+#
+# LC_VFS_UNLINK_3ARGS
+#
+# 3.13 has vfs_unlink with 3 args
+#
+AC_DEFUN([LC_VFS_UNLINK_3ARGS], [
+LB_CHECK_COMPILE([if Linux kernel has 'vfs_unlink' with 3 args],
+vfs_unlink_3args, [
+ #include <linux/fs.h>
+],[
+ vfs_unlink(NULL, NULL, NULL);
+], [
+ AC_DEFINE(HAVE_VFS_UNLINK_3ARGS, 1,
+ [kernel has vfs_unlink with 3 args])
+])
+]) # LC_VFS_UNLINK_3ARGS
+
+#
+# LC_HAVE_BVEC_ITER
+#
+# 3.14 move some of its data in struct bio into the new
+# struct bvec_iter
+#
+AC_DEFUN([LC_HAVE_BVEC_ITER], [
+LB_CHECK_COMPILE([if Linux kernel has struct bvec_iter],
+have_bvec_iter, [
+ #include <linux/bio.h>
+],[
+ struct bvec_iter iter;
+ iter.bi_bvec_done = 0;
+], [
+ AC_DEFINE(HAVE_BVEC_ITER, 1,
+ [kernel has struct bvec_iter])
+])
+]) # LC_HAVE_BVEC_ITER
+
+#
+# LC_HAVE_TRUNCATE_IPAGE_FINAL
+#
+# 3.14 bring truncate_inode_pages_final for evict_inode
+#
+AC_DEFUN([LC_HAVE_TRUNCATE_IPAGES_FINAL], [
+LB_CHECK_COMPILE([if Linux kernel has truncate_inode_pages_final],
+truncate_ipages_final, [
+ #include <linux/mm.h>
+],[
+ truncate_inode_pages_final(NULL);
+], [
+ AC_DEFINE(HAVE_TRUNCATE_INODE_PAGES_FINAL, 1,
+ [kernel has truncate_inode_pages_final])
+])
+]) # LC_HAVE_TRUNCATE_IPAGES_FINAL
+
+#
+# LC_VFS_RENAME_6ARGS
+#
+# 3.15 has vfs_rename with 6 args
+#
+AC_DEFUN([LC_VFS_RENAME_6ARGS], [
+LB_CHECK_COMPILE([if Linux kernel has 'vfs_rename' with 6 args],
+vfs_rename_6args, [
+ #include <linux/fs.h>
+],[
+ vfs_rename(NULL, NULL, NULL, NULL, NULL, NULL);
+], [
+ AC_DEFINE(HAVE_VFS_RENAME_6ARGS, 1,
+ [kernel has vfs_rename with 6 args])
+])
+]) # LC_VFS_RENAME_6ARGS
+
+#
+# LC_DIRECTIO_USE_ITER
+#
+# 3.16 kernel changes direct IO to use iov_iter
+#
+AC_DEFUN([LC_DIRECTIO_USE_ITER], [
+LB_CHECK_COMPILE([if direct IO uses iov_iter],
+direct_io_iter, [
+ #include <linux/fs.h>
+],[
+ struct address_space_operations ops;
+ struct iov_iter *iter = NULL;
+ loff_t offset = 0;
+
+ ops.direct_IO(0, NULL, iter, offset);
+],[
+ AC_DEFINE(HAVE_DIRECTIO_ITER, 1,
+ [direct IO uses iov_iter])
+])
+]) # LC_DIRECTIO_USE_ITER
+
+#
+# LC_HAVE_IOV_ITER_INIT_DIRECTION
+#
+#
+# 3.16 linux commit 71d8e532b1549a478e6a6a8a44f309d050294d00
+# changed iov_iter_init api to start accepting a tag
+# that defines if its a read or write operation
+#
+AC_DEFUN([LC_HAVE_IOV_ITER_INIT_DIRECTION], [
+tmp_flags="$EXTRA_KCFLAGS"
+EXTRA_KCFLAGS="-Werror"
