Commit df52699e4f ("NFSv4.1: Don't cache deviceids that have no
notifications") causes the Linux NFS client to stop caching deviceid's
unless a server pretends to support deviceid notifications. While this
behavior is stupid and the language around this area in rfc5661 is a
mess carified by an errata that I submittted, Trond insists on this
behavior. Not caching deviceids degrades block layout performance
massively as a GETDEVICEINFO is fairly expensive.
So add this hack to make the Linux client happy again.
Cc: stable@vger.kernel.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Pull fourth vfs update from Al Viro:
"d_inode() annotations from David Howells (sat in for-next since before
the beginning of merge window) + four assorted fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
RCU pathwalk breakage when running into a symlink overmounting something
fix I_DIO_WAKEUP definition
direct-io: only inc/dec inode->i_dio_count for file systems
fs/9p: fix readdir()
VFS: assorted d_backing_inode() annotations
VFS: fs/inode.c helpers: d_inode() annotations
VFS: fs/cachefiles: d_backing_inode() annotations
VFS: fs library helpers: d_inode() annotations
VFS: assorted weird filesystems: d_inode() annotations
VFS: normal filesystems (and lustre): d_inode() annotations
VFS: security/: d_inode() annotations
VFS: security/: d_backing_inode() annotations
VFS: net/: d_inode() annotations
VFS: net/unix: d_backing_inode() annotations
VFS: kernel/: d_inode() annotations
VFS: audit: d_backing_inode() annotations
VFS: Fix up some ->d_inode accesses in the chelsio driver
VFS: Cachefiles should perform fs modifications on the top layer only
VFS: AF_UNIX sockets should call mknod on the top layer only
Pull nfsd updates from Bruce Fields:
"A quiet cycle this time; this is basically entirely bugfixes.
The few that aren't cc'd to stable are cleanup or seemed unlikely to
affect anyone much"
* 'for-4.1' of git://linux-nfs.org/~bfields/linux:
uapi: Remove kernel internal declaration
nfsd: fix nsfd startup race triggering BUG_ON
nfsd: eliminate NFSD_DEBUG
nfsd4: fix READ permission checking
nfsd4: disallow SEEK with special stateids
nfsd4: disallow ALLOCATE with special stateids
nfsd: add NFSEXP_PNFS to the exflags array
nfsd: Remove duplicate macro define for max sec label length
nfsd: allow setting acls with unenforceable DENYs
nfsd: NFSD_FAULT_INJECTION depends on DEBUG_FS
nfsd: remove unused status arg to nfsd4_cleanup_open_state
nfsd: remove bogus setting of status in nfsd4_process_open2
NFSD: Use correct reply size calculating function
NFSD: Using path_equal() for checking two paths
nfsd triggered a BUG_ON in net_generic(...) when rpc_pipefs_event(...)
in fs/nfsd/nfs4recover.c was called before assigning ntfsd_net_id.
The following was observed on a MIPS 32-core processor:
kernel: Call Trace:
kernel: [<ffffffffc00bc5e4>] rpc_pipefs_event+0x7c/0x158 [nfsd]
kernel: [<ffffffff8017a2a0>] notifier_call_chain+0x70/0xb8
kernel: [<ffffffff8017a4e4>] __blocking_notifier_call_chain+0x4c/0x70
kernel: [<ffffffff8053aff8>] rpc_fill_super+0xf8/0x1a0
kernel: [<ffffffff8022204c>] mount_ns+0xb4/0xf0
kernel: [<ffffffff80222b48>] mount_fs+0x50/0x1f8
kernel: [<ffffffff8023dc00>] vfs_kern_mount+0x58/0xf0
kernel: [<ffffffff802404ac>] do_mount+0x27c/0xa28
kernel: [<ffffffff80240cf0>] SyS_mount+0x98/0xe8
kernel: [<ffffffff80135d24>] handle_sys64+0x44/0x68
kernel:
kernel:
Code: 0040f809 00000000 2e020001 <00020336> 3c12c00d
3c02801a de100000 6442eb98 0040f809
kernel: ---[ end trace 7471374335809536 ]---
Fixed this behaviour by calling register_pernet_subsys(&nfsd_net_ops) before
registering rpc_pipefs_event(...) with the notifier chain.
