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[Bug tapsets/19882] New: copy_file_range missing from syscall tapset


https://sourceware.org/bugzilla/show_bug.cgi?id=19882

            Bug ID: 19882
           Summary: copy_file_range missing from syscall tapset
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: tapsets
          Assignee: systemtap at sourceware dot org
          Reporter: dsmith at redhat dot com
  Target Milestone: ---

he copy_file_range syscall was added in kernel 4.5 by the following kernel
commit:

====
commit 29732938a6289a15e907da234d6692a2ead71855                                 
Author: Zach Brown <zab@redhat.com>                                             
Date:   Tue Nov 10 16:53:30 2015 -0500                                          

    vfs: add copy_file_range syscall and vfs helper                             

    Add a copy_file_range() system call for offloading copies between           
    regular files.                                                              

    This gives an interface to underlying layers of the storage stack which     
    can copy without reading and writing all the data.  There are a few         
    candidates that should support copy offloading in the nearer term:          

    - btrfs shares extent references with its clone ioctl                       
    - NFS has patches to add a COPY command which copies on the server          
    - SCSI has a family of XCOPY commands which copy in the device              

    This system call avoids the complexity of also accelerating the creation    
    of the destination file by operating on an existing destination file        
    descriptor, not a path.                                                     

    Currently the high level vfs entry point limits copy offloading to files    
    on the same mount and super (and not in the same file).  This can be        
    relaxed if we get implementations which can copy between file systems       
    safely.                                                                     
====

Support for copy_file_range() should be added to the syscall tapset.

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