git.openwrt.org Git - openwrt/staging/blogic.git/log

SUNRPC: do not fail gss proc NULL calls with EACCES

Otherwise RPCSEC_GSS_DESTROY messages are not sent.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4: close needs to handle NFS4ERR_ADMIN_REVOKED

Also ensure that we zero out the stateid mode when exiting

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4: Update list of irrecoverable errors on DELEGRETURN

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: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

NFSv4 wait on recovery for async session errors

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: Andy Adamson <andros@netapp.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Fix a warning in nfs_setsecurity

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: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Enabling v4.2 should not recompile nfsd and lockd

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: Anna Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs: fix pnfs Kconfig defaults

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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: correctly report misuse of "migration" mount option.

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: NeilBrown <neilb@suse.de>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs: don't retry detect_trunking with RPC_AUTH_UNIX more than once

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: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Avoid deep recursion in rpc_release_client

In cases where an rpc client has a parent hierarchy, then
rpc_free_client may end up calling rpc_release_client() on the
parent, thus recursing back into rpc_free_client. If the hierarchy
is deep enough, then we can get into situations where the stack
simply overflows.

The fix is to have rpc_release_client() loop so that it can take
care of the parent rpc client hierarchy without needing to
recurse.

Reported-by: Jeff Layton <jlayton@redhat.com>
Reported-by: Weston Andros Adamson <dros@netapp.com>
Reported-by: Bruce Fields <bfields@fieldses.org>
Link: http://lkml.kernel.org/r/2C73011F-0939-434C-9E4D-13A1EB1403D7@netapp.com
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Fix a data corruption issue when retransmitting RPC calls

The following scenario can cause silent data corruption when doing
NFS writes. It has mainly been observed when doing database writes
using O_DIRECT.

1) The RPC client uses sendpage() to do zero-copy of the page data.
2) Due to networking issues, the reply from the server is delayed,
   and so the RPC client times out.

3) The client issues a second sendpage of the page data as part of
   an RPC call retransmission.

4) The reply to the first transmission arrives from the server
   _before_ the client hardware has emptied the TCP socket send
   buffer.
5) After processing the reply, the RPC state machine rules that
   the call to be done, and triggers the completion callbacks.
6) The application notices the RPC call is done, and reuses the
   pages to store something else (e.g. a new write).

7) The client NIC drains the TCP socket send buffer. Since the
   page data has now changed, it reads a corrupted version of the
   initial RPC call, and puts it on the wire.

This patch fixes the problem in the following manner:

The ordering guarantees of TCP ensure that when the server sends a
reply, then we know that the _first_ transmission has completed. Using
zero-copy in that situation is therefore safe.
If a time out occurs, we then send the retransmission using sendmsg()
(i.e. no zero-copy), We then know that the socket contains a full copy of
the data, and so it will retransmit a faithful reproduction even if the
RPC call completes, and the application reuses the O_DIRECT buffer in
the meantime.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

NFSv4.2: Remove redundant checks in nfs_setsecurity+nfs4_label_init_security

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: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4: Sanity check the server reply in _nfs4_server_capabilities

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: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4.2: encode_readdir - only ask for labels when doing readdirplus

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: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs: set security label when revalidating inode

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: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4.2: Fix a mismatch between Linux labeled NFS and the NFSv4.2 spec

In the spec, the security label attribute id is '80', which means that
it should be bit number 80-64 == 16 in the 3rd word of the bitmap.

Fixes: 4488cc96c581: NFS: Add NFSv4.2 protocol constants
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Steve Dickson <steved@redhat.com>
Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Fix a missing initialisation when reading the SELinux label

Ensure that _nfs4_do_get_security_label() also initialises the
SEQUENCE call correctly, by having it call into nfs4_call_sync().

Reported-by: Jeff Layton <jlayton@redhat.com>
Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs: fix oops when trying to set SELinux label

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: Chao Ye <cye@redhat.com>
Cc: David Quigley <dpquigl@davequigley.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs: fix inverted test for delegation in nfs4_reclaim_open_state

commit 6686390bab6a0e0 (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: Jeff Layton <jlayton@redhat.com>
Fixes: 6686390bab6a: NFS: remove incorrect "Lock reclaim failed!" warning.
Cc: stable@vger.kernel.org # 3.12
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Cleanup xs_destroy()

There is no longer any need for a separate xs_local_destroy() helper.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: close a rare race in xs_tcp_setup_socket.

We have one report of a crash in xs_tcp_setup_socket.
The call path to the crash is:

  xs_tcp_setup_socket -> inet_stream_connect -> lock_sock_nested.

The 'sock' passed to that last function is NULL.

The only way I can see this happening is a concurrent call to
xs_close:

  xs_close -> xs_reset_transport -> sock_release -> inet_release

inet_release sets:
   sock->sk = NULL;
inet_stream_connect calls
   lock_sock(sock->sk);
which gets NULL.

All calls to xs_close are protected by XPRT_LOCKED as are most
activations of the workqueue which runs xs_tcp_setup_socket.
The exception is xs_tcp_schedule_linger_timeout.

So presumably the timeout queued by the later fires exactly when some
other code runs xs_close().

To protect against this we can move the cancel_delayed_work_sync()
call from xs_destory() to xs_close().

As xs_close is never called from the worker scheduled on
->connect_worker, this can never deadlock.

Signed-off-by: NeilBrown <neilb@suse.de>
[Trond: Make it safe to call cancel_delayed_work_sync() on AF_LOCAL sockets]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: remove duplicated include from clnt.c

Remove duplicated include.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Merge branch 'fscache' of git://git./linux/kernel/git/dhowells/linux-fs into linux-next

Pull fs-cache fixes from David Howells:

Can you pull these commits to fix an issue with NFS whereby caching can be
enabled on a file that is open for writing by subsequently opening it for
reading.  This can be made to crash by opening it for writing again if you're
quick enough.

The gist of the patchset is that the cookie should be acquired at inode
creation only and subsequently enabled and disabled as appropriate (which
dispenses with the backing objects when they're not needed).

The extra synchronisation that NFS does can then be dispensed with as it is
thenceforth managed by FS-Cache.

Could you send these on to Linus?

This likely will need fixing also in CIFS and 9P also once the FS-Cache
changes are upstream.  AFS and Ceph are probably safe.

