On Thu, Jul 13, 2023 at 3:03 PM Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > Miklos, > > This is the second part of the work to support fanotify reporting of > events with file ids on overlayfs. The fanotify_event_info_fid struct > reported with fanotify events has an object file handle and an fsid, > so fanotify requires that filesystems can encode file handles and have > a non-zero f_fsid. > > The first part [1] that was merged to v6.5-rc1, relaxed the fanotify > requirements for filesystems to support reporting events with fid to > require only the ->encode_fh() export operation. > > Patch 1 changes overlayfs export_operations to meet the new requirements > with the default overlay configurations (i.e. no need for nfs_export=on), > thus, allowing an fanotify watch with FAN_REPORT_FID on overlayfs. > There are LTS tests [2] for fanotify(FAN_REPORT_FID) + overlayfs. > > Patches 2-4 are not strcitly needed to support reporting fanotify events > with fid, because overlayfs already reports a non-zero f_fsid, it's just > not a unique fsid. So before allowing to report events with overlayfs > fids, I wanted to fix overlayfs fsid to be more unique. > > I wanted to implement a persistent and unique fsid for overlayfs. > I wanted it to be the default behavior, but needed to avoid breaking > applications that rely on an existing overlayfs fsid to persist. > I came up with a solution that is described in patch 4 (uuid=auto) that > meets all the requirement above. > There is an xfstest to test the persistent-unique fsid feature [3]. > > This patch set has been in overlayfs-next for soaking since v6.5-rc1. > If you have any reservations that we will not be able to resolve in time > for 6.6, especially regarding the on-disk format and backward compat, > we could also merge only patch 1 and leave the fsid patches for later. > Hi Miklos, Any comments on this series (which is currently on overlayfs-next)? Please let me know if you want me to take care of the 6.6 PR or if you intend to prepare it yourself. Other candidates for 6.6 include: - ovl lock re-ordering https://lore.kernel.org/linux-unionfs/20230720153731.420290-1-amir73il@xxxxxxxxx/ - CONFIG_OVERLAY_FS_DEBUG https://lore.kernel.org/linux-unionfs/20230521082813.17025-1-andrea.righi@xxxxxxxxxxxxx/ Thanks, Amir. > > [1] https://lore.kernel.org/linux-fsdevel/20230425130105.2606684-1-amir73il@xxxxxxxxx/ > [2] https://github.com/amir73il/ltp/commits/ovl_encode_fid > [3] https://github.com/amir73il/xfstests/commits/ovl_fsid > > > Amir Goldstein (4): > ovl: support encoding non-decodable file handles > ovl: add support for unique fsid per instance > ovl: store persistent uuid/fsid with uuid=on > ovl: auto generate uuid for new overlay filesystems > > Documentation/filesystems/overlayfs.rst | 25 ++++++++++ > fs/overlayfs/copy_up.c | 2 +- > fs/overlayfs/export.c | 26 ++++++++--- > fs/overlayfs/inode.c | 2 +- > fs/overlayfs/namei.c | 5 +- > fs/overlayfs/overlayfs.h | 22 +++++++++ > fs/overlayfs/ovl_entry.h | 3 +- > fs/overlayfs/params.c | 31 +++++++++++-- > fs/overlayfs/super.c | 29 ++++++++++-- > fs/overlayfs/util.c | 61 +++++++++++++++++++++++++ > 10 files changed, 186 insertions(+), 20 deletions(-) > > -- > 2.34.1 >
