Commit Graph

1614 Commits

Author SHA1 Message Date
brooks
f53c1c309d Rework the credential code to support larger values of NGROUPS and
NGROUPS_MAX, eliminate ABI dependencies on them, and raise the to 1024
and 1023 respectively.  (Previously they were equal, but under a close
reading of POSIX, NGROUPS_MAX was defined to be too large by 1 since it
is the number of supplemental groups, not total number of groups.)

The bulk of the change consists of converting the struct ucred member
cr_groups from a static array to a pointer.  Do the equivalent in
kinfo_proc.

Introduce new interfaces crcopysafe() and crsetgroups() for duplicating
a process credential before modifying it and for setting group lists
respectively.  Both interfaces take care for the details of allocating
groups array. crsetgroups() takes care of truncating the group list
to the current maximum (NGROUPS) if necessary.  In the future,
crsetgroups() may be responsible for insuring invariants such as sorting
the supplemental groups to allow groupmember() to be implemented as a
binary search.

Because we can not change struct xucred without breaking application
ABIs, we leave it alone and introduce a new XU_NGROUPS value which is
always 16 and is to be used or NGRPS as appropriate for things such as
NFS which need to use no more than 16 groups.  When feasible, truncate
the group list rather than generating an error.

Minor changes:
  - Reduce the number of hand rolled versions of groupmember().
  - Do not assign to both cr_gid and cr_groups[0].
  - Modify ipfw to cache ucreds instead of part of their contents since
    they are immutable once referenced by more than one entity.

Submitted by:	Isilon Systems (initial implementation)
X-MFC after:	never
PR:		bin/113398 kern/133867
2009-06-19 17:10:35 +00:00
snb
af1efe0490 Keep dirhash tailq locked throughout the entirety of ufsdirhash_destroy() to fix
a potential race pointed out by pjd. Also use TAILQ_FOREACH_SAFE to iterate over
dirhashes in ufsdirhash_lowmem(), so that we can continue iterating even after a
dirhash is destroyed.

Suggested by:	pjd
Tested by:      pho
Approved by:	dwmalone (mentor)
2009-06-17 18:55:29 +00:00
kib
b8351fcda2 Do not use casts (int *)0 and (struct thread *)0 for the arguments of
vn_rdwr, use NULL.

Reviewed by:	jhb
MFC after:	1 week
2009-06-16 15:13:45 +00:00
rwatson
f4934662e5 Move "options MAC" from opt_mac.h to opt_global.h, as it's now in GENERIC
and used in a large number of files, but also because an increasing number
of incorrect uses of MAC calls were sneaking in due to copy-and-paste of
MAC-aware code without the associated opt_mac.h include.

Discussed with:	pjd
2009-06-05 14:55:22 +00:00
snb
7f32f3f2a1 Add vm_lowmem event handler for dirhash. This will cause dirhashes to be
deleted when the system is low on memory. This ought to allow an increase to
vfs.ufs.dirhash_maxmem on machines that have lots of memory, without
degrading performance by having too much memory reserved for dirhash when
other things need it. The default value for dirhash_maxmem is being kept at
2MB for now, though.

This work was mostly done during the 2008 Google Summer of Code.

Approved by:	dwmalone (mentor), re
MFC after:	3 months
2009-06-03 09:44:22 +00:00
attilio
44c490ae17 Handle lock recursion differenty by always checking against LO_RECURSABLE
instead the lock own flag itself.

Tested by:	pho
2009-06-02 13:03:35 +00:00
jamie
a013e0afcb Add hierarchical jails. A jail may further virtualize its environment
by creating a child jail, which is visible to that jail and to any
parent jails.  Child jails may be restricted more than their parents,
but never less.  Jail names reflect this hierarchy, being MIB-style
dot-separated strings.

Every thread now points to a jail, the default being prison0, which
contains information about the physical system.  Prison0's root
directory is the same as rootvnode; its hostname is the same as the
global hostname, and its securelevel replaces the global securelevel.
Note that the variable "securelevel" has actually gone away, which
should not cause any problems for code that properly uses
securelevel_gt() and securelevel_ge().

Some jail-related permissions that were kept in global variables and
set via sysctls are now per-jail settings.  The sysctls still exist for
backward compatibility, used only by the now-deprecated jail(2) system
call.

Approved by:	bz (mentor)
2009-05-27 14:11:23 +00:00
trasz
fb57d2691e Make 'struct acl' larger, as required to support NFSv4 ACLs. Provide
compatibility interfaces in both kernel and libc.

