Add "page groups" - a circular list of nfs requests (struct nfs_page)
that all reference the same page. This gives nfs read and write paths
the ability to account for sub-page regions independently.  This
somewhat follows the design of struct buffer_head's sub-page
accounting.

Only "head" requests are ever added/removed from the inode list in
the buffered write path. "head" and "sub" requests are treated the
same through the read path and the rest of the write/commit path.
Requests are given an extra reference across the life of the list.

Page groups are never rejoined after being split. If the read/write
request fails and the client falls back to another path (ie revert
to MDS in PNFS case), the already split requests are pushed through
the recoalescing code again, which may split them further and then
coalesce them into properly sized requests on the wire. Fragmentation
shouldn't be a problem with the current design, because we flush all
requests in page group when a non-contiguous request is added, so
the only time resplitting should occur is on a resend of a read or
write.

This patch lays the groundwork for sub-page splitting, but does not
actually do any splitting. For now all page groups have one request
as pg_test functions don't yet split pages. There are several related
patches that are needed support multiple requests per page group.
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Call nfs_can_coalesce_requests for every request, even the first one.
This is needed for future patches to give pg_test a way to inform
add_request to reduce the size of the request.

Now @prev can be null in nfs_can_coalesce_requests and pg_test functions.
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

This is a step toward allowing pg_test to inform the the
coalescing code to reduce the size of requests so they may fit in
whatever scheme the pg_test callback wants to define.

For now, just return the size of the request if there is space, or 0
if there is not.  This shouldn't change any behavior as it acts
the same as when the pg_test functions returned bool.
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

@inode is passed but not used.
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Remove unused flags PG_NEED_COMMIT and PG_NEED_RESCHED.
Add comments describing how each flag is used.
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Hold the lock while modifying commit info dataserver buckets.

The following oops can be reproduced by running iozone for a while against
a 2 DS pynfs filelayout server.

general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC
Modules linked in: nfs_layout_nfsv41_files rpcsec_gss_krb5 nfsv4 nfs fscache
CPU: 0 PID: 903 Comm: iozone Not tainted 3.15.0-rc1-branch-dros_testing+ #44
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference
task: ffff880078164480 ti: ffff88006e972000 task.ti: ffff88006e972000
RIP: 0010:[<ffffffffa01936e1>]  [<ffffffffa01936e1>] nfs_init_commit+0x22/0x
RSP: 0018:ffff88006e973d30  EFLAGS: 00010246
RAX: ffff88006e973e00 RBX: ffff88006e828800 RCX: ffff88006e973e10
RDX: 0000000000000000 RSI: ffff88006e973e00 RDI: dead4ead00000000
RBP: ffff88006e973d38 R08: ffff88006e8289d8 R09: 0000000000000000
R10: ffff88006e8289d8 R11: 0000000000016988 R12: ffff88006e973b98
R13: ffff88007a0a6648 R14: ffff88006e973e10 R15: ffff88006e828800
FS:  00007f2ce396b740(0000) GS:ffff88007f200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f03278a1000 CR3: 0000000079043000 CR4: 00000000001407f0
Stack:
ffff88006e8289d8 ffff88006e973da8 ffffffffa00f144f ffff88006e9478c0
ffff88006e973e00 ffff88006de21080 0000000100000002 ffff880079be6c48
ffff88006e973d70 ffff88006e973d70 ffff88006e973e10 ffff88006de21080
Call Trace:
[<ffffffffa00f144f>] filelayout_commit_pagelist+0x1ae/0x34a [nfs_layout_nfsv
[<ffffffffa0194f72>] nfs_generic_commit_list+0x92/0xc4 [nfs]
[<ffffffffa0195053>] nfs_commit_inode+0xaf/0x114 [nfs]
[<ffffffffa01892bd>] nfs_file_fsync_commit+0x82/0xbe [nfs]
[<ffffffffa01ceb0d>] nfs4_file_fsync+0x59/0x9b [nfsv4]
[<ffffffff8114ee3c>] vfs_fsync_range+0x18/0x20
[<ffffffff8114ee60>] vfs_fsync+0x1c/0x1e
[<ffffffffa01891c2>] nfs_file_flush+0x7f/0x84 [nfs]
[<ffffffff81127a43>] filp_close+0x3c/0x72
[<ffffffff81140e12>] __close_fd+0x82/0x9a
[<ffffffff81127a9c>] SyS_close+0x23/0x4c
[<ffffffff814acd12>] system_call_fastpath+0x16/0x1b
Code: 5b 41 5c 41 5d 41 5e 5d c3 0f 1f 44 00 00 55 48 89 e5 53 48 89 fb 48 8
RIP  [<ffffffffa01936e1>] nfs_init_commit+0x22/0xe1 [nfs]
RSP <ffff88006e973d30>
---[ end trace 732fe6419b235e2f ]---
Suggested-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

