btrfs-progs: ci: wait for loop devices before mount

Since a few days the CI started to fail randomly when there were loop
devices used in the tests. The mount fails because some device is
reported to be missing:

  $ losetup --show --find
  /dev/loop3
  ...

  $ mkfs ...
  ERROR: device scan failed on '/dev/loop3': No such file or directory
  ...

  $ mount
  mount: /home/runner/work/btrfs-progs/btrfs-progs/tests/mnt: wrong fs
  type, bad option, bad superblock on /dev/loop3, missing codepage or
  helper program, or other error.

  $ dmesg
  ...
  BTRFS error (device loop0): devid 3 uuid 11d9c345-9527-433e-a024-7102659fa0ee is missing
  BTRFS error (device loop0): failed to read the system array: -2
  BTRFS error (device loop0): open_ctree failed

This was reproducible in the "cli" tests, but also happened on a local
machine.

To fix that wait for all loop devices before mount, the command
'btrfs device ready' should block until that. The convenience helper
does that, for any standalone 'mount' used with loop devices this must
be done manually.

Signed-off-by: David Sterba <dsterba@suse.com>

Author: kdave

tests/cli-tests/017-fi-show-missing/test.sh

@@ -20,6 +20,7 @@ run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f -d raid1 "${loopdevs[@]}"
 # Move the device, changing its path, simulating the device being missing
 run_check $SUDO_HELPER mv "$dev2" /dev/loop-non-existent
 
+cond_wait_for_loopdevs
 run_check $SUDO_HELPER mount -o degraded $dev1 $TEST_MNT
 
 if ! run_check_stdout $SUDO_HELPER "$TOP/btrfs" filesystem show "$TEST_MNT" | \

tests/common

@@ -648,6 +648,9 @@ run_check_mount_test_dev()
 		_fail "Invalid \$TEST_MNT: $TEST_MNT"
 	}
 
+	# Wait for loopdevs before mount as this could fail in the CI for some reason
+	cond_wait_for_loopdevs
+
 	run_check $SUDO_HELPER mount -t btrfs $loop_opt "$@" "$TEST_DEV" "$TEST_MNT"
 }
 
@@ -834,6 +837,7 @@ prepare_loopdevs()
 		chmod a+rw "$loopdev_prefix$i"
 		truncate -s0 "$loopdev_prefix$i"
 		truncate -s2g "$loopdev_prefix$i"
+		run_check sync "$loopdev_prefix$i"
 		loopdevs[$i]=`run_check_stdout $SUDO_HELPER losetup --find --show "$loopdev_prefix$i"`
 	done
 }
@@ -851,6 +855,22 @@ cleanup_loopdevs()
 	run_check $SUDO_HELPER losetup --all
 }
 
+# Loop devices may not be ready for mount after mkfs (observed in the CI), wait
+# for them explicitly. Errors are reported but tolerated, the mount could succeed
+# eventually or the whole test will fail anyway.
+wait_for_loopdevs()
+{
+	for dev in ${loopdevs[@]}; do
+		run_mayfail $SUDO_HELPER "$TOP/btrfs" device ready "$dev"
+	done
+}
+
+cond_wait_for_loopdevs() {
+	if [ -n "${loopdevs[1]}" ]; then
+		wait_for_loopdevs
+	fi
+}
+
 init_env()
 {
 	TEST_MNT="${TEST_MNT:-$TEST_TOP/mnt}"

tests/fsck-tests/052-init-csum-tree/test.sh

@@ -21,6 +21,7 @@ run_check $SUDO_HELPER dd if=/dev/urandom of="$TEST_MNT/nodatasum_file" \
 	bs=16k count=1 status=noxfer > /dev/null 2>&1
 
 # Revert to default datasum
+cond_wait_for_loopdevs
 run_check $SUDO_HELPER mount -o remount,datasum "$TEST_MNT"
 
 # Then create an inode with datasum, but all preallocated extents

tests/misc-tests/006-image-on-missing-device/test.sh

@@ -24,6 +24,7 @@ test_run()
 	run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f -d raid1 -m raid1 "$dev1" "$dev2"
 
 	# we need extents to trigger reading from all devices
+	cond_wait_for_loopdevs
 	run_check $SUDO_HELPER mount "$dev1" "$TEST_MNT"
 	run_check $SUDO_HELPER dd if=/dev/zero of="$TEST_MNT/a" bs=1M count=10
 	run_check $SUDO_HELPER dd if=/dev/zero of="$TEST_MNT/b" bs=4k count=1000 conv=sync

tests/misc-tests/021-image-multi-devices/test.sh

@@ -19,6 +19,7 @@ loop3=${loopdevs[3]}
 # Create the test file system.
 
