This causes a small behaviour change in that we don't bother to set
ACLs on file creation if the mode bit can express the access permissions
fully, and thus behaving identical to local filesystems.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Rename the current posix_acl_created to __posix_acl_create and add
a fully featured helper to set up the ACLs on file creation that
uses get_acl().
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

When compiling a 32bit kernel with CONFIG_LBDAF=n the compiler complains like
shown below.  Fix this warning by instead using sector_div() which is provided
by the kernel.h header file.

fs/nfs/blocklayout/extents.c: In function ‘normalize’:
include/asm-generic/div64.h:43:28: warning: comparison of distinct pointer types lacks a cast [enabled by default]
fs/nfs/blocklayout/extents.c:47:13: note: in expansion of macro ‘do_div’
nfs/blocklayout/extents.c:47:2: warning: right shift count >= width of type [enabled by default]
fs/nfs/blocklayout/extents.c:47:2: warning: passing argument 1 of ‘__div64_32’ from incompatible pointer type [enabled by default]
include/asm-generic/div64.h:35:17: note: expected ‘uint64_t *’ but argument is of type ‘sector_t *’
 extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
Signed-off-by: NHelge Deller <deller@gmx.de>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Andy Adamson reports:

The state manager is recovering expired state and recovery OPENs are being
processed. If kswapd is pruning inodes at the same time, a deadlock can occur
when kswapd calls evict_inode on an NFSv4.1 inode with a layout, and the
resultant layoutreturn gets an error that the state mangager is to handle,
causing the layoutreturn to wait on the (NFS client) cl_rpcwaitq.

At the same time an open is waiting for the inode deletion to complete in
__wait_on_freeing_inode.

If the open is either the open called by the state manager, or an open from
the same open owner that is holding the NFSv4 sequence id which causes the
OPEN from the state manager to wait for the sequence id on the Seqid_waitqueue,
then the state is deadlocked with kswapd.

The fix is simply to have layoutreturn ignore all errors except NFS4ERR_DELAY.
We already know that layouts are dropped on all server reboots, and that
it has to be coded to deal with the "forgetful client model" that doesn't
send layoutreturns.
Reported-by: NAndy Adamson <andros@netapp.com>
Link: http://lkml.kernel.org/r/1385402270-14284-1-git-send-email-andros@netapp.comSigned-off-by: NTrond Myklebust <Trond.Myklebust@primarydata.com>

Also ensure that we zero out the stateid mode when exiting
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the DELEGRETURN errors out with something like NFS4ERR_BAD_STATEID
then there is no recovery possible. Just quit without returning an error.

Also, note that the client must not assume that the NFSv4 lease has been
renewed when it sees an error on DELEGRETURN.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

When the state manager is processing the NFS4CLNT_DELEGRETURN flag, session
draining is off, but DELEGRETURN can still get a session error.
The async handler calls nfs4_schedule_session_recovery returns -EAGAIN, and
the DELEGRETURN done then restarts the RPC task in the prepare state.
With the state manager still processing the NFS4CLNT_DELEGRETURN flag with
session draining off, these DELEGRETURNs will cycle with errors filling up the
session slots.

This prevents OPEN reclaims (from nfs_delegation_claim_opens) required by the
NFS4CLNT_DELEGRETURN state manager processing from completing, hanging the
state manager in the __rpc_wait_for_completion_task in nfs4_run_open_task
as seen in this kernel thread dump:

