Commit Graph

360 Commits

Author SHA1 Message Date
Kyle Evans
1b50b999f9 tty: implement TIOCNOTTY
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
2019-11-30 20:10:50 +00:00
Mateusz Guzik
a02cab334c 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
2019-11-30 16:46:19 +00:00
Mateusz Guzik
1fccb43c39 vfs: change si_usecount management to count used vnodes
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
2019-11-20 12:05:59 +00:00
Mateusz Guzik
4c9ba39aea devfs: use MNTK_NOMSYNC
Reviewed by:	kib
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D22009
2019-10-13 15:41:47 +00:00
Konstantin Belousov
e3fdd051f9 devfs_vptocnp(): correct the component name when node is not at top.
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
2019-10-11 18:41:24 +00:00
Mateusz Guzik
559ac49d41 devfs: add root vnode caching
See r353150.

Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D21646
2019-10-06 22:16:55 +00:00
Mateusz Guzik
dfa8dae493 devfs: plug redundant bwillwrite avoidance
vn_write already checks for vnode type to see if bwillwrite should be called.

This effectively reverts r244643.

Reviewed by:	kib
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D21905
2019-10-05 17:44:33 +00:00
Konstantin Belousov
6470c8d3db Rework v_object lifecycle for vnodes.
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
2019-08-29 07:50:25 +00:00
Mark Johnston
918988576c Avoid relying on header pollution from sys/refcount.h.
MFC after:	3 days
Sponsored by:	The FreeBSD Foundation
2019-07-29 20:26:01 +00:00
Conrad Meyer
e2e050c8ef Extract eventfilter declarations to sys/_eventfilter.h
This allows replacing "sys/eventfilter.h" includes with "sys/_eventfilter.h"
in other header files (e.g., sys/{bus,conf,cpu}.h) and reduces header
pollution substantially.

EVENTHANDLER_DECLARE and EVENTHANDLER_LIST_DECLAREs were moved out of .c
files into appropriate headers (e.g., sys/proc.h, powernv/opal.h).

As a side effect of reduced header pollution, many .c files and headers no
longer contain needed definitions.  The remainder of the patch addresses
adding appropriate includes to fix those files.

LOCK_DEBUG and LOCK_FILE_LINE_ARG are moved to sys/_lock.h, as required by
sys/mutex.h since r326106 (but silently protected by header pollution prior
to this change).

No functional change (intended).  Of course, any out of tree modules that
relied on header pollution for sys/eventhandler.h, sys/lock.h, or
sys/mutex.h inclusion need to be fixed.  __FreeBSD_version has been bumped.
2019-05-20 00:38:23 +00:00
Mark Johnston
6d2e2df764 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
2018-11-23 22:24:59 +00:00
Konstantin Belousov
1c4ca77890 Add d_off support for multiple filesystems.
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
2018-11-14 14:18:35 +00:00
Brooks Davis
ed34a7fcf2 Move 32-bit compat support for FIODGNAME to the right place.
ioctl(2) commands only have meaning in the context of a file descriptor
so translating them in the syscall layer is incorrect.

The new handler users an accessor to retrieve/construct a pointer from
the last member of the passed structure and relies on type punning to
access the other member which requires no translation.

Unlike r339174 this change supports both places FIODGNAME is handled.

Reviewed by:	kib
Obtained from:	CheriBSD
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D17475
2018-10-26 17:59:25 +00:00
Brooks Davis
9bc603bd20 Revert r339174: Move 32-bit compat support for FIODGNAME to the right place.
A case was missed in this commit which breaks sshing into a 32-bit sshd
on a 64-bit system.

Approved by:	re (gjb)
2018-10-04 23:55:03 +00:00
Brooks Davis
23f2e22802 Move 32-bit compat support for FIODGNAME to the right place.
ioctl(2) commands only have meaning in the context of a file descriptor
so translating them in the syscall layer is incorrect.

The new handler users an accessor to retrieve/construct a pointer from
the last member of the passed structure and relies on type punning to
access the other member which requires no translation.

Reviewed by:	kib
Approved by:	re (rgrimes, gjb)
Obtained from:	CheriBSD
Sponsored by:	DARPA, AFRL
Differential Review:	https://reviews.freebsd.org/D17388
2018-10-03 20:39:48 +00:00
Jamie Gritton
0e5c6bd436 Make it easier for filesystems to count themselves as jail-enabled,
by doing most of the work in a new function prison_add_vfs in kern_jail.c
Now a jail-enabled filesystem need only mark itself with VFCF_JAIL, and
the rest is taken care of.  This includes adding a jail parameter like
allow.mount.foofs, and a sysctl like security.jail.mount_foofs_allowed.
Both of these used to be a static list of known filesystems, with
predefined permission bits.

