diff --git a/kernel-shared/compression.h b/kernel-shared/compression.h
index e3f58dd6..788ab75d 100644
--- a/kernel-shared/compression.h
+++ b/kernel-shared/compression.h
@@ -7,8 +7,10 @@
 #define BTRFS_COMPRESSION_H
 
 #include "kerncompat.h"
+#include "kernel-lib/sizes.h"
 
 struct btrfs_inode;
+struct btrfs_ordered_extent;
 struct address_space;
 struct inode;
 struct bio;
@@ -27,12 +29,16 @@ struct btrfs_bio { };
 
 /* Maximum length of compressed data stored on disk */
 #define BTRFS_MAX_COMPRESSED		(SZ_128K)
+#define BTRFS_MAX_COMPRESSED_PAGES	(BTRFS_MAX_COMPRESSED / PAGE_SIZE)
+_static_assert((BTRFS_MAX_COMPRESSED % PAGE_SIZE) == 0);
 
 /* Maximum size of data before compression */
 #define BTRFS_MAX_UNCOMPRESSED		(SZ_128K)
 
 #define	BTRFS_ZLIB_DEFAULT_LEVEL		3
 
+struct page;
+
 struct compressed_bio {
 	/* Number of compressed pages in the array */
 	unsigned int nr_pages;
@@ -88,17 +94,18 @@ int btrfs_decompress(int type, const u8 *data_in, struct page *dest_page,
 int btrfs_decompress_buf2page(const char *buf, u32 buf_len,
 			      struct compressed_bio *cb, u32 decompressed);
 
-void btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
-				  unsigned int len, u64 disk_start,
-				  unsigned int compressed_len,
+void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered,
 				  struct page **compressed_pages,
 				  unsigned int nr_pages,
 				  blk_opf_t write_flags,
 				  bool writeback);
-void btrfs_submit_compressed_read(struct btrfs_bio *bbio, int mirror_num);
+void btrfs_submit_compressed_read(struct btrfs_bio *bbio);
 
 unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
 
+struct page *btrfs_alloc_compr_page(void);
+void btrfs_free_compr_page(struct page *page);
+
 enum btrfs_compression_type {
 	BTRFS_COMPRESS_NONE  = 0,
 	BTRFS_COMPRESS_ZLIB  = 1,
@@ -146,7 +153,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
 		unsigned long *total_in, unsigned long *total_out);
 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 int zlib_decompress(struct list_head *ws, const u8 *data_in,
-		struct page *dest_page, unsigned long start_byte, size_t srclen,
+		struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
 		size_t destlen);
 struct list_head *zlib_alloc_workspace(unsigned int level);
 void zlib_free_workspace(struct list_head *ws);
@@ -157,7 +164,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
 		unsigned long *total_in, unsigned long *total_out);
 int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 int lzo_decompress(struct list_head *ws, const u8 *data_in,
-		struct page *dest_page, unsigned long start_byte, size_t srclen,
+		struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
 		size_t destlen);
 struct list_head *lzo_alloc_workspace(unsigned int level);
 void lzo_free_workspace(struct list_head *ws);
diff --git a/kernel-shared/ctree.h b/kernel-shared/ctree.h
index 94463222..444d206e 100644
--- a/kernel-shared/ctree.h
+++ b/kernel-shared/ctree.h
@@ -1219,7 +1219,7 @@ static inline int is_fstree(u64 rootid)
 	return 0;
 }
 
-void btrfs_uuid_to_key(const u8 *uuid, struct btrfs_key *key);
+void btrfs_uuid_to_key(const u8 *uuid, u8 type, struct btrfs_key *key);
 
 /* inode.c */
 int check_dir_conflict(struct btrfs_root *root, char *name, int namelen,
diff --git a/kernel-shared/delayed-ref.h b/kernel-shared/delayed-ref.h
index bb3a771a..95bf62ab 100644
--- a/kernel-shared/delayed-ref.h
+++ b/kernel-shared/delayed-ref.h
@@ -32,10 +32,16 @@ struct btrfs_trans_handle;
 struct btrfs_block_rsv;
 
