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@xxxxxxxxx> --- 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