Re: [PATCH] fstests: btrfs: enhance regression test for nocsum dio read's repair

[Lu Fengqi]

On Tue, Aug 15, 2017 at 05:16:06PM +0800, Eryu Guan wrote:
>On Mon, Aug 14, 2017 at 03:03:13PM +0800, Lu Fengqi wrote:
>> 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 
>
>This looks OK to me. Does btrfs/143 need a similar fix?
>
>Thanks,
>Eryu
>
>

Although btrfs/143 has a similar problem, this method doesn't work for it.
Unlike btrfs/142, the second IO error needs to be triggered by another process,
not by xfs_io. So we can't simply set task-filter to solve this problem.

I'm still investigating a way to solve the problem.

Do you have any ideas?
Any help will be greatly appreciated.

-- 
Thanks,
Lu


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Re: [PATCH] fstests: btrfs: enhance regression test for nocsum dio read's repair

[Eryu Guan]

On Mon, Aug 14, 2017 at 03:03:13PM +0800, Lu Fengqi wrote:
> 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 

This looks OK to me. Does btrfs/143 need a similar fix?

Thanks,
Eryu
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[PATCH] fstests: btrfs: enhance regression test for nocsum dio read's repair

[Lu Fengqi]

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 
---
 tests/btrfs/142 | 19 +++
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/tests/btrfs/142 b/tests/btrfs/142
index 414af1b2..5bd8b728 100755
--- 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
 
-- 
2.14.1



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