Introduce ZFS_LINUX_REQUIRE_API autoconf macro

Currently, if API tests fail, we either ignore the failures, or
unconditionally halt the kernel build.  This leads to situations where
incompatibilities with existing APIs may develop, but not trip the
configure compatibility checks.

This introduces a new mechanism to require APIs for kernels above a
particular version.  While not perfect, this at least guarantees
mainline kernels do not break existing APIs without at least providing
some warning.

Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Antonio Russo <aerusso@aerusso.net>
Closes #14343
This commit is contained in:
Antonio Russo 2023-01-04 21:41:16 -07:00 committed by Brian Behlendorf
parent d27c81847b
commit 556ed09537
2 changed files with 33 additions and 1 deletions

View File

@ -60,7 +60,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TMPFILE], [
AC_DEFINE(HAVE_TMPFILE, 1, [i_op->tmpfile() exists])
AC_DEFINE(HAVE_TMPFILE_DENTRY, 1, [i_op->tmpfile() uses old dentry signature])
],[
AC_MSG_RESULT(no)
ZFS_LINUX_REQUIRE_API([i_op->tmpfile()], [3.11])
])
])
])

View File

@ -958,3 +958,35 @@ AC_DEFUN([ZFS_LINUX_TRY_COMPILE_HEADER], [
[test -f build/conftest/conftest.ko], [$3], [$4], [$5])
])
])
dnl #
dnl # AS_VERSION_COMPARE_LE
dnl # like AS_VERSION_COMPARE_LE, but runs $3 if (and only if) $1 <= $2
dnl # AS_VERSION_COMPARE_LE (version-1, version-2, [action-if-less-or-equal], [action-if-greater])
dnl #
AC_DEFUN([AS_VERSION_COMPARE_LE], [
AS_VERSION_COMPARE([$1], [$2], [$3], [$3], [$4])
])
dnl #
dnl # ZFS_LINUX_REQUIRE_API
dnl # like ZFS_LINUX_TEST_ERROR, except only fails if the kernel is
dnl # at least some specified version.
dnl #
AC_DEFUN([ZFS_LINUX_REQUIRE_API], [
AS_VERSION_COMPARE_LE([$2], [$kernsrcver], [
AC_MSG_ERROR([
*** None of the expected "$1" interfaces were detected. This
*** interface is expected for kernels version "$2" and above.
*** This may be because your kernel version is newer than what is
*** supported, or you are using a patched custom kernel with
*** incompatible modifications. Newer kernels may have incompatible
*** APIs.
***
*** ZFS Version: $ZFS_META_ALIAS
*** Compatible Kernels: $ZFS_META_KVER_MIN - $ZFS_META_KVER_MAX
])
], [
AC_MSG_RESULT(no)
])
])