* 'fscache' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  NFS: Use i_writecount to control whether to get an fscache cookie in nfs_open()
  FS-Cache: Provide the ability to enable/disable cookies
  FS-Cache: Add use/unuse/wake cookie wrappers

nfs: use IS_ROOT not DCACHE_DISCONNECTED

This check was added by Al Viro with
d9e80b7de91db05c1c4d2e5ebbfd70b3b3ba0e0f "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: J. Bruce Fields <bfields@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Fix buffer overflow checking in gss_encode_v0_msg/gss_encode_v1_msg

In gss_encode_v1_msg, it is pointless to BUG() after the overflow has
happened. Replace the existing sprintf()-based code with scnprintf(),
and warn if an overflow is ever triggered.

In gss_encode_v0_msg, replace the runtime BUG_ON() with an appropriate
compile-time BUILD_BUG_ON.

Reported-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: gss_alloc_msg - choose _either_ a v0 message or a v1 message

Add the missing 'break' to ensure that we don't corrupt a legacy 'v0' type
message by appending the 'v1'.

Cc: Bruce Fields <bfields@fieldses.org>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: remove an unnecessary if statement

If req allocated failed just goto out_free, no need to check the
'i < num_prealloc'. There is just code simplification, no
functional changes.

Signed-off-by: Wang Weidong <wangweidong1@huawei.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs: Use PTR_ERR_OR_ZERO in 'nfs/nfs4super.c'

Use 'PTR_ERR_OR_ZERO()' rather than 'IS_ERR(...) ? PTR_ERR(...) : 0'.

Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs: Use PTR_ERR_OR_ZERO in 'nfs41_callback_up' function

Use 'PTR_ERR_OR_ZERO()' rather than 'IS_ERR(...) ? PTR_ERR(...) : 0'.

Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs: Remove useless 'error' assignment

the 'error' variable was been assigned twice in vain.

Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

sunrpc: comment typo fix

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Add correct rcu_dereference annotation in rpc_clnt_set_transport

rpc_clnt_set_transport should use rcu_derefence_protected(), as it is
only safe to be called with the rpc_clnt::cl_lock held.

Cc: Chuck Lever <Chuck.Lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: add support for multiple sec= mount options

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: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: stop using NFS_MOUNT_SECFLAVOUR server flag

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: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: cache parsed auth_info in nfs_server

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: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: separate passed security flavs from selected

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: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4: make nfs_find_best_sec static

It's not used outside of nfs4namespace.c anymore.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Fix possible endless state recovery wait

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: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Set EXCHGID4_FLAG_SUPP_MOVED_MIGR

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: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Handle SEQ4_STATUS_LEASE_MOVED

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: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Handle NFS4ERR_LEASE_MOVED during async RENEW

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: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Migration support for RELEASE_LOCKOWNER

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: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Implement support for NFS4ERR_LEASE_MOVED

Trigger lease-moved recovery when a request returns
NFS4ERR_LEASE_MOVED.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Support NFS4ERR_LEASE_MOVED recovery in state manager

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: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Add method to detect whether an FSID is still on the server

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: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Handle NFS4ERR_MOVED during delegation recall

When a server returns NFS4ERR_MOVED during a delegation recall,
trigger the new migration recovery logic in the state manager.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Add migration recovery callouts in nfs4proc.c

When a server returns NFS4ERR_MOVED, trigger the new migration
recovery logic in the state manager.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Rename "stateid_invalid" label

I'm going to use this exit label also for migration recovery
failures.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Re-use exit code in nfs4_async_handle_error()

Clean up.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Add basic migration support to state manager thread

Migration recovery and state recovery must be serialized, so handle
both in the state manager thread.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Add a super_block backpointer to the nfs_server struct

NFS_SB() returns the pointer to an nfs_server struct, given a
pointer to a super_block. But we have no way to go back the other
way.

Add a super_block backpointer field so that, given an nfs_server
struct, it is easy to get to the filesystem's root dentry.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Add method to retrieve fs_locations during migration recovery

The nfs4_proc_fs_locations() function is invoked during referral
processing to perform a GETATTR(fs_locations) on an object's parent
directory in order to discover the target of the referral.  It
performs a LOOKUP in the compound, so the client needs to know the
parent's file handle a priori.

Unfortunately this function is not adequate for handling migration
recovery.  We need to probe fs_locations information on an FSID, but
there's no parent directory available for many operations that
can return NFS4ERR_MOVED.

Another subtlety: recovering from NFS4ERR_LEASE_MOVED is a process
of walking over a list of known FSIDs that reside on the server, and
probing whether they have migrated.  Once the server has detected
that the client has probed all migrated file systems, it stops
returning NFS4ERR_LEASE_MOVED.

A minor version zero server needs to know what client ID is
requesting fs_locations information so it can clear the flag that
forces it to continue returning NFS4ERR_LEASE_MOVED.  This flag is
set per client ID and per FSID.  However, the client ID is not an
argument of either the PUTFH or GETATTR operations.  Later minor
versions have client ID information embedded in the compound's
SEQUENCE operation.

Therefore, by convention, minor version zero clients send a RENEW
operation in the same compound as the GETATTR(fs_locations), since
RENEW's one argument is a clientid4.  This allows a minor version
zero server to identify correctly the client that is probing for a
migration.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Export _nfs_display_fhandle()

Allow code in nfsv4.ko to use _nfs_display_fhandle().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Introduce a vector of migration recovery ops

The differences between minor version 0 and minor version 1
migration will be abstracted by the addition of a set of migration
recovery ops.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Add functions to swap transports during migration recovery

Introduce functions that can walk through an array of returned
fs_locations information and connect a transport to one of the
destination servers listed therein.

Note that NFS minor version 1 introduces "fs_locations_info" which
extends the locations array sorting criteria available to clients.
This is not supported yet.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: Add nfs4_update_server

New function nfs4_update_server() moves an nfs_server to a different
nfs_client. This is done as part of migration recovery.

Though it may be appealing to think of them as the same thing,
migration recovery is not the same as following a referral.

For a referral, the client has not descended into the file system
yet: it has no nfs_server, no super block, no inodes or open state.
It is enough to simply instantiate the nfs_server and super block,
and perform a referral mount.

