The fs_info::device_list_mutex and fs_info::scrub_lock creates a
nested locks in btrfs_scrub_dev(). During the lock acquire the
hierarchy is fs_info::device_list_mutex and then fs_info::scrub_lock,
so following the same reverse order during unlock, that is
fs_info::scrub_lock and then fs_info::device_list_mutex.
Signed-off-by: Anand Jain <anand.j...@oracle.com>
---
fs/btrfs/scrub.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 902819d3cf41..b1c2d1cdbd4b 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3865,7 +3865,6 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64
devid, u64 start,
}
sctx->readonly = readonly;
dev->scrub_ctx = sctx;
- mutex_unlock(&fs_info->fs_devices->device_list_mutex);
/*
* checking @scrub_pause_req here, we can avoid
@@ -3875,15 +3874,14 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64
devid, u64 start,
atomic_inc(&fs_info->scrubs_running);
mutex_unlock(&fs_info->scrub_lock);
- if (!is_dev_replace) {
- /*
- * by holding device list mutex, we can
- * kick off writing super in log tree sync.
- */
- mutex_lock(&fs_info->fs_devices->device_list_mutex);
+ /*
+ * by holding device list mutex, we can kick off writing super in log
+ * tree sync.
+ */
+ if (!is_dev_replace)
ret = scrub_supers(sctx, dev);
- mutex_unlock(&fs_info->fs_devices->device_list_mutex);
- }
+
+ mutex_unlock(&fs_info->fs_devices->device_list_mutex);
if (!ret)
ret = scrub_enumerate_chunks(sctx, dev, start, end);
--
1.8.3.1
