1 files changed, 186 insertions, 12 deletions

diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c
index b05ce6642919..f71658adddb5 100644
--- a/fs/ocfs2/localalloc.c
+++ b/fs/ocfs2/localalloc.c
@@ -73,16 +73,51 @@ static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
 static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
                                           struct inode *local_alloc_inode);
 
+static inline int ocfs2_la_state_enabled(struct ocfs2_super *osb)
+{
+        return (osb->local_alloc_state == OCFS2_LA_THROTTLED ||
+                osb->local_alloc_state == OCFS2_LA_ENABLED);
+}
+
+void ocfs2_local_alloc_seen_free_bits(struct ocfs2_super *osb,
+                                      unsigned int num_clusters)
+{
+        spin_lock(&osb->osb_lock);
+        if (osb->local_alloc_state == OCFS2_LA_DISABLED ||
+            osb->local_alloc_state == OCFS2_LA_THROTTLED)
+                if (num_clusters >= osb->local_alloc_default_bits) {
+                        cancel_delayed_work(&osb->la_enable_wq);
+                        osb->local_alloc_state = OCFS2_LA_ENABLED;
+                }
+        spin_unlock(&osb->osb_lock);
+}
+
+void ocfs2_la_enable_worker(struct work_struct *work)
+{
+        struct ocfs2_super *osb =
+                container_of(work, struct ocfs2_super,
+                             la_enable_wq.work);
+        spin_lock(&osb->osb_lock);
+        osb->local_alloc_state = OCFS2_LA_ENABLED;
+        spin_unlock(&osb->osb_lock);
+}
+
 /*
  * Tell us whether a given allocation should use the local alloc
  * file. Otherwise, it has to go to the main bitmap.
+ *
+ * This function does semi-dirty reads of local alloc size and state!
+ * This is ok however, as the values are re-checked once under mutex.
  */
 int ocfs2_alloc_should_use_local(struct ocfs2_super *osb, u64 bits)
 {
-        int la_bits = osb->local_alloc_bits;
         int ret = 0;
+        int la_bits;
+
+        spin_lock(&osb->osb_lock);
+        la_bits = osb->local_alloc_bits;
 
-        if (osb->local_alloc_state != OCFS2_LA_ENABLED)
+        if (!ocfs2_la_state_enabled(osb))
                 goto bail;
 
         /* la_bits should be at least twice the size (in clusters) of
@@ -96,6 +131,7 @@ int ocfs2_alloc_should_use_local(struct ocfs2_super *osb, u64 bits)
 bail:
         mlog(0, "state=%d, bits=%llu, la_bits=%d, ret=%d\n",
              osb->local_alloc_state, (unsigned long long)bits, la_bits, ret);
+        spin_unlock(&osb->osb_lock);
         return ret;
 }
 
@@ -208,6 +244,9 @@ void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb)
 
         mlog_entry_void();
 
+        cancel_delayed_work(&osb->la_enable_wq);
+        flush_workqueue(ocfs2_wq);
+
         if (osb->local_alloc_state == OCFS2_LA_UNUSED)
                 goto out;
 
@@ -445,7 +484,7 @@ out:
 }
 
 /*
- * make sure we've got at least bitswanted contiguous bits in the
+ * make sure we've got at least bits_wanted contiguous bits in the
  * local alloc. You lose them when you drop i_mutex.
  *
  * We will add ourselves to the transaction passed in, but may start
@@ -476,16 +515,18 @@ int ocfs2_reserve_local_alloc_bits(struct ocfs2_super *osb,
 
         mutex_lock(&local_alloc_inode->i_mutex);
 
-        if (osb->local_alloc_state != OCFS2_LA_ENABLED) {
-                status = -ENOSPC;
-                goto bail;
-        }
-
-        if (bits_wanted > osb->local_alloc_bits) {
-                mlog(0, "Asking for more than my max window size!\n");
+        /*
+         * We must double check state and allocator bits because
+         * another process may have changed them while holding i_mutex.
+         */
+        spin_lock(&osb->osb_lock);
+        if (!ocfs2_la_state_enabled(osb) ||
+            (bits_wanted > osb->local_alloc_bits)) {
+                spin_unlock(&osb->osb_lock);
                 status = -ENOSPC;
                 goto bail;
         }
+        spin_unlock(&osb->osb_lock);
 
         alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
 
@@ -513,6 +554,21 @@ int ocfs2_reserve_local_alloc_bits(struct ocfs2_super *osb,
                                 mlog_errno(status);
                         goto bail;
                 }
+
+                /*
+                 * Under certain conditions, the window slide code
+                 * might have reduced the number of bits available or
+                 * disabled the the local alloc entirely. Re-check
+                 * here and return -ENOSPC if necessary.
+                 */
+                status = -ENOSPC;
+                if (!ocfs2_la_state_enabled(osb))
+                        goto bail;
+
+                free_bits = le32_to_cpu(alloc->id1.bitmap1.i_total) -
+                        le32_to_cpu(alloc->id1.bitmap1.i_used);
+                if (bits_wanted > free_bits)
+                        goto bail;
         }
 
         ac->ac_inode = local_alloc_inode;
@@ -780,6 +836,85 @@ bail:
         return status;
 }
 
