finding alternate superblocks in ffs

From: Christoph P. Kukulies (kuku_at_kukulies.org)
Date: 10/31/04

  • Next message: Maxim Konovalov: "Re: finding alternate superblocks in ffs" 
    Date: Sun, 31 Oct 2004 12:42:10 +0100
To: hackers@freebsd.org

    Yesterday a major desaster happened: I stumbled across the power cable of my
    Dell Inspiron notebook. The notebook fell to the floor. FreeBSD was running
    at that time. Nothing seemed to got damaged, just a palm rest popped off.

    Ah yes, the HD bay sprung off and in a moment of reflex I pushed it
    in again in the running system. After that I tried to mount the
    disk (which had not been mounted at that point of time). Anyway,
    trying to

    # fsck_ffs /dev/ad2s1e
    ** /dev/ad2s1e
    Cannot find file system superblock

    LOOK FOR ALTERNATE SUPERBLOCKS? [yn] y

    32 is not a file system superblock
    89808 is not a file system superblock
    179584 is not a file system superblock
    269360 is not a file system superblock
    359136 is not a file system superblock
    448912 is not a file system superblock
    538688 is not a file system superblock
    628464 is not a file system superblock
    718240 is not a file system superblock
    808016 is not a file system superblock

    ....
    20813728 is not a file system superblock
    20903504 is not a file system superblock
    20993280 is not a file system superblock
    21083056 is not a file system superblock
    21172832 is not a file system superblock
    21262608 is not a file system superblock
    SEARCH FOR ALTERNATE SUPER-BLOCK FAILED. YOU MUST USE THE
    -b OPTION TO FSCK TO SPECIFY THE LOCATION OF AN ALTERNATE
    SUPER-BLOCK TO SUPPLY NEEDED INFORMATION; SEE fsck(8).
    #

    Any idea what I can do now?

    I wrote a little program that opens /dev/ad2s1e

    #include <stdio.h>
    #include <sys/param.h>
    #include <sys/stat.h>
    #include <sys/file.h>
    #include <sys/time.h>
    #include <sys/mount.h>
    #include <sys/resource.h>
    #include <sys/sysctl.h>
    #include <sys/disklabel.h>

    #include <ufs/ufs/dinode.h>
    #include <ufs/ufs/ufsmount.h>
    #include <ufs/ffs/fs.h>
     

    #include <fcntl.h>
    #include <ufs/ffs/fs.h>
    main(){
      int fd;
      int k,i=0;
      int buf[512/(sizeof (int))];
      if((fd=open("/dev/ad2s1e",O_RDONLY)) < 0)
          printf("error opening device\n"),exit(2);
      printf("opened device\n");
      while(read(fd,buf,512)>0){
        for(k=0;k<(512/(sizeof (int)));k++){
           /*if(buf[k]==FS_UFS1_MAGIC)
               printf("UFS1 * %d\n",i),fflush(stdout); */
           if(buf[k]==FS_UFS2_MAGIC)
               printf("UFS2 * %d\n",i),fflush(stdout);
           i++;
         }
        }
    }

    I'm not sure whether my approach is correct.
    Anyway, the blocks I find with that method
    aren't recognized as superblocks either. 

    --
Chris Christoph P. U. Kukulies kuku_at_kukulies.org
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  • Next message: Maxim Konovalov: "Re: finding alternate superblocks in ffs"

    Relevant Pages

    • Re: finding alternate superblocks in ffs
      ... sysinstall, and then Toggle Newfs off, and write changes. ... > Dell Inspiron notebook. ... > in again in the running system. ... > Cannot find file system superblock ...
      (freebsd-hackers)
    • Re: finding alternate superblocks in ffs
      ... >> Dell Inspiron notebook. ... The notebook fell to the floor. ... FreeBSD was running ... fsck says it cannot read lotsa blocks). ...
      (freebsd-hackers)
    • Re: finding alternate superblocks in ffs
      ... > Dell Inspiron notebook. ... The notebook fell to the floor. ... FreeBSD was running ... you can recreate the options used on your FS to begin with)? ...
      (freebsd-hackers)