btrfs: log replay after fsync of file with prealloc extents beyond eof

btrfs: log replay after fsync of file with prealloc extents beyond eof

Test that after a full fsync of a file with preallocated extents
beyond the file's size, if a power failure happens, the preallocated
extents still exist after we mount the filesystem.

This test currently fails and there is a patch for btrfs that fixes
this issue and has the following subject:

  "btrfs: fix lost prealloc extents beyond eof after full fsync"

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>