mirror_zfs/config/kernel-clear-inode.m4
Richard Yao 739a1a82e0 Linux 3.5 compat, end_writeback() changed to clear_inode()
The end_writeback() function was changed by moving the call to
inode_sync_wait() earlier in to evict().   This effecitvely changes
the ordering of the sync but it does not impact the details of
the zfs implementation.

However, as part of this change end_writeback() was renamed to
clear_inode() to reflect the new semantics.  This change does
impact us and clear_inode() now maps to end_writeback() for
kernels prior to 3.5.

Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #784
2012-07-23 12:29:36 -07:00

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dnl #
dnl # 3.5.0 API change
dnl # torvalds/linux@dbd5768f87ff6fb0a4fe09c4d7b6c4a24de99430 and
dnl # torvalds/linux@7994e6f7254354e03028a11f98a27bd67dace9f1 reworked
dnl # where inode_sync_wait() is called.
dnl #
dnl # Prior to these changes it would occur in end_writeback() but due
dnl # to various issues (described in the above commits) it has been
dnl # moved to evict(). This changes the ordering is which sync occurs
dnl # but otherwise doesn't impact the zpl implementation.
dnl #
dnl # The major impact here is the renaming of end_writeback() to
dnl # clear_inode(). However, care must be taken when detecting this
dnl # API change because as recently as 2.6.35 there was a clear_inode()
dnl # function. However, it was made obsolete by the evict_inode() API
dnl # change at the same time.
dnl #
dnl # Therefore, to ensure we have the correct API we only allow the
dnl # clear_inode() compatibility code to be defined iff the evict_inode()
dnl # functionality is also detected.
dnl #
AC_DEFUN([ZFS_AC_KERNEL_CLEAR_INODE], [
ZFS_CHECK_SYMBOL_EXPORT(
[clear_inode],
[fs/inode.c],
[AC_DEFINE(HAVE_CLEAR_INODE, 1,
[clear_inode() is available])],
[])
])