linux-fsdevel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH] copy_file_range.2: Update cross-filesystem support for 5.12
       [not found] <20210509213930.94120-1-alx.manpages@gmail.com>
@ 2021-05-09 21:39 ` Alejandro Colomar
  2021-05-10  0:01   ` Michael Kerrisk (man-pages)
  0 siblings, 1 reply; 4+ messages in thread
From: Alejandro Colomar @ 2021-05-09 21:39 UTC (permalink / raw)
  To: mtk.manpages
  Cc: Alejandro Colomar, linux-man, Luis Henriques, Amir Goldstein,
	Greg KH, Anna Schumaker, Jeff Layton, Steve French,
	Miklos Szeredi, Trond Myklebust, Alexander Viro, Darrick J. Wong,
	Dave Chinner, Nicolas Boichat, Ian Lance Taylor, Luis Lozano,
	Andreas Dilger, Olga Kornievskaia, Christoph Hellwig, ceph-devel,
	linux-kernel, CIFS, samba-technical, linux-fsdevel,
	Linux NFS Mailing List, Walter Harms

Linux 5.12 fixes a regression.

Cross-filesystem (introduced in 5.3) copies were buggy.

Move the statements documenting cross-fs to BUGS.
Kernels 5.3..5.11 should be patched soon.

State version information for some errors related to this.

Reported-by: Luis Henriques <lhenriques@suse.de>
Reported-by: Amir Goldstein <amir73il@gmail.com>
Related: <https://lwn.net/Articles/846403/>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Steve French <sfrench@samba.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Nicolas Boichat <drinkcat@chromium.org>
Cc: Ian Lance Taylor <iant@google.com>
Cc: Luis Lozano <llozano@chromium.org>
Cc: Andreas Dilger <adilger@dilger.ca>
Cc: Olga Kornievskaia <aglo@umich.edu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: ceph-devel <ceph-devel@vger.kernel.org>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Cc: CIFS <linux-cifs@vger.kernel.org>
Cc: samba-technical <samba-technical@lists.samba.org>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>
Cc: Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Cc: Walter Harms <wharms@bfs.de>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
---
 man2/copy_file_range.2 | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2
index 467a16300..843e02241 100644
--- a/man2/copy_file_range.2
+++ b/man2/copy_file_range.2
@@ -169,6 +169,9 @@ Out of memory.
 .B ENOSPC
 There is not enough space on the target filesystem to complete the copy.
 .TP
+.BR EOPNOTSUPP " (since Linux 5.12)"
+The filesystem does not support this operation.
+.TP
 .B EOVERFLOW
 The requested source or destination range is too large to represent in the
 specified data types.
@@ -184,10 +187,17 @@ or
 .I fd_out
 refers to an active swap file.
 .TP
-.B EXDEV
+.BR EXDEV " (before Linux 5.3)"
+The files referred to by
+.IR fd_in " and " fd_out
+are not on the same filesystem.
+.TP
+.BR EXDEV " (since Linux 5.12)"
 The files referred to by
 .IR fd_in " and " fd_out
-are not on the same mounted filesystem (pre Linux 5.3).
+are not on the same filesystem,
+and the source and target filesystems are not of the same type,
+or do not support cross-filesystem copy.
 .SH VERSIONS
 The
 .BR copy_file_range ()
@@ -200,8 +210,11 @@ Areas of the API that weren't clearly defined were clarified and the API bounds
 are much more strictly checked than on earlier kernels.
 Applications should target the behaviour and requirements of 5.3 kernels.
 .PP
-First support for cross-filesystem copies was introduced in Linux 5.3.
-Older kernels will return -EXDEV when cross-filesystem copies are attempted.
+Since Linux 5.12,
+cross-filesystem copies can be achieved
+when both filesystems are of the same type,
+and that filesystem implements support for it.
+See BUGS for behavior prior to 5.12.
 .SH CONFORMING TO
 The
 .BR copy_file_range ()
@@ -226,6 +239,12 @@ gives filesystems an opportunity to implement "copy acceleration" techniques,
 such as the use of reflinks (i.e., two or more inodes that share
 pointers to the same copy-on-write disk blocks)
 or server-side-copy (in the case of NFS).
+.SH BUGS
+In Linux kernels 5.3 to 5.11,
+cross-filesystem copies were implemented by the kernel,
+if the operation was not supported by individual filesystems.
+However, on some virtual filesystems,
+the call failed to copy, while still reporting success.
 .SH EXAMPLES
 .EX
 #define _GNU_SOURCE
-- 
2.31.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] copy_file_range.2: Update cross-filesystem support for 5.12
  2021-05-09 21:39 ` [PATCH] copy_file_range.2: Update cross-filesystem support for 5.12 Alejandro Colomar
@ 2021-05-10  0:01   ` Michael Kerrisk (man-pages)
  2021-05-10  4:26     ` Amir Goldstein
  0 siblings, 1 reply; 4+ messages in thread
From: Michael Kerrisk (man-pages) @ 2021-05-10  0:01 UTC (permalink / raw)
  To: Alejandro Colomar
  Cc: mtk.manpages, linux-man, Luis Henriques, Amir Goldstein, Greg KH,
	Anna Schumaker, Jeff Layton, Steve French, Miklos Szeredi,
	Trond Myklebust, Alexander Viro, Darrick J. Wong, Dave Chinner,
	Nicolas Boichat, Ian Lance Taylor, Luis Lozano, Andreas Dilger,
	Olga Kornievskaia, Christoph Hellwig, ceph-devel, linux-kernel,
	CIFS, samba-technical, linux-fsdevel, Linux NFS Mailing List,
	Walter Harms

