From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:43275) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Te5xi-00039g-G7 for qemu-devel@nongnu.org; Thu, 29 Nov 2012 10:23:39 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Te5xc-0005pG-DH for qemu-devel@nongnu.org; Thu, 29 Nov 2012 10:23:38 -0500 Received: from mx3-phx2.redhat.com ([209.132.183.24]:41468) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Te5xc-0005p8-5S for qemu-devel@nongnu.org; Thu, 29 Nov 2012 10:23:32 -0500 Date: Thu, 29 Nov 2012 10:23:29 -0500 (EST) From: Paolo Bonzini Message-ID: <249699163.16251603.1354202609373.JavaMail.root@redhat.com> In-Reply-To: <1354199315-21683-1-git-send-email-s.priebe@profihost.ag> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCHv4] rbd block driver fix race between aio completition and aio cancel List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Priebe Cc: stefanha@gmail.com, ceph-devel@vger.kernel.org, qemu-devel@nongnu.org, josh durgin ----- Messaggio originale ----- > Da: "Stefan Priebe" > A: qemu-devel@nongnu.org > Cc: stefanha@gmail.com, "josh durgin" , ceph-dev= el@vger.kernel.org, pbonzini@redhat.com, > "Stefan Priebe" > Inviato: Gioved=C3=AC, 29 novembre 2012 15:28:35 > Oggetto: [PATCHv4] rbd block driver fix race between aio completition and= aio cancel >=20 > This one fixes a race which qemu had also in iscsi block driver > between cancellation and io completition. >=20 > qemu_rbd_aio_cancel was not synchronously waiting for the end of > the command. >=20 > To archieve this it introduces a new status flag which uses > -EINPROGRESS. >=20 > Changes since PATCHv3: > - removed unnecessary if condition in rbd_start_aio as we > haven't start io yet > - moved acb->status =3D 0 to rbd_aio_bh_cb so qemu_aio_wait always > waits until BH was executed >=20 > Changes since PATCHv2: > - fixed missing braces > - added vfree for bounce >=20 > Signed-off-by: Stefan Priebe > --- > block/rbd.c | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) >=20 > diff --git a/block/rbd.c b/block/rbd.c > index f3becc7..28e94ab 100644 > --- a/block/rbd.c > +++ b/block/rbd.c > @@ -77,6 +77,7 @@ typedef struct RBDAIOCB { > int error; > struct BDRVRBDState *s; > int cancelled; > + int status; > } RBDAIOCB; > =20 > typedef struct RADOSCB { > @@ -376,12 +377,6 @@ static void qemu_rbd_complete_aio(RADOSCB *rcb) > RBDAIOCB *acb =3D rcb->acb; > int64_t r; > =20 > - if (acb->cancelled) { > - qemu_vfree(acb->bounce); > - qemu_aio_release(acb); > - goto done; > - } > - > r =3D rcb->ret; > =20 > if (acb->cmd =3D=3D RBD_AIO_WRITE || > @@ -409,7 +404,6 @@ static void qemu_rbd_complete_aio(RADOSCB *rcb) > /* Note that acb->bh can be NULL in case where the aio was > cancelled */ > acb->bh =3D qemu_bh_new(rbd_aio_bh_cb, acb); > qemu_bh_schedule(acb->bh); > -done: > g_free(rcb); > } > =20 > @@ -568,6 +562,12 @@ static void qemu_rbd_aio_cancel(BlockDriverAIOCB > *blockacb) > { > RBDAIOCB *acb =3D (RBDAIOCB *) blockacb; > acb->cancelled =3D 1; > + > + while (acb->status =3D=3D -EINPROGRESS) { > + qemu_aio_wait(); > + } > + > + qemu_vfree(acb->bounce); This vfree is not needed, since the BH will run and do the free. Otherwise looks ok. > } > =20 > static const AIOCBInfo rbd_aiocb_info =3D { > @@ -639,6 +639,7 @@ static void rbd_aio_bh_cb(void *opaque) > acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : > acb->ret)); > qemu_bh_delete(acb->bh); > acb->bh =3D NULL; > + acb->status =3D 0; > =20 > qemu_aio_release(acb); > } > @@ -685,6 +686,7 @@ static BlockDriverAIOCB > *rbd_start_aio(BlockDriverState *bs, > acb->s =3D s; > acb->cancelled =3D 0; > acb->bh =3D NULL; > + acb->status =3D -EINPROGRESS; > =20 > if (cmd =3D=3D RBD_AIO_WRITE) { > qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size); > -- > 1.7.10.4 >=20 >=20