1 files changed, 157 insertions, 83 deletions

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 366978c..fd13101 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -24,6 +24,79 @@
 #include "delayed-ref.h"
 #include "locking.h"
 
+struct extent_inode_elem {
+	u64 inum;
+	u64 offset;
+	struct extent_inode_elem *next;
+};
+
+static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
+				struct btrfs_file_extent_item *fi,
+				u64 extent_item_pos,
+				struct extent_inode_elem **eie)
+{
+	u64 data_offset;
+	u64 data_len;
+	struct extent_inode_elem *e;
+
+	data_offset = btrfs_file_extent_offset(eb, fi);
+	data_len = btrfs_file_extent_num_bytes(eb, fi);
+
+	if (extent_item_pos < data_offset ||
+	    extent_item_pos >= data_offset + data_len)
+		return 1;
+
+	e = kmalloc(sizeof(*e), GFP_NOFS);
+	if (!e)
+		return -ENOMEM;
+
+	e->next = *eie;
+	e->inum = key->objectid;
+	e->offset = key->offset + (extent_item_pos - data_offset);
+	*eie = e;
+
+	return 0;
+}
+
+static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte,
+				u64 extent_item_pos,
+				struct extent_inode_elem **eie)
+{
+	u64 disk_byte;
+	struct btrfs_key key;
+	struct btrfs_file_extent_item *fi;
+	int slot;
+	int nritems;
+	int extent_type;
+	int ret;
+
+	/*
+	 * from the shared data ref, we only have the leaf but we need
+	 * the key. thus, we must look into all items and see that we
+	 * find one (some) with a reference to our extent item.
+	 */
+	nritems = btrfs_header_nritems(eb);
+	for (slot = 0; slot < nritems; ++slot) {
+		btrfs_item_key_to_cpu(eb, &key, slot);
+		if (key.type != BTRFS_EXTENT_DATA_KEY)
+			continue;
+		fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
+		extent_type = btrfs_file_extent_type(eb, fi);
+		if (extent_type == BTRFS_FILE_EXTENT_INLINE)
+			continue;
+		/* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
+		disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
+		if (disk_byte != wanted_disk_byte)
+			continue;
+
+		ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
 /*
  * this structure records all encountered refs on the way up to the root
  */
@@ -103,15 +176,16 @@ 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,
-				struct extent_buffer *eb, int level,
-				u64 wanted_objectid, u64 wanted_disk_byte)
+				struct ulist *parents, int level,
+				struct btrfs_key *key, u64 wanted_disk_byte,
+				const u64 *extent_item_pos)
 {
 	int ret;
 	int slot;
+	struct extent_buffer *eb = path->nodes[level];
 	struct btrfs_file_extent_item *fi;
-	struct btrfs_key key;
 	u64 disk_byte;
+	u64 wanted_objectid = key->objectid;
 
 add_parent:
 	ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
@@ -136,9 +210,9 @@ add_parent:
 
 		eb = path->nodes[0];
 		for (slot = 0; slot < btrfs_header_nritems(eb); ++slot) {
-			btrfs_item_key_to_cpu(eb, &key, slot);
-			if (key.objectid != wanted_objectid ||
-			    key.type != BTRFS_EXTENT_DATA_KEY)
+			btrfs_item_key_to_cpu(eb, key, slot);
+			if (key->objectid != wanted_objectid ||
+			    key->type != BTRFS_EXTENT_DATA_KEY)
 				return 0;
 			fi = btrfs_item_ptr(eb, slot,
 						struct btrfs_file_extent_item);
@@ -158,7 +232,8 @@ add_parent:
 static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
 					int search_commit_root,
 					struct __prelim_ref *ref,
-					struct ulist *parents)
+					struct ulist *parents,
+					const u64 *extent_item_pos)
 {
 	struct btrfs_path *path;
 	struct btrfs_root *root;
@@ -219,9 +294,8 @@ static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
 		btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
 	}
 