Hi Alex,

On 5/10/21 9:39 AM, Alejandro Colomar wrote:
> Linux 5.12 fixes a regression.
> 
> Cross-filesystem (introduced in 5.3) copies were buggy.
> 
> Move the statements documenting cross-fs to BUGS.
> Kernels 5.3..5.11 should be patched soon.
> 
> State version information for some errors related to this.

Thanks. Patch applied.

Cheers,

Michael

> 
> Reported-by: Luis Henriques <lhenriques@suse.de>
> Reported-by: Amir Goldstein <amir73il@gmail.com>
> Related: <https://lwn.net/Articles/846403/>
> Cc: Greg KH <gregkh@linuxfoundation.org>
> Cc: Michael Kerrisk <mtk.manpages@gmail.com>
> Cc: Anna Schumaker <anna.schumaker@netapp.com>
> Cc: Jeff Layton <jlayton@kernel.org>
> Cc: Steve French <sfrench@samba.org>
> Cc: Miklos Szeredi <miklos@szeredi.hu>
> Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
> Cc: Dave Chinner <dchinner@redhat.com>
> Cc: Nicolas Boichat <drinkcat@chromium.org>
> Cc: Ian Lance Taylor <iant@google.com>
> Cc: Luis Lozano <llozano@chromium.org>
> Cc: Andreas Dilger <adilger@dilger.ca>
> Cc: Olga Kornievskaia <aglo@umich.edu>
> Cc: Christoph Hellwig <hch@infradead.org>
> Cc: ceph-devel <ceph-devel@vger.kernel.org>
> Cc: linux-kernel <linux-kernel@vger.kernel.org>
> Cc: CIFS <linux-cifs@vger.kernel.org>
> Cc: samba-technical <samba-technical@lists.samba.org>
> Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>
> Cc: Linux NFS Mailing List <linux-nfs@vger.kernel.org>
> Cc: Walter Harms <wharms@bfs.de>
> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
> ---
>  man2/copy_file_range.2 | 27 +++++++++++++++++++++++----
>  1 file changed, 23 insertions(+), 4 deletions(-)
> 
> diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2
> index 467a16300..843e02241 100644
> --- a/man2/copy_file_range.2
> +++ b/man2/copy_file_range.2
> @@ -169,6 +169,9 @@ Out of memory.
>  .B ENOSPC
>  There is not enough space on the target filesystem to complete the copy.
>  .TP
> +.BR EOPNOTSUPP " (since Linux 5.12)"
> +The filesystem does not support this operation.
> +.TP
>  .B EOVERFLOW
>  The requested source or destination range is too large to represent in the
>  specified data types.
> @@ -184,10 +187,17 @@ or
>  .I fd_out
>  refers to an active swap file.
>  .TP
> -.B EXDEV
> +.BR EXDEV " (before Linux 5.3)"
> +The files referred to by
> +.IR fd_in " and " fd_out
> +are not on the same filesystem.
> +.TP
> +.BR EXDEV " (since Linux 5.12)"
>  The files referred to by
>  .IR fd_in " and " fd_out
> -are not on the same mounted filesystem (pre Linux 5.3).
> +are not on the same filesystem,
> +and the source and target filesystems are not of the same type,
> +or do not support cross-filesystem copy.
>  .SH VERSIONS
>  The
>  .BR copy_file_range ()
> @@ -200,8 +210,11 @@ Areas of the API that weren't clearly defined were clarified and the API bounds
>  are much more strictly checked than on earlier kernels.
>  Applications should target the behaviour and requirements of 5.3 kernels.
>  .PP
> -First support for cross-filesystem copies was introduced in Linux 5.3.
> -Older kernels will return -EXDEV when cross-filesystem copies are attempted.
> +Since Linux 5.12,
> +cross-filesystem copies can be achieved
> +when both filesystems are of the same type,
> +and that filesystem implements support for it.
> +See BUGS for behavior prior to 5.12.
>  .SH CONFORMING TO
>  The
>  .BR copy_file_range ()
> @@ -226,6 +239,12 @@ gives filesystems an opportunity to implement "copy acceleration" techniques,
>  such as the use of reflinks (i.e., two or more inodes that share
>  pointers to the same copy-on-write disk blocks)
>  or server-side-copy (in the case of NFS).
> +.SH BUGS
> +In Linux kernels 5.3 to 5.11,
> +cross-filesystem copies were implemented by the kernel,
> +if the operation was not supported by individual filesystems.
> +However, on some virtual filesystems,
> +the call failed to copy, while still reporting success.
>  .SH EXAMPLES
>  .EX
>  #define _GNU_SOURCE
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] copy_file_range.2: Update cross-filesystem support for 5.12
  2021-05-10  0:01   ` Michael Kerrisk (man-pages)
@ 2021-05-10  4:26     ` Amir Goldstein
  2021-05-10 16:34       ` Michael Kerrisk (man-pages)
  0 siblings, 1 reply; 4+ messages in thread
From: Amir Goldstein @ 2021-05-10  4:26 UTC (permalink / raw)
  To: Michael Kerrisk (man-pages)
  Cc: Alejandro Colomar, linux-man, Luis Henriques, Greg KH,
	Anna Schumaker, Jeff Layton, Steve French, Miklos Szeredi,
	Trond Myklebust, Alexander Viro, Darrick J. Wong, Dave Chinner,
	Nicolas Boichat, Ian Lance Taylor, Luis Lozano, Andreas Dilger,
	Olga Kornievskaia, Christoph Hellwig, ceph-devel, linux-kernel,
	CIFS, samba-technical, linux-fsdevel, Linux NFS Mailing List,
	Walter Harms