kernel: 4.12.32.53-ma D 0000000000000000     0  3393      2 0x00000000
kernel: ffff88013995fb60 0000000000000046 ffff880138cc5400 ffff88013a9df140
kernel: ffff8800000265c0 ffffffff8116eef0 ffff88013fc10080 0000000300000001
kernel: ffff88013a4ad058 ffff88013995ffd8 000000000000fbc8 ffff88013a4ad058
kernel: Call Trace:
kernel: [<ffffffff8116eef0>] ? cache_alloc_refill+0x1c0/0x240
kernel: [<ffffffffa0358110>] ? rpc_wait_bit_killable+0x0/0xa0 [sunrpc]
kernel: [<ffffffffa0358152>] rpc_wait_bit_killable+0x42/0xa0 [sunrpc]
kernel: [<ffffffff8152914f>] __wait_on_bit+0x5f/0x90
kernel: [<ffffffffa0358110>] ? rpc_wait_bit_killable+0x0/0xa0 [sunrpc]
kernel: [<ffffffff815291f8>] out_of_line_wait_on_bit+0x78/0x90
kernel: [<ffffffff8109b520>] ? wake_bit_function+0x0/0x50
kernel: [<ffffffffa035810d>] __rpc_wait_for_completion_task+0x2d/0x30 [sunrpc]
kernel: [<ffffffffa040d44c>] nfs4_run_open_task+0x11c/0x160 [nfs]
kernel: [<ffffffffa04114e7>] nfs4_open_recover_helper+0x87/0x120 [nfs]
kernel: [<ffffffffa0411646>] nfs4_open_recover+0xc6/0x150 [nfs]
kernel: [<ffffffffa040cc6f>] ? nfs4_open_recoverdata_alloc+0x2f/0x60 [nfs]
kernel: [<ffffffffa0414e1a>] nfs4_open_delegation_recall+0x6a/0xa0 [nfs]
kernel: [<ffffffffa0424020>] nfs_end_delegation_return+0x120/0x2e0 [nfs]
kernel: [<ffffffff8109580f>] ? queue_work+0x1f/0x30
kernel: [<ffffffffa0424347>] nfs_client_return_marked_delegations+0xd7/0x110 [nfs]
kernel: [<ffffffffa04225d8>] nfs4_run_state_manager+0x548/0x620 [nfs]
kernel: [<ffffffffa0422090>] ? nfs4_run_state_manager+0x0/0x620 [nfs]
kernel: [<ffffffff8109b0f6>] kthread+0x96/0xa0
kernel: [<ffffffff8100c20a>] child_rip+0xa/0x20
kernel: [<ffffffff8109b060>] ? kthread+0x0/0xa0
kernel: [<ffffffff8100c200>] ? child_rip+0x0/0x20

The state manager can not therefore process the DELEGRETURN session errors.
Change the async handler to wait for recovery on session errors.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Fix the following warning:

linux-nfs/fs/nfs/inode.c:315:1: warning: ‘inline’ is not at
beginning of declaration [-Wold-style-declaration]
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When CONFIG_NFS_V4_2 is toggled nfsd and lockd will be recompiled,
instead of only the nfs client.  This patch moves a small amount of code
into the client directory to avoid unnecessary recompiles.
Signed-off-by: NAnna Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Defaulting to m seem to prevent building the pnfs layout modules into the
kernel.  Default to the value of CONFIG_NFS_V4 make sure they are
built in for built-in NFSv4 support and modular for a modular NFSv4.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The current test on valid use of the "migration" mount option can never
report an error as it will only do so if
    mnt->version !=4 && mnt->minor_version != 0
(and some other condition), but if that test would succeed, then the previous
test has already gone-to  out_minorversion_mismatch.

So change the && to an || to get correct semantics.
Signed-off-by: NNeilBrown <neilb@suse.de>
Acked-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Use this new function to make code more comprehensible, since we are
reinitialzing the completion, not initializing.

[akpm@linux-foundation.org: linux-next resyncs]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, when we try to mount and get back NFS4ERR_CLID_IN_USE or
NFS4ERR_WRONGSEC, we create a new rpc_clnt and then try the call again.
There is no guarantee that doing so will work however, so we can end up
retrying the call in an infinite loop.

Worse yet, we create the new client using rpc_clone_client_set_auth,
which creates the new client as a child of the old one. Thus, we can end
up with a *very* long lineage of rpc_clnts. When we go to put all of the
references to them, we can end up with a long call chain that can smash
the stack as each rpc_free_client() call can recurse back into itself.

