Note that an unload facility should be used to call rm_at_exit() (if
procfs is being loaded as an LKM and is subsequently removed), but it
was non-obvious how to do this in the VFS framework.
Reviewed by: Julian Elischer
procfs/mem file. While this doesn't prevent an unkillable process, it
means that a broken truss prorgam won't do it accidently now (well,
there's a small window of opportunity). Note that this requires the
change to truss I am about to commit.
Ever since I first say the way the mount flags were used I've hated the
fact that modes, and events, internal and exported, and short-term
and long term flags are all thrown together. Finally it's annoyed me enough..
This patch to the entire FreeBSD tree adds a second mount flag word
to the mount struct. it is not exported to userspace. I have moved
some of the non exported flags over to this word. this means that we now
have 8 free bits in the mount flags. There are another two that might
well move over, but which I'm not sure about.
The only user visible change would have been in pstat -v, except
that davidg has disabled it anyhow.
I'd still like to move the state flags and the 'command' flags
apart from each other.. e.g. MNT_FORCE really doesn't have the
same semantics as MNT_RDONLY, but that's left for another day.
it in struct proc instead.
This fixes a boatload of compiler warning, and removes a lot of cruft
from the sources.
I have not removed the /*ARGSUSED*/, they will require some looking at.
libkvm, ps and other userland struct proc frobbing programs will need
recompiled.
in a file. There was a (harmless, I think) off-by-1 error. This
was fixed in ufs long ago (rev.1.21 of ufs_readwrite.c) but not
in cd9660.
cd9660_read() has stagnated in many other ways. It is closer to
the Net/2 ufs_read() (which is was cloned from) than ufs_read()
itself is.
Rename vn_default_error to vop_defaultop all over the place.
Move vn_bwrite from vfs_bio.c to vfs_default.c and call it vop_stdbwrite.
Use vop_null instead of nullop.
Move vop_nopoll from vfs_subr.c to vfs_default.c
Move vop_sharedlock from vfs_subr.c to vfs_default.c
Move vop_nolock from vfs_subr.c to vfs_default.c
Move vop_nounlock from vfs_subr.c to vfs_default.c
Move vop_noislocked from vfs_subr.c to vfs_default.c
Use vop_ebadf instead of *_ebadf.
Add vop_defaultop for getpages on master vnode in MFS.
1. Add defaults for more VOPs
VOP_LOCK vop_nolock
VOP_ISLOCKED vop_noislocked
VOP_UNLOCK vop_nounlock
and remove direct reference in filesystems.
2. Rename the nfsv2 vnop tables to improve sorting order.
1. Remove VOP_UPDATE, it is (also) an UFS/{FFS,LFS,EXT2FS,MFS}
intereface function, and now lives in the ufsmount structure.
2. Remove VOP_SEEK, it was unused.
3. Add mode default vops:
VOP_ADVLOCK vop_einval
VOP_CLOSE vop_null
VOP_FSYNC vop_null
VOP_IOCTL vop_enotty
VOP_MMAP vop_einval
VOP_OPEN vop_null
VOP_PATHCONF vop_einval
VOP_READLINK vop_einval
VOP_REALLOCBLKS vop_eopnotsupp
And remove identical functionality from filesystems
4. Add vop_stdpathconf, which returns the canonical stuff. Use
it in the filesystems. (XXX: It's probably wrong that specfs
and fifofs sets this vop, shouldn't it come from the "host"
filesystem, for instance ufs or cd9660 ?)
5. Try to make system wide VOP functions have vop_* names.
6. Initialize the um_* vectors in LFS.
(Recompile your LKMS!!!)
1. Add new file "sys/kern/vfs_default.c" where default actions for
VOPs go. Implement proper defaults for ABORTOP, BWRITE, LEASE,
POLL, REVOKE and STRATEGY. Various stuff spread over the entire
tree belongs here.
2. Change VOP_BLKATOFF to a normal function in cd9660.
3. Kill VOP_BLKATOFF, VOP_TRUNCATE, VOP_VFREE, VOP_VALLOC. These
are private interface functions between UFS and the underlying
storage manager layer (FFS/LFS/MFS/EXT2FS). The functions now
live in struct ufsmount instead.