At this point the read and write structures look identical, so combine
them into something shared by both.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

What we have here is two functions that look identical.  Let's share
some more code!
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Once again, these two functions look identical in the read and write
case.  Time to combine them together!
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Most of this code is the same for both the read and write paths, so
combine everything and use the rw_ops when necessary.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

These functions are almost identical on both the read and write side.
FLUSH_COND_STABLE will never be set for the read path, so leaving it in
the generic code won't hurt anything.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

At this point, the read and write versions of this function look
identical so both should use the same function.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Write adds a little bit of code dealing with flush flags, but since
"how" will always be 0 when reading we can share the code.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The read and write paths set up this struct in exactly the same way, so
create a single shared struct.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Combining these functions will let me make a single nfs_rw_common_ops
struct (see the next patch).
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The read and write paths do exactly the same thing for the rpc_prepare
rpc_op.  This patch combines them together into a single function.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

I create a new struct nfs_rw_ops to decide the differences between reads
and writes.  This struct will be set when initializing a new
nfs_pgio_descriptor, and then passed on to the nfs_rw_header when a new
header is allocated.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

These functions are identical for the read and write paths so they can
be combined.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The header had a pointer to the verifier that was set from the old write
data struct.  We don't need to keep the pointer around now that we have
shared structures.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The only difference is the write verifier field, but we can keep that
for a little bit longer.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

At this point, the only difference between nfs_read_data and
nfs_write_data is the write verifier.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Reads and writes have very similar results.  This patch combines the two
structs together with comments to show where the differing fields are
used.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Reads and writes have very similar arguments.  This patch combines them
together and documents the few fields used only by write.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The read_pageio_init method is just a very convoluted way to grab the
right nfs_pageio_ops vector.  The vector to chose is not a choice of
protocol version, but just a pNFS vs MDS I/O choice that can simply be
done inside nfs_pageio_init_read based on the presence of a layout
driver, and a new force_mds flag to the special case of falling back
to MDS I/O on a pNFS-capable volume.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The write_pageio_init method is just a very convoluted way to grab the
right nfs_pageio_ops vector.  The vector to chose is not a choice of
protocol version, but just a pNFS vs MDS I/O choice that can simply be
done inside nfs_pageio_init_write based on the presence of a layout
driver, and a new force_mds flag to the special case of falling back
to MDS I/O on a pNFS-capable volume.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

 "fdatasync() is similar to fsync(), but does not flush modified metadata
  unless that metadata is needed in order  to  allow  a  subsequent  data
  retrieval to be correctly handled."

We absolutely need to commit the layouts to be able to retrieve the data
in case either the client, the server or the storage subsystem go down.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

We're not taking a reference in the case where _gss_mech_get_by_pseudoflavor
loops without finding the correct rpcsec_gss flavour, so why are we
releasing it?
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If we suspect that the server may have cleared the suid/sgid bit,
then mark the inode for revalidation.
Reported-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Fix a bug, whereby nfs_update_inode() was declaring the inode to be
up to date despite not having checked all the attributes.
The bug occurs because the temporary variable in which we cache
the validity information is 'sanitised' before reapplying to
nfsi->cache_validity.
Reported-by: Kinglong Mee <kinglongmee@gmail.com>
Cc: stable@vger.kernel.org # 3.5+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

When double mounting same nfs filesystem, the devname saved in d_fsdata
will be lost.The second mount should not change the devname that
be saved in d_fsdata.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Some versions of gcc even warn about it:

  mm/shmem.c: In function ‘shmem_file_aio_read’:
  mm/shmem.c:1414: warning: ‘error’ may be used uninitialized in this function

If the loop is aborted during the first iteration by one of the two
first break statements, error will be uninitialized.

