On Tue, Apr 07, 2015 at 11:56:50AM +1000, Dave Chinner wrote: > From: Dave Chinner <[email protected]> > > The "brd" kernel ram disk abuses BLKFLSBUF to mean "free all memory > in the ram drive" when in fact it actually means "flush all dirty > buffers to stable storage". the brd driver ignores BLKFLSBUF if > there is an active reference to the block device, (e.g. a fs is > mounted on it), but when a device is layered over the top of it > (e.g. dm-flakey, lvm devices, etc) then the applications and > filesystems hold references to the upper device, not the brd device. > Hence when the upper device passes down BLKFLSBUF to brd, it removes > all the pages in the brd, effectively erasing it. This causes all > sorts of problems..... > > Fix this by black listing "/dev/ramXXX" devices from tests that > require DM in some way. The _requires_sane_bdev_flush() macro is > called by the _requires_dm.... checks so that we don't have to > remember to add this to all new tests that use dm in some way. > > Signed-off-by: Dave Chinner <[email protected]> > ---
Sounds good to me... looks like we have a similar check in libxfs (platform_flush_device()). Reviewed-by: Brian Foster <[email protected]> > common/rc | 34 +++++++++++++++++++++++----------- > tests/generic/081 | 1 - > 2 files changed, 23 insertions(+), 12 deletions(-) > > diff --git a/common/rc b/common/rc > index c5db0dd..ca8da7f 100644 > --- a/common/rc > +++ b/common/rc > @@ -1305,26 +1305,38 @@ _require_block_device() > fi > } > > +# brd based ram disks erase the device when they receive a flush command > when no > +# active references are present. This causes problems for DM devices sitting > on > +# top of brd devices as DM doesn't hold active references to the brd device. > +_require_sane_bdev_flush() > +{ > + echo $1 | grep -q "^/dev/ram[0-9]\+$" > + if [ $? -eq 0 ]; then > + _notrun "This test requires a sane block device flush" > + fi > +} > + > # this test requires the device mapper flakey target > # > _require_dm_flakey() > { > - # require SCRATCH_DEV to be a valid block device > - _require_block_device $SCRATCH_DEV > - _require_command "$DMSETUP_PROG" dmsetup > + # require SCRATCH_DEV to be a valid block device with sane BLKFLSBUF > + # behaviour > + _require_block_device $SCRATCH_DEV > + _require_sane_bdev_flush $SCRATCH_DEV > + _require_command "$DMSETUP_PROG" dmsetup > > - modprobe dm-flakey >/dev/null 2>&1 > - $DMSETUP_PROG targets | grep flakey >/dev/null 2>&1 > - if [ $? -eq 0 ] > - then > - : > - else > - _notrun "This test requires dm flakey support" > - fi > + modprobe dm-flakey >/dev/null 2>&1 > + $DMSETUP_PROG targets | grep flakey >/dev/null 2>&1 > + if [ $? -ne 0 ]; then > + _notrun "This test requires dm flakey support" > + fi > } > > _require_dm_snapshot() > { > + _require_block_device $SCRATCH_DEV > + _require_sane_bdev_flush $SCRATCH_DEV > _require_command "$DMSETUP_PROG" dmsetup > modprobe dm-snapshot >/dev/null 2>&1 > $DMSETUP_PROG targets | grep -q snapshot > diff --git a/tests/generic/081 b/tests/generic/081 > index e242c4c..5d38c11 100755 > --- a/tests/generic/081 > +++ b/tests/generic/081 > @@ -50,7 +50,6 @@ _supported_os Linux > _require_test > _require_scratch_nocheck > _require_dm_snapshot > -_require_block_device $SCRATCH_DEV > _require_command $LVM_PROG lvm > > echo "Silence is golden" > -- > 2.0.0 > > -- > To unsubscribe from this list: send the line "unsubscribe fstests" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
