lockd: convert reclaimer thread to kthread interface
[linux-2.6.git] / fs / lockd / clntlock.c
index 8ae79ae..94d42cc 100644 (file)
@@ -14,6 +14,7 @@
 #include <linux/sunrpc/svc.h>
 #include <linux/lockd/lockd.h>
 #include <linux/smp_lock.h>
+#include <linux/kthread.h>
 
 #define NLMDBG_FACILITY                NLMDBG_CLIENT
 
@@ -36,40 +37,74 @@ struct nlm_wait {
        struct nlm_host *       b_host;
        struct file_lock *      b_lock;         /* local file lock */
        unsigned short          b_reclaim;      /* got to reclaim lock */
-       u32                     b_status;       /* grant callback status */
+       __be32                  b_status;       /* grant callback status */
 };
 
 static LIST_HEAD(nlm_blocked);
 
+/**
+ * nlmclnt_init - Set up per-NFS mount point lockd data structures
+ * @nlm_init: pointer to arguments structure
+ *
+ * Returns pointer to an appropriate nlm_host struct,
+ * or an ERR_PTR value.
+ */
+struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init)
+{
+       struct nlm_host *host;
+       u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4;
+       int status;
+
+       status = lockd_up();
+       if (status < 0)
+               return ERR_PTR(status);
+
+       host = nlmclnt_lookup_host(nlm_init->address, nlm_init->addrlen,
+                                  nlm_init->protocol, nlm_version,
+                                  nlm_init->hostname);
+       if (host == NULL) {
+               lockd_down();
+               return ERR_PTR(-ENOLCK);
+       }
+
+       return host;
+}
+EXPORT_SYMBOL_GPL(nlmclnt_init);
+
+/**
+ * nlmclnt_done - Release resources allocated by nlmclnt_init()
+ * @host: nlm_host structure reserved by nlmclnt_init()
+ *
+ */
+void nlmclnt_done(struct nlm_host *host)
+{
+       nlm_release_host(host);
+       lockd_down();
+}
+EXPORT_SYMBOL_GPL(nlmclnt_done);
+
 /*
  * Queue up a lock for blocking so that the GRANTED request can see it
  */
-int nlmclnt_prepare_block(struct nlm_rqst *req, struct nlm_host *host, struct file_lock *fl)
+struct nlm_wait *nlmclnt_prepare_block(struct nlm_host *host, struct file_lock *fl)
 {
        struct nlm_wait *block;
 
-       BUG_ON(req->a_block != NULL);
        block = kmalloc(sizeof(*block), GFP_KERNEL);
-       if (block == NULL)
-               return -ENOMEM;
-       block->b_host = host;
-       block->b_lock = fl;
-       init_waitqueue_head(&block->b_wait);
-       block->b_status = NLM_LCK_BLOCKED;
-
-       list_add(&block->b_list, &nlm_blocked);
-       req->a_block = block;
-
-       return 0;
+       if (block != NULL) {
+               block->b_host = host;
+               block->b_lock = fl;
+               init_waitqueue_head(&block->b_wait);
+               block->b_status = nlm_lck_blocked;
+               list_add(&block->b_list, &nlm_blocked);
+       }
+       return block;
 }
 
-void nlmclnt_finish_block(struct nlm_rqst *req)
+void nlmclnt_finish_block(struct nlm_wait *block)
 {
-       struct nlm_wait *block = req->a_block;
-
        if (block == NULL)
                return;
-       req->a_block = NULL;
        list_del(&block->b_list);
        kfree(block);
 }
@@ -77,15 +112,14 @@ void nlmclnt_finish_block(struct nlm_rqst *req)
 /*
  * Block on a lock
  */
-long nlmclnt_block(struct nlm_rqst *req, long timeout)
+int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout)
 {
-       struct nlm_wait *block = req->a_block;
        long ret;
 
        /* A borken server might ask us to block even if we didn't
         * request it. Just say no!
         */
-       if (!req->a_args.block)
+       if (block == NULL)
                return -EAGAIN;
 
