The commit lists can get very large, so using the inode->i_lock can
end up affecting general metadata performance.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Doing the test without taking any locks is racy, and so really it makes
more sense to do it in the flexfiles code (which is the only case that
cares).
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

We must make sure that cinfo->ds->ncommitting is in sync with the
commit list, since it is checked as part of pnfs_commit_list().
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

We must make sure that cinfo->ds->nwritten is in sync with the
commit list, since it is checked as part of pnfs_scan_commit_lists().
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Signed-off-by: NFred Isaman <fred.isaman@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the layout segment is invalid, we want to just resend the remaining
writes.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the layout was invalidated, then assume we should requeue all the
pending writes for the DS in question.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

It is not used outside the NFSv4 module.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When passed GFP flags that allow sleeping (such as
GFP_NOIO), mempool_alloc() will never return NULL, it will
wait until memory is available.

This means that we don't need to handle failure, but that we
do need to ensure one thread doesn't call mempool_alloc()
twice on the one pool without queuing or freeing the first
allocation.  If multiple threads did this during times of
high memory pressure, the pool could be exhausted and a
deadlock could result.

pnfs_generic_alloc_ds_commits() attempts to allocate from
the nfs_commit_mempool while already holding an allocation
from that pool.  This is not safe.  So change
nfs_commitdata_alloc() to take a flag that indicates whether
failure is acceptable.

In pnfs_generic_alloc_ds_commits(), accept failure and
handle it as we currently do.  Else where, do not accept
failure, and do not handle it.

Even when failure is acceptable, we want to succeed if
possible.  That means both
 - using an entry from the pool if there is one
 - waiting for direct reclaim is there isn't.

We call mempool_alloc(GFP_NOWAIT) to achieve the first, then
kmem_cache_alloc(GFP_NOIO|__GFP_NORETRY) to achieve the
second.  Each of these can fail, but together they do the
best they can without blocking indefinitely.

The objects returned by kmem_cache_alloc() will still be freed
by mempool_free().  This is safe as mempool_alloc() uses
exactly the same function to allocate objects (since the mempool
was created with mempool_create_slab_pool()).  The object returned
by mempool_alloc() and kmem_cache_alloc() are indistinguishable
so mempool_free() will handle both identically, either adding to the
pool or calling kmem_cache_free().

Also, don't test for failure when allocating from
nfs_wdata_mempool.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The flexfiles layout should never mark a device unavailable.

Move nfs4_mark_deviceid_unavailable out of nfs4_pnfs_ds_connect and call
directly from files layout where it's still needed.

The flexfiles driver still handles marked devices in error paths, but will
now print a rate limited warning.
Signed-off-by: NWeston Andros Adamson <dros@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

The nfs4_pnfs_ds_connect path can call rpc_create which can fail or it
can wait on another context to reach the same failure.

This checks that the rpc_create succeeded and returns the error to the
caller.

When an error is returned, both the files and flexfiles layouts will return
NULL from _prepare_ds(). The flexfiles layout will also return the layout
with the error NFS4ERR_NXIO.
Signed-off-by: NWeston Andros Adamson <dros@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

This parameter hasn't been used since f8407299 (Linux 3.11-rc2), so
let's remove it from this function and callers.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Try all multipath addresses for a data server. The first address that
successfully connects and creates a session is the DS mount address.
All subsequent addresses are tested for session trunking and
added as aliases.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Signed-off-by: NTigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

result:

$ mount -o vers=4.1 dcache-lab007:/ /pnfs
$ cp /etc/profile /pnfs
tcp        0      0 131.169.185.68:1005     131.169.191.141:32049   ESTABLISHED
tcp        0      0 131.169.185.68:751      131.169.191.144:2049    ESTABLISHED
$

$ mount -o vers=4.1,noresvport dcache-lab007:/ /pnfs
$ cp /etc/profile /pnfs
tcp        0      0 131.169.185.68:34894    131.169.191.141:32049   ESTABLISHED
tcp        0      0 131.169.185.68:35722    131.169.191.144:2049    ESTABLISHED
$
Signed-off-by: NTigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

So ensure that we mark the layout for commit once the write is done,
and then ensure that the commit to ds is finished before sending
layoutcommit.

