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rCDQYyakH2tJNQgkXkeLodBKF4bHiBbuwj0E39S9wmGgg+q4OTnAO/yhQGknle7a7G5xHBwE i0HjnLoJP5jDcoMTabZTIazXmJz3pKM11HYJ5/ZsTIf3ZRJJKIvXJpbmcAPVwTZII6XxiJdh RSSX4Mvd5pL/+5WI6NTdW6DMfigTtdd85fe6PwBNVJL2ZvBfsBJZ5rxg1TOH3KLsYBqBTgW2 glQofxhkJhDEcvjLhe3Y2BlbCWKOmvM8XS9TRt0OwUs= Message-ID: Date: Wed, 28 Aug 2019 22:07:45 -0400 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: <20190807142114.17569-3-danielhb413@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.63]); Thu, 29 Aug 2019 02:07:46 +0000 (UTC) Content-Transfer-Encoding: quoted-printable 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 v5 2/4] block.c: adding bdrv_delete_file 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: kwolf@redhat.com, berrange@redhat.com, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 8/7/19 10:21 AM, Daniel Henrique Barboza wrote: > Using the new 'bdrv_co_delete_file' interface, bdrv_delete_file > can be used in a way similar of the existing bdrv_create_file to > to clean up a created file. >=20 > The logic is also similar to what is already done in bdrv_create_file: > a qemu_coroutine is created if needed, a specialized function > bdrv_delete_co_entry is used to call the bdrv_co_delete_file > co-routine of the driver, if the driver implements it. >=20 > Suggested-by: Daniel P. Berrang=C3=A9 > Signed-off-by: Daniel Henrique Barboza > --- > block.c | 77 +++++++++++++++++++++++++++++++++++++++++++ > include/block/block.h | 1 + > 2 files changed, 78 insertions(+) >=20 > diff --git a/block.c b/block.c > index cbd8da5f3b..1e20250627 100644 > --- a/block.c > +++ b/block.c > @@ -547,6 +547,83 @@ int bdrv_create_file(const char *filename, QemuOpt= s *opts, Error **errp) > return ret; > } > =20 > +typedef struct DeleteCo { > + BlockDriver *drv; > + BlockDriverState *bs; > + int ret; > + Error *err; > +} DeleteCo; > + > +static void coroutine_fn bdrv_delete_co_entry(void *opaque) > +{ > + Error *local_err =3D NULL; > + DeleteCo *dco =3D opaque; > + > + assert(dco->bs); > + > + dco->ret =3D dco->drv->bdrv_co_delete_file(dco->bs, &local_err); > + error_propagate(&dco->err, local_err); > +} > + > +int bdrv_delete_file(const char *filename, Error **errp) > +{ > + BlockDriver *drv =3D bdrv_find_protocol(filename, true, NULL); > + BlockDriverState *bs =3D bdrv_open(filename, NULL, NULL, > + BDRV_O_RDWR | BDRV_O_PROTOCOL, NU= LL); > + DeleteCo dco =3D { > + .drv =3D drv, > + .bs =3D bs, > + .ret =3D NOT_DONE, > + .err =3D NULL, > + }; > + Coroutine *co; > + int ret; > + > + if (!drv) { > + error_setg(errp, "File '%s' has unknown format", filename); > + ret =3D -ENOENT; > + goto out; > + } > + I was going to say that ENOENT is a weird error here, but I see it used for !drv a few other places in block.c too, alongside EINVAL and ENOMEDIUM. ENOMEDIUM loks like the most popular. > + if (!drv->bdrv_co_delete_file) { > + error_setg(errp, "Driver '%s' does not support image delete", > + drv->format_name); > + ret =3D -ENOTSUP; > + goto out; > + } > + > + if (!bs) { > + error_setg(errp, "Could not open image '%s' for erasing", > + filename); > + ret =3D 1; Please keep all errors negative (or at least consistent within a function= ). I'm also wondering if we want a version of delete that doesn't try to open a file directly -- i.e. a version that exists like this: bdrv_co_delete_file(BlockDriverState *bs, Error **errp); That simply dispatches based on bs->drv to the correct routine. Then, you are free to have bdrv_delete_file handle the open (and let the opening figure out what driver it needs), and just hand off the bds to bdrv_co_delete_file. I'm not the authority for block.c, though, so maaaybe I'm giving you bad advice here. Kevin's away on PTO for a bit and gave you advice most recently, so I might try to gently ask him for more feedback next week. > + goto out; > + } > + > + if (qemu_in_coroutine()) { > + /* Fast-path if already in coroutine context */ > + bdrv_delete_co_entry(&dco); > + } else { > + co =3D qemu_coroutine_create(bdrv_delete_co_entry, &dco); > + qemu_coroutine_enter(co); > + while (dco.ret =3D=3D NOT_DONE) { > + aio_poll(qemu_get_aio_context(), true); > + } > + } > + > + ret =3D dco.ret; > + if (ret < 0) { > + if (dco.err) { > + error_propagate(errp, dco.err); > + } else { > + error_setg_errno(errp, -ret, "Could not delete image"); > + } > + } > + > +out: > + bdrv_unref(bs); > + return ret; > +} > + > /** > * Try to get @bs's logical and physical block size. > * On success, store them in @bsz struct and return 0. > diff --git a/include/block/block.h b/include/block/block.h > index 50a07c1c33..5e83532364 100644 > --- a/include/block/block.h > +++ b/include/block/block.h > @@ -369,6 +369,7 @@ bool bdrv_is_backing_chain_frozen(BlockDriverState = *bs, BlockDriverState *base, > int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *= base, > Error **errp); > void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverStat= e *base); > +int bdrv_delete_file(const char *filename, Error **errp); > =20 > =20 > typedef struct BdrvCheckResult { >=20