 run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f "$loop1" "$loop2"
+cond_wait_for_loopdevs
 run_check $SUDO_HELPER mount "$loop1" "$TEST_MNT"
 run_check $SUDO_HELPER dd bs=1M count=1 if=/dev/zero of="$TEST_MNT/foobar"
 orig_md5=$(run_check_stdout stat "$TEST_MNT/foobar" | md5sum | cut -d ' ' -f 1)
@@ -38,6 +39,7 @@ run_check $SUDO_HELPER "$TOP/btrfs-image" -r "$IMAGE" "$loop3"
 # Run check to make sure there is nothing wrong for the recovered image
 run_check $SUDO_HELPER "$TOP/btrfs" check "$loop3"
 
+cond_wait_for_loopdevs
 run_check $SUDO_HELPER mount "$loop3" "$TEST_MNT"
 new_md5=$(run_check_stdout stat "$TEST_MNT/foobar" | md5sum | cut -d ' ' -f 1)
 run_check $SUDO_HELPER umount "$TEST_MNT"

tests/misc-tests/030-missing-device-image/test.sh

@@ -32,6 +32,7 @@ test_missing()
 	run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f -d raid1 -m raid1 "$dev1" "$dev2"
 
 	# fill the fs with some data, we could create space cache
+	cond_wait_for_loopdevs
 	run_check $SUDO_HELPER mount "$dev1" "$TEST_MNT"
 	run_check $SUDO_HELPER dd if=/dev/zero of="$TEST_MNT/a" bs=1M count=10
 	run_check $SUDO_HELPER dd if=/dev/zero of="$TEST_MNT/b" bs=4k count=1000 conv=sync

tests/misc-tests/035-receive-common-mount-point-prefix/test.sh

@@ -23,9 +23,11 @@ loop2=$(run_check_stdout $SUDO_HELPER losetup --find --show dev2)
 run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f "$loop1"
 run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f "$loop2"
 
+cond_wait_for_loopdevs
 run_check $SUDO_HELPER mount "$loop1" "$TEST_MNT"
 run_check $SUDO_HELPER mkdir "$TEST_MNT/ddis"
 run_check $SUDO_HELPER mkdir "$TEST_MNT/ddis-not-a-mount"
+cond_wait_for_loopdevs
 run_check $SUDO_HELPER mount "$loop2" "$TEST_MNT/ddis"
 
 echo "some data" | $SUDO_HELPER tee "$TEST_MNT/ddis/file" > /dev/null

tests/misc-tests/046-seed-multi-mount/test.sh

@@ -47,6 +47,7 @@ nextdevice() {
 	run_check $SUDO_HELPER "$TOP/btrfs" device add ${loopdevs[$nextdev]} "$TEST_MNT"
 	# Although seed sprout would make the fs RW, explicitly remount it RW
 	# just in case of future behavior change.
+	cond_wait_for_loopdevs
 	run_check $SUDO_HELPER mount -o remount,rw "$TEST_MNT"
 	# Rewrite the file
 	md5sum=$(run_check_stdout md5sum "$TEST_MNT/file$nextdev" | awk '{print $1}')

tests/mkfs-tests/001-basic-profiles/test.sh

@@ -24,6 +24,7 @@ test_get_info()
 	# device RAID0 as the same.
 	# Thus kernel may create new SINGLE chunks, causing extra warning
 	# when testing single device RAID0.
+	cond_wait_for_loopdevs
 	run_check $SUDO_HELPER mount -o ro "$dev1" "$TEST_MNT"
 	run_check_stdout "$TOP/btrfs" filesystem df "$TEST_MNT" > "$tmp_out"
 	if grep -q "Multiple block group profiles detected" "$tmp_out"; then

tests/mkfs-tests/027-rootdir-inode/test.sh

@@ -25,6 +25,7 @@ check_global_prereq getfattr
 # doesn't support xattr.
 # Instead we go $TEST_TOP/btrfs-progs-mkfs-tests-027.XXXXXX/ instead.
 run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f "$tmp_dev"
+cond_wait_for_loopdevs
 run_check $SUDO_HELPER mount -t btrfs "$tmp_dev" "$TEST_MNT"
 
 run_check $SUDO_HELPER mkdir "$TEST_MNT/source_dir/"
@@ -39,6 +40,7 @@ run_check $SUDO_HELPER setfattr -n user.foobar "$TEST_MNT/source_dir/foobar"
 run_check $SUDO_HELPER "$TOP/mkfs.btrfs" --rootdir "$TEST_MNT/source_dir" -f "$real_dev"
 run_check $SUDO_HELPER umount "$TEST_MNT"
 
+cond_wait_for_loopdevs
 run_check $SUDO_HELPER mount -t btrfs "$real_dev" "$TEST_MNT"
 
 new_mode=$(run_check_stdout $SUDO_HELPER stat "$TEST_MNT/" | grep "Uid:")