For a migration, however, we have all of those things already, and
they have to be moved to a different nfs_client. No local namespace
changes are needed here.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Add a helper to switch the transport of an rpc_clnt

Add an RPC client API to redirect an rpc_clnt's transport from a
source server to a destination server during a migration event.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
[ cel: forward ported to 3.12 ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Modify synopsis of rpc_client_register()

The rpc_client_register() helper was added in commit e73f4cc0,
"SUNRPC: split client creation routine into setup and registration,"
Mon Jun 24 11:52:52 2013. In a subsequent patch, I'd like to invoke
rpc_client_register() from a context where a struct rpc_create_args
is not available.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4: don't reprocess cached open CLAIM_PREVIOUS

Cached opens have already been handled by _nfs4_opendata_reclaim_to_nfs4_state
and can safely skip being reprocessed, but must still call update_open_stateid
to make sure that all active fmodes are recovered.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Cc: stable@vger.kernel.org # 3.7.x: f494a6071d3: NFSv4: fix NULL dereference
Cc: stable@vger.kernel.org # 3.7.x: a43ec98b72a: NFSv4: don't fail on missin
Cc: stable@vger.kernel.org # 3.7.x
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4: Fix state reference counting in _nfs4_opendata_reclaim_to_nfs4_state

Currently, if the call to nfs_refresh_inode fails, then we end up leaking
a reference count, due to the call to nfs4_get_open_state.
While we're at it, replace nfs4_get_open_state with a simple call to
atomic_inc(); there is no need to do a full lookup of the struct nfs_state
since it is passed as an argument in the struct nfs4_opendata, and
is already assigned to the variable 'state'.

Cc: stable@vger.kernel.org # 3.7.x: a43ec98b72a: NFSv4: don't fail on missing
Cc: stable@vger.kernel.org # 3.7.x
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4: don't fail on missing fattr in open recover

This is an unneeded check that could cause the client to fail to recover
opens.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4: fix NULL dereference in open recover

_nfs4_opendata_reclaim_to_nfs4_state doesn't expect to see a cached
open CLAIM_PREVIOUS, but this can happen. An example is when there are
RDWR openers and RDONLY openers on a delegation stateid. The recovery
path will first try an open CLAIM_PREVIOUS for the RDWR openers, this
marks the delegation as not needing RECLAIM anymore, so the open
CLAIM_PREVIOUS for the RDONLY openers will not actually send an rpc.

The NULL dereference is due to _nfs4_opendata_reclaim_to_nfs4_state
returning PTR_ERR(rpc_status) when !rpc_done. When the open is
cached, rpc_done == 0 and rpc_status == 0, thus
_nfs4_opendata_reclaim_to_nfs4_state returns NULL - this is unexpected
by callers of nfs4_opendata_to_nfs4_state().

This can be reproduced easily by opening the same file two times on an
NFSv4.0 mount with delegations enabled, once as RDWR and once as RDONLY then
sleeping for a long time.  While the files are held open, kick off state
recovery and this NULL dereference will be hit every time.

An example OOPS:

[   65.003602] BUG: unable to handle kernel NULL pointer dereference at 00000000
00000030
[   65.005312] IP: [<ffffffffa037d6ee>] __nfs4_close+0x1e/0x160 [nfsv4]
[   65.006820] PGD 7b0ea067 PUD 791ff067 PMD 0
[   65.008075] Oops: 0000 [#1] SMP
[   65.008802] Modules linked in: rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache
snd_ens1371 gameport nfsd snd_rawmidi snd_ac97_codec ac97_bus btusb snd_seq snd
_seq_device snd_pcm ppdev bluetooth auth_rpcgss coretemp snd_page_alloc crc32_pc
lmul crc32c_intel ghash_clmulni_intel microcode rfkill nfs_acl vmw_balloon serio
_raw snd_timer lockd parport_pc e1000 snd soundcore parport i2c_piix4 shpchp vmw
_vmci sunrpc ata_generic mperf pata_acpi mptspi vmwgfx ttm scsi_transport_spi dr
m mptscsih mptbase i2c_core
[   65.018684] CPU: 0 PID: 473 Comm: 192.168.10.85-m Not tainted 3.11.2-201.fc19
.x86_64 #1
[   65.020113] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop
Reference Platform, BIOS 6.00 07/31/2013
[   65.022012] task: ffff88003707e320 ti: ffff88007b906000 task.ti: ffff88007b906000
[   65.023414] RIP: 0010:[<ffffffffa037d6ee>]  [<ffffffffa037d6ee>] __nfs4_close+0x1e/0x160 [nfsv4]
[   65.025079] RSP: 0018:ffff88007b907d10  EFLAGS: 00010246
[   65.026042] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   65.027321] RDX: 0000000000000050 RSI: 0000000000000001 RDI: 0000000000000000
[   65.028691] RBP: ffff88007b907d38 R08: 0000000000016f60 R09: 0000000000000000
[   65.029990] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[   65.031295] R13: 0000000000000050 R14: 0000000000000000 R15: 0000000000000001
[   65.032527] FS:  0000000000000000(0000) GS:ffff88007f600000(0000) knlGS:0000000000000000
[   65.033981] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   65.035177] CR2: 0000000000000030 CR3: 000000007b27f000 CR4: 00000000000407f0
[   65.036568] Stack:
[   65.037011]  0000000000000000 0000000000000001 ffff88007b907d90 ffff88007a880220
[   65.038472]  ffff88007b768de8 ffff88007b907d48 ffffffffa037e4a5 ffff88007b907d80
[   65.039935]  ffffffffa036a6c8 ffff880037020e40 ffff88007a880000 ffff880037020e40
[   65.041468] Call Trace:
[   65.042050]  [<ffffffffa037e4a5>] nfs4_close_state+0x15/0x20 [nfsv4]
[   65.043209]  [<ffffffffa036a6c8>] nfs4_open_recover_helper+0x148/0x1f0 [nfsv4]
[   65.044529]  [<ffffffffa036a886>] nfs4_open_recover+0x116/0x150 [nfsv4]
[   65.045730]  [<ffffffffa036d98d>] nfs4_open_reclaim+0xad/0x150 [nfsv4]
[   65.046905]  [<ffffffffa037d979>] nfs4_do_reclaim+0x149/0x5f0 [nfsv4]
[   65.048071]  [<ffffffffa037e1dc>] nfs4_run_state_manager+0x3bc/0x670 [nfsv4]
[   65.049436]  [<ffffffffa037de20>] ? nfs4_do_reclaim+0x5f0/0x5f0 [nfsv4]
[   65.050686]  [<ffffffffa037de20>] ? nfs4_do_reclaim+0x5f0/0x5f0 [nfsv4]
[   65.051943]  [<ffffffff81088640>] kthread+0xc0/0xd0
[   65.052831]  [<ffffffff81088580>] ? insert_kthread_work+0x40/0x40
[   65.054697]  [<ffffffff8165686c>] ret_from_fork+0x7c/0xb0
[   65.056396]  [<ffffffff81088580>] ? insert_kthread_work+0x40/0x40
[   65.058208] Code: 5c 41 5d 5d c3 0f 1f 84 00 00 00 00 00 66 66 66 66 90 55 48 89 e5 41 57 41 89 f7 41 56 41 89 ce 41 55 41 89 d5 41 54 53 48 89 fb <4c> 8b 67 30 f0 41 ff 44 24 44 49 8d 7c 24 40 e8 0e 0a 2d e1 44
[   65.065225] RIP  [<ffffffffa037d6ee>] __nfs4_close+0x1e/0x160 [nfsv4]
[   65.067175]  RSP <ffff88007b907d10>
[   65.068570] CR2: 0000000000000030
[   65.070098] ---[ end trace 0d1fe4f5c7dd6f8b ]---

Cc: <stable@vger.kernel.org> #3.7+
Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4.1: Don't change the security label as part of open reclaim.

