The kernel handles the managment of UFS/FFS snapshots. Since UFS/FFS
updates filesystem data (rather than always writing changes to new
locations like ZFS), the kernel must check every filesystem write
to see if the block being written is part of a snapshot. If it is
part of a snapshot, then the kernel must make a copy of the old
block value into a newly allocated block for the snapshot before
allowing the write to be done. Similarly, if a block is being freed,
the kernel must check to see if it is part of a snapshot and let
the snapshot claim the block rather than freeing it for future use.
When a snapshot is freed, its blocks need to be offered to older
snapshots and freed only if no older snapshots wish to claim them.
When snapshots were added to UFS/FFS they were integrated into soft
updates and just a small part of the management of snapshots needed
to be added to fsck_ffs(8) as soft updates minimized the set of
snapshot changes that might need correction. When journaling was
added to soft updates a much more complete knowledge of snapshots
needed to be added to fsck_ffs(8) for it to be able to properly
handle the filesystem changes that a journal rollback needs to do
(specifically the freeing and allocation of blocks). Since this
functionality was unavailable, the use of snapshots was disabled
when running with journaled soft updates.
This set of changes imports the kernel code for the management of
snapshots to fsck_ffs(8). With this code in place it will become
possible to enable snapshots when running with journalled soft
updates. The most immediate benefit will be the ability to use
snapshots to take consistent filesystem dumps on live filesystems.
Future work will be done to update fsck_ffs(8) to be able to use
snapshots to run in background on live filesystems running with
journaled soft updates.
Reviewed by: kib
Tested by: Peter Holm
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D36491
When either searching for backup UFS superblocks or when explicitly asked
to use one with the -b option, report the reason for failure if it cannot
be used.
Reported by: Peter Holm
Sponsored by: The FreeBSD Foundation
Allocation or I/O failures in fsck_ffs(8) could cause segment
faults because of missing checks or not-yet-initialized data
structures. Correct these issues.
Reported by: Peter Holm
Sponsored by: The FreeBSD Foundation
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
The fsck_ffs(8) utility made sanity checks of critical superblock
fields by comparing the values of those fields in the standard
superblock againt the values of those fields in the last alternate
superblock. The code for validating a superblock now cover all the
checked fields as well as many more. Further the checks done are
far more comprehensive. So we now drop the alternate superblock
checks as they no longer provide value. Dropping these checks also
eliminates the need to read the alternate superblock.
Rather than trying to shoehorn flags into the requested superblock
address, create a separate flags parameter to the ffs_sbget()
function in sys/ufs/ffs/ffs_subr.c. The ffs_sbget() function is
used both in the kernel and in user-level utilities through export
to the sbget() function in the libufs(3) library (see sbget(3)
for details). The kernel uses ffs_sbget() when mounting UFS
filesystems, in the glabel(8) and gjournal(8) GEOM utilities,
and in the standalone library used when booting the system
from a UFS root filesystem.
The ffs_sbget() function reads the superblock located at the byte
offset specified by its sblockloc parameter. The value UFS_STDSB
may be specified for sblockloc to request that the standard
location for the superblock be read.
The two existing options are now flags:
UFS_NOHASHFAIL will note if the check hash is wrong but will still
return the superblock. This is used by the bootstrap code to
give the system a chance to come up so that fsck can be run to
correct the problem.
UFS_NOMSG indicates that superblock inconsistency error messages
should not be printed. It is used by programs like fsck that
want to print their own error message and programs like glabel(8)
that just want to know if a UFS filesystem exists on a partition.
One additional flag is added:
UFS_NOCSUM causes only the superblock itself to be returned, but does
not read in any auxiliary data structures like the cylinder group
summary information. It is used by clients like glabel(8) that
just want to check for possible filesystem types. Using UFS_NOCSUM
skips the superblock checks for csum data which allows superblocks
that have corrupted csum data to be read and used.
The validate_sblock() function checks that the superblock has not
been corrupted in a way that can crash or hang the system. Unless
the UFS_NOMSG flag is specified, it will print out any errors that
it finds. Prior to this commit, validate_sblock() returned as soon
as it found an inconsistency so would print at most one message.
It now does all its checks so when UFS_NOMSG has not been specified
will print out everything that it finds inconsistent.
Sponsored by: The FreeBSD Foundation
for missing devices.
The fsck_ffs(8) utility uses its internal function openfilesys()
when opening a disk to be checked. This change avoids the use
of pfatal() in openfilesys() which always exits with failure (exit
value 8) so that the caller can choose the correct exit value.
