4 files changed, 170 insertions, 32 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e305ccd731fe..1df0d9db5332 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1261,9 +1261,12 @@ struct btrfs_io_ctl {
         struct page *page;
         struct page **pages;
         struct btrfs_root *root;
+        struct inode *inode;
         unsigned long size;
         int index;
         int num_pages;
+        int entries;
+        int bitmaps;
         unsigned check_crcs:1;
 };
 
@@ -1332,6 +1335,9 @@ struct btrfs_block_group_cache {
 
         /* For dirty block groups */
         struct list_head dirty_list;
+        struct list_head io_list;
+
+        struct btrfs_io_ctl io_ctl;
 };
 
 /* delayed seq elem */
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 3d4b3d680fea..40c95135d037 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3388,7 +3388,11 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
         struct btrfs_block_group_cache *cache;
         struct btrfs_transaction *cur_trans = trans->transaction;
         int ret = 0;
+        int should_put;
         struct btrfs_path *path;
+        LIST_HEAD(io);
+        int num_started = 0;
+        int num_waited = 0;
 
         if (list_empty(&cur_trans->dirty_bgs))
                 return 0;
@@ -3407,16 +3411,60 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
                 cache = list_first_entry(&cur_trans->dirty_bgs,
                                          struct btrfs_block_group_cache,
                                          dirty_list);
+
+                /*
+                 * this can happen if cache_save_setup re-dirties a block
+                 * group that is already under IO.  Just wait for it to
+                 * finish and then do it all again
+                 */
+                if (!list_empty(&cache->io_list)) {
+                        list_del_init(&cache->io_list);
+                        btrfs_wait_cache_io(root, trans, cache,
+                                            &cache->io_ctl, path,
+                                            cache->key.objectid);
+                        btrfs_put_block_group(cache);
+                        num_waited++;
+                }
+
                 list_del_init(&cache->dirty_list);
+                should_put = 1;
+
                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
                         cache_save_setup(cache, trans, path);
+
                 if (!ret)
-                        ret = btrfs_run_delayed_refs(trans, root,
-                                                     (unsigned long) -1);
-                if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP)
-                        btrfs_write_out_cache(root, trans, cache, path);
+                        ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
+
+                if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
+                        cache->io_ctl.inode = NULL;
+                        ret = btrfs_write_out_cache(root, trans, cache, path);
+                        if (ret == 0 && cache->io_ctl.inode) {
+                                num_started++;
+                                should_put = 0;
+                                list_add_tail(&cache->io_list, &io);
+                        } else {
+                                /*
+                                 * if we failed to write the cache, the
+                                 * generation will be bad and life goes on
+                                 */
+                                ret = 0;
+                        }
+                }
                 if (!ret)
                         ret = write_one_cache_group(trans, root, path, cache);
+
+                /* if its not on the io list, we need to put the block group */
+                if (should_put)
+                        btrfs_put_block_group(cache);
+        }
+
+        while (!list_empty(&io)) {
+                cache = list_first_entry(&io, struct btrfs_block_group_cache,
+                                         io_list);
+                list_del_init(&cache->io_list);
+                num_waited++;
+                btrfs_wait_cache_io(root, trans, cache,
+                                    &cache->io_ctl, path, cache->key.objectid);
                 btrfs_put_block_group(cache);
         }
 
@@ -9013,6 +9061,7 @@ btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
         INIT_LIST_HEAD(&cache->bg_list);
         INIT_LIST_HEAD(&cache->ro_list);
         INIT_LIST_HEAD(&cache->dirty_list);
+        INIT_LIST_HEAD(&cache->io_list);
         btrfs_init_free_space_ctl(cache);
         atomic_set(&cache->trimming, 0);
 
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 47c2adb3ddf3..6886ae063483 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -170,13 +170,13 @@ static int __create_free_space_inode(struct btrfs_root *root,
         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
         key.offset = offset;
         key.type = 0;
-
         ret = btrfs_insert_empty_item(trans, root, path, &key,
                                       sizeof(struct btrfs_free_space_header));
         if (ret < 0) {
                 btrfs_release_path(path);
                 return ret;
         }
+
         leaf = path->nodes[0];
         header = btrfs_item_ptr(leaf, path->slots[0],
                                 struct btrfs_free_space_header);
@@ -296,6 +296,7 @@ static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
         io_ctl->num_pages = num_pages;
         io_ctl->root = root;
         io_ctl->check_crcs = check_crcs;
+        io_ctl->inode = inode;
 
         return 0;
 }
@@ -303,6 +304,7 @@ static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
 static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
 {
         kfree(io_ctl->pages);
+        io_ctl->pages = NULL;
 }
 
 static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
@@ -1092,6 +1094,61 @@ cleanup_write_cache_enospc(struct inode *inode,
                              GFP_NOFS);
 }
 