Introduced by commit 6e58e79d ("introduce copy_page_to_iter, kill
loop over iovec in generic_file_aio_read()").
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

On 32 bit, size_t is "unsigned int", not "unsigned long", causing the
following warning when comparing with PAGE_SIZE, which is always "unsigned
long":

  fs/cifs/file.c: In function ‘cifs_readdata_to_iov’:
  fs/cifs/file.c:2757: warning: comparison of distinct pointer types lacks a cast

Introduced by commit 7f25bba8 ("cifs_iovec_read: keep iov_iter
between the calls of cifs_readdata_to_iov()"), which changed the
signedness of "remaining" and the code from min_t() to min().
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull slab changes from Pekka Enberg:
 "The biggest change is byte-sized freelist indices which reduces slab
  freelist memory usage:

    https://lkml.org/lkml/2013/12/2/64"

* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  mm: slab/slub: use page->list consistently instead of page->lru
  mm/slab.c: cleanup outdated comments and unify variables naming
  slab: fix wrongly used macro
  slub: fix high order page allocation problem with __GFP_NOFAIL
  slab: Make allocations with GFP_ZERO slightly more efficient
  slab: make more slab management structure off the slab
  slab: introduce byte sized index for the freelist of a slab
  slab: restrict the number of objects in a slab
  slab: introduce helper functions to get/set free object
  slab: factor out calculate nr objects in cache_estimate

Pull misc kbuild changes from Michal Marek:
 "Here is the non-critical part of kbuild:
   - One bogus coccinelle check removed, one check fixed not to suggest
     the obsolete PTR_RET macro
   - scripts/tags.sh does not index the generated *.mod.c files
   - new objdiff tool to list differences between two versions of an
     object file
   - A fix for scripts/bootgraph.pl"

* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  scripts/coccinelle: Use PTR_ERR_OR_ZERO
  scripts/bootgraph.pl: Add graphic header
  scripts: objdiff: detect object code changes between two commits
  Coccicheck: Remove memcpy to struct assignment test
  scripts/tags.sh: Ignore *.mod.c

This patch fixes I/O errors with the sym53c8xx_2 driver when the disk
returns QUEUE FULL status.

When the controller encounters an error (including QUEUE FULL or BUSY
status), it aborts all not yet submitted requests in the function
sym_dequeue_from_squeue.

This function aborts them with DID_SOFT_ERROR.

If the disk has full tag queue, the request that caused the overflow is
aborted with QUEUE FULL status (and the scsi midlayer properly retries
it until it is accepted by the disk), but the sym53c8xx_2 driver aborts
the following requests with DID_SOFT_ERROR --- for them, the midlayer
does just a few retries and then signals the error up to sd.

The result is that disk returning QUEUE FULL causes request failures.

The error was reproduced on 53c895 with COMPAQ BD03685A24 disk
(rebranded ST336607LC) with command queue 48 or 64 tags.  The disk has
64 tags, but under some access patterns it return QUEUE FULL when there
are less than 64 pending tags.  The SCSI specification allows returning
QUEUE FULL anytime and it is up to the host to retry.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 8f619b54 ("powerpc/ppc64: Do not turn AIL (reloc-on
interrupts) too early") added code to set the AIL bit in the LPCR
without checking whether the kernel is running in hypervisor mode.  The
result is that when the kernel is running as a guest (i.e., under
PowerKVM or PowerVM), the processor takes a privileged instruction
interrupt at that point, causing a panic.  The visible result is that
the kernel hangs after printing "returning from prom_init".

