[Qemu-block] [PATCH 0/2] block: Do OFD lock check at runtime

[Fam Zheng]

This fixes the image opening failure reported by Andrew Baumann:

> I'm running a recent Linux build of qemu on Windows Subsystem for Linux (WSL)
> which doesn't appear to implement file locking:
>
> $ 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

It appears to be that the binary is built for Linux targets, but the WSL
runtime doesn't recognize the ops (-EINVAL).

Convert to runtime check to cope with that.

Fam Zheng (2):
  osdep: Add runtime OFD lock detection
  file-posix: Do runtime check for ofd lock API

 block/file-posix.c   | 19 ++++++--------
 include/qemu/osdep.h |  1 +
 util/osdep.c         | 72 +++++++++++++++++++++++++++++++++++++++++++++-------
 3 files changed, 72 insertions(+), 20 deletions(-)

-- 
2.13.3