Merge branch 'for-chris' of git://git.jan-o-sch.net/btrfs-unstable into for-linus

Conflicts:
	fs/btrfs/ulist.h

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 350 insertions, 145 deletions

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index bcec06750232..3f75895c919b 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -24,22 +24,135 @@
 #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
  */
 struct __prelim_ref {
         struct list_head list;
         u64 root_id;
-        struct btrfs_key key;
+        struct btrfs_key key_for_search;
         int level;
         int count;
+        struct extent_inode_elem *inode_list;
         u64 parent;
         u64 wanted_disk_byte;
 };
 
+/*
+ * the rules for all callers of this function are:
+ * - obtaining the parent is the goal
+ * - if you add a key, you must know that it is a correct key
+ * - if you cannot add the parent or a correct key, then we will look into the
+ *   block later to set a correct key
+ *
+ * delayed refs
+ * ============
+ *        backref type | shared | indirect | shared | indirect
+ * information         |   tree |     tree |   data |     data
+ * --------------------+--------+----------+--------+----------
+ *      parent logical |    y   |     -    |    -   |     -
+ *      key to resolve |    -   |     y    |    y   |     y
+ *  tree block logical |    -   |     -    |    -   |     -
+ *  root for resolving |    y   |     y    |    y   |     y
+ *
+ * - column 1:       we've the parent -> done
+ * - column 2, 3, 4: we use the key to find the parent
+ *
+ * on disk refs (inline or keyed)
+ * ==============================
+ *        backref type | shared | indirect | shared | indirect
+ * information         |   tree |     tree |   data |     data
+ * --------------------+--------+----------+--------+----------
+ *      parent logical |    y   |     -    |    y   |     -
+ *      key to resolve |    -   |     -    |    -   |     y
+ *  tree block logical |    y   |     y    |    y   |     y
+ *  root for resolving |    -   |     y    |    y   |     y
+ *
+ * - column 1, 3: we've the parent -> done
+ * - column 2:    we take the first key from the block to find the parent
+ *                (see __add_missing_keys)
+ * - column 4:    we use the key to find the parent
+ *
+ * additional information that's available but not required to find the parent
+ * block might help in merging entries to gain some speed.
+ */
+
 static int __add_prelim_ref(struct list_head *head, u64 root_id,
-                            struct btrfs_key *key, int level, u64 parent,
-                            u64 wanted_disk_byte, int count)
+                            struct btrfs_key *key, int level,
+                            u64 parent, u64 wanted_disk_byte, int count)
 {
         struct __prelim_ref *ref;
 
@@ -50,10 +163,11 @@ static int __add_prelim_ref(struct list_head *head, u64 root_id,
 
         ref->root_id = root_id;
         if (key)
-                ref->key = *key;
+                ref->key_for_search = *key;
         else
-                memset(&ref->key, 0, sizeof(ref->key));
+                memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
 
+        ref->inode_list = NULL;
         ref->level = level;
         ref->count = count;
         ref->parent = parent;
@@ -64,18 +178,26 @@ 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;
+        int slot = path->slots[level];
+        struct extent_buffer *eb = path->nodes[level];
         struct btrfs_file_extent_item *fi;
-        struct btrfs_key key;
+        struct extent_inode_elem *eie = NULL;
         u64 disk_byte;
+        u64 wanted_objectid = key->objectid;
 
 add_parent:
-        ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
+        if (level == 0 && extent_item_pos) {
+                fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
+                ret = check_extent_in_eb(key, eb, fi, *extent_item_pos, &eie);
+                if (ret < 0)
+                        return ret;
+        }
+        ret = ulist_add(parents, eb->start, (unsigned long)eie, GFP_NOFS);
         if (ret < 0)
                 return ret;
 
