[src/trunk]: src/sbin/fsck_ffs Only check relevant fields when comparing the ...

[fvdl <fvdl%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/cc42800083d4
branches:  trunk
changeset: 543273:cc42800083d4
user:      fvdl <fvdl%NetBSD.org@localhost>
date:      Fri Feb 21 15:15:49 2003 +0000

description:
Only check relevant fields when comparing the superblock to an alternate
superblock. Avoids false positives should fsck_ffs be run on a filesystem
that was created after the UFS2 code has been merged.

This commit is mostly a forward compatibility patch that can be pulled
up in to the 1.6 branch.

>From Kirk Mckusick in FreeBSD (setup.c rev. 1.30). Original commit message:
========
When checking the alternate superblock, we used to copy any fields
that might have changed, then did a byte-by-byte comparison with
the alternate. If any unused fields got used, they had to be added
to the exception list. Such changes caused too many false alarms.
So, I have changed the comparison algorithm to compare a selected
set of fields that are not expected to change. This new algorithm
causes far fewer false hits and still does a good job of detecting
problems when they have really occurred. In particular, this change
should ease the transition to kernels supporting UFS2 which make
some significant changes to the superblock.

Sponsored by:   DARPA, NAI Labs
========

diffstat:

 sbin/fsck_ffs/setup.c |  84 +++++++++++++++++++-------------------------------
 1 files changed, 32 insertions(+), 52 deletions(-)

diffs (124 lines):

diff -r d91c610cec0f -r cc42800083d4 sbin/fsck_ffs/setup.c
--- a/sbin/fsck_ffs/setup.c     Fri Feb 21 15:14:08 2003 +0000
+++ b/sbin/fsck_ffs/setup.c     Fri Feb 21 15:15:49 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: setup.c,v 1.56 2003/01/24 21:55:09 fvdl Exp $  */
+/*     $NetBSD: setup.c,v 1.57 2003/02/21 15:15:49 fvdl Exp $  */
 
 /*
  * Copyright (c) 1980, 1986, 1993
@@ -38,7 +38,7 @@
 #if 0
 static char sccsid[] = "@(#)setup.c    8.10 (Berkeley) 5/9/95";
 #else
-__RCSID("$NetBSD: setup.c,v 1.56 2003/01/24 21:55:09 fvdl Exp $");
+__RCSID("$NetBSD: setup.c,v 1.57 2003/02/21 15:15:49 fvdl Exp $");
 #endif
 #endif /* not lint */
 
@@ -638,9 +638,6 @@
                { badsb(listerr, "NCG OUT OF RANGE"); return (0); }
        if (sblock->fs_cpg < 1)
                { badsb(listerr, "CPG OUT OF RANGE"); return (0); }
-       if (sblock->fs_ncg * sblock->fs_cpg < sblock->fs_ncyl ||
-           (sblock->fs_ncg - 1) * sblock->fs_cpg >= sblock->fs_ncyl)
-               { badsb(listerr, "NCYL LESS THAN NCG*CPG"); return (0); }
        if (sblock->fs_sbsize > SBSIZE)
                { badsb(listerr, "SIZE PREPOSTEROUSLY LARGE"); return (0); }
        /*
@@ -657,8 +654,8 @@
                return (1);
        }
        /*
-        * Set all possible fields that could differ, then do check
-        * of whole super block against an alternate super block.
+        * Compare all fields that should not differ in the alternat super-
+        * block.
         * When an alternate super-block is specified this check is skipped.
         */
        getblk(&asblk, cgsblock(sblock, sblock->fs_ncg - 1), sblock->fs_sbsize);
@@ -704,56 +701,39 @@
 {
 
