btrfs/142: enhance regression test for nocsum dio read's repair

I catch this following error from dmesg when this testcase fails.

[17446.661127] Buffer I/O error on dev sdb1, logical block 64, async page read

We expect to inject disk IO errors on the device when xfs_io reads
the specific file, but other processes may trigger IO error earlier.
So, we can use task-filter to solve this problem.

Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

diff --git a/tests/btrfs/142 b/tests/btrfs/142
index 414af1b22f7c77ebae54085a7edabb18b927ae89..5bd8b728c33bbbf25b26688019bf3e68f6bd83c1 100755 (executable)
--- a/tests/btrfs/142
+++ b/tests/btrfs/142
@@ -75,6 +75,7 @@ start_fail()
 {
        echo 100 > $DEBUGFS_MNT/fail_make_request/probability
        echo 2 > $DEBUGFS_MNT/fail_make_request/times
+       echo 1 > $DEBUGFS_MNT/fail_make_request/task-filter
        echo 0 > $DEBUGFS_MNT/fail_make_request/verbose
        echo 1 > $SYSFS_BDEV/make-it-fail
 }
@@ -83,6 +84,7 @@ stop_fail()
 {
        echo 0 > $DEBUGFS_MNT/fail_make_request/probability
        echo 0 > $DEBUGFS_MNT/fail_make_request/times
+       echo 0 > $DEBUGFS_MNT/fail_make_request/task-filter
        echo 0 > $SYSFS_BDEV/make-it-fail
 }
 
@@ -118,16 +120,17 @@ echo "step 3......repair the bad copy" >>$seqres.full
 # since raid1 consists of two copies, and the bad copy was put on stripe #1
 # while the good copy lies on stripe #0, the bad copy only gets access when the
 # reader's pid % 2 == 1 is true
-while true; do
-       # start_fail only fails the following dio read so the repair is
+start_fail
+while [[ -z ${result} ]]; do
+       # enable task-filter only fails the following dio read so the repair is
        # supposed to work.
-       start_fail
-       $XFS_IO_PROG -d -c "pread -b 128K 0 128K" "$SCRATCH_MNT/foobar" > /dev/null &
-       pid=$!
-       wait
-       stop_fail
-       [ $((pid % 2)) == 1 ] && break
+       result=$(bash -c "
+       if [[ \$((\$\$ % 2)) -eq 1 ]]; then
+               echo 1 > /proc/\$\$/make-it-fail
+               exec $XFS_IO_PROG -d -c \"pread -b 128K 0 128K\" \"$SCRATCH_MNT/foobar\"
+       fi");
 done
+stop_fail
 
 _scratch_unmount