+int btrfs_wait_cache_io(struct btrfs_root *root,
+                        struct btrfs_trans_handle *trans,
+                        struct btrfs_block_group_cache *block_group,
+                        struct btrfs_io_ctl *io_ctl,
+                        struct btrfs_path *path, u64 offset)
+{
+        int ret;
+        struct inode *inode = io_ctl->inode;
+
+        root = root->fs_info->tree_root;
+
+        /* Flush the dirty pages in the cache file. */
+        ret = flush_dirty_cache(inode);
+        if (ret)
+                goto out;
+
+        /* Update the cache item to tell everyone this cache file is valid. */
+        ret = update_cache_item(trans, root, inode, path, offset,
+                                io_ctl->entries, io_ctl->bitmaps);
+out:
+        io_ctl_free(io_ctl);
+        if (ret) {
+                invalidate_inode_pages2(inode->i_mapping);
+                BTRFS_I(inode)->generation = 0;
+                if (block_group) {
+#ifdef DEBUG
+                        btrfs_err(root->fs_info,
+                                "failed to write free space cache for block group %llu",
+                                block_group->key.objectid);
+#endif
+                }
+        }
+        btrfs_update_inode(trans, root, inode);
+
+        if (block_group) {
+                spin_lock(&block_group->lock);
+
+                /*
+                 * only mark this as written if we didn't get put back on
+                 * the dirty list while waiting for IO.
+                 */
+                if (!ret && list_empty(&block_group->dirty_list))
+                        block_group->disk_cache_state = BTRFS_DC_WRITTEN;
+                else if (ret)
+                        block_group->disk_cache_state = BTRFS_DC_ERROR;
+
+                spin_unlock(&block_group->lock);
+                io_ctl->inode = NULL;
+                iput(inode);
+        }
+
+        return ret;
+
+}
+
 /**
  * __btrfs_write_out_cache - write out cached info to an inode
  * @root - the root the inode belongs to
@@ -1108,20 +1165,22 @@ cleanup_write_cache_enospc(struct inode *inode,
 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
                                    struct btrfs_free_space_ctl *ctl,
                                    struct btrfs_block_group_cache *block_group,
+                                   struct btrfs_io_ctl *io_ctl,
                                    struct btrfs_trans_handle *trans,
                                    struct btrfs_path *path, u64 offset)
 {
         struct extent_state *cached_state = NULL;
-        struct btrfs_io_ctl io_ctl;
         LIST_HEAD(bitmap_list);
         int entries = 0;
         int bitmaps = 0;
         int ret;
+        int must_iput = 0;
 
         if (!i_size_read(inode))
                 return -1;
 
-        ret = io_ctl_init(&io_ctl, inode, root, 1);
+        WARN_ON(io_ctl->pages);
+        ret = io_ctl_init(io_ctl, inode, root, 1);
         if (ret)
                 return -1;
 
@@ -1134,22 +1193,23 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
                         up_write(&block_group->data_rwsem);
                         BTRFS_I(inode)->generation = 0;
                         ret = 0;
+                        must_iput = 1;
                         goto out;
                 }
                 spin_unlock(&block_group->lock);
         }
 
         /* Lock all pages first so we can lock the extent safely. */
-        io_ctl_prepare_pages(&io_ctl, inode, 0);
+        io_ctl_prepare_pages(io_ctl, inode, 0);
 
         lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
                          0, &cached_state);
 
-        io_ctl_set_generation(&io_ctl, trans->transid);
+        io_ctl_set_generation(io_ctl, trans->transid);
 
         mutex_lock(&ctl->cache_writeout_mutex);
         /* Write out the extent entries in the free space cache */
-        ret = write_cache_extent_entries(&io_ctl, ctl,
+        ret = write_cache_extent_entries(io_ctl, ctl,
                                          block_group, &entries, &bitmaps,
                                          &bitmap_list);
         if (ret) {
@@ -1162,7 +1222,7 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
          * they will be added into free space cache after the transaction is
          * committed, we shouldn't lose them.
          */
-        ret = write_pinned_extent_entries(root, block_group, &io_ctl, &entries);
+        ret = write_pinned_extent_entries(root, block_group, io_ctl, &entries);
         if (ret) {
                 mutex_unlock(&ctl->cache_writeout_mutex);
                 goto out_nospc;
@@ -1173,16 +1233,16 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
          * locked while doing it because a concurrent trim can be manipulating
          * or freeing the bitmap.
          */
-        ret = write_bitmap_entries(&io_ctl, &bitmap_list);
+        ret = write_bitmap_entries(io_ctl, &bitmap_list);
         mutex_unlock(&ctl->cache_writeout_mutex);
         if (ret)
                 goto out_nospc;
 
         /* Zero out the rest of the pages just to make sure */
-        io_ctl_zero_remaining_pages(&io_ctl);
+        io_ctl_zero_remaining_pages(io_ctl);
 
         /* Everything is written out, now we dirty the pages in the file. */
-        ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
+        ret = btrfs_dirty_pages(root, inode, io_ctl->pages, io_ctl->num_pages,
                                 0, i_size_read(inode), &cached_state);
         if (ret)
                 goto out_nospc;
@@ -1193,30 +1253,39 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
          * Release the pages and unlock the extent, we will flush
          * them out later
          */
-        io_ctl_drop_pages(&io_ctl);
+        io_ctl_drop_pages(io_ctl);
 
         unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
                              i_size_read(inode) - 1, &cached_state, GFP_NOFS);
 
