Miklos, The following series enables recent overlayfs features for the case of lower with no uuid and in particular a nested overlay. Several posts [1] [2] suggest that both squashfs as lower fs and nested overlay are used by OpenWrt users. Turns out it is rather easy to enable xino, index and nfs_export for some common setups. Persistent and consistent inode numbers for lower squashfs were tested with unionmount test: run --ov --squashfs --verify Tests for xino and NFS export with nested overlay are available in my xfstests tree [3]. I did not test NFS export with lower squashfs - leaving that to interesed OpenWrt users. Intereseted party can use my ovl-nested [4] branch for testing. I am not sure how many users need these features for nested overlay, but nested overlay with index is a pre-requisite for multiple overlayfs snapshots support. Note that patch [3/3] is an optimization that is not required for passing the nested exportfs xfstest tests, but could be useful for real lower (under nested) fs with large file handle sizes. Thanks, Amir. [1] https://lkml.org/lkml/2017/12/13/220 [2] https://www.spinics.net/lists/linux-unionfs/msg01682.html [3] https://github.com/amir73il/xfstests/commits/ovl-nested [4] https://github.com/amir73il/linux/commits/ovl-nested Amir Goldstein (3): ovl: relax requirement for non null uuid of lower fs ovl: disable xino for some nested overlay cases ovl: compact nested ovl_fh fs/overlayfs/copy_up.c | 20 +++++++++++++++- fs/overlayfs/export.c | 15 ++++++++++-- fs/overlayfs/namei.c | 34 +++++++++++++++++++-------- fs/overlayfs/overlayfs.h | 16 ++++++++++--- fs/overlayfs/super.c | 50 ++++++++++++++++++++++++++++++++++++---- fs/overlayfs/util.c | 14 ++++++++--- 6 files changed, 126 insertions(+), 23 deletions(-) -- 2.17.1