 /* these are the possible values of struct btrfs_delayed_ref_node->action */
-#define BTRFS_ADD_DELAYED_REF    1 /* add one backref to the tree */
-#define BTRFS_DROP_DELAYED_REF   2 /* delete one backref from the tree */
-#define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */
-#define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */
+enum btrfs_delayed_ref_action {
+	/* Add one backref to the tree */
+	BTRFS_ADD_DELAYED_REF = 1,
+	/* Delete one backref from the tree */
+	BTRFS_DROP_DELAYED_REF,
+	/* Record a full extent allocation */
+	BTRFS_ADD_DELAYED_EXTENT,
+	/* Not changing ref count on head ref */
+	BTRFS_UPDATE_DELAYED_HEAD,
+} __attribute__ ((__packed__));
 
 struct btrfs_delayed_ref_node {
 	struct rb_node ref_node;
@@ -210,7 +216,7 @@ enum btrfs_ref_type {
 	BTRFS_REF_DATA,
 	BTRFS_REF_METADATA,
 	BTRFS_REF_LAST,
-};
+} __attribute__((__packed__));
 
 struct btrfs_data_ref {
 	/* For EXTENT_DATA_REF */
@@ -250,7 +256,7 @@ struct btrfs_tree_ref {
 
 struct btrfs_ref {
 	enum btrfs_ref_type type;
-	int action;
+	enum btrfs_delayed_ref_action action;
 
 	/*
 	 * Whether this extent should go through qgroup record.
diff --git a/kernel-shared/free-space-tree.c b/kernel-shared/free-space-tree.c
index e31854ce..93806ca0 100644
--- a/kernel-shared/free-space-tree.c
+++ b/kernel-shared/free-space-tree.c
@@ -178,9 +178,10 @@ out:
 	return ret;
 }
 
-static inline u32 free_space_bitmap_size(u64 size, u32 sectorsize)
+static inline u32 free_space_bitmap_size(const struct btrfs_fs_info *fs_info,
+					 u64 size)
 {
-	return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE);
+	return DIV_ROUND_UP((u32)div_u64(size, fs_info->sectorsize), BITS_PER_BYTE);
 }
 
 static unsigned long *alloc_bitmap(u32 bitmap_size)
@@ -241,8 +242,7 @@ static int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
 	int done = 0, nr;
 	int ret;
 
-	bitmap_size = free_space_bitmap_size(block_group->length,
-					     fs_info->sectorsize);
+	bitmap_size = free_space_bitmap_size(fs_info, block_group->length);
 	bitmap = alloc_bitmap(bitmap_size);
 	if (!bitmap) {
 		ret = -ENOMEM;
@@ -331,8 +331,7 @@ static int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
 		u32 data_size;
 
 		extent_size = min(end - i, bitmap_range);
-		data_size = free_space_bitmap_size(extent_size,
-						   fs_info->sectorsize);
+		data_size = free_space_bitmap_size(fs_info, extent_size);
 
 		key.objectid = i;
 		key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
@@ -379,8 +378,7 @@ static int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
 	int done = 0, nr;
 	int ret;
 
-	bitmap_size = free_space_bitmap_size(block_group->start,
-					     fs_info->sectorsize);
+	bitmap_size = free_space_bitmap_size(fs_info, block_group->length);
 	bitmap = alloc_bitmap(bitmap_size);
 	if (!bitmap) {
 		ret = -ENOMEM;
@@ -423,8 +421,8 @@ static int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
 						     fs_info->sectorsize *
 						     BITS_PER_BYTE);
 				bitmap_cursor = ((char *)bitmap) + bitmap_pos;
-				data_size = free_space_bitmap_size(found_key.offset,
-								   fs_info->sectorsize);
+				data_size = free_space_bitmap_size(fs_info,
+								found_key.offset);
 
