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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /*
  *  fs/nfs/nfs4state.c
  *
  *  Client-side XDR for NFSv4.
  *
  *  Copyright (c) 2002 The Regents of the University of Michigan.
  *  All rights reserved.
  *
  *  Kendrick Smith <kmsmith@umich.edu>
  *
  *  Redistribution and use in source and binary forms, with or without
  *  modification, are permitted provided that the following conditions
  *  are met:
  *
  *  1. Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
  *     documentation and/or other materials provided with the distribution.
  *  3. Neither the name of the University nor the names of its
  *     contributors may be used to endorse or promote products derived
  *     from this software without specific prior written permission.
  *
  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * Implementation of the NFSv4 state model.  For the time being,
  * this is minimal, but will be made much more complex in a
  * subsequent patch.
  */
 
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/nfs_fs.h>
 #include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/random.h>
 #include <linux/ratelimit.h>
 #include <linux/workqueue.h>
 #include <linux/bitops.h>
 #include <linux/jiffies.h>
 #include <linux/sched/mm.h>
 
 #include <linux/sunrpc/clnt.h>
 
 #include "nfs4_fs.h"
 #include "callback.h"
 #include "delegation.h"
 #include "internal.h"
 #include "nfs4idmap.h"
 #include "nfs4session.h"
 #include "pnfs.h"
 #include "netns.h"
 #include "nfs4trace.h"
 
 #define NFSDBG_FACILITY     NFSDBG_STATE
 
 #define OPENOWNER_POOL_SIZE 8
 
 const nfs4_stateid zero_stateid = {
     { .data = { 0 } },
     .type = NFS4_SPECIAL_STATEID_TYPE,
 };
 const nfs4_stateid invalid_stateid = {
     {
         /* Funky initialiser keeps older gcc versions happy */
         .data = { 0xff, 0xff, 0xff, 0xff, 0 },
     },
     .type = NFS4_INVALID_STATEID_TYPE,
 };
 
 const nfs4_stateid current_stateid = {
     {
         /* Funky initialiser keeps older gcc versions happy */
         .data = { 0x0, 0x0, 0x0, 0x1, 0 },
     },
     .type = NFS4_SPECIAL_STATEID_TYPE,
 };
 
 static DEFINE_MUTEX(nfs_clid_init_mutex);
 
 static int nfs4_setup_state_renewal(struct nfs_client *clp)
 {
     int status;
     struct nfs_fsinfo fsinfo;
 
     if (!test_bit(NFS_CS_CHECK_LEASE_TIME, &clp->cl_res_state)) {
         nfs4_schedule_state_renewal(clp);
         return 0;
     }
 
     status = nfs4_proc_get_lease_time(clp, &fsinfo);
     if (status == 0) {
         nfs4_set_lease_period(clp, fsinfo.lease_time * HZ);
         nfs4_schedule_state_renewal(clp);
     }
 
     return status;
 }
 
 int nfs4_init_clientid(struct nfs_client *clp, const struct cred *cred)
 {
     struct nfs4_setclientid_res clid = {
         .clientid = clp->cl_clientid,
         .confirm = clp->cl_confirm,
     };
     unsigned short port;
     int status;
     struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
 
     if (test_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state))
         goto do_confirm;
     port = nn->nfs_callback_tcpport;
     if (clp->cl_addr.ss_family == AF_INET6)
         port = nn->nfs_callback_tcpport6;
 
     status = nfs4_proc_setclientid(clp, NFS4_CALLBACK, port, cred, &clid);
     if (status != 0)
         goto out;
     clp->cl_clientid = clid.clientid;
     clp->cl_confirm = clid.confirm;
     set_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
 do_confirm:
     status = nfs4_proc_setclientid_confirm(clp, &clid, cred);
     if (status != 0)
         goto out;
     clear_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
     nfs4_setup_state_renewal(clp);
 out:
     return status;
 }
 
 /**
  * nfs40_discover_server_trunking - Detect server IP address trunking (mv0)
  *
  * @clp: nfs_client under test
  * @result: OUT: found nfs_client, or clp
  * @cred: credential to use for trunking test
  *
  * Returns zero, a negative errno, or a negative NFS4ERR status.
  * If zero is returned, an nfs_client pointer is planted in
  * "result".
  *
  * Note: The returned client may not yet be marked ready.
  */
 int nfs40_discover_server_trunking(struct nfs_client *clp,
                    struct nfs_client **result,
                    const struct cred *cred)
 {
     struct nfs4_setclientid_res clid = {
         .clientid = clp->cl_clientid,
         .confirm = clp->cl_confirm,
     };
     struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
     unsigned short port;
     int status;
 
     port = nn->nfs_callback_tcpport;
     if (clp->cl_addr.ss_family == AF_INET6)
         port = nn->nfs_callback_tcpport6;
 
     status = nfs4_proc_setclientid(clp, NFS4_CALLBACK, port, cred, &clid);
     if (status != 0)
         goto out;
     clp->cl_clientid = clid.clientid;
     clp->cl_confirm = clid.confirm;
 
     status = nfs40_walk_client_list(clp, result, cred);
     if (status == 0) {
         /* Sustain the lease, even if it's empty.  If the clientid4
          * goes stale it's of no use for trunking discovery. */
         nfs4_schedule_state_renewal(*result);
 
         /* If the client state need to recover, do it. */
         if (clp->cl_state)
             nfs4_schedule_state_manager(clp);
     }
 out:
     return status;
 }
 
 const struct cred *nfs4_get_machine_cred(struct nfs_client *clp)
 {
     return get_cred(rpc_machine_cred());
 }
 
 static void nfs4_root_machine_cred(struct nfs_client *clp)
 {
 
     /* Force root creds instead of machine */
     clp->cl_principal = NULL;
     clp->cl_rpcclient->cl_principal = NULL;
 }
 
 static const struct cred *
 nfs4_get_renew_cred_server_locked(struct nfs_server *server)
 {
     const struct cred *cred = NULL;
     struct nfs4_state_owner *sp;
     struct rb_node *pos;
 
     for (pos = rb_first(&server->state_owners);
          pos != NULL;
          pos = rb_next(pos)) {
         sp = rb_entry(pos, struct nfs4_state_owner, so_server_node);
         if (list_empty(&sp->so_states))
             continue;
         cred = get_cred(sp->so_cred);
         break;
     }
     return cred;
 }
 
 /**
  * nfs4_get_renew_cred - Acquire credential for a renew operation
  * @clp: client state handle
  *
  * Returns an rpc_cred with reference count bumped, or NULL.
  * Caller must hold clp->cl_lock.
  */
 const struct cred *nfs4_get_renew_cred(struct nfs_client *clp)
 {
     const struct cred *cred = NULL;
     struct nfs_server *server;
 
     /* Use machine credentials if available */
     cred = nfs4_get_machine_cred(clp);
     if (cred != NULL)
         goto out;
 
     spin_lock(&clp->cl_lock);
     rcu_read_lock();
     list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
         cred = nfs4_get_renew_cred_server_locked(server);
         if (cred != NULL)
             break;
     }
     rcu_read_unlock();
     spin_unlock(&clp->cl_lock);
 
 out:
     return cred;
 }
 
 static void nfs4_end_drain_slot_table(struct nfs4_slot_table *tbl)
 {
     if (test_and_clear_bit(NFS4_SLOT_TBL_DRAINING, &tbl->slot_tbl_state)) {
         spin_lock(&tbl->slot_tbl_lock);
         nfs41_wake_slot_table(tbl);
         spin_unlock(&tbl->slot_tbl_lock);
     }
 }
 
 static void nfs4_end_drain_session(struct nfs_client *clp)
 {
     struct nfs4_session *ses = clp->cl_session;
 
     if (clp->cl_slot_tbl) {
         nfs4_end_drain_slot_table(clp->cl_slot_tbl);
         return;
     }
 
     if (ses != NULL) {
         nfs4_end_drain_slot_table(&ses->bc_slot_table);
         nfs4_end_drain_slot_table(&ses->fc_slot_table);
     }
 }
 
 static int nfs4_drain_slot_tbl(struct nfs4_slot_table *tbl)
 {
     set_bit(NFS4_SLOT_TBL_DRAINING, &tbl->slot_tbl_state);
     spin_lock(&tbl->slot_tbl_lock);
     if (tbl->highest_used_slotid != NFS4_NO_SLOT) {
         reinit_completion(&tbl->complete);
         spin_unlock(&tbl->slot_tbl_lock);
         return wait_for_completion_interruptible(&tbl->complete);
     }
     spin_unlock(&tbl->slot_tbl_lock);
     return 0;
 }
 
 static int nfs4_begin_drain_session(struct nfs_client *clp)
 {
     struct nfs4_session *ses = clp->cl_session;
     int ret;
 
     if (clp->cl_slot_tbl)
         return nfs4_drain_slot_tbl(clp->cl_slot_tbl);
 
     /* back channel */
     ret = nfs4_drain_slot_tbl(&ses->bc_slot_table);
     if (ret)
         return ret;
     /* fore channel */
     return nfs4_drain_slot_tbl(&ses->fc_slot_table);
 }
 
 #if defined(CONFIG_NFS_V4_1)
 
 static void nfs41_finish_session_reset(struct nfs_client *clp)
 {
     clear_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
     clear_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state);
     /* create_session negotiated new slot table */
     clear_bit(NFS4CLNT_BIND_CONN_TO_SESSION, &clp->cl_state);
     nfs4_setup_state_renewal(clp);
 }
 
 int nfs41_init_clientid(struct nfs_client *clp, const struct cred *cred)
 {
     int status;
 
     if (test_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state))
         goto do_confirm;
     status = nfs4_proc_exchange_id(clp, cred);
     if (status != 0)
         goto out;
     set_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
 do_confirm:
     status = nfs4_proc_create_session(clp, cred);
     if (status != 0)
         goto out;
     nfs41_finish_session_reset(clp);
     nfs_mark_client_ready(clp, NFS_CS_READY);
 out:
     return status;
 }
 
 /**
  * nfs41_discover_server_trunking - Detect server IP address trunking (mv1)
  *
  * @clp: nfs_client under test
  * @result: OUT: found nfs_client, or clp
  * @cred: credential to use for trunking test
  *
  * Returns NFS4_OK, a negative errno, or a negative NFS4ERR status.
  * If NFS4_OK is returned, an nfs_client pointer is planted in
  * "result".
  *
  * Note: The returned client may not yet be marked ready.
  */
 int nfs41_discover_server_trunking(struct nfs_client *clp,
                    struct nfs_client **result,
                    const struct cred *cred)
 {
     int status;
 
     status = nfs4_proc_exchange_id(clp, cred);
     if (status != NFS4_OK)
         return status;
 
     status = nfs41_walk_client_list(clp, result, cred);
     if (status < 0)
         return status;
     if (clp != *result)
         return 0;
 
     /*
      * Purge state if the client id was established in a prior
      * instance and the client id could not have arrived on the
      * server via Transparent State Migration.
      */
     if (clp->cl_exchange_flags & EXCHGID4_FLAG_CONFIRMED_R) {
         if (!test_bit(NFS_CS_TSM_POSSIBLE, &clp->cl_flags))
             set_bit(NFS4CLNT_PURGE_STATE, &clp->cl_state);
         else
             set_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
     }
     nfs4_schedule_state_manager(clp);
     status = nfs_wait_client_init_complete(clp);
     if (status < 0)
         nfs_put_client(clp);
     return status;
 }
 
