Remove offset field from struct btrfs_extent_ref

The offset field in struct btrfs_extent_ref records the position
inside file that file extent is referenced by. In the new back
reference system, tree leaves holding reference to file extent
are recorded explicitly. We can quickly scan these tree leaves, so the
offset field is not required.

This patch also makes the back reference system check the objectid
when extents are being deleted

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

1 files changed, 45 insertions, 65 deletions

diff --git a/extent-tree.c b/extent-tree.c
index a3298030..e5c304ca 100644
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -474,13 +474,15 @@ found:
 
 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
 					  struct btrfs_root *root,
-					  struct btrfs_path *path, u64 bytenr,
-					  u64 parent, u64 ref_root,
-					  u64 ref_generation, int del)
+					  struct btrfs_path *path,
+					  u64 bytenr, u64 parent,
+					  u64 ref_root, u64 ref_generation,
+					  u64 owner_objectid, int del)
 {
 	struct btrfs_key key;
 	struct btrfs_extent_ref *ref;
 	struct extent_buffer *leaf;
+	u64 ref_objectid;
 	int ret;
 
 	key.objectid = bytenr;
@@ -497,8 +499,11 @@ static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
 
 	leaf = path->nodes[0];
 	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
+	ref_objectid = btrfs_ref_objectid(leaf, ref);
 	if (btrfs_ref_root(leaf, ref) != ref_root ||
-	    btrfs_ref_generation(leaf, ref) != ref_generation) {
+	    btrfs_ref_generation(leaf, ref) != ref_generation ||
+	    (ref_objectid != owner_objectid &&
+	     ref_objectid != BTRFS_MULTIPLE_OBJECTIDS)) {
 		ret = -EIO;
 		WARN_ON(1);
 		goto out;
@@ -513,7 +518,7 @@ static int noinline insert_extent_backref(struct btrfs_trans_handle *trans,
 					  struct btrfs_path *path,
 					  u64 bytenr, u64 parent,
 					  u64 ref_root, u64 ref_generation,
-					  u64 owner_objectid, u64 owner_offset)
+					  u64 owner_objectid)
 {
 	struct btrfs_key key;
 	struct extent_buffer *leaf;
@@ -533,7 +538,6 @@ static int noinline insert_extent_backref(struct btrfs_trans_handle *trans,
 		btrfs_set_ref_root(leaf, ref, ref_root);
 		btrfs_set_ref_generation(leaf, ref, ref_generation);
 		btrfs_set_ref_objectid(leaf, ref, owner_objectid);
-		btrfs_set_ref_offset(leaf, ref, owner_offset);
 		btrfs_set_ref_num_refs(leaf, ref, 1);
 	} else if (ret == -EEXIST) {
 		u64 existing_owner;
@@ -553,14 +557,10 @@ static int noinline insert_extent_backref(struct btrfs_trans_handle *trans,
 		btrfs_set_ref_num_refs(leaf, ref, num_refs + 1);
 
