[PATCH v4 09/18] btrfs: track owning root in btrfs_ref

[Boris Burkov <boris@bur.io>]

While data extents require us to store additional inline refs to track
the original owner on free, this information is available implicitly for
metadata. It is found in the owner field of the header of the tree
block. Even if other trees refer to this block and the original ref goes
away, we will not rewrite that header field, so it will reliably give the
original owner.

In addition, there is a relocation case where a new data extent needs to
have an owning root separate from the referring root wired through
delayed refs.

To use it for recording simple quota deltas, we need to wire this root
id through from when we create the delayed ref until we fully process
it. Store it in the generic btrfs_ref struct of the delayed ref.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 fs/btrfs/delayed-ref.c |  7 ++++---
 fs/btrfs/delayed-ref.h | 13 +++++++++++--
 fs/btrfs/extent-tree.c | 18 ++++++++++--------
 fs/btrfs/file.c        | 10 +++++-----
 fs/btrfs/inode-item.c  |  2 +-
 fs/btrfs/relocation.c  | 16 +++++++++-------
 fs/btrfs/tree-log.c    |  3 ++-
 7 files changed, 42 insertions(+), 27 deletions(-)

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index f0bae1e1c455..49c320f2334b 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -840,7 +840,7 @@ add_delayed_ref_head(struct btrfs_trans_handle *trans,
 static void init_delayed_ref_common(struct btrfs_fs_info *fs_info,
 				    struct btrfs_delayed_ref_node *ref,
 				    u64 bytenr, u64 num_bytes, u64 ref_root,
-				    int action, u8 ref_type)
+				    int action, u8 ref_type, u64 owning_root)
 {
 	u64 seq = 0;
 
@@ -857,6 +857,7 @@ static void init_delayed_ref_common(struct btrfs_fs_info *fs_info,
 	ref->action = action;
 	ref->seq = seq;
 	ref->type = ref_type;
+	ref->owning_root = owning_root;
 	RB_CLEAR_NODE(&ref->ref_node);
 	INIT_LIST_HEAD(&ref->add_list);
 }
@@ -915,7 +916,7 @@ int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
 
 	init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
 				generic_ref->tree_ref.ref_root, action,
-				ref_type);
+				ref_type, generic_ref->owning_root);
 	ref->root = generic_ref->tree_ref.ref_root;
 	ref->parent = parent;
 	ref->level = level;
@@ -989,7 +990,7 @@ int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
 	else
 	        ref_type = BTRFS_EXTENT_DATA_REF_KEY;
 	init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
-				ref_root, action, ref_type);
+				ref_root, action, ref_type, ref_root);
 	ref->root = ref_root;
 	ref->parent = parent;
 	ref->objectid = owner;
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index a71eff78469c..336c33c28191 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -32,6 +32,12 @@ struct btrfs_delayed_ref_node {
 	/* seq number to keep track of insertion order */
 	u64 seq;
 
+	/*
+	 * root which originally allocated this extent and owns it for
+	 * simple quota accounting purposes.
+	 */
+	u64 owning_root;
+
 	/* ref count on this data structure */
 	refcount_t refs;
 
@@ -239,6 +245,7 @@ struct btrfs_ref {
 #endif
 	u64 bytenr;
 	u64 len;
+	u64 owning_root;
 
 	/* Bytenr of the parent tree block */
 	u64 parent;
@@ -278,16 +285,18 @@ static inline u64 btrfs_calc_delayed_ref_bytes(const struct btrfs_fs_info *fs_in
 }
 
 static inline void btrfs_init_generic_ref(struct btrfs_ref *generic_ref,
-				int action, u64 bytenr, u64 len, u64 parent)
+				int action, u64 bytenr, u64 len, u64 parent, u64 owning_root)
 {
 	generic_ref->action = action;
 	generic_ref->bytenr = bytenr;
 	generic_ref->len = len;
 	generic_ref->parent = parent;
+	generic_ref->owning_root = owning_root;
 }
 
