Sync ext4 mainline header
Sync with mainline commit b564553

 ext4: print 'flags' in ext4_ext_handle_uninitialized_extents
Sync with mainline commit 19b303d

 ext4: print map->m_flags in trace_ext4_ext/ind_map_blocks_exit
Sync with mainline commit 992e9fd

 ext4: add some tracepoints in extent status tree
Sync rcu header with mainline

3fbfbf7 rcu: Add callback-free CPUs
Sync btrfs header with mainline
Sync with mainline commit fb57dc8

 Btrfs: parse parent 0 into correct value in tracepoint

This fix also apply to previous kernel version, thus no conditional is
required.
Sync with mainline commit 4520fb3

 ext4: split off ext4_journalled_invalidatepage()