 #endif /* CONFIG_NFS_V4_1 */
 
 /**
  * nfs4_get_clid_cred - Acquire credential for a setclientid operation
  * @clp: client state handle
  *
  * Returns a cred with reference count bumped, or NULL.
  */
 const struct cred *nfs4_get_clid_cred(struct nfs_client *clp)
 {
     const struct cred *cred;
 
     cred = nfs4_get_machine_cred(clp);
     return cred;
 }
 
 static struct nfs4_state_owner *
 nfs4_find_state_owner_locked(struct nfs_server *server, const struct cred *cred)
 {
     struct rb_node **p = &server->state_owners.rb_node,
                *parent = NULL;
     struct nfs4_state_owner *sp;
     int cmp;
 
     while (*p != NULL) {
         parent = *p;
         sp = rb_entry(parent, struct nfs4_state_owner, so_server_node);
         cmp = cred_fscmp(cred, sp->so_cred);
 
         if (cmp < 0)
             p = &parent->rb_left;
         else if (cmp > 0)
             p = &parent->rb_right;
         else {
             if (!list_empty(&sp->so_lru))
                 list_del_init(&sp->so_lru);
             atomic_inc(&sp->so_count);
             return sp;
         }
     }
     return NULL;
 }
 
 static struct nfs4_state_owner *
 nfs4_insert_state_owner_locked(struct nfs4_state_owner *new)
 {
     struct nfs_server *server = new->so_server;
     struct rb_node **p = &server->state_owners.rb_node,
                *parent = NULL;
     struct nfs4_state_owner *sp;
     int cmp;
 
     while (*p != NULL) {
         parent = *p;
         sp = rb_entry(parent, struct nfs4_state_owner, so_server_node);
         cmp = cred_fscmp(new->so_cred, sp->so_cred);
 
         if (cmp < 0)
             p = &parent->rb_left;
         else if (cmp > 0)
             p = &parent->rb_right;
         else {
             if (!list_empty(&sp->so_lru))
                 list_del_init(&sp->so_lru);
             atomic_inc(&sp->so_count);
             return sp;
         }
     }
     rb_link_node(&new->so_server_node, parent, p);
     rb_insert_color(&new->so_server_node, &server->state_owners);
     return new;
 }
 
 static void
 nfs4_remove_state_owner_locked(struct nfs4_state_owner *sp)
 {
     struct nfs_server *server = sp->so_server;
 
     if (!RB_EMPTY_NODE(&sp->so_server_node))
         rb_erase(&sp->so_server_node, &server->state_owners);
 }
 
 static void
 nfs4_init_seqid_counter(struct nfs_seqid_counter *sc)
 {
     sc->create_time = ktime_get();
     sc->flags = 0;
     sc->counter = 0;
     spin_lock_init(&sc->lock);
     INIT_LIST_HEAD(&sc->list);
     rpc_init_wait_queue(&sc->wait, "Seqid_waitqueue");
 }
 
 static void
 nfs4_destroy_seqid_counter(struct nfs_seqid_counter *sc)
 {
     rpc_destroy_wait_queue(&sc->wait);
 }
 
 /*
  * nfs4_alloc_state_owner(): this is called on the OPEN or CREATE path to
  * create a new state_owner.
  *
  */
 static struct nfs4_state_owner *
 nfs4_alloc_state_owner(struct nfs_server *server,
         const struct cred *cred,
         gfp_t gfp_flags)
 {
     struct nfs4_state_owner *sp;
 
     sp = kzalloc(sizeof(*sp), gfp_flags);
     if (!sp)
         return NULL;
     sp->so_seqid.owner_id = ida_simple_get(&server->openowner_id, 0, 0,
                         gfp_flags);
     if (sp->so_seqid.owner_id < 0) {
         kfree(sp);
         return NULL;
     }
     sp->so_server = server;
     sp->so_cred = get_cred(cred);
     spin_lock_init(&sp->so_lock);
     INIT_LIST_HEAD(&sp->so_states);
     nfs4_init_seqid_counter(&sp->so_seqid);
     atomic_set(&sp->so_count, 1);
     INIT_LIST_HEAD(&sp->so_lru);
     seqcount_spinlock_init(&sp->so_reclaim_seqcount, &sp->so_lock);
     mutex_init(&sp->so_delegreturn_mutex);
     return sp;
 }
 
 static void
 nfs4_reset_state_owner(struct nfs4_state_owner *sp)
 {
     /* This state_owner is no longer usable, but must
      * remain in place so that state recovery can find it
      * and the opens associated with it.
      * It may also be used for new 'open' request to
      * return a delegation to the server.
      * So update the 'create_time' so that it looks like
      * a new state_owner.  This will cause the server to
      * request an OPEN_CONFIRM to start a new sequence.
      */
     sp->so_seqid.create_time = ktime_get();
 }
 
 static void nfs4_free_state_owner(struct nfs4_state_owner *sp)
 {
     nfs4_destroy_seqid_counter(&sp->so_seqid);
     put_cred(sp->so_cred);
     ida_simple_remove(&sp->so_server->openowner_id, sp->so_seqid.owner_id);
     kfree(sp);
 }
 
 static void nfs4_gc_state_owners(struct nfs_server *server)
 {
     struct nfs_client *clp = server->nfs_client;
     struct nfs4_state_owner *sp, *tmp;
     unsigned long time_min, time_max;
     LIST_HEAD(doomed);
 
     spin_lock(&clp->cl_lock);
     time_max = jiffies;
     time_min = (long)time_max - (long)clp->cl_lease_time;
     list_for_each_entry_safe(sp, tmp, &server->state_owners_lru, so_lru) {
         /* NB: LRU is sorted so that oldest is at the head */
         if (time_in_range(sp->so_expires, time_min, time_max))
             break;
         list_move(&sp->so_lru, &doomed);
         nfs4_remove_state_owner_locked(sp);
     }
     spin_unlock(&clp->cl_lock);
 
     list_for_each_entry_safe(sp, tmp, &doomed, so_lru) {
         list_del(&sp->so_lru);
         nfs4_free_state_owner(sp);
     }
 }
 
 /**
  * nfs4_get_state_owner - Look up a state owner given a credential
  * @server: nfs_server to search
  * @cred: RPC credential to match
  * @gfp_flags: allocation mode
  *
  * Returns a pointer to an instantiated nfs4_state_owner struct, or NULL.
  */
 struct nfs4_state_owner *nfs4_get_state_owner(struct nfs_server *server,
                           const struct cred *cred,
                           gfp_t gfp_flags)
 {
     struct nfs_client *clp = server->nfs_client;
     struct nfs4_state_owner *sp, *new;
 
     spin_lock(&clp->cl_lock);
     sp = nfs4_find_state_owner_locked(server, cred);
     spin_unlock(&clp->cl_lock);
     if (sp != NULL)
         goto out;
     new = nfs4_alloc_state_owner(server, cred, gfp_flags);
     if (new == NULL)
         goto out;
     spin_lock(&clp->cl_lock);
     sp = nfs4_insert_state_owner_locked(new);
     spin_unlock(&clp->cl_lock);
     if (sp != new)
         nfs4_free_state_owner(new);
 out:
     nfs4_gc_state_owners(server);
     return sp;
 }
 
 /**
  * nfs4_put_state_owner - Release a nfs4_state_owner
  * @sp: state owner data to release
  *
  * Note that we keep released state owners on an LRU
  * list.
  * This caches valid state owners so that they can be
  * reused, to avoid the OPEN_CONFIRM on minor version 0.
  * It also pins the uniquifier of dropped state owners for
  * a while, to ensure that those state owner names are
  * never reused.
  */
 void nfs4_put_state_owner(struct nfs4_state_owner *sp)
 {
     struct nfs_server *server = sp->so_server;
     struct nfs_client *clp = server->nfs_client;
 
     if (!atomic_dec_and_lock(&sp->so_count, &clp->cl_lock))
         return;
 
     sp->so_expires = jiffies;
     list_add_tail(&sp->so_lru, &server->state_owners_lru);
     spin_unlock(&clp->cl_lock);
 }
 
 /**
  * nfs4_purge_state_owners - Release all cached state owners
  * @server: nfs_server with cached state owners to release
  * @head: resulting list of state owners
  *
  * Called at umount time.  Remaining state owners will be on
  * the LRU with ref count of zero.
  * Note that the state owners are not freed, but are added
  * to the list @head, which can later be used as an argument
  * to nfs4_free_state_owners.
  */
 void nfs4_purge_state_owners(struct nfs_server *server, struct list_head *head)
 {
     struct nfs_client *clp = server->nfs_client;
     struct nfs4_state_owner *sp, *tmp;
 
     spin_lock(&clp->cl_lock);
     list_for_each_entry_safe(sp, tmp, &server->state_owners_lru, so_lru) {
         list_move(&sp->so_lru, head);
         nfs4_remove_state_owner_locked(sp);
     }
     spin_unlock(&clp->cl_lock);
 }
 
 /**
  * nfs4_free_state_owners - Release all cached state owners
  * @head: resulting list of state owners
  *
  * Frees a list of state owners that was generated by
  * nfs4_purge_state_owners
  */
 void nfs4_free_state_owners(struct list_head *head)
 {
     struct nfs4_state_owner *sp, *tmp;
 
     list_for_each_entry_safe(sp, tmp, head, so_lru) {
         list_del(&sp->so_lru);
         nfs4_free_state_owner(sp);
     }
 }
 
 static struct nfs4_state *
 nfs4_alloc_open_state(void)
 {
     struct nfs4_state *state;
 
     state = kzalloc(sizeof(*state), GFP_KERNEL_ACCOUNT);
     if (!state)
         return NULL;
     refcount_set(&state->count, 1);
     INIT_LIST_HEAD(&state->lock_states);
     spin_lock_init(&state->state_lock);
     seqlock_init(&state->seqlock);
     init_waitqueue_head(&state->waitq);
     return state;
 }
 
 void
 nfs4_state_set_mode_locked(struct nfs4_state *state, fmode_t fmode)
 {
     if (state->state == fmode)
         return;
     /* NB! List reordering - see the reclaim code for why.  */
     if ((fmode & FMODE_WRITE) != (state->state & FMODE_WRITE)) {
         if (fmode & FMODE_WRITE)
             list_move(&state->open_states, &state->owner->so_states);
         else
             list_move_tail(&state->open_states, &state->owner->so_states);
     }
     state->state = fmode;
 }
 
 static struct nfs4_state *
 __nfs4_find_state_byowner(struct inode *inode, struct nfs4_state_owner *owner)
 {
     struct nfs_inode *nfsi = NFS_I(inode);
     struct nfs4_state *state;
 
     list_for_each_entry_rcu(state, &nfsi->open_states, inode_states) {
         if (state->owner != owner)
             continue;
         if (!nfs4_valid_open_stateid(state))
             continue;
         if (refcount_inc_not_zero(&state->count))
             return state;
     }
     return NULL;
 }
 
 static void
 nfs4_free_open_state(struct nfs4_state *state)
 {
     kfree_rcu(state, rcu_head);
 }
 
 struct nfs4_state *
 nfs4_get_open_state(struct inode *inode, struct nfs4_state_owner *owner)
 {
     struct nfs4_state *state, *new;
     struct nfs_inode *nfsi = NFS_I(inode);
 
     rcu_read_lock();
     state = __nfs4_find_state_byowner(inode, owner);
     rcu_read_unlock();
     if (state)
         goto out;
     new = nfs4_alloc_open_state();
     spin_lock(&owner->so_lock);
     spin_lock(&inode->i_lock);
     state = __nfs4_find_state_byowner(inode, owner);
     if (state == NULL && new != NULL) {
         state = new;
         state->owner = owner;
         atomic_inc(&owner->so_count);
         ihold(inode);
         state->inode = inode;
         list_add_rcu(&state->inode_states, &nfsi->open_states);
         spin_unlock(&inode->i_lock);
         /* Note: The reclaim code dictates that we add stateless
          * and read-only stateids to the end of the list */
         list_add_tail(&state->open_states, &owner->so_states);
         spin_unlock(&owner->so_lock);
     } else {
         spin_unlock(&inode->i_lock);
         spin_unlock(&owner->so_lock);
         if (new)
             nfs4_free_open_state(new);
     }
 out:
     return state;
 }
 
 void nfs4_put_open_state(struct nfs4_state *state)
 {
     struct inode *inode = state->inode;
     struct nfs4_state_owner *owner = state->owner;
 
     if (!refcount_dec_and_lock(&state->count, &owner->so_lock))
         return;
     spin_lock(&inode->i_lock);
     list_del_rcu(&state->inode_states);
     list_del(&state->open_states);
     spin_unlock(&inode->i_lock);
     spin_unlock(&owner->so_lock);
     nfs4_inode_return_delegation_on_close(inode);
     iput(inode);
     nfs4_free_open_state(state);
     nfs4_put_state_owner(owner);
 }
 
