btrfs-progs: check: introduce function to check dir_item
[platform/upstream/btrfs-progs.git] / cmds-check.c
index 907d60c..dd8926d 100644 (file)
@@ -41,6 +41,7 @@
 #include "rbtree-utils.h"
 #include "backref.h"
 #include "ulist.h"
+#include "hash.h"
 
 enum task_position {
        TASK_EXTENTS,
@@ -185,9 +186,9 @@ struct inode_backref {
        unsigned int found_dir_item:1;
        unsigned int found_dir_index:1;
        unsigned int found_inode_ref:1;
-       unsigned int filetype:8;
+       u8 filetype;
+       u8 ref_type;
        int errors;
-       unsigned int ref_type;
        u64 dir;
        u64 index;
        u16 namelen;
@@ -936,7 +937,7 @@ static void maybe_free_inode_rec(struct cache_tree *inode_cache,
        struct cache_extent *cache;
        struct inode_backref *tmp, *backref;
        struct ptr_node *node;
-       unsigned char filetype;
+       u8 filetype;
 
        if (!rec->found_inode_item)
                return;
@@ -1067,7 +1068,7 @@ static struct inode_backref *get_inode_backref(struct inode_record *rec,
 static int add_inode_backref(struct cache_tree *inode_cache,
                             u64 ino, u64 dir, u64 index,
                             const char *name, int namelen,
-                            int filetype, int itemtype, int errors)
+                            u8 filetype, u8 itemtype, int errors)
 {
        struct inode_record *rec;
        struct inode_backref *backref;
@@ -1470,7 +1471,7 @@ static int process_dir_item(struct btrfs_root *root,
        u32 data_len;
        int error;
        int nritems = 0;
-       int filetype;
+       u8 filetype;
        struct btrfs_dir_item *di;
        struct inode_record *rec;
        struct cache_tree *root_cache;
@@ -2186,7 +2187,7 @@ static int add_missing_dir_index(struct btrfs_root *root,
                                 struct inode_record *rec,
                                 struct inode_backref *backref)
 {
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct btrfs_trans_handle *trans;
        struct btrfs_dir_item *dir_item;
        struct extent_buffer *leaf;
@@ -2197,27 +2198,22 @@ static int add_missing_dir_index(struct btrfs_root *root,
        u32 data_size = sizeof(*dir_item) + backref->namelen;
        int ret;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
        trans = btrfs_start_transaction(root, 1);
-       if (IS_ERR(trans)) {
-               btrfs_free_path(path);
+       if (IS_ERR(trans))
                return PTR_ERR(trans);
-       }
 
        fprintf(stderr, "repairing missing dir index item for inode %llu\n",
                (unsigned long long)rec->ino);
+
+       btrfs_init_path(&path);
        key.objectid = backref->dir;
        key.type = BTRFS_DIR_INDEX_KEY;
        key.offset = backref->index;
-
-       ret = btrfs_insert_empty_item(trans, root, path, &key, data_size);
+       ret = btrfs_insert_empty_item(trans, root, &path, &key, data_size);
        BUG_ON(ret);
 
-       leaf = path->nodes[0];
-       dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
+       leaf = path.nodes[0];
+       dir_item = btrfs_item_ptr(leaf, path.slots[0], struct btrfs_dir_item);
 
        disk_key.objectid = cpu_to_le64(rec->ino);
        disk_key.type = BTRFS_INODE_ITEM_KEY;
@@ -2230,7 +2226,7 @@ static int add_missing_dir_index(struct btrfs_root *root,
        name_ptr = (unsigned long)(dir_item + 1);
        write_extent_buffer(leaf, backref->name, name_ptr, backref->namelen);
        btrfs_mark_buffer_dirty(leaf);
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        btrfs_commit_transaction(trans, root);
 
        backref->found_dir_index = 1;
@@ -2255,31 +2251,25 @@ static int delete_dir_index(struct btrfs_root *root,
 {
        struct btrfs_trans_handle *trans;
        struct btrfs_dir_item *di;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        int ret = 0;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
        trans = btrfs_start_transaction(root, 1);
-       if (IS_ERR(trans)) {
-               btrfs_free_path(path);
+       if (IS_ERR(trans))
                return PTR_ERR(trans);
-       }
-
 
        fprintf(stderr, "Deleting bad dir index [%llu,%u,%llu] root %llu\n",
                (unsigned long long)backref->dir,
                BTRFS_DIR_INDEX_KEY, (unsigned long long)backref->index,
                (unsigned long long)root->objectid);
 
-       di = btrfs_lookup_dir_index(trans, root, path, backref->dir,
+       btrfs_init_path(&path);
+       di = btrfs_lookup_dir_index(trans, root, &path, backref->dir,
                                    backref->name, backref->namelen,
                                    backref->index, -1);
        if (IS_ERR(di)) {
                ret = PTR_ERR(di);
-               btrfs_free_path(path);
+               btrfs_release_path(&path);
                btrfs_commit_transaction(trans, root);
                if (ret == -ENOENT)
                        return 0;
@@ -2287,11 +2277,11 @@ static int delete_dir_index(struct btrfs_root *root,
        }
 
        if (!di)
-               ret = btrfs_del_item(trans, root, path);
+               ret = btrfs_del_item(trans, root, &path);
        else
-               ret = btrfs_delete_one_dir_name(trans, root, path, di);
+               ret = btrfs_delete_one_dir_name(trans, root, &path, di);
        BUG_ON(ret);
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        btrfs_commit_transaction(trans, root);
        return ret;
 }
@@ -2694,48 +2684,46 @@ out:
  */
 static int find_normal_file_extent(struct btrfs_root *root, u64 ino)
 {
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct btrfs_key key;
        struct btrfs_key found_key;
        struct btrfs_file_extent_item *fi;
        u8 type;
        int ret = 0;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               goto out;
+       btrfs_init_path(&path);
        key.objectid = ino;
        key.type = BTRFS_EXTENT_DATA_KEY;
        key.offset = 0;
 
-       ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+       ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
        if (ret < 0) {
                ret = 0;
                goto out;
        }
-       if (ret && path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
-               ret = btrfs_next_leaf(root, path);
+       if (ret && path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
+               ret = btrfs_next_leaf(root, &path);
                if (ret) {
                        ret = 0;
                        goto out;
                }
        }
        while (1) {
-               btrfs_item_key_to_cpu(path->nodes[0], &found_key,
-                                     path->slots[0]);
+               btrfs_item_key_to_cpu(path.nodes[0], &found_key,
+                                     path.slots[0]);
                if (found_key.objectid != ino ||
                    found_key.type != BTRFS_EXTENT_DATA_KEY)
                        break;
-               fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
+               fi = btrfs_item_ptr(path.nodes[0], path.slots[0],
                                    struct btrfs_file_extent_item);
-               type = btrfs_file_extent_type(path->nodes[0], fi);
+               type = btrfs_file_extent_type(path.nodes[0], fi);
                if (type != BTRFS_FILE_EXTENT_INLINE) {
                        ret = 1;
                        goto out;
                }
        }
 out:
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return ret;
 }
 
@@ -2926,7 +2914,7 @@ out:
 static int try_repair_inode(struct btrfs_root *root, struct inode_record *rec)
 {
        struct btrfs_trans_handle *trans;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        int ret = 0;
 
        if (!(rec->errors & (I_ERR_DIR_ISIZE_WRONG |
@@ -2938,10 +2926,6 @@ static int try_repair_inode(struct btrfs_root *root, struct inode_record *rec)
                             I_ERR_FILE_NBYTES_WRONG)))
                return rec->errors;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
        /*
         * For nlink repair, it may create a dir and add link, so
         * 2 for parent(256)'s dir_index and dir_item
@@ -2950,27 +2934,26 @@ static int try_repair_inode(struct btrfs_root *root, struct inode_record *rec)
         * 2 for lost+found dir's dir_index and dir_item for the file
         */
        trans = btrfs_start_transaction(root, 7);
-       if (IS_ERR(trans)) {
-               btrfs_free_path(path);
+       if (IS_ERR(trans))
                return PTR_ERR(trans);
-       }
 
+       btrfs_init_path(&path);
        if (rec->errors & I_ERR_NO_INODE_ITEM)
-               ret = repair_inode_no_item(trans, root, path, rec);
+               ret = repair_inode_no_item(trans, root, &path, rec);
        if (!ret && rec->errors & I_ERR_FILE_EXTENT_ORPHAN)
-               ret = repair_inode_orphan_extent(trans, root, path, rec);
+               ret = repair_inode_orphan_extent(trans, root, &path, rec);
        if (!ret && rec->errors & I_ERR_FILE_EXTENT_DISCOUNT)
-               ret = repair_inode_discount_extent(trans, root, path, rec);
+               ret = repair_inode_discount_extent(trans, root, &path, rec);
        if (!ret && rec->errors & I_ERR_DIR_ISIZE_WRONG)
-               ret = repair_inode_isize(trans, root, path, rec);
+               ret = repair_inode_isize(trans, root, &path, rec);
        if (!ret && rec->errors & I_ERR_NO_ORPHAN_ITEM)
-               ret = repair_inode_orphan_item(trans, root, path, rec);
+               ret = repair_inode_orphan_item(trans, root, &path, rec);
        if (!ret && rec->errors & I_ERR_LINK_COUNT_WRONG)
-               ret = repair_inode_nlinks(trans, root, path, rec);
+               ret = repair_inode_nlinks(trans, root, &path, rec);
        if (!ret && rec->errors & I_ERR_FILE_NBYTES_WRONG)
-               ret = repair_inode_nbytes(trans, root, path, rec);
+               ret = repair_inode_nbytes(trans, root, &path, rec);
        btrfs_commit_transaction(trans, root);
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return ret;
 }
 