Note that by doing this, we're able to optimise away the commit
for the case of servers that don't need layoutcommit in order to
return updated attributes.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

pnfs_generic_commit_cancel_empty_pagelist calls nfs_commitdata_release,
but that is wrong: nfs_commitdata_release puts the open context, something
that isn't valid until nfs_init_commit is called, which is never the case
when pnfs_generic_commit_cancel_empty_pagelist is called.

This was introduced in "nfs: avoid race that crashes nfs_init_commit".
Signed-off-by: NWeston Andros Adamson <dros@primarydata.com>
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Since the patch "NFS: Allow multiple commit requests in flight per file"
we can run multiple simultaneous commits on the same inode.  This
introduced a race over collecting pages to commit that made it possible
to call nfs_init_commit() with an empty list - which causes crashes like
the one below.

The fix is to catch this race and avoid calling nfs_init_commit and
initiate_commit when there is no work to do.

Here is the crash:

[600522.076832] BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
[600522.078475] IP: [<ffffffffa0479e72>] nfs_init_commit+0x22/0x130 [nfs]
[600522.078745] PGD 4272b1067 PUD 4272cb067 PMD 0
[600522.078972] Oops: 0000 [#1] SMP
[600522.079204] Modules linked in: nfsv3 nfs_layout_flexfiles rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache dcdbas ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw vmw_vsock_vmci_transport vsock bonding ipmi_devintf ipmi_msghandler coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel ppdev vmw_balloon parport_pc parport acpi_cpufreq vmw_vmci i2c_piix4 shpchp nfsd auth_rpcgss nfs_acl lockd grace sunrpc xfs libcrc32c vmwgfx drm_kms_helper ttm drm crc32c_intel serio_raw vmxnet3
[600522.081380]  vmw_pvscsi ata_generic pata_acpi
[600522.081809] CPU: 3 PID: 15667 Comm: /usr/bin/python Not tainted 4.1.9-100.pd.88.el7.x86_64 #1
[600522.082281] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 09/30/2014
[600522.082814] task: ffff8800bbbfa780 ti: ffff88042ae84000 task.ti: ffff88042ae84000
[600522.083378] RIP: 0010:[<ffffffffa0479e72>]  [<ffffffffa0479e72>] nfs_init_commit+0x22/0x130 [nfs]
[600522.083973] RSP: 0018:ffff88042ae87438  EFLAGS: 00010246
[600522.084571] RAX: 0000000000000000 RBX: ffff880003485e40 RCX: ffff88042ae87588
[600522.085188] RDX: 0000000000000000 RSI: ffff88042ae874b0 RDI: ffff880003485e40
[600522.085756] RBP: ffff88042ae87448 R08: ffff880003486010 R09: ffff88042ae874b0
[600522.086332] R10: 0000000000000000 R11: 0000000000000005 R12: ffff88042ae872d0
[600522.086905] R13: ffff88042ae874b0 R14: ffff880003485e40 R15: ffff88042704c840
[600522.087484] FS:  00007f4728ff2740(0000) GS:ffff88043fd80000(0000) knlGS:0000000000000000
[600522.088070] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[600522.088663] CR2: 0000000000000040 CR3: 000000042b6aa000 CR4: 00000000001406e0
