On Wed, Jun 30, 2021 at 04:33:10PM +0900, 권오훈 wrote: > Current cleancache api implementation has potential race as follows, > which might lead to corruption in filesystems using cleancache. > > thread 0 thread 1 thread 2 > > in put_page > get pool_id K for fs1 > invalidate_fs on fs1 > frees pool_id K > init_fs for fs2 > allocates pool_id K > put_page puts page > which belongs to fs1 > into cleancache pool for fs2 > > At this point, a file cache which originally belongs to fs1 might be > copied back to cleancache pool of fs2, which might be later used as if > it were normal cleancache of fs2, and could eventually corrupt fs2 when > flushed back. > > Add rwlock in order to synchronize invalidate_fs with other cleancache > operations. > > In normal situations where filesystems are not frequently mounted or > unmounted, there will be little performance impact since > read_lock/read_unlock apis are used. > > Signed-off-by: Ohhoon Kwon <ohoono.kwon@xxxxxxxxxxx> What commit does this fix? Should it go to stable kernels? thanks, greg k-h