-	/* the last two parameters will only be used for level == 0 */
-	ret = add_all_parents(root, path, parents, eb, level, key.objectid,
-				ref->wanted_disk_byte);
+	ret = add_all_parents(root, path, parents, level, &key,
+				ref->wanted_disk_byte, extent_item_pos);
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -232,7 +306,8 @@ out:
  */
 static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
 				   int search_commit_root,
-				   struct list_head *head)
+				   struct list_head *head,
+				   const u64 *extent_item_pos)
 {
 	int err;
 	int ret = 0;
@@ -258,7 +333,7 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
 		if (ref->count == 0)
 			continue;
 		err = __resolve_indirect_ref(fs_info, search_commit_root,
-					     ref, parents);
+					     ref, parents, extent_item_pos);
 		if (err) {
 			if (ret == 0)
 				ret = err;
@@ -675,7 +750,8 @@ static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
  */
 static int find_parent_nodes(struct btrfs_trans_handle *trans,
 			     struct btrfs_fs_info *fs_info, u64 bytenr,
-			     u64 seq, struct ulist *refs, struct ulist *roots)
+			     u64 seq, struct ulist *refs, struct ulist *roots,
+			     const u64 *extent_item_pos)
 {
 	struct btrfs_key key;
 	struct btrfs_path *path;
@@ -778,7 +854,8 @@ again:
 	if (ret)
 		goto out;
 
-	ret = __resolve_indirect_refs(fs_info, search_commit_root, &prefs);
+	ret = __resolve_indirect_refs(fs_info, search_commit_root, &prefs,
+				      extent_item_pos);
 	if (ret)
 		goto out;
 
@@ -797,7 +874,21 @@ again:
 			BUG_ON(ret < 0);
 		}
 		if (ref->count && ref->parent) {
-			ret = ulist_add(refs, ref->parent, 0, GFP_NOFS);
+			struct extent_inode_elem *eie = NULL;
+			if (extent_item_pos) {
+				u32 bsz;
+				struct extent_buffer *eb;
+				bsz = btrfs_level_size(fs_info->extent_root,
+							info_level);
+				eb = read_tree_block(fs_info->extent_root,
+							   ref->parent, bsz, 0);
+				BUG_ON(!eb);
+				ret = find_extent_in_eb(eb, bytenr,
+							*extent_item_pos, &eie);
+				free_extent_buffer(eb);
+			}
+			ret = ulist_add(refs, ref->parent,
+					(unsigned long)eie, GFP_NOFS);
 			BUG_ON(ret < 0);
 		}
 		kfree(ref);
@@ -822,6 +913,28 @@ out:
 	return ret;
 }
 
+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);
+	while ((node = ulist_next(blocks, &uiter))) {
+		if (!node->aux)
+			continue;
+		eie = (struct extent_inode_elem *)node->aux;
+		for (; eie; eie = eie_next) {
+			eie_next = eie->next;
+			kfree(eie);
+		}
+		node->aux = 0;
+	}
+
+	ulist_free(blocks);
+}
+
 /*
  * Finds all leafs with a reference to the specified combination of bytenr and
  * offset. key_list_head will point to a list of corresponding keys (caller must
@@ -832,7 +945,8 @@ out:
  */
 static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
 				struct btrfs_fs_info *fs_info, u64 bytenr,
-				u64 num_bytes, u64 seq, struct ulist **leafs)
+				u64 seq, struct ulist **leafs,
+				const u64 *extent_item_pos)
 {
 	struct ulist *tmp;
 	int ret;
@@ -846,11 +960,12 @@ static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
 		return -ENOMEM;
 	}
 
-	ret = find_parent_nodes(trans, fs_info, bytenr, seq, *leafs, tmp);
+	ret = find_parent_nodes(trans, fs_info, bytenr, seq, *leafs, tmp,
+				extent_item_pos);
 	ulist_free(tmp);
 
 	if (ret < 0 && ret != -ENOENT) {
-		ulist_free(*leafs);
+		free_leaf_list(*leafs);
 		return ret;
 	}
 
@@ -872,7 +987,7 @@ static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
  */
 int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
 				struct btrfs_fs_info *fs_info, u64 bytenr,
-				u64 num_bytes, u64 seq, struct ulist **roots)
+				u64 seq, struct ulist **roots)
 {
 	struct ulist *tmp;
 	struct ulist_node *node = NULL;
@@ -891,7 +1006,7 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
 	ULIST_ITER_INIT(&uiter);
 	while (1) {
 		ret = find_parent_nodes(trans, fs_info, bytenr, seq,
-					tmp, *roots);
+					tmp, *roots, NULL);
 		if (ret < 0 && ret != -ENOENT) {
 			ulist_free(tmp);
 			ulist_free(*roots);
@@ -1183,67 +1298,25 @@ int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
 	return 0;
 }
 
