idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated.  Drop reference to idr_remove_all().  Note that the code
wasn't completely correct before because idr_remove() on all entries
doesn't necessarily release all idr_layers which could lead to memory
leak.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The following set of operations on a NFS client and server will cause

    server# mkdir a
    client# cd a
    server# mv a a.bak
    client# sleep 30  # (or whatever the dir attrcache timeout is)
    client# stat .
    stat: cannot stat `.': Stale NFS file handle

Obviously, we should not be getting an ESTALE error back there since the
inode still exists on the server. The problem is that the lookup code
will call d_revalidate on the dentry that "." refers to, because NFS has
FS_REVAL_DOT set.

nfs_lookup_revalidate will see that the parent directory has changed and
will try to reverify the dentry by redoing a LOOKUP. That of course
fails, so the lookup code returns ESTALE.

The problem here is that d_revalidate is really a bad fit for this case.
What we really want to know at this point is whether the inode is still
good or not, but we don't really care what name it goes by or whether
the dcache is still valid.

Add a new d_op->d_weak_revalidate operation and have complete_walk call
that instead of d_revalidate. The intent there is to allow for a
"weaker" d_revalidate that just checks to see whether the inode is still
good. This is also gives us an opportunity to kill off the FS_REVAL_DOT
special casing.

[AV: changed method name, added note in porting, fixed confusion re
having it possibly called from RCU mode (it won't be)]

Cc: NeilBrown <neilb@suse.de>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

now pnfs client uses block layout, maybe we can remove
blocklayoutdriver first. if we umount later,
it can cause oops in unset_pnfs_layoutdriver.
because nfss->pnfs_curr_ld->clear_layoutdriver is invalid.

reproduce it:
 modprobe  blocklayoutdriver
 mount -t nfs4 -o minorversion=1 pnfsip:/ /mnt/
 rmmod blocklayoutdriver
 umount /mnt

then you can see following

CPU 0
Pid: 17023, comm: umount.nfs4 Tainted: GF          O 3.7.0-rc6-pnfs #1 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform
RIP: 0010:[<ffffffffa04cfe6d>]  [<ffffffffa04cfe6d>] unset_pnfs_layoutdriver+0x1d/0x70 [nfsv4]
RSP: 0018:ffff8800022d9e48  EFLAGS: 00010286
RAX: ffffffffa04a1b00 RBX: ffff88000b013800 RCX: 0000000000000001
RDX: ffffffff81ae8ee0 RSI: ffff880001ee94b8 RDI: ffff88000b013800
RBP: ffff8800022d9e58 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff880001ee9400
R13: ffff8800105978c0 R14: 00007fff25846c08 R15: 0000000001bba550
FS:  00007f45ae7f0700(0000) GS:ffff880012c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: ffffffffa04a1b38 CR3: 0000000002c0c000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process umount.nfs4 (pid: 17023, threadinfo ffff8800022d8000, task ffff880006e48aa0)
Stack:
ffff8800105978c0 ffff88000b013800 ffff8800022d9e78 ffffffffa04cd0ce
ffff8800022d9e78 ffff88000b013800 ffff8800022d9ea8 ffffffffa04755a7
ffff8800022d9ea8 ffff880002f96400 ffff88000b013800 ffff880002f96400
Call Trace:
[<ffffffffa04cd0ce>] nfs4_destroy_server+0x1e/0x30 [nfsv4]
[<ffffffffa04755a7>] nfs_free_server+0xb7/0x150 [nfs]
[<ffffffffa047d4d5>] nfs_kill_super+0x35/0x40 [nfs]
[<ffffffff81178d35>] deactivate_locked_super+0x45/0x70
[<ffffffff8117986a>] deactivate_super+0x4a/0x70
[<ffffffff81193ee2>] mntput_no_expire+0xd2/0x130
[<ffffffff81194d62>] sys_umount+0x72/0xe0
[<ffffffff8154af59>] system_call_fastpath+0x16/0x1b
Code: 06 e1 b8 ea ff ff ff eb 9e 0f 1f 44 00 00 55 48 89 e5 53 48 83 ec 08 66 66 66 66 90 48 8b 87 80 03 00 00 48 89 fb 48 85 c0 74 29 <48> 8b 40 38 48 85 c0 74 02 ff d0 48 8b 03 3e ff 48 04 0f 94 c2
RIP  [<ffffffffa04cfe6d>] unset_pnfs_layoutdriver+0x1d/0x70 [nfsv4]
RSP <ffff8800022d9e48>
CR2: ffffffffa04a1b38
---[ end trace 29f75aaedda058bf ]---