The current caching model calls for the security label to be set on
first lookup and/or on any subsequent label changes. There is no
need to do it as part of an open reclaim.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs: fix handling of invalid mount options in nfs_remount

nfs_parse_mount_options returns 0 on error, not -errno.

Reported-by: Karel Zak <kzak@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

nfs: reject version and minorversion changes on remount attempts

Reported-by: Eric Doutreleau <edoutreleau@genoscope.cns.fr>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4 Remove zeroing state kern warnings

As of commit 5d422301f97b821301efcdb6fc9d1a83a5c102d6 we no longer zero the
state.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: call_connect_status should recheck bind and connect status on error

Currently, we go directly to call_transmit which sends us to call_status
on error. If we know that the connect attempt failed, we should rather
just jump straight back to call_bind and call_connect.

Ditto for EAGAIN, except do not delay.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Remove redundant initialisations of request rq_bytes_sent

Now that we clear the rq_bytes_sent field on unlock, we don't need
to set it on lock, so we just set it once when initialising the request.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Fix RPC call retransmission statistics

A retransmit should be when you successfully transmit an RPC call to
the server a second time.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4: Ensure that we disable the resend timeout for NFSv4

The spec states that the client should not resend requests because
the server will disconnect if it needs to drop an RPC request.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Add RPC task and client level options to disable the resend timeout

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Clean up - convert xprt_prepare_transmit to return a bool

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Clear the request rq_bytes_sent field in xprt_release_write

Otherwise the tests of req->rq_bytes_sent in xprt_prepare_transmit
will fail if we're dealing with a resend.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Don't set the request connect_cookie until a successful transmit

We're using the request connect_cookie to track whether or not a
request was successfully transmitted on the current transport
connection or not. For that reason we should ensure that it is
only set after we've successfully transmitted the request.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Only update the TCP connect cookie on a successful connect

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Enable the keepalive option for TCP sockets

For NFSv4 we want to avoid retransmitting RPC calls unless the TCP
connection breaks. However we still want to detect TCP connection
breakage as soon as possible. Do this by setting the keepalive option
with the idle timeout and count set to the 'timeo' and 'retrans' mount
options.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4: Fix a use-after-free situation in _nfs4_proc_getlk()

In nfs4_proc_getlk(), when some error causes a retry of the call to
_nfs4_proc_getlk(), we can end up with Oopses of the form

BUG: unable to handle kernel NULL pointer dereference at 0000000000000134
IP: [<ffffffff8165270e>] _raw_spin_lock+0xe/0x30
<snip>
Call Trace:
  [<ffffffff812f287d>] _atomic_dec_and_lock+0x4d/0x70
  [<ffffffffa053c4f2>] nfs4_put_lock_state+0x32/0xb0 [nfsv4]
  [<ffffffffa053c585>] nfs4_fl_release_lock+0x15/0x20 [nfsv4]
  [<ffffffffa0522c06>] _nfs4_proc_getlk.isra.40+0x146/0x170 [nfsv4]
  [<ffffffffa052ad99>] nfs4_proc_lock+0x399/0x5a0 [nfsv4]

The problem is that we don't clear the request->fl_ops after the first
try and so when we retry, nfs4_set_lock_state() exits early without
setting the lock stateid.
Regression introduced by commit 70cc6487a4e08b8698c0e2ec935fb48d10490162
(locks: make ->lock release private data before returning in GETLK case)

Reported-by: Weston Andros Adamson <dros@netapp.com>
Reported-by: Jorge Mora <mora@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: <stable@vger.kernel.org> #2.6.22+

Merge tag 'nfs-for-3.12-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client bugfixes from Trond Myklebust:
- Stable fix for Oopses in the pNFS files layout driver
- Fix a regression when doing a non-exclusive file create on NFSv4.x
- NFSv4.1 security negotiation fixes when looking up the root
   filesystem
- Fix a memory ordering issue in the pNFS files layout driver

* tag 'nfs-for-3.12-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFS: Give "flavor" an initial value to fix a compile warning
  NFSv4.1: try SECINFO_NO_NAME flavs until one works
  NFSv4.1: Ensure memory ordering between nfs4_ds_connect and nfs4_fl_prepare_ds
  NFSv4.1: nfs4_fl_prepare_ds - fix bugs when the connect attempt fails
  NFSv4: Honour the 'opened' parameter in the atomic_open() filesystem method

Merge branch 'akpm' (fixes from Andrew Morton)

Merge misc fixes from Andrew Morton.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (22 commits)
  pidns: fix free_pid() to handle the first fork failure
  ipc,msg: prevent race with rmid in msgsnd,msgrcv
  ipc/sem.c: update sem_otime for all operations
  mm/hwpoison: fix the lack of one reference count against poisoned page
  mm/hwpoison: fix false report on 2nd attempt at page recovery
  mm/hwpoison: fix test for a transparent huge page
  mm/hwpoison: fix traversal of hugetlbfs pages to avoid printk flood
  block: change config option name for cmdline partition parsing
  mm/mlock.c: prevent walking off the end of a pagetable in no-pmd configuration
  mm: avoid reinserting isolated balloon pages into LRU lists
  arch/parisc/mm/fault.c: fix uninitialized variable usage
  include/asm-generic/vtime.h: avoid zero-length file
  nilfs2: fix issue with race condition of competition between segments for dirty blocks
  Documentation/kernel-parameters.txt: replace kernelcore with Movable
  mm/bounce.c: fix a regression where MS_SNAP_STABLE (stable pages snapshotting) was ignored
  kernel/kmod.c: check for NULL in call_usermodehelper_exec()
  ipc/sem.c: synchronize the proc interface
  ipc/sem.c: optimize sem_lock()
  ipc/sem.c: fix race in sem_lock()
  mm/compaction.c: periodically schedule when freeing pages
  ...

pidns: fix free_pid() to handle the first fork failure

"case 0" in free_pid() assumes that disable_pid_allocation() should
clear PIDNS_HASH_ADDING before the last pid goes away.

However this doesn't happen if the first fork() fails to create the
child reaper which should call disable_pid_allocation().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc,msg: prevent race with rmid in msgsnd,msgrcv

This fixes a race in both msgrcv() and msgsnd() between finding the msg
and actually dealing with the queue, as another thread can delete shmid
underneath us if we are preempted before acquiring the
kern_ipc_perm.lock.

