ocfs2: Change the recovery map to an array of node numbers.

The old recovery map was a bitmap of node numbers.  This was sufficient
for the maximum node number of 254.  Going forward, we want node numbers
to be UINT32.  Thus, we need a new recovery map.

Note that we can't keep track of slots here.  We must write down the
node number to recovery *before* we get the locks needed to convert a
node number into a slot number.

The recovery map is now an array of unsigned ints, max_slots in size.
It moves to journal.c with the rest of recovery.

Because it needs to be initialized, we move all of recovery initialization
into a new function, ocfs2_recovery_init().  This actually cleans up
ocfs2_initialize_super() a little as well.  Following on, recovery cleaup
becomes part of ocfs2_recovery_exit().

A number of node map functions are rendered obsolete and are removed.

Finally, waiting on recovery is wrapped in a function rather than naked
checks on the recovery_event.  This is a cleanup from Mark.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 166 insertions, 15 deletions

diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index ed0c6d0850d7..ca4c0ea5a4cd 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -64,6 +64,137 @@ static int ocfs2_recover_orphans(struct ocfs2_super *osb,
                                  int slot);
 static int ocfs2_commit_thread(void *arg);
 
+
+/*
+ * The recovery_list is a simple linked list of node numbers to recover.
+ * It is protected by the recovery_lock.
+ */
+
+struct ocfs2_recovery_map {
+        int rm_used;
+        unsigned int *rm_entries;
+};
+
+int ocfs2_recovery_init(struct ocfs2_super *osb)
+{
+        struct ocfs2_recovery_map *rm;
+
+        mutex_init(&osb->recovery_lock);
+        osb->disable_recovery = 0;
+        osb->recovery_thread_task = NULL;
+        init_waitqueue_head(&osb->recovery_event);
+
+        rm = kzalloc(sizeof(struct ocfs2_recovery_map) +
+                     osb->max_slots * sizeof(unsigned int),
+                     GFP_KERNEL);
+        if (!rm) {
+                mlog_errno(-ENOMEM);
+                return -ENOMEM;
+        }
+
+        rm->rm_entries = (unsigned int *)((char *)rm +
+                                          sizeof(struct ocfs2_recovery_map));
+        osb->recovery_map = rm;
+
+        return 0;
+}
+
+/* we can't grab the goofy sem lock from inside wait_event, so we use
+ * memory barriers to make sure that we'll see the null task before
+ * being woken up */
+static int ocfs2_recovery_thread_running(struct ocfs2_super *osb)
+{
+        mb();
+        return osb->recovery_thread_task != NULL;
+}
+
+void ocfs2_recovery_exit(struct ocfs2_super *osb)
+{
+        struct ocfs2_recovery_map *rm;
+
+        /* disable any new recovery threads and wait for any currently
+         * running ones to exit. Do this before setting the vol_state. */
+        mutex_lock(&osb->recovery_lock);
+        osb->disable_recovery = 1;
+        mutex_unlock(&osb->recovery_lock);
+        wait_event(osb->recovery_event, !ocfs2_recovery_thread_running(osb));
+
+        /* At this point, we know that no more recovery threads can be
+         * launched, so wait for any recovery completion work to
+         * complete. */
+        flush_workqueue(ocfs2_wq);
+
+        /*
+         * Now that recovery is shut down, and the osb is about to be
+         * freed,  the osb_lock is not taken here.
+         */
+        rm = osb->recovery_map;
+        /* XXX: Should we bug if there are dirty entries? */
+
+        kfree(rm);
+}
+
+static int __ocfs2_recovery_map_test(struct ocfs2_super *osb,
+                                     unsigned int node_num)
+{
+        int i;
+        struct ocfs2_recovery_map *rm = osb->recovery_map;
+
+        assert_spin_locked(&osb->osb_lock);
+
+        for (i = 0; i < rm->rm_used; i++) {
+                if (rm->rm_entries[i] == node_num)
+                        return 1;
+        }
+
+        return 0;
+}
+
+/* Behaves like test-and-set.  Returns the previous value */
+static int ocfs2_recovery_map_set(struct ocfs2_super *osb,
+                                  unsigned int node_num)
+{
+        struct ocfs2_recovery_map *rm = osb->recovery_map;
+
+        spin_lock(&osb->osb_lock);
+        if (__ocfs2_recovery_map_test(osb, node_num)) {
+                spin_unlock(&osb->osb_lock);
+                return 1;
+        }
+
+        /* XXX: Can this be exploited? Not from o2dlm... */
+        BUG_ON(rm->rm_used >= osb->max_slots);
+
+        rm->rm_entries[rm->rm_used] = node_num;
+        rm->rm_used++;
+        spin_unlock(&osb->osb_lock);
+
+        return 0;
+}
+
+static void ocfs2_recovery_map_clear(struct ocfs2_super *osb,
+                                     unsigned int node_num)
+{
+        int i;
+        struct ocfs2_recovery_map *rm = osb->recovery_map;
+
+        spin_lock(&osb->osb_lock);
+
+        for (i = 0; i < rm->rm_used; i++) {
+                if (rm->rm_entries[i] == node_num)
+                        break;
+        }
+
+        if (i < rm->rm_used) {
+                /* XXX: be careful with the pointer math */
+                memmove(&(rm->rm_entries[i]), &(rm->rm_entries[i + 1]),
+                        (rm->rm_used - i - 1) * sizeof(unsigned int));
+                rm->rm_used--;
+        }
+
+        spin_unlock(&osb->osb_lock);
+}
+
 static int ocfs2_commit_cache(struct ocfs2_super *osb)
 {
         int status = 0;
@@ -650,6 +781,23 @@ bail:
         return status;
 }
 