[600522.089327] Stack:
[600522.089926]  0000000000000001 ffff88042ae87588 ffff88042ae874f8 ffffffffa04f09fa
[600522.090549]  0000000000017840 0000000000017840 ffff88042ae87588 ffff8803258d9930
[600522.091169]  ffff88042ae87578 ffffffffa0563d80 0000000000000000 ffff88042704c840
[600522.091789] Call Trace:
[600522.092420]  [<ffffffffa04f09fa>] pnfs_generic_commit_pagelist+0x1da/0x320 [nfsv4]
[600522.093052]  [<ffffffffa0563d80>] ? ff_layout_commit_prepare_v3+0x30/0x30 [nfs_layout_flexfiles]
[600522.093696]  [<ffffffffa0562645>] ff_layout_commit_pagelist+0x15/0x20 [nfs_layout_flexfiles]
[600522.094359]  [<ffffffffa047bc78>] nfs_generic_commit_list+0xe8/0x120 [nfs]
[600522.095032]  [<ffffffffa047bd6a>] nfs_commit_inode+0xba/0x110 [nfs]
[600522.095719]  [<ffffffffa046ac54>] nfs_release_page+0x44/0xd0 [nfs]
[600522.096410]  [<ffffffff811a8122>] try_to_release_page+0x32/0x50
[600522.097109]  [<ffffffff811bd4f1>] shrink_page_list+0x961/0xb30
[600522.097812]  [<ffffffff811bdced>] shrink_inactive_list+0x1cd/0x550
[600522.098530]  [<ffffffff811bea65>] shrink_lruvec+0x635/0x840
[600522.099250]  [<ffffffff811bed60>] shrink_zone+0xf0/0x2f0
[600522.099974]  [<ffffffff811bf312>] do_try_to_free_pages+0x192/0x470
[600522.100709]  [<ffffffff811bf6ca>] try_to_free_pages+0xda/0x170
[600522.101464]  [<ffffffff811b2198>] __alloc_pages_nodemask+0x588/0x970
[600522.102235]  [<ffffffff811fbbd5>] alloc_pages_vma+0xb5/0x230
[600522.103000]  [<ffffffff813a1589>] ? cpumask_any_but+0x39/0x50
[600522.103774]  [<ffffffff811d6115>] wp_page_copy.isra.55+0x95/0x490
[600522.104558]  [<ffffffff810e3438>] ? __wake_up+0x48/0x60
[600522.105357]  [<ffffffff811d7d3b>] do_wp_page+0xab/0x4f0
[600522.106137]  [<ffffffff810a1bbb>] ? release_task+0x36b/0x470
[600522.106902]  [<ffffffff8126dbd7>] ? eventfd_ctx_read+0x67/0x1c0
[600522.107659]  [<ffffffff811da2a8>] handle_mm_fault+0xc78/0x1900
[600522.108431]  [<ffffffff81067ef1>] __do_page_fault+0x181/0x420
[600522.109173]  [<ffffffff811446a6>] ? __audit_syscall_exit+0x1e6/0x280
[600522.109893]  [<ffffffff810681c0>] do_page_fault+0x30/0x80
[600522.110594]  [<ffffffff81024f36>] ? syscall_trace_leave+0xc6/0x120
[600522.111288]  [<ffffffff81790a58>] page_fault+0x28/0x30
[600522.111947] Code: 5d c3 0f 1f 80 00 00 00 00 0f 1f 44 00 00 55 4c 8d 87 d0 01 00 00 48 89 e5 53 48 89 fb 48 83 ec 08 4c 8b 0e 49 8b 41 18 4c 39 ce <48> 8b 40 40 4c 8b 50 30 74 24 48 8b 87 d0 01 00 00 48 8b 7e 08
[600522.113343] RIP  [<ffffffffa0479e72>] nfs_init_commit+0x22/0x130 [nfs]
[600522.114003]  RSP <ffff88042ae87438>
[600522.114636] CR2: 0000000000000040

Fixes: af7cf057 (NFS: Allow multiple commit requests in flight per file)
CC: stable@vger.kernel.org
Signed-off-by: NWeston Andros Adamson <dros@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Commit ea2cf228 created nfs_commit_info and saved &inode->i_lock inside
this NFS specific structure.  This obscures the usage of i_lock.
Instead, save struct inode * so later it's clear the spinlock taken is
i_lock.

