We may get a notification and lose the race to another client. Ensure
that we wait again for a notification in that case.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

The structure nlmclnt_fl_close_lock_ops s local to the source and does
not need to be in global scope, so make it static.

Cleans up sparse warning:
fs/nfs/nfs3proc.c:876:33: warning: symbol 'nlmclnt_fl_close_lock_ops' was not
declared. Should it be static?
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

nfs4_update_server unconditionally releases the nfs_client for the
source server. If migration fails, this can cause the source server's
nfs_client struct to be left with a low reference count, resulting in
use-after-free.  Also, adjust reference count handling for ELOOP.

NFS: state manager: migration failed on NFSv4 server nfsvmu10 with error 6
WARNING: CPU: 16 PID: 17960 at fs/nfs/client.c:281 nfs_put_client+0xfa/0x110 [nfs]()
	nfs_put_client+0xfa/0x110 [nfs]
	nfs4_run_state_manager+0x30/0x40 [nfsv4]
	kthread+0xd8/0xf0

BUG: unable to handle kernel NULL pointer dereference at 00000000000002a8
	nfs4_xdr_enc_write+0x6b/0x160 [nfsv4]
	rpcauth_wrap_req+0xac/0xf0 [sunrpc]
	call_transmit+0x18c/0x2c0 [sunrpc]
	__rpc_execute+0xa6/0x490 [sunrpc]
	rpc_async_schedule+0x15/0x20 [sunrpc]
	process_one_work+0x160/0x470
	worker_thread+0x112/0x540
	? rescuer_thread+0x3f0/0x3f0
	kthread+0xd8/0xf0

This bug was introduced by 32e62b7c ("NFS: Add nfs4_update_server"),
but the fix applies cleanly to 52442f9b ("NFS4: Avoid migration loops")
Reported-by: NHelen Chao <helen.chao@oracle.com>
Fixes: 52442f9b ("NFS4: Avoid migration loops")
Signed-off-by: NBill Baker <bill.baker@oracle.com>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Passing a pointer to a unsigned integer to test_bit() is broken.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The function inode_cmp_iversion{+raw} is counter-intuitive, because it
returns true when the counters are different and false when these are equal.

Rename it to inode_eq_iversion{+raw}, which will returns true when
the counters are equal and false otherwise.
Signed-off-by: NGoffredo Baroncelli <kreijack@inwind.it>
Signed-off-by: NJeff Layton <jlayton@redhat.com>

For NFS, we just use the "raw" API since the i_version is mostly
managed by the server. The exception there is when the client
holds a write delegation, but we only need to bump it once
there anyway to handle CB_GETATTR.
Tested-by: NKrzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: NJeff Layton <jlayton@redhat.com>

When locking the file in order to do O_DIRECT on it, we must unmap
any mmapped ranges on the pagecache so that we can flush out the
dirty data.

Fixes: a5864c99 ("NFS: Do not serialise O_DIRECT reads and writes")
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.8+

We don't need to call unmap_mapping_range() prior to calling
nfs_sync_mapping().
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

It's possible that the device map is smaller than the offset into the device
for the I/O we're adding.  Add a check for it and bail out, otherwise we
risk botching the bio calculations that follow.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: NTrond Myklebust <trondmy@gmail.com>

Fixup the field types to match their use.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: NTrond Myklebust <trondmy@gmail.com>

nfs_idmap_legacy_upcall() is supposed to be called with 'aux' pointing
to a 'struct idmap', via the call to request_key_with_auxdata() in
nfs_idmap_request_key().

However it can also be reached via the request_key() system call in
which case 'aux' will be NULL, causing a NULL pointer dereference in
nfs_idmap_prepare_pipe_upcall(), assuming that the key description is
valid enough to get that far.

Fix this by making nfs_idmap_legacy_upcall() negate the key if no
auxdata is provided.

As usual, this bug was found by syzkaller.  A simple reproducer using
the command-line keyctl program is:

    keyctl request2 id_legacy uid:0 '' @s

Fixes: 57e62324 ("NFS: Store the legacy idmapper result in the keyring")
Reported-by: syzbot+5dfdbcf7b3eb5912abbb@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org> # v3.4+
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NTrond Myklebust <trondmy@gmail.com>

Since commit 57e62324 ("NFS: Store the legacy idmapper result in the
keyring") nfs_idmap_cache_timeout changed units from jiffies to seconds.
Unfortunately sysctl interface was not updated accordingly.

