Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (39 commits)
  Btrfs: deal with errors from updating the tree log
  Btrfs: allow subvol deletion by unprivileged user with -o user_subvol_rm_allowed
  Btrfs: make SNAP_DESTROY async
  Btrfs: add SNAP_CREATE_ASYNC ioctl
  Btrfs: add START_SYNC, WAIT_SYNC ioctls
  Btrfs: async transaction commit
  Btrfs: fix deadlock in btrfs_commit_transaction
  Btrfs: fix lockdep warning on clone ioctl
  Btrfs: fix clone ioctl where range is adjacent to extent
  Btrfs: fix delalloc checks in clone ioctl
  Btrfs: drop unused variable in block_alloc_rsv
  Btrfs: cleanup warnings from gcc 4.6 (nonbugs)
  Btrfs: Fix variables set but not read (bugs found by gcc 4.6)
  Btrfs: Use ERR_CAST helpers
  Btrfs: use memdup_user helpers
  Btrfs: fix raid code for removing missing drives
  Btrfs: Switch the extent buffer rbtree into a radix tree
  Btrfs: restructure try_release_extent_buffer()
  Btrfs: use the flusher threads for delalloc throttling
  Btrfs: tune the chunk allocation to 5% of the FS as metadata
  ...

Fix up trivial conflicts in fs/btrfs/super.c and fs/fs-writeback.c, and
remove use of INIT_RCU_HEAD in fs/btrfs/extent_io.c (that init macro was
useless and removed in commit 5e8067ad: "rcu head remove init")

fs/btrfs/compression.c

@@ -163,7 +163,6 @@ static int check_compressed_csum(struct inode *inode,
  */
 static void end_compressed_bio_read(struct bio *bio, int err)
 {
-	struct extent_io_tree *tree;
 	struct compressed_bio *cb = bio->bi_private;
 	struct inode *inode;
 	struct page *page;
@@ -187,7 +186,6 @@ static void end_compressed_bio_read(struct bio *bio, int err)
 	/* ok, we're the last bio for this extent, lets start
 	 * the decompression.
 	 */
-	tree = &BTRFS_I(inode)->io_tree;
 	ret = btrfs_zlib_decompress_biovec(cb->compressed_pages,
 					cb->start,
 					cb->orig_bio->bi_io_vec,

fs/btrfs/ctree.c

@@ -200,7 +200,6 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
 		      struct extent_buffer **cow_ret, u64 new_root_objectid)
 {
 	struct extent_buffer *cow;
-	u32 nritems;
 	int ret = 0;
 	int level;
 	struct btrfs_disk_key disk_key;
@@ -210,7 +209,6 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
 	WARN_ON(root->ref_cows && trans->transid != root->last_trans);
 
 	level = btrfs_header_level(buf);
-	nritems = btrfs_header_nritems(buf);
 	if (level == 0)
 		btrfs_item_key(buf, &disk_key, 0);
 	else
@@ -1008,7 +1006,6 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 	int wret;
 	int pslot;
 	int orig_slot = path->slots[level];
-	int err_on_enospc = 0;
 	u64 orig_ptr;
 
 	if (level == 0)
@@ -1071,8 +1068,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 	    BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
 		return 0;
 
-	if (btrfs_header_nritems(mid) < 2)
-		err_on_enospc = 1;
+	btrfs_header_nritems(mid);
 
 	left = read_node_slot(root, parent, pslot - 1);
 	if (left) {
@@ -1103,8 +1099,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		wret = push_node_left(trans, root, left, mid, 1);
 		if (wret < 0)
 			ret = wret;
-		if (btrfs_header_nritems(mid) < 2)
-			err_on_enospc = 1;
+		btrfs_header_nritems(mid);
 	}
 
 	/*
@@ -1224,14 +1219,12 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
 	int wret;
 	int pslot;
 	int orig_slot = path->slots[level];
-	u64 orig_ptr;
 
 	if (level == 0)
 		return 1;
 
 	mid = path->nodes[level];
 	WARN_ON(btrfs_header_generation(mid) != trans->transid);
-	orig_ptr = btrfs_node_blockptr(mid, orig_slot);
 
 	if (level < BTRFS_MAX_LEVEL - 1)
 		parent = path->nodes[level + 1];
@@ -1577,14 +1570,34 @@ read_block_for_search(struct btrfs_trans_handle *trans,
 	blocksize = btrfs_level_size(root, level - 1);
 
 	tmp = btrfs_find_tree_block(root, blocknr, blocksize);
-	if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
+	if (tmp) {
+		if (btrfs_buffer_uptodate(tmp, 0)) {
+			if (btrfs_buffer_uptodate(tmp, gen)) {
 				/*
-		 * we found an up to date block without sleeping, return
+				 * we found an up to date block without
+				 * sleeping, return
 				 * right away
 				 */
 				*eb_ret = tmp;
 				return 0;
 			}
+			/* the pages were up to date, but we failed
+			 * the generation number check.  Do a full
+			 * read for the generation number that is correct.
+			 * We must do this without dropping locks so
+			 * we can trust our generation number
+			 */
+			free_extent_buffer(tmp);
+			tmp = read_tree_block(root, blocknr, blocksize, gen);
+			if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
+				*eb_ret = tmp;
+				return 0;
+			}
+			free_extent_buffer(tmp);
+			btrfs_release_path(NULL, p);
+			return -EIO;
+		}
+	}
 
 	/*
 	 * reduce lock contention at high levels
@@ -1596,7 +1609,6 @@ read_block_for_search(struct btrfs_trans_handle *trans,
 	btrfs_unlock_up_safe(p, level + 1);
 	btrfs_set_path_blocking(p);
 
-	if (tmp)
 	free_extent_buffer(tmp);
 	if (p->reada)
 		reada_for_search(root, p, level, slot, key->objectid);
@@ -2548,7 +2560,6 @@ static noinline int __push_leaf_left(struct btrfs_trans_handle *trans,
 {
 	struct btrfs_disk_key disk_key;
 	struct extent_buffer *right = path->nodes[0];
-	int slot;
 	int i;
 	int push_space = 0;
 	int push_items = 0;
@@ -2560,8 +2571,6 @@ static noinline int __push_leaf_left(struct btrfs_trans_handle *trans,
 	u32 this_item_size;
 	u32 old_left_item_size;
 
-	slot = path->slots[1];
-
 	if (empty)
 		nr = min(right_nritems, max_slot);
 	else
@@ -3330,7 +3339,6 @@ int btrfs_truncate_item(struct btrfs_trans_handle *trans,
 {
 	int ret = 0;
 	int slot;
-	int slot_orig;
 	struct extent_buffer *leaf;
 	struct btrfs_item *item;
 	u32 nritems;
@@ -3340,7 +3348,6 @@ int btrfs_truncate_item(struct btrfs_trans_handle *trans,
 	unsigned int size_diff;
 	int i;
 
-	slot_orig = path->slots[0];
 	leaf = path->nodes[0];
 	slot = path->slots[0];
 
@@ -3445,7 +3452,6 @@ int btrfs_extend_item(struct btrfs_trans_handle *trans,
 {
 	int ret = 0;
 	int slot;
-	int slot_orig;
 	struct extent_buffer *leaf;
 	struct btrfs_item *item;
 	u32 nritems;
@@ -3454,7 +3460,6 @@ int btrfs_extend_item(struct btrfs_trans_handle *trans,
 	unsigned int old_size;
 	int i;
 
-	slot_orig = path->slots[0];
 	leaf = path->nodes[0];
 
 	nritems = btrfs_header_nritems(leaf);
@@ -3787,7 +3792,6 @@ int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
 			    struct btrfs_key *cpu_key, u32 *data_size,
 			    int nr)
 {
-	struct extent_buffer *leaf;
 	int ret = 0;
 	int slot;
 	int i;
@@ -3804,7 +3808,6 @@ int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
 	if (ret < 0)
 		goto out;
 