@@ -3503,7 +3486,7 @@ static int repair_btree(struct btrfs_root *root,
                        struct cache_tree *corrupt_blocks)
 {
        struct btrfs_trans_handle *trans;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct btrfs_corrupt_block *corrupt;
        struct cache_extent *cache;
        struct btrfs_key key;
@@ -3514,23 +3497,20 @@ static int repair_btree(struct btrfs_root *root,
        if (cache_tree_empty(corrupt_blocks))
                return 0;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
        trans = btrfs_start_transaction(root, 1);
        if (IS_ERR(trans)) {
                ret = PTR_ERR(trans);
                fprintf(stderr, "Error starting transaction: %s\n",
                        strerror(-ret));
-               goto out_free_path;
+               return ret;
        }
+       btrfs_init_path(&path);
        cache = first_cache_extent(corrupt_blocks);
        while (cache) {
                corrupt = container_of(cache, struct btrfs_corrupt_block,
                                       cache);
                level = corrupt->level;
-               path->lowest_level = level;
+               path.lowest_level = level;
                key.objectid = corrupt->key.objectid;
                key.type = corrupt->key.type;
                key.offset = corrupt->key.offset;
@@ -3541,22 +3521,22 @@ static int repair_btree(struct btrfs_root *root,
                 * so ins_len set to 0 here.
                 * Balance will be done after all corrupt node/leaf is deleted.
                 */
-               ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+               ret = btrfs_search_slot(trans, root, &key, &path, 0, 1);
                if (ret < 0)
                        goto out;
-               offset = btrfs_node_blockptr(path->nodes[level],
-                                            path->slots[level]);
+               offset = btrfs_node_blockptr(path.nodes[level],
+                                            path.slots[level]);
 
                /* Remove the ptr */
-               ret = btrfs_del_ptr(trans, root, path, level,
-                                   path->slots[level]);
+               ret = btrfs_del_ptr(trans, root, &path, level,
+                                   path.slots[level]);
                if (ret < 0)
                        goto out;
                /*
                 * Remove the corresponding extent
                 * return value is not concerned.
                 */
-               btrfs_release_path(path);
+               btrfs_release_path(&path);
                ret = btrfs_free_extent(trans, root, offset, root->nodesize,
                                        0, root->root_key.objectid,
                                        level - 1, 0);
@@ -3569,18 +3549,17 @@ static int repair_btree(struct btrfs_root *root,
                corrupt = container_of(cache, struct btrfs_corrupt_block,
                                       cache);
                memcpy(&key, &corrupt->key, sizeof(key));
-               ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+               ret = btrfs_search_slot(trans, root, &key, &path, -1, 1);
                if (ret < 0)
                        goto out;
                /* return will always >0 since it won't find the item */
                ret = 0;
-               btrfs_release_path(path);
+               btrfs_release_path(&path);
                cache = next_cache_extent(cache);
        }
 out:
        btrfs_commit_transaction(trans, root);
-out_free_path:
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return ret;
 }
 
