The following functions fail if bs->drv does not implement them:
bdrv_probe_blocksizes
bdrv_probe_geometry
bdrv_truncate
bdrv_has_zero_init
bdrv_get_info
bdrv_media_changed
bdrv_eject
bdrv_lock_medium
bdrv_co_ioctl
Instead, the call should be passed to bs->file if it exists, to allow
filter drivers to support those methods without implementing them.
Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr>
---
block.c | 45 ++++++++++++++++++++++++++++++++++-----------
block/io.c | 4 ++++
2 files changed, 38 insertions(+), 11 deletions(-)
diff --git a/block.c b/block.c
index 69439628..ad11230a 100644
--- a/block.c
+++ b/block.c
@@ -494,6 +494,8 @@ int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
if (drv && drv->bdrv_probe_blocksizes) {
return drv->bdrv_probe_blocksizes(bs, bsz);
+ } else if (bs->file && bs->file->bs) {
+ return bdrv_probe_blocksizes(bs->file->bs, bsz);
}
return -ENOTSUP;
@@ -511,6 +513,8 @@ int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
if (drv && drv->bdrv_probe_geometry) {
return drv->bdrv_probe_geometry(bs, geo);
+ } else if (bs->file && bs->file->bs) {
+ return bdrv_probe_geometry(bs->file->bs, geo);
}
return -ENOTSUP;
@@ -3406,13 +3410,18 @@ int bdrv_truncate(BdrvChild *child, int64_t offset, Error **errp)
assert(child->perm & BLK_PERM_RESIZE);
- if (!drv) {
- error_setg(errp, "No medium inserted");
- return -ENOMEDIUM;
- }
- if (!drv->bdrv_truncate) {
- error_setg(errp, "Image format driver does not support resize");
- return -ENOTSUP;
+ if (!drv || !drv->bdrv_truncate) {
+ if (bs->file && bs->file->bs) {
+ return bdrv_truncate(bs->file, offset, errp);
+ }
+ if (!drv) {
+ error_setg(errp, "No medium inserted");
+ return -ENOMEDIUM;
+ }
+ if (!drv->bdrv_truncate) {
+ error_setg(errp, "Image format driver does not support resize");
+ return -ENOTSUP;
+ }
}
if (bs->read_only) {
error_setg(errp, "Image is read-only");
@@ -3778,6 +3787,9 @@ int bdrv_has_zero_init(BlockDriverState *bs)
if (bs->drv->bdrv_has_zero_init) {
return bs->drv->bdrv_has_zero_init(bs);
}
+ if (bs->file && bs->file->bs) {
+ return bdrv_has_zero_init(bs->file->bs);
+ }
/* safe default */
return 0;
@@ -3832,10 +3844,15 @@ void bdrv_get_backing_filename(BlockDriverState *bs,
int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
BlockDriver *drv = bs->drv;
- if (!drv)
- return -ENOMEDIUM;
- if (!drv->bdrv_get_info)
- return -ENOTSUP;
+ if (!drv || !drv->bdrv_get_info) {
+ if (bs->file && bs->file->bs) {
+ return bdrv_get_info(bs->file->bs, bdi);
+ }
+ if (!drv)
+ return -ENOMEDIUM;
+ if (!drv->bdrv_get_info)
+ return -ENOTSUP;
+ }
memset(bdi, 0, sizeof(*bdi));
return drv->bdrv_get_info(bs, bdi);
}
@@ -4205,6 +4222,8 @@ int bdrv_media_changed(BlockDriverState *bs)
if (drv && drv->bdrv_media_changed) {
return drv->bdrv_media_changed(bs);
+ } else if (bs->file && bs->file->bs) {
+ bdrv_media_changed(bs->file->bs);
}
return -ENOTSUP;
}
@@ -4218,6 +4237,8 @@ void bdrv_eject(BlockDriverState *bs, bool eject_flag)
if (drv && drv->bdrv_eject) {
drv->bdrv_eject(bs, eject_flag);
+ } else if (bs->file && bs->file->bs) {
+ bdrv_eject(bs->file->bs, eject_flag);
}
}
@@ -4233,6 +4254,8 @@ void bdrv_lock_medium(BlockDriverState *bs, bool locked)
if (drv && drv->bdrv_lock_medium) {
drv->bdrv_lock_medium(bs, locked);
+ } else if (bs->file && bs->file->bs) {
+ bdrv_lock_medium(bs->file->bs, locked);
}
}
diff --git a/block/io.c b/block/io.c
index c72d7015..c1b73226 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2403,6 +2403,10 @@ int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf)
bdrv_inc_in_flight(bs);
if (!drv || (!drv->bdrv_aio_ioctl && !drv->bdrv_co_ioctl)) {
+ if (bs->file && bs->file->bs) {
+ bdrv_dec_in_flight(bs);
