From ca130b9c5e120994483a34c72526dcd4bf308d84 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Mon, 18 Oct 2021 14:46:57 -0400 Subject: [PATCH] bcachefs: Fix a cache coherency bug in bch2_subvolume_create() Subvolume deletion doesn't flush & evict the btree key cache - ideally it would, but that's tricky, so instead bch2_subvolume_create() needs to make sure the slot doesn't exist in the key cache to avoid triggering assertions. Signed-off-by: Kent Overstreet --- fs/bcachefs/subvolume.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/bcachefs/subvolume.c b/fs/bcachefs/subvolume.c index d1c111050c35c..9bd8d61c96fef 100644 --- a/fs/bcachefs/subvolume.c +++ b/fs/bcachefs/subvolume.c @@ -886,6 +886,7 @@ int bch2_subvolume_create(struct btree_trans *trans, u64 inode, u32 *new_snapshotid, bool ro) { + struct bch_fs *c = trans->c; struct btree_iter dst_iter, src_iter = (struct btree_iter) { NULL }; struct bkey_i_subvolume *new_subvol = NULL; struct bkey_i_subvolume *src_subvol = NULL; @@ -897,7 +898,13 @@ int bch2_subvolume_create(struct btree_trans *trans, u64 inode, BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k, ret) { if (bkey_cmp(k.k->p, SUBVOL_POS_MAX) > 0) break; - if (bkey_deleted(k.k)) + + /* + * bch2_subvolume_delete() doesn't flush the btree key cache - + * ideally it would but that's tricky + */ + if (bkey_deleted(k.k) && + !bch2_btree_key_cache_find(c, BTREE_ID_subvolumes, dst_iter.pos)) goto found_slot; } @@ -925,7 +932,7 @@ found_slot: goto err; if (k.k->type != KEY_TYPE_subvolume) { - bch_err(trans->c, "subvolume %u not found", src_subvolid); + bch_err(c, "subvolume %u not found", src_subvolid); ret = -ENOENT; goto err; } -- 2.30.2