@@ -3848,6 +3827,572 @@ out:
        return err;
 }
 
+#define ROOT_DIR_ERROR         (1<<1)  /* bad ROOT_DIR */
+#define DIR_ITEM_MISSING       (1<<2)  /* DIR_ITEM not found */
+#define DIR_ITEM_MISMATCH      (1<<3)  /* DIR_ITEM found but not match */
+#define INODE_REF_MISSING      (1<<4)  /* INODE_REF/INODE_EXTREF not found */
+#define INODE_ITEM_MISSING     (1<<5)  /* INODE_ITEM not found */
+#define INODE_ITEM_MISMATCH    (1<<6)  /* INODE_ITEM found but not match */
+
+/*
+ * Find DIR_ITEM/DIR_INDEX for the given key and check it with the specified
+ * INODE_REF/INODE_EXTREF match.
+ *
+ * @root:      the root of the fs/file tree
+ * @ref_key:   the key of the INODE_REF/INODE_EXTREF
+ * @key:       the key of the DIR_ITEM/DIR_INDEX
+ * @index:     the index in the INODE_REF/INODE_EXTREF, be used to
+ *             distinguish root_dir between normal dir/file
+ * @name:      the name in the INODE_REF/INODE_EXTREF
+ * @namelen:   the length of name in the INODE_REF/INODE_EXTREF
+ * @mode:      the st_mode of INODE_ITEM
+ *
+ * Return 0 if no error occurred.
+ * Return ROOT_DIR_ERROR if found DIR_ITEM/DIR_INDEX for root_dir.
+ * Return DIR_ITEM_MISSING if couldn't find DIR_ITEM/DIR_INDEX for normal
+ * dir/file.
+ * Return DIR_ITEM_MISMATCH if INODE_REF/INODE_EXTREF and DIR_ITEM/DIR_INDEX
+ * not match for normal dir/file.
+ */
+static int find_dir_item(struct btrfs_root *root, struct btrfs_key *ref_key,
+                        struct btrfs_key *key, u64 index, char *name,
+                        u32 namelen, u32 mode)
+{
+       struct btrfs_path path;
+       struct extent_buffer *node;
+       struct btrfs_dir_item *di;
+       struct btrfs_key location;
+       char namebuf[BTRFS_NAME_LEN] = {0};
+       u32 total;
+       u32 cur = 0;
+       u32 len;
+       u32 name_len;
+       u32 data_len;
+       u8 filetype;
+       int slot;
+       int ret;
+
+       btrfs_init_path(&path);
+       ret = btrfs_search_slot(NULL, root, key, &path, 0, 0);
+       if (ret < 0) {
+               ret = DIR_ITEM_MISSING;
+               goto out;
+       }
+
+       /* Process root dir and goto out*/
+       if (index == 0) {
+               if (ret == 0) {
+                       ret = ROOT_DIR_ERROR;
+                       error(
+                       "root %llu INODE %s[%llu %llu] ROOT_DIR shouldn't have %s",
+                               root->objectid,
+                               ref_key->type == BTRFS_INODE_REF_KEY ?
+                                       "REF" : "EXTREF",
+                               ref_key->objectid, ref_key->offset,
+                               key->type == BTRFS_DIR_ITEM_KEY ?
+                                       "DIR_ITEM" : "DIR_INDEX");
+               } else {
+                       ret = 0;
+               }
+
+               goto out;
+       }
+
+       /* Process normal file/dir */
+       if (ret > 0) {
+               ret = DIR_ITEM_MISSING;
+               error(
+               "root %llu INODE %s[%llu %llu] doesn't have related %s[%llu %llu] namelen %u filename %s filetype %d",
+                       root->objectid,
+                       ref_key->type == BTRFS_INODE_REF_KEY ? "REF" : "EXTREF",
+                       ref_key->objectid, ref_key->offset,
+                       key->type == BTRFS_DIR_ITEM_KEY ?
+                               "DIR_ITEM" : "DIR_INDEX",
+                       key->objectid, key->offset, namelen, name,
+                       imode_to_type(mode));
+               goto out;
+       }
+
+       /* Check whether inode_id/filetype/name match */
+       node = path.nodes[0];
+       slot = path.slots[0];
+       di = btrfs_item_ptr(node, slot, struct btrfs_dir_item);
+       total = btrfs_item_size_nr(node, slot);
+       while (cur < total) {
+               ret = DIR_ITEM_MISMATCH;
+               name_len = btrfs_dir_name_len(node, di);
+               data_len = btrfs_dir_data_len(node, di);
+
+               btrfs_dir_item_key_to_cpu(node, di, &location);
+               if (location.objectid != ref_key->objectid ||
+                   location.type !=  BTRFS_INODE_ITEM_KEY ||
+                   location.offset != 0)
+                       goto next;
+
+               filetype = btrfs_dir_type(node, di);
+               if (imode_to_type(mode) != filetype)
+                       goto next;
+
+               if (name_len <= BTRFS_NAME_LEN) {
+                       len = name_len;
+               } else {
+                       len = BTRFS_NAME_LEN;
+                       warning("root %llu %s[%llu %llu] name too long %u, trimmed",
+                       root->objectid,
+                       key->type == BTRFS_DIR_ITEM_KEY ?
+                       "DIR_ITEM" : "DIR_INDEX",
+                       key->objectid, key->offset, name_len);
+               }
+               read_extent_buffer(node, namebuf, (unsigned long)(di + 1), len);
+               if (len != namelen || strncmp(namebuf, name, len))
+                       goto next;
+
+               ret = 0;
+               goto out;
+next:
+               len = sizeof(*di) + name_len + data_len;
+               di = (struct btrfs_dir_item *)((char *)di + len);
+               cur += len;
+       }
+       if (ret == DIR_ITEM_MISMATCH)
+               error(
+               "root %llu INODE %s[%llu %llu] and %s[%llu %llu] mismatch namelen %u filename %s filetype %d",
+                       root->objectid,
+                       ref_key->type == BTRFS_INODE_REF_KEY ? "REF" : "EXTREF",
+                       ref_key->objectid, ref_key->offset,
+                       key->type == BTRFS_DIR_ITEM_KEY ?
+                               "DIR_ITEM" : "DIR_INDEX",
+                       key->objectid, key->offset, namelen, name,
+                       imode_to_type(mode));
+out:
+       btrfs_release_path(&path);
+       return ret;
+}
+
+/*
+ * Traverse the given INODE_REF and call find_dir_item() to find related
+ * DIR_ITEM/DIR_INDEX.
+ *
+ * @root:      the root of the fs/file tree
+ * @ref_key:   the key of the INODE_REF
+ * @refs:      the count of INODE_REF
+ * @mode:      the st_mode of INODE_ITEM
+ *
+ * Return 0 if no error occurred.
+ */
+static int check_inode_ref(struct btrfs_root *root, struct btrfs_key *ref_key,
+                          struct extent_buffer *node, int slot, u64 *refs,
+                          int mode)
+{
+       struct btrfs_key key;
+       struct btrfs_inode_ref *ref;
+       char namebuf[BTRFS_NAME_LEN] = {0};
+       u32 total;
+       u32 cur = 0;
+       u32 len;
+       u32 name_len;
+       u64 index;
+       int ret, err = 0;
+
+       ref = btrfs_item_ptr(node, slot, struct btrfs_inode_ref);
+       total = btrfs_item_size_nr(node, slot);
+
+next:
+       /* Update inode ref count */
+       (*refs)++;
+
+       index = btrfs_inode_ref_index(node, ref);
+       name_len = btrfs_inode_ref_name_len(node, ref);
+       if (name_len <= BTRFS_NAME_LEN) {
+               len = name_len;
+       } else {
+               len = BTRFS_NAME_LEN;
+               warning("root %llu INODE_REF[%llu %llu] name too long",
+                       root->objectid, ref_key->objectid, ref_key->offset);
+       }
+
+       read_extent_buffer(node, namebuf, (unsigned long)(ref + 1), len);
+
+       /* Check root dir ref name */
+       if (index == 0 && strncmp(namebuf, "..", name_len)) {
+               error("root %llu INODE_REF[%llu %llu] ROOT_DIR name shouldn't be %s",
+                     root->objectid, ref_key->objectid, ref_key->offset,
+                     namebuf);
+               err |= ROOT_DIR_ERROR;
+       }
+
+       /* Find related DIR_INDEX */
+       key.objectid = ref_key->offset;
+       key.type = BTRFS_DIR_INDEX_KEY;
+       key.offset = index;
+       ret = find_dir_item(root, ref_key, &key, index, namebuf, len, mode);
+       err |= ret;
+
+       /* Find related dir_item */
+       key.objectid = ref_key->offset;
+       key.type = BTRFS_DIR_ITEM_KEY;
+       key.offset = btrfs_name_hash(namebuf, len);
+       ret = find_dir_item(root, ref_key, &key, index, namebuf, len, mode);
+       err |= ret;
+
+       len = sizeof(*ref) + name_len;
+       ref = (struct btrfs_inode_ref *)((char *)ref + len);
+       cur += len;
+       if (cur < total)
+               goto next;
+
+       return err;
+}
+
+/*
+ * Traverse the given INODE_EXTREF and call find_dir_item() to find related
+ * DIR_ITEM/DIR_INDEX.
+ *
+ * @root:      the root of the fs/file tree
+ * @ref_key:   the key of the INODE_EXTREF
+ * @refs:      the count of INODE_EXTREF
+ * @mode:      the st_mode of INODE_ITEM
+ *
+ * Return 0 if no error occurred.
+ */
+static int check_inode_extref(struct btrfs_root *root,
+                             struct btrfs_key *ref_key,
+                             struct extent_buffer *node, int slot, u64 *refs,
+                             int mode)
+{
+       struct btrfs_key key;
+       struct btrfs_inode_extref *extref;
+       char namebuf[BTRFS_NAME_LEN] = {0};
+       u32 total;
+       u32 cur = 0;
+       u32 len;
+       u32 name_len;
+       u64 index;
+       u64 parent;
+       int ret;
+       int err = 0;
+
+       extref = btrfs_item_ptr(node, slot, struct btrfs_inode_extref);
+       total = btrfs_item_size_nr(node, slot);
+
+next:
+       /* update inode ref count */
+       (*refs)++;
+       name_len = btrfs_inode_extref_name_len(node, extref);
+       index = btrfs_inode_extref_index(node, extref);
+       parent = btrfs_inode_extref_parent(node, extref);
+       if (name_len <= BTRFS_NAME_LEN) {
+               len = name_len;
+       } else {
+               len = BTRFS_NAME_LEN;
+               warning("root %llu INODE_EXTREF[%llu %llu] name too long",
+                       root->objectid, ref_key->objectid, ref_key->offset);
+       }
+       read_extent_buffer(node, namebuf, (unsigned long)(extref + 1), len);
+
+       /* Check root dir ref name */
+       if (index == 0 && strncmp(namebuf, "..", name_len)) {
+               error("root %llu INODE_EXTREF[%llu %llu] ROOT_DIR name shouldn't be %s",
+                     root->objectid, ref_key->objectid, ref_key->offset,
+                     namebuf);
+               err |= ROOT_DIR_ERROR;
+       }
+
+       /* find related dir_index */
+       key.objectid = parent;
+       key.type = BTRFS_DIR_INDEX_KEY;
+       key.offset = index;
+       ret = find_dir_item(root, ref_key, &key, index, namebuf, len, mode);
+       err |= ret;
+
+       /* find related dir_item */
+       key.objectid = parent;
+       key.type = BTRFS_DIR_ITEM_KEY;
+       key.offset = btrfs_name_hash(namebuf, len);
+       ret = find_dir_item(root, ref_key, &key, index, namebuf, len, mode);
+       err |= ret;
+
+       len = sizeof(*extref) + name_len;
+       extref = (struct btrfs_inode_extref *)((char *)extref + len);
+       cur += len;
+
+       if (cur < total)
+               goto next;
+
+       return err;
+}
+
+/*
+ * Find INODE_REF/INODE_EXTREF for the given key and check it with the specified
+ * DIR_ITEM/DIR_INDEX match.
+ *
+ * @root:      the root of the fs/file tree
+ * @key:       the key of the INODE_REF/INODE_EXTREF
+ * @name:      the name in the INODE_REF/INODE_EXTREF
+ * @namelen:   the length of name in the INODE_REF/INODE_EXTREF
+ * @index:     the index in the INODE_REF/INODE_EXTREF, for DIR_ITEM set index
+ * to (u64)-1
+ * @ext_ref:   the EXTENDED_IREF feature
+ *
+ * Return 0 if no error occurred.
+ * Return >0 for error bitmap
+ */
+static int find_inode_ref(struct btrfs_root *root, struct btrfs_key *key,
+                         char *name, int namelen, u64 index,
+                         unsigned int ext_ref)
+{
+       struct btrfs_path path;
+       struct btrfs_inode_ref *ref;
+       struct btrfs_inode_extref *extref;
+       struct extent_buffer *node;
+       char ref_namebuf[BTRFS_NAME_LEN] = {0};
+       u32 total;
+       u32 cur = 0;
+       u32 len;
+       u32 ref_namelen;
+       u64 ref_index;
+       u64 parent;
+       u64 dir_id;
+       int slot;
+       int ret;
+
+       btrfs_init_path(&path);
+       ret = btrfs_search_slot(NULL, root, key, &path, 0, 0);
+       if (ret) {
+               ret = INODE_REF_MISSING;
+               goto extref;
+       }
+
+       node = path.nodes[0];
+       slot = path.slots[0];
+
+       ref = btrfs_item_ptr(node, slot, struct btrfs_inode_ref);
+       total = btrfs_item_size_nr(node, slot);
+
+       /* Iterate all entry of INODE_REF */
+       while (cur < total) {
+               ret = INODE_REF_MISSING;
+
+               ref_namelen = btrfs_inode_ref_name_len(node, ref);
+               ref_index = btrfs_inode_ref_index(node, ref);
+               if (index != (u64)-1 && index != ref_index)
+                       goto next_ref;
+
+               if (ref_namelen <= BTRFS_NAME_LEN) {
+                       len = ref_namelen;
+               } else {
+                       len = BTRFS_NAME_LEN;
+                       warning("root %llu INODE %s[%llu %llu] name too long",
+                               root->objectid,
+                               key->type == BTRFS_INODE_REF_KEY ?
+                                       "REF" : "EXTREF",
+                               key->objectid, key->offset);
+               }
+               read_extent_buffer(node, ref_namebuf, (unsigned long)(ref + 1),
+                                  len);
+
+               if (len != namelen || strncmp(ref_namebuf, name, len))
+                       goto next_ref;
+
+               ret = 0;
+               goto out;
+next_ref:
+               len = sizeof(*ref) + ref_namelen;
+               ref = (struct btrfs_inode_ref *)((char *)ref + len);
+               cur += len;
+       }
+
+extref:
+       /* Skip if not support EXTENDED_IREF feature */
+       if (!ext_ref)
+               goto out;
+
+       btrfs_release_path(&path);
+       btrfs_init_path(&path);
+
+       dir_id = key->offset;
+       key->type = BTRFS_INODE_EXTREF_KEY;
+       key->offset = btrfs_extref_hash(dir_id, name, namelen);
+
+       ret = btrfs_search_slot(NULL, root, key, &path, 0, 0);
+       if (ret) {
+               ret = INODE_REF_MISSING;
+               goto out;
+       }
+
+       node = path.nodes[0];
+       slot = path.slots[0];
+
+       extref = btrfs_item_ptr(node, slot, struct btrfs_inode_extref);
+       cur = 0;
+       total = btrfs_item_size_nr(node, slot);
+
+       /* Iterate all entry of INODE_EXTREF */
+       while (cur < total) {
+               ret = INODE_REF_MISSING;
+
+               ref_namelen = btrfs_inode_extref_name_len(node, extref);
+               ref_index = btrfs_inode_extref_index(node, extref);
+               parent = btrfs_inode_extref_parent(node, extref);
+               if (index != (u64)-1 && index != ref_index)
+                       goto next_extref;
+
+               if (parent != dir_id)
+                       goto next_extref;
+
+               if (ref_namelen <= BTRFS_NAME_LEN) {
+                       len = ref_namelen;
+               } else {
+                       len = BTRFS_NAME_LEN;
+                       warning("Warning: root %llu INODE %s[%llu %llu] name too long\n",
+                               root->objectid,
+                               key->type == BTRFS_INODE_REF_KEY ?
+                                       "REF" : "EXTREF",
+                               key->objectid, key->offset);
+               }
+               read_extent_buffer(node, ref_namebuf,
+                                  (unsigned long)(extref + 1), len);
+
+               if (len != namelen || strncmp(ref_namebuf, name, len))
+                       goto next_extref;
+
+               ret = 0;
+               goto out;
+
+next_extref:
+               len = sizeof(*extref) + ref_namelen;
+               extref = (struct btrfs_inode_extref *)((char *)extref + len);
+               cur += len;
+
+       }
+out:
+       btrfs_release_path(&path);
+       return ret;
+}
+
+/*
+ * Traverse the given DIR_ITEM/DIR_INDEX and check related INODE_ITEM and
+ * call find_inode_ref() to check related INODE_REF/INODE_EXTREF.
+ *
+ * @root:      the root of the fs/file tree
+ * @key:       the key of the INODE_REF/INODE_EXTREF
+ * @size:      the st_size of the INODE_ITEM
+ * @ext_ref:   the EXTENDED_IREF feature
+ *
+ * Return 0 if no error occurred.
+ */
+static int check_dir_item(struct btrfs_root *root, struct btrfs_key *key,
+                         struct extent_buffer *node, int slot, u64 *size,
+                         unsigned int ext_ref)
+{
+       struct btrfs_dir_item *di;
+       struct btrfs_inode_item *ii;
+       struct btrfs_path path;
+       struct btrfs_key location;
+       char namebuf[BTRFS_NAME_LEN] = {0};
+       u32 total;
+       u32 cur = 0;
+       u32 len;
+       u32 name_len;
+       u32 data_len;
+       u8 filetype;
+       u32 mode;
+       u64 index;
+       int ret;
+       int err = 0;
+
+       /*
+        * For DIR_ITEM set index to (u64)-1, so that find_inode_ref
+        * ignore index check.
+        */
+       index = (key->type == BTRFS_DIR_INDEX_KEY) ? key->offset : (u64)-1;
+
+       di = btrfs_item_ptr(node, slot, struct btrfs_dir_item);
+       total = btrfs_item_size_nr(node, slot);
+
+       while (cur < total) {
+               data_len = btrfs_dir_data_len(node, di);
+               if (data_len)
+                       error("root %llu %s[%llu %llu] data_len shouldn't be %u",
+                             root->objectid, key->type == BTRFS_DIR_ITEM_KEY ?
+                             "DIR_ITEM" : "DIR_INDEX",
+                             key->objectid, key->offset, data_len);
+
+               name_len = btrfs_dir_name_len(node, di);
+               if (name_len <= BTRFS_NAME_LEN) {
+                       len = name_len;
+               } else {
+                       len = BTRFS_NAME_LEN;
+                       warning("root %llu %s[%llu %llu] name too long",
+                               root->objectid,
+                               key->type == BTRFS_DIR_ITEM_KEY ?
+                               "DIR_ITEM" : "DIR_INDEX",
+                               key->objectid, key->offset);
+               }
+               (*size) += name_len;
+
+               read_extent_buffer(node, namebuf, (unsigned long)(di + 1), len);
+               filetype = btrfs_dir_type(node, di);
+
+               btrfs_init_path(&path);
+               btrfs_dir_item_key_to_cpu(node, di, &location);
+
+               /* Ignore related ROOT_ITEM check */
+               if (location.type == BTRFS_ROOT_ITEM_KEY)
+                       goto next;
+
+               /* Check relative INODE_ITEM(existence/filetype) */
+               ret = btrfs_search_slot(NULL, root, &location, &path, 0, 0);
+               if (ret) {
+                       err |= INODE_ITEM_MISSING;
+                       error("root %llu %s[%llu %llu] couldn't find relative INODE_ITEM[%llu] namelen %u filename %s filetype %x",
+                             root->objectid, key->type == BTRFS_DIR_ITEM_KEY ?
+                             "DIR_ITEM" : "DIR_INDEX", key->objectid,
+                             key->offset, location.objectid, name_len,
+                             namebuf, filetype);
+                       goto next;
+               }
+
+               ii = btrfs_item_ptr(path.nodes[0], path.slots[0],
+                                   struct btrfs_inode_item);
+               mode = btrfs_inode_mode(path.nodes[0], ii);
+
+               if (imode_to_type(mode) != filetype) {
+                       err |= INODE_ITEM_MISMATCH;
+                       error("root %llu %s[%llu %llu] relative INODE_ITEM filetype mismatch namelen %u filename %s filetype %d",
+                             root->objectid, key->type == BTRFS_DIR_ITEM_KEY ?
+                             "DIR_ITEM" : "DIR_INDEX", key->objectid,
+                             key->offset, name_len, namebuf, filetype);
+               }
+
+               /* Check relative INODE_REF/INODE_EXTREF */
+               location.type = BTRFS_INODE_REF_KEY;
+               location.offset = key->objectid;
+               ret = find_inode_ref(root, &location, namebuf, len,
+                                      index, ext_ref);
+               err |= ret;
+               if (ret & INODE_REF_MISSING)
+                       error("root %llu %s[%llu %llu] relative INODE_REF missing namelen %u filename %s filetype %d",
+                             root->objectid, key->type == BTRFS_DIR_ITEM_KEY ?
+                             "DIR_ITEM" : "DIR_INDEX", key->objectid,
+                             key->offset, name_len, namebuf, filetype);
+
+next:
+               btrfs_release_path(&path);
+               len = sizeof(*di) + name_len + data_len;
+               di = (struct btrfs_dir_item *)((char *)di + len);
+               cur += len;
+
+               if (key->type == BTRFS_DIR_INDEX_KEY && cur < total) {
+                       error("root %llu DIR_INDEX[%llu %llu] should contain only one entry",
+                             root->objectid, key->objectid, key->offset);
+                       break;
+               }
+       }
+
+       return err;
+}
+
 static int all_backpointers_checked(struct extent_record *rec, int print_errs)
 {
        struct list_head *cur = rec->backrefs.next;
@@ -4322,7 +4867,7 @@ static int try_to_fix_bad_block(struct btrfs_root *root,
        struct ulist *roots;
        struct ulist_node *node;
        struct btrfs_root *search_root;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct ulist_iterator iter;
        struct btrfs_key root_key, key;
        int ret;
@@ -4331,17 +4876,11 @@ static int try_to_fix_bad_block(struct btrfs_root *root,
            status != BTRFS_TREE_BLOCK_INVALID_OFFSETS)
                return -EIO;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -EIO;
-
-       ret = btrfs_find_all_roots(NULL, root->fs_info, buf->start,
-                                  0, &roots);
-       if (ret) {
-               btrfs_free_path(path);
+       ret = btrfs_find_all_roots(NULL, root->fs_info, buf->start, 0, &roots);
+       if (ret)
                return -EIO;
-       }
 