Signed-off-by: Giuseppe Cantavenera <giuseppe.cantavenera.ext@nokia.com>
Signed-off-by: Lorenzo Restelli <lorenzo.restelli.ext@nokia.com>
Reviewed-by: Kinlong Mee <kinglongmee@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Commit f895b252d4 ("sunrpc: eliminate RPC_DEBUG") introduced
use of IS_ENABLED() in a uapi header which leads to a build
failure for userspace apps trying to use <linux/nfsd/debug.h>:
linux/nfsd/debug.h:18:15: error: missing binary operator before token "("
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
^
Since this was only used to define NFSD_DEBUG if CONFIG_SUNRPC_DEBUG
is enabled, replace instances of NFSD_DEBUG with CONFIG_SUNRPC_DEBUG.
Cc: stable@vger.kernel.org
Fixes: f895b252d4 "sunrpc: eliminate RPC_DEBUG"
Signed-off-by: Mark Salter <msalter@redhat.com>
Reviewed-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
In the case we already have a struct file (derived from a stateid), we
still need to do permission-checking; otherwise an unauthorized user
could gain access to a file by sniffing or guessing somebody else's
stateid.
Cc: stable@vger.kernel.org
Fixes: dc97618ddd "nfsd4: separate splice and readv cases"
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
If the client uses a special stateid then we'll pass a NULL file to
vfs_llseek.
Fixes: 24bab49122 " NFSD: Implement SEEK"
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: stable@vger.kernel.org
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
vfs_fallocate will hit a NULL dereference if the client tries an
ALLOCATE or DEALLOCATE with a special stateid. Fix that. (We also
depend on the open to have broken any conflicting leases or delegations
for us.)
(If it turns out we need to allow special stateid's then we could do a
temporary open here in the special-stateid case, as we do for read and
write. For now I'm assuming it's not necessary.)
Fixes: 95d871f03c "nfsd: Add ALLOCATE support"
Cc: stable@vger.kernel.org
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Merge second patchbomb from Andrew Morton:
- the rest of MM
- various misc bits
- add ability to run /sbin/reboot at reboot time
- printk/vsprintf changes
- fiddle with seq_printf() return value
* akpm: (114 commits)
parisc: remove use of seq_printf return value
lru_cache: remove use of seq_printf return value
tracing: remove use of seq_printf return value
cgroup: remove use of seq_printf return value
proc: remove use of seq_printf return value
s390: remove use of seq_printf return value
cris fasttimer: remove use of seq_printf return value
cris: remove use of seq_printf return value
openrisc: remove use of seq_printf return value
ARM: plat-pxa: remove use of seq_printf return value
nios2: cpuinfo: remove use of seq_printf return value
microblaze: mb: remove use of seq_printf return value
ipc: remove use of seq_printf return value
rtc: remove use of seq_printf return value
power: wakeup: remove use of seq_printf return value
x86: mtrr: if: remove use of seq_printf return value
linux/bitmap.h: improve BITMAP_{LAST,FIRST}_WORD_MASK
MAINTAINERS: CREDITS: remove Stefano Brivio from B43
.mailmap: add Ricardo Ribalda
CREDITS: add Ricardo Ribalda Delgado
...
There are a lot of embedded systems that run most or all of their
functionality in init, running as root:root. For these systems,
supporting multiple users is not necessary.
This patch adds a new symbol, CONFIG_MULTIUSER, that makes support for
non-root users, non-root groups, and capabilities optional. It is enabled
under CONFIG_EXPERT menu.
When this symbol is not defined, UID and GID are zero in any possible case
and processes always have all capabilities.