As a effect updating /proc/sys/fs/nfs/idmap_cache_timeout with some
value will incorrectly multiply this value by HZ.
Also reading /proc/sys/fs/nfs/idmap_cache_timeout will show real value
divided by HZ.

Fixes: 57e62324 ("NFS: Store the legacy idmapper result in the keyring")
Signed-off-by: NJan Chochol <jan@chochol.info>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Commit 8224b273 ("NFS: Add static NFS I/O tracepoints") had a
hack to work around some odd behavior observed with
__print_symbolic. I couldn't ever get it to display NFS_FILE_SYNC
when using TRACE_DEFINE_ENUM macros to set up the enum values.

I tracked down the actual bug that forced me to add the workaround.
That issue will be addressed soon, so replace the hack with a proper
implementation.

Fixes: 8224b273 ("NFS: Add static NFS I/O tracepoints")
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

A pNFS server may return LAYOUTUNAVAILABLE error on LAYOUTGET for files
which don't have any layout. In this situation pnfs_update_layout
currently returns NULL. As this NULL is converted into ENOMEM, IO
requests fails instead of falling back to MDS.

Do not return ENOMEM on LAYOUTUNAVAILABLE and let client retry through
MDS.

Fixes 8d40b0f1. I will suggest to backport this fix to affected
stable branches.
Signed-off-by: NTigran Mkrtchyan <tigran.mkrtchyan@desy.de>
[trondmy: Use IS_ERR_OR_NULL()]
Fixes: 8d40b0f1 ("NFS filelayout:call GETDEVICEINFO after...")
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If some of the WRITE calls making up an O_DIRECT write syscall fail,
we neglect to commit, even if some of the WRITEs succeed.

We also depend on the commit code to free the reference count on the
nfs_page taken in the "if (request_commit)" case at the end of
nfs_direct_write_completion().  The problem was originally noticed
because ENOSPC's encountered partway through a write would result in a
closed file being sillyrenamed when it should have been unlinked.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The only reference to the label got removed, so we now get
a harmless compiler warning:

fs/nfs/export.c: In function 'nfs_encode_fh':
fs/nfs/export.c:58:1: error: label 'out' defined but not used [-Werror=unused-label]

Fixes: aaa15008 ("nfs: remove dead code from nfs_encode_fh()")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

After traversing a referral or recovering from a migration event,
ensure that the server port reported in /proc/mounts is updated
to the correct port setting for the new submount.
Reported-by: NHelen Chao <helen.chao@oracle.com>
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Helen Chao <helen.chao@oracle.com> noticed that when a user
traverses a referral on an NFS/RDMA mount, the resulting submount
always uses TCP.

This behavior does not match the vers= setting when traversing
a referral (vers=4.1 is preserved). It also does not match the
behavior of crossing from the pseudofs into a real filesystem
(proto=rdma is preserved in that case).

The Linux NFS client does not currently support the
fs_locations_info attribute. The situation is similar for all
NFSv4 servers I know of. Therefore until the community has broad
support for fs_locations_info, when following a referral:

 - First try to connect with RPC-over-RDMA. This will fail quickly
   if the client has no RDMA-capable interfaces.

 - If connecting with RPC-over-RDMA fails, or the RPC-over-RDMA
   transport is not available, use TCP.
Reported-by: NHelen Chao <helen.chao@oracle.com>
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Currently when falling back to doing I/O through the MDS (via
pnfs_{read|write}_through_mds), the client frees the nfs_pgio_header
without releasing the reference taken on the dreq
via pnfs_generic_pg_{read|write}pages -> nfs_pgheader_init ->
nfs_direct_pgio_init.  It then takes another reference on the dreq via
nfs_generic_pg_pgios -> nfs_pgheader_init -> nfs_direct_pgio_init and
as a result the requester will become stuck in inode_dio_wait.  Once
that happens, other processes accessing the inode will become stuck as
well.

