In ufs_rename case, tdvp is locked from the place where ufs_direnter()
is done till VOP_VPUT_PAIR(), which means that we no longer need to specially
handle rename in ufs_direnter(). Truncation, if possible, is done in the
same way in ffs_vput_pair() both for rename and other VOPs calling
ufs_direnter(). Remove isrename argument and set IN_ENDOFF if
ufs_direnter() succeeded and directory needs truncation.
In ffs_vput_pair(), stop verifying the condition that directory needs
truncation when IN_ENDOFF is set, instead assert that the condition is
true.
Suggested by: mckusick
Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
VOP_VPUT_PAIR() provides the hook to do the truncation right before
unlock, which is required since truncation might need to fsync(), which
itself might unlock the directory vnode.
Set new flag IN_ENDOFF which indicates that i_endoff is valid and should
be checked against inode size. Excessive size is chomped, but this
operation is advisory and failure to truncate should not result in the
failure of the main VOP.
Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
In particular, if unlock_vp is false, save vp's inode number and
generation. If ffs_inotovp() can re-create the vnode with the same
number and generation after we finished with handling dvp, then we most
likely raced with unmount, and were able to restore atomicity of open.
We use FFSV_REPLACE_DOOMED there, to drop the old vnode.
This additional recovery is not strictly required, but it improves the
quality of the implementation.
Suggested by: mckusick
Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
It cleans IN_NEEDSYNC flag on dvp before returning, by applying
ffs_syncvnode() until success or an error different from ERELOOKUP.
IN_NEEDSYNC cleanup is required to avoid creating holes in the directories
when extended into indirect block.
Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
If the snapshot embrio was reclaimed under us, return error outright.
Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
for all kinds of async/SU mount variants.
Submitted by: mckusick
Reviewed by: chs
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
If it is cleaned before the sync, other threads might see the inode without
the flag set, because syncing could unlock it.
Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
The function alone was not used for anything but ffs_fstovp() for long time.
Suggested by: mckusick
Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
It generalizes the VFS_FHTOVP() interface, making it possible to fetch
the inode without faking filehandle. Also it adds the ffs flags argument
which allows to control ffs_vgetf() call.
Requested by: mckusick
Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
It specifies that caller requests a fresh non-doomed vnode. If doomed
vnode is found in the hash, it should behave similarly to FFSV_REPLACE.
Or, to put it differently, the flag is same as FFSV_REPLACE, but only
when the found hashed vnode is doomed.
Reviewed by: chs, mkcusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Later processing of ffs_truncate() might temporary unlock the directory
vnode, causing unsychronized dirhash and inode sizes if update is
postponed to UFS_TRUNCATE() callers.
Reviewed by: chs, mkcusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
and only call buf_complete() if previously started. Some error paths,
like CoW failire, might skip buf_start() and do bufdone(), which itself
call buf_complete().
Various SU handle_written_XXX() functions check that io was started
and incomplete parts of the buffer data reverted before restoring them.
This is a useful invariant that B_IO_STARTED on buffer layer allows to
keep instead of changing check and panic into check and return.
Reported by: pho
Reviewed by: chs, mckusick
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundations
as it is done in other places. Header files might need options defined
for correct operation.
Reviewed by: chs, mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
After discussion with Chuck Silvers (chs@) we have decided that
there is a better way to resolve this lock order reversal which
will be committed separately.
Sponsored by: Netflix
disk failure.
Each vnode has an embedded lock that controls access to its contents.
However vnodes describing a UFS snapshot all share a single snapshot
lock to coordinate their access and update. As part of mounting a
UFS filesystem with snapshots, each of the vnodes describing a
snapshot has its individual lock replaced with the snapshot lock.
When the filesystem is unmounted the vnode's original lock is
returned replacing the snapshot lock.
When a disk fails while the UFS filesystem it contains is still
mounted (for example when a thumb drive is removed) UFS forcibly
unmounts the filesystem. The loss of the drive causes the GEOM
subsystem to orphan the provider, but the consumer remains until
the filesystem has finished with the unmount. Information describing
the snapshot locks was being prematurely cleared during the orphaning
causing the return of the snapshot vnode's original locks to fail.
The fix is to not clear the needed information prematurely.
Sponsored by: Netflix
with snapshots.
Each vnode has an embedded lock that controls access to its contents.
However vnodes describing a UFS snapshot all share a single snapshot
lock to coordinate their access and update. As part of mounting a
UFS filesystem with snapshots, each of the vnodes describing a
snapshot has its individual lock replaced with the snapshot lock.
When the filesystem is unmounted the vnode's original lock is
returned replacing the snapshot lock.
The lock order reversal happens because vnode locks must be acquired
before snapshot locks. When unmounting we must lock both the snapshot
lock and the vnode lock before swapping them so that the vnode will
be continuously locked during the swap. For each vnode representing
a snapshot, we must first acquire the snapshot lock to ensure
exclusive access to it and its original lock. We then face a lock
order reversal when we try to acquire the original vnode lock. The
problem is eliminated by doing a non-blocking exclusive lock on the
original lock which will always succeed since there are no users
of that lock.
Sponsored by: Netflix
UFS uses a new "mntfs" pseudo file system which provides private
device vnodes for a file system to safely access its disk device.
The original device vnode is saved in um_odevvp to hold the exclusive
lock on the device so that any attempts to open it for writing will
fail. But it is otherwise unused and has its BO_NOBUFS flag set to
enforce that file systems using mntfs vnodes do not accidentally
use the original devfs vnode. When the file system is unmounted,
um_odevvp is no longer needed and is released.
The lock order reversal happens because device vnodes must be locked
before UFS vnodes. During unmount, the root directory vnode lock
is held. When when calling vrele() on um_odevvp, vrele() attempts to
exclusive lock um_odevvp causing the lock order reversal. The problem
is eliminated by doing a non-blocking exclusive lock on um_odevvp
which will always succeed since there are no users of um_odevvp.
With um_odevvp locked, it can be released using vput which does not
attempt to do a blocking exclusive lock request and thus avoids the
lock order reversal.
Sponsored by: Netflix
Respect the new IO_DATASYNC flag when performing synchronous writes.
Compared to O_SYNC, O_DSYNC lets us skip updating the inode in some
cases, matching the behaviour of fdatasync(2).
Reviewed by: kib
Differential Review: https://reviews.freebsd.org/D25160
We use a bitmap to track which cylinder groups have changed between
snapshot creation and filesystem suspension. The "legs" of the bitmap
are four bytes wide (see ACTIVESET()) so we must round up the allocation
size to a multiple of four bytes.
I believe this bug is harmless since UMA/kmem_* will both pad the
allocation and zero the full allocation. Note that malloc() does inline
zeroing when the allocation size is known at compile-time.
Reported by: pho (using KASAN)
Reviewed by: kib, mckusick
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D27731
BA_CLRBUF specifies that existing context of the block will be
completely overwritten by caller, so there is no reason to spend io
fetching existing data. We do the same for indirect blocks.
Reported by: tmunro
Reviewed by: mckusick, tmunro
Tested by: pho, tmunro
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D27353
Replace MAXPHYS by runtime variable maxphys. It is initialized from
MAXPHYS by default, but can be also adjusted with the tunable kern.maxphys.
Make b_pages[] array in struct buf flexible. Size b_pages[] for buffer
cache buffers exactly to atop(maxbcachebuf) (currently it is sized to
atop(MAXPHYS)), and b_pages[] for pbufs is sized to atop(maxphys) + 1.
The +1 for pbufs allow several pbuf consumers, among them vmapbuf(),
to use unaligned buffers still sized to maxphys, esp. when such
buffers come from userspace (*). Overall, we save significant amount
of otherwise wasted memory in b_pages[] for buffer cache buffers,
while bumping MAXPHYS to desired high value.
