mirror_zfs/config/kernel-get-link.m4
Brian Behlendorf beeed4596b Linux 4.5 compat: get_link() / put_link()
The follow_link() interface was retired in favor of get_link().
In the process of phasing in get_link() the Linux kernel went
through two different versions.  The first of which depended
on put_link() and the final version on a delayed done function.

- Improved configure checks for .follow_link, .get_link, .put_link.
  - Interfaces checked from newest to oldest.
  - Strict checking for each possible known interface.
  - Configure fails when no known interface is available.

- Both versions .get_link are detected and supported as well
  two previous versions of .follow_link.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Issue #4228
2016-01-20 11:36:00 -08:00

101 lines
2.6 KiB
Plaintext

dnl #
dnl # Supported get_link() interfaces checked newest to oldest.
dnl #
AC_DEFUN([ZFS_AC_KERNEL_FOLLOW_LINK], [
dnl #
dnl # 4.2 API change
dnl # - This kernel retired the nameidata structure.
dnl #
AC_MSG_CHECKING([whether iops->follow_link() passes cookie])
ZFS_LINUX_TRY_COMPILE([
#include <linux/fs.h>
const char *follow_link(struct dentry *de,
void **cookie) { return "symlink"; }
static struct inode_operations
iops __attribute__ ((unused)) = {
.follow_link = follow_link,
};
],[
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_FOLLOW_LINK_COOKIE, 1,
[iops->follow_link() cookie])
],[
dnl #
dnl # 2.6.32 API
dnl #
AC_MSG_RESULT(no)
AC_MSG_CHECKING(
[whether iops->follow_link() passes nameidata])
ZFS_LINUX_TRY_COMPILE([
#include <linux/fs.h>
void *follow_link(struct dentry *de, struct
nameidata *nd) { return (void *)NULL; }
static struct inode_operations
iops __attribute__ ((unused)) = {
.follow_link = follow_link,
};
],[
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_FOLLOW_LINK_NAMEIDATA, 1,
[iops->follow_link() nameidata])
],[
AC_MSG_ERROR(no; please file a bug report)
])
])
])
AC_DEFUN([ZFS_AC_KERNEL_GET_LINK], [
dnl #
dnl # 4.5 API change
dnl # The get_link interface has added a delayed done call and
dnl # used it to retire the put_link() interface.
dnl #
AC_MSG_CHECKING([whether iops->get_link() passes delayed])
ZFS_LINUX_TRY_COMPILE([
#include <linux/fs.h>
const char *get_link(struct dentry *de, struct inode *ip,
struct delayed_call *done) { return "symlink"; }
static struct inode_operations
iops __attribute__ ((unused)) = {
.get_link = get_link,
};
],[
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_GET_LINK_DELAYED, 1,
[iops->get_link() delayed])
],[
dnl #
dnl # 4.5 API change
dnl # The follow_link() interface has been replaced by
dnl # get_link() which behaves the same as before except:
dnl # - An inode is passed as a separate argument
dnl # - When called in RCU mode a NULL dentry is passed.
dnl #
AC_MSG_RESULT(no)
AC_MSG_CHECKING([whether iops->get_link() passes cookie])
ZFS_LINUX_TRY_COMPILE([
#include <linux/fs.h>
const char *get_link(struct dentry *de, struct
inode *ip, void **cookie) { return "symlink"; }
static struct inode_operations
iops __attribute__ ((unused)) = {
.get_link = get_link,
};
],[
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_GET_LINK_COOKIE, 1,
[iops->get_link() cookie])
],[
dnl #
dnl # Check for the follow_link APIs.
dnl #
AC_MSG_RESULT(no)
ZFS_AC_KERNEL_FOLLOW_LINK
])
])
])