1 files changed, 245 insertions, 0 deletions

diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
new file mode 100644
index 000000000000..ef7103b8c5bd
--- /dev/null
+++ b/fs/lockd/clntlock.c
@@ -0,0 +1,245 @@
+/*
+ * linux/fs/lockd/clntlock.c
+ *
+ * Lock handling for the client side NLM implementation
+ *
+ * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/time.h>
+#include <linux/nfs_fs.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/svc.h>
+#include <linux/lockd/lockd.h>
+#include <linux/smp_lock.h>
+
+#define NLMDBG_FACILITY         NLMDBG_CLIENT
+
+/*
+ * Local function prototypes
+ */
+static int                      reclaimer(void *ptr);
+
+/*
+ * The following functions handle blocking and granting from the
+ * client perspective.
+ */
+
+/*
+ * This is the representation of a blocked client lock.
+ */
+struct nlm_wait {
+        struct nlm_wait *       b_next;         /* linked list */
+        wait_queue_head_t       b_wait;         /* where to wait on */
+        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 */
+};
+
+static struct nlm_wait *        nlm_blocked;
+
+/*
+ * Block on a lock
+ */
+int
+nlmclnt_block(struct nlm_host *host, struct file_lock *fl, u32 *statp)
+{
+        struct nlm_wait block, **head;
+        int             err;
+        u32             pstate;
+
+        block.b_host   = host;
+        block.b_lock   = fl;
+        init_waitqueue_head(&block.b_wait);
+        block.b_status = NLM_LCK_BLOCKED;
+        block.b_next   = nlm_blocked;
+        nlm_blocked    = &block;
+
+        /* Remember pseudo nsm state */
+        pstate = host->h_state;
+
+        /* Go to sleep waiting for GRANT callback. Some servers seem
+         * to lose callbacks, however, so we're going to poll from
+         * time to time just to make sure.
+         *
+         * For now, the retry frequency is pretty high; normally 
+         * a 1 minute timeout would do. See the comment before
+         * nlmclnt_lock for an explanation.
+         */
+        sleep_on_timeout(&block.b_wait, 30*HZ);
+
+        for (head = &nlm_blocked; *head; head = &(*head)->b_next) {
+                if (*head == &block) {
+                        *head = block.b_next;
+                        break;
+                }
+        }
+
+        if (!signalled()) {
+                *statp = block.b_status;
+                return 0;
+        }
+
+        /* Okay, we were interrupted. Cancel the pending request
+         * unless the server has rebooted.
+         */
+        if (pstate == host->h_state && (err = nlmclnt_cancel(host, fl)) < 0)
+                printk(KERN_NOTICE
+                        "lockd: CANCEL call failed (errno %d)\n", -err);
+
+        return -ERESTARTSYS;
+}
+
+/*
+ * The server lockd has called us back to tell us the lock was granted
+ */
+u32
+nlmclnt_grant(struct nlm_lock *lock)
+{
+        struct nlm_wait *block;
+
+        /*
+         * Look up blocked request based on arguments. 
+         * Warning: must not use cookie to match it!
+         */
+        for (block = nlm_blocked; block; block = block->b_next) {
+                if (nlm_compare_locks(block->b_lock, &lock->fl))
+                        break;
+        }
+
+        /* Ooops, no blocked request found. */
+        if (block == NULL)
+                return nlm_lck_denied;
+
+        /* Alright, we found the lock. Set the return status and
+         * wake up the caller.
+         */
+        block->b_status = NLM_LCK_GRANTED;
+        wake_up(&block->b_wait);
+
+        return nlm_granted;
+}
+
+/*
+ * The following procedures deal with the recovery of locks after a
+ * server crash.
+ */
+
+/*
+ * 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->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)
+{
+        if (host->h_reclaiming++) {
+                if (host->h_nsmstate == newstate)
+                        return;
+                nlmclnt_prepare_reclaim(host, newstate);
+        } else {
+                nlmclnt_prepare_reclaim(host, newstate);
+                nlm_get_host(host);
+                __module_get(THIS_MODULE);
+                if (kernel_thread(reclaimer, host, CLONE_KERNEL) < 0)
+                        module_put(THIS_MODULE);
+        }
+}
+
+static int
+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;
+
+        daemonize("%s-reclaim", host->h_name);
+        allow_signal(SIGKILL);
+
+        /* This one ensures that our parent doesn't terminate while the
+         * reclaim is in progress */
+        lock_kernel();
+        lockd_up();
+
+        /* 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);
+
+                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->host != host)
+                        continue;
+                if (!(fl->fl_u.nfs_fl.flags & NFS_LCK_RECLAIM))
+                        continue;
+
+                fl->fl_u.nfs_fl.flags &= ~NFS_LCK_RECLAIM;
+                nlmclnt_reclaim(host, fl);
+                if (signalled())
+                        break;
+                goto restart;
+        }
+
+        host->h_reclaiming = 0;
+
+        /* Now, wake up all processes that sleep on a blocked lock */
+        for (block = nlm_blocked; block; block = block->b_next) {
+                if (block->b_host == host) {
+                        block->b_status = NLM_LCK_DENIED_GRACE_PERIOD;
+                        wake_up(&block->b_wait);
+                }
+        }
+
+        /* Release host handle after use */
+        nlm_release_host(host);
+        lockd_down();
+        unlock_kernel();
+        module_put_and_exit(0);
+}