Eliminate all direct uses of the MAXPHYS constant in kernel and driver
sources, except a place which initialize maxphys. Some random (and
arguably weird) uses of MAXPHYS, e.g. in linuxolator, are converted
straight. Some drivers, which use MAXPHYS to size embeded structures,
get private MAXPHYS-like constant; their convertion is out of scope
for this work.
Changes to cam/, dev/ahci, dev/ata, dev/mpr, dev/mpt, dev/mvs,
dev/siis, where either submitted by, or based on changes by mav.
Suggested by: mav (*)
Reviewed by: imp, mav, imp, mckusick, scottl (intermediate versions)
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D27225
When operating in SU or SU+J mode, ffs_syncvnode() might need to
instantiate other vnode by inode number while owning syncing vnode
lock. Typically this other vnode is the parent of our vnode, but due
to renames occuring right before fsync (or during fsync when we drop
the syncing vnode lock, see below) it might be no longer parent.
More, the called function flush_pagedep_deps() needs to lock other
vnode while owning the lock for vnode which owns the buffer, for which
the dependencies are flushed. This creates another instance of the
same LoR as was fixed in softdep_sync().
Put the generic code for safe relocking into new SU helper
get_parent_vp() and use it in flush_pagedep_deps(). The case for safe
relocking of two vnodes with undefined lock order was extracted into
vn helper vn_lock_pair().
Due to call sequence
ffs_syncvnode()->softdep_sync_buf()->flush_pagedep_deps(),
ffs_syncvnode() indicates with ERELOOKUP that passed vnode was
unlocked in process, and can return ENOENT if the passed vnode
reclaimed. All callers of the function were inspected.
Because UFS namei lookups store auxiliary information about directory
entry in in-memory directory inode, and this information is then used
by UFS code that creates/removed directory entry in the actual
mutating VOPs, it is critical that directory vnode lock is not dropped
between lookup and VOP. For softdep_prelink(), which ensures that
later link/unlink operation can proceed without overflowing the
journal, calls were moved to the place where it is safe to drop
processing VOP because mutations are not yet applied. Then, ERELOOKUP
causes restart of the whole VFS operation (typically VFS syscall) at
top level, including the re-lookup of the involved pathes. [Note that
we already do the same restart for failing calls to vn_start_write(),
so formally this patch does not introduce new behavior.]
Similarly, unsafe calls to fsync in snapshot creation code were
plugged. A possible view on these failures is that it does not make
sense to continue creating snapshot if the snapshot vnode was
reclaimed due to forced unmount.
It is possible that relock/ERELOOKUP situation occurs in
ffs_truncate() called from ufs_inactive(). In this case, dropping the
vnode lock is not safe. Detect the situation with VI_DOINGINACT and
reschedule inactivation by setting VI_OWEINACT. ufs_inactive()
rechecks VI_OWEINACT and avoids reclaiming vnode is truncation failed
this way.
In ffs_truncate(), allocation of the EOF block for partial truncation
is re-done after vnode is synced, since we cannot leave the buffer
locked through ffs_syncvnode().
In collaboration with: pho
Reviewed by: mckusick (previous version), markj
Tested by: markj (syzkaller), pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26136
This count is memoized together with the lookup metadata in directory
inode, and we assert that accesses to lookup metadata are done under
the same lock generation as they were stored. Enabled under DIAGNOSTICS.
UFS saves additional data for parent dirent when doing lookup
(i_offset, i_count, i_endoff), and this data is used later by VOPs
operating on dirents. If parent vnode exclusive lock is dropped and
re-acquired between lookup and the VOP call, we corrupt directories.
Framework asserts that corruption cannot occur that way, by tracking
vnode lock generation counter. Updates to inode dirent members also
save the counter, while users compare current and saved counters
values.
Also, fix a case in ufs_lookup_ino() where i_offset and i_count could
be updated under shared lock. It is not a bug on its own since dvp
i_offset results from such lookup cannot be used, but it causes false
positive in the checker.
In collaboration with: pho
Reviewed by: mckusick (previous version), markj
Tested by: markj (syzkaller), pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26136
This count is memoized together with the lookup metadata in directory
inode, and we assert that accesses to lookup metadata are done under
the same lock generation as they were stored. Enabled under DIAGNOSTICS.
UFS saves additional data for parent dirent when doing lookup
(i_offset, i_count, i_endoff), and this data is used later by VOPs
operating on dirents. If parent vnode exclusive lock is dropped and
re-acquired between lookup and the VOP call, we corrupt directories.
Framework asserts that corruption cannot occur that way, by tracking
vnode lock generation counter. Updates to inode dirent members also
save the counter, while users compare current and saved counters
values.
Also, fix a case in ufs_lookup_ino() where i_offset and i_count could
be updated under shared lock. It is not a bug on its own since dvp
i_offset results from such lookup cannot be used, but it causes false
positive in the checker.
In collaboration with: pho
Reviewed by: mckusick (previous version), markj
Tested by: markj (syzkaller), pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26136
On 32-bit platforms, the computed size of the BIO_SPEEDUP requested by
softdep_request_cleanup() may be negative when assigned to bp->b_bcount,
which has type "long".
Clamp the size to LONG_MAX. Also convert the unused g_io_speedup() to
use an off_t for the magnitude of the shortage for consistency with
softdep_send_speedup().
Reviewed by: chs, kib
Reported by: pho
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D27081
Prior versions of FreeBSD (11.x) may have produced a corrupt extattr file.
(Specifically, r312416 accidentally fixed this defect by removing a strcpy.)
CURRENT FreeBSD supports disk images from those prior versions of FreeBSD.
Validate the internal structure as soon as we read it in from disk, to
prevent these extattr files from causing invariants violations and DoS.
Attempting to access the extattr portion of these files results in
EINTEGRITY. At this time, the only way to repair files damaged in this way
is to copy the contents to another file and move it over the original.
PR: 244089
Reported by: Andrea Venturoli <ml AT netfence.it>
Reviewed by: kib
Discussed with: mckusick (earlier draft)
Security: no
Differential Revision: https://reviews.freebsd.org/D27010
Foundation copyrights, approved by emaste@. It does not include
files which carry other people's copyrights; if you're one
of those people, feel free to make similar change.
Reviewed by: emaste, imp, gbe (manpages)
Differential Revision: https://reviews.freebsd.org/D26980
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
Instead, add arguments to vmapbuf. Since this argument is
always a pointer use a type of void * and cast to vm_offset_t in
vmapbuf. (In CheriBSD we've altered vm_fault_quick_hold_pages to
take a pointer and check its bounds.)
In no other situtation does b_data contain a user pointer and vmapbuf
replaces b_data with the actual mapping.
Suggested by: jhb
Reviewed by: imp, jhb
Obtained from: CheriBSD
MFC after: 1 week
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D26784
Normally when a buffer with B_BARRIER is written, the flag is cleared
by g_vfs_strategy() when creating bio. But in some cases FFS buffer
might not reach g_vfs_strategy(), for instance when copy-on-write
reports an error like ENOSPC. In this case buffer is returned to
dirty queue and might be written later by other means. Among then
bdwrite() reasonably asserts that B_BARRIER is not set.
In fact, the only current use of B_BARRIER is for lazy inode block
initialization, where write of the new inode block is fenced against
cylinder group write to mark inode as used. The situation could be
seen that we break dependency by updating cg without written out
inode. Practically since CoW was not able to find space for a copy of
inode block, for the same reason cg group block write should fail.
Reported by: pho
Discussed with: chs, imp, mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D26511
switch ufs_stat() to use the same value for st_dev as was used by
the previous ufs_getattr() stat path.
