The kernel has a special wchan called `lbolt', which is triggered each
second. It doesn't seem to be used a lot and it seems pretty redundant,
because we can specify a timeout value to the *sleep() routines. In an
attempt to eventually remove lbolt, make the NFS/RPC code use a timeout
of `hz' when trying to reconnect.
Only the TTY code (not MPSAFE TTY) and the VFS syncer seem to use lbolt
now.
Reviewed by: attilio, jhb
Approved by: philip (mentor), alfred, dfr
to global hostname and domainname variables. Where necessary, copy
to or from a stack-local buffer before performing copyin() or
copyout(). A few uses, such as in cd9660 and daemon_saver, remain
under-synchronized and will require further updates.
Correct a bug in which a failed copyin() of domainname would leave
domainname potentially corrupted.
MFC after: 3 weeks
provides the correct semantics for flock(2) style locks which are used by the
lockf(1) command line tool and the pidfile(3) library. It also implements
recovery from server restarts and ensures that dirty cache blocks are written
to the server before obtaining locks (allowing multiple clients to use file
locking to safely share data).
Sponsored by: Isilon Systems
PR: 94256
MFC after: 2 weeks
This particular implementation is designed to be fully backwards compatible
and to be MFC-able to 7.x (and 6.x)
Currently the only protocol that can make use of the multiple tables is IPv4
Similar functionality exists in OpenBSD and Linux.
From my notes:
-----
One thing where FreeBSD has been falling behind, and which by chance I
have some time to work on is "policy based routing", which allows
different
packet streams to be routed by more than just the destination address.
Constraints:
------------
I want to make some form of this available in the 6.x tree
(and by extension 7.x) , but FreeBSD in general needs it so I might as
well do it in -current and back port the portions I need.
One of the ways that this can be done is to have the ability to
instantiate multiple kernel routing tables (which I will now
refer to as "Forwarding Information Bases" or "FIBs" for political
correctness reasons). Which FIB a particular packet uses to make
the next hop decision can be decided by a number of mechanisms.
The policies these mechanisms implement are the "Policies" referred
to in "Policy based routing".
One of the constraints I have if I try to back port this work to
6.x is that it must be implemented as a EXTENSION to the existing
ABIs in 6.x so that third party applications do not need to be
recompiled in timespan of the branch.
This first version will not have some of the bells and whistles that
will come with later versions. It will, for example, be limited to 16
tables in the first commit.
Implementation method, Compatible version. (part 1)
-------------------------------
For this reason I have implemented a "sufficient subset" of a
multiple routing table solution in Perforce, and back-ported it
to 6.x. (also in Perforce though not always caught up with what I
have done in -current/P4). The subset allows a number of FIBs
to be defined at compile time (8 is sufficient for my purposes in 6.x)
and implements the changes needed to allow IPV4 to use them. I have not
done the changes for ipv6 simply because I do not need it, and I do not
have enough knowledge of ipv6 (e.g. neighbor discovery) needed to do it.
Other protocol families are left untouched and should there be
users with proprietary protocol families, they should continue to work
and be oblivious to the existence of the extra FIBs.
To understand how this is done, one must know that the current FIB
code starts everything off with a single dimensional array of
pointers to FIB head structures (One per protocol family), each of
which in turn points to the trie of routes available to that family.
The basic change in the ABI compatible version of the change is to
extent that array to be a 2 dimensional array, so that
instead of protocol family X looking at rt_tables[X] for the
table it needs, it looks at rt_tables[Y][X] when for all
protocol families except ipv4 Y is always 0.
Code that is unaware of the change always just sees the first row
of the table, which of course looks just like the one dimensional
array that existed before.
The entry points rtrequest(), rtalloc(), rtalloc1(), rtalloc_ign()
are all maintained, but refer only to the first row of the array,
so that existing callers in proprietary protocols can continue to
do the "right thing".
Some new entry points are added, for the exclusive use of ipv4 code
called in_rtrequest(), in_rtalloc(), in_rtalloc1() and in_rtalloc_ign(),
which have an extra argument which refers the code to the correct row.
In addition, there are some new entry points (currently called
rtalloc_fib() and friends) that check the Address family being
looked up and call either rtalloc() (and friends) if the protocol
is not IPv4 forcing the action to row 0 or to the appropriate row
if it IS IPv4 (and that info is available). These are for calling
from code that is not specific to any particular protocol. The way
these are implemented would change in the non ABI preserving code
to be added later.