+       btrfs_init_path(&path);
        ULIST_ITER_INIT(&iter);
        while ((node = ulist_next(roots, &iter))) {
                root_key.objectid = node->val;
@@ -4361,31 +4900,31 @@ static int try_to_fix_bad_block(struct btrfs_root *root,
                        break;
                }
 
-               path->lowest_level = btrfs_header_level(buf);
-               path->skip_check_block = 1;
-               if (path->lowest_level)
+               path.lowest_level = btrfs_header_level(buf);
+               path.skip_check_block = 1;
+               if (path.lowest_level)
                        btrfs_node_key_to_cpu(buf, &key, 0);
                else
                        btrfs_item_key_to_cpu(buf, &key, 0);
-               ret = btrfs_search_slot(trans, search_root, &key, path, 0, 1);
+               ret = btrfs_search_slot(trans, search_root, &key, &path, 0, 1);
                if (ret) {
                        ret = -EIO;
                        btrfs_commit_transaction(trans, search_root);
                        break;
                }
                if (status == BTRFS_TREE_BLOCK_BAD_KEY_ORDER)
-                       ret = fix_key_order(trans, search_root, path);
+                       ret = fix_key_order(trans, search_root, &path);
                else if (status == BTRFS_TREE_BLOCK_INVALID_OFFSETS)
-                       ret = fix_item_offset(trans, search_root, path);
+                       ret = fix_item_offset(trans, search_root, &path);
                if (ret) {
                        btrfs_commit_transaction(trans, search_root);
                        break;
                }
-               btrfs_release_path(path);
+               btrfs_release_path(&path);
                btrfs_commit_transaction(trans, search_root);
        }
        ulist_free(roots);
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return ret;
 }
 
@@ -5568,31 +6107,27 @@ static int check_cache_range(struct btrfs_root *root,
 static int verify_space_cache(struct btrfs_root *root,
                              struct btrfs_block_group_cache *cache)
 {
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct extent_buffer *leaf;
        struct btrfs_key key;
        u64 last;
        int ret = 0;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
        root = root->fs_info->extent_root;
 
        last = max_t(u64, cache->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 
+       btrfs_init_path(&path);
        key.objectid = last;
        key.offset = 0;
        key.type = BTRFS_EXTENT_ITEM_KEY;
-
-       ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+       ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
        if (ret < 0)
                goto out;
        ret = 0;
        while (1) {
-               if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
-                       ret = btrfs_next_leaf(root, path);
+               if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
+                       ret = btrfs_next_leaf(root, &path);
                        if (ret < 0)
                                goto out;
                        if (ret > 0) {
@@ -5600,13 +6135,13 @@ static int verify_space_cache(struct btrfs_root *root,
                                break;
                        }
                }
-               leaf = path->nodes[0];
-               btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+               leaf = path.nodes[0];
+               btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
                if (key.objectid >= cache->key.offset + cache->key.objectid)
                        break;
                if (key.type != BTRFS_EXTENT_ITEM_KEY &&
                    key.type != BTRFS_METADATA_ITEM_KEY) {
-                       path->slots[0]++;
+                       path.slots[0]++;
                        continue;
                }
 
@@ -5615,7 +6150,7 @@ static int verify_space_cache(struct btrfs_root *root,
                                last = key.objectid + key.offset;
                        else
                                last = key.objectid + root->nodesize;
-                       path->slots[0]++;
+                       path.slots[0]++;
                        continue;
                }
 
@@ -5627,7 +6162,7 @@ static int verify_space_cache(struct btrfs_root *root,
                        last = key.objectid + key.offset;
                else
                        last = key.objectid + root->nodesize;
-               path->slots[0]++;
+               path.slots[0]++;
        }
 
        if (last < cache->key.objectid + cache->key.offset)
@@ -5636,7 +6171,7 @@ static int verify_space_cache(struct btrfs_root *root,
                                        cache->key.offset - last);
 
 out:
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
 
        if (!ret &&
            !RB_EMPTY_ROOT(&cache->free_space_ctl->free_space_offset)) {
@@ -5793,33 +6328,28 @@ out:
 static int check_extent_exists(struct btrfs_root *root, u64 bytenr,
                               u64 num_bytes)
 {
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct extent_buffer *leaf;
        struct btrfs_key key;
        int ret;
 