-	leaf = path->nodes[0];
 	slot = path->slots[0];
 	BUG_ON(slot < 0);
 

fs/btrfs/ctree.h

@@ -99,6 +99,9 @@ struct btrfs_ordered_sum;
  */
 #define BTRFS_EXTENT_CSUM_OBJECTID -10ULL
 
+/* For storing free space cache */
+#define BTRFS_FREE_SPACE_OBJECTID -11ULL
+
 /* dummy objectid represents multiple objectids */
 #define BTRFS_MULTIPLE_OBJECTIDS -255ULL
 
@@ -265,6 +268,22 @@ struct btrfs_chunk {
 	/* additional stripes go here */
 } __attribute__ ((__packed__));
 
+#define BTRFS_FREE_SPACE_EXTENT	1
+#define BTRFS_FREE_SPACE_BITMAP	2
+
+struct btrfs_free_space_entry {
+	__le64 offset;
+	__le64 bytes;
+	u8 type;
+} __attribute__ ((__packed__));
+
+struct btrfs_free_space_header {
+	struct btrfs_disk_key location;
+	__le64 generation;
+	__le64 num_entries;
+	__le64 num_bitmaps;
+} __attribute__ ((__packed__));
+
 static inline unsigned long btrfs_chunk_item_size(int num_stripes)
 {
 	BUG_ON(num_stripes == 0);
@@ -365,8 +384,10 @@ struct btrfs_super_block {
 
 	char label[BTRFS_LABEL_SIZE];
 
+	__le64 cache_generation;
+
 	/* future expansion */
-	__le64 reserved[32];
+	__le64 reserved[31];
 	u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
 } __attribute__ ((__packed__));
 
@@ -375,13 +396,15 @@ struct btrfs_super_block {
  * ones specified below then we will fail to mount
  */
 #define BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF	(1ULL << 0)
-#define BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL	(2ULL << 0)
+#define BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL	(1ULL << 1)
+#define BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS	(1ULL << 2)
 
 #define BTRFS_FEATURE_COMPAT_SUPP		0ULL
 #define BTRFS_FEATURE_COMPAT_RO_SUPP		0ULL
 #define BTRFS_FEATURE_INCOMPAT_SUPP			\
 	(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF |		\
-	 BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL)
+	 BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |	\
+	 BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
 
 /*
  * A leaf is full of items. offset and size tell us where to find
@@ -675,7 +698,8 @@ struct btrfs_block_group_item {
 struct btrfs_space_info {
 	u64 flags;
 
-	u64 total_bytes;	/* total bytes in the space */
+	u64 total_bytes;	/* total bytes in the space,
+				   this doesn't take mirrors into account */
 	u64 bytes_used;		/* total bytes used,
 				   this does't take mirrors into account */
 	u64 bytes_pinned;	/* total bytes pinned, will be freed when the
@@ -687,6 +711,8 @@ struct btrfs_space_info {
 	u64 bytes_may_use;	/* number of bytes that may be used for
 				   delalloc/allocations */
 	u64 disk_used;		/* total bytes used on disk */
+	u64 disk_total;		/* total bytes on disk, takes mirrors into
+				   account */
 
 	int full;		/* indicates that we cannot allocate any more
 				   chunks for this space */
@@ -750,6 +776,14 @@ enum btrfs_caching_type {
 	BTRFS_CACHE_FINISHED	= 2,
 };
 
+enum btrfs_disk_cache_state {
+	BTRFS_DC_WRITTEN	= 0,
+	BTRFS_DC_ERROR		= 1,
+	BTRFS_DC_CLEAR		= 2,
+	BTRFS_DC_SETUP		= 3,
+	BTRFS_DC_NEED_WRITE	= 4,
+};
+
 struct btrfs_caching_control {
 	struct list_head list;
 	struct mutex mutex;
@@ -763,6 +797,7 @@ struct btrfs_block_group_cache {
 	struct btrfs_key key;
 	struct btrfs_block_group_item item;
 	struct btrfs_fs_info *fs_info;
+	struct inode *inode;
 	spinlock_t lock;
 	u64 pinned;
 	u64 reserved;
@@ -773,8 +808,11 @@ struct btrfs_block_group_cache {
 	int extents_thresh;
 	int free_extents;
 	int total_bitmaps;
-	int ro;
-	int dirty;
+	int ro:1;
+	int dirty:1;
+	int iref:1;
+
+	int disk_cache_state;
 
 	/* cache tracking stuff */
 	int cached;
@@ -863,6 +901,7 @@ struct btrfs_fs_info {
 	struct btrfs_transaction *running_transaction;
 	wait_queue_head_t transaction_throttle;
 	wait_queue_head_t transaction_wait;
+	wait_queue_head_t transaction_blocked_wait;
 	wait_queue_head_t async_submit_wait;
 
 	struct btrfs_super_block super_copy;
@@ -949,6 +988,7 @@ struct btrfs_fs_info {
 	struct btrfs_workers endio_meta_workers;
 	struct btrfs_workers endio_meta_write_workers;
 	struct btrfs_workers endio_write_workers;
+	struct btrfs_workers endio_freespace_worker;
 	struct btrfs_workers submit_workers;
 	/*
 	 * fixup workers take dirty pages that didn't properly go through
@@ -1192,6 +1232,9 @@ struct btrfs_root {
 #define BTRFS_MOUNT_NOSSD		(1 << 9)
 #define BTRFS_MOUNT_DISCARD		(1 << 10)
 #define BTRFS_MOUNT_FORCE_COMPRESS      (1 << 11)
+#define BTRFS_MOUNT_SPACE_CACHE		(1 << 12)
+#define BTRFS_MOUNT_CLEAR_CACHE		(1 << 13)
+#define BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED (1 << 14)
 
 #define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)
 #define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)
@@ -1665,6 +1708,27 @@ static inline void btrfs_set_dir_item_key(struct extent_buffer *eb,
 	write_eb_member(eb, item, struct btrfs_dir_item, location, key);
 }
 
+BTRFS_SETGET_FUNCS(free_space_entries, struct btrfs_free_space_header,
+		   num_entries, 64);
+BTRFS_SETGET_FUNCS(free_space_bitmaps, struct btrfs_free_space_header,
+		   num_bitmaps, 64);
+BTRFS_SETGET_FUNCS(free_space_generation, struct btrfs_free_space_header,
+		   generation, 64);
+
+static inline void btrfs_free_space_key(struct extent_buffer *eb,
+					struct btrfs_free_space_header *h,
+					struct btrfs_disk_key *key)
+{
+	read_eb_member(eb, h, struct btrfs_free_space_header, location, key);
+}
+
+static inline void btrfs_set_free_space_key(struct extent_buffer *eb,
+					    struct btrfs_free_space_header *h,
+					    struct btrfs_disk_key *key)
+{
+	write_eb_member(eb, h, struct btrfs_free_space_header, location, key);
+}
+
 /* struct btrfs_disk_key */
 BTRFS_SETGET_STACK_FUNCS(disk_key_objectid, struct btrfs_disk_key,
 			 objectid, 64);
@@ -1876,6 +1940,8 @@ BTRFS_SETGET_STACK_FUNCS(super_incompat_flags, struct btrfs_super_block,
 			 incompat_flags, 64);
 BTRFS_SETGET_STACK_FUNCS(super_csum_type, struct btrfs_super_block,
 			 csum_type, 16);
+BTRFS_SETGET_STACK_FUNCS(super_cache_generation, struct btrfs_super_block,
+			 cache_generation, 64);
 
 static inline int btrfs_super_csum_size(struct btrfs_super_block *s)
 {
@@ -1988,6 +2054,12 @@ static inline struct dentry *fdentry(struct file *file)
 	return file->f_path.dentry;
 }
 
