btrfs-progs: check: introduce function to check shared block ref
[platform/upstream/btrfs-progs.git] / cmds-check.c
index db121b1..5fbe5eb 100644 (file)
 #include "repair.h"
 #include "disk-io.h"
 #include "print-tree.h"
+#include "task-utils.h"
 #include "transaction.h"
 #include "utils.h"
 #include "commands.h"
 #include "free-space-cache.h"
+#include "free-space-tree.h"
 #include "btrfsck.h"
 #include "qgroup-verify.h"
 #include "rbtree-utils.h"
 #include "backref.h"
 #include "ulist.h"
 
+enum task_position {
+       TASK_EXTENTS,
+       TASK_FREE_SPACE,
+       TASK_FS_ROOTS,
+       TASK_NOTHING, /* have to be the last element */
+};
+
+struct task_ctx {
+       int progress_enabled;
+       enum task_position tp;
+
+       struct task_info *info;
+};
+
 static u64 bytes_used = 0;
 static u64 total_csum_bytes = 0;
 static u64 total_btree_bytes = 0;
@@ -51,13 +67,15 @@ static u64 data_bytes_referenced = 0;
 static int found_old_backref = 0;
 static LIST_HEAD(duplicate_extents);
 static LIST_HEAD(delete_items);
-static int repair = 0;
 static int no_holes = 0;
 static int init_extent_tree = 0;
 static int check_data_csum = 0;
+static struct btrfs_fs_info *global_info;
+static struct task_ctx ctx = { 0 };
+static struct cache_tree *roots_info_cache = NULL;
 
 struct extent_backref {
-       struct list_head list;
+       struct rb_node node;
        unsigned int is_data:1;
        unsigned int found_extent_tree:1;
        unsigned int full_backref:1;
@@ -65,6 +83,11 @@ struct extent_backref {
        unsigned int broken:1;
 };
 
+static inline struct extent_backref* rb_node_to_extent_backref(struct rb_node *node)
+{
+       return rb_entry(node, struct extent_backref, node);
+}
+
 struct data_backref {
        struct extent_backref node;
        union {
@@ -80,6 +103,61 @@ struct data_backref {
        u32 found_ref;
 };
 
+static inline struct data_backref* to_data_backref(struct extent_backref *back)
+{
+       return container_of(back, struct data_backref, node);
+}
+
+static int compare_data_backref(struct rb_node *node1, struct rb_node *node2)
+{
+       struct extent_backref *ext1 = rb_node_to_extent_backref(node1);
+       struct extent_backref *ext2 = rb_node_to_extent_backref(node2);
+       struct data_backref *back1 = to_data_backref(ext1);
+       struct data_backref *back2 = to_data_backref(ext2);
+
+       WARN_ON(!ext1->is_data);
+       WARN_ON(!ext2->is_data);
+
+       /* parent and root are a union, so this covers both */
+       if (back1->parent > back2->parent)
+               return 1;
+       if (back1->parent < back2->parent)
+               return -1;
+
+       /* This is a full backref and the parents match. */
+       if (back1->node.full_backref)
+               return 0;
+
+       if (back1->owner > back2->owner)
+               return 1;
+       if (back1->owner < back2->owner)
+               return -1;
+
+       if (back1->offset > back2->offset)
+               return 1;
+       if (back1->offset < back2->offset)
+               return -1;
+
+       if (back1->bytes > back2->bytes)
+               return 1;
+       if (back1->bytes < back2->bytes)
+               return -1;
+
+       if (back1->found_ref && back2->found_ref) {
+               if (back1->disk_bytenr > back2->disk_bytenr)
+                       return 1;
+               if (back1->disk_bytenr < back2->disk_bytenr)
+                       return -1;
+
+               if (back1->found_ref > back2->found_ref)
+                       return 1;
+               if (back1->found_ref < back2->found_ref)
+                       return -1;
+       }
+
+       return 0;
+}
+
 /*
  * Much like data_backref, just removed the undetermined members
  * and change it to use list_head.
@@ -103,9 +181,59 @@ struct tree_backref {
        };
 };
 
+static inline struct tree_backref* to_tree_backref(struct extent_backref *back)
+{
+       return container_of(back, struct tree_backref, node);
+}
+
+static int compare_tree_backref(struct rb_node *node1, struct rb_node *node2)
+{
+       struct extent_backref *ext1 = rb_node_to_extent_backref(node1);
+       struct extent_backref *ext2 = rb_node_to_extent_backref(node2);
+       struct tree_backref *back1 = to_tree_backref(ext1);
+       struct tree_backref *back2 = to_tree_backref(ext2);
+
+       WARN_ON(ext1->is_data);
+       WARN_ON(ext2->is_data);
+
+       /* parent and root are a union, so this covers both */
+       if (back1->parent > back2->parent)
+               return 1;
+       if (back1->parent < back2->parent)
+               return -1;
+
+       return 0;
+}
+
+static int compare_extent_backref(struct rb_node *node1, struct rb_node *node2)
+{
+       struct extent_backref *ext1 = rb_node_to_extent_backref(node1);
+       struct extent_backref *ext2 = rb_node_to_extent_backref(node2);
+
+       if (ext1->is_data > ext2->is_data)
+               return 1;
+
+       if (ext1->is_data < ext2->is_data)
+               return -1;
+
+       if (ext1->full_backref > ext2->full_backref)
+               return 1;
+       if (ext1->full_backref < ext2->full_backref)
+               return -1;
+
+       if (ext1->is_data)
+               return compare_data_backref(node1, node2);
+       else
+               return compare_tree_backref(node1, node2);
+}
+
+/* Explicit initialization for extent_record::flag_block_full_backref */
+enum { FLAG_UNSET = 2 };
+
 struct extent_record {
        struct list_head backrefs;
        struct list_head dups;
+       struct rb_root backref_tree;
        struct list_head list;
        struct cache_extent cache;
        struct btrfs_disk_key parent_key;
@@ -119,15 +247,22 @@ struct extent_record {
        u64 info_objectid;
        u32 num_duplicates;
        u8 info_level;
-       int flag_block_full_backref;
+       unsigned int flag_block_full_backref:2;
        unsigned int found_rec:1;
        unsigned int content_checked:1;
        unsigned int owner_ref_checked:1;
        unsigned int is_root:1;
        unsigned int metadata:1;
        unsigned int bad_full_backref:1;
+       unsigned int crossing_stripes:1;
+       unsigned int wrong_chunk_type:1;
 };
 
+static inline struct extent_record* to_extent_record(struct list_head *entry)
+{
+       return container_of(entry, struct extent_record, list);
+}
+
 struct inode_backref {
        struct list_head list;
        unsigned int found_dir_item:1;
@@ -142,6 +277,11 @@ struct inode_backref {
        char name[0];
 };
 
+static inline struct inode_backref* to_inode_backref(struct list_head *entry)
+{
+       return list_entry(entry, struct inode_backref, list);
+}
+
 struct root_item_record {
        struct list_head list;
        u64 objectid;
@@ -173,6 +313,173 @@ struct file_extent_hole {
        u64 len;
 };
 
+struct inode_record {
+       struct list_head backrefs;
+       unsigned int checked:1;
+       unsigned int merging:1;
+       unsigned int found_inode_item:1;
+       unsigned int found_dir_item:1;
+       unsigned int found_file_extent:1;
+       unsigned int found_csum_item:1;
+       unsigned int some_csum_missing:1;
+       unsigned int nodatasum:1;
+       int errors;
+
+       u64 ino;
+       u32 nlink;
+       u32 imode;
+       u64 isize;
+       u64 nbytes;
+
+       u32 found_link;
+       u64 found_size;
+       u64 extent_start;
+       u64 extent_end;
+       struct rb_root holes;
+       struct list_head orphan_extents;
+
+       u32 refs;
+};
+
+#define I_ERR_NO_INODE_ITEM            (1 << 0)
+#define I_ERR_NO_ORPHAN_ITEM           (1 << 1)
+#define I_ERR_DUP_INODE_ITEM           (1 << 2)
+#define I_ERR_DUP_DIR_INDEX            (1 << 3)
+#define I_ERR_ODD_DIR_ITEM             (1 << 4)
+#define I_ERR_ODD_FILE_EXTENT          (1 << 5)
+#define I_ERR_BAD_FILE_EXTENT          (1 << 6)
+#define I_ERR_FILE_EXTENT_OVERLAP      (1 << 7)
+#define I_ERR_FILE_EXTENT_DISCOUNT     (1 << 8) // 100
+#define I_ERR_DIR_ISIZE_WRONG          (1 << 9)
+#define I_ERR_FILE_NBYTES_WRONG                (1 << 10) // 400
+#define I_ERR_ODD_CSUM_ITEM            (1 << 11)
+#define I_ERR_SOME_CSUM_MISSING                (1 << 12)
+#define I_ERR_LINK_COUNT_WRONG         (1 << 13)
+#define I_ERR_FILE_EXTENT_ORPHAN       (1 << 14)
+
+struct root_backref {
+       struct list_head list;
+       unsigned int found_dir_item:1;
+       unsigned int found_dir_index:1;
+       unsigned int found_back_ref:1;
+       unsigned int found_forward_ref:1;
+       unsigned int reachable:1;
+       int errors;
+       u64 ref_root;
+       u64 dir;
+       u64 index;
+       u16 namelen;
+       char name[0];
+};
+
+static inline struct root_backref* to_root_backref(struct list_head *entry)
+{
+       return list_entry(entry, struct root_backref, list);
+}
+
+struct root_record {
+       struct list_head backrefs;
+       struct cache_extent cache;
+       unsigned int found_root_item:1;
+       u64 objectid;
+       u32 found_ref;
+};
+
+struct ptr_node {
+       struct cache_extent cache;
+       void *data;
+};
+
+struct shared_node {
+       struct cache_extent cache;
+       struct cache_tree root_cache;
+       struct cache_tree inode_cache;
+       struct inode_record *current;
+       u32 refs;
+};
+
+struct block_info {
+       u64 start;
+       u32 size;
+};
+
+struct walk_control {
+       struct cache_tree shared;
+       struct shared_node *nodes[BTRFS_MAX_LEVEL];
+       int active_node;
+       int root_level;
+};
+
+struct bad_item {
+       struct btrfs_key key;
+       u64 root_id;
+       struct list_head list;
+};
+
+struct extent_entry {
+       u64 bytenr;
+       u64 bytes;
+       int count;
+       int broken;
+       struct list_head list;
+};
+
+struct root_item_info {
+       /* level of the root */
+       u8 level;
+       /* number of nodes at this level, must be 1 for a root */
+       int node_count;
+       u64 bytenr;
+       u64 gen;
+       struct cache_extent cache_extent;
+};
+
+/*
+ * Error bit for low memory mode check.
+ *
+ * Currently no caller cares about it yet.  Just internal use for error
+ * classification.
+ */
+#define BACKREF_MISSING                (1 << 0) /* Backref missing in extent tree */
+#define BACKREF_MISMATCH       (1 << 1) /* Backref exists but does not match */
+#define BYTES_UNALIGNED                (1 << 2) /* Some bytes are not aligned */
+#define REFERENCER_MISSING     (1 << 3) /* Referencer not found */
+#define REFERENCER_MISMATCH    (1 << 4) /* Referenceer found but does not match */
+
+static void *print_status_check(void *p)
+{
+       struct task_ctx *priv = p;
+       const char work_indicator[] = { '.', 'o', 'O', 'o' };
+       uint32_t count = 0;
+       static char *task_position_string[] = {
+               "checking extents",
+               "checking free space cache",
+               "checking fs roots",
+       };
+
+       task_period_start(priv->info, 1000 /* 1s */);
+
+       if (priv->tp == TASK_NOTHING)
+               return NULL;
+
+       while (1) {
+               printf("%s [%c]\r", task_position_string[priv->tp],
+                               work_indicator[count % 4]);
+               count++;
+               fflush(stdout);
+               task_period_wait(priv->info);
+       }
+       return NULL;
+}
+
+static int print_status_return(void *p)
+{
+       printf("\n");
+       fflush(stdout);
+
+       return 0;
+}
+
 /* Compatible function to allow reuse of old codes */
 static u64 first_extent_gap(struct rb_root *holes)
 {
@@ -185,7 +492,7 @@ static u64 first_extent_gap(struct rb_root *holes)
        return hole->start;
 }
 
-int compare_hole(struct rb_node *node1, struct rb_node *node2)
+static int compare_hole(struct rb_node *node1, struct rb_node *node2)
 {
        struct file_extent_hole *hole1;
        struct file_extent_hole *hole2;
@@ -305,7 +612,7 @@ static int del_file_extent_hole(struct rb_root *holes,
                return -EEXIST;
 
        /*
-        * Now there will be no overflap, delete the hole and re-add the
+        * Now there will be no overlap, delete the hole and re-add the
         * split(s) if they exists.
         */
        if (start > hole->start) {
@@ -365,133 +672,35 @@ static void free_file_extent_holes(struct rb_root *holes)
        }
 }
 
-struct inode_record {
-       struct list_head backrefs;
-       unsigned int checked:1;
-       unsigned int merging:1;
-       unsigned int found_inode_item:1;
-       unsigned int found_dir_item:1;
-       unsigned int found_file_extent:1;
-       unsigned int found_csum_item:1;
-       unsigned int some_csum_missing:1;
-       unsigned int nodatasum:1;
-       int errors;
+static void reset_cached_block_groups(struct btrfs_fs_info *fs_info);
 
-       u64 ino;
-       u32 nlink;
-       u32 imode;
-       u64 isize;
-       u64 nbytes;
+static void record_root_in_trans(struct btrfs_trans_handle *trans,
+                                struct btrfs_root *root)
+{
+       if (root->last_trans != trans->transid) {
+               root->track_dirty = 1;
+               root->last_trans = trans->transid;
+               root->commit_root = root->node;
+               extent_buffer_get(root->node);
+       }
+}
 
-       u32 found_link;
-       u64 found_size;
-       u64 extent_start;
-       u64 extent_end;
-       struct rb_root holes;
-       struct list_head orphan_extents;
+static u8 imode_to_type(u32 imode)
+{
+#define S_SHIFT 12
+       static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
+               [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
+               [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
+               [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
+               [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
+               [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
+               [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
+               [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
+       };
 
-       u32 refs;
-};
-
-#define I_ERR_NO_INODE_ITEM            (1 << 0)
-#define I_ERR_NO_ORPHAN_ITEM           (1 << 1)
-#define I_ERR_DUP_INODE_ITEM           (1 << 2)
-#define I_ERR_DUP_DIR_INDEX            (1 << 3)
-#define I_ERR_ODD_DIR_ITEM             (1 << 4)
-#define I_ERR_ODD_FILE_EXTENT          (1 << 5)
-#define I_ERR_BAD_FILE_EXTENT          (1 << 6)
-#define I_ERR_FILE_EXTENT_OVERLAP      (1 << 7)
-#define I_ERR_FILE_EXTENT_DISCOUNT     (1 << 8) // 100
-#define I_ERR_DIR_ISIZE_WRONG          (1 << 9)
-#define I_ERR_FILE_NBYTES_WRONG                (1 << 10) // 400
-#define I_ERR_ODD_CSUM_ITEM            (1 << 11)
-#define I_ERR_SOME_CSUM_MISSING                (1 << 12)
-#define I_ERR_LINK_COUNT_WRONG         (1 << 13)
-#define I_ERR_FILE_EXTENT_ORPHAN       (1 << 14)
-
-struct root_backref {
-       struct list_head list;
-       unsigned int found_dir_item:1;
-       unsigned int found_dir_index:1;
-       unsigned int found_back_ref:1;
-       unsigned int found_forward_ref:1;
-       unsigned int reachable:1;
-       int errors;
-       u64 ref_root;
-       u64 dir;
-       u64 index;
-       u16 namelen;
-       char name[0];
-};
-
-struct root_record {
-       struct list_head backrefs;
-       struct cache_extent cache;
-       unsigned int found_root_item:1;
-       u64 objectid;
-       u32 found_ref;
-};
-
-struct ptr_node {
-       struct cache_extent cache;
-       void *data;
-};
-
-struct shared_node {
-       struct cache_extent cache;
-       struct cache_tree root_cache;
-       struct cache_tree inode_cache;
-       struct inode_record *current;
-       u32 refs;
-};
-
-struct block_info {
-       u64 start;
-       u32 size;
-};
-
-struct walk_control {
-       struct cache_tree shared;
-       struct shared_node *nodes[BTRFS_MAX_LEVEL];
-       int active_node;
-       int root_level;
-};
-
-struct bad_item {
-       struct btrfs_key key;
-       u64 root_id;
-       struct list_head list;
-};
-
-static void reset_cached_block_groups(struct btrfs_fs_info *fs_info);
-
-static void record_root_in_trans(struct btrfs_trans_handle *trans,
-                                struct btrfs_root *root)
-{
-       if (root->last_trans != trans->transid) {
-               root->track_dirty = 1;
-               root->last_trans = trans->transid;
-               root->commit_root = root->node;
-               extent_buffer_get(root->node);
-       }
-}
-
-static u8 imode_to_type(u32 imode)
-{
-#define S_SHIFT 12
-       static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
-               [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
-               [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
-               [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
-               [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
-               [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
-               [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
-               [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
-       };
-
-       return btrfs_type_by_mode[(imode & S_IFMT) >> S_SHIFT];
-#undef S_SHIFT
-}
+       return btrfs_type_by_mode[(imode & S_IFMT) >> S_SHIFT];
+#undef S_SHIFT
+}
 
