From 36bd3298141ab084e6d68f6f54d8eefd80381fb0 Mon Sep 17 00:00:00 2001 From: Anand Jain Date: Fri, 10 Jan 2020 12:26:34 +0800 Subject: [PATCH] btrfs: device stats, log when stats are zeroed [ Upstream commit a69976bc69308aa475d0ba3b8b3efd1d013c0460 ] We had a report indicating that some read errors aren't reported by the device stats in the userland. It is important to have the errors reported in the device stat as user land scripts might depend on it to take the reasonable corrective actions. But to debug these issue we need to be really sure that request to reset the device stat did not come from the userland itself. So log an info message when device error reset happens. For example: BTRFS info (device sdc): device stats zeroed by btrfs(9223) Reported-by: philip@philip-seeger.de Link: https://www.spinics.net/lists/linux-btrfs/msg96528.html Reviewed-by: Josef Bacik Signed-off-by: Anand Jain Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/volumes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 358e930df4ac..6d34842912e8 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -7227,6 +7227,8 @@ int btrfs_get_dev_stats(struct btrfs_fs_info *fs_info, else btrfs_dev_stat_reset(dev, i); } + btrfs_info(fs_info, "device stats zeroed by %s (%d)", + current->comm, task_pid_nr(current)); } else { for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) if (stats->nr_items > i)