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-4.4.y:

42bf67fc543b f2fs: remain written times to update inode during fsync
6cb5aa02bfbd f2fs: make assignment of t->dentry_bitmap more readable
a8d07f1f9c62 f2fs: truncate preallocated blocks in error case
86444d600692 f2fs: fix a wrong condition in f2fs_skip_inode_update
db2188a68704 f2fs: reserve bits for fs-verity
ee2e74b3f00e f2fs: Add a segment type check in inplace write
0192e0a4502f f2fs: no need to initialize zero value for GFP_F2FS_ZERO
49338842e9b2 f2fs: don't track new nat entry in nat set
d6a69d5e6568 f2fs: clean up with F2FS_BLK_ALIGN
2c8834a7a2c9 f2fs: check blkaddr more accuratly before issue a bio
6ab573a9d96f f2fs: Set GF_NOFS in read_cache_page_gfp while doing f2fs_quota_read
7419dcb8be02 f2fs: introduce a new mount option test_dummy_encryption
9321e22c038c f2fs: introduce F2FS_FEATURE_LOST_FOUND feature
8a5719615847 f2fs: release locks before return in f2fs_ioc_gc_range()
739ace131cdf f2fs: align memory boundary for bitops
4c55abe4f8d2 f2fs: remove unneeded set_cold_node()
30654507e0a2 f2fs: add nowait aio support
d909e9410634 f2fs: wrap all options with f2fs_sb_info.mount_opt
5738be52b3e8 f2fs: Don't overwrite all types of node to keep node chain
0bdeb167c843 f2fs: introduce mount option for fsync mode
6bc490f0eedc f2fs: fix to restore old mount option in ->remount_fs
0c9c3e034410 f2fs: wrap sb_rdonly with f2fs_readonly
6c6611223a79 f2fs: avoid selinux denial on CAP_SYS_RESOURCE
076a6f32fe5d f2fs: support hot file extension
58edcdbca67a f2fs: fix to avoid race in between atomic write and background GC
1e0aeb0af9ed f2fs: do gc in greedy mode for whole range if gc_urgent mode is set
10b2d001d6ac f2fs: issue discard aggressively in the gc_urgent mode
a5052f32b940 f2fs: set readdir_ra by default
1aa536a624cc f2fs: add auto tuning for small devices
0ffdffc8f106 f2fs: add mount option for segment allocation policy
b79829891249 f2fs: don't stop GC if GC is contended
766d2321697f f2fs: expose extension_list sysfs entry
98b329de5026 f2fs: fix to set KEEP_SIZE bit in f2fs_zero_range
4d409fa3346b f2fs: introduce sb_lock to make encrypt pwsalt update exclusive
1f6bac14c100 f2fs: remove redundant initialization of pointer 'p'
946aefc7545d f2fs: flush cp pack except cp pack 2 page at first
e5081a52ac09 f2fs: clean up f2fs_sb_has_xxx functions
a292477154b5 f2fs: remove redundant check of page type when submit bio
190e64a819df f2fs: fix to handle looped node chain during recovery
889d98087652 f2fs: handle quota for orphan inodes
92b12bb1a23e f2fs: support passing down write hints to block layer with F2FS policy
22fa74c2b097 f2fs: support passing down write hints given by users to block layer
180900373ec1 f2fs: fix to clear CP_TRIMMED_FLAG
0671fae134bb f2fs: support large nat bitmap
eceb943d5d59 f2fs: fix to check extent cache in f2fs_drop_extent_tree
2e2a339c9853 f2fs: restrict inline_xattr_size configuration
41dda1164137 f2fs: fix heap mode to reset it back
39575737bb62 f2fs: fix potential corruption in area before F2FS_SUPER_OFFSET
7e0e7995ee97 fscrypt: fix build with pre-4.6 gcc versions
31d3279a4fca fscrypt: fix up fscrypt_fname_encrypted_size() for internal use
82bec888567b fscrypt: define fscrypt_fname_alloc_buffer() to be for presented names
168a90782888 fscrypt: calculate NUL-padding length in one place only
042ae9f4cfbf fscrypt: move fscrypt_symlink_data to fscrypt_private.h
f9550c24c20e fscrypt: remove fscrypt_fname_usr_to_disk()
7ac4756a2474 f2fs: switch to fscrypt_get_symlink()
6b76f58e24bd f2fs: switch to fscrypt ->symlink() helper functions
fd457d2c4e04 fscrypt: new helper function - fscrypt_get_symlink()
a1cdacb7ae0d fscrypt: new helper functions for ->symlink()
7f43602f4d10 fscrypt: trim down fscrypt.h includes
d9cadc11bdcf fscrypt: move fscrypt_is_dot_dotdot() to fs/crypto/fname.c
e6fe930580cb fscrypt: move fscrypt_valid_enc_modes() to fscrypt_private.h
efefa434f47e fscrypt: move fscrypt_operations declaration to fscrypt_supp.h
7ed178bc8ae9 fscrypt: split fscrypt_dummy_context_enabled() into supp/notsupp versions
3f16e09dadfb fscrypt: move fscrypt_ctx declaration to fscrypt_supp.h
8216a0b51a3b fscrypt: move fscrypt_info_cachep declaration to fscrypt_private.h
dfe0b3b1b67f fscrypt: move fscrypt_control_page() to supp/notsupp headers
3a2c79177822 fscrypt: move fscrypt_has_encryption_key() to supp/notsupp headers