 static int device_record_compare(struct rb_node *node1, struct rb_node *node2)
 {
@@ -513,12 +722,15 @@ static struct inode_record *clone_inode_rec(struct inode_record *orig_rec)
        struct inode_record *rec;
        struct inode_backref *backref;
        struct inode_backref *orig;
+       struct inode_backref *tmp;
        struct orphan_data_extent *src_orphan;
        struct orphan_data_extent *dst_orphan;
        size_t size;
        int ret;
 
        rec = malloc(sizeof(*rec));
+       if (!rec)
+               return ERR_PTR(-ENOMEM);
        memcpy(rec, orig_rec, sizeof(*rec));
        rec->refs = 1;
        INIT_LIST_HEAD(&rec->backrefs);
@@ -528,13 +740,19 @@ static struct inode_record *clone_inode_rec(struct inode_record *orig_rec)
        list_for_each_entry(orig, &orig_rec->backrefs, list) {
                size = sizeof(*orig) + orig->namelen + 1;
                backref = malloc(size);
+               if (!backref) {
+                       ret = -ENOMEM;
+                       goto cleanup;
+               }
                memcpy(backref, orig, size);
                list_add_tail(&backref->list, &rec->backrefs);
        }
        list_for_each_entry(src_orphan, &orig_rec->orphan_extents, list) {
                dst_orphan = malloc(sizeof(*dst_orphan));
-               /* TODO: Fix all the HELL of un-catched -ENOMEM case */
-               BUG_ON(!dst_orphan);
+               if (!dst_orphan) {
+                       ret = -ENOMEM;
+                       goto cleanup;
+               }
                memcpy(dst_orphan, src_orphan, sizeof(*src_orphan));
                list_add_tail(&dst_orphan->list, &rec->orphan_extents);
        }
@@ -542,6 +760,23 @@ static struct inode_record *clone_inode_rec(struct inode_record *orig_rec)
        BUG_ON(ret < 0);
 
        return rec;
+
+cleanup:
+       if (!list_empty(&rec->backrefs))
+               list_for_each_entry_safe(orig, tmp, &rec->backrefs, list) {
+                       list_del(&orig->list);
+                       free(orig);
+               }
+
+       if (!list_empty(&rec->orphan_extents))
+               list_for_each_entry_safe(orig, tmp, &rec->orphan_extents, list) {
+                       list_del(&orig->list);
+                       free(orig);
+               }
+
+       free(rec);
+
+       return ERR_PTR(ret);
 }
 
 static void print_orphan_data_extents(struct list_head *orphan_extents,
@@ -615,15 +850,20 @@ static void print_inode_error(struct btrfs_root *root, struct inode_record *rec)
        if (errors & I_ERR_FILE_EXTENT_DISCOUNT) {
                struct file_extent_hole *hole;
                struct rb_node *node;
+               int found = 0;
 
                node = rb_first(&rec->holes);
                fprintf(stderr, "Found file extent holes:\n");
                while (node) {
+                       found = 1;
                        hole = rb_entry(node, struct file_extent_hole, node);
-                       fprintf(stderr, "\tstart: %llu, len:%llu\n",
+                       fprintf(stderr, "\tstart: %llu, len: %llu\n",
                                hole->start, hole->len);
                        node = rb_next(node);
                }
+               if (!found)
+                       fprintf(stderr, "\tstart: 0, len: %llu\n",
+                               round_up(rec->isize, root->sectorsize));
        }
 }
 
@@ -642,9 +882,9 @@ static void print_ref_error(int errors)
        if (errors & REF_ERR_DUP_INODE_REF)
                fprintf(stderr, ", dup inode ref");
        if (errors & REF_ERR_INDEX_UNMATCH)
-               fprintf(stderr, ", index unmatch");
+               fprintf(stderr, ", index mismatch");
        if (errors & REF_ERR_FILETYPE_UNMATCH)
-               fprintf(stderr, ", filetype unmatch");
+               fprintf(stderr, ", filetype mismatch");
        if (errors & REF_ERR_NAME_TOO_LONG)
                fprintf(stderr, ", name too long");
        if (errors & REF_ERR_NO_ROOT_REF)
@@ -672,11 +912,15 @@ static struct inode_record *get_inode_rec(struct cache_tree *inode_cache,
                rec = node->data;
                if (mod && rec->refs > 1) {
                        node->data = clone_inode_rec(rec);
+                       if (IS_ERR(node->data))
+                               return node->data;
                        rec->refs--;
                        rec = node->data;
                }
        } else if (mod) {
                rec = calloc(1, sizeof(*rec));
+               if (!rec)
+                       return ERR_PTR(-ENOMEM);
                rec->ino = ino;
                rec->extent_start = (u64)-1;
                rec->refs = 1;
@@ -685,6 +929,10 @@ static struct inode_record *get_inode_rec(struct cache_tree *inode_cache,
                rec->holes = RB_ROOT;
 
                node = malloc(sizeof(*node));
+               if (!node) {
+                       free(rec);
+                       return ERR_PTR(-ENOMEM);
+               }
                node->cache.start = ino;
                node->cache.size = 1;
                node->data = rec;
@@ -693,7 +941,8 @@ static struct inode_record *get_inode_rec(struct cache_tree *inode_cache,
                        rec->found_link = 1;
 
                ret = insert_cache_extent(inode_cache, &node->cache);
-               BUG_ON(ret);
+               if (ret)
+                       return ERR_PTR(-EEXIST);
        }
        return rec;
 }
@@ -718,8 +967,7 @@ static void free_inode_rec(struct inode_record *rec)
                return;
 
        while (!list_empty(&rec->backrefs)) {
-               backref = list_entry(rec->backrefs.next,
-                                    struct inode_backref, list);
+               backref = to_inode_backref(rec->backrefs.next);
                list_del(&backref->list);
                free(backref);
        }
@@ -752,7 +1000,8 @@ static void maybe_free_inode_rec(struct cache_tree *inode_cache,
                if (backref->found_dir_item && backref->found_dir_index) {
                        if (backref->filetype != filetype)
                                backref->errors |= REF_ERR_FILETYPE_UNMATCH;
-                       if (!backref->errors && backref->found_inode_ref) {
+                       if (!backref->errors && backref->found_inode_ref &&
+                           rec->nlink == rec->found_link) {
                                list_del(&backref->list);
                                free(backref);
                        }
@@ -858,6 +1107,8 @@ static struct inode_backref *get_inode_backref(struct inode_record *rec,
        }
 
        backref = malloc(sizeof(*backref) + namelen + 1);
+       if (!backref)
+               return NULL;
        memset(backref, 0, sizeof(*backref));
        backref->dir = dir;
        backref->namelen = namelen;
@@ -876,7 +1127,9 @@ static int add_inode_backref(struct cache_tree *inode_cache,
        struct inode_backref *backref;
 
        rec = get_inode_rec(inode_cache, ino, 1);
+       BUG_ON(IS_ERR(rec));
        backref = get_inode_backref(rec, name, namelen, dir);
+       BUG_ON(!backref);
        if (errors)
                backref->errors |= errors;
        if (itemtype == BTRFS_DIR_INDEX_KEY) {
@@ -1030,6 +1283,7 @@ again:
                        ins = node;
                } else {
                        ins = malloc(sizeof(*ins));
+                       BUG_ON(!ins);
                        ins->cache.start = node->cache.start;
                        ins->cache.size = node->cache.size;
                        ins->data = rec;
@@ -1038,6 +1292,7 @@ again:
                ret = insert_cache_extent(dst, &ins->cache);
                if (ret == -EEXIST) {
                        conflict = get_inode_rec(dst, rec->ino, 1);
+                       BUG_ON(IS_ERR(conflict));
                        merge_inode_recs(rec, conflict, dst);
                        if (rec->checked) {
                                conflict->checked = 1;
@@ -1065,6 +1320,7 @@ again:
                        maybe_free_inode_rec(dst, dst_node->current);
                }
                dst_node->current = get_inode_rec(dst, current_ino, 1);
+               BUG_ON(IS_ERR(dst_node->current));
        }
        return 0;
 }
@@ -1102,6 +1358,8 @@ static int add_shared_node(struct cache_tree *shared, u64 bytenr, u32 refs)
        struct shared_node *node;
 
        node = calloc(1, sizeof(*node));
+       if (!node)
+               return -ENOMEM;
        node->cache.start = bytenr;
        node->cache.size = 1;
        cache_tree_init(&node->root_cache);
@@ -1109,8 +1367,8 @@ static int add_shared_node(struct cache_tree *shared, u64 bytenr, u32 refs)
        node->refs = refs;
 
        ret = insert_cache_extent(shared, &node->cache);
-       BUG_ON(ret);
-       return 0;
+
+       return ret;
 }
 
 static int enter_shared_node(struct btrfs_root *root, u64 bytenr, u32 refs,
@@ -1118,6 +1376,7 @@ static int enter_shared_node(struct btrfs_root *root, u64 bytenr, u32 refs,
 {
        struct shared_node *node;
        struct shared_node *dest;
+       int ret;
 
        if (level == wc->active_node)
                return 0;
@@ -1125,7 +1384,8 @@ static int enter_shared_node(struct btrfs_root *root, u64 bytenr, u32 refs,
        BUG_ON(wc->active_node <= level);
        node = find_shared_node(&wc->shared, bytenr);
        if (!node) {
-               add_shared_node(&wc->shared, bytenr, refs);
+               ret = add_shared_node(&wc->shared, bytenr, refs);
+               BUG_ON(ret);
                node = find_shared_node(&wc->shared, bytenr);
                wc->nodes[level] = node;
                wc->active_node = level;
@@ -1605,6 +1865,7 @@ static int process_one_leaf(struct btrfs_root *root, struct extent_buffer *eb,
                        }
                        active_node->current = get_inode_rec(inode_cache,
                                                             key.objectid, 1);
+                       BUG_ON(IS_ERR(active_node->current));
                }
                switch (key.type) {
                case BTRFS_DIR_ITEM_KEY:
@@ -1646,7 +1907,7 @@ static void reada_walk_down(struct btrfs_root *root,
                return;
 
        nritems = btrfs_header_nritems(node);
-       blocksize = btrfs_level_size(root, level - 1);
+       blocksize = root->nodesize;
        for (i = slot; i < nritems; i++) {
                bytenr = btrfs_node_blockptr(node, i);
                ptr_gen = btrfs_node_ptr_generation(node, i);
@@ -1704,8 +1965,14 @@ static int check_child_node(struct btrfs_root *root,
        return ret;
 }
 
+struct node_refs {
+       u64 bytenr[BTRFS_MAX_LEVEL];
+       u64 refs[BTRFS_MAX_LEVEL];
+};
+
 static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
-                         struct walk_control *wc, int *level)
+                         struct walk_control *wc, int *level,
+                         struct node_refs *nrefs)
 {
        enum btrfs_tree_block_status status;
        u64 bytenr;
@@ -1718,12 +1985,20 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
 
        WARN_ON(*level < 0);
        WARN_ON(*level >= BTRFS_MAX_LEVEL);
-       ret = btrfs_lookup_extent_info(NULL, root,
+
+       if (path->nodes[*level]->start == nrefs->bytenr[*level]) {
+               refs = nrefs->refs[*level];
+               ret = 0;
+       } else {
+               ret = btrfs_lookup_extent_info(NULL, root,
                                       path->nodes[*level]->start,
                                       *level, 1, &refs, NULL);
-       if (ret < 0) {
-               err = ret;
-               goto out;
+               if (ret < 0) {
+                       err = ret;
+                       goto out;
+               }
+               nrefs->bytenr[*level] = path->nodes[*level]->start;
+               nrefs->refs[*level] = refs;
        }
 
        if (refs > 1) {
@@ -1753,11 +2028,20 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
                }
                bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
                ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
-               blocksize = btrfs_level_size(root, *level - 1);
-               ret = btrfs_lookup_extent_info(NULL, root, bytenr, *level - 1,
-                                              1, &refs, NULL);
-               if (ret < 0)
-                       refs = 0;
+               blocksize = root->nodesize;
+
+               if (bytenr == nrefs->bytenr[*level - 1]) {
+                       refs = nrefs->refs[*level - 1];
+               } else {
+                       ret = btrfs_lookup_extent_info(NULL, root, bytenr,
+                                       *level - 1, 1, &refs, NULL);
+                       if (ret < 0) {
+                               refs = 0;
+                       } else {
+                               nrefs->bytenr[*level - 1] = bytenr;
+                               nrefs->refs[*level - 1] = refs;
+                       }
+               }
 
                if (refs > 1) {
                        ret = enter_shared_node(root, bytenr, refs,
@@ -1783,7 +2067,7 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
                                btrfs_add_corrupt_extent_record(root->fs_info,
                                                &node_key,
                                                path->nodes[*level]->start,
-                                               root->leafsize, *level);
+                                               root->nodesize, *level);
                                err = -EIO;
                                goto out;
                        }
@@ -1850,7 +2134,7 @@ static int check_root_dir(struct inode_record *rec)
                goto out;
        if (list_empty(&rec->backrefs))
                goto out;
-       backref = list_entry(rec->backrefs.next, struct inode_backref, list);
+       backref = to_inode_backref(rec->backrefs.next);
        if (!backref->found_inode_ref)
                goto out;
        if (backref->index != 0 || backref->namelen != 2 ||
@@ -1918,6 +2202,39 @@ static int repair_inode_orphan_item(struct btrfs_trans_handle *trans,
        return ret;
 }
 
+static int repair_inode_nbytes(struct btrfs_trans_handle *trans,
+                              struct btrfs_root *root,
+                              struct btrfs_path *path,
+                              struct inode_record *rec)
+{
+       struct btrfs_inode_item *ei;
+       struct btrfs_key key;
+       int ret = 0;
+
+       key.objectid = rec->ino;
+       key.type = BTRFS_INODE_ITEM_KEY;
+       key.offset = 0;
+
+       ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+       if (ret) {
+               if (ret > 0)
+                       ret = -ENOENT;
+               goto out;
+       }
+
+       /* Since ret == 0, no need to check anything */
+       ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
+                           struct btrfs_inode_item);
+       btrfs_set_inode_nbytes(path->nodes[0], ei, rec->found_size);
+       btrfs_mark_buffer_dirty(path->nodes[0]);
+       rec->errors &= ~I_ERR_FILE_NBYTES_WRONG;
+       printf("reset nbytes for ino %llu root %llu\n",
+              rec->ino, root->root_key.objectid);
+out:
+       btrfs_release_path(path);
+       return ret;
+}
+
 static int add_missing_dir_index(struct btrfs_root *root,
                                 struct cache_tree *inode_cache,
                                 struct inode_record *rec,
@@ -1972,6 +2289,7 @@ static int add_missing_dir_index(struct btrfs_root *root,
 
        backref->found_dir_index = 1;
        dir_rec = get_inode_rec(inode_cache, backref->dir, 0);
+       BUG_ON(IS_ERR(dir_rec));
        if (!dir_rec)
                return 0;
        dir_rec->found_size += backref->namelen;
@@ -2301,7 +2619,7 @@ static int reset_nlink(struct btrfs_trans_handle *trans,
        list_for_each_entry(backref, &rec->backrefs, list) {
                ret = btrfs_add_link(trans, root, rec->ino, backref->dir,
                                     backref->name, backref->namelen,
-                                    backref->ref_type, &backref->index, 1);
+                                    backref->filetype, &backref->index, 1);
                if (ret < 0)
                        goto out;
        }
@@ -2365,7 +2683,7 @@ static int repair_inode_nlinks(struct btrfs_trans_handle *trans,
                                  BTRFS_FIRST_FREE_OBJECTID, &lost_found_ino,
                                  mode);
                if (ret < 0) {
-                       fprintf(stderr, "Failed to create '%s' dir: %s",
+                       fprintf(stderr, "Failed to create '%s' dir: %s\n",
                                dir_name, strerror(-ret));
                        goto out;
                }
@@ -2393,7 +2711,7 @@ static int repair_inode_nlinks(struct btrfs_trans_handle *trans,
                }
                if (ret < 0) {
                        fprintf(stderr,
-                               "Failed to link the inode %llu to %s dir: %s",
+                               "Failed to link the inode %llu to %s dir: %s\n",
                                rec->ino, dir_name, strerror(-ret));
                        goto out;
                }
@@ -2529,7 +2847,7 @@ static int repair_inode_no_item(struct btrfs_trans_handle *trans,
                        type_recovered = 1;
                        filetype = BTRFS_FT_REG_FILE;
                } else{
-                       printf("Can't determint the filetype for inode %llu, assume it is a normal file\n",
+                       printf("Can't determine the filetype for inode %llu, assume it is a normal file\n",
                               rec->ino);
                        type_recovered = 1;
                        filetype = BTRFS_FT_REG_FILE;
@@ -2626,11 +2944,13 @@ static int repair_inode_discount_extent(struct btrfs_trans_handle *trans,
 {
        struct rb_node *node;
        struct file_extent_hole *hole;
+       int found = 0;
        int ret = 0;
 
