Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 757 insertions, 0 deletions

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
new file mode 100644
index 000000000..3fb10c8e4
--- /dev/null
+++ b/fs/nfs/callback_proc.c
@@ -0,0 +1,757 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/nfs/callback_proc.c
+ *
+ * Copyright (C) 2004 Trond Myklebust
+ *
+ * NFSv4 callback procedures
+ */
+
+#include <linux/errno.h>
+#include <linux/math.h>
+#include <linux/nfs4.h>
+#include <linux/nfs_fs.h>
+#include <linux/slab.h>
+#include <linux/rcupdate.h>
+#include <linux/types.h>
+
+#include "nfs4_fs.h"
+#include "callback.h"
+#include "delegation.h"
+#include "internal.h"
+#include "pnfs.h"
+#include "nfs4session.h"
+#include "nfs4trace.h"
+
+#define NFSDBG_FACILITY NFSDBG_CALLBACK
+
+__be32 nfs4_callback_getattr(void *argp, void *resp,
+			     struct cb_process_state *cps)
+{
+	struct cb_getattrargs *args = argp;
+	struct cb_getattrres *res = resp;
+	struct nfs_delegation *delegation;
+	struct inode *inode;
+
+	res->status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
+	if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
+		goto out;
+
+	memset(res->bitmap, 0, sizeof(res->bitmap));
+	res->status = htonl(NFS4ERR_BADHANDLE);
+
+	dprintk_rcu("NFS: GETATTR callback request from %s\n",
+		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
+
+	inode = nfs_delegation_find_inode(cps->clp, &args->fh);
+	if (IS_ERR(inode)) {
+		if (inode == ERR_PTR(-EAGAIN))
+			res->status = htonl(NFS4ERR_DELAY);
+		trace_nfs4_cb_getattr(cps->clp, &args->fh, NULL,
+				-ntohl(res->status));
+		goto out;
+	}
+
+	delegation = nfs4_get_valid_delegation(inode);
+	if (!delegation)
+		goto out_iput;
+	if ((delegation->type & FMODE_WRITE) == 0) {
+		nfs_put_delegation(delegation);
+		goto out_iput;
+	}
+	res->change_attr = delegation->change_attr;
+	nfs_put_delegation(delegation);
+
+	res->size = i_size_read(inode);
+	if (nfs_have_writebacks(inode))
+		res->change_attr++;
+	res->atime = inode_get_atime(inode);
+	res->ctime = inode_get_ctime(inode);
+	res->mtime = inode_get_mtime(inode);
+	res->bitmap[0] = (FATTR4_WORD0_CHANGE | FATTR4_WORD0_SIZE) &
+			 args->bitmap[0];
+	res->bitmap[1] = (FATTR4_WORD1_TIME_ACCESS |
+			  FATTR4_WORD1_TIME_METADATA |
+			  FATTR4_WORD1_TIME_MODIFY) & args->bitmap[1];
+	res->bitmap[2] = (FATTR4_WORD2_TIME_DELEG_ACCESS |
+			  FATTR4_WORD2_TIME_DELEG_MODIFY) & args->bitmap[2];
+	res->status = 0;
+out_iput:
+	trace_nfs4_cb_getattr(cps->clp, &args->fh, inode, -ntohl(res->status));
+	nfs_iput_and_deactive(inode);
+out:
+	dprintk("%s: exit with status = %d\n", __func__, ntohl(res->status));
+	return res->status;
+}
+
+__be32 nfs4_callback_recall(void *argp, void *resp,
+			    struct cb_process_state *cps)
+{
+	struct cb_recallargs *args = argp;
+	struct inode *inode;
+	__be32 res;
+	
+	res = htonl(NFS4ERR_OP_NOT_IN_SESSION);
+	if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
+		goto out;
+
+	dprintk_rcu("NFS: RECALL callback request from %s\n",
+		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
+
+	res = htonl(NFS4ERR_BADHANDLE);
+	inode = nfs_delegation_find_inode(cps->clp, &args->fh);
+	if (IS_ERR(inode)) {
+		if (inode == ERR_PTR(-EAGAIN))
+			res = htonl(NFS4ERR_DELAY);
+		trace_nfs4_cb_recall(cps->clp, &args->fh, NULL,
