On Wed, Jan 25, 2017 at 08:51:24AM +0200, Amir Goldstein wrote:
> Instead of setting the fake TEST/SCRATCH_DEV vars to existing overlay
> directories, allow setting the vars OVERLAY_BASE_DEV/MNT, to configure
> the base fs where overlay directories are created. For example:
>
> -export TEST_DEV=/mnt/xfs/ovl/test
> -export SCRATCH_DEV=/mnt/xfs/ovl/scratch
> +export OVERLAY_BASE_DEV=/dev/mapper/test-xfs
> +export OVERLAY_BASE_MNT=/mnt/xfs
> export TEST_DIR=/mnt/test
> export SCRATCH_MNT=/mnt/scratch
> export FSTYP=overlay
>
> With this change, the base fs is mounted before running the tests
> unmounted after running the tests and recycled on _test_cycle_mount.
> This helps catching overlayfs bugs related to leaking objects in
> underlying (base) fs.
This looks useful to me, actually overlay/005 is one test that is
testing a memleak bug, but it uses loop device as a underlying fs and
umount the loop dev to trigger memleak bug.
But having two methods to config overlayfs testing worries me a bit, it
can be confusing to users. At least we should document them well.
Perhaps eventually we can kill the old way?
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> common/config | 35 ++++++++++++++++++++++++++++++++++-
> common/rc | 8 ++++++++
> 2 files changed, 42 insertions(+), 1 deletion(-)
>
> Eryu,
>
> I was planning to also support _test_mkfs for base fs (as kvm-xfstests does),
> but decided to make a RFC rest stop after _test_mount, which seems useful in
> its own right.
I'm not sure about this. One down side of doing this is it introduces
the complexity of handling FSTYP and MKFS_OPTIONS of underlying fs,
which seems way too complex at this point. I think a user pre-mkfs'ed
device would be sufficient?
>
> The main point to consider is whether it is worth separating OVERLAY_BASE_DEV
> to test and scratch base devices. This patch (with shared dev) is much simpler
> to configure to I am sending it out to see if folk think it is sufficiently
> useful as is.
I'd prefer separating test and scratch devices, so we have a fine
control on them in tests. One problem with this shared dev is it's
possible for either _overlay_test_unmount or _overlay_scratch_unmount to
unmount the underlying fs, while the other overlay is still mounted.
That's a strange behavior, I expected umount the base dev return EBUSY
in this case, but it doesn't (but a subsequent mkfs does return EBUSY,
so the device is not really usable). I reported this bug in RH bugzilla
(a private bug) and it was closed as WONTFIX.
Thanks,
Eryu
>
> The limitation of keepong this patch as is, is not being able to recycle base fs
> on _scratch_mount/umount/recycle and not being able to mkfs base fs on _scratch_mkfs.
>
> Thought?
>
> Amir.
>
> diff --git a/common/config b/common/config
> index 0706aca..d63c22a 100644
> --- a/common/config
> +++ b/common/config
> @@ -35,6 +35,8 @@
> # RMT_TAPE_DEV - the remote tape device for the xfsdump tests
> # RMT_IRIXTAPE_DEV- the IRIX remote tape device for the xfsdump tests
> # RMT_TAPE_USER - remote user for tape device
> +# OVERLAY_BASE_DEV- device for base fs containing overlay directories
> +# OVERLAY_BASE_MNT- mount point for base fs of overlay directories
> #
> # - These can be added to $HOST_CONFIG_DIR (witch default to ./config)
> # below or a separate local configuration file can be used (using
> @@ -77,6 +79,9 @@ export XFS_MKFS_OPTIONS=${XFS_MKFS_OPTIONS:=-bsize=4096}
> export TIME_FACTOR=${TIME_FACTOR:=1}
> export LOAD_FACTOR=${LOAD_FACTOR:=1}
> export DEBUGFS_MNT=${DEBUGFS_MNT:="/sys/kernel/debug"}
> +# directory inside $OVERLAY_BASE_MNT where TEST/SCRATCH_DEV dirs are created
> +export OVERLAY_BASE_DIR=${OVERLAY_BASE_DIR:="ovl"}
> +# directories created inside TEST/SCRATCH_DEV
> export OVERLAY_UPPER_DIR=${OVERLAY_UPPER_DIR:="upper"}
> export OVERLAY_LOWER_DIR=${OVERLAY_LOWER_DIR:="lower"}
> export OVERLAY_WORK_DIR=${OVERLAY_WORK_DIR:="work"}
> @@ -443,7 +448,7 @@ _check_device()
> echo $dev | grep -qE ":|//" > /dev/null 2>&1
> network_dev=$?