+enum ocfs2_la_event {
+        OCFS2_LA_EVENT_SLIDE,           /* Normal window slide. */
+        OCFS2_LA_EVENT_FRAGMENTED,      /* The global bitmap has
+                                         * enough bits theoretically
+                                         * free, but a contiguous
+                                         * allocation could not be
+                                         * found. */
+        OCFS2_LA_EVENT_ENOSPC,          /* Global bitmap doesn't have
+                                         * enough bits free to satisfy
+                                         * our request. */
+};
+#define OCFS2_LA_ENABLE_INTERVAL (30 * HZ)
+/*
+ * Given an event, calculate the size of our next local alloc window.
+ *
+ * This should always be called under i_mutex of the local alloc inode
+ * so that local alloc disabling doesn't race with processes trying to
+ * use the allocator.
+ *
+ * Returns the state which the local alloc was left in. This value can
+ * be ignored by some paths.
+ */
+static int ocfs2_recalc_la_window(struct ocfs2_super *osb,
+                                  enum ocfs2_la_event event)
+{
+        unsigned int bits;
+        int state;
+
+        spin_lock(&osb->osb_lock);
+        if (osb->local_alloc_state == OCFS2_LA_DISABLED) {
+                WARN_ON_ONCE(osb->local_alloc_state == OCFS2_LA_DISABLED);
+                goto out_unlock;
+        }
+
+        /*
+         * ENOSPC and fragmentation are treated similarly for now.
+         */
+        if (event == OCFS2_LA_EVENT_ENOSPC ||
+            event == OCFS2_LA_EVENT_FRAGMENTED) {
+                /*
+                 * We ran out of contiguous space in the primary
+                 * bitmap. Drastically reduce the number of bits used
+                 * by local alloc until we have to disable it.
+                 */
+                bits = osb->local_alloc_bits >> 1;
+                if (bits > ocfs2_megabytes_to_clusters(osb->sb, 1)) {
+                        /*
+                         * By setting state to THROTTLED, we'll keep
+                         * the number of local alloc bits used down
+                         * until an event occurs which would give us
+                         * reason to assume the bitmap situation might
+                         * have changed.
+                         */
+                        osb->local_alloc_state = OCFS2_LA_THROTTLED;
+                        osb->local_alloc_bits = bits;
+                } else {
+                        osb->local_alloc_state = OCFS2_LA_DISABLED;
+                }
+                queue_delayed_work(ocfs2_wq, &osb->la_enable_wq,
+                                   OCFS2_LA_ENABLE_INTERVAL);
+                goto out_unlock;
+        }
+
+        /*
+         * Don't increase the size of the local alloc window until we
+         * know we might be able to fulfill the request. Otherwise, we
+         * risk bouncing around the global bitmap during periods of
+         * low space.
+         */
+        if (osb->local_alloc_state != OCFS2_LA_THROTTLED)
+                osb->local_alloc_bits = osb->local_alloc_default_bits;
+
+out_unlock:
+        state = osb->local_alloc_state;
+        spin_unlock(&osb->osb_lock);
+
+        return state;
+}
+
 static int ocfs2_local_alloc_reserve_for_window(struct ocfs2_super *osb,
                                                 struct ocfs2_alloc_context **ac,
                                                 struct inode **bitmap_inode,
@@ -794,12 +929,21 @@ static int ocfs2_local_alloc_reserve_for_window(struct ocfs2_super *osb,
                 goto bail;
         }
 
+retry_enospc:
         (*ac)->ac_bits_wanted = osb->local_alloc_bits;
 
         status = ocfs2_reserve_cluster_bitmap_bits(osb, *ac);
+        if (status == -ENOSPC) {
+                if (ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_ENOSPC) ==
+                    OCFS2_LA_DISABLED)
+                        goto bail;
+
+                ocfs2_free_ac_resource(*ac);
+                memset(*ac, 0, sizeof(struct ocfs2_alloc_context));
+                goto retry_enospc;
+        }
         if (status < 0) {
-                if (status != -ENOSPC)
-                        mlog_errno(status);
+                mlog_errno(status);
                 goto bail;
         }
 
@@ -852,6 +996,34 @@ static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
          * the more specific cluster api to claim bits. */
         status = ocfs2_claim_clusters(osb, handle, ac, osb->local_alloc_bits,
                                       &cluster_off, &cluster_count);
+        if (status == -ENOSPC) {
+retry_enospc:
+                /*
+                 * Note: We could also try syncing the journal here to
+                 * allow use of any free bits which the current
+                 * transaction can't give us access to. --Mark
+                 */
+                if (ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_FRAGMENTED) ==
+                    OCFS2_LA_DISABLED)
+                        goto bail;
+
+                status = ocfs2_claim_clusters(osb, handle, ac,
+                                              osb->local_alloc_bits,
+                                              &cluster_off,
+                                              &cluster_count);
+                if (status == -ENOSPC)
+                        goto retry_enospc;
+                /*
+                 * We only shrunk the *minimum* number of in our
+                 * request - it's entirely possible that the allocator
+                 * might give us more than we asked for.
+                 */
+                if (status == 0) {
+                        spin_lock(&osb->osb_lock);
+                        osb->local_alloc_bits = cluster_count;
+                        spin_unlock(&osb->osb_lock);
+                }
+        }
         if (status < 0) {
                 if (status != -ENOSPC)
                         mlog_errno(status);
@@ -895,6 +1067,8 @@ static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
 
         mlog_entry_void();
 
+        ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_SLIDE);
+
         /* This will lock the main bitmap for us. */
         status = ocfs2_local_alloc_reserve_for_window(osb,
                                                       &ac,