Btrfs: fix the race between remove dev and alloc chunk
On remove device path, it updates device->dev_alloc_list but does not hold
chunk lock
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 43c4f09..ee197ec 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1291,7 +1291,9 @@
}
if (device->writeable) {
+ lock_chunks(root);
list_del_init(&device->dev_alloc_list);
+ unlock_chunks(root);
root->fs_info->fs_devices->rw_devices--;
}
@@ -1345,7 +1347,9 @@
}
fs_devices->seed = device->fs_devices->seed;
device->fs_devices->seed = NULL;
+ lock_chunks(root);
__btrfs_close_devices(device->fs_devices);
+ unlock_chunks(root);
free_fs_devices(device->fs_devices);
}
@@ -1377,8 +1381,10 @@
return ret;
error_undo:
if (device->writeable) {
+ lock_chunks(root);
list_add(&device->dev_alloc_list,
&root->fs_info->fs_devices->alloc_list);
+ unlock_chunks(root);
root->fs_info->fs_devices->rw_devices++;
}
goto error_brelse;