git: sbin/hammer: Add hammer strip command

[Tomohiro Kusumi]

commit 2eccaef52dab614a753aba8029714fe5424c26e1
Author: Tomohiro Kusumi <kusumi.tomohiro at gmail.com>
Date:   Sun Dec 4 18:57:15 2016 +0900

    sbin/hammer: Add hammer strip command
    
    This command is inspired by hammer recover command, and does
    opposite of what recover command does.
    
    This command zero clears zone-8(B-Tree) big-blocks, zone-9(meta)
    big-blocks, and then the whole volume header, except that volume
    signature field is overwritten with "STRIPPED" instead of zeros.
    After running, a filesystem is no longer mountable or recoverable
    with hammer recover command. This command is also fast as it only
    zero clears good enough ondisk data to make it unmountable and
    unrecoverable.
    
    Keep in mind that this command does _not_ zero clear user data.
    Users would normally use a software designed to completely shred
    a filesystem. This command is not designed to shred a filesystem.
    The name "strip" gives better idea of what it really does than
    using "shred"/etc.
    
    -- example
     # newfs_hammer -L TEST /dev/da1 /dev/da2 /dev/da3 > /dev/null
     # mount_hammer /dev/da1:/dev/da2:/dev/da3 /HAMMER
     # cd /HAMMER
     # dd if=/dev/urandom of=./out bs=1M count=120000
     120000+0 records in
     120000+0 records out
     125829120000 bytes transferred in 1766.417077 secs (71234094 bytes/sec)
     # cd
     # umount /HAMMER
     # hammer -f /dev/da1:/dev/da2:/dev/da3 strip
     You have requested that HAMMER filesystem (TEST) be stripped
     Do you really want to do this? [y/n] y
     Stripping HAMMER filesystem (TEST) in 5 4 3 2 1.. starting destruction pass
     8000000021000000
     9000000021800000
     800000019c000000
     800000030c000000
     800000047e000000
     80000005f7000000
     8000000767000000
     80000008d8000000
     8000000a51800000
     8000000bc5000000
     8000000d37800000
     8000000ead000000
     800000101e800000
     8000001193000000
     8000001304000000
     8000001478800000
     80000015ee000000
     8000001760800000
     80000018d1800000
     8000001a47000000
     8000001bb6000000
     801000013c000000
     /dev/da1
     /dev/da2
     /dev/da3
     # mount_hammer /dev/da1:/dev/da2:/dev/da3 /HAMMER
     mount: Invalid argument
     mount_hammer: /dev/da1: Invalid volume signature 4445505049525453

Summary of changes:
 sbin/hammer/Makefile           |   3 +-
 sbin/hammer/cmd_strip.c        | 181 +++++++++++++++++++++++++++++++++++++++++
 sbin/hammer/hammer.8           |  27 +++++-
 sbin/hammer/hammer.c           |   7 ++
 sbin/hammer/hammer.h           |   1 +
 sys/vfs/hammer/hammer_ondisk.c |   4 +-
 6 files changed, 219 insertions(+), 4 deletions(-)
 create mode 100644 sbin/hammer/cmd_strip.c

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/2eccaef52dab614a753aba8029714fe5424c26e1


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