fscrypto: don't let data integrity writebacks fail with ENOMEM

This patch fixes the issue introduced by the ext4 crypto fix in a same manner.
For F2FS, however, we flush the pending IOs and wait for a while to acquire free
memory.

Fixes: c9af28fdd4492 ("ext4 crypto: don't let data integrity writebacks fail with ENOMEM")
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h
index cd91f75..6027f6b 100644
--- a/include/linux/fscrypto.h
+++ b/include/linux/fscrypto.h
@@ -263,9 +263,9 @@
 extern struct kmem_cache *fscrypt_info_cachep;
 int fscrypt_initialize(void);
 
-extern struct fscrypt_ctx *fscrypt_get_ctx(struct inode *);
+extern struct fscrypt_ctx *fscrypt_get_ctx(struct inode *, gfp_t);
 extern void fscrypt_release_ctx(struct fscrypt_ctx *);
-extern struct page *fscrypt_encrypt_page(struct inode *, struct page *);
+extern struct page *fscrypt_encrypt_page(struct inode *, struct page *, gfp_t);
 extern int fscrypt_decrypt_page(struct page *);
 extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
 extern void fscrypt_pullback_bio_page(struct page **, bool);
@@ -299,7 +299,8 @@
 #endif
 
 /* crypto.c */
-static inline struct fscrypt_ctx *fscrypt_notsupp_get_ctx(struct inode *i)
+static inline struct fscrypt_ctx *fscrypt_notsupp_get_ctx(struct inode *i,
+							gfp_t f)
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }
@@ -310,7 +311,7 @@
 }
 
 static inline struct page *fscrypt_notsupp_encrypt_page(struct inode *i,
-						struct page *p)
+						struct page *p, gfp_t f)
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }