freebsd-src/sys
Kirk McKusick e688661642 Move the ability to search for alternate UFS superblocks from fsck_ffs(8)
into ffs_sbsearch() to allow use by other parts of the system.

Historically only fsck_ffs(8), the UFS filesystem checker, had code
to track down and use alternate UFS superblocks. Since fsdb(8) used
much of the fsck_ffs(8) implementation it had some ability to track
down alternate superblocks.

This change extracts the code to track down alternate superblocks
from fsck_ffs(8) and puts it into a new function ffs_sbsearch() in
sys/ufs/ffs/ffs_subr.c. Like ffs_sbget() and ffs_sbput() also found
in ffs_subr.c, these functions can be used directly by the kernel
subsystems. Additionally they are exported to the UFS library,
libufs(8) so that they can be used by user-level programs. The new
functions added to libufs(8) are sbfind(3) that is an alternative
to sbread(3) and sbsearch(3) that is an alternative to sbget(3).
See their manual pages for further details.

The utilities that have been changed to search for superblocks are
dumpfs(8), fsdb(8), ffsinfo(8), and fsck_ffs(8). Also, the prtblknos(8)
tool found in tools/diag/prtblknos searches for superblocks.

The UFS specific mount code uses the superblock search interface
when mounting the root filesystem and when the administrator doing
a mount(8) command specifies the force flag (-f). The standalone UFS
boot code (found in stand/libsa/ufs.c) uses the superblock search
code in the hope of being able to get the system up and running so
that fsck_ffs(8) can be used to get the filesystem cleaned up.

The following utilities have not been changed to search for
superblocks: clri(8), tunefs(8), snapinfo(8), fstyp(8), quot(8),
dump(8), fsirand(8), growfs(8), quotacheck(8), gjournal(8), and
glabel(8). When these utilities fail, they do report the cause of
the failure. The one exception is the tasting code used to try and
figure what a given disk contains. The tasting code will remain
silent so as not to put out a slew of messages as it trying to taste
every new mass storage device that shows up.

Reviewed by: kib
Reviewed by: Warner Losh
Tested by:   Peter Holm
Differential Revision: https://reviews.freebsd.org/D36053
Sponsored by: The FreeBSD Foundation
2022-08-13 12:43:40 -07:00
..
amd64 Document implicit dependencies of the mlx5(4) & friends. 2022-08-11 16:33:09 -07:00
arm
arm64
bsm
cam
cddl
compat
conf
contrib stand: Only compile decompression routines 2022-08-12 21:48:18 -06:00
crypto
ddb
dev
dts
fs
gdb
geom
gnu
i386
isa
kern protosw: change prototype for pr_control 2022-08-12 12:08:18 -07:00
kgssapi
libkern
modules mrsas module: Use MACHINE_ARCH exlcusively 2022-08-13 11:56:53 -06:00
net routing: add rib_match_gw() helper 2022-08-12 09:31:21 +00:00
net80211
netgraph protosw: change prototype for pr_control 2022-08-12 12:08:18 -07:00
netinet protosw: change prototype for pr_control 2022-08-12 12:08:18 -07:00
netinet6 protosw: change prototype for pr_control 2022-08-12 12:08:18 -07:00
netipsec keysock: explicitly initialized LIST_HEAD 2022-08-12 12:29:26 -07:00
netpfil
netsmb
nfs
nfsclient
nfsserver
nlm
ofed protosw: change prototype for pr_control 2022-08-12 12:08:18 -07:00
opencrypto
powerpc
riscv
rpc
security mac_ddb: Fix the show rman validator. 2022-08-12 10:20:05 -07:00
sys protosw: change prototype for pr_control 2022-08-12 12:08:18 -07:00
teken
tests
tools
ufs Move the ability to search for alternate UFS superblocks from fsck_ffs(8) 2022-08-13 12:43:40 -07:00
vm sys/vm: Add TSLOG to some functions 2022-08-12 16:53:04 -07:00
x86
xdr
xen
Makefile