Re: [PATCH] btrfs: make sure that WRITTEN is set on all metadata blocks

[David Sterba <dsterba@suse.cz>]

On Thu, May 02, 2024 at 07:15:36AM +0930, Qu Wenruo wrote:
> 
> 
> 在 2024/4/29 22:33, Josef Bacik 写道:
> > We previously would call btrfs_check_leaf() if we had the check
> > integrity code enabled, which meant that we could only run the extended
> > leaf checks if we had WRITTEN set on the header flags.
> >
> > This leaves a gap in our checking, because we could end up with
> > corruption on disk where WRITTEN isn't set on the leaf, and then the
> > extended leaf checks don't get run which we rely on to validate all of
> > the item pointers to make sure we don't access memory outside of the
> > extent buffer.
> >
> > However, since 732fab95abe2 ("btrfs: check-integrity: remove
> > CONFIG_BTRFS_FS_CHECK_INTEGRITY option") we no longer call
> > btrfs_check_leaf() from btrfs_mark_buffer_dirty(), which means we only
> > ever call it on blocks that are being written out, and thus have WRITTEN
> > set, or that are being read in, which should have WRITTEN set.
> >
> > Add checks to make sure we have WRITTEN set appropriately, and then make
> > sure __btrfs_check_leaf() always does the item checking.  This will
> > protect us from file systems that have been corrupted and no longer have
> > WRITTEN set on some of the blocks.
> >
> > Reported-by: lei lu <llfamsec@gmail.com>
> > Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> 
> Reviewed-by: Qu Wenruo <wqu@suse.com>
> 
> Is there any real world bug report on this? Or just some code reading
> exposed this problem?

There is a report.