Commit Graph

459 Commits

Author SHA1 Message Date
jhb
0f8779b64e MFC 200084:
Properly return an error reply if an NFS remove or link operation fails.
Previously the failing operation would allocate an mbuf and construct an
error reply, but because the function did not return 0, the NFS server
assumed it had failed to generate a reply and would leak the reply mbuf as
well as not sending the reply to the NFS client.
2009-12-18 19:43:44 +00:00
marcel
a8f4dc3a07 MFC r199274, r199284:
Fix an obvious panic by not casting from a pointer that is 4-bytes
alignment to a type that needs 8-byte alignment, and thus causing
misaligned memory references.
2009-11-24 03:38:42 +00:00
pjd
ec3c13d92d MFC r197287, r197289, r197351, r197426, r197458, r197459, r197497, r197498,
r197512, r197513, r197514, r197515, r197525:

r197287:

Purge namecache for the file system being rolled back, so it doesn't point at
invalid vnodes after the rollback resulting in EIO errors when trying to access
files which are in the namecache.

Reported by:	des

r197289:

Purge file system namecache when receiving incremental stream and rolling back
to it.

r197351:

Purge namecache in the same place OpenSolaris does.

r197426:

Restore BSD behaviour - when creating new directory entry use parent directory
gid to set group ownership and not process gid.

This was overlooked during v6 -> v13 switch.

PR:	kern/139076
Reported by:	Sean Winn <sean@gothic.net.au>

r197458:

Close race in zfs_zget(). We have to increase usecount first and then
check for VI_DOOMED flag. Before this change vnode could be reclaimed
between checking for the flag and increasing usecount.

r197459:

Before calling vflush(FORCECLOSE) mark file system as unmounted so the
following vnops will fail. This is very important, because without this change
vnode could be reclaimed at any point, even if we increased usecount. The only
way to ensure that vnode won't be reclaimed was to lock it, which would be very
hard to do in ZFS without changing a lot of code. With this change simply
increasing usecount is enough to be sure vnode won't be reclaimed from under
us. To be precise it can still be reclaimed but we won't be able to see it,
because every try to enter ZFS through VFS will result in EIO.

The only function that cannot return EIO, because it is needed for vflush() is
zfs_root(). Introduce ZFS_ENTER_NOERROR() macro that only locks
z_teardown_lock and never returns EIO.

r197497:

Switch to fletcher4 as the default checksum algorithm. Fletcher2 was proven to
be a bit weak and OpenSolaris also switched to fletcher4.

r197498:	head/cddl/contrib/opensolaris

Fletcher4 is not the default checksum algorithm.

r197512:

- Don't depend on value returned by gfs_*_inactive(), it doesn't work
  well with forced unmounts when GFS vnodes are referenced.
- Make other preparations to GFS for forced unmounts.

PR:	kern/139062
Reported by:	trasz

r197513:

Use traverse() function to find and return mount point's vnode instead of
covered vnode when snapshot is already mounted.

r197514:

On lookup error VFS expects *vpp to be set to NULL, be sure to do that.

r197515:

Handle cases where virtual (GFS) vnodes are referenced when doing forced
unmount. In that case we cannot depend on the proper order of invalidating
vnodes, so we have to free resources when we have a chance.

PR:	kern/139062
Reported by:	trasz

r197525:

Ensure that tv_sec is between INT32_MIN and INT32_MAX, so ZFS won't object.
This completes the fix from r185586.

PR:	kern/139059
Reported by:	Daniel Braniss <danny@cs.huji.ac.il>
Submitted by:	Jaakko Heinonen <jh@saunalahti.fi>
Tested by:	Daniel Braniss <danny@cs.huji.ac.il>

Approved by:	re (kib)
2009-09-29 10:53:06 +00:00
pjd
2bb746183b MFC r197039, r197040:
Fix usecount leak in mknod(2) on file system exported over NFS.

While I'm here, correct typo in comment.

Reviewed by:	kan, kib
Approved by:	re (bz)
2009-09-15 11:20:23 +00:00
dfr
5d248bb05f Remove the old kernel RPC implementation and the NFS_LEGACYRPC option.
Approved by: re
2009-06-30 19:03:27 +00:00
jhb
ccb2608d06 Fix build with NFS_LEGACYRPC enabled after the socket upcall locking
changes.

