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-3.18.y:

6b863986 f2fs: remain written times to update inode during fsync
7e1903bc f2fs: make assignment of t->dentry_bitmap more readable
cb40e79a f2fs: truncate preallocated blocks in error case
61a1f920 f2fs: fix a wrong condition in f2fs_skip_inode_update
60e88b22 f2fs: reserve bits for fs-verity
e9d296fa f2fs: Add a segment type check in inplace write
a6abda93 f2fs: no need to initialize zero value for GFP_F2FS_ZERO
6552559b f2fs: don't track new nat entry in nat set
0a83c6fb f2fs: clean up with F2FS_BLK_ALIGN
561144cb f2fs: check blkaddr more accuratly before issue a bio
f5c308c3 f2fs: Set GF_NOFS in read_cache_page_gfp while doing f2fs_quota_read
b6b63b26 f2fs: introduce a new mount option test_dummy_encryption
2a1db739 f2fs: introduce F2FS_FEATURE_LOST_FOUND feature
8cdc2bd0 f2fs: release locks before return in f2fs_ioc_gc_range()
25cbaa64 f2fs: align memory boundary for bitops
ef169ce0 f2fs: remove unneeded set_cold_node()
893b5cbd f2fs: wrap all options with f2fs_sb_info.mount_opt
e00dfe43 f2fs: Don't overwrite all types of node to keep node chain
8b06bd6a f2fs: introduce mount option for fsync mode
d4f5f926 f2fs: fix to restore old mount option in ->remount_fs
28e06bec f2fs: wrap sb_rdonly with f2fs_readonly
ac00fbd0 f2fs: avoid selinux denial on CAP_SYS_RESOURCE
62141c39 f2fs: support hot file extension
94f9b2bd f2fs: fix to avoid race in between atomic write and background GC
972aa9b7 f2fs: do gc in greedy mode for whole range if gc_urgent mode is set
43df79e0 f2fs: issue discard aggressively in the gc_urgent mode
820bafa8 f2fs: set readdir_ra by default
fd867fad f2fs: add auto tuning for small devices
7135d061 f2fs: add mount option for segment allocation policy
1010797c f2fs: don't stop GC if GC is contended
07b7ac02 f2fs: expose extension_list sysfs entry
d3f1ecce f2fs: fix to set KEEP_SIZE bit in f2fs_zero_range
6a2a51a3 f2fs: introduce sb_lock to make encrypt pwsalt update exclusive
b25cb37a f2fs: remove redundant initialization of pointer 'p'
f712a5e9 f2fs: flush cp pack except cp pack 2 page at first
9cc8ab4e f2fs: clean up f2fs_sb_has_xxx functions
e7e6b338 f2fs: remove redundant check of page type when submit bio
00e3ba7f f2fs: fix to handle looped node chain during recovery
878a8d3c f2fs: handle quota for orphan inodes
5b20df49 f2fs: support passing down write hints to block layer with F2FS policy
249b112b f2fs: support passing down write hints given by users to block layer
3b8cef6e f2fs: fix to clear CP_TRIMMED_FLAG
f7729557 f2fs: support large nat bitmap
b3fea69d f2fs: fix to check extent cache in f2fs_drop_extent_tree
e01f7086 f2fs: restrict inline_xattr_size configuration
956a72d8 f2fs: fix heap mode to reset it back
08cdc841 f2fs: fix potential corruption in area before F2FS_SUPER_OFFSET
9c696c1f fscrypt: fix build with pre-4.6 gcc versions
db4247d1 fscrypt: remove 'ci' parameter from fscrypt_put_encryption_info()
29127d39 fscrypt: fix up fscrypt_fname_encrypted_size() for internal use
439466d2 fscrypt: define fscrypt_fname_alloc_buffer() to be for presented names
e3311020 fscrypt: calculate NUL-padding length in one place only
a7f4d8ac fscrypt: move fscrypt_symlink_data to fscrypt_private.h
5ea58407 fscrypt: remove fscrypt_fname_usr_to_disk()
81b1614f f2fs: switch to fscrypt_get_symlink()
aef534bb f2fs: switch to fscrypt ->symlink() helper functions
39829378 fscrypt: new helper function - fscrypt_get_symlink()
fcc38431 fscrypt: new helper functions for ->symlink()
82b04f2d fscrypt: trim down fscrypt.h includes
9b0ef251 fscrypt: move fscrypt_is_dot_dotdot() to fs/crypto/fname.c
8319d163 fscrypt: move fscrypt_valid_enc_modes() to fscrypt_private.h
02cbbef8 fscrypt: move fscrypt_operations declaration to fscrypt_supp.h
646d687f fscrypt: split fscrypt_dummy_context_enabled() into supp/notsupp versions
fc0f52e7 fscrypt: move fscrypt_ctx declaration to fscrypt_supp.h
1f8b1364 fscrypt: move fscrypt_info_cachep declaration to fscrypt_private.h
67a6c99f fscrypt: move fscrypt_control_page() to supp/notsupp headers
2099761d fscrypt: move fscrypt_has_encryption_key() to supp/notsupp headers

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