Changes since v1: - Provide info about trusted.overlay.metacopy extended attribute. - Minor rephrasing regarding copy-up operation with metacopy=on Signed-off-by: Yuriy Belikov <yuriybelikov1@xxxxxxxxx> --- Documentation/filesystems/overlayfs.rst | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst index 165514401441..e5ad43f4f4d7 100644 --- a/Documentation/filesystems/overlayfs.rst +++ b/Documentation/filesystems/overlayfs.rst @@ -367,8 +367,11 @@ Metadata only copy up When the "metacopy" feature is enabled, overlayfs will only copy up metadata (as opposed to whole file), when a metadata specific operation -like chown/chmod is performed. Full file will be copied up later when -file is opened for WRITE operation. +like chown/chmod is performed. An upper file in this state is marked with +"trusted.overlayfs.metacopy" xattr which indicates that the upper file +contains no data. Full data will be copied up later when file is opened for +WRITE operation. After the lower file's data is copied up, +the "trusted.overlayfs.metacopy" xattr is removed from the upper file. In other words, this is delayed data copy up operation and data is copied up when there is a need to actually modify data. -- 2.43.5
