btrfs-progs: Fix partitioned loop devices resolving

When using partitions on a loop device, the device's name can be
e.g. /dev/loop0p1 or similar, and no relevant entry exists in the /sys
filesystem, so the current resolve_loop_device function fails.

Instead of using string functions to extract the device name and reading
this file, this patch uses the loop device API through ioctl to get the
correct backing file.

Signed-off-by: Florian Margaine <florian@platform.sh>
[ changed checks of error values from open and ioctl ]
Signed-off-by: David Sterba <dsterba@suse.com>

0 files changed, 0 insertions, 0 deletions