Btrfs: stop all workers before cleaning up roots
Dave reported a panic because the extent_root->commit_root was NULL in the
caching kthread. That is because we just unset it in free_root_pointers, which
is not the correct thing to do, we have to either wait for the caching kthread
to complete or hold the extent_commit_sem lock so we know the thread has exited.
This patch makes the kthreads all stop first and then we do our cleanup. This
should fix the race. Thanks,
Reported-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7c66c23..b8b60b6 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3514,13 +3514,13 @@
btrfs_free_block_groups(fs_info);
- free_root_pointers(fs_info, 1);
+ btrfs_stop_all_workers(fs_info);
del_fs_roots(fs_info);
- iput(fs_info->btree_inode);
+ free_root_pointers(fs_info, 1);
- btrfs_stop_all_workers(fs_info);
+ iput(fs_info->btree_inode);
#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
if (btrfs_test_opt(root, CHECK_INTEGRITY))