gfs2: print details on transactions that aren't properly ended

If function gfs2_trans_begin is called with another transaction active
it BUGs out, but it doesn't give any details about the duplicate.
This patch moves function gfs2_print_trans and calls it when this
situation arises for better debugging.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/trans.c

@@ -25,13 +25,28 @@
 #include "util.h"
 #include "trace_gfs2.h"
 
+static void gfs2_print_trans(struct gfs2_sbd *sdp, const struct gfs2_trans *tr)
+{
+	fs_warn(sdp, "Transaction created at: %pSR\n", (void *)tr->tr_ip);
+	fs_warn(sdp, "blocks=%u revokes=%u reserved=%u touched=%u\n",
+		tr->tr_blocks, tr->tr_revokes, tr->tr_reserved,
+		test_bit(TR_TOUCHED, &tr->tr_flags));
+	fs_warn(sdp, "Buf %u/%u Databuf %u/%u Revoke %u/%u\n",
+		tr->tr_num_buf_new, tr->tr_num_buf_rm,
+		tr->tr_num_databuf_new, tr->tr_num_databuf_rm,
+		tr->tr_num_revoke, tr->tr_num_revoke_rm);
+}
+
 int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks,
 		     unsigned int revokes)
 {
 	struct gfs2_trans *tr;
 	int error;
 
-	BUG_ON(current->journal_info);
+	if (current->journal_info) {
+		gfs2_print_trans(sdp, current->journal_info);
+		BUG();
+	}
 	BUG_ON(blocks == 0 && revokes == 0);
 
 	if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
@@ -72,18 +87,6 @@ int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks,
 	return error;
 }
 
-static void gfs2_print_trans(struct gfs2_sbd *sdp, const struct gfs2_trans *tr)
-{
-	fs_warn(sdp, "Transaction created at: %pSR\n", (void *)tr->tr_ip);
-	fs_warn(sdp, "blocks=%u revokes=%u reserved=%u touched=%u\n",
-		tr->tr_blocks, tr->tr_revokes, tr->tr_reserved,
-		test_bit(TR_TOUCHED, &tr->tr_flags));
-	fs_warn(sdp, "Buf %u/%u Databuf %u/%u Revoke %u/%u\n",
-		tr->tr_num_buf_new, tr->tr_num_buf_rm,
-		tr->tr_num_databuf_new, tr->tr_num_databuf_rm,
-		tr->tr_num_revoke, tr->tr_num_revoke_rm);
-}
-
 void gfs2_trans_end(struct gfs2_sbd *sdp)
 {
 	struct gfs2_trans *tr = current->journal_info;