+static inline bool btrfs_mixed_space_info(struct btrfs_space_info *space_info)
+{
+	return ((space_info->flags & BTRFS_BLOCK_GROUP_METADATA) &&
+		(space_info->flags & BTRFS_BLOCK_GROUP_DATA));
+}
+
 /* extent-tree.c */
 void btrfs_put_block_group(struct btrfs_block_group_cache *cache);
 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
@@ -2079,7 +2151,7 @@ int btrfs_check_data_free_space(struct inode *inode, u64 bytes);
 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes);
 int btrfs_trans_reserve_metadata(struct btrfs_trans_handle *trans,
 				struct btrfs_root *root,
-				int num_items, int *retries);
+				int num_items);
 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
 				struct btrfs_root *root);
 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
@@ -2100,7 +2172,7 @@ void btrfs_add_durable_block_rsv(struct btrfs_fs_info *fs_info,
 int btrfs_block_rsv_add(struct btrfs_trans_handle *trans,
 			struct btrfs_root *root,
 			struct btrfs_block_rsv *block_rsv,
-			u64 num_bytes, int *retries);
+			u64 num_bytes);
 int btrfs_block_rsv_check(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root,
 			  struct btrfs_block_rsv *block_rsv,
@@ -2115,6 +2187,7 @@ int btrfs_set_block_group_ro(struct btrfs_root *root,
 			     struct btrfs_block_group_cache *cache);
 int btrfs_set_block_group_rw(struct btrfs_root *root,
 			     struct btrfs_block_group_cache *cache);
+void btrfs_put_block_group_cache(struct btrfs_fs_info *info);
 /* ctree.c */
 int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
 		     int level, int *slot);
@@ -2373,7 +2446,8 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 			       u32 min_type);
 
 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput);
-int btrfs_start_one_delalloc_inode(struct btrfs_root *root, int delay_iput);
+int btrfs_start_one_delalloc_inode(struct btrfs_root *root, int delay_iput,
+				   int sync);
 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
 			      struct extent_state **cached_state);
 int btrfs_writepages(struct address_space *mapping,
@@ -2426,6 +2500,10 @@ void btrfs_run_delayed_iputs(struct btrfs_root *root);
 int btrfs_prealloc_file_range(struct inode *inode, int mode,
 			      u64 start, u64 num_bytes, u64 min_size,
 			      loff_t actual_len, u64 *alloc_hint);
+int btrfs_prealloc_file_range_trans(struct inode *inode,
+				    struct btrfs_trans_handle *trans, int mode,
+				    u64 start, u64 num_bytes, u64 min_size,
+				    loff_t actual_len, u64 *alloc_hint);
 extern const struct dentry_operations btrfs_dentry_operations;
 
 /* ioctl.c */

fs/btrfs/dir-item.c

@@ -427,5 +427,5 @@ int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 		ret = btrfs_truncate_item(trans, root, path,
 					  item_len - sub_item_len, 1);
 	}
-	return 0;
+	return ret;
 }

fs/btrfs/disk-io.c

@@ -338,7 +338,6 @@ static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 	struct extent_io_tree *tree;
 	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
 	u64 found_start;
-	int found_level;
 	unsigned long len;
 	struct extent_buffer *eb;
 	int ret;
@@ -369,8 +368,6 @@ static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 		WARN_ON(1);
 		goto err;
 	}
-	found_level = btrfs_header_level(eb);
-
 	csum_tree_block(root, eb, 0);
 err:
 	free_extent_buffer(eb);
@@ -481,9 +478,12 @@ static void end_workqueue_bio(struct bio *bio, int err)
 	end_io_wq->work.flags = 0;
 
 	if (bio->bi_rw & REQ_WRITE) {
-		if (end_io_wq->metadata)
+		if (end_io_wq->metadata == 1)
 			btrfs_queue_worker(&fs_info->endio_meta_write_workers,
 					   &end_io_wq->work);
+		else if (end_io_wq->metadata == 2)
+			btrfs_queue_worker(&fs_info->endio_freespace_worker,
+					   &end_io_wq->work);
 		else
 			btrfs_queue_worker(&fs_info->endio_write_workers,
 					   &end_io_wq->work);
@@ -497,6 +497,13 @@ static void end_workqueue_bio(struct bio *bio, int err)
 	}
 }
 
+/*
+ * For the metadata arg you want
+ *
+ * 0 - if data
+ * 1 - if normal metadta
+ * 2 - if writing to the free space cache area
+ */
 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 			int metadata)
 {
@@ -533,11 +540,9 @@ int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
 
 static void run_one_async_start(struct btrfs_work *work)
 {
-	struct btrfs_fs_info *fs_info;
 	struct async_submit_bio *async;
 
 	async = container_of(work, struct  async_submit_bio, work);
-	fs_info = BTRFS_I(async->inode)->root->fs_info;
 	async->submit_bio_start(async->inode, async->rw, async->bio,
 			       async->mirror_num, async->bio_flags,
 			       async->bio_offset);
@@ -850,12 +855,8 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 				      u32 blocksize, u64 parent_transid)
 {
 	struct extent_buffer *buf = NULL;
-	struct inode *btree_inode = root->fs_info->btree_inode;
-	struct extent_io_tree *io_tree;
 	int ret;
 
-	io_tree = &BTRFS_I(btree_inode)->io_tree;
-
 	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 	if (!buf)
 		return NULL;
@@ -1377,7 +1378,6 @@ static int bio_ready_for_csum(struct bio *bio)
 	u64 start = 0;
 	struct page *page;
 	struct extent_io_tree *io_tree = NULL;
-	struct btrfs_fs_info *info = NULL;
 	struct bio_vec *bvec;
 	int i;
 	int ret;
@@ -1396,7 +1396,6 @@ static int bio_ready_for_csum(struct bio *bio)
 		buf_len = page->private >> 2;
 		start = page_offset(page) + bvec->bv_offset;
 		io_tree = &BTRFS_I(page->mapping->host)->io_tree;
-		info = BTRFS_I(page->mapping->host)->root->fs_info;
 	}
 	/* are we fully contained in this bio? */
 	if (buf_len <= length)
@@ -1680,12 +1679,12 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 
 	init_waitqueue_head(&fs_info->transaction_throttle);
 	init_waitqueue_head(&fs_info->transaction_wait);
+	init_waitqueue_head(&fs_info->transaction_blocked_wait);
 	init_waitqueue_head(&fs_info->async_submit_wait);
 
 	__setup_root(4096, 4096, 4096, 4096, tree_root,
 		     fs_info, BTRFS_ROOT_TREE_OBJECTID);
 
-
 	bh = btrfs_read_dev_super(fs_devices->latest_bdev);
 	if (!bh)
 		goto fail_iput;
@@ -1775,6 +1774,8 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
 			   fs_info->thread_pool_size,
 			   &fs_info->generic_worker);
+	btrfs_init_workers(&fs_info->endio_freespace_worker, "freespace-write",
+			   1, &fs_info->generic_worker);
 
 	/*
 	 * endios are largely parallel and should have a very
@@ -1795,6 +1796,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	btrfs_start_workers(&fs_info->endio_meta_workers, 1);
 	btrfs_start_workers(&fs_info->endio_meta_write_workers, 1);
 	btrfs_start_workers(&fs_info->endio_write_workers, 1);
+	btrfs_start_workers(&fs_info->endio_freespace_worker, 1);
 
 	fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
 	fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
@@ -1993,6 +1995,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	if (!(sb->s_flags & MS_RDONLY)) {
 		down_read(&fs_info->cleanup_work_sem);
 		btrfs_orphan_cleanup(fs_info->fs_root);
+		btrfs_orphan_cleanup(fs_info->tree_root);
 		up_read(&fs_info->cleanup_work_sem);
 	}
 
