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Diffstat (limited to 'Documentation/filesystems/overlayfs.rst')
| -rw-r--r-- | Documentation/filesystems/overlayfs.rst | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst index b63e0db03631..d55381d3fa0f 100644 --- a/Documentation/filesystems/overlayfs.rst +++ b/Documentation/filesystems/overlayfs.rst @@ -657,6 +657,22 @@ can be useful in case the underlying disk is copied and the UUID of this copy is changed. This is only applicable if all lower/upper/work directories are on the same filesystem, otherwise it will fallback to normal behaviour. + +UUID and fsid +------------- + +The UUID of overlayfs instance itself and the fsid reported by statfs(2) are +controlled by the "uuid" mount option, which supports these values: + +- "null": (default) + UUID of overlayfs is null. fsid is taken from upper most filesystem. +- "off": + UUID of overlayfs is null. fsid is taken from upper most filesystem. + UUID of underlying layers is ignored. +- "on": + UUID of overlayfs is generated and used to report a unique fsid. + + Volatile mount -------------- |