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![Benjamin Coddington](/assets/img/avatar_default.png)
After lockd is started, add a symlink for lockd's rpc_client under NFS' superblock sysfs. Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
297 lines
7.4 KiB
C
297 lines
7.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/fs/lockd/clntlock.c
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*
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* Lock handling for the client side NLM implementation
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*
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* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/time.h>
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#include <linux/nfs_fs.h>
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#include <linux/sunrpc/addr.h>
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#include <linux/sunrpc/svc.h>
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#include <linux/sunrpc/svc_xprt.h>
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#include <linux/lockd/lockd.h>
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#include <linux/kthread.h>
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#include "trace.h"
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#define NLMDBG_FACILITY NLMDBG_CLIENT
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/*
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* Local function prototypes
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*/
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static int reclaimer(void *ptr);
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/*
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* The following functions handle blocking and granting from the
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* client perspective.
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*/
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static LIST_HEAD(nlm_blocked);
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static DEFINE_SPINLOCK(nlm_blocked_lock);
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/**
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* nlmclnt_init - Set up per-NFS mount point lockd data structures
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* @nlm_init: pointer to arguments structure
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*
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* Returns pointer to an appropriate nlm_host struct,
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* or an ERR_PTR value.
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*/
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struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init)
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{
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struct nlm_host *host;
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u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4;
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int status;
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status = lockd_up(nlm_init->net, nlm_init->cred);
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if (status < 0)
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return ERR_PTR(status);
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host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen,
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nlm_init->protocol, nlm_version,
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nlm_init->hostname, nlm_init->noresvport,
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nlm_init->net, nlm_init->cred);
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if (host == NULL)
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goto out_nohost;
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if (host->h_rpcclnt == NULL && nlm_bind_host(host) == NULL)
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goto out_nobind;
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host->h_nlmclnt_ops = nlm_init->nlmclnt_ops;
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return host;
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out_nobind:
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nlmclnt_release_host(host);
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out_nohost:
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lockd_down(nlm_init->net);
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return ERR_PTR(-ENOLCK);
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}
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EXPORT_SYMBOL_GPL(nlmclnt_init);
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/**
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* nlmclnt_done - Release resources allocated by nlmclnt_init()
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* @host: nlm_host structure reserved by nlmclnt_init()
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*
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*/
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void nlmclnt_done(struct nlm_host *host)
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{
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struct net *net = host->net;
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nlmclnt_release_host(host);
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lockd_down(net);
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}
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EXPORT_SYMBOL_GPL(nlmclnt_done);
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void nlmclnt_prepare_block(struct nlm_wait *block, struct nlm_host *host, struct file_lock *fl)
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{
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block->b_host = host;
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block->b_lock = fl;
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init_waitqueue_head(&block->b_wait);
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block->b_status = nlm_lck_blocked;
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}
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struct rpc_clnt *nlmclnt_rpc_clnt(struct nlm_host *host)
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{
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return host->h_rpcclnt;
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}
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EXPORT_SYMBOL_GPL(nlmclnt_rpc_clnt);
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/*
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* Queue up a lock for blocking so that the GRANTED request can see it
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*/
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void nlmclnt_queue_block(struct nlm_wait *block)
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{
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spin_lock(&nlm_blocked_lock);
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list_add(&block->b_list, &nlm_blocked);
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spin_unlock(&nlm_blocked_lock);
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}
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/*
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* Dequeue the block and return its final status
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*/
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__be32 nlmclnt_dequeue_block(struct nlm_wait *block)
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{
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__be32 status;
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spin_lock(&nlm_blocked_lock);
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list_del(&block->b_list);
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status = block->b_status;
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spin_unlock(&nlm_blocked_lock);
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return status;
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}
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/*
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* Block on a lock
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*/
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int nlmclnt_wait(struct nlm_wait *block, struct nlm_rqst *req, long timeout)
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{
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long ret;
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/* A borken server might ask us to block even if we didn't
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* request it. Just say no!
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*/
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if (block == NULL)
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return -EAGAIN;
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/* Go to sleep waiting for GRANT callback. Some servers seem
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* to lose callbacks, however, so we're going to poll from
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* time to time just to make sure.
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*
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* For now, the retry frequency is pretty high; normally
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* a 1 minute timeout would do. See the comment before
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* nlmclnt_lock for an explanation.