Reviewed by:	rwatson
2009-05-22 15:56:43 +00:00
alc
dc942dabcf Introduce vfs_bio_set_valid() and use it from ffs_realloccg(). This
eliminates the misuse of vfs_bio_clrbuf() by ffs_realloccg().

In collaboration with:	tegge
2009-05-17 20:26:00 +00:00
attilio
1dcb84131b Remove the thread argument from the FSD (File-System Dependent) parts of
the VFS.  Now all the VFS_* functions and relating parts don't want the
context as long as it always refers to curthread.

In some points, in particular when dealing with VOPs and functions living
in the same namespace (eg. vflush) which still need to be converted,
pass curthread explicitly in order to retain the old behaviour.
Such loose ends will be fixed ASAP.

While here fix a bug: now, UFS_EXTATTR can be compiled alone without the
UFS_EXTATTR_AUTOSTART option.

VFS KPI is heavilly changed by this commit so thirdy parts modules needs
to be recompiled.  Bump __FreeBSD_version in order to signal such
situation.
2009-05-11 15:33:26 +00:00
kan
7b57a857b7 Do not embed struct ucred into larger netcred parent structures.
Credential might need to hang around longer than its parent and be used
outside of mnt_explock scope controlling netcred lifetime. Use separate
reference-counted ucred allocated separately instead.

While there, extend mnt_explock coverage in vfs_stdexpcheck and clean-up
some unused declarations in new NFS code.

Reported by:	John Hickey
PR:		kern/133439
Reviewed by:	dfr, kib
2009-05-09 18:09:17 +00:00
rmacklem
84d9dc09c0 Change the semantics of i_modrev/va_filerev to what is required for
the nfsv4 Change attribute. There are 2 changes:
 	1 - The value now changes on metadata changes as well as data
 	    modifications (incremented for IN_CHANGE instead of IN_UPDATE).
 	2 - It is now saved in spare space in the on-disk i-node so that it
 	    survives a crash.
 	Since va_filerev is not passed out into user space, the only current
 	use of va_filerev is in the nfs server, which uses it as the directory
 	cookie verifier. Since this verifier is only passed back to the server
 	by a client verbatim and then the server doesn't check it, changing the
 	semantics should not break anything currently in FreeBSD.

Reviewed by:	bde
Approved by:	kib (mentor)
2009-04-27 16:46:16 +00:00
kib
24114749aa In ufs_checkpath(), recheck that '..' still points to the inode with
the same inode number after VFS_VGET() and relock of the vp. If '..'
changed, redo the lookup. To reduce code duplication, move the code to
read '..' dirent into the static helper function ufs_dir_dd_ino().

Supply the source inode number as an argument to ufs_checkpath() instead
of the source inode itself. The inode is unlocked, thus it might be
reclaimed, causing accesses to the freed memory.

Use vn_vget_ino() to get the '..' vnode by its inode number, instead of
directly code VFS_VGET() and relock, to properly busy the mount point
while vp lock is dropped.

Noted and reviewed by:	tegge
Tested by:	pho
MFC after:	1 month
2009-04-20 14:36:01 +00:00
kib
7ee6b427ae When verifying '..' after VFS_VGET() in ufs_lookup(), do not return
error if '..' is still there but changed between lookup and check.
Start relookup instead. Rename is supposed to change '..' reference
atomically, so transient failures introduced by r191137 are wrong.

While rearranging the code to allow lookup restart in ufs_lookup(),
remove the comment that only distracts the reader.

Noted and reviewed by:	tegge
Also reported by:	pho
MFC after:	1 month
2009-04-19 05:34:07 +00:00
trasz
858b10f6e2 Use acl_alloc() and acl_free() instead of using uma(9) directly.
This will make switching to malloc(9) easier; also, it would be
neccessary to add these routines if/when we implement variable-size
ACLs.
2009-04-18 16:47:33 +00:00
kib
915dee68f2 Verify that '..' still exists with the same inode number after
VFS_VGET() has returned in ufs_lookup(). If the '..' lookup started
immediately before the parent directory was removed, we might return
either cleared or unrelated inode otherwise.

Ufs_lookup() is split into new function ufs_lookup_() that either does
lookup, or verifies that directory entry exists and references supplied
inode number.

