Date: Mon, 30 Sep 2019 15:08:46 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-releng@freebsd.org Subject: svn commit: r352905 - releng/12.1/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <201909301508.x8UF8kge087339@repo.freebsd.org>
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Author: avg Date: Mon Sep 30 15:08:45 2019 New Revision: 352905 URL: https://svnweb.freebsd.org/changeset/base/352905 Log: Merge from stable/12 r352723: fix dsl_scan_ds_clone_swapped logic PR: 239566 Approved by: re (gjb) Modified: releng/12.1/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c Directory Properties: releng/12.1/ (props changed) Modified: releng/12.1/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c ============================================================================== --- releng/12.1/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c Mon Sep 30 15:01:09 2019 (r352904) +++ releng/12.1/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_scan.c Mon Sep 30 15:08:45 2019 (r352905) @@ -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,
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