NFS: avoid infinite loop in pnfs_update_layout.

If pnfsd_update_layout() is called on a file for which recovery has
failed it will enter a tight infinite loop.

NFS_LAYOUT_INVALID_STID will be set, nfs4_select_rw_stateid() will
return -EIO, and nfs4_schedule_stateid_recovery() will do nothing, so
nfs4_client_recover_expired_lease() will not wait. So the code will
loop indefinitely.

Break the loop by testing the validity of the open stateid at the top of
the loop.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Fix the pnfs block driver's calculation of layoutget size

Instead of relying on the value of the 'bytes_left' field, we should
calculate the layout size based on the offset of the request that is
being written out.

Reported-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Fixes: 954998b60caa ("NFS: Fix error handling for O_DIRECT write scheduling")
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4/pnfs: Allow layoutget to return EAGAIN for softerr mounts

If we're using the 'softerr' mount option, we may want to allow
layoutget to return EAGAIN to allow knfsd server threads to return a
JUKEBOX/DELAY error to the client instead of busy waiting.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Fix a hang in nfs4_evict_inode()

We are not allowed to call pnfs_mark_matching_lsegs_return() without
also holding a reference to the layout header, since doing so could lead
to the reference count going to zero when we call
pnfs_layout_remove_lseg(). This again can lead to a hang when we get to
nfs4_evict_inode() and are unable to clear the layout pointer.

pnfs_layout_return_unused_byserver() is guilty of this behaviour, and
has been seen to trigger the refcount warning prior to a hang.

Fixes: b6d49ecd1081 ("NFSv4: Fix a pNFS layout related use-after-free race when freeing the inode")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS/filelayout: treat GETDEVICEINFO errors as layout failure

When GETDEVICEINFO call fails, return the layout and fall back to MDS.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4/flexfiles: Cancel I/O if the layout is recalled or revoked

If the layout is recalled or revoked, we want to cancel I/O as quickly
as possible so that we can return the layout.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

freezer,sched: Rewrite core freezer logic

Rewrite the core freezer to behave better wrt thawing and be simpler
in general.

By replacing PF_FROZEN with TASK_FROZEN, a special block state, it is
ensured frozen tasks stay frozen until thawed and don't randomly wake
up early, as is currently possible.

As such, it does away with PF_FROZEN and PF_FREEZER_SKIP, freeing up
two PF_flags (yay!).

Specifically; the current scheme works a little like:

freezer_do_not_count();
schedule();
freezer_count();

And either the task is blocked, or it lands in try_to_freezer()
through freezer_count(). Now, when it is blocked, the freezer
considers it frozen and continues.

However, on thawing, once pm_freezing is cleared, freezer_count()
stops working, and any random/spurious wakeup will let a task run
before its time.

That is, thawing tries to thaw things in explicit order; kernel
threads and workqueues before doing bringing SMP back before userspace
etc.. However due to the above mentioned races it is entirely possible
for userspace tasks to thaw (by accident) before SMP is back.

This can be a fatal problem in asymmetric ISA architectures (eg ARMv9)
where the userspace task requires a special CPU to run.

As said; replace this with a special task state TASK_FROZEN and add
the following state transitions:

TASK_FREEZABLE -> TASK_FROZEN
__TASK_STOPPED -> TASK_FROZEN
__TASK_TRACED -> TASK_FROZEN

The new TASK_FREEZABLE can be set on any state part of TASK_NORMAL
(IOW. TASK_INTERRUPTIBLE and TASK_UNINTERRUPTIBLE) -- any such state
is already required to deal with spurious wakeups and the freezer
causes one such when thawing the task (since the original state is
lost).

The special __TASK_{STOPPED,TRACED} states *can* be restored since
their canonical state is in ->jobctl.

With this, frozen tasks need an explicit TASK_FROZEN wakeup and are
free of undue (early / spurious) wakeups.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20220822114649.055452969@infradead.org

NFS: Remove a bogus flag setting in pnfs_write_done_resend_to_mds

Since pnfs_write_done_resend_to_mds() does not actually call
end_page_writeback() on the pages that are being redirected to the
metadata server, callers of fsync() do not see the I/O as complete until
the writeback to the MDS finishes. We therefore do not need to set
NFS_CONTEXT_RESEND_WRITES, since there is nothing to redrive.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Avoid a live lock condition in pnfs_update_layout()

If we're about to send the first layoutget for an empty layout, we want
to make sure that we drain out the existing pending layoutget calls
first. The reason is that these layouts may have been already implicitly
returned to the server by a recall to which the client gave a
NFS4ERR_NOMATCHING_LAYOUT response.

The problem is that wait_var_event_killable() could in principle see the
plh_outstanding count go back to '1' when the first process to wake up
starts sending a new layoutget. If it fails to get a layout, then this
loop can continue ad infinitum...

Fixes: 0b77f97a7e42 ("NFSv4/pnfs: Fix layoutget behaviour after invalidation")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS: Don't keep retrying if the server replied NFS4ERR_LAYOUTUNAVAILABLE

If the server tells us that a pNFS layout is not available for a
specific file, then we should not keep pounding it with further
layoutget requests.

Fixes: 183d9e7b112a ("pnfs: rework LAYOUTGET retry handling")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4/pNFS: Do not fail I/O when we fail to allocate the pNFS layout

Commit 587f03deb69b caused pnfs_update_layout() to stop returning ENOMEM
when the memory allocation fails, and hence causes it to fall back to
trying to do I/O through the MDS. There is no guarantee that this will
fare any better. If we're failing the pNFS layout allocation, then we
should just redirty the page and retry later.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: 587f03deb69b ("pnfs: refactor send_layoutget")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4/pNFS: Fix another issue with a list iterator pointing to the head

In nfs4_callback_devicenotify(), if we don't find a matching entry for
the deviceid, we're left with a pointer to 'struct nfs_server' that
actually points to the list of super blocks associated with our struct
nfs_client.
Furthermore, even if we have a valid pointer, nothing pins the super
block, and so the struct nfs_server could end up getting freed while
we're using it.

Since all we want is a pointer to the struct pnfs_layoutdriver_type,
let's skip all the iteration over super blocks, and just use APIs to
find the layout driver directly.

Reported-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Fixes: 1be5683b03a7 ("pnfs: CB_NOTIFY_DEVICEID")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4/pnfs: Ensure pNFS allocation modes are consistent with nfsiod

Ensure that pNFS allocations that can be called from rpciod/nfsiod
callback can fail in low memory mode, so that the threads don't block
and loop forever.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Convert GFP_NOFS to GFP_KERNEL

Assume that sections that should not re-enter the filesystem are already
protected with memalloc_nofs_save/restore call, so relax those GFP_NOFS
instances which might be used by other contexts.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4/pnfs: The layout barrier indicate a minimal value for the seqid

The intention of the layout barrier is to ensure that we do not update
the layout to match an older value than the current expectation. Fix the
test in pnfs_layout_stateid_blocked() to reflect that it is legal for
the seqid of the stateid to match that of the barrier.

Fixes: aa95edf309ef ("NFSv4/pnfs: Fix the layout barrier update")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4/pNFS: Always allow update of a zero valued layout barrier

A zero value for the layout barrier indicates that it has been cleared
(since seqid '0' is an illegal value), so we should always allow it to
be updated.

Fixes: d29b468da4f9 ("pNFS/NFSv4: Improve rejection of out-of-order layouts")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4/pNFS: Remove dead code

Since commit 2b28a7bee453 ("fs, nfs: convert
pnfs_layout_hdr.plh_refcount from atomic_t to refcount_t") it has not
been legal to bump a zero refcount, so the code that tries to allow it
if the NFS_LSEG_VALID flag is still set would cause trouble. Luckily,
NFS_LSEG_VALID has its own refcount so we can never hit this bad code
snippet in practice. Remove it to avoid confusion.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4/pNFS: Fix a layoutget livelock loop

If NFS_LAYOUT_RETURN_REQUESTED is set, but there is no value set for
the layout plh_return_seq, we can end up in a livelock loop in which
every layout segment retrieved by a new call to layoutget is immediately
invalidated by pnfs_layout_need_return().
To get around this, we should just set plh_return_seq to the current
value of the layout stateid's seqid.

Fixes: d474f96104bd ("NFS: Don't return layout segments that are in use")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4/pnfs: Clean up layout get on open

Cache the layout in the arguments so we don't have to keep looking it up
from the inode.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4/pnfs: Fix layoutget behaviour after invalidation

If the layout gets invalidated, we should wait for any outstanding
layoutget requests for that layout to complete, and we should resend
them only after re-establishing the layout stateid.

Fixes: d29b468da4f9 ("pNFS/NFSv4: Improve rejection of out-of-order layouts")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4/pnfs: Fix the layout barrier update

If we have multiple outstanding layoutget requests, the current code to
update the layout barrier assumes that the outstanding layout stateids
are updated in order. That's not necessarily the case.

Instead of using the value of lo->plh_outstanding as a guesstimate for
the window of values we need to accept, just wait to update the window
until we're processing the last one. The intention here is just to
ensure that we don't process 2^31 seqid updates without also updating
the barrier.

Fixes: 1bcf34fdac5f ("pNFS/NFSv4: Update the layout barrier when we schedule a layoutreturn")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4: Fix a NULL pointer dereference in pnfs_mark_matching_lsegs_return()

Commit de144ff4234f changes _pnfs_return_layout() to call
pnfs_mark_matching_lsegs_return() passing NULL as the struct
pnfs_layout_range argument. Unfortunately,
pnfs_mark_matching_lsegs_return() doesn't check if we have a value here
before dereferencing it, causing an oops.

I'm able to hit this crash consistently when running connectathon basic
tests on NFS v4.1/v4.2 against Ontap.

Fixes: de144ff4234f ("NFSv4: Don't discard segments marked for return in _pnfs_return_layout()")
Cc: stable@vger.kernel.org
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS/NFSv4: Remove redundant initialization of 'rd_size'

Variable 'rd_size' is being initialized however
this value is never read as 'rd_size' is assigned
a new value in for statement. Remove the redundant
assignment.

Clean up clang warning:

fs/nfs/pnfs.c:2681:6: warning: Value stored to 'rd_size' during its
initialization is never read [clang-analyzer-deadcode.DeadStores]

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4.1: Simplify layout return in pnfs_layout_process()

If the server hands us a layout that does not match the one we currently
hold, then have pnfs_mark_matching_lsegs_return() just ditch the old
layout if NFS_LSEG_LAYOUTRETURN is not set.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4: Don't discard segments marked for return in _pnfs_return_layout()

If the pNFS layout segment is marked with the NFS_LSEG_LAYOUTRETURN
flag, then the assumption is that it has some reporting requirement
to perform through a layoutreturn (e.g. flexfiles layout stats or error
information).

Fixes: 6d597e175012 ("pnfs: only tear down lsegs that precede seqid in LAYOUTRETURN args")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Don't discard pNFS layout segments that are marked for return

If the pNFS layout segment is marked with the NFS_LSEG_LAYOUTRETURN
flag, then the assumption is that it has some reporting requirement
to perform through a layoutreturn (e.g. flexfiles layout stats or error
information).

Fixes: e0b7d420f72a ("pNFS: Don't discard layout segments that are marked for return")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

nfs: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple
warnings by explicitly add multiple break/goto/return/fallthrough
statements instead of just letting the code fall through to the next
case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS/NFSv4: Improve rejection of out-of-order layouts

If a layoutget ends up being reordered w.r.t. a layoutreturn, e.g. due
to a layoutget-on-open not knowing a priori which file to lock, then we
must assume the layout is no longer being considered valid state by the
server.
Incrementally improve our ability to reject such states by using the
cached old stateid in conjunction with the plh_barrier to try to
identify them.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS/NFSv4: Update the layout barrier when we schedule a layoutreturn

When we're scheduling a layoutreturn, we need to ignore any further
incoming layouts with sequence ids that are going to be affected by the
layout return.

Fixes: 44ea8dfce021 ("NFS/pnfs: Reference the layout cred in pnfs_prepare_layoutreturn()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS/NFSv4: Try to return invalid layout in pnfs_layout_process()

If the server returns a new stateid that does not match the one in our
cache, then try to return the one we hold instead of just invalidating
it on the client side. This ensures that both client and server will
agree that the stateid is invalid.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS/NFSv4: Fix a layout segment leak in pnfs_layout_process()

If the server returns a new stateid that does not match the one in our
cache, then pnfs_layout_process() will leak the layout segments returned
by pnfs_mark_layout_stateid_invalid().

Fixes: 9888d837f3cf ("pNFS: Force a retry of LAYOUTGET if the stateid doesn't match our cache")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS/pNFS: Fix a leak of the layout 'plh_outstanding' counter

If we exit _lgopen_prepare_attached() without setting a layout, we will
currently leak the plh_outstanding counter.

Fixes: 411ae722d10a ("pNFS: Wait for stale layoutget calls to complete in pnfs_update_layout()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Stricter ordering of layoutget and layoutreturn

If a layout return is in progress, we should wait for it to complete,
in case the layout segment we are picking up gets returned too.