@@ -89,6 +211,7 @@ add_parent:
          * repeat this until we don't find any additional EXTENT_DATA items.
          */
         while (1) {
+                eie = NULL;
                 ret = btrfs_next_leaf(root, path);
                 if (ret < 0)
                         return ret;
@@ -97,9 +220,9 @@ 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);
@@ -118,8 +241,10 @@ add_parent:
  */
 static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
                                         int search_commit_root,
+                                        u64 time_seq,
                                         struct __prelim_ref *ref,
-                                        struct ulist *parents)
+                                        struct ulist *parents,
+                                        const u64 *extent_item_pos)
 {
         struct btrfs_path *path;
         struct btrfs_root *root;
@@ -152,12 +277,13 @@ static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
                 goto out;
 
         path->lowest_level = level;
-        ret = btrfs_search_slot(NULL, root, &ref->key, path, 0, 0);
+        ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq);
         pr_debug("search slot in root %llu (level %d, ref count %d) returned "
                  "%d for key (%llu %u %llu)\n",
                  (unsigned long long)ref->root_id, level, ref->count, ret,
-                 (unsigned long long)ref->key.objectid, ref->key.type,
-                 (unsigned long long)ref->key.offset);
+                 (unsigned long long)ref->key_for_search.objectid,
+                 ref->key_for_search.type,
+                 (unsigned long long)ref->key_for_search.offset);
         if (ret < 0)
                 goto out;
 
@@ -179,9 +305,8 @@ 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;
@@ -191,8 +316,9 @@ out:
  * resolve all indirect backrefs from the list
  */
 static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
-                                   int search_commit_root,
-                                   struct list_head *head)
+                                   int search_commit_root, u64 time_seq,
+                                   struct list_head *head,
+                                   const u64 *extent_item_pos)
 {
         int err;
         int ret = 0;
@@ -201,6 +327,7 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
         struct __prelim_ref *new_ref;
         struct ulist *parents;
         struct ulist_node *node;
+        struct ulist_iterator uiter;
 
         parents = ulist_alloc(GFP_NOFS);
         if (!parents)
@@ -217,7 +344,8 @@ 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);
+                                             time_seq, ref, parents,
+                                             extent_item_pos);
                 if (err) {
                         if (ret == 0)
                                 ret = err;
@@ -225,11 +353,14 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
                 }
 
                 /* we put the first parent into the ref at hand */
-                node = ulist_next(parents, NULL);
+                ULIST_ITER_INIT(&uiter);
+                node = ulist_next(parents, &uiter);
                 ref->parent = node ? node->val : 0;
+                ref->inode_list =
+                        node ? (struct extent_inode_elem *)node->aux : 0;
 
                 /* additional parents require new refs being added here */
-                while ((node = ulist_next(parents, node))) {
+                while ((node = ulist_next(parents, &uiter))) {
                         new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS);
                         if (!new_ref) {
                                 ret = -ENOMEM;
@@ -237,6 +368,8 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
                         }
                         memcpy(new_ref, ref, sizeof(*ref));
                         new_ref->parent = node->val;
+                        new_ref->inode_list =
+                                        (struct extent_inode_elem *)node->aux;
                         list_add(&new_ref->list, &ref->list);
                 }
                 ulist_reinit(parents);
@@ -246,10 +379,65 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
         return ret;
 }
 
