On Thu, Mar 27, 2025 at 07:25:30PM +0100, Jan Kara wrote:
> On Thu 27-03-25 23:18:09, Ojaswin Mujoo wrote:
> > 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>
> > Signed-off-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
>
> Looks good. Feel free to add:
>
> Reviewed-by: Jan Kara <jack@xxxxxxx>
>
> One style nit below:
>
> > 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..8b048be14008 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)))
> > - return 0;
> > + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
> > +
> > + if (journal && inode == journal->j_inode)
> > + return 0;
>
> Bogus indentation here.
Thanks for the review Jan and for catching this. My bad, i missed
running checkpatch on this and somehow this looked okay in vim.
I'll fix this and quickly send a v3.
Regards,
ojaswin
>
> Honza
> --
> Jan Kara <jack@xxxxxxxx>
> SUSE Labs, CR