One feature of the first version of the code is that for ipv4,
the interface routes show up automatically on all the FIBs, so
that no matter what FIB you select you always have the basic
direct attached hosts available to you. (rtinit() does this
automatically).
You CAN delete an interface route from one FIB should you want
to but by default it's there. ARP information is also available
in each FIB. It's assumed that the same machine would have the
same MAC address, regardless of which FIB you are using to get
to it.
This brings us as to how the correct FIB is selected for an outgoing
IPV4 packet.
Firstly, all packets have a FIB associated with them. if nothing
has been done to change it, it will be FIB 0. The FIB is changed
in the following ways.
Packets fall into one of a number of classes.
1/ locally generated packets, coming from a socket/PCB.
Such packets select a FIB from a number associated with the
socket/PCB. This in turn is inherited from the process,
but can be changed by a socket option. The process in turn
inherits it on fork. I have written a utility call setfib
that acts a bit like nice..
setfib -3 ping target.example.com # will use fib 3 for ping.
It is an obvious extension to make it a property of a jail
but I have not done so. It can be achieved by combining the setfib and
jail commands.
2/ packets received on an interface for forwarding.
By default these packets would use table 0,
(or possibly a number settable in a sysctl(not yet)).
but prior to routing the firewall can inspect them (see below).
(possibly in the future you may be able to associate a FIB
with packets received on an interface.. An ifconfig arg, but not yet.)
3/ packets inspected by a packet classifier, which can arbitrarily
associate a fib with it on a packet by packet basis.
A fib assigned to a packet by a packet classifier
(such as ipfw) would over-ride a fib associated by
a more default source. (such as cases 1 or 2).
4/ a tcp listen socket associated with a fib will generate
accept sockets that are associated with that same fib.
5/ Packets generated in response to some other packet (e.g. reset
or icmp packets). These should use the FIB associated with the
packet being reponded to.
6/ Packets generated during encapsulation.
gif, tun and other tunnel interfaces will encapsulate using the FIB
that was in effect withthe proces that set up the tunnel.
thus setfib 1 ifconfig gif0 [tunnel instructions]
will set the fib for the tunnel to use to be fib 1.
Routing messages would be associated with their
process, and thus select one FIB or another.
messages from the kernel would be associated with the fib they
refer to and would only be received by a routing socket associated
with that fib. (not yet implemented)
In addition Netstat has been edited to be able to cope with the
fact that the array is now 2 dimensional. (It looks in system
memory using libkvm (!)). Old versions of netstat see only the first FIB.
In addition two sysctls are added to give:
a) the number of FIBs compiled in (active)
b) the default FIB of the calling process.
Early testing experience:
-------------------------
Basically our (IronPort's) appliance does this functionality already
using ipfw fwd but that method has some drawbacks.
For example,
It can't fully simulate a routing table because it can't influence the
socket's choice of local address when a connect() is done.
Testing during the generating of these changes has been
remarkably smooth so far. Multiple tables have co-existed
with no notable side effects, and packets have been routes
accordingly.
ipfw has grown 2 new keywords:
setfib N ip from anay to any
count ip from any to any fib N
In pf there seems to be a requirement to be able to give symbolic names to the
fibs but I do not have that capacity. I am not sure if it is required.
SCTP has interestingly enough built in support for this, called VRFs
in Cisco parlance. it will be interesting to see how that handles it
when it suddenly actually does something.
Where to next:
--------------------
After committing the ABI compatible version and MFCing it, I'd
like to proceed in a forward direction in -current. this will
result in some roto-tilling in the routing code.
Firstly: the current code's idea of having a separate tree per
protocol family, all of the same format, and pointed to by the
1 dimensional array is a bit silly. Especially when one considers that
there is code that makes assumptions about every protocol having the
same internal structures there. Some protocols don't WANT that
sort of structure. (for example the whole idea of a netmask is foreign
to appletalk). This needs to be made opaque to the external code.
My suggested first change is to add routing method pointers to the
'domain' structure, along with information pointing the data.
instead of having an array of pointers to uniform structures,
there would be an array pointing to the 'domain' structures
for each protocol address domain (protocol family),
and the methods this reached would be called. The methods would have
an argument that gives FIB number, but the protocol would be free
to ignore it.
When the ABI can be changed it raises the possibilty of the
addition of a fib entry into the "struct route". Currently,
the structure contains the sockaddr of the desination, and the resulting
fib entry. To make this work fully, one could add a fib number
so that given an address and a fib, one can find the third element, the
fib entry.
