to perform an ownership test in revoke(). This is also required for
MAC hooks so that the vnode lock is held during a call to the MAC
framework. Release the lock before calling VOP_REVOKE().
Discussed with: phk, mckusick
o Modify the system call syntax for extattr_{get,set}_{fd,file}() so
as not to use the scatter gather API (which appeared not to be used
by any consumers, and be less portable), rather, accepts 'data'
and 'nbytes' in the style of other simple read/write interfaces.
This changes the API and ABI.
o Modify system call semantics so that extattr_get_{fd,file}() return
a size_t. When performing a read, the number of bytes read will
be returned, unless the data pointer is NULL, in which case the
number of bytes of data are returned. This changes the API only.
o Modify the VOP_GETEXTATTR() vnode operation to accept a *size_t
argument so as to return the size, if desirable. If set to NULL,
the size will not be returned.
o Update various filesystems (pseodofs, ufs) to DTRT.
These changes should make extended attributes more useful and more
portable. More commits to rebuild the system call files, as well
as update userland utilities to follow.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
- Fix null-pointer dereference introduced when snapshotting
was introduced. This occured because unlike the previous code,
vn_start_write() doesn't always return a non-NULL mp, as
filesystems may not support the VOP_GETWRITEMOUNT() call. For
now, rely on two pointers, so that vn_finished_write() works
properly.
- Fix locking problems on exit, introduced at some past time,
some when snapshots came in, where a vnode might not be
unlocked before being vrele'd in various error situations.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
The binary format "bintime" is a 32.64 format, it will go to 64.64
when time_t does.
The bintime format is available to consumers of time in the kernel,
and is preferable where timeintervals needs to be accumulated.
This change simplifies much of the magic math inside the timecounters
and improves the frequency and time precision by a couple of bits.
I have not been able to measure a performance difference which was not
a tiny fraction of the standard deviation on the measurements.
this is a low-functionality change that changes the kernel to access the main
thread of a process via the linked list of threads rather than
assuming that it is embedded in the process. It IS still embeded there
but remove all teh code that assumes that in preparation for the next commit
which will actually move it out.
Reviewed by: peter@freebsd.org, gallatin@cs.duke.edu, benno rice,
- Create a private list of active pmaps rather than abusing the list of all
processes when we need to look up pmaps. The process list needs a sx lock
and we can't be getting sx locks in the middle of cpu_switch()
(pmap_activate() can call pmap_get_asn() from cpu_switch()). Instead, we
protect the list with a spinlock. This also means the list is shorter
since a pmap can be used by more than one process and we could (at least
in thoery) dink with pmap's more than once, but now we only touch each
pmap once when we have to update all of them.
- Wrap pmap_activate()'s code to get a new ASN in an explicit critical section
so that when it is called while doing an exec() we can't get preempted.
- Replace splhigh() in pmap_growkernel() with a critical section to prevent
preemption while we are adjusting the kernel page tables.
- Fixes abuse of PCPU_GET(), which doesn't return an L-value.
- Also adds some slight cleanups to the ASN handling by adding some macros
instead of magic numbers in relation to the ASN and ASN generations.
Reviewed by: dfr
shared.
Also introduce vm_endcopy instead of using pointer tricks when
initializing new vmspaces.
The race occured because of how the reference was utilized:
test vmspace reference,
possibly block,
decrement reference
When sharing a vmspace between multiple processes it was possible
for two processes exiting at the same time to test the reference
count, possibly block and neither one free because they wouldn't
see the other's update.
Submitted by: green
HZ=BIGNUM will strain the assumptions behind timecounters to the
point where they break.
This may or may not help people seeing microuptime() backwards messages.
Make the global timecounter variable volatile, it makes no difference in
the code GCC generates, but it makes represents the intent correctly.
Thanks to: jdp
MFC after: 2 weeks
call VOP_INACTIVE before placing the vnode back on the free list.
