On 09/25/2014 05:14 PM, Tony Breeds wrote: > try_fiemap() uses FIEMAP_FLAG_SYNC which has a significant performance > impact. > > Prefer seek_hole() over fiemap() to avoid this impact where possible. > seek_hole is more widely used and, arguably, has potential to be > optimised in the kernel.
It also has the potential to be less precise than fiemap on older kernels (any filesystem that supports fiemap but has not yet wired up seek_hole will get the kernel's default fallback of claiming no holes at all), but that problem will fade as more people use modern kernels. This matches what coreutils does, so I like it on that grounds. > > Reported-By: Michael Steffens <michael_steff...@posteo.de> > Signed-off-by: Tony Breeds <t...@bakeyournoodle.com> > Cc: Kevin Wolf <kw...@redhat.com> > Cc: Markus Armbruster <arm...@redhat.com> > Cc: Stefan Hajnoczi <stefa...@redhat.com> > Cc: Max Reitz <mre...@redhat.com> > Cc: Pádraig Brady <pbr...@redhat.com> > Cc: Eric Blake <ebl...@redhat.com> > --- > Changes since v1: > - split in to 2 patches > - tried to make the commit messages better Thanks; it is indeed better. > > block/raw-posix.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) Reviewed-by: Eric Blake <ebl...@redhat.com> -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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