        node = rb_first(&rec->holes);
 
        while (node) {
+               found = 1;
                hole = rb_entry(node, struct file_extent_hole, node);
                ret = btrfs_punch_hole(trans, root, rec->ino,
                                       hole->start, hole->len);
@@ -2644,6 +2964,13 @@ static int repair_inode_discount_extent(struct btrfs_trans_handle *trans,
                        rec->errors &= ~I_ERR_FILE_EXTENT_DISCOUNT;
                node = rb_first(&rec->holes);
        }
+       /* special case for a file losing all its file extent */
+       if (!found) {
+               ret = btrfs_punch_hole(trans, root, rec->ino, 0,
+                                      round_up(rec->isize, root->sectorsize));
+               if (ret < 0)
+                       goto out;
+       }
        printf("Fixed discount file extents for inode: %llu in root: %llu\n",
               rec->ino, root->objectid);
 out:
@@ -2661,7 +2988,8 @@ static int try_repair_inode(struct btrfs_root *root, struct inode_record *rec)
                             I_ERR_LINK_COUNT_WRONG |
                             I_ERR_NO_INODE_ITEM |
                             I_ERR_FILE_EXTENT_ORPHAN |
-                            I_ERR_FILE_EXTENT_DISCOUNT)))
+                            I_ERR_FILE_EXTENT_DISCOUNT|
+                            I_ERR_FILE_NBYTES_WRONG)))
                return rec->errors;
 
        path = btrfs_alloc_path();
@@ -2693,6 +3021,8 @@ static int try_repair_inode(struct btrfs_root *root, struct inode_record *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);
+       if (!ret && rec->errors & I_ERR_FILE_NBYTES_WRONG)
+               ret = repair_inode_nbytes(trans, root, path, rec);
        btrfs_commit_transaction(trans, root);
        btrfs_free_path(path);
        return ret;
@@ -2720,7 +3050,7 @@ static int check_inode_recs(struct btrfs_root *root,
        /*
         * We need to record the highest inode number for later 'lost+found'
         * dir creation.
-        * We must select a ino not used/refered by any existing inode, or
+        * We must select an ino not used/referred by any existing inode, or
         * 'lost+found' ino may be a missing ino in a corrupted leaf,
         * this may cause 'lost+found' dir has wrong nlinks.
         */
@@ -2784,6 +3114,7 @@ static int check_inode_recs(struct btrfs_root *root,
                return err;
 
        rec = get_inode_rec(inode_cache, root_dirid, 0);
+       BUG_ON(IS_ERR(rec));
        if (rec) {
                ret = check_root_dir(rec);
                if (ret) {
@@ -2891,13 +3222,16 @@ static struct root_record *get_root_rec(struct cache_tree *root_cache,
                rec = container_of(cache, struct root_record, cache);
        } else {
                rec = calloc(1, sizeof(*rec));
+               if (!rec)
+                       return ERR_PTR(-ENOMEM);
                rec->objectid = objectid;
                INIT_LIST_HEAD(&rec->backrefs);
                rec->cache.start = objectid;
                rec->cache.size = 1;
 
                ret = insert_cache_extent(root_cache, &rec->cache);
-               BUG_ON(ret);
+               if (ret)
+                       return ERR_PTR(-EEXIST);
        }
        return rec;
 }
@@ -2917,8 +3251,9 @@ static struct root_backref *get_root_backref(struct root_record *rec,
                return backref;
        }
 
-       backref = malloc(sizeof(*backref) + namelen + 1);
-       memset(backref, 0, sizeof(*backref));
+       backref = calloc(1, sizeof(*backref) + namelen + 1);
+       if (!backref)
+               return NULL;
        backref->ref_root = ref_root;
        backref->dir = dir;
        backref->index = index;
@@ -2936,8 +3271,7 @@ static void free_root_record(struct cache_extent *cache)
 
        rec = container_of(cache, struct root_record, cache);
        while (!list_empty(&rec->backrefs)) {
-               backref = list_entry(rec->backrefs.next,
-                                    struct root_backref, list);
+               backref = to_root_backref(rec->backrefs.next);
                list_del(&backref->list);
                free(backref);
        }
@@ -2956,7 +3290,9 @@ static int add_root_backref(struct cache_tree *root_cache,
        struct root_backref *backref;
 
        rec = get_root_rec(root_cache, root_id);
+       BUG_ON(IS_ERR(rec));
        backref = get_root_backref(rec, ref_root, dir, index, name, namelen);
+       BUG_ON(!backref);
 
        backref->errors |= errors;
 
@@ -3061,6 +3397,7 @@ static int check_root_refs(struct btrfs_root *root,
        int errors = 0;
 
        rec = get_root_rec(root_cache, BTRFS_FS_TREE_OBJECTID);
+       BUG_ON(IS_ERR(rec));
        rec->found_ref = 1;
 
        /* fixme: this can not detect circular references */
@@ -3082,6 +3419,7 @@ static int check_root_refs(struct btrfs_root *root,
 
                                ref_root = get_root_rec(root_cache,
                                                        backref->ref_root);
+                               BUG_ON(IS_ERR(ref_root));
                                if (ref_root->found_ref > 0)
                                        continue;
 
@@ -3316,6 +3654,7 @@ static int check_fs_root(struct btrfs_root *root,
        struct orphan_data_extent *orphan;
        struct orphan_data_extent *tmp;
        enum btrfs_tree_block_status status;
+       struct node_refs nrefs;
 
        /*
         * Reuse the corrupt_block cache tree to record corrupted tree block
@@ -3328,6 +3667,7 @@ static int check_fs_root(struct btrfs_root *root,
 
        if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
                rec = get_root_rec(root_cache, root->root_key.objectid);
+               BUG_ON(IS_ERR(rec));
                if (btrfs_root_refs(root_item) > 0)
                        rec->found_root_item = 1;
        }
@@ -3336,6 +3676,7 @@ static int check_fs_root(struct btrfs_root *root,
        memset(&root_node, 0, sizeof(root_node));
        cache_tree_init(&root_node.root_cache);
        cache_tree_init(&root_node.inode_cache);
+       memset(&nrefs, 0, sizeof(nrefs));
 
        /* Move the orphan extent record to corresponding inode_record */
        list_for_each_entry_safe(orphan, tmp,
@@ -3344,6 +3685,7 @@ static int check_fs_root(struct btrfs_root *root,
 
                inode = get_inode_rec(&root_node.inode_cache, orphan->objectid,
                                      1);
+               BUG_ON(IS_ERR(inode));
                inode->errors |= I_ERR_FILE_EXTENT_ORPHAN;
                list_move(&orphan->list, &inode->orphan_extents);
        }
@@ -3384,7 +3726,7 @@ static int check_fs_root(struct btrfs_root *root,
        }
 
        while (1) {
-               wret = walk_down_tree(root, &path, wc, &level);
+               wret = walk_down_tree(root, &path, wc, &level, &nrefs);
                if (wret < 0)
                        ret = wret;
                if (wret != 0)
@@ -3469,6 +3811,11 @@ static int check_fs_roots(struct btrfs_root *root,
        int ret;
        int err = 0;
 
+       if (ctx.progress_enabled) {
+               ctx.tp = TASK_FS_ROOTS;
+               task_start(ctx.info);
+       }
+
        /*
         * Just in case we made any changes to the extent tree that weren't
         * reflected into the free space cache yet.
@@ -3545,27 +3892,28 @@ out:
        if (!cache_tree_empty(&wc.shared))
                fprintf(stderr, "warning line %d\n", __LINE__);
 
+       task_stop(ctx.info);
+
        return err;
 }
 
 static int all_backpointers_checked(struct extent_record *rec, int print_errs)
 {
-       struct list_head *cur = rec->backrefs.next;
+       struct rb_node *n;
        struct extent_backref *back;
        struct tree_backref *tback;
        struct data_backref *dback;
        u64 found = 0;
        int err = 0;
 
-       while(cur != &rec->backrefs) {
-               back = list_entry(cur, struct extent_backref, list);
-               cur = cur->next;
+       for (n = rb_first(&rec->backref_tree); n; n = rb_next(n)) {
+               back = rb_node_to_extent_backref(n);
                if (!back->found_extent_tree) {
                        err = 1;
                        if (!print_errs)
                                goto out;
                        if (back->is_data) {
-                               dback = (struct data_backref *)back;
+                               dback = to_data_backref(back);
                                fprintf(stderr, "Backref %llu %s %llu"
                                        " owner %llu offset %llu num_refs %lu"
                                        " not found in extent tree\n",
@@ -3579,7 +3927,7 @@ static int all_backpointers_checked(struct extent_record *rec, int print_errs)
                                        (unsigned long long)dback->offset,
                                        (unsigned long)dback->num_refs);
                        } else {
-                               tback = (struct tree_backref *)back;
+                               tback = to_tree_backref(back);
                                fprintf(stderr, "Backref %llu parent %llu"
                                        " root %llu not found in extent tree\n",
                                        (unsigned long long)rec->start,
@@ -3591,7 +3939,7 @@ static int all_backpointers_checked(struct extent_record *rec, int print_errs)
                        err = 1;
                        if (!print_errs)
                                goto out;
-                       tback = (struct tree_backref *)back;
+                       tback = to_tree_backref(back);
                        fprintf(stderr, "Backref %llu %s %llu not referenced back %p\n",
                                (unsigned long long)rec->start,
                                back->full_backref ? "parent" : "root",
@@ -3600,7 +3948,7 @@ static int all_backpointers_checked(struct extent_record *rec, int print_errs)
                                (unsigned long long)tback->root, back);
                }
                if (back->is_data) {
-                       dback = (struct data_backref *)back;
+                       dback = to_data_backref(back);
                        if (dback->found_ref != dback->num_refs) {
                                err = 1;
                                if (!print_errs)
@@ -3644,7 +3992,7 @@ static int all_backpointers_checked(struct extent_record *rec, int print_errs)
                if (!back->is_data) {
                        found += 1;
                } else {
-                       dback = (struct data_backref *)back;
+                       dback = to_data_backref(back);
                        found += dback->found_ref;
                }
        }
@@ -3662,17 +4010,16 @@ out:
        return err;
 }
 
-static int free_all_extent_backrefs(struct extent_record *rec)
+static void __free_one_backref(struct rb_node *node)
 {
-       struct extent_backref *back;
-       struct list_head *cur;
-       while (!list_empty(&rec->backrefs)) {
-               cur = rec->backrefs.next;
-               back = list_entry(cur, struct extent_backref, list);
-               list_del(cur);
-               free(back);
-       }
-       return 0;
+       struct extent_backref *back = rb_node_to_extent_backref(node);
+
+       free(back);
+}
+
+static void free_all_extent_backrefs(struct extent_record *rec)
+{
+       rb_free_nodes(&rec->backref_tree, __free_one_backref);
 }
 
 static void free_extent_record_cache(struct btrfs_fs_info *fs_info,
@@ -3698,7 +4045,8 @@ static int maybe_free_extent_rec(struct cache_tree *extent_cache,
        if (rec->content_checked && rec->owner_ref_checked &&
            rec->extent_item_refs == rec->refs && rec->refs > 0 &&
            rec->num_duplicates == 0 && !all_backpointers_checked(rec, 0) &&
-           !rec->bad_full_backref) {
+           !rec->bad_full_backref && !rec->crossing_stripes &&
+           !rec->wrong_chunk_type) {
                remove_cache_extent(extent_cache, &rec->cache);
                free_all_extent_backrefs(rec);
                list_del_init(&rec->list);
@@ -3711,7 +4059,7 @@ static int check_owner_ref(struct btrfs_root *root,
                            struct extent_record *rec,
                            struct extent_buffer *buf)
 {
-       struct extent_backref *node;
+       struct extent_backref *node, *tmp;
        struct tree_backref *back;
        struct btrfs_root *ref_root;
        struct btrfs_key key;
@@ -3721,14 +4069,15 @@ static int check_owner_ref(struct btrfs_root *root,
        int found = 0;
        int ret;
 
-       list_for_each_entry(node, &rec->backrefs, list) {
+       rbtree_postorder_for_each_entry_safe(node, tmp,
+                                            &rec->backref_tree, node) {
                if (node->is_data)
                        continue;
                if (!node->found_ref)
                        continue;
                if (node->full_backref)
                        continue;
-               back = (struct tree_backref *)node;
+               back = to_tree_backref(node);
                if (btrfs_header_owner(buf) == back->root)
                        return 0;
        }
@@ -3766,18 +4115,16 @@ static int check_owner_ref(struct btrfs_root *root,
 
 static int is_extent_tree_record(struct extent_record *rec)
 {
-       struct list_head *cur = rec->backrefs.next;
-       struct extent_backref *node;
+       struct extent_backref *ref, *tmp;
        struct tree_backref *back;
        int is_extent = 0;
 
-       while(cur != &rec->backrefs) {
-               node = list_entry(cur, struct extent_backref, list);
-               cur = cur->next;
-               if (node->is_data)
+       rbtree_postorder_for_each_entry_safe(ref, tmp,
+                                            &rec->backref_tree, node) {
+               if (ref->is_data)
                        return 0;
-               back = (struct tree_backref *)node;
-               if (node->full_backref)
+               back = to_tree_backref(ref);
+               if (ref->full_backref)
                        return 0;
                if (back->root == BTRFS_EXTENT_TREE_OBJECTID)
                        is_extent = 1;
@@ -4132,7 +4479,7 @@ static int check_block(struct btrfs_root *root,
                } else {
                        /*
                         * Signal to callers we need to start the scan over
-                        * again since we'll have cow'ed blocks.
+                        * again since we'll have cowed blocks.
                         */
                        ret = -EAGAIN;
                }
@@ -4151,38 +4498,40 @@ static int check_block(struct btrfs_root *root,
        return ret;
 }
 
+
 static struct tree_backref *find_tree_backref(struct extent_record *rec,
                                                u64 parent, u64 root)
 {
-       struct list_head *cur = rec->backrefs.next;
-       struct extent_backref *node;
-       struct tree_backref *back;
+       struct rb_node *node;
+       struct tree_backref *back = NULL;
+       struct tree_backref match = {
+               .node = {
+                       .is_data = 0,
+               },
+       };
 
-       while(cur != &rec->backrefs) {
-               node = list_entry(cur, struct extent_backref, list);
-               cur = cur->next;
-               if (node->is_data)
-                       continue;
-               back = (struct tree_backref *)node;
-               if (parent > 0) {
-                       if (!node->full_backref)
-                               continue;
-                       if (parent == back->parent)
-                               return back;
-               } else {
-                       if (node->full_backref)
-                               continue;
-                       if (back->root == root)
-                               return back;
-               }
+       if (parent) {
+               match.parent = parent;
+               match.node.full_backref = 1;
+       } else {
+               match.root = root;
        }
-       return NULL;
+
+       node = rb_search(&rec->backref_tree, &match.node.node,
+                        (rb_compare_keys)compare_extent_backref, NULL);
+       if (node)
+               back = to_tree_backref(rb_node_to_extent_backref(node));
+
+       return back;
 }
 
 static struct tree_backref *alloc_tree_backref(struct extent_record *rec,
                                                u64 parent, u64 root)
 {
        struct tree_backref *ref = malloc(sizeof(*ref));
+
+       if (!ref)
+               return NULL;
        memset(&ref->node, 0, sizeof(ref->node));
        if (parent > 0) {
                ref->parent = parent;
@@ -4191,7 +4540,7 @@ static struct tree_backref *alloc_tree_backref(struct extent_record *rec,
                ref->root = root;
                ref->node.full_backref = 0;
        }
-       list_add_tail(&ref->node.list, &rec->backrefs);
+       rb_insert(&rec->backref_tree, &ref->node.node, compare_extent_backref);
 
        return ref;
 }
@@ -4202,35 +4551,32 @@ static struct data_backref *find_data_backref(struct extent_record *rec,
                                                int found_ref,
                                                u64 disk_bytenr, u64 bytes)
 {
-       struct list_head *cur = rec->backrefs.next;
-       struct extent_backref *node;
-       struct data_backref *back;
+       struct rb_node *node;
+       struct data_backref *back = NULL;
+       struct data_backref match = {
+               .node = {
+                       .is_data = 1,
+               },
+               .owner = owner,
+               .offset = offset,
+               .bytes = bytes,
+               .found_ref = found_ref,
+               .disk_bytenr = disk_bytenr,
+       };
 