 /*
  * Close the current file.
  */
 static void __nfs4_close(struct nfs4_state *state,
         fmode_t fmode, gfp_t gfp_mask, int wait)
 {
     struct nfs4_state_owner *owner = state->owner;
     int call_close = 0;
     fmode_t newstate;
 
     atomic_inc(&owner->so_count);
     /* Protect against nfs4_find_state() */
     spin_lock(&owner->so_lock);
     switch (fmode & (FMODE_READ | FMODE_WRITE)) {
         case FMODE_READ:
             state->n_rdonly--;
             break;
         case FMODE_WRITE:
             state->n_wronly--;
             break;
         case FMODE_READ|FMODE_WRITE:
             state->n_rdwr--;
     }
     newstate = FMODE_READ|FMODE_WRITE;
     if (state->n_rdwr == 0) {
         if (state->n_rdonly == 0) {
             newstate &= ~FMODE_READ;
             call_close |= test_bit(NFS_O_RDONLY_STATE, &state->flags);
             call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
         }
         if (state->n_wronly == 0) {
             newstate &= ~FMODE_WRITE;
             call_close |= test_bit(NFS_O_WRONLY_STATE, &state->flags);
             call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
         }
         if (newstate == 0)
             clear_bit(NFS_DELEGATED_STATE, &state->flags);
     }
     nfs4_state_set_mode_locked(state, newstate);
     spin_unlock(&owner->so_lock);
 
     if (!call_close) {
         nfs4_put_open_state(state);
         nfs4_put_state_owner(owner);
     } else
         nfs4_do_close(state, gfp_mask, wait);
 }
 
 void nfs4_close_state(struct nfs4_state *state, fmode_t fmode)
 {
     __nfs4_close(state, fmode, GFP_KERNEL, 0);
 }
 
 void nfs4_close_sync(struct nfs4_state *state, fmode_t fmode)
 {
     __nfs4_close(state, fmode, GFP_KERNEL, 1);
 }
 
 /*
  * Search the state->lock_states for an existing lock_owner
  * that is compatible with either of the given owners.
  * If the second is non-zero, then the first refers to a Posix-lock
  * owner (current->files) and the second refers to a flock/OFD
  * owner (struct file*).  In that case, prefer a match for the first
  * owner.
  * If both sorts of locks are held on the one file we cannot know
  * which stateid was intended to be used, so a "correct" choice cannot
  * be made.  Failing that, a "consistent" choice is preferable.  The
  * consistent choice we make is to prefer the first owner, that of a
  * Posix lock.
  */
 static struct nfs4_lock_state *
 __nfs4_find_lock_state(struct nfs4_state *state,
                fl_owner_t fl_owner, fl_owner_t fl_owner2)
 {
     struct nfs4_lock_state *pos, *ret = NULL;
     list_for_each_entry(pos, &state->lock_states, ls_locks) {
         if (pos->ls_owner == fl_owner) {
             ret = pos;
             break;
         }
         if (pos->ls_owner == fl_owner2)
             ret = pos;
     }
     if (ret)
         refcount_inc(&ret->ls_count);
     return ret;
 }
 
 /*
  * Return a compatible lock_state. If no initialized lock_state structure
  * exists, return an uninitialized one.
  *
  */
 static struct nfs4_lock_state *nfs4_alloc_lock_state(struct nfs4_state *state, fl_owner_t fl_owner)
 {
     struct nfs4_lock_state *lsp;
     struct nfs_server *server = state->owner->so_server;
 
     lsp = kzalloc(sizeof(*lsp), GFP_KERNEL_ACCOUNT);
     if (lsp == NULL)
         return NULL;
     nfs4_init_seqid_counter(&lsp->ls_seqid);
     refcount_set(&lsp->ls_count, 1);
     lsp->ls_state = state;
     lsp->ls_owner = fl_owner;
     lsp->ls_seqid.owner_id = ida_simple_get(&server->lockowner_id,
                         0, 0, GFP_KERNEL_ACCOUNT);
     if (lsp->ls_seqid.owner_id < 0)
         goto out_free;
     INIT_LIST_HEAD(&lsp->ls_locks);
     return lsp;
 out_free:
     kfree(lsp);
     return NULL;
 }
 
 void nfs4_free_lock_state(struct nfs_server *server, struct nfs4_lock_state *lsp)
 {
     ida_simple_remove(&server->lockowner_id, lsp->ls_seqid.owner_id);
     nfs4_destroy_seqid_counter(&lsp->ls_seqid);
     kfree(lsp);
 }
 
 /*
  * Return a compatible lock_state. If no initialized lock_state structure
  * exists, return an uninitialized one.
  *
  */
 static struct nfs4_lock_state *nfs4_get_lock_state(struct nfs4_state *state, fl_owner_t owner)
 {
     struct nfs4_lock_state *lsp, *new = NULL;
     
     for(;;) {
         spin_lock(&state->state_lock);
         lsp = __nfs4_find_lock_state(state, owner, NULL);
         if (lsp != NULL)
             break;
         if (new != NULL) {
             list_add(&new->ls_locks, &state->lock_states);
             set_bit(LK_STATE_IN_USE, &state->flags);
             lsp = new;
             new = NULL;
             break;
         }
         spin_unlock(&state->state_lock);
         new = nfs4_alloc_lock_state(state, owner);
         if (new == NULL)
             return NULL;
     }
     spin_unlock(&state->state_lock);
     if (new != NULL)
         nfs4_free_lock_state(state->owner->so_server, new);
     return lsp;
 }
 
 /*
  * Release reference to lock_state, and free it if we see that
  * it is no longer in use
  */
 void nfs4_put_lock_state(struct nfs4_lock_state *lsp)
 {
     struct nfs_server *server;
     struct nfs4_state *state;
 
     if (lsp == NULL)
         return;
     state = lsp->ls_state;
     if (!refcount_dec_and_lock(&lsp->ls_count, &state->state_lock))
         return;
     list_del(&lsp->ls_locks);
     if (list_empty(&state->lock_states))
         clear_bit(LK_STATE_IN_USE, &state->flags);
     spin_unlock(&state->state_lock);
     server = state->owner->so_server;
     if (test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags)) {
         struct nfs_client *clp = server->nfs_client;
 
         clp->cl_mvops->free_lock_state(server, lsp);
     } else
         nfs4_free_lock_state(server, lsp);
 }
 
 static void nfs4_fl_copy_lock(struct file_lock *dst, struct file_lock *src)
 {
     struct nfs4_lock_state *lsp = src->fl_u.nfs4_fl.owner;
 
     dst->fl_u.nfs4_fl.owner = lsp;
     refcount_inc(&lsp->ls_count);
 }
 
 static void nfs4_fl_release_lock(struct file_lock *fl)
 {
     nfs4_put_lock_state(fl->fl_u.nfs4_fl.owner);
 }
 
 static const struct file_lock_operations nfs4_fl_lock_ops = {
     .fl_copy_lock = nfs4_fl_copy_lock,
     .fl_release_private = nfs4_fl_release_lock,
 };
 
 int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl)
 {
     struct nfs4_lock_state *lsp;
 
     if (fl->fl_ops != NULL)
         return 0;
     lsp = nfs4_get_lock_state(state, fl->fl_owner);
     if (lsp == NULL)
         return -ENOMEM;
     fl->fl_u.nfs4_fl.owner = lsp;
     fl->fl_ops = &nfs4_fl_lock_ops;
     return 0;
 }
 
 static int nfs4_copy_lock_stateid(nfs4_stateid *dst,
         struct nfs4_state *state,
         const struct nfs_lock_context *l_ctx)
 {
     struct nfs4_lock_state *lsp;
     fl_owner_t fl_owner, fl_flock_owner;
     int ret = -ENOENT;
 
     if (l_ctx == NULL)
         goto out;
 
     if (test_bit(LK_STATE_IN_USE, &state->flags) == 0)
         goto out;
 
     fl_owner = l_ctx->lockowner;
     fl_flock_owner = l_ctx->open_context->flock_owner;
 
     spin_lock(&state->state_lock);
     lsp = __nfs4_find_lock_state(state, fl_owner, fl_flock_owner);
     if (lsp && test_bit(NFS_LOCK_LOST, &lsp->ls_flags))
         ret = -EIO;
     else if (lsp != NULL && test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags) != 0) {
         nfs4_stateid_copy(dst, &lsp->ls_stateid);
         ret = 0;
     }
     spin_unlock(&state->state_lock);
     nfs4_put_lock_state(lsp);
 out:
     return ret;
 }
 
 bool nfs4_copy_open_stateid(nfs4_stateid *dst, struct nfs4_state *state)
 {
     bool ret;
     const nfs4_stateid *src;
     int seq;
 
     do {
         ret = false;
         src = &zero_stateid;
         seq = read_seqbegin(&state->seqlock);
         if (test_bit(NFS_OPEN_STATE, &state->flags)) {
             src = &state->open_stateid;
             ret = true;
         }
         nfs4_stateid_copy(dst, src);
     } while (read_seqretry(&state->seqlock, seq));
     return ret;
 }
 
 /*
  * Byte-range lock aware utility to initialize the stateid of read/write
  * requests.
  */
 int nfs4_select_rw_stateid(struct nfs4_state *state,
         fmode_t fmode, const struct nfs_lock_context *l_ctx,
         nfs4_stateid *dst, const struct cred **cred)
 {
     int ret;
 
     if (!nfs4_valid_open_stateid(state))
         return -EIO;
     if (cred != NULL)
         *cred = NULL;
     ret = nfs4_copy_lock_stateid(dst, state, l_ctx);
     if (ret == -EIO)
         /* A lost lock - don't even consider delegations */
         goto out;
     /* returns true if delegation stateid found and copied */
     if (nfs4_copy_delegation_stateid(state->inode, fmode, dst, cred)) {
         ret = 0;
         goto out;
     }
     if (ret != -ENOENT)
         /* nfs4_copy_delegation_stateid() didn't over-write
          * dst, so it still has the lock stateid which we now
          * choose to use.
          */
         goto out;
     ret = nfs4_copy_open_stateid(dst, state) ? 0 : -EAGAIN;
 out:
     if (nfs_server_capable(state->inode, NFS_CAP_STATEID_NFSV41))
         dst->seqid = 0;
     return ret;
 }
 
 struct nfs_seqid *nfs_alloc_seqid(struct nfs_seqid_counter *counter, gfp_t gfp_mask)
 {
     struct nfs_seqid *new;
 
     new = kmalloc(sizeof(*new), gfp_mask);
     if (new == NULL)
         return ERR_PTR(-ENOMEM);
     new->sequence = counter;
     INIT_LIST_HEAD(&new->list);
     new->task = NULL;
     return new;
 }
 
 void nfs_release_seqid(struct nfs_seqid *seqid)
 {
     struct nfs_seqid_counter *sequence;
 
     if (seqid == NULL || list_empty(&seqid->list))
         return;
     sequence = seqid->sequence;
     spin_lock(&sequence->lock);
     list_del_init(&seqid->list);
     if (!list_empty(&sequence->list)) {
         struct nfs_seqid *next;
 
         next = list_first_entry(&sequence->list,
                 struct nfs_seqid, list);
         rpc_wake_up_queued_task(&sequence->wait, next->task);
     }
     spin_unlock(&sequence->lock);
 }
 
 void nfs_free_seqid(struct nfs_seqid *seqid)
 {
     nfs_release_seqid(seqid);
     kfree(seqid);
 }
 
