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When newfs'ing a partition with UFS2 that had previously been newfs'ed

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with UFS1, the UFS1 superblocks were not deleted. This allowed any
RELENG_4 (or other non-UFS2-aware) fsck to think it knew how to "fix"
the file system, resulting in severe data scrambling.

This patch is a more advanced version than the one originally submitted.
Lukas improved it based on feedback from Kirk, and testing by me. It
blanks all UFS1 superblocks (if any) during a UFS2 newfs, thereby causing
fsck's that are not UFS2 aware to generate the "SEARCH FOR ALTERNATE
SUPER-BLOCK FAILED" message, and exit without damaging the fs.

PR:		bin/51619
Submitted by:	Lukas Ertl <l.ertl@univie.ac.at>
Reviewed by:	kirk
Approved by:	re (scottl)
This commit is contained in:
Doug Barton 2003-05-22 18:38:54 +00:00
parent cdc95e1bb8
commit a32bb1b53a
1 changed files with 24 additions and 0 deletions

24
sbin/newfs/mkfs.c

@ -113,6 +113,12 @@ mkfs(struct partition *pp, char *fsys)
quad_t sizepb;
int width;
char tmpbuf[100]; /* XXX this will break in about 2,500 years */
union {
struct fs fdummy;
char cdummy[SBLOCKSIZE];
} dummy;
#define fsdummy dummy.fdummy
#define chdummy dummy.cdummy
/*
* Our blocks == sector size, and the version of UFS we are using is
@ -425,6 +431,24 @@ mkfs(struct partition *pp, char *fsys)
if (sblock.fs_flags & FS_DOSOFTDEP)
printf("\twith soft updates\n");
# undef B2MBFACTOR
/*
* Wipe out old UFS1 superblock(s) if necessary.
*/
if (!Nflag && Oflag != 1) {
i = bread(&disk, SBLOCK_UFS1 / disk.d_bsize, chdummy, SBLOCKSIZE);
if (i == -1)
err(1, "can't read old UFS1 superblock: %s", disk.d_error);
if (fsdummy.fs_magic == FS_UFS1_MAGIC) {
fsdummy.fs_magic = 0;
bwrite(&disk, SBLOCK_UFS1 / disk.d_bsize, chdummy, SBLOCKSIZE);
for (i = 0; i < fsdummy.fs_ncg; i++)
bwrite(&disk, fsbtodb(&fsdummy, cgsblock(&fsdummy, i)),
chdummy, SBLOCKSIZE);
}
}
/*
* Now build the cylinders group blocks and
* then print out indices of cylinder groups.