Reviewed by:	tegge
Tested by:	pho,
	Andreas Tobler <andreast-list fgznet ch> (previous version)
MFC after:	1 month
2009-04-16 09:57:08 +00:00
rwatson
fba90f2e03 Remove VOP_LEASE and supporting functions. This hasn't been used since
the removal of NQNFS, but was left in in case it was required for NFSv4.
Since our new NFSv4 client and server can't use it for their
requirements, GC the old mechanism, as well as other unused lease-
related code and interfaces.

Due to its impact on kernel programming and binary interfaces, this
change should not be MFC'd.

Proposed by:    jeff
Reviewed by:    jeff
Discussed with: rmacklem, zach loafman @ isilon
2009-04-10 10:52:19 +00:00
kib
ec888841ec When removing or renaming snaphost, do not delve into request_cleanup().
The later may need blocks from the underlying device that belongs
to normal files, that should not be locked while snap lock is held.

Reported and tested by:	pho
MFC after:	1 month
2009-04-04 12:19:52 +00:00
kib
642970135f Correct typo.
Noted by:	kensmith
2009-03-27 15:46:02 +00:00
kib
7ad4235008 Fix two issues with bufdaemon, often causing the processes to hang in
the "nbufkv" sleep.

First, ffs background cg group block write requests a new buffer for
the shadow copy. When ffs_bufwrite() is called from the bufdaemon due
to buffers shortage, requesting the buffer deadlock bufdaemon.
Introduce a new flag for getnewbuf(), GB_NOWAIT_BD, to request getblk
to not block while allocating the buffer, and return failure
instead. Add a flag argument to the geteblk to allow to pass the flags
to getblk(). Do not repeat the getnewbuf() call from geteblk if buffer
allocation failed and either GB_NOWAIT_BD is specified, or geteblk()
is called from bufdaemon (or its helper, see below). In
ffs_bufwrite(), fall back to synchronous cg block write if shadow
block allocation failed.

Since r107847, buffer write assumes that vnode owning the buffer is
locked. The second problem is that buffer cache may accumulate many
buffers belonging to limited number of vnodes. With such workload,
quite often threads that own the mentioned vnodes locks are trying to
read another block from the vnodes, and, due to buffer cache
exhaustion, are asking bufdaemon for help. Bufdaemon is unable to make
any substantial progress because the vnodes are locked.

Allow the threads owning vnode locks to help the bufdaemon by doing
the flush pass over the buffer cache before getnewbuf() is going to
uninterruptible sleep. Move the flushing code from buf_daemon() to new
helper function buf_do_flush(), that is called from getnewbuf().  The
number of buffers flushed by single call to buf_do_flush() from
getnewbuf() is limited by new sysctl vfs.flushbufqtarget.  Prevent
recursive calls to buf_do_flush() by marking the bufdaemon and threads
that temporarily help bufdaemon by TDP_BUFNEED flag.

In collaboration with:	pho
Reviewed by:	 tegge (previous version)
Tested by:	 glebius, yandex ...
MFC after:	 3 weeks
2009-03-16 15:39:46 +00:00
kib
9e27cf574d The non-modifying EA VOPs are executed with only shared vnode lock taken.
Provide a custom lock around initializing and tearing down EA area,
to prevent both memory leaks and double-free of it. Count the number
of EA area accessors.

Lock protocol requires either holding exclusive vnode lock to modify
i_ea_area, or shared vnode lock and owning IN_EA_LOCKED flag in i_flag.

Noted by:	YAMAMOTO, Taku <taku tackymt homeip net>
Tested by:	pho (previous version)
MFC after:	2 weeks
2009-03-12 12:43:56 +00:00
kib
de74558fd8 Do not double-free the struct inode when insmntque failed. Default
insmntque destructor reclaims the vnode, and ufs_reclaim frees the memory.

Reviewed by:	tegge
MFC after:	3 days
2009-03-11 19:45:52 +00:00
jhb
520acdaf69 Add a new internal mount flag (MNTK_EXTENDED_SHARED) to indicate that a
filesystem supports additional operations using shared vnode locks.
Currently this is used to enable shared locks for open() and close() of
read-only file descriptors.
- When an ISOPEN namei() request is performed with LOCKSHARED, use a
  shared vnode lock for the leaf vnode only if the mount point has the
  extended shared flag set.
- Set LOCKSHARED in vn_open_cred() for requests that specify O_RDONLY but
  not O_CREAT.
- Use a shared vnode lock around VOP_CLOSE() if the file was opened with
  O_RDONLY and the mountpoint has the extended shared flag set.
- Adjust md(4) to upgrade the vnode lock on the vnode it gets back from
  vn_open() since it now may only have a shared vnode lock.
- Don't enable shared vnode locks on FIFO vnodes in ZFS and UFS since
  FIFO's require exclusive vnode locks for their open() and close()
  routines.  (My recent MPSAFE patches for UDF and cd9660 already included
  this change.)
- Enable extended shared operations on UFS, cd9660, and UDF.