Submitted by: gallatin
Reviewed by: mjg, imp, kib, mckusick
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D26596
There are several negative side-effects of not calling into VOP layer
at all for page cache reads. The biggest is the missed activation of
EVFILT_READ knotes.
Also, it allows filesystem to make more fine grained decision to
refuse read from page cache.
Keep VIRF_PGREAD flag around, it is still useful for nullfs, and for
asserts.
Reviewed by: markj
Tested by: pho
Discussed with: mjg
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26346
The pointer to vnode is already stored into f_vnode, so f_data can be
reused. Fix all found users of f_data for DTYPE_VNODE.
Provide finit_vnode() helper to initialize file of DTYPE_VNODE type.
Reviewed by: markj (previous version)
Discussed with: freqlabs (openzfs chunk)
Tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26346
Move v_object creation earlier, so that VIRF_PGREAD is never set if
v_object is NULL. There is no much harm from instantiating v_object
when later check for append-only flags disallows open.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D25968
ACLs are not supported, meaning their presence will force the use of the old lookup.
Reviewed by: kib
Tested by: pho (in a patchset)
Differential Revision: https://reviews.freebsd.org/D25579
It is very conservative. Only spinning when LK_ADAPTIVE is passed, only on
exclusive lock and never when any waiters are present. buffer cache is remains
not spinning.
This reduces total sleep times during buildworld etc., but it does not shorten
total real time (culprits are contention in the vm subsystem along with slock +
upgrade which is not covered).
For microbenchmarks: open3_processes -t 52 (open/close of the same file for
writing) ops/s:
before: 258845
after: 801638
Reviewed by: kib
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D25753
out verbatim to the disk: see ffs_sbput() in sys/ufs/ffs/ffs_subr.c.
It contains a pointer to the fs_summary_info structure. This pointer
value inadvertently causes garbage to be stored. It is garbage because
the pointer to the fs_summary_info structure is the address the then
current stack or heap. Although a mere pointer does not reveal anything
useful (like a part of a private key) to an attacker, garbage output
deteriorates reproducibility.
This commit zeros out the pointer to the fs_summary_info structure
before writing the out the superblock.
Reviewed by: kib
Tested by: Peter Holm
PR: 246983
Sponsored by: Netflix
fs_summary_info structure. This change was originally done
by the CheriBSD project as they need larger pointers that
do not fit in the existing superblock.
This cleanup of the superblock eases the task of the commit
that immediately follows this one.
Suggested by: brooks
Reviewed by: kib
PR: 246983
Sponsored by: Netflix
module from that file into ffs_vfsops.c. This fixes the build for kernel
configs that don't include FFS.
PR: 247256
Submitted by: glebius
Reviewed by: mckusick (earlier version)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D25285
Since mnt_flags was upgraded to 64bits there has been a quirk in
"struct export_args", since it hold a copy of mnt_flags
in ex_flags, which is an "int" (32bits).
This happens to currently work, since all the flag bits used in ex_flags are
defined in the low order 32bits. However, new export flags cannot be defined.
Also, ex_anon is a "struct xucred", which limits it to 16 additional groups.
This patch revises "struct export_args" to make ex_flags 64bits and replaces
ex_anon with ex_uid, ex_ngroups and ex_groups (which points to a
groups list, so it can be malloc'd up to NGROUPS in size.
This requires that the VFS_CHECKEXP() arguments change, so I also modified the
last "secflavors" argument to be an array pointer, so that the
secflavors could be copied in VFS_CHECKEXP() while the export entry is locked.
(Without this patch VFS_CHECKEXP() returns a pointer to the secflavors
array and then it is used after being unlocked, which is potentially
a problem if the exports entry is changed.
In practice this does not occur when mountd is run with "-S",
but I think it is worth fixing.)
This patch also deleted the vfs_oexport_conv() function, since
do_mount_update() does the conversion, as required by the old vfs_cmount()
calls.
Reviewed by: kib, freqlabs
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D25088
synchronous inode update.
The IN_SIZEMOD and IN_IBLKDATA flags indicate changes to the
file size and block pointer fields in the inode. When these
fields have been changed, the fsync() and fsyncdata() system
calls must write the inode to ensure their semantics that the
file is on stable store.
The IN_SIZEMOD and IN_IBLKDATA flags cannot be cleared until
a synchronous write of the inode is done. If they are cleared
on an asynchronous write, then the inode may not yet have been
written to the disk when an fsync() or fsyncdata() call is done.
Absent these flags, these calls would not know that they needed
to write the inode. Thus, these flags only can be cleared on
synchronous writes of the inode. Since the inode will be locked
for the duration of the I/O that writes it to disk, no fsync()
or fsyncdata() will be able to run before the on-disk inode
is complete.
Reviewed by: kib
MFC with: -r361785
Differential revision: https://reviews.freebsd.org/D25072
requires that new data on growing files be accessible. Thus, the
the fsyncdata() system call must update the on-disk inode when the
size of the file has changed.
This commit adds another inode update flag, IN_SIZEMOD, that gets
set any time that the file size changes. If either the IN_IBLKDATA
or the IN_SIZEMOD flag is set when fdatasync() is called, the
associated inode is synchronously written to disk. We could have
overloaded the IN_IBLKDATA flag to also track size changes since
the only (current) use case for these flags are for fsyncdata(),
but it does seem useful for possible future uses to separately
track the file size changes and the inode block pointer changes.
Reviewed by: kib
MFC with: -r361785
Differential revision: https://reviews.freebsd.org/D25072
The fdatasync() description in POSIX specifies that
all I/O operations shall be completed as defined for synchronized I/O
data integrity completion.
and then the explanation of Synchronized I/O Data Integrity Completion says
The write is complete only when the data specified in the write
request is successfully transferred and all file system
information required to retrieve the data is successfully
transferred.
For UFS this means that all pointers must be on disk. Indirect
pointers already contribute to the list of dirty data blocks, so only
direct blocks and root pointers to indirect blocks, both of which
reside in the inode block, should be taken care of. In ffs_balloc(),
mark the inode with the new flag IN_IBLKDATA that specifies that
ffs_syncvnode(DATA_ONLY) needs a call to ffs_update() to flush the
inode block.
Reviewed by: mckusick
Discussed with: tmunro
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D25072
the underlying media fails or becomes inaccessible. For example
when a USB flash memory card hosting a UFS filesystem is unplugged.
The strategy for handling disk I/O errors when soft updates are
enabled is to stop writing to the disk of the affected file system
but continue to accept I/O requests and report that all future
writes by the file system to that disk actually succeed. Then
initiate an asynchronous forced unmount of the affected file system.
There are two cases for disk I/O errors:
- ENXIO, which means that this disk is gone and the lower layers
of the storage stack already guarantee that no future I/O to
this disk will succeed.
- EIO (or most other errors), which means that this particular
I/O request has failed but subsequent I/O requests to this
disk might still succeed.
For ENXIO, we can just clear the error and continue, because we
know that the file system cannot affect the on-disk state after we
see this error. For EIO or other errors, we arrange for the geom_vfs
layer to reject all future I/O requests with ENXIO just like is
done when the geom_vfs is orphaned. In both cases, the file system
code can just clear the error and proceed with the forcible unmount.
This new treatment of I/O errors is needed for writes of any buffer
that is involved in a dependency. Most dependencies are described
by a structure attached to the buffer's b_dep field. But some are
created and processed as a result of the completion of the dependencies
attached to the buffer.
Clearing of some dependencies require a read. For example if there
is a dependency that requires an inode to be written, the disk block
containing that inode must be read, the updated inode copied into
place in that buffer, and the buffer then written back to disk.
