On Wed, Mar 17, 2021 at 05:23:31PM +0100, Jan Kara wrote:
> [Upstream commit ce9f24cccdc019229b70a5c15e2b09ad9c0ab5d1]
>
> Currently, system zones just track ranges of block, that are "important"
> fs metadata (bitmaps, group descriptors, journal blocks, etc.). This
> however complicates how extent tree (or indirect blocks) can be checked
> for inodes that actually track such metadata - currently the journal
> inode but arguably we should be treating quota files or resize inode
> similarly. We cannot run __ext4_ext_check() on such metadata inodes when
> loading their extents as that would immediately trigger the validity
> checks and so we just hack around that and special-case the journal
> inode. This however leads to a situation that a journal inode which has
> extent tree of depth at least one can have invalid extent tree that gets
> unnoticed until ext4_cache_extents() crashes.
>
> To overcome this limitation, track inode number each system zone belongs
> to (0 is used for zones not belonging to any inode). We can then verify
> inode number matches the expected one when verifying extent tree and
> thus avoid the false errors. With this there's no need to to
> special-case journal inode during extent tree checking anymore so remove
> it.
>
> Fixes: 0a944e8a6c66 ("ext4: don't perform block validity checks on the journal inode")
> Reported-by: Wolfgang Frisch <wolfgang.frisch@xxxxxxxx>
> Reviewed-by: Lukas Czerner <lczerner@xxxxxxxxxx>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> Link: https://lore.kernel.org/r/20200728130437.7804-4-jack@xxxxxxx
> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Now queued up, thanks!
greg k-h