-       while(cur != &rec->backrefs) {
-               node = list_entry(cur, struct extent_backref, list);
-               cur = cur->next;
-               if (!node->is_data)
-                       continue;
-               back = (struct data_backref *)node;
-               if (parent > 0) {
-                       if (!node->full_backref)
-                               continue;
-                       if (parent == back->parent)
-                               return back;
-               } else {
-                       if (node->full_backref)
-                               continue;
-                       if (back->root == root && back->owner == owner &&
-                           back->offset == offset) {
-                               if (found_ref && node->found_ref &&
-                                   (back->bytes != bytes ||
-                                   back->disk_bytenr != disk_bytenr))
-                                       continue;
-                               return back;
-                       }
-               }
+       if (parent) {
+               match.parent = parent;
+               match.node.full_backref = 1;
+       } else {
+               match.root = root;
        }
-       return NULL;
+
+       node = rb_search(&rec->backref_tree, &match.node.node,
+                        (rb_compare_keys)compare_extent_backref, NULL);
+       if (node)
+               back = to_data_backref(rb_node_to_extent_backref(node));
+
+       return back;
 }
 
 static struct data_backref *alloc_data_backref(struct extent_record *rec,
@@ -4239,6 +4585,9 @@ static struct data_backref *alloc_data_backref(struct extent_record *rec,
                                                u64 max_size)
 {
        struct data_backref *ref = malloc(sizeof(*ref));
+
+       if (!ref)
+               return NULL;
        memset(&ref->node, 0, sizeof(ref->node));
        ref->node.is_data = 1;
 
@@ -4256,147 +4605,213 @@ static struct data_backref *alloc_data_backref(struct extent_record *rec,
        ref->bytes = max_size;
        ref->found_ref = 0;
        ref->num_refs = 0;
-       list_add_tail(&ref->node.list, &rec->backrefs);
+       rb_insert(&rec->backref_tree, &ref->node.node, compare_extent_backref);
        if (max_size > rec->max_size)
                rec->max_size = max_size;
        return ref;
 }
 
-static int add_extent_rec(struct cache_tree *extent_cache,
-                         struct btrfs_key *parent_key, u64 parent_gen,
-                         u64 start, u64 nr, u64 extent_item_refs,
-                         int is_root, int inc_ref, int set_checked,
-                         int metadata, int extent_rec, u64 max_size)
+/* Check if the type of extent matches with its chunk */
+static void check_extent_type(struct extent_record *rec)
 {
-       struct extent_record *rec;
-       struct cache_extent *cache;
-       int ret = 0;
-       int dup = 0;
+       struct btrfs_block_group_cache *bg_cache;
 
-       cache = lookup_cache_extent(extent_cache, start, nr);
-       if (cache) {
-               rec = container_of(cache, struct extent_record, cache);
-               if (inc_ref)
-                       rec->refs++;
-               if (rec->nr == 1)
-                       rec->nr = max(nr, max_size);
+       bg_cache = btrfs_lookup_first_block_group(global_info, rec->start);
+       if (!bg_cache)
+               return;
 
-               /*
-                * We need to make sure to reset nr to whatever the extent
-                * record says was the real size, this way we can compare it to
-                * the backrefs.
-                */
-               if (extent_rec) {
-                       if (start != rec->start || rec->found_rec) {
-                               struct extent_record *tmp;
+       /* data extent, check chunk directly*/
+       if (!rec->metadata) {
+               if (!(bg_cache->flags & BTRFS_BLOCK_GROUP_DATA))
+                       rec->wrong_chunk_type = 1;
+               return;
+       }
 
-                               dup = 1;
-                               if (list_empty(&rec->list))
-                                       list_add_tail(&rec->list,
-                                                     &duplicate_extents);
+       /* metadata extent, check the obvious case first */
+       if (!(bg_cache->flags & (BTRFS_BLOCK_GROUP_SYSTEM |
+                                BTRFS_BLOCK_GROUP_METADATA))) {
+               rec->wrong_chunk_type = 1;
+               return;
+       }
 
-                               /*
-                                * We have to do this song and dance in case we
-                                * find an extent record that falls inside of
-                                * our current extent record but does not have
-                                * the same objectid.
-                                */
-                               tmp = malloc(sizeof(*tmp));
-                               if (!tmp)
-                                       return -ENOMEM;
-                               tmp->start = start;
-                               tmp->max_size = max_size;
-                               tmp->nr = nr;
-                               tmp->found_rec = 1;
-                               tmp->metadata = metadata;
-                               tmp->extent_item_refs = extent_item_refs;
-                               INIT_LIST_HEAD(&tmp->list);
+       /*
+        * Check SYSTEM extent, as it's also marked as metadata, we can only
+        * make sure it's a SYSTEM extent by its backref
+        */
+       if (!RB_EMPTY_ROOT(&rec->backref_tree)) {
+               struct extent_backref *node;
+               struct tree_backref *tback;
+               u64 bg_type;
+
+               node = rb_node_to_extent_backref(rb_first(&rec->backref_tree));
+               if (node->is_data) {
+                       /* tree block shouldn't have data backref */
+                       rec->wrong_chunk_type = 1;
+                       return;
+               }
+               tback = container_of(node, struct tree_backref, node);
+
+               if (tback->root == BTRFS_CHUNK_TREE_OBJECTID)
+                       bg_type = BTRFS_BLOCK_GROUP_SYSTEM;
+               else
+                       bg_type = BTRFS_BLOCK_GROUP_METADATA;
+               if (!(bg_cache->flags & bg_type))
+                       rec->wrong_chunk_type = 1;
+       }
+}
+
+/*
+ * Allocate a new extent record, fill default values from @tmpl and insert int
+ * @extent_cache. Caller is supposed to make sure the [start,nr) is not in
+ * the cache, otherwise it fails.
+ */
+static int add_extent_rec_nolookup(struct cache_tree *extent_cache,
+               struct extent_record *tmpl)
+{
+       struct extent_record *rec;
+       int ret = 0;
+
+       rec = malloc(sizeof(*rec));
+       if (!rec)
+               return -ENOMEM;
+       rec->start = tmpl->start;
+       rec->max_size = tmpl->max_size;
+       rec->nr = max(tmpl->nr, tmpl->max_size);
+       rec->found_rec = tmpl->found_rec;
+       rec->content_checked = tmpl->content_checked;
+       rec->owner_ref_checked = tmpl->owner_ref_checked;
+       rec->num_duplicates = 0;
+       rec->metadata = tmpl->metadata;
+       rec->flag_block_full_backref = FLAG_UNSET;
+       rec->bad_full_backref = 0;
+       rec->crossing_stripes = 0;
+       rec->wrong_chunk_type = 0;
+       rec->is_root = tmpl->is_root;
+       rec->refs = tmpl->refs;
+       rec->extent_item_refs = tmpl->extent_item_refs;
+       rec->parent_generation = tmpl->parent_generation;
+       INIT_LIST_HEAD(&rec->backrefs);
+       INIT_LIST_HEAD(&rec->dups);
+       INIT_LIST_HEAD(&rec->list);
+       rec->backref_tree = RB_ROOT;
+       memcpy(&rec->parent_key, &tmpl->parent_key, sizeof(tmpl->parent_key));
+       rec->cache.start = tmpl->start;
+       rec->cache.size = tmpl->nr;
+       ret = insert_cache_extent(extent_cache, &rec->cache);
+       BUG_ON(ret);
+       bytes_used += rec->nr;
+
+       if (tmpl->metadata)
+               rec->crossing_stripes = check_crossing_stripes(rec->start,
+                               global_info->tree_root->nodesize);
+       check_extent_type(rec);
+       return ret;
+}
+
+/*
+ * Lookup and modify an extent, some values of @tmpl are interpreted verbatim,
+ * some are hints:
+ * - refs              - if found, increase refs
+ * - is_root           - if found, set
+ * - content_checked   - if found, set
+ * - owner_ref_checked - if found, set
+ *
+ * If not found, create a new one, initialize and insert.
+ */
+static int add_extent_rec(struct cache_tree *extent_cache,
+               struct extent_record *tmpl)
+{
+       struct extent_record *rec;
+       struct cache_extent *cache;
+       int ret = 0;
+       int dup = 0;
+
+       cache = lookup_cache_extent(extent_cache, tmpl->start, tmpl->nr);
+       if (cache) {
+               rec = container_of(cache, struct extent_record, cache);
+               if (tmpl->refs)
+                       rec->refs++;
+               if (rec->nr == 1)
+                       rec->nr = max(tmpl->nr, tmpl->max_size);
+
+               /*
+                * We need to make sure to reset nr to whatever the extent
+                * record says was the real size, this way we can compare it to
+                * the backrefs.
+                */
+               if (tmpl->found_rec) {
+                       if (tmpl->start != rec->start || rec->found_rec) {
+                               struct extent_record *tmp;
+
+                               dup = 1;
+                               if (list_empty(&rec->list))
+                                       list_add_tail(&rec->list,
+                                                     &duplicate_extents);
+
+                               /*
+                                * We have to do this song and dance in case we
+                                * find an extent record that falls inside of
+                                * our current extent record but does not have
+                                * the same objectid.
+                                */
+                               tmp = malloc(sizeof(*tmp));
+                               if (!tmp)
+                                       return -ENOMEM;
+                               tmp->start = tmpl->start;
+                               tmp->max_size = tmpl->max_size;
+                               tmp->nr = tmpl->nr;
+                               tmp->found_rec = 1;
+                               tmp->metadata = tmpl->metadata;
+                               tmp->extent_item_refs = tmpl->extent_item_refs;
+                               INIT_LIST_HEAD(&tmp->list);
                                list_add_tail(&tmp->list, &rec->dups);
                                rec->num_duplicates++;
                        } else {
-                               rec->nr = nr;
+                               rec->nr = tmpl->nr;
                                rec->found_rec = 1;
                        }
                }
 
-               if (extent_item_refs && !dup) {
+               if (tmpl->extent_item_refs && !dup) {
                        if (rec->extent_item_refs) {
                                fprintf(stderr, "block %llu rec "
                                        "extent_item_refs %llu, passed %llu\n",
-                                       (unsigned long long)start,
+                                       (unsigned long long)tmpl->start,
                                        (unsigned long long)
                                                        rec->extent_item_refs,
-                                       (unsigned long long)extent_item_refs);
+                                       (unsigned long long)tmpl->extent_item_refs);
                        }
-                       rec->extent_item_refs = extent_item_refs;
+                       rec->extent_item_refs = tmpl->extent_item_refs;
                }
-               if (is_root)
+               if (tmpl->is_root)
                        rec->is_root = 1;
-               if (set_checked) {
+               if (tmpl->content_checked)
                        rec->content_checked = 1;
+               if (tmpl->owner_ref_checked)
                        rec->owner_ref_checked = 1;
-               }
-
-               if (parent_key)
-                       btrfs_cpu_key_to_disk(&rec->parent_key, parent_key);
-               if (parent_gen)
-                       rec->parent_generation = parent_gen;
-
-               if (rec->max_size < max_size)
-                       rec->max_size = max_size;
+               memcpy(&rec->parent_key, &tmpl->parent_key,
+                               sizeof(tmpl->parent_key));
+               if (tmpl->parent_generation)
+                       rec->parent_generation = tmpl->parent_generation;
+               if (rec->max_size < tmpl->max_size)
+                       rec->max_size = tmpl->max_size;
 
+               /*
+                * A metadata extent can't cross stripe_len boundary, otherwise
+                * kernel scrub won't be able to handle it.
+                * As now stripe_len is fixed to BTRFS_STRIPE_LEN, just check
+                * it.
+                */
+               if (tmpl->metadata)
+                       rec->crossing_stripes = check_crossing_stripes(
+                               rec->start, global_info->tree_root->nodesize);
+               check_extent_type(rec);
                maybe_free_extent_rec(extent_cache, rec);
                return ret;
        }
-       rec = malloc(sizeof(*rec));
-       rec->start = start;
-       rec->max_size = max_size;
-       rec->nr = max(nr, max_size);
-       rec->found_rec = !!extent_rec;
-       rec->content_checked = 0;
-       rec->owner_ref_checked = 0;
-       rec->num_duplicates = 0;
-       rec->metadata = metadata;
-       rec->flag_block_full_backref = -1;
-       rec->bad_full_backref = 0;
-       INIT_LIST_HEAD(&rec->backrefs);
-       INIT_LIST_HEAD(&rec->dups);
-       INIT_LIST_HEAD(&rec->list);
-
-       if (is_root)
-               rec->is_root = 1;
-       else
-               rec->is_root = 0;
-
-       if (inc_ref)
-               rec->refs = 1;
-       else
-               rec->refs = 0;
-
-       if (extent_item_refs)
-               rec->extent_item_refs = extent_item_refs;
-       else
-               rec->extent_item_refs = 0;
 
-       if (parent_key)
-               btrfs_cpu_key_to_disk(&rec->parent_key, parent_key);
-       else
-               memset(&rec->parent_key, 0, sizeof(*parent_key));
-
-       if (parent_gen)
-               rec->parent_generation = parent_gen;
-       else
-               rec->parent_generation = 0;
+       ret = add_extent_rec_nolookup(extent_cache, tmpl);
 
-       rec->cache.start = start;
-       rec->cache.size = nr;
-       ret = insert_cache_extent(extent_cache, &rec->cache);
-       BUG_ON(ret);
-       bytes_used += nr;
-       if (set_checked) {
-               rec->content_checked = 1;
-               rec->owner_ref_checked = 1;
-       }
        return ret;
 }
 
@@ -4409,8 +4824,15 @@ static int add_tree_backref(struct cache_tree *extent_cache, u64 bytenr,
 
        cache = lookup_cache_extent(extent_cache, bytenr, 1);
        if (!cache) {
-               add_extent_rec(extent_cache, NULL, 0, bytenr,
-                              1, 0, 0, 0, 0, 1, 0, 0);
+               struct extent_record tmpl;
+
+               memset(&tmpl, 0, sizeof(tmpl));
+               tmpl.start = bytenr;
+               tmpl.nr = 1;
+               tmpl.metadata = 1;
+
+               add_extent_rec_nolookup(extent_cache, &tmpl);
+
                cache = lookup_cache_extent(extent_cache, bytenr, 1);
                if (!cache)
                        abort();
@@ -4422,8 +4844,10 @@ static int add_tree_backref(struct cache_tree *extent_cache, u64 bytenr,
        }
 
        back = find_tree_backref(rec, parent, root);
-       if (!back)
+       if (!back) {
                back = alloc_tree_backref(rec, parent, root);
+               BUG_ON(!back);
+       }
 
        if (found_ref) {
                if (back->node.found_ref) {
@@ -4444,6 +4868,7 @@ static int add_tree_backref(struct cache_tree *extent_cache, u64 bytenr,
                }
                back->node.found_extent_tree = 1;
        }
+       check_extent_type(rec);
        maybe_free_extent_rec(extent_cache, rec);
        return 0;
 }
@@ -4458,8 +4883,15 @@ static int add_data_backref(struct cache_tree *extent_cache, u64 bytenr,
 
        cache = lookup_cache_extent(extent_cache, bytenr, 1);
        if (!cache) {
-               add_extent_rec(extent_cache, NULL, 0, bytenr, 1, 0, 0, 0, 0,
-                              0, 0, max_size);
+               struct extent_record tmpl;
+
+               memset(&tmpl, 0, sizeof(tmpl));
+               tmpl.start = bytenr;
+               tmpl.nr = 1;
+               tmpl.max_size = max_size;
+
+               add_extent_rec_nolookup(extent_cache, &tmpl);
+
                cache = lookup_cache_extent(extent_cache, bytenr, 1);
                if (!cache)
                        abort();
@@ -4481,9 +4913,11 @@ static int add_data_backref(struct cache_tree *extent_cache, u64 bytenr,
         */
        back = find_data_backref(rec, parent, root, owner, offset, found_ref,
                                 bytenr, max_size);
-       if (!back)
+       if (!back) {
                back = alloc_data_backref(rec, parent, root, owner, offset,
                                          max_size);
+               BUG_ON(!back);
+       }
 
        if (found_ref) {
                BUG_ON(num_refs != 1);
@@ -4713,14 +5147,12 @@ struct chunk_record *btrfs_new_chunk_record(struct extent_buffer *leaf,
        ptr = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
        num_stripes = btrfs_chunk_num_stripes(leaf, ptr);
 
-       rec = malloc(btrfs_chunk_record_size(num_stripes));
+       rec = calloc(1, btrfs_chunk_record_size(num_stripes));
        if (!rec) {
                fprintf(stderr, "memory allocation failed\n");
                exit(-1);
        }
 
-       memset(rec, 0, btrfs_chunk_record_size(num_stripes));
-
        INIT_LIST_HEAD(&rec->list);
        INIT_LIST_HEAD(&rec->dextents);
        rec->bg_rec = NULL;
@@ -4818,12 +5250,11 @@ btrfs_new_block_group_record(struct extent_buffer *leaf, struct btrfs_key *key,
        struct btrfs_block_group_item *ptr;
        struct block_group_record *rec;
 
-       rec = malloc(sizeof(*rec));
+       rec = calloc(1, sizeof(*rec));
        if (!rec) {
                fprintf(stderr, "memory allocation failed\n");
                exit(-1);
        }
-       memset(rec, 0, sizeof(*rec));
 
        rec->cache.start = key->objectid;
        rec->cache.size = key->offset;
@@ -4867,12 +5298,11 @@ btrfs_new_device_extent_record(struct extent_buffer *leaf,
        struct device_extent_record *rec;
        struct btrfs_dev_extent *ptr;
 
