[PATCH v3 1/2] fstests: Add more sanity to seek_sanity_test

Amir Goldstein
2019-04-03T05:59:25Z

seek_sanity_test checks for one of several SEEK_DATA/HOLE
behaviors and allows for the default behavior of filesystems,
where SEEK_HOLE always returns EOF.

This means that if filesystem has a regression in finding
holes, the sanity test won't catch it. And indeed this regression
happened in overlayfs on kernel v4.19 and went unnoticed.

To improve test coverage, add a flag -f to seek_sanity_test to
indicate that the default behavior is not acceptable.
Whitelist all filesystem types that are expected to detect holes
and use wrapper when invoking seek_sanity_test to add the -f flag
to those filesystems.

Overlayfs inherits expected behavior from base fs type.

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

Eryu,

Sorry for the delay.
Changes per your v2 review.

Amir.

Changes from v2:
- Rename helper to _fstyp_has_non_default_seek_data_hole
- Clarify documentation and error message
- Skip new test (seek to punched hole) on default_behavior

common/rc | 47 ++++++++++++++++++++++++++++++++++++++++++
src/seek_sanity_test.c | 14 +++++++++++--
tests/generic/285 | 2 +-
tests/generic/436 | 2 +-
tests/generic/445 | 2 +-
tests/generic/448 | 2 +-
tests/generic/490 | 2 +-
7 files changed, 64 insertions(+), 7 deletions(-)

diff --git a/common/rc b/common/rc
index 1c42515f..7b292321 100644
--- a/common/rc
+++ b/common/rc
@@ -2298,6 +2298,53 @@ _ext4_disable_extent_zeroout()
echo 0 >/sys/fs/ext4/$sdev/extent_max_zeroout_kb
}

+# The default behavior of SEEK_HOLE is to always return EOF.
+# Filesystems that implement non-default behavior return the offset
+# of holes with SEEK_HOLE. There is no way to query the filesystem
+# of which behavior it is implementing.
+# We use this whitelist FSTYP, to set expectation and avoid silent
+# regression of filesystem seek hole behavior.
+#
+# Return 0 for true
+_fstyp_has_non_default_seek_data_hole()
+{
+ if [ -z $1 ]; then
+ local fstyp=$FSTYP
+ else
+ local fstyp=$1
+ fi
+
+ case "$fstyp" in
+ btrfs|ext4|xfs|ceph|cifs|f2fs|gfs2|nfs*|ocfs2|tmpfs)
+ return 0
+ ;;
+ overlay)
+ if [ ! -z $OVL_BASE_FSTYP -a $OVL_BASE_FSTYP != "overlay" ]; then
+ _fstyp_has_non_default_seek_data_hole $OVL_BASE_FSTYP
+ return $?
+ else
+ # Assume that base fs has default behavior
+ return 1
+ fi
+ ;;
+ *)
+ # by default fstyp has default SEEK_HOLE behavior;
+ # if your fs has non-default behavior, add it to whitelist above!
+ return 1
+ ;;
+ esac
+}
+
+# Run seek sanity test with predefined expectation for SEEK_DATA/HOLE behavior
+_run_seek_sanity_test()
+{
+ local testseekargs
+ if _fstyp_has_non_default_seek_data_hole; then
+ testseekargs+="-f"
+ fi
+ $here/src/seek_sanity_test $testseekargs $*
+}
+
# Check if the file system supports seek_data/hole
_require_seek_data_hole()
{
diff --git a/src/seek_sanity_test.c b/src/seek_sanity_test.c
index e9938d1b..a6bda0b1 100644
--- a/src/seek_sanity_test.c
+++ b/src/seek_sanity_test.c
@@ -23,6 +23,7 @@
#endif

static blksize_t alloc_size;
+int allow_default_behavior = 1;
int default_behavior = 0;
int unwritten_extents = 0;
char *base_file_path;
@@ -1119,6 +1120,12 @@ static int test_basic_support(void)
fprintf(stderr, "File system supports the default behavior.\n");
}