Submitted by:	ups
Reviewed by:	pjd (ZFS bits)
MFC after:	1 month
2009-03-11 14:13:47 +00:00
jhb
80d9458a56 Adjust some variables (mostly related to the buffer cache) that hold
address space sizes to be longs instead of ints.  Specifically, the follow
values are now longs: runningbufspace, bufspace, maxbufspace,
bufmallocspace, maxbufmallocspace, lobufspace, hibufspace, lorunningspace,
hirunningspace, maxswzone, maxbcache, and maxpipekva.  Previously, a
relatively small number (~ 44000) of buffers set in kern.nbuf would result
in integer overflows resulting either in hangs or bogus values of
hidirtybuffers and lodirtybuffers.  Now one has to overflow a long to see
such problems.  There was a check for a nbuf setting that would cause
overflows in the auto-tuning of nbuf.  I've changed it to always check and
cap nbuf but warn if a user-supplied tunable would cause overflow.

Note that this changes the ABI of several sysctls that are used by things
like top(1), etc., so any MFC would probably require a some gross shims
to allow for that.

MFC after:	1 month
2009-03-09 19:35:20 +00:00
trasz
644f63d68b Right now, when trying to unmount a device that's already gone,
msdosfs_unmount() and ffs_unmount() exit early after getting ENXIO.
However, dounmount() treats ENXIO as a success and proceeds with
unmounting.  In effect, the filesystem gets unmounted without closing
GEOM provider etc.

Reviewed by:	kib
Approved by:	rwatson (mentor)
Tested by:	dho
Sponsored by:	FreeBSD Foundation
2009-02-23 21:09:28 +00:00
trasz
40c2eac6aa Refactor, moving error checking outside of the
'if (mp->mnt_flag & MNT_SOFTDEP)' conditional.  No functional
changes.

Reviewed by:	kib
Approved by:	rwatson (mentor)
Tested by:	pho
Sponsored by:	FreeBSD Foundation
2009-02-23 20:56:27 +00:00
jhb
6f82ac1ceb - If the g_access() call for the initial root mount fails, then fully
cleanup.  Before the GEOM consumer would not have been closed.
- Bump the reference on the character device being mounted while the
  associated devfs vnode is locked.

Reviewed by:	kib
2009-02-11 22:19:54 +00:00
trasz
e0aa6f81f9 When a device containing mounted UFS filesystem disappears, the type
of devvp becomes VBAD, which UFS incorrectly interprets as snapshot
vnode, which in turns causes panic.  Fix it by replacing '!= VCHR'
with '== VREG'.

With this fix in place, you should no longer be able to panic the system
by removing a device with an UFS filesystem mounted from it - assuming
you don't use softupdates.

Reviewed by:	kib
Tested by:	pho
Approved by:	rwatson (mentor)
Sponsored by:	FreeBSD Foundation
2009-02-06 17:14:07 +00:00
trasz
d27cdd2fdd Make sure the cdev doesn't go away while the filesystem is still mounted.
Otherwise dev2udev() could return garbage.

Reviewed by:	kib
Approved by:	rwatson (mentor)
Sponsored by:	FreeBSD Foundation
2009-01-29 16:47:15 +00:00
rwatson
c99f201c9e Following a fair amount of real world experience with ACLs and
extended attributes since FreeBSD 5, make the following semantic
changes:

- Don't update the inode modification time (mtime) when extended
  attributes (and hence also ACLs) are added, modified, or removed.
- Don't update the inode access tie (atime) when extended attributes
  (and hence also ACLs) are queried.

This means that rsync (and related tools) won't improperly think
that the data in the file has changed when only the ACL has changed.

Note that ffs_reallocblks() has not been changed to not update on an
IO_EXT transaction, but currently EAs don't use the cluster write
routines so this shouldn't be a problem.  If EAs grow support for
clustering, then VOP_REALLOCBLKS() will need to grow a flag argument
to carry down IO_EXT to UFS.