4. Remove a kludge of VOP_ functions in all filesystems, that did
nothing but obscure the simplicity and break the expandability.
If a filesystem doesn't implement VOP_FOO, it shouldn't have an
entry for it in its vnops table. The system will try to DTRT
if it is not implemented. There are still some cruft left, but
the bulk of it is done.
5. Fix another VCALL in vfs_cache.c (thanks Bruce!)
1. Use the default function to access all the specfs operations.
2. Use the default function to access all the fifofs operations.
3. Use the default function to access all the ufs operations.
4. Fix VCALL usage in vfs_cache.c
5. Use VOCALL to access specfs functions in devfs_vnops.c
6. Staticize most of the spec and fifofs vnops functions.
7. Make UFS panic if it lacks bits of the underlying storage handling.
1. Remove comment stating the blatantly obvious.
2. Align in two columns.
3. Sort all but the default element alphabetically.
4. Remove XXX comments pointing out entries not needed.
Distribute all but the most fundamental malloc types. This time I also
remembered the trick to making things static: Put "static" in front of
them.
A couple of finer points by: bde
1. Clustered I/O is switched by the MNT_NOCLUSTERR and MNT_NOCLUSTERW
bits of the mnt_flag. The sysctl variables, vfs.foo.doclusterread
and vfs.foo.doclusterwrite are deleted. Only mount option can
control clustered I/O from userland.
2. When foofs_mount mounts block device, foofs_mount checks D_CLUSTERR
and D_CLUSTERW bits of the d_flags member in the block device switch
table. If D_NOCLUSTERR / D_NOCLUSTERW are set, MNT_NOCLUSTERR /
MNT_NOCLUSTERW bits will be set. In this case, MNT_NOCLUSTERR and
MNT_NOCLUSTERW cannot be cleared from userland.
3. Vnode driver disables both clustered read and write.
4. Union filesystem disables clutered write.
Reviewed by: bde
plus the previous changes to use the zone allocator decrease the useage
of malloc by half. The Zone allocator will be upgradeable to be able
to use per CPU-pools, and has more intelligent usage of SPLs. Additionally,
it has reasonable stats gathering capabilities, while making most calls
inline.
This unifies several times in theory indentical 50 lines of code.
The filesystems have a new method: vop_cachedlookup, which is the
meat of the lookup, and use vfs_cache_lookup() for their vop_lookup
method. vfs_cache_lookup() will check the namecache and pass on
to the vop_cachedlookup method in case of a miss.
It's still the task of the individual filesystems to populate the
namecache with cache_enter().
Filesystems that do not use the namecache will just provide the
vop_lookup method as usual.
free list problem. Also, the vnode age flag is no longer used by the
vnode pager. (It is actually incorrect to use then.) Constructive
feedback welcome -- just be kind.
socket addresses in mbufs. (Socket buffers are the one exception.) A number
of kernel APIs needed to get fixed in order to make this happen. Also,
fix three protocol families which kept PCBs in mbufs to not malloc them
instead. Delete some old compatibility cruft while we're at it, and add
some new routines in the in_cksum family.
uerror == 0 && lerror == EACCES, lowervp == NULLVP and union_allocvp
doesn't find existing union node and new union node is created.
Sicne it is dificult to cover all the case, union_lookup always
returns when union_lookup1() returns EACCES.
Submitted by: Naofumi Honda <honda@Kururu.math.sci.hokudai.ac.jp>
Obtained from: NetBSD/pc98
reading/writing of mem and regs). Also have to check for the requesting
process being group KMEM -- this is a bit of a hack, but ps et al need it.
Reviewed by: davidg
. It makes cd9660 root f/s working again.
. It makes CD9660 a new-style option.
. It adds support to mount an ISO9660 multi-session CD-ROM as the root
filesystem (the last session actually, but that's what is expected
behaviour).