@@ -2035,6 +2038,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	btrfs_stop_workers(&fs_info->endio_meta_workers);
 	btrfs_stop_workers(&fs_info->endio_meta_write_workers);
 	btrfs_stop_workers(&fs_info->endio_write_workers);
+	btrfs_stop_workers(&fs_info->endio_freespace_worker);
 	btrfs_stop_workers(&fs_info->submit_workers);
 fail_iput:
 	invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
@@ -2410,6 +2414,7 @@ int close_ctree(struct btrfs_root *root)
 	fs_info->closing = 1;
 	smp_mb();
 
+	btrfs_put_block_group_cache(fs_info);
 	if (!(fs_info->sb->s_flags & MS_RDONLY)) {
 		ret =  btrfs_commit_super(root);
 		if (ret)
@@ -2456,6 +2461,7 @@ int close_ctree(struct btrfs_root *root)
 	btrfs_stop_workers(&fs_info->endio_meta_workers);
 	btrfs_stop_workers(&fs_info->endio_meta_write_workers);
 	btrfs_stop_workers(&fs_info->endio_write_workers);
+	btrfs_stop_workers(&fs_info->endio_freespace_worker);
 	btrfs_stop_workers(&fs_info->submit_workers);
 
 	btrfs_close_devices(fs_info->fs_devices);

fs/btrfs/extent_io.c

@@ -104,7 +104,7 @@ void extent_io_tree_init(struct extent_io_tree *tree,
 			  struct address_space *mapping, gfp_t mask)
 {
 	tree->state = RB_ROOT;
-	tree->buffer = RB_ROOT;
+	INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
 	tree->ops = NULL;
 	tree->dirty_bytes = 0;
 	spin_lock_init(&tree->lock);
@@ -235,50 +235,6 @@ static inline struct rb_node *tree_search(struct extent_io_tree *tree,
 	return ret;
 }
 
-static struct extent_buffer *buffer_tree_insert(struct extent_io_tree *tree,
-					  u64 offset, struct rb_node *node)
-{
-	struct rb_root *root = &tree->buffer;
-	struct rb_node **p = &root->rb_node;
-	struct rb_node *parent = NULL;
-	struct extent_buffer *eb;
-
-	while (*p) {
-		parent = *p;
-		eb = rb_entry(parent, struct extent_buffer, rb_node);
-
-		if (offset < eb->start)
-			p = &(*p)->rb_left;
-		else if (offset > eb->start)
-			p = &(*p)->rb_right;
-		else
-			return eb;
-	}
-
-	rb_link_node(node, parent, p);
-	rb_insert_color(node, root);
-	return NULL;
-}
-
-static struct extent_buffer *buffer_search(struct extent_io_tree *tree,
-					   u64 offset)
-{
-	struct rb_root *root = &tree->buffer;
-	struct rb_node *n = root->rb_node;
-	struct extent_buffer *eb;
-
-	while (n) {
-		eb = rb_entry(n, struct extent_buffer, rb_node);
-		if (offset < eb->start)
-			n = n->rb_left;
-		else if (offset > eb->start)
-			n = n->rb_right;
-		else
-			return eb;
-	}
-	return NULL;
-}
-
 static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
 		     struct extent_state *other)
 {
@@ -1901,10 +1857,8 @@ static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
 	struct page *page = bvec->bv_page;
 	struct extent_io_tree *tree = bio->bi_private;
 	u64 start;
-	u64 end;
 
 	start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
-	end = start + bvec->bv_len - 1;
 
 	bio->bi_private = NULL;
 
@@ -2204,7 +2158,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 	u64 last_byte = i_size_read(inode);
 	u64 block_start;
 	u64 iosize;
-	u64 unlock_start;
 	sector_t sector;
 	struct extent_state *cached_state = NULL;
 	struct extent_map *em;
@@ -2329,7 +2282,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 		if (tree->ops && tree->ops->writepage_end_io_hook)
 			tree->ops->writepage_end_io_hook(page, start,
 							 page_end, NULL, 1);
-		unlock_start = page_end + 1;
 		goto done;
 	}
 
@@ -2340,7 +2292,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 			if (tree->ops && tree->ops->writepage_end_io_hook)
 				tree->ops->writepage_end_io_hook(page, cur,
 							 page_end, NULL, 1);
-			unlock_start = page_end + 1;
 			break;
 		}
 		em = epd->get_extent(inode, page, pg_offset, cur,
@@ -2387,7 +2338,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 
 			cur += iosize;
 			pg_offset += iosize;
-			unlock_start = cur;
 			continue;
 		}
 		/* leave this out until we have a page_mkwrite call */
@@ -2473,7 +2423,6 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
 	pgoff_t index;
 	pgoff_t end;		/* Inclusive */
 	int scanned = 0;
-	int range_whole = 0;
 
 	pagevec_init(&pvec, 0);
 	if (wbc->range_cyclic) {
@@ -2482,8 +2431,6 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
 	} else {
 		index = wbc->range_start >> PAGE_CACHE_SHIFT;
 		end = wbc->range_end >> PAGE_CACHE_SHIFT;
-		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
-			range_whole = 1;
 		scanned = 1;
 	}
 retry:
@@ -2823,6 +2770,8 @@ int extent_prepare_write(struct extent_io_tree *tree,
 					 NULL, 1,
 					 end_bio_extent_preparewrite, 0,
 					 0, 0);
+			if (ret && !err)
+				err = ret;
 			iocount++;
 			block_start = block_start + iosize;
 		} else {
@@ -3104,6 +3053,39 @@ static void __free_extent_buffer(struct extent_buffer *eb)
 	kmem_cache_free(extent_buffer_cache, eb);
 }
 
+/*
+ * Helper for releasing extent buffer page.
+ */
+static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
+						unsigned long start_idx)
+{
+	unsigned long index;
+	struct page *page;
+
+	if (!eb->first_page)
+		return;
+
+	index = num_extent_pages(eb->start, eb->len);
+	if (start_idx >= index)
+		return;
+
+	do {
+		index--;
+		page = extent_buffer_page(eb, index);
+		if (page)
+			page_cache_release(page);
+	} while (index != start_idx);
+}
+
+/*
+ * Helper for releasing the extent buffer.
+ */
+static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
+{
+	btrfs_release_extent_buffer_page(eb, 0);
+	__free_extent_buffer(eb);
+}
+
 struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
 					  u64 start, unsigned long len,
 					  struct page *page0,
@@ -3117,16 +3099,16 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
 	struct page *p;
 	struct address_space *mapping = tree->mapping;
 	int uptodate = 1;
+	int ret;
 
-	spin_lock(&tree->buffer_lock);
-	eb = buffer_search(tree, start);
-	if (eb) {
-		atomic_inc(&eb->refs);
-		spin_unlock(&tree->buffer_lock);
+	rcu_read_lock();
+	eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
+	if (eb && atomic_inc_not_zero(&eb->refs)) {
+		rcu_read_unlock();
 		mark_page_accessed(eb->first_page);
 		return eb;
 	}
-	spin_unlock(&tree->buffer_lock);
+	rcu_read_unlock();
 
 	eb = __alloc_extent_buffer(tree, start, len, mask);
 	if (!eb)
@@ -3165,26 +3147,31 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
 	if (uptodate)
 		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
 
