From: Jens Axboe <axboe@wiggum>
Date: Mon, 29 Aug 2005 08:14:11 +0000 (+0200)
Subject: [PATCH] Don't overwrite magic in trace
X-Git-Tag: blktrace-0.99~235
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=66fa7233b208860dae3c4ce7be1f5c1e93078720;p=blktrace.git

[PATCH] Don't overwrite magic in trace

Leave the _dat file traces completely intact, get the CPU number from the
file in blkparse instead. Without this change, it's impossible for other
users to verify the sanity and version of a trace.
---

diff --git a/CHANGELOG b/CHANGELOG
index 2202b6a..8975f71 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,8 +1,11 @@
-20050828:
+20050829:
 	- Improved error handling
 	- Remove _dat files, include the payload in _out
 	- Support for payload > 64 bytes
 	- Add install target
+	- Fix RELAYFS Kconfig selection (kernel patch)
+	- blktrace: Don't touch the stored trace, leave magic and version
+	  for blkparse to see as well.
 20050827:
 	- Various cleanups and killing unused variables
 20050826:
diff --git a/blkparse.c b/blkparse.c
index 342f5f6..9f60dcf 100644
--- a/blkparse.c
+++ b/blkparse.c
@@ -28,6 +28,7 @@ static struct rb_root rb_root;
 
 struct trace {
 	struct blk_io_trace *bit;
+	unsigned int cpu;
 	struct rb_node rb_node;
 };
 
@@ -290,7 +291,22 @@ static inline int trace_rb_insert(struct trace *t)
 	return 0;
 }
 
-static int sort_entries(void *traces, unsigned long offset)
+static inline int verify_trace(struct blk_io_trace *t)
+{
+	if (!CHECK_MAGIC(t)) {
+		fprintf(stderr, "bad trace magic %x\n", t->magic);
+		return 1;
+	}
+	if ((t->magic & 0xff) != SUPPORTED_VERSION) {
+		fprintf(stderr, "unsupported trace version %x\n", 
+			t->magic & 0xff);
+		return 1;
+	}
+
+	return 0;
+}
+
+static int sort_entries(void *traces, unsigned long offset, int cpu)
 {
 	struct blk_io_trace *bit;
 	struct trace *t;
@@ -303,8 +319,12 @@ static int sort_entries(void *traces, unsigned long offset)
 		bit = traces;
 		t = malloc(sizeof(*t));
 		t->bit = bit;
+		t->cpu = cpu;
 		memset(&t->rb_node, 0, sizeof(t->rb_node));
 
+		if (verify_trace(bit))
+			break;
+
 		if (trace_rb_insert(t))
 			return -1;
 
@@ -330,7 +350,7 @@ static void show_entries(void)
 		t = rb_entry(n, struct trace, rb_node);
 		bit = t->bit;
 
-		cpu = bit->magic;
+		cpu = t->cpu;
 		if (cpu > max_cpus) {
 			fprintf(stderr, "CPU number too large (%d)\n", cpu);
 			break;
@@ -400,7 +420,7 @@ int main(int argc, char *argv[])
 			break;
 		}
 
-		ret = sort_entries(tb, st.st_size);
+		ret = sort_entries(tb, st.st_size, i);
 		if (ret == -1)
 			break;
 
diff --git a/blktrace.c b/blktrace.c
index 58ae222..1064bd4 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -176,8 +176,6 @@ static void *extract(void *arg)
 		if (verify_trace(&t))
 			exit(1);
 
-		/* version is verified, stuff with CPU number now */
-		t.magic = tip->cpu;
 		ret = write(ofd, &t, sizeof(t));
 		if (ret < 0) {
 			perror(op);