Interaction with the ARP layer/ LL layer would need to be
revisited as well. Qing Li has been working on this already.
This work was sponsored by Ironport Systems/Cisco
Reviewed by: several including rwatson, bz and mlair (parts each)
Obtained from: Ironport systems/Cisco
for better structure.
Much of this is related to <sys/clock.h>, which should really have
been called <sys/calendar.h>, but unless and until we need the name,
the repocopy can wait.
In general the kernel does not know about minutes, hours, days,
timezones, daylight savings time, leap-years and such. All that
is theoretically a matter for userland only.
Parts of kernel code does however care: badly designed filesystems
store timestamps in local time and RTC chips almost universally
track time in a YY-MM-DD HH:MM:SS format, and sometimes in local
timezone instead of UTC. For this we have <sys/clock.h>
<sys/time.h> on the other hand, deals with time_t, timeval, timespec
and so on. These know only seconds and fractions thereof.
Move inittodr() and resettodr() prototypes to <sys/time.h>.
Retain the names as it is one of the few surviving PDP/VAX references.
Move startrtclock() to <machine/clock.h> on relevant platforms, it
is a MD call between machdep.c/clock.c. Remove references to it
elsewhere.
Remove a lot of unnecessary <sys/clock.h> includes.
Move the machdep.disable_rtc_set sysctl to subr_rtc.c where it belongs.
XXX: should be kern.disable_rtc_set really, it's not MD.
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)
mount options that mount_nfs could pass down, if it passed
down string mount options. Right now, mount_nfs jut passes
down a single mount option named "nfs_args" with a fully
initialized 'struct nfs_args'.
In future commits, we will add code to the kernel for parsing stringified
NFS mount options, so that we can convert mount_nfs to pass string options
from userspace to kernel, instead of an initialized struct nfs_args.
the same way that it is default initialized in revision 1.77 of mount_nfs.c.
Right now, this is a no-op, because currently we initialize
struct nfs_args in mount_nfs in userspace, and pass it
down into the kernel via nmount(), so we overwrite whatever we initialize
here with the value passed in from userspace.
However, this lays the groundwork for moving away from passing
struct nfs_args from userspace to kernel via nmount(), so that we
can instead pass string mount options via nmount() which can be parsed in
the kernel. This will make it easier to add new NFS mount options.
always curthread.
As KPI gets broken by this patch, manpages and __FreeBSD_version will be
updated by further commits.
Tested by: Andrea Barberio <insomniac at slackware dot it>
file system. In particular, stop overwriting mount point
flags in nfs_mountdiskless() because now they are set
elsewhere. (They were _initialized_ by that function in
the 4.4BSD days, when mount structures were not allocated
in a centralized manner -- see rev. 1.1 of this file.)
Fix nfs_mount(), which happened to depend on the loss of
MNT_ROOTFS when it came to update handling.
Also note that mountnfs() no longer handles updates. Now
they shouldn't reach this function, so printf a diagnostic
message if that happens due to a coding error.
VOP_ISLOCKED(arg, curthread). Now, VOP_ISLOCKED() and lockstatus() should
only acquire curthread as argument; this will lead in axing the additional
argument from both functions, making the code cleaner.
Reviewed by: jeff, kib
conjuction with 'thread' argument passing which is always curthread.
Remove the unuseful extra-argument and pass explicitly curthread to lower
layer functions, when necessary.
KPI results broken by this change, which should affect several ports, so
version bumping and manpage update will be further committed.
Tested by: kris, pho, Diego Sardina <siarodx at gmail dot com>
noatime, noexec, suiddir, nosuid, nosymfollow, union,
noclusterr, noclusterw, multilabel, acls, force, update,
async. These options correspond to MOPT_STDOPTS, MOPT_FORCE, MOPT_UPDATE,
and MOPT_ASYNC.
Currently, mount_nfs converts these "-o" options from strings
to MNT_ flags via getmntopts(),
and passes the flags from userspace to the kernel.
This change will allow us in future to pass these mount options
as strings directly to the kernel via nmount() when doing NFS mounts.
previously conditionally acquired Giant based on debug.mpsafenet. As that
has now been removed, they are no longer required. Removing them
significantly simplifies error-handling in the socket layer, eliminated
quite a bit of unwinding of locking in error cases.