Approved by:	re (kensmith)
2009-06-30 03:18:51 +00:00
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
rmacklem
d88296a89f Since svc_[dg|vc|tli|tp]_create() did not hold a reference count on the
SVCXPTR structure returned by them, it was possible for the structure
to be free'd before svc_reg() had been completed using the structure.
This patch acquires a reference count on the newly created structure
that is returned by svc_[dg|vc|tli|tp]_create(). It also
adds the appropriate SVC_RELEASE() calls to the callers, except the
experimental nfs subsystem. The latter will be committed separately.

Submitted by:	dfr
Tested by:	pho
Approved by:	kib (mentor)
2009-06-17 22:50:26 +00:00
rmacklem
9d4e4b79d9 Add a #include <sys/jail.h> so that it builds when
options KGSSAPI is specified in the kernel configuration.

Approved by:	kib (mentor)
2009-06-12 20:18:08 +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
jhb
a1af9ecca4 Rework socket upcalls to close some races with setup/teardown of upcalls.
- Each socket upcall is now invoked with the appropriate socket buffer
  locked.  It is not permissible to call soisconnected() with this lock
  held; however, so socket upcalls now return an integer value.  The two
  possible values are SU_OK and SU_ISCONNECTED.  If an upcall returns
  SU_ISCONNECTED, then the soisconnected() will be invoked on the
  socket after the socket buffer lock is dropped.
- A new API is provided for setting and clearing socket upcalls.  The
  API consists of soupcall_set() and soupcall_clear().
- To simplify locking, each socket buffer now has a separate upcall.
- When a socket upcall returns SU_ISCONNECTED, the upcall is cleared from
  the receive socket buffer automatically.  Note that a SO_SND upcall
  should never return SU_ISCONNECTED.
- All this means that accept filters should now return SU_ISCONNECTED
  instead of calling soisconnected() directly.  They also no longer need
  to explicitly clear the upcall on the new socket.
- The HTTP accept filter still uses soupcall_set() to manage its internal
  state machine, but other accept filters no longer have any explicit
  knowlege of socket upcall internals aside from their return value.
- The various RPC client upcalls currently drop the socket buffer lock
  while invoking soreceive() as a temporary band-aid.  The plan for
  the future is to add a new flag to allow soreceive() to be called with
  the socket buffer locked.
- The AIO callback for socket I/O is now also invoked with the socket
  buffer locked.  Previously sowakeup() would drop the socket buffer
  lock only to call aio_swake() which immediately re-acquired the socket
  buffer lock for the duration of the function call.

Discussed with:	rwatson, rmacklem
2009-06-01 21:17:03 +00:00
jamie
572db1408a Place hostnames and similar information fully under the prison system.
The system hostname is now stored in prison0, and the global variable
"hostname" has been removed, as has the hostname_mtx mutex.  Jails may
have their own host information, or they may inherit it from the
parent/system.  The proper way to read the hostname is via
getcredhostname(), which will copy either the hostname associated with
the passed cred, or the system hostname if you pass NULL.  The system
hostname can still be accessed directly (and without locking) at
prison0.pr_host, but that should be avoided where possible.

The "similar information" referred to is domainname, hostid, and
hostuuid, which have also become prison parameters and had their
associated global variables removed.

Approved by:	bz (mentor)
2009-05-29 21:27:12 +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
dfr
4bf244123e Fix build of KGSSAPI bits post-vimage. 2009-05-24 11:10:27 +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
bb19ddd3ae Change nfsserver so that it uses the nfssvc() system call provided
in sys/nfs/nfs_nfssvc.c by registering with it using the
	nfsd_call_nfsserver function pointer. Also, add the build glue for
	nfs_nfssvc.c optionally based on "nfsserver" and also as a loadable
	module.

Submitted by:	rmacklem
Reviewed by:	kib
Approved by:	kib (mentor)
2009-04-12 19:04:27 +00:00
dfr
41382eee31 Fix an mbuf leak in the error path.
Submitted by:	Rick Macklem <rick at snowhite dot cis dot uoguelph dot ca>
2009-03-19 14:13:18 +00:00
rwatson
ceb08f5693 Include audit.h so that the system call path protected by NFS_LEGACYRPC
can audit its arguments.

