• Qu Wenruo's avatar
    btrfs: submit read time repair only for each corrupted sector · 150e4b05
    Qu Wenruo authored
    Currently btrfs_submit_read_repair() has some extra check on whether the
    failed bio needs extra validation for repair.  But we can avoid all
    these extra mechanisms if we submit the repair for each sector.
    
    By this, each read repair can be easily handled without the need to
    verify which sector is corrupted.
    
    This will also benefit subpage, as one subpage bvec can contain several
    sectors, making the extra verification more complex.
    
    So this patch will:
    
    - Introduce repair_one_sector()
      The main code submitting repair, which is more or less the same as old
      btrfs_submit_read_repair().
      But this time, it only repairs one sector.
    
    - Make btrfs_submit_read_repair() to handle sectors differently
      There are 3 different cases:
    
      * Good sector
        We need to release the page and extent, set the range uptodate.
    
      * Bad sector and failed to submit repair bio
        We need to release the page and extent, but not set the range
        uptodate.
    
      * Bad sector but repair bio submitted
        The page and extent release will be handled by the submitted repair
        bio. Nothing needs to be done.
    
      Since btrfs_submit_read_repair() will handle the page and extent
      release now, we need to skip to next bvec even we hit some error.
    
    - Change the lifespan of @uptodate in end_bio_extent_readpage()
      Since now btrfs_submit_read_repair() will handle the full bvec
      which contains any corruption, we don't need to bother updating
      @uptodate bit anymore.
      Just let @uptodate to be local variable inside the main loop,
      so that any error from one bvec won't affect later bvec.
    
    - Only export btrfs_repair_one_sector(), unexport
      btrfs_submit_read_repair()
      The only outside caller for read repair is DIO, which already submits
      its repair for just one sector.
      Only export btrfs_repair_one_sector() for DIO.
    
    This patch will focus on the change on the repair path, the extra
    validation code is still kept as is, and will be cleaned up later.
    Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
    Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
    150e4b05
extent_io.c 187 KB