From 24cedfbba2cbb0005bb4731b8554409ad38baefa Mon Sep 17 00:00:00 2001
From: dsl <dsl@NetBSD.org>
Date: Sun, 25 Apr 2004 17:15:27 +0000
Subject: [PATCH] Merge in code from my version of Darrin's fixsb routine (we
 both wrote much the same function). Mainly some extra comments, also moved a
 'static' so we use 512bytes of stack and not static data.  Killed call to
 access() as it is pointless and doesn't do what you want (access is for suid
 programs to check whether the real user could do the operation).

---
 distrib/utils/sysinst/disks.c | 39 +++++++++++++++++++++++++++--------
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/distrib/utils/sysinst/disks.c b/distrib/utils/sysinst/disks.c
index 8e5ccda2533e..9acb51b477ac 100644
--- a/distrib/utils/sysinst/disks.c
+++ b/distrib/utils/sysinst/disks.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: disks.c,v 1.80 2004/04/24 20:54:26 dbj Exp $ */
+/*	$NetBSD: disks.c,v 1.81 2004/04/25 17:15:27 dsl Exp $ */
 
 /*
  * Copyright 1997 Piermont Information Systems Inc.
@@ -505,7 +505,7 @@ foundffs(struct data *list, size_t num)
 }
 
 /*
- * Do an fsck. On failure,  inform the user by showing a warning
+ * Do an fsck. On failure, inform the user by showing a warning
  * message and doing menu_ok() before proceeding.
  * Returns 0 on success, or nonzero return code from fsck() on failure.
  */
@@ -531,28 +531,41 @@ fsck_preen(const char *disk, int ptn, const char *fsname)
 	if (error != 0) {
 		msg_display(MSG_badfs, disk, ptn, error);
 		process_menu(MENU_ok, NULL);
+		/* XXX at this point maybe we should run a full fsck? */
 	}
 	return error;
 }
 
-/* This performs the same function as the etc/rc.d/fixsb script.
- * see NetBSD pr install/25138 for details. */
+/*
+ * The import of FFSv2 was rather botched and many 1.6 'current' kernels
+ * modified the superblock into a state part way between the 'old' format
+ * and what an 'updated' superblock would have to look like.
+ * This code attempts to detect, fix and reverse the error.
+ * 1.6.1, 1.6.2 and the 2.0 release contain 'good' kernels...
+ * This performs the same function as the etc/rc.d/fixsb script.
+ * see NetBSD pr install/25138 for details.
+ * (There are also problems with filesystems with 64k block size, which
+ * fsck should fix itself.)
+ */
+
 static void
 fixsb(const char *disk, int ptn)
 {
 	int fd;
 	char diskpath[MAXPATHLEN];
-	char *prog = "/sbin/fsck_ffs";
+	static char prog[] = "/sbin/fsck_ffs";
 	int rval;
-	static uint64_t sblk[SBLOCKSIZE/sizeof(uint64_t)];
+	uint64_t sblk[SBLOCKSIZE/sizeof(uint64_t)];
 	struct fs *fs = (struct fs *)sblk;
 	char *part;
 
-	asprintf(&part, "%s%c",disk,ptn+'a');
+	asprintf(&part, "%s%c", disk, ptn + 'a');
 	fd = opendisk(part, O_RDONLY, diskpath, sizeof(diskpath), 0);
 	free(part);
 	if (fd == -1)
 		return;
+
+	/* Read ffsv1 main superblock */
 	rval = pread(fd, sblk, sizeof sblk, SBLOCK_UFS1);
 	close(fd);
 	if (rval != sizeof sblk)
@@ -560,15 +573,23 @@ fixsb(const char *disk, int ptn)
 
 	if (fs->fs_magic != FS_UFS1_MAGIC &&
 	    fs->fs_magic != FS_UFS1_MAGIC_SWAPPED)
+		/* Not FFSv1 */
 		return;
 	if (fs->fs_old_flags & FS_FLAGS_UPDATED)
+		/* properly updated fslevel 4 */
 		return;
 	if (fs->fs_bsize != fs->fs_maxbsize)
+		/* not messed up */
 		return;
 
-	if (access(prog, X_OK) != 0)
+	/*
+	 * OK we have a munged fs, first 'upgrade' to fslevel 4,
+	 * We specify -b16 in order to stop fsck bleating that the
+	 * sb doesn't match the first alternate.
+	 */
+	if (run_program(0, "%s -p -q -b 16 -c 4 %s", prog, diskpath) != 0)
 		return;
-	run_program(0, "%s -p -q -b 16 -c 4 %s", prog, diskpath);
+	/* Then downgrade to fslevel 3 */
 	run_program(0, "%s -p -q -c 3 %s", prog, diskpath);
 }