Re: [PATCH v2 0/2][RESEND] btrfs-progs: handle orphan directories properly

[David Sterba <dsterba@suse.cz>]

On Tue, Feb 22, 2022 at 05:24:29PM -0500, Josef Bacik wrote:
> v1->v2:
> - use "is_orphan" not "has_orphan_item" in the mode-lowmem code.  Somehow the
>   compiler didn't warn me of this until I switched to a different branch.
> 
> --- Original email ---
> Hello,
> 
> While implementing the garbage collection tree I started getting btrfsck errors
> when a test would do rm -rf DIRECTORY and then immediately unmount.  This is
> because we stop processing GC items during umount, and thus we left the
> directory with an nlink == 0 and all of its children in the fs tree.
> 
> However this isn't a problem with just the GC tree, we can have this happen if
> we fail to do the eviction work at evict time, and we leave the orphan entry in
> place on disk.  btrfsck properly ignores problems with inodes that have orphan
> items, except for directory inodes.
> 
> Fix this by making sure we don't add any backrefs we find from directory inodes
> that we've find the inode item for and have an nlink == 0.
> 
> I generated a test image for this by simply skipping the
> btrfs_truncate_inode_items() work in evict in a kernel and rm -rf'ing a
> directory on a test file system.
> 
> With this patch both make test-check and make test-check-lowmem pass all the
> tests, including the new testcase.  Thanks,
> 
> Josef
> 
> Josef Bacik (2):
>   btrfs-progs: handle orphan directories properly
>   btrfs-progs: add a test to check orphaned directories

Added to devel, thanks.