Often the needed buffer is already in memory and can be used. But
if it needs to be read from the disk, the read will fail, so we
fabricate a buffer full of zeroes and pretend that the read succeeded.
This zero'ed buffer can be updated and written back to disk.
The only case where a buffer full of zeros causes the code to do
the wrong thing is when reading an inode buffer containing an inode
that still has an inode dependency in memory that will reinitialize
the effective link count (i_effnlink) based on the actual link count
(i_nlink) that we read. To handle this case we now store the i_nlink
value that we wrote in the inode dependency so that it can be
restored into the zero'ed buffer thus keeping the tracking of the
inode link count consistent.
Because applications depend on knowing when an attempt to write
their data to stable storage has failed, the fsync(2) and msync(2)
system calls need to return errors if data fails to be written to
stable storage. So these operations return ENXIO for every call
made on files in a file system where we have otherwise been ignoring
I/O errors.
Coauthered by: mckusick
Reviewed by: kib
Tested by: Peter Holm
Approved by: mckusick (mentor)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D24088
These two sysctls were added to support UFS softupdates journalling
with snapshots. However, the changes to fsck to use them were never
committed and there have never been any in-tree uses of these sysctls.
More details from Kirk:
When journalling got added to soft updates, its journal rollback freed
blocks that it thought were no longer in use. But it does not take
snapshots into account (i.e., if a snapshot is still using it, then it
cannot be freed). So I added the needed logic to fsck by having the
free go through the kernel's blkfree code so it could grab blocks that
were still needed by snapshots. That is done using the setbufoutput
hack. I never got that code working reliably, so it is still sitting
in my work directory. Which also explains why you still cannot take
snapshots on filesystems running with journalling...
In looking over my use of this feature, and in particular the troubles
I was having with it, I conclude that it may be better to extract the
code from the kernel that handles freeing blocks claimed by snapshots
and putting it into fsck directly. My original intent was that it is
complex and at the time changing, so only having to maintain it in one
place was appealing. But at this point it has not changed in years and
the hacks like setinode and setbufoutput to be able to use the kernel
code is sufficiently ugly, that I am leaning towards just extracting
it.
Reviewed by: mckusick
MFC after: 1 week
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D24484
Forced rw unmounts and remounts from rw to ro already suspend
filesystem, which closes races with writers instantiating new vnodes
while unmount flushes the queue. Original intent of not including
non-forced unmounts into this regime was to allow such unmounts to
fail if writer was active, but this did not worked well.
Similar change, but causing all unmount, even involving only ro
filesystem, were proposed in D24088, but I believe that suspending ro
is undesirable, and definitely spends CPU time.
Reported by: markj
Discussed with: chs, mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
hidden bug in the file truncation code. Until that bug is tracked
down and fixed, revert to the old behavior.
Reported by: Peter Holm
Reviewed by: kib, Chuck Silvers
sync it to disk before shrinking it. Complete the sync before getting
the buffer for the block to be updated to do the shrink to avoid
panicing with a recursive lock on one of the directory's buffers.
Reviewed by: Chuck Silvers (chs)
MFC after: 3 days
Sponsored by: Netflix
boolean expressions so that their values are not lost when assigned to
`bool' or `int' variables.
Reviewed by: Chuck Silvers (chs)
MFC after: 3 days
Sponsored by: Netflix
when a superblock check-hash error is detected. This change clarifies
a mount that failed due to media hardware failures (EIO) from a mount
that failed due to media errors (EINTEGRITY) that can be corrected by
running fsck(8).
Sponsored by: Netflix
This has a side effect of eliminating filedesc slock/sunlock during path
lookup, which in turn removes contention vs concurrent modifications to the fd
table.
Reviewed by: markj, kib
Differential Revision: https://reviews.freebsd.org/D23889
file systems to safely access their disk devices, and adapt FFS to use it.
Also add a new BO_NOBUFS flag to allow enforcing that file systems using
mntfs vnodes do not accidentally use the original devfs vnode to create buffers.
Reviewed by: kib, mckusick
Approved by: imp (mentor)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D23787
The new structure is copy-on-write. With the assumption that path lookups are
significantly more frequent than chdirs and chrooting this is a win.
This provides stable root and jail root vnodes without the need to reference
them on lookup, which in turn means less work on globally shared structures.
Note this also happens to fix a bug where jail vnode was never referenced,
meaning subsequent access on lookup could run into use-after-free.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D23884
r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.
This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.
Mark all obvious cases as MPSAFE. All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT
Approved by: kib (mentor, blanket)
Commented by: kib, gallatin, melifaro
Differential Revision: https://reviews.freebsd.org/D23718
The routine is only called on mmap and exec, both of which are invalid for
this type.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D23421
This mostly eliminates the requirement that vput never unlocks the vnode
before calling VOP_INACTIVE. Note it may still be present for other
filesystems.
See r356126 for an example bug.
Note vput stopped doing early unlock in r357070 thus this change does
not affect correctness as it is.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D23215
vget is almost always called with LK_SHARED, meaning the flag (if present) is
almost guaranteed to get cleared. Stop handling it in the first place and
instead let the thread which wanted to do inactive handle the bumepd usecount.
Reviewed by: jeff
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D23184
Only send a speedup when there's a shortage. While this is a little racy, lost
races aren't a big deal for this function. If there's a shorage just popping up
after we check these values, then we'll catch it next time. If there's a
shortage that's just clearing up, we may do some work at the lower layers a
little sooner than we otherwise would have. Sicne shortages are relatively rare
events, both races are acceptable.
Reviewed by: chs
Differential Revision: https://reviews.freebsd.org/D23182
It turns out there's a problem with using g_io to send the speedup. It leads to
a race when there's a resource shortage when a disk fails.
Instead, send BIO_SPEEDUP via struct buf. This is pretty straight forward,
except we need to transfer the bio_flags from b_ioflags for BIO_SPEEDUP commands
in g_vfs_strategy.
Reviewed by: kirk, chs
Differential Revision: https://reviews.freebsd.org/D23117
twice. Once to update the changed inodes, and a second time to update
changed quota information. This change merges these two scans into a
single scan which does both inode and quota updates.
MFC after: 7 days
needs to handle file removal, directory removal, file move, directory move,
etc. The code in handle_workitem_remove() needs to propagate any completed
journal entries to the write that will render the change stable. In the
case of a moved directory this means the new parent. However, for an
overwrite that frees a directory (DIRCHG) we must move the jsegdep to the
removed inode to be released when it is stable in the cg bitmap or the
unlinked inode list. This case was previously unhandled and caused a
panic.
Reported by: mckusick, pho
Reviewed by: mckusick
Tested by: pho
Part of i_flag can persist across a drop to hold count of 0, at which
point the vnode is taken off the lazy list. Then whoever locks and unlocks
the vnode can trip on the assert.
This trips over kyua running a test untarring character devices to ufs.
Reported by: lwhsu
The current notion of an active vnode is eliminated.
Vnodes transition between 0<->1 hold counts all the time and the
associated traversal between different lists induces significant
scalability problems in certain workloads.
Introduce a global list containing all allocated vnodes. They get
unlinked only when UMA reclaims memory and are only requeued when
hold count reaches 0.
Sample result from an incremental make -s -j 104 bzImage on tmpfs:
stock: 118.55s user 3649.73s system 7479% cpu 50.382 total
patched: 122.38s user 1780.45s system 6242% cpu 30.480 total
Reviewed by: jeff
Tested by: pho (in a larger patch, previous version)
Differential Revision: https://reviews.freebsd.org/D22997
Quota code is temporarily regressed to do a full vnode scan.
Reviewed by: jeff
Tested by: pho (in a larger patch, previous version)
Differential Revision: https://reviews.freebsd.org/D22996
This will be used later to add vnodes to the lazy list.
