On Fri, Oct 26, 2018 at 04:10:47PM -0400, Olga Kornievskaia wrote: > From: Olga Kornievskaia <kolga@xxxxxxxxxx> > > A proposed VFS change removes the check for the files to reside > under the same file system. Instead, a file system driver implementation > is allowed to perform a cross-device copy_file_range() and if > the file system fails to support it instead fallback to doing > a do_splice copy. Therefore, EXDEV error code only applies to > kernel version prior to such support. > > Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx> > --- > man2/copy_file_range.2 | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2 > index 20374ab..88b40bb 100644 > --- a/man2/copy_file_range.2 > +++ b/man2/copy_file_range.2 > @@ -39,7 +39,8 @@ The > .BR copy_file_range () > system call performs an in-kernel copy between two file descriptors > without the additional cost of transferring data from the kernel to user space > -and then back into the kernel. > +and then back into the kernel. Starting kernel version 4.21 passed in > +file descriptors are not required to be under the same mounted file system. > It copies up to > .I len > bytes of data from file descriptor > @@ -131,7 +132,8 @@ There is not enough space on the target filesystem to complete the copy. > .B EXDEV > The files referred to by > .IR file_in " and " file_out > -are not on the same mounted filesystem. > +are not on the same mounted filesystem when the kernel does not support > +cross device file copy. Kernel can support cross device file copy, the filesystem may not. EXDEV One of the files specified by file_in and file_out are on a filesystem that does not support cross device copies. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