While here clean up the now unneeded opt_net.h, which previously was used
for the NET_WITH_GIANT kernel option. Clean up some related gotos for
consistency.
Reviewed by: bz, csjp
Tested by: kris
Approved by: re (kensmith)
SOCK_DGRAM (i.e. UDP), respect the value configured earlier. This allows
TCP NFS root mounts using e.g. the boot.nfsroot.options="tcp" tunable.
In this case some of the connection parameters like the retry timer were
previously set appropriately for TCP but inappropriately for the UDP
socket that was actually used, leading to e.g. extremely long recovery
times (O(hours)) after a nfs server reboot.
Reviewed by: mohans
MFC After: 2 weeks
of duplicating it except for larger style bugs in the copy.
Fix some nearby style bugs (including a harmless type mismatch)
in and near the remaining copy.
This is part of fixing collisions of the 2 nfs*client's names. Even
static names should have a unique prefixes so that they can be debugged
easily.
adds a FS type specific flag indicating that the FS supports shared
vnode lock lookups, adds some logic in vfs_lookup.c to test this flag
and set lock flags appropriately.
- amd on 6.x is a non-starter (without this change). Using amd under
heavy load results in a deadlock (with cascading vnode locks all the
way to the root) very quickly.
- This change should also fix the more general problem of cascading
vnode deadlocks when an NFS server goes down.
Ideally, we wouldn't need these changes, as enabling shared vnode lock
lookups globally would work. Unfortunately, UFS, for example isn't
ready for shared vnode lock lookups, crashing pretty quickly.
This change is the result of discussions with Stephan Uphoff (ups@).
Reviewed by: ups@
set the MTU prior to mounting root via NFS. This is required if the
server supports a higher than default MTU because the client will not
see the responses otherwise.
MFC after: 3 weeks
mimicing the NFS reference implementation.
NFS over TCP does not need fast retransmit timeouts, since network loss
and congestion are managed by the transport (TCP), unlike with NFS over
UDP. A long timeout prevents the unnecessary retransmission of non-
idempotent NFS requests.
Reviewed by: mohans, silby, rees?
Sponsored by: Network Appliance, Incorporated
vnode after vflush() has succeeded. This would cause a dangling vnode
panic at unmount time otherwise. Other filesystems may have this problem
via their VFS_VGET() routines.
Found by: kris
Sponsored by: Isilon Systems, Inc.
- Prefer '_' to ' ', as it results in more easily parsed results in
memory monitoring tools such as vmstat.
- Remove punctuation that is incompatible with using memory type names
as file names, such as '/' characters.
- Disambiguate some collisions by adding subsystem prefixes to some
memory types.
- Generally prefer lower case to upper case.
- If the same type is defined in multiple architecture directories,
attempt to use the same name in additional cases.
Not all instances were caught in this change, so more work is required to
finish this conversion. Similar changes are required for UMA zone names.
atomic write request, it can fill the buffer cache with the entirety
of that write in order to handle retries. However, it never drops
the vnode lock, or else it wouldn't be atomic, so it ends up waiting
indefinitely for more buf memory that cannot be gotten as it has it
all, and it waits in an uncancellable state.
To fix this, hibufspace is exported and scaled to a reasonable
fraction. This is used as the limit of how much of an atomic write
request by the NFS client will be handled asynchronously. If the
request is larger than this, it will be turned into a synchronous
request which won't deadlock the system. It's possible this value is
far off from what is required by some, so it shall be tunable as soon
as mount_nfs(8) learns of the new field.
The slowdown between an asynchronous and a synchronous write on NFS
appears to be on the order of 2x-4x.
General nod by: gad
MFC after: 2 weeks
More testing: wes
PR: kern/79208
as they have no connection with the expected MNT_* flags. This bug
was exposed 18 months ago when the assignments to f_flags in
vfs_syscalls.c were moved to before the VFS_STATFS() call. It was
fixed in the CSRG source 10 years ago, but we never picked up that
change.
PR: kern/80390
MFC after: 1 week
the MNT_RDONLY flag if the "ro" option was passed in from userland, and
clears it otherwise. In the diskless case, the MNT_RDONLY flag is already
set when this code is reached, but there are no mount options, so it was
incorrectly cleared. Change the logic so the MNT_RDONLY flag is set if the
"ro" option was specified, and left alone otherwise.
