0826f9073a
Add basic backing image support to the block-format mechanism. This is a functionality checkpoint that enables the raw mechanism required to support client driven "snapshot" and "clone" requests. This change enhances the block-format setxattr command to support an additional and optional backing image reference. For example: setxattr -n trusted.glusterfs.block-format -v "qcow2:10GB:<bimg>" ./newimage ... where <bimg> refers to the backing image for unallocated blocks in newimage. <bimg> can be provided in one of two formats: - a gfid string in the following format (assuming a valid gfid): <gfid:00000000-0000-0000-0000-000000000000> - or a filename that must be resident in the same directory as the new clone file being formatted. E.g., setxattr -n trusted.glusterfs.block-format -v "qcow2:10GB:baseimg" ./newimage This latter format is more restrictive, simply provided for convenience or until something more refined is available. This change makes no assumptions about the backing image file and affords no additional protection. It is up to the user/client to recognize the relationship between the files and manage them appropriately (i.e., no writes to the backing image, etc.). BUG: 986775 Change-Id: I7aff7bdc59b85a6459001a6bfeae4db6bf74f703 Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-on: http://review.gluster.org/5967 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Anand Avati <avati@redhat.com>
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