| Message ID | 20220209105452.1694545-2-eesposit@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | block layer: permission API refactoring in preparation | expand |
Am 09.02.2022 um 11:54 hat Emanuele Giuseppe Esposito geschrieben: > Move the permission API calls into driver-specific callbacks > that always run under BQL. In this case, bdrv_crypto_luks > needs to perform permission checks before and after > qcrypto_block_amend_options(). The problem is that the caller, > block_crypto_amend_options_generic_luks(), can also run in I/O > from .bdrv_co_amend(). This does not comply with Global State-I/O API split, > as permissions API must always run under BQL. > > Firstly, introduce .bdrv_amend_pre_run() and .bdrv_amend_clean() > callbacks. These two callbacks are guaranteed to be invoked under > BQL, respectively before and after .bdrv_co_amend(). > They take care of performing the permission checks > in the same way as they are currently done before and after > qcrypto_block_amend_options(). > These callbacks are in preparation for next patch, where we > delete the original permission check. Right now they just add redundant > control. > > Then, call .bdrv_amend_pre_run() before job_start in > qmp_x_blockdev_amend(), so that it will be run before the job coroutine > is created and stay in the main loop. > As a cleanup, use JobDriver's .clean() callback to call > .bdrv_amend_clean(), and run amend-specific cleanup callbacks under BQL. > > Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> > --- > block/amend.c | 24 ++++++++++++++++++++++++ > block/crypto.c | 27 +++++++++++++++++++++++++++ > include/block/block_int.h | 14 ++++++++++++++ > 3 files changed, 65 insertions(+) > > diff --git a/block/amend.c b/block/amend.c > index 392df9ef83..329bca53dc 100644 > --- a/block/amend.c > +++ b/block/amend.c > @@ -53,10 +53,29 @@ static int coroutine_fn blockdev_amend_run(Job *job, Error **errp) > return ret; > } > > +static int blockdev_amend_pre_run(BlockdevAmendJob *s, Error **errp) > +{ > + if (s->bs->drv->bdrv_amend_pre_run) { > + return s->bs->drv->bdrv_amend_pre_run(s->bs, errp); > + } > + > + return 0; > +} > + > +static void blockdev_amend_clean(Job *job) > +{ > + BlockdevAmendJob *s = container_of(job, BlockdevAmendJob, common); > + > + if (s->bs->drv->bdrv_amend_clean) { > + s->bs->drv->bdrv_amend_clean(s->bs); > + } > +} > + > static const JobDriver blockdev_amend_job_driver = { > .instance_size = sizeof(BlockdevAmendJob), > .job_type = JOB_TYPE_AMEND, > .run = blockdev_amend_run, > + .clean = blockdev_amend_clean, > }; > > void qmp_x_blockdev_amend(const char *job_id, > @@ -113,5 +132,10 @@ void qmp_x_blockdev_amend(const char *job_id, > s->bs = bs, > s->opts = QAPI_CLONE(BlockdevAmendOptions, options), > s->force = has_force ? force : false; > + > + if (blockdev_amend_pre_run(s, errp)) { > + return; > + } > + > job_start(&s->common); > } > diff --git a/block/crypto.c b/block/crypto.c > index c8ba4681e2..59f768ea8d 100644 > --- a/block/crypto.c > +++ b/block/crypto.c > @@ -777,6 +777,31 @@ block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp) > return spec_info; > } > > +static int > +block_crypto_amend_prepare(BlockDriverState *bs, Error **errp) > +{ > + BlockCrypto *crypto = bs->opaque; > + > + /* apply for exclusive read/write permissions to the underlying file*/ Missing space before the end of the comment. > + crypto->updating_keys = true; > + return bdrv_child_refresh_perms(bs, bs->file, errp); > +} > + > +static void > +block_crypto_amend_cleanup(BlockDriverState *bs) > +{ > + BlockCrypto *crypto = bs->opaque; > + Error *errp = NULL; > + > + /* release exclusive read/write permissions to the underlying file*/ And here. I can fix this up while applying. Kevin
