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Message-ID: <20250502200002.1309862-9-kent.overstreet@linux.dev>
Date: Fri, 2 May 2025 16:00:00 -0400
From: Kent Overstreet <kent.overstreet@...ux.dev>
To: linux-bcachefs@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Kent Overstreet <kent.overstreet@...ux.dev>
Subject: [PATCH 8/8] bcachefs: delete_dead_snapshot_keys_v2()
Since extents, dirents and xattrs require an inode with the
corresponding snapshot ID to exists, we can avoid a lot of scanning by
only scanning those trees for keys to process if the correspending inode
exists.
Signed-off-by: Kent Overstreet <kent.overstreet@...ux.dev>
---
fs/bcachefs/snapshot.c | 160 ++++++++++++++++++++++++++++++++++-------
1 file changed, 133 insertions(+), 27 deletions(-)
diff --git a/fs/bcachefs/snapshot.c b/fs/bcachefs/snapshot.c
index f074b9de5024..83b95269d38d 100644
--- a/fs/bcachefs/snapshot.c
+++ b/fs/bcachefs/snapshot.c
@@ -1427,6 +1427,12 @@ static unsigned live_child(struct bch_fs *c, u32 id)
return ret;
}
+static bool snapshot_id_dying(struct snapshot_delete *d, unsigned id)
+{
+ return snapshot_list_has_id(&d->delete_leaves, id) ||
+ interior_delete_has_id(&d->delete_interior, id) != 0;
+}
+
static int delete_dead_snapshots_process_key(struct btree_trans *trans,
struct btree_iter *iter,
struct bkey_s_c k)
@@ -1486,6 +1492,126 @@ static bool skip_unrelated_snapshot_tree(struct btree_trans *trans, struct btree
return ret;
}
+static int delete_dead_snapshot_keys_v1(struct btree_trans *trans)
+{
+ struct bch_fs *c = trans->c;
+ struct snapshot_delete *d = &c->snapshot_delete;
+
+ for (d->pos.btree = 0; d->pos.btree < BTREE_ID_NR; d->pos.btree++) {
+ struct disk_reservation res = { 0 };
+
+ d->pos.pos = POS_MIN;
+
+ if (!btree_type_has_snapshots(d->pos.btree))
+ continue;
+
+ int ret = for_each_btree_key_commit(trans, iter,
+ d->pos.btree, POS_MIN,
+ BTREE_ITER_prefetch|BTREE_ITER_all_snapshots, k,
+ &res, NULL, BCH_TRANS_COMMIT_no_enospc, ({
+ d->pos.pos = iter.pos;
+
+ if (skip_unrelated_snapshot_tree(trans, &iter))
+ continue;
+
+ delete_dead_snapshots_process_key(trans, &iter, k);
+ }));
+
+ bch2_disk_reservation_put(c, &res);
+
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int delete_dead_snapshot_keys_range(struct btree_trans *trans, enum btree_id btree,
+ struct bpos start, struct bpos end)
+{
+ struct bch_fs *c = trans->c;
+ struct snapshot_delete *d = &c->snapshot_delete;
+ struct disk_reservation res = { 0 };
+
+ d->pos.btree = btree;
+ d->pos.pos = POS_MIN;
+
+ int ret = for_each_btree_key_max_commit(trans, iter,
+ btree, start, end,
+ BTREE_ITER_prefetch|BTREE_ITER_all_snapshots, k,
+ &res, NULL, BCH_TRANS_COMMIT_no_enospc, ({
+ d->pos.pos = iter.pos;
+ delete_dead_snapshots_process_key(trans, &iter, k);
+ }));
+
+ bch2_disk_reservation_put(c, &res);
+ return ret;
+}
+
+static int delete_dead_snapshot_keys_v2(struct btree_trans *trans)
+{
