3.16.78-rc1 review patch. If anyone has any objections, please let me know.
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From: ZhangXiaoxu zhangxiaoxu5@huawei.com
commit e4f9d6013820d1eba1432d51dd1c5795759aa77f upstream.
When btree_split_beneath() splits a node to two new children, it will allocate two blocks: left and right. If right block's allocation failed, the left block will be unlocked and marked dirty. If this happened, the left block'ss content is zero, because it wasn't initialized with the btree struct before the attempot to allocate the right block. Upon return, when flushing the left block to disk, the validator will fail when check this block. Then a BUG_ON is raised.
Fix this by completely initializing the left block before allocating and initializing the right block.
Fixes: 4dcb8b57df359 ("dm btree: fix leak of bufio-backed block in btree_split_beneath error path") Signed-off-by: ZhangXiaoxu zhangxiaoxu5@huawei.com Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/md/persistent-data/dm-btree.c | 31 ++++++++++++++------------- 1 file changed, 16 insertions(+), 15 deletions(-)
--- a/drivers/md/persistent-data/dm-btree.c +++ b/drivers/md/persistent-data/dm-btree.c @@ -533,39 +533,40 @@ static int btree_split_beneath(struct sh
new_parent = shadow_current(s);
+ pn = dm_block_data(new_parent); + size = le32_to_cpu(pn->header.flags) & INTERNAL_NODE ? + sizeof(__le64) : s->info->value_type.size; + + /* create & init the left block */ r = new_block(s->info, &left); if (r < 0) return r;
+ ln = dm_block_data(left); + nr_left = le32_to_cpu(pn->header.nr_entries) / 2; + + ln->header.flags = pn->header.flags; + ln->header.nr_entries = cpu_to_le32(nr_left); + ln->header.max_entries = pn->header.max_entries; + ln->header.value_size = pn->header.value_size; + memcpy(ln->keys, pn->keys, nr_left * sizeof(pn->keys[0])); + memcpy(value_ptr(ln, 0), value_ptr(pn, 0), nr_left * size); + + /* create & init the right block */ r = new_block(s->info, &right); if (r < 0) { unlock_block(s->info, left); return r; }
- pn = dm_block_data(new_parent); - ln = dm_block_data(left); rn = dm_block_data(right); - - nr_left = le32_to_cpu(pn->header.nr_entries) / 2; nr_right = le32_to_cpu(pn->header.nr_entries) - nr_left;
- ln->header.flags = pn->header.flags; - ln->header.nr_entries = cpu_to_le32(nr_left); - ln->header.max_entries = pn->header.max_entries; - ln->header.value_size = pn->header.value_size; - rn->header.flags = pn->header.flags; rn->header.nr_entries = cpu_to_le32(nr_right); rn->header.max_entries = pn->header.max_entries; rn->header.value_size = pn->header.value_size; - - memcpy(ln->keys, pn->keys, nr_left * sizeof(pn->keys[0])); memcpy(rn->keys, pn->keys + nr_left, nr_right * sizeof(pn->keys[0])); - - size = le32_to_cpu(pn->header.flags) & INTERNAL_NODE ? - sizeof(__le64) : s->info->value_type.size; - memcpy(value_ptr(ln, 0), value_ptr(pn, 0), nr_left * size); memcpy(value_ptr(rn, 0), value_ptr(pn, nr_left), nr_right * size);