fsck of large volume with small memory

[sam]

Don Lewis wrote:
> On 24 Sep, sam wrote:
>   
> Expect major file system lossage ...
> I think this patch could be better, but this should get you going ...
>
> Index: sbin/fsck_ffs/pass1.c
> ===================================================================
> RCS file: /home/ncvs/src/sbin/fsck_ffs/pass1.c,v
> retrieving revision 1.43
> diff -u -r1.43 pass1.c
> --- sbin/fsck_ffs/pass1.c	8 Oct 2004 20:44:47 -0000	1.43
> +++ sbin/fsck_ffs/pass1.c	24 Sep 2007 23:15:22 -0000
> @@ -93,9 +93,29 @@
>  		inumber = c * sblock.fs_ipg;
>  		setinodebuf(inumber);
>  		getblk(&cgblk, cgtod(&sblock, c), sblock.fs_cgsize);
> -		if (sblock.fs_magic == FS_UFS2_MAGIC)
> +		if (sblock.fs_magic == FS_UFS2_MAGIC) {
>  			inosused = cgrp.cg_initediblk;
> -		else
> +                        if (inosused < 0 || inosused > sblock.fs_ipg) {
> +				pfatal("CG %d: PREPOSTEROUS NUMBER OF INODES %d (cg_initediblk), ASSUMING %d (fs_ipg)\n",
> +				    c, inosused, sblock.fs_ipg);
> +				/*
> +				 * The cylinder group block is most likely
> +				 * totally corrupted and will probably
> +				 * fail the magic number check below as well.
> +				 * Ignoring cg_initediblk and setting
> +				 * inosused to sblock.fs_ipg will allow
> +				 * a manual fsck to proceed further instead
> +				 * of dying when it attempts to allocate
> +				 * an insane amount of memory to store
> +				 * the inode info for this cylinder group.
> +				 * This may provide enough information
> +				 * to allow the system administrator to
> +				 * do a better job of patching the
> +				 * filesystem with fsdb.
> +				 */
> +				inosused = sblock.fs_ipg;
> +			}
> +		} else
>  			inosused = sblock.fs_ipg;
>  		if (got_siginfo) {
>  			printf("%s: phase 1: cyl group %d of %d (%d%%)\n",
>
>
>   
after patching

======================================================
# fsck /dev/aacd0s1f
** /dev/aacd0s1f (NO WRITE)
** Last Mounted on /usr
** Phase 1 - Check Blocks and Sizes
CG 124: PREPOSTEROUS NUMBER OF INODES 1668246575 (cg_initediblk), 
ASSUMING 23552 (fs_ipg)

UNEXPECTED SOFT UPDATE INCONSISTENCY
** Phase 2 - Check Pathnames
UNALLOCATED  I=2732216  OWNER=svn MODE=40755
SIZE=512 MTIME=Sep  4 12:22 2007
DIR=/home/svn

UNEXPECTED SOFT UPDATE INCONSISTENCY

REMOVE? no

UNALLOCATED  I=2732189  OWNER=venom MODE=40755
SIZE=512 MTIME=Sep  3 17:16 2007
DIR=/home/venom/svn

UNEXPECTED SOFT UPDATE INCONSISTENCY

REMOVE? no

UNALLOCATED  I=2732248  OWNER=root MODE=40755
SIZE=512 MTIME=Sep 14 19:03 2007
DIR=/home/venom/temp/devel/trunk

 *** DELETE OUTPUT ***

** Phase 3 - Check Connectivity
UNREF DIR  I=2755667  OWNER=games MODE=40750
SIZE=1536 MTIME=Jul 19 16:45 2007
RECONNECT? no

UNREF DIR  I=2755600  OWNER=games MODE=40750
SIZE=1024 MTIME=Jul 19 16:45 2007
RECONNECT? no

UNREF DIR  I=2755628  OWNER=games MODE=40750
SIZE=1536 MTIME=Jul 19 16:45 2007
RECONNECT? no

UNREF DIR  I=2755584  OWNER=games MODE=40750
SIZE=512 MTIME=Jul 19 16:45 2007
RECONNECT? no

** Phase 4 - Check Reference Counts
UNREF FILE I=541705  OWNER=root MODE=100555
SIZE=218296 MTIME=Sep 10 14:51 2007
CLEAR? no

UNREF FILE I=541950  OWNER=root MODE=100555
SIZE=37832 MTIME=Sep 10 14:52 2007
CLEAR? no

 *** DELETE OUTPUT ***

UNREF FILE I=4875961  OWNER=root MODE=100444
SIZE=35552 MTIME=Sep 10 14:50 2007
CLEAR? no

UNREF FILE I=6312454  OWNER=root MODE=104555
SIZE=15880 MTIME=Sep 10 14:52 2007
CLEAR? no

** Phase 5 - Check Cyl groups
CG 116: BAD MAGIC NUMBER

UNEXPECTED SOFT UPDATE INCONSISTENCY
FREE BLK COUNT(S) WRONG IN SUPERBLK
SALVAGE? no

SUMMARY INFORMATION BAD
SALVAGE? no

BLK(S) MISSING IN BIT MAPS
SALVAGE? no

CG 124: BAD MAGIC NUMBER

UNEXPECTED SOFT UPDATE INCONSISTENCY
LOST 74 DIRECTORIES

UNEXPECTED SOFT UPDATE INCONSISTENCY
fsck: /dev/aacd0s1f: Segmentation fault: 11
#
======================================================

/Vladimir Ermakov