Kir Kolyshkin 8422d85087 overlay2: use index=off if possible ... As pointed out in https://github.com/moby/moby/issues/37970, Docker overlay driver can't work with index=on feature of the Linux kernel "overlay" filesystem. In case the global default is set to "yes", Docker will fail with EBUSY when trying to mount, like this: > error creating overlay mount to ...../merged: device or resource busy and the kernel log should contain something like: > overlayfs: upperdir is in-use by another mount, mount with > '-o index=off' to override exclusive upperdir protection. A workaround is to set index=off in overlay kernel module parameters, or even recompile the kernel with CONFIG_OVERLAY_FS_INDEX=n in .config. Surely this is not always practical or even possible. The solution, as pointed out my Amir Goldstein (as well as the above kernel message:) is to use 'index=off' option when mounting. NOTE since older (< 4.13rc1) kernels do not support "index=" overlayfs parameter, try to figure out whether the option is supported. In case it's not possible to figure out, assume it is not. NOTE the default can be changed anytime (by writing to /sys/module/overlay/parameters/index) so we need to always use index=off. [v2: move the detection code to Init()] [v3: don't set index=off if stat() failed] Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>		2018-10-11 12:52:57 -07:00
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check.go	overlay2: use global logger instance	2018-10-11 12:50:45 -07:00
mount.go	Add canonical import comment	2018-02-05 16:51:57 -05:00
overlay.go	overlay2: use index=off if possible	2018-10-11 12:52:57 -07:00
overlay_test.go	Update overlay2 to use naive diff for changes	2018-06-20 11:07:36 -07:00
overlay_unsupported.go	Add canonical import comment	2018-02-05 16:51:57 -05:00
randomid.go	overlay2: use global logger instance	2018-10-11 12:50:45 -07:00