On Sun, Oct 17, 2021 at 6:50 AM Guoqing Jiang <guoqing.jiang@xxxxxxxxx> wrote:
>
> We shouldn't set it since write behind IO should only happen to write
> mostly device.
>
> Signed-off-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxx>
Applied to md-next with a couple minor changes.
> ---
> drivers/md/md-bitmap.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
> index e29c6298ef5c..9424879d8d7e 100644
> --- a/drivers/md/md-bitmap.c
> +++ b/drivers/md/md-bitmap.c
> @@ -2469,11 +2469,29 @@ backlog_store(struct mddev *mddev, const char *buf, size_t len)
> {
> unsigned long backlog;
> unsigned long old_mwb = mddev->bitmap_info.max_write_behind;
> + struct md_rdev *rdev;
> + bool has_write_mostly = false;
> int rv = kstrtoul(buf, 10, &backlog);
> if (rv)
> return rv;
> if (backlog > COUNTER_MAX)
> return -EINVAL;
> +
> + /*
> + * Without write mostly device, it doesn't make sense to set
> + * backlog for max_write_behind.
> + */
> + rdev_for_each(rdev, mddev)
> + if (test_bit(WriteMostly, &rdev->flags)) {
> + has_write_mostly = true;
> + break;
> + }
Added curly brackets for multi-line block.
> + if (!has_write_mostly) {
> + pr_warn_ratelimited("%s: can't set backlog, no write mostly"
> + " device available\n", mdname(mddev));
Merged the two strings to a single line. checkpatch.pl should complain
about splitting a print string.
> + return -EINVAL;
> + }
> +
> mddev->bitmap_info.max_write_behind = backlog;
> if (!backlog && mddev->serial_info_pool) {
> /* serial_info_pool is not needed if backlog is zero */
> --
> 2.31.1
>