Manfred illustrates this nicely:

Assume a preemptible kernel that is preempted just after

    msq = msq_obtain_object_check(ns, msqid)

in do_msgrcv().  The only lock that is held is rcu_read_lock().

Now the other thread processes IPC_RMID.  When the first task is
resumed, then it will happily wait for messages on a deleted queue.

Fix this by checking for if the queue has been deleted after taking the
lock.

Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Reported-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: <stable@vger.kernel.org> [3.11]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc/sem.c: update sem_otime for all operations

In commit 0a2b9d4c7967 ("ipc/sem.c: move wake_up_process out of the
spinlock section"), the update of semaphore's sem_otime(last semop time)
was moved to one central position (do_smart_update).

But since do_smart_update() is only called for operations that modify
the array, this means that wait-for-zero semops do not update sem_otime
anymore.

The fix is simple:
Non-alter operations must update sem_otime.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Reported-by: Jia He <jiakernel@gmail.com>
Tested-by: Jia He <jiakernel@gmail.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hwpoison: fix the lack of one reference count against poisoned page

The lack of one reference count against poisoned page for hwpoison_inject
w/o hwpoison_filter enabled result in hwpoison detect -1 users still
referenced the page, however, the number should be 0 except the poison
handler held one after successfully unmap.  This patch fix it by hold one
referenced count against poisoned page for hwpoison_inject w/ and w/o
hwpoison_filter enabled.

Before patch:

[   71.902112] Injecting memory failure at pfn 224706
[   71.902137] MCE 0x224706: dirty LRU page recovery: Failed
[   71.902138] MCE 0x224706: dirty LRU page still referenced by -1 users

After patch:

[   94.710860] Injecting memory failure at pfn 215b68
[   94.710885] MCE 0x215b68: dirty LRU page recovery: Recovered

Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hwpoison: fix false report on 2nd attempt at page recovery

If the page is poisoned by software injection w/ MF_COUNT_INCREASED
flag, there is a false report during the 2nd attempt at page recovery
which is not truthful.

This patch fixes it by reporting the first attempt to try free buddy
page recovery if MF_COUNT_INCREASED is set.

Before patch:

[  346.332041] Injecting memory failure at pfn 200010
[  346.332189] MCE 0x200010: free buddy, 2nd try page recovery: Delayed

After patch:

[  297.742600] Injecting memory failure at pfn 200010
[  297.742941] MCE 0x200010: free buddy page recovery: Delayed

Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hwpoison: fix test for a transparent huge page

PageTransHuge() can't guarantee the page is a transparent huge page
since it returns true for both transparent huge and hugetlbfs pages.

This patch fixes it by checking the page is also !hugetlbfs page.

Before patch:

[  121.571128] Injecting memory failure at pfn 23a200
[  121.571141] MCE 0x23a200: huge page recovery: Delayed
[  140.355100] MCE: Memory failure is now running on 0x23a200

After patch:

[   94.290793] Injecting memory failure at pfn 23a000
[   94.290800] MCE 0x23a000: huge page recovery: Delayed
[  105.722303] MCE: Software-unpoisoned page 0x23a000

Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hwpoison: fix traversal of hugetlbfs pages to avoid printk flood

madvise_hwpoison won't check if the page is small page or huge page and
traverses in small page granularity against the range unconditionally,
which result in a printk flood "MCE xxx: already hardware poisoned" if
the page is a huge page.

This patch fixes it by using compound_order(compound_head(page)) for
huge page iterator.

Testcase:

#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <errno.h>

#define PAGES_TO_TEST 3
#define PAGE_SIZE 4096 * 512

int main(void)
{
char *mem;
int i;

mem = mmap(NULL, PAGES_TO_TEST * PAGE_SIZE,
PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, 0, 0);

if (madvise(mem, PAGES_TO_TEST * PAGE_SIZE, MADV_HWPOISON) == -1)
return -1;

munmap(mem, PAGES_TO_TEST * PAGE_SIZE);

return 0;
}

Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

block: change config option name for cmdline partition parsing

Recently commit bab55417b10c ("block: support embedded device command
line partition") introduced CONFIG_CMDLINE_PARSER. However, that name
is too generic and sounds like it enables/disables generic kernel boot
arg processing, when it really is block specific.

Before this option becomes a part of a full/final release, add the BLK_
prefix to it so that it is clear in absence of any other context that it
is block specific.

In addition, fix up the following less critical items:
- help text was not really at all helpful.
- index file for Documentation was not updated
- add the new arg to Documentation/kernel-parameters.txt
- clarify wording in source comments

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Cai Zhiyong <caizhiyong@huawei.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/mlock.c: prevent walking off the end of a pagetable in no-pmd configuration

The function __munlock_pagevec_fill() introduced in commit 7a8010cd3627
("mm: munlock: manual pte walk in fast path instead of
follow_page_mask()") uses pmd_addr_end() for restricting its operation
within current page table.

This is insufficient on architectures/configurations where pmd is folded
and pmd_addr_end() just returns the end of the full range to be walked.
In this case, it allows pte++ to walk off the end of a page table
resulting in unpredictable behaviour.

This patch fixes the function by using pgd_addr_end() and pud_addr_end()
before pmd_addr_end(), which will yield correct page table boundary on
all configurations. This is similar to what existing page walkers do
when walking each level of the page table.

Additionaly, the patch clarifies a comment for get_locked_pte() call in the
function.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Cc: Jörn Engel <joern@logfs.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: avoid reinserting isolated balloon pages into LRU lists

Isolated balloon pages can wrongly end up in LRU lists when
migrate_pages() finishes its round without draining all the isolated
page list.