This patch fixes this by simply ensuring that the SETCLIENTID call will
only be retried in this situation if the last attempt did not use
RPC_AUTH_UNIX.

Note too that with this change, we don't need the (i > 2) check in the
-EACCES case since we now have a more reliable test as to whether we
should reattempt.

Cc: stable@vger.kernel.org # v3.10+
Cc: Chuck Lever <chuck.lever@oracle.com>
Tested-by/Acked-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We already check for nfs_server_capable(inode, NFS_CAP_SECURITY_LABEL)
in nfs4_label_alloc()
We check the minor version in _nfs4_server_capabilities before setting
NFS_CAP_SECURITY_LABEL.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We don't want to be setting capabilities and/or requesting attributes
that are not appropriate for the NFSv4 minor version.

- Ensure that we clear the NFS_CAP_SECURITY_LABEL capability when appropriate
- Ensure that we limit the attribute bitmasks to the mounted_on_fileid
  attribute and less for NFSv4.0
- Ensure that we limit the attribute bitmasks to suppattr_exclcreat and
  less for NFSv4.1
- Ensure that we limit it to change_sec_label or less for NFSv4.2
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, if the server is doing NFSv4.2 and supports labeled NFS, then
our on-the-wire READDIR request ends up asking for the label information,
which is then ignored unless we're doing readdirplus.
This patch ensures that READDIR doesn't ask the server for label information
at all unless the readdir->bitmask contains the FATTR4_WORD2_SECURITY_LABEL
attribute, and the readdir->plus flag is set.

While we're at it, optimise away the 3rd bitmap field if it is zero.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, we fetch the security label when revalidating an inode's
attributes, but don't apply it. This is in contrast to the readdir()
codepath where we do apply label changes.

Cc: Dave Quigley <dpquigl@davequigley.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ensure that _nfs4_do_get_security_label() also initialises the
SEQUENCE call correctly, by having it call into nfs4_call_sync().
Reported-by: NJeff Layton <jlayton@redhat.com>
Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Chao reported the following oops when testing labeled NFS:

BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffffa0568703>] nfs4_xdr_enc_setattr+0x43/0x110 [nfsv4]
PGD 277bbd067 PUD 2777ea067 PMD 0
Oops: 0000 [#1] SMP
Modules linked in: rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache sg coretemp kvm_intel kvm crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel lrw gf128mul iTCO_wdt glue_helper ablk_helper cryptd iTCO_vendor_support bnx2 pcspkr serio_raw i7core_edac cdc_ether microcode usbnet edac_core mii lpc_ich i2c_i801 mfd_core shpchp ioatdma dca acpi_cpufreq mperf nfsd auth_rpcgss nfs_acl lockd sunrpc xfs libcrc32c sr_mod sd_mod cdrom crc_t10dif mgag200 syscopyarea sysfillrect sysimgblt i2c_algo_bit drm_kms_helper ata_generic ttm pata_acpi drm ata_piix libata megaraid_sas i2c_core dm_mirror dm_region_hash dm_log dm_mod
CPU: 4 PID: 25657 Comm: chcon Not tainted 3.10.0-33.el7.x86_64 #1
Hardware name: IBM System x3550 M3 -[7944OEJ]-/90Y4784     , BIOS -[D6E150CUS-1.11]- 02/08/2011
task: ffff880178397220 ti: ffff8801595d2000 task.ti: ffff8801595d2000
RIP: 0010:[<ffffffffa0568703>]  [<ffffffffa0568703>] nfs4_xdr_enc_setattr+0x43/0x110 [nfsv4]
RSP: 0018:ffff8801595d3888  EFLAGS: 00010296
RAX: 0000000000000000 RBX: ffff8801595d3b30 RCX: 0000000000000b4c
RDX: ffff8801595d3b30 RSI: ffff8801595d38e0 RDI: ffff880278b6ec00
RBP: ffff8801595d38c8 R08: ffff8801595d3b30 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801595d38e0
R13: ffff880277a4a780 R14: ffffffffa05686c0 R15: ffff8802765f206c
FS:  00007f2c68486800(0000) GS:ffff88027fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000027651a000 CR4: 00000000000007e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Stack:
 0000000000000000 0000000000000000 0000000000000000 0000000000000000
 0000000000000000 ffff880277865800 ffff880278b6ec00 ffff880277a4a780
 ffff8801595d3948 ffffffffa02ad926 ffff8801595d3b30 ffff8802765f206c
Call Trace:
 [<ffffffffa02ad926>] rpcauth_wrap_req+0x86/0xd0 [sunrpc]
 [<ffffffffa02a1d40>] ? call_connect+0xb0/0xb0 [sunrpc]
 [<ffffffffa02a1d40>] ? call_connect+0xb0/0xb0 [sunrpc]
 [<ffffffffa02a1ecb>] call_transmit+0x18b/0x290 [sunrpc]
 [<ffffffffa02a1d40>] ? call_connect+0xb0/0xb0 [sunrpc]
 [<ffffffffa02aae14>] __rpc_execute+0x84/0x400 [sunrpc]
 [<ffffffffa02ac40e>] rpc_execute+0x5e/0xa0 [sunrpc]
 [<ffffffffa02a2ea0>] rpc_run_task+0x70/0x90 [sunrpc]
 [<ffffffffa02a2f03>] rpc_call_sync+0x43/0xa0 [sunrpc]
 [<ffffffffa055284d>] _nfs4_do_set_security_label+0x11d/0x170 [nfsv4]
 [<ffffffffa0558861>] nfs4_set_security_label.isra.69+0xf1/0x1d0 [nfsv4]
 [<ffffffff815fca8b>] ? avc_alloc_node+0x24/0x125
 [<ffffffff815fcd2f>] ? avc_compute_av+0x1a3/0x1b5
 [<ffffffffa055897b>] nfs4_xattr_set_nfs4_label+0x3b/0x50 [nfsv4]
 [<ffffffff811bc772>] generic_setxattr+0x62/0x80
 [<ffffffff811bcfc3>] __vfs_setxattr_noperm+0x63/0x1b0
 [<ffffffff811bd1c5>] vfs_setxattr+0xb5/0xc0
 [<ffffffff811bd2fe>] setxattr+0x12e/0x1c0
 [<ffffffff811a4d22>] ? final_putname+0x22/0x50
 [<ffffffff811a4f2b>] ? putname+0x2b/0x40
 [<ffffffff811aa1cf>] ? user_path_at_empty+0x5f/0x90
 [<ffffffff8119bc29>] ? __sb_start_write+0x49/0x100
 [<ffffffff811bd66f>] SyS_lsetxattr+0x8f/0xd0
 [<ffffffff8160cf99>] system_call_fastpath+0x16/0x1b
Code: 48 8b 02 48 c7 45 c0 00 00 00 00 48 c7 45 c8 00 00 00 00 48 c7 45 d0 00 00 00 00 48 c7 45 d8 00 00 00 00 48 c7 45 e0 00 00 00 00 <48> 8b 00 48 8b 00 48 85 c0 0f 84 ae 00 00 00 48 8b 80 b8 03 00
RIP  [<ffffffffa0568703>] nfs4_xdr_enc_setattr+0x43/0x110 [nfsv4]
 RSP <ffff8801595d3888>
CR2: 0000000000000000

The problem is that _nfs4_do_set_security_label calls rpc_call_sync()
directly which fails to do any setup of the SEQUENCE call. Have it use
nfs4_call_sync() instead which does the right thing. While we're at it
change the name of "args" to "arg" to better match the pattern in
_nfs4_do_setattr.
Reported-by: NChao Ye <cye@redhat.com>
Cc: David Quigley <dpquigl@davequigley.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

commit 6686390b (NFS: remove incorrect "Lock reclaim failed!"
warning.) added a test for a delegation before checking to see if any
reclaimed locks failed. The test however is backward and is only doing
that check when a delegation is held instead of when one isn't.

