Re: [PATCH 4.19 067/105] ext4: protect journal inodes blocks using block_validity

On Mon 2019-05-20 14:14:13, Greg Kroah-Hartman wrote:

From: Theodore Ts'o tytso@mit.edu

commit 345c0dbf3a30872d9b204db96b5857cd00808cae upstream.

Add the blocks which belong to the journal inode to block_validity's system zone so attempts to deallocate or overwrite the journal due a corrupted file system where the journal blocks are also claimed by another inode.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202879 Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

+static int ext4_protect_reserved_inode(struct super_block *sb, u32 ino) +{

• struct inode *inode;
• struct ext4_sb_info *sbi = EXT4_SB(sb);
• struct ext4_map_blocks map;
• u32 i = 0, err = 0, num, n;
• if ((ino < EXT4_ROOT_INO) ||

•    (ino > le32_to_cpu(sbi->s_es->s_inodes_count)))
  

• return -EINVAL;
  

• inode = ext4_iget(sb, ino, EXT4_IGET_SPECIAL);
• if (IS_ERR(inode))

• return PTR_ERR(inode);
  

• num = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
• while (i < num) {

• map.m_lblk = i;
  

• map.m_len = num - i;
  

• n = ext4_map_blocks(NULL, inode, &map, 0);
  

• if (n < 0) {
  

• 	err = n;
  

• 	break;
  

• }
  

n is unsigned, so this can not happen. Commit 102/ actually fixes this up. Should they be merged together? Pavel