Sigh. The CDIOREADTOCENTRYS did a copyout() of its own, and thus has
been unusable for me for this work. Too bad it didn't simply stuff
the max 100 entries into the struct ioc_read_toc_entry, but relied on
a user supplied data buffer instead. :-( I now had to reinvent the
wheel, and created a CDIOREADTOCENTRY ioctl command that can be used
in a kernel context.
While doing this, i noticed the following bogosities in existing CD-ROM
drivers:
wcd: This driver is likely to be totally bogus when someone tries
two succeeding CDIOREADTOCENTRYS (or now CDIOREADTOCENTRY)
commands with requesting MSF format, since it apparently
operates on an internal table.
scd: This driver apparently returns just a single TOC entry only for
the CDIOREADTOCENTRYS command.
I have only been able to test the CDIOREADTOCENTRY command with the
cd(4) driver. I hereby request the respective maintainers of the
other CD-ROM drivers to verify my code for their driver. When it
comes to merging this CD-ROM multisession stuff into RELENG_2_2 i will
only consider drivers where i've got a confirmation that it actually
works.
in savedvp variable and it is used for the argument of
MOUNTTOUNIONMOUNT(). I didn't realize ap->a_vp is modified before
MOUNTTOUNIONMOUNT(), so the change by revision 1.22 is incorrect.
but searching the directory on something else than the default
location.
NB: this comprises an interface change to the mount_cd9660(8)
utility (commit will follow). You need to rebuild both.
I've got similar patches for RELENG_2_2, should i commit them too?
UN_KLOCK flag.
When UN_KLOCK is set, VOP_UNLOCK should keep uppervp locked and clear
UN_ULOCK flag. To do this, when UN_KLOCK is set, (1) union_unlock
clears UN_ULOCK and does not clear UN_KLOCK, (2) union_lock() does not
access uppervp and does not clear UN_KLOCK, and (3) callers of
vput/VOP_UNLOCK should clear UN_KLOCK. For example, vput becomes:
SETKLOCK(union_node);
vput(vnode);
CLEARKLOCK(union_node);
where SETKLOCK macro sets UN_KLOCK and CLEARKLOCK macro clears
UN_KLOCK.
Our vput calls vm_object_deallocate() --> vm_object_terminate(). The
vm_object_terminate() calls vn_lock(), since UN_LOCKED has been
already cleared in union_unlock(). Then, union_lock locks upper vnode
when UN_ULOCK is not set. The upper vnode is not unlocked when
UN_KLOCK is set in union_unlock(), thus, union_lock tries to lock
locked vnode and we get panic.
UN_ULOCK flag. This shows a locking violation but I couldn't find the
reason UN_ULOCK is not set or upper vnode is not unlocked. I added
the code that detect this case and adjust un_flags. DIAGNOSTIC kernel
doesn't adjust un_flags, but just panic here to help debug by kernel
hackers.
# mount -t union (or null) dir1 dir2
# mount -t union (or null) dir2 dir1
The function namei in union_mount calls union_root. The upper vnode
has been already locked and vn_lock in union_root causes above panic.
Add printf's included in `#ifdef DIAGNOSTIC' for EDEADLK cases.
is NULLVP, union node will have neither uppervp nor lowervp. This
causes page fault trap.
The union_removed_upper just remove union node from cache and it
doesn't set uppervp to NULLVP. Since union node is removed from
cache, it will not be referenced.
The code that remove union node from cache was copied from
union_inactive.
VOP_LINK(). The reason of strange behavior was wrong order of the
argument, that is, the operation
# ln foo bar
in a union fs tried to do
# ln bar foo
in ufs layer.
Now we can make a link in a union fs.
fix!
The ufs_link() assumes that vnode is not unlocked and tries to lock it
in certain case. Because union_link calls VOP_LINK after locking vnode,
vn_lock in ufs_link causes above panic.
Currently, I don't know the real fix for a locking violation in
union_link, but I think it is important to avoid panic.
A vnode is unlocked before calling VOP_LINK and is locked after it if
the vnode is not union fs. Even though panic went away, the process
that access the union fs in which link was made will hang-up.
