Re: [PATCH] fs: Detect API misuse of i_op->lookup

[Al Viro]

On Sun, Jan 25, 2015 at 10:57:40PM +0100, Richard Weinberger wrote:
> Hunting down a refcount issue in an out-of-tree filesystem uncovered
> that its lookup function directly returned the dentry which was passed to it.
> Add a BUG_ON() to detect such misuse in future.

In principle, it's not a bug.  You *must* grab a reference to dentry before
returning it, but you can very well decide to return the one you've got -
any place where have ->lookup() return NULL has every right to become
return dget(dentry).
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/