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

Pull btrfs updates from Chris Mason:
 "This is a pretty big pull, and most of these changes have been
  floating in btrfs-next for a long time.  Filipe's properties work is a
  cool building block for inheriting attributes like compression down on
  a per inode basis.

  Jeff Mahoney kicked in code to export filesystem info into sysfs.

  Otherwise, lots of performance improvements, cleanups and bug fixes.

  Looks like there are still a few other small pending incrementals, but
  I wanted to get the bulk of this in first"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (149 commits)
  Btrfs: fix spin_unlock in check_ref_cleanup
  Btrfs: setup inode location during btrfs_init_inode_locked
  Btrfs: don't use ram_bytes for uncompressed inline items
  Btrfs: fix btrfs_search_slot_for_read backwards iteration
  Btrfs: do not export ulist functions
  Btrfs: rework ulist with list+rb_tree
  Btrfs: fix memory leaks on walking backrefs failure
  Btrfs: fix send file hole detection leading to data corruption
  Btrfs: add a reschedule point in btrfs_find_all_roots()
  Btrfs: make send's file extent item search more efficient
  Btrfs: fix to catch all errors when resolving indirect ref
  Btrfs: fix protection between walking backrefs and root deletion
  btrfs: fix warning while merging two adjacent extents
  Btrfs: fix infinite path build loops in incremental send
  btrfs: undo sysfs when open_ctree() fails
  Btrfs: fix snprintf usage by send's gen_unique_name
  btrfs: fix defrag 32-bit integer overflow
  btrfs: sysfs: list the NO_HOLES feature
  btrfs: sysfs: don't show reserved incompat feature
  btrfs: call permission checks earlier in ioctls and return EPERM
  ...

52 files changed, 5103 insertions, 2029 deletions

diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig
index aa976eced2d..a66768ebc8d 100644
--- a/fs/btrfs/Kconfig
+++ b/fs/btrfs/Kconfig
@@ -1,6 +1,7 @@
 config BTRFS_FS
 	tristate "Btrfs filesystem support"
-	select LIBCRC32C
+	select CRYPTO
+	select CRYPTO_CRC32C
 	select ZLIB_INFLATE
 	select ZLIB_DEFLATE
 	select LZO_COMPRESS
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index 1a44e42d602..f341a98031d 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -9,7 +9,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
 	   export.o tree-log.o free-space-cache.o zlib.o lzo.o \
 	   compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \
 	   reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \
-	   uuid-tree.o
+	   uuid-tree.o props.o hash.o
 
 btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
 btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 3775947429b..aded3ef3d3d 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -66,6 +66,16 @@ static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
 	return 0;
 }
 
+static void free_inode_elem_list(struct extent_inode_elem *eie)
+{
+	struct extent_inode_elem *eie_next;
+
+	for (; eie; eie = eie_next) {
+		eie_next = eie->next;
+		kfree(eie);
+	}
+}
+
 static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte,
 				u64 extent_item_pos,
 				struct extent_inode_elem **eie)
@@ -209,18 +219,19 @@ static int __add_prelim_ref(struct list_head *head, u64 root_id,
 }
 
 static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
-				struct ulist *parents, int level,
-				struct btrfs_key *key_for_search, u64 time_seq,
-				u64 wanted_disk_byte,
-				const u64 *extent_item_pos)
+			   struct ulist *parents, struct __prelim_ref *ref,
+			   int level, u64 time_seq, const u64 *extent_item_pos)
 {
 	int ret = 0;
 	int slot;
 	struct extent_buffer *eb;
 	struct btrfs_key key;
+	struct btrfs_key *key_for_search = &ref->key_for_search;
 	struct btrfs_file_extent_item *fi;
 	struct extent_inode_elem *eie = NULL, *old = NULL;
 	u64 disk_byte;
+	u64 wanted_disk_byte = ref->wanted_disk_byte;
+	u64 count = 0;
 
 	if (level != 0) {
 		eb = path->nodes[level];
@@ -238,7 +249,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
 	if (path->slots[0] >= btrfs_header_nritems(path->nodes[0]))
 		ret = btrfs_next_old_leaf(root, path, time_seq);
 
