From: "Theodore Ts'o" <tytso@mit.edu>

This patch versus improves the output produced by "echo 1 >
/proc/sys/vm/block_dump", in the following ways:

1) The messages are printed with KERN_DEBUG, so that even if sysklogd is
   running, if configured appropriately, it will not need to write to log
   files.

2) The inode which is dirtied by a process is now identified more
   precisely by inode number and filesystem ID, and by a dcache name if
   present.

3) In the generic filesystem sget function, the superblock id (s_id) is
   filled in with the filesystem type by default.  Filesystems which are
   block-device based will override s_id, but this allows pseudo
   filesystems such as tmpfs, procfs, etc.  to be identified in (2).