On Tue, 6 Mar 2012, Ted Ts'o wrote: > On Fri, Mar 02, 2012 at 01:11:58PM +0100, Lukas Czerner wrote: > > Because the BLOCK_UNINIT is only set on mke2fs time and cleared when > > allocation from that group takes place we know that when set, there was > > not anything allocated from that group, hence there should not be anything > > to discard from the file system point of view. > > There's a really good reason to set BLOCK_UNINIT once we have noticed > that all of the blocks in the block group have been released.... > > If you have a 3TB HDD, running e2fsck takes 4 times as long if all of > the block groups have BLOCK_UNINIT cleared, compared to a freshly > mkfs'ed file system. As a result of my getting really annoyed at how > long it took in this case, I'm planning on making e2fsck clear > BLOCK_UNINIT if possible, so that subsequent e2fsck's (and dumpe2fs > and debugfs invocations) can also be fast. > > - Ted Ok, if there is a plan to implement that, I am fine with dropping th patches. But since this optimization would be helpful for discard, we can introduce BLOCK_DISCARDED/UNPROVISIONED flag maybe ? Which would be sen only after discard and cleared with the first allocation ? Thanks! -Lukas -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