 /*
  * Increment the seqid if the OPEN/OPEN_DOWNGRADE/CLOSE succeeded, or
  * failed with a seqid incrementing error -
  * see comments nfs4.h:seqid_mutating_error()
  */
 static void nfs_increment_seqid(int status, struct nfs_seqid *seqid)
 {
     switch (status) {
         case 0:
             break;
         case -NFS4ERR_BAD_SEQID:
             if (seqid->sequence->flags & NFS_SEQID_CONFIRMED)
                 return;
             pr_warn_ratelimited("NFS: v4 server returned a bad"
                     " sequence-id error on an"
                     " unconfirmed sequence %p!\n",
                     seqid->sequence);
             return;
         case -NFS4ERR_STALE_CLIENTID:
         case -NFS4ERR_STALE_STATEID:
         case -NFS4ERR_BAD_STATEID:
         case -NFS4ERR_BADXDR:
         case -NFS4ERR_RESOURCE:
         case -NFS4ERR_NOFILEHANDLE:
         case -NFS4ERR_MOVED:
             /* Non-seqid mutating errors */
             return;
     }
     /*
      * Note: no locking needed as we are guaranteed to be first
      * on the sequence list
      */
     seqid->sequence->counter++;
 }
 
 void nfs_increment_open_seqid(int status, struct nfs_seqid *seqid)
 {
     struct nfs4_state_owner *sp;
 
     if (seqid == NULL)
         return;
 
     sp = container_of(seqid->sequence, struct nfs4_state_owner, so_seqid);
     if (status == -NFS4ERR_BAD_SEQID)
         nfs4_reset_state_owner(sp);
     if (!nfs4_has_session(sp->so_server->nfs_client))
         nfs_increment_seqid(status, seqid);
 }
 
 /*
  * Increment the seqid if the LOCK/LOCKU succeeded, or
  * failed with a seqid incrementing error -
  * see comments nfs4.h:seqid_mutating_error()
  */
 void nfs_increment_lock_seqid(int status, struct nfs_seqid *seqid)
 {
     if (seqid != NULL)
         nfs_increment_seqid(status, seqid);
 }
 
 int nfs_wait_on_sequence(struct nfs_seqid *seqid, struct rpc_task *task)
 {
     struct nfs_seqid_counter *sequence;
     int status = 0;
 
     if (seqid == NULL)
         goto out;
     sequence = seqid->sequence;
     spin_lock(&sequence->lock);
     seqid->task = task;
     if (list_empty(&seqid->list))
         list_add_tail(&seqid->list, &sequence->list);
     if (list_first_entry(&sequence->list, struct nfs_seqid, list) == seqid)
         goto unlock;
     rpc_sleep_on(&sequence->wait, task, NULL);
     status = -EAGAIN;
 unlock:
     spin_unlock(&sequence->lock);
 out:
     return status;
 }
 
 static int nfs4_run_state_manager(void *);
 
 static void nfs4_clear_state_manager_bit(struct nfs_client *clp)
 {
     clear_and_wake_up_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state);
     rpc_wake_up(&clp->cl_rpcwaitq);
 }
 
 /*
  * Schedule the nfs_client asynchronous state management routine
  */
 void nfs4_schedule_state_manager(struct nfs_client *clp)
 {
     struct task_struct *task;
     char buf[INET6_ADDRSTRLEN + sizeof("-manager") + 1];
     struct rpc_clnt *cl = clp->cl_rpcclient;
 
     while (cl != cl->cl_parent)
         cl = cl->cl_parent;
 
     set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state);
     if (test_and_set_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state) != 0) {
         wake_up_var(&clp->cl_state);
         return;
     }
     set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state);
     __module_get(THIS_MODULE);
     refcount_inc(&clp->cl_count);
 
     /* The rcu_read_lock() is not strictly necessary, as the state
      * manager is the only thread that ever changes the rpc_xprt
      * after it's initialized.  At this point, we're single threaded. */
     rcu_read_lock();
     snprintf(buf, sizeof(buf), "%s-manager",
             rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR));
     rcu_read_unlock();
     task = kthread_run(nfs4_run_state_manager, clp, "%s", buf);
     if (IS_ERR(task)) {
         printk(KERN_ERR "%s: kthread_run: %ld\n",
             __func__, PTR_ERR(task));
         nfs4_clear_state_manager_bit(clp);
         clear_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state);
         nfs_put_client(clp);
         module_put(THIS_MODULE);
     }
 }
 
 /*
  * Schedule a lease recovery attempt
  */
 void nfs4_schedule_lease_recovery(struct nfs_client *clp)
 {
     if (!clp)
         return;
     if (!test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state))
         set_bit(NFS4CLNT_CHECK_LEASE, &clp->cl_state);
     dprintk("%s: scheduling lease recovery for server %s\n", __func__,
             clp->cl_hostname);
     nfs4_schedule_state_manager(clp);
 }
 EXPORT_SYMBOL_GPL(nfs4_schedule_lease_recovery);
 
 /**
  * nfs4_schedule_migration_recovery - trigger migration recovery
  *
  * @server: FSID that is migrating
  *
  * Returns zero if recovery has started, otherwise a negative NFS4ERR
  * value is returned.
  */
 int nfs4_schedule_migration_recovery(const struct nfs_server *server)
 {
     struct nfs_client *clp = server->nfs_client;
 
     if (server->fh_expire_type != NFS4_FH_PERSISTENT) {
         pr_err("NFS: volatile file handles not supported (server %s)\n",
                 clp->cl_hostname);
         return -NFS4ERR_IO;
     }
 
     if (test_bit(NFS_MIG_FAILED, &server->mig_status))
         return -NFS4ERR_IO;
 
     dprintk("%s: scheduling migration recovery for (%llx:%llx) on %s\n",
             __func__,
             (unsigned long long)server->fsid.major,
             (unsigned long long)server->fsid.minor,
             clp->cl_hostname);
 
     set_bit(NFS_MIG_IN_TRANSITION,
             &((struct nfs_server *)server)->mig_status);
     set_bit(NFS4CLNT_MOVED, &clp->cl_state);
 
     nfs4_schedule_state_manager(clp);
     return 0;
 }
 EXPORT_SYMBOL_GPL(nfs4_schedule_migration_recovery);
 
 /**
  * nfs4_schedule_lease_moved_recovery - start lease-moved recovery
  *
  * @clp: server to check for moved leases
  *
  */
 void nfs4_schedule_lease_moved_recovery(struct nfs_client *clp)
 {
     dprintk("%s: scheduling lease-moved recovery for client ID %llx on %s\n",
         __func__, clp->cl_clientid, clp->cl_hostname);
 
     set_bit(NFS4CLNT_LEASE_MOVED, &clp->cl_state);
     nfs4_schedule_state_manager(clp);
 }
 EXPORT_SYMBOL_GPL(nfs4_schedule_lease_moved_recovery);
 
 int nfs4_wait_clnt_recover(struct nfs_client *clp)
 {
     int res;
 
     might_sleep();
 
     refcount_inc(&clp->cl_count);
     res = wait_on_bit_action(&clp->cl_state, NFS4CLNT_MANAGER_RUNNING,
                  nfs_wait_bit_killable, TASK_KILLABLE);
     if (res)
         goto out;
     if (clp->cl_cons_state < 0)
         res = clp->cl_cons_state;
 out:
     nfs_put_client(clp);
     return res;
 }
 
 int nfs4_client_recover_expired_lease(struct nfs_client *clp)
 {
     unsigned int loop;
     int ret;
 
     for (loop = NFS4_MAX_LOOP_ON_RECOVER; loop != 0; loop--) {
         ret = nfs4_wait_clnt_recover(clp);
         if (ret != 0)
             break;
         if (!test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) &&
             !test_bit(NFS4CLNT_CHECK_LEASE,&clp->cl_state))
             break;
         nfs4_schedule_state_manager(clp);
         ret = -EIO;
     }
     return ret;
 }
 
 /*
  * nfs40_handle_cb_pathdown - return all delegations after NFS4ERR_CB_PATH_DOWN
  * @clp: client to process
  *
  * Set the NFS4CLNT_LEASE_EXPIRED state in order to force a
  * resend of the SETCLIENTID and hence re-establish the
  * callback channel. Then return all existing delegations.
  */
 static void nfs40_handle_cb_pathdown(struct nfs_client *clp)
 {
     set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
     nfs_expire_all_delegations(clp);
     dprintk("%s: handling CB_PATHDOWN recovery for server %s\n", __func__,
             clp->cl_hostname);
 }
 
 void nfs4_schedule_path_down_recovery(struct nfs_client *clp)
 {
     nfs40_handle_cb_pathdown(clp);
     nfs4_schedule_state_manager(clp);
 }
 
 static int nfs4_state_mark_reclaim_reboot(struct nfs_client *clp, struct nfs4_state *state)
 {
 
     if (!nfs4_valid_open_stateid(state))
         return 0;
     set_bit(NFS_STATE_RECLAIM_REBOOT, &state->flags);
     /* Don't recover state that expired before the reboot */
     if (test_bit(NFS_STATE_RECLAIM_NOGRACE, &state->flags)) {
         clear_bit(NFS_STATE_RECLAIM_REBOOT, &state->flags);
         return 0;
     }
     set_bit(NFS_OWNER_RECLAIM_REBOOT, &state->owner->so_flags);
     set_bit(NFS4CLNT_RECLAIM_REBOOT, &clp->cl_state);
     return 1;
 }
 
 int nfs4_state_mark_reclaim_nograce(struct nfs_client *clp, struct nfs4_state *state)
 {
     if (!nfs4_valid_open_stateid(state))
         return 0;
     set_bit(NFS_STATE_RECLAIM_NOGRACE, &state->flags);
     clear_bit(NFS_STATE_RECLAIM_REBOOT, &state->flags);
     set_bit(NFS_OWNER_RECLAIM_NOGRACE, &state->owner->so_flags);
     set_bit(NFS4CLNT_RECLAIM_NOGRACE, &clp->cl_state);
     return 1;
 }
 
 int nfs4_schedule_stateid_recovery(const struct nfs_server *server, struct nfs4_state *state)
 {
     struct nfs_client *clp = server->nfs_client;
 
     if (!nfs4_state_mark_reclaim_nograce(clp, state))
         return -EBADF;
     nfs_inode_find_delegation_state_and_recover(state->inode,
             &state->stateid);
     dprintk("%s: scheduling stateid recovery for server %s\n", __func__,
             clp->cl_hostname);
     nfs4_schedule_state_manager(clp);
     return 0;
 }
 EXPORT_SYMBOL_GPL(nfs4_schedule_stateid_recovery);
 
