[PATCH] fstests: add helper to canonicalize devices used to enable persistent disks

[Luis Chamberlain <mcgrof@kernel.org>]

The filesystem configuration file does not allow you to use symlinks to
devices given the existing sanity checks verify that the target end
device matches the source.

Using a symlink is desirable if you want to enable persistent tests
across reboots. For example you may want to use /dev/disk/by-id/nvme-eui.*
so to ensure that the same drives are used even after reboot. This
is very useful if you are testing for example with a virtualized
environment and are using PCIe passthrough with other qemu NVMe drives
with one or many NVMe drives.

To enable support just add a helper to canonicalize devices prior to
running the tests.

This allows one test runner, kdevops, which I just extended with
support to use real NVMe drives. The drives it uses for the filesystem
configuration optionally is with NVMe eui symlinks so to allow
the same drives to be used over reboots.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 check         |  1 +
 common/config | 44 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/check b/check
index 89e7e7bf20df..d063d3f498fd 100755
--- a/check
+++ b/check
@@ -734,6 +734,7 @@ function run_section()
 	fi
 
 	get_next_config $section
+	_canonicalize_devices
 
 	mkdir -p $RESULT_BASE
 	if [ ! -d $RESULT_BASE ]; then
diff --git a/common/config b/common/config
index 936ac225f4b1..f5a3815a0435 100644
--- a/common/config
+++ b/common/config
@@ -655,6 +655,47 @@ _canonicalize_mountpoint()
 	echo "$parent/$base"
 }
 
+# Enables usage of /dev/disk/by-id/ symlinks to persist target devices
+# over reboots
+_canonicalize_devices()
+{
+	if [ ! -z "$TEST_DEV" ] && [ -L $TEST_DEV ]; then
+		TEST_DEV=$(realpath -e $TEST_DEV)
+	fi
+
+	if [ ! -z "$SCRATCH_DEV" ] && [ -L $SCRATCH_DEV ]; then
+		SCRATCH_DEV=$(realpath -e $SCRATCH_DEV)
+	fi
+
+	if [ ! -z "$TEST_LOGDEV" ] && [ -L $TEST_LOGDEV ]; then
+		TEST_LOGDEV=$(realpath -e $TEST_LOGDEV)
+	fi
+
+	if [ ! -z "$TEST_RTDEV" ] && [ -L $TEST_RTDEV ]; then
+		TEST_RTDEV=$(realpath -e $TEST_RTDEV)
+	fi
+
+	if [ ! -z "$SCRATCH_RTDEV" ] && [ -L $SCRATCH_RTDEV ]; then
+		SCRATCH_RTDEV=$(realpath -e $SCRATCH_RTDEV)
+	fi
+
+	if [ ! -z "$LOGWRITES_DEV" ] && [ -L $LOGWRITES_DEV ]; then
+		LOGWRITES_DEV=$(realpath -e $LOGWRITES_DEV)
+	fi
+
+	if [ ! -z "$SCRATCH_DEV_POOL" ]; then
+		NEW_SCRATCH_POOL=""
+		for i in $SCRATCH_DEV_POOL; do
+			if [ -L $i ]; then
+				NEW_SCRATCH_POOL="$NEW_SCRATCH_POOL $(realpath -e $i)"
+			else
+				NEW_SCRATCH_POOL="$NEW_SCRATCH_POOL $i)"
+			fi
+		done
+		SCRATCH_DEV_POOL="$NEW_SCRATCH_POOL"
+	fi
+}
+
 # On check -overlay, for the non multi section config case, this
 # function is called on every test, before init_rc().
 # When SCRATCH/TEST_* vars are defined in config file, config file
@@ -785,7 +826,6 @@ get_next_config() {
 	fi
 
 	parse_config_section $1
-
 	if [ ! -z "$OLD_FSTYP" ] && [ $OLD_FSTYP != $FSTYP ]; then
 		[ -z "$MOUNT_OPTIONS" ] && _mount_opts
 		[ -z "$TEST_FS_MOUNT_OPTS" ] && _test_mount_opts
@@ -901,5 +941,7 @@ else
 	fi
 fi
 
+_canonicalize_devices
+
 # make sure this script returns success
 /bin/true
-- 
2.39.2