Pull f2fs updates from Jaegeuk Kim:
 "In this round, we've focused on bug fixes since Pixel devices have
  been shipping with f2fs. Some of them were related to hardware
  encryption support which are actually not an issue in mainline, but
  would be better to merge them in order to avoid potential bugs.

  Enhancements:
   - do GC sub-sections when the section is large
   - add a flag in ioctl(SHUTDOWN) to trigger fsck for QA
   - use kvmalloc() in order to give another chance to avoid ENOMEM

  Bug fixes:
   - fix accessing memory boundaries in a malformed iamge
   - GC gives stale unencrypted block
   - GC counts in large sections
   - detect idle time more precisely
   - block allocation of DIO writes
   - race conditions between write_begin and write_checkpoint
   - allow GCs for node segments via ioctl()

  There are various clean-ups and minor bug fixes as well"

* tag 'f2fs-for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (43 commits)
  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
  ...

All callers of migrate_page_move_mapping() now pass NULL for 'head'
argument.  Drop it.

Link: http://lkml.kernel.org/r/20181211172143.7358-7-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There is a security report where f2fs_getxattr() has a hole to expose wrong
memory region when the image is malformed like this.

f2fs_getxattr: entry->e_name_len: 4, size: 12288, buffer_size: 16384, len: 4

Cc: <stable@vger.kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

iput() on sbi->node_inode can update sbi->stat_info
in the below context, if the f2fs_write_checkpoint()
has failed with error.

f2fs_balance_fs_bg+0x1ac/0x1ec
f2fs_write_node_pages+0x4c/0x260
do_writepages+0x80/0xbc
__writeback_single_inode+0xdc/0x4ac
writeback_single_inode+0x9c/0x144
write_inode_now+0xc4/0xec
iput+0x194/0x22c
f2fs_put_super+0x11c/0x1e8
generic_shutdown_super+0x70/0xf4
kill_block_super+0x2c/0x5c
kill_f2fs_super+0x44/0x50
deactivate_locked_super+0x60/0x8c
deactivate_super+0x68/0x74
cleanup_mnt+0x40/0x78

Fix this by moving f2fs_destroy_stats() further below iput() in
both f2fs_put_super() and f2fs_fill_super() paths.

Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

For all ordered cases in f2fs_wait_on_page_writeback(), we need to
check PageWriteback status, so let's clean up to relocate the check
into f2fs_wait_on_page_writeback().

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Treat "block_count" from struct f2fs_super_block as 64-bit little endian
value in sanity_check_raw_super() because struct f2fs_super_block
declares "block_count" as "__le64".

This fixes a bug where the superblock validation fails on big endian
devices with the following error:
  F2FS-fs (sda1): Wrong segment_count / block_count (61439 > 0)
  F2FS-fs (sda1): Can't find valid F2FS filesystem in 1th superblock
  F2FS-fs (sda1): Wrong segment_count / block_count (61439 > 0)
  F2FS-fs (sda1): Can't find valid F2FS filesystem in 2th superblock
As result of this the partition cannot be mounted.

With this patch applied the superblock validation works fine and the
partition can be mounted again:
  F2FS-fs (sda1): Mounted with checkpoint version = 7c84

My little endian x86-64 hardware was able to mount the partition without
this fix.
To confirm that mounting f2fs filesystems works on big endian machines
again I tested this on a 32-bit MIPS big endian (lantiq) device.

Fixes: 0cfe75c5b01199 ("f2fs: enhance sanity_check_raw_super() to avoid potential overflows")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This fixes missing unlock call.

Cc: <stable@vger.kernel.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

If user change inode's i_flags via ioctl, let's add it into global
dirty list, so that checkpoint can guarantee its persistence before
fsync, it can make checkpoint keeping strong consistency.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

The union in struct extent_node wass only to indicate below fields

	struct rb_node rb_node;
	union {
		struct {
			unsigned int fofs;
			unsigned int len;
		...
	...

can be parsed as fields in struct rb_entry, but they were never be
used explicitly before, so let's remove them for cleanup.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Should use lstart (logical start address) instead of start (in dev) here.
This fixes a bug in multi-device scenarios.

Signed-off-by: Qiuyang Sun <sunqiuyang@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>