Fix consistency of ztest_device_removal_active

ztest currently uses the boolean flag ztest_device_removal_active
to protect some tests that may not run successfully if they occur
at the same time as ztest_device_removal(). Unfortunately, in the
event that ztest is in the middle of a device removal when it
decides to issue a SIGKILL, the device removal will be
automatically restarted (without setting the flag) when the pool
is re-imported on the next run. This patch corrects this by
ensuring that any in-progress removals are completed before running
further tests after the re-import.

This patch also makes a few small changes to prevent race conditions
involving the creation and destruction of spa->spa_vdev_removal,
since this field is not protected by any locks. Some checks that
may run concurrently with setting / unsetting this field have been
updated to check spa->spa_removing_phys.sr_state instead. The most
significant change here is that spa_removal_get_stats() no longer
accounts for in-flight work done, since that could result in a NULL
pointer dereference.

Reviewed by: Matthew Ahrens <[email protected]>
Reviewed-by: Serapheim Dimitropoulos <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tom Caputi <[email protected]>
Closes #8105 

1 files changed, 1 insertions, 8 deletions

diff --git a/module/zfs/vdev_removal.c b/module/zfs/vdev_removal.c
index e8d036c61..49b9ed3a1 100644
--- a/module/zfs/vdev_removal.c
+++ b/module/zfs/vdev_removal.c
@@ -672,7 +672,7 @@ spa_finish_removal(spa_t *spa, dsl_scan_state_t state, dmu_tx_t *tx)
 		vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id);
 		vdev_indirect_config_t *vic = &vd->vdev_indirect_config;
 
-		if (srp->sr_prev_indirect_vdev != UINT64_MAX) {
+		if (srp->sr_prev_indirect_vdev != -1) {
 			vdev_t *pvd;
 			pvd = vdev_lookup_top(spa,
 			    srp->sr_prev_indirect_vdev);
@@ -2145,13 +2145,6 @@ spa_removal_get_stats(spa_t *spa, pool_removal_stat_t *prs)
 	prs->prs_to_copy = spa->spa_removing_phys.sr_to_copy;
 	prs->prs_copied = spa->spa_removing_phys.sr_copied;
 
-	if (spa->spa_vdev_removal != NULL) {
-		for (int i = 0; i < TXG_SIZE; i++) {
-			prs->prs_copied +=
-			    spa->spa_vdev_removal->svr_bytes_done[i];
-		}
-	}
-
 	prs->prs_mapping_memory = 0;
 	uint64_t indirect_vdev_id =
 	    spa->spa_removing_phys.sr_prev_indirect_vdev;