5.10-stable review patch. If anyone has any objections, please let me know.
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From: Guoqing Jiang guoqing.jiang@linux.dev
[ Upstream commit 8c13ab115b577bd09097b9d77916732e97e31b7b ]
We shouldn't set it since write behind IO should only happen to write mostly device.
Signed-off-by: Guoqing Jiang guoqing.jiang@linux.dev Signed-off-by: Song Liu songliubraving@fb.com Stable-dep-of: 44abfa6a95df ("md/md-bitmap: hold 'reconfig_mutex' in backlog_store()") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/md-bitmap.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index f843ade442dec..eb8a2d5ba83f4 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -2476,11 +2476,30 @@ 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 */