+				&args->stateid, -ntohl(res));
+		goto out;
+	}
+	/* Set up a helper thread to actually return the delegation */
+	switch (nfs_async_inode_return_delegation(inode, &args->stateid)) {
+	case 0:
+		res = 0;
+		break;
+	case -ENOENT:
+		res = htonl(NFS4ERR_BAD_STATEID);
+		break;
+	default:
+		res = htonl(NFS4ERR_RESOURCE);
+	}
+	trace_nfs4_cb_recall(cps->clp, &args->fh, inode,
+			&args->stateid, -ntohl(res));
+	nfs_iput_and_deactive(inode);
+out:
+	dprintk("%s: exit with status = %d\n", __func__, ntohl(res));
+	return res;
+}
+
+/*
+ * Lookup a layout inode by stateid
+ *
+ * Note: returns a refcount on the inode and superblock
+ */
+static struct inode *nfs_layout_find_inode_by_stateid(struct nfs_client *clp,
+		const nfs4_stateid *stateid)
+	__must_hold(RCU)
+{
+	struct nfs_server *server;
+	struct inode *inode;
+	struct pnfs_layout_hdr *lo;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
+		list_for_each_entry_rcu(lo, &server->layouts, plh_layouts) {
+			if (!pnfs_layout_is_valid(lo))
+				continue;
+			if (!nfs4_stateid_match_other(stateid, &lo->plh_stateid))
+				continue;
+			if (nfs_sb_active(server->super))
+				inode = igrab(lo->plh_inode);
+			else
+				inode = ERR_PTR(-EAGAIN);
+			rcu_read_unlock();
+			if (inode)
+				return inode;
+			nfs_sb_deactive(server->super);
+			return ERR_PTR(-EAGAIN);
+		}
+	}
+	rcu_read_unlock();
+	return ERR_PTR(-ENOENT);
+}
+
+/*
+ * Lookup a layout inode by filehandle.
+ *
+ * Note: returns a refcount on the inode and superblock
+ *
+ */
+static struct inode *nfs_layout_find_inode_by_fh(struct nfs_client *clp,
+		const struct nfs_fh *fh)
+{
+	struct nfs_server *server;
+	struct nfs_inode *nfsi;
+	struct inode *inode;
+	struct pnfs_layout_hdr *lo;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
+		list_for_each_entry_rcu(lo, &server->layouts, plh_layouts) {
+			nfsi = NFS_I(lo->plh_inode);
+			if (nfs_compare_fh(fh, &nfsi->fh))
+				continue;
+			if (nfsi->layout != lo)
+				continue;
+			if (nfs_sb_active(server->super))
+				inode = igrab(lo->plh_inode);
+			else
+				inode = ERR_PTR(-EAGAIN);
+			rcu_read_unlock();
+			if (inode)
+				return inode;
+			nfs_sb_deactive(server->super);
+			return ERR_PTR(-EAGAIN);
+		}
+	}
+	rcu_read_unlock();
+	return ERR_PTR(-ENOENT);
+}
+
+static struct inode *nfs_layout_find_inode(struct nfs_client *clp,
+		const struct nfs_fh *fh,
+		const nfs4_stateid *stateid)
+{
+	struct inode *inode;
+
+	inode = nfs_layout_find_inode_by_stateid(clp, stateid);
+	if (inode == ERR_PTR(-ENOENT))
+		inode = nfs_layout_find_inode_by_fh(clp, fh);
+	return inode;
+}
+
+/*
+ * Enforce RFC5661 section 12.5.5.2.1. (Layout Recall and Return Sequencing)
+ */
+static u32 pnfs_check_callback_stateid(struct pnfs_layout_hdr *lo,
+					const nfs4_stateid *new,
+					struct cb_process_state *cps)
+{
+	u32 oldseq, newseq;
+
+	/* Is the stateid not initialised? */
+	if (!pnfs_layout_is_valid(lo))
+		return NFS4ERR_NOMATCHING_LAYOUT;
+
+	/* Mismatched stateid? */
+	if (!nfs4_stateid_match_other(&lo->plh_stateid, new))
+		return NFS4ERR_BAD_STATEID;
+
+	newseq = be32_to_cpu(new->seqid);
+	/* Are we already in a layout recall situation? */
+	if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags))
+		return NFS4ERR_DELAY;
+
+	/*
+	 * Check that the stateid matches what we think it should be.
