5.4-stable review patch. If anyone has any objections, please let me know.
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From: Yu Kuai yukuai3@huawei.com
[ Upstream commit 44abfa6a95df425c0660d56043020b67e6d93ab8 ]
Several reasons why 'reconfig_mutex' should be held:
1) rdev_for_each() is not safe to be called without the lock, because rdev can be removed concurrently. 2) mddev_destroy_serial_pool() and mddev_create_serial_pool() should not be called concurrently. 3) mddev_suspend() from mddev_destroy/create_serial_pool() should be protected by the lock.
Fixes: 10c92fca636e ("md-bitmap: create and destroy wb_info_pool with the change of backlog") Signed-off-by: Yu Kuai yukuai3@huawei.com Link: https://lore.kernel.org/r/20230706083727.608914-3-yukuai1@huaweicloud.com Signed-off-by: Song Liu song@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/md-bitmap.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index a549662ff4e51..843139447a964 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -2488,6 +2488,10 @@ backlog_store(struct mddev *mddev, const char *buf, size_t len) if (backlog > COUNTER_MAX) return -EINVAL;
+ rv = mddev_lock(mddev); + if (rv) + return rv; + /* * Without write mostly device, it doesn't make sense to set * backlog for max_write_behind. @@ -2501,6 +2505,7 @@ backlog_store(struct mddev *mddev, const char *buf, size_t len) if (!has_write_mostly) { pr_warn_ratelimited("%s: can't set backlog, no write mostly device available\n", mdname(mddev)); + mddev_unlock(mddev); return -EINVAL; }
@@ -2518,6 +2523,8 @@ backlog_store(struct mddev *mddev, const char *buf, size_t len) } if (old_mwb != backlog) md_bitmap_update_sb(mddev->bitmap); + + mddev_unlock(mddev); return len; }