1 files changed, 68 insertions, 0 deletions
diff --git a/sys-block/blktrace/files/blktrace-1.2.0-overlapping-io-stats.patch b/sys-block/blktrace/files/blktrace-1.2.0-overlapping-io-stats.patch
new file mode 100644
index 000000000000..11c495efbc0c
--- /dev/null
+++ b/sys-block/blktrace/files/blktrace-1.2.0-overlapping-io-stats.patch
@@ -0,0 +1,68 @@
+http://git.kernel.dk/?p=blktrace.git;a=commit;h=8fc451c6b0b9a7db7c376ea6865c35321e561f00
+
+From 8fc451c6b0b9a7db7c376ea6865c35321e561f00 Mon Sep 17 00:00:00 2001
+From: Gwendal Grignou <gwendal@chromium.org>
+Date: Fri, 18 Aug 2017 15:00:22 -0700
+Subject: [PATCH] btt: Fix overlapping IO stats.
+
+Keep scanning the tree for overlapping IO otherwise Q2G and process
+traces will be incorrect.
+
+Let assume we have 2 IOs:
+
+A                                      A+a
+|---------------------------------------|
+       B                B+b
+       |-----------------|
+
+In the red/black tree we have:
+
+                    o -> [A,A+a]
+                   / \
+                left right
+                 /    \
+           [...]o      o -> [B, B+b]
+
+In the current code, if we would not be able to find [B+b] in the tree:
+B is greater than A, so we won't go left
+B+b is smaller than A+a, so we are not going right either.
+
+When we have a [X, X+x] IO to look for:
+We need to check for right when either:
+ X+x >= A+a (for merged IO)
+and
+ X > A (for overlapping IO)
+
+TEST=Check with a trace with overlapping IO: Q2C and Q2G are expected.
+
+Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+---
+ btt/dip_rb.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/btt/dip_rb.c b/btt/dip_rb.c
+index 2aa7ffcc763b..6efef6c03b8f 100644
+--- a/btt/dip_rb.c
++++ b/btt/dip_rb.c
+@@ -57,7 +57,7 @@ struct io *rb_find_sec(struct rb_root *root, __u64 sec)
+ 		__iop = rb_entry(n, struct io, rb_node);
+ 		if (sec < BIT_START(__iop))
+ 			n = n->rb_left;
+-		else if (sec >= BIT_END(__iop))
++		else if (sec > BIT_START(__iop))
+ 			n = n->rb_right;
+ 		else
+ 			return __iop;
+@@ -82,7 +82,7 @@ void rb_foreach(struct rb_node *n, struct io *iop,
+ 		}
+ 		if (iop_s < this_s)
+ 			rb_foreach(n->rb_left, iop, fnc, head);
+-		if (this_e < iop_e)
++		if ((this_e < iop_e) || (this_s < iop_s))
+ 			rb_foreach(n->rb_right, iop, fnc, head);
+ 	}
+ }
+-- 
+2.15.1
+