• Chris Mason's avatar
    Btrfs: stop providing a bmap operation to avoid swapfile corruptions · 35054394
    Chris Mason authored
    Swapfiles use bmap to build a list of extents belonging to the file,
    and they assume these extents won't change over the life of the file.
    They also use resulting list to do IO directly to the block device.
    
    This causes problems for btrfs in a few ways:
    
    btrfs returns logical block numbers through bmap, and these are not suitable
    for IO.  They might translate to different devices, raid etc.
    
    COW means that file block mappings are going to change frequently.
    
    Using swapfiles on btrfs will lead to corruption, so we're avoiding the
    problem for now by dropping bmap support entirely.  A later commit
    will add fiemap support for people that really want to know how
    a file is laid out.
    Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
    35054394
inode.c 134 KB