Ensure that pnfs_read_through_mds() and pnfs_write_through_mds() clean
up correctly by calling hdr->completion_ops->completion() instead of
calling hdr->release() directly.

This can be reproduced (sometimes) by performing "storage failover
takeover" commands on NetApp filer while doing direct I/O from a client.

This can also be reproduced using SystemTap to simulate a failure while
doing direct I/O from a client (from Dave Wysochanski
<dwysocha@redhat.com>):

stap -v -g -e 'probe module("nfs_layout_nfsv41_files").function("nfs4_fl_prepare_ds").return { $return=NULL; exit(); }'
Suggested-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NScott Mayhew <smayhew@redhat.com>
Fixes: 1ca018d2 ("pNFS: Fix a memory leak when attempted pnfs fails")
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

PNFS block/SCSI layouts should gracefully handle cases where block devices
are not available when a layout is retrieved, or the block devices are
removed while the client holds a layout.

While setting up a layout segment, keep a record of an unavailable or
un-parsable block device in cache with a flag so that subsequent layouts do
not spam the server with GETDEVINFO.  We can reuse the current
NFS_DEVICEID_UNAVAILABLE handling with one variation: instead of reusing
the device, we will discard it and send a fresh GETDEVINFO after the
timeout, since the lookup and validation of the device occurs within the
GETDEVINFO response handling.

A lookup of a layout segment that references an unavailable device will
return a segment with the NFS_LSEG_UNAVAILABLE flag set.  This will allow
the pgio layer to mark the layout with the appropriate fail bit, which
forces subsequent IO to the MDS, and prevents spamming the server with
LAYOUTGET, LAYOUTRETURN.

Finally, when IO to a block device fails, look up the block device(s)
referenced by the pgio header, and mark them as unavailable.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If there's an error doing I/O to block device, and the client resends the
I/O to the MDS, the MDS must recall the layout from the client before
processing the I/O.  Let's preempt that exchange by returning the layout
before falling back to the MDS when there's an error.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The blocklayout module contains the client support for both block and SCSI
layouts.  Add a module alias for the SCSI layout type so that the module
will be loaded for SCSI layouts.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

nfs_pgio_rpcsetup() is always called with an offset of 0, so we should be
able to drop the arguement altogether.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

There are 2 comments in the NFSv4 code which suggest that
SIGLOST should possibly be sent to a process.  In these
cases a lock has been lost.
The current practice is to set NFS_LOCK_LOST so that
read/write returns EIO when a lock is lost.
So change these comments to code when sets NFS_LOCK_LOST.

One case is when lock recovery after apparent server restart
fails with NFS4ERR_DENIED, NFS4ERR_RECLAIM_BAD, or
NFS4ERRO_RECLAIM_CONFLICT.  The other case is when a lock
attempt as part of lease recovery fails with NFS4ERR_DENIED.

In an ideal world, these should not happen.  However I have
a packet trace showing an NFSv4.1 session getting
NFS4ERR_BADSESSION after an extended network parition.  The
NFSv4.1 client treats this like server reboot until/unless
it get NFS4ERR_NO_GRACE, in which case it switches over to
"nograce" recovery mode.  In this network trace, the client
attempts to recover a lock and the server (incorrectly)
reports NFS4ERR_DENIED rather than NFS4ERR_NO_GRACE.  This
leads to the ineffective comment and the client then
continues to write using the OPEN stateid.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This code can never be used as the IS_AUTOMOUNT(inode)
case has already been handled.
So remove it to avoid confusion.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Support the query flags AT_STATX_FORCE_SYNC by forcing an attribute
revalidation, and AT_STATX_DONT_SYNC by returning cached attributes
only.

Use the mask to optimise away server revalidation for attributes
that are not being requested by the user.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The LOOKUPP operation was inserted into the nfs4_procedures array
rather than being appended, which put /proc/net/rpc/nfs out of
whack, and broke the nfsstat utility.
Fix by moving the LOOKUPP operation to the end of the array, and
by ensuring that it keeps the same length whether or not NFSV4.1
and NFSv4.2 are compiled in.