Hang-up can be easily reproduced by following operation:
mount -t union a b
cd b
ln foo bar
ls
same directory pair.
If we do:
mount -t union a b
mount -t union a b
then, (1) namei tries to lock fs which has been already locked by
first union mount and (2) union_root() tries to lock locked fs. To
avoid first deadlock condition, unlock vnode if lowerrootvp is union
node, and to avoid second case, union_mount returns EDEADLK when multi
union mount is detected.
dolock is not set (that is, targetvp == overlaying vnode object).
Current code use FIXUP macro to do this, and never unlocks overlaying
vnode object in union_fsync. So, the vnode object will be locked
twice and never unlocked.
PR: 3271
Submitted by: kato
relookup() in union_relookup() is succeeded. However, if relookup()
returns non-zero value, that is relookup fails, VOP_MKDIR is never
called (c.f. union_mkshadow). Thus, pathname buffer is never FREEed.
Reviewed by: phk
Submitted by: kato
PR: 3262
by Alan Cox <alc@cs.rice.edu>, and his description of the problem.
The bug was primarily in procfs_mem, but the mistake likely happened
due to the lack of vm system support for the operation. I added
better support for selective marking of page dirty flags so that
vm_map_pageable(wiring) will not cause this problem again.
The code in procfs_mem is now less bogus (but maybe still a little
so.)
of setting it (compiled into vfs_conf.c), but we have a dynamic system
in place. This could probably be better done via a runtime configure
flag in the VFS_SET() VFS declaration, perhaps VFCF_LOCAL, and have the
VFS code propagate this down into MNT_LOCAL at mount time. The other FS's
would need to be updated, havinf UFS and MSDOSFS filesystems without
MNT_LOCAL breaks a few things.. the man page rebuild scans for local
filesystems and currently fails, I suspect that other tools like find
and tar with their "local filesystem only" modes might be affected.
in procfs_allocvp(). This fixes at least stat() of /proc/*/mem.
stat() of /proc/*/file already worked. I think procfs_allocvp() isn't
actually called for type Pfile.
partly because the #define's for them were moved to a different
file. At least the null VOP_LOCK() no longer works, since vclean()
expects VOP_LOCK( ..., LK_DRAIN | LK_INTERLOCK, ...) to clear the
interlock. This probably only matters when simple_lock() is not
null, i.e., when there are multiple CPUs or SIMPLELOCK_DEBUG is
defined.
- *fs_init routines now take a "struct vfsconf * vfsp" pointer
as an argument.
- Use the correct type for cookies.
- Update function prototypes.
Submitted by: bde
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.
The system boots and can mount UFS filesystems.
Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
Mount_std mounts will not work until the getfsent
library routine is changed.
Reviewed by: various people
Submitted by: Jeffery Hsu <hsu@freebsd.org>
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
Firstly, now our read-ahead clustering is on a file descriptor basis and not
on a per-vnode basis. This will allow multiple processes reading the
same file to take advantage of read-ahead clustering. Secondly, there
previously was a problem with large reads still using the ramp-up
algorithm. Of course, that was bogus, and now we read the entire
"chunk" off of the disk in one operation. The read-ahead clustering
algorithm should use less CPU than the previous also (I hope :-)).
NOTE: THAT LKMS MUST BE REBUILT!!!
successful write. Only do it for the IO_SYNC case (like ufs). On
one of my systems, this speeds up `iozone 24 512' from 32K/sec
(1/128 as fast as ufs) to 2.8MB/sec (7/10 as fast as ufs).
Obtained from: partly from NetBSD
Broke locking on named pipes in the same way as locking on non-vnodes
(wrong errno). This will be fixed later.
The fix involves negative logic. Named pipes are now distinguished from
other types of files with vnodes, and there is additional code to handle
vnodes and named pipes in the same way only where that makes sense (not
for lseek, locking or TIOCSCTTY).
fcntl() and EOPNOTSUPP for flock(). POSIX specifies the weaker EINVAL
errno and the man page agrees.
