Author: avg
Date: Wed Sep 25 20:00:59 2019
New Revision: 352723
URL: https://svnweb.freebsd.org/changeset/base/352723
Log:
MFC r352506: fix dsl_scan_ds_clone_swapped logic
PR: 239566
Modified:
stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c
==============================================================================
--- stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c Wed Sep
25 19:56:23 2019 (r352722)
+++ stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c Wed Sep
25 20:00:59 2019 (r352723)
@@ -2014,16 +2014,17 @@ ds_clone_swapped_bookmark(dsl_dataset_t *ds1, dsl_data
}
/*
- * Called when a parent dataset and its clone are swapped. If we were
+ * Called when an origin dataset and its clone are swapped. If we were
* currently traversing the dataset, we need to switch to traversing the
- * newly promoted parent.
+ * newly promoted clone.
*/
void
dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
{
dsl_pool_t *dp = ds1->ds_dir->dd_pool;
dsl_scan_t *scn = dp->dp_scan;
- uint64_t mintxg;
+ uint64_t mintxg1, mintxg2;
+ boolean_t ds1_queued, ds2_queued;
if (!dsl_scan_is_running(scn))
return;
@@ -2031,44 +2032,81 @@ dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_data
ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys.scn_bookmark);
ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys_cached.scn_bookmark);
- if (scan_ds_queue_contains(scn, ds1->ds_object, &mintxg)) {
- scan_ds_queue_remove(scn, ds1->ds_object);
- scan_ds_queue_insert(scn, ds2->ds_object, mintxg);
+ /*
+ * Handle the in-memory scan queue.
+ */
+ ds1_queued = scan_ds_queue_contains(scn, ds1->ds_object, &mintxg1);
+ ds2_queued = scan_ds_queue_contains(scn, ds2->ds_object, &mintxg2);
+
+ /* Sanity checking. */
+ if (ds1_queued) {
+ ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
+ ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
}
- if (scan_ds_queue_contains(scn, ds2->ds_object, &mintxg)) {
+ if (ds2_queued) {
+ ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
+ ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
+ }
+
+ if (ds1_queued && ds2_queued) {
+ /*
+ * If both are queued, we don't need to do anything.
+ * The swapping code below would not handle this case correctly,
+ * since we can't insert ds2 if it is already there. That's
+ * because scan_ds_queue_insert() prohibits a duplicate insert
+ * and panics.
+ */
+ } else if (ds1_queued) {
+ scan_ds_queue_remove(scn, ds1->ds_object);
+ scan_ds_queue_insert(scn, ds2->ds_object, mintxg1);
+ } else if (ds2_queued) {
scan_ds_queue_remove(scn, ds2->ds_object);
- scan_ds_queue_insert(scn, ds1->ds_object, mintxg);
+ scan_ds_queue_insert(scn, ds1->ds_object, mintxg2);
}
- if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
- ds1->ds_object, &mintxg) == 0) {
- int err;
- ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
- ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
- VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
+ /*
+ * Handle the on-disk scan queue.
+ * The on-disk state is an out-of-date version of the in-memory state,
+ * so the in-memory and on-disk values for ds1_queued and ds2_queued may
+ * be different. Therefore we need to apply the swap logic to the
+ * on-disk state independently of the in-memory state.
+ */
+ ds1_queued = zap_lookup_int_key(dp->dp_meta_objset,
+ scn->scn_phys.scn_queue_obj, ds1->ds_object, &mintxg1) == 0;
+ ds2_queued = zap_lookup_int_key(dp->dp_meta_objset,
+ scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg2) == 0;
+
+ /* Sanity checking. */
+ if (ds1_queued) {
+ ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
+ ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
+ }
+ if (ds2_queued) {
+ ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
+ ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
+ }
+
+ if (ds1_queued && ds2_queued) {
+ /*
+ * If both are queued, we don't need to do anything.
+ * Alternatively, we could check for EEXIST from
+ * zap_add_int_key() and back out to the original state, but
+ * that would be more work than checking for this case upfront.
+ */
+ } else if (ds1_queued) {
+ VERIFY3S(0, ==, zap_remove_int(dp->dp_meta_objset,
scn->scn_phys.scn_queue_obj, ds1->ds_object, tx));
- err = zap_add_int_key(dp->dp_meta_objset,
- scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg, tx);
- VERIFY(err == 0 || err == EEXIST);
- if (err == EEXIST) {
- /* Both were there to begin with */
- VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
- scn->scn_phys.scn_queue_obj,
- ds1->ds_object, mintxg, tx));
- }
+ VERIFY3S(0, ==, zap_add_int_key(dp->dp_meta_objset,
+ scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg1, tx));
zfs_dbgmsg("clone_swap ds %llu; in queue; "
"replacing with %llu",
(u_longlong_t)ds1->ds_object,
(u_longlong_t)ds2->ds_object);
- }
- if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
- ds2->ds_object, &mintxg) == 0) {
- ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
- ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
- VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
+ } else if (ds2_queued) {
+ VERIFY3S(0, ==, zap_remove_int(dp->dp_meta_objset,
scn->scn_phys.scn_queue_obj, ds2->ds_object, tx));
- VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
- scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg, tx));
+ VERIFY3S(0, ==, zap_add_int_key(dp->dp_meta_objset,
+ scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg2, tx));
zfs_dbgmsg("clone_swap ds %llu; in queue; "
"replacing with %llu",
(u_longlong_t)ds2->ds_object,
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
