Introduce two helpers, the more general SYSCTL_SIZEOF() and
a struct-specific one SYSCTL_SIZEOF_STRUCT() which prepends 'struct' in
the description and in the use of sizeof() but uses the raw structure
name as the knob's name. The size of the object/structure is exported
under 'debug.sizeof'.
Existing knobs under 'debug.sizeof' were all converted to use the
helpers.
Add a note before the helpers discouraging the introduction of new
leaves for ad-hoc reasons. List alternative means for developers to
obtain the size of arbitrary kernel structures easily (thanks to markj@
for providing these).
No functional change (intended).
Reviewed by: kib, markj
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D50121
(cherry picked from commit 713abc9880aabe0ff924ff644bceb6ff404ed3cd)
(cherry picked from commit efce9f8a510b60736994e50288b78fc7b32b5d90)
Approved by: re (cperciva)
Otherwise we end up searching for a device using an uninitialized key,
tripping up KMSAN.
MFC after: 2 weeks
(cherry picked from commit 48d6b52add36cc09e7fb1fbec44ab66c0742f320)
The MNT_IGNORE flag can be used to mark certain filesystem mounts so
that utilities such as df(1) and mount(8) can filter out those mounts by
default. This can be used, for instance, to reduce the noise from
running container workloads inside jails which often have at least three
and sometimes as many as ten mounts per container.
The flag is supplied by the nmount(2) system call and is recorded so
that it can be reported by statfs(2). Unfortunately several filesystems
override the default behaviour and mask out the flag, defeating its
purpose. This change preserves the MNT_IGNORE flag for those filesystems
so that it can be reported correctly.
MFC after: 1 week
(cherry picked from commit b5c4616582cebdcf4dee909a3c2f5b113c4ae59e)
It's possible for misuse of cdev KPIs or for bugs in devfs itself to
result in e.g. a cdev object's container being freed while still on the
global list used to populate each devfs mount; see PR 273418 for a
recent example.
Since a node may be marked inactive well before it is reaped from the
list, add a new flag solely to track list membership, and employ it in
some basic list integrity assertions to catch bad actors.
Discussed with: kib, mjg
(cherry picked from commit 67864268da53b792836f13be10299de8cd62997e)
The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.
Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix
The pseudo file systems (devfs, fdescfs, procfs, etc.) report total
and available blocks and inodes despite being synthetic with no
underlying storage device to which those values could be applied.
The current code of these file systems tends to report a fixed number
of total blocks but no free blocks, and in the case of procfs,
libprocfs, linsysfs also no free inodes.
This can be irritating in e.g. the "df" output, since 100% of the
resources seem to be in use, but it can also create warnings in
monitoring tools used for capacity management.
This patch makes these file systems return the same value for the
total and free parameters, leading to 0% in use being displayed by
"df". Since there is no resource that can be exhausted, this appears
to be a sensible result.
Reviewed by: mckusick
Differential Revision: https://reviews.freebsd.org/D39442
To quote from a comment above vput_final:
<quote>
* XXX Some filesystems pass in an exclusively locked vnode and strongly depend
* on the lock being held all the way until VOP_INACTIVE. This in particular
* happens with UFS which adds half-constructed vnodes to the hash, where they
* can be found by other code.
</quote>
As is there is no mechanism which allows filesystems to denote that a
vnode is fully initialized, consequently problems like the above are
only found the hard way(tm).
Add rudimentary support for state transitions, which in particular allow
to assert the vnode is not legally unlocked until its fate is decided
(either construction finishes or vgone is called to abort it).
The new field lands in a 1-byte hole, thus it does not grow the struct.
Bump __FreeBSD_version to 1400077
Reviewed by: kib (previous version)
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D37759
This removes some of the complexity needed to maintain HASBUF and
allows for removing injecting SAVENAME by filesystems.
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D36542
It is only ever xlocked in drain_dev_clone_events and the only consumer of
that routine does not need it -- eventhandler code already makes sure the
relevant callback is no longer running.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D36268
Also remove once-used functions to clean up after failed insmntque1(),
which were destructor callbacks in previous life.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D34071
I was somehow convinced that insmntque calls insmntque1 with a NULL
destructor. Unfortunately this worked well enough to not immediately
blow up in simple testing.
Keep not using the destructor in previously patched filesystems though
as it avoids unnecessary casts.
Noted by: kib
Reported by: pho
This avoids needing to inspect the mount point every time.
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D33125
devvn_refthread() will initialize *devp only if it succeeds, so check for
success before comparing with fp->f_data. Other devvn_refthread()
callers are careful to do this.
Reported by: KMSAN
Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30068
Make sys/buf.h, sys/pipe.h, sys/fs/devfs/devfs*.h headers usable in
userspace, assuming that the consumer has an idea what it is for.
Unhide more material from sys/mount.h and sys/ufs/ufs/inode.h,
sys/ufs/ufs/ufsmount.h for consumption of userspace tools, with the
same caveat.