The following syscalls are compiled out: setuid, setregid, setgid,
setreuid, setresuid, getresuid, setresgid, getresgid, setgroups,
getgroups, setfsuid, setfsgid, capget, capset.
Also, groups.c is compiled out completely.
In kernel/capability.c, capable function was moved in order to avoid
adding two ifdef blocks.
This change saves about 25 KB on a defconfig build. The most minimal
kernels have total text sizes in the high hundreds of kB rather than
low MB. (The 25k goes down a bit with allnoconfig, but not that much.
The kernel was booted in Qemu. All the common functionalities work.
Adding users/groups is not possible, failing with -ENOSYS.
Bloat-o-meter output:
add/remove: 7/87 grow/shrink: 19/397 up/down: 1675/-26325 (-24650)
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Iulia Manda <iulia.manda21@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
that's the bulk of filesystem drivers dealing with inodes of their own
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The current prototypes for these operations are somewhat awkward as they
deal with fl_owners but take struct file_lock arguments. In the future,
we'll want to be able to take references without necessarily dealing
with a struct file_lock.
Change them to take fl_owner_t arguments instead and have the callers
deal with assigning the values to the file_lock structs.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
NFS4_MAXLABELLEN has defined for sec label max length, use it directly.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
We've been refusing ACLs that DENY permissions that we can't effectively
deny. (For example, we can't deny permission to read attributes.)
Andreas points out that any DENY of Window's "read", "write", or
"modify" permissions would trigger this. That would be annoying.
So maybe we should be a little less paranoid, and ignore entirely the
permissions that are meaningless to us.
Reported-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
NFSD_FAULT_INJECTION depends on DEBUG_FS, otherwise the debugfs_create_*
interface may return unexpected error -ENODEV, and cause system crash.
Signed-off-by: Chengyu Song <csong84@gatech.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
status is always reset after this (and it doesn't make much sense there
anyway).
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
ALLOCATE/DEALLOCATE only reply one status value to client,
so, using nfsd4_only_status_rsize for reply size calculating.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Reviewed-by: Anna Schumaker <Anna.Schumaker@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Turns out sending out layouts to any client is a bad idea if they
can't get at the storage device, so require explicit admin action
to enable pNFS.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
With return layout as, (seg is return layout, lo is record layout)
seg->offset <= lo->offset and layout_end(seg) < layout_end(lo),
nfsd should update lo's offset to seg's end,
and,
seg->offset > lo->offset and layout_end(seg) >= layout_end(lo),
nfsd should update lo's end to seg's offset.
Fixes: 9cf514ccfa ("nfsd: implement pNFS operations")
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
When testing pnfs with nfsd_debug on, nfsd print a negative number
of layout length and foff in nfsd4_block_proc_layoutget as,
"GET: -xxxx:-xxx 2"
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
alloc_init_lock_stateowner can return an already freed entry if there is
a race to put openowners in the hashtable.
Noticed by inspection after Jeff Layton fixed the same bug for open
owners. Depending on client behavior, this one may be trickier to
trigger in practice.
Fixes: c58c6610ec "nfsd: Protect adding/removing lock owners using client_lock"
Cc: <stable@vger.kernel.org>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Acked-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
alloc_init_open_stateowner can return an already freed entry if there is
a race to put openowners in the hashtable.
In commit 7ffb588086, we changed it so that we allocate and initialize
an openowner, and then check to see if a matching one got stuffed into
the hashtable in the meantime. If it did, then we free the one we just
allocated and take a reference on the one already there. There is a bug
here though. The code will then return the pointer to the one that was
allocated (and has now been freed).
This wasn't evident before as this race almost never occurred. The Linux
kernel client used to serialize requests for a single openowner. That
has changed now with v4.0 kernels, and this race can now easily occur.
Fixes: 7ffb588086
Cc: <stable@vger.kernel.org> # v3.17+
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Reported-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Fix commit 9cf514ccfa (nfsd: implement pNFS operations).