+	 * Note that if the server sent us a list of referring calls,
+	 * and we know that those have completed, then we trust the
+	 * stateid argument is correct.
+	 */
+	oldseq = be32_to_cpu(lo->plh_stateid.seqid);
+	if (newseq > oldseq + 1 && !cps->referring_calls)
+		return NFS4ERR_DELAY;
+
+	/* Crazy server! */
+	if (newseq <= oldseq)
+		return NFS4ERR_OLD_STATEID;
+
+	return NFS_OK;
+}
+
+static u32 initiate_file_draining(struct nfs_client *clp,
+				  struct cb_layoutrecallargs *args,
+				  struct cb_process_state *cps)
+{
+	struct inode *ino;
+	struct pnfs_layout_hdr *lo;
+	u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
+	LIST_HEAD(free_me_list);
+	bool return_range = false;
+
+	ino = nfs_layout_find_inode(clp, &args->cbl_fh, &args->cbl_stateid);
+	if (IS_ERR(ino)) {
+		if (ino == ERR_PTR(-EAGAIN))
+			rv = NFS4ERR_DELAY;
+		goto out_noput;
+	}
+
+	pnfs_layoutcommit_inode(ino, false);
+
+
+	spin_lock(&ino->i_lock);
+	lo = NFS_I(ino)->layout;
+	if (!lo) {
+		spin_unlock(&ino->i_lock);
+		goto out;
+	}
+	pnfs_get_layout_hdr(lo);
+	rv = pnfs_check_callback_stateid(lo, &args->cbl_stateid, cps);
+	if (rv != NFS_OK)
+		goto unlock;
+
+	/*
+	 * Enforce RFC5661 Section 12.5.5.2.1.5 (Bulk Recall and Return)
+	 */
+	if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
+		rv = NFS4ERR_DELAY;
+		goto unlock;
+	}
+
+	pnfs_set_layout_stateid(lo, &args->cbl_stateid, NULL, true);
+	switch (pnfs_mark_matching_lsegs_return(lo, &free_me_list,
+				&args->cbl_range,
+				be32_to_cpu(args->cbl_stateid.seqid),
+				args->cbl_layoutchanged)) {
+	case 0:
+	case -EBUSY:
+		/* There are layout segments that need to be returned */
+		rv = NFS4_OK;
+		break;
+	case -ENOENT:
+		set_bit(NFS_LAYOUT_DRAIN, &lo->plh_flags);
+		/* Embrace your forgetfulness! */
+		rv = NFS4ERR_NOMATCHING_LAYOUT;
+
+		return_range = true;
+	}
+unlock:
+	spin_unlock(&ino->i_lock);
+	if (return_range && NFS_SERVER(ino)->pnfs_curr_ld->return_range)
+		NFS_SERVER(ino)->pnfs_curr_ld->return_range(lo,
+			&args->cbl_range);
+	pnfs_free_lseg_list(&free_me_list);
+	/* Free all lsegs that are attached to commit buckets */
+	nfs_commit_inode(ino, 0);
+	pnfs_put_layout_hdr(lo);
+out:
+	nfs_iput_and_deactive(ino);
+out_noput:
+	trace_nfs4_cb_layoutrecall_file(clp, &args->cbl_fh, ino,
+			&args->cbl_stateid, args->cbl_layoutchanged, -rv);
+	return rv;
+}
+
+static u32 initiate_bulk_draining(struct nfs_client *clp,
+				  struct cb_layoutrecallargs *args)
+{
+	int stat;
+
+	if (args->cbl_recall_type == RETURN_FSID)
