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Delete UFS2 backup superblock recovery info when building a UFS1 filesystem.

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Only the UFS2 filesystem has support for storing information needed
to find alternate superblocks. If that information is inadvertently
left in place when building a UFS1 filesystem, fsck_ffs may stumble
across it and attempt to use it to recover the UFS1 filesystem
which can only end poorly.
This commit is contained in:
Kirk McKusick 2022-07-20 22:45:18 -07:00
parent 7c332e97bb
commit f030f1102c
1 changed files with 13 additions and 10 deletions
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23
sbin/newfs/mkfs.c
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@ -636,23 +636,26 @@ mkfs(struct partition *pp, char *fsys)
* Read the last sector of the boot block, replace the last
* 20 bytes with the recovery information, then write it back.
* The recovery information only works for UFS2 filesystems.
* For UFS1, zero out the area to ensure that an old UFS2
* recovery block is not accidentally found.
*/
if (sblock.fs_magic == FS_UFS2_MAGIC) {
if ((fsrbuf = malloc(realsectorsize)) == NULL || bread(&disk,
part_ofs + (SBLOCK_UFS2 - realsectorsize) / disk.d_bsize,
fsrbuf, realsectorsize) == -1)
err(1, "can't read recovery area: %s", disk.d_error);
fsr =
(struct fsrecovery *)&fsrbuf[realsectorsize - sizeof *fsr];
if ((fsrbuf = malloc(realsectorsize)) == NULL || bread(&disk,
part_ofs + (SBLOCK_UFS2 - realsectorsize) / disk.d_bsize,
fsrbuf, realsectorsize) == -1)
err(1, "can't read recovery area: %s", disk.d_error);
fsr = (struct fsrecovery *)&fsrbuf[realsectorsize - sizeof *fsr];
if (sblock.fs_magic != FS_UFS2_MAGIC) {
memset(fsr, 0, sizeof *fsr);
} else {
fsr->fsr_magic = sblock.fs_magic;
fsr->fsr_fpg = sblock.fs_fpg;
fsr->fsr_fsbtodb = sblock.fs_fsbtodb;
fsr->fsr_sblkno = sblock.fs_sblkno;
fsr->fsr_ncg = sblock.fs_ncg;
wtfs((SBLOCK_UFS2 - realsectorsize) / disk.d_bsize,
realsectorsize, fsrbuf);
free(fsrbuf);
}
wtfs((SBLOCK_UFS2 - realsectorsize) / disk.d_bsize,
realsectorsize, fsrbuf);
free(fsrbuf);
/*
* Update information about this partition in pack
* label, to that it may be updated on disk.