bcachefs: fix race in bch2_btree_node_evict()

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/btree_cache.c b/fs/bcachefs/btree_cache.c
index 84474324dba9b508141f0e886bafbd8a95d47537..c7f156320a35dc194d3e3d1c28fb6ef40fc6831c 100644 (file)
--- a/fs/bcachefs/btree_cache.c
+++ b/fs/bcachefs/btree_cache.c
@@ -1148,6 +1148,8 @@ wait_on_io:
 
        btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_intent);
        btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_write);
+       if (unlikely(b->hash_val != btree_ptr_hash_val(k)))
+               goto out;
 
        if (btree_node_dirty(b)) {
                __bch2_btree_node_write(c, b, BTREE_WRITE_cache_reclaim);
@@ -1162,7 +1164,7 @@ wait_on_io:
        btree_node_data_free(c, b);
        bch2_btree_node_hash_remove(bc, b);
        mutex_unlock(&bc->lock);
-
+out:
        six_unlock_write(&b->c.lock);
        six_unlock_intent(&b->c.lock);
 }