On Mon, 7 May 2007 15:21:04 -0700 Andreas Dilger <adilger@xxxxxxxxxxxxx> wrote: > On May 07, 2007 13:58 -0700, Andrew Morton wrote: > > Final point: it's fairly disappointing that the present implementation is > > ext4-only, and extent-only. I do think we should be aiming at an ext4 > > bitmap-based implementation and an ext3 implementation. > > Actually, this is a non-issue. The reason that it is handled for extent-only > is that this is the only way to allocate space in the filesystem without > doing the explicit zeroing. For other filesystems (including ext3 and > ext4 with block-mapped files) the filesystem should return an error (e.g. > -EOPNOTSUPP) and glibc will do manual zero-filling of the file in userspace. hrm, spose so. It can be a bit suboptimal from the layout POV. The reservations code will largely save us here, but kernel support might make it a bit better. Totally blowing pagecache could be a problem. Fixable in userspace by using sync_file_range()+fadvise() or O_DIRECT, but I bet it doesn't. - 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