 		existing_owner = btrfs_ref_objectid(leaf, ref);
-		if (existing_owner == owner_objectid &&
-		    btrfs_ref_offset(leaf, ref) > owner_offset) {
-			btrfs_set_ref_offset(leaf, ref, owner_offset);
-		} else if (existing_owner != owner_objectid &&
-			   existing_owner != BTRFS_MULTIPLE_OBJECTIDS) {
+		if (existing_owner != owner_objectid &&
+		    existing_owner != BTRFS_MULTIPLE_OBJECTIDS) {
 			btrfs_set_ref_objectid(leaf, ref,
 					BTRFS_MULTIPLE_OBJECTIDS);
-			btrfs_set_ref_offset(leaf, ref, 0);
 		}
 		ret = 0;
 	} else {
@@ -601,7 +601,7 @@ static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 				     u64 orig_parent, u64 parent,
 				     u64 orig_root, u64 ref_root,
 				     u64 orig_generation, u64 ref_generation,
-				     u64 owner_objectid, u64 owner_offset)
+				     u64 owner_objectid)
 {
 	int ret;
 	struct btrfs_root *extent_root = root->fs_info->extent_root;
@@ -652,7 +652,7 @@ static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 		return -ENOMEM;
 	ret = lookup_extent_backref(trans, extent_root, path,
 				    bytenr, orig_parent, orig_root,
-				    orig_generation, 1);
+				    orig_generation, owner_objectid, 1);
 	if (ret)
 		goto out;
 	ret = remove_extent_backref(trans, extent_root, path);
@@ -660,7 +660,7 @@ static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 		goto out;
 	ret = insert_extent_backref(trans, extent_root, path, bytenr,
 				    parent, ref_root, ref_generation,
-				    owner_objectid, owner_offset);
+				    owner_objectid);
 	BUG_ON(ret);
 	finish_current_insert(trans, extent_root);
 	del_pending_extents(trans, extent_root);
@@ -673,7 +673,7 @@ int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 			    struct btrfs_root *root, u64 bytenr,
 			    u64 orig_parent, u64 parent,
 			    u64 ref_root, u64 ref_generation,
-			    u64 owner_objectid, u64 owner_offset)
+			    u64 owner_objectid)
 {
 	int ret;
 	if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
@@ -683,7 +683,7 @@ int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
 	ret = __btrfs_update_extent_ref(trans, root, bytenr, orig_parent,
 					parent, ref_root, ref_root,
 					ref_generation, ref_generation,
-					owner_objectid, owner_offset);
+					owner_objectid);
 	maybe_unlock_mutex(root);
 	return ret;
 }
@@ -693,7 +693,7 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 				  u64 orig_parent, u64 parent,
 				  u64 orig_root, u64 ref_root,
 				  u64 orig_generation, u64 ref_generation,
-				  u64 owner_objectid, u64 owner_offset)
+				  u64 owner_objectid)
 {
 	struct btrfs_path *path;
 	int ret;
@@ -735,7 +735,7 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 	ret = insert_extent_backref(trans, root->fs_info->extent_root,
 				    path, bytenr, parent,
 				    ref_root, ref_generation,
-				    owner_objectid, owner_offset);
+				    owner_objectid);
 	BUG_ON(ret);
 	finish_current_insert(trans, root->fs_info->extent_root);
 	del_pending_extents(trans, root->fs_info->extent_root);
@@ -748,7 +748,7 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 			 struct btrfs_root *root,
 			 u64 bytenr, u64 num_bytes, u64 parent,
 			 u64 ref_root, u64 ref_generation,
-			 u64 owner_objectid, u64 owner_offset)
+			 u64 owner_objectid)
 {
 	int ret;
 	if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
@@ -757,7 +757,7 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 	maybe_lock_mutex(root);
 	ret = __btrfs_inc_extent_ref(trans, root, bytenr, 0, parent,
 				     0, ref_root, 0, ref_generation,
-				     owner_objectid, owner_offset);
+				     owner_objectid);
 	maybe_unlock_mutex(root);
 	return ret;
 }
@@ -821,7 +821,7 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 	int ret = 0;
 	int faili = 0;
 	int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
-			    u64, u64, u64, u64, u64, u64, u64, u64, u64);
+			    u64, u64, u64, u64, u64, u64, u64, u64);
 
 	ref_root = btrfs_header_owner(buf);
 	ref_generation = btrfs_header_generation(buf);
@@ -862,7 +862,7 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 					   orig_buf->start, buf->start,
 					   orig_root, ref_root,
 					   orig_generation, ref_generation,
-					   key.objectid, key.offset);
+					   key.objectid);
 			maybe_unlock_mutex(root);
 
