freebsd-dev/config/kernel-rename.m4
Aleksa Sarai dbf6108b4d zfs_rename: support RENAME_* flags
Implement support for Linux's RENAME_* flags (for renameat2). Aside from
being quite useful for userspace (providing race-free ways to exchange
paths and implement mv --no-clobber), they are used by overlayfs and are
thus required in order to use overlayfs-on-ZFS.

In order for us to represent the new renameat2(2) flags in the ZIL, we
create two new transaction types for the two flags which need
transactional-level support (RENAME_EXCHANGE and RENAME_WHITEOUT).
RENAME_NOREPLACE does not need any ZIL support because we know that if
the operation succeeded before creating the ZIL entry, there was no file
to be clobbered and thus it can be treated as a regular TX_RENAME.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Pavel Snajdr <snajpa@snajpa.net>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Closes #12209
Closes #14070
2022-10-28 09:49:20 -07:00

112 lines
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AC_DEFUN([ZFS_AC_KERNEL_SRC_RENAME], [
dnl #
dnl # 3.9 (to 4.9) API change,
dnl #
dnl # A new version of iops->rename() was added (rename2) that takes a flag
dnl # argument (to support renameat2). However this separate function was
dnl # merged back into iops->rename() in Linux 4.9.
dnl #
ZFS_LINUX_TEST_SRC([inode_operations_rename2], [
#include <linux/fs.h>
int rename2_fn(struct inode *sip, struct dentry *sdp,
struct inode *tip, struct dentry *tdp,
unsigned int flags) { return 0; }
static const struct inode_operations
iops __attribute__ ((unused)) = {
.rename2 = rename2_fn,
};
],[])
dnl #
dnl # 4.9 API change,
dnl #
dnl # iops->rename2() merged into iops->rename(), and iops->rename() now
dnl # wants flags.
dnl #
ZFS_LINUX_TEST_SRC([inode_operations_rename_flags], [
#include <linux/fs.h>
int rename_fn(struct inode *sip, struct dentry *sdp,
struct inode *tip, struct dentry *tdp,
unsigned int flags) { return 0; }
static const struct inode_operations
iops __attribute__ ((unused)) = {
.rename = rename_fn,
};
],[])
dnl #
dnl # EL7 compatibility
dnl #
dnl # EL7 has backported renameat2 support, but it's done by defining a
dnl # separate iops wrapper structure that takes the .renameat2 function.
dnl #
ZFS_LINUX_TEST_SRC([dir_inode_operations_wrapper_rename2], [
#include <linux/fs.h>
int rename2_fn(struct inode *sip, struct dentry *sdp,
struct inode *tip, struct dentry *tdp,
unsigned int flags) { return 0; }
static const struct inode_operations_wrapper
iops __attribute__ ((unused)) = {
.rename2 = rename2_fn,
};
],[])
dnl #
dnl # 5.12 API change,
dnl #
dnl # Linux 5.12 introduced passing struct user_namespace* as the first
dnl # argument of the rename() and other inode_operations members.
dnl #
ZFS_LINUX_TEST_SRC([inode_operations_rename_userns], [
#include <linux/fs.h>
int rename_fn(struct user_namespace *user_ns, struct inode *sip,
struct dentry *sdp, struct inode *tip, struct dentry *tdp,
unsigned int flags) { return 0; }
static const struct inode_operations
iops __attribute__ ((unused)) = {
.rename = rename_fn,
};
],[])
])
AC_DEFUN([ZFS_AC_KERNEL_RENAME], [
AC_MSG_CHECKING([whether iops->rename() takes struct user_namespace*])
ZFS_LINUX_TEST_RESULT([inode_operations_rename_userns], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_IOPS_RENAME_USERNS, 1,
[iops->rename() takes struct user_namespace*])
],[
AC_MSG_RESULT(no)
AC_MSG_CHECKING([whether iops->rename2() exists])
ZFS_LINUX_TEST_RESULT([inode_operations_rename2], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_RENAME2, 1, [iops->rename2() exists])
],[
AC_MSG_RESULT(no)
AC_MSG_CHECKING([whether iops->rename() wants flags])
ZFS_LINUX_TEST_RESULT([inode_operations_rename_flags], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_RENAME_WANTS_FLAGS, 1,
[iops->rename() wants flags])
],[
AC_MSG_RESULT(no)
AC_MSG_CHECKING([whether struct inode_operations_wrapper takes .rename2()])
ZFS_LINUX_TEST_RESULT([dir_inode_operations_wrapper_rename2], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_RENAME2_OPERATIONS_WRAPPER, 1,
[struct inode_operations_wrapper takes .rename2()])
],[
AC_MSG_RESULT(no)
])
])
])
])
])