The same issue can happen when reclaim_clean_pages_from_list() tries to
reclaim pages from an isolated page list, before migration, in the CMA
path.  Such balloon page leak opens a race window against LRU lists
shrinkers that leads us to the following kernel panic:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
  IP: [<ffffffff810c2625>] shrink_page_list+0x24e/0x897
  PGD 3cda2067 PUD 3d713067 PMD 0
  Oops: 0000 [#1] SMP
  CPU: 0 PID: 340 Comm: kswapd0 Not tainted 3.12.0-rc1-22626-g4367597 #87
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  RIP: shrink_page_list+0x24e/0x897
  RSP: 0000:ffff88003da499b8  EFLAGS: 00010286
  RAX: 0000000000000000 RBX: ffff88003e82bd60 RCX: 00000000000657d5
  RDX: 0000000000000000 RSI: 000000000000031f RDI: ffff88003e82bd40
  RBP: ffff88003da49ab0 R08: 0000000000000001 R09: 0000000081121a45
  R10: ffffffff81121a45 R11: ffff88003c4a9a28 R12: ffff88003e82bd40
  R13: ffff88003da0e800 R14: 0000000000000001 R15: ffff88003da49d58
  FS:  0000000000000000(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000067d9000 CR3: 000000003ace5000 CR4: 00000000000407b0
  Call Trace:
    shrink_inactive_list+0x240/0x3de
    shrink_lruvec+0x3e0/0x566
    __shrink_zone+0x94/0x178
    shrink_zone+0x3a/0x82
    balance_pgdat+0x32a/0x4c2
    kswapd+0x2f0/0x372
    kthread+0xa2/0xaa
    ret_from_fork+0x7c/0xb0
  Code: 80 7d 8f 01 48 83 95 68 ff ff ff 00 4c 89 e7 e8 5a 7b 00 00 48 85 c0 49 89 c5 75 08 80 7d 8f 00 74 3e eb 31 48 8b 80 18 01 00 00 <48> 8b 74 0d 48 8b 78 30 be 02 00 00 00 ff d2 eb
  RIP  [<ffffffff810c2625>] shrink_page_list+0x24e/0x897
   RSP <ffff88003da499b8>
  CR2: 0000000000000028
  ---[ end trace 703d2451af6ffbfd ]---
  Kernel panic - not syncing: Fatal exception

This patch fixes the issue, by assuring the proper tests are made at
putback_movable_pages() & reclaim_clean_pages_from_list() to avoid
isolated balloon pages being wrongly reinserted in LRU lists.

[akpm@linux-foundation.org: clarify awkward comment text]
Signed-off-by: Rafael Aquini <aquini@redhat.com>
Reported-by: Luiz Capitulino <lcapitulino@redhat.com>
Tested-by: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/parisc/mm/fault.c: fix uninitialized variable usage

The FAULT_FLAG_WRITE flag has been set based on uninitialized variable.

Fixes a regression added by commit 759496ba6407 ("arch: mm: pass
userspace fault flag to generic fault handler")

Signed-off-by: Felipe Pena <felipensp@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-generic/vtime.h: avoid zero-length file

patch(1) can't handle zero-length files - it appears to simply not create
the file, so my powerpc build fails.

Put something in here to make life easier.

Cc: Hugh Dickins <hughd@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nilfs2: fix issue with race condition of competition between segments for dirty blocks

Many NILFS2 users were reported about strange file system corruption
(for example):

   NILFS: bad btree node (blocknr=185027): level = 0, flags = 0x0, nchildren = 768
   NILFS error (device sda4): nilfs_bmap_last_key: broken bmap (inode number=11540)

But such error messages are consequence of file system's issue that takes
place more earlier.  Fortunately, Jerome Poulin <jeromepoulin@gmail.com>
and Anton Eliasson <devel@antoneliasson.se> were reported about another
issue not so recently.  These reports describe the issue with segctor
thread's crash:

  BUG: unable to handle kernel paging request at 0000000000004c83
  IP: nilfs_end_page_io+0x12/0xd0 [nilfs2]

  Call Trace:
   nilfs_segctor_do_construct+0xf25/0x1b20 [nilfs2]
   nilfs_segctor_construct+0x17b/0x290 [nilfs2]
   nilfs_segctor_thread+0x122/0x3b0 [nilfs2]
   kthread+0xc0/0xd0
   ret_from_fork+0x7c/0xb0

These two issues have one reason.  This reason can raise third issue
too.  Third issue results in hanging of segctor thread with eating of
100% CPU.

REPRODUCING PATH:

One of the possible way or the issue reproducing was described by
Jermoe me Poulin <jeromepoulin@gmail.com>:

1. init S to get to single user mode.
2. sysrq+E to make sure only my shell is running
3. start network-manager to get my wifi connection up
4. login as root and launch "screen"
5. cd /boot/log/nilfs which is a ext3 mount point and can log when NILFS dies.
6. lscp | xz -9e > lscp.txt.xz
7. mount my snapshot using mount -o cp=3360839,ro /dev/vgUbuntu/root /mnt/nilfs
8. start a screen to dump /proc/kmsg to text file since rsyslog is killed
9. start a screen and launch strace -f -o find-cat.log -t find
/mnt/nilfs -type f -exec cat {} > /dev/null \;
10. start a screen and launch strace -f -o apt-get.log -t apt-get update
11. launch the last command again as it did not crash the first time
12. apt-get crashes
13. ps aux > ps-aux-crashed.log
13. sysrq+W
14. sysrq+E  wait for everything to terminate
15. sysrq+SUSB

Simplified way of the issue reproducing is starting kernel compilation
task and "apt-get update" in parallel.

REPRODUCIBILITY:

The issue is reproduced not stable [60% - 80%].  It is very important to
have proper environment for the issue reproducing.  The critical
conditions for successful reproducing:

(1) It should have big modified file by mmap() way.

(2) This file should have the count of dirty blocks are greater that
    several segments in size (for example, two or three) from time to time
    during processing.

(3) It should be intensive background activity of files modification
    in another thread.

INVESTIGATION:

First of all, it is possible to see that the reason of crash is not valid
page address:

  NILFS [nilfs_segctor_complete_write]:2100 bh->b_count 0, bh->b_blocknr 13895680, bh->b_size 13897727, bh->b_page 0000000000001a82
  NILFS [nilfs_segctor_complete_write]:2101 segbuf->sb_segnum 6783

Moreover, value of b_page (0x1a82) is 6786.  This value looks like segment
number.  And b_blocknr with b_size values look like block numbers.  So,
buffer_head's pointer points on not proper address value.