+		stat = pnfs_layout_destroy_byfsid(clp, &args->cbl_fsid,
+						  PNFS_LAYOUT_BULK_RETURN);
+	else
+		stat = pnfs_layout_destroy_byclid(clp, PNFS_LAYOUT_BULK_RETURN);
+	if (stat != 0)
+		return NFS4ERR_DELAY;
+	return NFS4ERR_NOMATCHING_LAYOUT;
+}
+
+static u32 do_callback_layoutrecall(struct nfs_client *clp,
+				    struct cb_layoutrecallargs *args,
+				    struct cb_process_state *cps)
+{
+	if (args->cbl_recall_type == RETURN_FILE)
+		return initiate_file_draining(clp, args, cps);
+	return initiate_bulk_draining(clp, args);
+}
+
+__be32 nfs4_callback_layoutrecall(void *argp, void *resp,
+				  struct cb_process_state *cps)
+{
+	struct cb_layoutrecallargs *args = argp;
+	u32 res = NFS4ERR_OP_NOT_IN_SESSION;
+
+	if (cps->clp)
+		res = do_callback_layoutrecall(cps->clp, args, cps);
+	return cpu_to_be32(res);
+}
+
+static void pnfs_recall_all_layouts(struct nfs_client *clp,
+				    struct cb_process_state *cps)
+{
+	struct cb_layoutrecallargs args;
+
+	/* Pretend we got a CB_LAYOUTRECALL(ALL) */
+	memset(&args, 0, sizeof(args));
+	args.cbl_recall_type = RETURN_ALL;
+	/* FIXME we ignore errors, what should we do? */
+	do_callback_layoutrecall(clp, &args, cps);
+}
+
+__be32 nfs4_callback_devicenotify(void *argp, void *resp,
+				  struct cb_process_state *cps)
+{
+	struct cb_devicenotifyargs *args = argp;
+	const struct pnfs_layoutdriver_type *ld = NULL;
+	uint32_t i;
+	__be32 res = 0;
+
+	if (!cps->clp) {
+		res = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
+		goto out;
+	}
+
+	for (i = 0; i < args->ndevs; i++) {
+		struct cb_devicenotifyitem *dev = &args->devs[i];
+
+		if (!ld || ld->id != dev->cbd_layout_type) {
+			pnfs_put_layoutdriver(ld);
+			ld = pnfs_find_layoutdriver(dev->cbd_layout_type);
+			if (!ld)
+				continue;
+		}
+		nfs4_delete_deviceid(ld, cps->clp, &dev->cbd_dev_id);
+	}
+	pnfs_put_layoutdriver(ld);
+out:
+	kfree(args->devs);
+	return res;
+}
+
+/*
+ * Validate the sequenceID sent by the server.
+ * Return success if the sequenceID is one more than what we last saw on
+ * this slot, accounting for wraparound.  Increments the slot's sequence.
+ *
+ * We don't yet implement a duplicate request cache, instead we set the
+ * back channel ca_maxresponsesize_cached to zero. This is OK for now
+ * since we only currently implement idempotent callbacks anyway.
+ *
+ * We have a single slot backchannel at this time, so we don't bother
+ * checking the used_slots bit array on the table.  The lower layer guarantees
+ * a single outstanding callback request at a time.
