[PATCH 2/4] xfstests: fsx fallocate support is b0rked

[Dave Chinner]

From: Dave Chinner <dchinner at redhat.com>

The recent fallocate/fpunch additions to fsx have not actually be
executing fallocate/fpunch operations. The logic to select what
operation to run is broken in such a way that fsx has been executing
mapped writes and truncates instead of fallocate and fpunch
operations.

Remove all the (b0rken) smarty-pants selection logic from the test()
function. Replace it with a clearly defined set of operations for
each mode and use understandable fallback logic when various
operation types have been disabled. Then use a simple switch
statement to execute each of the different operations, removing the
tortured nesting of if/else statements that only serve to obfuscate
the code.

NAs a result, fsx uses fallocate/fpunch appropriately during
operations, and uses/disableѕ the operations as defined on the
command line correctly.

Signed-off-by: Dave Chinner <dchinner at redhat.com>
---
 ltp/fsx.c |  162 +++++++++++++++++++++++++++++++++++++++----------------------
 1 files changed, 103 insertions(+), 59 deletions(-)

diff --git a/ltp/fsx.c b/ltp/fsx.c
index a37e223..66daefe 100644
--- a/ltp/fsx.c
+++ b/ltp/fsx.c
@@ -955,18 +955,42 @@ docloseopen(void)
 	}
 }
 
+#define TRIM_OFF_LEN(off, len, size)	\
+do {					\
+	if (file_size)			\
+		offset %= size;		\
+	else				\
+		offset = 0;		\
+	if (offset + len > size)	\
+		len = size - offset;	\
+} while (0)
 
+/*
+ * The operation matrix is complex due to conditional variables.
+ * We calculate how many different operations we can use, then
+ * map them appropriately according to how many options are enabled.
+ * The mapping is:
+ *
+ *		lite	!lite
+ * READ:	0	0
+ * WRITE:	1	1
+ * MAPREAD:	2	2
+ * MAPWRITE:	3	3
+ * TRUNCATE:	-	4
+ * FALLOCATE:	-	5
+ * PUNCH HOLE:	-	6
+ *
+ * When mapped read/writes are disabled, they are simply converted to normal
+ * reads and writes. When fallocate/fpunch calls are disabled, they are
+ * converted to OP_SKIPPED.
+ */
 void
 test(void)
 {
 	unsigned long	offset;
 	unsigned long	size = maxoplen;
 	unsigned long	rv = random();
-	unsigned long	op = rv % (3 + !lite + mapped_writes + fallocate_calls + punch_hole_calls);
-        /* turn off the map read if necessary */
-
-        if (op == 2 && !mapped_reads)
-            op = 0;
+	unsigned long	op;
 
 	if (simulatedopcount > 0 && testcalls == simulatedopcount)
 		writefileimage();
@@ -982,62 +1006,82 @@ test(void)
 	if (!quiet && testcalls < simulatedopcount && testcalls % 100000 == 0)
 		prt("%lu...\n", testcalls);
 
-	/*
-	 *                 lite  !lite
-	 * READ:	op = 0	   0
-	 * WRITE:	op = 1     1
-	 * MAPREAD:     op = 2     2
-	 * TRUNCATE:	op = -     3
-	 * MAPWRITE:    op = 3     4
-	 * FALLOCATE:   op = -     5
-	 * PUNCH HOLE:  op = -     6
-	 */
-	if (lite ? 0 : op == 3 && (style & 1) == 0) /* vanilla truncate? */
-		dotruncate(random() % maxfilelen);
-	else {
-		if (randomoplen)
-			size = random() % (maxoplen+1);
-
-		if (lite ? 0 : op == 3) {
-			/* truncate */
-			dotruncate(size);
-		} else {
-			offset = random();
-			if (op == 5) {
-				/* fallocate */
-				offset %= maxfilelen;
-				if (offset + size > maxfilelen)
-					size = maxfilelen - offset;
-				do_preallocate(offset, size);
-			} else if (op == 6) {
-				offset %= maxfilelen;
-				if (offset + size > maxfilelen)
-					size = maxfilelen - offset;
-				do_punch_hole(offset, size);
-			} else if (op == 1 || op == (lite ? 3 : 4)) {
-				/* write / mapwrite */
-				offset %= maxfilelen;
-				if (offset + size > maxfilelen)
-					size = maxfilelen - offset;
-				if (op != 1)
-					domapwrite(offset, size);
-				else
-					dowrite(offset, size);
-			} else {
-				/* read / mapread */
-				if (file_size)
-					offset %= file_size;
-				else
-					offset = 0;
-				if (offset + size > file_size)
-					size = file_size - offset;
-				if (op != 0)
-					domapread(offset, size);
-				else
-					doread(offset, size);
-			}
+	offset = random();
+	if (randomoplen)
+		size = random() % (maxoplen + 1);
+
+	/* calculate appropriate op to run */
+	if (lite)
+		op = rv % 4;
+	else
+		op = rv % 7;
+
+	switch (op) {
+	case 2:
+		if (!mapped_reads)
+			op = 0;
+		break;
+	case 3:
+		if (!mapped_writes)
+			op = 1;
+		break;
+	case 5:
+		if (!fallocate_calls) {
+			log4(OP_SKIPPED, OP_FALLOCATE, offset, size);
+			goto out;
+		}
+		break;
+	case 6:
+		if (!punch_hole_calls) {
+			log4(OP_SKIPPED, OP_PUNCH_HOLE, offset, size);
+			goto out;
 		}
+		break;
 	}
+
+	switch (op) {
+	case 0:	/* read */
+		TRIM_OFF_LEN(offset, size, file_size);
+		doread(offset, size);
+		break;
+
+	case 1: /* write */
+		TRIM_OFF_LEN(offset, size, maxfilelen);
+		dowrite(offset, size);
+		break;
+
+	case 2:	/* mapread */
+		TRIM_OFF_LEN(offset, size, maxfilelen);
+		domapread(offset, size);
+		break;
+
+	case 3:	/* mapwrite */
+		TRIM_OFF_LEN(offset, size, maxfilelen);
+		domapwrite(offset, size);
+		break;
+
+	case 4: /* truncate */
+		if (!style)
+			size = random() % maxfilelen;
+		dotruncate(size);
+		break;
+
+	case 5:	/* fallocate */
+		TRIM_OFF_LEN(offset, size, maxfilelen);
+		do_preallocate(offset, size);
+		break;
+
+	case 6:	/* punch */
+		TRIM_OFF_LEN(offset, size, maxfilelen);
+		do_punch_hole(offset, size);
+		break;
+	default:
+		prterr("test: unknown operation");
+		report_failure(42);
+		break;
+	}
+
+out:
 	if (sizechecks && testcalls > simulatedopcount)
 		check_size();
 	if (closeopen)
-- 
1.7.5.1