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Return status after nfsd4_decode_stateid failed.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
According to RFC5661:
" When lr_returntype is LAYOUTRETURN4_FSID, the current filehandle is used
to identify the file system and all layouts matching the client ID,
the fsid of the file system, lora_layout_type, and lora_iomode are
returned. When lr_returntype is LAYOUTRETURN4_ALL, all layouts
matching the client ID, lora_layout_type, and lora_iomode are
returned and the current filehandle is not used. "
When returning client layouts, always check layout type.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
31ef83dc05 "nfsd: add trace events" had a typo that dropped a trace
event and replaced it by an incorrect recursive call to
nfsd4_cb_layout_fail. 133d558216 "Subject: nfsd: don't recursively
call nfsd4_cb_layout_fail" fixed the crash, this restores the
tracepoint.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Pull nfsd fixes from Bruce Fields:
"Three miscellaneous bugfixes, most importantly the clp->cl_revoked
bug, which we've seen several reports of people hitting"
* 'for-4.0' of git://linux-nfs.org/~bfields/linux:
sunrpc: integer underflow in rsc_parse()
nfsd: fix clp->cl_revoked list deletion causing softlock in nfsd
svcrpc: fix memory leak in gssp_accept_sec_context_upcall
commit 2d4a532d38 ("nfsd: ensure that clp->cl_revoked list is
protected by clp->cl_lock") removed the use of the reaplist to
clean out clp->cl_revoked. It failed to change list_entry() to
walk clp->cl_revoked.next instead of reaplist.next
Fixes: 2d4a532d38 ("nfsd: ensure that clp->cl_revoked list is protected by clp->cl_lock")
Cc: stable@vger.kernel.org
Reported-by: Eric Meddaugh <etmsys@rit.edu>
Tested-by: Eric Meddaugh <etmsys@rit.edu>
Signed-off-by: Andrew Elble <aweits@rit.edu>
Reviewed-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Convert the following where appropriate:
(1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry).
(2) S_ISREG(dentry->d_inode) to d_is_reg(dentry).
(3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more
complicated than it appears as some calls should be converted to
d_can_lookup() instead. The difference is whether the directory in
question is a real dir with a ->lookup op or whether it's a fake dir with
a ->d_automount op.
In some circumstances, we can subsume checks for dentry->d_inode not being
NULL into this, provided we the code isn't in a filesystem that expects
d_inode to be NULL if the dirent really *is* negative (ie. if we're going to
use d_inode() rather than d_backing_inode() to get the inode pointer).
Note that the dentry type field may be set to something other than
DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS
manages the fall-through from a negative dentry to a lower layer. In such a
case, the dentry type of the negative union dentry is set to the same as the
type of the lower dentry.
However, if you know d_inode is not NULL at the call site, then you can use
the d_is_xxx() functions even in a filesystem.
There is one further complication: a 0,0 chardev dentry may be labelled
DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was
intended for special directory entry types that don't have attached inodes.
The following perl+coccinelle script was used:
use strict;
my @callers;
open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') ||
die "Can't grep for S_ISDIR and co. callers";
@callers = <$fd>;
close($fd);
unless (@callers) {
print "No matches\n";
exit(0);
}
my @cocci = (
'@@',
'expression E;',
'@@',
'',
'- S_ISLNK(E->d_inode->i_mode)',
'+ d_is_symlink(E)',
'',
'@@',
'expression E;',
'@@',
'',
'- S_ISDIR(E->d_inode->i_mode)',
'+ d_is_dir(E)',
'',
'@@',
'expression E;',
'@@',
'',
'- S_ISREG(E->d_inode->i_mode)',
'+ d_is_reg(E)' );
my $coccifile = "tmp.sp.cocci";
open($fd, ">$coccifile") || die $coccifile;
print($fd "$_\n") || die $coccifile foreach (@cocci);
close($fd);
foreach my $file (@callers) {
chomp $file;
print "Processing ", $file, "\n";
system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 ||
die "spatch failed";
}
[AV: overlayfs parts skipped]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Includes of pnfs.h in export.c and fcntl.c also bring in xdr4.h, which
won't build without CONFIG_NFSD_V3, breaking non-V3 builds. Ifdef-out
most of pnfs.h in that case.