+static int ocfs2_recovery_completed(struct ocfs2_super *osb)
+{
+        int empty;
+        struct ocfs2_recovery_map *rm = osb->recovery_map;
+
+        spin_lock(&osb->osb_lock);
+        empty = (rm->rm_used == 0);
+        spin_unlock(&osb->osb_lock);
+
+        return empty;
+}
+
+void ocfs2_wait_for_recovery(struct ocfs2_super *osb)
+{
+        wait_event(osb->recovery_event, ocfs2_recovery_completed(osb));
+}
+
 /*
  * JBD Might read a cached version of another nodes journal file. We
  * don't want this as this file changes often and we get no
@@ -848,6 +996,7 @@ static int __ocfs2_recovery_thread(void *arg)
 {
         int status, node_num;
         struct ocfs2_super *osb = arg;
+        struct ocfs2_recovery_map *rm = osb->recovery_map;
 
         mlog_entry_void();
 
@@ -863,26 +1012,29 @@ restart:
                 goto bail;
         }
 
-        while(!ocfs2_node_map_is_empty(osb, &osb->recovery_map)) {
-                node_num = ocfs2_node_map_first_set_bit(osb,
-                                                        &osb->recovery_map);
-                if (node_num == O2NM_INVALID_NODE_NUM) {
-                        mlog(0, "Out of nodes to recover.\n");
-                        break;
-                }
+        spin_lock(&osb->osb_lock);
+        while (rm->rm_used) {
+                /* It's always safe to remove entry zero, as we won't
+                 * clear it until ocfs2_recover_node() has succeeded. */
+                node_num = rm->rm_entries[0];
+                spin_unlock(&osb->osb_lock);
 
                 status = ocfs2_recover_node(osb, node_num);
-                if (status < 0) {
+                if (!status) {
+                        ocfs2_recovery_map_clear(osb, node_num);
+                } else {
                         mlog(ML_ERROR,
                              "Error %d recovering node %d on device (%u,%u)!\n",
                              status, node_num,
                              MAJOR(osb->sb->s_dev), MINOR(osb->sb->s_dev));
                         mlog(ML_ERROR, "Volume requires unmount.\n");
-                        continue;
                 }
 
-                ocfs2_recovery_map_clear(osb, node_num);
+                spin_lock(&osb->osb_lock);
         }
+        spin_unlock(&osb->osb_lock);
+        mlog(0, "All nodes recovered\n");
+
         ocfs2_super_unlock(osb, 1);
 
         /* We always run recovery on our own orphan dir - the dead
@@ -893,8 +1045,7 @@ restart:
 
 bail:
         mutex_lock(&osb->recovery_lock);
-        if (!status &&
-            !ocfs2_node_map_is_empty(osb, &osb->recovery_map)) {
+        if (!status && !ocfs2_recovery_completed(osb)) {
                 mutex_unlock(&osb->recovery_lock);
                 goto restart;
         }
@@ -924,8 +1075,8 @@ void ocfs2_recovery_thread(struct ocfs2_super *osb, int node_num)
 
         /* People waiting on recovery will wait on
          * the recovery map to empty. */
-        if (!ocfs2_recovery_map_set(osb, node_num))
-                mlog(0, "node %d already be in recovery.\n", node_num);
+        if (ocfs2_recovery_map_set(osb, node_num))
+                mlog(0, "node %d already in recovery map.\n", node_num);
 
         mlog(0, "starting recovery thread...\n");
 
@@ -1197,7 +1348,7 @@ int ocfs2_mark_dead_nodes(struct ocfs2_super *osb)
                 if (status == -ENOENT)
                         continue;
 
-                if (ocfs2_node_map_test_bit(osb, &osb->recovery_map, node_num))
+                if (__ocfs2_recovery_map_test(osb, node_num))
                         continue;
                 spin_unlock(&osb->osb_lock);