MFC after:	1 week
PR:             ports/125739
Reported by:    Alexander Zagrebin <alexz@visp.ru>
Tested by:      pluknet <pluknet@gmail.com>,
                Greg Byshenk <freebsd@byshenk.net>
Discussed with: kib, kientzle, timur, Alexander Bokovoy <ab@samba.org>
2009-01-27 21:48:47 +00:00
jhb
2939c2f76f Fix a few style bogons.
Submitted by:	bde
2009-01-21 20:08:17 +00:00
kib
44eef9d9bb Move the code from ufs_lookup.c used to do dotdot lookup, into
the helper function. It is supposed to be useful for any filesystem
that has to unlock dvp to walk to the ".." entry in lookup routine.

Requested by:	jhb
Tested by:	pho
MFC after:	1 month
2009-01-21 14:51:38 +00:00
jhb
47455a7b41 Move the VA_MARKATIME flag for VOP_SETATTR() out into its own VOP:
VOP_MARKATIME() since unlike the rest of VOP_SETATTR(), VA_MARKATIME
can be performed while holding a shared vnode lock (the same functionality
is done internally by VOP_READ which can run with a shared vnode lock).
Add missing locking of the vnode interlock to the ufs implementation and
remove a special note and test from the NFS client about not supporting the
feature.

Inspired by:	ups
Tested by:	pho
2009-01-21 14:42:00 +00:00
kib
1a9032d339 The r187467 should remove all pages for V_NORMAL case too, because
indirect block pages are not removed by the mentioned invocation of
the vnode_pager_setsize().

Put a common code into the helper function ffs_pages_remove().

Reported and tested by:	dchagin
Reviewed by:	ups
MFC after:	3 weeks
2009-01-20 22:00:19 +00:00
jhb
19686e364d Add a comment explaining why the "bufwait" / "dirhash" LOR reported by
WITNESS will not actually result in a deadlock.

Discussed with:	kib
MFC after:	1 week
2009-01-20 16:35:34 +00:00
kib
ac57d6e717 When extending inode size, we call vnode_pager_setsize(), to have a
address space where to put vnode pages, and then call UFS_BALLOC(),
to actually allocate new block and map it. When UFS_BALLOC() returns
error, sometimes we forget to revert the vm object size increase,
allowing for the pages that are not backed by the logical disk blocks.

Revert vnode_pager_setsize() back when UFS_BALLOC() failed, for
ffs_truncate() and ffs_write().

PR:	129956
Reviewed by:	ups
MFC after:	3 weeks
2009-01-20 11:30:22 +00:00
kib
cbb8defa10 FFS puts the extended attributes blocks at the negative blocks for the
vnode, from -1 down. When vinvalbuf(vp, V_ALT) is done for the vnode, it
incorrectly does vm_object_page_remove(0, 0), removing all pages from
the underlying vm object, not only the pages that back the extended
attributes data.

Change vinvalbuf() to not remove any pages from the object when
V_NORMAL or V_ALT are specified. Instead, the only in-tree caller
in ffs_inode.c:ffs_truncate() that specifies V_ALT explicitely
removes the corresponding page range. The V_NORMAL caller
does vnode_pager_setsize(vp, 0) immediately after the call to
vinvalbuf(V_NORMAL) already.

Reported by:	csjp
Reviewed by:	ups
MFC after:	3 weeks
2009-01-20 11:27:45 +00:00
kib
ca2e9cb3a9 Lock the uepm_lock around the autostart of extattrs.
Reported and tested by:	pho
Reviewed by:	rwatson
MFC after:	3 weeks
2009-01-08 12:49:55 +00:00
kib
1f52da301f If unmount of the ffs mp failed, reinitialize the extended attributes
for the mp, and restart them if autostart is enabled.

Reported and tested by:	pho
Reviewed by:	rwatson
MFC after:	3 weeks
2009-01-08 12:48:27 +00:00
kib
068931a989 Do not busy twice the mount point where a quota operation is performed.
Tested by:	pho
MFC after:	1 month
2008-12-18 12:01:53 +00:00
trasz
b2515a861b According to phk@, VOP_STRATEGY should never, _ever_, return
anything other than 0.  Make it so.  This fixes
"panic: VOP_STRATEGY failed bp=0xc320dd90 vp=0xc3b9f648",
encountered when writing to an orphaned filesystem.  Reason
for the panic was the following assert:
KASSERT(i == 0, ("VOP_STRATEGY failed bp=%p vp=%p", bp, bp->b_vp));
at vfs_bio:bufstrategy().

