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Tue, 6 Aug 2019 16:09:33 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-204-49.brq.redhat.com [10.40.204.49]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 15F6219C5B; Tue, 6 Aug 2019 16:09:28 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20190806152611.280389-1-vsementsov@virtuozzo.com> From: Max Reitz Openpgp: preference=signencrypt Autocrypt: addr=mreitz@redhat.com; prefer-encrypt=mutual; keydata= mQENBFXOJlcBCADEyyhOTsoa/2ujoTRAJj4MKA21dkxxELVj3cuILpLTmtachWj7QW+TVG8U /PsMCFbpwsQR7oEy8eHHZwuGQsNpEtNC2G/L8Yka0BIBzv7dEgrPzIu+W3anZXQW4702+uES U29G8TP/NGfXRRHGlbBIH9KNUnOSUD2vRtpOLXkWsV5CN6vQFYgQfFvmp5ZpPeUe6xNplu8V mcTw8OSEDW/ZnxJc8TekCKZSpdzYoxfzjm7xGmZqB18VFwgJZlIibt1HE0EB4w5GsD7x5ekh awIe3RwoZgZDLQMdOitJ1tUc8aqaxvgA4tz6J6st8D8pS//m1gAoYJWGwwIVj1DjTYLtABEB AAG0HU1heCBSZWl0eiA8bXJlaXR6QHJlZGhhdC5jb20+iQFTBBMBCAA9AhsDBQkSzAMABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheABQJVzie5FRhoa3A6Ly9rZXlzLmdudXBnLm5ldAAKCRD0 B9sAYdXPQDcIB/9uNkbYEex1rHKz3mr12uxYMwLOOFY9fstP5aoVJQ1nWQVB6m2cfKGdcRe1 2/nFaHSNAzT0NnKz2MjhZVmcrpyd2Gp2QyISCfb1FbT82GMtXFj1wiHmPb3CixYmWGQUUh+I AvUqsevLA+WihgBUyaJq/vuDVM1/K9Un+w+Tz5vpeMidlIsTYhcsMhn0L9wlCjoucljvbDy/ 8C9L2DUdgi3XTa0ORKeflUhdL4gucWoAMrKX2nmPjBMKLgU7WLBc8AtV+84b9OWFML6NEyo4 4cP7cM/07VlJK53pqNg5cHtnWwjHcbpGkQvx6RUx6F1My3y52vM24rNUA3+ligVEgPYBuQEN BFXOJlcBCADAmcVUNTWT6yLWQHvxZ0o47KCP8OcLqD+67T0RCe6d0LP8GsWtrJdeDIQk+T+F xO7DolQPS6iQ6Ak2/lJaPX8L0BkEAiMuLCKFU6Bn3lFOkrQeKp3u05wCSV1iKnhg0UPji9V2 W5eNfy8F4ZQHpeGUGy+liGXlxqkeRVhLyevUqfU0WgNqAJpfhHSGpBgihUupmyUg7lfUPeRM DzAN1pIqoFuxnN+BRHdAecpsLcbR8sQddXmDg9BpSKozO/JyBmaS1RlquI8HERQoe6EynJhd 64aICHDfj61rp+/0jTIcevxIIAzW70IadoS/y3DVIkuhncgDBvGbF3aBtjrJVP+5ABEBAAGJ ASUEGAEIAA8FAlXOJlcCGwwFCRLMAwAACgkQ9AfbAGHVz0CbFwf9F/PXxQR9i4N0iipISYjU sxVdjJOM2TMut+ZZcQ6NSMvhZ0ogQxJ+iEQ5OjnIputKvPVd5U7WRh+4lF1lB/NQGrGZQ1ic alkj6ocscQyFwfib+xIe9w8TG1CVGkII7+TbS5pXHRxZH1niaRpoi/hYtgzkuOPp35jJyqT/ /ELbqQTDAWcqtJhzxKLE/ugcOMK520dJDeb6x2xVES+S5LXby0D4juZlvUj+1fwZu+7Io5+B bkhSVPb/QdOVTpnz7zWNyNw+OONo1aBUKkhq2UIByYXgORPFnbfMY7QWHcjpBVw9MgC4tGeF R4bv+1nAMMxKmb5VvQCExr0eFhJUAHAhVg== Message-ID: Date: Tue, 6 Aug 2019 18:09:27 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190806152611.280389-1-vsementsov@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="r0efrs7WsagEdtYEFduGYp3z3BSTkUYsq" X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Tue, 06 Aug 2019 16:09:33 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v2] util/hbitmap: strict hbitmap_reset X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: fam@euphon.net, kwolf@redhat.com, jsnow@redhat.com, qemu-devel@nongnu.org, den@openvz.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --r0efrs7WsagEdtYEFduGYp3z3BSTkUYsq Content-Type: multipart/mixed; boundary="qJ5rIzEyMJr5ZtLUfFsBjFsyRBHdzLsEj"; protected-headers="v1" From: Max Reitz To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, jsnow@redhat.com, fam@euphon.net, kwolf@redhat.com, den@openvz.org Message-ID: Subject: Re: [PATCH v2] util/hbitmap: strict hbitmap_reset References: <20190806152611.280389-1-vsementsov@virtuozzo.com> In-Reply-To: <20190806152611.280389-1-vsementsov@virtuozzo.com> --qJ5rIzEyMJr5ZtLUfFsBjFsyRBHdzLsEj Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 06.08.19 17:26, Vladimir Sementsov-Ogievskiy wrote: > hbitmap_reset has an unobvious property: it rounds requested region up.