Commit Graph

29 Commits

Author SHA1 Message Date
bde
3029c788af Ignore trailing slashes in pathnames that "refer to a directory",
as is required to be POSIXLY_CORRECT and "right".  I interpret
"referring to a directory" as being a directory or becoming a
directory.  E.g., the trailing slashes in mkdir("/nonesuch/"),
rename("/tmp", /nonesuch/") and link("/tmp", "/root_can_like_dirs/")
are ignored because the target will become a directory if the
syscall succeeds.  A trailing slash on a symlink causes the symlink
to be followed (this is a bug if the symlink doesn't point to a
directory; fix later).
1995-07-31 00:35:58 +00:00
dg
c8b0a7332c NOTE: libkvm, w, ps, 'top', and any other utility which depends on struct
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).
1995-07-13 08:48:48 +00:00
dg
3c7c1dd62f 1) Converted v_vmdata to v_object.
2) Removed unnecessary vm_object_lookup()/pager_cache(object, TRUE) pairs
   after vnode_pager_alloc() calls - the object is already guaranteed to be
   persistent.
3) Removed some gratuitous casts.
1995-06-28 12:01:13 +00:00
dg
5d0d9f974b Fixed VOP_LINK argument order botch. 1995-06-28 07:06:55 +00:00
dg
2045200a00 Changes to fix the following bugs:
1) Files weren't properly synced on filesystems other than UFS. In some
   cases, this lead to lost data. Most likely would be noticed on NFS.
   The fix is to make the VM page sync/object_clean general rather than
   in each filesystem.
2) Mixing regular and mmaped file I/O on NFS was very broken. It caused
   chunks of files to end up as zeroes rather than the intended contents.
   The fix was to fix several race conditions and to kludge up the
   "b_dirtyoff" and "b_dirtyend" that NFS relies upon - paying attention
   to page modifications that occurred via the mmapping.

Reviewed by:	David Greenman
Submitted by:	John Dyson
1995-05-21 21:39:31 +00:00
dg
138edd5273 Fixed incompleteness that would allow dirty filesystems to get mounted
when the single user shell was terminated. These changes disallow mounting
or R/W upgrading filesystems that are dirty unless "-f" (force) option
is used with mount. /etc/rc has been modified to abort the startup if
one or more non-nfs partitions fail to mount.

Reviewed by:	Poul-Henning Kamp, Rod Grimes
1995-05-15 08:39:37 +00:00
dg
bdaf4b444d Removed unused variable caused by last commit. 1995-05-02 09:06:04 +00:00
dg
381c266547 Fix for sync() to close a potential panic with accessing a mount struct
that had been freed.

Submitted by:	John Dyson
1995-05-02 08:44:31 +00:00
dg
8b14c6a8ea Added a set of braces to make the compiler happy. 1995-03-29 11:54:02 +00:00
dg
a62ef20881 Moved call to vnode_pager_uncache in rename() to before the VOP_RENAME.
It was previously after the VOP_RENAME and the reference and lock on
the vnode had already been lost, allowing interesting internel
inconsistencies. This is one of the two reasons why freefall was crashing
every hour or two (the other being nullfs bugs).
Don't call vnode_pager_uncache in revoke(). revoke() is only allowed on
VCHR and VBLK vnodes.
1995-03-19 11:16:58 +00:00
bde
289f11acb4 Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) and most of the warnings from
`gcc -Wnested-externs'.  Fix all the bugs found.  There were no serious
ones.
1995-03-16 18:17:34 +00:00
dg
191e07d353 Do a vnode_pager_uncache after the VOP_RENAME to lose the remaining
reference to the old vnode.