In the case of a non-existent device it should exit with value 3
which allows the startup system to wait for drives (such as those
attached by USB) to come online.
Reported by: karels
Tested by: karels
PR: 262580
MFC after: 3 days
The cleanup of fsck_ffs(8) in commit c0bfa109b9 broke fsdb(8).
This commit adds the one-line update needed in fsdb(8) to make it
work with the new fsck_ffs(8) structure.
Reported by: Chuck Silvers
Tested by: Chuck Silvers
MFC after: 3 days
Normally fsck_ffs never does reads or writes that are not aligned
to the size of one of the checked filesystems fragments. The one
exception is when it finds that it needs to write the superblock
recovery information. Here it will write with the alignment reported
by the underlying disk as its sector size as reported by an
ioctl(diskfd, DIOCGSECTORSIZE, &secsize).
Modern disks have a sector size of 4096, but for backward compatibility
with older disks will report that they have a sector size of 512.
When presented with a 512 byte write, they have to read the associated
4096 byte sector, replace the 512 bytes to be written, and write
the updated 4096 byte sector back to the disk. Unfortunately, some
disks report that they have 512 sectors, but fail writes that are not
aligned to 4096 boundaries and are a multiple of 4096 bytes in size.
This commit updates fsck_ffs(8) so that it uses the filesystem fragment
size as the smallest size and alignment for doing writes rather than
the disk's reported sector size.
Reported by: Andriy Gapon
MFC after: 1 week
Part of the problem was that fsck_ffs would read the superblock
multiple times complaining and repairing the superblock check hash
each time and then at the end failing to write out the superblock
with the corrected check hash. This fix reads the superblock just
once and if the check hash is corrected ensures that the fixed
superblock gets written.
Tested by: Peter Holm
PR: 245916
MFC after: 1 week
Sponsored by: Netflix
The segfault was being hit in ckfini() (sbin/fsck_ffs/fsutil.c)
while attempting to traverse the buffer cache to flush dirty buffers.
The tail queue used for the buffer cache was not initialized before
dropping into gjournal_check(). Move the buffer initialization earlier
so that it has been done before calling gjournal_check().
Reported by: crypt47, nvass
Fix by: Robert Wing
Tested by: Robert Wing
PR: 255030
PR: 255979
MFC after: 3 days
Sponsored by: Netflix
making fsck_ffs(8) run faster, there should be no functional change.
The original fsck_ffs(8) had its own disk I/O management system.
When gjournal(8) was added to FreeBSD 7, code was added to fsck_ffs(8)
to do the necessary gjournal rollback. Rather than use the existing
fsck_ffs(8) disk I/O system, it wrote its own from scratch. Similarly
when journalled soft updates were added in FreeBSD 9, code was added
to fsck_ffs(8) to do the necessary journal rollback. And once again,
rather than using either of the existing fsck_ffs(8) disk I/O
systems, it wrote its own from scratch. Lastly the fsdb(8) utility
uses the fsck_ffs(8) disk I/O management system. In preparation for
making the changes necessary to enable snapshots to be taken when
using journalled soft updates, it was necessary to have a single
disk I/O system used by all the various subsystems in fsck_ffs(8).
This commit merges the functionality required by all the different
subsystems into a single disk I/O system that supports all of their
needs. In so doing it picks up optimizations from each of them
with the results that each of the subsystems does fewer reads and
writes than it did with its own customized I/O system. It also
greatly simplifies making changes to fsck_ffs(8) since everything
goes through a single place. For example the ginode() function
fetches an inode from the disk. When inode check hashes were added,
they previously had to be checked in the code implementing inode
fetch in each of the three different disk I/O systems. Now they
need only be checked in ginode().
Tested by: Peter Holm
Sponsored by: Netflix
over various major releases. Superblock check hashes were added for
the 12 release and cylinder-group and inode check hashes will appear
in the 13 release.
When a disk with a UFS filesystem is writably mounted, the kernel
clears the feature flags for anything that it does not support. For
example, if a UFS disk from a 12-stable kernel is mounted on an
11-stable system, the 11-stable kernel will clear the flag in the
filesystem superblock that indicates that superblock check-hashs
are being maintained. Thus if the disk is later moved back to a
12-stable system, the 12-stable system will know to ignore its
incorrect check-hash.
If the only filesystem modification done on the earlier kernel is
to run a utility such as growfs(8) that modifies the superblock but
neither updates the check-hash nor clears the feature flag indicating
that it does not support the check-hash, the disk will fail to mount
if it is moved back to its original newer kernel.
