4 files changed, 46 insertions, 113 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 42b03c4ee494..17ad92c29cfd 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -845,7 +845,6 @@ struct btrfs_fs_info {
         atomic_t async_submit_draining;
         atomic_t nr_async_bios;
         atomic_t async_delalloc_pages;
-        atomic_t async_caching_threads;
 
         /*
          * this is used by the balancing code to wait for all the pending
@@ -1926,7 +1925,7 @@ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root, unsigned long count);
 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len);
 int btrfs_update_pinned_extents(struct btrfs_root *root,
-                                u64 bytenr, u64 num, int pin, int mark_free);
+                                u64 bytenr, u64 num, int pin);
 int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root, struct extent_buffer *leaf);
 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
@@ -2011,7 +2010,7 @@ void btrfs_delalloc_reserve_space(struct btrfs_root *root, struct inode *inode,
                                  u64 bytes);
 void btrfs_delalloc_free_space(struct btrfs_root *root, struct inode *inode,
                               u64 bytes);
-void btrfs_free_super_mirror_extents(struct btrfs_fs_info *info);
+void btrfs_free_pinned_extents(struct btrfs_fs_info *info);
 /* ctree.c */
 int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
                      int level, int *slot);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index ec2c915f7f4a..c658397c7473 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1567,7 +1567,6 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         atomic_set(&fs_info->async_delalloc_pages, 0);
         atomic_set(&fs_info->async_submit_draining, 0);
         atomic_set(&fs_info->nr_async_bios, 0);
-        atomic_set(&fs_info->async_caching_threads, 0);
         fs_info->sb = sb;
         fs_info->max_extent = (u64)-1;
         fs_info->max_inline = 8192 * 1024;
@@ -2339,7 +2338,7 @@ int close_ctree(struct btrfs_root *root)
         free_extent_buffer(root->fs_info->csum_root->commit_root);
 
         btrfs_free_block_groups(root->fs_info);
-        btrfs_free_super_mirror_extents(root->fs_info);
+        btrfs_free_pinned_extents(root->fs_info);
 
         del_fs_roots(fs_info);
 
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 508df5f7d2ea..08188f1615d9 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -153,18 +153,26 @@ block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
         return ret;
 }
 
-void btrfs_free_super_mirror_extents(struct btrfs_fs_info *info)
+/*
+ * We always set EXTENT_LOCKED for the super mirror extents so we don't
+ * overwrite them, so those bits need to be unset.  Also, if we are unmounting
+ * with pinned extents still sitting there because we had a block group caching,
+ * we need to clear those now, since we are done.
+ */
+void btrfs_free_pinned_extents(struct btrfs_fs_info *info)
 {
         u64 start, end, last = 0;
         int ret;
 
         while (1) {
                 ret = find_first_extent_bit(&info->pinned_extents, last,
-                                            &start, &end, EXTENT_LOCKED);
+                                            &start, &end,
+                                            EXTENT_LOCKED|EXTENT_DIRTY);
                 if (ret)
                         break;
 
-                unlock_extent(&info->pinned_extents, start, end, GFP_NOFS);
+                clear_extent_bits(&info->pinned_extents, start, end,
+                                  EXTENT_LOCKED|EXTENT_DIRTY, GFP_NOFS);
                 last = end+1;
         }
 }
@@ -209,8 +217,7 @@ static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
         while (start < end) {
                 ret = find_first_extent_bit(&info->pinned_extents, start,
                                             &extent_start, &extent_end,
-                                            EXTENT_DIRTY|EXTENT_LOCKED|
-                                            EXTENT_DELALLOC);
+                                            EXTENT_DIRTY|EXTENT_LOCKED);
                 if (ret)
                         break;
 
@@ -238,67 +245,6 @@ static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
         return total_added;
 }
 