On Mon, May 10, 2021 at 3:01 AM Michael Kerrisk (man-pages)
<mtk.manpages@gmail.com> wrote:
>
> Hi Alex,
>
> On 5/10/21 9:39 AM, Alejandro Colomar wrote:
> > Linux 5.12 fixes a regression.

Nope.
That never happened:
https://lore.kernel.org/linux-fsdevel/8735v4tcye.fsf@suse.de/

> >
> > Cross-filesystem (introduced in 5.3) copies were buggy.
> >
> > Move the statements documenting cross-fs to BUGS.
> > Kernels 5.3..5.11 should be patched soon.
> >
> > State version information for some errors related to this.
>
> Thanks. Patch applied.

I guess that would need to be reverted...

Thanks,
Amir.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] copy_file_range.2: Update cross-filesystem support for 5.12
  2021-05-10  4:26     ` Amir Goldstein
@ 2021-05-10 16:34       ` Michael Kerrisk (man-pages)
  0 siblings, 0 replies; 4+ messages in thread
From: Michael Kerrisk (man-pages) @ 2021-05-10 16:34 UTC (permalink / raw)
  To: Amir Goldstein
  Cc: mtk.manpages, Alejandro Colomar, linux-man, Luis Henriques,
	Greg KH, Anna Schumaker, Jeff Layton, Steve French,
	Miklos Szeredi, Trond Myklebust, Alexander Viro, Darrick J. Wong,
	Dave Chinner, Nicolas Boichat, Ian Lance Taylor, Luis Lozano,
	Andreas Dilger, Olga Kornievskaia, Christoph Hellwig, ceph-devel,
	linux-kernel, CIFS, samba-technical, linux-fsdevel,
	Linux NFS Mailing List, Walter Harms

Hi Amir,

On 5/10/21 4:26 PM, Amir Goldstein wrote:
> On Mon, May 10, 2021 at 3:01 AM Michael Kerrisk (man-pages)
> <mtk.manpages@gmail.com> wrote:
>>
>> Hi Alex,
>>
>> On 5/10/21 9:39 AM, Alejandro Colomar wrote:
>>> Linux 5.12 fixes a regression.
> 
> Nope.
> That never happened:
> https://lore.kernel.org/linux-fsdevel/8735v4tcye.fsf@suse.de/
> 
>>>
>>> Cross-filesystem (introduced in 5.3) copies were buggy.
>>>
>>> Move the statements documenting cross-fs to BUGS.
>>> Kernels 5.3..5.11 should be patched soon.
>>>
>>> State version information for some errors related to this.
>>
>> Thanks. Patch applied.
> 
> I guess that would need to be reverted...

Thanks for catching that. I had not pushed the patch, so 
I'll just drop it.

Cheers,

Michael


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-05-10 16:35 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <20210509213930.94120-1-alx.manpages@gmail.com>
2021-05-09 21:39 ` [PATCH] copy_file_range.2: Update cross-filesystem support for 5.12 Alejandro Colomar
2021-05-10  0:01   ` Michael Kerrisk (man-pages)
2021-05-10  4:26     ` Amir Goldstein
2021-05-10 16:34       ` Michael Kerrisk (man-pages)

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).