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

6 files changed, 200 insertions, 135 deletions

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 0fb65843ec1e..f0942a82bb20 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -47,6 +47,7 @@ struct bio {
 	struct bio		*bi_next;	/* request queue link */
 	struct block_device	*bi_bdev;
 	unsigned int		bi_flags;	/* status, command, etc */
+	unsigned short		bi_write_hint;
 	int			bi_error;
 	unsigned long		bi_rw;		/* bottom bits READ/WRITE,
 						 * top bits priority
diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index 073365c9808a..2ebfa01b7091 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -21,6 +21,7 @@
 #define F2FS_BLKSIZE			4096	/* support only 4KB block */
 #define F2FS_BLKSIZE_BITS		12	/* bits for F2FS_BLKSIZE */
 #define F2FS_MAX_EXTENSION		64	/* # of extension entries */
+#define F2FS_EXTENSION_LEN		8	/* max size of extension */
 #define F2FS_BLK_ALIGN(x)	(((x) + F2FS_BLKSIZE - 1) >> F2FS_BLKSIZE_BITS)
 
 #define NULL_ADDR		((block_t)0)	/* used as block_t addresses */
@@ -38,10 +39,10 @@
 
 #define F2FS_MAX_QUOTAS		3
 
-#define F2FS_IO_SIZE(sbi)	(1 << (sbi)->write_io_size_bits) /* Blocks */
-#define F2FS_IO_SIZE_KB(sbi)	(1 << ((sbi)->write_io_size_bits + 2)) /* KB */
-#define F2FS_IO_SIZE_BYTES(sbi)	(1 << ((sbi)->write_io_size_bits + 12)) /* B */
-#define F2FS_IO_SIZE_BITS(sbi)	((sbi)->write_io_size_bits) /* power of 2 */
+#define F2FS_IO_SIZE(sbi)	(1 << F2FS_OPTION(sbi).write_io_size_bits) /* Blocks */
+#define F2FS_IO_SIZE_KB(sbi)	(1 << (F2FS_OPTION(sbi).write_io_size_bits + 2)) /* KB */
+#define F2FS_IO_SIZE_BYTES(sbi)	(1 << (F2FS_OPTION(sbi).write_io_size_bits + 12)) /* B */
+#define F2FS_IO_SIZE_BITS(sbi)	(F2FS_OPTION(sbi).write_io_size_bits) /* power of 2 */
 #define F2FS_IO_SIZE_MASK(sbi)	(F2FS_IO_SIZE(sbi) - 1)
 
 /* This flag is used by node and meta inodes, and by recovery */
@@ -101,7 +102,7 @@ struct f2fs_super_block {
 	__u8 uuid[16];			/* 128-bit uuid for volume */
 	__le16 volume_name[MAX_VOLUME_NAME];	/* volume name */
 	__le32 extension_count;		/* # of extensions below */
-	__u8 extension_list[F2FS_MAX_EXTENSION][8];	/* extension array */
+	__u8 extension_list[F2FS_MAX_EXTENSION][F2FS_EXTENSION_LEN];/* extension array */
 	__le32 cp_payload;
 	__u8 version[VERSION_LEN];	/* the kernel version */
 	__u8 init_version[VERSION_LEN];	/* the initial kernel version */
@@ -110,12 +111,14 @@ struct f2fs_super_block {
 	__u8 encrypt_pw_salt[16];	/* Salt used for string2key algorithm */
 	struct f2fs_device devs[MAX_DEVICES];	/* device list */
 	__le32 qf_ino[F2FS_MAX_QUOTAS];	/* quota inode numbers */
-	__u8 reserved[315];		/* valid reserved region */
+	__u8 hot_ext_count;		/* # of hot file extension */
+	__u8 reserved[314];		/* valid reserved region */
 } __packed;
 