Not fixed:
deadfs: always returns wrong EBADF
devfs, msdosfs: always return sometimes-wrong EINVAL
cd9660, fdesc, kernfs, portal: always return sometimes-wrong EOPNOTSUPP
procfs: always returns wrong EIO
mfs: panic?!
nfs: fudged
NetBSD uses a generic file system genfs to do return the sometimes-wrong
EOPNOTSUPP more consistently :-)(.
Found by: NIST-PCTS
certain error conditions, it is possible for pages to be left allocated
in the object beyond it's end. It is generally bad practice to allocate
pages beyond the end of an object.
/*
* Structure defined by POSIX.4 to be like a timeval.
*/
struct timespec {
time_t ts_sec; /* seconds */
long ts_nsec; /* and nanoseconds */
};
The correct names of the fields are tv_sec and tv_nsec.
Reminded by: James Drobina <jdrobina@infinet.com>
The interface into the "VMIO" system has changed to be more consistant
and robust. Essentially, it is now no longer necessary to call vn_open
to get merged VM/Buffer cache operation, and exceptional conditions
such as merged operation of VBLK devices is simpler and more correct.
This code corrects a potentially large set of problems including the
problems with ktrace output and loaded systems, file create/deletes,
etc.
Most of the changes to NFS are cosmetic and name changes, eliminating
a layer of subroutine calls. The direct calls to vput/vrele have
been re-instituted for better cross platform compatibility.
Reviewed by: davidg
to information from a single process causes hangs. Specifically, this
fixes problems (hangs) with concurrent ps commands, when the system is under
heavy memory load.
Reviewed by: davidg
but not there. The extent of the object lock is expanded to be over the
range that it is needed. Additionally, clean up the code so that it conforms
to better coding style.
with multiple entries as follows:
start address, end address, resident pages in range, private pages
in range, RW/RO, COW or not, (vnode/device/swap/default).
All new code is "#ifdef PC98"ed so this should make no difference to
PC/AT (and its clones) users.
Ok'd by: core
Submitted by: FreeBSD(98) development team
process won't possibly block before filling in the fsnode pointer (v_data)
which might be dereferenced during a sync since the vnode is put on the
mnt_vnodelist by getnewvnode.
Pointed out by Matt Day <mday@artisoft.com>
process won't possibly block before filling in the fsnode pointer (v_data)
which might be dereferenced during a sync since the vnode is put on the
mnt_vnodelist by getnewvnode.
device have reference count problems. We mark the underlying object
ono-persistent, and account for the reference count that the VM system
maintainsfor the special device close. This should fix the removable
device problem.
files are off the vendor branch, so this should not change anything.
A "U" marker generally means that the file was not changed in between
the 4.4Lite and Lite-2 releases, and does not need a merge. "C" generally
means that there was a change.
[note, new file: cd9660_mount.h]
This is a really ugly bandaid on the problem, but it works well enough for
'ps -u' to start working again. The problem was caused by the user
address space shrinking by a little bit and the UPAGES being "cast off" to
become a seperate entity rather than being at the top of the process's
vmspace. That optimization was part of John's most recent VM speedups.
Now, rather than decoding the VM space, it merely ensures the pages are
in core and accesses them the same way the ptrace(PT_READ_U..) code does,
ie: off the p->p_addr pointer.
Implement a "variable" directory structure. Files that do not make
sense for the given process do not "appear" and cannot be opened.
For example, "system" processes do not have "file", "regs" or "fpregs",
because they do not have a user area.
"attempt" to fill in the user area of a given process when it is being
accessed via /proc/pid/mem (the user struct is just after
VM_MAXUSER_ADDRESS in the process address space.)
Dont do IO to the U area while it's swapped, hold it in place if possible.
Lock off access to the "ctl" file if it's done a setuid like the other
pseudo-files in there.
Speed up for vfs_bio -- addition of a routine bqrelse to greatly diminish
overhead for merged cache.
Efficiency improvement for vfs_cluster. It used to do alot of redundant
calls to cluster_rbuild.