Fixes: 30cb3ee299cb ("pNFS: Handle NFS4ERR_OLD_STATEID on layoutreturn by bumping the state seqid")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Clean up pnfs_layoutreturn_free_lsegs()

Remove the check for whether or not the stateid is NULL, and fix up the
callers.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: We want return-on-close to complete when evicting the inode

If the inode is being evicted, it should be safe to run return-on-close,
so we should do it to ensure we don't inadvertently leak layout segments.

Fixes: 1c5bd76d17cc ("pNFS: Enable layoutreturn operation for return-on-close")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Mark layout for return if return-on-close was not sent

If the layout return-on-close failed because the layoutreturn was never
sent, then we should mark the layout for return again.

Fixes: 9c47b18cf722 ("pNFS: Ensure we do clear the return-on-close layout stateid on fatal errors")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4: Fix a pNFS layout related use-after-free race when freeing the inode

When returning the layout in nfs4_evict_inode(), we need to ensure that
the layout is actually done being freed before we can proceed to free the
inode itself.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

nfs: fix spellint typo in pnfs.c

Change the comment typo: "manger" -> "manager".

Signed-off-by: Wang Qing <wangqing@vivo.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

NFS: Fix flexfiles read failover

The current mirrored read failover code is correctly resetting the mirror
index between failed reads, however it is not able to actually flip the
RPC call over to the next RPC client.
The end result is that we keep resending the RPC call to the same client
over and over.

The fix is to use the pnfs_read_resend_pnfs() mechanism to schedule a
new RPC call, but we need to add the ability to pass in a mirror
index so that we always retry the next mirror in the list.

Fixes: 166bd5b889ac ("pNFS/flexfiles: Fix layoutstats handling during read failovers")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Don't return layout segments that are in use

If the NFS_LAYOUT_RETURN_REQUESTED flag is set, we want to return the
layout as soon as possible, meaning that the affected layout segments
should be marked as invalid, and should no longer be in use for I/O.

Fixes: f0b429819b5f ("pNFS: Ignore non-recalled layouts in pnfs_layout_need_return()")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Don't move layouts to plh_return_segs list while in use

If the layout segment is still in use for a read or a write, we should
not move it to the layout plh_return_segs list. If we do, we can end
up returning the layout while I/O is still in progress.

Fixes: e0b7d420f72a ("pNFS: Don't discard layout segments that are marked for return")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Report the stateid + status in trace_nfs4_layoutreturn_on_close()

Ensure we correctly report the stateid and status in the layoutreturn on
close tracepoint.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS/pnfs: Fix a credential use-after-free issue in pnfs_roc()

If the credential returned by pnfs_prepare_layoutreturn()
does not match the credential of the RPC call, then we do
end up calling pnfs_send_layoutreturn() with that credential,
so don't free it!

Fixes: 44ea8dfce021 ("NFS/pnfs: Reference the layout cred in pnfs_prepare_layoutreturn()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS/pnfs: Ensure that _pnfs_return_layout() waits for layoutreturn completion

We require that any outstanding layout return completes before we can
free up the inode so that the layout itself can be freed.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Fix an ABBA spinlock issue in pnfs_update_layout()

We need to drop the inode spinlock while calling nfs4_select_rw_stateid(),
since nfs4_copy_delegation_stateid() could take the delegation lock.
Note that it is safe to do this, since all other calls to
pnfs_update_layout() for that inode will find themselves blocked by
the lock we hold on NFS_LAYOUT_FIRST_LAYOUTGET.

Fixes: fc51b1cf391d ("NFS: Beware when dereferencing the delegation cred")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS/pnfs: Reference the layout cred in pnfs_prepare_layoutreturn()

When we're sending a layoutreturn, ensure that we reference the
layout cred atomically with the copy of the stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS/pnfs: Fix dereference of layout cred in pnfs_layoutcommit_inode()

Ensure that the dereference of the layout cred is atomic with the
stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS/flexfiles: Check the layout segment range before doing I/O

When starting to read or write with a layout segment, check that the
range matches our request.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Add infrastructure for cleaning up per-layout commit structures

Ensure that both the file and flexfiles layout types clean up when
freeing the layout segments.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4: Add support for CB_RECALL_ANY for flexfiles layouts

When we receive a CB_RECALL_ANY that asks us to return flexfiles
layouts, we iterate through all the layouts and look at whether or
not there are active open file descriptors that might need them
for I/O. If there are no such descriptors, we return the layouts.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4: Ensure layout headers are RCU safe

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4: Avoid unnecessary credential references in layoutget

Layoutget is just using the credential attached to the open context.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4/pnfs: pnfs_set_layout_stateid() should update the layout cred

If the cred assigned to the layout that we're updating differs from
the one used to retrieve the new layout segment, then we need to
update the layout plh_lc_cred field.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4: pnfs_roc() must use cred_fscmp() to compare creds

When comparing two 'struct cred' for equality w.r.t. behaviour under
filesystem access, we need to use cred_fscmp().

Fixes: a52458b48af1 ("NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4.x recover from pre-mature loss of openstateid

Ever since the commit 0e0cb35b417f, it's possible to lose an open stateid
while retrying a CLOSE due to ERR_OLD_STATEID. Once that happens,
operations that require openstateid fail with EAGAIN which is propagated
to the application then tests like generic/446 and generic/168 fail with
"Resource temporarily unavailable".

Instead of returning this error, initiate state recovery when possible to
recover the open stateid and then try calling nfs4_select_rw_stateid()
again.

Fixes: 0e0cb35b417f ("NFSv4: Handle NFS4ERR_OLD_STATEID in CLOSE/OPEN_DOWNGRADE")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4: add declaration of current_stateid

The current_stateid is exported from nfs4state.c but not
declared in any of the headers. Add to nfs4_fs.h to
remove the following warning:

fs/nfs/nfs4state.c:80:20: warning: symbol 'current_stateid' was not declared. Should it be static?

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Handle NFS4ERR_OLD_STATEID on layoutreturn by bumping the state seqid

If a LAYOUTRETURN receives a reply of NFS4ERR_OLD_STATEID then assume we've
missed an update, and just bump the stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4: Handle RPC level errors in LAYOUTRETURN

Handle RPC level errors by assuming that the RPC call was successful.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4: Handle NFS4ERR_DELAY correctly in return-on-close

If the server sends a NFS4ERR_DELAY, then allow the caller to retry.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4: Clean up pNFS return-on-close error handling

Both close and delegreturn have identical code to handle pNFS
return-on-close. This patch refactors that code and places it
in pnfs.c

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS: Ensure we do clear the return-on-close layout stateid on fatal errors

IF the server rejected our layout return with a state error such as
NFS4ERR_BAD_STATEID, or even a stale inode error, then we do want
to clear out all the remaining layout segments and mark that stateid
as invalid.

Fixes: 1c5bd76d17cca ("pNFS: Enable layoutreturn operation for...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4: Report the error from nfs4_select_rw_stateid()

In pnfs_update_layout() ensure that we do report any fatal errors from
nfs4_select_rw_stateid().

Fixes: d9aba2b40de6 ("NFSv4: Don't use the zero stateid with layoutget")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs/flexfiles: Add tracepoints for detecting pnfs fallback to MDS

Add tracepoints to allow debugging of the event chain leading to
a pnfs fallback to doing I/O through the MDS.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs: Fix a problem where we gratuitously start doing I/O through the MDS

If the client has to stop in pnfs_update_layout() to wait for another
layoutget to complete, it currently exits and defaults to I/O through
the MDS if the layoutget was successful.

Fixes: d03360aaf5cc ("pNFS: Ensure we return the error if someone kills...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.20+

NFSv4: Don't use the zero stateid with layoutget

The NFSv4.1 protocol explicitly forbids us from using the zero stateid
together with layoutget, so when we see that nfs4_select_rw_stateid()
is unable to return a valid delegation, lock or open stateid, then
we should initiate recovery and retry.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Clean up writeback code

Now that the VM promises never to recurse back into the filesystem
layer on writeback, remove all the GFP_NOFS references etc from
the generic writeback code.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS: Add a helper to return a pointer to the open context of a struct nfs_page

Add a helper for when we remove the explicit pointer to the open
context.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS: Fix a typo in pnfs_update_layout

We're supposed to wait for the outstanding layout count to go to zero,
but that got lost somehow.

Fixes: d03360aaf5cca ("pNFS: Ensure we return the error if someone...")
Reported-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS/pnfs: Bulk destroy of layouts needs to be safe w.r.t. umount

If a bulk layout recall or a metadata server reboot coincides with a
umount, then holding a reference to an inode is unsafe unless we
also hold a reference to the super block.

Fixes: fd9a8d7160937 ("NFSv4.1: Fix bulk recall and destroy of layouts")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.

SUNRPC has two sorts of credentials, both of which appear as
"struct rpc_cred".
There are "generic credentials" which are supplied by clients
such as NFS and passed in 'struct rpc_message' to indicate
which user should be used to authorize the request, and there
are low-level credentials such as AUTH_NULL, AUTH_UNIX, AUTH_GSS
which describe the credential to be sent over the wires.

This patch replaces all the generic credentials by 'struct cred'
pointers - the credential structure used throughout Linux.

For machine credentials, there is a special 'struct cred *' pointer
which is statically allocated and recognized where needed as
having a special meaning. A look-up of a low-level cred will
map this to a machine credential.

Signed-off-by: NeilBrown <neilb@suse.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFS: Convert lookups of the open context to RCU

Reduce contention on the inode->i_lock by ensuring that we use RCU
when looking up the NFS open context.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Don't allocate more pages than we need to fit a layoutget response

For the 'files' and 'flexfiles' layout types, we do not expect the reply
to be any larger than 4k. The block and scsi layout types are a little more
greedy, so we keep allocating the maximum response size for now.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Don't zero out the array in nfs4_alloc_pages()

We don't need a zeroed out array, since it is immediately being filled.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Ensure we return the error if someone kills a waiting layoutget

If someone interrupts a wait on one or more outstanding layoutgets in
pnfs_update_layout() then return the ERESTARTSYS/EINTR error.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS: Remove unwanted optimisation of layoutget

If we knew that the file was empty, we wouldn't be asking for a layout.
Any optimisation here is already done before calling pnfs_update_layout().
As it stands, we sometimes end up doing an unnecessary inband read to
the MDS even when holding a layout.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS: Treat RECALLCONFLICT like DELAY...

Yes, it is possible to get trapped in a loop, but the server should be
administratively revoking the recalled layout if it never gets returned.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS: When updating the stateid in layoutreturn, also update the recall range

When we update the layout stateid in nfs4_layoutreturn_refresh_stateid, we
should also update the range in order to let the server know we're actually
returning everything.

Fixes: 16c278dbfa63 ("pnfs: Fix handling of NFS4ERR_OLD_STATEID replies...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: Use true and false for boolean values

Return statements in functions returning bool should use true or false
instead of an integer value.

This issue was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: pnfs_find_lseg() should not check NFS_LSEG_LAYOUTRETURN

Layout segment validity is determined only by the NFS_LSEG_VALID flag. If
it is set, the layout segment is finable. As it is, when the flexfiles
driver sets NFS_LSEG_LAYOUTRETURN to indicate that we cannot discard
the layout segment, but that it must be returned, then this can result
in an unnecessary layoutget storm.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: Fix handling of NFS4ERR_OLD_STATEID replies to layoutreturn

If the server tells us that out layoutreturn raced with another layout
update, then we must ensure that the new layout segments are not in use
before we resend with an updated layout stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS: Parse the results of layoutget on open even if permissions checks fail

Even if the results of the permissions checks failed, we should parse
the results of the layout on open call so that we can return the
layout if required.
Note that we also want to ignore the sequence counter for whether or not
a layout recall occurred. If the recall pertained to our OPEN, then the
callback will know, and will attempt to wait for us to finih processing
anyway.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Wait for stale layoutget calls to complete in pnfs_update_layout()

If the old layout was recalled, and we returned NFS4ERR_NOMATCHINGLAYOUT
then we need to wait for all outstanding layoutget calls to complete
before we can send a new one.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Ignore non-recalled layouts in pnfs_layout_need_return()

If a layout has been recalled, then we should fire off a layoutreturn as
soon as all the layout segments that match the recall have been retired.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Don't discard layout segments that are marked for return

If there are layout segments that are marked for return, then we need
to ensure that pnfs_mark_matching_lsegs_return() does not just
silently discard them, but it should tell the caller that there is a
layoutreturn scheduled.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

skip LAYOUTRETURN if layout is invalid

Currently, when IO to DS fails, client returns the layout and
retries against the MDS. However, then on umounting (inode eviction)
it returns the layout again.

