Commit 36f9ef10 authored by Hongbo Li's avatar Hongbo Li Committed by Kent Overstreet
Browse files

bcachefs: fix trans->mem realloc in __bch2_trans_kmalloc 



The old code doesn't consider the mem alloced from mempool when call
krealloc on trans->mem. Also in bch2_trans_put, using mempool_free to
free trans->mem by condition "trans->mem_bytes == BTREE_TRANS_MEM_MAX"
is inaccurate when trans->mem was allocated by krealloc function.
Instead, we use used_mempool stuff to record the situation, and realloc
or free the trans->mem in elegant way.

Also, after krealloc failed in __bch2_trans_kmalloc, the old data
should be copied to the new buffer when alloc from mempool_alloc.

Fixes: 31403dca ("bcachefs: optimize __bch2_trans_get(), kill DEBUG_TRANSACTIONS")
Signed-off-by: default avatarHongbo Li <lihongbo22@huawei.com>
Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 57339b24

fs/bcachefs/btree_iter.c

+30 −3
Original line number Diff line number Diff line
@@ -2790,6 +2790,31 @@ void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size) 
	struct btree_transaction_stats *s = btree_trans_stats(trans);

	s->max_mem = max(s->max_mem, new_bytes);



	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;

	}



	new_mem = krealloc(trans->mem, new_bytes, GFP_NOWAIT|__GFP_NOWARN);

	if (unlikely(!new_mem)) {

		bch2_trans_unlock(trans);
@@ -2798,6 +2823,8 @@ void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size) 
		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);

		}
@@ -2811,7 +2838,7 @@ void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size) 
		if (ret)

			return ERR_PTR(ret);

	}



out_new_mem:

	trans->mem = new_mem;

	trans->mem_bytes = new_bytes;
@@ -2819,7 +2846,7 @@ void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size) 
		trace_and_count(c, trans_restart_mem_realloced, trans, _RET_IP_, new_bytes);

		return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_mem_realloced));

	}



out_change_top:

	p = trans->mem + trans->mem_top;

	trans->mem_top += size;

	memset(p, 0, size);
@@ -3093,7 +3120,7 @@ void bch2_trans_put(struct btree_trans *trans) 
	if (paths_allocated != trans->_paths_allocated)

		kvfree_rcu_mightsleep(paths_allocated);



	if (trans->mem_bytes == BTREE_TRANS_MEM_MAX)

	if (trans->used_mempool)

		mempool_free(trans->mem, &c->btree_trans_mem_pool);

	else

		kfree(trans->mem);