Note that the NFS code will still happily let you mount a filesystem RW
even if the server exports it RO. I'm not sure how to fix that.
these filesystems will support shared locks until they are explicitly
modified to do so. Careful review must be done to ensure that this
is safe for each individual filesystem.
Sponsored by: Isilon Systems, Inc.
and tweaks. The code was actually quite broken because it discarded the
upper bits of the 64 bit division. We only had a 50% chance of scaling up
the blocksize for large NFS client mounts when it was needed. For 5.x and
beyond, this was harmless because we could represent the result in either
case. For 4.x this was a big problem though. (4.x also has a df(1) bug to
compound the problem)
I'm not sure why a credential was added to these in the first place, it is
not used anywhere and it doesn't make much sense:
The credentials for syncing a file (ability to write to the
file) should be checked at the system call level.
Credentials for syncing one or more filesystems ("none")
should be checked at the system call level as well.
If the filesystem implementation needs a particular credential
to carry out the syncing it would logically have to the
cached mount credential, or a credential cached along with
any delayed write data.
Discussed with: rwatson
- NFS direct IO completely bypasses the buffer and page caches.
If a file is open for direct IO all caching is disabled.
- Direct IO for Directories will be addressed later.
- 2 new NFS directio related sysctls are added. One is a knob to
disable NFS direct IO completely (direct IO is enabled by default).
The other is to disallow mmaped IO on a file that has at least one
O_DIRECT open (see the comment in nfs_vnops.c for more details).
The default is to allow mmaps on a file that has O_DIRECT opens.
Submitted by: Mohan Srinivasan mohans at yahoo-inc dot com
Obtained from: Yahoo!
split the conversion of the remaining three filesystems out from the root
mounting changes, so in one go:
cd9660:
Convert to nmount.
Add omount compat shims.
Remove dedicated rootfs mounting code.
Use vfs_mountedfrom()
Rely on vfs_mount.c calling VFS_STATFS()
nfs(client):
Convert to nmount (the simple way, mount_nfs(8) is still necessary).
Add omount compat shims.
Drop COMPAT_PRELITE2 mount arg compatibility.
ffs:
Convert to nmount.
Add omount compat shims.
Remove dedicated rootfs mounting code.
Use vfs_mountedfrom()
Rely on vfs_mount.c calling VFS_STATFS()
Remove vfs_omount() method, all filesystems are now converted.
Remove MNTK_WANTRDWR, handling RO/RW conversions is a filesystem
task, and they all do it now.
Change rootmounting to use DEVFS trampoline:
vfs_mount.c:
Mount devfs on /. Devfs needs no 'from' so this is clean.
symlink /dev to /. This makes it possible to lookup /dev/foo.
Mount "real" root filesystem on /.
Surgically move the devfs mountpoint from under the real root
filesystem onto /dev in the real root filesystem.
Remove now unnecessary getdiskbyname().
kern_init.c:
Don't do devfs mounting and rootvnode assignment here, it was
already handled by vfs_mount.c.
Remove now unused bdevvp(), addaliasu() and addalias(). Put the
few necessary lines in devfs where they belong. This eliminates the
second-last source of bogo vnodes, leaving only the lemming-syncer.
Remove rootdev variable, it doesn't give meaning in a global context and
was not trustworth anyway. Correct information is provided by
statfs(/).
upcalls which do RPC header parsing and match up the reply with the
request. NFS calls now sleep on the nfsreq structure. This enables
us to eliminate the NFS recvlock.
Submitted by: Mohan Srinivasan mohans at yahoo-inc dot com
and annotate that nfs_mountroot assumes it is OK to step on the
values in the global NFSv3 diskless structure as the mountroot
function is called during a serialized part of the boot, before
any other NFS client activity occurs.
MFC after: 2 weeks
doesn't. Most of the implementations have grown weeds for this so they
copy some fields from mnt_stat if the passed argument isn't that.
Fix this the cleaner way: Always call the implementation on mnt_stat
and copy that in toto to the VFS_STATFS argument if different.
returned back to df from a statfs call. Causing df to print negative
values.
Submitted by: Mohan Srinivasan mohans at yahoo-inc dot com
Reviewed by: rwatson
Initialize b_bufobj for all buffers.
Make incore() and gbincore() take a bufobj instead of a vnode.
Make inmem() local to vfs_bio.c
Change a lot of VI_[UN]LOCK(bp->b_vp) to BO_[UN]LOCK(bp->b_bufobj)
also VI_MTX() to BO_MTX(),
Make buf_vlist_add() take a bufobj instead of a vnode.
