On Tue, Sep 25, 2012 at 11:22:07AM +0200, Jan Kara wrote: > Currently, iterate_bdevs() skips block devices without any pages in page > cache. That is fine for current use by sync(2) but may be rather surprising > for possible future users. So move the checks from iterate_bdevs() to > callback functions used by sync(2). *snort* You know, testing is occasionally useful. Sure, it's boring, but once in a while one gets amusing results. The thing is, the only reason why the sucker hadn't oopsed *without* that patch was that the only non-bdev on that inode list happened to have zero in ->mapping->nr_pages. Reliably. What we'd accidentally avoided (until that patch) was stepping on the root directory of bdev filesystem. I_BDEV() on it is fine - it's allocated in a regular way, so we are not doing anything bad with container_of() here. However, it never went through bdget(), obviously - just new_inode(). And it has I_BDEV(inode)->bd_inode == NULL. The rest is obious... More interesting question is whether inode list is the right approach. After all, there's a list with suggestive name - all_bdevs... -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
