NFS_LAYOUT_RETURN_BEFORE_CLOSE is being used to signal that a
layoutreturn is needed, either due to a layout recall or to a
layout error. Rename it to NFS_LAYOUT_RETURN_REQUESTED in order
to clarify its purpose.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The layoutreturn code currently relies on pnfs_put_lseg() to initiate the
RPC call when conditions are right. A problem arises when we want to
free the layout segment from inside an inode->i_lock section (e.g. in
pnfs_clear_request_commit()), since we cannot sleep.

The workaround is to move the actual call to pnfs_send_layoutreturn()
to pnfs_put_layout_hdr(), which doesn't have this restriction.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We must not skip encoding the statistics, or the server will see an
XDR encoding error.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # 4.0+

I noticed that all the callers of this function pass cinfo->mds->list as
an argument in addition to the cinfo structure itself.  Let's get rid of
the extra argument, since it doesn't seem to be adding anything.
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When we hit 22 errors, we start to overflow the memory buffers allocated
to the LAYOUTRETURN errors. The issue is that currently, RPC call reply
ordering determines how successful we are in merging errors that refer
to contiguous READ or WRITE requests.

Fix is to use an insertion sort to help detect contiguity.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Mark those kmem allocations that are known to be easily triggered from
userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
memcg.  For the list, see below:

 - threadinfo
 - task_struct
 - task_delay_info
 - pid
 - cred
 - mm_struct
 - vm_area_struct and vm_region (nommu)
 - anon_vma and anon_vma_chain
 - signal_struct
 - sighand_struct
 - fs_struct
 - files_struct
 - fdtable and fdtable->full_fds_bits
 - dentry and external_name
 - inode for all filesystems. This is the most tedious part, because
   most filesystems overwrite the alloc_inode method.

The list is far from complete, so feel free to add more objects.
Nevertheless, it should be close to "account everything" approach and
keep most workloads within bounds.  Malevolent users will be able to
breach the limit, but this was possible even with the former "account
everything" approach (simply because it did not account everything in
fact).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

inode_nohighmem() is sufficient to make sure that page_get_link()
won't try to allocate a highmem page.  Moreover, it is sufficient
to make sure that page_symlink/__page_symlink won't do the same
thing.  However, any filesystem that manually preseeds the symlink's
page cache upon symlink(2) needs to make sure that the page it
inserts there won't be a highmem one.

Fortunately, only nfs and shmem have run afoul of that...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The use of wait_on_atomic_t() for waiting on I/O to complete before
unlocking allows us to git rid of the NFS_IO_INPROGRESS flag, and thus the
nfs_iocounter's flags member, and finally the nfs_iocounter altogether.
The count of I/O is moved to the lock context, and the counter
increment/decrement functions become simple enough to open-code.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
[Trond: Fix up conflict with existing function nfs_wait_atomic_killable()]
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Make it more obvious what we're returning...
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Peng Tao points out that the call to pnfs_mark_matching_lsegs_return()
could race with pnfs_put_lseg(), in which case the layout segment is
cleared, but no layoutreturn will be sent.
Fix is to replace the call to pnfs_mark_matching_lsegs_invalid().
Reported-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Fix a bug whereby if all the layout segments could be immediately freed,
the call to pnfs_error_mark_layout_for_return() would never result in
a layoutreturn.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If pnfs_mark_matching_lsegs_return() needs to mark a layout segment for
return, then it must also set the return iomode.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

A stateid is a structure, pass it as a pointer.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If two processes share the same credentials and NFSv4 open stateid, then
allow them both to dirty the same page, even if their nfs_open_context
differs.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

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

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

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

The flexfiles layout in particular, seems to want to poke around in the
O_DIRECT flags when retransmitting.
This patch sets up an interface to allow it to call back into O_DIRECT
to handle retransmission correctly. It also fixes a potential bug whereby
we could change the behaviour of O_DIRECT if an error is already pending.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

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

Jeff reports seeing an Oops in ff_layout_alloc_lseg. Turns out
copy+paste has played cruel tricks on a nested loop.
Reported-by: NJeff Layton <jeff.layton@primarydata.com>
Cc: stable@vger.kernel.org # 4.3+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If a NFSv4 client uses the cache_consistency_bitmask in order to
request only information about the change attribute, timestamps and
size, then it has not revalidated all attributes, and hence the
attribute timeout timestamp should not be updated.
Reported-by: NDonald Buczek <buczek@molgen.mpg.de>
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Donald Buczek reports that NFS clients can also report incorrect
results for access() due to lack of revalidation of attributes
before calling execute_ok().
Looking closely, it seems chdir() is afflicted with the same problem.

Fix is to ensure we call nfs_revalidate_inode_rcu() or
nfs_revalidate_inode() as appropriate before deciding to trust
execute_ok().
Reported-by: NDonald Buczek <buczek@molgen.mpg.de>
Link: http://lkml.kernel.org/r/1451331530-3748-1-git-send-email-buczek@molgen.mpg.deSigned-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The stateid is extremely valuable when debugging.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the client is promising to return the layout ASAP, then there is no
need to return DELAY and have the server retry. Instead default to the
normal procedure described in RFC5661.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The RFC requires us to check if the server is recalling a stateid that we
haven't yet received. If so, tell it to wait.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the client needs to delay the layout callback, then speed up the recall
process by marking the remaining layout segments to be actively returned
by the client.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This ensures that we don't reuse the stateid if a layout return or
implied layout return means that we've returned all layout segments
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If we're unable to perform the layoutget due to an invalid open stateid
or a bulk recall, ensure that we return the error so that the caller
can decide on an appropriate action.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Currently, we will only record the layoutstats correctly if the
RPC call successfully obtains a slot. If we exit before that
happens, then we may find ourselves starting the busy timer through
the call in ff_layout_(read|write)_prepare_layoutstats, but never stopping it.

The same thing happens if we're doing DA-DS.

The fix is to ensure that we catch these cases in the rpc_release()
callback.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When we replay a failed read, write or commit to the dataserver, we
need to ensure that we call ff_layout_read_prepare_v3(),
ff_layout_write_prepare_v3 or ff_layout_commit_prepare_v3() so that we
reset the statistics.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

In pNFS/flexfiles, we want to return the layout without necessarily marking
it as having completely failed. We therefore move the call to
pnfs_layout_io_set_failed() out of pnfs_error_mark_layout_for_return(),
and then ensura that pNFS/files layout calls it separately.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Fix a bug in which flexfiles clients are falling back to I/O through the
MDS even when the FF_FLAGS_NO_IO_THRU_MDS flag is set.

The flexfiles client will always report errors through the LAYOUTRETURN
and/or LAYOUTERROR mechanisms, so it should normally be safe for it
to retry the LAYOUTGET until it fails or succeeds.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If client ever restarts IO due to some errors, we'll endup
mis-counting IO stats if we do the counting in .rpc_done
callback. Move it to .rpc_count_stats callback that is only
called when releasing RPC.
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We just need to delay and retry in these cases.
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>