+static inline int ref_for_same_block(struct __prelim_ref *ref1,
+                                     struct __prelim_ref *ref2)
+{
+        if (ref1->level != ref2->level)
+                return 0;
+        if (ref1->root_id != ref2->root_id)
+                return 0;
+        if (ref1->key_for_search.type != ref2->key_for_search.type)
+                return 0;
+        if (ref1->key_for_search.objectid != ref2->key_for_search.objectid)
+                return 0;
+        if (ref1->key_for_search.offset != ref2->key_for_search.offset)
+                return 0;
+        if (ref1->parent != ref2->parent)
+                return 0;
+
+        return 1;
+}
+
+/*
+ * read tree blocks and add keys where required.
+ */
+static int __add_missing_keys(struct btrfs_fs_info *fs_info,
+                              struct list_head *head)
+{
+        struct list_head *pos;
+        struct extent_buffer *eb;
+
+        list_for_each(pos, head) {
+                struct __prelim_ref *ref;
+                ref = list_entry(pos, struct __prelim_ref, list);
+
+                if (ref->parent)
+                        continue;
+                if (ref->key_for_search.type)
+                        continue;
+                BUG_ON(!ref->wanted_disk_byte);
+                eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
+                                     fs_info->tree_root->leafsize, 0);
+                BUG_ON(!eb);
+                btrfs_tree_read_lock(eb);
+                if (btrfs_header_level(eb) == 0)
+                        btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
+                else
+                        btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
+                btrfs_tree_read_unlock(eb);
+                free_extent_buffer(eb);
+        }
+        return 0;
+}
+
 /*
  * merge two lists of backrefs and adjust counts accordingly
  *
  * mode = 1: merge identical keys, if key is set
+ *    FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
+ *           additionally, we could even add a key range for the blocks we
+ *           looked into to merge even more (-> replace unresolved refs by those
+ *           having a parent).
  * mode = 2: merge identical parents
  */
 static int __merge_refs(struct list_head *head, int mode)
@@ -263,20 +451,21 @@ static int __merge_refs(struct list_head *head, int mode)
 
                 ref1 = list_entry(pos1, struct __prelim_ref, list);
 
-                if (mode == 1 && ref1->key.type == 0)
-                        continue;
                 for (pos2 = pos1->next, n2 = pos2->next; pos2 != head;
                      pos2 = n2, n2 = pos2->next) {
                         struct __prelim_ref *ref2;
+                        struct __prelim_ref *xchg;
 
                         ref2 = list_entry(pos2, struct __prelim_ref, list);
 
                         if (mode == 1) {
-                                if (memcmp(&ref1->key, &ref2->key,
-                                           sizeof(ref1->key)) ||
-                                    ref1->level != ref2->level ||
-                                    ref1->root_id != ref2->root_id)
+                                if (!ref_for_same_block(ref1, ref2))
                                         continue;
+                                if (!ref1->parent && ref2->parent) {
+                                        xchg = ref1;
+                                        ref1 = ref2;
+                                        ref2 = xchg;
+                                }
                                 ref1->count += ref2->count;
                         } else {
                                 if (ref1->parent != ref2->parent)
@@ -296,16 +485,17 @@ static int __merge_refs(struct list_head *head, int mode)
  * smaller or equal that seq to the list
  */
 static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
-                              struct btrfs_key *info_key,
                               struct list_head *prefs)
 {
         struct btrfs_delayed_extent_op *extent_op = head->extent_op;
         struct rb_node *n = &head->node.rb_node;
+        struct btrfs_key key;
+        struct btrfs_key op_key = {0};
         int sgn;
         int ret = 0;
 
         if (extent_op && extent_op->update_key)
-                btrfs_disk_key_to_cpu(info_key, &extent_op->key);
+                btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
 
         while ((n = rb_prev(n))) {
                 struct btrfs_delayed_ref_node *node;
@@ -337,7 +527,7 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
                         struct btrfs_delayed_tree_ref *ref;
 
                         ref = btrfs_delayed_node_to_tree_ref(node);
-                        ret = __add_prelim_ref(prefs, ref->root, info_key,
+                        ret = __add_prelim_ref(prefs, ref->root, &op_key,
                                                ref->level + 1, 0, node->bytenr,
                                                node->ref_mod * sgn);
                         break;
@@ -346,7 +536,7 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
                         struct btrfs_delayed_tree_ref *ref;
 
                         ref = btrfs_delayed_node_to_tree_ref(node);
-                        ret = __add_prelim_ref(prefs, ref->root, info_key,
+                        ret = __add_prelim_ref(prefs, ref->root, NULL,
                                                ref->level + 1, ref->parent,
                                                node->bytenr,
                                                node->ref_mod * sgn);
@@ -354,8 +544,6 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
                 }
                 case BTRFS_EXTENT_DATA_REF_KEY: {
                         struct btrfs_delayed_data_ref *ref;
-                        struct btrfs_key key;
-
                         ref = btrfs_delayed_node_to_data_ref(node);
 