+ return bdrv_co_ioctl(bs->file->bs, req, buf);
+ }
co.ret = -ENOTSUP;
goto out;
}
--
2.11.0
On Wed, Jun 28, 2017 at 01:46:15AM +0300, Manos Pitsidianakis wrote:
> @@ -3406,13 +3410,18 @@ int bdrv_truncate(BdrvChild *child, int64_t offset, Error **errp)
>
> assert(child->perm & BLK_PERM_RESIZE);
>
> - if (!drv) {
> - error_setg(errp, "No medium inserted");
> - return -ENOMEDIUM;
> - }
> - if (!drv->bdrv_truncate) {
> - error_setg(errp, "Image format driver does not support resize");
> - return -ENOTSUP;
> + if (!drv || !drv->bdrv_truncate) {
bs->drv == NULL means the BDS is closed. We should not forward to
bs->file. In practice bs->file will be NULL but please leave the
original if statement unchanged so it's clear that !drv results in
-ENOMEDIUM.
The same applies to the other changes below.
> @@ -3832,10 +3844,15 @@ void bdrv_get_backing_filename(BlockDriverState *bs,
> int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
> {
> BlockDriver *drv = bs->drv;
> - if (!drv)
> - return -ENOMEDIUM;
> - if (!drv->bdrv_get_info)
> - return -ENOTSUP;
> + if (!drv || !drv->bdrv_get_info) {
> + if (bs->file && bs->file->bs) {
> + return bdrv_get_info(bs->file->bs, bdi);
> + }
> + if (!drv)
> + return -ENOMEDIUM;
QEMU coding style always uses curly braces, even when the if statement
body is just 1 line.
> diff --git a/block/io.c b/block/io.c
> index c72d7015..c1b73226 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -2403,6 +2403,10 @@ int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf)
>
> bdrv_inc_in_flight(bs);
> if (!drv || (!drv->bdrv_aio_ioctl && !drv->bdrv_co_ioctl)) {
> + if (bs->file && bs->file->bs) {
> + bdrv_dec_in_flight(bs);
> + return bdrv_co_ioctl(bs->file->bs, req, buf);
bdrv_dec_in_flight() must happen after the request finishes, otherwise
bdrv_drain() will break.
On Wed, Jun 28, 2017 at 01:46:15AM +0300, Manos Pitsidianakis wrote: > The following functions fail if bs->drv does not implement them: > > bdrv_probe_blocksizes > bdrv_probe_geometry > bdrv_truncate > bdrv_has_zero_init > bdrv_get_info > bdrv_media_changed > bdrv_eject > bdrv_lock_medium > bdrv_co_ioctl > > Instead, the call should be passed to bs->file if it exists, to allow > filter drivers to support those methods without implementing them. > > Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr> > --- > block.c | 45 ++++++++++++++++++++++++++++++++++----------- > block/io.c | 4 ++++ > 2 files changed, 38 insertions(+), 11 deletions(-) Will you send a block/raw-format.c patch that removes the forwarding functions that are no longer needed?
On 06/29/2017 09:05 AM, Stefan Hajnoczi wrote: > On Wed, Jun 28, 2017 at 01:46:15AM +0300, Manos Pitsidianakis wrote: >> The following functions fail if bs->drv does not implement them: >> >> bdrv_probe_blocksizes >> bdrv_probe_geometry >> bdrv_truncate >> bdrv_has_zero_init >> bdrv_get_info >> bdrv_media_changed >> bdrv_eject >> bdrv_lock_medium >> bdrv_co_ioctl >> >> Instead, the call should be passed to bs->file if it exists, to allow >> filter drivers to support those methods without implementing them. >> >> Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr> >> --- >> block.c | 45 ++++++++++++++++++++++++++++++++++----------- >> block/io.c | 4 ++++ >> 2 files changed, 38 insertions(+), 11 deletions(-) > > Will you send a block/raw-format.c patch that removes the forwarding > functions that are no longer needed? block/raw-format.c does some additional things thanks to its 'offset' parameter, so I think it will have to still implement things directly rather than relying on defaults. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
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