generic/774: turn off lfsr

This test fails mostly-predictably across my testing fleet with:

 --- /run/fstests/bin/tests/generic/774.out	2025-10-20 10:03:43.432910446 -0700
 +++ /var/tmp/fstests/generic/774.out.bad	2025-11-10 01:14:58.941775866 -0800
 @@ -1,2 +1,11 @@
 QA output created by 774
 +fio: failed initializing LFSR
 +verify: bad magic header 0, wanted acca at file /opt/test-file offset 0, length 33554432 (requested block: offset=0, length=33554432)
 +verify: bad magic header 0, wanted acca at file /opt/test-file offset 33554432, length 33554432 (requested block: offset=33554432, length=33554432)
 +verify: bad magic header 0, wanted acca at file /opt/test-file offset 67108864, length 33554432 (requested block: offset=67108864, length=33554432)
 +verify: bad magic header 0, wanted acca at file /opt/test-file offset 100663296, length 33554432 (requested block: offset=100663296, length=33554432)
 +verify: bad magic header 0, wanted acca at file /opt/test-file offset 134217728, length 33554432 (requested block: offset=134217728, length=33554432)
 +verify: bad magic header 0, wanted acca at file /opt/test-file offset 167772160, length 33554432 (requested block: offset=167772160, length=33554432)
 +verify: bad magic header 0, wanted acca at file /opt/test-file offset 201326592, length 33554432 (requested block: offset=201326592, length=33554432)
 +verify: bad magic header 0, wanted acca at file /opt/test-file offset 234881024, length 33554432 (requested block: offset=234881024, length=33554432)
 Silence is golden

I'm not sure why the linear feedback shift register algorithm is
specifically needed for this test.

Cc: fstests@vger.kernel.org # v2025.10.20
Fixes: 9117fb93b41c38 ("generic: Add atomic write test using fio verify on file mixed mappings")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>

diff --git a/tests/generic/774 b/tests/generic/774
index 28886ed5b09ff74d40c6871491ff866964fb98e0..86ab01fbd358741aea874ddb9482decf474e830d 100755 (executable)
--- a/tests/generic/774
+++ b/tests/generic/774
@@ -56,14 +56,12 @@ group_reporting=1
 ioengine=libaio
 rw=randwrite
 io_size=$((filesize/3))
-random_generator=lfsr
 
 # Create unwritten extents
 [prep_unwritten_blocks]
 ioengine=falloc
 rw=randwrite
 io_size=$((filesize/3))
-random_generator=lfsr
 EOF
 
 cat >$fio_aw_config <<EOF
@@ -73,7 +71,6 @@ ioengine=libaio
 rw=randwrite
 direct=1
 atomic=1
-random_generator=lfsr
 group_reporting=1
 
 filename=$testfile
@@ -93,7 +90,6 @@ cat >$fio_verify_config <<EOF
 [verify_job]
 ioengine=libaio
 rw=read
-random_generator=lfsr
 group_reporting=1
 
 filename=$testfile