Cc: NeilBrown <neilb@suse.de>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Fixes: 6686390b: NFS: remove incorrect "Lock reclaim failed!" warning.
Cc: stable@vger.kernel.org # 3.12
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This check was added by Al Viro with
d9e80b7d "nfs d_revalidate() is too
trigger-happy with d_drop()", with the explanation that we don't want to
remove the root of a disconnected tree, which will still be included on
the s_anon list.

But DCACHE_DISCONNECTED does *not* actually identify dentries that are
disconnected from the dentry tree or hashed on s_anon.  IS_ROOT() is the
way to do that.

Also add a comment from Al's commit to remind us why this check is
there.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Use 'PTR_ERR_OR_ZERO()' rather than 'IS_ERR(...) ? PTR_ERR(...) : 0'.
Signed-off-by: NGeyslan G. Bem <geyslan@gmail.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Use 'PTR_ERR_OR_ZERO()' rather than 'IS_ERR(...) ? PTR_ERR(...) : 0'.
Signed-off-by: NGeyslan G. Bem <geyslan@gmail.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

the 'error' variable was been assigned twice in vain.
Signed-off-by: NGeyslan G. Bem <geyslan@gmail.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch adds support for multiple security options which can be
specified using a colon-delimited list of security flavors (the same
syntax as nfsd's exports file).

This is useful, for instance, when NFSv4.x mounts cross SECINFO
boundaries. With this patch a user can use "sec=krb5i,krb5p"
to mount a remote filesystem using krb5i, but can still cross
into krb5p-only exports.

New mounts will try all security options before failing.  NFSv4.x
SECINFO results will be compared against the sec= flavors to
find the first flavor in both lists or if no match is found will
return -EPERM.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Since the parsed sec= flavor is now stored in nfs_server->auth_info,
we no longer need an nfs_server flag to determine if a sec= option was
used.

This flag has not been completely removed because it is still needed for
the (old but still supported) non-text parsed mount options ABI
compatability.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Cache the auth_info structure in nfs_server and pass these values to submounts.

This lays the groundwork for supporting multiple sec= options.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When filling parsed_mount_data, store the parsed sec= mount option in
the new struct nfs_auth_info and the chosen flavor in selected_flavor.

This patch lays the groundwork for supporting multiple sec= options.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It's not used outside of nfs4namespace.c anymore.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

In nfs4_wait_clnt_recover(), hold a reference to the clp being
waited on.  The state manager can reduce clp->cl_count to 1, in
which case the nfs_put_client() in nfs4_run_state_manager() can
free *clp before wait_on_bit() returns and allows
nfs4_wait_clnt_recover() to run again.

The behavior at that point is non-deterministic.  If the waited-on
bit still happens to be zero, wait_on_bit() will wake the waiter as
expected.  If the bit is set again (say, if the memory was poisoned
when freed) wait_on_bit() can leave the waiter asleep.

This is a narrow fix which ensures the safety of accessing *clp in
nfs4_wait_clnt_recover(), but does not address the continued use
of a possibly freed *clp after nfs4_wait_clnt_recover() returns
(see nfs_end_delegation_return(), for example).
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Broadly speaking, v4.1 migration is untested.  There are no servers
in the wild that support NFSv4.1 migration.  However, as server
implementations become available, we do want to enable testing by
developers, while leaving it disabled for environments for which
broken migration support would be an unpleasant surprise.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

With the advent of NFSv4 sessions in NFSv4.1 and following, a "lease
moved" condition is reported differently than it is in NFSv4.0.

