[PATCH] fstests: reduce runtime of check -n

[Amir Goldstein <amir73il@gmail.com>]

kvm-xfstests invokes check -n twice to pre-process and generate the
tests-to-run list, which is then being passed as a long list of tests
for invkoing check in the command line.

check invokes dirname, basename and sed several times per test just
for doing basic string prefix/suffix trimming.
Use bash string pattern matching instead which is much faster.

Note that the following pattern matching expression change:
< test_dir=${test_dir#$SRC_DIR/*}
> t=${t#$SRC_DIR/}
does not change the meaning of the expression, because the
shortest match of "$SRC_DIR/*" that is being trimmed is "$SRC_DIR/"
and removing the tests/ prefix is what this code intended to do.

With check -n, there is no need to cleanup the results dir,
but check -n is doing that for every single listed test.
Move the cleanup of results dir to before actually running the test.

These improvements to check pre-test code cut down several minutes
from the time until tests actually start to run with kvm-xfstests.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---

Zorro,

Just to clarify, this change is not expected to change behavior -
only to improve runtime of check -n and the things that happen
before the first test is invoked.

Thanks,
Amir.

 check | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/check b/check
index e36978c1..1a16eccb 100755
--- a/check
+++ b/check
@@ -399,9 +399,9 @@ if $have_test_arg; then
 		*)	# Expand test pattern (e.g. xfs/???, *fs/001)
 			list=$(cd $SRC_DIR; echo $1)
 			for t in $list; do
-				test_dir=`dirname $t`
-				test_dir=${test_dir#$SRC_DIR/*}
-				test_name=`basename $t`
+				t=${t#$SRC_DIR/}
+				test_dir=${t%/*}
+				test_name=${t#*/}
 				group_file=$SRC_DIR/$test_dir/group.list
 
 				if grep -Eq "^$test_name" $group_file; then
@@ -849,18 +849,14 @@ function run_section()
 
 		# the filename for the test and the name output are different.
 		# we don't include the tests/ directory in the name output.
-		export seqnum=`echo $seq | sed -e "s;$SRC_DIR/;;"`
-
-		# Similarly, the result directory needs to replace the tests/
-		# part of the test location.
-		group=`dirname $seq`
+		export seqnum=${seq#$SRC_DIR/}
+		group=${seqnum%/*}
 		if $OPTIONS_HAVE_SECTIONS; then
-			export RESULT_DIR=`echo $group | sed -e "s;$SRC_DIR;${RESULT_BASE}/$section;"`
 			REPORT_DIR="$RESULT_BASE/$section"
 		else
-			export RESULT_DIR=`echo $group | sed -e "s;$SRC_DIR;$RESULT_BASE;"`
 			REPORT_DIR="$RESULT_BASE"
 		fi
+		export RESULT_DIR="$REPORT_DIR/$group"
 		seqres="$REPORT_DIR/$seqnum"
 
 		# Generate the entire section report with whatever test results
@@ -872,9 +868,6 @@ function run_section()
 					     "" &> /dev/null
 		fi
 
-		mkdir -p $RESULT_DIR
-		rm -f ${RESULT_DIR}/require_scratch*
-		rm -f ${RESULT_DIR}/require_test*
 		echo -n "$seqnum"
 
 		if $showme; then
@@ -899,6 +892,9 @@ function run_section()
 		fi
 
 		# really going to try and run this one
+		mkdir -p $RESULT_DIR
+		rm -f ${RESULT_DIR}/require_scratch*
+		rm -f ${RESULT_DIR}/require_test*
 		rm -f $seqres.out.bad $seqres.hints
 
 		# check if we really should run it
-- 
2.34.1