Re: [PATCH] delete obsolete function btrfs_print_tree()

["Holger Hoffstätte" <holger.hoffstaette@googlemail.com>]

On 04/04/16 15:56, David Sterba wrote:
> On Fri, Mar 25, 2016 at 03:53:17PM +0100, Holger Hoffstätte wrote:
>> Dan Carpenter's static checker recently found missing IS_ERR handling
>> in print-tree.c:btrfs_print_tree(). While looking into this I found that
>> this function is no longer called anywhere and was moved to btrfs-progs
>> long ago. It can simply be removed.
> 
> I'm not sure, the function could be used for debugging, and it's hard to

..but is it? So far nobody has complained.

> say if we'll ever need it.  Printing the whole tree to the system log
> would produce a lot of text so some manual filtering would be required,
> the function could serve as a template.

The original problem of missing error handling from btrfs_read_tree_block()
remains as well. I don't remember if that also was true for the btrfs-progs
counterpart, but in in any case I didn't really know what to do there.
Print an error? silently ignore the stripe? abort? When I realized that the
function was not called anywhere, deleting it seemed more effective.

Under what circumstances would the in-kernel function be more
practical or useful than the userland tool? It does the same, won't disturb
or wedge the kernel further, is up-to-date and can be scripted.
I agree that in-place filtering (while iterating) would be nice to have,
but that's also a whole different problem and would IMHO also be better
suited for userland.

When in doubt cut it out.

Holger