        /* Go to sleep waiting for GRANT callback. Some servers seem
@@ -97,26 +131,23 @@ long nlmclnt_block(struct nlm_rqst *req, long timeout)
         * nlmclnt_lock for an explanation.
         */
        ret = wait_event_interruptible_timeout(block->b_wait,
-                       block->b_status != NLM_LCK_BLOCKED,
+                       block->b_status != nlm_lck_blocked,
                        timeout);
-
-       if (block->b_status != NLM_LCK_BLOCKED) {
-               req->a_res.status = block->b_status;
-               block->b_status = NLM_LCK_BLOCKED;
-       }
-
-       return ret;
+       if (ret < 0)
+               return -ERESTARTSYS;
+       req->a_res.status = block->b_status;
+       return 0;
 }
 
 /*
  * The server lockd has called us back to tell us the lock was granted
  */
-u32 nlmclnt_grant(const struct sockaddr_in *addr, const struct nlm_lock *lock)
+__be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock)
 {
        const struct file_lock *fl = &lock->fl;
        const struct nfs_fh *fh = &lock->fh;
        struct nlm_wait *block;
-       u32 res = nlm_lck_denied;
+       __be32 res = nlm_lck_denied;
 
        /*
         * Look up blocked request based on arguments. 
@@ -135,14 +166,14 @@ u32 nlmclnt_grant(const struct sockaddr_in *addr, const struct nlm_lock *lock)
                 */
                if (fl_blocked->fl_u.nfs_fl.owner->pid != lock->svid)
                        continue;
-               if (!nlm_cmp_addr(&block->b_host->h_addr, addr))
+               if (!nlm_cmp_addr(nlm_addr(block->b_host), addr))
                        continue;
-               if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_dentry->d_inode) ,fh) != 0)
+               if (nfs_compare_fh(NFS_FH(fl_blocked->fl_file->f_path.dentry->d_inode) ,fh) != 0)
                        continue;
                /* Alright, we found a lock. Set the return status
                 * and wake up the caller
                 */
-               block->b_status = NLM_LCK_GRANTED;
+               block->b_status = nlm_granted;
                wake_up(&block->b_wait);
                res = nlm_granted;
        }
@@ -155,66 +186,21 @@ u32 nlmclnt_grant(const struct sockaddr_in *addr, const struct nlm_lock *lock)
  */
 
 /*
- * Mark the locks for reclaiming.
- * FIXME: In 2.5 we don't want to iterate through any global file_lock_list.
- *        Maintain NLM lock reclaiming lists in the nlm_host instead.
- */
-static
-void nlmclnt_mark_reclaim(struct nlm_host *host)
-{
-       struct file_lock *fl;
-       struct inode *inode;
-       struct list_head *tmp;
-
-       list_for_each(tmp, &file_lock_list) {
-               fl = list_entry(tmp, struct file_lock, fl_link);
-
-               inode = fl->fl_file->f_dentry->d_inode;
-               if (inode->i_sb->s_magic != NFS_SUPER_MAGIC)
-                       continue;
-               if (fl->fl_u.nfs_fl.owner == NULL)
-                       continue;
-               if (fl->fl_u.nfs_fl.owner->host != host)
-                       continue;
-               if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_GRANTED))
-                       continue;
-               fl->fl_u.nfs_fl.flags |= NFS_LCK_RECLAIM;
-       }
-}
-
-/*
- * Someone has sent us an SM_NOTIFY. Ensure we bind to the new port number,
- * that we mark locks for reclaiming, and that we bump the pseudo NSM state.
- */
-static inline
-void nlmclnt_prepare_reclaim(struct nlm_host *host, u32 newstate)
-{
-       host->h_monitored = 0;
-       host->h_nsmstate = newstate;
-       host->h_state++;
-       host->h_nextrebind = 0;
-       nlm_rebind_host(host);
-       nlmclnt_mark_reclaim(host);
-       dprintk("NLM: reclaiming locks for host %s", host->h_name);
-}
-
-/*
  * Reclaim all locks on server host. We do this by spawning a separate
  * reclaimer thread.
  */
 void
-nlmclnt_recovery(struct nlm_host *host, u32 newstate)
+nlmclnt_recovery(struct nlm_host *host)
 {
-       if (host->h_reclaiming++) {
-               if (host->h_nsmstate == newstate)
-                       return;
-               nlmclnt_prepare_reclaim(host, newstate);
-       } else {
-               nlmclnt_prepare_reclaim(host, newstate);
+       struct task_struct *task;
+
+       if (!host->h_reclaiming++) {
                nlm_get_host(host);
-               __module_get(THIS_MODULE);
-               if (kernel_thread(reclaimer, host, CLONE_KERNEL) < 0)
-                       module_put(THIS_MODULE);
+               task = kthread_run(reclaimer, host, "%s-reclaim", host->h_name);
+               if (IS_ERR(task))
+                       printk(KERN_ERR "lockd: unable to spawn reclaimer "
+                               "thread. Locks for %s won't be reclaimed! "
+                               "(%ld)\n", host->h_name, PTR_ERR(task));
        }
 }
 
