Re: [PATCH] btrfs: Rework error detection in init_tree_roots

[David Sterba <dsterba@suse.cz>]

On Tue, Aug 04, 2020 at 06:02:58PM +0300, Nikolay Borisov wrote:
> 
> 
> On 4.08.20 г. 15:58 ч., Johannes Thumshirn wrote:
> > On 04/08/2020 09:32, Nikolay Borisov wrote:
> >> @@ -2645,17 +2645,16 @@ static int __cold init_tree_roots(struct btrfs_fs_info *fs_info)
> >>  		level = btrfs_super_root_level(sb);
> >>  		tree_root->node = read_tree_block(fs_info, btrfs_super_root(sb),
> >>  						  generation, level, NULL);
> >> -		if (IS_ERR(tree_root->node) ||
> >> -		    !extent_buffer_uptodate(tree_root->node)) {
> >> +		if (IS_ERR(tree_root->node)) {
> >>  			handle_error = true;
> >> +			ret = PTR_ERR(tree_root->node);
> >> +			tree_root->node = NULL;
> >> +			btrfs_warn(fs_info, "failed to read tree root");
> >> +			continue;
> > 
> > [...]
> > 
> >>  			btrfs_warn(fs_info, "failed to read tree root");
> >>  			continue;
> >>  		}
> > 
> > Now we're duplicating the warning message. I think it's better to have two 
> > distinct messages so we can differentiate which of the two failure cases happened.
> > 
> > The 2nd one could be something like "tree root eb not uptodate".
> 
> Sure, I'm happy too replace it with whatever is more informative. Will
> take another look at the code and see what I can derive.

The errors are different, IS_ERR is because the block was not read at
all for some reason, extent_buffer_uptodate is EIO in all other places
that do this kind of check.

Here it's EUCLEAN and it's been like that since the beginning but I
think it should be EIO.