+ if (default_behavior && !allow_default_behavior) {
+ fprintf(stderr, "Default behavior is not allowed. Aborting.\n");
+ ret = -1;
+ goto out;
+ }
+
ftruncate(fd, 0);
if (fallocate(fd, 0, 0, alloc_size) == -1) {
if (errno == EOPNOTSUPP)
@@ -1148,7 +1155,7 @@ out:

void usage(char *cmd)
{
- fprintf(stdout, "Usage: %s [-t] [-s <starttest>] [-e <endtest>] base_file_path\n", cmd);
+ fprintf(stdout, "Usage: %s [-tf] [-s <starttest>] [-e <endtest>] base_file_path\n", cmd);
exit(1);
}

@@ -1169,11 +1176,14 @@ int main(int argc, char **argv)
teststart = 1;
testend = 12;

- while ((opt = getopt(argc, argv, "ts:e:")) != -1) {
+ while ((opt = getopt(argc, argv, "tfs:e:")) != -1) {
switch (opt) {
case 't':
check_support++;
break;
+ case 'f':
+ allow_default_behavior = 0;
+ break;
case 's':
teststart = strtol(optarg, NULL, 10);
if (teststart <= 0 || teststart > numtests) {
diff --git a/tests/generic/285 b/tests/generic/285
index b53b3acc..20e89e5b 100755
--- a/tests/generic/285
+++ b/tests/generic/285
@@ -37,7 +37,7 @@ _cleanup()
eval "rm -f $BASE_TEST_FILE.*"
}

-$here/src/seek_sanity_test $BASE_TEST_FILE > $seqres.full 2>&1 ||
+_run_seek_sanity_test $BASE_TEST_FILE > $seqres.full 2>&1 ||
_fail "seek sanity check failed!"

# success, all done
diff --git a/tests/generic/436 b/tests/generic/436
index a3ef70e5..ada60b2e 100755
--- a/tests/generic/436
+++ b/tests/generic/436
@@ -36,7 +36,7 @@ _cleanup()
rm -f $tmp.* $BASE_TEST_FILE.*
}

-$here/src/seek_sanity_test -s 13 -e 16 $BASE_TEST_FILE > $seqres.full 2>&1 ||
+_run_seek_sanity_test -s 13 -e 16 $BASE_TEST_FILE > $seqres.full 2>&1 ||
_fail "seek sanity check failed!"

# success, all done
diff --git a/tests/generic/445 b/tests/generic/445
index 694913ae..248f321b 100755
--- a/tests/generic/445
+++ b/tests/generic/445
@@ -36,7 +36,7 @@ _cleanup()
rm -f $tmp.* $BASE_TEST_FILE.*
}

-$here/src/seek_sanity_test -s 17 -e 17 $BASE_TEST_FILE > $seqres.full 2>&1 ||
+_run_seek_sanity_test -s 17 -e 17 $BASE_TEST_FILE > $seqres.full 2>&1 ||
_fail "seek sanity check failed!"

# success, all done
diff --git a/tests/generic/448 b/tests/generic/448
index d3ec5528..dada499b 100755
--- a/tests/generic/448
+++ b/tests/generic/448
@@ -34,7 +34,7 @@ BASE_TEST_FILE=$TEST_DIR/seek_sanity_testfile_$seq

_require_test_program "seek_sanity_test"

-$here/src/seek_sanity_test -s 18 -e 18 $BASE_TEST_FILE > $seqres.full 2>&1 ||
+_run_seek_sanity_test -s 18 -e 18 $BASE_TEST_FILE > $seqres.full 2>&1 ||
_fail "seek sanity check failed!"

_check_dmesg
diff --git a/tests/generic/490 b/tests/generic/490
index 330c2b60..07b08939 100755
--- a/tests/generic/490
+++ b/tests/generic/490
@@ -39,7 +39,7 @@ _cleanup()
rm -f $base_test_file*
}

-$here/src/seek_sanity_test -s 19 -e 20 $base_test_file > $seqres.full 2>&1 ||
+_run_seek_sanity_test -s 19 -e 20 $base_test_file > $seqres.full 2>&1 ||
_fail "seek sanity check failed!"

# success, all done
--
2.17.1