-	while (!ret) {
+	while (!ret && count < ref->count) {
 		eb = path->nodes[0];
 		slot = path->slots[0];
 
@@ -254,6 +265,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
 		if (disk_byte == wanted_disk_byte) {
 			eie = NULL;
 			old = NULL;
+			count++;
 			if (extent_item_pos) {
 				ret = check_extent_in_eb(&key, eb, fi,
 						*extent_item_pos,
@@ -273,6 +285,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
 					old = old->next;
 				old->next = eie;
 			}
+			eie = NULL;
 		}
 next:
 		ret = btrfs_next_old_item(root, path, time_seq);
@@ -280,6 +293,8 @@ next:
 
 	if (ret > 0)
 		ret = 0;
+	else if (ret < 0)
+		free_inode_elem_list(eie);
 	return ret;
 }
 
@@ -299,23 +314,34 @@ static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
 	int ret = 0;
 	int root_level;
 	int level = ref->level;
+	int index;
 
 	root_key.objectid = ref->root_id;
 	root_key.type = BTRFS_ROOT_ITEM_KEY;
 	root_key.offset = (u64)-1;
+
+	index = srcu_read_lock(&fs_info->subvol_srcu);
+
 	root = btrfs_read_fs_root_no_name(fs_info, &root_key);
 	if (IS_ERR(root)) {
+		srcu_read_unlock(&fs_info->subvol_srcu, index);
 		ret = PTR_ERR(root);
 		goto out;
 	}
 
 	root_level = btrfs_old_root_level(root, time_seq);
 
-	if (root_level + 1 == level)
+	if (root_level + 1 == level) {
+		srcu_read_unlock(&fs_info->subvol_srcu, index);
 		goto out;
+	}
 
 	path->lowest_level = level;
 	ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq);
+
+	/* root node has been locked, we can release @subvol_srcu safely here */
+	srcu_read_unlock(&fs_info->subvol_srcu, index);
+
 	pr_debug("search slot in root %llu (level %d, ref count %d) returned "
 		 "%d for key (%llu %u %llu)\n",
 		 ref->root_id, level, ref->count, ret,
@@ -334,9 +360,8 @@ static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
 		eb = path->nodes[level];
 	}
 
-	ret = add_all_parents(root, path, parents, level, &ref->key_for_search,
-				time_seq, ref->wanted_disk_byte,
-				extent_item_pos);
+	ret = add_all_parents(root, path, parents, ref, level, time_seq,
+			      extent_item_pos);
 out:
 	path->lowest_level = 0;
 	btrfs_release_path(path);
@@ -376,10 +401,16 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
 			continue;
 		err = __resolve_indirect_ref(fs_info, path, time_seq, ref,
 					     parents, extent_item_pos);
-		if (err == -ENOMEM)
-			goto out;
-		if (err)
+		/*
+		 * we can only tolerate ENOENT,otherwise,we should catch error
+		 * and return directly.
+		 */
+		if (err == -ENOENT) {
 			continue;
+		} else if (err) {
+			ret = err;
+			goto out;
+		}
 
 		/* we put the first parent into the ref at hand */
 		ULIST_ITER_INIT(&uiter);
@@ -538,14 +569,13 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
 	if (extent_op && extent_op->update_key)
 		btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
 
-	while ((n = rb_prev(n))) {
+	spin_lock(&head->lock);
+	n = rb_first(&head->ref_root);
+	while (n) {
 		struct btrfs_delayed_ref_node *node;
 		node = rb_entry(n, struct btrfs_delayed_ref_node,
 				rb_node);
-		if (node->bytenr != head->node.bytenr)
-			break;
-		WARN_ON(node->is_head);
-
+		n = rb_next(n);
 		if (node->seq > seq)
 			continue;
 
