f2fs/fscrypt: updates to v4.17-rc1

Pull f2fs update from Jaegeuk Kim:
 "In this round, we've mainly focused on performance tuning and critical
  bug fixes occurred in low-end devices. Sheng Yong introduced
  lost_found feature to keep missing files during recovery instead of
  thrashing them. We're preparing coming fsverity implementation. And,
  we've got more features to communicate with users for better
  performance. In low-end devices, some memory-related issues were
  fixed, and subtle race condtions and corner cases were addressed as
  well.

  Enhancements:
   - large nat bitmaps for more free node ids
   - add three block allocation policies to pass down write hints given by user
   - expose extension list to user and introduce hot file extension
   - tune small devices seamlessly for low-end devices
   - set readdir_ra by default
   - give more resources under gc_urgent mode regarding to discard and cleaning
   - introduce fsync_mode to enforce posix or not
   - nowait aio support
   - add lost_found feature to keep dangling inodes
   - reserve bits for future fsverity feature
   - add test_dummy_encryption for FBE

  Bug fixes:
   - don't use highmem for dentry pages
   - align memory boundary for bitops
   - truncate preallocated blocks in write errors
   - guarantee i_times on fsync call
   - clear CP_TRIMMED_FLAG correctly
   - prevent node chain loop during recovery
   - avoid data race between atomic write and background cleaning
   - avoid unnecessary selinux violation warnings on resgid option
   - GFP_NOFS to avoid deadlock in quota and read paths
   - fix f2fs_skip_inode_update to allow i_size recovery

  In addition to the above, there are several minor bug fixes and clean-ups"

Cherry-pick from origin/upstream-f2fs-stable-linux-4.9.y:

ac389af1 f2fs: remain written times to update inode during fsync
270deeb8 f2fs: make assignment of t->dentry_bitmap more readable
a4fa11c8 f2fs: truncate preallocated blocks in error case
4478970f f2fs: fix a wrong condition in f2fs_skip_inode_update
29cead58 f2fs: reserve bits for fs-verity
848b293a f2fs: Add a segment type check in inplace write
2dc8f5a3 f2fs: no need to initialize zero value for GFP_F2FS_ZERO
83b9bb95 f2fs: don't track new nat entry in nat set
a33ce03a f2fs: clean up with F2FS_BLK_ALIGN
a3f8ec80 f2fs: check blkaddr more accuratly before issue a bio
034f11ea f2fs: Set GF_NOFS in read_cache_page_gfp while doing f2fs_quota_read
aa5bcfd8 f2fs: introduce a new mount option test_dummy_encryption
9b880fe6 f2fs: introduce F2FS_FEATURE_LOST_FOUND feature
80d6489a f2fs: release locks before return in f2fs_ioc_gc_range()
9f1896c4 f2fs: align memory boundary for bitops
c7930ee8 f2fs: remove unneeded set_cold_node()
355d2346 f2fs: add nowait aio support
e9a50e6b f2fs: wrap all options with f2fs_sb_info.mount_opt
b6d2ec83 f2fs: Don't overwrite all types of node to keep node chain
9a954816 f2fs: introduce mount option for fsync mode
4ce4eb69 f2fs: fix to restore old mount option in ->remount_fs
8f711c34 f2fs: wrap sb_rdonly with f2fs_readonly
c07478ee f2fs: avoid selinux denial on CAP_SYS_RESOURCE
ac734c41 f2fs: support hot file extension
f4f10221 f2fs: fix to avoid race in between atomic write and background GC
e87b13ec f2fs: do gc in greedy mode for whole range if gc_urgent mode is set
e9878588 f2fs: issue discard aggressively in the gc_urgent mode
ad3ce479 f2fs: set readdir_ra by default
5aae2026 f2fs: add auto tuning for small devices
78c1fc2d f2fs: add mount option for segment allocation policy
ecd02f56 f2fs: don't stop GC if GC is contended
1e72cb27 f2fs: expose extension_list sysfs entry
061839d1 f2fs: fix to set KEEP_SIZE bit in f2fs_zero_range
4951ebcb f2fs: introduce sb_lock to make encrypt pwsalt update exclusive
939f6be0 f2fs: remove redundant initialization of pointer 'p'
39bea4bc f2fs: flush cp pack except cp pack 2 page at first
770611eb f2fs: clean up f2fs_sb_has_xxx functions
4d8e4a89 f2fs: remove redundant check of page type when submit bio
e9878588 f2fs: issue discard aggressively in the gc_urgent mode
ad3ce479 f2fs: set readdir_ra by default
5aae2026 f2fs: add auto tuning for small devices
78c1fc2d f2fs: add mount option for segment allocation policy
ecd02f56 f2fs: don't stop GC if GC is contended
1e72cb27 f2fs: expose extension_list sysfs entry
061839d1 f2fs: fix to set KEEP_SIZE bit in f2fs_zero_range
4951ebcb f2fs: introduce sb_lock to make encrypt pwsalt update exclusive
939f6be0 f2fs: remove redundant initialization of pointer 'p'
39bea4bc f2fs: flush cp pack except cp pack 2 page at first
770611eb f2fs: clean up f2fs_sb_has_xxx functions
4d8e4a89 f2fs: remove redundant check of page type when submit bio
b57a37f0 f2fs: fix to handle looped node chain during recovery
9ac5b8c5 f2fs: handle quota for orphan inodes
87c18066 f2fs: support passing down write hints to block layer with F2FS policy
bcdc571e f2fs: support passing down write hints given by users to block layer
92413bc1 f2fs: fix to clear CP_TRIMMED_FLAG
a1afb55f f2fs: support large nat bitmap
63603914 f2fs: fix to check extent cache in f2fs_drop_extent_tree
7de4fccd f2fs: restrict inline_xattr_size configuration
aae506a8 f2fs: fix heap mode to reset it back
8fa455bb f2fs: fix potential corruption in area before F2FS_SUPER_OFFSET
9d9cb0ef fscrypt: fix build with pre-4.6 gcc versions
401052ff fscrypt: remove 'ci' parameter from fscrypt_put_encryption_info()
549b2061 fscrypt: fix up fscrypt_fname_encrypted_size() for internal use
c440b509 fscrypt: define fscrypt_fname_alloc_buffer() to be for presented names
7d82f0e1 ext4: switch to fscrypt ->symlink() helper functions
ba4efe56 ext4: switch to fscrypt_get_symlink()
b0edc2f2 fscrypt: calculate NUL-padding length in one place only
62cfdd98 fscrypt: move fscrypt_symlink_data to fscrypt_private.h
e4e67765 fscrypt: remove fscrypt_fname_usr_to_disk()
45028b5a f2fs: switch to fscrypt_get_symlink()
f62d3d31 f2fs: switch to fscrypt ->symlink() helper functions
da32a163 fscrypt: new helper function - fscrypt_get_symlink()
a7e05c73 fscrypt: new helper functions for ->symlink()
eb9c5fd8 fscrypt: trim down fscrypt.h includes
0a02472d fscrypt: move fscrypt_is_dot_dotdot() to fs/crypto/fname.c
9d51ca80 fscrypt: move fscrypt_valid_enc_modes() to fscrypt_private.h
efbfa8c6 fscrypt: move fscrypt_operations declaration to fscrypt_supp.h
616dbd2b fscrypt: split fscrypt_dummy_context_enabled() into supp/notsupp versions
f0c472bc fscrypt: move fscrypt_ctx declaration to fscrypt_supp.h
bc76f391 fscrypt: move fscrypt_info_cachep declaration to fscrypt_private.h
b67b07ec fscrypt: move fscrypt_control_page() to supp/notsupp headers
d8dfb899 fscrypt: move fscrypt_has_encryption_key() to supp/notsupp headers

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