Messages in this thread | | | From | Trond Myklebust <> | Subject | Re: [PATCH v2] vfs: prevent copy_file_range to copy across devices | Date | Mon, 15 Feb 2021 16:02:20 +0000 |
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On Mon, 2021-02-15 at 15:43 +0000, Luis Henriques wrote: > Nicolas Boichat reported an issue when trying to use the > copy_file_range > syscall on a tracefs file. It failed silently because the file > content is > generated on-the-fly (reporting a size of zero) and copy_file_range > needs > to know in advance how much data is present.
That explanation makes no sense whatsoever. copy_file_range is a non- atomic operation and so the file can change while being copied. Any determination of 'how much data is present' that is made in advance would therefore be a flaw in the copy process being used (i.e. do_splice_direct()). Does sendfile() also 'issue' in the same way?
-- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@hammerspace.com
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