+ */
+static __be32
+validate_seqid(const struct nfs4_slot_table *tbl, const struct nfs4_slot *slot,
+		const struct cb_sequenceargs * args)
+{
+	__be32 ret;
+
+	ret = cpu_to_be32(NFS4ERR_BADSLOT);
+	if (args->csa_slotid > tbl->server_highest_slotid)
+		goto out_err;
+
+	/* Replay */
+	if (args->csa_sequenceid == slot->seq_nr) {
+		ret = cpu_to_be32(NFS4ERR_DELAY);
+		if (nfs4_test_locked_slot(tbl, slot->slot_nr))
+			goto out_err;
+
+		/* Signal process_op to set this error on next op */
+		ret = cpu_to_be32(NFS4ERR_RETRY_UNCACHED_REP);
+		if (args->csa_cachethis == 0)
+			goto out_err;
+
+		/* Liar! We never allowed you to set csa_cachethis != 0 */
+		ret = cpu_to_be32(NFS4ERR_SEQ_FALSE_RETRY);
+		goto out_err;
+	}
+
+	/* Note: wraparound relies on seq_nr being of type u32 */
+	/* Misordered request */
+	ret = cpu_to_be32(NFS4ERR_SEQ_MISORDERED);
+	if (args->csa_sequenceid != slot->seq_nr + 1)
+		goto out_err;
+
+	return cpu_to_be32(NFS4_OK);
+
+out_err:
+	trace_nfs4_cb_seqid_err(args, ret);
+	return ret;
+}
+
+/*
+ * For each referring call triple, check the session's slot table for
+ * a match.  If the slot is in use and the sequence numbers match, the
+ * client is still waiting for a response to the original request.
+ */
+static int referring_call_exists(struct nfs_client *clp,
+				  uint32_t nrclists,
+				  struct referring_call_list *rclists,
+				  spinlock_t *lock)
+	__releases(lock)
+	__acquires(lock)
+{
+	int status = 0;
+	int found = 0;
+	int i, j;
+	struct nfs4_session *session;
+	struct nfs4_slot_table *tbl;
+	struct referring_call_list *rclist;
+	struct referring_call *ref;
+
+	/*
+	 * XXX When client trunking is implemented, this becomes
+	 * a session lookup from within the loop
+	 */
+	session = clp->cl_session;
+	tbl = &session->fc_slot_table;
+
+	for (i = 0; i < nrclists; i++) {
+		rclist = &rclists[i];
+		if (memcmp(session->sess_id.data,
+			   rclist->rcl_sessionid.data,
+			   NFS4_MAX_SESSIONID_LEN) != 0)
+			continue;
+
+		for (j = 0; j < rclist->rcl_nrefcalls; j++) {
+			ref = &rclist->rcl_refcalls[j];
+			spin_unlock(lock);
+			status = nfs4_slot_wait_on_seqid(tbl, ref->rc_slotid,
+					ref->rc_sequenceid, HZ >> 1) < 0;
+			spin_lock(lock);
+			if (status)
+				goto out;
+			found++;
+		}
+	}
+
+out:
+	return status < 0 ? status : found;
+}
+
+__be32 nfs4_callback_sequence(void *argp, void *resp,
+			      struct cb_process_state *cps)
+{
+	struct cb_sequenceargs *args = argp;
+	struct cb_sequenceres *res = resp;
+	struct nfs4_slot_table *tbl;
+	struct nfs4_slot *slot;
+	struct nfs_client *clp;
+	int ret;
+	int i;
+	__be32 status = htonl(NFS4ERR_BADSESSION);
+
+	clp = nfs4_find_client_sessionid(cps->net, args->csa_addr,
+					 &args->csa_sessionid, cps->minorversion);
+	if (clp == NULL)
+		goto out;
+
+	if (!(clp->cl_session->flags & SESSION4_BACK_CHAN))
+		goto out;
+
+	tbl = &clp->cl_session->bc_slot_table;
+
+	/* Set up res before grabbing the spinlock */
+	memcpy(&res->csr_sessionid, &args->csa_sessionid,
+	       sizeof(res->csr_sessionid));
+	res->csr_sequenceid = args->csa_sequenceid;
+	res->csr_slotid = args->csa_slotid;
+
+	spin_lock(&tbl->slot_tbl_lock);
+	/* state manager is resetting the session */
+	if (test_bit(NFS4_SLOT_TBL_DRAINING, &tbl->slot_tbl_state)) {
+		status = htonl(NFS4ERR_DELAY);
+		/* Return NFS4ERR_BADSESSION if we're draining the session
+		 * in order to reset it.