-       path = btrfs_alloc_path();
-       if (!path) {
-               fprintf(stderr, "Error allocating path\n");
-               return -ENOMEM;
-       }
-
+       btrfs_init_path(&path);
        key.objectid = bytenr;
        key.type = BTRFS_EXTENT_ITEM_KEY;
        key.offset = (u64)-1;
 
 again:
-       ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
+       ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, &path,
                                0, 0);
        if (ret < 0) {
                fprintf(stderr, "Error looking up extent record %d\n", ret);
-               btrfs_free_path(path);
+               btrfs_release_path(&path);
                return ret;
        } else if (ret) {
-               if (path->slots[0] > 0) {
-                       path->slots[0]--;
+               if (path.slots[0] > 0) {
+                       path.slots[0]--;
                } else {
-                       ret = btrfs_prev_leaf(root, path);
+                       ret = btrfs_prev_leaf(root, &path);
                        if (ret < 0) {
                                goto out;
                        } else if (ret > 0) {
@@ -5829,7 +6359,7 @@ again:
                }
        }
 
-       btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+       btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
 
        /*
         * Block group items come before extent items if they have the same
@@ -5840,10 +6370,10 @@ again:
         * EXTENT_ITEM_KEY please?
         */
        while (key.type > BTRFS_EXTENT_ITEM_KEY) {
-               if (path->slots[0] > 0) {
-                       path->slots[0]--;
+               if (path.slots[0] > 0) {
+                       path.slots[0]--;
                } else {
-                       ret = btrfs_prev_leaf(root, path);
+                       ret = btrfs_prev_leaf(root, &path);
                        if (ret < 0) {
                                goto out;
                        } else if (ret > 0) {
@@ -5851,29 +6381,29 @@ again:
                                goto out;
                        }
                }
-               btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+               btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
        }
 
        while (num_bytes) {
-               if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
-                       ret = btrfs_next_leaf(root, path);
+               if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
+                       ret = btrfs_next_leaf(root, &path);
                        if (ret < 0) {
                                fprintf(stderr, "Error going to next leaf "
                                        "%d\n", ret);
-                               btrfs_free_path(path);
+                               btrfs_release_path(&path);
                                return ret;
                        } else if (ret) {
                                break;
                        }
                }
-               leaf = path->nodes[0];
-               btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+               leaf = path.nodes[0];
+               btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
                if (key.type != BTRFS_EXTENT_ITEM_KEY) {
-                       path->slots[0]++;
+                       path.slots[0]++;
                        continue;
                }
                if (key.objectid + key.offset < bytenr) {
-                       path->slots[0]++;
+                       path.slots[0]++;
                        continue;
                }
                if (key.objectid > bytenr + num_bytes)
@@ -5906,7 +6436,7 @@ again:
                                 * in real life, but no harm in coding it up
                                 * anyway just in case.
                                 */
-                               btrfs_release_path(path);
+                               btrfs_release_path(&path);
                                ret = check_extent_exists(root, new_start,
                                                          new_bytes);
                                if (ret) {
@@ -5919,7 +6449,7 @@ again:
                        }
                        num_bytes = key.objectid - bytenr;
                }
-               path->slots[0]++;
+               path.slots[0]++;
        }
        ret = 0;
 
@@ -5930,13 +6460,13 @@ out:
                ret = 1;
        }
 
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return ret;
 }
 
 static int check_csums(struct btrfs_root *root)
 {
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct extent_buffer *leaf;
        struct btrfs_key key;
        u64 offset = 0, num_bytes = 0;
@@ -5952,28 +6482,24 @@ static int check_csums(struct btrfs_root *root)
                return -ENOENT;
        }
 
+       btrfs_init_path(&path);
        key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
        key.type = BTRFS_EXTENT_CSUM_KEY;
        key.offset = 0;
-
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
-       ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+       ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
        if (ret < 0) {
                fprintf(stderr, "Error searching csum tree %d\n", ret);
-               btrfs_free_path(path);
+               btrfs_release_path(&path);
                return ret;
        }
 
-       if (ret > 0 && path->slots[0])
-               path->slots[0]--;
+       if (ret > 0 && path.slots[0])
+               path.slots[0]--;
        ret = 0;
 
        while (1) {
-               if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
-                       ret = btrfs_next_leaf(root, path);
+               if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
+                       ret = btrfs_next_leaf(root, &path);
                        if (ret < 0) {
                                fprintf(stderr, "Error going to next leaf "
                                        "%d\n", ret);
@@ -5982,19 +6508,19 @@ static int check_csums(struct btrfs_root *root)
                        if (ret)
                                break;
                }
-               leaf = path->nodes[0];
+               leaf = path.nodes[0];
 
-               btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+               btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
                if (key.type != BTRFS_EXTENT_CSUM_KEY) {
-                       path->slots[0]++;
+                       path.slots[0]++;
                        continue;
                }
 
-               data_len = (btrfs_item_size_nr(leaf, path->slots[0]) /
+               data_len = (btrfs_item_size_nr(leaf, path.slots[0]) /
                              csum_size) * root->sectorsize;
                if (!check_data_csum)
                        goto skip_csum_check;
-               leaf_offset = btrfs_item_ptr_offset(leaf, path->slots[0]);
+               leaf_offset = btrfs_item_ptr_offset(leaf, path.slots[0]);
                ret = check_extent_csums(root, key.offset, data_len,
                                         leaf_offset, leaf);
                if (ret)
@@ -6014,10 +6540,10 @@ skip_csum_check:
                        num_bytes = 0;
                }
                num_bytes += data_len;
-               path->slots[0]++;
+               path.slots[0]++;
        }
 
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return errors;
 }
 
@@ -6711,7 +7237,6 @@ static int record_extent(struct btrfs_trans_handle *trans,
        struct extent_buffer *leaf;
        struct btrfs_key ins_key;
        struct btrfs_extent_item *ei;
-       struct tree_backref *tback;
        struct data_backref *dback;
        struct btrfs_tree_block_info *bi;
 
@@ -6747,7 +7272,6 @@ static int record_extent(struct btrfs_trans_handle *trans,
                } else {
                        struct btrfs_disk_key copy_key;;
 
-                       tback = to_tree_backref(back);
                        bi = (struct btrfs_tree_block_info *)(ei + 1);
                        memset_extent_buffer(leaf, 0, (unsigned long)bi,
                                             sizeof(*bi));
@@ -6813,6 +7337,7 @@ static int record_extent(struct btrfs_trans_handle *trans,
                                dback->found_ref);
        } else {
                u64 parent;
+               struct tree_backref *tback;
 
                tback = to_tree_backref(back);
                if (back->full_backref)
@@ -6850,11 +7375,6 @@ static struct extent_entry *find_most_right_entry(struct list_head *entries)
        struct extent_entry *entry, *best = NULL, *prev = NULL;
 
        list_for_each_entry(entry, entries, list) {
-               if (!prev) {
-                       prev = entry;
-                       continue;
-               }
-
                /*
                 * If there are as many broken entries as entries then we know
                 * not to trust this particular entry.
@@ -6863,6 +7383,16 @@ static struct extent_entry *find_most_right_entry(struct list_head *entries)
                        continue;
 
                /*
+                * Special case, when there are only two entries and 'best' is
+                * the first one
+                */
+               if (!prev) {
+                       best = entry;
+                       prev = entry;
+                       continue;
+               }
+
+               /*
                 * If our current entry == best then we can't be sure our best
                 * is really the best, so we need to keep searching.
                 */
@@ -7308,17 +7838,13 @@ static int delete_duplicate_records(struct btrfs_root *root,
 {
        struct btrfs_trans_handle *trans;
        LIST_HEAD(delete_list);
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct extent_record *tmp, *good, *n;
        int nr_del = 0;
        int ret = 0, err;
        struct btrfs_key key;
 
-       path = btrfs_alloc_path();
-       if (!path) {
-               ret = -ENOMEM;
-               goto out;
-       }
+       btrfs_init_path(&path);
 
        good = rec;
        /* Find the record that covers all of the duplicates. */
@@ -7370,16 +7896,16 @@ static int delete_duplicate_records(struct btrfs_root *root,
                        abort();
                }
 
-               ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+               ret = btrfs_search_slot(trans, root, &key, &path, -1, 1);
                if (ret) {
                        if (ret > 0)
                                ret = -EINVAL;
                        break;
                }
-               ret = btrfs_del_item(trans, root, path);
+               ret = btrfs_del_item(trans, root, &path);
                if (ret)
                        break;
-               btrfs_release_path(path);
+               btrfs_release_path(&path);
                nr_del++;
        }
        err = btrfs_commit_transaction(trans, root);
@@ -7400,7 +7926,7 @@ out:
                free(tmp);
        }
 
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
 
        if (!ret && !nr_del)
                rec->num_duplicates = 0;
@@ -7513,15 +8039,13 @@ static int record_orphan_data_extents(struct btrfs_fs_info *fs_info,
        struct extent_backref *back;
        struct data_backref *dback;
        struct orphan_data_extent *orphan;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        int recorded_data_ref = 0;
        int ret = 0;
 
        if (rec->metadata)
                return 1;
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
+       btrfs_init_path(&path);
        list_for_each_entry(back, &rec->backrefs, list) {
                if (back->full_backref || !back->is_data ||
                    !back->found_extent_tree)
@@ -7543,7 +8067,8 @@ static int record_orphan_data_extents(struct btrfs_fs_info *fs_info,
                key.type = BTRFS_EXTENT_DATA_KEY;
                key.offset = dback->offset;
 