> if [ "$FSTYP" == "overlay" ]; then
> - if [ ! -d "$dev" ]; then
> + if [ -z "$OVERLAY_BASE_MNT" -a ! -d "$dev" ]; then
> _fatal "common/config: $name ($dev) is not a directory for overlay"
> fi
> elif [ ! -b "$dev" -a "$network_dev" != "0" ]; then
> @@ -451,6 +456,29 @@ _check_device()
> fi
> }
>
> +# Derive TEST/SCRATCH_DEV from base fs if OVERLAY_BASE_MNT is defined
> +_config_overlay()
> +{
> + # There are 2 options for testing overlayfs:
> + #
> + # 1. (legacy) set SCRATCH/TEST_DEV to existing directories
> + # on an already mounted fs.
> + #
> + # 2. set OVERLAY_BASE_DEV/MNT to configure base fs.
> + # SCRATCH/TEST_DEV are derived from OVERLAY_BASE_MNT and therein,
> + # overlay fs directories will be created.
> + [ -n "$OVERLAY_BASE_MNT" ] || return
> +
> + _check_device OVERLAY_BASE_DEV required $OVERLAY_BASE_DEV
> + if [ ! -d "$OVERLAY_BASE_MNT" ]; then
> + echo "common/config: Error: \$OVERLAY_BASE_MNT ($OVERLAY_BASE_MNT) is not a directory"
> + exit 1
> + fi
> +
> + export TEST_DEV="$OVERLAY_BASE_MNT/$OVERLAY_BASE_DIR/test"
> + export SCRATCH_DEV="$OVERLAY_BASE_MNT/$OVERLAY_BASE_DIR/scratch"
> +}
> +
> # Parse config section options. This function will parse all the configuration
> # within a single section which name is passed as an argument. For section
> # name format see comments in get_config_sections().
> @@ -525,6 +553,11 @@ get_next_config() {
> export RESULT_BASE="$here/results/"
> fi
>
> + # Maybe derive TEST_DEV from OVERLAY_BASE_MNT
> + if [ "$FSTYP" == "overlay" ]; then
> + _config_overlay
> + fi
> +
> # Mandatory Config values.
> MC=""
> [ -z "$EMAIL" ] && MC="$MC EMAIL"
> diff --git a/common/rc b/common/rc
> index 862bc04..8c403e3 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -322,6 +322,11 @@ _overlay_mount()
>
> _overlay_test_mount()
> {
> + if [ -n "$OVERLAY_BASE_MNT" ]; then
> + _mount $OVERLAY_BASE_MOUNT_OPTIONS \
> + $SELINUX_MOUNT_OPTIONS \
> + $OVERLAY_BASE_DEV $OVERLAY_BASE_MNT
> + fi
> _overlay_mount $TEST_DEV $TEST_DIR $*
> }
>
> @@ -333,6 +338,9 @@ _overlay_scratch_mount()
> _overlay_test_unmount()
> {
> $UMOUNT_PROG $TEST_DIR
> + if [ -n "$OVERLAY_BASE_MNT" ]; then
> + $UMOUNT_PROG $OVERLAY_BASE_MNT
> + fi
> }
>
> _overlay_scratch_unmount()
> --
> 2.7.4
>
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