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bcachefs: Refactor delete_dead_snapshots()

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Consolidate per-key work into delete_dead_snapshots_process_key(), so we
now walk all keys once, not twice.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2024-05-26 22:22:30 -04:00
parent 218e5e0c2a
commit 82af5ceb5d
1 changed files with 25 additions and 40 deletions
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65
fs/bcachefs/snapshot.c
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@ -1351,7 +1351,7 @@ int bch2_snapshot_node_create(struct btree_trans *trans, u32 parent,
* that key to snapshot leaf nodes, where we can mutate it
*/
static int snapshot_delete_key(struct btree_trans *trans,
static int delete_dead_snapshots_process_key(struct btree_trans *trans,
struct btree_iter *iter,
struct bkey_s_c k,
snapshot_id_list *deleted,
@ -1360,26 +1360,26 @@ static int snapshot_delete_key(struct btree_trans *trans,
{
struct bch_fs *c = trans->c;
u32 equiv = bch2_snapshot_equiv(c, k.k->p.snapshot);
if (!equiv) /* key for invalid snapshot node, but we chose not to delete */
return 0;
if (!bkey_eq(k.k->p, *last_pos))
equiv_seen->nr = 0;
*last_pos = k.k->p;
if (snapshot_list_has_id(deleted, k.k->p.snapshot) ||
snapshot_list_has_id(equiv_seen, equiv)) {
if (snapshot_list_has_id(deleted, k.k->p.snapshot))
return bch2_btree_delete_at(trans, iter,
BTREE_UPDATE_internal_snapshot_node);
} else {
return snapshot_list_add(c, equiv_seen, equiv);
}
}
static int move_key_to_correct_snapshot(struct btree_trans *trans,
struct btree_iter *iter,
struct bkey_s_c k)
{
struct bch_fs *c = trans->c;
u32 equiv = bch2_snapshot_equiv(c, k.k->p.snapshot);
if (!bpos_eq(*last_pos, k.k->p) &&
snapshot_list_has_id(equiv_seen, equiv))
return bch2_btree_delete_at(trans, iter,
BTREE_UPDATE_internal_snapshot_node);
*last_pos = k.k->p;
int ret = snapshot_list_add_nodup(c, equiv_seen, equiv);
if (ret)
return ret;
/*
* When we have a linear chain of snapshot nodes, we consider
@ -1389,21 +1389,20 @@ static int move_key_to_correct_snapshot(struct btree_trans *trans,
*
* If there are multiple keys in different snapshots at the same
* position, we're only going to keep the one in the newest
* snapshot - the rest have been overwritten and are redundant,
* and for the key we're going to keep we need to move it to the
* equivalance class ID if it's not there already.
* snapshot (we delete the others above) - the rest have been
* overwritten and are redundant, and for the key we're going to keep we
* need to move it to the equivalance class ID if it's not there
* already.
*/
if (equiv != k.k->p.snapshot) {
struct bkey_i *new = bch2_bkey_make_mut_noupdate(trans, k);
struct btree_iter new_iter;
int ret;
ret = PTR_ERR_OR_ZERO(new);
int ret = PTR_ERR_OR_ZERO(new);
if (ret)
return ret;
new->k.p.snapshot = equiv;
struct btree_iter new_iter;
bch2_trans_iter_init(trans, &new_iter, iter->btree_id, new->k.p,
BTREE_ITER_all_snapshots|
BTREE_ITER_cached|
@ -1538,7 +1537,6 @@ int bch2_delete_dead_snapshots(struct bch_fs *c)
struct btree_trans *trans;
snapshot_id_list deleted = { 0 };
snapshot_id_list deleted_interior = { 0 };
u32 id;
int ret = 0;
if (!test_and_clear_bit(BCH_FS_need_delete_dead_snapshots, &c->flags))
@ -1585,33 +1583,20 @@ int bch2_delete_dead_snapshots(struct bch_fs *c)
if (ret)
goto err;
for (id = 0; id < BTREE_ID_NR; id++) {
for (unsigned btree = 0; btree < BTREE_ID_NR; btree++) {
struct bpos last_pos = POS_MIN;
snapshot_id_list equiv_seen = { 0 };
struct disk_reservation res = { 0 };
if (!btree_type_has_snapshots(id))
continue;
/*
* deleted inodes btree is maintained by a trigger on the inodes
* btree - no work for us to do here, and it's not safe to scan
* it because we'll see out of date keys due to the btree write
* buffer:
*/
if (id == BTREE_ID_deleted_inodes)
if (!btree_type_has_snapshots(btree))
continue;
ret = for_each_btree_key_commit(trans, iter,
id, POS_MIN,
btree, POS_MIN,
BTREE_ITER_prefetch|BTREE_ITER_all_snapshots, k,
&res, NULL, BCH_TRANS_COMMIT_no_enospc,
snapshot_delete_key(trans, &iter, k, &deleted, &equiv_seen, &last_pos)) ?:
for_each_btree_key_commit(trans, iter,
id, POS_MIN,
BTREE_ITER_prefetch|BTREE_ITER_all_snapshots, k,
&res, NULL, BCH_TRANS_COMMIT_no_enospc,
move_key_to_correct_snapshot(trans, &iter, k));
delete_dead_snapshots_process_key(trans, &iter, k, &deleted,
&equiv_seen, &last_pos));
bch2_disk_reservation_put(c, &res);
darray_exit(&equiv_seen);