 				ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
 				read_extent_buffer(leaf, bitmap_cursor, ptr,
diff --git a/kernel-shared/free-space-tree.h b/kernel-shared/free-space-tree.h
index a93ebe21..ec0539c4 100644
--- a/kernel-shared/free-space-tree.h
+++ b/kernel-shared/free-space-tree.h
@@ -26,6 +26,11 @@ struct btrfs_block_group;
 struct btrfs_fs_info;
 struct btrfs_trans_handle;
 
+/*
+ * The default size for new free space bitmap items. The last bitmap in a block
+ * group may be truncated, and none of the free space tree code assumes that
+ * existing bitmaps are this size.
+ */
 #define BTRFS_FREE_SPACE_BITMAP_SIZE 256
 #define BTRFS_FREE_SPACE_BITMAP_BITS (BTRFS_FREE_SPACE_BITMAP_SIZE * BITS_PER_BYTE)
 
diff --git a/kernel-shared/inode-item.c b/kernel-shared/inode-item.c
index 260d86b7..f3f7286b 100644
--- a/kernel-shared/inode-item.c
+++ b/kernel-shared/inode-item.c
@@ -29,10 +29,9 @@
 
 struct btrfs_trans_handle;
 
-static int find_name_in_backref(struct btrfs_path *path, const char * name,
-			 int name_len, struct btrfs_inode_ref **ref_ret)
+static int find_name_in_backref(struct extent_buffer *leaf, int slot, const char * name,
+				int name_len, struct btrfs_inode_ref **ref_ret)
 {
-	struct extent_buffer *leaf;
 	struct btrfs_inode_ref *ref;
 	unsigned long ptr;
 	unsigned long name_ptr;
@@ -40,9 +39,8 @@ static int find_name_in_backref(struct btrfs_path *path, const char * name,
 	u32 cur_offset = 0;
 	int len;
 
-	leaf = path->nodes[0];
-	item_size = btrfs_item_size(leaf, path->slots[0]);
-	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
+	item_size = btrfs_item_size(leaf, slot);
+	ptr = btrfs_item_ptr_offset(leaf, slot);
 	while (cur_offset < item_size) {
 		ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
 		len = btrfs_inode_ref_name_len(leaf, ref);
@@ -83,7 +81,7 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 	if (ret == -EEXIST) {
 		u32 old_size;
 
-		if (find_name_in_backref(path, name, name_len, &ref))
+		if (find_name_in_backref(path->nodes[0], path->slots[0], name, name_len, &ref))
 			goto out;
 
 		old_size = btrfs_item_size(path->nodes[0], path->slots[0]);
@@ -182,7 +180,7 @@ struct btrfs_inode_ref *btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
 	if (ret)
 		goto out;
 
-	find_name_in_backref(path, name, namelen, &ret_inode_ref);
+	find_name_in_backref(path->nodes[0], path->slots[0], name, namelen, &ret_inode_ref);
 out:
 	if (ret < 0)
 		return ERR_PTR(ret);
@@ -190,23 +188,20 @@ out:
 		return ret_inode_ref;
 }
 
-static int btrfs_find_name_in_ext_backref(struct btrfs_path *path,
-		u64 parent_ino, const char *name, int namelen,
-		struct btrfs_inode_extref **extref_ret)
+static int btrfs_find_name_in_ext_backref(struct extent_buffer *leaf,
+					  int slot, u64 parent_ino,
+					  const char *name, int namelen,
+					  struct btrfs_inode_extref **extref_ret)
 {
-	struct extent_buffer *node;
 	struct btrfs_inode_extref *extref;
 	unsigned long ptr;
 	unsigned long name_ptr;
 	u32 item_size;
 	u32 cur_offset = 0;
 	int ref_name_len;
-	int slot;
 
-	node = path->nodes[0];
-	slot = path->slots[0];
-	item_size = btrfs_item_size(node, slot);
-	ptr = btrfs_item_ptr_offset(node, slot);
+	item_size = btrfs_item_size(leaf, slot);
+	ptr = btrfs_item_ptr_offset(leaf, slot);
 