Fixes: 5b5faaf6 ("nfs4: add NFSv4 LOOKUPP handlers")
Cc: stable@vger.kernel.org # v4.13+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Convert CLOSE so that it specifies the correct stateid and
inode for the error handling.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Convert CLOSE so that it specifies the correct stateid, state and
inode for the error handling.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The commit list can get very large, and so we need a cond_resched()
in nfs_commit_release_pages() in order to ensure we don't hog the CPU
for excessive periods of time.
Reported-by: NMike Galbraith <efault@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

should've been killed by "vfs: pull btrfs clone API to vfs layer"...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If there were no commit requests, then nfs_commit_inode() should not
wait on the commit or mark the inode dirty, otherwise the following
BUG_ON can be triggered:

[ 1917.130762] kernel BUG at fs/inode.c:578!
[ 1917.130766] Oops: Exception in kernel mode, sig: 5 [#1]
[ 1917.130768] SMP NR_CPUS=2048 NUMA pSeries
[ 1917.130772] Modules linked in: iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi blocklayoutdriver rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache sunrpc sg nx_crypto pseries_rng ip_tables xfs libcrc32c sd_mod crc_t10dif crct10dif_generic crct10dif_common ibmvscsi scsi_transport_srp ibmveth scsi_tgt dm_mirror dm_region_hash dm_log dm_mod
[ 1917.130805] CPU: 2 PID: 14923 Comm: umount.nfs4 Tainted: G               ------------ T 3.10.0-768.el7.ppc64 #1
[ 1917.130810] task: c0000005ecd88040 ti: c00000004cea0000 task.ti: c00000004cea0000
[ 1917.130813] NIP: c000000000354178 LR: c000000000354160 CTR: c00000000012db80
[ 1917.130816] REGS: c00000004cea3720 TRAP: 0700   Tainted: G               ------------ T  (3.10.0-768.el7.ppc64)
[ 1917.130820] MSR: 8000000100029032 <SF,EE,ME,IR,DR,RI>  CR: 22002822  XER: 20000000
[ 1917.130828] CFAR: c00000000011f594 SOFTE: 1
GPR00: c000000000354160 c00000004cea39a0 c0000000014c4700 c0000000018cc750
GPR04: 000000000000c750 80c0000000000000 0600000000000000 04eeb76bea749a03
GPR08: 0000000000000034 c0000000018cc758 0000000000000001 d000000005e619e8
GPR12: c00000000012db80 c000000007b31200 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR24: 0000000000000000 c000000000dfc3ec 0000000000000000 c0000005eefc02c0
GPR28: d0000000079dbd50 c0000005b94a02c0 c0000005b94a0250 c0000005b94a01c8
[ 1917.130867] NIP [c000000000354178] .evict+0x1c8/0x350
[ 1917.130871] LR [c000000000354160] .evict+0x1b0/0x350
[ 1917.130873] Call Trace:
[ 1917.130876] [c00000004cea39a0] [c000000000354160] .evict+0x1b0/0x350 (unreliable)
[ 1917.130880] [c00000004cea3a30] [c0000000003558cc] .evict_inodes+0x13c/0x270
[ 1917.130884] [c00000004cea3af0] [c000000000327d20] .kill_anon_super+0x70/0x1e0
[ 1917.130896] [c00000004cea3b80] [d000000005e43e30] .nfs_kill_super+0x20/0x60 [nfs]
[ 1917.130900] [c00000004cea3c00] [c000000000328a20] .deactivate_locked_super+0xa0/0x1b0
[ 1917.130903] [c00000004cea3c80] [c00000000035ba54] .cleanup_mnt+0xd4/0x180
[ 1917.130907] [c00000004cea3d10] [c000000000119034] .task_work_run+0x114/0x150
[ 1917.130912] [c00000004cea3db0] [c00000000001ba6c] .do_notify_resume+0xcc/0x100
[ 1917.130916] [c00000004cea3e30] [c00000000000a7b0] .ret_from_except_lite+0x5c/0x60
[ 1917.130919] Instruction dump:
[ 1917.130921] 7fc3f378 486734b5 60000000 387f00a0 38800003 4bdcb365 60000000 e95f00a0
[ 1917.130927] 694a0060 7d4a0074 794ad182 694a0001 <0b0a0000> 892d02a4 2f890000 40de0134
Signed-off-by: NScott Mayhew <smayhew@redhat.com>
Cc: stable@vger.kernel.org # 4.5+
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

