On Thu, Mar 31, 2016 at 10:59:25AM +0200, Jan Kara wrote:

On Wed 30-03-16 16:01:29, Ross Zwisler wrote:

quoted

I've hit an issue in my testing which I believe to be related to the ext4
block allocator when using the DAX mount option.  I originally found this
issue with the generic/102 xfstest, but have reduced it to the minimal
reproducer at the bottom of this email.  I've been able to reproduce this with
both BRD and with PMEM as the underlying block device.

For this test we're running in a very small filesystem, only 512 MiB.  We
fallocate() 400 MiB of that space, unlink the file, then try and rewrite that
400 MiB file one chunk at a time.

What actually happens is that during the rewrite we run out of memory and the
DAX call to get_block() in dax_io() fails with -ENOSPC.

Yes, I have already sent a fix for this bug here:

http://www.spinics.net/lists/linux-ext4/msg51649.html

Ted, can you please pick it up? Thanks!

								Honza

Yay!

Ted, you can add my

Tested-by: Ross Zwisler <redacted>

to that patch.

Thanks for the fix, Jan!