Correct the ordering for vrele of .text and release of credentials.
Use the selective tlb update for 486/586/P6.
Numerous fixes to the size of objects allocated for files. Additionally,
fixes in the various pagers.
Fixes for proper positioning of vnode_pager_setsize in msdosfs and ext2fs.
Fixes in the swap pager for exhausted resources. The pageout code
will not as readily thrash.
Change the page queue flags (PG_ACTIVE, PG_INACTIVE, PG_FREE, PG_CACHE) into
page queue indices (PQ_ACTIVE, PQ_INACTIVE, PQ_FREE, PQ_CACHE),
thereby improving efficiency of several routines.
Eliminate even more unnecessary vm_page_protect operations.
Significantly speed up process forks.
Make vm_object_page_clean more efficient, thereby eliminating the pause
that happens every 30seconds.
Make sequential clustered writes B_ASYNC instead of B_DELWRI even in the
case of filesystems mounted async.
Fix a panic with busy pages when write clustering is done for non-VMIO
buffers.
seems to work hre just fine though I can't check every file
that changed due to limmited h/w, however I've checked enught to be petty
happy withe hte code..
WARNING... struct lkm[mumble] has changed
so it might be an idea to recompile any lkm related programs
most devsw referenced functions are now static, as they are
in the same file as their devsw structure. I've also added DEVFS
support for nearly every device in the system, however
many of the devices have 'incorrect' names under DEVFS
because I couldn't quickly work out the correct naming conventions.
(but devfs won't be coming on line for a month or so anyhow so that doesn't
matter)
If you "OWN" a device which would normally have an entry in /dev
then search for the devfs_add_devsw() entries and munge to make them right..
check out similar devices to see what I might have done in them in you
can't see what's going on..
for a laugh compare conf.c conf.h defore and after... :)
I have not doen DEVFS entries for any DISKSLICE devices yet as that will be
a much more complicated job.. (pass 5 :)
pass 4 will be to make the devsw tables of type (cdevsw * )
rather than (cdevsw)
seems to work here..
complaints to the usual places.. :)
cd9660_rrip.c:
Added lots of bogus casts to hide type errors exposed by the prototypes.
(Different structs are assumed to have a common prefix.)
cd9660_vnops.c:
Finished staticizing.
add a few safety checks in specfs because
now it's possible to get entries in [cd]devsw[] which are ALL NULL
so it's better to discover this BEFORE jumping into the d_open() entry..
more check to come later.. this getsthe code to the stage where I
can start testing it, even if I haven't caught every little error case...
I guess I'll find them quick enough..
for certain common combinations of directory sizes, cluster sizes, and i/o
sizes (e.g., 4K, 4K, and 4K). The fix in rev. 1.21 was incomplete.
Reviewed by: dfr
Obtained from: party from NetBSD
The fix for this in Lite-2 is more complete, but these quick hacks of mine
are safer for now. I plan to integrate the additional Lite-2 stuff at some
later time. Should completely fix PR810.
it 1138 times (:-() in casts and a few more times in declarations.
This change is null for the i386.
The type has to be `typedef int vop_t(void *)' and not `typedef
int vop_t()' because `gcc -Wstrict-prototypes' warns about the
latter. Since vnode op functions are called with args of different
(struct pointer) types, neither of these function types is any use
for type checking of the arg, so it would be preferable not to use
the complete function type, especially since using the complete
type requires adding 1138 casts to avoid compiler warnings and
another 40+ casts to reverse the function pointer conversions before
calling the functions.
Should anybody out there wonder about this vendetta against global
variables, it is basically to make it more visible what our interfaces
in the kernel really are.
I'm almost convinced we should have a
#define PUBLIC /* public interface */
and use it in the #includes...
filesystem layer, as was done in lite-2. Merged in some other cosmetic
changes while I was at it. Rewrote most of msdosfs_access() to be more
like ufs_access() and to include the FS read-only check.
Obtained from: partially from 4.4BSD-lite2
calls.
Found by: gcc -Wstrict-prototypes after I supplied some of the 5000+
missing prototypes. Now I have 9000+ lines of warnings and errors
about bogus conversions of function pointers.