Detailed investigation of the issue is discovered such picture:

  [-----------------------------SEGMENT 6783-------------------------------]
  NILFS [nilfs_segctor_do_construct]:2310 nilfs_segctor_begin_construction
  NILFS [nilfs_segctor_do_construct]:2321 nilfs_segctor_collect
  NILFS [nilfs_segctor_do_construct]:2336 nilfs_segctor_assign
  NILFS [nilfs_segctor_do_construct]:2367 nilfs_segctor_update_segusage
  NILFS [nilfs_segctor_do_construct]:2371 nilfs_segctor_prepare_write
  NILFS [nilfs_segctor_do_construct]:2376 nilfs_add_checksums_on_logs
  NILFS [nilfs_segctor_do_construct]:2381 nilfs_segctor_write
  NILFS [nilfs_segbuf_submit_bio]:464 bio->bi_sector 111149024, segbuf->sb_segnum 6783

  [-----------------------------SEGMENT 6784-------------------------------]
  NILFS [nilfs_segctor_do_construct]:2310 nilfs_segctor_begin_construction
  NILFS [nilfs_segctor_do_construct]:2321 nilfs_segctor_collect
  NILFS [nilfs_lookup_dirty_data_buffers]:782 bh->b_count 1, bh->b_page ffffea000709b000, page->index 0, i_ino 1033103, i_size 25165824
  NILFS [nilfs_lookup_dirty_data_buffers]:783 bh->b_assoc_buffers.next ffff8802174a6798, bh->b_assoc_buffers.prev ffff880221cffee8
  NILFS [nilfs_segctor_do_construct]:2336 nilfs_segctor_assign
  NILFS [nilfs_segctor_do_construct]:2367 nilfs_segctor_update_segusage
  NILFS [nilfs_segctor_do_construct]:2371 nilfs_segctor_prepare_write
  NILFS [nilfs_segctor_do_construct]:2376 nilfs_add_checksums_on_logs
  NILFS [nilfs_segctor_do_construct]:2381 nilfs_segctor_write
  NILFS [nilfs_segbuf_submit_bh]:575 bh->b_count 1, bh->b_page ffffea000709b000, page->index 0, i_ino 1033103, i_size 25165824
  NILFS [nilfs_segbuf_submit_bh]:576 segbuf->sb_segnum 6784
  NILFS [nilfs_segbuf_submit_bh]:577 bh->b_assoc_buffers.next ffff880218a0d5f8, bh->b_assoc_buffers.prev ffff880218bcdf50
  NILFS [nilfs_segbuf_submit_bio]:464 bio->bi_sector 111150080, segbuf->sb_segnum 6784, segbuf->sb_nbio 0
  [----------] ditto
  NILFS [nilfs_segbuf_submit_bio]:464 bio->bi_sector 111164416, segbuf->sb_segnum 6784, segbuf->sb_nbio 15

  [-----------------------------SEGMENT 6785-------------------------------]
  NILFS [nilfs_segctor_do_construct]:2310 nilfs_segctor_begin_construction
  NILFS [nilfs_segctor_do_construct]:2321 nilfs_segctor_collect
  NILFS [nilfs_lookup_dirty_data_buffers]:782 bh->b_count 2, bh->b_page ffffea000709b000, page->index 0, i_ino 1033103, i_size 25165824
  NILFS [nilfs_lookup_dirty_data_buffers]:783 bh->b_assoc_buffers.next ffff880219277e80, bh->b_assoc_buffers.prev ffff880221cffc88
  NILFS [nilfs_segctor_do_construct]:2367 nilfs_segctor_update_segusage
  NILFS [nilfs_segctor_do_construct]:2371 nilfs_segctor_prepare_write
  NILFS [nilfs_segctor_do_construct]:2376 nilfs_add_checksums_on_logs
  NILFS [nilfs_segctor_do_construct]:2381 nilfs_segctor_write
  NILFS [nilfs_segbuf_submit_bh]:575 bh->b_count 2, bh->b_page ffffea000709b000, page->index 0, i_ino 1033103, i_size 25165824
  NILFS [nilfs_segbuf_submit_bh]:576 segbuf->sb_segnum 6785
  NILFS [nilfs_segbuf_submit_bh]:577 bh->b_assoc_buffers.next ffff880218a0d5f8, bh->b_assoc_buffers.prev ffff880222cc7ee8
  NILFS [nilfs_segbuf_submit_bio]:464 bio->bi_sector 111165440, segbuf->sb_segnum 6785, segbuf->sb_nbio 0
  [----------] ditto
  NILFS [nilfs_segbuf_submit_bio]:464 bio->bi_sector 111177728, segbuf->sb_segnum 6785, segbuf->sb_nbio 12

  NILFS [nilfs_segctor_do_construct]:2399 nilfs_segctor_wait
  NILFS [nilfs_segbuf_wait]:676 segbuf->sb_segnum 6783
  NILFS [nilfs_segbuf_wait]:676 segbuf->sb_segnum 6784
  NILFS [nilfs_segbuf_wait]:676 segbuf->sb_segnum 6785

  NILFS [nilfs_segctor_complete_write]:2100 bh->b_count 0, bh->b_blocknr 13895680, bh->b_size 13897727, bh->b_page 0000000000001a82

  BUG: unable to handle kernel paging request at 0000000000001a82
  IP: [<ffffffffa024d0f2>] nilfs_end_page_io+0x12/0xd0 [nilfs2]

Usually, for every segment we collect dirty files in list.  Then, dirty
blocks are gathered for every dirty file, prepared for write and
submitted by means of nilfs_segbuf_submit_bh() call.  Finally, it takes
place complete write phase after calling nilfs_end_bio_write() on the
block layer.  Buffers/pages are marked as not dirty on final phase and
processed files removed from the list of dirty files.

It is possible to see that we had three prepare_write and submit_bio
phases before segbuf_wait and complete_write phase.  Moreover, segments
compete between each other for dirty blocks because on every iteration
of segments processing dirty buffer_heads are added in several lists of
payload_buffers:

  [SEGMENT 6784]: bh->b_assoc_buffers.next ffff880218a0d5f8, bh->b_assoc_buffers.prev ffff880218bcdf50
  [SEGMENT 6785]: bh->b_assoc_buffers.next ffff880218a0d5f8, bh->b_assoc_buffers.prev ffff880222cc7ee8

The next pointer is the same but prev pointer has changed.  It means
that buffer_head has next pointer from one list but prev pointer from
another.  Such modification can be made several times.  And, finally, it
can be resulted in various issues: (1) segctor hanging, (2) segctor
crashing, (3) file system metadata corruption.

FIX:
This patch adds:

(1) setting of BH_Async_Write flag in nilfs_segctor_prepare_write()
    for every proccessed dirty block;

(2) checking of BH_Async_Write flag in
    nilfs_lookup_dirty_data_buffers() and
    nilfs_lookup_dirty_node_buffers();

(3) clearing of BH_Async_Write flag in nilfs_segctor_complete_write(),
    nilfs_abort_logs(), nilfs_forget_buffer(), nilfs_clear_dirty_page().

Reported-by: Jerome Poulin <jeromepoulin@gmail.com>
Reported-by: Anton Eliasson <devel@antoneliasson.se>
Cc: Paul Fertser <fercerpav@gmail.com>
Cc: ARAI Shun-ichi <hermes@ceres.dti.ne.jp>
Cc: Piotr Szymaniak <szarpaj@grubelek.pl>
Cc: Juan Barry Manuel Canham <Linux@riotingpacifist.net>
Cc: Zahid Chowdhury <zahid.chowdhury@starsolutions.com>
Cc: Elmer Zhang <freeboy6716@gmail.com>
Cc: Kenneth Langga <klangga@gmail.com>
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/kernel-parameters.txt: replace kernelcore with Movable

Han Pingtian found a typo in Documentation/kernel-parameters.txt about
"kernelcore=", that "kernelcore" should be replaced with "Movable" here.

