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bcachefs: Don't allocate new memory when mempool is exhausted

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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 <mmpgouride@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Alan Huang
2025-06-13 21:19:50 +08:00
committed by Kent Overstreet
parent 3bd6f8aeae
commit 9b9a327009
1 changed files with 4 additions and 25 deletions
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29
fs/bcachefs/btree_iter.c
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@@ -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;