Suggested by:	Bruce Evans
1995-02-28 02:52:48 +00:00
dg
a0467b5c60 In sync(), don't dereference the proc pointer if it's NULL. Should fix
most or all of the problems with calling sync() without a curproc (which
can happen in machdep.c during a panic sync).
1995-02-13 13:45:04 +00:00
dg
e5d78dd23f From tim@cs.city.ac.uk (Tim Wilkinson):
Find enclosed a short bugfix to get the union filesystem up and running
in FreeBSD-current.  We don't think we've got all the problems yet but
these fixes sort out the major ones (which mostly concert bad locking
of vnodes), no doubt we'll post others as necessary.  Known problems
include the inability of the umount command (not the system call) to unmount
unions in certain circumstances (this is due the way "realpath" works),
and the failure of direntries to always get all available files in
unioned subdirectories.  We are, as they say, working on it.

Submitted by:	tim@cs.city.ac.uk (Tim Wilkinson)
1994-11-04 14:41:46 +00:00
wollman
3a9b1c345a Make my ALLDEVS kernel compile (basically, LINT minus a lot of options).
This involves fixing a few things I broke last time.
1994-10-21 01:19:28 +00:00
phk
c4b061eaa0 Fix the problem with panics when mounting on nonexistant directories. Probably
my fault in the first place...
1994-10-15 02:53:26 +00:00
sos
45e2713230 Removed static declaration of getvnode() (used in ibcs2) 1994-10-11 20:40:12 +00:00
phk
5f8e9e2c4d Cosmetics: added ()'s and fixed prinf-formats to make gcc silent. 1994-10-08 22:33:43 +00:00
dg
52b4dc9c30 Stuff object into v_vmdata rather than pager. Not important which at
the moment, but will be in the future. Other changes mostly cosmetic,
but are made for future VMIO considerations.

Submitted by:	John Dyson
1994-10-05 09:48:45 +00:00
phk
c3e4945541 All of this is cosmetic. prototypes, #includes, printfs and so on. Makes
GCC a lot more silent.
1994-10-02 17:35:40 +00:00
dfr
57b6c0c34c Make NFS ask the filesystems for directory cookies instead of making them
itself.
1994-09-28 16:45:22 +00:00
wollman
900d29807d More loadable VFS changes:
- Make a number of filesystems work again when they are statically compiled
  (blush)

- FIFOs are no longer optional; ``options FIFO'' removed from distributed
  config files.
1994-09-22 19:38:41 +00:00
wollman
c289ac89a1 Implemented loadable VFS modules, and made most existing filesystems
loadable.  (NFS is a notable exception.)
1994-09-21 03:47:43 +00:00
dg
70a7b53e06 Disallow truncating to negative file sizes. Doing so causes ffs_truncate()
and perhaps other fs truncate's to go crazy and panic the machine or worse.
This fixes the truncate bug reported by Michael Class.
1994-09-02 10:23:43 +00:00
dg
4e8717c691 Make olstat() consistent with lstat() - so they both return the same
owner..

Submitted by:	Kirk McKusick
1994-09-02 04:14:44 +00:00
dg
f817326b2e Implemented filesystem clean bit via:
machdep.c:
	Changed printf's a little and call vfs_unmountall() if the sync was
	successful.

cd9660_vfsops.c, ffs_vfsops.c, nfs_vfsops.c, lfs_vfsops.c:
	Allow dismount of root FS. It is now disallowed at a higher level.

vfs_conf.c:
	Removed unused rootfs global.

vfs_subr.c:
	Added new routines vfs_unmountall and vfs_unmountroot. Filesystems
	are now dismounted if the machine is properly rebooted.

ffs_vfsops.c:
	Toggle clean bit at the appropriate places. Print warning if an
	unclean FS is mounted.

ffs_vfsops.c, lfs_vfsops.c:
	Fix bug in selecting proper flags for VOP_CLOSE().

vfs_syscalls.c:
	Disallow dismounting root FS via umount syscall.
1994-08-20 16:03:26 +00:00
dg
8d205697aa Added $Id$ 1994-08-02 07:55:43 +00:00
rgrimes
2469c867a1 The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.
Reviewed by:	Rodney W. Grimes
Submitted by:	John Dyson and David Greenman
1994-05-25 09:21:21 +00:00
rgrimes
8fb65ce818 BSD 4.4 Lite Kernel Sources 1994-05-24 10:09:53 +00:00