On 2023/6/27 01:32, Zorro Lang wrote:
On Mon, Jun 26, 2023 at 02:00:52PM +0800, Qu Wenruo wrote:
[BUG]
After commit ab41f0bddb73 ("common/btrfs: use _scratch_cycle_mount to
ensure all page caches are dropped"), the test case btrfs/143 can fail
like below:
btrfs/143 6s ... [failed, exit status 1]- output mismatch (see ~/xfstests/results//btrfs/143.out.bad)
--- tests/btrfs/143.out 2020-06-10 19:29:03.818519162 +0100
+++ ~/xfstests/results//btrfs/143.out.bad 2023-06-19 17:04:00.575033899 +0100
@@ -1,37 +1,6 @@
QA output created by 143
wrote 131072/131072 bytes
XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
................
-XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
................
-XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
................
-XXXXXXXX: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
................
[CAUSE]
Test case btrfs/143 uses dm-dust device to emulate read errors, this
means we can not use _scratch_cycle_mount to cycle mount $SCRATCH_MNT.
As it would go mount $SCRATCH_DEV, not the dm-dust device to
$SCRATCH_MNT.
This prevents us to trigger read-repair (since no error would be hit)
thus fail the test.
[FIX]
Since we can mount whatever device at $SCRATCH_MNT, we can not use
_scratch_cycle_mount in this case.
Instead implement a small helper to grab the mounted device and its
mount options, and use the same device and mount options to cycle
$SCRATCH_MNT mount.
This would fix btrfs/143 and hopefully future test cases which use dm
devices.
Reported-by: Filipe Manana <fdmanana@xxxxxxxx>
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
common/btrfs | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/common/btrfs b/common/btrfs
index 175b33ae..4a02b2cc 100644
--- a/common/btrfs
+++ b/common/btrfs
@@ -601,8 +601,18 @@ _btrfs_buffered_read_on_mirror()
# The drop_caches doesn't seem to drop every pages on aarch64 with
# 64K page size.
# So here as another workaround, cycle mount the SCRATCH_MNT to ensure
- # the cache are dropped.
- _scratch_cycle_mount
+ # the cache are dropped, but we can not use _scratch_cycle_mount, as
+ # we may mount whatever dm device at SCRATCH_MNT.
+ # So here we grab the mounted block device and its mount options, then
+ # unmount and re-mount with the same device and options.
+ local mount_info=$(_mount | grep "$SCRATCH_MNT")
+ if [ -z "$mount_info" ]; then
+ _fail "failed to grab mount info of $SCRATCH_MNT"
+ fi
+ local dev=$(echo $mount_info | $AWK_PROG '{print $1}')
+ local opts=$(echo $mount_info | $AWK_PROG '{print $6}' | sed 's/[()]//g')
The `findmnt` can help to get $dev and $opts:
local dev=$(findmnt -n -T $SCRATCH_MNT -o SOURCE)
local opts=$(findmnt -n -T $SCRATCH_MNT -o OPTIONS)
If you hope to check you can keep:
if [ -z "$dev" -o -z "$opts" ];then
_fail "failed to grab mount info of $SCRATCH_MNT"
fi
That's really helpful!
+ _scratch_unmount
+ _mount $dev -o $opts $SCRATCH_MNT
I'm wondering can this help that, after you get the "real" device name:
SCRATCH_DEV=$dev _scratch_cycle_mount
AFAIK we still need to specify the mount option.
As it's possible previous mount is specifying certain mount option
that's not in MOUNT_OPTIONS environment variables.
E.g. mounting a specific subvolume or a temporary mount option.
Thus I believe we may still need to specific the mount options.
Thanks,
Qu
Thanks,
Zorro
while [[ -z $( (( BASHPID % nr_mirrors == mirror )) &&
exec $XFS_IO_PROG \
-c "pread -b $size $offset $size" $file) ]]; do
--
2.39.0
