protect-add-journal-inode-blocks-using-block_validity

   1 ext4: protect journal inode's blocks using block_validity
   2
   3 Add the blocks which belong to the journal inode to block_validity's
   4 system zone so attempts to deallocate or overwrite the journal due a
   5 corrupted file system where the journal blocks are also claimed by
   6 another inode.
   7
   8 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202879
   9 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  10 Cc: stable@kernel.org
  11 ---
  12  fs/ext4/block_validity.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
  13  fs/ext4/inode.c          |  4 ++++
  14  2 files changed, 52 insertions(+)
  15
  16 diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
  17 index 913061c0de1b..9409b1e11a22 100644
  18 --- a/fs/ext4/block_validity.c
  19 +++ b/fs/ext4/block_validity.c
  20 @@ -137,6 +137,48 @@ static void debug_print_tree(struct ext4_sb_info *sbi)
  21         printk(KERN_CONT "\n");
  22  }
  23
  24 +static int ext4_protect_reserved_inode(struct super_block *sb, u32 ino)
  25 +{
  26 +       struct inode *inode;
  27 +       struct ext4_sb_info *sbi = EXT4_SB(sb);
  28 +       struct ext4_map_blocks map;
  29 +       u32 i = 0, err = 0, num, n;
  30 +
  31 +       if ((ino < EXT4_ROOT_INO) ||
  32 +           (ino > le32_to_cpu(sbi->s_es->s_inodes_count)))
  33 +               return -EINVAL;
  34 +       inode = ext4_iget(sb, ino, EXT4_IGET_SPECIAL);
  35 +       if (IS_ERR(inode))
  36 +               return PTR_ERR(inode);
  37 +       num = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
  38 +       while (i < num) {
  39 +               map.m_lblk = i;
  40 +               map.m_len = num - i;
  41 +               n = ext4_map_blocks(NULL, inode, &map, 0);
  42 +               if (n < 0) {
  43 +                       err = n;
  44 +                       break;
  45 +               }
  46 +               if (n == 0) {
  47 +                       i++;
  48 +               } else {
  49 +                       if (!ext4_data_block_valid(sbi, map.m_pblk, n)) {
  50 +                               ext4_error(sb, "blocks %llu-%llu from inode %u "
  51 +                                          "overlap system zone", map.m_pblk,
  52 +                                          map.m_pblk + map.m_len - 1, ino);
  53 +                               err = -EFSCORRUPTED;
  54 +                               break;
  55 +                       }
  56 +                       err = add_system_zone(sbi, map.m_pblk, n);
  57 +                       if (err < 0)
  58 +                               break;
  59 +                       i += n;
  60 +               }
  61 +       }
  62 +       iput(inode);
  63 +       return err;
  64 +}
  65 +
  66  int ext4_setup_system_zone(struct super_block *sb)
  67  {
  68         ext4_group_t ngroups = ext4_get_groups_count(sb);
  69 @@ -171,6 +213,12 @@ int ext4_setup_system_zone(struct super_block *sb)
  70                 if (ret)
  71                         return ret;
  72         }
  73 +       if (ext4_has_feature_journal(sb) && sbi->s_es->s_journal_inum) {
  74 +               ret = ext4_protect_reserved_inode(sb,
  75 +                               le32_to_cpu(sbi->s_es->s_journal_inum));
  76 +               if (ret)
  77 +                       return ret;
  78 +       }
  79
  80         if (test_opt(sb, DEBUG))
  81                 debug_print_tree(sbi);
  82 diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
  83 index 190f0478582a..609c8366d029 100644
  84 --- a/fs/ext4/inode.c
  85 +++ b/fs/ext4/inode.c
  86 @@ -399,6 +399,10 @@ static int __check_block_validity(struct inode *inode, const char *func,
  87                                 unsigned int line,
  88                                 struct ext4_map_blocks *map)
  89  {
  90 +       if (ext4_has_feature_journal(inode->i_sb) &&
  91 +           (inode->i_ino ==
  92 +            le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
  93 +               return 0;
  94         if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
  95                                    map->m_len)) {
  96                 ext4_error_inode(inode, func, line, map->m_pblk,