@@ -612,10 +642,10 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
 			WARN_ON(1);
 		}
 		if (ret)
-			return ret;
+			break;
 	}
-
-	return 0;
+	spin_unlock(&head->lock);
+	return ret;
 }
 
 /*
@@ -828,6 +858,7 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
 	struct list_head prefs_delayed;
 	struct list_head prefs;
 	struct __prelim_ref *ref;
+	struct extent_inode_elem *eie = NULL;
 
 	INIT_LIST_HEAD(&prefs);
 	INIT_LIST_HEAD(&prefs_delayed);
@@ -882,15 +913,15 @@ again:
 				btrfs_put_delayed_ref(&head->node);
 				goto again;
 			}
+			spin_unlock(&delayed_refs->lock);
 			ret = __add_delayed_refs(head, time_seq,
 						 &prefs_delayed);
 			mutex_unlock(&head->mutex);
-			if (ret) {
-				spin_unlock(&delayed_refs->lock);
+			if (ret)
 				goto out;
-			}
+		} else {
+			spin_unlock(&delayed_refs->lock);
 		}
-		spin_unlock(&delayed_refs->lock);
 	}
 
 	if (path->slots[0]) {
@@ -941,7 +972,6 @@ again:
 				goto out;
 		}
 		if (ref->count && ref->parent) {
-			struct extent_inode_elem *eie = NULL;
 			if (extent_item_pos && !ref->inode_list) {
 				u32 bsz;
 				struct extent_buffer *eb;
@@ -976,6 +1006,7 @@ again:
 					eie = eie->next;
 				eie->next = ref->inode_list;
 			}
+			eie = NULL;
 		}
 		list_del(&ref->list);
 		kmem_cache_free(btrfs_prelim_ref_cache, ref);
@@ -994,7 +1025,8 @@ out:
 		list_del(&ref->list);
 		kmem_cache_free(btrfs_prelim_ref_cache, ref);
 	}
-
+	if (ret < 0)
+		free_inode_elem_list(eie);
 	return ret;
 }
 
@@ -1002,7 +1034,6 @@ static void free_leaf_list(struct ulist *blocks)
 {
 	struct ulist_node *node = NULL;
 	struct extent_inode_elem *eie;
-	struct extent_inode_elem *eie_next;
 	struct ulist_iterator uiter;
 
 	ULIST_ITER_INIT(&uiter);
@@ -1010,10 +1041,7 @@ static void free_leaf_list(struct ulist *blocks)
 		if (!node->aux)
 			continue;
 		eie = (struct extent_inode_elem *)(uintptr_t)node->aux;
-		for (; eie; eie = eie_next) {
-			eie_next = eie->next;
-			kfree(eie);
-		}
+		free_inode_elem_list(eie);
 		node->aux = 0;
 	}
 
@@ -1101,44 +1129,13 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
 		if (!node)
 			break;
 		bytenr = node->val;
+		cond_resched();
 	}
 
 	ulist_free(tmp);
 	return 0;
 }
 
-
-static int __inode_info(u64 inum, u64 ioff, u8 key_type,
-			struct btrfs_root *fs_root, struct btrfs_path *path,
-			struct btrfs_key *found_key)
-{
-	int ret;
-	struct btrfs_key key;
-	struct extent_buffer *eb;
-
-	key.type = key_type;
-	key.objectid = inum;
-	key.offset = ioff;
-
-	ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
-	if (ret < 0)
-		return ret;
-
-	eb = path->nodes[0];
-	if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
-		ret = btrfs_next_leaf(fs_root, path);
-		if (ret)
-			return ret;
-		eb = path->nodes[0];
-	}
-
-	btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
-	if (found_key->type != key.type || found_key->objectid != key.objectid)
-		return 1;
-
-	return 0;
-}
-
 /*
  * this makes the path point to (inum INODE_ITEM ioff)
  */
@@ -1146,16 +1143,16 @@ int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
 			struct btrfs_path *path)
 {
 	struct btrfs_key key;
-	return __inode_info(inum, ioff, BTRFS_INODE_ITEM_KEY, fs_root, path,
-				&key);
+	return btrfs_find_item(fs_root, path, inum, ioff,
+			BTRFS_INODE_ITEM_KEY, &key);
 }
 