Submitted by:	Jaakko Heinonen <jh at saunalahti.fi>
MFC after:	1 week
X-MFC-note:	MFC with r188311
2009-02-23 23:04:15 +00:00
jhb
26e338d6fc Use shared vnode locks when invoking VOP_READDIR().
MFC after:	1 month
2009-02-13 18:18:14 +00:00
rwatson
4349e4002b Audit the flag argument to the nfssvc(2) system call.
Obtained from:	TrustedBSD Project
Sponsored by:	Apple, Inc.
2009-02-08 14:04:08 +00:00
ed
a964306db9 Last step of splitting up minor and unit numbers: remove minor().
Inside the kernel, the minor() function was responsible for obtaining
the device minor number of a character device. Because we made device
numbers dynamically allocated and independent of the unit number passed
to make_dev() a long time ago, it was actually a misnomer. If you really
want to obtain the device number, you should use dev2udev().

We already converted all the drivers to use dev2unit() to obtain the
device unit number, which is still used by a lot of drivers. I've
noticed not a single driver passes NULL to dev2unit(). Even if they
would, its behaviour would make little sense. This is why I've removed
the NULL check.

Ths commit removes minor(), minor2unit() and unit2minor() from the
kernel. Because there was a naming collision with uminor(), we can
rename umajor() and uminor() back to major() and minor(). This means
that the makedev(3) manual page also applies to kernel space code now.

I suspect umajor() and uminor() isn't used that often in external code,
but to make it easier for other parties to port their code, I've
increased __FreeBSD_version to 800062.
2009-01-28 17:57:16 +00:00
kensmith
7d088b7fca Handle VFS_VGET() failing with an error other than EOPNOTSUPP in addition
to failing with that error.

PR:		125149
Submitted by:	Jaakko Heinonen (jh <at> saunalahti <dot> fi)
Reviewed by:	mohans, kan
MFC after:	3 days
2008-12-16 04:34:09 +00:00
dfr
75eeed4f1f We need to pass a structure with enough space for an NFSv2 filehandle to
nfs_srvmtofh_xx otherwise bad things happen when an NFSv2 client tries to
make a request.
2008-12-10 14:49:54 +00:00
kan
c7b0520697 Change nfsserver slightly so that it does not trip over the timestamp
validation code on ZFS.

Problem: when opening file with O_CREAT|O_EXCL NFS has to jump through
extra hoops to ensure O_EXCL semantics. Namely, client supplies of 8
bytes (NFSX_V3CREATEVERF) bytes of verification data to uniquely
identify this create request. Server then creates a new file with access
mode 0, copies received 8 bytes into va_atime member of struct vattr and
attempt to set the atime on file using VOP_SETATTR. If that succeeds, it
fetches file attributes with VOP_GETATTR and verifies that atime
timestamps match.  If timestamps do not match, NFS server concludes it
has probbaly lost the race to another process creating the file with the
same name and bails with EEXIST.

This scheme works OK when exported FS is FFS, but if underlying
filesystem is ZFS _and_ server is running 64bit kernel, it breaks down
due to sanity checking in zfs_setattr function, which refuses to accept
any timestamps which have tv_sec that cannot be represented as 32bit
int. Since struct timespec fields are 64 bit integers on 64bit platforms
and server just copies NFSX_V3CREATEVERF bytes info va_atime, all eight
bytes supplied by client end up in va_atime.tv_sec, forcing it out of
valid 32bit range.

The solution this change implements is simple: it treats
NFSX_V3CREATEVERF as two 32bit integers and unpacks them separately into
va_atime.tv_sec and va_atime.tv_nsec respectively, thus guaranteeing
that tv_sec remains in 32 bit range and ZFS remains happy.

Reviewed by: kib
2008-12-03 17:54:09 +00:00
kib
bf74bb2e16 In the nfsrv_fhtovp(), after the vfs_getvfs() function found the pointer
to the fs, but before a vnode on the fs is locked, unmount may free fs
structures, causing access to destroyed data and freed memory.

Introduce a vfs_busymp() function that looks up and busies found
fs while mountlist_mtx is held. Use it in nfsrv_fhtovp() and in the
implementation of the handle syscalls.

Two other uses of the vfs_getvfs() in the vfs_subr.c, namely in
sysctl_vfs_ctl and vfs_getnewfsid seems to be ok. In particular,
sysctl_vfs_ctl is protected by Giant by being a non-sleeping sysctl
handler, that prevents Giant-locked unmount code to interfere with it.

Noted by:	tegge
Reviewed by:	dfr
Tested by:	pho
MFC after:	1 month
2008-11-29 13:34:59 +00:00
dfr
367ae23f20 Switch the default rpc implementation for NFS back to the new code. I believe
I have fixed the reported problems - if you still have trouble with it, please
contact me with as much detail as possible so that I can track down any other
issues as quickly as possible.
2008-11-14 11:27:53 +00:00
dfr
3b3a59e0c7 Use the remote address for access control, not the local address. This fixes
the nfsd problems that some people have with the new code.

