1 files changed, 71 insertions, 0 deletions
diff --git a/meta/recipes-devtools/qemu/qemu/0002-file-posix-Do-runtime-check-for-ofd-lock-API.patch b/meta/recipes-devtools/qemu/qemu/0002-file-posix-Do-runtime-check-for-ofd-lock-API.patch
new file mode 100644
index 0000000000..0dacde46d1
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0002-file-posix-Do-runtime-check-for-ofd-lock-API.patch
@@ -0,0 +1,71 @@
+From 2b218f5dbcca5fe728b1852d161d7a21fd02b2f5 Mon Sep 17 00:00:00 2001
+From: Fam Zheng <famz@redhat.com>
+Date: Fri, 11 Aug 2017 19:44:47 +0800
+Subject: [PATCH 2/2] file-posix: Do runtime check for ofd lock API
+
+It is reported that on Windows Subsystem for Linux, ofd operations fail
+with -EINVAL. In other words, QEMU binary built with system headers that
+exports F_OFD_SETLK doesn't necessarily run in an environment that
+actually supports it:
+
+$ qemu-system-aarch64 ... -drive file=test.vhdx,if=none,id=hd0 \
+    -device virtio-blk-pci,drive=hd0
+qemu-system-aarch64: -drive file=test.vhdx,if=none,id=hd0: Failed to unlock byte 100
+qemu-system-aarch64: -drive file=test.vhdx,if=none,id=hd0: Failed to unlock byte 100
+qemu-system-aarch64: -drive file=test.vhdx,if=none,id=hd0: Failed to lock byte 100
+
+As a matter of fact this is not WSL specific. It can happen when running
+a QEMU compiled against a newer glibc on an older kernel, such as in
+a containerized environment.
+
+Let's do a runtime check to cope with that.
+
+Reported-by: Andrew Baumann <Andrew.Baumann@microsoft.com>
+Reviewed-by: Eric Blake <eblake@redhat.com>
+Signed-off-by: Fam Zheng <famz@redhat.com>
+Signed-off-by: Kevin Wolf <kwolf@redhat.com>
+
+Upstream-Status: Backport
+Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
+---
+ block/file-posix.c | 19 ++++++++-----------
+ 1 file changed, 8 insertions(+), 11 deletions(-)
+
+diff --git a/block/file-posix.c b/block/file-posix.c
+index f4de022ae0..cb3bfce147 100644
+--- a/block/file-posix.c
++++ b/block/file-posix.c
+@@ -457,22 +457,19 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
+     switch (locking) {
+     case ON_OFF_AUTO_ON:
+         s->use_lock = true;
+-#ifndef F_OFD_SETLK
+-        fprintf(stderr,
+-                "File lock requested but OFD locking syscall is unavailable, "
+-                "falling back to POSIX file locks.\n"
+-                "Due to the implementation, locks can be lost unexpectedly.\n");
+-#endif
++        if (!qemu_has_ofd_lock()) {
++            fprintf(stderr,
++                    "File lock requested but OFD locking syscall is "
++                    "unavailable, falling back to POSIX file locks.\n"
++                    "Due to the implementation, locks can be lost "
++                    "unexpectedly.\n");
++        }
+         break;
+     case ON_OFF_AUTO_OFF:
+         s->use_lock = false;
+         break;
+     case ON_OFF_AUTO_AUTO:
+-#ifdef F_OFD_SETLK
+-        s->use_lock = true;
+-#else
+-        s->use_lock = false;
+-#endif
++        s->use_lock = qemu_has_ofd_lock();
+         break;
+     default:
+         abort();
+-- 
+2.11.0
+