 static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
 				struct btrfs_path *path,
 				struct btrfs_key *found_key)
 {
-	return __inode_info(inum, ioff, BTRFS_INODE_REF_KEY, fs_root, path,
-				found_key);
+	return btrfs_find_item(fs_root, path, inum, ioff,
+			BTRFS_INODE_REF_KEY, found_key);
 }
 
 int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
@@ -1335,20 +1332,45 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
 	ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
 	if (ret < 0)
 		return ret;
-	ret = btrfs_previous_item(fs_info->extent_root, path,
-					0, BTRFS_EXTENT_ITEM_KEY);
-	if (ret < 0)
-		return ret;
 
-	btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
+	while (1) {
+		u32 nritems;
+		if (path->slots[0] == 0) {
+			btrfs_set_path_blocking(path);
+			ret = btrfs_prev_leaf(fs_info->extent_root, path);
+			if (ret != 0) {
+				if (ret > 0) {
+					pr_debug("logical %llu is not within "
+						 "any extent\n", logical);
+					ret = -ENOENT;
+				}
+				return ret;
+			}
+		} else {
+			path->slots[0]--;
+		}
+		nritems = btrfs_header_nritems(path->nodes[0]);
+		if (nritems == 0) {
+			pr_debug("logical %llu is not within any extent\n",
+				 logical);
+			return -ENOENT;
+		}
+		if (path->slots[0] == nritems)
+			path->slots[0]--;
+
+		btrfs_item_key_to_cpu(path->nodes[0], found_key,
+				      path->slots[0]);
+		if (found_key->type == BTRFS_EXTENT_ITEM_KEY ||
+		    found_key->type == BTRFS_METADATA_ITEM_KEY)
+			break;
+	}
+
 	if (found_key->type == BTRFS_METADATA_ITEM_KEY)
 		size = fs_info->extent_root->leafsize;
 	else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
 		size = found_key->offset;
 
-	if ((found_key->type != BTRFS_EXTENT_ITEM_KEY &&
-	     found_key->type != BTRFS_METADATA_ITEM_KEY) ||
-	    found_key->objectid > logical ||
+	if (found_key->objectid > logical ||
 	    found_key->objectid + size <= logical) {
 		pr_debug("logical %llu is not within any extent\n", logical);
 		return -ENOENT;
@@ -1601,7 +1623,6 @@ static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
 	struct btrfs_key found_key;
 
 	while (!ret) {
-		path->leave_spinning = 1;
 		ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path,
 				     &found_key);
 		if (ret < 0)
@@ -1614,9 +1635,12 @@ static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
 
 		parent = found_key.offset;
 		slot = path->slots[0];
-		eb = path->nodes[0];
-		/* make sure we can use eb after releasing the path */
-		atomic_inc(&eb->refs);
+		eb = btrfs_clone_extent_buffer(path->nodes[0]);
+		if (!eb) {
+			ret = -ENOMEM;
+			break;
+		}
+		extent_buffer_get(eb);
 		btrfs_tree_read_lock(eb);
 		btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
 		btrfs_release_path(path);
@@ -1674,17 +1698,20 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
 		++found;
 
 		slot = path->slots[0];
-		eb = path->nodes[0];
-		/* make sure we can use eb after releasing the path */
-		atomic_inc(&eb->refs);
+		eb = btrfs_clone_extent_buffer(path->nodes[0]);
+		if (!eb) {
+			ret = -ENOMEM;
+			break;
+		}
+		extent_buffer_get(eb);
 
 		btrfs_tree_read_lock(eb);
 		btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
 		btrfs_release_path(path);
 