+	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
+	if (ret)
+		goto free_eb;
+
 	spin_lock(&tree->buffer_lock);
-	exists = buffer_tree_insert(tree, start, &eb->rb_node);
-	if (exists) {
+	ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
+	if (ret == -EEXIST) {
+		exists = radix_tree_lookup(&tree->buffer,
+						start >> PAGE_CACHE_SHIFT);
 		/* add one reference for the caller */
 		atomic_inc(&exists->refs);
 		spin_unlock(&tree->buffer_lock);
+		radix_tree_preload_end();
 		goto free_eb;
 	}
 	/* add one reference for the tree */
 	atomic_inc(&eb->refs);
 	spin_unlock(&tree->buffer_lock);
+	radix_tree_preload_end();
 	return eb;
 
 free_eb:
 	if (!atomic_dec_and_test(&eb->refs))
 		return exists;
-	for (index = 1; index < i; index++)
-		page_cache_release(extent_buffer_page(eb, index));
-	page_cache_release(extent_buffer_page(eb, 0));
-	__free_extent_buffer(eb);
+	btrfs_release_extent_buffer(eb);
 	return exists;
 }
 
@@ -3194,16 +3181,16 @@ struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
 {
 	struct extent_buffer *eb;
 
-	spin_lock(&tree->buffer_lock);
-	eb = buffer_search(tree, start);
-	if (eb)
-		atomic_inc(&eb->refs);
-	spin_unlock(&tree->buffer_lock);
-
-	if (eb)
+	rcu_read_lock();
+	eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
+	if (eb && atomic_inc_not_zero(&eb->refs)) {
+		rcu_read_unlock();
 		mark_page_accessed(eb->first_page);
-
 		return eb;
+	}
+	rcu_read_unlock();
+
+	return NULL;
 }
 
 void free_extent_buffer(struct extent_buffer *eb)
@@ -3833,34 +3820,45 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
 	}
 }
 
+static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
+{
+	struct extent_buffer *eb =
+			container_of(head, struct extent_buffer, rcu_head);
+
+	btrfs_release_extent_buffer(eb);
+}
+
 int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
 {
 	u64 start = page_offset(page);
 	struct extent_buffer *eb;
 	int ret = 1;
-	unsigned long i;
-	unsigned long num_pages;
 
 	spin_lock(&tree->buffer_lock);
-	eb = buffer_search(tree, start);
+	eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
 	if (!eb)
 		goto out;
 
-	if (atomic_read(&eb->refs) > 1) {
+	if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
 		ret = 0;
 		goto out;
 	}
-	if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
+
+	/*
+	 * set @eb->refs to 0 if it is already 1, and then release the @eb.
+	 * Or go back.
+	 */
+	if (atomic_cmpxchg(&eb->refs, 1, 0) != 1) {
 		ret = 0;
 		goto out;
 	}
-	/* at this point we can safely release the extent buffer */
-	num_pages = num_extent_pages(eb->start, eb->len);
-	for (i = 0; i < num_pages; i++)
-		page_cache_release(extent_buffer_page(eb, i));
-	rb_erase(&eb->rb_node, &tree->buffer);
-	__free_extent_buffer(eb);
+
+	radix_tree_delete(&tree->buffer, start >> PAGE_CACHE_SHIFT);
 out:
 	spin_unlock(&tree->buffer_lock);
+
+	/* at this point we can safely release the extent buffer */
+	if (atomic_read(&eb->refs) == 0)
+		call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
 	return ret;
 }

fs/btrfs/extent_io.h

@@ -85,7 +85,7 @@ struct extent_io_ops {
 
 struct extent_io_tree {
 	struct rb_root state;
-	struct rb_root buffer;
+	struct radix_tree_root buffer;
 	struct address_space *mapping;
 	u64 dirty_bytes;
 	spinlock_t lock;
@@ -123,7 +123,7 @@ struct extent_buffer {
 	unsigned long bflags;
 	atomic_t refs;
 	struct list_head leak_list;
-	struct rb_node rb_node;
+	struct rcu_head rcu_head;
 
 	/* the spinlock is used to protect most operations */
 	spinlock_t lock;

fs/btrfs/extent_map.c

@@ -335,7 +335,7 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
 		goto out;
 	}
 	if (IS_ERR(rb_node)) {
-		em = ERR_PTR(PTR_ERR(rb_node));
+		em = ERR_CAST(rb_node);
 		goto out;
 	}
 	em = rb_entry(rb_node, struct extent_map, rb_node);
@@ -384,7 +384,7 @@ struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
 		goto out;
 	}
 	if (IS_ERR(rb_node)) {
-		em = ERR_PTR(PTR_ERR(rb_node));
+		em = ERR_CAST(rb_node);
 		goto out;
 	}
 	em = rb_entry(rb_node, struct extent_map, rb_node);

fs/btrfs/free-space-cache.h

@@ -27,6 +27,24 @@ struct btrfs_free_space {
 	struct list_head list;
 };
 
+struct inode *lookup_free_space_inode(struct btrfs_root *root,
+				      struct btrfs_block_group_cache
+				      *block_group, struct btrfs_path *path);
+int create_free_space_inode(struct btrfs_root *root,
+			    struct btrfs_trans_handle *trans,
+			    struct btrfs_block_group_cache *block_group,
+			    struct btrfs_path *path);
+
+int btrfs_truncate_free_space_cache(struct btrfs_root *root,
+				    struct btrfs_trans_handle *trans,
+				    struct btrfs_path *path,
+				    struct inode *inode);
+int load_free_space_cache(struct btrfs_fs_info *fs_info,
+			  struct btrfs_block_group_cache *block_group);
+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);
 int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
 			 u64 bytenr, u64 size);
 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,

fs/btrfs/ioctl.h

@@ -22,14 +22,21 @@
 
 #define BTRFS_IOCTL_MAGIC 0x94
 #define BTRFS_VOL_NAME_MAX 255
-#define BTRFS_PATH_NAME_MAX 4087
 
 /* this should be 4k */
+#define BTRFS_PATH_NAME_MAX 4087
 struct btrfs_ioctl_vol_args {
 	__s64 fd;
 	char name[BTRFS_PATH_NAME_MAX + 1];
 };
 
+#define BTRFS_SNAPSHOT_NAME_MAX 4079
+struct btrfs_ioctl_async_vol_args {
+	__s64 fd;
+	__u64 transid;
+	char name[BTRFS_SNAPSHOT_NAME_MAX + 1];
+};
+
 #define BTRFS_INO_LOOKUP_PATH_MAX 4080
 struct btrfs_ioctl_ino_lookup_args {
 	__u64 treeid;
@@ -178,4 +185,8 @@ struct btrfs_ioctl_space_args {
 #define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, u64)
 #define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
 				    struct btrfs_ioctl_space_args)
+#define BTRFS_IOC_START_SYNC _IOR(BTRFS_IOCTL_MAGIC, 24, __u64)
+#define BTRFS_IOC_WAIT_SYNC  _IOW(BTRFS_IOCTL_MAGIC, 22, __u64)
+#define BTRFS_IOC_SNAP_CREATE_ASYNC _IOW(BTRFS_IOCTL_MAGIC, 23, \
+				   struct btrfs_ioctl_async_vol_args)
 #endif

fs/btrfs/ordered-data.c

@@ -526,7 +526,6 @@ int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 {
 	u64 end;
 	u64 orig_end;
-	u64 wait_end;
 	struct btrfs_ordered_extent *ordered;
 	int found;
 
@@ -537,7 +536,6 @@ int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 		if (orig_end > INT_LIMIT(loff_t))
 			orig_end = INT_LIMIT(loff_t);
 	}
-	wait_end = orig_end;
 again:
 	/* start IO across the range first to instantiate any delalloc
 	 * extents

fs/btrfs/relocation.c

@@ -29,6 +29,7 @@
 #include "locking.h"
 #include "btrfs_inode.h"
 #include "async-thread.h"
+#include "free-space-cache.h"
 
 /*
  * backref_node, mapping_node and tree_block start with this
@@ -178,8 +179,6 @@ struct reloc_control {
 	u64 search_start;
 	u64 extents_found;
 