+LB_CHECK_COMPILE([if 'iov_iter_init' takes a tag],
+iter_init, [
+ #include <linux/uio.h>
+ #include <linux/fs.h>
+],[
+ const struct iovec *iov = NULL;
+
+ iov_iter_init(NULL, READ, iov, 1, 0);
+],[
+ AC_DEFINE(HAVE_IOV_ITER_INIT_DIRECTION, 1,
+ [iov_iter_init handles directional tag])
+])
+EXTRA_KCFLAGS="$tmp_flags"
+]) # LC_HAVE_IOV_ITER_INIT_DIRECTION
+
+#
+# LC_HAVE_FILE_OPERATIONS_READ_WRITE_ITER
+#
+# 3.16 introduces [read|write]_iter to struct file_operations
+#
+AC_DEFUN([LC_HAVE_FILE_OPERATIONS_READ_WRITE_ITER], [
+LB_CHECK_COMPILE([if 'file_operations.[read|write]_iter' exist],
+file_function_iter, [
+ #include <linux/fs.h>
+],[
+ ((struct file_operations *)NULL)->read_iter(NULL, NULL);
+ ((struct file_operations *)NULL)->write_iter(NULL, NULL);
+],[
+ AC_DEFINE(HAVE_FILE_OPERATIONS_READ_WRITE_ITER, 1,
+ [file_operations.[read|write]_iter functions exist])
+])
+]) # LC_HAVE_FILE_OPERATIONS_READ_WRITE_ITER
+
+#
+# LC_KEY_MATCH_DATA
+#
+# 3.17 replaces key_type::match with match_preparse
+# and has new struct key_match_data
+#
+AC_DEFUN([LC_KEY_MATCH_DATA], [
+LB_CHECK_COMPILE([if struct key_match field exist],
+key_match, [
+ #include <linux/key-type.h>
+],[
+ struct key_match_data data;
+],[
+ AC_DEFINE(HAVE_KEY_MATCH_DATA, 1,
+ [struct key_match_data exist])
+])
+]) # LC_KEY_MATCH_DATA
+
+#
+# LC_NFS_FILLDIR_USE_CTX
+#
+# 3.18 kernel moved from void cookie to struct dir_context
+#
+AC_DEFUN([LC_NFS_FILLDIR_USE_CTX], [
+tmp_flags="$EXTRA_KCFLAGS"
+EXTRA_KCFLAGS="-Werror"
+LB_CHECK_COMPILE([if filldir_t uses struct dir_context],
+filldir_ctx, [
+ #include <linux/fs.h>
+],[
+ int filldir(struct dir_context *ctx, const char* name,
+ int i, loff_t off, u64 tmp, unsigned temp)
+ {
+ return 0;
+ }
+
+ struct dir_context ctx = {
+ .actor = filldir,
+ };
+
+ ctx.actor(NULL, "test", 0, (loff_t) 0, 0, 0);
+],[
+ AC_DEFINE(HAVE_FILLDIR_USE_CTX, 1,
+ [filldir_t needs struct dir_context as argument])
+])
+EXTRA_KCFLAGS="$tmp_flags"
+]) # LC_NFS_FILLDIR_USE_CTX
+
+#
+# LC_KIOCB_HAS_NBYTES
+#
+# 3.19 kernel removed ki_nbytes from struct kiocb
+#
+AC_DEFUN([LC_KIOCB_HAS_NBYTES], [
+LB_CHECK_COMPILE([if struct kiocb has ki_nbytes field],
+ki_nbytes, [
+ #include <linux/fs.h>
+],[
+ struct kiocb iocb;
+
+ iocb.ki_nbytes = 0;
+],[
+ AC_DEFINE(HAVE_KI_NBYTES, 1, [ki_nbytes field exist])
+])
+]) # LC_KIOCB_HAS_NBYTES
+
+#