This is because pnfs_return_layout() was changed in
commit d78471d32bb6 ("pnfs/blocklayout: set PNFS_LAYOUTRETURN_ON_ERROR")
to always set NFS_LAYOUT_RETURN_REQUESTED so even if we returned
the layout, it will be returned again. Instead, let's also check
if we have already marked the layout invalid.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs: Don't call commit on failed layoutget-on-open

If the layoutget on open call failed, we can't really commit the inode,
so don't bother calling it.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Don't send LAYOUTGET on OPEN for read, if we already have cached data

If we're only opening the file for reading, and the file is empty and/or
we already have cached data, then heuristically optimise away the
LAYOUTGET.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4/pnfs: Don't switch off layoutget-on-open for transient errors

Ensure that we only switch off the LAYOUTGET operation in the OPEN
compound when the server is truly broken, and/or it is complaining
that the compound is too large.
Currently, we end up turning off the functionality permanently,
even for transient errors such as EACCES or ENOSPC.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSv4/pnfs: Ensure pnfs_parse_lgopen() won't try to parse uninitialised data

We need to ensure that pnfs_parse_lgopen() doesn't try to parse a
struct nfs4_layoutget_res that was not filled by a successful call
to decode_layoutget(). This can happen if we performed a cached open,
or if either the OP_ACCESS or OP_GETATTR operations preceding the
OP_LAYOUTGET in the compound returned an error.

By initialising the 'status' field to NFS4ERR_DELAY, we ensure that
pnfs_parse_lgopen() won't try to interpret the structure.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs: Fix manipulation of NFS_LAYOUT_FIRST_LAYOUTGET

The flag was not always being cleared after LAYOUTGET on OPEN.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs: Add barrier to prevent lgopen using LAYOUTGET during recall

Since the LAYOUTGET on OPEN can be sent without prior inode information,
existing methods to prevent LAYOUTGET from being sent while processing
CB_LAYOUTRECALL don't work. Track if a recall occurred while LAYOUTGET
was being sent, and if so ignore the results.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs: Stop attempting LAYOUTGET on OPEN on failure

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs: Add LAYOUTGET to OPEN of an existing file

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Refactor nfs4_layoutget_release()

Move the actual freeing of the struct nfs4_layoutget into fs/nfs/pnfs.c
where it can be reused by the layoutget on open code.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs: Add LAYOUTGET to OPEN of a new file

This triggers when have no pre-existing inode to attach to.
The preexisting case is saved for later.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs: Change pnfs_alloc_init_layoutget_args call signature

Don't send in a layout, instead use the (possibly NULL) inode.

This is needed for LAYOUTGET attached to an OPEN where the inode is not
yet set.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs: Move nfs4_opendata into nfs4_fs.h

It will be needed now by the pnfs code.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs: move allocations out of nfs4_proc_layoutget

They work better in the new alloc_init function.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pnfs: refactor send_layoutget

Pull out the alloc/init part for eventual reuse by OPEN.

Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

pNFS: Prevent the layout header refcount going to zero in pnfs_roc()

Ensure that we hold a reference to the layout header when processing
the pNFS return-on-close so that the refcount value does not inadvertently
go to zero.

Reported-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.10+
Tested-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>

nfs/pnfs: fix nfs_direct_req ref leak when i/o falls back to the mds

Currently when falling back to doing I/O through the MDS (via
pnfs_{read|write}_through_mds), the client frees the nfs_pgio_header
without releasing the reference taken on the dreq
via pnfs_generic_pg_{read|write}pages -> nfs_pgheader_init ->
nfs_direct_pgio_init. It then takes another reference on the dreq via
nfs_generic_pg_pgios -> nfs_pgheader_init -> nfs_direct_pgio_init and
as a result the requester will become stuck in inode_dio_wait. Once
that happens, other processes accessing the inode will become stuck as
well.

Ensure that pnfs_read_through_mds() and pnfs_write_through_mds() clean
up correctly by calling hdr->completion_ops->completion() instead of
calling hdr->release() directly.

This can be reproduced (sometimes) by performing "storage failover
takeover" commands on NetApp filer while doing direct I/O from a client.

This can also be reproduced using SystemTap to simulate a failure while
doing direct I/O from a client (from Dave Wysochanski
<dwysocha@redhat.com>):

stap -v -g -e 'probe module("nfs_layout_nfsv41_files").function("nfs4_fl_prepare_ds").return { $return=NULL; exit(); }'

Suggested-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Fixes: 1ca018d28d ("pNFS: Fix a memory leak when attempted pnfs fails")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pnfs/blocklayout: handle transient devices

PNFS block/SCSI layouts should gracefully handle cases where block devices
are not available when a layout is retrieved, or the block devices are
removed while the client holds a layout.

While setting up a layout segment, keep a record of an unavailable or
un-parsable block device in cache with a flag so that subsequent layouts do
not spam the server with GETDEVINFO. We can reuse the current
NFS_DEVICEID_UNAVAILABLE handling with one variation: instead of reusing
the device, we will discard it and send a fresh GETDEVINFO after the
timeout, since the lookup and validation of the device occurs within the
GETDEVINFO response handling.

A lookup of a layout segment that references an unavailable device will
return a segment with the NFS_LSEG_UNAVAILABLE flag set. This will allow
the pgio layer to mark the layout with the appropriate fail bit, which
forces subsequent IO to the MDS, and prevents spamming the server with
LAYOUTGET, LAYOUTRETURN.

Finally, when IO to a block device fails, look up the block device(s)
referenced by the pgio header, and mark them as unavailable.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS: Retry NFS4ERR_OLD_STATEID errors in layoutreturn-on-close

If our layoutreturn on close operation returns an NFS4ERR_OLD_STATEID,
then try to update the stateid and retry. We know that there should
be no further LAYOUTGET requests being launched.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFS: Fix bool initialization/comparison

Bool initializations should use true and false. Bool tests don't need
comparisons.

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs, nfs: convert pnfs_layout_hdr.plh_refcount from atomic_t to refcount_t

atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)

Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.

The variable pnfs_layout_hdr.plh_refcount is used as pure reference counter.
Convert it to refcount_t and fix up the operations.

Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs, nfs: convert pnfs_layout_segment.pls_refcount from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS: Use the standard I/O stateid when calling LAYOUTGET

Instead of having a private method for copying the open/delegation stateid,
use the same call that is used for standard I/O through the MDS.

Note that this means we transmit the stateid with a zero seqid, avoiding
issues with NFS4ERR_OLD_STATEID.

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

NFS: Fix 2 use after free issues in the I/O code

The writeback code wants to send a commit after processing the pages,
which is why we want to delay releasing the struct path until after
that's done.

Also, the layout code expects that we do not free the inode before
we've put the layout segments in pnfs_writehdr_free() and
pnfs_readhdr_free()

Fixes: 919e3bd9a875 ("NFS: Ensure we commit after writeback is complete")
Fixes: 4714fb51fd03 ("nfs: remove pgio_header refcount, related cleanup")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4/pnfs: Replace pnfs_put_lseg_locked() with pnfs_put_lseg()

Now that we no longer hold the inode->i_lock when manipulating the
commit lists, it is safe to call pnfs_put_lseg() again.

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

pnfs: Fix the check for requests in range of layout segment

It's possible and acceptable for NFS to attempt to add requests beyond the
range of the current pgio->pg_lseg, a case which should be caught and
limited by the pg_test operation. However, the current handling of this
case replaces pgio->pg_lseg with a new layout segment (after a WARN) within
that pg_test operation. That will cause all the previously added requests
to be submitted with this new layout segment, which may not be valid for
those requests.

Fix this problem by only returning zero for the number of bytes to coalesce
from pg_test for this case which allows any previously added requests to
complete on the current layout segment. The check for requests starting
out of range of the layout segment moves to pg_init, so that the
replacement of pgio->pg_lseg will be done when the next request is added.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS: Fix a deadlock when coalescing writes and returning the layout

Consider the following deadlock:

Process P1 Process P2 Process P3
========== ========== ==========
lock_page(page)

lseg = pnfs_update_layout(inode)

lo = NFS_I(inode)->layout
pnfs_error_mark_layout_for_return(lo)

lock_page(page)

lseg = pnfs_update_layout(inode)

In this scenario,
- P1 has declared the layout to be in error, but P2 holds a reference to
a layout segment on that inode, so the layoutreturn is deferred.
- P2 is waiting for a page lock held by P3.
- P3 is asking for a new layout segment, but is blocked waiting
for the layoutreturn.

The fix is to ensure that pnfs_error_mark_layout_for_return() does
not set the NFS_LAYOUT_RETURN flag, which blocks P3. Instead, we allow
the latter to call LAYOUTGET so that it can make progress and unblock
P2.

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

pNFS: Don't clear the layout return info if there are segments to return

In pnfs_clear_layoutreturn_info, ensure that we don't clear the layout
return info if there are new segments queued for return due to, for
instance, a race between a LAYOUTRETURN and a failed I/O attempt.

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

pNFS: Ensure we commit the layout if it has been invalidated

If the layout is being invalidated on the server, then we must
invoke nfs_commit_inode() to ensure any commits to the DS get
cleared out.

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

pNFS/flexfiles: Fix up the ff_layout_write_pagelist failure path

If the attempt to write through pNFS fails, we need to use the same
failure semantics as for the read path: If the FF_FLAGS_NO_IO_THRU_MDS
flag is set or we have sufficient valid DSes, then we must retry through
pNFS

Fixes: d67ae825a59d ("pnfs/flexfiles: Add the FlexFile Layout Driver")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS: Ensure we check layout validity before marking it for return

pnfs_error_mark_layout_for_return needs to check that the layout is
valid before calling pnfs_set_plh_return_info().

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

pNFS: Fix use after free issues in pnfs_do_read()

The assumption should be that if the caller returns PNFS_ATTEMPTED, then hdr
has been consumed, and so we should not be testing hdr->task.tk_status.
If the caller returns PNFS_TRY_AGAIN, then we need to recoalesce and
free hdr.

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

pNFS: Ensure we check layout segment validity in the pg_init() callback

If we have a layout segment cached in pgio->pg_lseg, we should check it
for validity before reusing it in a new RPC request. Otherwise, if we
recoalesce, we can end up looping forever.

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

pNFS: Unexport pnfs_put_lseg_locked and _pnfs_return_layout

They are not used outside the NFSv4 module.

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

pNFS: Fix a reference leak in _pnfs_return_layout

IF NFS_LAYOUT_RETURN_REQUESTED is not set, then we currently exit
without freeing the list of invalidated layout segments, leading
to a reference leak.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: 24408f5282 ("pNFS: Fix bugs in _pnfs_return_layout")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS: Return RW layouts on OPEN_DOWNGRADE

If the client holds no more writeable open state, and does not hold a
write delegation, then send a layoutreturn as part of the OPEN_DOWNGRADE.

We do this only for writes, since some layout drivers may require you to
also hold a read layout if you are doing a R/W workload.

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

pNFS: Release NFS_LAYOUT_RETURN when invalidating the layout stateid

Ensure we release the NFS_LAYOUT_RETURN lock when we invalidate the
layout stateid, so that processes and RPC tasks that are waiting on
the layout return can continue.

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

pNFS: Add a layoutreturn callback to performa layout-private setup

Add a callback to allow the flexfiles layout driver to initialise the
layout private payload.

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

pNFS: Allow layout drivers to manage private data in struct nfs4_layoutreturn

Cleanup to allow layout drivers to attach private data to layoutreturn,
and manage the data.

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

pNFS: Skip invalid stateids when doing a bulk destroy

If the layout stateid is already invalid, we have no work to do.

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

pNFS: Wait on outstanding layoutreturns to complete in pnfs_roc()

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

pNFS: Don't mark the layout as freed if the last lseg is marked for return

Address another memory leak.

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

pNFS: Sync the layout state bits in pnfs_cache_lseg_for_layoutreturn

Ensure that the layout state bits are synced when we cache a layout
segment for layoutreturn using an appropriate call to
pnfs_set_plh_return_info.

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

pNFS: Fix bugs in _pnfs_return_layout

We need to honour the NFS_LAYOUT_RETURN_REQUESTED bit regardless of
whether or not there are layout segments pending.
Furthermore, we should ensure that we leave the plh_return_segs list
empty.

This patch fixes a memory leak of the layout segments on plh_return_segs.

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

pNFS: Clear all layout segment state in pnfs_mark_layout_stateid_invalid

When the layout state is invalidated, then so is the layout segment
state, and hence we do need to clean up the state bits.

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

pNFS: Enable layoutreturn operation for return-on-close

Amend the pnfs return on close helper functions to enable sending the
layoutreturn op in CLOSE/DELEGRETURN. This closes a potential race between
CLOSE/DELEGRETURN and parallel OPEN calls to the same file, and allows the
client and the server to agree on whether or not there is an outstanding
layout.

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

pNFS: Clean up - add a helper to initialise struct layoutreturn_args

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

pNFS: Don't mark layout segments invalid on layoutreturn in pnfs_roc

The layoutreturn call will take care of invalidating the layout segments
once the call is successful.

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

pNFS: Skip checking for return-on-close if the layout is invalid

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

pNFS: Remove spurious wake up in pnfs_layout_remove_lseg()

There is no change to the value of NFS_LAYOUT_RETURN, so we should
not be waking up the RPC call.

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

NFSv4: Ignore LAYOUTRETURN result if the layout doesn't match or is invalid

Fix a potential race with CB_LAYOUTRECALL in which the server recalls the
remaining layout segments while our LAYOUTRETURN is still in transit.

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

pNFS: Do not free layout segments that are marked for return

We may want to process and transmit layout stat information for the
layout segments that are being returned, so we should defer freeing
them until after the layoutreturn has completed.

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

pNFS: consolidate the different range intersection tests

Both pnfs.c and the flexfiles code have their own versions of the
range intersection testing, and the "end_offset" helper.

