On Mon, Nov 5, 2018 at 6:50 AM Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > When decoding a lower file handle, we first call ovl_check_origin_fh() > with connected=false to get any real lower dentry for overlay inode > cache lookup. > > If the real dentry is a disconnected dir dentry, ovl_check_origin_fh() > is called again with connected=true to get a connected real dentry > and find the lower layer the real dentry belongs to. > > If the first call returned a connected real dentry, we use it to > lookup an overlay connected dentry, but the first ovl_check_origin_fh() > call with connected=false did not check that the found dentry is under > the root of the layer (see ovl_acceptable()), it only checked that > the found dentry super block matches the uuid of the lower file handle. > > In case there are multiple lower layers on the same fs and the found > dentry is not from the top most lower layer, using the layer index > returned from the first ovl_check_origin_fh() is wrong and we end > up failing to decode the file handle. > > Fix this by always calling ovl_check_origin_fh() with connected=true > if we got a directory dentry in the first call. Hi Amir, Does this have a testcase? Thanks, Miklos