This fixes it by checking for hypervisor mode being available before
setting LPCR.  If we are not in hypervisor mode, we enable relocation-on
interrupts later in pSeries_setup_arch using the H_SET_MODE hcall.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commits 11d4616b ("futex: revert back to the explicit waiter
counting code") and 69cd9eba ("futex: avoid race between requeue and
wake") changed some of the finer details of how we think about futexes.
One was a late fix and the other a consequence of overlooking the whole
requeuing logic.

The first change caused our documentation to be incorrect, and the
second made us aware that we need to explicitly add more details to it.
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull yet more networking updates from David Miller:

 1) Various fixes to the new Redpine Signals wireless driver, from
    Fariya Fatima.

 2) L2TP PPP connect code takes PMTU from the wrong socket, fix from
    Dmitry Petukhov.

 3) UFO and TSO packets differ in whether they include the protocol
    header in gso_size, account for that in skb_gso_transport_seglen().
   From Florian Westphal.

 4) If VLAN untagging fails, we double free the SKB in the bridging
    output path.  From Toshiaki Makita.

 5) Several call sites of sk->sk_data_ready() were referencing an SKB
    just added to the socket receive queue in order to calculate the
    second argument via skb->len.  This is dangerous because the moment
    the skb is added to the receive queue it can be consumed in another
    context and freed up.

    It turns out also that none of the sk->sk_data_ready()
    implementations even care about this second argument.

    So just kill it off and thus fix all these use-after-free bugs as a
    side effect.

 6) Fix inverted test in tcp_v6_send_response(), from Lorenzo Colitti.

 7) pktgen needs to do locking properly for LLTX devices, from Daniel
    Borkmann.

 8) xen-netfront driver initializes TX array entries in RX loop :-) From
    Vincenzo Maffione.

 9) After refactoring, some tunnel drivers allow a tunnel to be
    configured on top itself.  Fix from Nicolas Dichtel.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (46 commits)
  vti: don't allow to add the same tunnel twice
  gre: don't allow to add the same tunnel twice
  drivers: net: xen-netfront: fix array initialization bug
  pktgen: be friendly to LLTX devices
  r8152: check RTL8152_UNPLUG
  net: sun4i-emac: add promiscuous support
  net/apne: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO
  net: ipv6: Fix oif in TCP SYN+ACK route lookup.
  drivers: net: cpsw: enable interrupts after napi enable and clearing previous interrupts
  drivers: net: cpsw: discard all packets received when interface is down
  net: Fix use after free by removing length arg from sk_data_ready callbacks.
  Drivers: net: hyperv: Address UDP checksum issues
  Drivers: net: hyperv: Negotiate suitable ndis version for offload support
  Drivers: net: hyperv: Allocate memory for all possible per-pecket information
  bridge: Fix double free and memory leak around br_allowed_ingress
  bonding: Remove debug_fs files when module init fails
  i40evf: program RSS LUT correctly
  i40evf: remove open-coded skb_cow_head
  ixgb: remove open-coded skb_cow_head
  igbvf: remove open-coded skb_cow_head
  ...

Merge tag 'blackfin-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/realmz6/blackfin-linux

Pull blackfin updates from Steven Miao:
 "Code cleanup, some previously ignored patches, and bug fixes"

* tag 'blackfin-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/realmz6/blackfin-linux:
  blackfin: cleanup board files
  bf609: clock: drop unused clock bit set/clear functions
  Blackfin: bf537: rename "CONFIG_ADT75"
  Blackfin: bf537: rename "CONFIG_AD7314"
  Blackfin: bf537: rename ad2s120x ->ad2s1200
  blackfin: bf537: fix typo "CONFIG_SND_SOC_ADV80X_MODULE"
  blackfin: dma: current count mmr is read only
  bfin_crc: Move architecture independant crc header file out of the blackfin folder.
  bf54x: drop unuesd HOST status,control,timeout registers bit define macros
  blackfin: portmux: cleanup head file
  Blackfin: remove "config IP_CHECKSUM_L1"
  blackfin: Remove GENERIC_GPIO config option again
  blackfin:Use generic /proc/interrupts implementation
  blackfin: bf60x: fix typo "CONFIG_PM_BFIN_WAKE_PA15_POL"