SunOS and SCO. You can then even use the pipe as a cheap fifo stack
(yuck!). A semantic change also important (but not limited) to iBCS2
compatibility.
Submitted by: swallace
wrong vp's ops vector being used by changing the VOP_LINK's argument order.
The special-case hack doesn't go far enough and breaks the generic
bypass routine used in some non-leaf filesystems. Pointed out by Kirk
McKusick.
don't go away when the kernel is compiled with -O.
The functions are backed up by extern versions in cd9660_util.c,
but these versions are disabled by `#ifdef __notanymore__'. They
could have been enabled by using `#if defined(__notanymore__) ||
!defined(__OPTIMIZE__)' but then I would have had to check that
they still work. The correct way to handle all this is to replace
`extern inline' by `EXTERN_INLINE' and define `EXTERN_INLINE' as
`extern inline' in most modules and as empty in one module.
associated files.
Submitted by: leo@dachau.marco.de (Matthias Pfaller)
Not-obtained from: NetBSD. Instead sent directly to me by Matthias.
(Sorry, this is to prevent people from claiming i might have gotten
this from NetBSD. :)
proc or any VM system structure will have to be rebuilt!!!
Much needed overhaul of the VM system. Included in this first round of
changes:
1) Improved pager interfaces: init, alloc, dealloc, getpages, putpages,
haspage, and sync operations are supported. The haspage interface now
provides information about clusterability. All pager routines now take
struct vm_object's instead of "pagers".
2) Improved data structures. In the previous paradigm, there is constant
confusion caused by pagers being both a data structure ("allocate a
pager") and a collection of routines. The idea of a pager structure has
escentially been eliminated. Objects now have types, and this type is
used to index the appropriate pager. In most cases, items in the pager
structure were duplicated in the object data structure and thus were
unnecessary. In the few cases that remained, a un_pager structure union
was created in the object to contain these items.
3) Because of the cleanup of #1 & #2, a lot of unnecessary layering can now
be removed. For instance, vm_object_enter(), vm_object_lookup(),
vm_object_remove(), and the associated object hash list were some of the
things that were removed.
4) simple_lock's removed. Discussion with several people reveals that the
SMP locking primitives used in the VM system aren't likely the mechanism
that we'll be adopting. Even if it were, the locking that was in the code
was very inadequate and would have to be mostly re-done anyway. The
locking in a uni-processor kernel was a no-op but went a long way toward
making the code difficult to read and debug.
5) Places that attempted to kludge-up the fact that we don't have kernel
thread support have been fixed to reflect the reality that we are really
dealing with processes, not threads. The VM system didn't have complete
thread support, so the comments and mis-named routines were just wrong.
We now use tsleep and wakeup directly in the lock routines, for instance.
6) Where appropriate, the pagers have been improved, especially in the
pager_alloc routines. Most of the pager_allocs have been rewritten and
are now faster and easier to maintain.
7) The pagedaemon pageout clustering algorithm has been rewritten and
now tries harder to output an even number of pages before and after
the requested page. This is sort of the reverse of the ideal pagein
algorithm and should provide better overall performance.
8) Unnecessary (incorrect) casts to caddr_t in calls to tsleep & wakeup
have been removed. Some other unnecessary casts have also been removed.
9) Some almost useless debugging code removed.
10) Terminology of shadow objects vs. backing objects straightened out.
The fact that the vm_object data structure escentially had this
backwards really confused things. The use of "shadow" and "backing
object" throughout the code is now internally consistent and correct
in the Mach terminology.
11) Several minor bug fixes, including one in the vm daemon that caused
0 RSS objects to not get purged as intended.
12) A "default pager" has now been created which cleans up the transition
of objects to the "swap" type. The previous checks throughout the code
for swp->pg_data != NULL were really ugly. This change also provides
the rudiments for future backing of "anonymous" memory by something
other than the swap pager (via the vnode pager, for example), and it
allows the decision about which of these pagers to use to be made
dynamically (although will need some additional decision code to do
this, of course).