The following deadlock can occur between a process waiting for a client
to initialize in while walking the client list during nfsv4 server trunking
detection and another process waiting for the nfs_clid_init_mutex so it
can initialize that client:

Process 1                               Process 2
---------                               ---------
spin_lock(&nn->nfs_client_lock);
list_add_tail(&CLIENTA->cl_share_link,
        &nn->nfs_client_list);
spin_unlock(&nn->nfs_client_lock);
                                        spin_lock(&nn->nfs_client_lock);
                                        list_add_tail(&CLIENTB->cl_share_link,
                                                &nn->nfs_client_list);
                                        spin_unlock(&nn->nfs_client_lock);
                                        mutex_lock(&nfs_clid_init_mutex);
                                        nfs41_walk_client_list(clp, result, cred);
                                        nfs_wait_client_init_complete(CLIENTA);
(waiting for nfs_clid_init_mutex)

Make sure nfs_match_client() only evaluates clients that have completed
initialization in order to prevent that deadlock.

This patch also fixes v4.0 trunking behavior by not marking the client
NFS_CS_READY until the clientid has been confirmed.
Signed-off-by: NScott Mayhew <smayhew@redhat.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

gcc 4.4.4 is too old to have full C11 anonymous union support, so
the current initialiser fails to compile.
Reported-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
(compile-)Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

This is a pure automated search-and-replace of the internal kernel
superblock flags.

The s_flags are now called SB_*, with the names and the values for the
moment mirroring the MS_* flags that they're equivalent to.

Note how the MS_xyz flags are the ones passed to the mount system call,
while the SB_xyz flags are what we then use in sb->s_flags.

The script to do this was:

    # places to look in; re security/*: it generally should *not* be
    # touched (that stuff parses mount(2) arguments directly), but
    # there are two places where we really deal with superblock flags.
    FILES="drivers/mtd drivers/staging/lustre fs ipc mm \
            include/linux/fs.h include/uapi/linux/bfs_fs.h \
            security/apparmor/apparmorfs.c security/apparmor/include/lib.h"
    # the list of MS_... constants
    SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \
          DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \
          POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \
          I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \
          ACTIVE NOUSER"

    SED_PROG=
    for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done

    # we want files that contain at least one of MS_...,
    # with fs/namespace.c and fs/pnode.c excluded.
    L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c')

    for f in $L; do sed -i $f $SED_PROG; done
Requested-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit e1293727 "NFS: Move the flock open mode check into nfs_flock()"
changed NFSv3 behavior for flock() such that the open mode must match the
lock type, however that requirement shouldn't be enforced for flock().
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Cc: stable@vger.kernel.org # v4.12
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

The option was incorrectly masking off all other options.
Signed-off-by: NJoshua Watt <JPEWhacker@gmail.com>
Cc: stable@vger.kernel.org #3.7
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Before traversing a referral and performing a mount, the mounted-on
directory looks strange:

dr-xr-xr-x. 2 4294967294 4294967294 0 Dec 31  1969 dir.0

nfs4_get_referral is wiping out any cached attributes with what was
returned via GETATTR(fs_locations), but the bit mask for that
operation does not request any file attributes.

Retrieve owner and timestamp information so that the memcpy in
nfs4_get_referral fills in more attributes.

Changes since v1:
- Don't request attributes that the client unconditionally replaces
- Request only MOUNTED_ON_FILEID or FILEID attribute, not both
- encode_fs_locations() doesn't use the third bitmask word

Fixes: 6b97fd3d ("NFSv4: Follow a referral")
Suggested-by: NPradeep Thomas <pradeepthomas@gmail.com>
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Addresses-Coverity-ID: 703509
Addresses-Coverity-ID: 703510
Addresses-Coverity-ID: 703511
Addresses-Coverity-ID: 703512
Addresses-Coverity-ID: 703513
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>