+ struct bch_fs *c = trans->c;
+ struct snapshot_delete *d = &c->snapshot_delete;
+ struct disk_reservation res = { 0 };
+ int ret = 0;
+
+ struct btree_iter iter;
+ bch2_trans_iter_init(trans, &iter, BTREE_ID_inodes, POS_MIN,
+ BTREE_ITER_prefetch|BTREE_ITER_all_snapshots);
+
+ while (1) {
+ struct bkey_s_c k;
+ ret = lockrestart_do(trans,
+ bkey_err(k = bch2_btree_iter_peek(trans, &iter)));
+ if (ret)
+ break;
+
+ if (!k.k)
+ break;
+
+ d->pos.btree = iter.btree_id;
+ d->pos.pos = iter.pos;
+
+ if (skip_unrelated_snapshot_tree(trans, &iter))
+ continue;
+
+ if (snapshot_id_dying(d, k.k->p.snapshot)) {
+ struct bpos start = POS(k.k->p.offset, 0);
+ struct bpos end = POS(k.k->p.offset, U64_MAX);
+
+ ret = delete_dead_snapshot_keys_range(trans, BTREE_ID_extents, start, end) ?:
+ delete_dead_snapshot_keys_range(trans, BTREE_ID_dirents, start, end) ?:
+ delete_dead_snapshot_keys_range(trans, BTREE_ID_xattrs, start, end);
+ if (ret)
+ break;
+
+ bch2_btree_iter_set_pos(trans, &iter, POS(0, k.k->p.offset + 1));
+ } else {
+ bch2_btree_iter_advance(trans, &iter);
+ }
+ }
+ bch2_trans_iter_exit(trans, &iter);
+
+ if (ret)
+ goto err;
+
+ ret = for_each_btree_key_commit(trans, iter,
+ BTREE_ID_inodes, POS_MIN,
+ BTREE_ITER_prefetch|BTREE_ITER_all_snapshots, k,
+ &res, NULL, BCH_TRANS_COMMIT_no_enospc, ({
+ d->pos.btree = iter.btree_id;
+ d->pos.pos = iter.pos;
+
+ if (skip_unrelated_snapshot_tree(trans, &iter))
+ continue;
+
+ delete_dead_snapshots_process_key(trans, &iter, k);
+ }));
+err:
+ bch2_disk_reservation_put(c, &res);
+ return ret;
+}
+
/*
* For a given snapshot, if it doesn't have a subvolume that points to it, and
* it doesn't have child snapshot nodes - it's now redundant and we can mark it
@@ -1666,33 +1792,13 @@ int bch2_delete_dead_snapshots(struct bch_fs *c)
goto err;
}
- for (d->pos.btree = 0; d->pos.btree < BTREE_ID_NR; d->pos.btree++) {
- struct disk_reservation res = { 0 };
-
- d->pos.pos = POS_MIN;
-
- if (!btree_type_has_snapshots(d->pos.btree))
- continue;
-
- ret = for_each_btree_key_commit(trans, iter,
- d->pos.btree, POS_MIN,
- BTREE_ITER_prefetch|BTREE_ITER_all_snapshots, k,
- &res, NULL, BCH_TRANS_COMMIT_no_enospc, ({
- d->pos.pos = iter.pos;
-
- if (skip_unrelated_snapshot_tree(trans, &iter))
- continue;
-
- delete_dead_snapshots_process_key(trans, &iter, k);
- }));
-
- bch2_disk_reservation_put(c, &res);
-
- if (!bch2_err_matches(ret, EROFS))
- bch_err_msg(c, ret, "deleting keys from dying snapshots");
- if (ret)
- goto err;
- }
+ ret = !bch2_request_incompat_feature(c, bcachefs_metadata_version_snapshot_deletion_v2)
+ ? delete_dead_snapshot_keys_v2(trans)
+ : delete_dead_snapshot_keys_v1(trans);
+ if (!bch2_err_matches(ret, EROFS))
+ bch_err_msg(c, ret, "deleting keys from dying snapshots");
+ if (ret)
+ goto err;
darray_for_each(d->delete_leaves, i) {
ret = commit_do(trans, NULL, NULL, 0,
--
2.49.0
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