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*/
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ret = wait_event_interruptible_timeout(block->b_wait,
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block->b_status != nlm_lck_blocked,
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timeout);
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if (ret < 0)
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return -ERESTARTSYS;
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/* Reset the lock status after a server reboot so we resend */
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if (block->b_status == nlm_lck_denied_grace_period)
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block->b_status = nlm_lck_blocked;
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return 0;
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}
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/*
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* The server lockd has called us back to tell us the lock was granted
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*/
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__be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
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{
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const struct file_lock *fl = &lock->fl;
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const struct nfs_fh *fh = &lock->fh;
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struct nlm_wait *block;
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__be32 res = nlm_lck_denied;
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/*
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* Look up blocked request based on arguments.
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* Warning: must not use cookie to match it!
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*/
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spin_lock(&nlm_blocked_lock);
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list_for_each_entry(block, &nlm_blocked, b_list) {
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struct file_lock *fl_blocked = block->b_lock;
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if (fl_blocked->fl_start != fl->fl_start)
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continue;
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if (fl_blocked->fl_end != fl->fl_end)
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continue;
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/*
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* Careful! The NLM server will return the 32-bit "pid" that
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* we put on the wire: in this case the lockowner "pid".
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*/
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if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid)
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continue;
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if (!rpc_cmp_addr(nlm_addr(block->b_host), addr))
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continue;
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if (nfs_compare_fh(NFS_FH(file_inode(fl_blocked->fl_file)), fh) != 0)
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continue;
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/* Alright, we found a lock. Set the return status
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* and wake up the caller
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*/
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block->b_status = nlm_granted;
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wake_up(&block->b_wait);
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res = nlm_granted;
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}
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spin_unlock(&nlm_blocked_lock);
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trace_nlmclnt_grant(lock, addr, svc_addr_len(addr), res);
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return res;
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}
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/*
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* The following procedures deal with the recovery of locks after a
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* server crash.
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*/
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/*
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* Reclaim all locks on server host. We do this by spawning a separate
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* reclaimer thread.
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*/
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void
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nlmclnt_recovery(struct nlm_host *host)
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{
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struct task_struct *task;
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if (!host->h_reclaiming++) {
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nlm_get_host(host);
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task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name);
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if (IS_ERR(task))
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printk(KERN_ERR "lockd: unable to spawn reclaimer "
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"thread. Locks for %s won't be reclaimed! "
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"(%ld)\n", host->h_name, PTR_ERR(task));
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}
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}
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static int
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reclaimer(void *ptr)
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{
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struct nlm_host *host = (struct nlm_host *) ptr;
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struct nlm_wait *block;
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struct nlm_rqst *req;
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struct file_lock *fl, *next;
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u32 nsmstate;
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struct net *net = host->net;
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req = kmalloc(sizeof(*req), GFP_KERNEL);
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if (!req)
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return 0;
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allow_signal(SIGKILL);
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down_write(&host->h_rwsem);
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lockd_up(net, NULL); /* note: this cannot fail as lockd is already running */
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dprintk("lockd: reclaiming locks for host %s\n", host->h_name);
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restart:
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nsmstate = host->h_nsmstate;
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/* Force a portmap getport - the peer's lockd will
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* most likely end up on a different port.
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*/
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host->h_nextrebind = jiffies;
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nlm_rebind_host(host);
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/* First, reclaim all locks that have been granted. */
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list_splice_init(&host->h_granted, &host->h_reclaim);
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list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
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list_del_init(&fl->fl_u.nfs_fl.list);
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/*
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* sending this thread a SIGKILL will result in any unreclaimed
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* locks being removed from the h_granted list. This means that
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* the kernel will not attempt to reclaim them again if a new
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* reclaimer thread is spawned for this host.
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*/
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if (signalled())
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continue;
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if (nlmclnt_reclaim(host, fl, req) != 0)
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continue;
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list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
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if (host->h_nsmstate != nsmstate) {
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/* Argh! The server rebooted again! */
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goto restart;
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}
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}
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host->h_reclaiming = 0;
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up_write(&host->h_rwsem);
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dprintk("NLM: done reclaiming locks for host %s\n", host->h_name);
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/* Now, wake up all processes that sleep on a blocked lock */
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spin_lock(&nlm_blocked_lock);
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list_for_each_entry(block, &nlm_blocked, b_list) {
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if (block->b_host == host) {
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block->b_status = nlm_lck_denied_grace_period;
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wake_up(&block->b_wait);
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}
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}
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spin_unlock(&nlm_blocked_lock);
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/* Release host handle after use */
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nlmclnt_release_host(host);
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lockd_down(net);
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kfree(req);
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return 0;
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}
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