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Linux 6.8 compat: use splice_copy_file_range() for fallback
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Linux 6.8 removes generic_copy_file_range(), which had been reduced to a
simple wrapper around splice_copy_file_range(). Detect that function
directly and use it if generic_ is not available.

Signed-off-by: Rob Norris <[email protected]>
Sponsored-by: https://despairlabs.com/sponsor/
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robn authored and darkbasic committed Mar 11, 2024
1 parent c883088 commit 97d694c
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Showing 3 changed files with 43 additions and 2 deletions.
27 changes: 27 additions & 0 deletions config/kernel-vfs-file_range.m4
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,9 @@ dnl #
dnl # 5.3: VFS copy_file_range() expected to do its own fallback,
dnl # generic_copy_file_range() added to support it
dnl #
dnl # 6.8: generic_copy_file_range() removed, replaced by
dnl # splice_copy_file_range()
dnl #
AC_DEFUN([ZFS_AC_KERNEL_SRC_VFS_COPY_FILE_RANGE], [
ZFS_LINUX_TEST_SRC([vfs_copy_file_range], [
#include <linux/fs.h>
Expand Down Expand Up @@ -72,6 +75,30 @@ AC_DEFUN([ZFS_AC_KERNEL_VFS_GENERIC_COPY_FILE_RANGE], [
])
])

AC_DEFUN([ZFS_AC_KERNEL_SRC_VFS_SPLICE_COPY_FILE_RANGE], [
ZFS_LINUX_TEST_SRC([splice_copy_file_range], [
#include <linux/splice.h>
], [
struct file *src_file __attribute__ ((unused)) = NULL;
loff_t src_off __attribute__ ((unused)) = 0;
struct file *dst_file __attribute__ ((unused)) = NULL;
loff_t dst_off __attribute__ ((unused)) = 0;
size_t len __attribute__ ((unused)) = 0;
splice_copy_file_range(src_file, src_off, dst_file, dst_off,
len);
])
])
AC_DEFUN([ZFS_AC_KERNEL_VFS_SPLICE_COPY_FILE_RANGE], [
AC_MSG_CHECKING([whether splice_copy_file_range() is available])
ZFS_LINUX_TEST_RESULT([splice_copy_file_range], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_VFS_SPLICE_COPY_FILE_RANGE, 1,
[splice_copy_file_range() is available])
],[
AC_MSG_RESULT(no)
])
])

AC_DEFUN([ZFS_AC_KERNEL_SRC_VFS_CLONE_FILE_RANGE], [
ZFS_LINUX_TEST_SRC([vfs_clone_file_range], [
#include <linux/fs.h>
Expand Down
2 changes: 2 additions & 0 deletions config/kernel.m4
Original file line number Diff line number Diff line change
Expand Up @@ -118,6 +118,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_SRC], [
ZFS_AC_KERNEL_SRC_VFS_IOV_ITER
ZFS_AC_KERNEL_SRC_VFS_COPY_FILE_RANGE
ZFS_AC_KERNEL_SRC_VFS_GENERIC_COPY_FILE_RANGE
ZFS_AC_KERNEL_SRC_VFS_SPLICE_COPY_FILE_RANGE
ZFS_AC_KERNEL_SRC_VFS_REMAP_FILE_RANGE
ZFS_AC_KERNEL_SRC_VFS_CLONE_FILE_RANGE
ZFS_AC_KERNEL_SRC_VFS_DEDUPE_FILE_RANGE
Expand Down Expand Up @@ -266,6 +267,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_RESULT], [
ZFS_AC_KERNEL_VFS_IOV_ITER
ZFS_AC_KERNEL_VFS_COPY_FILE_RANGE
ZFS_AC_KERNEL_VFS_GENERIC_COPY_FILE_RANGE
ZFS_AC_KERNEL_VFS_SPLICE_COPY_FILE_RANGE
ZFS_AC_KERNEL_VFS_REMAP_FILE_RANGE
ZFS_AC_KERNEL_VFS_CLONE_FILE_RANGE
ZFS_AC_KERNEL_VFS_DEDUPE_FILE_RANGE
Expand Down
16 changes: 14 additions & 2 deletions module/os/linux/zfs/zpl_file_range.c
Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,9 @@
#include <linux/compat.h>
#endif
#include <linux/fs.h>
#ifdef HAVE_VFS_SPLICE_COPY_FILE_RANGE
#include <linux/splice.h>
#endif
#include <sys/file.h>
#include <sys/zfs_znode.h>
#include <sys/zfs_vnops.h>
Expand Down Expand Up @@ -102,7 +105,7 @@ zpl_copy_file_range(struct file *src_file, loff_t src_off,
ret = zpl_clone_file_range_impl(src_file, src_off,
dst_file, dst_off, len);

#ifdef HAVE_VFS_GENERIC_COPY_FILE_RANGE
#if defined(HAVE_VFS_GENERIC_COPY_FILE_RANGE)
/*
* Since Linux 5.3 the filesystem driver is responsible for executing
* an appropriate fallback, and a generic fallback function is provided.
Expand All @@ -111,14 +114,23 @@ zpl_copy_file_range(struct file *src_file, loff_t src_off,
ret == -EAGAIN)
ret = generic_copy_file_range(src_file, src_off, dst_file,
dst_off, len, flags);
#elif defined(HAVE_VFS_SPLICE_COPY_FILE_RANGE)
/*
* Since 6.8 the fallback function is called splice_copy_file_range
* and has a slightly different signature.
*/
if (ret == -EOPNOTSUPP || ret == -EINVAL || ret == -EXDEV ||
ret == -EAGAIN)
ret = splice_copy_file_range(src_file, src_off, dst_file,
dst_off, len);
#else
/*
* Before Linux 5.3 the filesystem has to return -EOPNOTSUPP to signal
* to the kernel that it should fallback to a content copy.
*/
if (ret == -EINVAL || ret == -EXDEV || ret == -EAGAIN)
ret = -EOPNOTSUPP;
#endif /* HAVE_VFS_GENERIC_COPY_FILE_RANGE */
#endif /* HAVE_VFS_GENERIC_COPY_FILE_RANGE || HAVE_VFS_SPLICE_COPY_FILE_RANGE */

return (ret);
}
Expand Down

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