-       rec = malloc(sizeof(*rec));
+       rec = calloc(1, sizeof(*rec));
        if (!rec) {
                fprintf(stderr, "memory allocation failed\n");
                exit(-1);
        }
-       memset(rec, 0, sizeof(*rec));
 
        rec->cache.objectid = key->objectid;
        rec->cache.start = key->offset;
@@ -4926,6 +5356,7 @@ static int process_extent_item(struct btrfs_root *root,
        struct btrfs_extent_data_ref *dref;
        struct btrfs_shared_data_ref *sref;
        struct btrfs_key key;
+       struct extent_record tmpl;
        unsigned long end;
        unsigned long ptr;
        int type;
@@ -4939,7 +5370,7 @@ static int process_extent_item(struct btrfs_root *root,
 
        if (key.type == BTRFS_METADATA_ITEM_KEY) {
                metadata = 1;
-               num_bytes = root->leafsize;
+               num_bytes = root->nodesize;
        } else {
                num_bytes = key.offset;
        }
@@ -4953,16 +5384,32 @@ static int process_extent_item(struct btrfs_root *root,
 #else
                BUG();
 #endif
-               return add_extent_rec(extent_cache, NULL, 0, key.objectid,
-                                     num_bytes, refs, 0, 0, 0, metadata, 1,
-                                     num_bytes);
+               memset(&tmpl, 0, sizeof(tmpl));
+               tmpl.start = key.objectid;
+               tmpl.nr = num_bytes;
+               tmpl.extent_item_refs = refs;
+               tmpl.metadata = metadata;
+               tmpl.found_rec = 1;
+               tmpl.max_size = num_bytes;
+
+               return add_extent_rec(extent_cache, &tmpl);
        }
 
        ei = btrfs_item_ptr(eb, slot, struct btrfs_extent_item);
        refs = btrfs_extent_refs(eb, ei);
+       if (btrfs_extent_flags(eb, ei) & BTRFS_EXTENT_FLAG_TREE_BLOCK)
+               metadata = 1;
+       else
+               metadata = 0;
 
-       add_extent_rec(extent_cache, NULL, 0, key.objectid, num_bytes,
-                      refs, 0, 0, 0, metadata, 1, num_bytes);
+       memset(&tmpl, 0, sizeof(tmpl));
+       tmpl.start = key.objectid;
+       tmpl.nr = num_bytes;
+       tmpl.extent_item_refs = refs;
+       tmpl.metadata = metadata;
+       tmpl.found_rec = 1;
+       tmpl.max_size = num_bytes;
+       add_extent_rec(extent_cache, &tmpl);
 
        ptr = (unsigned long)(ei + 1);
        if (btrfs_extent_flags(eb, ei) & BTRFS_EXTENT_FLAG_TREE_BLOCK &&
@@ -5155,7 +5602,7 @@ static int verify_space_cache(struct btrfs_root *root,
                        if (key.type == BTRFS_EXTENT_ITEM_KEY)
                                last = key.objectid + key.offset;
                        else
-                               last = key.objectid + root->leafsize;
+                               last = key.objectid + root->nodesize;
                        path->slots[0]++;
                        continue;
                }
@@ -5167,7 +5614,7 @@ static int verify_space_cache(struct btrfs_root *root,
                if (key.type == BTRFS_EXTENT_ITEM_KEY)
                        last = key.objectid + key.offset;
                else
-                       last = key.objectid + root->leafsize;
+                       last = key.objectid + root->nodesize;
                path->slots[0]++;
        }
 
@@ -5204,6 +5651,11 @@ static int check_space_cache(struct btrfs_root *root)
                return 0;
        }
 
+       if (ctx.progress_enabled) {
+               ctx.tp = TASK_FREE_SPACE;
+               task_start(ctx.info);
+       }
+
        while (1) {
                cache = btrfs_lookup_first_block_group(root->fs_info, start);
                if (!cache)
@@ -5220,53 +5672,41 @@ static int check_space_cache(struct btrfs_root *root)
                        btrfs_remove_free_space_cache(cache);
                }
 
-               ret = load_free_space_cache(root->fs_info, cache);
-               if (!ret)
-                       continue;
+               if (btrfs_fs_compat_ro(root->fs_info,
+                                      BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE)) {
+                       ret = exclude_super_stripes(root, cache);
+                       if (ret) {
+                               fprintf(stderr, "could not exclude super stripes: %s\n",
+                                       strerror(-ret));
+                               error++;
+                               continue;
+                       }
+                       ret = load_free_space_tree(root->fs_info, cache);
+                       free_excluded_extents(root, cache);
+                       if (ret < 0) {
+                               fprintf(stderr, "could not load free space tree: %s\n",
+                                       strerror(-ret));
+                               error++;
+                               continue;
+                       }
+                       error += ret;
+               } else {
+                       ret = load_free_space_cache(root->fs_info, cache);
+                       if (!ret)
+                               continue;
+               }
 
                ret = verify_space_cache(root, cache);
                if (ret) {
-                       fprintf(stderr, "cache appears valid but isnt %Lu\n",
+                       fprintf(stderr, "cache appears valid but isn't %Lu\n",
                                cache->key.objectid);
                        error++;
                }
        }
 
-       return error ? -EINVAL : 0;
-}
-
-static int read_extent_data(struct btrfs_root *root, char *data,
-                       u64 logical, u64 *len, int mirror)
-{
-       u64 offset = 0;
-       struct btrfs_multi_bio *multi = NULL;
-       struct btrfs_fs_info *info = root->fs_info;
-       struct btrfs_device *device;
-       int ret = 0;
-       u64 max_len = *len;
-
-       ret = btrfs_map_block(&info->mapping_tree, READ, logical, len,
-                             &multi, mirror, NULL);
-       if (ret) {
-               fprintf(stderr, "Couldn't map the block %llu\n",
-                               logical + offset);
-               goto err;
-       }
-       device = multi->stripes[0].dev;
-
-       if (device->fd == 0)
-               goto err;
-       if (*len > max_len)
-               *len = max_len;
+       task_stop(ctx.info);
 
-       ret = pread64(device->fd, data, *len, multi->stripes[0].physical);
-       if (ret != *len)
-               ret = -EIO;
-       else
-               ret = 0;
-err:
-       kfree(multi);
-       return ret;
+       return error ? -EINVAL : 0;
 }
 
 static int check_extent_csums(struct btrfs_root *root, u64 bytenr,
@@ -5348,7 +5788,7 @@ static int check_extent_exists(struct btrfs_root *root, u64 bytenr,
 
        path = btrfs_alloc_path();
        if (!path) {
-               fprintf(stderr, "Error allocing path\n");
+               fprintf(stderr, "Error allocating path\n");
                return -ENOMEM;
        }
 
@@ -5381,7 +5821,7 @@ again:
 
        /*
         * Block group items come before extent items if they have the same
-        * bytenr, so walk back one more just in case.  Dear future traveler,
+        * bytenr, so walk back one more just in case.  Dear future traveller,
         * first congrats on mastering time travel.  Now if it's not too much
         * trouble could you go back to 2006 and tell Chris to make the
         * BLOCK_GROUP_ITEM_KEY (and BTRFS_*_REF_KEY) lower than the
@@ -5590,7 +6030,7 @@ static int is_dropped_key(struct btrfs_key *key,
  * 1) If BTRFS_HEADER_FLAG_RELOC is set then we have FULL_BACKREF set.
  * 2) If btrfs_header_owner(buf) no longer points to buf then we have
  *     FULL_BACKREF set.
- * 3) We cow'ed the block walking down a reloc tree.  This is impossible to tell
+ * 3) We cowed the block walking down a reloc tree.  This is impossible to tell
  *    if it happened after the relocation occurred since we'll have dropped the
  *    reloc root, so it's entirely possible to have FULL_BACKREF set on buf and
  *    have no real way to know for sure.
@@ -5644,13 +6084,13 @@ static int calc_extent_flag(struct btrfs_root *root,
                goto full_backref;
 normal:
        *flags = 0;
-       if (rec->flag_block_full_backref != -1 &&
+       if (rec->flag_block_full_backref != FLAG_UNSET &&
            rec->flag_block_full_backref != 0)
                rec->bad_full_backref = 1;
        return 0;
 full_backref:
        *flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
-       if (rec->flag_block_full_backref != -1 &&
+       if (rec->flag_block_full_backref != FLAG_UNSET &&
            rec->flag_block_full_backref != 1)
                rec->bad_full_backref = 1;
        return 0;
@@ -5932,8 +6372,10 @@ static int run_next_block(struct btrfs_root *root,
                        btrfs_item_key_to_cpu(buf, &first_key, 0);
                level = btrfs_header_level(buf);
                for (i = 0; i < nritems; i++) {
+                       struct extent_record tmpl;
+
                        ptr = btrfs_node_blockptr(buf, i);
-                       size = btrfs_level_size(root, level - 1);
+                       size = root->nodesize;
                        btrfs_node_key_to_cpu(buf, &key, i);
                        if (ri != NULL) {
                                if ((level == ri->drop_level)
@@ -5941,10 +6383,16 @@ static int run_next_block(struct btrfs_root *root,
                                        continue;
                                }
                        }
-                       ret = add_extent_rec(extent_cache, &key,
-                                            btrfs_node_ptr_generation(buf, i),
-                                            ptr, size, 0, 0, 1, 0, 1, 0,
-                                            size);
+
+                       memset(&tmpl, 0, sizeof(tmpl));
+                       btrfs_cpu_key_to_disk(&tmpl.parent_key, &key);
+                       tmpl.parent_generation = btrfs_node_ptr_generation(buf, i);
+                       tmpl.start = ptr;
+                       tmpl.nr = size;
+                       tmpl.refs = 1;
+                       tmpl.metadata = 1;
+                       tmpl.max_size = size;
+                       ret = add_extent_rec(extent_cache, &tmpl);
                        BUG_ON(ret);
 
                        add_tree_backref(extent_cache, ptr, parent, owner, 1);
@@ -5980,12 +6428,21 @@ static int add_root_to_pending(struct extent_buffer *buf,
                               struct cache_tree *nodes,
                               u64 objectid)
 {
+       struct extent_record tmpl;
+
        if (btrfs_header_level(buf) > 0)
                add_pending(nodes, seen, buf->start, buf->len);
        else
                add_pending(pending, seen, buf->start, buf->len);
-       add_extent_rec(extent_cache, NULL, 0, buf->start, buf->len,
-                      0, 1, 1, 0, 1, 0, buf->len);
+
+       memset(&tmpl, 0, sizeof(tmpl));
+       tmpl.start = buf->start;
+       tmpl.nr = buf->len;
+       tmpl.is_root = 1;
+       tmpl.refs = 1;
+       tmpl.metadata = 1;
+       tmpl.max_size = buf->len;
+       add_extent_rec(extent_cache, &tmpl);
 
        if (objectid == BTRFS_TREE_RELOC_OBJECTID ||
            btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
@@ -6039,7 +6496,7 @@ static int free_extent_hook(struct btrfs_trans_handle *trans,
                        back->node.found_extent_tree = 0;
 
                if (!back->node.found_extent_tree && back->node.found_ref) {
-                       list_del(&back->node.list);
+                       rb_erase(&back->node.node, &rec->backref_tree);
                        free(back);
                }
        } else {
@@ -6058,7 +6515,7 @@ static int free_extent_hook(struct btrfs_trans_handle *trans,
                        back->node.found_extent_tree = 0;
                }
                if (!back->node.found_extent_tree && back->node.found_ref) {
-                       list_del(&back->node.list);
+                       rb_erase(&back->node.node, &rec->backref_tree);
                        free(back);
                }
        }
@@ -6134,7 +6591,7 @@ static int delete_extent_records(struct btrfs_trans_handle *trans,
                if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
                    found_key.type == BTRFS_METADATA_ITEM_KEY) {
                        u64 bytes = (found_key.type == BTRFS_EXTENT_ITEM_KEY) ?
-                               found_key.offset : root->leafsize;
+                               found_key.offset : root->nodesize;
 
                        ret = btrfs_update_block_group(trans, root, bytenr,
                                                       bytes, 0, 0);
@@ -6169,7 +6626,7 @@ static int record_extent(struct btrfs_trans_handle *trans,
 
        if (!back->is_data)
                rec->max_size = max_t(u64, rec->max_size,
-                                   info->extent_root->leafsize);
+                                   info->extent_root->nodesize);
 
        if (!allocated) {
                u32 item_size = sizeof(*ei);
@@ -6199,7 +6656,7 @@ static int record_extent(struct btrfs_trans_handle *trans,
                } else {
                        struct btrfs_disk_key copy_key;;
 
-                       tback = (struct tree_backref *)back;
+                       tback = to_tree_backref(back);
                        bi = (struct btrfs_tree_block_info *)(ei + 1);
                        memset_extent_buffer(leaf, 0, (unsigned long)bi,
                                             sizeof(*bi));
@@ -6228,7 +6685,7 @@ static int record_extent(struct btrfs_trans_handle *trans,
                u64 parent;
                int i;
 
-               dback = (struct data_backref *)back;
+               dback = to_data_backref(back);
                if (back->full_backref)
                        parent = dback->parent;
                else
@@ -6266,7 +6723,7 @@ static int record_extent(struct btrfs_trans_handle *trans,
        } else {
                u64 parent;
 
-               tback = (struct tree_backref *)back;
+               tback = to_tree_backref(back);
                if (back->full_backref)
                        parent = tback->parent;
                else
@@ -6279,21 +6736,11 @@ static int record_extent(struct btrfs_trans_handle *trans,
                        "start %llu len %llu parent %llu root %llu\n",
                        rec->start, rec->max_size, parent, tback->root);
        }
-       if (ret)
-               goto fail;
 fail:
        btrfs_release_path(path);
        return ret;
 }
 
-struct extent_entry {
-       u64 bytenr;
-       u64 bytes;
-       int count;
-       int broken;
-       struct list_head list;
-};
-
 static struct extent_entry *find_entry(struct list_head *entries,
                                       u64 bytenr, u64 bytes)
 {
@@ -6505,7 +6952,7 @@ out:
 static int verify_backrefs(struct btrfs_fs_info *info, struct btrfs_path *path,
                           struct extent_record *rec)
 {
-       struct extent_backref *back;
+       struct extent_backref *back, *tmp;
        struct data_backref *dback;
        struct extent_entry *entry, *best = NULL;
        LIST_HEAD(entries);
@@ -6521,11 +6968,12 @@ static int verify_backrefs(struct btrfs_fs_info *info, struct btrfs_path *path,
        if (rec->metadata)
                return 0;
 
-       list_for_each_entry(back, &rec->backrefs, list) {
+       rbtree_postorder_for_each_entry_safe(back, tmp,
+                                            &rec->backref_tree, node) {
                if (back->full_backref || !back->is_data)
                        continue;
 
-               dback = (struct data_backref *)back;
+               dback = to_data_backref(back);
 
                /*
                 * We only pay attention to backrefs that we found a real
@@ -6647,11 +7095,12 @@ static int verify_backrefs(struct btrfs_fs_info *info, struct btrfs_path *path,
         * Ok great we all agreed on an extent record, let's go find the real
         * references and fix up the ones that don't match.
         */
-       list_for_each_entry(back, &rec->backrefs, list) {
+       rbtree_postorder_for_each_entry_safe(back, tmp,
+                                            &rec->backref_tree, node) {
                if (back->full_backref || !back->is_data)
                        continue;
 
-               dback = (struct data_backref *)back;
+               dback = to_data_backref(back);
 
                /*
                 * Still ignoring backrefs that don't have a real ref attached
@@ -6715,7 +7164,7 @@ static int process_duplicates(struct btrfs_root *root,
         */
        remove_cache_extent(extent_cache, &rec->cache);
 
-       good = list_entry(rec->dups.next, struct extent_record, list);
+       good = to_extent_record(rec->dups.next);
        list_del_init(&good->list);
        INIT_LIST_HEAD(&good->backrefs);
        INIT_LIST_HEAD(&good->dups);
@@ -6792,7 +7241,7 @@ static int delete_duplicate_records(struct btrfs_root *root,
 
                if (tmp->start + tmp->nr < good->start + good->nr) {
                        fprintf(stderr, "Ok we have overlapping extents that "
-                               "aren't completely covered by eachother, this "
+                               "aren't completely covered by each other, this "
                                "is going to require more careful thought.  "
                                "The extents are [%Lu-%Lu] and [%Lu-%Lu]\n",
                                tmp->start, tmp->nr, good->start, good->nr);
@@ -6849,7 +7298,7 @@ static int delete_duplicate_records(struct btrfs_root *root,
                ret = err;
 out:
        while (!list_empty(&delete_list)) {
-               tmp = list_entry(delete_list.next, struct extent_record, list);
+               tmp = to_extent_record(delete_list.next);
                list_del_init(&tmp->list);
                if (tmp == rec)
                        continue;
@@ -6857,7 +7306,7 @@ out:
        }
 
        while (!list_empty(&rec->dups)) {
-               tmp = list_entry(rec->dups.next, struct extent_record, list);
+               tmp = to_extent_record(rec->dups.next);
                list_del_init(&tmp->list);
                free(tmp);
        }
@@ -6876,7 +7325,7 @@ static int find_possible_backrefs(struct btrfs_fs_info *info,
                                  struct extent_record *rec)
 {
        struct btrfs_root *root;
-       struct extent_backref *back;
+       struct extent_backref *back, *tmp;
        struct data_backref *dback;
        struct cache_extent *cache;
        struct btrfs_file_extent_item *fi;
@@ -6884,12 +7333,13 @@ static int find_possible_backrefs(struct btrfs_fs_info *info,
        u64 bytenr, bytes;
        int ret;
 