Reviewed by:	kib
Differential Revision:	D14681
2018-05-04 20:54:27 +00:00
Brooks Davis
6469bdcdb6 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
2018-04-06 17:35:35 +00:00
John Baldwin
f6e25ec77c Report INT_MAX for LINK_MAX for devfs' VOP_PATHCONF().
devfs uses int's for link counts internally and already reports the the
full link count via stat() post ino64.

Sponsored by:	Chelsio Communications
2017-12-19 20:07:57 +00:00
John Baldwin
418e621276 Handle _PC_FILESIZEBITS and _PC_SYMLINK_MAX for devfs' VOP_PATHCONF().
MFC after:	1 month
Sponsored by:	Chelsio Communications
2017-12-19 19:53:34 +00:00
John Baldwin
599afe53a8 Move NAME_MAX, LINK_MAX, and CHOWN_RESTRICTED out of vop_stdpathconf().
Having all filesystems fall through to default values isn't always correct
and these values can vary for different filesystem implementations.  Most
of these changes just use the existing default values with a few exceptions:
- Don't report CHOWN_RESTRICTED for ZFS since it doesn't do the exact
  permissions check this claims for chown().
- Use NANDFS_NAME_LEN for NAME_MAX for nandfs.
- Don't report a LINK_MAX of 0 on smbfs.  Now fail with EINVAL to
  indicate hard links aren't supported.

Requested by:	bde (though perhaps not this exact implementation)
Reviewed by:	kib (earlier version)
MFC after:	1 month
Sponsored by:	Chelsio Communications
2017-12-19 19:51:36 +00:00
Konstantin Belousov
833429229a In devfs_lookupx() dotdot lookup case, avoid dereferencing
dvp->v_mount after dvp is unlocked.

The vnode might be reclaimed after unlock, so v_mount becomes NULL.
Cache the struct mount pointer before the unlock, the struct is
type-stable.

Note that devfs_allocv() reads mp->mnt_data but does not operate on it
further when dirent is doomed.  The unmount cannot proceed until all
dirents are reclaimed.

Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2017-12-14 13:41:11 +00:00
Emmanuel Vadot
38c9c65ee4 r326394 is calling malloc with M_WAITOK under a lock, revert for now
Reported by:	andrew
2017-11-30 14:06:54 +00:00
Emmanuel Vadot
31e8b07376 devfs: Avoid a malloc/free if we just need to increment the refcount
MFC after:	1 week
Sponsored by:	Gandi.net
2017-11-30 12:38:42 +00:00
Pedro F. Giffuni
d63027b668 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.
2017-11-27 15:15:37 +00:00
John Baldwin
e1d15b892a Only handle _PC_MAX_CANON, _PC_MAX_INPUT, and _PC_VDISABLE for TTY devices.
Move handling of these three pathconf() variables out of vop_stdpathconf()
and into devfs_pathconf() as TTY devices can only be devfs files.  In
addition, only return settings for these three variables for devfs devices
whose device switch has the D_TTY flag set.

Discussed with:	bde, kib
Sponsored by:	Chelsio Communications
2017-09-21 23:05:32 +00:00
Konstantin Belousov
6992112349 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
2017-05-23 09:29:05 +00:00
Edward Tomasz Napierala
1a2dbd1aa3 Simplify devfs_fsync() by removing it. This might also be a minor
optimization, as vn_isdisk() needs to lock a global mutex.

Reviewed by:	imp
Tested by:	pho
MFC after:	2 weeks
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D9628
2017-02-20 16:18:33 +00:00
Konstantin Belousov
ecc6c515ab Apply noexec mount option for mmap(PROT_EXEC).
Right now the noexec mount option disallows image activators to try
execve the files on the mount point.  Also, after r127187, noexec
also limits max_prot map entries permissions for mappings of files
from such mounts, but not the actual mapping permissions.

As result, the API behaviour is inconsistent.  The files from noexec
mount can be mapped with PROT_EXEC, but if mprotect(2) drops execution
permission, it cannot be re-enabled later.  Make this consistent
logically and aligned with behaviour of other systems, by disallowing
PROT_EXEC for mmap(2).

Note that this change only ensures aligned results from mmap(2) and
mprotect(2), it does not prevent actual code execution from files
coming from noexec mount.  Such files can always be read into
anonymous executable memory and executed from there.

