On Wed, Nov 09, 2022 at 10:38:02AM -0800, Jeremy Allison via samba-technical wrote:
On Wed, Nov 09, 2022 at 11:32:30AM +0200, Amir Goldstein wrote:
On Tue, Nov 8, 2022 at 7:53 PM Jeremy Allison via samba-technical
<samba-technical@xxxxxxxxxxxxxxx> wrote:
On Mon, Nov 07, 2022 at 10:47:48PM -0800, Christoph Hellwig wrote:
On Mon, Nov 07, 2022 at 04:53:42PM -0800, Jeremy Allison via samba-technical wrote:
ret = ioctl(fsp_get_io_fd(dest_fsp), BTRFS_IOC_CLONE_RANGE, &cr_args);
what ioctls are used for this in XFS ?
We'd need a VFS module that implements them for XFS.
That ioctl is now implemented in the Linux VFS and supported by btrfs,
ocfs2, xfs, nfs (v4.2), cifs and overlayfs.
I'm assuming it's this:
https://man7.org/linux/man-pages/man2/ioctl_ficlonerange.2.html
Yeah ? I'll write some test code and see if I can get it
into the vfs_default code.
Looks like this was already discussed during the work on generic
implementation of FSCTL_SRV_COPYCHUNK:
https://bugzilla.samba.org/show_bug.cgi?id=12033#c3
Forgotten?
Yep :-).
Left for later?
So looks like we do copy_file_range(), but not CLONE_RANGE,
or rather CLONE_RANGE only in btrfs.
So the code change needed is to move the logic in vfs_btrfs.c
into vfs_default.c, and change the call in vfs_btrfs.c:btrfs_offload_write_send()
to SMB_VFS_NEXT_OFFLOAD_WRITE_SEND() to call the old fallback code
inside vfs_default.c (vfswrap_offload_write_send()).
Although looking at the current Linux kernel I find inside:
ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
size_t len, unsigned int flags)
{
https://github.com/torvalds/linux/blob/0adc313c4f20639f7e235b8d6719d96a2024cf91/fs/read_write.c#L1506
/*
* Try cloning first, this is supported by more file systems, and
* more efficient if both clone and copy are supported (e.g. NFS).
*/
if (file_in->f_op->remap_file_range &&
file_inode(file_in)->i_sb == file_inode(file_out)->i_sb) {
loff_t cloned;
cloned = file_in->f_op->remap_file_range(file_in, pos_in,
file_out, pos_out,
min_t(loff_t, MAX_RW_COUNT, len),
REMAP_FILE_CAN_SHORTEN);
if (cloned > 0) {
ret = cloned;
and looking at the code supporting int ioctl(int dest_fd, FICLONERANGE, struct file_clone_range *arg);
we have:
loff_t do_clone_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
loff_t len, unsigned int remap_flags)
...
ret = file_in->f_op->remap_file_range(file_in, pos_in,
file_out, pos_out, len, remap_flags);
So it *looks* like the copy_file_range() syscall will internally
call the equivalent of FICLONERANGE if the underlying file
system supports it.
So maybe the right fix is to remove the FICLONERANGE specific
code from our vfs_btrfs.c and just always use copy_file_range().
Any comments from other Samba Team members ?
Jeremy.
