Merge upstream-f2fs-stable-linux-4.19.y into android-4.19

Additional urgent fixes on top of 5.0-rc1-4.19:
  f2fs: don't access node/meta inode mapping after iput
  f2fs: wait on atomic writes to count F2FS_CP_WB_DATA

* origin/upstream-f2fs-stable-linux-4.19.y:
  f2fs: don't access node/meta inode mapping after iput
  f2fs: wait on atomic writes to count F2FS_CP_WB_DATA
  f2fs: sanity check of xattr entry size
  f2fs: fix use-after-free issue when accessing sbi->stat_info
  f2fs: check PageWriteback flag for ordered case
  f2fs: fix validation of the block count in sanity_check_raw_super
  f2fs: fix missing unlock(sbi->gc_mutex)
  f2fs: fix to dirty inode synchronously
  f2fs: clean up structure extent_node
  f2fs: fix block address for __check_sit_bitmap
  f2fs: fix sbi->extent_list corruption issue
  f2fs: clean up checkpoint flow
  f2fs: flush stale issued discard candidates
  f2fs: correct wrong spelling, issing_*
  f2fs: use kvmalloc, if kmalloc is failed
  f2fs: remove redundant comment of unused wio_mutex
  f2fs: fix to reorder set_page_dirty and wait_on_page_writeback
  f2fs: clear PG_writeback if IPU failed
  f2fs: add an ioctl() to explicitly trigger fsck later
  f2fs: avoid frequent costly fsck triggers
  f2fs: fix m_may_create to make OPU DIO write correctly
  f2fs: fix to update new block address correctly for OPU
  f2fs: adjust trace print in f2fs_get_victim() to cover all paths
  f2fs: fix to allow node segment for GC by ioctl path
  f2fs: make "f2fs_fault_name[]" const char *
  f2fs: read page index before freeing
  f2fs: fix wrong return value of f2fs_acl_create
  f2fs: avoid build warn of fall_through
  f2fs: fix race between write_checkpoint and write_begin
  f2fs: check memory boundary by insane namelen
  f2fs: only flush the single temp bio cache which owns the target page
  f2fs: fix out-place-update DIO write
  f2fs: fix to be aware discard/preflush/dio command in is_idle()
  f2fs: add to account direct IO
  f2fs: move dir data flush to write checkpoint process
  f2fs: Change to use DEFINE_SHOW_ATTRIBUTE macro
  f2fs: change segment to section in f2fs_ioc_gc_range
  f2fs: export migration_granularity sysfs entry
  f2fs: support subsectional garbage collection
  f2fs: introduce __is_large_section() for cleanup
  f2fs: clean up f2fs_sb_has_##feature_name
  f2fs: remove codes of unused wio_mutex
  f2fs: fix count of seg_freed to make sec_freed correct
  f2fs: fix to account preflush command for noflush_merge mode
  f2fs: avoid GC causing encrypted file corrupted

Change-Id: I3d7a2ae091d9df3f4466d9815b55ce3573ae7596
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>