udf: Promote some debugging messages to udf_error

If there is a problem with a scratched disc or loader, it's valuable to know
which error occurred.

Convert some debug messages to udf_error, neaten those messages too.
Add the calculated tag checksum and the read checksum to error message.
Make udf_error a public function and move the logging prototypes together.

Original-patch-by: NamJae Jeon <linkinjeon@gmail.com>
Reviewed-by: NamJae Jeon <linkinjeon@gmail.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/udf/misc.c b/fs/udf/misc.c
index 9215700..a85fa7c 100644
--- a/fs/udf/misc.c
+++ b/fs/udf/misc.c
@@ -204,6 +204,7 @@
 {
 	struct tag *tag_p;
 	struct buffer_head *bh = NULL;
+	u8 checksum;
 
 	/* Read the block */
 	if (block == 0xFFFFFFFF)
@@ -211,7 +212,7 @@
 
 	bh = udf_tread(sb, block);
 	if (!bh) {
-		udf_debug("block=%d, location=%d: read failed\n",
+		udf_error(sb, __func__, "read failed, block=%u, location=%d\n",
 			  block, location);
 		return NULL;
 	}
@@ -227,15 +228,19 @@
 	}
 
 	/* Verify the tag checksum */
-	if (udf_tag_checksum(tag_p) != tag_p->tagChecksum) {
-		printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
+	checksum = udf_tag_checksum(tag_p);
+	if (checksum != tag_p->tagChecksum) {
+		udf_error(sb, __func__,
+			  "tag checksum failed, block %u: 0x%02x != 0x%02x\n",
+			  block, checksum, tag_p->tagChecksum);
 		goto error_out;
 	}
 
 	/* Verify the tag version */
 	if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
 	    tag_p->descVersion != cpu_to_le16(0x0003U)) {
-		udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\n",
+		udf_error(sb, __func__,
+			  "tag version 0x%04x != 0x0002 || 0x0003, block %u\n",
 			  le16_to_cpu(tag_p->descVersion), block);
 		goto error_out;
 	}