From: Zhang Yi <yi.zhang@huawei.com> hulk inclusion category: bugfix bugzilla: 186216, https://gitee.com/openeuler/kernel/issues/I4PW7R CVE: NA -------------------------------- The same to commit 1c2d14212b15 ("ext2: Fix underflow in ext2_max_size()") in ext2 filesystem, ext4 driver has the same issue with 64K block size and ^huge_file, fix this issue the same as ext2. This patch also revert commit 75ca6ad408f4 ("ext4: fix loff_t overflow in ext4_max_bitmap_size()") because it's no longer needed. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Conflicts: fs/ext4/super.c Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Yang Erkun <yangerkun@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- fs/ext4/super.c | 46 +++++++++++++++++++++++++++++++--------------- 1 file changed, 31 insertions(+), 15 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 59637e70f9e32..8f9d60ec607ea 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2958,9 +2958,10 @@ static loff_t ext4_max_size(int blkbits, int has_huge_files) */ static loff_t ext4_max_bitmap_size(int bits, int has_huge_files) { - loff_t res = EXT4_NDIR_BLOCKS; + loff_t upper_limit, res = EXT4_NDIR_BLOCKS; int meta_blocks; - loff_t upper_limit; + unsigned int ppb = 1 << (bits - 2); + /* This is calculated to be the largest file size for a dense, block * mapped file such that the file's total number of 512-byte sectors, * including data and all indirect blocks, does not exceed (2^48 - 1). @@ -2991,23 +2992,38 @@ static loff_t ext4_max_bitmap_size(int bits, int has_huge_files) } - /* indirect blocks */ - meta_blocks = 1; - /* double indirect blocks */ - meta_blocks += 1 + (1LL << (bits-2)); - /* tripple indirect blocks */ - meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2))); - - upper_limit -= meta_blocks; - upper_limit <<= bits; - + /* Compute how many blocks we can address by block tree */ 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 + meta_blocks <= upper_limit) + goto check_lfs; + + res = upper_limit; + /* How many metadata blocks are needed for addressing upper_limit? */ + upper_limit -= EXT4_NDIR_BLOCKS; + /* indirect blocks */ + meta_blocks = 1; + upper_limit -= ppb; + /* double indirect blocks */ + if (upper_limit < ppb * ppb) { + meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb); + res -= meta_blocks; + goto check_lfs; + } + meta_blocks += 1 + ppb; + upper_limit -= ppb * ppb; + /* tripple indirect blocks for the rest */ + meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb) + + DIV_ROUND_UP(upper_limit, ppb*ppb); + res -= meta_blocks; +check_lfs: res <<= bits; - if (res > upper_limit) - res = upper_limit; - if (res > MAX_LFS_FILESIZE) res = MAX_LFS_FILESIZE; -- 2.25.1