btrfs: new test for logical inode resolution panic

btrfs: new test for logical inode resolution panic

If we create a file that has an inline extent followed by a prealloc
extent, then attempt to use the logical to inode ioctl on the prealloc
extent, but in the overwritten range, backref resolution will process
the inline extent. Depending on the leaf eb layout, this can panic.
Add a new test for this condition. In the long run, we can add spew when
we read out-of-bounds fields of inline extent items and simplify this
test to look for dmesg warnings rather than trying to force a fairly
fragile panic (dependent on non-standardized details of leaf layout).

The test causes a kernel panic unless:
btrfs: fix logical_ino ioctl panic
is applied to the kernel.

Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>