#
# We try to detect the specific api incompatibilities with simple tests
# because distros regularly backport features without changing the
# version.
#

ccflags-y += -include $(src)/kernelcompat.h

#
# v3.10-rc6-21-gbb6f619b3a49
#
# _readdir changes from fop->readdir() to fop->iterate() and from
# filldir(dirent) to dir_emit(ctx).
#
ifneq (,$(shell grep 'iterate.*dir_context' include/linux/fs.h))
ccflags-y += -DKC_ITERATE_DIR_CONTEXT
endif

#
# v3.10-rc6-23-g5f99f4e79abc
#
# Helpers including dir_emit_dots() are added in the process of
# switching dcache_readdir() from fop->readdir() to fop->iterate()
#
ifneq (,$(shell grep 'dir_emit_dots' include/linux/fs.h))
ccflags-y += -DKC_DIR_EMIT_DOTS
endif

#
# v3.18-rc2-19-gb5ae6b15bd73
# 
# Folds d_materialise_unique into d_splice_alias. Note reversal
# of arguments (Also note Documentation/filesystems/porting.rst)
#
ifneq (,$(shell grep 'd_materialise_unique' include/linux/dcache.h))
ccflags-y += -DKC_D_MATERIALISE_UNIQUE=1
endif

#
# RHEL extended the fop struct so to use it we have to set
# a flag to indicate that the struct is large enough and
# contains the pointer.
#
ifneq (,$(shell grep 'FMODE_KABI_ITERATE' include/linux/fs.h))
ccflags-y += -DKC_FMODE_KABI_ITERATE
endif

#
# v4.7-rc2-23-g0d4d717f2583
#
# Added user_ns argument to posix_acl_valid
#
ifneq (,$(shell grep 'posix_acl_valid.*user_namespace' include/linux/posix_acl.h))
ccflags-y += -DKC_POSIX_ACL_VALID_USER_NS
endif

#
# v5.3-12296-g6d2052d188d9
#
# The RBCOMPUTE function is now passed an extra flag, and should return a bool
# to indicate whether the propagated callback should stop or not.
#
ifneq (,$(shell grep 'static inline bool RBNAME.*_compute_max' include/linux/rbtree_augmented.h))
ccflags-y += -DKC_RB_TREE_AUGMENTED_COMPUTE_MAX
endif

#
# v3.13-25-g37bc15392a23
#
# Renames posix_acl_create to __posix_acl_create and provide some
# new interfaces for creating ACLs
#
ifneq (,$(shell grep '__posix_acl_create' include/linux/posix_acl.h))
ccflags-y += -DKC___POSIX_ACL_CREATE
endif

#
# v4.8-rc1-29-g31051c85b5e2
#
# inode_change_ok() removed - replace with setattr_prepare()
#
ifneq (,$(shell grep 'extern int setattr_prepare' include/linux/fs.h))
ccflags-y += -DKC_SETATTR_PREPARE
endif

#
# v4.15-rc3-4-gae5e165d855d
#
# linux/iversion.h needs to manually be included for code that
# manipulates this field.
#
ifneq (,$(shell grep -s 'define _LINUX_IVERSION_H' include/linux/iversion.h))
ccflags-y += -DKC_NEED_LINUX_IVERSION_H=1
endif