 /*
  * For checkpoint
  */
+#define CP_LARGE_NAT_BITMAP_FLAG	0x00000400
 #define CP_NOCRC_RECOVERY_FLAG	0x00000200
 #define CP_TRIMMED_FLAG		0x00000100
 #define CP_NAT_BITS_FLAG	0x00000080
@@ -302,6 +305,10 @@ struct f2fs_node {
  */
 #define NAT_ENTRY_PER_BLOCK (PAGE_SIZE / sizeof(struct f2fs_nat_entry))
 #define NAT_ENTRY_BITMAP_SIZE	((NAT_ENTRY_PER_BLOCK + 7) / 8)
+#define NAT_ENTRY_BITMAP_SIZE_ALIGNED				\
+	((NAT_ENTRY_BITMAP_SIZE + BITS_PER_LONG - 1) /		\
+	BITS_PER_LONG * BITS_PER_LONG)
+
 
 struct f2fs_nat_entry {
 	__u8 version;		/* latest version of cached nat entry */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 16c8235bc0d2..cfb6ff61df30 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -20,6 +20,7 @@
 #include <linux/rwsem.h>
 #include <linux/capability.h>
 #include <linux/semaphore.h>
+#include <linux/fcntl.h>
 #include <linux/fiemap.h>
 #include <linux/rculist_bl.h>
 #include <linux/atomic.h>
@@ -143,6 +144,9 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
 /* File was opened by fanotify and shouldn't generate fanotify events */
 #define FMODE_NONOTIFY		((__force fmode_t)0x4000000)
 
+/* File is capable of returning -EAGAIN if I/O will block */
+#define FMODE_NOWAIT		((__force fmode_t)0x8000000)
+
 /*
  * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector
  * that indicates that they should check the contents of the iovec are
@@ -319,9 +323,22 @@ struct page;
 struct address_space;
 struct writeback_control;
 
+/*
+ * Write life time hint values.
+ */
+enum rw_hint {
+	WRITE_LIFE_NOT_SET	= 0,
+	WRITE_LIFE_NONE		= RWH_WRITE_LIFE_NONE,
+	WRITE_LIFE_SHORT	= RWH_WRITE_LIFE_SHORT,
+	WRITE_LIFE_MEDIUM	= RWH_WRITE_LIFE_MEDIUM,
+	WRITE_LIFE_LONG		= RWH_WRITE_LIFE_LONG,
+	WRITE_LIFE_EXTREME	= RWH_WRITE_LIFE_EXTREME,
+};
+
 #define IOCB_EVENTFD		(1 << 0)
 #define IOCB_APPEND		(1 << 1)
 #define IOCB_DIRECT		(1 << 2)
+#define IOCB_NOWAIT		(1 << 7)
 
 struct kiocb {
 	struct file		*ki_filp;
@@ -329,6 +346,7 @@ struct kiocb {
 	void (*ki_complete)(struct kiocb *iocb, long ret, long ret2);
 	void			*private;
 	int			ki_flags;
+	enum rw_hint		ki_hint;
 };
 
 static inline bool is_sync_kiocb(struct kiocb *kiocb)
@@ -625,6 +643,7 @@ struct inode {
 	spinlock_t		i_lock;	/* i_blocks, i_bytes, maybe i_size */
 	unsigned short          i_bytes;
 	unsigned int		i_blkbits;
+	enum rw_hint		i_write_hint;
 	blkcnt_t		i_blocks;
 
 #ifdef __NEED_I_SIZE_ORDERED
@@ -1059,8 +1078,6 @@ struct file_lock_context {
 #define OFFT_OFFSET_MAX	INT_LIMIT(off_t)
 #endif
 
-#include <linux/fcntl.h>
-
 extern void send_sigio(struct fown_struct *fown, int fd, int band);
 