Otherwise there is a race condition on SMP machines between
getnewvnode() locking the vnode to reclaim it and vrele()
locking the vnode to inactivate it. This window of vulnerability
becomes exaggerated in the presence of filesystems that have
been suspended as the inactive routine may need to temporarily
release the lock on the vnode to avoid deadlock with the syncer
process.
threads race for a file slot.
dup2(2) incorrectly assumes that if it needs to grow the ofiles
array that it will get what it wants. This assertion was valid
before we allowed shared filedescriptor tables but is now incorrect.
The assertion can trigger superfolous panics if the thread doing a
dup2 looses a race with another thread while possibly blocked in
the MALLOC call in fdalloc. Another thread may grab the slot we
are requesting which makes fdalloc return something other than what
we asked for, this will triggering the bogus assertion.
MFC after: 2 weeks
Reviewed by: phk
signal trampoline for old signals. The arches that support old signals
currently abuse sigreturn(2) instead. This mainly complicates things
and slightly breaks the the new sigreturn(2).
COMPAT is too limited to support the correct configuration of osigreturn,
and this commit doesn't attempt to fix it; it just moves the bogusness:
osigreturn() must now be provided unconditionally even on arches that
don't really need it; previously it had to be provided under the bogus
condition defined(COMPAT_43).
other threads as well as speed up the interfaces.
To fix the race and accomplish the speedup, remove selholddrop and
pollholddrop. The entire concept is somewhat bogus because holding
the individual struct file pointers offers us no guarantees that
another thread context won't close it on us thereby removing our
access to our own reference.
Selholddrop and pollholddrop also would do multiple locks and unlocks
of mutexes _per-file_ in the fd arrays to be scanned, this needed to
be sped up.
Instead of using selholddrop and pollholddrop, simply hold the
filedesc lock over the selscan and pollscan functions. This should
protect us against close(2)'s on the files as reduce the multiple
lock/unlock pairs per fd into a single lock over the filedesc.
from 1 megabyte of ram per user to 2 megabytes of ram per user, and
reduce the cap from 512 to 384. 512 leaves around 240 MB of KVM available
while 384 leaves 270 MB of KVM available. Available KVM is important
in order to deal with zalloc and kernel malloc area growth.
Reviewed by: mckusick
MFC: either before 4.5 if re's agree, or after 4.5
This allows obtaining crash dumps from the panics occured during late stages
of kernel initialisation before system enters into single-user mode.
MFC after: 2 weeks
replace mutex_lock calls on uidinfo with macro calls:
mtx_lock(&uidp->ui_mtx) -> UIDINFO_LOCK(uidp)
Terry Lambert <tlambert2@mindspring.com> helped with this.
sleeping on a process object but changed the corresponding
wakeup()s to the thread object. The result was that non-raw
aio ops waited for an aio daemon to timeout before action
was taken. Now, we sleep on the thread object.
PR: kern/34016
operation. The vgonel() code has always called vclean() but until we
started proactively freeing vnodes it would never actually be called with
a dirty vnode, so this situation did not occur prior to the vnlru() code.
Now that we proactively free vnodes when kern.maxvnodes is hit, however,
vclean() winds up with work to do and improperly generates the warnings.
Reviewed by: peter
Approved by: re (for MFC)
MFC after: 1 day
seem to be too short for the 500 Mhz DS20 I'm testing on. The rather
arbitrary numbers are rather bogus anyways. We should probably have
variables for these limits that are calibrated in the MD startup code
somehow.
involving file removal or file update were not always being fully
committed to disk. The result was lost files or corrupted file data.
This change ensures that the filesystem is properly synced to disk
before the filesystem is down-graded.
This delta also fixes a long standing bug in which a file open for
reading has been unlinked. When the last open reference to the file
is closed, the inode is reclaimed by the filesystem. Previously,
if the filesystem had been down-graded to read-only, the inode could
not be reclaimed, and thus was lost and had to be later recovered
by fsck. With this change, such files are found at the time of the
down-grade. Normally they will result in the filesystem down-grade
failing with `device busy'. If a forcible down-grade is done, then
the affected files will be revoked causing the inode to be released
and the open file descriptors to begin failing on attempts to read.
