From f168f1098dd9038daaf9f7be5f81cdea4985886a Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Fri, 19 Jan 2018 11:26:53 +0200 Subject: ovl: add support for "nfs_export" configuration Introduce the "nfs_export" config, module and mount options. The NFS export feature depends on the "index" feature and enables two implicit overlayfs features: "index_all" and "verify_lower". The "index_all" feature creates an index on copy up of every file and directory. The "verify_lower" feature uses the full index to detect overlay filesystems inconsistencies on lookup, like redirect from multiple upper dirs to the same lower dir. NFS export can be enabled for non-upper mount with no index. However, because lower layer redirects cannot be verified with the index, enabling NFS export support on an overlay with no upper layer requires turning off redirect follow (e.g. "redirect_dir=nofollow"). The full index may incur some overhead on mount time, especially when verifying that lower directory file handles are not stale. NFS export support, full index and consistency verification will be implemented by following patches. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi --- fs/overlayfs/ovl_entry.h | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/overlayfs/ovl_entry.h') diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h index 608e48755070..6dd60fcf8cb7 100644 --- a/fs/overlayfs/ovl_entry.h +++ b/fs/overlayfs/ovl_entry.h @@ -17,6 +17,7 @@ struct ovl_config { bool redirect_follow; const char *redirect_mode; bool index; + bool nfs_export; }; struct ovl_layer { -- cgit v1.2.3-59-g8ed1b