                         key.objectid = ref->objectid;
@@ -368,7 +556,6 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
                 }
                 case BTRFS_SHARED_DATA_REF_KEY: {
                         struct btrfs_delayed_data_ref *ref;
-                        struct btrfs_key key;
 
                         ref = btrfs_delayed_node_to_data_ref(node);
 
@@ -394,8 +581,7 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
  */
 static int __add_inline_refs(struct btrfs_fs_info *fs_info,
                              struct btrfs_path *path, u64 bytenr,
-                             struct btrfs_key *info_key, int *info_level,
-                             struct list_head *prefs)
+                             int *info_level, struct list_head *prefs)
 {
         int ret = 0;
         int slot;
@@ -411,7 +597,7 @@ static int __add_inline_refs(struct btrfs_fs_info *fs_info,
          * enumerate all inline refs
          */
         leaf = path->nodes[0];
-        slot = path->slots[0] - 1;
+        slot = path->slots[0];
 
         item_size = btrfs_item_size_nr(leaf, slot);
         BUG_ON(item_size < sizeof(*ei));
@@ -424,12 +610,9 @@ static int __add_inline_refs(struct btrfs_fs_info *fs_info,
 
         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
                 struct btrfs_tree_block_info *info;
-                struct btrfs_disk_key disk_key;
 
                 info = (struct btrfs_tree_block_info *)ptr;
                 *info_level = btrfs_tree_block_level(leaf, info);
-                btrfs_tree_block_key(leaf, info, &disk_key);
-                btrfs_disk_key_to_cpu(info_key, &disk_key);
                 ptr += sizeof(struct btrfs_tree_block_info);
                 BUG_ON(ptr > end);
         } else {
@@ -447,7 +630,7 @@ static int __add_inline_refs(struct btrfs_fs_info *fs_info,
 
                 switch (type) {
                 case BTRFS_SHARED_BLOCK_REF_KEY:
-                        ret = __add_prelim_ref(prefs, 0, info_key,
+                        ret = __add_prelim_ref(prefs, 0, NULL,
                                                 *info_level + 1, offset,
                                                 bytenr, 1);
                         break;
@@ -462,8 +645,9 @@ static int __add_inline_refs(struct btrfs_fs_info *fs_info,
                         break;
                 }
                 case BTRFS_TREE_BLOCK_REF_KEY:
-                        ret = __add_prelim_ref(prefs, offset, info_key,
-                                               *info_level + 1, 0, bytenr, 1);
+                        ret = __add_prelim_ref(prefs, offset, NULL,
+                                               *info_level + 1, 0,
+                                               bytenr, 1);
                         break;
                 case BTRFS_EXTENT_DATA_REF_KEY: {
                         struct btrfs_extent_data_ref *dref;
@@ -477,8 +661,8 @@ static int __add_inline_refs(struct btrfs_fs_info *fs_info,
                         key.type = BTRFS_EXTENT_DATA_KEY;
                         key.offset = btrfs_extent_data_ref_offset(leaf, dref);
                         root = btrfs_extent_data_ref_root(leaf, dref);
-                        ret = __add_prelim_ref(prefs, root, &key, 0, 0, bytenr,
-                                                count);
+                        ret = __add_prelim_ref(prefs, root, &key, 0, 0,
+                                               bytenr, count);
                         break;
                 }
                 default:
@@ -496,8 +680,7 @@ static int __add_inline_refs(struct btrfs_fs_info *fs_info,
  */
 static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
                             struct btrfs_path *path, u64 bytenr,
-                            struct btrfs_key *info_key, int info_level,
-                            struct list_head *prefs)
+                            int info_level, struct list_head *prefs)
 {
         struct btrfs_root *extent_root = fs_info->extent_root;
         int ret;
@@ -527,7 +710,7 @@ static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
 
