1 files changed, 58 insertions, 65 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 4e1b153b7c47..ba58024d40d3 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2252,6 +2252,16 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
                 }
 
                 /*
+                 * We need to try and merge add/drops of the same ref since we
+                 * can run into issues with relocate dropping the implicit ref
+                 * and then it being added back again before the drop can
+                 * finish.  If we merged anything we need to re-loop so we can
+                 * get a good ref.
+                 */
+                btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
+                                         locked_ref);
+
+                /*
                  * locked_ref is the head node, so we have to go one
                  * node back for any delayed ref updates
                  */
@@ -2318,12 +2328,23 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
                 ref->in_tree = 0;
                 rb_erase(&ref->rb_node, &delayed_refs->root);
                 delayed_refs->num_entries--;
-                /*
-                 * we modified num_entries, but as we're currently running
-                 * delayed refs, skip
-                 *     wake_up(&delayed_refs->seq_wait);
-                 * here.
-                 */
+                if (locked_ref) {
+                        /*
+                         * when we play the delayed ref, also correct the
+                         * ref_mod on head
+                         */
+                        switch (ref->action) {
+                        case BTRFS_ADD_DELAYED_REF:
+                        case BTRFS_ADD_DELAYED_EXTENT:
+                                locked_ref->node.ref_mod -= ref->ref_mod;
+                                break;
+                        case BTRFS_DROP_DELAYED_REF:
+                                locked_ref->node.ref_mod += ref->ref_mod;
+                                break;
+                        default:
+                                WARN_ON(1);
+                        }
+                }
                 spin_unlock(&delayed_refs->lock);
 
                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
@@ -2350,22 +2371,6 @@ next:
         return count;
 }
 
-static void wait_for_more_refs(struct btrfs_fs_info *fs_info,
-                               struct btrfs_delayed_ref_root *delayed_refs,
-                               unsigned long num_refs,
-                               struct list_head *first_seq)
-{
-        spin_unlock(&delayed_refs->lock);
-        pr_debug("waiting for more refs (num %ld, first %p)\n",
-                 num_refs, first_seq);
-        wait_event(fs_info->tree_mod_seq_wait,
-                   num_refs != delayed_refs->num_entries ||
-                   fs_info->tree_mod_seq_list.next != first_seq);
-        pr_debug("done waiting for more refs (num %ld, first %p)\n",
-                 delayed_refs->num_entries, fs_info->tree_mod_seq_list.next);
-        spin_lock(&delayed_refs->lock);
-}
-
 #ifdef SCRAMBLE_DELAYED_REFS
 /*
  * Normally delayed refs get processed in ascending bytenr order. This
@@ -2460,13 +2465,11 @@ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
         struct btrfs_delayed_ref_root *delayed_refs;
         struct btrfs_delayed_ref_node *ref;
         struct list_head cluster;
-        struct list_head *first_seq = NULL;
         int ret;
         u64 delayed_start;
         int run_all = count == (unsigned long)-1;
         int run_most = 0;
-        unsigned long num_refs = 0;
-        int consider_waiting;
+        int loops;
 
         /* We'll clean this up in btrfs_cleanup_transaction */
         if (trans->aborted)
@@ -2484,7 +2487,7 @@ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
         delayed_refs = &trans->transaction->delayed_refs;
         INIT_LIST_HEAD(&cluster);
 again:
-        consider_waiting = 0;
+        loops = 0;
         spin_lock(&delayed_refs->lock);
 
 #ifdef SCRAMBLE_DELAYED_REFS
@@ -2512,31 +2515,6 @@ again:
                 if (ret)
                         break;
 
-                if (delayed_start >= delayed_refs->run_delayed_start) {
-                        if (consider_waiting == 0) {
-                                /*
-                                 * btrfs_find_ref_cluster looped. let's do one
-                                 * more cycle. if we don't run any delayed ref
-                                 * during that cycle (because we can't because
-                                 * all of them are blocked) and if the number of
-                                 * refs doesn't change, we avoid busy waiting.
-                                 */
-                                consider_waiting = 1;
-                                num_refs = delayed_refs->num_entries;
-                                first_seq = root->fs_info->tree_mod_seq_list.next;
-                        } else {
-                                wait_for_more_refs(root->fs_info, delayed_refs,
-                                                   num_refs, first_seq);
-                                /*
-                                 * after waiting, things have changed. we
-                                 * dropped the lock and someone else might have
-                                 * run some refs, built new clusters and so on.
-                                 * therefore, we restart staleness detection.
-                                 */
-                                consider_waiting = 0;
-                        }
-                }
-
                 ret = run_clustered_refs(trans, root, &cluster);
                 if (ret < 0) {
                         spin_unlock(&delayed_refs->lock);
@@ -2549,9 +2527,26 @@ again:
                 if (count == 0)
                         break;
 
-                if (ret || delayed_refs->run_delayed_start == 0) {
+                if (delayed_start >= delayed_refs->run_delayed_start) {
+                        if (loops == 0) {
+                                /*
+                                 * btrfs_find_ref_cluster looped. let's do one
+                                 * more cycle. if we don't run any delayed ref
+                                 * during that cycle (because we can't because
+                                 * all of them are blocked), bail out.
+                                 */
+                                loops = 1;
+                        } else {
+                                /*
+                                 * no runnable refs left, stop trying
+                                 */
+                                BUG_ON(run_all);
+                                break;
+                        }
+                }
+                if (ret) {
                         /* refs were run, let's reset staleness detection */
-                        consider_waiting = 0;
+                        loops = 0;
                 }
         }
 
@@ -3007,17 +3002,16 @@ again:
         }
         spin_unlock(&block_group->lock);
 
-        num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
+        /*
+         * Try to preallocate enough space based on how big the block group is.
+         * Keep in mind this has to include any pinned space which could end up
+         * taking up quite a bit since it's not folded into the other space
+         * cache.
+         */
+        num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
         if (!num_pages)
                 num_pages = 1;
 
-        /*
-         * Just to make absolutely sure we have enough space, we're going to
-         * preallocate 12 pages worth of space for each block group.  In
-         * practice we ought to use at most 8, but we need extra space so we can
-         * add our header and have a terminator between the extents and the
-         * bitmaps.
-         */
         num_pages *= 16;
         num_pages *= PAGE_CACHE_SIZE;
 
@@ -4571,8 +4565,10 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         if (root->fs_info->quota_enabled) {
                 ret = btrfs_qgroup_reserve(root, num_bytes +
                                            nr_extents * root->leafsize);
-                if (ret)
+                if (ret) {
+                        mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
                         return ret;
+                }
         }
 
         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
@@ -5294,9 +5290,6 @@ static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
         rb_erase(&head->node.rb_node, &delayed_refs->root);
 
         delayed_refs->num_entries--;
-        smp_mb();
-        if (waitqueue_active(&root->fs_info->tree_mod_seq_wait))
-                wake_up(&root->fs_info->tree_mod_seq_wait);
 
         /*
          * we don't take a ref on the node because we're removing it from the