From 9b9a3270092bf8030dbe21ce90b2d0c8d98d33c7 Mon Sep 17 00:00:00 2001 From: Alan Huang Date: Fri, 13 Jun 2025 21:19:50 +0800 Subject: [PATCH] bcachefs: Don't allocate new memory when mempool is exhausted Allocating new memory when mempool is exhausted is too complicated, just return ENOMEM is fine. memcpy is not needed, since there might be pointers point to the old memory, that's the bug. Signed-off-by: Alan Huang Signed-off-by: Kent Overstreet --- fs/bcachefs/btree_iter.c | 29 ++++------------------------- 1 file changed, 4 insertions(+), 25 deletions(-) diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c index b586ecf2fdfa..55de2e474705 100644 --- a/fs/bcachefs/btree_iter.c +++ b/fs/bcachefs/btree_iter.c @@ -3217,28 +3217,8 @@ void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size, unsigned long } if (trans->used_mempool) { - if (trans->mem_bytes >= new_bytes) - goto out_change_top; - - /* No more space from mempool item, need malloc new one */ - new_mem = kmalloc(new_bytes, GFP_NOWAIT|__GFP_NOWARN); - if (unlikely(!new_mem)) { - bch2_trans_unlock(trans); - - new_mem = kmalloc(new_bytes, GFP_KERNEL); - if (!new_mem) - return ERR_PTR(-BCH_ERR_ENOMEM_trans_kmalloc); - - ret = bch2_trans_relock(trans); - if (ret) { - kfree(new_mem); - return ERR_PTR(ret); - } - } - memcpy(new_mem, trans->mem, trans->mem_top); - trans->used_mempool = false; - mempool_free(trans->mem, &c->btree_trans_mem_pool); - goto out_new_mem; + EBUG_ON(trans->mem_bytes >= new_bytes); + return ERR_PTR(-BCH_ERR_ENOMEM_trans_kmalloc); } new_mem = krealloc(trans->mem, new_bytes, GFP_NOWAIT|__GFP_NOWARN); @@ -3249,7 +3229,6 @@ void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size, unsigned long if (!new_mem && new_bytes <= BTREE_TRANS_MEM_MAX) { new_mem = mempool_alloc(&c->btree_trans_mem_pool, GFP_KERNEL); new_bytes = BTREE_TRANS_MEM_MAX; - memcpy(new_mem, trans->mem, trans->mem_top); trans->used_mempool = true; kfree(trans->mem); } @@ -3264,7 +3243,7 @@ void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size, unsigned long if (ret) return ERR_PTR(ret); } -out_new_mem: + trans->mem = new_mem; trans->mem_bytes = new_bytes; @@ -3273,7 +3252,7 @@ out_new_mem: return ERR_PTR(btree_trans_restart_ip(trans, BCH_ERR_transaction_restart_mem_realloced, _RET_IP_)); } -out_change_top: + bch2_trans_kmalloc_trace(trans, size, ip); p = trans->mem + trans->mem_top; -- 2.50.1