diff --git a/sys-fs/btrfs-progs/Manifest b/sys-fs/btrfs-progs/Manifest
new file mode 100644
index 0000000..9fb954d
--- /dev/null
+++ b/sys-fs/btrfs-progs/Manifest
@@ -0,0 +1,3 @@
+AUX btrfs-progs-v4.0.1-integer-underflow.patch 467 SHA256 caed7aa6d6b5702d973f8a75d1d868e17ee884fc341717af5e677225a994e8e9 SHA512 cf4d8148e0cdece5dcc246c1c65bcf38224b9579de15612b624f813d8b32791743e40102eb620f23a54bdd2d806b29e92961b6eecc7fd157ddc9a50253bdafce WHIRLPOOL aaacc24c48e37ac05917705b3b2cbc10115c47864632ae49a230c5850e66acae20b54b1d0cfa941d547b3ff0ea73d5e5e5de87a58fa2553189277ed5b799bf39
+DIST btrfs-progs-v4.0.1.tar.xz 1104340 SHA256 2c2e10e79edd16a92effe8619c527fd130bc272fbca67896e1705bb2ec0293cb SHA512 52e5165f2fdd0f27f9c2f099b774523c36ab442948a13ede03736297a139903af4c0c444c77abc14b05f3cf633b006eb9dbc29f2b127858698ee1b6ad517a53f WHIRLPOOL ad8d2280c9205537a1045a835bffb39d73684fea87841215cd0916fdc91285aa299dc5885446b3c3aa50fcc2ab562a4b58a33cc9537ede3f57df4bc566aacb47
+EBUILD btrfs-progs-4.0.1-r1.ebuild 2046 SHA256 ae88e4619c0e22956dd3097a8c771db17d59a638a5bdfc4132d81334d415a0be SHA512 7c6f06c410d12f4d9b339f6e60532dc1d2105b95395c6de7bcb739c692e9ef5c6463fc5ac8bd5acf30d322ac0b7809a07c05244b26ee1a78180588a26dac7f99 WHIRLPOOL 735fe0b2fd581e526ab3c4d46ba383e58bb06490297b5213acf406e02438dda93c90dc3ea0b8ac930ab2dcb205a305e91f8215ec59bf759b53eb77a5f51b8340
diff --git a/sys-fs/btrfs-progs/btrfs-progs-4.0.1.ebuild b/sys-fs/btrfs-progs/btrfs-progs-4.0.1-r1.ebuild
similarity index 96%
rename from sys-fs/btrfs-progs/btrfs-progs-4.0.1.ebuild
rename to sys-fs/btrfs-progs/btrfs-progs-4.0.1-r1.ebuild
index 5e7ad41..8512469 100644
--- a/sys-fs/btrfs-progs/btrfs-progs-4.0.1.ebuild
+++ b/sys-fs/btrfs-progs/btrfs-progs-4.0.1-r1.ebuild
@@ -49,6 +49,8 @@ if [[ ${PV} == 9999 ]]; then
 fi
 
 src_prepare() {
+	epatch "${FILESDIR}/btrfs-progs-v4.0.1-integer-underflow.patch"
+
 	epatch_user
 	if [[ ${PV} == 9999 ]]; then
 		eautoreconf
diff --git a/sys-fs/btrfs-progs/files/btrfs-progs-v4.0.1-integer-underflow.patch b/sys-fs/btrfs-progs/files/btrfs-progs-v4.0.1-integer-underflow.patch
new file mode 100644
index 0000000..46fcd42
--- /dev/null
+++ b/sys-fs/btrfs-progs/files/btrfs-progs-v4.0.1-integer-underflow.patch
@@ -0,0 +1,12 @@
+diff -uri btrfs-progs-v4.0.1.orig/ctree.c btrfs-progs-v4.0.1/ctree.c
+--- btrfs-progs-v4.0.1.orig/ctree.c	2015-06-19 03:43:12.000000000 -0500
++++ btrfs-progs-v4.0.1/ctree.c	2015-06-19 03:43:49.000000000 -0500
+@@ -2588,7 +2588,7 @@
+ 	int ret = 0;
+ 
+ 	nritems = btrfs_header_nritems(parent);
+-	if (slot != nritems -1) {
++	if (slot < nritems -1) {
+ 		memmove_extent_buffer(parent,
+ 			      btrfs_node_key_ptr_offset(slot),
+ 			      btrfs_node_key_ptr_offset(slot + 1),