 	/*
 	 * Search all extended backrefs in this item. We're only looking
@@ -217,11 +212,11 @@ static int btrfs_find_name_in_ext_backref(struct btrfs_path *path,
 	while (cur_offset < item_size) {
 		extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
 		name_ptr = (unsigned long)(&extref->name);
-		ref_name_len = btrfs_inode_extref_name_len(node, extref);
+		ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
 
 		if (ref_name_len == namelen &&
-		    btrfs_inode_extref_parent(node, extref) == parent_ino &&
-		    (memcmp_extent_buffer(node, name, name_ptr, namelen) == 0))
+		    btrfs_inode_extref_parent(leaf, extref) == parent_ino &&
+		    (memcmp_extent_buffer(leaf, name, name_ptr, namelen) == 0))
 		{
 			if (extref_ret)
 				*extref_ret = extref;
@@ -253,7 +248,8 @@ struct btrfs_inode_extref *btrfs_lookup_inode_extref(struct btrfs_trans_handle
 		return ERR_PTR(ret);
 	if (ret > 0)
 		return NULL;
-	if (!btrfs_find_name_in_ext_backref(path, parent_ino, name,
+	if (!btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
+					    parent_ino, name,
 					    namelen, &extref))
 		return NULL;
 
@@ -294,7 +290,7 @@ int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
 	 * Sanity check - did we find the right item for this name?  This
 	 * should always succeed so error here will make the FS readonly.
 	 */
-	if (!btrfs_find_name_in_ext_backref(path, ref_objectid,
+	if (!btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0], ref_objectid,
 					    name, name_len, &extref)) {
 		ret = -ENOENT;
 		goto out;
@@ -356,14 +352,14 @@ int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
 	ret = btrfs_insert_empty_item(trans, root, path, &key,
 				      ins_len);
 	if (ret == -EEXIST) {
-		if (btrfs_find_name_in_ext_backref(path, ref_objectid,
+		if (btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
+						   ref_objectid,
 						   name, name_len, NULL))
 			goto out;
 
 		btrfs_extend_item(path, ins_len);
 		ret = 0;
 	}
-
 	if (ret < 0)
 		goto out;
 
@@ -382,7 +378,6 @@ int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
 
 out:
 	btrfs_free_path(path);
-
 	return ret;
 }
 
@@ -418,7 +413,7 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
 	} else if (ret < 0) {
 		goto out;
 	}
-	if (!find_name_in_backref(path, name, name_len, &ref)) {
+	if (!find_name_in_backref(path->nodes[0], path->slots[0], name, name_len, &ref)) {
 		ret = -ENOENT;
 		search_ext_refs = 1;
 		goto out;
diff --git a/kernel-shared/messages.c b/kernel-shared/messages.c
index 634f5961..1853ad71 100644
--- a/kernel-shared/messages.c
+++ b/kernel-shared/messages.c
@@ -269,12 +269,6 @@ void __cold btrfs_assertfail(const char *expr, const char *file, int line)
 }
 #endif
 
-void __cold btrfs_print_v0_err(struct btrfs_fs_info *fs_info)
-{
-	btrfs_err(fs_info,
-"Unsupported V0 extent filesystem detected. Aborting. Please re-create your filesystem with a newer kernel");
-}
-
 #if BITS_PER_LONG == 32 && defined(__KERNEL__)
 void __cold btrfs_warn_32bit_limit(struct btrfs_fs_info *fs_info)
 {
diff --git a/kernel-shared/root-tree.c b/kernel-shared/root-tree.c
index 33f9e469..dd2636ec 100644
--- a/kernel-shared/root-tree.c
+++ b/kernel-shared/root-tree.c
@@ -21,10 +21,12 @@
 #include <string.h>
 #include "kernel-lib/bitops.h"
 #include "kernel-shared/accessors.h"
+#include "kernel-shared/messages.h"
 #include "kernel-shared/extent_io.h"
 #include "kernel-shared/uapi/btrfs_tree.h"
 #include "kernel-shared/ctree.h"
 #include "kernel-shared/disk-io.h"
+#include "kernel-shared/transaction.h"
 