                 switch (key.type) {
                 case BTRFS_SHARED_BLOCK_REF_KEY:
-                        ret = __add_prelim_ref(prefs, 0, info_key,
+                        ret = __add_prelim_ref(prefs, 0, NULL,
                                                 info_level + 1, key.offset,
                                                 bytenr, 1);
                         break;
@@ -543,8 +726,9 @@ static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
                         break;
                 }
                 case BTRFS_TREE_BLOCK_REF_KEY:
-                        ret = __add_prelim_ref(prefs, key.offset, info_key,
-                                                info_level + 1, 0, bytenr, 1);
+                        ret = __add_prelim_ref(prefs, key.offset, NULL,
+                                               info_level + 1, 0,
+                                               bytenr, 1);
                         break;
                 case BTRFS_EXTENT_DATA_REF_KEY: {
                         struct btrfs_extent_data_ref *dref;
@@ -560,7 +744,7 @@ static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
                         key.offset = btrfs_extent_data_ref_offset(leaf, dref);
                         root = btrfs_extent_data_ref_root(leaf, dref);
                         ret = __add_prelim_ref(prefs, root, &key, 0, 0,
-                                                bytenr, count);
+                                               bytenr, count);
                         break;
                 }
                 default:
@@ -582,11 +766,12 @@ 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 delayed_ref_seq, u64 time_seq,
+                             struct ulist *refs, struct ulist *roots,
+                             const u64 *extent_item_pos)
 {
         struct btrfs_key key;
         struct btrfs_path *path;
-        struct btrfs_key info_key = { 0 };
         struct btrfs_delayed_ref_root *delayed_refs = NULL;
         struct btrfs_delayed_ref_head *head;
         int info_level = 0;
@@ -645,7 +830,7 @@ again:
                                 btrfs_put_delayed_ref(&head->node);
                                 goto again;
                         }
-                        ret = __add_delayed_refs(head, seq, &info_key,
+                        ret = __add_delayed_refs(head, delayed_ref_seq,
                                                  &prefs_delayed);
                         if (ret) {
                                 spin_unlock(&delayed_refs->lock);
@@ -659,16 +844,17 @@ again:
                 struct extent_buffer *leaf;
                 int slot;
 
+                path->slots[0]--;
                 leaf = path->nodes[0];
-                slot = path->slots[0] - 1;
+                slot = path->slots[0];
                 btrfs_item_key_to_cpu(leaf, &key, slot);
                 if (key.objectid == bytenr &&
                     key.type == BTRFS_EXTENT_ITEM_KEY) {
                         ret = __add_inline_refs(fs_info, path, bytenr,
-                                                &info_key, &info_level, &prefs);
+                                                &info_level, &prefs);
                         if (ret)
                                 goto out;
-                        ret = __add_keyed_refs(fs_info, path, bytenr, &info_key,
+                        ret = __add_keyed_refs(fs_info, path, bytenr,
                                                info_level, &prefs);
                         if (ret)
                                 goto out;
@@ -676,21 +862,18 @@ again:
         }
         btrfs_release_path(path);
 
-        /*
-         * when adding the delayed refs above, the info_key might not have
-         * been known yet. Go over the list and replace the missing keys
-         */
-        list_for_each_entry(ref, &prefs_delayed, list) {
-                if ((ref->key.offset | ref->key.type | ref->key.objectid) == 0)
-                        memcpy(&ref->key, &info_key, sizeof(ref->key));
-        }
         list_splice_init(&prefs_delayed, &prefs);
 
+        ret = __add_missing_keys(fs_info, &prefs);
+        if (ret)
+                goto out;
+
         ret = __merge_refs(&prefs, 1);
         if (ret)
                 goto out;
 
-        ret = __resolve_indirect_refs(fs_info, search_commit_root, &prefs);
+        ret = __resolve_indirect_refs(fs_info, search_commit_root, time_seq,
+                                      &prefs, extent_item_pos);
         if (ret)
                 goto out;
 