Eliminate other uses of bp->b_vp where bp->b_bufobj will do.
Various minor polishing: remove "register", turn panic into KASSERT,
use new function declarations, TAILQ_FOREACH_SAFE() etc.
and refuse initializing filesystems with a wrong version. This will
aid maintenance activites on the 5-stable branch.
s/vfs_mount/vfs_omount/
s/vfs_nmount/vfs_mount/
Name our filesystems mount function consistently.
Eliminate the namiedata argument to both vfs_mount and vfs_omount.
It was originally there to save stack space. A few places abused
it to get hold of some credentials to pass around. Effectively
it is unused.
Reorganize the root filesystem selection code.
Add local rootvp variables as needed.
Remove checks for miniroot's in the swappartition. We never did that
and most of the filesystems could never be used for that, but it had
still been copy&pasted all over the place.
This is to allow filesystems to decide based on the passed thread
which vnode to return.
Several filesystems used curthread, they now use the passed thread.
bootp -> BOOTP
bootp.nfsroot -> BOOTP_NFSROOT
bootp.nfsv3 -> BOOTP_NFSV3
bootp.compat -> BOOTP_COMPAT
bootp.wired_to -> BOOTP_WIRED_TO
- i.e. back out the previous commit. It's already possible to
pxeboot(8) with a GENERIC kernel.
Pointed out by: dwmalone
BOOTP -> bootp
BOOTP_NFSROOT -> bootp.nfsroot
BOOTP_NFSV3 -> bootp.nfsv3
BOOTP_COMPAT -> bootp.compat
BOOTP_WIRED_TO -> bootp.wired_to
This lets you PXE boot with a GENERIC kernel by putting this sort of thing
in loader.conf:
bootp="YES"
bootp.nfsroot="YES"
bootp.nfsv3="YES"
bootp.wired_to="bge1"
or even setting the variables manually from the OK prompt.
Rebind the client socket when we experience a timeout. This fixes
the case where our IP changes for some reason.
Signal a VFS event when NFS transitions from up to down and vice
versa.
Add a placeholder vfs_sysctl where we will put status reporting
shortly.
Also:
Make down NFS mounts return EIO instead of EINTR when there is a
soft timeout or force unmount in progress.
our cached 'next vnode' being removed from this mountpoint. If we
find that it was recycled, we restart our traversal from the start
of the list.
Code to do that is in all local disk filesystems (and a few other
places) and looks roughly like this:
MNT_ILOCK(mp);
loop:
for (vp = TAILQ_FIRST(&mp...);
(vp = nvp) != NULL;
nvp = TAILQ_NEXT(vp,...)) {
if (vp->v_mount != mp)
goto loop;
MNT_IUNLOCK(mp);
...
MNT_ILOCK(mp);
}
MNT_IUNLOCK(mp);
The code which takes vnodes off a mountpoint looks like this:
MNT_ILOCK(vp->v_mount);
...
TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes);
...
MNT_IUNLOCK(vp->v_mount);
...
vp->v_mount = something;
(Take a moment and try to spot the locking error before you read on.)
On a SMP system, one CPU could have removed nvp from our mountlist
but not yet gotten to assign a new value to vp->v_mount while another
CPU simultaneously get to the top of the traversal loop where it
finds that (vp->v_mount != mp) is not true despite the fact that
the vnode has indeed been removed from our mountpoint.
Fix:
Introduce the macro MNT_VNODE_FOREACH() to traverse the list of
vnodes on a mountpoint while taking into account that vnodes may
be removed from the list as we go. This saves approx 65 lines of
duplicated code.
Split the insmntque() which potentially moves a vnode from one mount
point to another into delmntque() and insmntque() which does just
what the names say.
Fix delmntque() to set vp->v_mount to NULL while holding the
mountpoint lock.
functions in kern_socket.c.
Rename the "canwait" field to "mflags" and pass M_WAITOK and M_NOWAIT
in from the caller context rather than "1" or "0".
Correct mflags pass into mac_init_socket() from previous commit to not
include M_ZERO.
Submitted by: sam
and the nfs3 client. Also fix some bugs that happen to be causing crashes
in both v3 and v4 introduced by the v4 import.
Submitted by: Jim Rees <rees@umich.edu>
Approved by: re
vfs_mount_alloc/vfs_mount_destroy functions and take care to completely
destroy the mount point along with its locks. Mount struct has grown in
coplexity recently and depending on each failure path to destroy it
completely isn't working anymore.
