Commit eebe8a84 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: Make sure to initialize equiv when creating new snapshots 

Previously, equiv was set in the snapshot deletion path, which is where
it's needed - equiv, for snapshot ID equivalence classes, would ideally
be a private data structure to the snapshot deletion path.

But if a new snapshot is created while snapshot deletion is running,
move_key_to_correct_snapshot() moves a key to snapshot id 0 - oops.

Fixes: https://github.com/koverstreet/bcachefs/issues/593


Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 82142a55

fs/bcachefs/snapshot.c

+6 −2
Original line number Diff line number Diff line
@@ -343,7 +343,7 @@ int bch2_snapshot_lookup(struct btree_trans *trans, u32 id, 
				       BTREE_ITER_WITH_UPDATES, snapshot, s);

}



int bch2_snapshot_live(struct btree_trans *trans, u32 id)

static int bch2_snapshot_live(struct btree_trans *trans, u32 id)

{

	struct bch_snapshot v;

	int ret;
@@ -370,7 +370,7 @@ int bch2_snapshot_live(struct btree_trans *trans, u32 id) 
 * it's part of such a linear chain: this correctly sets equivalence classes on

 * startup if we run leaf to root (i.e. in natural key order).

 */

int bch2_snapshot_set_equiv(struct btree_trans *trans, struct bkey_s_c k)

static int bch2_snapshot_set_equiv(struct btree_trans *trans, struct bkey_s_c k)

{

	struct bch_fs *c = trans->c;

	unsigned i, nr_live = 0, live_idx = 0;
@@ -1071,6 +1071,10 @@ static int create_snapids(struct btree_trans *trans, u32 parent, u32 tree, 
			goto err;



		new_snapids[i]	= iter.pos.offset;



		mutex_lock(&c->snapshot_table_lock);

		snapshot_t_mut(c, new_snapids[i])->equiv = new_snapids[i];

		mutex_unlock(&c->snapshot_table_lock);

	}

err:

	bch2_trans_iter_exit(trans, &iter);

fs/bcachefs/snapshot.h

+0 −2
Original line number Diff line number Diff line
@@ -235,8 +235,6 @@ int bch2_snapshot_lookup(struct btree_trans *trans, u32 id, 
			 struct bch_snapshot *s);

int bch2_snapshot_get_subvol(struct btree_trans *, u32,

			     struct bch_subvolume *);

int bch2_snapshot_live(struct btree_trans *trans, u32 id);

int bch2_snapshot_set_equiv(struct btree_trans *trans, struct bkey_s_c k);



/* only exported for tests: */

int bch2_snapshot_node_create(struct btree_trans *, u32,