From: Zhang Yi <yi.zhang@huawei.com> stable inclusion from stable-v5.10.110 commit 9ffa07c699a72fc351620ee3cf6797d1a8abe37f bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 50b3a818991074177a56c87124c7a7bdf5fa4f67 ] We need to calculate the max file size accurately if the total blocks that can address by block tree exceed the upper_limit. But this check is not correct now, it only compute the total data blocks but missing metadata blocks are needed. So in the case of "data blocks < upper_limit && total blocks > upper_limit", we will get wrong result. Fortunately, this case could not happen in reality, but it's confused and better to correct the computing. bits data blocks metadatablocks upper_limit 10 16843020 66051 2147483647 11 134480396 263171 1073741823 12 1074791436 1050627 536870911 (*) 13 8594130956 4198403 268435455 (*) 14 68736258060 16785411 134217727 (*) 15 549822930956 67125251 67108863 (*) 16 4398314962956 268468227 33554431 (*) [*] Need to calculate in depth. Fixes: 1c2d14212b15 ("ext2: Fix underflow in ext2_max_size()") Link: https://lore.kernel.org/r/20220212050532.179055-1-yi.zhang@huawei.com Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yu Liao <liaoyu15@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- fs/ext2/super.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/ext2/super.c b/fs/ext2/super.c index 09f1fe676972..b6314d3c6a87 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -756,8 +756,12 @@ static loff_t ext2_max_size(int bits) res += 1LL << (bits-2); res += 1LL << (2*(bits-2)); res += 1LL << (3*(bits-2)); + /* Compute how many metadata blocks are needed */ + meta_blocks = 1; + meta_blocks += 1 + ppb; + meta_blocks += 1 + ppb + ppb * ppb; /* Does block tree limit file size? */ - if (res < upper_limit) + if (res + meta_blocks <= upper_limit) goto check_lfs; res = upper_limit; -- 2.20.1