-static int iterate_leaf_refs(struct btrfs_fs_info *fs_info, u64 logical,
-				u64 orig_extent_item_objectid,
-				u64 extent_item_pos, u64 root,
+static int iterate_leaf_refs(struct extent_inode_elem *inode_list,
+				u64 root, u64 extent_item_objectid,
 				iterate_extent_inodes_t *iterate, void *ctx)
 {
-	u64 disk_byte;
-	struct btrfs_key key;
-	struct btrfs_file_extent_item *fi;
-	struct extent_buffer *eb;
-	int slot;
-	int nritems;
+	struct extent_inode_elem *eie;
 	int ret = 0;
-	int extent_type;
-	u64 data_offset;
-	u64 data_len;
-
-	eb = read_tree_block(fs_info->tree_root, logical,
-				fs_info->tree_root->leafsize, 0);
-	if (!eb)
-		return -EIO;
-
-	/*
-	 * from the shared data ref, we only have the leaf but we need
-	 * the key. thus, we must look into all items and see that we
-	 * find one (some) with a reference to our extent item.
-	 */
-	nritems = btrfs_header_nritems(eb);
-	for (slot = 0; slot < nritems; ++slot) {
-		btrfs_item_key_to_cpu(eb, &key, slot);
-		if (key.type != BTRFS_EXTENT_DATA_KEY)
-			continue;
-		fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
-		extent_type = btrfs_file_extent_type(eb, fi);
-		if (extent_type == BTRFS_FILE_EXTENT_INLINE)
-			continue;
-		/* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
-		disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
-		if (disk_byte != orig_extent_item_objectid)
-			continue;
-
-		data_offset = btrfs_file_extent_offset(eb, fi);
-		data_len = btrfs_file_extent_num_bytes(eb, fi);
-
-		if (extent_item_pos < data_offset ||
-		    extent_item_pos >= data_offset + data_len)
-			continue;
 
+	for (eie = inode_list; eie; eie = eie->next) {
 		pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
-				"root %llu\n", orig_extent_item_objectid,
-				key.objectid, key.offset, root);
-		ret = iterate(key.objectid,
-				key.offset + (extent_item_pos - data_offset),
-				root, ctx);
+			 "root %llu\n", extent_item_objectid,
+			 eie->inum, eie->offset, root);
+		ret = iterate(eie->inum, eie->offset, root, ctx);
 		if (ret) {
-			pr_debug("stopping iteration because ret=%d\n", ret);
+			pr_debug("stopping iteration for %llu due to ret=%d\n",
+				 extent_item_objectid, ret);
 			break;
 		}
 	}
 
-	free_extent_buffer(eb);
-
 	return ret;
 }
 
@@ -1287,30 +1360,31 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
 	}
 
 	ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
-				   extent_item_pos, seq_elem.seq,
-				   &refs);
-
+				   seq_elem.seq, &refs, &extent_item_pos);
 	if (ret)
 		goto out;
 
 	ULIST_ITER_INIT(&ref_uiter);
 	while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
-		ret = btrfs_find_all_roots(trans, fs_info, ref_node->val, -1,
+		ret = btrfs_find_all_roots(trans, fs_info, ref_node->val,
 						seq_elem.seq, &roots);
 		if (ret)
 			break;
 		ULIST_ITER_INIT(&root_uiter);
 		while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
-			pr_debug("root %llu references leaf %llu\n",
-					root_node->val, ref_node->val);
-			ret = iterate_leaf_refs(fs_info, ref_node->val,
-						extent_item_objectid,
-						extent_item_pos, root_node->val,
-						iterate, ctx);
+			pr_debug("root %llu references leaf %llu, data list "
+				 "%#lx\n", root_node->val, ref_node->val,
+				 ref_node->aux);
+			ret = iterate_leaf_refs(
+				(struct extent_inode_elem *)ref_node->aux,
+				root_node->val, extent_item_objectid,
+				iterate, ctx);
 		}
+		ulist_free(roots);
+		roots = NULL;
 	}
 
-	ulist_free(refs);
+	free_leaf_list(refs);
 	ulist_free(roots);
 out:
 	if (!search_commit_root) {