[src/trunk]: src/sbin/tunefs add -S option to adjust the superblock for diffe...

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

details:   https://anonhg.NetBSD.org/src/rev/35c8b1ee419e
branches:  trunk
changeset: 331357:35c8b1ee419e
user:      mlelstv <mlelstv%NetBSD.org@localhost>
date:      Sat Aug 09 10:33:46 2014 +0000

description:
add -S option to adjust the superblock for different sector sizes. While
the kernel ignores this information, userland tools rely on it.

This is needed when moving images between devices of different sector size.

diffstat:

 sbin/tunefs/tunefs.8 |  15 ++++++++++++++-
 sbin/tunefs/tunefs.c |  50 +++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 59 insertions(+), 6 deletions(-)

diffs (145 lines):

diff -r 693f08d17581 -r 35c8b1ee419e sbin/tunefs/tunefs.8
--- a/sbin/tunefs/tunefs.8      Sat Aug 09 09:47:02 2014 +0000
+++ b/sbin/tunefs/tunefs.8      Sat Aug 09 10:33:46 2014 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: tunefs.8,v 1.42 2012/12/03 12:28:06 wiz Exp $
+.\"    $NetBSD: tunefs.8,v 1.43 2014/08/09 10:33:46 mlelstv Exp $
 .\"
 .\" Copyright (c) 1983, 1991, 1993
 .\"    The Regents of the University of California.  All rights reserved.
@@ -45,6 +45,7 @@
 .Op Fl m Ar minfree
 .Op Fl o Ar optimize_preference
 .Op Fl q Ar quota
+.Op Fl S Ar sectorsize
 .Ar special | Ar filesys
 .Sh DESCRIPTION
 .Nm
@@ -152,6 +153,18 @@
 After enabling a quota,
 .Xr fsck_ffs 8
 has to be run to compute the correct quota values.
+.Pp
+.It Fl S Ar sectorsize
+changes the fsbtodb value in the superblock to reflect a particular
+physical sector size. This value is ignored by the NetBSD kernel but
+needed by tools like
+.Xr fsck_ffs  8
+to access disk blocks correctly. The minimum value is DEV_BSIZE (512).
+.Pp
+Changing the fsbtodb value becomes necessary when a filesystem image
+is created for one sector size and then transferred to a device with
+a different sector size and should be applied also to the alternate
+superblocks.
 .El
 .Sh SEE ALSO
 .Xr wapbl 4 ,
diff -r 693f08d17581 -r 35c8b1ee419e sbin/tunefs/tunefs.c
--- a/sbin/tunefs/tunefs.c      Sat Aug 09 09:47:02 2014 +0000
+++ b/sbin/tunefs/tunefs.c      Sat Aug 09 10:33:46 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tunefs.c,v 1.47 2014/04/26 13:23:49 martin Exp $       */
+/*     $NetBSD: tunefs.c,v 1.48 2014/08/09 10:33:46 mlelstv Exp $      */
 
 /*
  * Copyright (c) 1983, 1993
@@ -39,7 +39,7 @@
 #if 0
 static char sccsid[] = "@(#)tunefs.c   8.3 (Berkeley) 5/3/95";
 #else
-__RCSID("$NetBSD: tunefs.c,v 1.47 2014/04/26 13:23:49 martin Exp $");
+__RCSID("$NetBSD: tunefs.c,v 1.48 2014/08/09 10:33:46 mlelstv Exp $");
 #endif
 #endif /* not lint */
 
@@ -102,18 +102,20 @@
        int             i, ch, Aflag, Fflag, Nflag, openflags;
        const char      *special, *chg[2];
        char            device[MAXPATHLEN];
-       int             maxbpg, minfree, optim;
+       int             maxbpg, minfree, optim, secsize;
        int             avgfilesize, avgfpdir;
        long long       logfilesize;
+       int             secshift, fsbtodb;
 
        Aflag = Fflag = Nflag = 0;
-       maxbpg = minfree = optim = -1;
+       maxbpg = minfree = optim = secsize = -1;
        avgfilesize = avgfpdir = -1;
        logfilesize = -1;
+       secshift = 0;
        chg[FS_OPTSPACE] = "space";
        chg[FS_OPTTIME] = "time";
 
-       while ((ch = getopt(argc, argv, "AFNe:g:h:l:m:o:q:")) != -1) {
+       while ((ch = getopt(argc, argv, "AFNe:g:h:l:m:o:q:S:")) != -1) {
                switch (ch) {
 
                case 'A':
@@ -177,6 +179,13 @@
                        else
                            errx(11, "invalid quota type %s", optarg);
                        break;
+               case 'S':
+                       secsize = strsuftoll("physical sector size",
+                           optarg, 0, INT_MAX);
+                       secshift = ffs(secsize) - 1;
+                       if (secsize != 0 && 1 << secshift != secsize)
+                               errx(12, "sector size %d is not a power of two", secsize);
+                       break;
                default:
                        usage();
                }
@@ -241,6 +250,30 @@
                                warnx(OPTWARN, "space", "<", MINFREE);
                }
        }
+       if (secsize != -1) {
+               if (secsize == 0) {
+                       secsize = sblock.fs_fsize / FFS_FSBTODB(&sblock, 1);
+                       secshift = ffs(secsize) - 1;
+               }
+
+               if (secshift < DEV_BSHIFT)
+                       warnx("sector size must be at least %d", DEV_BSIZE);
+               else if (secshift > sblock.fs_fshift)
+                       warnx("sector size %d cannot be larger than fragment size %d",
+                               secsize, sblock.fs_fsize);
+               else {
+                       fsbtodb = sblock.fs_fshift - secshift;
+                       if (fsbtodb == sblock.fs_fsbtodb) {
+                               warnx("sector size remains unchanged as %d",
+                                       sblock.fs_fsize / FFS_FSBTODB(&sblock, 1));
+                       } else {
+                               warnx("sector size changed from %d to %d",
+                                       sblock.fs_fsize / FFS_FSBTODB(&sblock, 1),
+                                       secsize);
+                               sblock.fs_fsbtodb = fsbtodb;
+                       }
+               }
+       }
        CHANGEVAL(sblock.fs_avgfilesize, avgfilesize,
            "average file size", "");
        CHANGEVAL(sblock.fs_avgfpdir, avgfpdir,
@@ -328,7 +361,13 @@
        memcpy(&buf, (char *)&sblock, SBLOCKSIZE);
        if (needswap)
                ffs_sb_swap((struct fs*)&buf, (struct fs*)&buf);
+
+       /* write superblock to original coordinates (use old dev_bsize!) */
        bwrite(sblockloc, buf.data, SBLOCKSIZE, special);
+
+       /* correct dev_bsize from possibly changed superblock data */
+       dev_bsize = sblock.fs_fsize / FFS_FSBTODB(&sblock, 1);
+
        if (Aflag)
                for (i = 0; i < sblock.fs_ncg; i++)
                        bwrite(FFS_FSBTODB(&sblock, cgsblock(&sblock, i)),
@@ -479,6 +518,7 @@
        fprintf(stderr, "\t-m minimum percentage of free space\n");
        fprintf(stderr, "\t-o optimization preference (`space' or `time')\n");
        fprintf(stderr, "\t-q quota type (`[no]user' or `[no]group')\n");
+       fprintf(stderr, "\t-S sector size\n");
        exit(2);
 }