-       list_for_each_entry(back, &rec->backrefs, list) {
+       rbtree_postorder_for_each_entry_safe(back, tmp,
+                                            &rec->backref_tree, node) {
                /* Don't care about full backrefs (poor unloved backrefs) */
                if (back->full_backref || !back->is_data)
                        continue;
 
-               dback = (struct data_backref *)back;
+               dback = to_data_backref(back);
 
                /* We found this one, we don't need to do a lookup */
                if (dback->found_ref)
@@ -6972,7 +7422,7 @@ static int record_orphan_data_extents(struct btrfs_fs_info *fs_info,
 {
        struct btrfs_key key;
        struct btrfs_root *dest_root;
-       struct extent_backref *back;
+       struct extent_backref *back, *tmp;
        struct data_backref *dback;
        struct orphan_data_extent *orphan;
        struct btrfs_path *path;
@@ -6984,11 +7434,12 @@ static int record_orphan_data_extents(struct btrfs_fs_info *fs_info,
        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;
-       list_for_each_entry(back, &rec->backrefs, list) {
+       rbtree_postorder_for_each_entry_safe(back, tmp,
+                                            &rec->backref_tree, node) {
                if (back->full_backref || !back->is_data ||
                    !back->found_extent_tree)
                        continue;
-               dback = (struct data_backref *)back;
+               dback = to_data_backref(back);
                if (dback->found_ref)
                        continue;
                key.objectid = dback->root;
@@ -7051,9 +7502,8 @@ static int fixup_extent_refs(struct btrfs_fs_info *info,
        struct btrfs_trans_handle *trans = NULL;
        int ret;
        struct btrfs_path *path;
-       struct list_head *cur = rec->backrefs.next;
        struct cache_extent *cache;
-       struct extent_backref *back;
+       struct extent_backref *back, *tmp;
        int allocated = 0;
        u64 flags = 0;
 
@@ -7104,10 +7554,8 @@ static int fixup_extent_refs(struct btrfs_fs_info *info,
        }
 
        /* step three, recreate all the refs we did find */
-       while(cur != &rec->backrefs) {
-               back = list_entry(cur, struct extent_backref, list);
-               cur = cur->next;
-
+       rbtree_postorder_for_each_entry_safe(back, tmp,
+                                            &rec->backref_tree, node) {
                /*
                 * if we didn't find any references, don't create a
                 * new extent record
@@ -7362,8 +7810,7 @@ static int check_extent_refs(struct btrfs_root *root,
         * belong to a different extent item and not the weird duplicate one.
         */
        while (repair && !list_empty(&duplicate_extents)) {
-               rec = list_entry(duplicate_extents.next, struct extent_record,
-                                list);
+               rec = to_extent_record(duplicate_extents.next);
                list_del_init(&rec->list);
 
                /* Sometimes we can find a backref before we find an actual
@@ -7476,6 +7923,26 @@ static int check_extent_refs(struct btrfs_root *root,
                        err = 1;
                        cur_err = 1;
                }
+               /*
+                * Although it's not a extent ref's problem, we reuse this
+                * routine for error reporting.
+                * No repair function yet.
+                */
+               if (rec->crossing_stripes) {
+                       fprintf(stderr,
+                               "bad metadata [%llu, %llu) crossing stripe boundary\n",
+                               rec->start, rec->start + rec->max_size);
+                       err = 1;
+                       cur_err = 1;
+               }
+
+               if (rec->wrong_chunk_type) {
+                       fprintf(stderr,
+                               "bad extent [%llu, %llu), type mismatch with chunk\n",
+                               rec->start, rec->start + rec->max_size);
+                       err = 1;
+                       cur_err = 1;
+               }
 
                remove_cache_extent(extent_cache, cache);
                free_all_extent_backrefs(rec);
@@ -7870,213 +8337,744 @@ static int deal_root_from_list(struct list_head *list,
        return ret;
 }
 
-static int check_chunks_and_extents(struct btrfs_root *root)
+static int check_chunks_and_extents(struct btrfs_root *root)
+{
+       struct rb_root dev_cache;
+       struct cache_tree chunk_cache;
+       struct block_group_tree block_group_cache;
+       struct device_extent_tree dev_extent_cache;
+       struct cache_tree extent_cache;
+       struct cache_tree seen;
+       struct cache_tree pending;
+       struct cache_tree reada;
+       struct cache_tree nodes;
+       struct extent_io_tree excluded_extents;
+       struct cache_tree corrupt_blocks;
+       struct btrfs_path path;
+       struct btrfs_key key;
+       struct btrfs_key found_key;
+       int ret, err = 0;
+       struct block_info *bits;
+       int bits_nr;
+       struct extent_buffer *leaf;
+       int slot;
+       struct btrfs_root_item ri;
+       struct list_head dropping_trees;
+       struct list_head normal_trees;
+       struct btrfs_root *root1;
+       u64 objectid;
+       u32 level_size;
+       u8 level;
+
+       dev_cache = RB_ROOT;
+       cache_tree_init(&chunk_cache);
+       block_group_tree_init(&block_group_cache);
+       device_extent_tree_init(&dev_extent_cache);
+
+       cache_tree_init(&extent_cache);
+       cache_tree_init(&seen);
+       cache_tree_init(&pending);
+       cache_tree_init(&nodes);
+       cache_tree_init(&reada);
+       cache_tree_init(&corrupt_blocks);
+       extent_io_tree_init(&excluded_extents);
+       INIT_LIST_HEAD(&dropping_trees);
+       INIT_LIST_HEAD(&normal_trees);
+
+       if (repair) {
+               root->fs_info->excluded_extents = &excluded_extents;
+               root->fs_info->fsck_extent_cache = &extent_cache;
+               root->fs_info->free_extent_hook = free_extent_hook;
+               root->fs_info->corrupt_blocks = &corrupt_blocks;
+       }
+
+       bits_nr = 1024;
+       bits = malloc(bits_nr * sizeof(struct block_info));
+       if (!bits) {
+               perror("malloc");
+               exit(1);
+       }
+
+       if (ctx.progress_enabled) {
+               ctx.tp = TASK_EXTENTS;
+               task_start(ctx.info);
+       }
+
+again:
+       root1 = root->fs_info->tree_root;
+       level = btrfs_header_level(root1->node);
+       ret = add_root_item_to_list(&normal_trees, root1->root_key.objectid,
+                                   root1->node->start, 0, level, 0,
+                                   root1->nodesize, NULL);
+       if (ret < 0)
+               goto out;
+       root1 = root->fs_info->chunk_root;
+       level = btrfs_header_level(root1->node);
+       ret = add_root_item_to_list(&normal_trees, root1->root_key.objectid,
+                                   root1->node->start, 0, level, 0,
+                                   root1->nodesize, NULL);
+       if (ret < 0)
+               goto out;
+       btrfs_init_path(&path);
+       key.offset = 0;
+       key.objectid = 0;
+       btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+       ret = btrfs_search_slot(NULL, root->fs_info->tree_root,
+                                       &key, &path, 0, 0);
+       if (ret < 0)
+               goto out;
+       while(1) {
+               leaf = path.nodes[0];
+               slot = path.slots[0];
+               if (slot >= btrfs_header_nritems(path.nodes[0])) {
+                       ret = btrfs_next_leaf(root, &path);
+                       if (ret != 0)
+                               break;
+                       leaf = path.nodes[0];
+                       slot = path.slots[0];
+               }
+               btrfs_item_key_to_cpu(leaf, &found_key, path.slots[0]);
+               if (btrfs_key_type(&found_key) == BTRFS_ROOT_ITEM_KEY) {
+                       unsigned long offset;
+                       u64 last_snapshot;
+
+                       offset = btrfs_item_ptr_offset(leaf, path.slots[0]);
+                       read_extent_buffer(leaf, &ri, offset, sizeof(ri));
+                       last_snapshot = btrfs_root_last_snapshot(&ri);
+                       if (btrfs_disk_key_objectid(&ri.drop_progress) == 0) {
+                               level = btrfs_root_level(&ri);
+                               level_size = root->nodesize;
+                               ret = add_root_item_to_list(&normal_trees,
+                                               found_key.objectid,
+                                               btrfs_root_bytenr(&ri),
+                                               last_snapshot, level,
+                                               0, level_size, NULL);
+                               if (ret < 0)
+                                       goto out;
+                       } else {
+                               level = btrfs_root_level(&ri);
+                               level_size = root->nodesize;
+                               objectid = found_key.objectid;
+                               btrfs_disk_key_to_cpu(&found_key,
+                                                     &ri.drop_progress);
+                               ret = add_root_item_to_list(&dropping_trees,
+                                               objectid,
+                                               btrfs_root_bytenr(&ri),
+                                               last_snapshot, level,
+                                               ri.drop_level,
+                                               level_size, &found_key);
+                               if (ret < 0)
+                                       goto out;
+                       }
+               }
+               path.slots[0]++;
+       }
+       btrfs_release_path(&path);
+
+       /*
+        * check_block can return -EAGAIN if it fixes something, please keep
+        * this in mind when dealing with return values from these functions, if
+        * we get -EAGAIN we want to fall through and restart the loop.
+        */
+       ret = deal_root_from_list(&normal_trees, root, bits, bits_nr, &pending,
+                                 &seen, &reada, &nodes, &extent_cache,
+                                 &chunk_cache, &dev_cache, &block_group_cache,
+                                 &dev_extent_cache);
+       if (ret < 0) {
+               if (ret == -EAGAIN)
+                       goto loop;
+               goto out;
+       }
+       ret = deal_root_from_list(&dropping_trees, root, bits, bits_nr,
+                                 &pending, &seen, &reada, &nodes,
+                                 &extent_cache, &chunk_cache, &dev_cache,
+                                 &block_group_cache, &dev_extent_cache);
+       if (ret < 0) {
+               if (ret == -EAGAIN)
+                       goto loop;
+               goto out;
+       }
+
+       ret = check_chunks(&chunk_cache, &block_group_cache,
+                          &dev_extent_cache, NULL, NULL, NULL, 0);
+       if (ret) {
+               if (ret == -EAGAIN)
+                       goto loop;
+               err = ret;
+       }
+
+       ret = check_extent_refs(root, &extent_cache);
+       if (ret < 0) {
+               if (ret == -EAGAIN)
+                       goto loop;
+               goto out;
+       }
+
+       ret = check_devices(&dev_cache, &dev_extent_cache);
+       if (ret && err)
+               ret = err;
+
+out:
+       task_stop(ctx.info);
+       if (repair) {
+               free_corrupt_blocks_tree(root->fs_info->corrupt_blocks);
+               extent_io_tree_cleanup(&excluded_extents);
+               root->fs_info->fsck_extent_cache = NULL;
+               root->fs_info->free_extent_hook = NULL;
+               root->fs_info->corrupt_blocks = NULL;
+               root->fs_info->excluded_extents = NULL;
+       }
+       free(bits);
+       free_chunk_cache_tree(&chunk_cache);
+       free_device_cache_tree(&dev_cache);
+       free_block_group_tree(&block_group_cache);
+       free_device_extent_tree(&dev_extent_cache);
+       free_extent_cache_tree(&seen);
+       free_extent_cache_tree(&pending);
+       free_extent_cache_tree(&reada);
+       free_extent_cache_tree(&nodes);
+       return ret;
+loop:
+       free_corrupt_blocks_tree(root->fs_info->corrupt_blocks);
+       free_extent_cache_tree(&seen);
+       free_extent_cache_tree(&pending);
+       free_extent_cache_tree(&reada);
+       free_extent_cache_tree(&nodes);
+       free_chunk_cache_tree(&chunk_cache);
+       free_block_group_tree(&block_group_cache);
+       free_device_cache_tree(&dev_cache);
+       free_device_extent_tree(&dev_extent_cache);
+       free_extent_record_cache(root->fs_info, &extent_cache);
+       free_root_item_list(&normal_trees);
+       free_root_item_list(&dropping_trees);
+       extent_io_tree_cleanup(&excluded_extents);
+       goto again;
+}
+
+/*
+ * Check backrefs of a tree block given by @bytenr or @eb.
+ *
+ * @root:      the root containing the @bytenr or @eb
+ * @eb:                tree block extent buffer, can be NULL
+ * @bytenr:    bytenr of the tree block to search
+ * @level:     tree level of the tree block
+ * @owner:     owner of the tree block
+ *
+ * Return >0 for any error found and output error message
+ * Return 0 for no error found
+ */
+static int check_tree_block_ref(struct btrfs_root *root,
+                               struct extent_buffer *eb, u64 bytenr,
+                               int level, u64 owner)
+{
+       struct btrfs_key key;
+       struct btrfs_root *extent_root = root->fs_info->extent_root;
+       struct btrfs_path path;
+       struct btrfs_extent_item *ei;
+       struct btrfs_extent_inline_ref *iref;
+       struct extent_buffer *leaf;
+       unsigned long end;
+       unsigned long ptr;
+       int slot;
+       int skinny_level;
+       int type;
+       u32 nodesize = root->nodesize;
+       u32 item_size;
+       u64 offset;
+       int found_ref = 0;
+       int err = 0;
+       int ret;
+
+       btrfs_init_path(&path);
+       key.objectid = bytenr;
+       if (btrfs_fs_incompat(root->fs_info,
+                             BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA))
+               key.type = BTRFS_METADATA_ITEM_KEY;
+       else
+               key.type = BTRFS_EXTENT_ITEM_KEY;
+       key.offset = (u64)-1;
+
+       /* Search for the backref in extent tree */
+       ret = btrfs_search_slot(NULL, extent_root, &key, &path, 0, 0);
+       if (ret < 0) {
+               err |= BACKREF_MISSING;
+               goto out;
+       }
+       ret = btrfs_previous_extent_item(extent_root, &path, bytenr);
+       if (ret) {
+               err |= BACKREF_MISSING;
+               goto out;
+       }
+
+       leaf = path.nodes[0];
+       slot = path.slots[0];
+       btrfs_item_key_to_cpu(leaf, &key, slot);
+
+       ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
+
+       if (key.type == BTRFS_METADATA_ITEM_KEY) {
+               skinny_level = (int)key.offset;
+               iref = (struct btrfs_extent_inline_ref *)(ei + 1);
+       } else {
+               struct btrfs_tree_block_info *info;
+
+               info = (struct btrfs_tree_block_info *)(ei + 1);
+               skinny_level = btrfs_tree_block_level(leaf, info);
+               iref = (struct btrfs_extent_inline_ref *)(info + 1);
+       }
+
+       if (eb) {
+               u64 header_gen;
+               u64 extent_gen;
+
+               if (!(btrfs_extent_flags(leaf, ei) &
+                     BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
+                       error(
+               "extent[%llu %u] backref type mismatch, missing bit: %llx",
+                               key.objectid, nodesize,
+                               BTRFS_EXTENT_FLAG_TREE_BLOCK);
+                       err = BACKREF_MISMATCH;
+               }
+               header_gen = btrfs_header_generation(eb);
+               extent_gen = btrfs_extent_generation(leaf, ei);
+               if (header_gen != extent_gen) {
+                       error(
+       "extent[%llu %u] backref generation mismatch, wanted: %llu, have: %llu",
+                               key.objectid, nodesize, header_gen,
+                               extent_gen);
+                       err = BACKREF_MISMATCH;
+               }
+               if (level != skinny_level) {
+                       error(
+                       "extent[%llu %u] level mismatch, wanted: %u, have: %u",
+                               key.objectid, nodesize, level, skinny_level);
+                       err = BACKREF_MISMATCH;
+               }
+               if (!is_fstree(owner) && btrfs_extent_refs(leaf, ei) != 1) {
+                       error(
+                       "extent[%llu %u] is referred by other roots than %llu",
+                               key.objectid, nodesize, root->objectid);
+                       err = BACKREF_MISMATCH;
+               }
+       }
+
+       /*
+        * Iterate the extent/metadata item to find the exact backref
+        */
+       item_size = btrfs_item_size_nr(leaf, slot);
+       ptr = (unsigned long)iref;
+       end = (unsigned long)ei + item_size;
+       while (ptr < end) {
+               iref = (struct btrfs_extent_inline_ref *)ptr;
+               type = btrfs_extent_inline_ref_type(leaf, iref);
+               offset = btrfs_extent_inline_ref_offset(leaf, iref);
+
+               if (type == BTRFS_TREE_BLOCK_REF_KEY &&
+                       (offset == root->objectid || offset == owner)) {
+                       found_ref = 1;
+               } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
+                       /* Check if the backref points to valid referencer */
+                       found_ref = !check_tree_block_ref(root, NULL, offset,
+                                                         level + 1, owner);
+               }
+
+               if (found_ref)
+                       break;
+               ptr += btrfs_extent_inline_ref_size(type);
+       }
+
+       /*
+        * Inlined extent item doesn't have what we need, check
+        * TREE_BLOCK_REF_KEY
+        */
+       if (!found_ref) {
+               btrfs_release_path(&path);
+               key.objectid = bytenr;
+               key.type = BTRFS_TREE_BLOCK_REF_KEY;
+               key.offset = root->objectid;
+
+               ret = btrfs_search_slot(NULL, extent_root, &key, &path, 0, 0);
+               if (!ret)
+                       found_ref = 1;
+       }
+       if (!found_ref)
+               err |= BACKREF_MISSING;
+out:
+       btrfs_release_path(&path);
+       if (eb && (err & BACKREF_MISSING))
+               error("extent[%llu %u] backref lost (owner: %llu, level: %u)",
+                       bytenr, nodesize, owner, level);
+       return err;
+}
+
+/*
+ * Check EXTENT_DATA item, mainly for its dbackref in extent tree
+ *
+ * Return >0 any error found and output error message
+ * Return 0 for no error found
+ */
+static int check_extent_data_item(struct btrfs_root *root,
+                                 struct extent_buffer *eb, int slot)
+{
+       struct btrfs_file_extent_item *fi;
+       struct btrfs_path path;
+       struct btrfs_root *extent_root = root->fs_info->extent_root;
+       struct btrfs_key fi_key;
+       struct btrfs_key dbref_key;
+       struct extent_buffer *leaf;
+       struct btrfs_extent_item *ei;
+       struct btrfs_extent_inline_ref *iref;
+       struct btrfs_extent_data_ref *dref;
+       u64 owner;
+       u64 file_extent_gen;
+       u64 disk_bytenr;
+       u64 disk_num_bytes;
+       u64 extent_num_bytes;
+       u64 extent_flags;
+       u64 extent_gen;
+       u32 item_size;
+       unsigned long end;
+       unsigned long ptr;
+       int type;
+       u64 ref_root;
+       int found_dbackref = 0;
+       int err = 0;
+       int ret;
+
+       btrfs_item_key_to_cpu(eb, &fi_key, slot);
+       fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
+       file_extent_gen = btrfs_file_extent_generation(eb, fi);
+
+       /* Nothing to check for hole and inline data extents */
+       if (btrfs_file_extent_type(eb, fi) == BTRFS_FILE_EXTENT_INLINE ||
+           btrfs_file_extent_disk_bytenr(eb, fi) == 0)
+               return 0;
+
+       disk_bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
+       disk_num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
+       extent_num_bytes = btrfs_file_extent_num_bytes(eb, fi);
+
+       /* Check unaligned disk_num_bytes and num_bytes */
+       if (!IS_ALIGNED(disk_num_bytes, root->sectorsize)) {
+               error(
+"file extent [%llu, %llu] has unaligned disk num bytes: %llu, should be aligned to %u",
+                       fi_key.objectid, fi_key.offset, disk_num_bytes,
+                       root->sectorsize);
+               err |= BYTES_UNALIGNED;
+       } else {
+               data_bytes_allocated += disk_num_bytes;
+       }
+       if (!IS_ALIGNED(extent_num_bytes, root->sectorsize)) {
+               error(
+"file extent [%llu, %llu] has unaligned num bytes: %llu, should be aligned to %u",
+                       fi_key.objectid, fi_key.offset, extent_num_bytes,
+                       root->sectorsize);
+               err |= BYTES_UNALIGNED;
+       } else {
+               data_bytes_referenced += extent_num_bytes;
+       }
+       owner = btrfs_header_owner(eb);
+
+       /* Check the extent item of the file extent in extent tree */
+       btrfs_init_path(&path);
+       dbref_key.objectid = btrfs_file_extent_disk_bytenr(eb, fi);
+       dbref_key.type = BTRFS_EXTENT_ITEM_KEY;
+       dbref_key.offset = btrfs_file_extent_disk_num_bytes(eb, fi);
+
+       ret = btrfs_search_slot(NULL, extent_root, &dbref_key, &path, 0, 0);
+       if (ret) {
+               err |= BACKREF_MISSING;
+               goto error;
+       }
+
+       leaf = path.nodes[0];
+       slot = path.slots[0];
+       ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
+
+       extent_flags = btrfs_extent_flags(leaf, ei);
+       extent_gen = btrfs_extent_generation(leaf, ei);
+
+       if (!(extent_flags & BTRFS_EXTENT_FLAG_DATA)) {
+               error(
+                   "extent[%llu %llu] backref type mismatch, wanted bit: %llx",
+                   disk_bytenr, disk_num_bytes,
+                   BTRFS_EXTENT_FLAG_DATA);
+               err |= BACKREF_MISMATCH;
+       }
+
+       if (file_extent_gen < extent_gen) {
+               error(
+"extent[%llu %llu] backref generation mismatch, wanted: <=%llu, have: %llu",
+                       disk_bytenr, disk_num_bytes, file_extent_gen,
+                       extent_gen);
+               err |= BACKREF_MISMATCH;
+       }
+
+       /* Check data backref inside that extent item */
+       item_size = btrfs_item_size_nr(leaf, path.slots[0]);
+       iref = (struct btrfs_extent_inline_ref *)(ei + 1);
+       ptr = (unsigned long)iref;
+       end = (unsigned long)ei + item_size;
+       while (ptr < end) {
+               iref = (struct btrfs_extent_inline_ref *)ptr;
+               type = btrfs_extent_inline_ref_type(leaf, iref);
+               dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+
+               if (type == BTRFS_EXTENT_DATA_REF_KEY) {
+                       ref_root = btrfs_extent_data_ref_root(leaf, dref);
+                       if (ref_root == owner || ref_root == root->objectid)
+                               found_dbackref = 1;
+               } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
+                       found_dbackref = !check_tree_block_ref(root, NULL,
+                               btrfs_extent_inline_ref_offset(leaf, iref),
+                               0, owner);
+               }
+
+               if (found_dbackref)
+                       break;
+               ptr += btrfs_extent_inline_ref_size(type);
+       }
+
+       /* Didn't found inlined data backref, try EXTENT_DATA_REF_KEY */
+       if (!found_dbackref) {
+               btrfs_release_path(&path);
+
+               btrfs_init_path(&path);
+               dbref_key.objectid = btrfs_file_extent_disk_bytenr(eb, fi);
+               dbref_key.type = BTRFS_EXTENT_DATA_REF_KEY;
+               dbref_key.offset = hash_extent_data_ref(root->objectid,
+                               fi_key.objectid, fi_key.offset);
+
+               ret = btrfs_search_slot(NULL, root->fs_info->extent_root,
+                                       &dbref_key, &path, 0, 0);
+               if (!ret)
+                       found_dbackref = 1;
+       }
+
+       if (!found_dbackref)
+               err |= BACKREF_MISSING;
+error:
+       btrfs_release_path(&path);
+       if (err & BACKREF_MISSING) {
+               error("data extent[%llu %llu] backref lost",
+                     disk_bytenr, disk_num_bytes);
+       }
+       return err;
+}
+
+/*
+ * Get real tree block level for the case like shared block
+ * Return >= 0 as tree level
+ * Return <0 for error
+ */
+static int query_tree_block_level(struct btrfs_fs_info *fs_info, u64 bytenr)
+{
+       struct extent_buffer *eb;
+       struct btrfs_path path;
+       struct btrfs_key key;
+       struct btrfs_extent_item *ei;
+       u64 flags;
+       u64 transid;
+       u32 nodesize = btrfs_super_nodesize(fs_info->super_copy);
+       u8 backref_level;
+       u8 header_level;
+       int ret;
+
+       /* Search extent tree for extent generation and level */
+       key.objectid = bytenr;
+       key.type = BTRFS_METADATA_ITEM_KEY;
+       key.offset = (u64)-1;
+
+       btrfs_init_path(&path);
+       ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, &path, 0, 0);
+       if (ret < 0)
+               goto release_out;
+       ret = btrfs_previous_extent_item(fs_info->extent_root, &path, bytenr);
+       if (ret < 0)
+               goto release_out;
+       if (ret > 0) {
+               ret = -ENOENT;
+               goto release_out;
+       }
+
+       btrfs_item_key_to_cpu(path.nodes[0], &key, 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);
+       if (!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
+               ret = -ENOENT;
+               goto release_out;
+       }
+
+       /* Get transid for later read_tree_block() check */
+       transid = btrfs_extent_generation(path.nodes[0], ei);
+
+       /* Get backref level as one source */
+       if (key.type == BTRFS_METADATA_ITEM_KEY) {
+               backref_level = key.offset;
+       } else {
+               struct btrfs_tree_block_info *info;
+
+               info = (struct btrfs_tree_block_info *)(ei + 1);
+               backref_level = btrfs_tree_block_level(path.nodes[0], info);
+       }
+       btrfs_release_path(&path);
+
+       /* Get level from tree block as an alternative source */
+       eb = read_tree_block_fs_info(fs_info, bytenr, nodesize, transid);
+       if (!extent_buffer_uptodate(eb)) {
+               free_extent_buffer(eb);
+               return -EIO;
+       }
+       header_level = btrfs_header_level(eb);
+       free_extent_buffer(eb);
+
+       if (header_level != backref_level)
+               return -EIO;
+       return header_level;
+
+release_out:
+       btrfs_release_path(&path);
+       return ret;
+}
+
+/*
+ * Check if a tree block backref is valid (points to a valid tree block)
+ * if level == -1, level will be resolved
+ * Return >0 for any error found and print error message
+ */
+static int check_tree_block_backref(struct btrfs_fs_info *fs_info, u64 root_id,
+                                   u64 bytenr, int level)
 {
-       struct rb_root dev_cache;
-       struct cache_tree chunk_cache;
-       struct block_group_tree block_group_cache;
-       struct device_extent_tree dev_extent_cache;
-       struct cache_tree extent_cache;
-       struct cache_tree seen;
-       struct cache_tree pending;
-       struct cache_tree reada;
-       struct cache_tree nodes;
-       struct extent_io_tree excluded_extents;
-       struct cache_tree corrupt_blocks;
-       struct btrfs_path path;
+       struct btrfs_root *root;
        struct btrfs_key key;
-       struct btrfs_key found_key;
-       int ret, err = 0;
-       struct block_info *bits;
-       int bits_nr;
-       struct extent_buffer *leaf;
-       int slot;
-       struct btrfs_root_item ri;
-       struct list_head dropping_trees;
-       struct list_head normal_trees;
-       struct btrfs_root *root1;
-       u64 objectid;
-       u32 level_size;
-       u8 level;
+       struct btrfs_path path;
+       struct extent_buffer *eb;
+       struct extent_buffer *node;
+       u32 nodesize = btrfs_super_nodesize(fs_info->super_copy);
+       int err = 0;
+       int ret;
 