Submitted by: "Sam Leffler" <sam@errno.com>
Backout revision 1.56 and 1.57 of fifo_vnops.c.
Introduce a new poll op "POLLINIGNEOF" that can be used to ignore
EOF on a fifo, POLLIN/POLLRDNORM is converted to POLLINIGNEOF within
the FIFO implementation to effect the correct behavior.
This should allow one to view a fifo pretty much as a data source
rather than worry about connections coming and going.
Reviewed by: bde
than necessary.
o Move a rarely-used goto label inside a critical section so that we don't
perform an splnet() for which there is no corresponding splx().
o Remove unnecessary splnet()/splx() around accesses to kaioinfo::kaio_jobdone
in aio_return().
o Use TAILQ_FOREACH for simple cases of iteration over kaioinfo::kaio_jobdone.
Seigo Tanimura (tanimura) posted the initial delta.
I've polished it quite a bit reducing the need for locking and
adapting it for KSE.
Locks:
1 mutex in each filedesc
protects all the fields.
protects "struct file" initialization, while a struct file
is being changed from &badfileops -> &pipeops or something
the filedesc should be locked.
1 mutex in each struct file
protects the refcount fields.
doesn't protect anything else.
the flags used for garbage collection have been moved to
f_gcflag which was the FILLER short, this doesn't need
locking because the garbage collection is a single threaded
container.
could likely be made to use a pool mutex.
1 sx lock for the global filelist.
struct file * fhold(struct file *fp);
/* increments reference count on a file */
struct file * fhold_locked(struct file *fp);
/* like fhold but expects file to locked */
struct file * ffind_hold(struct thread *, int fd);
/* finds the struct file in thread, adds one reference and
returns it unlocked */
struct file * ffind_lock(struct thread *, int fd);
/* ffind_hold, but returns file locked */
I still have to smp-safe the fget cruft, I'll get to that asap.
We calculate a trigger point that both guarentees we will find a
sufficient number of vnodes to recycle and prevents us from recycling
vnodes with lots of resident pages. This particular section of
code is designed to recycle vnodes, not do unnecessary frees of
cached VM pages.
can't acquire the mnt_lock without blocking. Normally non-forced
unmount attempts return EBUSY quickly if any vnodes are active, so
this just extends that behaviour to cover the per-mount mnt_lock
too.
automatically extended to prevent overflow.
* Added sbuf_vprintf(); sbuf_printf() is now just a wrapper around
sbuf_vprintf().
* Include <stdio.h> and <string.h> when building libsbuf to silence
WARNS=4 warnings.
Reviewed by: des
macro. As a result, mandatory signal delivery policies will be
applied consistently across the kernel.
- Note that this subtly changes the protection semantics, and we should
watch out for any resulting breakage. Previously, delivery of SIGIO
in this circumstance was limited to situations where the subject was
privileged, or where one of the subject's (ruid, euid) matched one
of the object's (ruid, euid). In the new scenario, subject (ruid, euid)
are matched against the object's (ruid, svuid), and the object uid's
must be a subset of the subject uid's. Likewise, jail now affects
delivery, and special handling for P_SUGID of the object is present.
This change can always be reversed or tweaked if it proves to disrupt
application behavior substantially.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
authorized based on a subject credential rather than a subject process.
This will permit the same logic to be reused in situations where only
the credential generating the signal is available, such as in the
delivery of SIGIO.
- Because of two clauses, the automatic success against curproc,
and the session semantics for SIGCONT, not all logic can be pushed
into cr_cansignal(), but those cases should not apply for most other
consumers of cr_cansignal().
- This brings the base system inter-process authorization code more
into line with the MAC implementation.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
fifesystem problems could prevent the release from completing and
this could result in init being blocked indefinitely.