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

pNFS: Fix race in pnfs_wait_on_layoutreturn

We must put the task to sleep while holding the inode->i_lock in order
to ensure atomicity with the test for NFS_LAYOUT_RETURN.

Fixes: 500d701f336b ("NFS41: make close wait for layoutreturn")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS: On error, do not send LAYOUTGET until the LAYOUTRETURN has completed

If there is an I/O error, we should not call LAYOUTGET until the
LAYOUTRETURN that reports the error is complete.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.8+

pNFS: Force a retry of LAYOUTGET if the stateid doesn't match our cache

If the server sends us a completely new stateid, and the client thinks
it already holds a layout, then force a retry of the LAYOUTGET after
invalidating the existing layout in order to avoid corruption due to
races.

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

pNFS: Clear NFS_LAYOUT_RETURN_REQUESTED when invalidating the layout stateid

We must ensure that we don't schedule a layoutreturn if the layout stateid
has been marked as invalid.

Fixes: 2a59a0411671e ("pNFS: Fix pnfs_set_layout_stateid() to clear...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.8+

pNFS: Don't clear the layout stateid if a layout return is outstanding

If we no longer hold any layout segments, we're normally expected to
consider the layout stateid to be invalid. However we cannot assume this
if we're about to, or in the process of sending a layoutreturn.

Fixes: 334a8f37115b ("pNFS: Don't forget the layout stateid if...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.8+

pNFS: Fix a deadlock between read resends and layoutreturn

We must not call nfs_pageio_init_read() on a new nfs_pageio_descriptor
while holding a reference to a layout segment, as that can deadlock
pnfs_update_layout().

Fixes: d67ae825a59d6 ("pnfs/flexfiles: Add the FlexFile Layout Driver")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.0+

NFS: Don't print a pNFS error if we aren't using pNFS

We used to check for a valid layout type id before verifying pNFS flags
as an indicator for if we are using pNFS. This changed in 3132e49ece
with the introduction of multiple layout types, since now we are passing
an array of ids instead of just one. Since then, users have been seeing
a KERN_ERR printk show up whenever mounting NFS v4 without pNFS. This
patch restores the original behavior of exiting set_pnfs_layoutdriver()
early if we aren't using pNFS.

Fixes 3132e49ece ("pnfs: track multiple layout types in fsinfo
structure")
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS: Fix atime updates on pNFS clients

Fix the code so that we always mark the atime as invalid in nfs4_read_done().
Currently, the expectation appears to be that the pNFS drivers should always
do this, with the result that most of them don't.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: add a new mechanism to select a layout driver according to an ordered list

Currently, the layout driver selection code always chooses the first one
from the list. That's not really ideal however, as the server can send
the list of layout types in any order that it likes. It's up to the
client to select the best one for its needs.

This patch adds an ordered list of preferred driver types and has the
selection code sort the list of available layout drivers according to it.
Any unrecognized layout type is sorted to the end of the list.

For now, the order of preference is hardcoded, but it should be possible
to make this configurable in the future.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: track multiple layout types in fsinfo structure

Current NFSv4.1/pNFS client assumes that MDS supports only one layout
type. While it's true for most existing servers, nevertheless, this can
be change in the near future.

For now, this patch just plumbs in the ability to track a list of
layouts in the fsinfo structure. The existing behavior of the client
is preserved, by having it just select the first entry in the list.

Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
Reviewed-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS: Don't forget the layout stateid if there are outstanding LAYOUTGETs

If there are outstanding LAYOUTGET rpc calls, then we want to ensure that
we keep the layout stateid around so we that don't inadvertently pick up
an old/misordered sequence id.
The race is as follows:

Client Server
====== ======
LAYOUTGET(seqid)
LAYOUTGET(seqid)
return LAYOUTGET(seqid+1)
return LAYOUTGET(seqid+2)
process LAYOUTGET(seqid+2)
forget layout
process LAYOUTGET(seqid+1)

If it forgets the layout stateid before processing seqid+1, then
the client will not check the layout->plh_barrier, and so will set
the stateid with seqid+1.

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

pNFS: Fix pnfs_set_layout_stateid() to clear NFS_LAYOUT_INVALID_STID

If the layout was marked as invalid, we want to ensure to initialise
the layout header fields correctly.

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

pNFS: Ensure LAYOUTGET and LAYOUTRETURN are properly serialised

According to RFC5661, the client is responsible for serialising
LAYOUTGET and LAYOUTRETURN to avoid ambiguity. Consider the case
where we send both in parallel.

Client Server
====== ======
LAYOUTGET(seqid=X)
LAYOUTRETURN(seqid=X)
LAYOUTGET return seqid=X+1
LAYOUTRETURN return seqid=X+2
Process LAYOUTRETURN
Forget layout stateid
Process LAYOUTGET
Set seqid=X+1

The client processes the layoutget/layoutreturn in the wrong order,
and since the result of the layoutreturn was to clear the only
existing layout segment, the client forgets the layout stateid.

When the LAYOUTGET comes in, it is treated as having a completely
new stateid, and so the client sets the wrong sequence id...

Fix is to check if there are outstanding LAYOUTGET requests
before we send the LAYOUTRETURN (note that LAYOUGET will already
wait if it sees an outstanding LAYOUTRETURN).

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.5+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS: The client must not do I/O to the DS if it's lease has expired

Ensure that the client conforms to the normative behaviour described in
RFC5661 Section 12.7.2: "If a client believes its lease has expired,
it MUST NOT send I/O to the storage device until it has validated its
lease."

So ensure that we wait for the lease to be validated before using
the layout.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v3.20+

pNFS: Handle NFS4ERR_OLD_STATEID correctly in LAYOUTSTAT calls

We normally want to update the stateid and then retry,

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

pNFS: Remove redundant smp_mb() from pnfs_init_lseg()

It's not visible yet, and won't be until after we grab the inode->i_lock.

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

pNFS: Cleanup - do layout segment initialisation in one place

...instead of splitting the initialisation over init_lseg() and
pnfs_layout_process().

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

pNFS: Remove redundant stateid invalidation

The layout stateid will be invalidated once it holds no more layout
segments anyway.

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

pNFS: Remove redundant pnfs_mark_layout_returned_if_empty()

That's already being taken care of in pnfs_layout_remove_lseg().

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

pNFS: Clear the layout metadata if the server changed the layout stateid

If the server changed the layout stateid's "other" field, then
we should treat the old layout as being completely gone. In that
case, we want to clear the metadata such as scheduled layoutreturns.

Do this by calling pnfs_mark_layout_stateid_invalid().

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

pNFS: Cleanup - don't open code pnfs_mark_layout_stateid_invalid()

Ensure nfs42_layoutstat_done() layoutget don't open code layout stateid
invalidation.

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

NFS: pnfs_mark_matching_lsegs_return() should match the layout sequence id

When determining which layout segments to return, we do want
pnfs_mark_matching_lsegs_return to check that they match the layout
sequence id. This ensures that we don't waste time if the server
is replaying a layout recall that has already been satisfied.

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

pNFS: Do not set plh_return_seq for non-callback related layoutreturns

In cases where we need to send a layoutreturn in order to propagate
an error, we should not tie that to a specific layout stateid.

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

pNFS: Ensure layoutreturn acts as a completion for layout callbacks

When we return NFS_OK to the CB_LAYOUTRECALL, we are required to
send a layoutreturn that "completes" that layout recall request, using
the correct stateid.

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

pNFS: Always update the layout barrier seqid on LAYOUTGET

Currently, pnfs_set_layout_stateid() will update the layout sequence
id barrier only if the stateid itself is newer than the current
layout stateid. However in a situation where multiple LAYOUTGET calls
and a LAYOUTRETURN raced, it is entirely possible for one of the
LAYOUTGET to set the current stateid to something newer than the
LAYOUTRETURN that needs to set the barrier.

The fix is to allow the "update_barrier" flag to force a check as to
whether or not the barrier needs to be updated.

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

pNFS: Always update the layout stateid if NFS_LAYOUT_INVALID_STID is set

If the layout stateid is invalid, then pnfs_set_layout_stateid() must
always initialise it.

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

pNFS: Clear the layout return tracking on layout reinitialisation

Ensure that we don't carry over layoutreturn info from a previous
incarnation of this layout.

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

pNFS: Handle NFS4ERR_RECALLCONFLICT correctly in LAYOUTGET

Instead of giving up altogether and falling back to doing I/O
through the MDS, which may make the situation worse, wait for
2 lease periods for the callback to resolve itself, and then
try destroying the existing layout.

Only if this was an attempt at getting a first layout, do we
give up altogether, as the server is clearly crazy.

Fixes: 183d9e7b112aa ("pnfs: rework LAYOUTGET retry handling")
Cc: stable@vger.kernel.org # 4.7
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>

pNFS: Separate handling of NFS4ERR_LAYOUTTRYLATER and RECALLCONFLICT

They are not the same error, and need to be handled differently.

Fixes: 183d9e7b112aa ("pnfs: rework LAYOUTGET retry handling")
Cc: stable@vger.kernel.org # 4.7
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>

pNFS: Fix post-layoutget error handling in pnfs_update_layout()

The non-retry error path is currently broken and ends up releasing the
reference to the layout twice. It also can end up clearing the
NFS_LAYOUT_FIRST_LAYOUTGET flag twice, causing a race.

In addition, the retry path will fail to decrement the plh_outstanding
counter.

Fixes: 183d9e7b112aa ("pnfs: rework LAYOUTGET retry handling")
Cc: stable@vger.kernel.org # 4.7
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>

pNFS: Files and flexfiles always need to commit before layoutcommit

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

Note that by doing this, we're able to optimise away the commit
for the case of servers that don't need layoutcommit in order to
return updated attributes.

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

NFSv4.1/pnfs: Mark the layout stateid invalid when all segments are removed

According to RFC5661, section 12.5.3. the layout stateid is no longer
valid once the client no longer holds any layout segments. Ensure that
we mark it invalid.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4.1/pnfs: Add sparse lock annotations for pnfs_find_alloc_layout

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

NFSv4.1/pnfs: Layout stateids start out as being invalid

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: pnfs_update_layout needs to consider if strict iomode checking is on

As flexfiles has FF_FLAGS_NO_READ_IO, there is a need to generically
support enforcing that a IOMODE_RW segment will not allow READ I/O.

Signed-off-by: Tom Haynes <loghyr@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: make pnfs_layout_process more robust

It can return NULL if layoutgets are blocked currently. Fix it to return
-EAGAIN in that case, so we can properly handle it in pnfs_update_layout.

Also, clean up and simplify the error handling -- eliminate "status" and
just use "lseg".

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: rework LAYOUTGET retry handling

There are several problems in the way a stateid is selected for a
LAYOUTGET operation:

We pick a stateid to use in the RPC prepare op, but that makes
it difficult to serialize LAYOUTGETs that use the open stateid. That
serialization is done in pnfs_update_layout, which occurs well before
the rpc_prepare operation.

Between those two events, the i_lock is dropped and reacquired.
pnfs_update_layout can find that the list has lsegs in it and not do any
serialization, but then later pnfs_choose_layoutget_stateid ends up
choosing the open stateid.

This patch changes the client to select the stateid to use in the
LAYOUTGET earlier, when we're searching for a usable layout segment.
This way we can do it all while holding the i_lock the first time, and
ensure that we serialize any LAYOUTGET call that uses a non-layout
stateid.

This also means a rework of how LAYOUTGET replies are handled, as we
must now get the latest stateid if we want to retransmit in response
to a retryable error.

Most of those errors boil down to the fact that the layout state has
changed in some fashion. Thus, what we really want to do is to re-search
for a layout when it fails with a retryable error, so that we can avoid
reissuing the RPC at all if possible.

While the LAYOUTGET RPC is async, the initiating thread always waits for
it to complete, so it's effectively synchronous anyway. Currently, when
we need to retry a LAYOUTGET because of an error, we drive that retry
via the rpc state machine.

This means that once the call has been submitted, it runs until it
completes. So, we must move the error handling for this RPC out of the
rpc_call_done operation and into the caller.

In order to handle errors like NFS4ERR_DELAY properly, we must also
pass a pointer to the sliding timeout, which is now moved to the stack
in pnfs_update_layout.

The complicating errors are -NFS4ERR_RECALLCONFLICT and
-NFS4ERR_LAYOUTTRYLATER, as those involve a timeout after which we give
up and return NULL back to the caller. So, there is some special
handling for those errors to ensure that the layers driving the retries
can handle that appropriately.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: lift retry logic from send_layoutget to pnfs_update_layout

If we get back something like NFS4ERR_OLD_STATEID, that will be
translated into -EAGAIN, and the do/while loop in send_layoutget
will drive the call again.

This is not quite what we want, I think. An error like that is a
sign that something has changed. That something could have been a
concurrent LAYOUTGET that would give us a usable lseg.

Lift the retry logic into pnfs_update_layout instead. That allows
us to redo the layout search, and may spare us from having to issue
an RPC.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: fix bad error handling in send_layoutget

Currently, the code will clear the fail bit if we get back a fatal
error. I don't think that's correct -- we want to clear that bit
if we do not get a fatal error.