@@ -709,7 +892,33 @@ 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 && !ref->inode_list) {
+                                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);
+                                ref->inode_list = eie;
+                                free_extent_buffer(eb);
+                        }
+                        ret = ulist_add_merge(refs, ref->parent,
+                                              (unsigned long)ref->inode_list,
+                                              (unsigned long *)&eie, GFP_NOFS);
+                        if (!ret && extent_item_pos) {
+                                /*
+                                 * we've recorded that parent, so we must extend
+                                 * its inode list here
+                                 */
+                                BUG_ON(!eie);
+                                while (eie->next)
+                                        eie = eie->next;
+                                eie->next = ref->inode_list;
+                        }
                         BUG_ON(ret < 0);
                 }
                 kfree(ref);
@@ -734,6 +943,28 @@ 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
@@ -744,7 +975,9 @@ 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 delayed_ref_seq, u64 time_seq,
+                                struct ulist **leafs,
+                                const u64 *extent_item_pos)
 {
         struct ulist *tmp;
         int ret;
@@ -758,11 +991,12 @@ 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, delayed_ref_seq,
+                                time_seq, *leafs, tmp, extent_item_pos);
         ulist_free(tmp);
 
         if (ret < 0 && ret != -ENOENT) {
-                ulist_free(*leafs);
+                free_leaf_list(*leafs);
                 return ret;
         }
 
@@ -784,10 +1018,12 @@ 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 delayed_ref_seq, u64 time_seq,
+                                struct ulist **roots)
 {
         struct ulist *tmp;
         struct ulist_node *node = NULL;
+        struct ulist_iterator uiter;
         int ret;
 
         tmp = ulist_alloc(GFP_NOFS);
@@ -799,15 +1035,16 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
                 return -ENOMEM;
         }
 
+        ULIST_ITER_INIT(&uiter);
         while (1) {
-                ret = find_parent_nodes(trans, fs_info, bytenr, seq,
-                                        tmp, *roots);
+                ret = find_parent_nodes(trans, fs_info, bytenr, delayed_ref_seq,
+                                        time_seq, tmp, *roots, NULL);
                 if (ret < 0 && ret != -ENOENT) {
                         ulist_free(tmp);
                         ulist_free(*roots);
                         return ret;
                 }
-                node = ulist_next(tmp, node);
+                node = ulist_next(tmp, &uiter);
                 if (!node)
                         break;
                 bytenr = node->val;
@@ -1093,67 +1330,25 @@ 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;
 }
 
@@ -1175,7 +1370,10 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
         struct ulist *roots = NULL;
         struct ulist_node *ref_node = NULL;
         struct ulist_node *root_node = NULL;
-        struct seq_list seq_elem;
+        struct seq_list seq_elem = {};
+        struct seq_list tree_mod_seq_elem = {};
+        struct ulist_iterator ref_uiter;
+        struct ulist_iterator root_uiter;
         struct btrfs_delayed_ref_root *delayed_refs = NULL;
 
         pr_debug("resolving all inodes for extent %llu\n",
@@ -1192,34 +1390,41 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
                 spin_lock(&delayed_refs->lock);
                 btrfs_get_delayed_seq(delayed_refs, &seq_elem);
                 spin_unlock(&delayed_refs->lock);
+                btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
         }
 
         ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
-                                   extent_item_pos, seq_elem.seq,
-                                   &refs);
-
+                                   seq_elem.seq, tree_mod_seq_elem.seq, &refs,
+                                   &extent_item_pos);
         if (ret)
                 goto out;
 
-        while (!ret && (ref_node = ulist_next(refs, ref_node))) {
-                ret = btrfs_find_all_roots(trans, fs_info, ref_node->val, -1,
-                                                seq_elem.seq, &roots);
+        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,
+                                                seq_elem.seq,
+                                                tree_mod_seq_elem.seq, &roots);
                 if (ret)
                         break;
-                while (!ret && (root_node = ulist_next(roots, root_node))) {
-                        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);
+                ULIST_ITER_INIT(&root_uiter);
+                while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
+                        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) {
+                btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
                 btrfs_put_delayed_seq(delayed_refs, &seq_elem);
                 btrfs_end_transaction(trans, fs_info->extent_root);
         }