if uio->uio_offset != -1. This fixes a problem with aio_read/write
and permits a straightforward implementation of pread/pwrite.
PR: kern/8669
Submitted by: John Plevyak <jplevyak@inktomi.com>
Reviewed by: Matthew Dillon <dillon@apollo.backplane.com>
kern.chroot_allow_open_directories = 0
chroot(2) fails if there are open directories.
kern.chroot_allow_open_directories = 1 (default)
chroot(2) fails if there are open directories and the process
is subject of a previous chroot(2).
kern.chroot_allow_open_directories = anything else
filedescriptors are not checked. (old behaviour).
I'm very interested in reports about software which breaks when
running with the default setting.
space. When doing this, it is possible to for another process to attempt
to get an exclusive lock on the vnode and deadlock the mmap/read
combination when the uiomove() call tries to obtain a second
shared lock on the vnode. There is still a potential deadlock
situation with write()/mmap().
Submitted by: Matt Dillon <dillon@freebsd.org>
Reviewed by: Luoqi Chen <luoqi@freebsd.org>
Delimmitted by tag PRE_MATT_MMAP_LOCK and POST_MATT_MMAP_LOCK
in kern/kern_lock.c kern/kern_subr.c
including alan, john, me, luoqi, and kirk
Submitted by: Matt Dillon <dillon@frebsd.org>
This change implements a relatively sophisticated fix to getnewbuf().
There were two problems with getnewbuf(). First, the writerecursion
can lead to a system stack overflow when you have NFS and/or VN
devices in the system. Second, the free/dirty buffer accounting was
completely broken. Not only did the nfs routines blow it trying to
manually account for the buffer state, but the accounting that was
done did not work well with the purpose of their existance: figuring
out when getnewbuf() needs to sleep.
The meat of the change is to kern/vfs_bio.c. The remaining diffs are
all minor except for NFS, which includes both the fixes for bp
interaction AND fixes for a 'biodone(): buffer already done' lockup.
Sys/buf.h also contains a chaining structure which is not used by
this patchset but is used by other patches that are coming soon.
This patch deliniated by tags PRE_MAT_GETBUF and POST_MAT_GETBUF.
(sorry for the missing T matt)
was discarded on every call to calcru(). Hacking on the `switchtime'
global for a related fix in rev.1.38 of kern_resource.c was too fragile
and broke when p_switchtime went away.
PR: 10402
This code is backwards compatible with the older "microkernel" PLL, but
allows ntpd v4 to use nanosecond resolution. Many other improvements.
PPS_SYNC and hardpps() are NOT supported yet.
unregister them after sysuninits when unloading.
* Add code to vfs_register() to set the oid number of vfs sysctls to
the type number of the filesystem.
Reviewed by: bde
to manage their own memory. Tested on my machine (make buildworld).
I've made analogous changes on the alpha, but don't have a machine
to test.
Not-objected-to by: dg, gibbs
numbers as chars or use bogus casts in an attempt to unmisrepresnt
them. In top, don't assume that 0xff is the only negative cpu
number when cpu numbers are (mis)represented.
Higher numbers led to smaller quanta.
In discussion with BDE, change this parameter to be in uSecs
to make it machine independent,
and limit it to non zero multiples of 'tick' (rounding down).
Also make the variabel globally available so that the present function that
returns its value (used for posix scheduling I believe) can go away.
Submitted by: Bruce Evans <bde@freebsd.org>
This produced races resulting in panics and filesystem corruptions
under some circumstances.
Reviewed by: luoqi chen <luoqi@freebsd.org>
Reviewed by: Kirk McKusick <mckusick@mckusick.com>
Submitted by: Matt Dillon <dillon@freebsd.org>
not per-process. Keep it in `switchtime' consistently.
It is now clear that the timestamp is always valid in fork_trampoline()
except when the child is running on a previously idle cpu, which
can only happen if there are multiple cpus, so don't check or set
the timestamp in fork_trampoline except in the (i386) SMP case.
Just remove the alpha code for setting it unconditionally, since
there is no SMP case for alpha and the code had rotted.
Parts reviewed by: dfr, phk
Add d_parms() to {c,b}devsw[]. If non-NULL this function points to
a device routine that will properly fill in the specinfo structure.
vfs_subr.c's checkalias() supplies appropriate defaults. This change
should be fully backwards compatible with existing devices.
often for it to be a good criterion for switching kernel cpu hogs --
it is true after most wakeups. Use the criterion "has been running
for >= 2 quanta" instead.
in "src/sys/sys/param.h".
Fix the ELF image activator so that it can handle dynamic linkers
which are executables linked at a fixed address. This improves
compliance with the ABI spec, and it opens the door to possibly
better dynamic linker performance in the future. I've experimented
a bit with a fixed-address dynamic linker, and it works fine. But
I don't have any measurements yet to determine whether it's
worthwhile.
Also, remove a few calculations that were never used for anything.
I will increment __FreeBSD_version, since this adds a new capability
to the kernel that the dynamic linker might some day rely upon.
being loaded twice. It used rindex() to strip the pathname but failed
to account for the fact that rindex() will return a pointer to the '/',
not the first character of the filename.
Submitted by: Nick Hibma <hibma@skylink.it>
is the preparation step for moving pmap storage out of vmspace proper.
Reviewed by: Alan Cox <alc@cs.rice.edu>
Matthew Dillion <dillon@apollo.backplane.com>
complaints about ps_refcnt greater than two when we try to fork() a
kthread from proc0 with RFSIGSHARE flag set.
Noticed by: Tor Egge <tegge@fast.no>
Reviewed by: Richard Seaman, Jr. <dick@tar.com>
This makes it possible to change the sysctl tree at runtime.
* Change KLD to find and register any sysctl nodes contained in the loaded
file and to unregister them when the file is unloaded.
Reviewed by: Archie Cobbs <archie@whistle.com>,
Peter Wemm <peter@netplex.com.au> (well they looked at it anyway)