+		 */
+		if (test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state))
+			status = htonl(NFS4ERR_BADSESSION);
+		goto out_unlock;
+	}
+
+	status = htonl(NFS4ERR_BADSLOT);
+	slot = nfs4_lookup_slot(tbl, args->csa_slotid);
+	if (IS_ERR(slot))
+		goto out_unlock;
+
+	res->csr_highestslotid = tbl->server_highest_slotid;
+	res->csr_target_highestslotid = tbl->target_highest_slotid;
+
+	status = validate_seqid(tbl, slot, args);
+	if (status)
+		goto out_unlock;
+	if (!nfs4_try_to_lock_slot(tbl, slot)) {
+		status = htonl(NFS4ERR_DELAY);
+		goto out_unlock;
+	}
+	cps->slot = slot;
+
+	/* The ca_maxresponsesize_cached is 0 with no DRC */
+	if (args->csa_cachethis != 0) {
+		status = htonl(NFS4ERR_REP_TOO_BIG_TO_CACHE);
+		goto out_unlock;
+	}
+
+	/*
+	 * Check for pending referring calls.  If a match is found, a
+	 * related callback was received before the response to the original
+	 * call.
+	 */
+	ret = referring_call_exists(clp, args->csa_nrclists, args->csa_rclists,
+				    &tbl->slot_tbl_lock);
+	if (ret < 0) {
+		status = htonl(NFS4ERR_DELAY);
+		goto out_unlock;
+	}
+	cps->referring_calls = ret;
+
+	/*
+	 * RFC5661 20.9.3
+	 * If CB_SEQUENCE returns an error, then the state of the slot
+	 * (sequence ID, cached reply) MUST NOT change.
+	 */
+	slot->seq_nr = args->csa_sequenceid;
+out_unlock:
+	spin_unlock(&tbl->slot_tbl_lock);
+
+out:
+	cps->clp = clp; /* put in nfs4_callback_compound */
+	for (i = 0; i < args->csa_nrclists; i++)
+		kfree(args->csa_rclists[i].rcl_refcalls);
+	kfree(args->csa_rclists);
+
+	if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP)) {
+		cps->drc_status = status;
+		status = 0;
+	} else
+		res->csr_status = status;
+
+	trace_nfs4_cb_sequence(args, res, status);
+	return status;
+}
+
+static bool
+validate_bitmap_values(unsigned int mask)
+{
+	return (mask & ~RCA4_TYPE_MASK_ALL) == 0;
+}
+
+__be32 nfs4_callback_recallany(void *argp, void *resp,
+			       struct cb_process_state *cps)
+{
+	struct cb_recallanyargs *args = argp;
+	__be32 status;
+	fmode_t flags = 0;
+	bool schedule_manager = false;
+
+	status = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
+	if (!cps->clp) /* set in cb_sequence */
+		goto out;
+
+	dprintk_rcu("NFS: RECALL_ANY callback request from %s\n",
+		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
+
+	status = cpu_to_be32(NFS4ERR_INVAL);
+	if (!validate_bitmap_values(args->craa_type_mask))
+		goto out;
+
+	status = cpu_to_be32(NFS4_OK);
+	if (args->craa_type_mask & BIT(RCA4_TYPE_MASK_RDATA_DLG))
+		flags = FMODE_READ;
+	if (args->craa_type_mask & BIT(RCA4_TYPE_MASK_WDATA_DLG))
+		flags |= FMODE_WRITE;
+	if (flags)
+		nfs_expire_unused_delegation_types(cps->clp, flags);
+
+	if (args->craa_type_mask & BIT(RCA4_TYPE_MASK_FILE_LAYOUT))
+		pnfs_recall_all_layouts(cps->clp, cps);
+
+	if (args->craa_type_mask & BIT(PNFS_FF_RCA4_TYPE_MASK_READ)) {
+		set_bit(NFS4CLNT_RECALL_ANY_LAYOUT_READ, &cps->clp->cl_state);
+		schedule_manager = true;
+	}
+	if (args->craa_type_mask & BIT(PNFS_FF_RCA4_TYPE_MASK_RW)) {
+		set_bit(NFS4CLNT_RECALL_ANY_LAYOUT_RW, &cps->clp->cl_state);
+		schedule_manager = true;