 static inline void btrfs_init_tree_ref(struct btrfs_ref *generic_ref,
-				int level, u64 root, u64 mod_root, bool skip_qgroup)
+				int level, u64 root, u64 mod_root,
+				bool skip_qgroup)
 {
 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 	/* If @real_root not set, use @root as fallback */
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 018e288ccf7d..8e9a0da55f4c 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2389,7 +2389,7 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
 			num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
 			key.offset -= btrfs_file_extent_offset(buf, fi);
 			btrfs_init_generic_ref(&generic_ref, action, bytenr,
-					       num_bytes, parent);
+					       num_bytes, parent, ref_root);
 			btrfs_init_data_ref(&generic_ref, ref_root, key.objectid,
 					    key.offset, root->root_key.objectid,
 					    for_reloc);
@@ -2403,7 +2403,7 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
 			bytenr = btrfs_node_blockptr(buf, i);
 			num_bytes = fs_info->nodesize;
 			btrfs_init_generic_ref(&generic_ref, action, bytenr,
-					       num_bytes, parent);
+					       num_bytes, parent, ref_root);
 			btrfs_init_tree_ref(&generic_ref, level - 1, ref_root,
 					    root->root_key.objectid, for_reloc);
 			if (inc)
@@ -3220,7 +3220,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
 	int ret;
 
 	btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
-			       buf->start, buf->len, parent);
+			       buf->start, buf->len, parent, btrfs_header_owner(buf));
 	btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf),
 			    root_id, 0, false);
 
@@ -4677,12 +4677,14 @@ int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
 				     struct btrfs_key *ins)
 {
 	struct btrfs_ref generic_ref = { 0 };
+	u64 root_objectid = root->root_key.objectid;
+	u64 owning_root = root_objectid;
 
-	BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
+	BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
 
 	btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
-			       ins->objectid, ins->offset, 0);
-	btrfs_init_data_ref(&generic_ref, root->root_key.objectid, owner,
+			       ins->objectid, ins->offset, 0, owning_root);
+	btrfs_init_data_ref(&generic_ref, root_objectid, owner,
 			    offset, 0, false);
 	btrfs_ref_tree_mod(root->fs_info, &generic_ref);
 
@@ -4894,7 +4896,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
 		extent_op->level = level;
 
 		btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
-				       ins.objectid, ins.offset, parent);
+				       ins.objectid, ins.offset, parent, btrfs_header_owner(buf));
 		btrfs_init_tree_ref(&generic_ref, level, root_objectid,
 				    root->root_key.objectid, false);
 		btrfs_ref_tree_mod(fs_info, &generic_ref);
@@ -5315,7 +5317,7 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans,
 		find_next_key(path, level, &wc->drop_progress);
 
 		btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
-				       fs_info->nodesize, parent);
+				       fs_info->nodesize, parent, btrfs_header_owner(next));
 		btrfs_init_tree_ref(&ref, level - 1, root->root_key.objectid,
 				    0, false);
 		ret = btrfs_free_extent(trans, &ref);
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index fd03e689a6be..83b651d823bb 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -373,7 +373,7 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 			if (update_refs && disk_bytenr > 0) {
 				btrfs_init_generic_ref(&ref,
 						BTRFS_ADD_DELAYED_REF,
-						disk_bytenr, num_bytes, 0);
+						disk_bytenr, num_bytes, 0, root->root_key.objectid);
 				btrfs_init_data_ref(&ref,
 						root->root_key.objectid,
 						new_key.objectid,
@@ -463,7 +463,7 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 			} else if (update_refs && disk_bytenr > 0) {
 				btrfs_init_generic_ref(&ref,
 						BTRFS_DROP_DELAYED_REF,
-						disk_bytenr, num_bytes, 0);
+						disk_bytenr, num_bytes, 0, root->root_key.objectid);
 				btrfs_init_data_ref(&ref,
 						root->root_key.objectid,
 						key.objectid,
@@ -745,7 +745,7 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 		btrfs_mark_buffer_dirty(leaf);
 