-	int block_rsv_retries;
-
 	unsigned int stage:8;
 	unsigned int create_reloc_tree:1;
 	unsigned int merge_reloc_tree:1;
@@ -2133,7 +2132,6 @@ int prepare_to_merge(struct reloc_control *rc, int err)
 	LIST_HEAD(reloc_roots);
 	u64 num_bytes = 0;
 	int ret;
-	int retries = 0;
 
 	mutex_lock(&root->fs_info->trans_mutex);
 	rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
@@ -2143,7 +2141,7 @@ int prepare_to_merge(struct reloc_control *rc, int err)
 	if (!err) {
 		num_bytes = rc->merging_rsv_size;
 		ret = btrfs_block_rsv_add(NULL, root, rc->block_rsv,
-					  num_bytes, &retries);
+					  num_bytes);
 		if (ret)
 			err = ret;
 	}
@@ -2155,7 +2153,6 @@ int prepare_to_merge(struct reloc_control *rc, int err)
 			btrfs_end_transaction(trans, rc->extent_root);
 			btrfs_block_rsv_release(rc->extent_root,
 						rc->block_rsv, num_bytes);
-			retries = 0;
 			goto again;
 		}
 	}
@@ -2405,15 +2402,13 @@ static int reserve_metadata_space(struct btrfs_trans_handle *trans,
 	num_bytes = calcu_metadata_size(rc, node, 1) * 2;
 
 	trans->block_rsv = rc->block_rsv;
-	ret = btrfs_block_rsv_add(trans, root, rc->block_rsv, num_bytes,
-				  &rc->block_rsv_retries);
+	ret = btrfs_block_rsv_add(trans, root, rc->block_rsv, num_bytes);
 	if (ret) {
 		if (ret == -EAGAIN)
 			rc->commit_transaction = 1;
 		return ret;
 	}
 
-	rc->block_rsv_retries = 0;
 	return 0;
 }
 
@@ -3099,6 +3094,8 @@ static int add_tree_block(struct reloc_control *rc,
 		BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
 		ret = get_ref_objectid_v0(rc, path, extent_key,
 					  &ref_owner, NULL);
+		if (ret < 0)
+			return ret;
 		BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
 		level = (int)ref_owner;
 		/* FIXME: get real generation */
@@ -3191,6 +3188,54 @@ static int block_use_full_backref(struct reloc_control *rc,
 	return ret;
 }
 
+static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
+				    struct inode *inode, u64 ino)
+{
+	struct btrfs_key key;
+	struct btrfs_path *path;
+	struct btrfs_root *root = fs_info->tree_root;
+	struct btrfs_trans_handle *trans;
+	unsigned long nr;
+	int ret = 0;
+
+	if (inode)
+		goto truncate;
+
+	key.objectid = ino;
+	key.type = BTRFS_INODE_ITEM_KEY;
+	key.offset = 0;
+
+	inode = btrfs_iget(fs_info->sb, &key, root, NULL);
+	if (!inode || IS_ERR(inode) || is_bad_inode(inode)) {
+		if (inode && !IS_ERR(inode))
+			iput(inode);
+		return -ENOENT;
+	}
+
+truncate:
+	path = btrfs_alloc_path();
+	if (!path) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	trans = btrfs_join_transaction(root, 0);
+	if (IS_ERR(trans)) {
+		btrfs_free_path(path);
+		goto out;
+	}
+
+	ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
+
+	btrfs_free_path(path);
+	nr = trans->blocks_used;
+	btrfs_end_transaction(trans, root);
+	btrfs_btree_balance_dirty(root, nr);
+out:
+	iput(inode);
+	return ret;
+}
+
 /*
  * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
  * this function scans fs tree to find blocks reference the data extent
@@ -3217,15 +3262,27 @@ static int find_data_references(struct reloc_control *rc,
 	int counted;
 	int ret;
 
-	path = btrfs_alloc_path();
-	if (!path)
-		return -ENOMEM;
-
 	ref_root = btrfs_extent_data_ref_root(leaf, ref);
 	ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
 	ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
 	ref_count = btrfs_extent_data_ref_count(leaf, ref);
 
+	/*
+	 * This is an extent belonging to the free space cache, lets just delete
+	 * it and redo the search.
+	 */
+	if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
+		ret = delete_block_group_cache(rc->extent_root->fs_info,
+					       NULL, ref_objectid);
+		if (ret != -ENOENT)
+			return ret;
+		ret = 0;
+	}
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
 	root = read_fs_root(rc->extent_root->fs_info, ref_root);
 	if (IS_ERR(root)) {
 		err = PTR_ERR(root);
@@ -3554,8 +3611,7 @@ int prepare_to_relocate(struct reloc_control *rc)
 	 * is no reservation in transaction handle.
 	 */
 	ret = btrfs_block_rsv_add(NULL, rc->extent_root, rc->block_rsv,
-				  rc->extent_root->nodesize * 256,
-				  &rc->block_rsv_retries);
+				  rc->extent_root->nodesize * 256);
 	if (ret)
 		return ret;
 
@@ -3567,7 +3623,6 @@ int prepare_to_relocate(struct reloc_control *rc)
 	rc->extents_found = 0;
 	rc->nodes_relocated = 0;
 	rc->merging_rsv_size = 0;
-	rc->block_rsv_retries = 0;
 
 	rc->create_reloc_tree = 1;
 	set_reloc_control(rc);
@@ -3860,6 +3915,8 @@ int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
 {
 	struct btrfs_fs_info *fs_info = extent_root->fs_info;
 	struct reloc_control *rc;
+	struct inode *inode;
+	struct btrfs_path *path;
 	int ret;
 	int rw = 0;
 	int err = 0;
@@ -3882,6 +3939,26 @@ int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
 		rw = 1;
 	}
 
+	path = btrfs_alloc_path();
+	if (!path) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
+					path);
+	btrfs_free_path(path);
+
+	if (!IS_ERR(inode))
+		ret = delete_block_group_cache(fs_info, inode, 0);
+	else
+		ret = PTR_ERR(inode);
+
+	if (ret && ret != -ENOENT) {
+		err = ret;
+		goto out;
+	}
+
 	rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
 	if (IS_ERR(rc->data_inode)) {
 		err = PTR_ERR(rc->data_inode);
@@ -4143,7 +4220,7 @@ int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
 		btrfs_add_ordered_sum(inode, ordered, sums);
 	}
 	btrfs_put_ordered_extent(ordered);
-	return 0;
+	return ret;
 }
 
 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,

fs/btrfs/root-tree.c

@@ -181,7 +181,6 @@ int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
 int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid)
 {
 	struct btrfs_root *dead_root;
-	struct btrfs_item *item;
 	struct btrfs_root_item *ri;
 	struct btrfs_key key;
 	struct btrfs_key found_key;
@@ -214,7 +213,6 @@ int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid)
 			nritems = btrfs_header_nritems(leaf);
 			slot = path->slots[0];
 		}
-		item = btrfs_item_nr(leaf, slot);
 		btrfs_item_key_to_cpu(leaf, &key, slot);
 		if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
 			goto next;

fs/btrfs/super.c

@@ -61,6 +61,8 @@ static void btrfs_put_super(struct super_block *sb)
 
 	ret = close_ctree(root);
 	sb->s_fs_info = NULL;
+
+	(void)ret; /* FIXME: need to fix VFS to return error? */
 }
 
 enum {
@@ -68,7 +70,8 @@ enum {
 	Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 	Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 	Opt_compress_force, Opt_notreelog, Opt_ratio, Opt_flushoncommit,
-	Opt_discard, Opt_err,
+	Opt_discard, Opt_space_cache, Opt_clear_cache, Opt_err,
+	Opt_user_subvol_rm_allowed,
 };
 
 static match_table_t tokens = {
@@ -92,6 +95,9 @@ static match_table_t tokens = {
 	{Opt_flushoncommit, "flushoncommit"},
 	{Opt_ratio, "metadata_ratio=%d"},
 	{Opt_discard, "discard"},
+	{Opt_space_cache, "space_cache"},
+	{Opt_clear_cache, "clear_cache"},
+	{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 	{Opt_err, NULL},
 };
 