Add support for the vfs.nfsrv.nfs_privport sysctl which denies access unless
the client is using a port number less than 1024. Not really sure if this is
particularly useful since it doesn't add any real security.
2008-11-13 14:36:52 +00:00
dfr
f2543b22e0 Temporarily switch NFS back to the old RPC code while I try to diagnose and
fix the problems a few people have noticed with the new code. People who want
to continue testing the new code or who need RPCSEC_GSS support should use
the new option NFS_NEWRPC to select it.
2008-11-13 11:35:18 +00:00
dfr
743ba239e7 Turn (NFSERR_AUTHERR|code) status values into svcerr_auth(rqst, code) replies
instead of returning a success with a bogus NFS error code.
2008-11-12 09:38:18 +00:00
dfr
dd7b0d73e4 Allow v3 GETATTR requests even when weakly authenticated. Change the error
return for for weakly authenticated requests from REJECTEDCRED to WEAKAUTH
for consistency with Solaris.
2008-11-12 09:36:35 +00:00
dfr
cc925302a0 Range-check NFSv2 procedure numbers before converting to NFSv3.
Submitted by:	csjp
2008-11-07 10:43:01 +00:00
dfr
ee8eea89ff Don't depend on krpc.ko in the NFS_LEGACYRPC case. 2008-11-06 11:43:49 +00:00
des
4cc1c2c89f Unbreak NFS.
Pointy hat to:	dfr
2008-11-06 10:53:35 +00:00
dfr
d070e7ad67 If mountd doesn't specify a secflavor list for the mount, assume that -sec=sys
is what was wanted.
2008-11-05 16:25:26 +00:00
dfr
aa144d95db Include <sys/eventhandler.h>. 2008-11-04 16:43:02 +00:00
dfr
2fb03513fc Implement support for RPCSEC_GSS authentication to both the NFS client
and server. This replaces the RPC implementation of the NFS client and
server with the newer RPC implementation originally developed
(actually ported from the userland sunrpc code) to support the NFS
Lock Manager.  I have tested this code extensively and I believe it is
stable and that performance is at least equal to the legacy RPC
implementation.

The NFS code currently contains support for both the new RPC
implementation and the older legacy implementation inherited from the
original NFS codebase. The default is to use the new implementation -
add the NFS_LEGACYRPC option to fall back to the old code. When I
merge this support back to RELENG_7, I will probably change this so
that users have to 'opt in' to get the new code.

To use RPCSEC_GSS on either client or server, you must build a kernel
which includes the KGSSAPI option and the crypto device. On the
userland side, you must build at least a new libc, mountd, mount_nfs
and gssd. You must install new versions of /etc/rc.d/gssd and
/etc/rc.d/nfsd and add 'gssd_enable=YES' to /etc/rc.conf.

As long as gssd is running, you should be able to mount an NFS
filesystem from a server that requires RPCSEC_GSS authentication. The
mount itself can happen without any kerberos credentials but all
access to the filesystem will be denied unless the accessing user has
a valid ticket file in the standard place (/tmp/krb5cc_<uid>). There
is currently no support for situations where the ticket file is in a
different place, such as when the user logged in via SSH and has
delegated credentials from that login. This restriction is also
present in Solaris and Linux. In theory, we could improve this in
future, possibly using Brooks Davis' implementation of variant
symlinks.

Supporting RPCSEC_GSS on a server is nearly as simple. You must create
service creds for the server in the form 'nfs/<fqdn>@<REALM>' and
install them in /etc/krb5.keytab. The standard heimdal utility ktutil
makes this fairly easy. After the service creds have been created, you
can add a '-sec=krb5' option to /etc/exports and restart both mountd
and nfsd.

The only other difference an administrator should notice is that nfsd
doesn't fork to create service threads any more. In normal operation,
there will be two nfsd processes, one in userland waiting for TCP
connections and one in the kernel handling requests. The latter
process will create as many kthreads as required - these should be
visible via 'top -H'. The code has some support for varying the number
of service threads according to load but initially at least, nfsd uses
a fixed number of threads according to the value supplied to its '-n'
option.

Sponsored by:	Isilon Systems
MFC after:	1 month
2008-11-03 10:38:00 +00:00
trhodes
3c9c77e154 Document a few sysctls in the NFS client and server code.
Minor style(9) where applicable.

