For high-availability NFS service, we generally need to be able to drop
file locks held on the exported filesystem before moving clients to a
new server.  Currently the only way to do that is by shutting down lockd
entirely, which is often undesireable (for example, if you want to
continue exporting other filesystems).

This patch allows the administrator to release all locks held by clients
accessing the client through a given server ip address, by echoing that
address to a new file, /proc/fs/nfsd/unlock_ip, as in:

shell> echo 10.1.1.2 > /proc/fs/nfsd/unlock_ip

The expected sequence of events can be:
1. Tear down the IP address
2. Unexport the path
3. Write IP to /proc/fs/nfsd/unlock_ip to unlock files
4. Signal peer to begin take-over.

For now we only support IPv4 addresses and NFSv2/v3 (NFSv4 locks are not
affected).

Also, if unmounting the filesystem is required, we assume at step 3 that
clients using the given server ip are the only clients holding locks on
the given filesystem; otherwise, an additional patch is required to
allow revoking all locks held by lockd on a given filesystem.
Signed-off-by: NS. Wendy Cheng <wcheng@redhat.com>
Cc: Lon Hohberger  <lhh@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

 fs/lockd/svcsubs.c          |   66 +++++++++++++++++++++++++++++++++++++++-----
 fs/nfsd/nfsctl.c            |   65 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/lockd/lockd.h |    7 ++++
 3 files changed, 131 insertions(+), 7 deletions(-)

fcntl_setlease() has a struct dentry* that is used only once; this patch
removes it.
Signed-off-by: NDavid M. Richter <richterd@citi.umich.edu>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

In generic_setlease(), the struct file_lock is allocated after tests for the
presence of conflicting readers/writers is done, despite the fact that the
allocation might block; this patch moves the allocation earlier.  A subsequent
set of patches will rely on this behavior to properly serialize between a
modified __break_lease() and generic_setlease().
Signed-off-by: NDavid M. Richter <richterd@citi.umich.edu>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

In generic_setlease(), we don't need to allocate a new struct file_lock
or check for readers or writers when called with F_UNLCK.
Signed-off-by: NDavid M. Richter <richterd@citi.umich.edu>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Fixes a return-value mixup from 85c59580
"locks: Fix potential OOPS in generic_setlease()", in which -ENOMEM replaced
what had been intended to stay -EAGAIN in the variable "error".
Signed-off-by: NDavid M. Richter <richterd@citi.umich.edu>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: NSteve French <sfrench@us.ibm.com>

The transport encryption capability and new SetFSInfo level were missing, and the
new proxy capability (which Samba server is implementing) and proxy setfsinfo needed
to be moved down to not collide with Samba's transport encryption capability.

CC: Jeremy Allison <jra@samba.org>
CC: Sam Liddicott <sam@lidicott.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Currently, knfsd only clears the setuid bit if the owner of a file is
changed on a SETATTR call, and only clears the setgid bit if the group
is changed. POSIX says this in the spec for chown():

    "If the specified file is a regular file, one or more of the
     S_IXUSR, S_IXGRP, or S_IXOTH bits of the file mode are set, and the
     process does not have appropriate privileges, the set-user-ID
     (S_ISUID) and set-group-ID (S_ISGID) bits of the file mode shall
     be cleared upon successful return from chown()."

If I'm reading this correctly, then knfsd is doing this wrong. It should
be clearing both the setuid and setgid bit on any SETATTR that changes
the uid or gid. This wasn't really as noticable before, but now that the
ATTR_KILL_S*ID bits are a no-op for the NFS client, it's more evident.

This patch corrects the nfsd_setattr logic so that this occurs. It also
does a bit of cleanup to the function.

There is also one small behavioral change. If a SETATTR call comes in
that changes the uid/gid and the mode, then we now only clear the setgid
bit if the group execute bit isn't set. The setgid bit without a group
execute bit signifies mandatory locking and we likely don't want to
clear the bit in that case. Since there is no call in POSIX that should
generate a SETATTR call like this, then this should rarely happen, but
it's worth noting.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

...it's not really needed.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

When svc_recv returns an unexpected error, lockd will print a warning
and exit. This problematic for several reasons. In particular, it will
cause the reference counts for the thread to be wrong, and can lead to a
potential BUG() call.

Rather than exiting on error from svc_recv, have the thread do a 1s
sleep and then retry the loop. This is unlikely to cause any harm, and
if the error turns out to be something temporary then it may be able to
recover.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

When svc_recv returns an unexpected error, nfs_callback_svc will print a
warning and exit. This problematic for several reasons. In particular,
it will cause the reference counts for the thread to be wrong, and no
new thread will be started until all nfs4 mounts are unmounted.