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

smatch analysis:

fs/nfs/getroot.c:130 nfs_get_root() info: redundant null
 check on name calling kfree()

fs/nfs/unlink.c:272 nfs_async_unlink() info: redundant null
 check on devname_garbage calling kfree()

Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: linux-nfs@vger.kernel.org
Signed-off-by: NTim Gardner <tim.gardner@canonical.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

layoutget's prepare hook can call rpc_exit with status = NFS4_OK (0).
Because of this, nfs4_proc_layoutget can't depend on a 0 status to mean
that the RPC was successfully sent, received and parsed.

To fix this, use the result's len member to see if parsing took place.

This fixes the following OOPS -- calling xdr_init_decode() with a buffer length
0 doesn't set the stream's 'p' member and ends up using uninitialized memory
in filelayout_decode_layout.

BUG: unable to handle kernel paging request at 0000000000008050
IP: [<ffffffff81282e78>] memcpy+0x18/0x120
PGD 0
Oops: 0000 [#1] SMP
last sysfs file: /sys/devices/pci0000:00/0000:00:11.0/0000:02:01.0/irq
CPU 1
Modules linked in: nfs_layout_nfsv41_files nfs lockd fscache auth_rpcgss nfs_acl autofs4 sunrpc ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables ipv6 dm_mirror dm_region_hash dm_log dm_mod ppdev parport_pc parport snd_ens1371 snd_rawmidi snd_ac97_codec ac97_bus snd_seq snd_seq_device snd_pcm snd_timer snd soundcore snd_page_alloc e1000 microcode vmware_balloon i2c_piix4 i2c_core sg shpchp ext4 mbcache jbd2 sr_mod cdrom sd_mod crc_t10dif pata_acpi ata_generic ata_piix mptspi mptscsih mptbase scsi_transport_spi [last unloaded: speedstep_lib]

Pid: 1665, comm: flush-0:22 Not tainted 2.6.32-356-test-2 #2 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform
RIP: 0010:[<ffffffff81282e78>]  [<ffffffff81282e78>] memcpy+0x18/0x120
RSP: 0018:ffff88003dfab588  EFLAGS: 00010206
RAX: ffff88003dc42000 RBX: ffff88003dfab610 RCX: 0000000000000009
RDX: 000000003f807ff0 RSI: 0000000000008050 RDI: ffff88003dc42000
RBP: ffff88003dfab5b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000080 R12: 0000000000000024
R13: ffff88003dc42000 R14: ffff88003f808030 R15: ffff88003dfab6a0
FS:  0000000000000000(0000) GS:ffff880003420000(0000) knlGS:0000000000000000
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000000000008050 CR3: 000000003bc92000 CR4: 00000000001407e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process flush-0:22 (pid: 1665, threadinfo ffff88003dfaa000, task ffff880037f77540)
Stack:
ffffffffa0398ac1 ffff8800397c5940 ffff88003dfab610 ffff88003dfab6a0
<d> ffff88003dfab5d0 ffff88003dfab680 ffffffffa01c150b ffffea0000d82e70
<d> 000000508116713b 0000000000000000 0000000000000000 0000000000000000
Call Trace:
[<ffffffffa0398ac1>] ? xdr_inline_decode+0xb1/0x120 [sunrpc]
[<ffffffffa01c150b>] filelayout_decode_layout+0xeb/0x350 [nfs_layout_nfsv41_files]
[<ffffffffa01c17fc>] filelayout_alloc_lseg+0x8c/0x3c0 [nfs_layout_nfsv41_files]
[<ffffffff8150e6ce>] ? __wait_on_bit+0x7e/0x90
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

The current code in pnfs_destroy_all_layouts() assumes that removing
the layout from the server->layouts list is sufficient to make it
invisible to other processes. This ignores the fact that most
users access the layout through the nfs_inode->layout...
There is further breakage due to lack of reference counting of the
layouts, meaning that the whole thing Oopses at the drop of a hat.

