteTest( char *mountedImagePath,  char *normalImagePath, float minS
 			}
 
 			generateRandomData( fhr, buf, size );
-			printf( "write offset: %zu size: %zu\n", offset, size );
+			printf( "write offset: %zu size: %zu r: %d\n", offset, size, r );
 			if ( !writeSizeTested( fhm, buf, size, offset, "failed to write on mounted image" ) )
 				return false;
 			if ( !writeSizeTested( fhn, buf, size, offset, "failed to write on normal image" ) )
-- 
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