tytso@xxxxxxx wrote: > On Mon, Mar 29, 2010 at 09:48:50AM -0500, Eric Sandeen wrote: >> CaT wrote: >>> Using kernel 2.6.33.1. Am rsyncing from /data/mirror (a raid0 mount) to >>> /dev/sda1 (a usb HD). Both filesystems formatted as ext3 but mounted as >>> ext4. /mnt filesystem is only being added to and currently large files >>> (iso files 700MB-4.4GB) are being copied. When I remounted /mnt as ext3 >>> I could not duplicate the issue and the amount of disk used stabilised >>> at 182G. The df results, whilst /mnt is mounted as ext4, are below: >> I would say this is likely speculative allocation due to delalloc >> (ext4 has to reserve worst-case metadata amounts to prepare for >> delalloc writeback). When the file data actually gets written out, >> the worst-case reservation is freed up again. We also flush and >> switch to nodelalloc when the filesystem is pretty close to full. >> see ext4_nonda_switch() for example. >> >> This looks pretty severe though, more than I would expect >> from that behavior. > > This is fixed in commit d330a5bef, which which got merged post > 2.6.34-rc2, and which we need to get into 2.6.33 stable. If you > cherry-pick that commit, I think you'll see that it fixes this > problem. Oh, right, spaced that one. Thanks for the reminder Ted. :) And from now on ext3-mounted-as-ext4 is special-cased so you won't get delalloc, and you won't get this behavior at all (nor will you get any delalloc benefits, FWIW). Thanks, -Eric > - Ted -- 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
