Commit 8c13ab11 authored by Guoqing Jiang's avatar Guoqing Jiang Committed by Song Liu
Browse files

md/bitmap: don't set max_write_behind if there is no write mostly device 



We shouldn't set it since write behind IO should only happen to write
mostly device.

Signed-off-by: default avatarGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
parent e2daec48

drivers/md/md-bitmap.c

+19 −0
Original line number Diff line number Diff line
@@ -2469,11 +2469,30 @@ 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;

		}

	}

	if (!has_write_mostly) {

		pr_warn_ratelimited("%s: can't set backlog, no write mostly device available\n",

				    mdname(mddev));

		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 */