Bug 194961

Problem still occurs.

ftp1 ~ # uname -a
Linux ftp1 4.9.16-gentoo-xeon #13 SMP Tue Apr 18 03:15:39 CEST 2017 x86_64 Intel(R) Xeon(R) CPU E3-1265L V2 @ 2.50GHz GenuineIntel GNU/Linux


ftp1 ~ # btrfs --version
btrfs-progs v4.10.2


ftp1 ~ # btrfs device stats --check /DATA
btrfs device stats: unrecognized option '--check'
usage: btrfs device stats [options] <path>|<device>

    Show device IO error statistics

    Show device IO error statistics for all devices of the given filesystem
    identified by PATH or DEVICE. The filesystem must be mounted.

    -c|--check             return non-zero if any stat counter is not zero
    -z|--reset             show current stats and reset values to zero


ftp1 ~ # btrfs device stats -c /DATA
[/dev/sdf1].write_io_errs    0
[/dev/sdf1].read_io_errs     0
[/dev/sdf1].flush_io_errs    0
[/dev/sdf1].corruption_errs  0
[/dev/sdf1].generation_errs  0
[/dev/sdc1].write_io_errs    0
[/dev/sdc1].read_io_errs     0
[/dev/sdc1].flush_io_errs    0
[/dev/sdc1].corruption_errs  0
[/dev/sdc1].generation_errs  0
[/dev/sdi1].write_io_errs    0
[/dev/sdi1].read_io_errs     0
[/dev/sdi1].flush_io_errs    0
[/dev/sdi1].corruption_errs  0
[/dev/sdi1].generation_errs  0
[/dev/sdb1].write_io_errs    0
[/dev/sdb1].read_io_errs     0
[/dev/sdb1].flush_io_errs    0
[/dev/sdb1].corruption_errs  0
[/dev/sdb1].generation_errs  0
[/dev/sdd1].write_io_errs    0
[/dev/sdd1].read_io_errs     0
[/dev/sdd1].flush_io_errs    0
[/dev/sdd1].corruption_errs  0
[/dev/sdd1].generation_errs  0

Thanks for the report. Seems like below 1-line fix, will resolve this issue. Will sent it for review in a day or two. 

diff --git a/cmds-device.c b/cmds-device.c
index 5e016a7..4337eb2 100644
--- a/cmds-device.c
+++ b/cmds-device.c
@@ -400,6 +400,7 @@ static int cmd_device_stats(int argc, char **argv)
        while (1) {
                int c;
                static const struct option long_options[] = {
+                       {"check", no_argument, NULL, 'c'},
                        {"reset", no_argument, NULL, 'z'},
                        {NULL, 0, NULL, 0}
                };

# ./btrfs device stats --check /mntpt
[/dev/sda6].write_io_errs    0
[/dev/sda6].read_io_errs     0
[/dev/sda6].flush_io_errs    0
[/dev/sda6].corruption_errs  0
[/dev/sda6].generation_errs  0
[/dev/sda7].write_io_errs    0
[/dev/sda7].read_io_errs     0
[/dev/sda7].flush_io_errs    0
[/dev/sda7].corruption_errs  0
[/dev/sda7].generation_errs  0

sent a patch, hopefully it will be merged in next version.

Thanks. Patch applied to devel. Will be released in 4.12 at the latest, there might be a minor 4.11.x release (not decided yet).