-DEFINE_MUTEX(discard_mutex);
-
-/*
- * if async kthreads are running when we cross transactions, we mark any pinned
- * extents with EXTENT_DELALLOC and then let the caching kthreads clean up those
- * extents when they are done.  Also we run this from btrfs_finish_extent_commit
- * in case there were some pinned extents that were missed because we had
- * already cached that block group.
- */
-static void btrfs_discard_pinned_extents(struct btrfs_fs_info *fs_info,
-                                         struct btrfs_block_group_cache *cache)
-{
-        u64 start, end, last;
-        int ret;
-
-        if (!cache)
-                last = 0;
-        else
-                last = cache->key.objectid;
-
-        mutex_lock(&discard_mutex);
-        while (1) {
-                ret = find_first_extent_bit(&fs_info->pinned_extents, last,
-                                            &start, &end, EXTENT_DELALLOC);
-                if (ret)
-                        break;
-
-                if (cache && start >= cache->key.objectid + cache->key.offset)
-                        break;
-
-
-                if (!cache) {
-                        cache = btrfs_lookup_block_group(fs_info, start);
-                        BUG_ON(!cache);
-
-                        start = max(start, cache->key.objectid);
-                        end = min(end, cache->key.objectid + cache->key.offset - 1);
-
-                        if (block_group_cache_done(cache))
-                                btrfs_add_free_space(cache, start,
-                                                     end - start + 1);
-                        cache = NULL;
-                } else {
-                        start = max(start, cache->key.objectid);
-                        end = min(end, cache->key.objectid + cache->key.offset - 1);
-                        btrfs_add_free_space(cache, start, end - start + 1);
-                }
-
-                clear_extent_bits(&fs_info->pinned_extents, start, end,
-                                  EXTENT_DELALLOC, GFP_NOFS);
-                last = end + 1;
-
-                if (need_resched()) {
-                        mutex_unlock(&discard_mutex);
-                        cond_resched();
-                        mutex_lock(&discard_mutex);
-                }
-        }
-        mutex_unlock(&discard_mutex);
-}
-
 static int caching_kthread(void *data)
 {
         struct btrfs_block_group_cache *block_group = data;
@@ -317,7 +263,6 @@ static int caching_kthread(void *data)
         if (!path)
                 return -ENOMEM;
 
-        atomic_inc(&fs_info->async_caching_threads);
         atomic_inc(&block_group->space_info->caching_threads);
         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 again:
@@ -399,13 +344,9 @@ next:
 err:
         btrfs_free_path(path);
         up_read(&fs_info->extent_root->commit_root_sem);
-        atomic_dec(&fs_info->async_caching_threads);
         atomic_dec(&block_group->space_info->caching_threads);
         wake_up(&block_group->caching_q);
 
-        if (!ret)
-                btrfs_discard_pinned_extents(fs_info, block_group);
-
         return 0;
 }
 
@@ -1867,7 +1808,7 @@ static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
                                 BUG_ON(ret);
                         }
                         btrfs_update_pinned_extents(root, node->bytenr,
-                                                    node->num_bytes, 1, 0);
+                                                    node->num_bytes, 1);
                         update_reserved_extents(root, node->bytenr,
                                                 node->num_bytes, 0);
                 }
@@ -3100,19 +3041,15 @@ static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
 }
 
 int btrfs_update_pinned_extents(struct btrfs_root *root,
-                                u64 bytenr, u64 num, int pin, int mark_free)
+                                u64 bytenr, u64 num, int pin)
 {
         u64 len;
         struct btrfs_block_group_cache *cache;
         struct btrfs_fs_info *fs_info = root->fs_info;
 
-        if (pin) {
+        if (pin)
                 set_extent_dirty(&fs_info->pinned_extents,
                                 bytenr, bytenr + num - 1, GFP_NOFS);
-        } else {
-                clear_extent_dirty(&fs_info->pinned_extents,
-                                bytenr, bytenr + num - 1, GFP_NOFS);
-        }
 