Fixes: 0bcbf039f6 (nfs: handle request add failure properly)
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: only tear down lsegs that precede seqid in LAYOUTRETURN args

LAYOUTRETURN is "special" in that servers and clients are expected to
work with old stateids. When the client sends a LAYOUTRETURN with an old
stateid in it then the server is expected to only tear down layout
segments that were present when that seqid was current. Ensure that the
client handles its accounting accordingly.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: keep track of the return sequence number in pnfs_layout_hdr

When we want to selectively do a LAYOUTRETURN, we need to specify a
stateid that represents most recent layout acquisition that is to be
returned.

When we mark a layout stateid to be returned, we update the return
sequence number in the layout header with that value, if it's newer
than the existing one. Then, when we go to do a LAYOUTRETURN on
layout header put, we overwrite the seqid in the stateid with the
saved one, and then zero it out.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: record sequence in pnfs_layout_segment when it's created

In later patches, we're going to teach the client to be more selective
about how it returns layouts. This means keeping a record of what the
stateid's seqid was at the time that the server handed out a layout
segment.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pNFS: Fix a leaked layoutstats flag

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs: set NFS_IOHDR_REDO in pnfs_read_resend_pnfs

Like other resend paths, mark the (old) hdr as NFS_IOHDR_REDO. This
ensures the hdr completion function will not count the (old) hdr
as good bytes.

Also, vector the error back through the hdr->task.tk_status like other
retry calls.

This fixes a bug with the FlexFiles layout where libaio was reporting more
bytes read than requested.

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized. And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special. They are
not.

The changes are pretty straight-forward:

- <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

- <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

- PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

- page_cache_get() -> get_page();

- page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below. For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach. I'll
fix them manually in a separate patch. Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

NFSv4.x/pnfs: Fix a race between layoutget and bulk recalls

Replace another case where the layout 'plh_block_lgets' can trigger
infinite loops in send_layoutget().

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

NFSv4.x/pnfs: Fix a race between layoutget and pnfs_destroy_layout

If the server reboots while there is a layoutget outstanding, then
the call to pnfs_choose_layoutget_stateid() will fail with an EAGAIN
error, which causes an infinite loop in send_layoutget(). The reason
why we never break out of the loop is that the layout 'plh_block_lgets'
field is never cleared.

Fix is to replace plh_block_lgets with NFS_LAYOUT_INVALID_STID, which
can be reset after a new layoutget.

Fixes: ab7d763e477c5 ("pNFS: Ensure nfs4_layoutget_prepare returns...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS: Always set NFS_LAYOUT_RETURN_REQUESTED with lo->plh_return_iomode

When setting the layout return mode, we must always also set the
NFS_LAYOUT_RETURN_REQUESTED flag to ensure that we send a layoutreturn.
Otherwise pnfs_error_mark_layout_for_return() could set the mode, but
fail to send the layoutreturn because another is already in flight.

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

pNFS: Fix pnfs_mark_matching_lsegs_return()

We don't need to schedule a layoutreturn if the layout segment can
be freed immediately.

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

NFS: Cleanup - rename NFS_LAYOUT_RETURN_BEFORE_CLOSE

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: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS: Fix missing layoutreturn calls

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: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1/pNFS: Cleanup constify struct pnfs_layout_range arguments

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

NFSv4.1/pnfs: Cleanup copying of pnfs_layout_range structures

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

NFSv4.1/pNFS: Cleanup pnfs_mark_matching_lsegs_invalid()

Make it more obvious what we're returning...

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

NFSv4.1/pNFS: pnfs_error_mark_layout_for_return() must always return layout

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: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1/pNFS: pnfs_mark_matching_lsegs_return() should set the iomode

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: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1/pNFS: Use nfs4_stateid_copy for copying stateids

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

NFSv4.1/pNFS: Don't pass stateids by value to pnfs_send_layoutreturn()

A stateid is a structure, pass it as a pointer.

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

NFSv4.1/pNFS: Don't queue up a new commit if the layout segment is invalid

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: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS: If we have to delay the layout callback, mark the layout for return

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: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1/pNFS: Add a helper to mark the layout as returned

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: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS/flexfiles: Don't mark the entire layout as failed, when returning it

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: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS/flexfiles: Don't prevent flexfiles client from retrying LAYOUTGET

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: Trond Myklebust <trond.myklebust@primarydata.com>

nfs: handle request add failure properly

When we fail to queue a read page to IO descriptor,
we need to clean it up otherwise it is hanging around
preventing nfs module from being removed.

When we fail to queue a write page to IO descriptor,
we need to clean it up and also save the failure status
to open context. Then at file close, we can try to write
pages back again and drop the page if it fails to writeback
in .launder_page, which will be done in the next patch.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs: centralize pgio error cleanup

In case we fail during setting things up for read/write IO, set
pg_error in IO descriptor and do the cleanup in nfs_pageio_add_request,
where we clean up all pages that are still hanging around on the IO
descriptor.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFS41: pop some layoutget errors to application

For ERESTARTSYS/EIO/EROFS/ENOSPC/E2BIG in layoutget, we
should just bail out instead of hiding the error and
retrying inband IO.

Change all the call sites to pop the error all the way up.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS: Modify pnfs_update_layout tracepoints to use layout stateid

Instead of displaying a layout segment pointer in these tracepoints,
let's use the layout stateid, now that Olga gave us a set of tools for
displaying them.

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

nfs: add new tracepoint for pnfs_update_layout

pnfs_update_layout is really the "nexus" of layout handling. If it
returns NULL then we end up going through the MDS. This patch adds
some tracepoints to that function that allow us to determine the
cause when we end up going through the MDS unexpectedly.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sched/wait: Fix the signal handling fix

Jan Stancek reported that I wrecked things for him by fixing things for
Vladimir :/

His report was due to an UNINTERRUPTIBLE wait getting -EINTR, which
should not be possible, however my previous patch made this possible by
unconditionally checking signal_pending().

We cannot use current->state as was done previously, because the
instruction after the store to that variable it can be changed. We must
instead pass the initial state along and use that.

Fixes: 68985633bccb ("sched/wait: Fix signal handling in bit wait helpers")
Reported-by: Jan Stancek <jstancek@redhat.com>
Reported-by: Chris Mason <clm@fb.com>
Tested-by: Jan Stancek <jstancek@redhat.com>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com>
Tested-by: Chris Mason <clm@fb.com>
Reviewed-by: Paul Turner <pjt@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: tglx@linutronix.de
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: hpa@zytor.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nfs4: resend LAYOUTGET when there is a race that changes the seqid

pnfs_layout_process will check the returned layout stateid against what
the kernel has in-core. If it turns out that the stateid we received is
older, then we should resend the LAYOUTGET instead of falling back to
MDS I/O.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Cc: stable@vger.kernel.org # 3.18+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1/pnfs: Retry through MDS when getting bad length of data

If non rpc-based layout driver return bad length of data, nfs retries
by calling rpc_restart_call_prepare() that cause an NULL reference panic.

This patch lets nfs retry through MDS for non rpc-based layout driver
return bad length of data.

[13034.883329] BUG: unable to handle kernel NULL pointer dereference at (null)
[13034.884902] IP: [<ffffffffa00db372>] rpc_restart_call_prepare+0x62/0x90 [sunrpc]
[13034.886558] PGD 0
[13034.888126] Oops: 0000 [#1] KASAN
[13034.889710] Modules linked in: blocklayoutdriver(OE) nfsv4(OE) nfs(OE) fscache(E) nfsd(OE) xfs libcrc32c coretemp btrfs crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel ppdev vmw_balloon auth_rpcgss shpchp nfs_acl lockd vmw_vmci parport_pc xor raid6_pq grace parport sunrpc i2c_piix4 vmwgfx drm_kms_helper ttm drm mptspi e1000 serio_raw scsi_transport_spi mptscsih mptbase ata_generic pata_acpi [last unloaded: fscache]
[13034.898260] CPU: 0 PID: 10112 Comm: kworker/0:1 Tainted: G OE 4.3.0-rc5+ #279
[13034.899932] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/02/2015
[13034.903342] Workqueue: events bl_read_cleanup [blocklayoutdriver]
[13034.905059] task: ffff88006a9148c0 ti: ffff880035e90000 task.ti: ffff880035e90000
[13034.906827] RIP: 0010:[<ffffffffa00db372>] [<ffffffffa00db372>] rpc_restart_call_prepare+0x62/0x90 [sunrpc]
[13034.910522] RSP: 0018:ffff880035e97b58 EFLAGS: 00010282
[13034.912378] RAX: fffffbfff04a5a94 RBX: ffff880068fe4858 RCX: 0000000000000003
[13034.914339] RDX: dffffc0000000000 RSI: 0000000000000003 RDI: 0000000000000282
[13034.916236] RBP: ffff880035e97b68 R08: 0000000000000001 R09: 0000000000000001
[13034.918229] R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
[13034.920007] R13: ffff880068fe4858 R14: ffff880068fe4a60 R15: 0000000000001000
[13034.921845] FS: 0000000000000000(0000) GS:ffffffff82247000(0000) knlGS:0000000000000000
[13034.923645] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[13034.925525] CR2: 0000000000000000 CR3: 00000000063dd000 CR4: 00000000001406f0
[13034.932808] Stack:
[13034.934813] ffff880068fe4780 0000000000001000 ffff880035e97ba8 ffffffffa08800d2
[13034.936675] ffffffffa088029d ffff880068fe4780 ffff880068fe4858 ffffffffa089c0a0
[13034.938593] ffff880068fe47e0 ffff88005d59faf0 ffff880035e97be0 ffffffffa087e08f
[13034.940454] Call Trace:
[13034.942388] [<ffffffffa08800d2>] nfs_readpage_result+0x112/0x200 [nfs]
[13034.944317] [<ffffffffa088029d>] ? nfs_readpage_done+0xdd/0x160 [nfs]
[13034.946267] [<ffffffffa087e08f>] nfs_pgio_result+0x9f/0x120 [nfs]
[13034.948166] [<ffffffffa09266cc>] pnfs_ld_read_done+0x7c/0x1e0 [nfsv4]
[13034.950247] [<ffffffffa03b07ee>] bl_read_cleanup+0x2e/0x60 [blocklayoutdriver]
[13034.952156] [<ffffffff810ebf62>] process_one_work+0x412/0x870
[13034.954102] [<ffffffff810ebe84>] ? process_one_work+0x334/0x870
[13034.955949] [<ffffffff810ebb50>] ? queue_delayed_work_on+0x40/0x40
[13034.957985] [<ffffffff810ec441>] worker_thread+0x81/0x6a0
[13034.959817] [<ffffffff810ec3c0>] ? process_one_work+0x870/0x870
[13034.961785] [<ffffffff810f43bd>] kthread+0x17d/0x1a0
[13034.963544] [<ffffffff810f4240>] ? kthread_create_on_node+0x330/0x330
[13034.965479] [<ffffffff81100428>] ? finish_task_switch+0x88/0x220
[13034.967223] [<ffffffff810f4240>] ? kthread_create_on_node+0x330/0x330
[13034.968929] [<ffffffff81b6ae5f>] ret_from_fork+0x3f/0x70
[13034.970534] [<ffffffff810f4240>] ? kthread_create_on_node+0x330/0x330
[13034.972176] Code: c7 43 50 40 84 0d a0 e8 3d fe 1c e1 48 8d 7b 58 c7 83 e4 00 00 00 00 00 00 00 e8 ca fe 1c e1 4c 8b 63 58 4c 89 e7 e8 be fe 1c e1 <49> 83 3c 24 00 74 12 48 c7 43 50 f0 a2 0e a0 b8 01 00 00 00 5b
[13034.977148] RIP [<ffffffffa00db372>] rpc_restart_call_prepare+0x62/0x90 [sunrpc]
[13034.978780] RSP <ffff880035e97b58>
[13034.980399] CR2: 0000000000000000

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFS41: make close wait for layoutreturn

If we send a layoutreturn asynchronously before close, the close
might reach server first and layoutreturn would fail with BADSTATEID
because there is nothing keeping the layout stateid alive.

Also do not pretend sending layoutreturn if we are not.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1/pNFS: Don't request a minimal read layout beyond the end of file

If we have a read layout, then sanity check the minimal layout length
so that it does not extend beyond the end of file.

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

NFSv4.1/pnfs: Don't ask for a read layout for an empty file.

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

NFSv4.1/pNFS: pnfs_mark_matching_lsegs_return must notify of layout return

It's not sufficient to just mark the layout segment for layout return. We
also need to set the NFS_LAYOUT_RETURN_BEFORE_CLOSE flag in the layout header.

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

NFSv4.1/pnfs: Allow pNFS device drivers to customise layout segment insertion

This is needed in order to allow merging of contiguous layout segments,
and also to correct the ordering of layouts for those device drivers that
don't necessarily want to place the read-write layouts first.

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

NFSv4.1/pnfs: Add sanity check for the layout range returned by the server

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

NFSv4.2/pnfs: Make the layoutstats timer configurable

Allow advanced users to set the layoutstats timer in order to lengthen
or shorten the period between layoutstat transmissions to the server.

