devfs(4): defer freeing until we drop devmtx ("cdev")

Before r332974 the old code would sometimes cause a rare lock order
reversal against pagequeue, which looked roughly like this:

witness_checkor

devfs(4): defer freeing until we drop devmtx ("cdev")

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

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fs: clean up empty lines in .c and .h files

devfs: Abstract locking assertions

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

devfs: Abstract locking assertions

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.

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devfs: bool -> int

Fixes buildworld after r364069

devfs: save on spurious relocking for devfs_populate

Tested by: pho

Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many)

r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly mark

Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many)

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

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vfs: drop the mostly unused flags argument from VOP_UNLOCK

Filesystems which want to use it in limited capacity can employ the
VOP_UNLOCK_FLAGS macro.

Reviewed by: kib (previous version)
Differenti

vfs: drop the mostly unused flags argument from VOP_UNLOCK

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

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devfs: introduce a per-dev lock to protect ->si_devsw

This allows bumping threadcount without taking the global devmtx lock.

In particular this eliminates contention on said lock while using bhyve

devfs: introduce a per-dev lock to protect ->si_devsw

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

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Ensure that directory entry padding bytes are zeroed.

Directory entries must be padded to maintain alignment; in many
filesystems the padding was not initialized, resulting in stack
memory being cop

Ensure that directory entry padding bytes are zeroed.

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

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Move most of the contents of opt_compat.h to opt_global.h.

opt_compat.h is mentioned in nearly 180 files. In-progress network
driver compabibility improvements may add over 100 more so this is
close

Move most of the contents of opt_compat.h to opt_global.h.

opt_compat.h is mentioned in nearly 180 files. In-progress network
driver compabibility improvements may add over 100 more so this is
closer to "just about everywhere" than "only some files" per the
guidance in sys/conf/options.

Keep COMPAT_LINUX32 in opt_compat.h as it is confined to a subset of
sys/compat/linux/*.c. A fake _COMPAT_LINUX option ensure opt_compat.h
is created on all architectures.

Move COMPAT_LINUXKPI to opt_dontuse.h as it is only used to control the
set of compiled files.

Reviewed by: kib, cem, jhb, jtl
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D14941

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sys/fs: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error

sys/fs: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

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.

show more ...

Commit the 64-bit inode project.

Extend the ino_t, dev_t, nlink_t types to 64-bit ints. Modify
struct dirent layout to add d_off, increase the size of d_fileno
to 64-bits, increase the size of d_na

Commit the 64-bit inode project.

Extend the ino_t, dev_t, nlink_t types to 64-bit ints. Modify
struct dirent layout to add d_off, increase the size of d_fileno
to 64-bits, increase the size of d_namlen to 16-bits, and change
the required alignment. Increase struct statfs f_mntfromname[] and
f_mntonname[] array length MNAMELEN to 1024.

ABI breakage is mitigated by providing compatibility using versioned
symbols, ingenious use of the existing padding in structures, and
by employing other tricks. Unfortunately, not everything can be
fixed, especially outside the base system. For instance, third-party
APIs which pass struct stat around are broken in backward and
forward incompatible ways.

Kinfo sysctl MIBs ABI is changed in backward-compatible way, but
there is no general mechanism to handle other sysctl MIBS which
return structures where the layout has changed. It was considered
that the breakage is either in the management interfaces, where we
usually allow ABI slip, or is not important.

Struct xvnode changed layout, no compat shims are provided.

For struct xtty, dev_t tty device member was reduced to uint32_t.
It was decided that keeping ABI compat in this case is more useful
than reporting 64-bit dev_t, for the sake of pstat.

Update note: strictly follow the instructions in UPDATING. Build
and install the new kernel with COMPAT_FREEBSD11 option enabled,
then reboot, and only then install new world.

Credits: The 64-bit inode project, also known as ino64, started life
many years ago as a project by Gleb Kurtsou (gleb). Kirk McKusick
(mckusick) then picked up and updated the patch, and acted as a
flag-waver. Feedback, suggestions, and discussions were carried
by Ed Maste (emaste), John Baldwin (jhb), Jilles Tjoelker (jilles),
and Rick Macklem (rmacklem). Kris Moore (kris) performed an initial
ports investigation followed by an exp-run by Antoine Brodin (antoine).
Essential and all-embracing testing was done by Peter Holm (pho).
The heavy lifting of coordinating all these efforts and bringing the
project to completion were done by Konstantin Belousov (kib).

