• Eric Sandeen's avatar
    ext4: limit block allocations for indirect-block files to < 2^32 · fb0a387d
    Eric Sandeen authored
    Today, the ext4 allocator will happily allocate blocks past
    2^32 for indirect-block files, which results in the block
    numbers getting truncated, and corruption ensues.
    
    This patch limits such allocations to < 2^32, and adds
    BUG_ONs if we do get blocks larger than that.
    
    This should address RH Bug 519471, ext4 bitmap allocator 
    must limit blocks to < 2^32
    
    * ext4_find_goal() is modified to choose a goal < UINT_MAX,
      so that our starting point is in an acceptable range.
    
    * ext4_xattr_block_set() is modified such that the goal block
      is < UINT_MAX, as above.
    
    * ext4_mb_regular_allocator() is modified so that the group
      search does not continue into groups which are too high
    
    * ext4_mb_use_preallocated() has a check that we don't use
      preallocated space which is too far out
    
    * ext4_alloc_blocks() and ext4_xattr_block_set() add some BUG_ONs
    
    No attempt has been made to limit inode locations to < 2^32,
    so we may wind up with blocks far from their inodes.  Doing
    this much already will lead to some odd ENOSPC issues when the
    "lower 32" gets full, and further restricting inodes could
    make that even weirder.
    
    For high inodes, choosing a goal of the original, % UINT_MAX,
    may be a bit odd, but then we're in an odd situation anyway,
    and I don't know of a better heuristic.
    Signed-off-by: default avatarEric Sandeen <sandeen@redhat.com>
    Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
    fb0a387d
mballoc.c 132 KB