Overlayfs: turn on metadata only copy up feature by default
configname: CONFIG_OVERLAY_FS_METACOPY
Linux Kernel Configuration
└─>File systems
└─>Overlayfs: turn on metadata only copy up feature by default
In linux kernel since version 4.2 (release Date: 2015-08-30)
If this config option is enabled then overlay filesystems will
copy up only metadata where appropriate and data copy up will
happen when a file is opened for WRITE operation. It is still
possible to turn off this feature globally with the "metacopy=off"
module option or on a filesystem instance basis with the
"metacopy=off" mount option.
Note, that this feature is not backward compatible. That is,
mounting an overlay which has metacopy only inodes on a kernel
that doesn't support this feature will have unexpected results.
If unsure, say N.
copy up only metadata where appropriate and data copy up will
happen when a file is opened for WRITE operation. It is still
possible to turn off this feature globally with the "metacopy=off"
module option or on a filesystem instance basis with the
"metacopy=off" mount option.
Note, that this feature is not backward compatible. That is,
mounting an overlay which has metacopy only inodes on a kernel
that doesn't support this feature will have unexpected results.
If unsure, say N.