 static struct nfs4_lock_state *
 nfs_state_find_lock_state_by_stateid(struct nfs4_state *state,
         const nfs4_stateid *stateid)
 {
     struct nfs4_lock_state *pos;
 
     list_for_each_entry(pos, &state->lock_states, ls_locks) {
         if (!test_bit(NFS_LOCK_INITIALIZED, &pos->ls_flags))
             continue;
         if (nfs4_stateid_match_or_older(&pos->ls_stateid, stateid))
             return pos;
     }
     return NULL;
 }
 
 static bool nfs_state_lock_state_matches_stateid(struct nfs4_state *state,
         const nfs4_stateid *stateid)
 {
     bool found = false;
 
     if (test_bit(LK_STATE_IN_USE, &state->flags)) {
         spin_lock(&state->state_lock);
         if (nfs_state_find_lock_state_by_stateid(state, stateid))
             found = true;
         spin_unlock(&state->state_lock);
     }
     return found;
 }
 
 void nfs_inode_find_state_and_recover(struct inode *inode,
         const nfs4_stateid *stateid)
 {
     struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
     struct nfs_inode *nfsi = NFS_I(inode);
     struct nfs_open_context *ctx;
     struct nfs4_state *state;
     bool found = false;
 
     rcu_read_lock();
     list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
         state = ctx->state;
         if (state == NULL)
             continue;
         if (nfs4_stateid_match_or_older(&state->stateid, stateid) &&
             nfs4_state_mark_reclaim_nograce(clp, state)) {
             found = true;
             continue;
         }
         if (test_bit(NFS_OPEN_STATE, &state->flags) &&
             nfs4_stateid_match_or_older(&state->open_stateid, stateid) &&
             nfs4_state_mark_reclaim_nograce(clp, state)) {
             found = true;
             continue;
         }
         if (nfs_state_lock_state_matches_stateid(state, stateid) &&
             nfs4_state_mark_reclaim_nograce(clp, state))
             found = true;
     }
     rcu_read_unlock();
 
     nfs_inode_find_delegation_state_and_recover(inode, stateid);
     if (found)
         nfs4_schedule_state_manager(clp);
 }
 
 static void nfs4_state_mark_open_context_bad(struct nfs4_state *state, int err)
 {
     struct inode *inode = state->inode;
     struct nfs_inode *nfsi = NFS_I(inode);
     struct nfs_open_context *ctx;
 
     rcu_read_lock();
     list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
         if (ctx->state != state)
             continue;
         set_bit(NFS_CONTEXT_BAD, &ctx->flags);
         pr_warn("NFSv4: state recovery failed for open file %pd2, "
                 "error = %d\n", ctx->dentry, err);
     }
     rcu_read_unlock();
 }
 
 static void nfs4_state_mark_recovery_failed(struct nfs4_state *state, int error)
 {
     set_bit(NFS_STATE_RECOVERY_FAILED, &state->flags);
     nfs4_state_mark_open_context_bad(state, error);
 }
 
 
 static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_recovery_ops *ops)
 {
     struct inode *inode = state->inode;
     struct nfs_inode *nfsi = NFS_I(inode);
     struct file_lock *fl;
     struct nfs4_lock_state *lsp;
     int status = 0;
     struct file_lock_context *flctx = inode->i_flctx;
     struct list_head *list;
 
     if (flctx == NULL)
         return 0;
 
     list = &flctx->flc_posix;
 
     /* Guard against delegation returns and new lock/unlock calls */
     down_write(&nfsi->rwsem);
     spin_lock(&flctx->flc_lock);
 restart:
     list_for_each_entry(fl, list, fl_list) {
         if (nfs_file_open_context(fl->fl_file)->state != state)
             continue;
         spin_unlock(&flctx->flc_lock);
         status = ops->recover_lock(state, fl);
         switch (status) {
         case 0:
             break;
         case -ETIMEDOUT:
         case -ESTALE:
         case -NFS4ERR_ADMIN_REVOKED:
         case -NFS4ERR_STALE_STATEID:
         case -NFS4ERR_BAD_STATEID:
         case -NFS4ERR_EXPIRED:
         case -NFS4ERR_NO_GRACE:
         case -NFS4ERR_STALE_CLIENTID:
         case -NFS4ERR_BADSESSION:
         case -NFS4ERR_BADSLOT:
         case -NFS4ERR_BAD_HIGH_SLOT:
         case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
             goto out;
         default:
             pr_err("NFS: %s: unhandled error %d\n",
                     __func__, status);
             fallthrough;
         case -ENOMEM:
         case -NFS4ERR_DENIED:
         case -NFS4ERR_RECLAIM_BAD:
         case -NFS4ERR_RECLAIM_CONFLICT:
             lsp = fl->fl_u.nfs4_fl.owner;
             if (lsp)
                 set_bit(NFS_LOCK_LOST, &lsp->ls_flags);
             status = 0;
         }
         spin_lock(&flctx->flc_lock);
     }
     if (list == &flctx->flc_posix) {
         list = &flctx->flc_flock;
         goto restart;
     }
     spin_unlock(&flctx->flc_lock);
 out:
     up_write(&nfsi->rwsem);
     return status;
 }
 
 #ifdef CONFIG_NFS_V4_2
 static void nfs42_complete_copies(struct nfs4_state_owner *sp, struct nfs4_state *state)
 {
     struct nfs4_copy_state *copy;
 
     if (!test_bit(NFS_CLNT_DST_SSC_COPY_STATE, &state->flags) &&
         !test_bit(NFS_CLNT_SRC_SSC_COPY_STATE, &state->flags))
         return;
 
     spin_lock(&sp->so_server->nfs_client->cl_lock);
     list_for_each_entry(copy, &sp->so_server->ss_copies, copies) {
         if ((test_bit(NFS_CLNT_DST_SSC_COPY_STATE, &state->flags) &&
                 !nfs4_stateid_match_other(&state->stateid,
                 &copy->parent_dst_state->stateid)))
                 continue;
         copy->flags = 1;
         if (test_and_clear_bit(NFS_CLNT_DST_SSC_COPY_STATE,
                 &state->flags)) {
             clear_bit(NFS_CLNT_SRC_SSC_COPY_STATE, &state->flags);
             complete(&copy->completion);
         }
     }
     list_for_each_entry(copy, &sp->so_server->ss_copies, src_copies) {
         if ((test_bit(NFS_CLNT_SRC_SSC_COPY_STATE, &state->flags) &&
                 !nfs4_stateid_match_other(&state->stateid,
                 &copy->parent_src_state->stateid)))
                 continue;
         copy->flags = 1;
         if (test_and_clear_bit(NFS_CLNT_DST_SSC_COPY_STATE,
                 &state->flags))
             complete(&copy->completion);
     }
     spin_unlock(&sp->so_server->nfs_client->cl_lock);
 }
 #else /* !CONFIG_NFS_V4_2 */
 static inline void nfs42_complete_copies(struct nfs4_state_owner *sp,
                      struct nfs4_state *state)
 {
 }
 #endif /* CONFIG_NFS_V4_2 */
 
 static int __nfs4_reclaim_open_state(struct nfs4_state_owner *sp, struct nfs4_state *state,
                      const struct nfs4_state_recovery_ops *ops,
                      int *lost_locks)
 {
     struct nfs4_lock_state *lock;
     int status;
 
     status = ops->recover_open(sp, state);
     if (status < 0)
         return status;
 
     status = nfs4_reclaim_locks(state, ops);
     if (status < 0)
         return status;
 
     if (!test_bit(NFS_DELEGATED_STATE, &state->flags)) {
         spin_lock(&state->state_lock);
         list_for_each_entry(lock, &state->lock_states, ls_locks) {
             trace_nfs4_state_lock_reclaim(state, lock);
             if (!test_bit(NFS_LOCK_INITIALIZED, &lock->ls_flags))
                 *lost_locks += 1;
         }
         spin_unlock(&state->state_lock);
     }
 
     nfs42_complete_copies(sp, state);
     clear_bit(NFS_STATE_RECLAIM_NOGRACE, &state->flags);
     return status;
 }
 
 static int nfs4_reclaim_open_state(struct nfs4_state_owner *sp,
                    const struct nfs4_state_recovery_ops *ops,
                    int *lost_locks)
 {
     struct nfs4_state *state;
     unsigned int loop = 0;
     int status = 0;
 #ifdef CONFIG_NFS_V4_2
     bool found_ssc_copy_state = false;
 #endif /* CONFIG_NFS_V4_2 */
 
     /* Note: we rely on the sp->so_states list being ordered 
      * so that we always reclaim open(O_RDWR) and/or open(O_WRITE)
      * states first.
      * This is needed to ensure that the server won't give us any
      * read delegations that we have to return if, say, we are
      * recovering after a network partition or a reboot from a
      * server that doesn't support a grace period.
      */
     spin_lock(&sp->so_lock);
     raw_write_seqcount_begin(&sp->so_reclaim_seqcount);
 restart:
     list_for_each_entry(state, &sp->so_states, open_states) {
         if (!test_and_clear_bit(ops->state_flag_bit, &state->flags))
             continue;
         if (!nfs4_valid_open_stateid(state))
             continue;
         if (state->state == 0)
             continue;
 #ifdef CONFIG_NFS_V4_2
         if (test_bit(NFS_SRV_SSC_COPY_STATE, &state->flags)) {
             nfs4_state_mark_recovery_failed(state, -EIO);
             found_ssc_copy_state = true;
             continue;
         }
 #endif /* CONFIG_NFS_V4_2 */
         refcount_inc(&state->count);
         spin_unlock(&sp->so_lock);
         status = __nfs4_reclaim_open_state(sp, state, ops, lost_locks);
 
         switch (status) {
         default:
             if (status >= 0) {
                 loop = 0;
                 break;
             }
             printk(KERN_ERR "NFS: %s: unhandled error %d\n", __func__, status);
             fallthrough;
         case -ENOENT:
         case -ENOMEM:
         case -EACCES:
         case -EROFS:
         case -EIO:
         case -ESTALE:
             /* Open state on this file cannot be recovered */
             nfs4_state_mark_recovery_failed(state, status);
             break;
         case -EAGAIN:
             ssleep(1);
             if (loop++ < 10) {
                 set_bit(ops->state_flag_bit, &state->flags);
                 break;
             }
             fallthrough;
         case -NFS4ERR_ADMIN_REVOKED:
         case -NFS4ERR_STALE_STATEID:
         case -NFS4ERR_OLD_STATEID:
         case -NFS4ERR_BAD_STATEID:
         case -NFS4ERR_RECLAIM_BAD:
         case -NFS4ERR_RECLAIM_CONFLICT:
             nfs4_state_mark_reclaim_nograce(sp->so_server->nfs_client, state);
             break;
         case -NFS4ERR_EXPIRED:
         case -NFS4ERR_NO_GRACE:
             nfs4_state_mark_reclaim_nograce(sp->so_server->nfs_client, state);
             fallthrough;
         case -NFS4ERR_STALE_CLIENTID:
         case -NFS4ERR_BADSESSION:
         case -NFS4ERR_BADSLOT:
         case -NFS4ERR_BAD_HIGH_SLOT:
         case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
         case -ETIMEDOUT:
             goto out_err;
         }
         nfs4_put_open_state(state);
         spin_lock(&sp->so_lock);
         goto restart;
     }
     raw_write_seqcount_end(&sp->so_reclaim_seqcount);
     spin_unlock(&sp->so_lock);
 #ifdef CONFIG_NFS_V4_2
     if (found_ssc_copy_state)
         return -EIO;
 #endif /* CONFIG_NFS_V4_2 */
     return 0;
 out_err:
     nfs4_put_open_state(state);
     spin_lock(&sp->so_lock);
     raw_write_seqcount_end(&sp->so_reclaim_seqcount);
     spin_unlock(&sp->so_lock);
     return status;
 }
 
