If we have to retransmit requests, try to join their page groups
first.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Refactor nfs_lock_and_join_requests() in order to separate out the
subrequest merging into its own function nfs_lock_and_join_group()
that can be used by O_DIRECT.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If we have to split the request up into subrequests, we have to submit
the request pointed to by the function call parameter last, in case
there is an error or other issue that causes us to exit before the
last request is submitted. The reason is that the caller is expected
to perform cleanup in those cases.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Clean up nfs_lock_and_join_requests() to simplify the calculation
of the range covered by the page group, taking into account the
presence of mirrors.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We need to trust that desc->pg_mirror_idx is set correctly, whether
or not mirroring is enabled.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

If we just set the mirror count to 1 without first clearing out
the mirrors, we can leak queued up requests.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

nfs_direct_write_scan_commit_list() will lock the request and bump
the reference count, but we also need to account for the reference
that was taken when we initially added the request to the commit list.

Fixes: fb5f7f20 ("NFS: commit errors should be fatal")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We need to ensure that we create the mirror requests before calling
nfs_pageio_add_request_mirror() on the request we are adding.
Otherwise, we can end up with a use-after-free if the call to
nfs_pageio_add_request_mirror() triggers I/O.

Fixes: c917cfaf ("NFS: Fix up NFS I/O subrequest creation")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

When a subrequest is being detached from the subgroup, we want to
ensure that it is not holding the group lock, or in the process
of waiting for the group lock.

Fixes: 5b2b5187 ("NFS: Fix nfs_page_group_destroy() and nfs_lock_and_join_requests() race cases")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

When we detach a subrequest from the list, we must also release the
reference it holds to the parent.

Fixes: 5b2b5187 ("NFS: Fix nfs_page_group_destroy() and nfs_lock_and_join_requests() race cases")
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

NFSoRDMA Client Updates for Linux 5.7

New Features:
- Allow one active connection and several zombie connections to prevent
  blocking if the remote server is unresponsive.

Bugfixes and Cleanups:
- Enhance MR-related trace points
- Refactor connection set-up and disconnect functions
- Make Protection Domains per-connection instead of per-transport
- Merge struct rpcrdma_ia into rpcrdma_ep

If the FLUSH_SYNC flag is set, nfs_initiate_pgio() will currently
wait for completion, and then return the status of the I/O operation.
What we actually want to report in nfs_pageio_doio() is whether or
not the RPC call was launched successfully, whereas actual I/O
status is intended handled in the reply callbacks.

Since FLUSH_SYNC is never set by any of the callers anyway, let's
just remove that code altogether.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Move from requesting only full file layout segments, to requesting
layout segments that match our I/O size. This means the server is
still free to return a full file layout, but we will no longer
error out if it does not.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Remove the requirement that the server always sends whole file
layouts.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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>

Check that the number of mirrors, and the mirror information matches
before deciding to merge layout segments in pNFS/flexfiles.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Fix up pnfs_layout_mark_request_commit() to alway reschedule the write
if the layout segment is invalid. Also minor cleanup.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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

Move the pNFS commit related operations into a separate structure
that can be carried by the pnfs_ds_commit_info.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Remove the unused bucket array in struct pnfs_ds_commit_info.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Lift filelayout_search_commit_reqs() into the generic pnfs/nfs code,
and add support for commit arrays.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Enable adding and lookup of per-layout segment commits in filelayout
and flexfilelayout.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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>

Add support for scanning the full list of per-layout segment commit
arrays to nfs_clear_pnfs_ds_commit_verifiers().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Instead of trying to save the commit verifiers and checking them against
previous writes, adopt the same strategy as for buffered writes, of
just checking the verifiers at commit time.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Fix the O_DIRECT code to avoid retries if the COMMIT fails with a fatal
error.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Add a pNFS callback to allow the O_DIRECT code to release the DS
commitinfo when freeing the dreq.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Add support for scanning the full list of per-layout segment commit
arrays to pnfs_generic_commit_pagelist().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Add support for scanning the full list of per-layout segment commit
arrays to pnfs_generic_recover_commit_reqs().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Add support for scanning the full list of per-layout segment commit
arrays to pnfs_generic_scan_commit_lists()
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

When we have multiple layout segments with different lists of mirrored
data, we need to track the commits on a per layout segment basis.
This patch adds a list to support this tracking in struct
pnfs_ds_commit_info.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Change the rpcrdma_xprt_disconnect() function so that it no longer
waits for the DISCONNECTED event.  This prevents blocking if the
remote is unresponsive.

In rpcrdma_xprt_disconnect(), the transport's rpcrdma_ep is
detached. Upon return from rpcrdma_xprt_disconnect(), the transport
(r_xprt) is ready immediately for a new connection.

The RDMA_CM_DEVICE_REMOVAL and RDMA_CM_DISCONNECTED events are now
handled almost identically.

However, because the lifetimes of rpcrdma_xprt structures and
rpcrdma_ep structures are now independent, creating an rpcrdma_ep
needs to take a module ref count. The ep now owns most of the
hardware resources for a transport.

Also, a kref is needed to ensure that rpcrdma_ep sticks around
long enough for the cm_event_handler to finish.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

rpcrdma_cm_event_handler() is always passed an @id pointer that is
valid. However, in a subsequent patch, we won't be able to extract
an r_xprt in every case. So instead of using the r_xprt's
presentation address strings, extract them from struct rdma_cm_id.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

I eventually want to allocate rpcrdma_ep separately from struct
rpcrdma_xprt so that on occasion there can be more than one ep per
xprt.

The new struct rpcrdma_ep will contain all the fields currently in
rpcrdma_ia and in rpcrdma_ep. This is all the device and CM settings
for the connection, in addition to per-connection settings
negotiated with the remote.

Take this opportunity to rename the existing ep fields from rep_* to
re_* to disambiguate these from struct rpcrdma_rep.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Completion errors after a disconnect often occur much sooner than a
CM_DISCONNECT event. Use this to try to detect connection loss more
quickly.

Note that other kernel ULPs do take care to disconnect explicitly
when a WR is flushed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up:
The upper layer serializes calls to xprt_rdma_close, so there is no
need for an atomic bit operation, saving 8 bytes in rpcrdma_ia.

This enables merging rpcrdma_ia_remove directly into the disconnect
logic.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Move rdma_cm_id creation into rpcrdma_ep_create() so that it is now
responsible for allocating all per-connection hardware resources.

With this clean-up, all three arms of the switch statement in
rpcrdma_ep_connect are exactly the same now, thus the switch can be
removed.

Because device removal behaves a little differently than
disconnection, there is a little more work to be done before
rpcrdma_ep_destroy() can release the connection's rdma_cm_id. So
it is not quite symmetrical with rpcrdma_ep_create() yet.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Make a Protection Domain (PD) a per-connection resource rather than
a per-transport resource. In other words, when the connection
terminates, the PD is destroyed.

Thus there is one less HW resource that remains allocated to a
transport after a connection is closed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: Simplify the synopses of functions in the connect and
disconnect paths in preparation for combining the rpcrdma_ia and
struct rpcrdma_ep structures.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: Simplify the synopses of functions in the post_send path
by combining the struct rpcrdma_ia and struct rpcrdma_ep arguments.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>