From 492afae5524be53a7639be19bad40c0bade2b7b6 Mon Sep 17 00:00:00 2001
From: Benjamin LaHaise <bcrl@kvack.org>
Date: Wed, 20 May 2020 16:22:51 -0400
Subject: [PATCH] scoutfs: add data_wait_err for reporting errors

Add support for reporting errors to data waiters via a new
SCOUTFS_IOC_DATA_WAIT_ERR ioctl.  This allows waiters to return an error
to readers when staging fails.

Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
[zab: renamed to data_wait_err, took ino arg]
Signed-off-by: Zach Brown <zab@versity.com>
---
 tests/golden/offline-extent-waiting   | 14 ++++++++++++++
 tests/tests/offline-extent-waiting.sh | 24 ++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/tests/golden/offline-extent-waiting b/tests/golden/offline-extent-waiting
index ed09574f..5b163cc9 100644
--- a/tests/golden/offline-extent-waiting
+++ b/tests/golden/offline-extent-waiting
@@ -14,6 +14,20 @@ offline wating should be empty again:
 offline waiting should now have one known entry:
 offline waiting should be empty again:
 0
+== EIO injection for waiting readers works
+offline waiting should now have two known entries:
+2
+data_wait_err found 2 waiters.
+offline waiting should now have 0 known entries:
+0
+dd: error reading ‘/mnt/test/test/offline-extent-waiting/dir/file’: Input/output error
+0+0 records in
+0+0 records out
+dd: error reading ‘/mnt/test/test/offline-extent-waiting/dir/file’: Input/output error
+0+0 records in
+0+0 records out
+offline waiting should be empty again:
+0
 == readahead while offline does no harm
 == waiting on interesting blocks works
 offline waiting is empty at block 0
diff --git a/tests/tests/offline-extent-waiting.sh b/tests/tests/offline-extent-waiting.sh
index d9f95245..fb413562 100644
--- a/tests/tests/offline-extent-waiting.sh
+++ b/tests/tests/offline-extent-waiting.sh
@@ -76,6 +76,30 @@ wait "$pid" 2> /dev/null
 echo "offline waiting should be empty again:"
 scoutfs data-waiting 0 0 "$DIR" | wc -l
 
+echo "== EIO injection for waiting readers works"
+ino=$(stat -c "%i" "$DIR/file")
+dd if="$DIR/file" bs=$BS skip=0 of=/dev/null 2>&1 | \
+	t_filter_fs | head -3 > $T_TMP.cat1 &
+pid="$!"
+dd if="$DIR/file" bs=$BS skip=1 of=/dev/null 2>&1 | \
+	t_filter_fs | head -3 > $T_TMP.cat2 &
+pid2="$!"
+sleep .1
+echo "offline waiting should now have two known entries:"
+scoutfs data-waiting 0 0 "$DIR" | wc -l
+expect_wait "$DIR/file" "read" $ino 0 $ino 1
+scoutfs data-wait-err "$DIR" "$ino" "$vers" 0 $((BS*2)) read -5
+sleep .1
+echo "offline waiting should now have 0 known entries:"
+scoutfs data-waiting 0 0 "$DIR" | wc -l
+# silence terminated message
+wait "$pid" 2> /dev/null
+wait "$pid2" 2> /dev/null
+cat $T_TMP.cat1
+cat $T_TMP.cat2
+echo "offline waiting should be empty again:"
+scoutfs data-waiting 0 0 "$DIR" | wc -l
+
 echo "== readahead while offline does no harm"
 xfs_io -c "fadvise -w 0 $BYTES" "$DIR/file"
 scoutfs stage "$DIR/file" "$vers" 0 $BYTES "$DIR/golden"