| Message ID | 20190130161948.15888-1-paul.durrant@citrix.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] xen-block: handle resize callback | expand |
On Wed, Jan 30, 2019 at 04:19:48PM +0000, Paul Durrant wrote: > Some frontend drivers will handle dynamic resizing of PV disks, so set up > the BlockDevOps resize_cb() method during xen_block_realize() to allow > this to be done. > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > --- > + /* > + * Mimic the behaviour of Linux xen-blkback and re-write the state > + * to trigger the frontend watch. > + */ > + xen_device_backend_set_state(xendev, backend_state); :(, that function doesn't write the state again if it hasn't changed. So in my testing, Linux never did anything.
> -----Original Message----- > From: Anthony PERARD [mailto:anthony.perard@citrix.com] > Sent: 31 January 2019 15:21 > To: Paul Durrant <Paul.Durrant@citrix.com> > Cc: qemu-devel@nongnu.org; qemu-block@nongnu.org; xen- > devel@lists.xenproject.org; Stefan Hajnoczi <stefanha@redhat.com>; Stefano > Stabellini <sstabellini@kernel.org>; Kevin Wolf <kwolf@redhat.com>; Max > Reitz <mreitz@redhat.com> > Subject: Re: [PATCH v2] xen-block: handle resize callback > > On Wed, Jan 30, 2019 at 04:19:48PM +0000, Paul Durrant wrote: > > Some frontend drivers will handle dynamic resizing of PV disks, so set > up > > the BlockDevOps resize_cb() method during xen_block_realize() to allow > > this to be done. > > > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > > --- > > > > + /* > > + * Mimic the behaviour of Linux xen-blkback and re-write the state > > + * to trigger the frontend watch. > > + */ > > + xen_device_backend_set_state(xendev, backend_state); > > :(, that function doesn't write the state again if it hasn't changed. > So in my testing, Linux never did anything. Gah! I forgot about that. Alright, it's going to have to be a bit more crude. Paul > > -- > Anthony PERARD
On Thu, Jan 31, 2019 at 03:22:18PM +0000, Paul Durrant wrote: > > -----Original Message----- > > From: Anthony PERARD [mailto:anthony.perard@citrix.com] > > Sent: 31 January 2019 15:21 > > To: Paul Durrant <Paul.Durrant@citrix.com> > > Cc: qemu-devel@nongnu.org; qemu-block@nongnu.org; xen- > > devel@lists.xenproject.org; Stefan Hajnoczi <stefanha@redhat.com>; Stefano > > Stabellini <sstabellini@kernel.org>; Kevin Wolf <kwolf@redhat.com>; Max > > Reitz <mreitz@redhat.com> > > Subject: Re: [PATCH v2] xen-block: handle resize callback > > > > On Wed, Jan 30, 2019 at 04:19:48PM +0000, Paul Durrant wrote: > > > Some frontend drivers will handle dynamic resizing of PV disks, so set > > up > > > the BlockDevOps resize_cb() method during xen_block_realize() to allow > > > this to be done. > > > > > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > > > --- > > > > > > > + /* > > > + * Mimic the behaviour of Linux xen-blkback and re-write the state > > > + * to trigger the frontend watch. > > > + */ > > > + xen_device_backend_set_state(xendev, backend_state); > > > > :(, that function doesn't write the state again if it hasn't changed. > > So in my testing, Linux never did anything. > > Gah! I forgot about that. Alright, it's going to have to be a bit more crude. more crude > Yes, I tried to ignore the check in _set_state and end-up with an infinit loop.
> -----Original Message----- > From: Anthony PERARD [mailto:anthony.perard@citrix.com] > Sent: 31 January 2019 15:25 > To: Paul Durrant <Paul.Durrant@citrix.com> > Cc: qemu-devel@nongnu.org; qemu-block@nongnu.org; xen- > devel@lists.xenproject.org; Stefan Hajnoczi <stefanha@redhat.com>; Stefano > Stabellini <sstabellini@kernel.org>; Kevin Wolf <kwolf@redhat.com>; Max > Reitz <mreitz@redhat.com> > Subject: Re: [PATCH v2] xen-block: handle resize callback > > On Thu, Jan 31, 2019 at 03:22:18PM +0000, Paul Durrant wrote: > > > -----Original Message----- > > > From: Anthony PERARD [mailto:anthony.perard@citrix.com] > > > Sent: 31 January 2019 15:21 > > > To: Paul Durrant <Paul.Durrant@citrix.com> > > > Cc: qemu-devel@nongnu.org; qemu-block@nongnu.org; xen- > > > devel@lists.xenproject.org; Stefan Hajnoczi <stefanha@redhat.com>; > Stefano > > > Stabellini <sstabellini@kernel.org>; Kevin Wolf <kwolf@redhat.com>; > Max > > > Reitz <mreitz@redhat.com> > > > Subject: Re: [PATCH v2] xen-block: handle resize callback > > > > > > On Wed, Jan 30, 2019 at 04:19:48PM +0000, Paul Durrant wrote: > > > > Some frontend drivers will handle dynamic resizing of PV disks, so > set > > > up > > > > the BlockDevOps resize_cb() method during xen_block_realize() to > allow > > > > this to be done. > > > > > > > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > > > > --- > > > > > > > > > > + /* > > > > + * Mimic the behaviour of Linux xen-blkback and re-write the > state > > > > + * to trigger the frontend watch. > > > > + */ > > > > + xen_device_backend_set_state(xendev, backend_state); > > > > > > :(, that function doesn't write the state again if it hasn't changed. > > > So in my testing, Linux never did anything. > > > > Gah! I forgot about that. Alright, it's going to have to be a bit more > crude. > > more crude > Yes, I tried to ignore the check in _set_state and end-up > with an infinit loop. Yes, you would. That check is there for a reason :-) I'll replace the call in xen-block.c with a call to xen_device_backend_printf(). Paul > > -- > Anthony PERARD
diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c index d0d8905a33..c6a15da024 100644 --- a/hw/block/dataplane/xen-block.c +++ b/hw/block/dataplane/xen-block.c @@ -50,7 +50,6 @@ struct XenBlockDataPlane { unsigned int nr_ring_ref; void *sring; int64_t file_blk; - int64_t file_size; int protocol; blkif_back_rings_t rings; int more_work; @@ -189,7 +188,7 @@ static int xen_block_parse_request(XenBlockRequest *request) request->req.seg[i].first_sect + 1) * dataplane->file_blk; request->size += len; } - if (request->start + request->size > dataplane->file_size) { + if (request->start + request->size > blk_getlength(dataplane->blk)) { error_report("error: access beyond end of file"); goto err; } @@ -638,7 +637,6 @@ XenBlockDataPlane *xen_block_dataplane_create(XenDevice *xendev, dataplane->xendev = xendev; dataplane->file_blk = conf->logical_block_size; dataplane->blk = conf->blk; - dataplane->file_size = blk_getlength(dataplane->blk); QLIST_INIT(&dataplane->inflight); QLIST_INIT(&dataplane->freelist); diff --git a/hw/block/trace-events b/hw/block/trace-events index d0851953c5..8020f9226a 100644 --- a/hw/block/trace-events +++ b/hw/block/trace-events @@ -126,6 +126,7 @@ xen_block_realize(const char *type, uint32_t disk, uint32_t partition) "%s d%up% xen_block_connect(const char *type, uint32_t disk, uint32_t partition) "%s d%up%u" xen_block_disconnect(const char *type, uint32_t disk, uint32_t partition) "%s d%up%u" xen_block_unrealize(const char *type, uint32_t disk, uint32_t partition) "%s d%up%u" +xen_block_size(const char *type, uint32_t disk, uint32_t partition, int64_t sectors) "%s d%up%u %"PRIi64 xen_disk_realize(void) "" xen_disk_unrealize(void) "" xen_cdrom_realize(void) "" diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c index a636487b3e..0f0799e861 100644 --- a/hw/block/xen-block.c +++ b/hw/block/xen-block.c @@ -144,6 +144,38 @@ static void xen_block_unrealize(XenDevice *xendev, Error **errp) } } +static void xen_block_set_size(XenBlockDevice *blockdev) +{ + const char *type = object_get_typename(OBJECT(blockdev)); + XenBlockVdev *vdev = &blockdev->props.vdev; + BlockConf *conf = &blockdev->props.conf; + int64_t sectors = blk_getlength(conf->blk) / conf->logical_block_size; + XenDevice *xendev = XEN_DEVICE(blockdev); + + trace_xen_block_size(type, vdev->disk, vdev->partition, sectors); + + xen_device_backend_printf(xendev, "sectors", "%"PRIi64, sectors); +} + +static void xen_block_resize_cb(void *opaque) +{ + XenBlockDevice *blockdev = opaque; + XenDevice *xendev = XEN_DEVICE(blockdev); + enum xenbus_state backend_state = xen_device_backend_get_state(xendev); + + xen_block_set_size(blockdev); + + /* + * Mimic the behaviour of Linux xen-blkback and re-write the state + * to trigger the frontend watch. + */ + xen_device_backend_set_state(xendev, backend_state); +} + +static const BlockDevOps xen_block_dev_ops = { + .resize_cb = xen_block_resize_cb, +}; + static void xen_block_realize(XenDevice *xendev, Error **errp) { XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev); @@ -180,7 +212,7 @@ static void xen_block_realize(XenDevice *xendev, Error **errp) } if (!blkconf_apply_backend_options(conf, blockdev->info & VDISK_READONLY, - false, errp)) { + true, errp)) { return; } @@ -197,6 +229,7 @@ static void xen_block_realize(XenDevice *xendev, Error **errp) return; } + blk_set_dev_ops(conf->blk, &xen_block_dev_ops, blockdev); blk_set_guest_block_size(conf->blk, conf->logical_block_size); if (conf->discard_granularity > 0) { @@ -215,9 +248,8 @@ static void xen_block_realize(XenDevice *xendev, Error **errp) xen_device_backend_printf(xendev, "sector-size", "%u", conf->logical_block_size); - xen_device_backend_printf(xendev, "sectors", "%"PRIi64, - blk_getlength(conf->blk) / - conf->logical_block_size); + + xen_block_set_size(blockdev); blockdev->dataplane = xen_block_dataplane_create(xendev, conf, blockdev->props.iothread);
Some frontend drivers will handle dynamic resizing of PV disks, so set up the BlockDevOps resize_cb() method during xen_block_realize() to allow this to be done. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> --- Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Anthony Perard <anthony.perard@citrix.com> Cc: Kevin Wolf <kwolf@redhat.com> Cc: Max Reitz <mreitz@redhat.com> v2: - re-write backend state after updating sectors --- hw/block/dataplane/xen-block.c | 4 +--- hw/block/trace-events | 1 + hw/block/xen-block.c | 40 ++++++++++++++++++++++++++++++---- 3 files changed, 38 insertions(+), 7 deletions(-)