-               ret = btrfs_search_slot(NULL, dest_root, &key, path, 0, 0);
+               ret = btrfs_search_slot(NULL, dest_root, &key, &path, 0, 0);
+               btrfs_release_path(&path);
                /*
                 * For ret < 0, it's OK since the fs-tree may be corrupted,
                 * we need to record it for inode/file extent rebuild.
@@ -7570,7 +8095,7 @@ static int record_orphan_data_extents(struct btrfs_fs_info *fs_info,
                recorded_data_ref = 1;
        }
 out:
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        if (!ret)
                return !recorded_data_ref;
        else
@@ -7588,7 +8113,7 @@ static int fixup_extent_refs(struct btrfs_fs_info *info,
 {
        struct btrfs_trans_handle *trans = NULL;
        int ret;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct list_head *cur = rec->backrefs.next;
        struct cache_extent *cache;
        struct extent_backref *back;
@@ -7598,10 +8123,7 @@ static int fixup_extent_refs(struct btrfs_fs_info *info,
        if (rec->flag_block_full_backref)
                flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
+       btrfs_init_path(&path);
        if (rec->refs != rec->extent_item_refs && !rec->metadata) {
                /*
                 * Sometimes the backrefs themselves are so broken they don't
@@ -7610,13 +8132,13 @@ static int fixup_extent_refs(struct btrfs_fs_info *info,
                 * them into the list if we find the backref so that
                 * verify_backrefs can figure out what to do.
                 */
-               ret = find_possible_backrefs(info, path, extent_cache, rec);
+               ret = find_possible_backrefs(info, &path, extent_cache, rec);
                if (ret < 0)
                        goto out;
        }
 
        /* step one, make sure all of the backrefs agree */
-       ret = verify_backrefs(info, path, rec);
+       ret = verify_backrefs(info, &path, rec);
        if (ret < 0)
                goto out;
 
@@ -7627,7 +8149,7 @@ static int fixup_extent_refs(struct btrfs_fs_info *info,
        }
 
        /* step two, delete all the existing records */
-       ret = delete_extent_records(trans, info->extent_root, path,
+       ret = delete_extent_records(trans, info->extent_root, &path,
                                    rec->start, rec->max_size);
 
        if (ret < 0)
@@ -7654,7 +8176,7 @@ static int fixup_extent_refs(struct btrfs_fs_info *info,
                        continue;
 
                rec->bad_full_backref = 0;
-               ret = record_extent(trans, info, path, rec, back, allocated, flags);
+               ret = record_extent(trans, info, &path, rec, back, allocated, flags);
                allocated = 1;
 
                if (ret)
@@ -7667,7 +8189,7 @@ out:
                        ret = err;
        }
 
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return ret;
 }
 
@@ -7676,7 +8198,7 @@ static int fixup_extent_flags(struct btrfs_fs_info *fs_info,
 {
        struct btrfs_trans_handle *trans;
        struct btrfs_root *root = fs_info->extent_root;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct btrfs_extent_item *ei;
        struct btrfs_key key;
        u64 flags;
@@ -7691,32 +8213,27 @@ static int fixup_extent_flags(struct btrfs_fs_info *fs_info,
                key.offset = rec->max_size;
        }
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
        trans = btrfs_start_transaction(root, 0);
-       if (IS_ERR(trans)) {
-               btrfs_free_path(path);
+       if (IS_ERR(trans))
                return PTR_ERR(trans);
-       }
 
-       ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+       btrfs_init_path(&path);
+       ret = btrfs_search_slot(trans, root, &key, &path, 0, 1);
        if (ret < 0) {
-               btrfs_free_path(path);
+               btrfs_release_path(&path);
                btrfs_commit_transaction(trans, root);
                return ret;
        } else if (ret) {
                fprintf(stderr, "Didn't find extent for %llu\n",
                        (unsigned long long)rec->start);
-               btrfs_free_path(path);
+               btrfs_release_path(&path);
                btrfs_commit_transaction(trans, root);
                return -ENOENT;
        }
 
-       ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
+       ei = btrfs_item_ptr(path.nodes[0], path.slots[0],
                            struct btrfs_extent_item);
-       flags = btrfs_extent_flags(path->nodes[0], ei);
+       flags = btrfs_extent_flags(path.nodes[0], ei);
        if (rec->flag_block_full_backref) {
                fprintf(stderr, "setting full backref on %llu\n",
                        (unsigned long long)key.objectid);
@@ -7726,9 +8243,9 @@ static int fixup_extent_flags(struct btrfs_fs_info *fs_info,
                        (unsigned long long)key.objectid);
                flags &= ~BTRFS_BLOCK_FLAG_FULL_BACKREF;
        }
-       btrfs_set_extent_flags(path->nodes[0], ei, flags);
-       btrfs_mark_buffer_dirty(path->nodes[0]);
-       btrfs_free_path(path);
+       btrfs_set_extent_flags(path.nodes[0], ei, flags);
+       btrfs_mark_buffer_dirty(path.nodes[0]);
+       btrfs_release_path(&path);
        return btrfs_commit_transaction(trans, root);
 }
 
@@ -10267,24 +10784,20 @@ static int pin_metadata_blocks(struct btrfs_fs_info *fs_info)
 static int reset_block_groups(struct btrfs_fs_info *fs_info)
 {
        struct btrfs_block_group_cache *cache;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct extent_buffer *leaf;
        struct btrfs_chunk *chunk;
        struct btrfs_key key;
        int ret;
        u64 start;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
+       btrfs_init_path(&path);
        key.objectid = 0;
        key.type = BTRFS_CHUNK_ITEM_KEY;
        key.offset = 0;
-
-       ret = btrfs_search_slot(NULL, fs_info->chunk_root, &key, path, 0, 0);
+       ret = btrfs_search_slot(NULL, fs_info->chunk_root, &key, &path, 0, 0);
        if (ret < 0) {
-               btrfs_free_path(path);
+               btrfs_release_path(&path);
                return ret;
        }
 
@@ -10299,10 +10812,10 @@ static int reset_block_groups(struct btrfs_fs_info *fs_info)
 
        /* First we need to create the in-memory block groups */
        while (1) {
-               if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
-                       ret = btrfs_next_leaf(fs_info->chunk_root, path);
+               if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
+                       ret = btrfs_next_leaf(fs_info->chunk_root, &path);
                        if (ret < 0) {
-                               btrfs_free_path(path);
+                               btrfs_release_path(&path);
                                return ret;
                        }
                        if (ret) {
@@ -10310,15 +10823,14 @@ static int reset_block_groups(struct btrfs_fs_info *fs_info)
                                break;
                        }
                }
-               leaf = path->nodes[0];
-               btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+               leaf = path.nodes[0];
+               btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
                if (key.type != BTRFS_CHUNK_ITEM_KEY) {
-                       path->slots[0]++;
+                       path.slots[0]++;
                        continue;
                }
 
-               chunk = btrfs_item_ptr(leaf, path->slots[0],
-                                      struct btrfs_chunk);
+               chunk = btrfs_item_ptr(leaf, path.slots[0], struct btrfs_chunk);
                btrfs_add_block_group(fs_info, 0,
                                      btrfs_chunk_type(leaf, chunk),
                                      key.objectid, key.offset,
@@ -10326,7 +10838,7 @@ static int reset_block_groups(struct btrfs_fs_info *fs_info)
                set_extent_dirty(&fs_info->free_space_cache, key.offset,
                                 key.offset + btrfs_chunk_length(leaf, chunk),
                                 GFP_NOFS);
-               path->slots[0]++;
+               path.slots[0]++;
        }
        start = 0;
        while (1) {
@@ -10337,7 +10849,7 @@ static int reset_block_groups(struct btrfs_fs_info *fs_info)
                start = cache->key.objectid + cache->key.offset;
        }
 
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return 0;
 }
 
@@ -10345,22 +10857,18 @@ static int reset_balance(struct btrfs_trans_handle *trans,
                         struct btrfs_fs_info *fs_info)
 {
        struct btrfs_root *root = fs_info->tree_root;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct extent_buffer *leaf;
        struct btrfs_key key;
        int del_slot, del_nr = 0;
        int ret;
        int found = 0;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
+       btrfs_init_path(&path);
        key.objectid = BTRFS_BALANCE_OBJECTID;
        key.type = BTRFS_BALANCE_ITEM_KEY;
        key.offset = 0;
-
-       ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+       ret = btrfs_search_slot(trans, root, &key, &path, -1, 1);
        if (ret) {
                if (ret > 0)
                        ret = 0;
@@ -10370,64 +10878,63 @@ static int reset_balance(struct btrfs_trans_handle *trans,
                        goto out;
        }
 
-       ret = btrfs_del_item(trans, root, path);
+       ret = btrfs_del_item(trans, root, &path);
        if (ret)
                goto out;
-       btrfs_release_path(path);
+       btrfs_release_path(&path);
 
        key.objectid = BTRFS_TREE_RELOC_OBJECTID;
        key.type = BTRFS_ROOT_ITEM_KEY;
        key.offset = 0;
-
-       ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+       ret = btrfs_search_slot(trans, root, &key, &path, -1, 1);
        if (ret < 0)
                goto out;
        while (1) {
-               if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
+               if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
                        if (!found)
                                break;
 
                        if (del_nr) {
-                               ret = btrfs_del_items(trans, root, path,
+                               ret = btrfs_del_items(trans, root, &path,
                                                      del_slot, del_nr);
                                del_nr = 0;
                                if (ret)
                                        goto out;
                        }
                        key.offset++;
-                       btrfs_release_path(path);
+                       btrfs_release_path(&path);
 
                        found = 0;
-                       ret = btrfs_search_slot(trans, root, &key, path,
+                       ret = btrfs_search_slot(trans, root, &key, &path,
                                                -1, 1);
                        if (ret < 0)
                                goto out;
                        continue;
                }
                found = 1;
-               leaf = path->nodes[0];
-               btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+               leaf = path.nodes[0];
+               btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
                if (key.objectid > BTRFS_TREE_RELOC_OBJECTID)
                        break;
                if (key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
-                       path->slots[0]++;
+                       path.slots[0]++;
                        continue;
                }
                if (!del_nr) {
-                       del_slot = path->slots[0];
+                       del_slot = path.slots[0];
                        del_nr = 1;
                } else {
                        del_nr++;
                }
-               path->slots[0]++;
+               path.slots[0]++;
        }
 
        if (del_nr) {
-               ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
+               ret = btrfs_del_items(trans, root, &path, del_slot, del_nr);
                if (ret)
                        goto out;
        }
-       btrfs_release_path(path);
+       btrfs_release_path(&path);
 
 reinit_data_reloc:
        key.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
@@ -10445,7 +10952,7 @@ reinit_data_reloc:
                goto out;
        ret = btrfs_make_root_dir(trans, root, BTRFS_FIRST_FREE_OBJECTID);
 out:
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return ret;
 }
 
