Enable NFS export support if the "verify" feature is enabled. Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> --- fs/overlayfs/Kconfig | 2 ++ fs/overlayfs/super.c | 8 ++++++++ 2 files changed, 10 insertions(+) diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig index 0e4764ed4e23..c63473677c95 100644 --- a/fs/overlayfs/Kconfig +++ b/fs/overlayfs/Kconfig @@ -67,6 +67,8 @@ config OVERLAY_FS_VERIFY The verify feature prevents multiple redirects to the same lower dir and prevents broken hardlinks from using the same inode number. + The verify feature is required for exporting an overlay filesystem + subtree as an NFS share. Note, that verify feature is not backward compatible. That is, mounting an overlay with verification index entries on a kernel diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 1bc37bc23e89..28596d0a53d2 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -1316,6 +1316,14 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) ofs->config.verify = false; } + /* + * NFS export requires that all layers support file handles and that + * all files and dirs are indexed on copy up (verify=on). We already + * check that all layers support file handles for enabling index. + */ + if (ofs->config.verify) + sb->s_export_op = &ovl_export_operations; + /* Never override disk quota limits or use reserved space */ cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); -- 2.7.4