 		leaf = path->nodes[0];
-		item_size = btrfs_item_size_nr(leaf, path->slots[0]);
-		ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
+		item_size = btrfs_item_size_nr(leaf, slot);
+		ptr = btrfs_item_ptr_offset(leaf, slot);
 		cur_offset = 0;
 
 		while (cur_offset < item_size) {
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index ac0b39db27d..8fed2125689 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -43,6 +43,7 @@
 #define BTRFS_INODE_COPY_EVERYTHING		8
 #define BTRFS_INODE_IN_DELALLOC_LIST		9
 #define BTRFS_INODE_READDIO_NEED_LOCK		10
+#define BTRFS_INODE_HAS_PROPS		        11
 
 /* in memory btrfs inode */
 struct btrfs_inode {
@@ -135,6 +136,9 @@ struct btrfs_inode {
 	 */
 	u64 index_cnt;
 
+	/* Cache the directory index number to speed the dir/file remove */
+	u64 dir_index;
+
 	/* the fsync log has some corner cases that mean we have to check
 	 * directories to see if any unlinks have been done before
 	 * the directory was logged.  See tree-log.c for all the
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index cb05e1c842c..49a62b4dda3 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -1456,10 +1456,14 @@ static int btrfsic_handle_extent_data(
 	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
 				     file_extent_item_offset,
 				     sizeof(struct btrfs_file_extent_item));
-	next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item) +
-		      btrfs_stack_file_extent_offset(&file_extent_item);
-	generation = btrfs_stack_file_extent_generation(&file_extent_item);
-	num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
+	next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
+	if (btrfs_stack_file_extent_compression(&file_extent_item) ==
+	    BTRFS_COMPRESS_NONE) {
+		next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
+		num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
+	} else {
+		num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
+	}
 	generation = btrfs_stack_file_extent_generation(&file_extent_item);
 
 	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index f5cdeb4b553..e2600cdb6c2 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -128,11 +128,10 @@ static int check_compressed_csum(struct inode *inode,
 		kunmap_atomic(kaddr);
 
 		if (csum != *cb_sum) {
-			printk(KERN_INFO "btrfs csum failed ino %llu "
-			       "extent %llu csum %u "
-			       "wanted %u mirror %d\n",
-			       btrfs_ino(inode), disk_start, csum, *cb_sum,
-			       cb->mirror_num);
+			btrfs_info(BTRFS_I(inode)->root->fs_info,
+			   "csum failed ino %llu extent %llu csum %u wanted %u mirror %d",
+			   btrfs_ino(inode), disk_start, csum, *cb_sum,
+			   cb->mirror_num);
 			ret = -EIO;
 			goto fail;
 		}
@@ -411,7 +410,8 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start,
 			bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
 		}
 		if (bytes_left < PAGE_CACHE_SIZE) {
-			printk("bytes left %lu compress len %lu nr %lu\n",
+			btrfs_info(BTRFS_I(inode)->root->fs_info,
+					"bytes left %lu compress len %lu nr %lu",
 			       bytes_left, cb->compressed_len, cb->nr_pages);
 		}
 		bytes_left -= PAGE_CACHE_SIZE;
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 316136bd6dd..cbd3a7d6fa6 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -39,9 +39,8 @@ static int balance_node_right(struct btrfs_trans_handle *trans,
 			      struct extent_buffer *src_buf);
 static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
 		    int level, int slot);
-static void tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
+static int tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
 				 struct extent_buffer *eb);
-static int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path);
 
 struct btrfs_path *btrfs_alloc_path(void)
 {
@@ -475,6 +474,8 @@ void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info,
  * the index is the shifted logical of the *new* root node for root replace
  * operations, or the shifted logical of the affected block for all other
  * operations.
+ *
+ * Note: must be called with write lock (tree_mod_log_write_lock).
  */
 static noinline int
 __tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm)
@@ -483,24 +484,9 @@ __tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm)
 	struct rb_node **new;
 	struct rb_node *parent = NULL;
 	struct tree_mod_elem *cur;
-	int ret = 0;
 
