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| -rw-r--r-- | Documentation/filesystems/overlayfs.rst | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst index 1ef4ef38b542..b86be7c6a952 100644 --- a/Documentation/filesystems/overlayfs.rst +++ b/Documentation/filesystems/overlayfs.rst @@ -469,14 +469,18 @@ summarized in the `Inode properties`_ table above. Changes to underlying filesystems --------------------------------- -Offline changes, when the overlay is not mounted, are allowed to either -the upper or the lower trees. - Changes to the underlying filesystems while part of a mounted overlay filesystem are not allowed. If the underlying filesystem is changed, the behavior of the overlay is undefined, though it will not result in a crash or deadlock. +Offline changes, when the overlay is not mounted, are allowed to the +upper tree. Offline changes to the lower tree are only allowed if the +"metadata only copy up", "inode index", and "redirect_dir" features +have not been used. If the lower tree is modified and any of these +features has been used, the behavior of the overlay is undefined, +though it will not result in a crash or deadlock. + When the overlay NFS export feature is enabled, overlay filesystems behavior on offline changes of the underlying lower layer is different than the behavior when NFS export is disabled. |