NFSv4 minor version 0 servers return an error status code,
NFS4ERR_LEASE_MOVED, to signal that a lease has moved.  This error
causes the whole compound operation to fail.  Normal compounds
against this server continue to fail until the client performs
migration recovery on the migrated share.

Minor version 1 and later servers assert a bit flag in the reply to
a compound's SEQUENCE operation to signal LEASE_MOVED.  This is not
a fatal condition: operations against this server continue normally.
The server asserts this flag until the client performs migration
recovery on the migrated share.

Note that servers MUST NOT return NFS4ERR_LEASE_MOVED to NFSv4
clients not using NFSv4.0.

After the server asserts any of the sr_status_flags in the SEQUENCE
operation in a typical compound, our client initiates standard lease
recovery.  For NFSv4.1+, a stand-alone SEQUENCE operation is
performed to discover what recovery is needed.

If SEQ4_STATUS_LEASE_MOVED is asserted in this stand-alone SEQUENCE
operation, our client attempts to discover which FSIDs have been
migrated, and then performs migration recovery on each.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

With NFSv4 minor version 0, the asynchronous lease RENEW
heartbeat can return NFS4ERR_LEASE_MOVED.  Error recovery logic for
async RENEW is a separate code path from the generic NFS proc paths,
so it must be updated to handle NFS4ERR_LEASE_MOVED as well.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently the Linux NFS client ignores the operation status code for
the RELEASE_LOCKOWNER operation.  Like NFSv3's UMNT operation,
RELEASE_LOCKOWNER is a courtesy to help servers manage their
resources, and the outcome is not consequential for the client.

During a migration, a server may report NFS4ERR_LEASE_MOVED, in
which case the client really should retry, since typically
LEASE_MOVED has nothing to do with the current operation, but does
prevent it from going forward.

Also, it's important for a client to respond as soon as possible to
a moved lease condition, since the client's lease could expire on
the destination without further action by the client.

NFS4ERR_DELAY is not included in the list of valid status codes for
RELEASE_LOCKOWNER in RFC 3530bis.  However, rfc3530-migration-update
does permit migration-capable servers to return DELAY to clients,
but only in the context of an ongoing migration.  In this case the
server has frozen lock state in preparation for migration, and a
client retry would help the destination server purge unneeded state
once migration recovery is complete.

Interestly, NFS4ERR_MOVED is not valid for RELEASE_LOCKOWNER, even
though lock owners can be migrated with Transparent State Migration.

Note that RFC 3530bis section 9.5 includes RELEASE_LOCKOWNER in the
list of operations that renew a client's lease on the server if they
succeed.  Now that our client pays attention to the operation's
status code, we can note that renewal appropriately.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Trigger lease-moved recovery when a request returns
NFS4ERR_LEASE_MOVED.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

A migration on the FSID in play for the current NFS operation
is reported via the error status code NFS4ERR_MOVED.

"Lease moved" means that a migration has occurred on some other
FSID than the one for the current operation.  It's a signal that
the client should take action immediately to handle a migration
that it may not have noticed otherwise.  This is so that the
client's lease does not expire unnoticed on the destination server.

In NFSv4.0, a moved lease is reported with the NFS4ERR_LEASE_MOVED
error status code.

To recover from NFS4ERR_LEASE_MOVED, check each FSID for that server
to see if it is still present.  Invoke nfs4_try_migration() if the
FSID is no longer present on the server.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Introduce a mechanism for probing a server to determine if an FSID
is present or absent.

The on-the-wire compound is different between minor version 0 and 1.
Minor version 0 appends a RENEW operation to identify which client
ID is probing.  Minor version 1 has a SEQUENCE operation in the
compound which effectively carries the same information.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When a server returns NFS4ERR_MOVED during a delegation recall,
trigger the new migration recovery logic in the state manager.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When a server returns NFS4ERR_MOVED, trigger the new migration
recovery logic in the state manager.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

I'm going to use this exit label also for migration recovery
failures.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>