 	BUG_ON(!tm);
 
-	tree_mod_log_write_lock(fs_info);
-	if (list_empty(&fs_info->tree_mod_seq_list)) {
-		tree_mod_log_write_unlock(fs_info);
-		/*
-		 * Ok we no longer care about logging modifications, free up tm
-		 * and return 0.  Any callers shouldn't be using tm after
-		 * calling tree_mod_log_insert, but if they do we can just
-		 * change this to return a special error code to let the callers
-		 * do their own thing.
-		 */
-		kfree(tm);
-		return 0;
-	}
-
 	spin_lock(&fs_info->tree_mod_seq_lock);
 	tm->seq = btrfs_inc_tree_mod_seq_minor(fs_info);
 	spin_unlock(&fs_info->tree_mod_seq_lock);
@@ -518,18 +504,13 @@ __tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm)
 			new = &((*new)->rb_left);
 		else if (cur->seq > tm->seq)
 			new = &((*new)->rb_right);
-		else {
-			ret = -EEXIST;
-			kfree(tm);
-			goto out;
-		}
+		else
+			return -EEXIST;
 	}
 
 	rb_link_node(&tm->node, parent, new);
 	rb_insert_color(&tm->node, tm_root);
-out:
-	tree_mod_log_write_unlock(fs_info);
-	return ret;
+	return 0;
 }
 
 /*
@@ -545,19 +526,38 @@ static inline int tree_mod_dont_log(struct btrfs_fs_info *fs_info,
 		return 1;
 	if (eb && btrfs_header_level(eb) == 0)
 		return 1;
+
+	tree_mod_log_write_lock(fs_info);
+	if (list_empty(&(fs_info)->tree_mod_seq_list)) {
+		tree_mod_log_write_unlock(fs_info);
+		return 1;
+	}
+
 	return 0;
 }
 
-static inline int
-__tree_mod_log_insert_key(struct btrfs_fs_info *fs_info,
-			  struct extent_buffer *eb, int slot,
-			  enum mod_log_op op, gfp_t flags)
+/* Similar to tree_mod_dont_log, but doesn't acquire any locks. */
+static inline int tree_mod_need_log(const struct btrfs_fs_info *fs_info,
+				    struct extent_buffer *eb)
+{
+	smp_mb();
+	if (list_empty(&(fs_info)->tree_mod_seq_list))
+		return 0;
+	if (eb && btrfs_header_level(eb) == 0)
+		return 0;
+
+	return 1;
+}
+
+static struct tree_mod_elem *
+alloc_tree_mod_elem(struct extent_buffer *eb, int slot,
+		    enum mod_log_op op, gfp_t flags)
 {
 	struct tree_mod_elem *tm;
 
 	tm = kzalloc(sizeof(*tm), flags);
 	if (!tm)
-		return -ENOMEM;
+		return NULL;
 
 	tm->index = eb->start >> PAGE_CACHE_SHIFT;
 	if (op != MOD_LOG_KEY_ADD) {
@@ -567,8 +567,9 @@ __tree_mod_log_insert_key(struct btrfs_fs_info *fs_info,
 	tm->op = op;
 	tm->slot = slot;
 	tm->generation = btrfs_node_ptr_generation(eb, slot);
+	RB_CLEAR_NODE(&tm->node);
 
-	return __tree_mod_log_insert(fs_info, tm);
+	return tm;
 }
 
 static noinline int
@@ -576,10 +577,27 @@ tree_mod_log_insert_key(struct btrfs_fs_info *fs_info,
 			struct extent_buffer *eb, int slot,
 			enum mod_log_op op, gfp_t flags)
 {
-	if (tree_mod_dont_log(fs_info, eb))
+	struct tree_mod_elem *tm;
+	int ret;
+
+	if (!tree_mod_need_log(fs_info, eb))
 		return 0;