 static void nfs4_clear_open_state(struct nfs4_state *state)
 {
     struct nfs4_lock_state *lock;
 
     clear_bit(NFS_DELEGATED_STATE, &state->flags);
     clear_bit(NFS_O_RDONLY_STATE, &state->flags);
     clear_bit(NFS_O_WRONLY_STATE, &state->flags);
     clear_bit(NFS_O_RDWR_STATE, &state->flags);
     spin_lock(&state->state_lock);
     list_for_each_entry(lock, &state->lock_states, ls_locks) {
         lock->ls_seqid.flags = 0;
         clear_bit(NFS_LOCK_INITIALIZED, &lock->ls_flags);
     }
     spin_unlock(&state->state_lock);
 }
 
 static void nfs4_reset_seqids(struct nfs_server *server,
     int (*mark_reclaim)(struct nfs_client *clp, struct nfs4_state *state))
 {
     struct nfs_client *clp = server->nfs_client;
     struct nfs4_state_owner *sp;
     struct rb_node *pos;
     struct nfs4_state *state;
 
     spin_lock(&clp->cl_lock);
     for (pos = rb_first(&server->state_owners);
          pos != NULL;
          pos = rb_next(pos)) {
         sp = rb_entry(pos, struct nfs4_state_owner, so_server_node);
         sp->so_seqid.flags = 0;
         spin_lock(&sp->so_lock);
         list_for_each_entry(state, &sp->so_states, open_states) {
             if (mark_reclaim(clp, state))
                 nfs4_clear_open_state(state);
         }
         spin_unlock(&sp->so_lock);
     }
     spin_unlock(&clp->cl_lock);
 }
 
 static void nfs4_state_mark_reclaim_helper(struct nfs_client *clp,
     int (*mark_reclaim)(struct nfs_client *clp, struct nfs4_state *state))
 {
     struct nfs_server *server;
 
     rcu_read_lock();
     list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
         nfs4_reset_seqids(server, mark_reclaim);
     rcu_read_unlock();
 }
 
 static void nfs4_state_start_reclaim_reboot(struct nfs_client *clp)
 {
     /* Mark all delegations for reclaim */
     nfs_delegation_mark_reclaim(clp);
     nfs4_state_mark_reclaim_helper(clp, nfs4_state_mark_reclaim_reboot);
 }
 
 static int nfs4_reclaim_complete(struct nfs_client *clp,
                  const struct nfs4_state_recovery_ops *ops,
                  const struct cred *cred)
 {
     /* Notify the server we're done reclaiming our state */
     if (ops->reclaim_complete)
         return ops->reclaim_complete(clp, cred);
     return 0;
 }
 
 static void nfs4_clear_reclaim_server(struct nfs_server *server)
 {
     struct nfs_client *clp = server->nfs_client;
     struct nfs4_state_owner *sp;
     struct rb_node *pos;
     struct nfs4_state *state;
 
     spin_lock(&clp->cl_lock);
     for (pos = rb_first(&server->state_owners);
          pos != NULL;
          pos = rb_next(pos)) {
         sp = rb_entry(pos, struct nfs4_state_owner, so_server_node);
         spin_lock(&sp->so_lock);
         list_for_each_entry(state, &sp->so_states, open_states) {
             if (!test_and_clear_bit(NFS_STATE_RECLAIM_REBOOT,
                         &state->flags))
                 continue;
             nfs4_state_mark_reclaim_nograce(clp, state);
         }
         spin_unlock(&sp->so_lock);
     }
     spin_unlock(&clp->cl_lock);
 }
 
 static int nfs4_state_clear_reclaim_reboot(struct nfs_client *clp)
 {
     struct nfs_server *server;
 
     if (!test_and_clear_bit(NFS4CLNT_RECLAIM_REBOOT, &clp->cl_state))
         return 0;
 
     rcu_read_lock();
     list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
         nfs4_clear_reclaim_server(server);
     rcu_read_unlock();
 
     nfs_delegation_reap_unclaimed(clp);
     return 1;
 }
 
 static void nfs4_state_end_reclaim_reboot(struct nfs_client *clp)
 {
     const struct nfs4_state_recovery_ops *ops;
     const struct cred *cred;
     int err;
 
     if (!nfs4_state_clear_reclaim_reboot(clp))
         return;
     ops = clp->cl_mvops->reboot_recovery_ops;
     cred = nfs4_get_clid_cred(clp);
     err = nfs4_reclaim_complete(clp, ops, cred);
     put_cred(cred);
     if (err == -NFS4ERR_CONN_NOT_BOUND_TO_SESSION)
         set_bit(NFS4CLNT_RECLAIM_REBOOT, &clp->cl_state);
 }
 
 static void nfs4_state_start_reclaim_nograce(struct nfs_client *clp)
 {
     nfs_mark_test_expired_all_delegations(clp);
     nfs4_state_mark_reclaim_helper(clp, nfs4_state_mark_reclaim_nograce);
 }
 
 static int nfs4_recovery_handle_error(struct nfs_client *clp, int error)
 {
     switch (error) {
     case 0:
         break;
     case -NFS4ERR_CB_PATH_DOWN:
         nfs40_handle_cb_pathdown(clp);
         break;
     case -NFS4ERR_NO_GRACE:
         nfs4_state_end_reclaim_reboot(clp);
         break;
     case -NFS4ERR_STALE_CLIENTID:
         set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
         nfs4_state_start_reclaim_reboot(clp);
         break;
     case -NFS4ERR_EXPIRED:
         set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
         nfs4_state_start_reclaim_nograce(clp);
         break;
     case -NFS4ERR_BADSESSION:
     case -NFS4ERR_BADSLOT:
     case -NFS4ERR_BAD_HIGH_SLOT:
     case -NFS4ERR_DEADSESSION:
     case -NFS4ERR_SEQ_FALSE_RETRY:
     case -NFS4ERR_SEQ_MISORDERED:
         set_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state);
         /* Zero session reset errors */
         break;
     case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
         set_bit(NFS4CLNT_BIND_CONN_TO_SESSION, &clp->cl_state);
         break;
     default:
         dprintk("%s: failed to handle error %d for server %s\n",
                 __func__, error, clp->cl_hostname);
         return error;
     }
     dprintk("%s: handled error %d for server %s\n", __func__, error,
             clp->cl_hostname);
     return 0;
 }
 
 static int nfs4_do_reclaim(struct nfs_client *clp, const struct nfs4_state_recovery_ops *ops)
 {
     struct nfs4_state_owner *sp;
     struct nfs_server *server;
     struct rb_node *pos;
     LIST_HEAD(freeme);
     int status = 0;
     int lost_locks = 0;
 
 restart:
     rcu_read_lock();
     list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
         nfs4_purge_state_owners(server, &freeme);
         spin_lock(&clp->cl_lock);
         for (pos = rb_first(&server->state_owners);
              pos != NULL;
              pos = rb_next(pos)) {
             sp = rb_entry(pos,
                 struct nfs4_state_owner, so_server_node);
             if (!test_and_clear_bit(ops->owner_flag_bit,
                             &sp->so_flags))
                 continue;
             if (!atomic_inc_not_zero(&sp->so_count))
                 continue;
             spin_unlock(&clp->cl_lock);
             rcu_read_unlock();
 
             status = nfs4_reclaim_open_state(sp, ops, &lost_locks);
             if (status < 0) {
                 if (lost_locks)
                     pr_warn("NFS: %s: lost %d locks\n",
                         clp->cl_hostname, lost_locks);
                 set_bit(ops->owner_flag_bit, &sp->so_flags);
                 nfs4_put_state_owner(sp);
                 status = nfs4_recovery_handle_error(clp, status);
                 return (status != 0) ? status : -EAGAIN;
             }
 
             nfs4_put_state_owner(sp);
             goto restart;
         }
         spin_unlock(&clp->cl_lock);
     }
     rcu_read_unlock();
     nfs4_free_state_owners(&freeme);
     if (lost_locks)
         pr_warn("NFS: %s: lost %d locks\n",
             clp->cl_hostname, lost_locks);
     return 0;
 }
 
 static int nfs4_check_lease(struct nfs_client *clp)
 {
     const struct cred *cred;
     const struct nfs4_state_maintenance_ops *ops =
         clp->cl_mvops->state_renewal_ops;
     int status;
 
     /* Is the client already known to have an expired lease? */
     if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state))
         return 0;
     cred = ops->get_state_renewal_cred(clp);
     if (cred == NULL) {
         cred = nfs4_get_clid_cred(clp);
         status = -ENOKEY;
         if (cred == NULL)
             goto out;
     }
     status = ops->renew_lease(clp, cred);
     put_cred(cred);
     if (status == -ETIMEDOUT) {
         set_bit(NFS4CLNT_CHECK_LEASE, &clp->cl_state);
         return 0;
     }
 out:
     return nfs4_recovery_handle_error(clp, status);
 }
 
 /* Set NFS4CLNT_LEASE_EXPIRED and reclaim reboot state for all v4.0 errors
  * and for recoverable errors on EXCHANGE_ID for v4.1
  */
 static int nfs4_handle_reclaim_lease_error(struct nfs_client *clp, int status)
 {
     switch (status) {
     case -NFS4ERR_SEQ_MISORDERED:
         if (test_and_set_bit(NFS4CLNT_PURGE_STATE, &clp->cl_state))
             return -ESERVERFAULT;
         /* Lease confirmation error: retry after purging the lease */
         ssleep(1);
         clear_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
         break;
     case -NFS4ERR_STALE_CLIENTID:
         clear_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
         nfs4_state_start_reclaim_reboot(clp);
         break;
     case -NFS4ERR_CLID_INUSE:
         pr_err("NFS: Server %s reports our clientid is in use\n",
             clp->cl_hostname);
         nfs_mark_client_ready(clp, -EPERM);
         clear_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
         return -EPERM;
     case -EACCES:
     case -NFS4ERR_DELAY:
     case -EAGAIN:
         ssleep(1);
         break;
 
     case -NFS4ERR_MINOR_VERS_MISMATCH:
         if (clp->cl_cons_state == NFS_CS_SESSION_INITING)
             nfs_mark_client_ready(clp, -EPROTONOSUPPORT);
         dprintk("%s: exit with error %d for server %s\n",
                 __func__, -EPROTONOSUPPORT, clp->cl_hostname);
         return -EPROTONOSUPPORT;
     case -ENOSPC:
         if (clp->cl_cons_state == NFS_CS_SESSION_INITING)
             nfs_mark_client_ready(clp, -EIO);
         return -EIO;
     case -NFS4ERR_NOT_SAME: /* FixMe: implement recovery
                  * in nfs4_exchange_id */
     default:
         dprintk("%s: exit with error %d for server %s\n", __func__,
                 status, clp->cl_hostname);
         return status;
     }
     set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
     dprintk("%s: handled error %d for server %s\n", __func__, status,
             clp->cl_hostname);
     return 0;
 }
 
 static int nfs4_establish_lease(struct nfs_client *clp)
 {
     const struct cred *cred;
     const struct nfs4_state_recovery_ops *ops =
         clp->cl_mvops->reboot_recovery_ops;
     int status;
 
     status = nfs4_begin_drain_session(clp);
     if (status != 0)
         return status;
     cred = nfs4_get_clid_cred(clp);
     if (cred == NULL)
         return -ENOENT;
     status = ops->establish_clid(clp, cred);
     put_cred(cred);
     if (status != 0)
         return status;
     pnfs_destroy_all_layouts(clp);
     return 0;
 }
 
