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    jbd2: add support for avoiding data writes during transaction commits · 41617e1a
    Jan Kara 提交于
    Currently when filesystem needs to make sure data is on permanent
    storage before committing a transaction it adds inode to transaction's
    inode list. During transaction commit, jbd2 writes back all dirty
    buffers that have allocated underlying blocks and waits for the IO to
    finish. However when doing writeback for delayed allocated data, we
    allocate blocks and immediately submit the data. Thus asking jbd2 to
    write dirty pages just unnecessarily adds more work to jbd2 possibly
    writing back other redirtied blocks.
    
    Add support to jbd2 to allow filesystem to ask jbd2 to only wait for
    outstanding data writes before committing a transaction and thus avoid
    unnecessary writes.
    Signed-off-by: NJan Kara <jack@suse.cz>
    Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
    41617e1a
journal.c 75.2 KB