On Sat, Nov 07, 2015 at 08:40:16AM +0800, Ming Lei wrote: > The loop direct I/O patches[1] have been merged to linus kernel tree > and will be released in v4.4. > > So the two patches provide interfaces for using direct IO/AIO > in losetup. Thanks! > include/loopdev.h | 4 ++++ > lib/loopdev.c | 40 ++++++++++++++++++++++++++++++++++++++++ > sys-utils/losetup.c | 30 +++++++++++++++++++++++++++--- > 3 files changed, 71 insertions(+), 3 deletions(-) > > [1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bc07c10a3603a5ab3ef01ba42b3d41f9ac63d1b6 If I read correctly the kernel code than LO_FLAGS_DIRECT_IO is not possible to use when initialize loop device by LOOP_SET_FD ioctl. I need extra LOOP_SET_DIRECT_IO ioctl. Why? Why kernel function loop_set_fd() does not initialize lo->use_dio according to "lo_flags & LO_FLAGS_DIRECT_IO" as we use for another loopdev stuff? See for example LO_FLAGS_PARTSCAN. Would be possible to improve kernel a little bit? Now you have to use two commands (ioctls): # losetup /dev/loop0 file.img # losetup --direct-io 1 /dev/loop0 It's fine to use --direct-io as toggle, but it would be nice to support it also when initialize the device. Karel -- Karel Zak <kzak@xxxxxxxxxx> http://karelzak.blogspot.com -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
