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    ocfs2: Allow smaller allocations during large writes · 415cb800
    Mark Fasheh 提交于
    The ocfs2 write code loops through a page much like the block code, except
    that ocfs2 allocation units can be any size, including larger than page
    size. Typically it's equal to or larger than page size - most kernels run 4k
    pages, the minimum ocfs2 allocation (cluster) size.
    
    Some changes introduced during 2.6.23 changed the way writes to pages are
    handled, and inadvertantly broke support for > 4k page size. Instead of just
    writing one cluster at a time, we now handle the whole page in one pass.
    
    This means that multiple (small) seperate allocations might happen in the
    same pass. The allocation code howver typically optimizes by getting the
    maximum which was reserved. This triggered a BUG_ON in the extend code where
    it'd ask for a single bit (for one part of a > 4k page) and get back more
    than it asked for.
    
    Fix this by providing a variant of the high level allocation function which
    allows the caller to specify a maximum. The traditional function remains and
    just calls the new one with a maximum determined from the initial
    reservation.
    Signed-off-by: NMark Fasheh <mark.fasheh@oracle.com>
    415cb800
file.c 56.5 KB