13) (dyson) MAP_COPY has been deprecated and the corresponding "copy
object" code has been removed. MAP_COPY was undocumented and non-
standard. It was furthermore broken in several ways which caused its
behavior to degrade to MAP_PRIVATE. Binaries that use MAP_COPY will
continue to work correctly, but via the slightly different semantics
of MAP_PRIVATE.
14) (dyson) Sharing maps have been removed. It's marginal usefulness in a
threads design can be worked around in other ways. Both #12 and #13
were done to simplify the code and improve readability and maintain-
ability. (As were most all of these changes)
TODO:
1) Rewrite most of the vnode pager to use VOP_GETPAGES/PUTPAGES. Doing
this will reduce the vnode pager to a mere fraction of its current size.
2) Rewrite vm_fault and the swap/vnode pagers to use the clustering
information provided by the new haspage pager interface. This will
substantially reduce the overhead by eliminating a large number of
VOP_BMAP() calls. The VOP_BMAP() filesystem interface should be
improved to provide both a "behind" and "ahead" indication of
contiguousness.
3) Implement the extended features of pager_haspage in swap_pager_haspage().
It currently just says 0 pages ahead/behind.
4) Re-implement the swap device (swstrategy) in a more elegant way, perhaps
via a much more general mechanism that could also be used for disk
striping of regular filesystems.
5) Do something to improve the architecture of vm_object_collapse(). The
fact that it makes calls into the swap pager and knows too much about
how the swap pager operates really bothers me. It also doesn't allow
for collapsing of non-swap pager objects ("unnamed" objects backed by
other pagers).
regular user could panic the machine with a simple "tail /proc/curproc/mem"
command. The problem was twofold: both kernfs and procfs didn't fill in
the mnt_stat statfs struct (which would later lead to an integer divide
fault in the vnode pager), and kernfs bogusly paniced if a bmap was
attempted.
Reviewed by: John Dyson
These changes solve the problem in a general way by moving the
initialization out of the individual fs_mountroot's and into swaponvp().
Submitted by: Poul-Henning Kamp
msdosfs_lookup() did no validation to see if the caller was validated
to delete/rename/create files. msdosfs_setattr() did no validation
to see if the caller was allowed to change the file permissions (turn
on/off the write bit) or update the file modification time (utimes).
The routines were fixed to validate the calls just like ufs does.
Fix PR 303: msdosfs: moving a file into another directory causes panic.
" ... the code that does the rename already has the denode
locked when msdosfs_hashins() gets called, resulting in the panic
when the routine attempts to lock the denode again.
...
The attached patch changes the msdosfs_hashins() routine to not lock the
denode. The caller is now resposible for obtaining the lock instead
of having msdosfs_hashins() do it for them."
Fixed remaining known bugs in the buffer IO and VM system.
vfs_bio.c:
Fixed some race conditions and locking bugs. Improved performance
by removing some (now) unnecessary code and fixing some broken
logic.
Fixed process accounting of # of FS outputs.
Properly handle NFS interrupts (B_EINTR).
(various)
Replaced calls to clrbuf() with calls to an optimized routine
called vfs_bio_clrbuf().
(various FS sync)
Sync out modified vnode_pager backed pages.
ffs_vnops.c:
Do two passes: Sync out file data first, then indirect blocks.
vm_fault.c:
Fixed deadly embrace caused by acquiring locks in the wrong order.
vnode_pager.c:
Changed to use buffer I/O system for writing out modified pages. This
should fix the problem with the modification date previous not getting
updated. Also dramatically simplifies the code. Note that this is
going to change in the future and be implemented via VOP_PUTPAGES().
vm_object.c:
Fixed a pile of bugs related to cleaning (vnode) objects. The performance
of vm_object_page_clean() is terrible when dealing with huge objects,
but this will change when we implement a binary tree to keep the object
pages sorted.
vm_pageout.c:
Fixed broken clustering of pageouts. Fixed race conditions and other
lockup style bugs in the scanning of pages. Improved performance.