 		btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, bytenr,
-				       num_bytes, 0);
+				       num_bytes, 0, root->root_key.objectid);
 		btrfs_init_data_ref(&ref, root->root_key.objectid, ino,
 				    orig_offset, 0, false);
 		ret = btrfs_inc_extent_ref(trans, &ref);
@@ -771,7 +771,7 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 	other_start = end;
 	other_end = 0;
 	btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
-			       num_bytes, 0);
+			       num_bytes, 0, root->root_key.objectid);
 	btrfs_init_data_ref(&ref, root->root_key.objectid, ino, orig_offset,
 			    0, false);
 	if (extent_mergeable(leaf, path->slots[0] + 1,
@@ -2290,7 +2290,7 @@ static int btrfs_insert_replace_extent(struct btrfs_trans_handle *trans,
 
 		btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
 				       extent_info->disk_offset,
-				       extent_info->disk_len, 0);
+				       extent_info->disk_len, 0, root->root_key.objectid);
 		ref_offset = extent_info->file_offset - extent_info->data_offset;
 		btrfs_init_data_ref(&ref, root->root_key.objectid,
 				    btrfs_ino(inode), ref_offset, 0, false);
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index 4c322b720a80..4a56bf679de6 100644
--- a/fs/btrfs/inode-item.c
+++ b/fs/btrfs/inode-item.c
@@ -676,7 +676,7 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 			bytes_deleted += extent_num_bytes;
 
 			btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF,
-					extent_start, extent_num_bytes, 0);
+					extent_start, extent_num_bytes, 0, root->root_key.objectid);
 			btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
 					control->ino, extent_offset,
 					root->root_key.objectid, false);
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 9db2e6fa2cb2..8e0aee042179 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1158,7 +1158,7 @@ int replace_file_extents(struct btrfs_trans_handle *trans,
 
 		key.offset -= btrfs_file_extent_offset(leaf, fi);
 		btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
-				       num_bytes, parent);
+				       num_bytes, parent, root->root_key.objectid);
 		btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
 				    key.objectid, key.offset,
 				    root->root_key.objectid, false);
@@ -1169,7 +1169,7 @@ int replace_file_extents(struct btrfs_trans_handle *trans,
 		}
 
 		btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
-				       num_bytes, parent);
+				       num_bytes, parent, root->root_key.objectid);
 		btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
 				    key.objectid, key.offset,
 				    root->root_key.objectid, false);
@@ -1382,7 +1382,8 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
 		btrfs_mark_buffer_dirty(path->nodes[level]);
 
 		btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
-				       blocksize, path->nodes[level]->start);
+				       blocksize, path->nodes[level]->start,
+				       src->root_key.objectid);
 		btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid,
 				    0, true);
 		ret = btrfs_inc_extent_ref(trans, &ref);
@@ -1391,7 +1392,7 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
 			break;
 		}
 		btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
-				       blocksize, 0);
+				       blocksize, 0, dest->root_key.objectid);
 		btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid, 0,
 				    true);
 		ret = btrfs_inc_extent_ref(trans, &ref);
@@ -1401,7 +1402,8 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
 		}
 
 		btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
-				       blocksize, path->nodes[level]->start);
+				       blocksize, path->nodes[level]->start,
+				       src->root_key.objectid);
 		btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid,
 				    0, true);
 		ret = btrfs_free_extent(trans, &ref);
@@ -1411,7 +1413,7 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
 		}
 
 		btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
-				       blocksize, 0);
+				       blocksize, 0, src->root_key.objectid);
 		btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid,
 				    0, true);
 		ret = btrfs_free_extent(trans, &ref);
@@ -2491,7 +2493,7 @@ static int do_relocation(struct btrfs_trans_handle *trans,
 
 			btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
 					       node->eb->start, blocksize,
-					       upper->eb->start);
+					       upper->eb->start, btrfs_header_owner(upper->eb));
 			btrfs_init_tree_ref(&ref, node->level,
 					    btrfs_header_owner(upper->eb),
 					    root->root_key.objectid, false);
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 8ad7e7e38d18..51aaaefaf39d 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -767,7 +767,8 @@ static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 			} else if (ret == 0) {
 				btrfs_init_generic_ref(&ref,
 						BTRFS_ADD_DELAYED_REF,
-						ins.objectid, ins.offset, 0);
+						ins.objectid, ins.offset, 0,
+						root->root_key.objectid);
 				btrfs_init_data_ref(&ref,
 						root->root_key.objectid,
 						key->objectid, offset, 0, false);
-- 
2.41.0