@@ -235,6 +241,16 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
 		case Opt_discard:
 			btrfs_set_opt(info->mount_opt, DISCARD);
 			break;
+		case Opt_space_cache:
+			printk(KERN_INFO "btrfs: enabling disk space caching\n");
+			btrfs_set_opt(info->mount_opt, SPACE_CACHE);
+		case Opt_clear_cache:
+			printk(KERN_INFO "btrfs: force clearing of disk cache\n");
+			btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
+			break;
+		case Opt_user_subvol_rm_allowed:
+			btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
+			break;
 		case Opt_err:
 			printk(KERN_INFO "btrfs: unrecognized mount option "
 			       "'%s'\n", p);
@@ -380,7 +396,7 @@ static struct dentry *get_default_root(struct super_block *sb,
 find_root:
 	new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
 	if (IS_ERR(new_root))
-		return ERR_PTR(PTR_ERR(new_root));
+		return ERR_CAST(new_root);
 
 	if (btrfs_root_refs(&new_root->root_item) == 0)
 		return ERR_PTR(-ENOENT);
@@ -436,7 +452,6 @@ static int btrfs_fill_super(struct super_block *sb,
 {
 	struct inode *inode;
 	struct dentry *root_dentry;
-	struct btrfs_super_block *disk_super;
 	struct btrfs_root *tree_root;
 	struct btrfs_key key;
 	int err;
@@ -458,7 +473,6 @@ static int btrfs_fill_super(struct super_block *sb,
 		return PTR_ERR(tree_root);
 	}
 	sb->s_fs_info = tree_root;
-	disk_super = &tree_root->fs_info->super_copy;
 
 	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 	key.type = BTRFS_INODE_ITEM_KEY;
@@ -571,7 +585,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 	char *subvol_name = NULL;
 	u64 subvol_objectid = 0;
 	int error = 0;
-	int found = 0;
 
 	if (!(flags & MS_RDONLY))
 		mode |= FMODE_WRITE;
@@ -607,7 +620,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 			goto error_close_devices;
 		}
 
-		found = 1;
 		btrfs_close_devices(fs_devices);
 	} else {
 		char b[BDEVNAME_SIZE];
@@ -629,7 +641,7 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 	if (IS_ERR(root)) {
 		error = PTR_ERR(root);
 		deactivate_locked_super(s);
-		goto error;
+		goto error_free_subvol_name;
 	}
 	/* if they gave us a subvolume name bind mount into that */
 	if (strcmp(subvol_name, ".")) {
@@ -643,14 +655,14 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 			deactivate_locked_super(s);
 			error = PTR_ERR(new_root);
 			dput(root);
-			goto error_close_devices;
+			goto error_free_subvol_name;
 		}
 		if (!new_root->d_inode) {
 			dput(root);
 			dput(new_root);
 			deactivate_locked_super(s);
 			error = -ENXIO;
-			goto error_close_devices;
+			goto error_free_subvol_name;
 		}
 		dput(root);
 		root = new_root;
@@ -665,7 +677,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 	btrfs_close_devices(fs_devices);
 error_free_subvol_name:
 	kfree(subvol_name);
-error:
 	return ERR_PTR(error);
 }
 
@@ -713,18 +724,25 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	struct list_head *head = &root->fs_info->space_info;
 	struct btrfs_space_info *found;
 	u64 total_used = 0;
+	u64 total_used_data = 0;
 	int bits = dentry->d_sb->s_blocksize_bits;
 	__be32 *fsid = (__be32 *)root->fs_info->fsid;
 
 	rcu_read_lock();
-	list_for_each_entry_rcu(found, head, list)
+	list_for_each_entry_rcu(found, head, list) {
+		if (found->flags & (BTRFS_BLOCK_GROUP_METADATA |
+				    BTRFS_BLOCK_GROUP_SYSTEM))
+			total_used_data += found->disk_total;
+		else
+			total_used_data += found->disk_used;
 		total_used += found->disk_used;
+	}
 	rcu_read_unlock();
 
 	buf->f_namelen = BTRFS_NAME_LEN;
 	buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
 	buf->f_bfree = buf->f_blocks - (total_used >> bits);
-	buf->f_bavail = buf->f_bfree;
+	buf->f_bavail = buf->f_blocks - (total_used_data >> bits);
 	buf->f_bsize = dentry->d_sb->s_blocksize;
 	buf->f_type = BTRFS_SUPER_MAGIC;
 

fs/btrfs/transaction.h

@@ -87,12 +87,17 @@ static inline void btrfs_set_inode_last_trans(struct btrfs_trans_handle *trans,
 
 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root);
+int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
+				 struct btrfs_root *root);
 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 						   int num_items);
 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
 						  int num_blocks);
+struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root,
+							  int num_blocks);
 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
 							 int num_blocks);
+int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid);
 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
 				     struct btrfs_root *root);
 int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
@@ -104,6 +109,9 @@ int btrfs_defrag_root(struct btrfs_root *root, int cacheonly);
 int btrfs_clean_old_snapshots(struct btrfs_root *root);
 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *root);
+int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
+				   struct btrfs_root *root,
+				   int wait_for_unblock);
 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
 				   struct btrfs_root *root);
 int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,

fs/btrfs/tree-defrag.c

@@ -36,7 +36,6 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
 	int ret = 0;
 	int wret;
 	int level;
-	int orig_level;
 	int is_extent = 0;
 	int next_key_ret = 0;
 	u64 last_ret = 0;
@@ -64,7 +63,6 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
 		return -ENOMEM;
 
 	level = btrfs_header_level(root->node);
-	orig_level = level;
 
 	if (level == 0)
 		goto out;

fs/btrfs/tree-log.c

@@ -786,7 +786,6 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 {
 	struct inode *dir;
 	int ret;
-	struct btrfs_key location;
 	struct btrfs_inode_ref *ref;
 	struct btrfs_dir_item *di;
 	struct inode *inode;
@@ -795,10 +794,6 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 	unsigned long ref_ptr;
 	unsigned long ref_end;
 
-	location.objectid = key->objectid;
-	location.type = BTRFS_INODE_ITEM_KEY;
-	location.offset = 0;
-
 	/*
 	 * it is possible that we didn't log all the parent directories
 	 * for a given inode.  If we don't find the dir, just don't
@@ -1583,7 +1578,6 @@ static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb,
 	struct btrfs_path *path;
 	struct btrfs_root *root = wc->replay_dest;
 	struct btrfs_key key;
-	u32 item_size;
 	int level;
 	int i;
 	int ret;
@@ -1601,7 +1595,6 @@ static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb,
 	nritems = btrfs_header_nritems(eb);
 	for (i = 0; i < nritems; i++) {
 		btrfs_item_key_to_cpu(eb, &key, i);
-		item_size = btrfs_item_size_nr(eb, i);
 
 		/* inode keys are done during the first stage */
 		if (key.type == BTRFS_INODE_ITEM_KEY &&
@@ -1668,7 +1661,6 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
 				   struct walk_control *wc)
 {
 	u64 root_owner;
-	u64 root_gen;
 	u64 bytenr;
 	u64 ptr_gen;
 	struct extent_buffer *next;
@@ -1698,7 +1690,6 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
 
 		parent = path->nodes[*level];
 		root_owner = btrfs_header_owner(parent);
-		root_gen = btrfs_header_generation(parent);
 
 		next = btrfs_find_create_tree_block(root, bytenr, blocksize);
 