This was looked over by Matt ages ago.
Approved by: dillon
SMTX in utils such as ps and top. The KI_CTTY flag was assigned to
kinfo_proc->ki_kiflag rather than or'd into the flag, thus clobbering
any flags set earlier, including KI_MTXBLOCK.
Prodding by: peter
mutex releases to not require flags for the cases when preemption is
not allowed:
The purpose of the MTX_NOSWITCH and SWI_NOSWITCH flags is to prevent
switching to a higher priority thread on mutex releease and swi schedule,
respectively when that switch is not safe. Now that the critical section
API maintains a per-thread nesting count, the kernel can easily check
whether or not it should switch without relying on flags from the
programmer. This fixes a few bugs in that all current callers of
swi_sched() used SWI_NOSWITCH, when in fact, only the ones called from
fast interrupt handlers and the swi_sched of softclock needed this flag.
Note that to ensure that swi_sched()'s in clock and fast interrupt
handlers do not switch, these handlers have to be explicitly wrapped
in critical_enter/exit pairs. Presently, just wrapping the handlers is
sufficient, but in the future with the fully preemptive kernel, the
interrupt must be EOI'd before critical_exit() is called. (critical_exit()
can switch due to a deferred preemption in a fully preemptive kernel.)
I've tested the changes to the interrupt code on i386 and alpha. I have
not tested ia64, but the interrupt code is almost identical to the alpha
code, so I expect it will work fine. PowerPC and ARM do not yet have
interrupt code in the tree so they shouldn't be broken. Sparc64 is
broken, but that's been ok'd by jake and tmm who will be fixing the
interrupt code for sparc64 shortly.
Reviewed by: peter
Tested on: i386, alpha
(There has been some discussion, whether ENOENT or EBADF is more
appropriate. I choose the latter, since the operation is not supported
on the file descriptor at that time, even if it was, immediately before.)
PR: 32681
Reviewed by: dillon, iedowse, ...
Approved by: nectar
MFC after: 3 days
(pending RE approval)
socreate(), rather than getting it implicitly from the thread
argument.
o Make NFS cache the credential provided at mount-time, and use
the cached credential (nfsmount->nm_cred) when making calls to
socreate() on initially connecting, or reconnecting the socket.
This fixes bugs involving NFS over TCP and ipfw uid/gid rules, as well
as bugs involving NFS and mandatory access control implementations.
Reviewed by: freebsd-arch
Remove the explicit call to aio_proc_rundown() from exit1(), instead AIO
will use at_exit(9).
Add functions at_exec(9), rm_at_exec(9) which function nearly the
same as at_exec(9) and rm_at_exec(9), these functions are called
on behalf of modules at the time of execve(2) after the image
activator has run.
Use a modified version of tegge's suggestion via at_exec(9) to close
an exploitable race in AIO.
Fix SYSCALL_MODULE_HELPER such that it's archetecuterally neutral,
the problem was that one had to pass it a paramater indicating the
number of arguments which were actually the number of "int". Fix
it by using an inline version of the AS macro against the syscall
arguments. (AS should be available globally but we'll get to that
later.)
Add a primative system for dynamically adding kqueue ops, it's really
not as sophisticated as it should be, but I'll discuss with jlemon when
he's around.
A [hopefully] conforming style(9) revamp of mb_alloc and related code.
(This was possible due to bde's remarkable patience.)
Submitted by: (in large part) bde
Reviewed by: (the other part) bde
and a generic resource_list_print_type() function to print all resouces
of a certain type in a resource list.
Use ulmin()/ulmax() instead of min()/max() in two places to handle
u_longs correctly.
argument specifying the boundary for the resource allocation.
Use ulmin()/ulmax() instead of min()/max() in some places to correctly
deal with the u_long resource range specifications.
code only passed up the connection to the tcp stack when it was complete,
so it went directly into the so_comp (complete) queue. However, with
accept filters, there is an additional phase before calling it "complete".