@@ -10535,7 +11042,7 @@ static int reinit_extent_tree(struct btrfs_trans_handle *trans,
 
 static int recow_extent_buffer(struct btrfs_root *root, struct extent_buffer *eb)
 {
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct btrfs_trans_handle *trans;
        struct btrfs_key key;
        int ret;
@@ -10552,31 +11059,26 @@ static int recow_extent_buffer(struct btrfs_root *root, struct extent_buffer *eb
                return PTR_ERR(root);
        }
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
        trans = btrfs_start_transaction(root, 1);
-       if (IS_ERR(trans)) {
-               btrfs_free_path(path);
+       if (IS_ERR(trans))
                return PTR_ERR(trans);
-       }
 
-       path->lowest_level = btrfs_header_level(eb);
-       if (path->lowest_level)
+       btrfs_init_path(&path);
+       path.lowest_level = btrfs_header_level(eb);
+       if (path.lowest_level)
                btrfs_node_key_to_cpu(eb, &key, 0);
        else
                btrfs_item_key_to_cpu(eb, &key, 0);
 
-       ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+       ret = btrfs_search_slot(trans, root, &key, &path, 0, 1);
        btrfs_commit_transaction(trans, root);
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return ret;
 }
 
 static int delete_bad_item(struct btrfs_root *root, struct bad_item *bad)
 {
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct btrfs_trans_handle *trans;
        struct btrfs_key key;
        int ret;
@@ -10594,26 +11096,21 @@ static int delete_bad_item(struct btrfs_root *root, struct bad_item *bad)
                return PTR_ERR(root);
        }
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
        trans = btrfs_start_transaction(root, 1);
-       if (IS_ERR(trans)) {
-               btrfs_free_path(path);
+       if (IS_ERR(trans))
                return PTR_ERR(trans);
-       }
 
-       ret = btrfs_search_slot(trans, root, &bad->key, path, -1, 1);
+       btrfs_init_path(&path);
+       ret = btrfs_search_slot(trans, root, &bad->key, &path, -1, 1);
        if (ret) {
                if (ret > 0)
                        ret = 0;
                goto out;
        }
-       ret = btrfs_del_item(trans, root, path);
+       ret = btrfs_del_item(trans, root, &path);
 out:
        btrfs_commit_transaction(trans, root);
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return ret;
 }
 
@@ -10660,7 +11157,7 @@ static int fill_csum_tree_from_one_fs_root(struct btrfs_trans_handle *trans,
                                      struct btrfs_root *csum_root,
                                      struct btrfs_root *cur_root)
 {
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct btrfs_key key;
        struct extent_buffer *node;
        struct btrfs_file_extent_item *fi;
@@ -10670,30 +11167,25 @@ static int fill_csum_tree_from_one_fs_root(struct btrfs_trans_handle *trans,
        int slot = 0;
        int ret = 0;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
        buf = malloc(cur_root->fs_info->csum_root->sectorsize);
-       if (!buf) {
-               ret = -ENOMEM;
-               goto out;
-       }
+       if (!buf)
+               return -ENOMEM;
 
+       btrfs_init_path(&path);
        key.objectid = 0;
        key.offset = 0;
        key.type = 0;
-
-       ret = btrfs_search_slot(NULL, cur_root, &key, path, 0, 0);
+       ret = btrfs_search_slot(NULL, cur_root, &key, &path, 0, 0);
        if (ret < 0)
                goto out;
        /* Iterate all regular file extents and fill its csum */
        while (1) {
-               btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+               btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
 
                if (key.type != BTRFS_EXTENT_DATA_KEY)
                        goto next;
-               node = path->nodes[0];
-               slot = path->slots[0];
+               node = path.nodes[0];
+               slot = path.slots[0];
                fi = btrfs_item_ptr(node, slot, struct btrfs_file_extent_item);
                if (btrfs_file_extent_type(node, fi) != BTRFS_FILE_EXTENT_REG)
                        goto next;
@@ -10710,7 +11202,7 @@ next:
                 * TODO: if next leaf is corrupted, jump to nearest next valid
                 * leaf.
                 */
-               ret = btrfs_next_item(cur_root, path);
+               ret = btrfs_next_item(cur_root, &path);
                if (ret < 0)
                        goto out;
                if (ret > 0) {
@@ -10720,7 +11212,7 @@ next:
        }
 
 out:
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        free(buf);
        return ret;
 }
@@ -10729,7 +11221,7 @@ static int fill_csum_tree_from_fs(struct btrfs_trans_handle *trans,
                                  struct btrfs_root *csum_root)
 {
        struct btrfs_fs_info *fs_info = csum_root->fs_info;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct btrfs_root *tree_root = fs_info->tree_root;
        struct btrfs_root *cur_root;
        struct extent_buffer *node;
@@ -10737,15 +11229,11 @@ static int fill_csum_tree_from_fs(struct btrfs_trans_handle *trans,
        int slot = 0;
        int ret = 0;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
+       btrfs_init_path(&path);
        key.objectid = BTRFS_FS_TREE_OBJECTID;
        key.offset = 0;
        key.type = BTRFS_ROOT_ITEM_KEY;
-
-       ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
+       ret = btrfs_search_slot(NULL, tree_root, &key, &path, 0, 0);
        if (ret < 0)
                goto out;
        if (ret > 0) {
@@ -10754,8 +11242,8 @@ static int fill_csum_tree_from_fs(struct btrfs_trans_handle *trans,
        }
 
        while (1) {
-               node = path->nodes[0];
-               slot = path->slots[0];
+               node = path.nodes[0];
+               slot = path.slots[0];
                btrfs_item_key_to_cpu(node, &key, slot);
                if (key.objectid > BTRFS_LAST_FREE_OBJECTID)
                        goto out;
@@ -10776,7 +11264,7 @@ static int fill_csum_tree_from_fs(struct btrfs_trans_handle *trans,
                if (ret < 0)
                        goto out;
 next:
-               ret = btrfs_next_item(tree_root, path);
+               ret = btrfs_next_item(tree_root, &path);
                if (ret > 0) {
                        ret = 0;
                        goto out;
@@ -10786,7 +11274,7 @@ next:
        }
 
 out:
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        return ret;
 }
 
@@ -10794,36 +11282,32 @@ static int fill_csum_tree_from_extent(struct btrfs_trans_handle *trans,
                                      struct btrfs_root *csum_root)
 {
        struct btrfs_root *extent_root = csum_root->fs_info->extent_root;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct btrfs_extent_item *ei;
        struct extent_buffer *leaf;
        char *buf;
        struct btrfs_key key;
        int ret;
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
+       btrfs_init_path(&path);
        key.objectid = 0;
        key.type = BTRFS_EXTENT_ITEM_KEY;
        key.offset = 0;
-
-       ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
+       ret = btrfs_search_slot(NULL, extent_root, &key, &path, 0, 0);
        if (ret < 0) {
-               btrfs_free_path(path);
+               btrfs_release_path(&path);
                return ret;
        }
 
        buf = malloc(csum_root->sectorsize);
        if (!buf) {
-               btrfs_free_path(path);
+               btrfs_release_path(&path);
                return -ENOMEM;
        }
 
        while (1) {
-               if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
-                       ret = btrfs_next_leaf(extent_root, path);
+               if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
+                       ret = btrfs_next_leaf(extent_root, &path);
                        if (ret < 0)
                                break;
                        if (ret) {
@@ -10831,19 +11315,19 @@ static int fill_csum_tree_from_extent(struct btrfs_trans_handle *trans,
                                break;
                        }
                }
-               leaf = path->nodes[0];
+               leaf = path.nodes[0];
 
-               btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+               btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
                if (key.type != BTRFS_EXTENT_ITEM_KEY) {
-                       path->slots[0]++;
+                       path.slots[0]++;
                        continue;
                }
 
-               ei = btrfs_item_ptr(leaf, path->slots[0],
+               ei = btrfs_item_ptr(leaf, path.slots[0],
                                    struct btrfs_extent_item);
                if (!(btrfs_extent_flags(leaf, ei) &
                      BTRFS_EXTENT_FLAG_DATA)) {
-                       path->slots[0]++;
+                       path.slots[0]++;
                        continue;
                }
 
@@ -10851,10 +11335,10 @@ static int fill_csum_tree_from_extent(struct btrfs_trans_handle *trans,
                                    key.offset);
                if (ret)
                        break;
-               path->slots[0]++;
+               path.slots[0]++;
        }
 
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        free(buf);
        return ret;
 }
@@ -10902,7 +11386,7 @@ static int build_roots_info_cache(struct btrfs_fs_info *info)
        int ret = 0;
        struct btrfs_key key;
        struct extent_buffer *leaf;
-       struct btrfs_path *path;
+       struct btrfs_path path;
 
        if (!roots_info_cache) {
                roots_info_cache = malloc(sizeof(*roots_info_cache));
@@ -10911,24 +11395,20 @@ static int build_roots_info_cache(struct btrfs_fs_info *info)
                cache_tree_init(roots_info_cache);
        }
 
