• A
    ovl: use vfs_clone_file_range() for copy up if possible · 2ea98466
    Amir Goldstein 提交于
    When copying up within the same fs, try to use vfs_clone_file_range().
    This is very efficient when lower and upper are on the same fs
    with file reflink support. If vfs_clone_file_range() fails for any
    reason, copy up falls back to the regular data copy code.
    
    Tested correct behavior when lower and upper are on:
    1. same ext4 (copy)
    2. same xfs + reflink patches + mkfs.xfs (copy)
    3. same xfs + reflink patches + mkfs.xfs -m reflink=1 (reflink)
    4. different xfs + reflink patches + mkfs.xfs -m reflink=1 (copy)
    
    For comparison, on my laptop, xfstest overlay/001 (copy up of large
    sparse files) takes less than 1 second in the xfs reflink setup vs.
    25 seconds on the rest of the setups.
    Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
    Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
    2ea98466
copy_up.c 9.7 KB