-       dev_cache = RB_ROOT;
-       cache_tree_init(&chunk_cache);
-       block_group_tree_init(&block_group_cache);
-       device_extent_tree_init(&dev_extent_cache);
+       /* Query level for level == -1 special case */
+       if (level == -1)
+               level = query_tree_block_level(fs_info, bytenr);
+       if (level < 0) {
+               err |= REFERENCER_MISSING;
+               goto out;
+       }
 
-       cache_tree_init(&extent_cache);
-       cache_tree_init(&seen);
-       cache_tree_init(&pending);
-       cache_tree_init(&nodes);
-       cache_tree_init(&reada);
-       cache_tree_init(&corrupt_blocks);
-       extent_io_tree_init(&excluded_extents);
-       INIT_LIST_HEAD(&dropping_trees);
-       INIT_LIST_HEAD(&normal_trees);
+       key.objectid = root_id;
+       key.type = BTRFS_ROOT_ITEM_KEY;
+       key.offset = (u64)-1;
 
-       if (repair) {
-               root->fs_info->excluded_extents = &excluded_extents;
-               root->fs_info->fsck_extent_cache = &extent_cache;
-               root->fs_info->free_extent_hook = free_extent_hook;
-               root->fs_info->corrupt_blocks = &corrupt_blocks;
+       root = btrfs_read_fs_root(fs_info, &key);
+       if (IS_ERR(root)) {
+               err |= REFERENCER_MISSING;
+               goto out;
        }
 
-       bits_nr = 1024;
-       bits = malloc(bits_nr * sizeof(struct block_info));
-       if (!bits) {
-               perror("malloc");
-               exit(1);
+       /* Read out the tree block to get item/node key */
+       eb = read_tree_block(root, bytenr, root->nodesize, 0);
+       if (!extent_buffer_uptodate(eb)) {
+               err |= REFERENCER_MISSING;
+               free_extent_buffer(eb);
+               goto out;
        }
 
-again:
-       root1 = root->fs_info->tree_root;
-       level = btrfs_header_level(root1->node);
-       ret = add_root_item_to_list(&normal_trees, root1->root_key.objectid,
-                                   root1->node->start, 0, level, 0,
-                                   btrfs_level_size(root1, level), NULL);
-       if (ret < 0)
-               goto out;
-       root1 = root->fs_info->chunk_root;
-       level = btrfs_header_level(root1->node);
-       ret = add_root_item_to_list(&normal_trees, root1->root_key.objectid,
-                                   root1->node->start, 0, level, 0,
-                                   btrfs_level_size(root1, level), NULL);
-       if (ret < 0)
-               goto out;
-       btrfs_init_path(&path);
-       key.offset = 0;
-       key.objectid = 0;
-       btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
-       ret = btrfs_search_slot(NULL, root->fs_info->tree_root,
-                                       &key, &path, 0, 0);
-       if (ret < 0)
+       /* Empty tree, no need to check key */
+       if (!btrfs_header_nritems(eb) && !level) {
+               free_extent_buffer(eb);
                goto out;
-       while(1) {
-               leaf = path.nodes[0];
-               slot = path.slots[0];
-               if (slot >= btrfs_header_nritems(path.nodes[0])) {
-                       ret = btrfs_next_leaf(root, &path);
-                       if (ret != 0)
-                               break;
-                       leaf = path.nodes[0];
-                       slot = path.slots[0];
-               }
-               btrfs_item_key_to_cpu(leaf, &found_key, path.slots[0]);
-               if (btrfs_key_type(&found_key) == BTRFS_ROOT_ITEM_KEY) {
-                       unsigned long offset;
-                       u64 last_snapshot;
+       }
 
-                       offset = btrfs_item_ptr_offset(leaf, path.slots[0]);
-                       read_extent_buffer(leaf, &ri, offset, sizeof(ri));
-                       last_snapshot = btrfs_root_last_snapshot(&ri);
-                       if (btrfs_disk_key_objectid(&ri.drop_progress) == 0) {
-                               level = btrfs_root_level(&ri);
-                               level_size = btrfs_level_size(root, level);
-                               ret = add_root_item_to_list(&normal_trees,
-                                               found_key.objectid,
-                                               btrfs_root_bytenr(&ri),
-                                               last_snapshot, level,
-                                               0, level_size, NULL);
-                               if (ret < 0)
-                                       goto out;
-                       } else {
-                               level = btrfs_root_level(&ri);
-                               level_size = btrfs_level_size(root, level);
-                               objectid = found_key.objectid;
-                               btrfs_disk_key_to_cpu(&found_key,
-                                                     &ri.drop_progress);
-                               ret = add_root_item_to_list(&dropping_trees,
-                                               objectid,
-                                               btrfs_root_bytenr(&ri),
-                                               last_snapshot, level,
-                                               ri.drop_level,
-                                               level_size, &found_key);
-                               if (ret < 0)
-                                       goto out;
-                       }
-               }
-               path.slots[0]++;
+       if (level)
+               btrfs_node_key_to_cpu(eb, &key, 0);
+       else
+               btrfs_item_key_to_cpu(eb, &key, 0);
+
+       free_extent_buffer(eb);
+
+       btrfs_init_path(&path);
+       /* Search with the first key, to ensure we can reach it */
+       ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+       if (ret) {
+               err |= REFERENCER_MISSING;
+               goto release_out;
        }
-       btrfs_release_path(&path);
 
-       /*
-        * check_block can return -EAGAIN if it fixes something, please keep
-        * this in mind when dealing with return values from these functions, if
-        * we get -EAGAIN we want to fall through and restart the loop.
-        */
-       ret = deal_root_from_list(&normal_trees, root, bits, bits_nr, &pending,
-                                 &seen, &reada, &nodes, &extent_cache,
-                                 &chunk_cache, &dev_cache, &block_group_cache,
-                                 &dev_extent_cache);
-       if (ret < 0) {
-               if (ret == -EAGAIN)
-                       goto loop;
-               goto out;
+       node = path.nodes[level];
+       if (btrfs_header_bytenr(node) != bytenr) {
+               error(
+       "extent [%llu %d] referencer bytenr mismatch, wanted: %llu, have: %llu",
+                       bytenr, nodesize, bytenr,
+                       btrfs_header_bytenr(node));
+               err |= REFERENCER_MISMATCH;
        }
-       ret = deal_root_from_list(&dropping_trees, root, bits, bits_nr,
-                                 &pending, &seen, &reada, &nodes,
-                                 &extent_cache, &chunk_cache, &dev_cache,
-                                 &block_group_cache, &dev_extent_cache);
-       if (ret < 0) {
-               if (ret == -EAGAIN)
-                       goto loop;
-               goto out;
+       if (btrfs_header_level(node) != level) {
+               error(
+       "extent [%llu %d] referencer level mismatch, wanted: %d, have: %d",
+                       bytenr, nodesize, level,
+                       btrfs_header_level(node));
+               err |= REFERENCER_MISMATCH;
        }
 