Approved by:	alfred (slightly older version)
2008-11-02 17:00:23 +00:00
trasz
0ad8692247 Introduce accmode_t. This is required for NFSv4 ACLs - it will be neccessary
to add more V* constants, and the variables changed by this patch were often
being assigned to mode_t variables, which is 16 bit.

Approved by:	rwatson (mentor)
2008-10-28 13:44:11 +00:00
rwatson
a2129bd144 Rename three MAC entry points from _proc_ to _cred_ to reflect the fact
that they operate directly on credentials: mac_proc_create_swapper(),
mac_proc_create_init(), and mac_proc_associate_nfsd().  Update policies.

Obtained from:	TrustedBSD Project
2008-10-28 11:33:06 +00:00
des
66f807ed8b Retire the MALLOC and FREE macros. They are an abomination unto style(9).
MFC after:	3 months
2008-10-23 15:53:51 +00:00
rwatson
25ed07a2fe Turn XXX's for unlocked writes of NFS server statistics to simple notes,
as we consider it a feature to exchange performance for consistency.

MFC after:	3 days
2008-10-12 20:06:59 +00:00
attilio
23ff3dbeb8 Remove the suser(9) interface from the kernel. It has been replaced from
years by the priv_check(9) interface and just very few places are left.
Note that compatibility stub with older FreeBSD version
(all above the 8 limit though) are left in order to reduce diffs against
old versions. It is responsibility of the maintainers for any module, if
they think it is the case, to axe out such cases.

This patch breaks KPI so __FreeBSD_version will be bumped into a later
commit.

This patch needs to be credited 50-50 with rwatson@ as he found time to
explain me how the priv_check() works in detail and to review patches.

Tested by:      Giovanni Trematerra <giovanni dot trematerra at gmail dot com>
Reviewed by:    rwatson
2008-09-17 15:49:44 +00:00
attilio
a9873f87a6 Decontext-alize the nfsserver module.
Now, only some few places still require thread passing (mostly the ones which
access to VOP_* functions) and will be fixed once the primitive also will be.

Tested by:	Giovanni Trematerra <giovanni dot trematerra at gmail dot com>
2008-09-16 21:57:39 +00:00
attilio
dbf35e279f Decontextualize the couplet VOP_GETATTR / VOP_SETATTR as the passed thread
was always curthread and totally unuseful.

Tested by: Giovanni Trematerra <giovanni dot trematerra at gmail dot com>
2008-08-28 15:23:18 +00:00
rwatson
8805d22e34 Remove spls from NFS server setup call; expand receive socket buffer
locking to cover full setup of socket upcalls; remove XXX about
locking.

MFC after:	3 weeks
2008-06-30 20:43:06 +00:00
kib
f4b9bd396a Change the fix in the rev. 1.179 to use nfsrv_lockedpair_nd().
Tested by:	pho
MFC after:	3 days
2008-05-28 16:23:17 +00:00
kib
2e00a34c1d Initialize vfslocked prior to calling nfsm_srvmtofh where it was forgotten.
Reported by:	Andrew Edwards <aedwards sandvine com>
Tested by:	pho
MFC after:	3 days
2008-05-28 16:21:32 +00:00
ru
3b1bf8c2e9 Replaced the misleading uses of a historical artefact M_TRYWAIT with M_WAIT.
Removed dead code that assumed that M_TRYWAIT can return NULL; it's not true
since the advent of MBUMA.

Reviewed by:	arch

There are ongoing disputes as to whether we want to switch to directly using
UMA flags M_WAITOK/M_NOWAIT for mbuf(9) allocation.
2008-03-25 09:39:02 +00:00
jeff
a9d123c3ab - Complete part of the unfinished bufobj work by consistently using
BO_LOCK/UNLOCK/MTX when manipulating the bufobj.
 - Create a new lock in the bufobj to lock bufobj fields independently.
   This leaves the vnode interlock as an 'identity' lock while the bufobj
   is an io lock.  The bufobj lock is ordered before the vnode interlock
   and also before the mnt ilock.
 - Exploit this new lock order to simplify softdep_check_suspend().
 - A few sync related functions are marked with a new XXX to note that
   we may not properly interlock against a non-zero bv_cnt when
   attempting to sync all vnodes on a mountlist.  I do not believe this
   race is important.  If I'm wrong this will make these locations easier
   to find.

Reviewed by:	kib (earlier diff)
Tested by:	kris, pho (earlier diff)
2008-03-22 09:15:16 +00:00