The code in initiate_bulk_draining() is almost correct, and can be
used as a model for pnfs_destroy_all_layouts(), so move that
code to pnfs.c, and refactor the code to allow us to choose between
a single filesystem bulk recall, and a recall of all layouts.
Also note that initiate_bulk_draining() currently calls iput() while
holding locks. Fix that too.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

- Use uid_eq and gid_eq when comparing kuids and kgids.
- Use make_kuid(&init_user_ns, -2) and make_kgid(&init_user_ns, -2) as
  the initial uid and gid on nfs inodes, instead of using the typeunsafe
  value of -2.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

When reading uids and gids off the wire convert them to
kuids and kgids.

When putting kuids and kgids onto the wire first convert
them to uids and gids the other side will understand.

When printing kuids and kgids convert them to values in
the initial user namespace then use normal printf formats.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

When reading uids and gids off the wire convert them to
kuids and kgids.

When putting kuids and kgids onto the wire first convert
them to uids and gids the other side will understand.

Add an additional failure mode incoming for uids or gids
that are invalid.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

When reading uids and gids off the wire convert them to
kuids and kgids.

When putting kuids and kgids onto the wire first convert
them to uids and gids the other side will understand.

Add an additional failure mode for incoming uid or
gids that are invalid.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

Convert nfs_map_name_to_uid to return a kuid_t value.
Convert nfs_map_name_to_gid to return a kgid_t value.
Convert nfs_map_uid_to_name to take a kuid_t paramater.
Convert nfs_map_gid_to_name to take a kgid_t paramater.

Tweak nfs_fattr_map_owner_to_name to use a kuid_t intermediate value.
Tweak nfs_fattr_map_group_to_name to use a kgid_t intermediate value.

Which makes these functions properly handle kuids and kgids, including
erroring of the generated kuid or kgid is invalid.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

Ensure that if nfs_wait_on_sequence() causes our rpc task to wait for
an NFSv4 state serialisation lock, then we also drop the session slot.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

If the server reboots after it has replied to our OPEN, but before we
call nfs4_opendata_to_nfs4_state(), then the reboot recovery thread
will not see a stateid for this open, and so will fail to recover it.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Add a mutex to the struct nfs4_state_owner to ensure that delegation
recall doesn't conflict with byte range lock removal.

Note that we nest the new mutex _outside_ the state manager reclaim
protection (nfsi->rwsem) in order to avoid deadlocks.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Adjust the return values so that they return EAGAIN to the caller in
cases where we might want to retry the delegation recall after
the state recovery has run.
Note that we can't wait and retry in this routine, because the caller
may be the state manager thread.

If delegation recall fails due to a session or reboot related issue,
also ensure that we mark the stateid as delegated so that
nfs_delegation_claim_opens can find it again later.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the server reboots while we are converting a delegation into
OPEN/LOCK stateids as part of a delegation return, the current code
will simply exit with an error. This causes us to lose both
delegation state and locking state (i.e. locking atomicity).

Deal with this by exposing the delegation stateid during delegation
return, so that we can recover the delegation, and then resume
open/lock recovery.

Note that not having to hold the nfs_inode->rwsem across the
calls to nfs_delegation_claim_opens() also fixes a deadlock against
the NFSv4.1 reboot recovery code.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We currently have a deadlock in which the state recovery thread
ends up blocking due to one of the locks which it is trying to
recover holding the nfs_inode->rwsem.
The situation is as follows: the state recovery thread is
scheduled in order to recover from a reboot. It immediately
drains the session, forcing all ordinary NFSv4.1 calls to
nfs41_setup_sequence() to be put to sleep.  This includes the
file locking process that holds the nfs_inode->rwsem.
When the thread gets to nfs4_reclaim_locks(), it tries to
grab a write lock on nfs_inode->rwsem, and boom...

Fix is to have the lock drop the nfs_inode->rwsem while it is
doing RPC calls. We use a sequence lock in order to signal to
the locking process whether or not a state recovery thread has
run on that inode, in which case it should retry the lock.
Reported-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch adds a seqcount_t lock for use by the state manager to
signal that an open owner has been recovered. This mechanism will be
used by the delegation, open and byte range lock code in order to
figure out if they need to replay requests due to collisions with
lock recovery.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This reverts commit 324d003b.

