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323 lines
8.1 KiB
323 lines
8.1 KiB
/*
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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/time.h>
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#include <linux/nfs_fs.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/sunrpc/svc.h>
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#include <linux/lockd/lockd.h>
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#include <linux/smp_lock.h>
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#include <linux/kthread.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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/*
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* This is the representation of a blocked client lock.
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*/
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struct nlm_wait {
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struct list_head b_list; /* linked list */
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wait_queue_head_t b_wait; /* where to wait on */
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struct nlm_host * b_host;
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struct file_lock * b_lock; /* local file lock */
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unsigned short b_reclaim; /* got to reclaim lock */
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__be32 b_status; /* grant callback status */
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};
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static LIST_HEAD(nlm_blocked);
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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();
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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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if (host == NULL) {
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lockd_down();
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return ERR_PTR(-ENOLCK);
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}
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return host;
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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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nlm_release_host(host);
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lockd_down();
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}
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EXPORT_SYMBOL_GPL(nlmclnt_done);
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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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struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl)
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{
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struct nlm_wait *block;
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block = kmalloc(sizeof(*block), GFP_KERNEL);
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if (block != NULL) {
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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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list_add(&block->b_list, &nlm_blocked);
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}
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return block;
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}
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void nlmclnt_finish_block(struct nlm_wait *block)
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{
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if (block == NULL)
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return;
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list_del(&block->b_list);
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kfree(block);
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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_block(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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req->a_res.status = block->b_status;
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return 0;
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}
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#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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static const struct in6_addr *nlmclnt_map_v4addr(const struct sockaddr *sap,
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struct in6_addr *addr_mapped)
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{
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const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
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switch (sap->sa_family) {
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case AF_INET6:
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return &((const struct sockaddr_in6 *)sap)->sin6_addr;
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case AF_INET:
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ipv6_addr_set_v4mapped(sin->sin_addr.s_addr, addr_mapped);
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return addr_mapped;
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}
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return NULL;
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}
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/*
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* If lockd is using a PF_INET6 listener, all incoming requests appear
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* to come from AF_INET6 remotes. The address of AF_INET remotes are
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* mapped to AF_INET6 automatically by the network layer. In case the
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* user passed an AF_INET server address at mount time, ensure both
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* addresses are AF_INET6 before comparing them.
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*/
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static int nlmclnt_cmp_addr(const struct nlm_host *host,
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const struct sockaddr *sap)
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{
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const struct in6_addr *addr1;
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const struct in6_addr *addr2;
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struct in6_addr addr1_mapped;
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struct in6_addr addr2_mapped;
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addr1 = nlmclnt_map_v4addr(nlm_addr(host), &addr1_mapped);
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if (likely(addr1 != NULL)) {
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addr2 = nlmclnt_map_v4addr(sap, &addr2_mapped);
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if (likely(addr2 != NULL))
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return ipv6_addr_equal(addr1, addr2);
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}
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return 0;
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}
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#else /* !(CONFIG_IPV6 || CONFIG_IPV6_MODULE) */
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static int nlmclnt_cmp_addr(const struct nlm_host *host,
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const struct sockaddr *sap)
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{
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return nlm_cmp_addr(nlm_addr(host), sap);
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}
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#endif /* !(CONFIG_IPV6 || CONFIG_IPV6_MODULE) */
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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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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 (!nlmclnt_cmp_addr(block->b_host, addr))
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continue;
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if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_path.dentry->d_inode) ,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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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 file_lock *fl, *next;
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u32 nsmstate;
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allow_signal(SIGKILL);
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down_write(&host->h_rwsem);
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/* This one ensures that our parent doesn't terminate while the
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* reclaim is in progress */
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lock_kernel();
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lockd_up(); /* 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) != 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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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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/* Release host handle after use */
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nlm_release_host(host);
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lockd_down();
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unlock_kernel();
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return 0;
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}
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