Reviewed by: kib (previous version), jeff
Tested by: pho (in a larger patch)
Differential Revision: https://reviews.freebsd.org/D22994
or rename an entry in it, properly reset the link count of the inode
associated with the entry that was to have been changed.
Tested by: Peter Holm
MFC after: 7 days
Filesystems which want to use it in limited capacity can employ the
VOP_UNLOCK_FLAGS macro.
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D21427
After a recent change, vput() relocks even the exclusively locked
vnode before inactivating it. Before that, UFS could safely
instantiate a vnode for cleared inode, then the last vput() after
ffs_vgetf() noted that ip->i_mode == 0 and recycled. Now, it is
possible for other threads to note the half-constructed vnode, e.g. to
insert it into hash, which makes other threads to use it despite mode
is zero, before inactivation and reclaim.
Handle the found cases in SU code, by explicitly doing reclaim.
Assert that other places get fully constructed inode from ffs_vgetf(),
which cannot be cleared before dependencies are resolved.
Reported and tested by: pho
Reviewed by: mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
g_io_speedup waits for the completion of the speedup request before proceeding
using biowait(), but check_clear_deps is called with the softdeps lock held
(which is non-sleepable). It's safe to drop this lock around the call to
speedup, so do that.
Submitted by: Peter Holm
Reviewed by: kib@
When we have a resource shortage in UFS, send down a BIO_SPEEDUP to
give the CAM I/O scheduler a heads up that we have a resource shortage
and that it should bias its decisions knowing that.
Reviewed by: kirk, kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D18351
The checks literally repeat conditions that make ufs_inactive() to
take some actions.
Reviewed by: jeff
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D22616
The current vnode layout is not smp-friendly by having frequently read data
avoidably sharing cachelines with very frequently modified fields. In
particular v_iflag inspected for VI_DOOMED can be found in the same line with
v_usecount. Instead make it available in the same cacheline as the v_op, v_data
and v_type which all get read all the time.
v_type is avoidably 4 bytes while the necessary data will easily fit in 1.
Shrinking it frees up 3 bytes, 2 of which get used here to introduce a new
flag field with a new value: VIRF_DOOMED.
Reviewed by: kib, jeff
Differential Revision: https://reviews.freebsd.org/D22715
the vnode, logical block number, and size of data block that is
being requested. They then use the VOP_BMAP function to calculate
the mapping from logical block number to physical block number from
which to access the data. This change expands the interface to also
pass the physical block number in cases where the VOP_MAP function
may no longer work, for example when a file is being truncated.
No functional change.
Reviewed by: kib
Tested by: Peter Holm
Sponsored by: Netflix
because nothing ever changes this field for read-only mounts and we want
to verify that it is still 0 when we unmount.
Reviewed by: mckusick
Approved by: mckusick (mentor)
Sponsored by: Netflix
the cg rather than reusuing "ino" for this purpose. This reduces the diff
for an upcoming change that improves handling of I/O errors.
No functional change.
Reviewed by: mckusick
Approved by: mckusick (mentor)
Sponsored by: Netflix
flag and use the same system.
This enables further fault locking improvements by allowing more faults to
proceed with a shared lock.
Reviewed by: kib
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D22116
stat() of one of the remaining names of the file does not show an
updated ctime (inode modification time) until several seconds after
the unlink() completes. The problem only occurs when the filesystem
is running with soft updates enabled. When running with soft updates,
the ctime is not updated until the soft updates background process
has settled all the needed I/O operations.
This commit causes the ctime to be updated immediately during the
unlink(). A side effect of this change is that the ctime is updated
again when soft updates has finished its processing because that
is the time that is correct from the perspective of programs that
look at the disk (like dump). This change does not cause any extra
I/O to be done, it just ensures that stat() updates the ctime before
handing it back.
PR: 241373
Reported by: Alan Somers
Tested by: Alan Somers
MFC after: 3 days
Sponsored by: Netflix
have been unlinked, but are still referenced by open file descriptors.
These inodes cannot be freed until the final file descriptor reference
has been closed. If the system crashes while they are still being
referenced, these inodes and their referenced blocks need to be
freed by fsck. By having them on a linked list with the head pointer
in the superblock, fsck can quickly find and process them rather
than having to check every inode in the filesystem to see if it is
unreferenced.
When updating the head pointer of this list of unlinked inodes in
the superblock, the superblock check-hash was not getting updated.
If the system crashed with the incorrect superblock check-hash, the
superblock would appear to be corrupted. This patch ensures that
the superblock check-hash is updated when updating the head pointer
of the unlinked inodes list.
There is no need to MFC as superblock check hashes first appeared in
13.0.
Tested by: Peter Holm
Sponsored by: Netflix
The softdep lock names were unusually long and tended to stick out in
lock profiling reports. Abbreviate them and make them consistent with
our conventional style for lock names.
Reviewed by: mckusick
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D22042
There are 3 counters modified all the time in this structure - one for
keeping the structure alive, one for preventing unmount and one for
tracking active writers. Exact values of these counters are very rarely
needed, which makes them a prime candidate for conversion to a per-cpu
scheme, resulting in much better performance.
Sample benchmark performing fstatfs (modifying 2 out of 3 counters) on
a 104-way 2 socket Skylake system:
before: 852393 ops/s
after: 76682077 ops/s
Reviewed by: kib, jeff
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21637
When softdep_fsync() is running, a caller must already started write
for the mount point. Since unmount or remount to ro suspends mount
point, it cannot run in parallel with softdep_fsync(), which makes
vfs_busy() call there not needed.
Doing blocking vfs_busy() there effectively causes lock order reversal
between vn_start_write() and setting MNTK_UNMOUNT, because
vfs_busy(mp, 0) sleeps waiting for MNTK_UNMOUNT becoming clear, while
unmount sets the flag and starts the suspension.
Note that all other uses of vfs_busy() in SU code are non-blocking.
Reported by: chs by mckusick
Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Current implementation of vnode_create_vobject() and
vnode_destroy_vobject() is written so that it prepared to handle the
vm object destruction for live vnode. Practically, no filesystems use
this, except for some remnants that were present in UFS till today.
One of the consequences of that model is that each filesystem must
call vnode_destroy_vobject() in VOP_RECLAIM() or earlier, as result
all of them get rid of the v_object in reclaim.
Move the call to vnode_destroy_vobject() to vgonel() before
VOP_RECLAIM(). This makes v_object stable: either the object is NULL,
or it is valid vm object till the vnode reclamation. Remove code from
vnode_create_vobject() to handle races with the parallel destruction.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21412
In ffs_valloc(), force reclaim existing vnode on inode reuse, instead
of trying to re-initialize the same vnode for new purposes. This is
done in preparation of changes to the vp->v_object lifecycle handling.
A new FFSV_REPLACE flag to ffs_vgetf() directs the function to
vgone(9) the vnode if found in vfs hash, instead of returning it.
Reviewed by: markj, mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21412
After all the changes, its dynamic scope is same as for MNTK_UNMOUNT,
but to allow the syncer vnode to be re-installed on unmount failure.
But the case of syncer was already handled by using the VV_FORCEINSMQ
flag for quite some time.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
hash was computed and the time that the superblock was copied to a
buffer to be written to disk. The result was a failed superblock
check hash the next time that the superblock was read.
The fix is to compute the check hash after the superblock has been
copied to a buffer to be written.
PR: 236504
Reported by: Peter Holm
Tested by: Peter Holm
Sponsored by: Netflix
disk blocks, set the FORCE flag in the call to chkiq() or chkdq() since
the user is always allowed to return resources and hence there is no need
to check the user's credential .