 #ifdef CONFIG_FILE_LOCKING
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 8641e56b8f8a..9e535af579e8 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -13,42 +13,13 @@
 #ifndef _LINUX_FSCRYPT_H
 #define _LINUX_FSCRYPT_H
 
-#include <linux/key.h>
 #include <linux/fs.h>
-#include <linux/mm.h>
-#include <linux/bio.h>
-#include <linux/dcache.h>
-#include <crypto/skcipher.h>
-#include <uapi/linux/fs.h>
 
 #define FS_CRYPTO_BLOCK_SIZE		16
 
+struct fscrypt_ctx;
 struct fscrypt_info;
 
-struct fscrypt_ctx {
-	union {
-		struct {
-			struct page *bounce_page;	/* Ciphertext page */
-			struct page *control_page;	/* Original page  */
-		} w;
-		struct {
-			struct bio *bio;
-			struct work_struct work;
-		} r;
-		struct list_head free_list;	/* Free list */
-	};
-	u8 flags;				/* Flags */
-};
-
-/**
- * For encrypted symlinks, the ciphertext length is stored at the beginning
- * of the string in little-endian format.
- */
-struct fscrypt_symlink_data {
-	__le16 len;
-	char encrypted_path[1];
-} __packed;
-
 struct fscrypt_str {
 	unsigned char *name;
 	u32 len;
@@ -67,86 +38,11 @@ struct fscrypt_name {
 #define fname_name(p)		((p)->disk_name.name)
 #define fname_len(p)		((p)->disk_name.len)
 
-/*
- * fscrypt superblock flags
- */
-#define FS_CFLG_OWN_PAGES (1U << 1)
-
-/*
- * crypto opertions for filesystems
- */
-struct fscrypt_operations {
-	unsigned int flags;
-	const char *key_prefix;
-	int (*get_context)(struct inode *, void *, size_t);
-	int (*set_context)(struct inode *, const void *, size_t, void *);
-	bool (*dummy_context)(struct inode *);
-	bool (*empty_dir)(struct inode *);
-	unsigned (*max_namelen)(struct inode *);
-};
-
-static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
-{
-	if (inode->i_sb->s_cop->dummy_context &&
-				inode->i_sb->s_cop->dummy_context(inode))
-		return true;
-	return false;
-}
-
-static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
-					u32 filenames_mode)
-{
-	if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC &&
-	    filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS)
-		return true;
-
-	if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS &&
-	    filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS)
-		return true;
-
-	return false;
-}
-
-static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
-{
-	if (str->len == 1 && str->name[0] == '.')
-		return true;
-
-	if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
-		return true;
-
-	return false;
-}
-
 #if __FS_HAS_ENCRYPTION
-
-static inline struct page *fscrypt_control_page(struct page *page)
-{
-	return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
-}
-
-static inline bool fscrypt_has_encryption_key(const struct inode *inode)
-{
-	return (inode->i_crypt_info != NULL);
-}
-
 #include <linux/fscrypt_supp.h>
-
-#else /* !__FS_HAS_ENCRYPTION */
-
-static inline struct page *fscrypt_control_page(struct page *page)
-{
-	WARN_ON_ONCE(1);
-	return ERR_PTR(-EINVAL);
-}
-
-static inline bool fscrypt_has_encryption_key(const struct inode *inode)
-{
-	return 0;
-}
-
+#else
 #include <linux/fscrypt_notsupp.h>
-#endif /* __FS_HAS_ENCRYPTION */
+#endif
 
 /**
  * fscrypt_require_key - require an inode's encryption key
@@ -287,4 +183,68 @@ static inline int fscrypt_prepare_setattr(struct dentry *dentry,
 	return 0;
 }
 