 /*
  * Returns zero or a negative errno.  NFS4ERR values are converted
  * to local errno values.
  */
 static int nfs4_reclaim_lease(struct nfs_client *clp)
 {
     int status;
 
     status = nfs4_establish_lease(clp);
     if (status < 0)
         return nfs4_handle_reclaim_lease_error(clp, status);
     if (test_and_clear_bit(NFS4CLNT_SERVER_SCOPE_MISMATCH, &clp->cl_state))
         nfs4_state_start_reclaim_nograce(clp);
     if (!test_bit(NFS4CLNT_RECLAIM_NOGRACE, &clp->cl_state))
         set_bit(NFS4CLNT_RECLAIM_REBOOT, &clp->cl_state);
     clear_bit(NFS4CLNT_CHECK_LEASE, &clp->cl_state);
     clear_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
     return 0;
 }
 
 static int nfs4_purge_lease(struct nfs_client *clp)
 {
     int status;
 
     status = nfs4_establish_lease(clp);
     if (status < 0)
         return nfs4_handle_reclaim_lease_error(clp, status);
     clear_bit(NFS4CLNT_PURGE_STATE, &clp->cl_state);
     set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
     nfs4_state_start_reclaim_nograce(clp);
     return 0;
 }
 
 /*
  * Try remote migration of one FSID from a source server to a
  * destination server.  The source server provides a list of
  * potential destinations.
  *
  * Returns zero or a negative NFS4ERR status code.
  */
 static int nfs4_try_migration(struct nfs_server *server, const struct cred *cred)
 {
     struct nfs_client *clp = server->nfs_client;
     struct nfs4_fs_locations *locations = NULL;
     struct inode *inode;
     struct page *page;
     int status, result;
 
     dprintk("--> %s: FSID %llx:%llx on \"%s\"\n", __func__,
             (unsigned long long)server->fsid.major,
             (unsigned long long)server->fsid.minor,
             clp->cl_hostname);
 
     result = 0;
     page = alloc_page(GFP_KERNEL);
     locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
     if (page == NULL || locations == NULL) {
         dprintk("<-- %s: no memory\n", __func__);
         goto out;
     }
     locations->fattr = nfs_alloc_fattr();
     if (locations->fattr == NULL) {
         dprintk("<-- %s: no memory\n", __func__);
         goto out;
     }
 
     inode = d_inode(server->super->s_root);
     result = nfs4_proc_get_locations(server, NFS_FH(inode), locations,
                      page, cred);
     if (result) {
         dprintk("<-- %s: failed to retrieve fs_locations: %d\n",
             __func__, result);
         goto out;
     }
 
     result = -NFS4ERR_NXIO;
     if (!locations->nlocations)
         goto out;
 
     if (!(locations->fattr->valid & NFS_ATTR_FATTR_V4_LOCATIONS)) {
         dprintk("<-- %s: No fs_locations data, migration skipped\n",
             __func__);
         goto out;
     }
 
     status = nfs4_begin_drain_session(clp);
     if (status != 0) {
         result = status;
         goto out;
     }
 
     status = nfs4_replace_transport(server, locations);
     if (status != 0) {
         dprintk("<-- %s: failed to replace transport: %d\n",
             __func__, status);
         goto out;
     }
 
     result = 0;
     dprintk("<-- %s: migration succeeded\n", __func__);
 
 out:
     if (page != NULL)
         __free_page(page);
     if (locations != NULL)
         kfree(locations->fattr);
     kfree(locations);
     if (result) {
         pr_err("NFS: migration recovery failed (server %s)\n",
                 clp->cl_hostname);
         set_bit(NFS_MIG_FAILED, &server->mig_status);
     }
     return result;
 }
 
 /*
  * Returns zero or a negative NFS4ERR status code.
  */
 static int nfs4_handle_migration(struct nfs_client *clp)
 {
     const struct nfs4_state_maintenance_ops *ops =
                 clp->cl_mvops->state_renewal_ops;
     struct nfs_server *server;
     const struct cred *cred;
 
     dprintk("%s: migration reported on \"%s\"\n", __func__,
             clp->cl_hostname);
 
     cred = ops->get_state_renewal_cred(clp);
     if (cred == NULL)
         return -NFS4ERR_NOENT;
 
     clp->cl_mig_gen++;
 restart:
     rcu_read_lock();
     list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
         int status;
 
         if (server->mig_gen == clp->cl_mig_gen)
             continue;
         server->mig_gen = clp->cl_mig_gen;
 
         if (!test_and_clear_bit(NFS_MIG_IN_TRANSITION,
                         &server->mig_status))
             continue;
 
         rcu_read_unlock();
         status = nfs4_try_migration(server, cred);
         if (status < 0) {
             put_cred(cred);
             return status;
         }
         goto restart;
     }
     rcu_read_unlock();
     put_cred(cred);
     return 0;
 }
 
 /*
  * Test each nfs_server on the clp's cl_superblocks list to see
  * if it's moved to another server.  Stop when the server no longer
  * returns NFS4ERR_LEASE_MOVED.
  */
 static int nfs4_handle_lease_moved(struct nfs_client *clp)
 {
     const struct nfs4_state_maintenance_ops *ops =
                 clp->cl_mvops->state_renewal_ops;
     struct nfs_server *server;
     const struct cred *cred;
 
     dprintk("%s: lease moved reported on \"%s\"\n", __func__,
             clp->cl_hostname);
 
     cred = ops->get_state_renewal_cred(clp);
     if (cred == NULL)
         return -NFS4ERR_NOENT;
 
     clp->cl_mig_gen++;
 restart:
     rcu_read_lock();
     list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
         struct inode *inode;
         int status;
 
         if (server->mig_gen == clp->cl_mig_gen)
             continue;
         server->mig_gen = clp->cl_mig_gen;
 
         rcu_read_unlock();
 
         inode = d_inode(server->super->s_root);
         status = nfs4_proc_fsid_present(inode, cred);
         if (status != -NFS4ERR_MOVED)
             goto restart;   /* wasn't this one */
         if (nfs4_try_migration(server, cred) == -NFS4ERR_LEASE_MOVED)
             goto restart;   /* there are more */
         goto out;
     }
     rcu_read_unlock();
 
 out:
     put_cred(cred);
     return 0;
 }
 
 /**
  * nfs4_discover_server_trunking - Detect server IP address trunking
  *
  * @clp: nfs_client under test
  * @result: OUT: found nfs_client, or clp
  *
  * Returns zero or a negative errno.  If zero is returned,
  * an nfs_client pointer is planted in "result".
  *
  * Note: since we are invoked in process context, and
  * not from inside the state manager, we cannot use
  * nfs4_handle_reclaim_lease_error().
  */
 int nfs4_discover_server_trunking(struct nfs_client *clp,
                   struct nfs_client **result)
 {
     const struct nfs4_state_recovery_ops *ops =
                 clp->cl_mvops->reboot_recovery_ops;
     struct rpc_clnt *clnt;
     const struct cred *cred;
     int i, status;
 
     dprintk("NFS: %s: testing '%s'\n", __func__, clp->cl_hostname);
 
     clnt = clp->cl_rpcclient;
     i = 0;
 
     mutex_lock(&nfs_clid_init_mutex);
 again:
     status  = -ENOENT;
     cred = nfs4_get_clid_cred(clp);
     if (cred == NULL)
         goto out_unlock;
 
     status = ops->detect_trunking(clp, result, cred);
     put_cred(cred);
     switch (status) {
     case 0:
     case -EINTR:
     case -ERESTARTSYS:
         break;
     case -ETIMEDOUT:
         if (clnt->cl_softrtry)
             break;
         fallthrough;
     case -NFS4ERR_DELAY:
     case -EAGAIN:
         ssleep(1);
         fallthrough;
     case -NFS4ERR_STALE_CLIENTID:
         dprintk("NFS: %s after status %d, retrying\n",
             __func__, status);
         goto again;
     case -EACCES:
         if (i++ == 0) {
             nfs4_root_machine_cred(clp);
             goto again;
         }
         if (clnt->cl_auth->au_flavor == RPC_AUTH_UNIX)
             break;
         fallthrough;
     case -NFS4ERR_CLID_INUSE:
     case -NFS4ERR_WRONGSEC:
         /* No point in retrying if we already used RPC_AUTH_UNIX */
         if (clnt->cl_auth->au_flavor == RPC_AUTH_UNIX) {
             status = -EPERM;
             break;
         }
         clnt = rpc_clone_client_set_auth(clnt, RPC_AUTH_UNIX);
         if (IS_ERR(clnt)) {
             status = PTR_ERR(clnt);
             break;
         }
         /* Note: this is safe because we haven't yet marked the
          * client as ready, so we are the only user of
          * clp->cl_rpcclient
          */
         clnt = xchg(&clp->cl_rpcclient, clnt);
         rpc_shutdown_client(clnt);
         clnt = clp->cl_rpcclient;
         goto again;
 
     case -NFS4ERR_MINOR_VERS_MISMATCH:
         status = -EPROTONOSUPPORT;
         break;
 
     case -EKEYEXPIRED:
     case -NFS4ERR_NOT_SAME: /* FixMe: implement recovery
                  * in nfs4_exchange_id */
         status = -EKEYEXPIRED;
         break;
     default:
         pr_warn("NFS: %s unhandled error %d. Exiting with error EIO\n",
                 __func__, status);
         status = -EIO;
     }
 
 out_unlock:
     mutex_unlock(&nfs_clid_init_mutex);
     dprintk("NFS: %s: status = %d\n", __func__, status);
     return status;
 }
 
 #ifdef CONFIG_NFS_V4_1
 void nfs4_schedule_session_recovery(struct nfs4_session *session, int err)
 {
     struct nfs_client *clp = session->clp;
 
     switch (err) {
     default:
         set_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state);
         break;
     case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
         set_bit(NFS4CLNT_BIND_CONN_TO_SESSION, &clp->cl_state);
     }
     nfs4_schedule_state_manager(clp);
 }
 EXPORT_SYMBOL_GPL(nfs4_schedule_session_recovery);
 
 void nfs41_notify_server(struct nfs_client *clp)
 {
     /* Use CHECK_LEASE to ping the server with a SEQUENCE */
     set_bit(NFS4CLNT_CHECK_LEASE, &clp->cl_state);
     nfs4_schedule_state_manager(clp);
 }
 
 static void nfs4_reset_all_state(struct nfs_client *clp)
 {
     if (test_and_set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0) {
         set_bit(NFS4CLNT_PURGE_STATE, &clp->cl_state);
         clear_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
         nfs4_state_start_reclaim_nograce(clp);
         dprintk("%s: scheduling reset of all state for server %s!\n",
                 __func__, clp->cl_hostname);
         nfs4_schedule_state_manager(clp);
     }
 }
 
 static void nfs41_handle_server_reboot(struct nfs_client *clp)
 {
     if (test_and_set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0) {
         nfs4_state_start_reclaim_reboot(clp);
         dprintk("%s: server %s rebooted!\n", __func__,
                 clp->cl_hostname);
         nfs4_schedule_state_manager(clp);
     }
 }
 
 static void nfs41_handle_all_state_revoked(struct nfs_client *clp)
 {
     nfs4_reset_all_state(clp);
     dprintk("%s: state revoked on server %s\n", __func__, clp->cl_hostname);
 }
 