The deadlock turned out to be caused by a workqueue limitation that has
now been worked around in the RPC code (see comment in rpc_free_task).
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

NFS4ERR_DELAY is a legal reply when we call DESTROY_SESSION. It
usually means that the server is busy handling an unfinished RPC
request. Just sleep for a second and then retry.
We also need to be able to handle the NFS4ERR_BACK_CHAN_BUSY return
value. If the NFS server has outstanding callbacks, we just want to
similarly sleep & retry.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

Ensure that any setattr and getattr requests for junctions and/or
mountpoints are sent to the server. Ever since commit
0ec26fd0 (vfs: automount should ignore LOOKUP_FOLLOW), we have
silently dropped any setattr requests to a server-side mountpoint.
For referrals, we have silently dropped both getattr and setattr
requests.

This patch restores the original behaviour for setattr on mountpoints,
and tries to do the same for referrals, provided that we have a
filehandle...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

We do need to start the lease recovery thread prior to waiting for the
client initialisation to complete in NFSv4.1.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Ben Greear <greearb@candelatech.com>
Cc: stable@vger.kernel.org [>=3.7]

If walking the list in nfs4[01]_walk_client_list fails, then the most
likely explanation is that the server dropped the clientid before we
actually managed to confirm it. As long as our nfs_client is the very
last one in the list to be tested, the caller can be assured that this
is the case when the final return value is NFS4ERR_STALE_CLIENTID.
Reported-by: NBen Greear <greearb@candelatech.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org [>=3.7]
Tested-by: NBen Greear <greearb@candelatech.com>

The reference counting in nfs4_init_client assumes wongly that it
is safe for nfs4_discover_server_trunking() to return a pointer to a
nfs_client prior to bumping the reference count.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Ben Greear <greearb@candelatech.com>
Cc: stable@vger.kernel.org [>=3.7]

Currently, nfs_xdev_mount converts all errors from clone_server() to
ENOMEM, which can then leak to userspace (for instance to 'mount'). Fix that.
Also ensure that if nfs_fs_mount_common() returns an error, we
don't dprintk(0)...

The regression originated in commit 3d176e3f
(NFS: Use nfs_fs_mount_common() for xdev mounts)
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 3.5]

Fix an inverted null pointer check in initiate_bulk_draining().
Signed-off-by: NNickolai Zeldovich <nickolai@csail.mit.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 3.7]

This patch ensures that we free the rpc_task after the cleanup callbacks
are done in order to avoid a deadlock problem that can be triggered if
the callback needs to wait for another workqueue item to complete.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Weston Andros Adamson <dros@netapp.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Bruce Fields <bfields@fieldses.org>
Cc: stable@vger.kernel.org [>= 3.5]

The following null pointer check is broken.

	*option = match_strdup(args);
	return !option;

The pointer `option' must be non-null, and thus `!option' is always false.
Use `!*option' instead.

The bug was introduced in commit c5cb09b6 ("Cleanup: Factor out some
cut-and-paste code.").
Signed-off-by: NXi Wang <xi.wang@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The layout will be set unusable if LAYOUTGET fails. Is it reasonable to
increase the refcount iff LAYOUTGET fails the first time?
Signed-off-by: NYanchuan Nian <ycnian@gmail.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 3.7]

nfs_open_permission_mask() should only check MAY_EXEC for files that
are opened with __FMODE_EXEC.

Also fix NFSv4 access-in-open path in a similar way -- openflags must be
used because fmode will not always have FMODE_EXEC set.

This patch fixes https://bugzilla.kernel.org/show_bug.cgi?id=49101Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

The fscache code will currently bleat a "non-unique superblock keys"
warning even if the user is mounting without the 'fsc' option.

There should be no reason to even initialise the superblock cache cookie
unless we're planning on using fscache for something, so ensure that we
check for the NFS_OPTION_FSCACHE flag before calling into the fscache
code.
Reported-by: NPaweł Sikora <pawel.sikora@agmk.net>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Provide a stub nfs_fscache_wait_on_invalidate() function for when
CONFIG_NFS_FSCACHE=n lest the following error appear:

  fs/nfs/inode.c: In function 'nfs_invalidate_mapping':
  fs/nfs/inode.c:887:2: error: implicit declaration of function 'nfs_fscache_wait_on_invalidate' [-Werror=implicit-function-declaration]
  cc1: some warnings being treated as errors
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Reported-by: NVineet Gupta <Vineet.Gupta1@synopsys.com>
Reported-by: NBorislav Petkov <bp@alien8.de>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

nfs4_file_open() should open files for fscaching.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

nfs_migrate_page() does not wait for FS-Cache to finish with a page, probably
leading to the following bad-page-state:

 BUG: Bad page state in process python-bin  pfn:17d39b
 page:ffffea00053649e8 flags:004000000000100c count:0 mapcount:0 mapping:(null)
index:38686 (Tainted: G    B      ---------------- )
 Pid: 31053, comm: python-bin Tainted: G    B      ----------------
2.6.32-71.24.1.el6.x86_64 #1
 Call Trace:
 [<ffffffff8111bfe7>] bad_page+0x107/0x160
 [<ffffffff8111ee69>] free_hot_cold_page+0x1c9/0x220
 [<ffffffff8111ef19>] __pagevec_free+0x59/0xb0
 [<ffffffff8104b988>] ? flush_tlb_others_ipi+0x128/0x130
 [<ffffffff8112230c>] release_pages+0x21c/0x250
 [<ffffffff8115b92a>] ? remove_migration_pte+0x28a/0x2b0
 [<ffffffff8115f3f8>] ? mem_cgroup_get_reclaim_stat_from_page+0x18/0x70
 [<ffffffff81122687>] ____pagevec_lru_add+0x167/0x180
 [<ffffffff811226f8>] __lru_cache_add+0x58/0x70
 [<ffffffff81122731>] lru_cache_add_lru+0x21/0x40
 [<ffffffff81123f49>] putback_lru_page+0x69/0x100
 [<ffffffff8115c0bd>] migrate_pages+0x13d/0x5d0
 [<ffffffff81122687>] ? ____pagevec_lru_add+0x167/0x180
 [<ffffffff81152ab0>] ? compaction_alloc+0x0/0x370
 [<ffffffff8115255c>] compact_zone+0x4cc/0x600
 [<ffffffff8111cfac>] ? get_page_from_freelist+0x15c/0x820
 [<ffffffff810672f4>] ? check_preempt_wakeup+0x1c4/0x3c0
 [<ffffffff8115290e>] compact_zone_order+0x7e/0xb0
 [<ffffffff81152a49>] try_to_compact_pages+0x109/0x170
 [<ffffffff8111e94d>] __alloc_pages_nodemask+0x5ed/0x850
 [<ffffffff814c9136>] ? thread_return+0x4e/0x778
 [<ffffffff81150d43>] alloc_pages_vma+0x93/0x150
 [<ffffffff81167ea5>] do_huge_pmd_anonymous_page+0x135/0x340
 [<ffffffff814cb6f6>] ? rwsem_down_read_failed+0x26/0x30
 [<ffffffff81136755>] handle_mm_fault+0x245/0x2b0
 [<ffffffff814ce383>] do_page_fault+0x123/0x3a0
 [<ffffffff814cbdf5>] page_fault+0x25/0x30

nfs_migrate_page() calls nfs_fscache_release_page() which doesn't actually wait
- even if __GFP_WAIT is set.  The reason that doesn't wait is that
fscache_maybe_release_page() might deadlock the allocator as the work threads
writing to the cache may all end up sleeping on memory allocation.

However, I wonder if that is actually a problem.  There are a number of things
I can do to deal with this:

 (1) Make nfs_migrate_page() wait.

 (2) Make fscache_maybe_release_page() honour the __GFP_WAIT flag.

 (3) Set a timeout around the wait.

 (4) Make nfs_migrate_page() return an error if the page is still busy.

For the moment, I'll select (2) and (4).
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NJeff Layton <jlayton@redhat.com>

Use the new FS-Cache invalidation facility from NFS to deal with foreign
changes being detected on the server rather than attempting to retire the old
cookie and get a new one.

The problem with the old method was that NFS did not wait for all outstanding
storage and retrieval ops on the cache to complete.  There was no automatic
wait between the calls to ->readpages() and calls to invalidate_inode_pages2()
as the latter can only wait on locked pages that have been added to the
pagecache (which they haven't yet on entry to ->readpages()).

This was leading to oopses like the one below when an outstanding read got cut
off from its cookie by a premature release.

