On 06/15/2017 04:53 PM, Darrick J. Wong wrote:
> On Thu, Jun 15, 2017 at 10:39:42AM -0400, Olga Kornievskaia wrote:
>> On Wed, Jun 14, 2017 at 11:59 PM, Darrick J. Wong
>> <darrick.wong@xxxxxxxxxx> wrote:
>>> On Wed, Jun 14, 2017 at 02:53:35PM -0400, Olga Kornievskaia wrote:
>>>> This is a proposal to allow 64bit count to copy and return as
>>>> a result of a copy_file_range. No attempt was made to share code
>>>> with the 32bit function because 32bit interface should probably
>>>> get depreciated.
>>>>
>>>> Why use 64bit? Current uses of 32bit are by clone_file_range()
>>>> which could use 64bit count and NFS copy_file_range also supports
>>>> 64bit count value.
>>>>
>>>> Also with this proposal off-the-bet allow the userland to copy
>>>> between different mount points.
>>>>
>>>> Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx>
>>>> ---
>>>> arch/x86/entry/syscalls/syscall_32.tbl | 1 +
>>>> arch/x86/entry/syscalls/syscall_64.tbl | 1 +
>>>> fs/read_write.c | 146 +++++++++++++++++++++++++++++++--
>>>> include/linux/fs.h | 4 +
>>>> include/linux/syscalls.h | 3 +
>>>> include/uapi/asm-generic/unistd.h | 4 +-
>>>> kernel/sys_ni.c | 1 +
>>>> 7 files changed, 154 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
>>>> index 448ac21..1f5f1e7 100644
>>>> --- a/arch/x86/entry/syscalls/syscall_32.tbl
>>>> +++ b/arch/x86/entry/syscalls/syscall_32.tbl
>>>> @@ -391,3 +391,4 @@
>>>> 382 i386 pkey_free sys_pkey_free
>>>> 383 i386 statx sys_statx
>>>> 384 i386 arch_prctl sys_arch_prctl compat_sys_arch_prctl
>>>> +385 i386 copy_file_range64 sys_copy_file_range64
>>>> diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
>>>> index 5aef183..e658bbe 100644
>>>> --- a/arch/x86/entry/syscalls/syscall_64.tbl
>>>> +++ b/arch/x86/entry/syscalls/syscall_64.tbl
>>>> @@ -339,6 +339,7 @@
>>>> 330 common pkey_alloc sys_pkey_alloc
>>>> 331 common pkey_free sys_pkey_free
>>>> 332 common statx sys_statx
>>>> +333 64 copy_file_range64 sys_copy_file_range64
>>>>
>>>> #
>>>> # x32-specific system call numbers start at 512 to avoid cache impact
>>>> diff --git a/fs/read_write.c b/fs/read_write.c
>>>> index e3ee985..c9c072b 100644
>>>> --- a/fs/read_write.c
>>>> +++ b/fs/read_write.c
>>>> @@ -1700,7 +1700,7 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
>>>> return ret;
>>>> }
>>>>
>>>> -static int clone_verify_area(struct file *file, loff_t pos, u64 len, bool write)
>>>> +static int rw64_verify_area(struct file *file, loff_t pos, u64 len, bool write)
>>>> {
>>>> struct inode *inode = file_inode(file);
>>>>
>>>> @@ -1723,6 +1723,142 @@ static int clone_verify_area(struct file *file, loff_t pos, u64 len, bool write)
>>>> return security_file_permission(file, write ? MAY_WRITE : MAY_READ);
>>>> }
>>>>
>>>> +u64 vfs_copy_file_range64(struct file *file_in, loff_t pos_in,
>>>> + struct file *file_out, loff_t pos_out,
>>>> + u64 len, unsigned int flags)
>>>
>>> AFAICT the difference between vfs_copy_file_range() and
>>> vfs_copy_file_range64() is that you've replaced 'size_t len' with
>>> 'u64 len', correct?
>>
>> That and I'm asking to allow for cross-device copy to be allowed by
>> the system call.
>
> I was fine letting each fs decide if it was going to allow cross-device
> copy or not, but Christoph argued that since we don't generally allow
> operations across mountpoints we shouldn't allow cross-mountpoint
> {clone,copy}_file_range either.
>
> Roughly translated, XFS has no cross-device copy abilities, there aren't
> any plans to add it, so I don't feel motivated to argue for it... but if
> the nfs community is so motivated (it sounds like it) then y'all could
> try one more time.
>
So since XFS (or any other local fs) does not have this ability,
NFS does not needed it?? That can't be the reason for the
push back that is denying NFS this ability..
steved.
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