diff --git a/block/amend.c b/block/amend.c index 392df9ef83..329bca53dc 100644 --- a/block/amend.c +++ b/block/amend.c @@ -53,10 +53,29 @@ static int coroutine_fn blockdev_amend_run(Job *job, Error **errp) return ret; } +static int blockdev_amend_pre_run(BlockdevAmendJob *s, Error **errp) +{ + if (s->bs->drv->bdrv_amend_pre_run) { + return s->bs->drv->bdrv_amend_pre_run(s->bs, errp); + } + + return 0; +} + +static void blockdev_amend_clean(Job *job) +{ + BlockdevAmendJob *s = container_of(job, BlockdevAmendJob, common); + + if (s->bs->drv->bdrv_amend_clean) { + s->bs->drv->bdrv_amend_clean(s->bs); + } +} + static const JobDriver blockdev_amend_job_driver = { .instance_size = sizeof(BlockdevAmendJob), .job_type = JOB_TYPE_AMEND, .run = blockdev_amend_run, + .clean = blockdev_amend_clean, }; void qmp_x_blockdev_amend(const char *job_id, @@ -113,5 +132,10 @@ void qmp_x_blockdev_amend(const char *job_id, s->bs = bs, s->opts = QAPI_CLONE(BlockdevAmendOptions, options), s->force = has_force ? force : false; + + if (blockdev_amend_pre_run(s, errp)) { + return; + } + job_start(&s->common); } diff --git a/block/crypto.c b/block/crypto.c index c8ba4681e2..59f768ea8d 100644 --- a/block/crypto.c +++ b/block/crypto.c @@ -777,6 +777,31 @@ block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp) return spec_info; } +static int +block_crypto_amend_prepare(BlockDriverState *bs, Error **errp) +{ + BlockCrypto *crypto = bs->opaque; + + /* apply for exclusive read/write permissions to the underlying file*/ + crypto->updating_keys = true; + return bdrv_child_refresh_perms(bs, bs->file, errp); +} + +static void +block_crypto_amend_cleanup(BlockDriverState *bs) +{ + BlockCrypto *crypto = bs->opaque; + Error *errp = NULL; + + /* release exclusive read/write permissions to the underlying file*/ + crypto->updating_keys = false; + bdrv_child_refresh_perms(bs, bs->file, &errp); + + if (errp) { + error_report_err(errp); + } +} + static int block_crypto_amend_options_generic_luks(BlockDriverState *bs, QCryptoBlockAmendOptions *amend_options, @@ -931,6 +956,8 @@ static BlockDriver bdrv_crypto_luks = { .bdrv_get_specific_info = block_crypto_get_specific_info_luks, .bdrv_amend_options = block_crypto_amend_options_luks, .bdrv_co_amend = block_crypto_co_amend_luks, + .bdrv_amend_pre_run = block_crypto_amend_prepare, + .bdrv_amend_clean = block_crypto_amend_cleanup, .is_format = true, diff --git a/include/block/block_int.h b/include/block/block_int.h index 27008cfb22..31bd788919 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -124,6 +124,20 @@ struct BlockDriver { * on those children. */ bool is_format; + + /* + * This function is invoked under BQL before .bdrv_co_amend() + * (which in contrast does not necessarily run under the BQL) + * to allow driver-specific initialization code that requires + * the BQL, like setting up specific permission flags. + */ + int (*bdrv_amend_pre_run)(BlockDriverState *bs, Error **errp); + /* + * This function is invoked under BQL after .bdrv_co_amend() + * to allow cleaning up what was done in .bdrv_amend_pre_run(). + */ + void (*bdrv_amend_clean)(BlockDriverState *bs); + /* * Return true if @to_replace can be replaced by a BDS with the * same data as @bs without it affecting @bs's behavior (that is,
Move the permission API calls into driver-specific callbacks that always run under BQL. In this case, bdrv_crypto_luks needs to perform permission checks before and after qcrypto_block_amend_options(). The problem is that the caller, block_crypto_amend_options_generic_luks(), can also run in I/O from .bdrv_co_amend(). This does not comply with Global State-I/O API split, as permissions API must always run under BQL. Firstly, introduce .bdrv_amend_pre_run() and .bdrv_amend_clean() callbacks. These two callbacks are guaranteed to be invoked under BQL, respectively before and after .bdrv_co_amend(). They take care of performing the permission checks in the same way as they are currently done before and after qcrypto_block_amend_options(). These callbacks are in preparation for next patch, where we delete the original permission check. Right now they just add redundant control. Then, call .bdrv_amend_pre_run() before job_start in qmp_x_blockdev_amend(), so that it will be run before the job coroutine is created and stay in the main loop. As a cleanup, use JobDriver's .clean() callback to call .bdrv_amend_clean(), and run amend-specific cleanup callbacks under BQL. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> --- block/amend.c | 24 ++++++++++++++++++++++++ block/crypto.c | 27 +++++++++++++++++++++++++++ include/block/block_int.h | 14 ++++++++++++++ 3 files changed, 65 insertions(+)