Reported by: Christopher Krah, Thomas Barabosch, and Jan-Niclas Hilgert of Fraunhofer FKIE
Reported as: FS-1-UFS-1: Denial Of Service in mount (prison_priv_check)
Discussed with: kib
MFC: 1 week
Sponsored by: Netflix
r346932 replaced a call to vn_bmap_seekhole() with a call to
ufs_bmap_seekdata(). Although vn_bmap_seekhole() locks the vnode,
ufs_bmap_seekdata() assumes it is already locked.
This patch adds locking of the vnode before the ufs_bmap_seekdata() call.
If the vn_lock() call fails, it returns EBADF since that is the normal
error returned when a file system is forced dismounted and is already
listed as an error return in the lseek(2) man page.
Discussed with: markj
Reviewed by: kib
filesystems that have block pointers that are out-of-range for their
filesystem. These out-of-range block pointers are corrected by
fsck(8) so are only encountered when an unchecked filesystem is
mounted.
A new "untrusted" flag has been added to the generic mount interface
that can be set when mounting media of unknown provenance or integrity.
For example, a daemon that automounts a filesystem on a flash drive
when it is plugged into a system.
This commit adds a test to UFS/FFS that validates all block numbers
before using them. Because checking for out-of-range blocks adds
unnecessary overhead to normal operation, the tests are only done
when the filesystem is mounted as an "untrusted" filesystem.
Reported by: Christopher Krah, Thomas Barabosch, and Jan-Niclas Hilgert of Fraunhofer FKIE
Reported as: FS-14-UFS-3: Out of bounds read in write-2 (ffs_alloccg)
Reviewed by: kib
Sponsored by: Netflix
filesystem full message is sent to the offending process or the
kernel log if the offending process cannot be identified.
To prevent an explotion of messages, the kernel ppsratecheck()
function is used to limit the messages to one per second. This
revision changes the variable that tracks the rate of these messages
from a systemwide limit to a per-filesystem limit by moving it from
a global variable to a variable in the ufsmount structure.
Suggested by: kib
Reviewed by: kib
Sponsored by: Netflix
is to notify the kernel that the file system is untrusted and it
should use more extensive checks on the file-system's metadata
before using it. This option is intended to be used when mounting
file systems from untrusted media such as USB memory sticks or other
externally-provided media.
It will initially be used by the UFS/FFS file system, but should
likely be expanded to be used by other file systems that may appear
on external media like msdosfs, exfat, and ext2fs.
Reviewed by: kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20786
Assert that the per-mountpoint softdep mutex is held in modified
functions that do not already have this assertion. No functional
change intended.
Reviewed by: kib, mckusick (previous version)
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20741
This ioctl exposes VOP_BMAP information to userland. It can be used by
programs like fragmentation analyzers and optimized cp implementations. But
I'm using it to test fusefs's VOP_BMAP implementation. The "2" in the name
distinguishes it from the similar but incompatible FIBMAP ioctls in NetBSD
and Linux. FIOBMAP2 differs from FIBMAP in that it uses a 64-bit block
number instead of 32-bit, and it also returns runp and runb.
Reviewed by: mckusick
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20705
rename the source to gsb_crc32.c.
This is a prerequisite of unifying kernel zlib instances.
PR: 229763
Submitted by: Yoshihiro Ota <ota at j.email.ne.jp>
Differential Revision: https://reviews.freebsd.org/D20193
vtruncbuf takes a "struct ucred*" argument. AFAICT, it's been unused ever
since that function was first added in r34611. Remove it. Also, remove some
"struct ucred" arguments from fuse and nfs functions that were only used by
vtruncbuf.
Reviewed by: cem
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20377
Similar to r348026, exhaustive search for uses of CTRn() and cross reference
ktr.h includes. Where it was obvious that an OS compat header of some kind
included ktr.h indirectly, .c files were left alone. Some of these files
clearly got ktr.h via header pollution in some scenarios, or tinderbox would
not be passing prior to this revision, but go ahead and explicitly include it
in files using it anyway.
Like r348026, these CUs did not show up in tinderbox as missing the include.
Reported by: peterj (arm64/mp_machdep.c)
X-MFC-With: r347984
Sponsored by: Dell EMC Isilon
kern_execve() locks text vnode exclusive to be able to set and clear
VV_TEXT flag. VV_TEXT is mutually exclusive with the v_writecount > 0
condition.
The change removes VV_TEXT, replacing it with the condition
v_writecount <= -1, and puts v_writecount under the vnode interlock.
Each text reference decrements v_writecount. To clear the text
reference when the segment is unmapped, it is recorded in the
vm_map_entry backed by the text file as MAP_ENTRY_VN_TEXT flag, and
v_writecount is incremented on the map entry removal
The operations like VOP_ADD_WRITECOUNT() and VOP_SET_TEXT() check that
v_writecount does not contradict the desired change. vn_writecheck()
is now racy and its use was eliminated everywhere except access.
Atomic check for writeability and increment of v_writecount is
performed by the VOP. vn_truncate() now increments v_writecount
around VOP_SETATTR() call, lack of which is arguably a bug on its own.
nullfs bypasses v_writecount to the lower vnode always, so nullfs
vnode has its own v_writecount correct, and lower vnode gets all
references, since object->handle is always lower vnode.
On the text vnode' vm object dealloc, the v_writecount value is reset
to zero, and deadfs vop_unset_text short-circuit the operation.
Reclamation of lowervp always reclaims all nullfs vnodes referencing
lowervp first, so no stray references are left.
Reviewed by: markj, trasz
Tested by: mjg, pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 month
Differential revision: https://reviews.freebsd.org/D19923
directory entries that is caused by uninitialized directory entry
padding written to the disk. It can be viewed by any user with read
access to that directory. Up to 3 bytes of kernel stack are disclosed
per file entry, depending on the the amount of padding the kernel
needs to pad out the entry to a 32 bit boundry. The offset in the
kernel stack that is disclosed is a function of the filename size.
Furthermore, if the user can create files in a directory, this 3
byte window can be expanded 3 bytes at a time to a 254 byte window
with 75% of the data in that window exposed. The additional exposure
is done by removing the entry, creating a new entry with a 4-byte
longer name, extracting 3 more bytes by reading the directory, and
repeating until a 252 byte name is created.
This exploit works in part because the area of the kernel stack
that is being disclosed is in an area that typically doesn't change
that often (perhaps a few times a second on a lightly loaded system),
and these file creates and unlinks themselves don't overwrite the
area of kernel stack being disclosed.
It appears that this bug originated with the creation of the Fast
File System in 4.1b-BSD (Circa 1982, more than 36 years ago!), and
is likely present in every Unix or Unix-like system that uses
UFS/FFS. Amazingly, nobody noticed until now.
This update also adds the -z flag to fsck_ffs to have it scrub
the leaked information in the name padding of existing directories.
It only needs to be run once on each UFS/FFS filesystem after a
patched kernel is installed and running.
Submitted by: David G. Lawrence <dg@dglawrence.com>
Reviewed by: kib
MFC after: 1 week
This version fixes the problems identified in r345244.
Reviewed by: kib
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19598
In particular, ensure that writers are not unleashed before SU
structures are initialized. Also, correctly handle MNT_ASYNC before
this.
Reported and tested by: pho
Reviewed by: mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
the file associated with the given file descriptor.
Reviewed by: kib, asomers
Reviewed by: cem, jilles, brooks (they reviewed previous version)
Discussed with: pjd, and many others
Differential Revision: https://reviews.freebsd.org/D14567
This bug was introduced with the change to use softdep_bp_to_mp()
in January 2018 changes -r327723 and -r327821. The softdep_bp_to_mp()
function failed to include VSOCK as one of the valid cases.