Reviewed by: jlemon
and it's associated state variables: icu_lock with the name "icu". This
renames the imen_mtx for x86 SMP, but also uses the lock to protect
access to the 8259 PIC on x86 UP. This also adds an appropriate lock to
the various Alpha chipsets which fixes problems with Alpha SMP machines
dropping interrupts with an SMP kernel.
against VM_WAIT in the pageout code. Both fixes involve adjusting
the lockmgr's timeout capability so locks obtained with timeouts do not
interfere with locks obtained without a timeout.
Hopefully MFC: before the 4.5 release
the shutdown request at reboot/halt time.
Disable the printf 'vnlru process getting nowhere, pausing...' and instead
export the count to the debug.vnlru_nowhere sysctl.
of polling interfaces at the lowest possible priority
(this might result in softnetisr being scheduled, but there is
no risk of livelock because they have a higher priority than
this thread).
by me to make it more efficient. The original code had serious balancing
problems and could also deadlock easily. This code relegates the vnode
reclamation to its own kproc and relaxes the vnode reclamation requirements
to better maintain kern.maxvnodes. This code still doesn't balance as well
as it could, but it does a much better job then the original code.
Approved by: re@freebsd.org
Obtained from: ps, peter, dillon
MFS Assuming: Assuming no problems crop up in Yahoo testing
MFC after: 7 days
remove the check from addupc_task(). It would need sched_lock while
testing the flag anyways.
- Always read sticks while holding sched_lock using a temporary variable
where needed.
- Always init prticks to 0 in ast() to quiet a warning.
- The MD functions critical_enter/exit are renamed to start with a cpu_
prefix.
- MI wrapper functions critical_enter/exit maintain a per-thread nesting
count and a per-thread critical section saved state set when entering
a critical section while at nesting level 0 and restored when exiting
to nesting level 0. This moves the saved state out of spin mutexes so
that interlocking spin mutexes works properly.
- Most low-level MD code that used critical_enter/exit now use
cpu_critical_enter/exit. MI code such as device drivers and spin
mutexes use the MI wrappers. Note that since the MI wrappers store
the state in the current thread, they do not have any return values or
arguments.
- mtx_intr_enable() is replaced with a constant CRITICAL_FORK which is
assigned to curthread->td_savecrit during fork_exit().
Tested on: i386, alpha
The description field is unused in -stable, so the MFC there is equivalent
to a comment. It can be done at any time, i am just setting a reminder
in 45 days when hopefully we are past 4.5-release.
MFC after: 45 days
variables. Use the -d flag in sysctl(8) to see this information.
Possible extensions to sysctl:
+ report variables that do not have a description
+ given a name, report the oid it maps to.
Note to developers: have a look at your code, there are a number of
variables which do not have a description.
Note to developers: do we want this in 4.5 ? It is a very small change
and very useful for documentation purposes.
Suggested by: Orion Hodson
of mi_switch:
- Set the oncpu value for the current thread.
- Always set switchticks, not just in the SMP case.
- Add a KTR entry for fork_exit that is the same as the "new proc"
entry in mi_switch().
- Release sched_lock a bit later like we do with mi_switch().
Non-SMP, i386-only, no polling in the idle loop at the moment.
To use this code you must compile a kernel with
options DEVICE_POLLING
and at runtime enable polling with
sysctl kern.polling.enable=1
The percentage of CPU reserved to userland can be set with
sysctl kern.polling.user_frac=NN (default is 50)
while the remainder is used by polling device drivers and netisr's.
These are the only two variables that you should need to touch. There
are a few more parameters in kern.polling but the default values
are adequate for all purposes. See the code in kern_poll.c for
more details on them.
Polling in the idle loop will be implemented shortly by introducing
a kernel thread which does the job. Until then, the amount of CPU
dedicated to polling will never exceed (100-user_frac).
The equivalent (actually, better) code for -stable is at
http://info.iet.unipi.it/~luigi/polling/
and also supports polling in the idle loop.