BUG: unable to handle kernel NULL pointer dereference at 00000000000000a8
IP: [<ffffffffa0075118>] __fscache_read_or_alloc_pages+0x1dd/0x315 [fscache]
PGD 15889067 PUD 15890067 PMD 0
Oops: 0000 [#1] SMP
CPU 0
Modules linked in: cachefiles nfs fscache auth_rpcgss nfs_acl lockd sunrpc

Pid: 4544, comm: tar Not tainted 3.1.0-rc4-fsdevel+ #1064                  /DG965RY
RIP: 0010:[<ffffffffa0075118>]  [<ffffffffa0075118>] __fscache_read_or_alloc_pages+0x1dd/0x315 [fscache]
RSP: 0018:ffff8800158799e8  EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8800070d41e0 RCX: ffff8800083dc1b0
RDX: 0000000000000000 RSI: ffff880015879960 RDI: ffff88003e627b90
RBP: ffff880015879a28 R08: 0000000000000002 R09: 0000000000000002
R10: 0000000000000001 R11: ffff880015879950 R12: ffff880015879aa4
R13: 0000000000000000 R14: ffff8800083dc158 R15: ffff880015879be8
FS:  00007f671e9d87c0(0000) GS:ffff88003bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000000000000a8 CR3: 000000001587f000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process tar (pid: 4544, threadinfo ffff880015878000, task ffff880015875040)
Stack:
 ffffffffa00b1759 ffff8800070dc158 ffff8800000213da ffff88002a286508
 ffff880015879aa4 ffff880015879be8 0000000000000001 ffff88002a2866e8
 ffff880015879a88 ffffffffa00b20be 00000000000200da ffff880015875040
Call Trace:
 [<ffffffffa00b1759>] ? nfs_fscache_wait_bit+0xd/0xd [nfs]
 [<ffffffffa00b20be>] __nfs_readpages_from_fscache+0x7e/0x13f [nfs]
 [<ffffffff81095fe7>] ? __alloc_pages_nodemask+0x156/0x662
 [<ffffffffa0098763>] nfs_readpages+0xee/0x187 [nfs]
 [<ffffffff81098a5e>] __do_page_cache_readahead+0x1be/0x267
 [<ffffffff81098942>] ? __do_page_cache_readahead+0xa2/0x267
 [<ffffffff81098d7b>] ra_submit+0x1c/0x20
 [<ffffffff8109900a>] ondemand_readahead+0x28b/0x29a
 [<ffffffff810990ce>] page_cache_sync_readahead+0x38/0x3a
 [<ffffffff81091d8a>] generic_file_aio_read+0x2ab/0x67e
 [<ffffffffa008cfbe>] nfs_file_read+0xa4/0xc9 [nfs]
 [<ffffffff810c22c4>] do_sync_read+0xba/0xfa
 [<ffffffff810a62c9>] ? might_fault+0x4e/0x9e
 [<ffffffff81177a47>] ? security_file_permission+0x7b/0x84
 [<ffffffff810c25dd>] ? rw_verify_area+0xab/0xc8
 [<ffffffff810c29a4>] vfs_read+0xaa/0x13a
 [<ffffffff810c2a79>] sys_read+0x45/0x6c
 [<ffffffff813ac37b>] system_call_fastpath+0x16/0x1b
Reported-by: NMark Moseley <moseleymark@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

But the kernel decided to call it "origin" instead.  Fix most of the
sites.
Acked-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The writeback code is already capable of passing errors back to user space
by means of the open_context->error. In the case of ENOSPC, Neil Brown
is reporting seeing 2 errors being returned.

Neil writes:

"e.g. if /mnt2/ if an nfs mounted filesystem that has no space then

strace dd if=/dev/zero conv=fsync >> /mnt2/afile count=1

reported Input/output error and the relevant parts of the strace output are:

write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 512) = 512
fsync(1)                                = -1 EIO (Input/output error)
close(1)                                = -1 ENOSPC (No space left on device)"

Neil then shows that the duplication of error messages appears to be due to
the use of the PageError() mechanism, which causes filemap_fdatawait_range
to return the extra EIO. The regression was introduced by
commit 7b281ee0 (NFS: fsync() must exit
with an error if page writeback failed).

Fix this by removing the call to SetPageError(), and just relying on
open_context->error reporting the ENOSPC back to fsync().
Reported-by: NNeil Brown <neilb@suse.de>
Tested-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [3.6+]

If an RPC call is interrupted, assume that the server hasn't processed
the RPC call so that the next time we use the slot, we know that if we
get a NFS4ERR_SEQ_MISORDERED or NFS4ERR_SEQ_FALSE_RETRY, we just have
to bump the sequence number.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>