 int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
 			struct btrfs_root_item *item, struct btrfs_key *key)
@@ -74,6 +76,7 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
 		      *root, struct btrfs_key *key, struct btrfs_root_item
 		      *item)
 {
+	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct btrfs_path *path;
 	struct extent_buffer *l;
 	int ret;
@@ -88,7 +91,17 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
 	ret = btrfs_search_slot(trans, root, key, path, 0, 1);
 	if (ret < 0)
 		goto out;
-	BUG_ON(ret != 0);
+
+	if (ret > 0) {
+		btrfs_crit(fs_info,
+			"unable to find root key (%llu %u %llu) in tree %llu",
+			key->objectid, key->type, key->offset,
+			root->root_key.objectid);
+		ret = -EUCLEAN;
+		btrfs_abort_transaction(trans, ret);
+		goto out;
+	}
+
 	l = path->nodes[0];
 	slot = path->slots[0];
 	ptr = btrfs_item_ptr_offset(l, slot);
@@ -104,17 +117,20 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
 		ret = btrfs_search_slot(trans, root, key, path,
 				-1, 1);
 		if (ret < 0) {
+			btrfs_abort_transaction(trans, ret);
 			goto out;
 		}
 
 		ret = btrfs_del_item(trans, root, path);
 		if (ret < 0) {
+			btrfs_abort_transaction(trans, ret);
 			goto out;
 		}
 		btrfs_release_path(path);
 		ret = btrfs_insert_empty_item(trans, root, path,
 				key, sizeof(*item));
 		if (ret < 0) {
+			btrfs_abort_transaction(trans, ret);
 			goto out;
 		}
 		l = path->nodes[0];
diff --git a/kernel-shared/uuid-tree.c b/kernel-shared/uuid-tree.c
index e0d3ea09..7adbc11e 100644
--- a/kernel-shared/uuid-tree.c
+++ b/kernel-shared/uuid-tree.c
@@ -32,12 +32,13 @@
 #include "common/messages.h"
 #include "common/utils.h"
 
-void btrfs_uuid_to_key(const u8 *uuid, struct btrfs_key *key)
+void btrfs_uuid_to_key(const u8 *uuid, u8 type, struct btrfs_key *key)
 {
 	u64 tmp;
 
 	tmp = get_unaligned_le64(uuid);
 	put_unaligned_64(tmp, &key->objectid);
+	key->type = type;
 	tmp = get_unaligned_le64(uuid + sizeof(u64));
 	put_unaligned_64(tmp, &key->offset);
 }
@@ -57,8 +58,7 @@ static int btrfs_uuid_tree_lookup_any(int fd, const u8 *uuid, u8 type,
 	__le64 lesubid;
 	struct btrfs_key key;
 
-	key.type = type;
-	btrfs_uuid_to_key(uuid, &key);
+	btrfs_uuid_to_key(uuid, type, &key);
 
 	memset(&search_arg, 0, sizeof(search_arg));
 	search_arg.key.tree_id = BTRFS_UUID_TREE_OBJECTID;
@@ -138,8 +138,7 @@ int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, u8 *uuid, u8 type,
 		goto out;
 	}
 
-	btrfs_uuid_to_key(uuid, &key);
-	key.type = type;
+	btrfs_uuid_to_key(uuid, type, &key);
 
 	path = btrfs_alloc_path();
 	if (!path) {
diff --git a/mkfs/main.c b/mkfs/main.c
index d15f3c9a..c9c8ee5f 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -807,8 +807,7 @@ static int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, u8 *uuid,
 	unsigned long offset;
 	__le64 subvol_id_le;
 
-	key.type = type;
-	btrfs_uuid_to_key(uuid, &key);
+	btrfs_uuid_to_key(uuid, type, &key);
 
 	path = btrfs_alloc_path();
 	if (!path) {