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Sometimes it is interesting to know if an upper file is pure upper or a copy up target, and if it is a copy up target, it may be interesting to find the copy up origin. This will be used to preserve lower inode numbers across copy up. Store the lower inode file handle in upper inode extended attribute overlay.origin on copy up to use it later for these cases. Store the lower filesystem uuid along side the file handle, so we can validate that we are looking for the origin file in the original fs. If lower fs does not support NFS export ops store a zero sized xattr so we can always use the overlay.origin xattr to distinguish between a copy up and a pure upper inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.