NOTE to Alpha developers:
There is really nothing in this code that is i386-specific.
If you move the 2 lines supporting the new option from
sys/conf/{files,options}.i386 to sys/conf/{files,options} I am
pretty sure that this should work on the Alpha as well, just that
I do not have a suitable test box to try it. If someone feels like
trying it, I would appreciate it.
NOTE to other developers:
sure some things could be done better, and as always I am open to
constructive criticism, which a few of you have already given and
I greatly appreciated.
However, before proposing radical architectural changes, please
take some time to possibly try out this code, or at the very least
read the comments in kern_poll.c, especially re. the reason why I
am using a soft netisr and cannot (I believe) replace it with a
simple timeout.
Quick description of files touched by this commit:
sys/conf/files.i386
new file kern/kern_poll.c
sys/conf/options.i386
new option
sys/i386/i386/trap.c
poll in trap (disabled by default)
sys/kern/kern_clock.c
initialization and hardclock hooks.
sys/kern/kern_intr.c
minor swi_net changes
sys/kern/kern_poll.c
the bulk of the code.
sys/net/if.h
new flag
sys/net/if_var.h
declaration for functions used in device drivers.
sys/net/netisr.h
NETISR_POLL
sys/dev/fxp/if_fxp.c
sys/dev/fxp/if_fxpvar.h
sys/pci/if_dc.c
sys/pci/if_dcreg.h
sys/pci/if_sis.c
sys/pci/if_sisreg.h
device driver modifications
When a positively niced process requests a disk I/O, make
it wait for its nice value of ticks before scheduling its
I/O request if there are any other processes with I/O
requests in the disk queue. For all the gory details, see
the ``Running fsck in the Background'' paper in the Usenix
BSDCon 2002 Conference Proceedings, pages 55-64.
commit by Kirk also fixed a softupdates bug that could easily be triggered
by server side NFS.
* An edge case with shared R+W mmap()'s and truncate whereby
the system would inappropriately clear the dirty bits on
still-dirty data. (applicable to all filesystems)
THIS FIX TEMPORARILY DISABLED PENDING FURTHER TESTING.
see vm/vm_page.c line 1641
* The straddle case for VM pages and buffer cache buffers when
truncating. (applicable to NFS client side)
* Possible SMP database corruption due to vm_pager_unmap_page()
not clearing the TLB for the other cpu's. (applicable to NFS
client side but could effect all filesystems). Note: not
considered serious since the corruption occurs beyond the file
EOF.
* When flusing a dirty buffer due to B_CACHE getting cleared,
we were accidently setting B_CACHE again (that is, bwrite() sets
B_CACHE), when we really want it to stay clear after the write
is complete. This resulted in a corrupt buffer. (applicable
to all filesystems but probably only triggered by NFS)
* We have to call vtruncbuf() when ftruncate()ing to remove
any buffer cache buffers. This is still tentitive, I may
be able to remove it due to the second bug fix. (applicable
to NFS client side)
* vnode_pager_setsize() race against nfs_vinvalbuf()... we have
to set n_size before calling nfs_vinvalbuf or the NFS code
may recursively vnode_pager_setsize() to the original value
before the truncate. This is what was causing the user mmap
bus faults in the nfs tester program. (applicable to NFS
client side)
* Fix to softupdates (see ufs/ffs/ffs_inode.c 1.73, commit made
by Kirk).
Testing program written by: Avadis Tevanian, Jr.
Testing program supplied by: jkh / Apple (see Dec2001 posting to freebsd-hackers with Subject 'NFS: How to make FreeBS fall on its face in one easy step')
MFC after: 1 week
always deriving the credential for a newly accepted connection from
the listen socket. Previously, the selection of the credential
depended on the protocol: UNIX domain sockets would use the
connecting process's credential, and protocols supporting a creation
of the socket before the receiving end called accept() would use
the listening socket. After this change, it is always the listening
credential.
Reviewed by: green