+/**
+ * fscrypt_prepare_symlink - prepare to create a possibly-encrypted symlink
+ * @dir: directory in which the symlink is being created
+ * @target: plaintext symlink target
+ * @len: length of @target excluding null terminator
+ * @max_len: space the filesystem has available to store the symlink target
+ * @disk_link: (out) the on-disk symlink target being prepared
+ *
+ * This function computes the size the symlink target will require on-disk,
+ * stores it in @disk_link->len, and validates it against @max_len.  An
+ * encrypted symlink may be longer than the original.
+ *
+ * Additionally, @disk_link->name is set to @target if the symlink will be
+ * unencrypted, but left NULL if the symlink will be encrypted.  For encrypted
+ * symlinks, the filesystem must call fscrypt_encrypt_symlink() to create the
+ * on-disk target later.  (The reason for the two-step process is that some
+ * filesystems need to know the size of the symlink target before creating the
+ * inode, e.g. to determine whether it will be a "fast" or "slow" symlink.)
+ *
+ * Return: 0 on success, -ENAMETOOLONG if the symlink target is too long,
+ * -ENOKEY if the encryption key is missing, or another -errno code if a problem
+ * occurred while setting up the encryption key.
+ */
+static inline int fscrypt_prepare_symlink(struct inode *dir,
+					  const char *target,
+					  unsigned int len,
+					  unsigned int max_len,
+					  struct fscrypt_str *disk_link)
+{
+	if (IS_ENCRYPTED(dir) || fscrypt_dummy_context_enabled(dir))
+		return __fscrypt_prepare_symlink(dir, len, max_len, disk_link);
+
+	disk_link->name = (unsigned char *)target;
+	disk_link->len = len + 1;
+	if (disk_link->len > max_len)
+		return -ENAMETOOLONG;
+	return 0;
+}
+
+/**
+ * fscrypt_encrypt_symlink - encrypt the symlink target if needed
+ * @inode: symlink inode
+ * @target: plaintext symlink target
+ * @len: length of @target excluding null terminator
+ * @disk_link: (in/out) the on-disk symlink target being prepared
+ *
+ * If the symlink target needs to be encrypted, then this function encrypts it
+ * into @disk_link->name.  fscrypt_prepare_symlink() must have been called
+ * previously to compute @disk_link->len.  If the filesystem did not allocate a
+ * buffer for @disk_link->name after calling fscrypt_prepare_link(), then one
+ * will be kmalloc()'ed and the filesystem will be responsible for freeing it.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static inline int fscrypt_encrypt_symlink(struct inode *inode,
+					  const char *target,
+					  unsigned int len,
+					  struct fscrypt_str *disk_link)
+{
+	if (IS_ENCRYPTED(inode))
+		return __fscrypt_encrypt_symlink(inode, target, len, disk_link);
+	return 0;
+}
+
 #endif	/* _LINUX_FSCRYPT_H */
diff --git a/include/linux/fscrypt_notsupp.h b/include/linux/fscrypt_notsupp.h
index c4c6bf2c390e..5777251400f9 100644
--- a/include/linux/fscrypt_notsupp.h
+++ b/include/linux/fscrypt_notsupp.h
@@ -13,6 +13,16 @@
 #ifndef _LINUX_FSCRYPT_NOTSUPP_H
 #define _LINUX_FSCRYPT_NOTSUPP_H
 
+static inline bool fscrypt_has_encryption_key(const struct inode *inode)
+{
+	return false;
+}
+
+static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
+{
+	return false;
+}
+
 /* crypto.c */
 static inline struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *inode,
 						  gfp_t gfp_flags)
@@ -42,6 +52,11 @@ static inline int fscrypt_decrypt_page(const struct inode *inode,
 	return -EOPNOTSUPP;
 }
 
+static inline struct page *fscrypt_control_page(struct page *page)
+{
+	WARN_ON_ONCE(1);
+	return ERR_PTR(-EINVAL);
+}
 
 static inline void fscrypt_restore_control_page(struct page *page)
 {
@@ -115,16 +130,8 @@ static inline void fscrypt_free_filename(struct fscrypt_name *fname)
 	return;
 }
 
-static inline u32 fscrypt_fname_encrypted_size(const struct inode *inode,
-					       u32 ilen)
-{
-	/* never happens */
-	WARN_ON(1);
-	return 0;
-}
-
 static inline int fscrypt_fname_alloc_buffer(const struct inode *inode,
-					     u32 ilen,
+					     u32 max_encrypted_len,
 					     struct fscrypt_str *crypto_str)
 {
 	return -EOPNOTSUPP;
@@ -143,13 +150,6 @@ static inline int fscrypt_fname_disk_to_usr(struct inode *inode,
 	return -EOPNOTSUPP;
 }
 
-static inline int fscrypt_fname_usr_to_disk(struct inode *inode,
-					    const struct qstr *iname,
-					    struct fscrypt_str *oname)
-{
-	return -EOPNOTSUPP;
-}
-
 static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
 				      const u8 *de_name, u32 de_name_len)
 {
@@ -207,4 +207,27 @@ static inline int __fscrypt_prepare_lookup(struct inode *dir,
 	return -EOPNOTSUPP;
 }
 