-        /* Flush the dirty pages in the cache file. */
-        ret = flush_dirty_cache(inode);
+        /*
+         * at this point the pages are under IO and we're happy,
+         * The caller is responsible for waiting on them and updating the
+         * the cache and the inode
+         */
+        io_ctl->entries = entries;
+        io_ctl->bitmaps = bitmaps;
+
+        ret = btrfs_fdatawrite_range(inode, 0, (u64)-1);
         if (ret)
                 goto out;
 
-        /* Update the cache item to tell everyone this cache file is valid. */
-        ret = update_cache_item(trans, root, inode, path, offset,
-                                entries, bitmaps);
+        return 0;
+
 out:
-        io_ctl_free(&io_ctl);
+        io_ctl->inode = NULL;
+        io_ctl_free(io_ctl);
         if (ret) {
                 invalidate_inode_pages2(inode->i_mapping);
                 BTRFS_I(inode)->generation = 0;
         }
         btrfs_update_inode(trans, root, inode);
+        if (must_iput)
+                iput(inode);
         return ret;
 
 out_nospc:
-        cleanup_write_cache_enospc(inode, &io_ctl, &cached_state, &bitmap_list);
+        cleanup_write_cache_enospc(inode, io_ctl, &cached_state, &bitmap_list);
 
         if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
                 up_write(&block_group->data_rwsem);
@@ -1232,7 +1301,6 @@ int btrfs_write_out_cache(struct btrfs_root *root,
         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
         struct inode *inode;
         int ret = 0;
-        enum btrfs_disk_cache_state dcs = BTRFS_DC_WRITTEN;
 
         root = root->fs_info->tree_root;
 
@@ -1253,22 +1321,28 @@ int btrfs_write_out_cache(struct btrfs_root *root,
         if (IS_ERR(inode))
                 return 0;
 
-        ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
+        ret = __btrfs_write_out_cache(root, inode, ctl, block_group,
+                                      &block_group->io_ctl, trans,
                                       path, block_group->key.objectid);
         if (ret) {
-                dcs = BTRFS_DC_ERROR;
-                ret = 0;
 #ifdef DEBUG
                 btrfs_err(root->fs_info,
                         "failed to write free space cache for block group %llu",
                         block_group->key.objectid);
 #endif
+                spin_lock(&block_group->lock);
+                block_group->disk_cache_state = BTRFS_DC_ERROR;
+                spin_unlock(&block_group->lock);
+
+                block_group->io_ctl.inode = NULL;
+                iput(inode);
         }
 
-        spin_lock(&block_group->lock);
-        block_group->disk_cache_state = dcs;
-        spin_unlock(&block_group->lock);
-        iput(inode);
+        /*
+         * if ret == 0 the caller is expected to call btrfs_wait_cache_io
+         * to wait for IO and put the inode
+         */
+
         return ret;
 }
 
@@ -3331,11 +3405,14 @@ int btrfs_write_out_ino_cache(struct btrfs_root *root,
 {
         struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
         int ret;
+        struct btrfs_io_ctl io_ctl;
 
         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
                 return 0;
 
-        ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
+        ret = __btrfs_write_out_cache(root, inode, ctl, NULL, &io_ctl,
+                                      trans, path, 0) ||
+                btrfs_wait_cache_io(root, trans, NULL, &io_ctl, path, 0);
         if (ret) {
                 btrfs_delalloc_release_metadata(inode, inode->i_size);
 #ifdef DEBUG
diff --git a/fs/btrfs/free-space-cache.h b/fs/btrfs/free-space-cache.h
index 88b2238a0aed..c4339863af05 100644
--- a/fs/btrfs/free-space-cache.h
+++ b/fs/btrfs/free-space-cache.h
@@ -48,6 +48,8 @@ struct btrfs_free_space_op {
                            struct btrfs_free_space *info);
 };
 
+struct btrfs_io_ctl;
+
 struct inode *lookup_free_space_inode(struct btrfs_root *root,
                                       struct btrfs_block_group_cache
                                       *block_group, struct btrfs_path *path);
@@ -63,11 +65,15 @@ int btrfs_truncate_free_space_cache(struct btrfs_root *root,
                                     struct inode *inode);
 int load_free_space_cache(struct btrfs_fs_info *fs_info,
                           struct btrfs_block_group_cache *block_group);
+int btrfs_wait_cache_io(struct btrfs_root *root,
+                        struct btrfs_trans_handle *trans,
+                        struct btrfs_block_group_cache *block_group,
+                        struct btrfs_io_ctl *io_ctl,
+                        struct btrfs_path *path, u64 offset);
 int btrfs_write_out_cache(struct btrfs_root *root,
                           struct btrfs_trans_handle *trans,
                           struct btrfs_block_group_cache *block_group,
                           struct btrfs_path *path);
-
 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
                                     struct btrfs_path *path);
 int create_free_ino_inode(struct btrfs_root *root,