ext4 had a regression where it double-accounted used blocks
if you fallocated on top of delalloc blocks. Ted sent a
c program to exploit it (see "fsstress-induced corruption reproduced"
on linux-ext4 on 12/31/2009) and it's trivial to do the same thing
within the xfstests framework using xfs_io.
This also changes the handcrafted xfs_io tests to use the
_require_xfs_io_falloc helper, not sure how that got missed.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
New test to test basic mixed fallocate + read & write,
includes a couple regression tests for bugs that ext4
hit. Uses xfs_io to generate fallocate calls, so requires
git xfsprogs and very recent glibc at this point.
Ext4 folks, this is hopefully a reasonable example of
how to add a new test. :)
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>