[PATCH 1/3] md/bitmap: don't set max_write_behind if there is no write mostly device
STALE1811d
From: Guoqing Jiang <hidden>
Date: 2021-10-17 13:50:55
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
We shouldn't set it since write behind IO should only happen to write mostly device. Signed-off-by: Guoqing Jiang <redacted> --- 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; + } + 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 */
--
2.31.1