+# LC_BACKING_DEV_INFO_REMOVAL
+#
+# 3.20 kernel removed backing_dev_info from address_space
+#
+AC_DEFUN([LC_BACKING_DEV_INFO_REMOVAL], [
+LB_CHECK_COMPILE([if struct address_space has backing_dev_info],
+backing_dev_info, [
+ #include <linux/fs.h>
+],[
+ struct address_space mapping;
+
+ mapping.backing_dev_info = NULL;
+],[
+ AC_DEFINE(HAVE_BACKING_DEV_INFO, 1, [backing_dev_info exist])
+])
+]) # LC_BACKING_DEV_INFO_REMOVAL
+
+#
+# LC_HAVE_BDI_CAP_MAP_COPY
+#
+# 3.20 removed mmap handling for backing devices since
+# it breaks on non-MMU systems. See kernel commit
+# b4caecd48005fbed3949dde6c1cb233142fd69e9
+#
+AC_DEFUN([LC_HAVE_BDI_CAP_MAP_COPY], [
+LB_CHECK_COMPILE([if have 'BDI_CAP_MAP_COPY'],
+bdi_cap_map_copy, [
+ #include <linux/backing-dev.h>
+],[
+ struct backing_dev_info info;
+
+ info.capabilities = BDI_CAP_MAP_COPY;
+],[
+ AC_DEFINE(HAVE_BDI_CAP_MAP_COPY, 1,
+ [BDI_CAP_MAP_COPY exist])
+])
+]) # LC_HAVE_BDI_CAP_MAP_COPY
+
+#
+# LC_CANCEL_DIRTY_PAGE
+#
+# 4.0.0 kernel removed cancel_dirty_page
+#
+AC_DEFUN([LC_CANCEL_DIRTY_PAGE], [
+LB_CHECK_COMPILE([if cancel_dirty_page still exist],
+cancel_dirty_page, [
+ #include <linux/mm.h>
+],[
+ cancel_dirty_page(NULL, PAGE_SIZE);
+],[
+ AC_DEFINE(HAVE_CANCEL_DIRTY_PAGE, 1,
+ [cancel_dirty_page is still available])
+])
+]) # LC_CANCEL_DIRTY_PAGE
+
+#
+# LC_IOV_ITER_RW
+#
+# 4.1 kernel has iov_iter_rw
+#
+AC_DEFUN([LC_IOV_ITER_RW], [
+LB_CHECK_COMPILE([if iov_iter_rw exist],
+iov_iter_rw, [
+ #include <linux/fs.h>
+ #include <linux/uio.h>
+],[
+ struct iov_iter *iter = NULL;
+
+ iov_iter_rw(iter);
+],[
+ AC_DEFINE(HAVE_IOV_ITER_RW, 1,
+ [iov_iter_rw exist])
+])
+]) # LC_IOV_ITER_RW
+
+#
+# LC_HAVE_SYNC_READ_WRITE
+#
+# 4.1 new_sync_[read|write] no longer exported
+#
+AC_DEFUN([LC_HAVE_SYNC_READ_WRITE], [
+LB_CHECK_EXPORT([new_sync_read], [fs/read_write.c],
+ [AC_DEFINE(HAVE_SYNC_READ_WRITE, 1,
+ [new_sync_[read|write] is exported by the kernel])])
+]) # LC_HAVE_SYNC_READ_WRITE
+
+#
+# LC_NEW_CANCEL_DIRTY_PAGE
+#
+# 4.2 kernel has new cancel_dirty_page
+#
+AC_DEFUN([LC_NEW_CANCEL_DIRTY_PAGE], [
+LB_CHECK_COMPILE([if cancel_dirty_page with one argument exist],
+new_cancel_dirty_page, [
+ #include <linux/mm.h>
+],[
+ cancel_dirty_page(NULL);
+],[
+ AC_DEFINE(HAVE_NEW_CANCEL_DIRTY_PAGE, 1,
+ [cancel_dirty_page with one arguement is available])
+])
+]) # LC_NEW_CANCEL_DIRTY_PAGE