On Thu, Jun 7, 2012 at 3:54 PM, Ted Ts'o <tytso@xxxxxxx> wrote: > On Thu, Jun 07, 2012 at 03:40:40PM -0700, Kees Cook wrote: >> >> FWIW, I was building the filesystem that triggered this as ext4: >> >> mkfs.ext4 -T default -m 0 -O ^huge_file,^flex_bg -E >> discard,lazy_itable_init /dev/mapper/... > > Ouy of curiosity, was there a reason you chose those particular file > system parameters? It's a surprising set, because if you're starting > with a fresh file system, enabling flex_bg produces a more optimal > file system layout. The intent of this was to create a small (64M) initial filesystem as fast as possible that could be resized (to 3G) on the fly later. (The performance of the filesystem did not need to be optimized, just the speed of creation so that the create+mount would happen as fast as possible, to unblock things waiting for this filesystem to exist.) In the more common situation, it was built also with: -b 4096 ... -E ...,resize=MMM ... [device] NNN where MMM > NNN. And an online resize would be started a bit after it was created, growing it up to MMM. -Kees -- Kees Cook Chrome OS Security -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
