| Message ID | 20181024195837.35532-3-olga.kornievskaia@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/1] man-page: copy_file_range(2) allow for cross-device copies | expand |
On Wed, Oct 24, 2018 at 10:59 PM Olga Kornievskaia <olga.kornievskaia@gmail.com> wrote: > > From: Olga Kornievskaia <kolga@netapp.com> > > 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 is no longer a possible error. > > Signed-off-by: Olga Kornievskaia <kolga@netapp.com> > --- > man2/copy_file_range.2 | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2 > index 20374ab..723b2d0 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. Since 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 > @@ -128,10 +129,6 @@ Out of memory. > .B ENOSPC > There is not enough space on the target filesystem to complete the copy. > .TP > -.B EXDEV > -The files referred to by > -.IR file_in " and " file_out > -are not on the same mounted filesystem. Man page serves users of old kernels as well. You should not delete this expected error, but you can add "... and kernel does not support cross filesystem copy". Thanks, Amir.
On Thu, Oct 25, 2018 at 12:28 AM Amir Goldstein <amir73il@gmail.com> wrote: > > On Wed, Oct 24, 2018 at 10:59 PM Olga Kornievskaia > <olga.kornievskaia@gmail.com> wrote: > > > > From: Olga Kornievskaia <kolga@netapp.com> > > > > 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 is no longer a possible error. > > > > Signed-off-by: Olga Kornievskaia <kolga@netapp.com> > > --- > > man2/copy_file_range.2 | 7 ++----- > > 1 file changed, 2 insertions(+), 5 deletions(-) > > > > diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2 > > index 20374ab..723b2d0 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. Since 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 > > @@ -128,10 +129,6 @@ Out of memory. > > .B ENOSPC > > There is not enough space on the target filesystem to complete the copy. > > .TP > > -.B EXDEV > > -The files referred to by > > -.IR file_in " and " file_out > > -are not on the same mounted filesystem. > > Man page serves users of old kernels as well. You should not delete this > expected error, but you can add "... and kernel does not support cross > filesystem copy". Thank you, will do. > > Thanks, > Amir.
On Thu, Oct 25, 2018 at 07:28:10AM +0300, Amir Goldstein wrote: > On Wed, Oct 24, 2018 at 10:59 PM Olga Kornievskaia > <olga.kornievskaia@gmail.com> wrote: > > > > From: Olga Kornievskaia <kolga@netapp.com> > > > > 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 is no longer a possible error. > > > > Signed-off-by: Olga Kornievskaia <kolga@netapp.com> > > --- > > man2/copy_file_range.2 | 7 ++----- > > 1 file changed, 2 insertions(+), 5 deletions(-) > > > > diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2 > > index 20374ab..723b2d0 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. Since 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 > > @@ -128,10 +129,6 @@ Out of memory. > > .B ENOSPC > > There is not enough space on the target filesystem to complete the copy. > > .TP > > -.B EXDEV > > -The files referred to by > > -.IR file_in " and " file_out > > -are not on the same mounted filesystem. > > Man page serves users of old kernels as well. You should not delete this > expected error, but you can add "... and kernel does not support cross > filesystem copy". I'd rather see this worded as: .B EXDEV The files referred to by .IR file_in " and " file_out -are not on the same mounted filesystem. +cannot be copied due to being on incompatible filesystems
On Thu, Oct 25, 2018 at 1:24 PM Matthew Wilcox <willy@infradead.org> wrote: > > On Thu, Oct 25, 2018 at 07:28:10AM +0300, Amir Goldstein wrote: > > On Wed, Oct 24, 2018 at 10:59 PM Olga Kornievskaia > > <olga.kornievskaia@gmail.com> wrote: > > > > > > From: Olga Kornievskaia <kolga@netapp.com> > > > > > > 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 is no longer a possible error. > > > > > > Signed-off-by: Olga Kornievskaia <kolga@netapp.com> > > > --- > > > man2/copy_file_range.2 | 7 ++----- > > > 1 file changed, 2 insertions(+), 5 deletions(-) > > > > > > diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2 > > > index 20374ab..723b2d0 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. Since 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 > > > @@ -128,10 +129,6 @@ Out of memory. > > > .B ENOSPC > > > There is not enough space on the target filesystem to complete the copy. > > > .TP > > > -.B EXDEV > > > -The files referred to by > > > -.IR file_in " and " file_out > > > -are not on the same mounted filesystem. > > > > Man page serves users of old kernels as well. You should not delete this > > expected error, but you can add "... and kernel does not support cross > > filesystem copy". > > I'd rather see this worded as: > > .B EXDEV > The files referred to by > .IR file_in " and " file_out > -are not on the same mounted filesystem. > +cannot be copied due to being on incompatible filesystems Why should this be changed to "incompatible filesystems". Existing code doesn't support not only incompatibly filesystem but also cross device of compatible file systems. And this error is only left for the old kernels. In the new kernel, the error EXDEV will never be returned.