Although local-domain sockets do not allocate blocks in the filesystem,
they will allocate blocks if they use extended attributes (such as
ACLs). Thus, softdep_bp_to_mp() needs to return a non-NULL mount
pointer when presented with a socket vnode so that the soft updates
write complete will properly process the soft updates structures
associated with the extended attribute blocks. It was the failure
to process these soft updates structures, thus leaving them hanging
off the buffer, which lead to the "panic: softdep_deallocate_dependencies:
dangling deps" when trying to clean up the buffer after it was written.
PR: 230962
Reported by: 2t8mr7kx9f@protonmail.com
Reviewed by: kib
Tested by: Peter Holm
MFC after: 1 week
Sponsored by: Netflix
The old implementation, at the VFS layer, would map the entire range of
logical blocks between the starting offset and the first data block
following that offset. With large sparse files this is very
inefficient. The VFS currently doesn't provide an interface to improve
upon the current implementation in a generic way.
Add ufs_bmap_seekdata(), which uses the obvious algorithm of scanning
indirect blocks to look for data blocks. Use it instead of
vn_bmap_seekhole() to implement SEEK_DATA.
Reviewed by: kib, mckusick
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19598
kernel vn_printf() routine when printing out vnodes associated with
a UFS filesystem) to also include the inode's link count, effective
link count, generation number, owner, group, flags, size, and for
UFS2 filesystems, the extent size.
Sponsored by: Netflix
Implement ffs_getpages_async(), which when possible calls the asynchronous
flavor of the generic pager's getpages function. When the underlying
block size is larger than the system page size, however, it will invoke
the (synchronous) buffer cache pager, followed by a call to the client
completion routine. This retains true asynchronous completion in the most
common (block size <= page size) case, which is important for the performance
of the new sendfile(2). The behavior in the larger block size case mirrors
the default implementation of VOP_GETPAGES_ASYNC, which most other
filesystems use anyway as they do not override the getpages_async method.
PR: 235708
Reported by: pho
Reviewed by: kib, glebius
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D19340
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
January 2018 changes -r327723 and -r327821. The softdep_bp_to_mp()
function failed to include VFIFO as one of the valid cases.
Although fifo's do not allocate blocks in the filesystem, they will
allocate blocks if they use extended attributes (such as ACLs). Thus,
softdep_bp_to_mp() needs to return a non-NULL mount pointer when
presented with a fifo vnode so that the soft updates write complete
will properly process the soft updates structures associated with the
extended attribute blocks. It was the failure to process these soft
updates structures, thus leaving them hanging off the buffer, which
lead to the "panic: softdep_deallocate_dependencies: dangling deps"
when trying to clean up the buffer after it was written.
PR: 230962
Reported by: 2t8mr7kx9f@protonmail.com
Reviewed by: kib
Tested by: Peter Holm
MFC after: 1 week
Sponsored by: Netflix
set of known soft dependency data structures now includes: sd_worklist,
sd_inodedep, sd_allocdirect, sd_allocindir, and sd_mkdir. DDB can
also print lists of sd_allinodedeps, sd_mkdir_list, and sd_workhead.
The sd_workhead script is useful for listing all the dependencies
associated with a buffer, e.g. bp->b_dep.
Prefix the soft dependency show names with sd_ so that they sort
together when listed by DDB's "show help" and to distinguish them
from other data structures printable by DDB.
Sponsored by: Netflix
o In vm_pager_bufferinit() create pbuf_zone and start accounting on how many
pbufs are we going to have set.
In various subsystems that are going to utilize pbufs create private zones
via call to pbuf_zsecond_create(). The latter calls uma_zsecond_create(),
and sets a limit on created zone. After startup preallocate pbufs according
to requirements of all pbuf zones.
Subsystems that used to have a private limit with old allocator now have
private pbuf zones: md(4), fusefs, NFS client, smbfs, VFS cluster, FFS,
swap, vnode pager.
The following subsystems use shared pbuf zone: cam(4), nvme(4), physio(9),
aio(4). They should have their private limits, but changing that is out of
scope of this commit.
o Fetch tunable value of kern.nswbuf from init_param2() and while here move
NSWBUF_MIN to opt_param.h and eliminate opt_swap.h, that was holding only
this option.
Default values aren't touched by this commit, but they probably should be
reviewed wrt to modern hardware.
This change removes a tight bottleneck from sendfile(2) operation, that
uses pbufs in vnode pager. Other pagers also would benefit from faster
allocation.
Together with: gallatin
Tested by: pho
vnodeops make FFS1's fifoops1 use ffs_lock. Also delete ffs_reallocblks
from fifoops1 which is needed only for fifoops2 because of its
support for extended attributes that need to allocate blocks.
Suggested by: kib
If invalid, return EINVAL. Note that inode check-hashes greatly
reduce the chance that these errors will go undetected.
Reported by: Christopher Krah <krah@protonmail.com>
Reported as: FS-5-UFS-2: Denial Of Service in nmount-3 (ffs_read)
Reviewed by: kib
MFC after: 1 week
Sponsored by: Netflix
M sys/fs/ext2fs/ext2_vnops.c
M sys/kern/vfs_subr.c
M sys/ufs/ffs/ffs_snapshot.c
M sys/ufs/ufs/ufs_vnops.c
The vnode is not opened, so it ends up with the malloced buffers otherwise.
Reported and tested by: pho
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
the check-hash fails. Prior to the fix in -r342133 the inode with the
zeroed out check-hash was written back to disk causing further confusion.
Reported by: Gary Jennejohn (gj)
Sponsored by: Netflix
before copying in the inode so that the mode and link-count are not set
if the check-hash fails. This change ensures that the vnode will be properly
unwound and recycled rather than being held in the cache.
Initialize the file mode is zero so that if the loading of the inode
fails (for example because of a check-hash failure), the vnode will be
properly unwound and recycled.
Reported by: Gary Jennejohn (gj)
Sponsored by: Netflix
"panic: softdep_update_inodeblock: bad link count" when releasing
a partially initialized vnode after an inode check-hash failure.
Reported by: Gary Jennejohn <gljennjohn@gmail.com>
Reported by: Peter Holm (pho)
Sponsored by: Netflix
check hash to the filesystem inodes. Access attempts to files
associated with an inode with an invalid check hash will fail with
EINVAL (Invalid argument). Access is reestablished after an fsck
is run to find and validate the inodes with invalid check-hashes.
This check avoids a class of filesystem panics related to corrupted
inodes. The hash is done using crc32c.
Note this check-hash is for the inode itself and not any of its
indirect blocks. Check-hash validation may be extended to also
cover indirect block pointers, but that will be a separate (and
more costly) feature.
Check hashes are added only to UFS2 and not to UFS1 as UFS1 is
primarily used in embedded systems with small memories and low-powered
processors which need as light-weight a filesystem as possible.
Reviewed by: kib
Tested by: Peter Holm
Sponsored by: Netflix
deletion is active, specifically after a call to ffs_blkrelease_start()
but before the call to ffs_blkrelease_finish(), ffs_blkrelease_start()
will have handed out SINGLETON_KEY rather than starting a collection
sequence. Thus if we get a SINGLETON_KEY passed to ffs_blkrelease_finish(),
we just return rather than trying to finish the nonexistent sequence.
Reported by: Warner Losh (imp@)
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
predates metadata check hashes so that it is done before deciding
whether to compute a check-hash of the superblock.
Reported by: Rick Macklem <rmacklem@uoguelph.ca>
Sponsored by: Netflix
This corrects a bug that prevented snapshots from being mounted due to a
superblock check-hash failure.