 			if (ret) {
@@ -877,7 +877,7 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 					   orig_buf->start, buf->start,
 					   orig_root, ref_root,
 					   orig_generation, ref_generation,
-					   level - 1, 0);
+					   level - 1);
 			maybe_unlock_mutex(root);
 			if (ret) {
 				faili = i;
@@ -978,7 +978,7 @@ int btrfs_update_ref(struct btrfs_trans_handle *trans,
 					    orig_buf->start, buf->start,
 					    orig_root, ref_root,
 					    orig_generation, ref_generation,
-					    key.objectid, key.offset);
+					    key.objectid);
 			maybe_unlock_mutex(root);
 			if (ret)
 				goto fail;
@@ -989,7 +989,7 @@ int btrfs_update_ref(struct btrfs_trans_handle *trans,
 					    orig_buf->start, buf->start,
 					    orig_root, ref_root,
 					    orig_generation, ref_generation,
-					    level - 1, 0);
+					    level - 1);
 			maybe_unlock_mutex(root);
 			if (ret)
 				goto fail;
@@ -1344,13 +1344,14 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
 						start, extent_op->parent,
 						extent_root->root_key.objectid,
 						extent_op->generation,
-						extent_op->level, 0);
+						extent_op->level);
 			BUG_ON(err);
 		} else if (extent_op->type == PENDING_BACKREF_UPDATE) {
 			err = lookup_extent_backref(trans, extent_root, path,
 						start, extent_op->orig_parent,
 						extent_root->root_key.objectid,
-						extent_op->orig_generation, 0);
+						extent_op->orig_generation,
+						extent_op->level, 0);
 			BUG_ON(err);
 
 			clear_extent_bits(&info->extent_ins, start, end,
@@ -1422,8 +1423,7 @@ pinit:
 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 			 *root, u64 bytenr, u64 num_bytes, u64 parent,
 			 u64 root_objectid, u64 ref_generation,
-			 u64 owner_objectid, u64 owner_offset, int pin,
-			 int mark_free)
+			 u64 owner_objectid, int pin, int mark_free)
 {
 	struct btrfs_path *path;
 	struct btrfs_key key;
@@ -1446,8 +1446,9 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 	if (!path)
 		return -ENOMEM;
 
-	ret = lookup_extent_backref(trans, extent_root, path, bytenr, parent,
-				    root_objectid, ref_generation, 1);
+	ret = lookup_extent_backref(trans, extent_root, path,
+				    bytenr, parent, root_objectid,
+				    ref_generation, owner_objectid, 1);
 	if (ret == 0) {
 		struct btrfs_key found_key;
 		extent_slot = path->slots[0];
@@ -1477,12 +1478,11 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 	} else {
 		btrfs_print_leaf(extent_root, path->nodes[0]);
 		printk("Unable to find ref byte nr %llu root %llu "
-		       " gen %llu owner %llu offset %llu\n",
+		       " gen %llu owner %llu\n",
 		       (unsigned long long)bytenr,
 		       (unsigned long long)root_objectid,
 		       (unsigned long long)ref_generation,
-		       (unsigned long long)owner_objectid,
-		       (unsigned long long)owner_offset);
+		       (unsigned long long)owner_objectid);
 		BUG_ON(1);
 	}
 
@@ -1602,7 +1602,7 @@ free_extent:
 					    extent_op->orig_parent,
 					    extent_root->root_key.objectid,
 					    extent_op->orig_generation,
-					    extent_op->level, 0, 0, mark_free);
+					    extent_op->level, 0, mark_free);
 			kfree(extent_op);
 		} else {
 			kfree(extent_op);
@@ -1634,7 +1634,7 @@ free_extent:
 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 		      *root, u64 bytenr, u64 num_bytes, u64 parent,
 		      u64 root_objectid, u64 ref_generation,
-		      u64 owner_objectid, u64 owner_offset, int pin)
+		      u64 owner_objectid, int pin)
 {
 	struct btrfs_root *extent_root = root->fs_info->extent_root;
 	int pending_ret;
@@ -1665,7 +1665,7 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 	}
 	ret = __free_extent(trans, root, bytenr, num_bytes, parent,
 			    root_objectid, ref_generation,
-			    owner_objectid, owner_offset, pin, pin == 0);
+			    owner_objectid, pin, pin == 0);
 	pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
 	return ret ? ret : pending_ret;
 }
@@ -1809,8 +1809,7 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 		       struct btrfs_root *root,
 		       u64 num_bytes, u64 parent,
 		       u64 root_objectid, u64 ref_generation,
-		       u64 owner, u64 owner_offset,
-		       u64 empty_size, u64 hint_byte,
+		       u64 owner, u64 empty_size, u64 hint_byte,
 		       u64 search_end, struct btrfs_key *ins, int data)
 {
 	int ret;
@@ -1935,7 +1934,6 @@ found:
 	btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
 	btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
 	btrfs_set_ref_objectid(path->nodes[0], ref, owner);
-	btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
 	btrfs_set_ref_num_refs(path->nodes[0], ref, 1);
 