Rather than exiting on error from svc_recv, have the thread do a 1s
sleep and then retry the loop. This is unlikely to cause any harm, and
if the error turns out to be something temporary then it may be able to
recover.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

There's no need to dynamically allocate this memory, and doing so may
create the possibility of races on shutdown of the rpc client.  (We've
witnessed it only after adding rpcsec_gss support to the server, after
which the rpc code can send destroys calls that expect to still be able
to access the rpc_stats structure after it has been destroyed.)

Such races are in theory possible if the module containing this "static"
memory is removed very quickly after an rpc client is destroyed, but
we haven't seen that happen.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Obvious comment nit.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

As of 5996a298 ("NLM: don't unlock on
cancel requests") we no longer unlock in this case, so the comment is no
longer accurate.

Thanks to Stuart Friedberg for pointing out the inconsistency.

Cc: Stuart Friedberg <sfriedberg@hp.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Clean up: Because NFSD_V4 "depends on" NFSD_V3, it appears as a child of
the NFSD_V3 menu entry, and is not visible if NFSD_V3 is unselected.

Replace the dependency on NFSD_V3 with a "select NFSD_V3".  This makes
NFSD_V4 look and work just like NFS_V3, while ensuring that NFSD_V3 is
enabled if NFSD_V4 is.

Sam Ravnborg adds:

"This use of select is questionable. In general it is bad to select
a symbol with dependencies.

In this case the dependencies of NFSD_V3 are duplicated for NFSD_V4
so we will not se erratic configurations but do you remember to
update NFSD_V4 when you add a depends on NFSD_V3?

But I see no other clean way to do it right now."

Later he said:

"My comment was more to say we have things to address in kconfig.
This is abuse in the acceptable range."
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Recently, commit 440bcc59 added a reverse dependency to fs/Kconfig to
ensure that PROC_FS was enabled if SUNRPC_GSS was enabled.

Apparently this isn't necessary because the auth_gss components under
net/sunrpc will build correctly even if PROC_FS is disabled, though
RPCSEC_GSS will not work without /proc.

It also violates the guideline in Documentation/kbuild/kconfig-language.txt
that states "In general use select only for non-visible symbols (no prompts
anywhere) and for symbols with no dependencies."

To address these issues, remove the dependency.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Recently, commit 440bcc59 added a reverse dependency to fs/Kconfig to
ensure that PROC_FS was enabled if NFSD_V4 was enabled.

There is a guideline in Documentation/kbuild/kconfig-language.txt that
states "In general use select only for non-visible symbols (no prompts
anywhere) and for symbols with no dependencies."

A quick grep around other Kconfig files reveals that no entry currently
uses "select PROC_FS" -- every one uses "depends on".  Thus CONFIG_NFSD_V4
should use "depends on PROC_FS" as well.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Move the code that actually parses the filehandle and looks up the
dentry and export to a separate function.  This simplifies the reference
counting a little and moves fh_verify() a little closer to the kernel
ideal of small, minimally-indentended functions.  Clean up a few other
minor style sins along the way.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Cc: Neil Brown <neilb@suse.de>

While lease is correctly checked by supplying the type argument to
vfs_setlease(), it's stored with fl_type uninitialized. This breaks the
logic when checking the type of the lease.  The fix is to initialize
fl_type.

The old code still happened to function correctly since F_RDLCK is zero,
and we only implement read delegations currently (nor write
delegations).  But that's no excuse for not fixing this.
Signed-off-by: NFelix Blyakher <felixb@sgi.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

There's a general push to convert kernel threads to use the (much
cleaner) kthread API. This patch converts the NFSv4 callback kernel
thread to the kthread API. In addition to being generally cleaner this
also removes the dependency on signals when shutting down the thread.

Note that this patch depends on the recent patches to svc_recv() to
make it check kthread_should_stop() periodically. Those patches are
in Bruce's tree at the moment and are slated for 2.6.26 along with
the lockd conversion, so this conversion is probably also appropriate
for 2.6.26.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Acked-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

fs/nfsd/vfs.c:991:27: warning: Using plain integer as NULL pointer
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Add extern to nfsd/nfsd.h
fs/nfsd/nfssvc.c:146:5: warning: symbol 'nfsd_nrthreads' was not declared. Should it be static?
fs/nfsd/nfssvc.c:261:5: warning: symbol 'nfsd_nrpools' was not declared. Should it be static?
fs/nfsd/nfssvc.c:269:5: warning: symbol 'nfsd_get_nrthreads' was not declared. Should it be static?
fs/nfsd/nfssvc.c:281:5: warning: symbol 'nfsd_set_nrthreads' was not declared. Should it be static?
fs/nfsd/export.c:1534:23: warning: symbol 'nfs_exports_op' was not declared. Should it be static?

Add include of auth.h
fs/nfsd/auth.c:27:5: warning: symbol 'nfsd_setuser' was not declared. Should it be static?

