When norandommap is enabled, fio logs the I/O entries in a RB tree. This
is to account for offset overlaps and overwrites. Then during verify
phase, the I/O entries are picked from the top and in this case the
smallest offset is verified first and so on. This creates a mismatch
during the header verification as the seed generated at the time of read
differs from what was logged during write. Skip seed verification in
this scenario.
fixes #1756
Signed-off-by: Ankit Kumar <ankit.kumar@xxxxxxxxxxx>
---
HOWTO.rst | 12 +++++++-----
fio.1 | 3 ++-
init.c | 6 +++---
3 files changed, 12 insertions(+), 9 deletions(-)
diff --git a/HOWTO.rst b/HOWTO.rst
index 6d462af3..fa6b44a5 100644
--- a/HOWTO.rst
+++ b/HOWTO.rst
@@ -1564,11 +1564,13 @@ I/O type
this option is given, fio will just get a new random offset without looking
at past I/O history. This means that some blocks may not be read or written,
and that some blocks may be read/written more than once. If this option is
- used with :option:`verify` and multiple blocksizes (via :option:`bsrange`),
- only intact blocks are verified, i.e., partially-overwritten blocks are
- ignored. With an async I/O engine and an I/O depth > 1, it is possible for
- the same block to be overwritten, which can cause verification errors. Either
- do not use norandommap in this case, or also use the lfsr random generator.
+ used with :option:`verify` then :option:`verify_header_seed` will be
+ disabled. If this option is used with :option:`verify` and multiple blocksizes
+ (via :option:`bsrange`), only intact blocks are verified, i.e.,
+ partially-overwritten blocks are ignored. With an async I/O engine and an I/O
+ depth > 1, it is possible for the same block to be overwritten, which can
+ cause verification errors. Either do not use norandommap in this case, or also
+ use the lfsr random generator.
.. option:: softrandommap=bool
diff --git a/fio.1 b/fio.1
index 3fbc1657..07f09f07 100644
--- a/fio.1
+++ b/fio.1
@@ -1368,7 +1368,8 @@ Normally fio will cover every block of the file when doing random I/O. If
this option is given, fio will just get a new random offset without looking
at past I/O history. This means that some blocks may not be read or written,
and that some blocks may be read/written more than once. If this option is
-used with \fBverify\fR and multiple blocksizes (via \fBbsrange\fR),
+used with \fBverify\fR then \fBverify_header_seed\fR will be disabled. If this
+option is used with \fBverify\fR and multiple blocksizes (via \fBbsrange\fR),
only intact blocks are verified, i.e., partially-overwritten blocks are
ignored. With an async I/O engine and an I/O depth > 1, it is possible for
the same block to be overwritten, which can cause verification errors. Either
diff --git a/init.c b/init.c
index 3d6230cb..91f056e3 100644
--- a/init.c
+++ b/init.c
@@ -863,12 +863,12 @@ static int fixup_options(struct thread_data *td)
}
/*
- * Disable rand_seed check when we have verify_backlog, or
- * zone reset frequency for zonemode=zbd.
+ * Disable rand_seed check when we have verify_backlog,
+ * zone reset frequency for zonemode=zbd, or norandommap.
* Unless we were explicitly asked to enable it.
*/
if (!td_write(td) || (td->flags & TD_F_VER_BACKLOG) ||
- o->zrf.u.f) {
+ o->zrf.u.f || o->norandommap) {
if (!fio_option_is_set(o, verify_header_seed))
o->verify_header_seed = 0;
}
--
2.25.1