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

NFS41: remove NFS_LAYOUT_ROC flag

If we return delegation before closing, we fail to do roc check
during close because NFS_LAYOUT_ROC is cleared by delegreturn
and it causes layouts to be still hanging around after delegreturn
+ close, which is a voilation against protocol.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1/pnfs: Add a tracepoint for return-on-close events

Allow tracing of return-on-close.

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

pNFS: Fix an unused variable warning in pnfs_roc_get_barrier

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

NFS41: make sure sending LAYOUTRETURN before close if marked so

If layout is marked by NFS_LAYOUT_RETURN_BEFORE_CLOSE, we should always
send LAYOUTRETURN before close, and we don't need to do ROC drain if we
do send LAYOUTRETURN.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1/pnfs: Fix a close/delegreturn hang when return-on-close is set

The helper pnfs_roc() has already verified that we have no delegations,
and no further open files, hence no outstanding I/O and it has marked
all the return-on-close lsegs as being invalid.
Furthermore, it sets the NFS_LAYOUT_RETURN bit, thus serialising the
close/delegreturn with all future layoutget calls on this inode.

The checks in pnfs_roc_drain() for valid layout segments are therefore
redundant: those cannot exist until another layoutget completes.
The other check for whether or not NFS_LAYOUT_RETURN is set, actually
causes a hang, since we already know that we hold that flag.

To fix, we therefore strip out all the functionality in pnfs_roc_drain()
except the retrieval of the barrier state, and then rename the function
accordingly.

Reported-by: Christoph Hellwig <hch@infradead.org>
Fixes: 5c4a79fb2b1c ("Don't prevent layoutgets when doing return-on-close")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1/pnfs: Remove redundant wakeup in pnfs_send_layoutreturn()

pnfs_clear_layoutreturn_waitbit() should already be calling
rpc_wake_up(&NFS_SERVER(ino)->roc_rpcwaitq) for us.

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

NFSv4.1/pnfs: Remove redundant check in pnfs_layoutgets_blocked()

layoutget now should already be serialised w.r.t. layout returns

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

NFSv4.1/pnfs: Remove redundant lo->plh_block_lgets in layoutreturn

The NFS_LAYOUT_RETURN bit already suffices to ensure that layoutget
is blocked.

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

NFSv4.1/pnfs: Don't prevent layoutgets when doing return-on-close

If there is an outstanding return-on-close, then we just want new
layoutget requests to wait rather than fail.

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

NFSv4.1/pnfs: Fix serialisation of layout return and layoutget

We should always test for outstanding layout returns, whether or not
pnfs_should_retry_layoutget() is true.

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

NFSv4.1/pnfs: Remove redundant checks in pnfs_layoutgets_blocked()

If there are no valid layout segments, then we should already have
checked in pnfs_update_layout() whether or not this is the first
layoutget.

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

NFSv4.2/pnfs: Use GFP_NOIO for layoutstat reporting in the writeback path

Prevent a potential deadlock.

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

nfs: plug memory leak when ->prepare_layoutcommit fails

"data" is currently leaked when the prepare_layoutcommit operation
returns an error. Put the cred before taking the spinlock in that
case, take the lock and then goto out_unlock which will drop the
lock and then free "data".

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pNFS: Don't throw out valid layout segments

It is OK for layout segments to remain hashed even if no-one holds any
references to them, provided that the segments are still valid.

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

pNFS: pnfs_roc_drain() fix a race with open

If a process reopens the file before we can send off the CLOSE/DELEGRETURN,
then pnfs_roc_drain() may end up waiting for a new set of layout segments
that are marked as return-on-close, but haven't yet been returned.

Fix this by only waiting for those layout segments that were invalidated in
pnfs_roc().

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

pNFS: Fix races between return-on-close and layoutreturn.

If one or more of the layout segments reports an error during I/O, then
we may have to send a layoutreturn to report the error back to the NFS
metadata server.
This patch ensures that the return-on-close code can detect the
outstanding layoutreturn, and not preempt it.

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

pNFS: pnfs_roc_drain should return 'true' when sleeping

Also clean up the case where we don't find a return-on-close layout segment.

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

NFSv4.2: LAYOUTSTATS is optional to implement

Make it so, by checking the return value for NFS4ERR_MOTSUPP and
caching the information as a server capability.

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

nfs: provide pnfs_report_layoutstat when NFS42 is disabled

kbuild test robot reported:
fs/built-in.o: In function `pnfs_report_layoutstat':
>> (.text+0x151a1c): undefined reference to `nfs42_proc_layoutstats_generic'

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs42: serialize LAYOUTSTATS calls of the same file

There is no need to report concurrently.

Reviewed-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pnfs: add pnfs_report_layoutstat helper function

Reviewed-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFS: Ensure we set NFS_CONTEXT_RESEND_WRITES when requeuing writes

If a write attempt fails, and the write is queued up for resending to
the server, as opposed to being dropped, then we need to set the
appropriate flag so that nfs_file_fsync() does the right thing.

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

pNFS: Fix a memory leak when attempted pnfs fails

pnfs_do_write() expects the call to pnfs_write_through_mds() to free the
pgio header and to release the layout segment before exiting. The problem
is that nfs_pgio_data_destroy() doesn't actually do this; it only frees
the memory allocated by nfs_generic_pgio().

Ditto for pnfs_do_read()...

Fix in both cases is to add a call to hdr->release(hdr).

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

NFSv4.1/pnfs: Separate out metadata and data consistency for pNFS

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

This patch separates out the 2 cases, allowing the files/flexfiles layout
drivers to optimise away the data consistency calls to layoutcommit.

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

NFSv4.1/pnfs: Ensure we send layoutcommit before return-on-close

We must not send a close or delegreturn that would result in a
return-on-close of the layout without ensuring that we've also
sent the necessary layoutcommit.

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

NFSv4.1/pnfs: Refactor pnfs_set_layoutcommit()

pnfs_set_layoutcommit() and pnfs_commit_set_layoutcommit() are 100% identical
except for the function arguments. Refactor to eliminate the difference.

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

NFSv4.1/pnfs: Fix setting of layoutcommit last write byte

If the NFS_INO_LAYOUTCOMMIT flag was unset, then we _must_ ensure that
we also reset the last write byte (lwb) for that layout. The current
code depends on us clearing the lwb when we clear NFS_INO_LAYOUTCOMMIT,
which is not the case when we call pnfs_clear_layoutcommit().

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

NFSv4.1: don't export static symbol

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
type T;
identifier f;
@@

static T f (...) { ... }

@@
identifier r.f;
declarer name EXPORT_SYMBOL_GPL;
@@

-EXPORT_SYMBOL_GPL(f);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pnfs: delete an unintended goto

There was an extra goto here where it shouldn't be, because of a merge
error.

Fixes: e2c63e091e29 ('Merge branch 'flexfiles'')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1: Fix pnfs_put_lseg races

pnfs_layoutreturn_free_lseg_async() can also race with inode put in
the general case. We can now fix this, and also simplify the code.

Cc: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1: pnfs_send_layoutreturn should use GFP_NOFS

In we want to be able to call pnfs_send_layoutreturn() from within the
writeback path, we really want it to use GFP_NOFS in order to prevent
recursion.

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

pnfs: lookup new lseg at lseg boundary

Before mirroring support was added, the pageio descriptor's pg_lseg was
set to null when an RPC was sent. Because of this, pg_init was called
at lseg boundaries with pg_lseg = NULL, and it could be set to the new
lseg.

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>

nfs41: .init_read and .init_write can be called with valid pg_lseg

With pgio refactoring in v3.15, .init_read and .init_write can be
called with valid pgio->pg_lseg. file layout was fixed at that time
by commit c6194271f (pnfs: filelayout: support non page aligned
layouts). But the generic helper still needs to be fixed.

Cc: stable@vger.kernel.org # 3.15+
Signed-off-by: Peng Tao <tao.peng@primarydata.com>

pnfs/flexfiles: Add the FlexFile Layout Driver

The flexfile layout is a new layout that extends the
file layout. It is currently being drafted as a specification at
https://datatracker.ietf.org/doc/draft-ietf-nfsv4-layout-types/

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>
Signed-off-by: Tao Peng <bergwolf@primarydata.com>

nfs41: wait for LAYOUTRETURN before retrying LAYOUTGET

Also take care to stop waiting if someone clears retry bit.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>

nfs41: add NFS_LAYOUT_RETRY_LAYOUTGET to layout header flags

Use it to indicate that LD wants to retry layoutget. LD can set
it whenever it wants the common pnfs code to return and retry
pnfs path through a new layout.

The bit gets cleared when client does a new layoutget, when client
closes the file (ROC case), or when kernel needs to evict the inode
(non-ROC case).

Signed-off-by: Peng Tao <tao.peng@primarydata.com>

nfs/flexfiles: send layoutreturn before freeing lseg

Otherwise we'll lose error tracking information when
encoding layoutreturn.

pnfs_put_lseg may be called from rpc callbacks. So we should not
call pnfs_send_layoutreturn directly because it can deadlock in
the rpc layer.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>

nfs41: introduce NFS_LAYOUT_RETURN_BEFORE_CLOSE

When it is set, generic pnfs would try to send layoutreturn right
before last close/delegation_return regard less NFS_LAYOUT_ROC is
set or not. LD can then make sure layoutreturn is always sent
rather than being omitted.

The difference against NFS_LAYOUT_RETURN is that
NFS_LAYOUT_RETURN_BEFORE_CLOSE does not block usage of the layout so
LD can set it and expect generic layer to try pnfs path at the
same time.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>

nfs41: allow async version layoutreturn

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>

nfs41: add range to layoutreturn args

So that callers can specify which range to return.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>

pnfs: allow LD to ask to resend read through pnfs

If current IO cannot be completed due to some transient errors,
LD may want to ask generic layer to resend the request through
pnfs again.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>

nfs: add nfs_pgio_current_mirror helper

Let it return current nfs_pgio_mirror in use depending on pg_mirror_count.
For read, we always use pg_mirrors[0], so this effectively gives us freedom
to use pg_mirror_idx to track the actual mirror to read from through out the
IO stack.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>

nfs41: add a debug warning if we destroy an unempty layout

So that we can detect the case if some layout segments are still
pinned which is surely a bug that we need to fix.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>

nfs: add mirroring support to pgio layer

This patch adds mirrored write support to the pgio layer. The default
is to use one mirror, but pgio callers may define callbacks to change
this to any value up to the (arbitrarily selected) limit of 16.

The basic idea is to break out members of nfs_pageio_descriptor that cannot
be shared between mirrored DSes and put them in a new structure.

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>

pnfs: release lseg in pnfs_generic_pg_cleanup

This is needed to support mirrored writes - the first write can't just
trash the lseg, we need to keep it around until all mirrors have
written.

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>

nfs41: clear NFS_LAYOUT_RETURN if layoutreturn is sent or failed to send

So that pnfs path is not disabled for ever.

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

nfs41: send layoutreturn in last put_lseg

If current lseg is the last lseg marked with NFS_LSEG_LAYOUTRETURN,
send layoutreturn.

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

nfs41: don't use a layout if it is marked for returning

And if we are to return the same type of layouts, don't bother
sending more layoutgets.

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

nfs41: add a helper to mark layout for return

It marks all matching layout segments as NFS_LSEG_LAYOUTRETURN,
which is an indicator for pnfs_put_lseg() to send layoutreturn,
and also prevents pnfs_update_layout() from using the returning
segments. Once it is set, it never gets cleared.

It also sets proper io failure bit so that pnfs path can be retried
after PNFS_LAYOUTGET_RETRY_TIMEOUT second.

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

nfs41: make a helper function to send layoutreturn

It allows to specify different iomode to return.

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

nfs41: pass iomode through layoutreturn args

So that it is possible to return a specific iomode layouts.

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

nfs41: serialize first layoutget of a file

Per RFC 5661 Errata 3208:
| A client MAY always forget its layout state and associated
| layout stateid at any time (See also section 12.5.5.1).
| In such case, the client MUST use a non-layout stateid for the next
| LAYOUTGET operation. This will signal the server that the client has
| no more layouts on the file and its respective layout state can be
| released before issuing a new layout in response to LAYOUTGET.

In order to make such a signal unique to server, client needs to serialize
all layoutgets using non-layout stateid. We implement this by serializing
layoutgets when client has no layout segments at hand.

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

nfs41: close a small race window when adding new layout to global list

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

nfs/flexclient: export pnfs_layoutcommit_inode

flexfiles needs to start layoutcommit when necessary

Signed-off-by: Peng Tao <tao.peng@primarydata.com>

NFSv4.1: Optimise layout return-on-close

Optimise the layout return on close code by ensuring that

1) Add a check for whether we hold a layout before taking any spinlocks
2) Only take the spin lock once
3) Use nfs_state->state to speed up open file checks

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

NFSv4.1/pnfs: replace broken pnfs_put_lseg_async

You cannot call pnfs_put_lseg_async() more than once per lseg, so it
is really an inappropriate way to deal with a refcount issue.

Instead, replace it with a function that decrements the refcount, and
puts the final 'free' operation (which is incompatible with locks) on
the workqueue.

