• Darrick J. Wong's avatar
    xfs: add owner field to extent allocation and freeing · 340785cc
    Darrick J. Wong authored
    For the rmap btree to work, we have to feed the extent owner
    information to the the allocation and freeing functions. This
    information is what will end up in the rmap btree that tracks
    allocated extents. While we technically don't need the owner
    information when freeing extents, passing it allows us to validate
    that the extent we are removing from the rmap btree actually
    belonged to the owner we expected it to belong to.
    
    We also define a special set of owner values for internal metadata
    that would otherwise have no owner. This allows us to tell the
    difference between metadata owned by different per-ag btrees, as
    well as static fs metadata (e.g. AG headers) and internal journal
    blocks.
    
    There are also a couple of special cases we need to take care of -
    during EFI recovery, we don't actually know who the original owner
    was, so we need to pass a wildcard to indicate that we aren't
    checking the owner for validity. We also need special handling in
    growfs, as we "free" the space in the last AG when extending it, but
    because it's new space it has no actual owner...
    
    While touching the xfs_bmap_add_free() function, re-order the
    parameters to put the struct xfs_mount first.
    
    Extend the owner field to include both the owner type and some sort
    of index within the owner.  The index field will be used to support
    reverse mappings when reflink is enabled.
    
    When we're freeing extents from an EFI, we don't have the owner
    information available (rmap updates have their own redo items).
    xfs_free_extent therefore doesn't need to do an rmap update. Make
    sure that the log replay code signals this correctly.
    
    This is based upon a patch originally from Dave Chinner. It has been
    extended to add more owner information with the intent of helping
    recovery operations when things go wrong (e.g. offset of user data
    block in a file).
    
    [dchinner: de-shout the xfs_rmap_*_owner helpers]
    [darrick: minor style fixes suggested by Christoph Hellwig]
    Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
    Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
    Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
    Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
    340785cc
xfs_bmap_btree.c 22.4 KB