jim owens wrote: > du rules In general, hard :-) See the difficulties reporting process memory usage given shared libraries for how tricky it gets. Imho, the simplest is for du to report how much space it would take if all the files were fully unCOWed, either by being modified or copied to another filesystem. In other words, just return the data blocks assigned to a file as usual; the COW difference is the same block can be assigned to more than one file. Sometimes knowing the unCOWed space would even be useful. Of course knowing the COWed space is also useful. (Both together would give you a nice feel for how much space COW is saving.) I suspect that would need changes to du to give useful answers (and similar changes to "Disk Usage Analyzer" if you like that tool). du detects hard links by i_nlink!=1 and inode number, and merges the accounting. For partially shared files, I'm not sure how best to get the right information out. FIEMAP is inherently a lot slower than stat() because it can do much more disk access, and it might not always work (depending on how data is represented on disk), and it might not always be permitted. Worse, there's no i_nlink!=1 equivalent to decide when FIEMAP does not need to be called. -- Jamie -- 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