@@ -1749,7 +1740,6 @@ static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
 				 struct walk_control *wc)
 {
 	u64 root_owner;
-	u64 root_gen;
 	int i;
 	int slot;
 	int ret;
@@ -1757,8 +1747,6 @@ static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
 	for (i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
 		slot = path->slots[i];
 		if (slot + 1 < btrfs_header_nritems(path->nodes[i])) {
-			struct extent_buffer *node;
-			node = path->nodes[i];
 			path->slots[i]++;
 			*level = i;
 			WARN_ON(*level == 0);
@@ -1771,7 +1759,6 @@ static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
 				parent = path->nodes[*level + 1];
 
 			root_owner = btrfs_header_owner(parent);
-			root_gen = btrfs_header_generation(parent);
 			wc->process_func(root, path->nodes[*level], wc,
 				 btrfs_header_generation(path->nodes[*level]));
 			if (wc->free) {
@@ -2273,7 +2260,7 @@ int btrfs_del_dir_entries_in_log(struct btrfs_trans_handle *trans,
 	}
 	btrfs_end_log_trans(root);
 
-	return 0;
+	return err;
 }
 
 /* see comments for btrfs_del_dir_entries_in_log */
@@ -2729,7 +2716,6 @@ static int btrfs_log_inode(struct btrfs_trans_handle *trans,
 	struct btrfs_key max_key;
 	struct btrfs_root *log = root->log_root;
 	struct extent_buffer *src = NULL;
-	u32 size;
 	int err = 0;
 	int ret;
 	int nritems;
@@ -2793,7 +2779,6 @@ static int btrfs_log_inode(struct btrfs_trans_handle *trans,
 			break;
 
 		src = path->nodes[0];
-		size = btrfs_item_size_nr(src, path->slots[0]);
 		if (ins_nr && ins_start_slot + ins_nr == path->slots[0]) {
 			ins_nr++;
 			goto next_slot;

fs/btrfs/volumes.c

@@ -1898,7 +1898,6 @@ int btrfs_balance(struct btrfs_root *dev_root)
 	u64 size_to_free;
 	struct btrfs_path *path;
 	struct btrfs_key key;
-	struct btrfs_chunk *chunk;
 	struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
 	struct btrfs_trans_handle *trans;
 	struct btrfs_key found_key;
@@ -1962,9 +1961,6 @@ int btrfs_balance(struct btrfs_root *dev_root)
 		if (found_key.objectid != key.objectid)
 			break;
 
-		chunk = btrfs_item_ptr(path->nodes[0],
-				       path->slots[0],
-				       struct btrfs_chunk);
 		/* chunk zero is special */
 		if (found_key.offset == 0)
 			break;
@@ -3031,8 +3027,7 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 		}
 		bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
 		dev = multi->stripes[dev_nr].dev;
-		BUG_ON(rw == WRITE && !dev->writeable);
-		if (dev && dev->bdev) {
+		if (dev && dev->bdev && (rw != WRITE || dev->writeable)) {
 			bio->bi_bdev = dev->bdev;
 			if (async_submit)
 				schedule_bio(root, dev, rw, bio);

fs/btrfs/xattr.c

@@ -178,7 +178,6 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 	struct inode *inode = dentry->d_inode;
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 	struct btrfs_path *path;
-	struct btrfs_item *item;
 	struct extent_buffer *leaf;
 	struct btrfs_dir_item *di;
 	int ret = 0, slot, advance;
@@ -234,7 +233,6 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 		}
 		advance = 1;
 
-		item = btrfs_item_nr(leaf, slot);
 		btrfs_item_key_to_cpu(leaf, &found_key, slot);
 
 		/* check to make sure this item is what we want */

fs/btrfs/zlib.c

@@ -199,8 +199,6 @@ int btrfs_zlib_compress_pages(struct address_space *mapping,
 	int nr_pages = 0;
 	struct page *in_page = NULL;
 	struct page *out_page = NULL;
-	int out_written = 0;
-	int in_read = 0;
 	unsigned long bytes_left;
 
 	*out_pages = 0;
@@ -233,9 +231,6 @@ int btrfs_zlib_compress_pages(struct address_space *mapping,
 	workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
 	workspace->def_strm.avail_in = min(len, PAGE_CACHE_SIZE);
 
-	out_written = 0;
-	in_read = 0;
-
 	while (workspace->def_strm.total_in < len) {
 		ret = zlib_deflate(&workspace->def_strm, Z_SYNC_FLUSH);
 		if (ret != Z_OK) {

fs/fs-writeback.c

@@ -1081,30 +1081,42 @@ static void wait_sb_inodes(struct super_block *sb)
 }
 
 /**
- * writeback_inodes_sb	-	writeback dirty inodes from given super_block
+ * writeback_inodes_sb_nr -	writeback dirty inodes from given super_block
  * @sb: the superblock
+ * @nr: the number of pages to write
  *
  * Start writeback on some inodes on this super_block. No guarantees are made
  * on how many (if any) will be written, and this function does not wait
- * for IO completion of submitted IO. The number of pages submitted is
- * returned.
+ * for IO completion of submitted IO.
  */
-void writeback_inodes_sb(struct super_block *sb)
+void writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr)
 {
 	DECLARE_COMPLETION_ONSTACK(done);
 	struct wb_writeback_work work = {
 		.sb		= sb,
 		.sync_mode	= WB_SYNC_NONE,
 		.done		= &done,
+		.nr_pages	= nr,
 	};
 
 	WARN_ON(!rwsem_is_locked(&sb->s_umount));
-
-	work.nr_pages = get_nr_dirty_pages();
-
 	bdi_queue_work(sb->s_bdi, &work);
 	wait_for_completion(&done);
 }
+EXPORT_SYMBOL(writeback_inodes_sb_nr);
+
+/**
+ * writeback_inodes_sb	-	writeback dirty inodes from given super_block
+ * @sb: the superblock
+ *
+ * Start writeback on some inodes on this super_block. No guarantees are made
+ * on how many (if any) will be written, and this function does not wait
+ * for IO completion of submitted IO.
+ */
+void writeback_inodes_sb(struct super_block *sb)
+{
+	return writeback_inodes_sb_nr(sb, get_nr_dirty_pages());
+}
 EXPORT_SYMBOL(writeback_inodes_sb);
 
 /**
@@ -1126,6 +1138,27 @@ int writeback_inodes_sb_if_idle(struct super_block *sb)
 }
 EXPORT_SYMBOL(writeback_inodes_sb_if_idle);
 
+/**
+ * writeback_inodes_sb_if_idle	-	start writeback if none underway
+ * @sb: the superblock
+ * @nr: the number of pages to write
+ *
+ * Invoke writeback_inodes_sb if no writeback is currently underway.
+ * Returns 1 if writeback was started, 0 if not.
+ */
+int writeback_inodes_sb_nr_if_idle(struct super_block *sb,
+				   unsigned long nr)
+{
+	if (!writeback_in_progress(sb->s_bdi)) {
+		down_read(&sb->s_umount);
+		writeback_inodes_sb_nr(sb, nr);
+		up_read(&sb->s_umount);
+		return 1;
+	} else
+		return 0;
+}
+EXPORT_SYMBOL(writeback_inodes_sb_nr_if_idle);
+
 /**
  * sync_inodes_sb	-	sync sb inode pages
  * @sb: the superblock

include/linux/writeback.h

@@ -58,7 +58,9 @@ struct writeback_control {
 struct bdi_writeback;
 int inode_wait(void *);
 void writeback_inodes_sb(struct super_block *);
+void writeback_inodes_sb_nr(struct super_block *, unsigned long nr);
 int writeback_inodes_sb_if_idle(struct super_block *);
+int writeback_inodes_sb_nr_if_idle(struct super_block *, unsigned long nr);
 void sync_inodes_sb(struct super_block *);
 void writeback_inodes_wb(struct bdi_writeback *wb,
 		struct writeback_control *wbc);