From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47659) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yl0J9-0004Fe-Ms for qemu-devel@nongnu.org; Wed, 22 Apr 2015 15:27:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yl0J8-0004Yc-DE for qemu-devel@nongnu.org; Wed, 22 Apr 2015 15:27:39 -0400 Message-ID: <5537F623.8090600@redhat.com> Date: Wed, 22 Apr 2015 13:27:31 -0600 From: Eric Blake MIME-Version: 1.0 References: <20461b471d6f38f4488957563b7999751e73b8e7.1429196435.git.berto@igalia.com> In-Reply-To: <20461b471d6f38f4488957563b7999751e73b8e7.1429196435.git.berto@igalia.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="na2O4PR8GQ44kEo9jAIAuEJbwEtbwVhw9" Subject: Re: [Qemu-devel] [PATCH 6/8] docs: Document how to stream to an intermediate layer List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alberto Garcia , qemu-devel@nongnu.org Cc: Kevin Wolf , qemu-block@nongnu.org, Stefan Hajnoczi , Max Reitz This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --na2O4PR8GQ44kEo9jAIAuEJbwEtbwVhw9 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 04/16/2015 09:12 AM, Alberto Garcia wrote: > Signed-off-by: Alberto Garcia > --- > docs/live-block-ops.txt | 30 +++++++++++++++++++----------- > 1 file changed, 19 insertions(+), 11 deletions(-) >=20 > diff --git a/docs/live-block-ops.txt b/docs/live-block-ops.txt > index a257087..3bf86be 100644 > --- a/docs/live-block-ops.txt > +++ b/docs/live-block-ops.txt > @@ -10,9 +10,9 @@ Snapshot live merge > Given a snapshot chain, described in this document in the following > format: > =20 > -[A] -> [B] -> [C] -> [D] > +[A] -> [B] -> [C] -> [D] -> [E] I think on the list we've mostly settled on a notation where we express this relation as: [A] <- [B] that is, the symbol "<-" makes more sense as "serves as a backing file of" than "->", so that you end up reading the relationship as "[A] serves as a backing of [B]" (or read right-to-left as "[B] has a backing file of [A]"). Of course, the direction of the arrows is pre-existing, so it doesn't hold up this patch, but we probably ought to scrub our examples to consistently use <-. > =20 > -Where the rightmost object ([D] in the example) described is the curre= nt > +Where the rightmost object ([E] in the example) described is the curre= nt > image which the guest OS has write access to. To the left of it is its= base > image, and so on accordingly until the leftmost image, which has no > base. > @@ -21,11 +21,13 @@ The snapshot live merge operation transforms such a= chain into a > smaller one with fewer elements, such as this transformation relative > to the first example: > =20 > -[A] -> [D] > +[A] -> [E] > =20 > -Currently only forward merge with target being the active image is > -supported, that is, data copy is performed in the right direction with= > -destination being the rightmost image. > +Data is copied in the right direction with destination being the > +rightmost image, but any other intermediate image can be specified > +instead, for instance from [B] into [D]: > + > +[A] -> [B] -> [D] -> [E] Should you really describe that as moving data from [B] into [D], or would it be better to describe it as moving the data from [C] into [D] such that [D] can now be backed by [B] instead of [C]? I don't know if it is worth a tweak, and modulo my question on this one sentence, I think you've done a good job documenting the feature addition, so: Reviewed-by: Eric Blake --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --na2O4PR8GQ44kEo9jAIAuEJbwEtbwVhw9 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJVN/YjAAoJEKeha0olJ0NqYpEIAIiC+RTnadhsCavSLuXAeDm8 xpj471XG9khrb5uzirnc7ww3dyxpqpuEhEYABaVIQiIF7GRtjaSAXuX1eVvIYiid 5znXbn98JbLI6g4TBQfN50Af+n5P+FsSLwJqRM3se44lBGTRWYrJwQ0ULI71qV03 mN2y5jR6xx1wFjR86WQazH6hWt5/Vt4eZ7+u2bwygn1YTADYOyNcDudoaCn10mSm Or3ktAGpWkiQk618mE1wqnvk2bmDYTyJn+9V/NPXT3TCWWHdNha3WrqI6gh/x+1T x2UJgLDV7gaBYOonLjcKZKCQzRbQcFJvt+DQDdeCEC3WD5Kh6sD+712CXZWS0oM= =Y6bH -----END PGP SIGNATURE----- --na2O4PR8GQ44kEo9jAIAuEJbwEtbwVhw9--