Messages in this thread | | | Date | Wed, 23 Nov 2011 06:56:51 +1100 | From | Dave Chinner <> | Subject | Re: [3.2-rc2] loop device balance_dirty_pages_nr throttling hang |
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On Tue, Nov 22, 2011 at 08:17:07AM -0500, Theodore Tso wrote: > > On Nov 22, 2011, at 5:49 AM, Dave Chinner wrote: > > > But, I just noticed that the discard that mkfs.ext4 will result > > in all the extents being discarded in the underlying image file > > (due to the fact the loopback device now supports hole > > punching), so the previous state of the image file is getting > > trashed by the mkfs.ext4 execution, too. I think I already had a > > ext4 filesystem in some state before I started running this > > manual prealloc test.... > > Which version of mkfs.ext4 are you using? We've disabled the > discard by default (unless configured in via a command-line option > or a /etc/mke2fs.conf setting since no distribution apparently > wants to be responsible for running supplying a command that > causes a crap SSD to turning into a brick; personally, I'd blame > the manufacturer of the crap SSD, but….)
Whatever I've got installed on my test machines. The machien I reproduced the problem originally on with sparse files is runningi mke2fs 1.42-WIP (16-Oct-2011) which is the latest in Debian unstable, the other that is using a real 17TB array is running mke2fs 1.42-WIP (02-Jul-2011). I saw the discard occurring
BTW, on a 5PB sparse image file I get this error from the latest mke2fs above:
$ ls -lh /mnt/scratch/scratch.img -rw------- 1 root root 4.9P Nov 23 06:50 /mnt/scratch/scratch.img $ sudo mkfs.ext4 /dev/loop0 mke2fs 1.42-WIP (16-Oct-2011) /dev/loop0: Cannot create filesystem with requested number of inodes while setting up superblock $
This version does emit that it is discarding blocks:
$ sudo mkfs.ext4 /dev/loop0 mke2fs 1.42-WIP (16-Oct-2011) Discarding device blocks: done Filesystem label= .....
Cheers,
Dave. -- Dave Chinner david@fromorbit.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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