-       path = btrfs_alloc_path();
-       if (!path)
-               return -ENOMEM;
-
+       btrfs_init_path(&path);
        key.objectid = 0;
        key.type = BTRFS_EXTENT_ITEM_KEY;
        key.offset = 0;
-
-       ret = btrfs_search_slot(NULL, info->extent_root, &key, path, 0, 0);
+       ret = btrfs_search_slot(NULL, info->extent_root, &key, &path, 0, 0);
        if (ret < 0)
                goto out;
-       leaf = path->nodes[0];
+       leaf = path.nodes[0];
 
        while (1) {
                struct btrfs_key found_key;
                struct btrfs_extent_item *ei;
                struct btrfs_extent_inline_ref *iref;
-               int slot = path->slots[0];
+               int slot = path.slots[0];
                int type;
                u64 flags;
                u64 root_id;
@@ -10937,18 +11417,18 @@ static int build_roots_info_cache(struct btrfs_fs_info *info)
                struct root_item_info *rii;
 
                if (slot >= btrfs_header_nritems(leaf)) {
-                       ret = btrfs_next_leaf(info->extent_root, path);
+                       ret = btrfs_next_leaf(info->extent_root, &path);
                        if (ret < 0) {
                                break;
                        } else if (ret) {
                                ret = 0;
                                break;
                        }
-                       leaf = path->nodes[0];
-                       slot = path->slots[0];
+                       leaf = path.nodes[0];
+                       slot = path.slots[0];
                }
 
-               btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+               btrfs_item_key_to_cpu(leaf, &found_key, path.slots[0]);
 
                if (found_key.type != BTRFS_EXTENT_ITEM_KEY &&
                    found_key.type != BTRFS_METADATA_ITEM_KEY)
@@ -11011,11 +11491,11 @@ static int build_roots_info_cache(struct btrfs_fs_info *info)
                        rii->node_count++;
                }
 next:
-               path->slots[0]++;
+               path.slots[0]++;
        }
 
 out:
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
 
        return ret;
 }
@@ -11111,7 +11591,7 @@ static int maybe_repair_root_item(struct btrfs_fs_info *info,
  */
 static int repair_root_items(struct btrfs_fs_info *info)
 {
-       struct btrfs_path *path = NULL;
+       struct btrfs_path path;
        struct btrfs_key key;
        struct extent_buffer *leaf;
        struct btrfs_trans_handle *trans = NULL;
@@ -11119,16 +11599,12 @@ static int repair_root_items(struct btrfs_fs_info *info)
        int bad_roots = 0;
        int need_trans = 0;
 
+       btrfs_init_path(&path);
+
        ret = build_roots_info_cache(info);
        if (ret)
                goto out;
 
-       path = btrfs_alloc_path();
-       if (!path) {
-               ret = -ENOMEM;
-               goto out;
-       }
-
        key.objectid = BTRFS_FIRST_FREE_OBJECTID;
        key.type = BTRFS_ROOT_ITEM_KEY;
        key.offset = 0;
@@ -11147,19 +11623,19 @@ again:
                }
        }
 
-       ret = btrfs_search_slot(trans, info->tree_root, &key, path,
+       ret = btrfs_search_slot(trans, info->tree_root, &key, &path,
                                0, trans ? 1 : 0);
        if (ret < 0)
                goto out;
-       leaf = path->nodes[0];
+       leaf = path.nodes[0];
 
        while (1) {
                struct btrfs_key found_key;
 
-               if (path->slots[0] >= btrfs_header_nritems(leaf)) {
-                       int no_more_keys = find_next_key(path, &key);
+               if (path.slots[0] >= btrfs_header_nritems(leaf)) {
+                       int no_more_keys = find_next_key(&path, &key);
 
-                       btrfs_release_path(path);
+                       btrfs_release_path(&path);
                        if (trans) {
                                ret = btrfs_commit_transaction(trans,
                                                               info->tree_root);
@@ -11173,14 +11649,14 @@ again:
                        goto again;
                }
 
-               btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+               btrfs_item_key_to_cpu(leaf, &found_key, path.slots[0]);
 
                if (found_key.type != BTRFS_ROOT_ITEM_KEY)
                        goto next;
                if (found_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
                        goto next;
 
-               ret = maybe_repair_root_item(info, path, &found_key,
+               ret = maybe_repair_root_item(info, &path, &found_key,
                                             trans ? 0 : 1);
                if (ret < 0)
                        goto out;
@@ -11188,18 +11664,18 @@ again:
                        if (!trans && repair) {
                                need_trans = 1;
                                key = found_key;
-                               btrfs_release_path(path);
+                               btrfs_release_path(&path);
                                goto again;
                        }
                        bad_roots++;
                }
 next:
-               path->slots[0]++;
+               path.slots[0]++;
        }
        ret = 0;
 out:
        free_roots_info_cache();
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        if (trans)
                btrfs_commit_transaction(trans, info->tree_root);
        if (ret < 0)
@@ -11208,6 +11684,36 @@ out:
        return bad_roots;
 }
 
+static int clear_free_space_cache(struct btrfs_fs_info *fs_info)
+{
+       struct btrfs_trans_handle *trans;
+       struct btrfs_block_group_cache *bg_cache;
+       u64 current = 0;
+       int ret = 0;
+
+       /* Clear all free space cache inodes and its extent data */
+       while (1) {
+               bg_cache = btrfs_lookup_first_block_group(fs_info, current);
+               if (!bg_cache)
+                       break;
+               ret = btrfs_clear_free_space_cache(fs_info, bg_cache);
+               if (ret < 0)
+                       return ret;
+               current = bg_cache->key.objectid + bg_cache->key.offset;
+       }
+
+       /* Don't forget to set cache_generation to -1 */
+       trans = btrfs_start_transaction(fs_info->tree_root, 0);
+       if (IS_ERR(trans)) {
+               error("failed to update super block cache generation");
+               return PTR_ERR(trans);
+       }
+       btrfs_set_super_cache_generation(fs_info->super_copy, (u64)-1);
+       btrfs_commit_transaction(trans, fs_info->tree_root);
+
+       return ret;
+}
+
 const char * const cmd_check_usage[] = {
        "btrfs check [options] <device>",
        "Check structural integrity of a filesystem (unmounted).",
@@ -11235,6 +11741,7 @@ const char * const cmd_check_usage[] = {
        "-r|--tree-root <bytenr>     use the given bytenr for the tree root",
        "--chunk-root <bytenr>       use the given bytenr for the chunk tree root",
        "-p|--progress               indicate progress",
+       "--clear-space-cache v1|v2   clear space cache for v1 or v2",
        NULL
 };
 
@@ -11252,6 +11759,7 @@ int cmd_check(int argc, char **argv)
        u64 num;
        int init_csum_tree = 0;
        int readonly = 0;
+       int clear_space_cache = 0;
        int qgroup_report = 0;
        int qgroups_repaired = 0;
        unsigned ctree_flags = OPEN_CTREE_EXCLUSIVE;
@@ -11261,7 +11769,7 @@ int cmd_check(int argc, char **argv)
                enum { GETOPT_VAL_REPAIR = 257, GETOPT_VAL_INIT_CSUM,
                        GETOPT_VAL_INIT_EXTENT, GETOPT_VAL_CHECK_CSUM,
                        GETOPT_VAL_READONLY, GETOPT_VAL_CHUNK_TREE,
-                       GETOPT_VAL_MODE };
+                       GETOPT_VAL_MODE, GETOPT_VAL_CLEAR_SPACE_CACHE };
                static const struct option long_options[] = {
                        { "super", required_argument, NULL, 's' },
                        { "repair", no_argument, NULL, GETOPT_VAL_REPAIR },
@@ -11281,6 +11789,8 @@ int cmd_check(int argc, char **argv)
                        { "progress", no_argument, NULL, 'p' },
                        { "mode", required_argument, NULL,
                                GETOPT_VAL_MODE },
+                       { "clear-space-cache", required_argument, NULL,
+                               GETOPT_VAL_CLEAR_SPACE_CACHE},
                        { NULL, 0, NULL, 0}
                };
 
@@ -11352,6 +11862,19 @@ int cmd_check(int argc, char **argv)
                                        exit(1);
                                }
                                break;
+                       case GETOPT_VAL_CLEAR_SPACE_CACHE:
+                               if (strcmp(optarg, "v1") == 0) {
+                                       clear_space_cache = 1;
+                               } else if (strcmp(optarg, "v2") == 0) {
+                                       clear_space_cache = 2;
+                                       ctree_flags |= OPEN_CTREE_INVALIDATE_FST;
+                               } else {
+                                       error(
+               "invalid argument to --clear-space-cache, must be v1 or v2");
+                                       exit(1);
+                               }
+                               ctree_flags |= OPEN_CTREE_WRITES;
+                               break;
                }
        }
 
@@ -11403,6 +11926,40 @@ int cmd_check(int argc, char **argv)
 
        global_info = info;
        root = info->fs_root;
+       if (clear_space_cache == 1) {
+               if (btrfs_fs_compat_ro(info,
+                               BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE)) {
+                       error(
+               "free space cache v2 detected, use --clear-space-cache v2");
+                       ret = 1;
+                       goto close_out;
+               }
+               printf("Clearing free space cache\n");
+               ret = clear_free_space_cache(info);
+               if (ret) {
+                       error("failed to clear free space cache");
+                       ret = 1;
+               } else {
+                       printf("Free space cache cleared\n");
+               }
+               goto close_out;
+       } else if (clear_space_cache == 2) {
+               if (!btrfs_fs_compat_ro(info,
+                                       BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE)) {
+                       printf("no free space cache v2 to clear\n");
+                       ret = 0;
+                       goto close_out;
+               }
+               printf("Clear free space cache v2\n");
+               ret = btrfs_clear_free_space_tree(info);
+               if (ret) {
+                       error("failed to clear free space cache v2: %d", ret);
+                       ret = 1;
+               } else {
+                       printf("free space cache v2 cleared\n");
+               }
+               goto close_out;
+       }
 
        /*
         * repair mode will force us to commit transaction which
@@ -11500,13 +12057,14 @@ int cmd_check(int argc, char **argv)
        }
 
        if (!ctx.progress_enabled)
-               printf("checking extents");
+               fprintf(stderr, "checking extents\n");
        if (check_mode == CHECK_MODE_LOWMEM)
                ret = check_chunks_and_extents_v2(root);
        else
                ret = check_chunks_and_extents(root);
        if (ret)
-               printf("Errors found in extent allocation tree or chunk allocation");
+               error(
+               "errors found in extent allocation tree or chunk allocation");
 
        ret = repair_root_items(info);
        if (ret < 0)