On Thu, Oct 25, 2018 at 01:47:21PM -0400, Olga Kornievskaia wrote: > On Thu, Oct 25, 2018 at 1:24 PM Matthew Wilcox <willy@infradead.org> wrote: > > > > On Thu, Oct 25, 2018 at 07:28:10AM +0300, Amir Goldstein wrote: > > > On Wed, Oct 24, 2018 at 10:59 PM Olga Kornievskaia > > > <olga.kornievskaia@gmail.com> wrote: > > > > > > > > From: Olga Kornievskaia <kolga@netapp.com> > > > > > > > > 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 is no longer a possible error. > > > > > > > > Signed-off-by: Olga Kornievskaia <kolga@netapp.com> > > > > --- > > > > man2/copy_file_range.2 | 7 ++----- > > > > 1 file changed, 2 insertions(+), 5 deletions(-) > > > > > > > > diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2 > > > > index 20374ab..723b2d0 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. Since 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 > > > > @@ -128,10 +129,6 @@ Out of memory. > > > > .B ENOSPC > > > > There is not enough space on the target filesystem to complete the copy. > > > > .TP > > > > -.B EXDEV > > > > -The files referred to by > > > > -.IR file_in " and " file_out > > > > -are not on the same mounted filesystem. > > > > > > Man page serves users of old kernels as well. You should not delete this > > > expected error, but you can add "... and kernel does not support cross > > > filesystem copy". > > > > I'd rather see this worded as: > > > > .B EXDEV > > The files referred to by > > .IR file_in " and " file_out > > -are not on the same mounted filesystem. > > +cannot be copied due to being on incompatible filesystems > > Why should this be changed to "incompatible filesystems". Existing > code doesn't support not only incompatibly filesystem but also cross > device of compatible file systems. And this error is only left for the > old kernels. In the new kernel, the error EXDEV will never be > returned. If I try to copy_file_range() between an NFS filesystem and a CIFS filesystem with a new kernel, what error do I get?
On Thu, Oct 25, 2018 at 2:08 PM Matthew Wilcox <willy@infradead.org> wrote: > > On Thu, Oct 25, 2018 at 01:47:21PM -0400, Olga Kornievskaia wrote: > > On Thu, Oct 25, 2018 at 1:24 PM Matthew Wilcox <willy@infradead.org> wrote: > > > > > > On Thu, Oct 25, 2018 at 07:28:10AM +0300, Amir Goldstein wrote: > > > > On Wed, Oct 24, 2018 at 10:59 PM Olga Kornievskaia > > > > <olga.kornievskaia@gmail.com> wrote: > > > > > > > > > > From: Olga Kornievskaia <kolga@netapp.com> > > > > > > > > > > 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 is no longer a possible error. > > > > > > > > > > Signed-off-by: Olga Kornievskaia <kolga@netapp.com> > > > > > --- > > > > > man2/copy_file_range.2 | 7 ++----- > > > > > 1 file changed, 2 insertions(+), 5 deletions(-) > > > > > > > > > > diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2 > > > > > index 20374ab..723b2d0 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. Since 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 > > > > > @@ -128,10 +129,6 @@ Out of memory. > > > > > .B ENOSPC > > > > > There is not enough space on the target filesystem to complete the copy. > > > > > .TP > > > > > -.B EXDEV > > > > > -The files referred to by > > > > > -.IR file_in " and " file_out > > > > > -are not on the same mounted filesystem. > > > > > > > > Man page serves users of old kernels as well. You should not delete this > > > > expected error, but you can add "... and kernel does not support cross > > > > filesystem copy". > > > > > > I'd rather see this worded as: > > > > > > .B EXDEV > > > The files referred to by > > > .IR file_in " and " file_out > > > -are not on the same mounted filesystem. > > > +cannot be copied due to being on incompatible filesystems > > > > Why should this be changed to "incompatible filesystems". Existing > > code doesn't support not only incompatibly filesystem but also cross > > device of compatible file systems. And this error is only left for the > > old kernels. In the new kernel, the error EXDEV will never be > > returned. > > If I try to copy_file_range() between an NFS filesystem and a CIFS > filesystem with a new kernel, what error do I get? It is my understanding that you will not get an error instead a do_splice_direct() will do that copy.
diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2 index 20374ab..723b2d0 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. Since 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 @@ -128,10 +129,6 @@ Out of memory. .B ENOSPC There is not enough space on the target filesystem to complete the copy. .TP -.B EXDEV -The files referred to by -.IR file_in " and " file_out -are not on the same mounted filesystem. .SH VERSIONS The .BR copy_file_range ()