This patch moves the code that clears the filesystem feature flags
from the mount code (ffs_mountfs()) to the code that reads the
superblock (ffs_sbget()). As ffs_sbget() is used by the kernel mount
code and is imported into libufs(3), all the filesystem utilities
will now also clear these flags when they make modifications to the
filesystem.
As suggested by John Baldwin, fsck_ffs(8) has been changed to accept
and repair bad superblock check-hashes rather than refusing to run.
This change allows fsck to recover filesystems that have been impacted
by utilities older than those created after this change and is a
sensible thing to do in any event.
Reported by: John Baldwin (jhb@)
MFC after: 2 weeks
Sponsored by: Netflix
The only output from fsck that should go to stderr is the usage message.
if setup() fails then exit with EEXIT rather than 0.
Reviewed by: mckusick
Sponsored by: Netflix
This one is also a small list:
- 3x duplicate definition (ufs2_zino, returntosingle, nflag)
- 5x 'needs extern', 3/5 of which are referenced in fsdb
-fno-common will become the default in GCC10/LLVM11.
MFC after: 1 week
shorter than its size resulting in a hole as its final block (which
is a violation of the invarients of the UFS filesystem).
Soft updates will always ensure that the file size is correct when
writing inodes to disk for files that contain only direct block
pointers. However soft updates does not roll back sizes for files
with indirect blocks that it has set to unallocated because their
contents have not yet been written to disk. Hence, the file can
appear to have a hole at its end because the block pointer has been
rolled back to zero when its inode was written to disk. Thus,
fsck_ffs calculates the last allocated block in the file. For files
that extend into indirect blocks, fsck_ffs checks for a size past
the last allocated block of the file and if that is found, shortens
the file to reference the last allocated block thus avoiding having
it reference a hole at its end.
Submitted by: Chuck Silvers <chs@netflix.com>
Tested by: Chuck Silvers <chs@netflix.com>
MFC after: 1 week
Sponsored by: Netflix
superblock has a check-hash error, an error message noting the
superblock check-hash failure is printed and the mount fails. The
administrator then runs fsck to repair the filesystem and when
successful, the filesystem can once again be mounted.
This approach fails if the filesystem in question is a root filesystem
from which you are trying to boot. Here, the loader fails when trying
to access the filesystem to get the kernel to boot. So it is necessary
to allow the loader to ignore the superblock check-hash error and make
a best effort to read the kernel. The filesystem may be suffiently
corrupted that the read attempt fails, but there is no harm in trying
since the loader makes no attempt to write to the filesystem.
Once the kernel is loaded and starts to run, it attempts to mount its
root filesystem. Once again, failure means that it breaks to its prompt
to ask where to get its root filesystem. Unless you have an alternate
root filesystem, you are stuck.
Since the root filesystem is initially mounted read-only, it is
safe to make an attempt to mount the root filesystem with the failed
superblock check-hash. Thus, when asked to mount a root filesystem
with a failed superblock check-hash, the kernel prints a warning
message that the root filesystem superblock check-hash needs repair,
but notes that it is ignoring the error and proceeding. It does
mark the filesystem as needing an fsck which prevents it from being
enabled for writing until fsck has been run on it. The net effect
is that the reboot fails to single user, but at least at that point
the administrator has the tools at hand to fix the problem.
Reported by: Rick Macklem (rmacklem@)
Discussed with: Warner Losh (imp@)
Sponsored by: Netflix
report the check-hash failure and offer to search for and use
alternate superblocks. Prior to this fix fsck_ffs would simply
report the check-hash failure and exit.
Reported by: Julian H. Stacey <jhs@berklix.com>
Tested by: Peter Holm
Sponsored by: Netflix
Specifically reading is done if ffs_sbget() and writing is done
in ffs_sbput(). These functions are exported to libufs via the
sbget() and sbput() functions which then used in the various
filesystem utilities. This work is in preparation for adding
subperblock check hashes.
No functional change intended.
Reviewed by: kib
routine to write out the cylinder groups rather than recreating the
calculation of the cylinder-group check hash in fsck_ffs.
No functional change intended.
Mainly focus on files that use BSD 3-Clause license.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
superblocks created in revision 322297 only works on disks
with sector sizes up to 4K. This update allows the recovery
information to be created by newfs and used by fsck on disks
with sector sizes up to 64K. Note that FFS currently limits
filesystem to be mounted from disks with up to 8K sectors.
Expanding this limitation will be the subject of another
commit.