Reported by: Brennan Vincent <brennan@umanwizard.com>
Tested by: Peter Holm (pho@)
Sponsored by: Netflix
Directory entries must be padded to maintain alignment; in many
filesystems the padding was not initialized, resulting in stack
memory being copied out to userspace. With the ino64 work there
are also some explicit pad fields in struct dirent. Add a subroutine
to clear these bytes and use it in the in-tree filesystems. The
NFS client is omitted for now as it was fixed separately in r340787.
Reported by: Thomas Barabosch, Fraunhofer FKIE
Reviewed by: kib
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
The d_off field has been added to the dirent structure recently.
Currently filesystems don't support this feature. Support has been
added and tested for zfs, ufs, ext2fs, fdescfs, msdosfs and unionfs.
A stub implementation is available for cd9660, nandfs, udf and
pseudofs but hasn't been tested.
Motivation for this feature: our usecase is for a userspace nfs server
(nfs-ganesha) with zfs. At the moment we cache direntry offsets by
calling lseek once per entry, with this patch we can get the offset
directly from getdirentries(2) calls which provides a significant
speedup.
Submitted by: Jack Halford <jack@gandi.net>
Reviewed by: mckusick, pfg, rmacklem (previous versions)
Sponsored by: Gandi.net
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D17917
document the libufs interface for fetching and storing inodes.
The undocumented getino / putino interface has been replaced
with a new getinode / putinode interface.
Convert the utilities that had been using the undocumented
interface to use the new documented interface.
No functional change (as for now the libufs library does not
do inode check-hashes).
Reviewed by: kib
Tested by: Peter Holm
Sponsored by: Netflix
This will enable callers to take const paths as part of syscall
decleration improvements.
Where doing so is easy and non-distruptive carry the const through
implementations. In UFS the value is passed to an interface that must
take non-const values. In ZFS, const poisoning would touch code shared
with upstream and it's not worth adding diffs.
Bump __FreeBSD_version for external API consumers.
Reviewed by: kib (prior version)
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D17805
Flags prevent open(2) and *at(2) vfs syscalls name lookup from
escaping the starting directory. Supposedly the interface is similar
to the same proposed Linux flags.
Reviewed by: jilles (code, previous version of manpages), 0mp (manpages)
Discussed with: allanjude, emaste, jonathan
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D17547
check hash to the superblock. If a check hash fails when an attempt
is made to mount a filesystem, the mount fails with EINVAL (Invalid
argument). This avoids a class of filesystem panics related to
corrupted superblocks. The hash is done using crc32c.
Check hases are added only to UFS2 and not to UFS1 as UFS1 is primarily
used in embedded systems with small memories and low-powered processors
which need as light-weight a filesystem as possible.
Reviewed by: kib
Tested by: Peter Holm
Sponsored by: Netflix
UFS quotaoff iterates over all mp vnodes, and derefences and clears
the pointers to corresponding dquots. If SU work items transiently
reference some of dquots,quotaoff() would eventually fail, but all
processed vnodes are already stripped from dquots. The state is
problematic, since quotas are left enabled, but there is no dquots
where blocks and inodes can be accounted. The result is assertion
failures and NULL pointer dereferences.
Fix it by suspending writes around quotaoff() call. Since the
filesystem is synced, no dandling references to dquots from SU
workitems can left behind, which means that quotaoff succeeds.
The complication there is that quotaoff VFS op is performed with the
mount point busied, while to suspend, we need to start write on the
mp. If vn_start_write() is called on busied mp, system might deadlock
against parallel unmount request. Handle this by unbusy-ing mp before
starting write, which in turn requires changing the quotaoff()
interface to return with the mount point not busied, same as was done
for quotaon().
Reviewed by: mckusick
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
Approved by: re (gjb)
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D17208
Doing so can deadlock when the thread already owns another vnode lock,
e.g. during a rename, as was demonstrated by the reporter. In fact,
there seems to be no need to force the call to getinoquota() always,
because vn_open() locks vnode exclusively, and this is the most
important case. To add to the point, directories where the dirent is
added or removed, are locked exclusively as well.
Reported by: bwidawsk
Tested by: bwidawsk, pho (as part of the larger patch)
Sponsored by: The FreeBSD Foundation
Approved by: re (gjb)
MFC after: 1 week
found that performance was no worse and usually better when running
with TRIM consolidation. Performance improvement was most noticable
when multiple large files are released in a short period of time.
Thus, TRIM consolidation is being enabled by default. Should
operational problems be found, it can be disabled using the command
`sysctl vfs.ffs.dotrimcons=0'. This variable can also be set as a
tunable if early disabling is necessary.
Approved by: re (gjb)
Sponsored by: Netflix
given in random(4).
This includes updating of the relevant man pages, and no-longer-used
harvesting parameters.
Ensure that the pseudo-unit-test still does something useful, now also
with the "other" algorithm instead of Yarrow.
PR: 230870
Reviewed by: cem
Approved by: so(delphij,gtetlow)
Approved by: re(marius)
Differential Revision: https://reviews.freebsd.org/D16898
blocks of a file as contiguously as possible. Since the filesystem
does not know how large a file will grow when it is first being
written, it initially places the file in a set of blocks in which
it currently fits. As it grows, it is relocated to areas with
larger contiguous blocks. In this way it saves its large contiguous
sets of blocks for the files that need them and thus avoids
unnecessaily fragmenting its disk space.
We used to skip reallocating the blocks of a file into a contiguous
sequence if the underlying flash device requested BIO_DELETE
notifications, because devices that benefit from BIO_DELETE also
benefit from not moving the data. However, in the algorithm described
above that reallocates the blocks, the destination for the data is
usually moved before the data is written to the initially allocated
location. So we rarely suffer the penalty of extra writes. With
the addition of the consolodation of contiguous blocks into single
BIO_DELETE operations, having fewer but larger contiguous blocks
reduces the number of (slow and expensive) BIO_DELETE operations.
So when doing BIO_DELETE consolodation, we do block reallocation.
Reviewed by: kib
Tested by: Peter Holm
Sponsored by: Netflix
When deleting files on filesystems that are stored on flash-memory
(solid-state) disk drives, the filesystem notifies the underlying
disk of the blocks that it is no longer using. The notification
allows the drive to avoid saving these blocks when it needs to
flash (zero out) one of its flash pages. These notifications of
no-longer-being-used blocks are referred to as TRIM notifications.
In FreeBSD these TRIM notifications are sent from the filesystem
to the drive using the BIO_DELETE command.
Until now, the filesystem would send a separate message to the drive
for each block of the file that was deleted. Each Gigabyte of file
size resulted in over 3000 TRIM messages being sent to the drive.
This burst of messages can overwhelm the drive's task queue causing
multiple second delays for read and write requests.
This implementation collects runs of contiguous blocks in the file
and then consolodates them into a single BIO_DELETE command to the
drive. The BIO_DELETE command describes the run of blocks as a
single large block being deleted. Each Gigabyte of file size can
result in as few as two BIO_DELETE commands and is typically less
than ten. Though these larger BIO_DELETE commands take longer to
run, they do not clog the drive task queue, so read and write
commands can intersperse effectively with them.
Though this new feature has been throughly reviewed and tested, it
is being added disabled by default so as to minimize the possibility
of disrupting the upcoming 12.0 release. It can be enabled by running
``sysctl vfs.ffs.dotrimcons=1''. Users are encouraged to test it.
If no problems arise, we will consider requesting that it be enabled
by default for 12.0.
Reviewed by: kib
Tested by: Peter Holm
Sponsored by: Netflix
driven by problems found with the algorithms being tested for TRIM
consolodation.
Reported by: Peter Holm
Suggested by: kib
Reviewed by: kib
Sponsored by: Netflix