Reported-by: Bas Peters <baspeters93@gmail.com>
Reported-by: Jim Davis <jim.epost@gmail.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Fixes: 9cf514ccfa "nfsd: implement pNFS operations"
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
We're supposed to be testing that the fh_fsid's match but because the
parenthesis are in the wrong place, then we only check the first
byte.
Fixes: 9558f2500a ('nfsd: add fh_fsid_match helper')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The code seems to work. The protocol looks stable. The kernel's
version defaults can be overridden by rpc.nfsd arguments.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Add a small shim between core nfsd and filesystems to translate the
somewhat cumbersome pNFS data structures and semantics to something
more palatable for Linux filesystems.
Thanks to Rick McNeal for the old prototype pNFS blocklayout server
code, which gave a lot of inspiration to this version even if no
code is left from it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
For now just a few simple events to trace the layout stateid lifetime, but
these already were enough to find several bugs in the Linux client layout
stateid handling.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add support to issue layout recalls to clients. For now we only support
full-file recalls to get a simple and stable implementation. This allows
to embedd a nfsd4_callback structure in the layout_state and thus avoid
any memory allocations under spinlocks during a recall. For normal
use cases that do not intent to share a single file between multiple
clients this implementation is fully sufficient.
To ensure layouts are recalled on local filesystem access each layout
state registers a new FL_LAYOUT lease with the kernel file locking code,
which filesystems that support pNFS exports that require recalls need
to break on conflicting access patterns.
The XDR code is based on the old pNFS server implementation by
Andy Adamson, Benny Halevy, Boaz Harrosh, Dean Hildebrand, Fred Isaman,
Marc Eshel, Mike Sager and Ricardo Labiaga.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add support for the GETDEVICEINFO, LAYOUTGET, LAYOUTCOMMIT and
LAYOUTRETURN NFSv4.1 operations, as well as backing code to manage
outstanding layouts and devices.
Layout management is very straight forward, with a nfs4_layout_stateid
structure that extends nfs4_stid to manage layout stateids as the
top-level structure. It is linked into the nfs4_file and nfs4_client
structures like the other stateids, and contains a linked list of
layouts that hang of the stateid. The actual layout operations are
implemented in layout drivers that are not part of this commit, but
will be added later.
The worst part of this commit is the management of the pNFS device IDs,
which suffers from a specification that is not sanely implementable due
to the fact that the device-IDs are global and not bound to an export,
and have a small enough size so that we can't store the fsid portion of
a file handle, and must never be reused. As we still do need perform all
export authentication and validation checks on a device ID passed to
GETDEVICEINFO we are caught between a rock and a hard place. To work
around this issue we add a new hash that maps from a 64-bit integer to a
fsid so that we can look up the export to authenticate against it,
a 32-bit integer as a generation that we can bump when changing the device,
and a currently unused 32-bit integer that could be used in the future
to handle more than a single device per export. Entries in this hash
table are never deleted as we can't reuse the ids anyway, and would have
a severe lifetime problem anyway as Linux export structures are temporary
structures that can go away under load.
Parts of the XDR data, structures and marshaling/unmarshaling code, as
well as many concepts are derived from the old pNFS server implementation
from Andy Adamson, Benny Halevy, Dean Hildebrand, Marc Eshel, Fred Isaman,
Mike Sager, Ricardo Labiaga and many others.
Signed-off-by: Christoph Hellwig <hch@lst.de>
The pnfs code will need it too. Also remove the nfsd_ prefix to match the
other filehandle helpers in that file.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Just like for other lock types we should allow different owners to have
a read lease on a file. Currently this can't happen, but with the addition
of pNFS layout leases we'll need this feature.
Signed-off-by: Christoph Hellwig <hch@lst.de>
