On 12/04/2012 07:22 AM, Theodore Ts'o wrote: > On Mon, Dec 03, 2012 at 11:46:07AM -0800, Darren Hart wrote: >>> Maybe Ted can confirm whether that is true or not. At least I recall >>> that the block allocator inside libext2fs was horrible, and creating >>> large files was problematic. >> >> Ted, can you confirm? > > The block allocator inside libext2fs is primitive; it will find the > first free block and use it. It should be OK for populating large > flash devices for file system images stored on flash devices (where > seeks don't matter so block group placement isn't a big deal), and > especially for fixed root file system images which are mounted > read-only and which tend to be updated only once in a while (i.e., in > the cases of Android system updates), and so you don't really care > about aligning file writes to eMMC erase blocks. > > It could certainly be made better, and for people who were trying to > use libext2fs with FUSE targetting hard drives, there are ample > opportunities for improvements..... > I think what I'm reading here is that if you care about having a filesystem that makes hardware specific optimizations, you're better off mounting the device and copying the filesystem over. In that case, plan on needing root access. > Creating large files shouldn't be a problem (unless what you mean is > ext4 huge files ala the huge file feature where the number of 512 > blocks exceeds 2**32, in which case you should probably test that case > if you care about it), and it certainly will create extents-based > files. Great, sounds like this approach is still viable. Thanks Ted! -- Darren Hart Intel Open Source Technology Center Yocto Project - Technical Lead - Linux Kernel -- 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
