Block validity checks need to be skipped in case they are called for journal blocks since they are part of system's protected zone. Currently, this is done by checking inode->ino against sbi->s_es->s_journal_inum, which is a direct read from the ext4 sb buffer head. If someone modifies this underneath us then the s_journal_inum field might get corrupted. To prevent against this, change the check to directly compare the inode with journal->j_inode. **Slight change in behavior**: During journal init path, check_block_validity etc might be called for journal inode when sbi->s_journal is not set yet. In this case we now proceed with ext4_inode_block_valid() instead of returning early. Since systems zones have not been set yet, it is okay to proceed so we can perform basic checks on the blocks. Suggested-by: Baokun Li <libaokun1@xxxxxxxxxx> Reviewed-by: Baokun Li <libaokun1@xxxxxxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Reviewed-by: Zhang Yi <yi.zhang@xxxxxxxxxx> Signed-off-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx> --- ** Changes since v1 [2] ** - minor indentation fix - RVBs from Yi, Baokun & Jan (Thanks!) [2] https://lore.kernel.org/linux-ext4/c434eb50ee5161e23036d58a6166a7e216f6d6a0.1743097281.git.ojaswin@xxxxxxxxxxxxx/ ** Changes since v1 [1] ** - instead of using an sbi field direction check against jorunal->j_inode - let block validity perform basic checks on journal blocks as well during init path - kvm-xfstests quick tests are passing - commit header changed [1] https://lore.kernel.org/linux-ext4/d1a9328a41029f6210a1924b192a59afcd3c5cee.1741952406.git.ojaswin@xxxxxxxxxxxxx/ fs/ext4/block_validity.c | 5 ++--- fs/ext4/inode.c | 7 ++++--- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c index 87ee3a17bd29..e8c5525afc67 100644 --- a/fs/ext4/block_validity.c +++ b/fs/ext4/block_validity.c @@ -351,10 +351,9 @@ int ext4_check_blockref(const char *function, unsigned int line, { __le32 *bref = p; unsigned int blk; + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal; - if (ext4_has_feature_journal(inode->i_sb) && - (inode->i_ino == - le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum))) + if (journal && inode == journal->j_inode) return 0; while (bref < p+max) { diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 365d31004bd0..67429c50e5a0 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -384,10 +384,11 @@ static int __check_block_validity(struct inode *inode, const char *func, unsigned int line, struct ext4_map_blocks *map) { - if (ext4_has_feature_journal(inode->i_sb) && - (inode->i_ino == - le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum))) + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal; + + if (journal && inode == journal->j_inode) return 0; + if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) { ext4_error_inode(inode, func, line, map->m_pblk, "lblock %lu mapped to illegal pblock %llu " -- 2.48.1