2. Eliminate largely identical vfs_mount and vfs_unmount question by
moving the code to handle both cases into a newly introduced vfs_domount
function.
3. Simplify nfs_mount_diskless to always expect an allocated mount
struct and never attempt an allocation/destruction itself. The
vfs_allocroot allocation was there to support 'magic' swap space
configuration for diskless clients that was already removed by PHK some
time ago.
4. Include a vfs_buildopts cleanups by Peter Edwards to validate the
sanity of nmount parameters passed from userland.
Submitted by: (4) Peter Edwards <peter.edwards@openet-telecom.com>
Reviewed by: rwatson
Introduce two new macros MNT_ILOCK(mp)/MNT_IUNLOCK(mp) to
operate on this mutex transparently.
Eventually new mutex will be protecting more fields in
struct mount, not only vnode list.
Discussed with: jeff
wasn't curthread, i.e. when we receive a thread pointer to use
as a function argument. Use VOP_UNLOCK/vrele in these cases.
The only case there td != curthread known at the moment is
boot() calling sync with thread0 pointer.
This fixes the panic on shutdown people have reported.
This code dates back to the very first diskless support on FreeBSD,
back when swapon(8) couldn't simply be run on a NFS backed file.
Suggested replacement command sequence on the client:
dd if=/dev/zero of=/swapfile bs=1k count=1 oseek=100000
swapon /swapfile
rm -f /swapfile
For whatever value of 100000 you want.
to avoid Bad Things(TM) happening (eg: df crashing with a floating point
exception).
Submitted by: Harold Gutch <logix@foobar.franken.de>
Approved by: re (scottl)
machines where the 'long' number of blocks in struct statfs wont fit.
Instead of chosing an artificial 512 byte block size, simply scale it up
until we avoid an overflow. NFSv3 reports the sizes in bytes, and the
blocksize is a figment of nfsclient's imagination.
to mount_nfs. The sysctl defaults to 1 (paranoid mode). Setting it to 0
will allow an NFS client to receive replies on a different IP then they
were sent to by default.
Submitted by: Sean Eric Fagan <sef@kithrup.com>
from DHCP in the event that no gateway is returned from DHCP, breaking
the assumption that we skip the routing insertion of the gateway
if the sin length is zero. Check also for s_addr of 0 to avoid the
"Oh no, adding my default route failed" panic, making it possible
to pxeboot machines on segments without default routes. Arguably
this could be a bug in pxeboot, or in the TUNABLE code, but this
makes my boxes boot.
so that it is MI. Allow nfs_mountroot to return an error if the nfs_diskless
struct is not valid, rather than panicing later on. Call nfs_setup_diskless()
from nfs_mountroot if NFS_ROOT is defined, like bootpc_init(). Removed legacy
root mount support for sparc64, and enabled NFS_ROOT by default.
these in the main filesystems. This does not change the resulting code
but makes the source a little bit more grepable.
Sponsored by: DARPA and NAI Labs.
- v_vflag is protected by the vnode lock and is used when synchronization
with VOP calls is needed.
- v_iflag is protected by interlock and is used for dealing with vnode
management issues. These flags include X/O LOCK, FREE, DOOMED, etc.
- All accesses to v_iflag and v_vflag have either been locked or marked with
mp_fixme's.
- Many ASSERT_VOP_LOCKED calls have been added where the locking was not
clear.
- Many functions in vfs_subr.c were restructured to provide for stronger
locking.
Idea stolen from: BSD/OS
down, even if there are hung processes and the mount is non-
interruptible.
This works by having nfs_unmount call a new function nfs_nmcancelreqs()
in the FORCECLOSE case. It scans the list of outstanding requests
and marks as interrupted any requests belonging to the specified
mount. Then it waits up to 30 seconds for all requests to terminate.
A few other changes are necessary to support this:
- Unconditionally set a socket timeout so that even hard mounts
are guaranteed to occasionally check the R_SOFTTERM flag on
requests. For hard mounts this flag can only be set by
nfs_nmcancelreqs().
- Reject requests on a mount that is currently being unmounted.
- Never grant the receive lock to a request that has been cancelled.
This should also avoid an old problem where a forced NFS unmount
could cause a crash; it occurred when a VOP on an unlocked vnode
(usually VOP_GETATTR) was in progress at the time of the forced
unmount.