        /*
-        * Copy fields which we don't care if they're different in the
-        * alternate superblocks, as they're either likely to be
+        * Don't compare fields of which we don't care if they're different
+        * in the alternate superblocks, as they're either likely to be
         * different because they're per-cylinder-group specific, or
         * because they're transient details which are only maintained
         * in the primary superblock.
         */
-       asb->fs_firstfield = sb->fs_firstfield;
-       asb->fs_unused_1 = sb->fs_unused_1;
-       asb->fs_time = sb->fs_time;
-       asb->fs_cstotal = sb->fs_cstotal;
-       asb->fs_cgrotor = sb->fs_cgrotor;
-       asb->fs_fmod = sb->fs_fmod;
-       asb->fs_clean = sb->fs_clean;
-       asb->fs_ronly = sb->fs_ronly;
-       asb->fs_flags = sb->fs_flags;
-       asb->fs_maxcontig = sb->fs_maxcontig;
-       asb->fs_minfree = sb->fs_minfree;
-       asb->fs_optim = sb->fs_optim;
-       asb->fs_rotdelay = sb->fs_rotdelay;
-       asb->fs_maxbpg = sb->fs_maxbpg;
-       memmove(asb->fs_ocsp, sb->fs_ocsp, sizeof sb->fs_ocsp);
-       asb->fs_contigdirs = sb->fs_contigdirs;
-       asb->fs_csp = sb->fs_csp;
-       asb->fs_maxcluster = sb->fs_maxcluster;
-       memmove(asb->fs_fsmnt, sb->fs_fsmnt, sizeof sb->fs_fsmnt);
-       memmove(asb->fs_snapinum,
-               sb->fs_snapinum, sizeof sb->fs_snapinum);
-       asb->fs_avgfilesize = sb->fs_avgfilesize;
-       asb->fs_avgfpdir = sb->fs_avgfpdir;
-       asb->fs_pendingblocks = sb->fs_pendingblocks;
-       asb->fs_pendinginodes = sb->fs_pendinginodes;
-       memmove(asb->fs_sparecon,
-               sb->fs_sparecon, sizeof sb->fs_sparecon);
-       /*
-        * The following should not have to be copied, but need to be.
-        */
-       asb->fs_fsbtodb = sb->fs_fsbtodb;
-       asb->fs_interleave = sb->fs_interleave;
-       asb->fs_npsect = sb->fs_npsect;
-       asb->fs_nrpos = sb->fs_nrpos;
-       asb->fs_qbmask = sb->fs_qbmask;
-       asb->fs_qfmask = sb->fs_qfmask;
-       asb->fs_state = sb->fs_state;
-       asb->fs_maxfilesize = sb->fs_maxfilesize;
+       if (asb->fs_sblkno != sb->fs_sblkno ||
+           asb->fs_cblkno != sb->fs_cblkno ||
+           asb->fs_iblkno != sb->fs_iblkno ||
+           asb->fs_dblkno != sb->fs_dblkno ||
+           asb->fs_cgoffset != sb->fs_cgoffset ||
+           asb->fs_cgmask != sb->fs_cgmask ||
+           asb->fs_ncg != sb->fs_ncg ||
+           asb->fs_bsize != sb->fs_bsize ||
+           asb->fs_fsize != sb->fs_fsize ||
+           asb->fs_frag != sb->fs_frag ||
+           asb->fs_bmask != sb->fs_bmask ||
+           asb->fs_fmask != sb->fs_fmask ||
+           asb->fs_bshift != sb->fs_bshift ||
+           asb->fs_fshift != sb->fs_fshift ||
+           asb->fs_fragshift != sb->fs_fragshift ||
+           asb->fs_fsbtodb != sb->fs_fsbtodb ||
+           asb->fs_sbsize != sb->fs_sbsize ||
+           asb->fs_nindir != sb->fs_nindir ||
+           asb->fs_inopb != sb->fs_inopb ||
+           asb->fs_cssize != sb->fs_cssize ||
+           asb->fs_cpg != sb->fs_cpg ||
+           asb->fs_ipg != sb->fs_ipg ||
+           asb->fs_fpg != sb->fs_fpg ||
+           asb->fs_magic != sb->fs_magic)
+               return (1);
 
-       /*
-        * Compare the superblocks, effectively checking every other
-        * field to see if they differ.
-        */
-       return (memcmp(sb, asb, (int)sb->fs_sbsize));
+       return (0);
 }
 
 static void