 static void nfs41_handle_some_state_revoked(struct nfs_client *clp)
 {
     nfs4_state_start_reclaim_nograce(clp);
     nfs4_schedule_state_manager(clp);
 
     dprintk("%s: state revoked on server %s\n", __func__, clp->cl_hostname);
 }
 
 static void nfs41_handle_recallable_state_revoked(struct nfs_client *clp)
 {
     /* FIXME: For now, we destroy all layouts. */
     pnfs_destroy_all_layouts(clp);
     nfs_test_expired_all_delegations(clp);
     dprintk("%s: Recallable state revoked on server %s!\n", __func__,
             clp->cl_hostname);
 }
 
 static void nfs41_handle_backchannel_fault(struct nfs_client *clp)
 {
     set_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state);
     nfs4_schedule_state_manager(clp);
 
     dprintk("%s: server %s declared a backchannel fault\n", __func__,
             clp->cl_hostname);
 }
 
 static void nfs41_handle_cb_path_down(struct nfs_client *clp)
 {
     if (test_and_set_bit(NFS4CLNT_BIND_CONN_TO_SESSION,
         &clp->cl_state) == 0)
         nfs4_schedule_state_manager(clp);
 }
 
 void nfs41_handle_sequence_flag_errors(struct nfs_client *clp, u32 flags,
         bool recovery)
 {
     if (!flags)
         return;
 
     dprintk("%s: \"%s\" (client ID %llx) flags=0x%08x\n",
         __func__, clp->cl_hostname, clp->cl_clientid, flags);
     /*
      * If we're called from the state manager thread, then assume we're
      * already handling the RECLAIM_NEEDED and/or STATE_REVOKED.
      * Those flags are expected to remain set until we're done
      * recovering (see RFC5661, section 18.46.3).
      */
     if (recovery)
         goto out_recovery;
 
     if (flags & SEQ4_STATUS_RESTART_RECLAIM_NEEDED)
         nfs41_handle_server_reboot(clp);
     if (flags & (SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED))
         nfs41_handle_all_state_revoked(clp);
     if (flags & (SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED |
                 SEQ4_STATUS_ADMIN_STATE_REVOKED))
         nfs41_handle_some_state_revoked(clp);
     if (flags & SEQ4_STATUS_LEASE_MOVED)
         nfs4_schedule_lease_moved_recovery(clp);
     if (flags & SEQ4_STATUS_RECALLABLE_STATE_REVOKED)
         nfs41_handle_recallable_state_revoked(clp);
 out_recovery:
     if (flags & SEQ4_STATUS_BACKCHANNEL_FAULT)
         nfs41_handle_backchannel_fault(clp);
     else if (flags & (SEQ4_STATUS_CB_PATH_DOWN |
                 SEQ4_STATUS_CB_PATH_DOWN_SESSION))
         nfs41_handle_cb_path_down(clp);
 }
 
 static int nfs4_reset_session(struct nfs_client *clp)
 {
     const struct cred *cred;
     int status;
 
     if (!nfs4_has_session(clp))
         return 0;
     status = nfs4_begin_drain_session(clp);
     if (status != 0)
         return status;
     cred = nfs4_get_clid_cred(clp);
     status = nfs4_proc_destroy_session(clp->cl_session, cred);
     switch (status) {
     case 0:
     case -NFS4ERR_BADSESSION:
     case -NFS4ERR_DEADSESSION:
         break;
     case -NFS4ERR_BACK_CHAN_BUSY:
     case -NFS4ERR_DELAY:
         set_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state);
         status = 0;
         ssleep(1);
         goto out;
     default:
         status = nfs4_recovery_handle_error(clp, status);
         goto out;
     }
 
     memset(clp->cl_session->sess_id.data, 0, NFS4_MAX_SESSIONID_LEN);
     status = nfs4_proc_create_session(clp, cred);
     if (status) {
         dprintk("%s: session reset failed with status %d for server %s!\n",
             __func__, status, clp->cl_hostname);
         status = nfs4_handle_reclaim_lease_error(clp, status);
         goto out;
     }
     nfs41_finish_session_reset(clp);
     dprintk("%s: session reset was successful for server %s!\n",
             __func__, clp->cl_hostname);
 out:
     put_cred(cred);
     return status;
 }
 
 static int nfs4_bind_conn_to_session(struct nfs_client *clp)
 {
     const struct cred *cred;
     int ret;
 
     if (!nfs4_has_session(clp))
         return 0;
     ret = nfs4_begin_drain_session(clp);
     if (ret != 0)
         return ret;
     cred = nfs4_get_clid_cred(clp);
     ret = nfs4_proc_bind_conn_to_session(clp, cred);
     put_cred(cred);
     clear_bit(NFS4CLNT_BIND_CONN_TO_SESSION, &clp->cl_state);
     switch (ret) {
     case 0:
         dprintk("%s: bind_conn_to_session was successful for server %s!\n",
             __func__, clp->cl_hostname);
         break;
     case -NFS4ERR_DELAY:
         ssleep(1);
         set_bit(NFS4CLNT_BIND_CONN_TO_SESSION, &clp->cl_state);
         break;
     default:
         return nfs4_recovery_handle_error(clp, ret);
     }
     return 0;
 }
 
 static void nfs4_layoutreturn_any_run(struct nfs_client *clp)
 {
     int iomode = 0;
 
     if (test_and_clear_bit(NFS4CLNT_RECALL_ANY_LAYOUT_READ, &clp->cl_state))
         iomode += IOMODE_READ;
     if (test_and_clear_bit(NFS4CLNT_RECALL_ANY_LAYOUT_RW, &clp->cl_state))
         iomode += IOMODE_RW;
     /* Note: IOMODE_READ + IOMODE_RW == IOMODE_ANY */
     if (iomode) {
         pnfs_layout_return_unused_byclid(clp, iomode);
         set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state);
     }
 }
 #else /* CONFIG_NFS_V4_1 */
 static int nfs4_reset_session(struct nfs_client *clp) { return 0; }
 
 static int nfs4_bind_conn_to_session(struct nfs_client *clp)
 {
     return 0;
 }
 
 static void nfs4_layoutreturn_any_run(struct nfs_client *clp)
 {
 }
 #endif /* CONFIG_NFS_V4_1 */
 
 static void nfs4_state_manager(struct nfs_client *clp)
 {
     unsigned int memflags;
     int status = 0;
     const char *section = "", *section_sep = "";
 
     /*
      * State recovery can deadlock if the direct reclaim code tries
      * start NFS writeback. So ensure memory allocations are all
      * GFP_NOFS.
      */
     memflags = memalloc_nofs_save();
 
     /* Ensure exclusive access to NFSv4 state */
     do {
         trace_nfs4_state_mgr(clp);
         clear_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state);
         if (test_bit(NFS4CLNT_PURGE_STATE, &clp->cl_state)) {
             section = "purge state";
             status = nfs4_purge_lease(clp);
             if (status < 0)
                 goto out_error;
             continue;
         }
 
         if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state)) {
             section = "lease expired";
             /* We're going to have to re-establish a clientid */
             status = nfs4_reclaim_lease(clp);
             if (status < 0)
                 goto out_error;
             continue;
         }
 
         /* Initialize or reset the session */
         if (test_and_clear_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state)) {
             section = "reset session";
             status = nfs4_reset_session(clp);
             if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state))
                 continue;
             if (status < 0)
                 goto out_error;
         }
 
         /* Send BIND_CONN_TO_SESSION */
         if (test_and_clear_bit(NFS4CLNT_BIND_CONN_TO_SESSION,
                 &clp->cl_state)) {
             section = "bind conn to session";
             status = nfs4_bind_conn_to_session(clp);
             if (status < 0)
                 goto out_error;
             continue;
         }
 
         if (test_and_clear_bit(NFS4CLNT_CHECK_LEASE, &clp->cl_state)) {
             section = "check lease";
             status = nfs4_check_lease(clp);
             if (status < 0)
                 goto out_error;
             continue;
         }
 
         if (test_and_clear_bit(NFS4CLNT_MOVED, &clp->cl_state)) {
             section = "migration";
             status = nfs4_handle_migration(clp);
             if (status < 0)
                 goto out_error;
         }
 
         if (test_and_clear_bit(NFS4CLNT_LEASE_MOVED, &clp->cl_state)) {
             section = "lease moved";
             status = nfs4_handle_lease_moved(clp);
             if (status < 0)
                 goto out_error;
         }
 
         /* First recover reboot state... */
         if (test_bit(NFS4CLNT_RECLAIM_REBOOT, &clp->cl_state)) {
             section = "reclaim reboot";
             status = nfs4_do_reclaim(clp,
                 clp->cl_mvops->reboot_recovery_ops);
             if (status == -EAGAIN)
                 continue;
             if (status < 0)
                 goto out_error;
             nfs4_state_end_reclaim_reboot(clp);
         }
 
         /* Detect expired delegations... */
         if (test_and_clear_bit(NFS4CLNT_DELEGATION_EXPIRED, &clp->cl_state)) {
             section = "detect expired delegations";
             nfs_reap_expired_delegations(clp);
             continue;
         }
 
         /* Now recover expired state... */
         if (test_bit(NFS4CLNT_RECLAIM_NOGRACE, &clp->cl_state)) {
             section = "reclaim nograce";
             status = nfs4_do_reclaim(clp,
                 clp->cl_mvops->nograce_recovery_ops);
             if (status == -EAGAIN)
                 continue;
             if (status < 0)
                 goto out_error;
             clear_bit(NFS4CLNT_RECLAIM_NOGRACE, &clp->cl_state);
         }
 
         memalloc_nofs_restore(memflags);
         nfs4_end_drain_session(clp);
         nfs4_clear_state_manager_bit(clp);
 
         if (!test_and_set_bit(NFS4CLNT_RECALL_RUNNING, &clp->cl_state)) {
             if (test_and_clear_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state)) {
                 nfs_client_return_marked_delegations(clp);
                 set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state);
             }
             nfs4_layoutreturn_any_run(clp);
             clear_bit(NFS4CLNT_RECALL_RUNNING, &clp->cl_state);
         }
 
         return;
 
     } while (refcount_read(&clp->cl_count) > 1 && !signalled());
     goto out_drain;
 
 out_error:
     if (strlen(section))
         section_sep = ": ";
     trace_nfs4_state_mgr_failed(clp, section, status);
     pr_warn_ratelimited("NFS: state manager%s%s failed on NFSv4 server %s"
             " with error %d\n", section_sep, section,
             clp->cl_hostname, -status);
     ssleep(1);
 out_drain:
     memalloc_nofs_restore(memflags);
     nfs4_end_drain_session(clp);
     nfs4_clear_state_manager_bit(clp);
 }
 
 static int nfs4_run_state_manager(void *ptr)
 {
     struct nfs_client *clp = ptr;
     struct rpc_clnt *cl = clp->cl_rpcclient;
 
     while (cl != cl->cl_parent)
         cl = cl->cl_parent;
 
     allow_signal(SIGKILL);
 again:
     set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state);
     nfs4_state_manager(clp);
     if (atomic_read(&cl->cl_swapper)) {
         wait_var_event_interruptible(&clp->cl_state,
                          test_bit(NFS4CLNT_RUN_MANAGER,
                               &clp->cl_state));
         if (atomic_read(&cl->cl_swapper) &&
             test_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state))
             goto again;
         /* Either no longer a swapper, or were signalled */
     }
     clear_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state);
 
     if (refcount_read(&clp->cl_count) > 1 && !signalled() &&
         test_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state) &&
         !test_and_set_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state))
         goto again;
 
     nfs_put_client(clp);
     module_put_and_kthread_exit(0);
     return 0;
 }