Cc: Weston Andros Adamson <dros@primarydata.com>
Fixes: e6cf82d1830f: pnfs: add pnfs_put_lseg_async
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pnfs: add return_range method

If a layout driver keeps per-inode state outside of the layout segments it
needs to be notified of any layout returns or recalls on an inode, and not
just about the freeing of layout segments. Add a method to acomplish this,
which will allow the block layout driver to handle the case of truncated
and re-expanded files properly.

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

pnfs: force a layout commit when encountering busy segments during recall

Expedite layout recall processing by forcing a layout commit when
we see busy segments. Without it the layout recall might have to wait
until the VM decided to start writeback for the file, which can introduce
long delays.

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

pnfs: allow splicing pre-encoded pages into the layoutcommit args

Currently there is no XDR buffer space allocated for the per-layout driver
layoutcommit payload, which leads to server buffer overflows in the
blocklayout driver even under simple workloads. As we can't do per-layout
sizes for XDR operations we'll have to splice a previously encoded list
of pages into the XDR stream, similar to how we handle ACL buffers.

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

pnfs: avoid using stale stateids after layoutreturn

After we issued a layoutreturn operations the may free the layout stateid
and will thus cause bad stateid error when the client uses it again.

We currently try to avoid this case by chosing the open stateid if not
lsegs are present for this inode. But various places can hold refererence
on lsegs and thus cause the list not to be empty shortly after a layout
return. Add an explicit flag to mark the current layout stateid invalid
and force usage of the openstateid after we did a full file layoutreturn.

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

pnfs: don't check sequence on new stateids in layoutget

When layoutget returns an entirely new layout stateid it should not
check the generation counter as the new stateid will start with a new
counter entirely unrelated to old one.

The current behavior causes constant layoutget failures against a block
server which allocates a new stateid after an recall that removed all
outstanding layouts.

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

pnfs: do not pass uninitialized lsegs to ->free_lseg

Ensure the lsegs are initialized early so that we don't pass an unitialized
one back to ->free_lseg during error processing.

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

nfs41: add a helper function to set layoutcommit after commit

Track lwb in nfs_commit_data so that we can use it to setup
layoutcommit in commit_done callback.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pnfs: add pnfs_put_lseg_async

This is useful when lsegs need to be released while holding locks.

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

sched: Remove proliferation of wait_on_bit() action functions

The current "wait_on_bit" interface requires an 'action'
function to be provided which does the actual waiting.
There are over 20 such functions, many of them identical.
Most cases can be satisfied by one of just two functions, one
which uses io_schedule() and one which just uses schedule().

So:
Rename wait_on_bit and wait_on_bit_lock to
wait_on_bit_action and wait_on_bit_lock_action
to make it explicit that they need an action function.

Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io
which are *not* given an action function but implicitly use
a standard one.
The decision to error-out if a signal is pending is now made
based on the 'mode' argument rather than being encoded in the action
function.

All instances of the old wait_on_bit and wait_on_bit_lock which
can use the new version have been changed accordingly and their
action functions have been discarded.
wait_on_bit{_lock} does not return any specific error code in the
event of a signal so the caller must check for non-zero and
interpolate their own error code as appropriate.

The wait_on_bit() call in __fscache_wait_on_invalidate() was
ambiguous as it specified TASK_UNINTERRUPTIBLE but used
fscache_wait_bit_interruptible as an action function.
David Howells confirms this should be uniformly
"uninterruptible"

The main remaining user of wait_on_bit{,_lock}_action is NFS
which needs to use a freezer-aware schedule() call.

A comment in fs/gfs2/glock.c notes that having multiple 'action'
functions is useful as they display differently in the 'wchan'
field of 'ps'. (and /proc/$PID/wchan).
As the new bit_wait{,_io} functions are tagged "__sched", they
will not show up at all, but something higher in the stack. So
the distinction will still be visible, only with different
function names (gds2_glock_wait versus gfs2_glock_dq_wait in the
gfs2/glock.c case).

Since first version of this patch (against 3.15) two new action
functions appeared, on in NFS and one in CIFS. CIFS also now
uses an action function that makes the same freezer aware
schedule call as NFS.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: David Howells <dhowells@redhat.com> (fscache, keys)
Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2)
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>

pnfs: clean up *_resend_to_mds

Clean up pnfs_read_done_resend_to_mds and pnfs_write_done_resend_to_mds:
- instead of passing all arguments from a nfs_pgio_header, just pass the header
- share the common code

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs: remove pgio_header refcount, related cleanup

The refcounting on nfs_pgio_header was related to there being (possibly)
more than one nfs_pgio_data. Now that nfs_pgio_data has been merged into
nfs_pgio_header, there is no reason to do this ref counting. Just call
the completion callback on nfs_pgio_release/nfs_pgio_error.

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

nfs: merge nfs_pgio_data into _header

struct nfs_pgio_data only exists as a member of nfs_pgio_header, but is
passed around everywhere, because there used to be multiple _data structs
per _header. Many of these functions then use the _data to find a pointer
to the _header. This patch cleans this up by merging the nfs_pgio_data
structure into nfs_pgio_header and passing nfs_pgio_header around instead.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs: move nfs_pgio_data and remove nfs_rw_header

nfs_rw_header was used to allocate an nfs_pgio_header along with an
nfs_pgio_data, because a _header would need at least one _data.

Now there is only ever one nfs_pgio_data for each nfs_pgio_header -- move
it to nfs_pgio_header and get rid of nfs_rw_header.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pnfs: fix lockup caused by pnfs_generic_pg_test

end_offset and req_offset both return u64 - avoid casting to u32
until it's needed, when it's less than the (u32) size returned by
nfs_generic_pg_test.

Also, fix the comments in pnfs_generic_pg_test.

Running the cthon04 special tests caused this lockup in the
"write/read at 2GB, 4GB edges" test when running against a file layout server:

BUG: soft lockup - CPU#0 stuck for 22s! [bigfile2:823]
Modules linked in: nfs_layout_nfsv41_files rpcsec_gss_krb5 nfsv4 nfs fscache ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_mangle ip6table_filter ip6_tables iptable_nat nf_nat_ipv4 nf_nat iptable_mangle ppdev crc32c_intel aesni_intel aes_x86_64 glue_helper lrw gf128mul ablk_helper cryptd serio_raw e1000 shpchp i2c_piix4 i2c_core parport_pc parport nfsd auth_rpcgss oid_registry exportfs nfs_acl lockd sunrpc btrfs xor zlib_deflate raid6_pq mptspi scsi_transport_spi mptscsih mptbase ata_generic floppy autofs4
irq event stamp: 205958
hardirqs last enabled at (205957): [<ffffffff814a62dc>] restore_args+0x0/0x30
hardirqs last disabled at (205958): [<ffffffff814ad96a>] apic_timer_interrupt+0x6a/0x80
softirqs last enabled at (205956): [<ffffffff8103ffb2>] __do_softirq+0x1ea/0x2ab
softirqs last disabled at (205951): [<ffffffff8104026d>] irq_exit+0x44/0x9a
CPU: 0 PID: 823 Comm: bigfile2 Not tainted 3.15.0-rc1-branch-pgio_plus+ #3
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
task: ffff8800792ec480 ti: ffff880078c4e000 task.ti: ffff880078c4e000
RIP: 0010:[<ffffffffa02ce51f>] [<ffffffffa02ce51f>] nfs_page_group_unlock+0x3e/0x4b [nfs]
RSP: 0018:ffff880078c4fab0 EFLAGS: 00000202
RAX: 0000000000000fff RBX: ffff88006bf83300 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff88006bf83300
RBP: ffff880078c4fab8 R08: 0000000000000001 R09: 0000000000000000
R10: ffffffff8249840c R11: 0000000000000000 R12: 0000000000000035
R13: ffff88007ffc72d8 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f45f11b7740(0000) GS:ffff88007f200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3a8cb632d0 CR3: 000000007931c000 CR4: 00000000001407f0
Stack:
ffff88006bf832c0 ffff880078c4fb00 ffffffffa02cec22 ffff880078c4fad8
00000fff810f9d99 ffff880078c4fca0 ffff88006bf832c0 ffff88006bf832c0
ffff880078c4fca0 ffff880078c4fd60 ffff880078c4fb28 ffffffffa02cee34
Call Trace:
[<ffffffffa02cec22>] __nfs_pageio_add_request+0x298/0x34f [nfs]
[<ffffffffa02cee34>] nfs_pageio_add_request+0x1f/0x42 [nfs]
[<ffffffffa02d1722>] nfs_do_writepage+0x1b5/0x1e4 [nfs]
[<ffffffffa02d1764>] nfs_writepages_callback+0x13/0x25 [nfs]
[<ffffffffa02d1751>] ? nfs_do_writepage+0x1e4/0x1e4 [nfs]
[<ffffffff810eb32d>] write_cache_pages+0x254/0x37f
[<ffffffffa02d1751>] ? nfs_do_writepage+0x1e4/0x1e4 [nfs]
[<ffffffff8149cf9e>] ? printk+0x54/0x56
[<ffffffff810eacca>] ? __set_page_dirty_nobuffers+0x22/0xe9
[<ffffffffa016d864>] ? put_rpccred+0x38/0x101 [sunrpc]
[<ffffffffa02d1ae1>] nfs_writepages+0xb4/0xf8 [nfs]
[<ffffffff810ec59c>] do_writepages+0x21/0x2f
[<ffffffff810e36e8>] __filemap_fdatawrite_range+0x55/0x57
[<ffffffff810e374a>] filemap_write_and_wait_range+0x2d/0x5b
[<ffffffffa030ba0a>] nfs4_file_fsync+0x3a/0x98 [nfsv4]
[<ffffffff8114ee3c>] vfs_fsync_range+0x18/0x20
[<ffffffff810e40c2>] generic_file_aio_write+0xa7/0xbd
[<ffffffffa02c5c6b>] nfs_file_write+0xf0/0x170 [nfs]
[<ffffffff81129215>] do_sync_write+0x59/0x78
[<ffffffff8112956c>] vfs_write+0xab/0x107
[<ffffffff81129c8b>] SyS_write+0x49/0x7f
[<ffffffff814acd12>] system_call_fastpath+0x16/0x1b

Reported-by: Anna Schumaker <Anna.Schumaker@netapp.com>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pnfs: allow non page aligned pnfs layout segments

Remove alignment checks that would revert to MDS and change pg_test
to return the max ammount left in the segment (or other pg_test call)
up to size of passed request, or 0 if no space is left.

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

nfs: remove data list from pgio header

Since the ability to split pages into subpage requests has been added,
nfs_pgio_header->rpc_list only ever has one pgio data.

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

nfs: chain calls to pg_test

Now that pg_test can change the size of the request (by returning a non-zero
size smaller than the request), pg_test functions that call other
pg_test functions must return the minimum of the result - or 0 if any fail.

Also clean up the logic of some pg_test functions so that all checks are
for contitions where coalescing is not possible.

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

nfs: modify pg_test interface to return size_t

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

For now, just return the size of the request if there is space, or 0
if there is not. This shouldn't change any behavior as it acts
the same as when the pg_test functions returned bool.

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

NFS: Create a generic_pgio function

These functions are almost identical on both the read and write side.
FLUSH_COND_STABLE will never be set for the read path, so leaving it in
the generic code won't hurt anything.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFS: Create a common rw_header_alloc and rw_header_free function

I create a new struct nfs_rw_ops to decide the differences between reads
and writes. This struct will be set when initializing a new
nfs_pgio_descriptor, and then passed on to the nfs_rw_header when a new
header is allocated.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFS: Create a common pgio_alloc and pgio_release function

These functions are identical for the read and write paths so they can
be combined.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFS: Create a common read and write header struct

The only difference is the write verifier field, but we can keep that
for a little bit longer.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFS: Create a common read and write data struct

At this point, the only difference between nfs_read_data and
nfs_write_data is the write verifier.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs: remove ->read_pageio_init from rpc ops

The read_pageio_init method is just a very convoluted way to grab the
right nfs_pageio_ops vector. The vector to chose is not a choice of
protocol version, but just a pNFS vs MDS I/O choice that can simply be
done inside nfs_pageio_init_read based on the presence of a layout
driver, and a new force_mds flag to the special case of falling back
to MDS I/O on a pNFS-capable volume.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs: remove ->write_pageio_init from rpc ops

The write_pageio_init method is just a very convoluted way to grab the
right nfs_pageio_ops vector. The vector to chose is not a choice of
protocol version, but just a pNFS vs MDS I/O choice that can simply be
done inside nfs_pageio_init_write based on the presence of a layout
driver, and a new force_mds flag to the special case of falling back
to MDS I/O on a pNFS-capable volume.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

arch: Mass conversion of smp_mb__*()

Mostly scripted conversion of the smp_mb__* barriers.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

NFSv4.1: Ensure that we free existing layout segments if we get a new layout

If the server returns a completely new layout stateid in response to our
LAYOUTGET, then make sure to free any existing layout segments.

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

NFSv4.1: Fix wraparound issues in pnfs_seqid_is_newer()

Subtraction of signed integers does not have well defined wraparound
semantics in the C99 standard. In order to be wraparound-safe, we
have to use unsigned subtraction, and then cast the result.