Make static, move forward declaration closer to where it's needed.
fs/nfsd/nfs4state.c:1877:1: warning: symbol 'laundromat_main' was not declared. Should it be static?

Make static, forward declaration was already marked static.
fs/nfsd/nfs4idmap.c:206:1: warning: symbol 'idtoname_parse' was not declared. Should it be static?
fs/nfsd/vfs.c:1156:1: warning: symbol 'nfsd_create_setattr' was not declared. Should it be static?
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

There's no reason for a mutex here, except to allow an allocation under
the lock, which we can avoid with the usual trick of preallocating
memory for the new object and freeing it if it turns out to be
unnecessary.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Use list_for_each_entry().  Also, in keeping with kernel style, make the
normal case (kzalloc succeeds) unindented and handle the abnormal case
with a goto.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The sm_count is decremented to zero but left on the nsm_handles list.
So in the space between decrementing sm_count and acquiring nsm_mutex,
it is possible for another task to find this nsm_handle, increment the
use count and then enter nsm_release itself.

Thus there's nothing to prevent the nsm being freed before we acquire
nsm_mutex here.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

fs/lockd/svcshare.c:74:50: warning: Using plain integer as NULL pointer
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

This patch makes the needlessly global nfsd_create_setattr() static.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

As far as I can tell, selecting the CRYPTO and CRYPTO_MD5 entries under
CONFIG_NFSD is redundant, since CONFIG_NFSD_V4 already selects
RPCSEC_GSS_KRB5, which selects these entries.

Testing with "make menuconfig" shows that the entries under CRYPTO still
properly reflect "Y" or "M" based on the setting of CONFIG_NFSD after this
change is applied.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Clean up: since NFSD_V2_ACL is a boolean, it can be selected safely
under the NFSD_V3_ACL entry (also a boolean).
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Clean up: since FS_POSIX_ACL is a non-visible boolean entry, it can be
selected safely under the NFSD_V4 entry (also a boolean).
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Clean up: refresh the help text for Kconfig items related to the NFS
server.  Remove obsolete URLs, and make the language consistent among
the options.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Likewise, distros usually leave CONFIG_NFSD_TCP enabled.

TCP support in the Linux NFS server is stable enough that we can leave it
on always.  CONFIG_NFSD_TCP adds about 10 lines of code, and defaults to
"Y" anyway.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The code here is difficult to understand; attempt to clarify somewhat by
pulling out one of the more mystifying conditionals into a separate
function.

While we're here, also add lease_time to the list of attributes that we
don't really need to cross a mountpoint to fetch.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Cc: Peter Staubach <staubach@redhat.com>

This condition is always true.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Pull this common code into a separate function.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Every caller sets this flag, so it's meaningless.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Thanks to Robert Day for pointing out that these two defines are unused.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Cc: Trond Myklebust <trond@netapp.com>Trond Myklebust <trond@netapp.com>
Cc: Neil Brown <neilb@suse.de>
Cc: "Robert P. J. Day" <rpjday@crashcourse.ca>

This adds IPv6 support to the interfaces that are used to express nfsd
exports.  All addressed are stored internally as IPv6; backwards
compatibility is maintained using mapped addresses.

Thanks to Bruce Fields, Brian Haley, Neil Brown and Hideaki Joshifuji
for comments
Signed-off-by: NAurelien Charbon <aurelien.charbon@bull.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Brian Haley <brian.haley@hp.com>
Cc:  YOSHIFUJI Hideaki / 吉藤英明 <yoshfuji@linux-ipv6.org>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Have lockd_up start lockd using kthread_run. With this change,
lockd_down now blocks until lockd actually exits, so there's no longer
need for the waitqueue code at the end of lockd_down. This also means
that only one lockd can be running at a time which simplifies the code
within lockd's main loop.

This also adds a check for kthread_should_stop in the main loop of
nlmsvc_retry_blocked and after that function returns. There's no sense
continuing to retry blocks if lockd is coming down anyway.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Lockd caches information about hosts that have recently held locks to
expedite the taking of further locks.

It periodically discards this information for hosts that have not been
used for a few minutes.

lockd currently has a value NLM_HOST_MAX, and changes the 'garbage
collection' behaviour when the number of hosts exceeds this threshold.

However its behaviour is strange, and likely not what was intended.
When the number of hosts exceeds the max, it scans *less* often (every
2 minutes vs every minute) and allows unused host information to
remain around longer (5 minutes instead of 2).

Having this limit is of dubious value anyway, and we have not
suffered from the code not getting the limit right, so remove the
limit altogether.  We go with the larger values (discard 5 minute old
hosts every 2 minutes) as they are probably safer.

Maybe the periodic garbage collection should be replace to with
'shrinker' handler so we just respond to memory pressure....
Acked-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>