4.9-stable review patch. If anyone has any objections, please let me know.
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From: Hou Tao houtao1@huawei.com
commit 75294442d896f2767be34f75aca7cc2b0d01301f upstream.
Now both check_for_space() and do_no_space_timeout() will read & write pool->pf.error_if_no_space. If these functions run concurrently, as shown in the following case, the default setting of "queue_if_no_space" can get lost.
precondition: * error_if_no_space = false (aka "queue_if_no_space") * pool is in Out-of-Data-Space (OODS) mode * no_space_timeout worker has been queued
CPU 0: CPU 1: // delete a thin device process_delete_mesg() // check_for_space() invoked by commit() set_pool_mode(pool, PM_WRITE) pool->pf.error_if_no_space = \ pt->requested_pf.error_if_no_space
// timeout, pool is still in OODS mode do_no_space_timeout // "queue_if_no_space" config is lost pool->pf.error_if_no_space = true pool->pf.mode = new_mode
Fix it by stopping no_space_timeout worker when switching to write mode.
Fixes: bcc696fac11f ("dm thin: stay in out-of-data-space mode once no_space_timeout expires") Cc: stable@vger.kernel.org Signed-off-by: Hou Tao houtao1@huawei.com Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/md/dm-thin.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -2518,6 +2518,8 @@ static void set_pool_mode(struct pool *p case PM_WRITE: if (old_mode != new_mode) notify_of_pool_mode_change(pool, "write"); + if (old_mode == PM_OUT_OF_DATA_SPACE) + cancel_delayed_work_sync(&pool->no_space_timeout); pool->out_of_data_space = false; pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space; dm_pool_metadata_read_write(pool->pmd);