• Sascha Hauer's avatar
    ubi: Fix producing anchor PEBs · f9c34bb5
    Sascha Hauer authored
    When a new fastmap is about to be written UBI must make sure it has a
    free block for a fastmap anchor available. For this ubi_update_fastmap()
    calls ubi_ensure_anchor_pebs(). This stopped working with 2e8f08de
    ("ubi: Fix races around ubi_refill_pools()"), with this commit the wear
    leveling code is blocked and can no longer produce free PEBs. UBI then
    more often than not falls back to write the new fastmap anchor to the
    same block it was already on which means the same erase block gets
    erased during each fastmap write and wears out quite fast.
    
    As the locking prevents us from producing the anchor PEB when we
    actually need it, this patch changes the strategy for creating the
    anchor PEB. We no longer create it on demand right before we want to
    write a fastmap, but instead we create an anchor PEB right after we have
    written a fastmap. This gives us enough time to produce a new anchor PEB
    before it is needed. To make sure we have an anchor PEB for the very
    first fastmap write we call ubi_ensure_anchor_pebs() during
    initialisation as well.
    
    Fixes: 2e8f08de ("ubi: Fix races around ubi_refill_pools()")
    Signed-off-by: default avatarSascha Hauer <s.hauer@pengutronix.de>
    Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
    f9c34bb5
ubi.h 41.1 KB