 	btrfs_mark_buffer_dirty(path->nodes[0]);
@@ -1983,7 +1981,7 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 
 	ret = btrfs_alloc_extent(trans, root, blocksize, parent,
 				 root_objectid, ref_generation,
-				 level, 0, empty_size, hint,
+				 level, empty_size, hint,
 				 (u64)-1, &ins, 0);
 	if (ret) {
 		BUG_ON(ret > 0);
@@ -1995,7 +1993,7 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 			parent = ins.objectid;
 		btrfs_free_extent(trans, root, ins.objectid, blocksize,
 				  parent, root->root_key.objectid,
-				  ref_generation, 0, 0, 0);
+				  ref_generation, level, 0);
 		BUG_ON(1);
 		return ERR_PTR(-ENOMEM);
 	}
@@ -2041,7 +2039,7 @@ static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
 		ret = btrfs_free_extent(trans, root, disk_bytenr,
 				btrfs_file_extent_disk_num_bytes(leaf, fi),
 				leaf->start, leaf_owner, leaf_generation,
-				key.objectid, key.offset, 0);
+				key.objectid, 0);
 		BUG_ON(ret);
 	}
 	return 0;
@@ -2153,7 +2151,7 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
 			path->slots[*level]++;
 			ret = btrfs_free_extent(trans, root, bytenr, blocksize,
 						parent->start, root_owner,
-						root_gen, 0, 0, 1);
+						root_gen, *level - 1, 1);
 			BUG_ON(ret);
 			continue;
 		}
@@ -2165,24 +2163,6 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
 			next = read_tree_block(root, bytenr, blocksize,
 					       ptr_gen);
 			mutex_lock(&root->fs_info->fs_mutex);
-
-			/* we dropped the lock, check one more time */
-			ret = lookup_extent_ref(trans, root, bytenr,
-						blocksize, &refs);
-			BUG_ON(ret);
-			if (refs != 1) {
-				parent = path->nodes[*level];
-				root_owner = btrfs_header_owner(parent);
-				root_gen = btrfs_header_generation(parent);
-
-				path->slots[*level]++;
-				free_extent_buffer(next);
-				ret = btrfs_free_extent(trans, root, bytenr,
-						blocksize, parent->start,
-						root_owner, root_gen, 0, 0, 1);
-				BUG_ON(ret);
-				continue;
-			}
 		}
 		WARN_ON(*level <= 0);
 		if (path->nodes[*level-1])
@@ -2206,7 +2186,7 @@ out:
 	root_gen = btrfs_header_generation(parent);
 	ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
 				path->nodes[*level]->len, parent->start,
-				root_owner, root_gen, 0, 0, 1);
+				root_owner, root_gen, *level, 1);
 	free_extent_buffer(path->nodes[*level]);
 	path->nodes[*level] = NULL;
 	*level += 1;
@@ -2257,7 +2237,7 @@ static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
 						path->nodes[*level]->start,
 						path->nodes[*level]->len,
 						parent->start, root_owner,
-						root_gen, 0, 0, 1);
+						root_gen, *level, 1);
 			BUG_ON(ret);
 			free_extent_buffer(path->nodes[*level]);
 			path->nodes[*level] = NULL;