Signed-off-by: Weiping Pan <wpan@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/bounce.c: fix a regression where MS_SNAP_STABLE (stable pages snapshotting) was ignored

The "force" parameter in __blk_queue_bounce was being ignored, which
means that stable page snapshots are not always happening (on ext3).
This of course leads to DIF disks reporting checksum errors, so fix this
regression.

The regression was introduced in commit 6bc454d15004 ("bounce: Refactor
__blk_queue_bounce to not use bi_io_vec")

Reported-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: <stable@vger.kernel.org> [3.10+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/kmod.c: check for NULL in call_usermodehelper_exec()

If /proc/sys/kernel/core_pattern contains only "|", a NULL pointer
dereference happens upon core dump because argv_split("") returns
argv[0] == NULL.

This bug was once fixed by commit 264b83c07a84 ("usermodehelper: check
subprocess_info->path != NULL") but was by error reintroduced by commit
7f57cfa4e2aa ("usermodehelper: kill the sub_info->path[0] check").

This bug seems to exist since 2.6.19 (the version which core dump to
pipe was added). Depending on kernel version and config, some side
effect might happen immediately after this oops (e.g. kernel panic with
2.6.32-358.18.1.el6).

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc/sem.c: synchronize the proc interface

The proc interface is not aware of sem_lock(), it instead calls
ipc_lock_object() directly. This means that simple semop() operations
can run in parallel with the proc interface. Right now, this is
uncritical, because the implementation doesn't do anything that requires
a proper synchronization.

But it is dangerous and therefore should be fixed.

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc/sem.c: optimize sem_lock()

Operations that need access to the whole array must guarantee that there
are no simple operations ongoing. Right now this is achieved by
spin_unlock_wait(sem->lock) on all semaphores.

If complex_count is nonzero, then this spin_unlock_wait() is not
necessary, because it was already performed in the past by the thread
that increased complex_count and even though sem_perm.lock was dropped
inbetween, no simple operation could have started, because simple
operations cannot start when complex_count is non-zero.

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Mike Galbraith <bitbucket@online.de>
Cc: Rik van Riel <riel@redhat.com>
Reviewed-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc/sem.c: fix race in sem_lock()

The exclusion of complex operations in sem_lock() is insufficient: after
acquiring the per-semaphore lock, a simple op must first check that
sem_perm.lock is not locked and only after that test check
complex_count.  The current code does it the other way around - and that
creates a race.  Details are below.

The patch is a complete rewrite of sem_lock(), based in part on the code
from Mike Galbraith.  It removes all gotos and all loops and thus the
risk of livelocks.

I have tested the patch (together with the next one) on my i3 laptop and
it didn't cause any problems.

The bug is probably also present in 3.10 and 3.11, but for these kernels
it might be simpler just to move the test of sma->complex_count after
the spin_is_locked() test.

Details of the bug:

Assume:
- sma->complex_count = 0.
- Thread 1: semtimedop(complex op that must sleep)
- Thread 2: semtimedop(simple op).

Pseudo-Trace:

Thread 1: sem_lock(): acquire sem_perm.lock
Thread 1: sem_lock(): check for ongoing simple ops
Nothing ongoing, thread 2 is still before sem_lock().
Thread 1: try_atomic_semop()
<<< preempted.

Thread 2: sem_lock():
        static inline int sem_lock(struct sem_array *sma, struct sembuf *sops,
                                      int nsops)
        {
                int locknum;
         again:
                if (nsops == 1 && !sma->complex_count) {
                        struct sem *sem = sma->sem_base + sops->sem_num;

                        /* Lock just the semaphore we are interested in. */
                        spin_lock(&sem->lock);

                        /*
                         * If sma->complex_count was set while we were spinning,
                         * we may need to look at things we did not lock here.
                         */
                        if (unlikely(sma->complex_count)) {
                                spin_unlock(&sem->lock);
                                goto lock_array;
                        }
        <<<<<<<<<
<<< complex_count is still 0.
<<<
        <<< Here it is preempted
        <<<<<<<<<

Thread 1: try_atomic_semop() returns, notices that it must sleep.
Thread 1: increases sma->complex_count.
Thread 1: drops sem_perm.lock
Thread 2:
                /*
                 * Another process is holding the global lock on the
                 * sem_array; we cannot enter our critical section,
                 * but have to wait for the global lock to be released.
                 */
                if (unlikely(spin_is_locked(&sma->sem_perm.lock))) {
                        spin_unlock(&sem->lock);
                        spin_unlock_wait(&sma->sem_perm.lock);
                        goto again;
                }
<<< sem_perm.lock already dropped, thus no "goto again;"

                locknum = sops->sem_num;

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Mike Galbraith <bitbucket@online.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: <stable@vger.kernel.org> [3.10+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/compaction.c: periodically schedule when freeing pages

We've been getting warnings about an excessive amount of time spent
allocating pages for migration during memory compaction without
scheduling. isolate_freepages_block() already periodically checks for
contended locks or the need to schedule, but isolate_freepages() never
does.

When a zone is massively long and no suitable targets can be found, this
iteration can be quite expensive without ever doing cond_resched().

Check periodically for the need to reschedule while the compaction free
scanner iterates.

Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/binfmt_elf.c: prevent a coredump with a large vm_map_count from Oopsing

A high setting of max_map_count, and a process core-dumping with a large
enough vm_map_count could result in an NT_FILE note not being written,
and the kernel crashing immediately later because it has assumed
otherwise.

Reproduction of the oops-causing bug described here:

https://lkml.org/lkml/2013/8/30/50

Rge ussue originated in commit 2aa362c49c31 ("coredump: extend core dump
note section to contain file names of mapped file") from Oct 4, 2012.

This patch make that section optional in that case. fill_files_note()
should signify the error, and also let the info struct in
elf_core_dump() be zero-initialized so that we can check for the
optionally written note.

[akpm@linux-foundation.org: avoid abusing E2BIG, remove a couple of not-really-needed local variables]
[akpm@linux-foundation.org: fix sparse warning]
Signed-off-by: Dan Aloni <alonid@stratoscale.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Reported-by: Martin MOKREJS <mmokrejs@gmail.com>
Tested-by: Martin MOKREJS <mmokrejs@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>