From: Dave Chinner <dchinner@xxxxxxxxxx> 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 <dchinner@xxxxxxxxxx> --- 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 majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html