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

NFSv4.1: Fix a race in nfs4_write_inode

nfs4_write_inode() must not be allowed to exit until the layoutcommit
is done. That means that both NFS_INO_LAYOUTCOMMIT and
NFS_INO_LAYOUTCOMMITTING have to be cleared.

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

NFSv4: Add tracepoints for debugging reads and writes

Set up tracepoints to track read, write and commit, as well as
pNFS reads and writes and commits to the data server.

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

NFSv4.1: Clean up layout segment comparison helper names

Give them names that are a bit more consistent with the general
pNFS naming scheme.

- lo_seg_contained -> pnfs_lseg_range_contained
- lo_seg_intersecting -> pnfs_lseg_range_intersecting
- cmp_layout -> pnfs_lseg_range_cmp
- is_matching_lseg -> pnfs_lseg_range_match

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

NFSv4.1: layout segment comparison helpers should take 'const' parameters

Also strip off the unnecessary 'inline' declarations.

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

NFSv4.1: Simplify setting the layout header credential

ctx->cred == ctx->state->owner->so_cred, so let's just use the former.

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

NFSv4.1: Ensure that layoutreturn uses the correct credential

We need to use the same credential as was used for the layoutget
and/or layoutcommit operations.

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

NFSv4.1: Ensure that layoutget is called using the layout credential

Ensure that we use the same credential for layoutget, layoutcommit and
layoutreturn.

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

NFSv4: Fail I/O if the state recovery fails irrevocably

If state recovery fails with an ESTALE or a ENOENT, then we shouldn't
keep retrying. Instead, mark the stateid as being invalid and
fail the I/O with an EIO error.
For other operations such as POSIX and BSD file locking, truncate
etc, fail with an EBADF to indicate that this file descriptor is no
longer valid.

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

NFSv4.1: Add a helper pnfs_commit_and_return_layout

In order to be able to safely return the layout in nfs4_proc_setattr,
we need to block new uses of the layout, wait for all outstanding
users of the layout to complete, commit the layout and then return it.

This patch adds a helper in order to do all this safely.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>

NFSv4.1: Always clear the NFS_INO_LAYOUTCOMMIT in layoutreturn

Note that clearing NFS_INO_LAYOUTCOMMIT is tricky, since it requires
you to also clear the NFS_LSEG_LAYOUTCOMMIT bits from the layout
segments.
The only two sites that need to do this are the ones that call
pnfs_return_layout() without first doing a layout commit.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Benny Halevy <bhalevy@tonian.com>
Cc: stable@vger.kernel.org

NFSv4.1: Fix a race in pNFS layoutcommit

We need to clear the NFS_LSEG_LAYOUTCOMMIT bits atomically with the
NFS_INO_LAYOUTCOMMIT bit, otherwise we may end up with situations
where the two are out of sync.
The first half of the problem is to ensure that pnfs_layoutcommit_inode
clears the NFS_LSEG_LAYOUTCOMMIT bit through pnfs_list_write_lseg.
We still need to keep the reference to those segments until the RPC call
is finished, so in order to make it clear _where_ those references come
from, we add a helper pnfs_list_write_lseg_done() that cleans up after
pnfs_list_write_lseg.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Benny Halevy <bhalevy@tonian.com>
Cc: stable@vger.kernel.org

NFSv4.1: LAYOUTGET EDELAY loops timeout to the MDS

The client will currently try LAYOUTGETs forever if a server is returning
NFS4ERR_LAYOUTTRYLATER or NFS4ERR_RECALLCONFLICT - even if the client no
longer needs the layout (ie process killed, unmounted).

This patch uses the DS timeout value (module parameter 'dataserver_timeo'
via rpc layer) to set an upper limit of how long the client tries LATOUTGETs
in this situation. Once the timeout is reached, IO is redirected to the MDS.

This also changes how the client checks if a layout is on the clp list
to avoid a double list_add.

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

pnfs: fix resend_to_mds for directio

Pass the directio request on pageio_init to clean up the API.

Percolate pg_dreq from original nfs_pageio_descriptor to the
pnfs_{read,write}_done_resend_to_mds and use it on respective
call to nfs_pageio_init_{read,write} on the newly created
nfs_pageio_descriptor.

Reproduced by command:
mount -o vers=4.1 server:/ /mnt
dd bs=128k count=8 if=/dev/zero of=/mnt/dd.out oflag=direct

BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
IP: [<ffffffffa021a3a8>] atomic_inc+0x4/0x9 [nfs]
PGD 34786067 PUD 34794067 PMD 0
Oops: 0002 [#1] SMP
Modules linked in: nfs_layout_nfsv41_files nfsv4 nfs nfsd lockd nfs_acl auth_rpcgss exportfs sunrpc btrfs zlib_deflate libcrc32c ipv6 autofs4
CPU 1
Pid: 259, comm: kworker/1:2 Not tainted 3.8.0-rc6 #2 Bochs Bochs
RIP: 0010:[<ffffffffa021a3a8>] [<ffffffffa021a3a8>] atomic_inc+0x4/0x9 [nfs]
RSP: 0018:ffff880038f8fa68 EFLAGS: 00010206
RAX: ffffffffa021a6a9 RBX: ffff880038f8fb48 RCX: 00000000000a0000
RDX: ffffffffa021e616 RSI: ffff8800385e9a40 RDI: 0000000000000028
RBP: ffff880038f8fa68 R08: ffffffff81ad6720 R09: ffff8800385e9510
R10: ffffffffa0228450 R11: ffff880038e87418 R12: ffff8800385e9a40
R13: ffff8800385e9a70 R14: ffff880038f8fb38 R15: ffffffffa0148878
FS: 0000000000000000(0000) GS:ffff88003e400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000028 CR3: 0000000034789000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process kworker/1:2 (pid: 259, threadinfo ffff880038f8e000, task ffff880038302480)
Stack:
ffff880038f8fa78 ffffffffa021a6bf ffff880038f8fa88 ffffffffa021bb82
ffff880038f8fae8 ffffffffa021f454 ffff880038f8fae8 ffffffff8109689d
ffff880038f8fab8 ffffffff00000006 0000000000000000 ffff880038f8fb48
Call Trace:
[<ffffffffa021a6bf>] nfs_direct_pgio_init+0x16/0x18 [nfs]
[<ffffffffa021bb82>] nfs_pgheader_init+0x6a/0x6c [nfs]
[<ffffffffa021f454>] nfs_generic_pg_writepages+0x51/0xf8 [nfs]
[<ffffffff8109689d>] ? mark_held_locks+0x71/0x99
[<ffffffffa0148878>] ? rpc_release_resources_task+0x37/0x37 [sunrpc]
[<ffffffffa021bc25>] nfs_pageio_doio+0x1a/0x43 [nfs]
[<ffffffffa021be7c>] nfs_pageio_complete+0x16/0x2c [nfs]
[<ffffffffa02608be>] pnfs_write_done_resend_to_mds+0x95/0xc5 [nfsv4]
[<ffffffffa0148878>] ? rpc_release_resources_task+0x37/0x37 [sunrpc]
[<ffffffffa028e27f>] filelayout_reset_write+0x8c/0x99 [nfs_layout_nfsv41_files]
[<ffffffffa028e5f9>] filelayout_write_done_cb+0x4d/0xc1 [nfs_layout_nfsv41_files]
[<ffffffffa024587a>] nfs4_write_done+0x36/0x49 [nfsv4]
[<ffffffffa021f996>] nfs_writeback_done+0x53/0x1cc [nfs]
[<ffffffffa021fb1d>] nfs_writeback_done_common+0xe/0x10 [nfs]
[<ffffffffa028e03d>] filelayout_write_call_done+0x28/0x2a [nfs_layout_nfsv41_files]
[<ffffffffa01488a1>] rpc_exit_task+0x29/0x87 [sunrpc]
[<ffffffffa014a0c9>] __rpc_execute+0x11d/0x3cc [sunrpc]
[<ffffffff810969dc>] ? trace_hardirqs_on_caller+0x117/0x173
[<ffffffffa014a39f>] rpc_async_schedule+0x27/0x32 [sunrpc]
[<ffffffffa014a378>] ? __rpc_execute+0x3cc/0x3cc [sunrpc]
[<ffffffff8105f8c1>] process_one_work+0x226/0x422
[<ffffffff8105f7f4>] ? process_one_work+0x159/0x422
[<ffffffff81094757>] ? lock_acquired+0x210/0x249
[<ffffffffa014a378>] ? __rpc_execute+0x3cc/0x3cc [sunrpc]
[<ffffffff810600d8>] worker_thread+0x126/0x1c4
[<ffffffff8105ffb2>] ? manage_workers+0x240/0x240
[<ffffffff81064ef8>] kthread+0xb1/0xb9
[<ffffffff81064e47>] ? __kthread_parkme+0x65/0x65
[<ffffffff815206ec>] ret_from_fork+0x7c/0xb0
[<ffffffff81064e47>] ? __kthread_parkme+0x65/0x65
Code: 00 83 38 02 74 12 48 81 4b 50 00 00 01 00 c7 83 60 07 00 00 01 00 00 00 48 89 df e8 55 fe ff ff 5b 41 5c 5d c3 66 90 55 48 89 e5 <f0> ff 07 5d c3 55 48 89 e5 f0 ff 0f 0f 94 c0 84 c0 0f 95 c0 0f
RIP [<ffffffffa021a3a8>] atomic_inc+0x4/0x9 [nfs]
RSP <ffff880038f8fa68>
CR2: 0000000000000028

Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Cc: stable@kernel.org [>= 3.6]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4.1: Fix bulk recall and destroy of layouts

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

pnfs: Increase the refcount when LAYOUTGET fails the first time

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: Yanchuan Nian <ycnian@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 3.7]

NFSv4.1: Remove assertion BUG_ON()s from the files and generic layout code

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

NFSv4.1: Remove unused function last_byte_offset

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

nfs: Check whether a layout pointer is NULL before free it

The new layout pointer in pnfs_find_alloc_layout() may be NULL because of
out of memory. we must do some check work, otherwise pnfs_free_layout_hdr()
will go wrong because it can not deal with a NULL pointer.

Signed-off-by: Yanchuan Nian <ycnian@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS41: send real read size in layoutget

For buffer read, use offst-to-isize.

For direct read, use dreq->bytes_left.

Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS41: send real write size in layoutget

For buffer write, block layout client scan inode mapping to find
next hole and use offset-to-hole as layoutget length. Object
layout client uses offset-to-isize as layoutget length.

For direct write, both block layout and object layout use dreq->bytes_left.

Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4.1: Cleanup ugliness in pnfs_layoutgets_blocked()

Split it into two functions, one which checks if layoutgets are blocked,
and one which checks if the layout stateid has expired.

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

NFSv4.1: Ensure that the layout sequence id stays 'close' to the current

Clamp the layout barrier sequence id to the current sequence id
minus the maximum number of outstanding layoutget requests.

Also ensure that we correctly initialise lo->plh_barrier if there are
no layout segments associated to this layout header.

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

NFSv4.1: Deal with seqid wraparound in the pNFS return-on-close code

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

NFSv4.1: Deal with wraparound when updating the layout "barrier" seqid

...and fix a bug in pnfs_set_layout_stateid.

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

NFSv4.1: Deal with wraparound issues when updating the layout stateid

...and add a helper function.

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

NFSv4.1: Always set the layout stateid if this is the first layoutget

If the list of layout segments is empty, we must unconditionally set
the layout stateid.

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

NFSv4.1: Fix another refcount issue in pnfs_find_alloc_layout

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

NFSv4.1: _pnfs_return_layout() shouldn't invalidate the layout on failure

Failure of the layoutreturn allocation fails is not a good reason to
mark the pnfs_layout_hdr as having failed a layoutget or i/o. Just
exit cleanly.

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

NFSv4.1: Remove the NFS_LAYOUT_RETURNED state

It serves no purpose that the test for whether or not we have valid
layout segments doesn't already serve.

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

NFSv4.1: Clear NFS_LAYOUT_BULK_RECALL when the layout segments are freed

Once all the affected layout segments have been freed up, clear the
NFS_LAYOUT_BULK_RECALL flag so that we can reuse the pnfs_layout_hdr

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

NFSv4.1: Get rid of the NFS_LAYOUT_DESTROYED state

We already have a mechanism for blocking LAYOUTGET by means of the
plh_block_lgets counter. The only "service" that NFS_LAYOUT_DESTROYED
provides at this point is to block layoutget once the layout segment
list is empty, which basically means that you have to wait until
the pnfs_layout_hdr is destroyed before you can do pNFS on that file
again.

This patch enables the reuse of the pnfs_layout_hdr if the layout
segment list is empty.

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

NFSv4.1: Remove unused 'default allocation' for pnfs_alloc_layout_hdr()

...and ditto for pnfs_free_layout_hdr()

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

NFSv4.1: Get rid of pNFS spin lock debugging asserts...

These are all in static declared functions that are called only once.

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

NFSv4.1: Balance pnfs_layout_hdr refcount in pnfs_layout_(insert|remove)_lseg

Ensure that the reference count for pnfs_layout_hdr reverts to the
original value after a call to pnfs_layout_remove_lseg().

Note that the caller is expected to hold a reference to the struct
pnfs_layout_hdr.

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