Reviewed by:	scottl, phk
Approved by:	rwatson (mentor)
Sponsored by:	FreeBSD Foundation
2008-12-16 21:13:11 +00:00
kib
01085e085d The dqrele() function syncs the dq, then acquires the dqh lock, and then
does final drop of the the dq reference to put it onto the free list.
There is a possibility that the dq would be found by another thread
after sync and before the dqh lock is acquired. If that other thread
drops the dq before we have taken the dqh lock, the dirty dq is put on
the free list.

Recheck the DQ_MOD after the dqh lock is relocked. Repeat dqsync() if
the dq is dirty. This ensures that up to date dq is written in the quota
file and fixes assertion in dqget().

Reported and tested by:	Frode Nordahl <frode nordahl net>
MFC after:	3 days
2008-12-08 11:04:17 +00:00
kib
868630039f Improve usefulness of the panic by printing the pointer to the problematic
dquot. In-tree gdb is often unable to get the dq value, so supply it in
panic message.

MFC after:	3 days
2008-12-07 13:25:06 +00:00
kib
294fd952b0 Do not lock vnode interlock around reading of v_iflag to check VI_DOOMED.
Read of the pointer is atomic, and flag cannot be set while vnode lock
is held.

Requested by:	jhb
MFC after:	1 month
2008-12-02 11:12:50 +00:00
kib
371d0216fb Busy ufs filesystem around block of code that does ".." lookup. Since
mnt_lock is before lock of any vnode on the mp, it uses LK_NOWAIT. Since
MNTK_UNMOUNT may be transient, pdp lock is dropped when vfs_busy()
failed, and operation is retried after some time. This way, ffs_vget()
is not called on the mp that may be in the process of being destroyed by
unmount.

Check for the VI_DOOMED flag on pdp after its lock is reacquired, to
better detect some situations where directory containing ".."
entry is removed during the lookup.

Reviewed by:	tegge, attilio (previous version)
Tested by:	pho
MFC after:	1 month
2008-11-22 13:11:11 +00:00
jhb
f8948bf5ef Fix typo. 2008-11-19 20:06:59 +00:00
ambrisko
4ee5cbf821 For now on every 10 cyclinder groups flush the buffer cache to free
up space.  If the buffer cache fills up then the disk systems can
grind to a halt.  Better tuning can be figured out later.

Tested by:	Tim, others and work
Reviewed by:	Kostik Belousov
PR:		128832
2008-11-13 17:40:21 +00:00
jhb
9f264a6a75 Quiet a WITNESS warning with the dirhash sx locks by setting the DUPOK
flag.  Specifically, if two threads race to create a dirhash for a
directory, then one might already have created a private dirhash
structure (and locked it) when it realizes the directory now has a
structure and tries to lock that one.
2008-11-04 18:56:12 +00:00
trasz
5ff0dc16bf In UFS, when reading EA that contains ACL fails for some reason, include
inode number and filesystem name, so the administrator can fix the problem.

Approved by:	rwatson (mentor)
2008-11-04 12:30:31 +00:00
attilio
e1f493235e Improve VFS locking:
- Implement real draining for vfs consumers by not relying on the
  mnt_lock and using instead a refcount in order to keep track of lock
  requesters.
- Due to the change above, remove the mnt_lock lockmgr because it is now
  useless.
- Due to the change above, vfs_busy() is no more linked to a lockmgr.
  Change so its KPI by removing the interlock argument and defining 2 new
  flags for it: MBF_NOWAIT which basically replaces the LK_NOWAIT of the
  old version (which was unlinked from the lockmgr alredy) and
  MBF_MNTLSTLOCK which provides the ability to drop the mountlist_mtx
  once the mnt interlock is held (ability still desired by most consumers).
- The stub used into vfs_mount_destroy(), that allows to override the
  mnt_ref if running for more than 3 seconds, make it totally useless.
  Remove it as it was thought to work into older versions.
  If a problem of "refcount held never going away" should appear, we will
  need to fix properly instead than trust on such hackish solution.
- Fix a bug where returning (with an error) from dounmount() was still
  leaving the MNTK_MWAIT flag on even if it the waiters were actually
  woken up. Just a place in vfs_mount_destroy() is left because it is
  going to recycle the structure in any case, so it doesn't matter.
- Remove the markercnt refcount as it is useless.

This patch modifies VFS ABI and breaks KPI for vfs_busy() so manpages and
__FreeBSD_version will be modified accordingly.

Discussed with:	kib
Tested by:	pho
2008-11-02 10:15:42 +00:00