= > It may provoke bugs, like in recently fixed write-blocking mode of > mirror: user calls reset on unaligned region, not keeping in mind that > there are possible unrelated dirty bytes, covered by rounded-up region > and information of this unrelated "dirtiness" will be lost. >=20 > Make hbitmap_reset strict: assert that arguments are aligned, allowing > only one exception when @start + @count =3D=3D hb->orig_size. It's need= ed > to comfort users of hbitmap_next_dirty_area, which cares about > hb->orig_size. >=20 > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- >=20 > v2 based on Max's https://github.com/XanClic/qemu.git block > which will be merged soon to 4.1, and this patch goes to 4.2 > Based-on: https://github.com/XanClic/qemu.git block >=20 > v1 was "[PATCH] util/hbitmap: fix unaligned reset", and as I understand= > we all agreed to just assert alignment instead of aligning down > automatically. >=20 > include/qemu/hbitmap.h | 5 +++++ > tests/test-hbitmap.c | 2 +- > util/hbitmap.c | 4 ++++ > 3 files changed, 10 insertions(+), 1 deletion(-) >=20 > diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h > index 4afbe6292e..7865e819ca 100644 > --- a/include/qemu/hbitmap.h > +++ b/include/qemu/hbitmap.h > @@ -132,6 +132,11 @@ void hbitmap_set(HBitmap *hb, uint64_t start, uint= 64_t count); > * @count: Number of bits to reset. > * > * Reset a consecutive range of bits in an HBitmap. > + * @start and @count must be aligned to bitmap granularity. The only e= xception > + * is resetting the tail of the bitmap: @count may be equal to @start = + > + * hb->orig_size, s/@start + hb->orig_size/hb->orig_size - @start/, I think. > in this case @count may be not aligned. @start + @count +are With those fixed: Reviewed-by: Max Reitz > + * allowed to be greater than hb->orig_size, but only if @start < hb->= orig_size > + * and @start + @count =3D ALIGN_UP(hb->orig_size, granularity). > */ > void hbitmap_reset(HBitmap *hb, uint64_t start, uint64_t count); > =20 > diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c > index 592d8219db..2be56d1597 100644 > --- a/tests/test-hbitmap.c > +++ b/tests/test-hbitmap.c > @@ -423,7 +423,7 @@ static void test_hbitmap_granularity(TestHBitmapDat= a *data, > hbitmap_test_check(data, 0); > hbitmap_test_set(data, 0, 3); > g_assert_cmpint(hbitmap_count(data->hb), =3D=3D, 4); > - hbitmap_test_reset(data, 0, 1); > + hbitmap_test_reset(data, 0, 2); > g_assert_cmpint(hbitmap_count(data->hb), =3D=3D, 2); > } > =20 > diff --git a/util/hbitmap.c b/util/hbitmap.c > index bcc0acdc6a..586920cb52 100644 > --- a/util/hbitmap.c > +++ b/util/hbitmap.c > @@ -476,6 +476,10 @@ void hbitmap_reset(HBitmap *hb, uint64_t start, ui= nt64_t count) > /* Compute range in the last layer. */ > uint64_t first; > uint64_t last =3D start + count - 1; > + uint64_t gran =3D 1ULL << hb->granularity; > + > + assert(!(start & (gran - 1))); > + assert(!(count & (gran - 1)) || (start + count =3D=3D hb->orig_siz= e)); > =20 > trace_hbitmap_reset(hb, start, count, > start >> hb->granularity, last >> hb->granular= ity); >=20 --qJ5rIzEyMJr5ZtLUfFsBjFsyRBHdzLsEj-- --r0efrs7WsagEdtYEFduGYp3z3BSTkUYsq Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl1JpjcACgkQ9AfbAGHV z0CUBAf/ScXgAitZ4siqtqa63CSDkhKMT1A32smL5mraMiFZg4EJjFXJri3FYRMy Vu4FxjSI5yjwza+/rduBVNoYZwgaA0qOXa1hgUg3Ll8laca47Cw8wqyWxOOHnVaQ CzsVI+nFHo+z2yeqefAfqeM5RULb3RrxnPByDvBPPjDgtM5zpVvTp3u8kxNnfCVq s2tZQgWK4TN1VMM2X6ch5j9GPyF4V7H3sWVyCqLLC64kdmhmh3PdRXJ2ylx2pps5 HPOsr0HV10FaEpFyN8RVsEbK1+lu6DLJKZ86TVs0I77lRvSSwakytIwsKNaOHmHT qBMDjGx/L2NjL9JpKWpP42/dAqsr2Q== =sHyY -----END PGP SIGNATURE----- --r0efrs7WsagEdtYEFduGYp3z3BSTkUYsq--