Reported by: Peter Holm
Reviewed with: kib
unable to automatically find alternate superblocks. This checkin
places the information needed to find alternate superblocks to the
end of the area reserved for the boot block.
Filesystems created with a newfs of this vintage or later will
create the recovery information. If you have a filesystem created
prior to this change and wish to have a recovery block created for
your filesystem, you can do so by running fsck in forground mode
(i.e., do not use the -p or -y options). As it starts, fsck will
ask ``SAVE DATA TO FIND ALTERNATE SUPERBLOCKS'' to which you should
answer yes.
Discussed with: kib, imp
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D11589
a mismatch, but will allow fsck to continue when the last alternate
superblock gets corrupted somehow.
Also, remove searching for alternate super blocks. It should have been
removed two years ago with r276737 by imp@. Leave minor vestiges in
place in case someone wants to solve the hard problem of knowing where
altnernate superblocks live without access to data formerly stored in
disklabels.
Differential Revision: https://reviews.freebsd.org/D11589
Instead of casting listmax and numdirs to unsigned values just define
them as unsigned and avoid the casts. Use reallocarray(3).
While here, fs_ncg is already unsigned so the cast is unnecessary.
Reviewed by: mckusick
MFC after: 2 weeks
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.
Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96
alternate superblock location when given in the -b option. When int
is 32-bits, block numbers larger than 2^32 would get truncated. This
commit changes the storage fpr the alternate superblock location
to a ufs2_daddr_t.
Submitted by: Dmitry Sivachenko <trtrmitya@gmail.com>
Clang errors around printf could be trivially fixed, but the breakage in
sbin/fsdb were to significant for this type of change.
Submitter of this changeset has been notified and hopefully this can be
restored soon.
that they do not need to be read again in pass5. As this nearly
doubles the memory requirement for fsck, the cache is thrown away
if other memory needs in fsck would otherwise fail. Thus, the
memory footprint of fsck remains unchanged in memory constrained
environments.
This work was inspired by a paper presented at Usenix's FAST '13:
www.usenix.org/conference/fast13/ffsck-fast-file-system-checker
Details of this implementation appears in the April 2013 of ;login:
www.usenix.org/publications/login/april-2013-volume-38-number-2.
A copy of the April 2013 ;login: paper can also be downloaded
from: www.mckusick.com/publications/faster_fsck.pdf.
Reviewed by: kib
Tested by: Peter Holm
MFC after: 4 weeks
Due to UFS insistence to pretend that device sector size is 512 bytes,
sector size is obtained from ioctl(DIOCGSECTORSIZE) for real devices,
and from the label otherwise. The file images without label have to
be made with 512 sector size.
In collaboration with: pho
Reviewed by: jeff
Tested by: bz, pho
whether fs_bsize is larger than MINBSIZE, which is larger than the
value that is used to compared with fs_bsize, the sizeof fs, so the
check followed, will be always true.
By inspecting the code and some old commit log, I believe that the
check must be that *fs_sbsize* is larger than sizeof fs. We round
up the size to nearest dev_bsize, as the smallest accepted fs_sbsize,
personally, I think this can be even changed to equal, because this
number is mostly an invariant in file systems.
With this check, fsck_ffs(8) will be more picky and has better
chance rejecting bad first superblock rather than referring to bad
value it supplied, thus gives better chance for it to check the
filesystem carefully.
and -p flag was given perform fast file system checking (bascially only
garbage collecting of orphaned objects).
Rename bread() to blread() and bwrite() to blwrite() as we now link to
the libufs library, which also implement functions with that names.
Sponsored by: home.pl
initializing the sysctl mibs data before actually using them.
The original patchset (which is the actual version that is running
on my testboxes) have checked whether all of these sysctls and
refuses to do background fsck if we don't have them. Kirk has
pointed out that refusing running fsck on old kernels is pointless,
as old kernels will recompute the summary at mount time, so I
have removed these checks.
Unfortunatelly, as the checks will initialize the mib values of
those sysctl's, and which are vital for the runtime summary
adjustment to work, we can not simply remove the check, which
will lead to problem when running background fsck over a dirty
volume. Add these checks in a different way: give a warning rather
than refusing to work, and complain if the functionality is not
available when adjustments are necessary.
Noticed by: A power failure at my lab
Pointy hat: me
MFC After: 3 days
has only been partly initialized via newfs(8) so that it applies to both
UFS1 and UFS2.
Submitted by: "Xin LI" delphij at frontfree dot net
MFC: maybe?