+	}
+	if (schedule_manager)
+		nfs4_schedule_state_manager(cps->clp);
+
+out:
+	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
+	return status;
+}
+
+/* Reduce the fore channel's max_slots to the target value */
+__be32 nfs4_callback_recallslot(void *argp, void *resp,
+				struct cb_process_state *cps)
+{
+	struct cb_recallslotargs *args = argp;
+	struct nfs4_slot_table *fc_tbl;
+	__be32 status;
+
+	status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
+	if (!cps->clp) /* set in cb_sequence */
+		goto out;
+
+	dprintk_rcu("NFS: CB_RECALL_SLOT request from %s target highest slotid %u\n",
+		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR),
+		args->crsa_target_highest_slotid);
+
+	fc_tbl = &cps->clp->cl_session->fc_slot_table;
+
+	status = htonl(NFS4_OK);
+
+	nfs41_set_target_slotid(fc_tbl, args->crsa_target_highest_slotid);
+	nfs41_notify_server(cps->clp);
+out:
+	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
+	return status;
+}
+
+__be32 nfs4_callback_notify_lock(void *argp, void *resp,
+				 struct cb_process_state *cps)
+{
+	struct cb_notify_lock_args *args = argp;
+
+	if (!cps->clp) /* set in cb_sequence */
+		return htonl(NFS4ERR_OP_NOT_IN_SESSION);
+
+	dprintk_rcu("NFS: CB_NOTIFY_LOCK request from %s\n",
+		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
+
+	/* Don't wake anybody if the string looked bogus */
+	if (args->cbnl_valid)
+		__wake_up(&cps->clp->cl_lock_waitq, TASK_NORMAL, 0, args);
+
+	return htonl(NFS4_OK);
+}
+#ifdef CONFIG_NFS_V4_2
+static void nfs4_copy_cb_args(struct nfs4_copy_state *cp_state,
+				struct cb_offloadargs *args)
+{
+	cp_state->count = args->wr_count;
+	cp_state->error = args->error;
+	if (!args->error) {
+		cp_state->verf.committed = args->wr_writeverf.committed;
+		memcpy(&cp_state->verf.verifier.data[0],
+			&args->wr_writeverf.verifier.data[0],
+			NFS4_VERIFIER_SIZE);
+	}
+}
+
+__be32 nfs4_callback_offload(void *data, void *dummy,
+			     struct cb_process_state *cps)
+{
+	struct cb_offloadargs *args = data;
+	struct nfs_server *server;
+	struct nfs4_copy_state *copy, *tmp_copy;
+	bool found = false;
+
+	copy = kzalloc_obj(struct nfs4_copy_state);
+	if (!copy)
+		return cpu_to_be32(NFS4ERR_DELAY);
+
+	spin_lock(&cps->clp->cl_lock);
+	rcu_read_lock();
+	list_for_each_entry_rcu(server, &cps->clp->cl_superblocks,
+				client_link) {
+		list_for_each_entry(tmp_copy, &server->ss_copies, copies) {
+			if (memcmp(args->coa_stateid.other,
+					tmp_copy->stateid.other,
+					sizeof(args->coa_stateid.other)))
+				continue;
+			nfs4_copy_cb_args(tmp_copy, args);
+			complete(&tmp_copy->completion);
+			found = true;
+			goto out;
+		}
+	}
+out:
+	rcu_read_unlock();
+	if (!found) {
+		memcpy(&copy->stateid, &args->coa_stateid, NFS4_STATEID_SIZE);
+		nfs4_copy_cb_args(copy, args);
+		list_add_tail(&copy->copies, &cps->clp->pending_cb_stateids);
+	} else
+		kfree(copy);
+	spin_unlock(&cps->clp->cl_lock);
+
+	trace_nfs4_cb_offload(&args->coa_fh, &args->coa_stateid,
+			args->wr_count, args->error,
+			args->wr_writeverf.committed);
+	return 0;
+}
+#endif /* CONFIG_NFS_V4_2 */