| Message ID | 20180802081824.1398-1-houtao1@huawei.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
| Series | dm-thin: stop no_space_timeout worker before switch to write-mode | expand |
On Thu, Aug 02 2018 at 4:18am -0400, Hou Tao <houtao1@huawei.com> wrote: > Now both check_for_space() and do_no_space_timeout() will read & write > error_if_no_space in pool->pf. If these functions run concurrently as > shown in the following case, the error_if_no_space feature requested > by user may get lost. > > precondition: > * error_if_no_space = 0 > * Out-of-Data-Space occurs > * no_space_timeout worker has been queued > > CPU 0: CPU 1: > // delete a thin device > process_delete_mesg() > // inovked by commit() > set_pool_mode(pool, PM_WRITE) > pool->pf.error_if_no_space = \ > pt->requested_pf.error_if_no_space > > // timeout > do_no_space_timeout > // the user configuration is lost > pool->pf.error_if_no_space = true > pool->pf.mode = new_mode > > Fix it by stopping no_space_timeout worker before switching to write mode. > > Signed-off-by: Hou Tao <houtao1@huawei.com> > --- > drivers/md/dm-thin.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c > index b900723bbd0f..c6da4afc16cf 100644 > --- a/drivers/md/dm-thin.c > +++ b/drivers/md/dm-thin.c > @@ -1401,6 +1401,7 @@ static void check_for_space(struct pool *pool) > return; > > if (nr_free) { > + cancel_delayed_work_sync(&pool->no_space_timeout); > set_pool_mode(pool, PM_WRITE); > requeue_bios(pool); > } > -- > 2.16.2.dirty > Thanks for the patch, I tweaked the header a bit and also moved the cancel_delayed_work_sync() to set_pool_mode(), please see: https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-4.19&id=eff8f4c73dd13f7d53015fc911d66f6671dd82b8 Please let me know if you have any issues with this, otherwise it is staged for 4.19 inclussion. Thanks, Mike -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index b900723bbd0f..c6da4afc16cf 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -1401,6 +1401,7 @@ static void check_for_space(struct pool *pool) return; if (nr_free) { + cancel_delayed_work_sync(&pool->no_space_timeout); set_pool_mode(pool, PM_WRITE); requeue_bios(pool); }
Now both check_for_space() and do_no_space_timeout() will read & write error_if_no_space in pool->pf. If these functions run concurrently as shown in the following case, the error_if_no_space feature requested by user may get lost. precondition: * error_if_no_space = 0 * Out-of-Data-Space occurs * no_space_timeout worker has been queued CPU 0: CPU 1: // delete a thin device process_delete_mesg() // inovked by commit() set_pool_mode(pool, PM_WRITE) pool->pf.error_if_no_space = \ pt->requested_pf.error_if_no_space // timeout do_no_space_timeout // the user configuration is lost pool->pf.error_if_no_space = true pool->pf.mode = new_mode Fix it by stopping no_space_timeout worker before switching to write mode. Signed-off-by: Hou Tao <houtao1@huawei.com> --- drivers/md/dm-thin.c | 1 + 1 file changed, 1 insertion(+)