Should be no functional change.
Signed-off-by: NDave Wysochanski <dwysocha@redhat.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

This adds multipathing to pNFS over NFSv3 as described in the flexfiles
draft spec.
Ideally, we'd like to do the same for pNFS files, but the NFSv4.1 protocol
requires a call to EXCHANGE_ID in order to test that the connection can do
session trunking.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the layout segment is invalid, then we should not be adding more
write requests to the commit list. Instead, those writes should be
replayed after requesting a new layout.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Allow synchronous RPC calls to wait for pending RPC calls to finish,
but also allow asynchronous ones to just fire off another commit.

With this patch, the xfstests generic/074 test completes in 226s
instead of 242s
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We want to move commiting pages to pages list instead.
Otherwise it causes pnfs small writes crash like:

[34560.037692] BUG: unable to handle kernel NULL pointer dereference at 0000000000000068
[34560.038557] IP: [<ffffffffa05423d6>] nfs_init_commit+0x26/0x130 [nfs]
[34560.039400] PGD 69f5a067 PUD 69f59067 PMD 0
[34560.040207] Oops: 0000 [#1] SMP
[34560.041014] Modules linked in: nfsv3(OE) nfs_layout_flexfiles(OE) nfsv4(OE) nfs(OE) fscache(E) rpcsec_gss_krb5(E) xt_addrtype(E) xt_conntrack(E) ipt_MASQUERADE(E) nf_nat_masquerade_ipv4(E) iptable_nat(E) nf_conntrack_ipv4(E) nf_defrag_ipv4(E) nf_nat_ipv4(E) iptable_filter(E) ip_tables(E) x_tables(E) nf_nat(E) nf_conntrack(E) bridge(E) stp(E) llc(E) dm_thin_pool(E) dm_persistent_data(E) dm_bio_prison(E) dm_bufio(E) ppdev(E) vmw_balloon(E) coretemp(E) crc32_pclmul(E) ghash_clmulni_intel(E) aesni_intel(E) aes_x86_64(E) glue_helper(E) lrw(E) gf128mul(E) ablk_helper(E) cryptd(E) psmouse(E) serio_raw(E) vmw_vmci(E) i2c_piix4(E) shpchp(E) parport_pc(E) parport(E) mac_hid(E) nfsd(E) auth_rpcgss(E) nfs_acl(E) lockd(E) grace(E) sunrpc(E) xfs(E) libcrc32c(E) hid_generic(E) usbhid(E) hid(E) e1000(E) mptspi(E)
[34560.045106]  mptscsih(E) mptbase(E) vmwgfx(E) drm_kms_helper(E) ttm(E) drm(E) autofs4(E) [last unloaded: fscache]
[34560.045897] CPU: 0 PID: 130543 Comm: bash Tainted: G           OE   4.2.0-rc5-dp-00057-gf993a93 #11
[34560.046699] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/20/2014
[34560.047525] task: ffff880031b0a980 ti: ffff880045fec000 task.ti: ffff880045fec000
[34560.048264] RIP: 0010:[<ffffffffa05423d6>]  [<ffffffffa05423d6>] nfs_init_commit+0x26/0x130 [nfs]
[34560.049000] RSP: 0018:ffff880045fefc18  EFLAGS: 00010246
[34560.049717] RAX: 0000000000000000 RBX: ffff8800208fbc80 RCX: ffff880045fefd50
[34560.050396] RDX: ffff880031c19ec0 RSI: ffff880045fefc88 RDI: ffff8800208fbc80