Reported by:	shamaz.mazum@gmail.com
PR:	217062
Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2017-02-19 20:51:04 +00:00
Konstantin Belousov
cf53034fc7 Minor style fixes.
Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
2017-02-16 06:31:36 +00:00
Edward Tomasz Napierala
a3b4ab9116 Change the "devfs_fsync: vop_stdfsync failed" from panic to a printf.
It's not a proper fix, but should be better than what we have now.
Since it got broken some six months ago it results in an incredibly
annoying and trivially reproducible panic every time eg an USB disk
gets disconnected.

MFC after:	2 weeks
Sponsored by:	DARPA, AFRL
2017-02-15 16:52:21 +00:00
Konstantin Belousov
584b675ed6 Hide the boottime and bootimebin globals, provide the getboottime(9)
and getboottimebin(9) KPI. Change consumers of boottime to use the
KPI.  The variables were renamed to avoid shadowing issues with local
variables of the same name.

Issue is that boottime* should be adjusted from tc_windup(), which
requires them to be members of the timehands structure.  As a
preparation, this commit only introduces the interface.

Some uses of boottime were found doubtful, e.g. NLM uses boottime to
identify the system boot instance.  Arguably the identity should not
change on the leap second adjustment, but the commit is about the
timekeeping code and the consumers were kept bug-to-bug compatible.

Tested by:	pho (as part of the bigger patch)
Reviewed by:	jhb (same)
Discussed with:	bde
Sponsored by:	The FreeBSD Foundation
MFC after:	1 month
X-Differential revision:	https://reviews.freebsd.org/D7302
2016-07-27 11:08:59 +00:00
Conrad Meyer
af326ace9d devfs: Move most ioctl logic down to vnode layer
Devfs' file layer ioctl is now just a thin shim around the vnode layer.

Reviewed by:	kib
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D7286
2016-07-25 16:28:02 +00:00
Konstantin Belousov
2d5bba3ae3 Another follow-up to r291460. Only access vp->v_rdev for VCHR vnodes
in devfs_reclaim().

Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
Approved by:	re (gjb)
MFC after:	1 week
2016-06-15 15:55:14 +00:00
Konstantin Belousov
ae40237874 Remove zero assignments in the cdev allocator. cdp memory is
requested with M_ZERO.

Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2016-05-21 09:55:32 +00:00
Pedro F. Giffuni
b114da42af sys/devfs: unsign an index to prevent signed integer overflow.
cdp_maxdirent in struct:cdev_priv is of type u_int.  Use the same
type for the corresponding index in devfs_revoke().

MFC after:	1 week
2016-04-28 02:39:43 +00:00
Konstantin Belousov
1a2dd035fb 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
2016-01-22 20:30:51 +00:00
Konstantin Belousov
aeace3c33c Assert that the linkage between struct cdev_privdata and and struct
file is consistent.

Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2016-01-17 08:34:35 +00:00
Konstantin Belousov
a53b7c692d Make devfs_fpdrop() static. It was not a public KPI, and it has no
reason to remain exported for some time.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2016-01-13 14:03:06 +00:00
Konstantin Belousov
fb57d63e47 Hide transient EBADF errors caused by the parallel revoke(2) or forced
unmount of devfs mounts, by restarting the failed syscall.

When restarted, failing syscalls eventually either stop finding the
node and returning ENOENT, or the vnode op vectors finally transition
to the deadfs vop.  The later return EIO or other error, more
appropriate for the operation.

Submitted by:	bde
Tested by:	pho
MFC after:	3 weeks
2016-01-02 20:29:28 +00:00
Konstantin Belousov
d52aff3c7a Minor style cleanup.
Submitted by:	bde
MFC after:	1 week
2016-01-01 15:48:48 +00:00
Konstantin Belousov
cccac8a1ef Make it possible for the cdevsw d_close() driver method to detect last
close and close due to revoke(2)-like operation.

A new FLASTCLOSE flag indicates that this is last close.  FREVOKE is
set for revokes, and FNONBLOCK is also set, same as is already done
for VOP_CLOSE() call from vgonel().

The flags reuse user open(2) flags which are never stored in f_flag,
to not consume bit space in the ABI visible way.  Assert this with the
static check.

Requested and reviewed by:	bde
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2015-12-22 20:37:34 +00:00
Konstantin Belousov
b63d070ad1 Keep devfs mount locked for the whole duration of the devfs_setattr(),
and ensure that our dirent is instantiated.

Reported and tested by:	bde
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2015-12-22 20:22:17 +00:00
John Baldwin
8d7e0f5889 The cdevpriv_dtr_t typedef was not able to be used in a function prototype
like the various d_*_t typedefs since it declared a function pointer rather
than a function.  Add a new d_priv_dtor_t typedef that declares the function
and can be used as a function prototype.  The previous typedef wasn't
useful outside of the cdevpriv implementation, so retire it.