         while (num > 0) {
                 cache = btrfs_lookup_block_group(fs_info, bytenr);
@@ -3128,14 +3065,34 @@ int btrfs_update_pinned_extents(struct btrfs_root *root,
                         spin_unlock(&cache->space_info->lock);
                         fs_info->total_pinned += len;
                 } else {
+                        int unpin = 0;
+
+                        /*
+                         * in order to not race with the block group caching, we
+                         * only want to unpin the extent if we are cached.  If
+                         * we aren't cached, we want to start async caching this
+                         * block group so we can free the extent the next time
+                         * around.
+                         */
                         spin_lock(&cache->space_info->lock);
                         spin_lock(&cache->lock);
-                        cache->pinned -= len;
-                        cache->space_info->bytes_pinned -= len;
+                        unpin = (cache->cached == BTRFS_CACHE_FINISHED);
+                        if (likely(unpin)) {
+                                cache->pinned -= len;
+                                cache->space_info->bytes_pinned -= len;
+                                fs_info->total_pinned -= len;
+                        }
                         spin_unlock(&cache->lock);
                         spin_unlock(&cache->space_info->lock);
-                        fs_info->total_pinned -= len;
-                        if (block_group_cache_done(cache) && mark_free)
+
+                        if (likely(unpin))
+                                clear_extent_dirty(&fs_info->pinned_extents,
+                                                   bytenr, bytenr + len -1,
+                                                   GFP_NOFS);
+                        else
+                                cache_block_group(cache);
+
+                        if (unpin)
                                 btrfs_add_free_space(cache, bytenr, len);
                 }
                 btrfs_put_block_group(cache);
@@ -3181,27 +3138,15 @@ int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
         u64 last = 0;
         u64 start;
         u64 end;
-        bool caching_kthreads = false;
         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
         int ret;
 
-        if (atomic_read(&root->fs_info->async_caching_threads))
-                caching_kthreads = true;
-
         while (1) {
                 ret = find_first_extent_bit(pinned_extents, last,
                                             &start, &end, EXTENT_DIRTY);
                 if (ret)
                         break;
 
-                /*
-                 * we need to make sure that the pinned extents don't go away
-                 * while we are caching block groups
-                 */
-                if (unlikely(caching_kthreads))
-                        set_extent_delalloc(pinned_extents, start, end,
-                                            GFP_NOFS);
-
                 set_extent_dirty(copy, start, end, GFP_NOFS);
                 last = end + 1;
         }
@@ -3215,12 +3160,6 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
         u64 start;
         u64 end;
         int ret;
-        int mark_free = 1;
-
-        ret = find_first_extent_bit(&root->fs_info->pinned_extents, 0,
-                                    &start, &end, EXTENT_DELALLOC);
-        if (!ret)
-                mark_free = 0;
 
         while (1) {
                 ret = find_first_extent_bit(unpin, 0, &start, &end,
@@ -3231,16 +3170,12 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
                 ret = btrfs_discard_extent(root, start, end + 1 - start);
 
                 /* unlocks the pinned mutex */
-                btrfs_update_pinned_extents(root, start, end + 1 - start, 0,
-                                            mark_free);
+                btrfs_update_pinned_extents(root, start, end + 1 - start, 0);
                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
 
                 cond_resched();
         }
 
-        if (unlikely(!mark_free))
-                btrfs_discard_pinned_extents(root->fs_info, NULL);
-
         return ret;
 }
 
@@ -3281,7 +3216,7 @@ static int pin_down_bytes(struct btrfs_trans_handle *trans,
 pinit:
         btrfs_set_path_blocking(path);
         /* unlocks the pinned mutex */
-        btrfs_update_pinned_extents(root, bytenr, num_bytes, 1, 0);
+        btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
 
         BUG_ON(err < 0);
         return 0;
@@ -3592,7 +3527,7 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans,
         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
                 /* unlocks the pinned mutex */
-                btrfs_update_pinned_extents(root, bytenr, num_bytes, 1, 0);
+                btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
                 update_reserved_extents(root, bytenr, num_bytes, 0);
                 ret = 0;
         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 11d0787c6188..d91b0de7c502 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -264,7 +264,7 @@ static int process_one_buffer(struct btrfs_root *log,
 {
         if (wc->pin)
                 btrfs_update_pinned_extents(log->fs_info->extent_root,
-                                            eb->start, eb->len, 1, 0);
+                                            eb->start, eb->len, 1);
 
         if (btrfs_buffer_uptodate(eb, gen)) {
                 if (wc->write)