[34560.051041] RBP: ffff880045fefc28 R08: ffff8800208fbe68 R09: ffff880045fefc88
[34560.051666] R10: 0000000000000000 R11: 0000000000000000 R12: ffff880045fefc78
[34560.052247] R13: ffff880045fefc88 R14: ffff880045fefa90 R15: ffff880045fefd50
[34560.052825] FS:  00007fa02d58c740(0000) GS:ffff88006d600000(0000) knlGS:0000000000000000
[34560.053410] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[34560.053992] CR2: 0000000000000068 CR3: 000000003b37a000 CR4: 00000000001406f0
[34560.054615] Stack:
[34560.055200]  ffff8800208fbc80 ffff8800208fbc80 ffff880045fefcc8 ffffffffa05c1a5b
[34560.055800]  ffff880045fefcc8 ffff880045fefd50 0000000045fefcb8 ffff880045fefd40
[34560.056418]  ffff8800420608e0 ffffffffa04f3910 0000000100000001 ffff880045fefd50
[34560.057013] Call Trace:
[34560.057672]  [<ffffffffa05c1a5b>] pnfs_generic_commit_pagelist+0x1cb/0x300 [nfsv4]
[34560.058277]  [<ffffffffa04f3910>] ? ff_layout_commit_pagelist+0x20/0x20 [nfs_layout_flexfiles]
[34560.058907]  [<ffffffffa04f3905>] ff_layout_commit_pagelist+0x15/0x20 [nfs_layout_flexfiles]
[34560.059557]  [<ffffffffa0543fc1>] nfs_generic_commit_list+0xb1/0xf0 [nfs]
[34560.060214]  [<ffffffffa0543e47>] ? nfs_scan_commit+0x37/0xa0 [nfs]
[34560.060825]  [<ffffffffa0544081>] nfs_commit_inode+0x81/0x150 [nfs]
[34560.061432]  [<ffffffffa05443ae>] nfs_wb_all+0x1ae/0x400 [nfs]
[34560.062035]  [<ffffffffa05380ad>] nfs_getattr+0x33d/0x510 [nfs]
[34560.062630]  [<ffffffff8122499c>] vfs_getattr_nosec+0x2c/0x40
[34560.063223]  [<ffffffff81224a66>] vfs_getattr+0x26/0x30
[34560.063818]  [<ffffffff81224b35>] vfs_fstatat+0x65/0xa0
[34560.064413]  [<ffffffff81224f3f>] SYSC_newstat+0x1f/0x40
[34560.065016]  [<ffffffff8102b176>] ? do_audit_syscall_entry+0x66/0x70
[34560.065626]  [<ffffffff8102c773>] ? syscall_trace_enter_phase1+0x113/0x170
[34560.066245]  [<ffffffff81003017>] ? trace_hardirqs_on_thunk+0x17/0x19
[34560.066868]  [<ffffffff812251ae>] SyS_newstat+0xe/0x10
[34560.067533]  [<ffffffff817a5df2>] entry_SYSCALL_64_fastpath+0x16/0x7a
[34560.068173] Code: 0f 1f 44 00 00 0f 1f 44 00 00 55 4c 8d 87 e8 01 00 00 48 89 e5 53 48 89 fb 48 83 ec 08 4c 8b 0e 49 8b 41 18 4c 39 ce 48 8b 40 40 <4c> 8b 50 68 74 24 48 8b 87 e8 01 00 00 48 8b 7e 08 4d 89 41 08
[34560.069609] RIP  [<ffffffffa05423d6>] nfs_init_commit+0x26/0x130 [nfs]
[34560.070295]  RSP <ffff880045fefc18>
[34560.071008] CR2: 0000000000000068
[34560.073207] ---[ end trace f85f873260977406 ]---

[fixes 27571297(pNFS: Tighten up locking around DS commit buckets)]
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

- Switch back to using list_for_each_entry(). Fixes an incorrect test
  for list NULL termination.
- Do not assume that lists are sorted.
- Finally, consider an existing entry to match if it consists of a subset
  of the addresses in the new entry.

