ocfs2: disable BUG assertions in reading blocks

According to some high-load testing, these two BUG assertions were
encountered, this led system panic.  Actually, there were some
discussions about removing these two BUG() assertions, it would not
bring any side effect.

Then, I did the the following changes,

1) use the existing macro CATCH_BH_JBD_RACES to wrap BUG() in the
   ocfs2_read_blocks_sync function like before.

2) disable the macro CATCH_BH_JBD_RACES in Makefile by default.

Link: http://lkml.kernel.org/r/1466574294-26863-1-git-send-email-ghe@suse.com
Signed-off-by: Gang He <ghe@suse.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 5 insertions, 2 deletions

diff --git a/fs/ocfs2/Makefile b/fs/ocfs2/Makefile
index e27e6527912b..4342c7ee7d20 100644
--- a/fs/ocfs2/Makefile
+++ b/fs/ocfs2/Makefile
@@ -1,7 +1,5 @@
 ccflags-y := -Ifs/ocfs2
 
-ccflags-y += -DCATCH_BH_JBD_RACES
-
 obj-$(CONFIG_OCFS2_FS) +=       \
         ocfs2.o                 \
         ocfs2_stackglue.o
diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c
index fe50ded1b4ce..498641eed2db 100644
--- a/fs/ocfs2/buffer_head_io.c
+++ b/fs/ocfs2/buffer_head_io.c
@@ -139,11 +139,16 @@ int ocfs2_read_blocks_sync(struct ocfs2_super *osb, u64 block,
 
                 lock_buffer(bh);
                 if (buffer_jbd(bh)) {
+#ifdef CATCH_BH_JBD_RACES
                         mlog(ML_ERROR,
                              "block %llu had the JBD bit set "
                              "while I was in lock_buffer!",
                              (unsigned long long)bh->b_blocknr);
                         BUG();
+#else
+                        unlock_buffer(bh);
+                        continue;
+#endif
                 }
 
                 clear_buffer_uptodate(bh);