[PATCH -next 2/2] md/md-bitmap: hold 'reconfig_mutex' in backlog_store()
From: Yu Kuai <hidden>
Date: 2023-07-06 08:39:05
Also in:
lkml
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
From: Yu Kuai <redacted>
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 <redacted>
---
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 1f3339961159..6f9ff14971f9 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c@@ -2546,6 +2546,10 @@ 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.
@@ -2559,6 +2563,7 @@ 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; }
@@ -2574,6 +2579,8 @@ 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; }
--
2.39.2