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Heinz Mauelshagen authored
Add raid level takeover support allowing arbitrary takeovers between raid levels supported by md personalities (i.e. raid0, raid1/10 and raid4/5/6): - add rs_config_{backup|restore} function to allow for temporary storing ctr requested layout changes and restore them for takeover conersion decision after the superblocks got loaded and analyzed - add members to store layout to 'struct raid_set' (not mandatory for takeover but needed for reshape in later patch) - add rebuild_disks bitfield to 'struct raid_set' and set bits in ctr to use in setting up takeover (base to address a 'rebuild' related raid_status() table line bug and needed as well for reshape in future patch) - add runtime flags and respective manipulation functions to be able to control e.g. wrting of superlocks to the preresume function on takeover and (later) reshape - add functions to detect takeover, check it's valid (mandatory here to avoid failing on md_run()), setup for it and use in the ctr; those will be likely moved out once reshaping gets added to simplify the ctr - start raid set readonly in ctr and switch to readwrite, optionally updating superblocks, in preresume in order to allow suspend to quiesce any active table before (which involves superblock updates); this ensures the proper sequence of writing the current and any new takeover(/reshape) metadata Signed-off-by:
Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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