@@ -223,46 +209,59 @@ reclaimer(void *ptr)
 {
        struct nlm_host   *host = (struct nlm_host *) ptr;
        struct nlm_wait   *block;
-       struct list_head *tmp;
-       struct file_lock *fl;
-       struct inode *inode;
+       struct file_lock *fl, *next;
+       u32 nsmstate;
 
-       daemonize("%s-reclaim", host->h_name);
        allow_signal(SIGKILL);
 
+       down_write(&host->h_rwsem);
+
        /* This one ensures that our parent doesn't terminate while the
         * reclaim is in progress */
        lock_kernel();
-       lockd_up();
+       lockd_up();     /* note: this cannot fail as lockd is already running */
+
+       dprintk("lockd: reclaiming locks for host %s\n", host->h_name);
 
-       /* First, reclaim all locks that have been marked. */
 restart:
-       list_for_each(tmp, &file_lock_list) {
-               fl = list_entry(tmp, struct file_lock, fl_link);
+       nsmstate = host->h_nsmstate;
 
-               inode = fl->fl_file->f_dentry->d_inode;
-               if (inode->i_sb->s_magic != NFS_SUPER_MAGIC)
-                       continue;
-               if (fl->fl_u.nfs_fl.owner == NULL)
-                       continue;
-               if (fl->fl_u.nfs_fl.owner->host != host)
-                       continue;
-               if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_RECLAIM))
-                       continue;
+       /* Force a portmap getport - the peer's lockd will
+        * most likely end up on a different port.
+        */
+       host->h_nextrebind = jiffies;
+       nlm_rebind_host(host);
 
-               fl->fl_u.nfs_fl.flags &= ~NFS_LCK_RECLAIM;
-               nlmclnt_reclaim(host, fl);
+       /* First, reclaim all locks that have been granted. */
+       list_splice_init(&host->h_granted, &host->h_reclaim);
+       list_for_each_entry_safe(fl, next, &host->h_reclaim, fl_u.nfs_fl.list) {
+               list_del_init(&fl->fl_u.nfs_fl.list);
+
+               /*
+                * sending this thread a SIGKILL will result in any unreclaimed
+                * locks being removed from the h_granted list. This means that
+                * the kernel will not attempt to reclaim them again if a new
+                * reclaimer thread is spawned for this host.
+                */
                if (signalled())
-                       break;
-               goto restart;
+                       continue;
+               if (nlmclnt_reclaim(host, fl) != 0)
+                       continue;
+               list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
+               if (host->h_nsmstate != nsmstate) {
+                       /* Argh! The server rebooted again! */
+                       goto restart;
+               }
        }
 
        host->h_reclaiming = 0;
+       up_write(&host->h_rwsem);
+       dprintk("NLM: done reclaiming locks for host %s\n", host->h_name);
 
        /* Now, wake up all processes that sleep on a blocked lock */
        list_for_each_entry(block, &nlm_blocked, b_list) {
                if (block->b_host == host) {
-                       block->b_status = NLM_LCK_DENIED_GRACE_PERIOD;
+                       block->b_status = nlm_lck_denied_grace_period;
                        wake_up(&block->b_wait);
                }
        }
@@ -271,5 +270,5 @@ restart:
        nlm_release_host(host);
        lockd_down();
        unlock_kernel();
-       module_put_and_exit(0);
+       return 0;
 }