I still think that using resize2fs and removing/adding the journal provides the clearest way to create a small image. The only drawback is that this needs some post-processing steps after the image is written, so it may not be suitable for some workflows. Cheers, Andreas On 2011-07-27, at 10:40 AM, Round Robinjp <roundrobinjp@xxxxxxxxxxx> wrote: >>> The flash will then contain _random_ data in the non-used blocks. >>> That is not a problem, right? >> >> Nope. So long as the previously written (random) data on the card >> doesn't contain anything security sensitive. > > I understood. > >>> Although I have very small amount of files in my 4G image, >>> I see that the image has almost no zero-filled blocks. >>> Is that normal for ext4? >> >> It depends on how you created the image. > > I create the image like this: > > dd if=/dev/zero of=a.img bs=4096 count=1048576 > mkfs.ext4 a.img > mount -t ext4 -o loop a.img /mnt > cp -a /foo/* /mnt/ > umount /mnt > >>> Can zerofree.c recognize them as non-used blocks? >> >> Yes, it uses the block allocation bitmaps to understand what is used >> and non-used. > > Great. > > Thanks > Round > -- > 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 -- 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