+static inline int __fscrypt_prepare_symlink(struct inode *dir,
+					    unsigned int len,
+					    unsigned int max_len,
+					    struct fscrypt_str *disk_link)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int __fscrypt_encrypt_symlink(struct inode *inode,
+					    const char *target,
+					    unsigned int len,
+					    struct fscrypt_str *disk_link)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void *fscrypt_get_symlink(struct inode *inode,
+					      const void *caddr,
+					      unsigned int max_size)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
 #endif	/* _LINUX_FSCRYPT_NOTSUPP_H */
diff --git a/include/linux/fscrypt_supp.h b/include/linux/fscrypt_supp.h
index 2db5e9706f60..c88d2058902a 100644
--- a/include/linux/fscrypt_supp.h
+++ b/include/linux/fscrypt_supp.h
@@ -10,8 +10,54 @@
 #ifndef _LINUX_FSCRYPT_SUPP_H
 #define _LINUX_FSCRYPT_SUPP_H
 
+#include <linux/mm.h>
+#include <linux/slab.h>
+
+/*
+ * fscrypt superblock flags
+ */
+#define FS_CFLG_OWN_PAGES (1U << 1)
+
+/*
+ * crypto operations for filesystems
+ */
+struct fscrypt_operations {
+	unsigned int flags;
+	const char *key_prefix;
+	int (*get_context)(struct inode *, void *, size_t);
+	int (*set_context)(struct inode *, const void *, size_t, void *);
+	bool (*dummy_context)(struct inode *);
+	bool (*empty_dir)(struct inode *);
+	unsigned (*max_namelen)(struct inode *);
+};
+
+struct fscrypt_ctx {
+	union {
+		struct {
+			struct page *bounce_page;	/* Ciphertext page */
+			struct page *control_page;	/* Original page  */
+		} w;
+		struct {
+			struct bio *bio;
+			struct work_struct work;
+		} r;
+		struct list_head free_list;	/* Free list */
+	};
+	u8 flags;				/* Flags */
+};
+
+static inline bool fscrypt_has_encryption_key(const struct inode *inode)
+{
+	return (inode->i_crypt_info != NULL);
+}
+
+static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
+{
+	return inode->i_sb->s_cop->dummy_context &&
+		inode->i_sb->s_cop->dummy_context(inode);
+}
+
 /* crypto.c */
-extern struct kmem_cache *fscrypt_info_cachep;
 extern struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *, gfp_t);
 extern void fscrypt_release_ctx(struct fscrypt_ctx *);
 extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *,
@@ -19,6 +65,12 @@ extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *,
 						u64, gfp_t);
 extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int,
 				unsigned int, u64);
+
+static inline struct page *fscrypt_control_page(struct page *page)
+{
+	return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
+}
+
 extern void fscrypt_restore_control_page(struct page *);
 
 extern const struct dentry_operations fscrypt_d_ops;
@@ -54,14 +106,11 @@ static inline void fscrypt_free_filename(struct fscrypt_name *fname)
 	kfree(fname->crypto_buf.name);
 }
 
-extern u32 fscrypt_fname_encrypted_size(const struct inode *, u32);
 extern int fscrypt_fname_alloc_buffer(const struct inode *, u32,
 				struct fscrypt_str *);
 extern void fscrypt_fname_free_buffer(struct fscrypt_str *);
 extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32,
 			const struct fscrypt_str *, struct fscrypt_str *);
-extern int fscrypt_fname_usr_to_disk(struct inode *, const struct qstr *,
-			struct fscrypt_str *);
 
 #define FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE	32
 
@@ -152,5 +201,13 @@ extern int __fscrypt_prepare_rename(struct inode *old_dir,
 				    struct dentry *new_dentry,
 				    unsigned int flags);
 extern int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry);
+extern int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len,
+				     unsigned int max_len,
+				     struct fscrypt_str *disk_link);
+extern int __fscrypt_encrypt_symlink(struct inode *inode, const char *target,
+				     unsigned int len,
+				     struct fscrypt_str *disk_link);
+extern void *fscrypt_get_symlink(struct inode *inode, const void *caddr,
+				       unsigned int max_size);
 
 #endif	/* _LINUX_FSCRYPT_SUPP_H */