Sponsored by: The FreeBSD Foundation (emaste, kib)
Differential revision: https://reviews.freebsd.org/D10439

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Minor style fixes.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days

Remove zero assignments in the cdev allocator. cdp memory is
requested with M_ZERO.

Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

When devfs dirent is freed, a vnode might still keep a pointer to it,
apparently. Interlock and clear the pointer to avoid free memory
dereference.

Submitted by: bde (previous version)
MFC after: 3

When devfs dirent is freed, a vnode might still keep a pointer to it,
apparently. Interlock and clear the pointer to avoid free memory
dereference.

Submitted by: bde (previous version)
MFC after: 3 weeks

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Disable timestamping on devfs read/write operations by default.

Currently we update timestamps unconditionally when doing read or
write operations. This may slow things down on hardware where
readi

Disable timestamping on devfs read/write operations by default.

Currently we update timestamps unconditionally when doing read or
write operations. This may slow things down on hardware where
reading timestamps is expensive (e.g. HPET, because of the default
vfs.timestamp_precision setting is nanosecond now) with limited
benefit.

A new sysctl variable, vfs.devfs.dotimes is added, which can be
set to non-zero value when the old behavior is desirable.

Differential Revision: https://reviews.freebsd.org/D2104
Reported by: Mike Tancsa <mike sentex net>
Reviewed by: kib
Relnotes: yes
Sponsored by: iXsystems, Inc.
MFC after: 2 weeks

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Stop enforcing additional reference on all cdevs, which was introduced
in r277199. Acquire the neccessary reference in delist_dev_locked()
and inform destroy_devl() about it using CDP_UNREF_DTR flag

Stop enforcing additional reference on all cdevs, which was introduced
in r277199. Acquire the neccessary reference in delist_dev_locked()
and inform destroy_devl() about it using CDP_UNREF_DTR flag.

Fix some style nits, add asserts.

Discussed with: hselasky
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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Ignore devfs directory entries for devices either being destroyed or
delisted. The check is racy.

Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Avoid race with "dev_rel()" when using the recently added
"delist_dev()" function. Make sure the character device structure
doesn't go away until the end of the "destroy_dev()" function due to
concur

Avoid race with "dev_rel()" when using the recently added
"delist_dev()" function. Make sure the character device structure
doesn't go away until the end of the "destroy_dev()" function due to
concurrently running cleanup code inside "devfs_populate()".

MFC after: 1 week
Reported by: dchagin@

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Fix multiple incorrect SYSCTL arguments in the kernel:

- Wrong integer type was specified.

- Wrong or missing "access" specifier. The "access" specifier
sometimes included the SYSCTL type, which it

Fix multiple incorrect SYSCTL arguments in the kernel:

- Wrong integer type was specified.

- Wrong or missing "access" specifier. The "access" specifier
sometimes included the SYSCTL type, which it should not, except for
procedural SYSCTL nodes.

- Logical OR where binary OR was expected.

- Properly assert the "access" argument passed to all SYSCTL macros,
using the CTASSERT macro. This applies to both static- and dynamically
created SYSCTLs.

- Properly assert the the data type for both static and dynamic
SYSCTLs. In the case of static SYSCTLs we only assert that the data
pointed to by the SYSCTL data pointer has the correct size, hence
there is no easy way to assert types in the C language outside a
C-function.

- Rewrote some code which doesn't pass a constant "access" specifier
when creating dynamic SYSCTL nodes, which is now a requirement.

- Updated "EXAMPLES" section in SYSCTL manual page.

MFC after: 3 days
Sponsored by: Mellanox Technologies

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Fix long known bug with handling device aliases residing not in devfs root.

Historically creation of device aliases created symbolic links using only
name of target device as a link target, not cons

Fix long known bug with handling device aliases residing not in devfs root.

Historically creation of device aliases created symbolic links using only
name of target device as a link target, not considering current directory.
Fix that by adding number of "../" chunks to the terget device name,
required to get out of the current directory to devfs root first.

MFC after: 1 month

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- Correct mispellings of the word necessary

Submitted by: Christoph Mallon <[email protected]> (via private mail)

Remove M_USE_RESERVE from the devfs cdp allocator, which is one of two
uses of M_USE_RESERVE in the kernel. This allocation is not special.

Reviewed by: alc
Tested by: pho
MFC after: 2 weeks

Merge si_name and __si_namebuf.

The si_name pointer always points to the __si_namebuf member inside the
same object. Remove it and rename __si_namebuf to si_name.

Export devfs inode number allocator for the kernel consumers.

Reviewed by: jhb
MFC after: 2 weeks