0be0bfd2de
Once upon a time, commit2cac0c00a6("ovl: get exclusive ownership on upper/work dirs") in v4.13 added some sanity checks on overlayfs layers. This change caused a docker regression. The root cause was mount leaks by docker, which as far as I know, still exist. To mitigate the regression, commit85fdee1eef("ovl: fix regression caused by exclusive upper/work dir protection") in v4.14 turned the mount errors into warnings for the default index=off configuration. Recently, commit146d62e5a5("ovl: detect overlapping layers") in v5.2, re-introduced exclusive upper/work dir checks regardless of index=off configuration. This changes the status quo and mount leak related bug reports have started to re-surface. Restore the status quo to fix the regressions. To clarify, index=off does NOT relax overlapping layers check for this ovelayfs mount. index=off only relaxes exclusive upper/work dir checks with another overlayfs mount. To cover the part of overlapping layers detection that used the exclusive upper/work dir checks to detect overlap with self upper/work dir, add a trap also on the work base dir. Link: https://github.com/moby/moby/issues/34672 Link: https://lore.kernel.org/linux-fsdevel/20171006121405.GA32700@veci.piliscsaba.szeredi.hu/ Link: https://github.com/containers/libpod/issues/3540 Fixes:146d62e5a5("ovl: detect overlapping layers") Cc: <stable@vger.kernel.org> # v4.19+ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Tested-by: Colin Walters <walters@verbum.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.