The name d_priv_dtor_t was chosen to be more consistent with cdev methods
since it is commonly used in place of d_close_t even though it is not a
direct pointer in struct cdevsw.

Reviewed by:	kib, imp
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D4340
2015-12-02 18:27:30 +00:00
Edward Tomasz Napierala
643e5ec210 Make it possible to forcibly unmount devfs.
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
2015-08-24 14:04:44 +00:00
Edward Tomasz Napierala
6e572e084b After r286237 it should be fine to call vgone(9) on a busy GEOM vnode;
remove KASSERT that would prevent forced devfs unmount from working.

MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
2015-08-23 14:53:54 +00:00
John Baldwin
fada4adf95 The changes that introduced fo_mmap() treated all character device
mappings as if MAP_SHARED was always present since in general MAP_PRIVATE
is not permitted for character devices.  However, there is one exception
in that MAP_PRIVATE mappings are permitted for /dev/zero.

Only require a writable file descriptor (FWRITE) for shared, writable
mappings of character devices.  vm_mmap_cdev() will reject any private
mappings for other devices.

Reviewed by:	kib
Reported by:	sbruno (broke qemu cross-builds), peter
Differential Revision:	https://reviews.freebsd.org/D3316
2015-08-06 16:50:37 +00:00
John Baldwin
7077c42623 Add a new file operations hook for mmap operations. File type-specific
logic is now placed in the mmap hook implementation rather than requiring
it to be placed in sys/vm/vm_mmap.c.  This hook allows new file types to
support mmap() as well as potentially allowing mmap() for existing file
types that do not currently support any mapping.

The vm_mmap() function is now split up into two functions.  A new
vm_mmap_object() function handles the "back half" of vm_mmap() and accepts
a referenced VM object to map rather than a (handle, handle_type) tuple.
vm_mmap() is now reduced to converting a (handle, handle_type) tuple to a
a VM object and then calling vm_mmap_object() to handle the actual mapping.
The vm_mmap() function remains for use by other parts of the kernel
(e.g. device drivers and exec) but now only supports mapping vnodes,
character devices, and anonymous memory.

The mmap() system call invokes vm_mmap_object() directly with a NULL object
for anonymous mappings.  For mappings using a file descriptor, the
descriptors fo_mmap() hook is invoked instead.  The fo_mmap() hook is
responsible for performing type-specific checks and adjustments to
arguments as well as possibly modifying mapping parameters such as flags
or the object offset.  The fo_mmap() hook routines then call
vm_mmap_object() to handle the actual mapping.

The fo_mmap() hook is optional.  If it is not set, then fo_mmap() will
fail with ENODEV.  A fo_mmap() hook is implemented for regular files,
character devices, and shared memory objects (created via shm_open()).

While here, consistently use the VM_PROT_* constants for the vm_prot_t
type for the 'prot' variable passed to vm_mmap() and vm_mmap_object()
as well as the vm_mmap_vnode() and vm_mmap_cdev() helper routines.
Previously some places were using the mmap()-specific PROT_* constants
instead.  While this happens to work because PROT_xx == VM_PROT_xx,
using VM_PROT_* is more correct.

Differential Revision:	https://reviews.freebsd.org/D2658
Reviewed by:	alc (glanced over), kib
MFC after:	1 month
Sponsored by:	Chelsio
2015-06-04 19:41:15 +00:00
Konstantin Belousov
bda2eb9ae8 Refine r280308. Do not completely disable timestamping of devfs nodes
on reads or writes, the time marks are used to display idle time by
w(1) [1].  Instead, use vfs.devfs.dotimes as the selector of default
precision vs. using time_second.  The later gives seconds precision,
which is good enough for the purpose.

Note that timestamp updates are unlocked and the updates itself, as
well as the check in devfs_timestamp, are non-atomic.

Noted by:	truckman [1]
Reviewed by:	bde
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2015-04-01 08:25:40 +00:00
Xin LI
4f9343fc7c 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
2015-03-21 01:14:11 +00:00
Konstantin Belousov
08189ed667 The VNASSERT in vflush() FORCECLOSE case is trying to panic early to
prevent errors from yanking devices out from under filesystems.  Only
care about special vnodes on devfs, special nodes on other kinds of
filesystems do not have special properties.

Sponsored by:  EMC / Isilon Storage Division
Submitted by:   Conrad Meyer
MFC after:	1 week
2015-02-27 16:43:50 +00:00