Remove unacceptable hack from usr.sbin/makefs which relied on sys/buf.h
being unusable in userspace, where it override struct buf with its own
definition. Instead, provide struct m_buf and struct m_vnode and adapt
code to use local variants.
Reviewed by: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D28679
Before r332974 the old code would sometimes cause a rare lock order
reversal against pagequeue, which looked roughly like this:
witness_checkorder()
__mtx_lock-flags()
vm_page_alloc()
uma_small_alloc()
keg_alloc_slab()
keg_fetch-slab()
zone_fetch-slab()
zone_import()
zone_alloc_bucket()
uma_zalloc_arg()
bucket_alloc()
uma_zfree_arg()
free()
devfs_metoo()
devfs_populate_loop()
devfs_populate()
devfs_rioctl()
VOP_IOCTL_APV()
VOP_IOCTL()
vn_ioctl()
fo_ioctl()
kern_ioctl()
sys_ioctl()
Since r332974 the original problem no longer exists, but it still
makes sense to move things out of the - often congested - lock.
Reviewed By: kib, markj
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D27334
The conversion was largely mechanical: sed(1) with:
-e 's|mtx_assert(&devmtx, MA_OWNED)|dev_lock_assert_locked()|g'
-e 's|mtx_assert(&devmtx, MA_NOTOWNED)|dev_lock_assert_unlocked()|g'
The definitions of these abstractions in fs/devfs/devfs_int.h are the
only non-mechanical change.
No functional change.
This removes a lot of special casing from the VFS layer.
Reviewed by: kib (previous version)
Tested by: pho (previous version)
Differential Revision: https://reviews.freebsd.org/D25612
For software like PostgreSQL and SQLite that sometimes reads sequentially
while also writing sequentially some distance behind with interleaved
syscalls on the same fd, performance is better on UFS if we do
sequential access heuristics separately for reads and writes.
Patch originally by Andrew Gierth in 2008, updated and proposed by me with
his permission.
Reviewed by: mjg, kib, tmunro
Approved by: mjg (mentor)
Obtained from: Andrew Gierth <andrew@tao11.riddles.org.uk>
Differential Revision: https://reviews.freebsd.org/D25024
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
O_SEARCH is defined by POSIX [0] to open a directory for searching, skipping
permissions checks on the directory itself after the initial open(). This is
close to the semantics we've historically applied for O_EXEC on a directory,
which is UB according to POSIX. Conveniently, O_SEARCH on a file is also
explicitly undefined behavior according to POSIX, so O_EXEC would be a fine
choice. The spec goes on to state that O_SEARCH and O_EXEC need not be
distinct values, but they're not defined to be the same value.
This was pointed out as an incompatibility with other systems that had made
its way into libarchive, which had assumed that O_EXEC was an alias for
O_SEARCH.
This defines compatibility O_SEARCH/FSEARCH (equivalent to O_EXEC and FEXEC
respectively) and expands our UB for O_EXEC on a directory. O_EXEC on a
directory is checked in vn_open_vnode already, so for completeness we add a
NOEXECCHECK when O_SEARCH has been specified on the top-level fd and do not
re-check that when descending in namei.
[0] https://pubs.opengroup.org/onlinepubs/9699919799/
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D23247
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
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
Generally, it's preferred that an application fork/setsid if it doesn't want
to keep its controlling TTY, but it could be that a debugger is trying to
steal it instead -- so it would hook in, drop the controlling TTY, then do
some magic to set things up again. In this case, TIOCNOTTY is quite handy
and still respected by at least OpenBSD, NetBSD, and Linux as far as I can
tell.
I've dropped the note about obsoletion, as I intend to support TIOCNOTTY as
long as it doesn't impose a major burden.
Reviewed by: bcr (manpages), kib
Differential Revision: https://reviews.freebsd.org/D22572
This allows bumping threadcount without taking the global devmtx lock.
In particular this eliminates contention on said lock while using bhyve
with multiple vms.
Reviewed by: kib
Tested by: markj
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D22548
Currently si_usecount is effectively a sum of usecounts from all associated
vnodes. This is maintained by special-casing for VCHR every time usecount is
modified. Apart from complicating the code a little bit, it has a scalability
impact since it forces a read from a cacheline shared with said count.
There are no consumers of the feature in the ports tree. In head there are only
2: revoke and devfs_close. Both can get away with a weaker requirement than the
exact usecount, namely just the count of active vnodes. Changing the meaning to
the latter means we only need to modify it on 0<->1 transitions, avoiding the
check plenty of times (and entirely in something like vrefact).
Reviewed by: kib, jeff
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D22202
Node' cdp.si_name is the full path as provided by make_dev(9), it
should not be returned by VOP_VPTOCNP() when only the last component
is requested. Use the dirent entry instead.
With this note, handling of VDIR and VCHR nodes only differs in
handling of root vnode, which simplifies and unifies the logic.
Reported by: Li, Zhichao1 <Zhichao_Li1@Dell.com>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