Cc: stable@vger.kernel.org # 4.0+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

I'm not aware of any bugreports around this issue, but the locking
around the pnfs_commit_bucket is inconsistent at best. This patch
tightens it up by ensuring that the 'bucket->committing' list is always
changed atomically w.r.t. the 'bucket->clseg' layout segment tracking.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

pnfs_layout_mark_request_commit() needs to ensure that it adds the
request to the commit list atomically with all the other updates
in order to prevent corruption to buckets[ds_commit_idx].wlseg
due to races with pnfs_generic_clear_request_commit().

Fixes: 338d00cf ("pnfs: Refactor the *_layout_mark_request_commit...")
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The LAYOUTCOMMIT operation means different things to different layout types.
For blocks and objects, it is both a data and metadata consistency operation.
For files and flexfiles, it is only a metadata consistency operation.

This patch separates out the 2 cases, allowing the files/flexfiles layout
drivers to optimise away the data consistency calls to layoutcommit.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The function nfs4_pnfs_v3_ds_connect_unload is exported so it can be
used by other modules, but is also marked '__exit' and will be
discarded when built into the kernel, as pointed out by this
linker error:

`nfs4_pnfs_v3_ds_connect_unload' referenced in section `___ksymtab_gpl+nfs4_pnfs_v3_ds_connect_unload' of fs/built-in.o: defined in discarded section `.exit.text' of fs/built-in.o

This removes the __exit annotation to make it safe to call this function.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Fixes: 5f01d953 ("nfs41: create NFSv3 DS connection if specified")
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The File Layout's filelayout_mark_request_commit() is almost the
Flex File Layout's ff_layout_mark_request_commit(). And that can
be reduced by calling into nfs_request_add_commit_list().
Signed-off-by: NTom Haynes <loghyr@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Pass ds_commit_idx through the nfs commit path. It's used to select
the commit bucket when using pnfs and is ignored when not using pnfs.
Several functions had to be changed: nfs_retry_commit,
nfs_mark_request_commit, pnfs_mark_request_commit and the pnfs layout
driver .mark_request_commit functions.
Signed-off-by: NTom Haynes <loghyr@primarydata.com>

Instead of calling layoutreturn directly, call pnfs_error_mark_layout_for_return
to mark layouts for return and let generic code return layout when
layout segments are freed.
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTom Haynes <Thomas.Haynes@primarydata.com>

Conflicts:
	fs/nfs/filelayout/filelayout.c

pnfs flexfile layout client may want to use NFSv3 ops rather
than the default MDS v4 ops.
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTom Haynes <Thomas.Haynes@primarydata.com>

Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTom Haynes <Thomas.Haynes@primarydata.com>

flexfile layout may need to set such when making DS connections.
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTom Haynes <Thomas.Haynes@primarydata.com>

flexfile layout may use different auth flavor as specified by MDS.
Reviewed-by: NJeff Layton <jlayton@primarydata.com>
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTom Haynes <Thomas.Haynes@primarydata.com>

It can be reused by flexfiles layout client.
Reviewed-by: NJeff Layton <jlayton@primarydata.com>
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTom Haynes <Thomas.Haynes@primarydata.com>

It can be reused by flexfile layout.
Reviewed-by: NJeff Layton <jlayton@primarydata.com>
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTom Haynes <Thomas.Haynes@primarydata.com>

Also pull nfs4_pnfs_ds_addr and nfs4_pnfs_ds to generic pnfs.

They can all be reused by flexfile layout as well.
Reviewed-by: NJeff Layton <jlayton@primarydata.com>
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTom Haynes <Thomas.Haynes@primarydata.com>

Acked-by: NJeff Layton <jlayton@primarydata.com>
Signed-off-by: NTom Haynes <loghyr@primarydata.com>

The flexfilelayout driver will share some common code
with the filelayout driver. This set of changes refactors
that common code out to avoid any module depenencies.
Signed-off-by: NTom Haynes <loghyr@primarydata.com>