On Wed, Jul 04, 2018 at 04:18:09PM +0800, Anand Jain wrote: > > > On 06/21/2018 01:51 AM, David Sterba wrote: > > The stale device list removal needs to be protected by device_list_mutex > > too as this could delete from the list and could race with another list > > modification and cause crash. > > > > The device needs to be fully initialized before it's added to the list > > so the fs_devices also need to be set under the mutex. > > > > Signed-off-by: David Sterba <dsterba@xxxxxxxx> > > --- > > fs/btrfs/volumes.c | 5 ++--- > > 1 file changed, 2 insertions(+), 3 deletions(-) > > > > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > > index 1da162928d1a..02246f9af0a3 100644 > > --- a/fs/btrfs/volumes.c > > +++ b/fs/btrfs/volumes.c > > @@ -791,12 +791,11 @@ static noinline struct btrfs_device *device_list_add(const char *path, > > rcu_assign_pointer(device->name, name); > > > > mutex_lock(&fs_devices->device_list_mutex); > > + device->fs_devices = fs_devices; > > list_add_rcu(&device->dev_list, &fs_devices->devices); > > fs_devices->num_devices++; > > - mutex_unlock(&fs_devices->device_list_mutex); > > - > > - device->fs_devices = fs_devices; > > btrfs_free_stale_devices(path, device); > > > This is not correct. > > btrfs_free_stale_devices need the per fs_devices local device_list_mutex > lock as it traverses through the fs_uuids list. Holding just the lock of > the %fs_devices which is being scanned or mounted is not correct. I see, ok. The use of fs_devs is not very visible in btrfs_free_stale_devices but at least the function comment hints that all devices are being traversed. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