-       err = check_chunks(&chunk_cache, &block_group_cache,
-                          &dev_extent_cache, NULL, NULL, NULL, 0);
-       if (err) {
-               if (err == -EAGAIN)
-                       goto loop;
-               if (!ret)
-                       ret = err;
+release_out:
+       btrfs_release_path(&path);
+out:
+       if (err & REFERENCER_MISSING) {
+               if (level < 0)
+                       error("extent [%llu %d] lost referencer (owner: %llu)",
+                               bytenr, nodesize, root_id);
+               else
+                       error(
+               "extent [%llu %d] lost referencer (owner: %llu, level: %u)",
+                               bytenr, nodesize, root_id, level);
        }
 
-       ret = check_extent_refs(root, &extent_cache);
-       if (ret < 0) {
-               if (ret == -EAGAIN)
-                       goto loop;
+       return err;
+}
+
+/*
+ * Check referencer for shared block backref
+ * If level == -1, this function will resolve the level.
+ */
+static int check_shared_block_backref(struct btrfs_fs_info *fs_info,
+                                    u64 parent, u64 bytenr, int level)
+{
+       struct extent_buffer *eb;
+       u32 nodesize = btrfs_super_nodesize(fs_info->super_copy);
+       u32 nr;
+       int found_parent = 0;
+       int i;
+
+       eb = read_tree_block_fs_info(fs_info, parent, nodesize, 0);
+       if (!extent_buffer_uptodate(eb))
                goto out;
-       }
 
-       err = check_devices(&dev_cache, &dev_extent_cache);
-       if (err && !ret)
-               ret = err;
+       if (level == -1)
+               level = query_tree_block_level(fs_info, bytenr);
+       if (level < 0)
+               goto out;
+
+       if (level + 1 != btrfs_header_level(eb))
+               goto out;
 
+       nr = btrfs_header_nritems(eb);
+       for (i = 0; i < nr; i++) {
+               if (bytenr == btrfs_node_blockptr(eb, i)) {
+                       found_parent = 1;
+                       break;
+               }
+       }
 out:
-       if (repair) {
-               free_corrupt_blocks_tree(root->fs_info->corrupt_blocks);
-               extent_io_tree_cleanup(&excluded_extents);
-               root->fs_info->fsck_extent_cache = NULL;
-               root->fs_info->free_extent_hook = NULL;
-               root->fs_info->corrupt_blocks = NULL;
-               root->fs_info->excluded_extents = NULL;
+       free_extent_buffer(eb);
+       if (!found_parent) {
+               error(
+       "shared extent[%llu %u] lost its parent (parent: %llu, level: %u)",
+                       bytenr, nodesize, parent, level);
+               return REFERENCER_MISSING;
        }
-       free(bits);
-       free_chunk_cache_tree(&chunk_cache);
-       free_device_cache_tree(&dev_cache);
-       free_block_group_tree(&block_group_cache);
-       free_device_extent_tree(&dev_extent_cache);
-       free_extent_cache_tree(&seen);
-       free_extent_cache_tree(&pending);
-       free_extent_cache_tree(&reada);
-       free_extent_cache_tree(&nodes);
-       return ret;
-loop:
-       free_corrupt_blocks_tree(root->fs_info->corrupt_blocks);
-       free_extent_cache_tree(&seen);
-       free_extent_cache_tree(&pending);
-       free_extent_cache_tree(&reada);
-       free_extent_cache_tree(&nodes);
-       free_chunk_cache_tree(&chunk_cache);
-       free_block_group_tree(&block_group_cache);
-       free_device_cache_tree(&dev_cache);
-       free_device_extent_tree(&dev_extent_cache);
-       free_extent_record_cache(root->fs_info, &extent_cache);
-       free_root_item_list(&normal_trees);
-       free_root_item_list(&dropping_trees);
-       extent_io_tree_cleanup(&excluded_extents);
-       goto again;
+       return 0;
 }
 
 static int btrfs_fsck_reinit_root(struct btrfs_trans_handle *trans,
@@ -8096,7 +9094,7 @@ static int btrfs_fsck_reinit_root(struct btrfs_trans_handle *trans,
                goto init;
        }
        c = btrfs_alloc_free_block(trans, root,
-                                  btrfs_level_size(root, 0),
+                                  root->nodesize,
                                   root->root_key.objectid,
                                   &disk_key, level, 0, 0);
        if (IS_ERR(c)) {
@@ -8153,7 +9151,7 @@ static int pin_down_tree_blocks(struct btrfs_fs_info *fs_info,
        struct btrfs_root_item *ri;
        struct btrfs_key key;
        u64 bytenr;
-       u32 leafsize;
+       u32 nodesize;
        int level = btrfs_header_level(eb);
        int nritems;
        int ret;
@@ -8170,7 +9168,7 @@ static int pin_down_tree_blocks(struct btrfs_fs_info *fs_info,
 
        btrfs_pin_extent(fs_info, eb->start, eb->len);
 
-       leafsize = btrfs_super_leafsize(fs_info->super_copy);
+       nodesize = btrfs_super_nodesize(fs_info->super_copy);
        nritems = btrfs_header_nritems(eb);
        for (i = 0; i < nritems; i++) {
                if (level == 0) {
@@ -8192,7 +9190,7 @@ static int pin_down_tree_blocks(struct btrfs_fs_info *fs_info,
                         * just pass in extent_root.
                         */
                        tmp = read_tree_block(fs_info->extent_root, bytenr,
-                                             leafsize, 0);
+                                             nodesize, 0);
                        if (!extent_buffer_uptodate(tmp)) {
                                fprintf(stderr, "Error reading root block\n");
                                return -EIO;
@@ -8206,12 +9204,12 @@ static int pin_down_tree_blocks(struct btrfs_fs_info *fs_info,
 
                        /* If we aren't the tree root don't read the block */
                        if (level == 1 && !tree_root) {
-                               btrfs_pin_extent(fs_info, bytenr, leafsize);
+                               btrfs_pin_extent(fs_info, bytenr, nodesize);
                                continue;
                        }
 
                        tmp = read_tree_block(fs_info->extent_root, bytenr,
-                                             leafsize, 0);
+                                             nodesize, 0);
                        if (!extent_buffer_uptodate(tmp)) {
                                fprintf(stderr, "Error reading tree block\n");
                                return -EIO;
@@ -8501,7 +9499,7 @@ static int reinit_extent_tree(struct btrfs_trans_handle *trans,
 
        ret = reset_balance(trans, fs_info);
        if (ret)
-               fprintf(stderr, "error reseting the pending balance\n");
+               fprintf(stderr, "error resetting the pending balance\n");
 
        return ret;
 }
@@ -8849,18 +9847,6 @@ static int fill_csum_tree(struct btrfs_trans_handle *trans,
                return fill_csum_tree_from_extent(trans, csum_root);
 }
 
-struct root_item_info {
-       /* level of the root */
-       u8 level;
-       /* number of nodes at this level, must be 1 for a root */
-       int node_count;
-       u64 bytenr;
-       u64 gen;
-       struct cache_extent cache_extent;
-};
-
-static struct cache_tree *roots_info_cache = NULL;
-
 static void free_roots_info_cache(void)
 {
        if (!roots_info_cache)
@@ -8950,11 +9936,11 @@ static int build_roots_info_cache(struct btrfs_fs_info *info)
                        iref = (struct btrfs_extent_inline_ref *)(ei + 1);
                        level = found_key.offset;
                } else {
-                       struct btrfs_tree_block_info *info;
+                       struct btrfs_tree_block_info *binfo;
 
-                       info = (struct btrfs_tree_block_info *)(ei + 1);
-                       iref = (struct btrfs_extent_inline_ref *)(info + 1);
-                       level = btrfs_tree_block_level(leaf, info);
+                       binfo = (struct btrfs_tree_block_info *)(ei + 1);
+                       iref = (struct btrfs_extent_inline_ref *)(binfo + 1);
+                       level = btrfs_tree_block_level(leaf, binfo);
                }
 
                /*
@@ -9184,8 +10170,7 @@ next:
        ret = 0;
 out:
        free_roots_info_cache();
-       if (path)
-               btrfs_free_path(path);
+       btrfs_free_path(path);
        if (trans)
                btrfs_commit_transaction(trans, info->tree_root);
        if (ret < 0)
@@ -9196,17 +10181,25 @@ out:
 
 const char * const cmd_check_usage[] = {
        "btrfs check [options] <device>",
-       "Check an unmounted btrfs filesystem.",
+       "Check structural integrity of a filesystem (unmounted).",
+       "Check structural integrity of an unmounted filesystem. Verify internal",
+       "trees' consistency and item connectivity. In the repair mode try to",
+       "fix the problems found.",
+       "WARNING: the repair mode is considered dangerous",
        "",
        "-s|--super <superblock>     use this superblock copy",
-       "-b|--backup                 use the backup root copy",
+       "-b|--backup                 use the first valid backup root copy",
        "--repair                    try to repair the filesystem",
+       "--readonly                  run in read-only mode (default)",
        "--init-csum-tree            create a new CRC tree",
        "--init-extent-tree          create a new extent tree",
-       "--check-data-csum           verify checkums of data blocks",
-       "--qgroup-report             print a report on qgroup consistency",
-       "--subvol-extents <subvolid> print subvolume extents and sharing state",
-       "--tree-root <bytenr>        use the given bytenr for the tree root",
+       "--check-data-csum           verify checksums of data blocks",
+       "-Q|--qgroup-report           print a report on qgroup consistency",
+       "-E|--subvol-extents <subvolid>",
+       "                            print subvolume extents and sharing state",
+       "-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",
        NULL
 };
 
@@ -9218,33 +10211,42 @@ int cmd_check(int argc, char **argv)
        u64 bytenr = 0;
        u64 subvolid = 0;
        u64 tree_root_bytenr = 0;
+       u64 chunk_root_bytenr = 0;
        char uuidbuf[BTRFS_UUID_UNPARSED_SIZE];
        int ret;
        u64 num;
        int init_csum_tree = 0;
        int readonly = 0;
        int qgroup_report = 0;
+       int qgroups_repaired = 0;
        enum btrfs_open_ctree_flags ctree_flags = OPEN_CTREE_EXCLUSIVE;
 
        while(1) {
                int c;
-               enum { OPT_REPAIR = 257, OPT_INIT_CSUM, OPT_INIT_EXTENT,
-                       OPT_CHECK_CSUM, OPT_READONLY };
+               enum { GETOPT_VAL_REPAIR = 257, GETOPT_VAL_INIT_CSUM,
+                       GETOPT_VAL_INIT_EXTENT, GETOPT_VAL_CHECK_CSUM,
+                       GETOPT_VAL_READONLY, GETOPT_VAL_CHUNK_TREE };
                static const struct option long_options[] = {
                        { "super", required_argument, NULL, 's' },
-                       { "repair", no_argument, NULL, OPT_REPAIR },
-                       { "readonly", no_argument, NULL, OPT_READONLY },
-                       { "init-csum-tree", no_argument, NULL, OPT_INIT_CSUM },
-                       { "init-extent-tree", no_argument, NULL, OPT_INIT_EXTENT },
-                       { "check-data-csum", no_argument, NULL, OPT_CHECK_CSUM },
+                       { "repair", no_argument, NULL, GETOPT_VAL_REPAIR },
+                       { "readonly", no_argument, NULL, GETOPT_VAL_READONLY },
+                       { "init-csum-tree", no_argument, NULL,
+                               GETOPT_VAL_INIT_CSUM },
+                       { "init-extent-tree", no_argument, NULL,
+                               GETOPT_VAL_INIT_EXTENT },
+                       { "check-data-csum", no_argument, NULL,
+                               GETOPT_VAL_CHECK_CSUM },
                        { "backup", no_argument, NULL, 'b' },
                        { "subvol-extents", required_argument, NULL, 'E' },
                        { "qgroup-report", no_argument, NULL, 'Q' },
                        { "tree-root", required_argument, NULL, 'r' },
+                       { "chunk-root", required_argument, NULL,
+                               GETOPT_VAL_CHUNK_TREE },
+                       { "progress", no_argument, NULL, 'p' },
                        { NULL, 0, NULL, 0}
                };
 
-               c = getopt_long(argc, argv, "as:br:", long_options, NULL);
+               c = getopt_long(argc, argv, "as:br:p", long_options, NULL);
                if (c < 0)
                        break;
                switch(c) {
@@ -9273,39 +10275,49 @@ int cmd_check(int argc, char **argv)
                        case 'r':
                                tree_root_bytenr = arg_strtou64(optarg);
                                break;
+                       case GETOPT_VAL_CHUNK_TREE:
+                               chunk_root_bytenr = arg_strtou64(optarg);
+                               break;
+                       case 'p':
+                               ctx.progress_enabled = true;
+                               break;
                        case '?':
                        case 'h':
                                usage(cmd_check_usage);
-                       case OPT_REPAIR:
+                       case GETOPT_VAL_REPAIR:
                                printf("enabling repair mode\n");
                                repair = 1;
                                ctree_flags |= OPEN_CTREE_WRITES;
                                break;
-                       case OPT_READONLY:
+                       case GETOPT_VAL_READONLY:
                                readonly = 1;
                                break;
-                       case OPT_INIT_CSUM:
+                       case GETOPT_VAL_INIT_CSUM:
                                printf("Creating a new CRC tree\n");
                                init_csum_tree = 1;
                                repair = 1;
                                ctree_flags |= OPEN_CTREE_WRITES;
                                break;
-                       case OPT_INIT_EXTENT:
+                       case GETOPT_VAL_INIT_EXTENT:
                                init_extent_tree = 1;
                                ctree_flags |= (OPEN_CTREE_WRITES |
                                                OPEN_CTREE_NO_BLOCK_GROUPS);
                                repair = 1;
                                break;
-                       case OPT_CHECK_CSUM:
+                       case GETOPT_VAL_CHECK_CSUM:
                                check_data_csum = 1;
                                break;
                }
        }
-       argc = argc - optind;
 
-       if (check_argc_exact(argc, 1))
+       if (check_argc_exact(argc - optind, 1))
                usage(cmd_check_usage);
 
+       if (ctx.progress_enabled) {
+               ctx.tp = TASK_NOTHING;
+               ctx.info = task_init(print_status_check, print_status_return, &ctx);
+       }
+
        /* This check is the only reason for --readonly to exist */
        if (readonly && repair) {
                fprintf(stderr, "Repair options are not compatible with --readonly\n");
@@ -9329,13 +10341,14 @@ int cmd_check(int argc, char **argv)
                ctree_flags |= OPEN_CTREE_PARTIAL;
 
        info = open_ctree_fs_info(argv[optind], bytenr, tree_root_bytenr,
-                                 ctree_flags);
+                                 chunk_root_bytenr, ctree_flags);
        if (!info) {
                fprintf(stderr, "Couldn't open file system\n");
                ret = -EIO;
                goto err_out;
        }
 
+       global_info = info;
        root = info->fs_root;
 
        /*
@@ -9361,7 +10374,7 @@ int cmd_check(int argc, char **argv)
                       uuidbuf);
                ret = qgroup_verify_all(info);
                if (ret == 0)
-                       print_qgroup_report(1);
+                       report_qgroups(1);
                goto close_out;
        }
        if (subvolid) {
@@ -9432,7 +10445,8 @@ int cmd_check(int argc, char **argv)
                goto close_out;
        }
 
-       fprintf(stderr, "checking extents\n");
+       if (!ctx.progress_enabled)
+               fprintf(stderr, "checking extents\n");
        ret = check_chunks_and_extents(root);
        if (ret)
                fprintf(stderr, "Errors found in extent allocation tree or chunk allocation\n");
@@ -9453,7 +10467,12 @@ int cmd_check(int argc, char **argv)
                goto close_out;
        }
 
-       fprintf(stderr, "checking free space cache\n");
+       if (!ctx.progress_enabled) {
+               if (btrfs_fs_compat_ro(info, BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE))
+                       fprintf(stderr, "checking free space tree\n");
+               else
+                       fprintf(stderr, "checking free space cache\n");
+       }
        ret = check_space_cache(root);
        if (ret)
                goto out;
@@ -9466,7 +10485,8 @@ int cmd_check(int argc, char **argv)
         */
        no_holes = btrfs_fs_incompat(root->fs_info,
                                     BTRFS_FEATURE_INCOMPAT_NO_HOLES);
-       fprintf(stderr, "checking fs roots\n");
+       if (!ctx.progress_enabled)
+               fprintf(stderr, "checking fs roots\n");
        ret = check_fs_roots(root, &root_cache);
        if (ret)
                goto out;
@@ -9508,6 +10528,10 @@ int cmd_check(int argc, char **argv)
                err = qgroup_verify_all(info);
                if (err)
                        goto out;
+               report_qgroups(0);
+               err = repair_qgroups(info, &qgroups_repaired);
+               if (err)
+                       goto out;
        }
 
        if (!list_empty(&root->fs_info->recow_ebs)) {
@@ -9515,7 +10539,10 @@ int cmd_check(int argc, char **argv)
                ret = 1;
        }
 out:
-       print_qgroup_report(0);
+       /* Don't override original ret */
+       if (!ret && qgroups_repaired)
+               ret = qgroups_repaired;
+
        if (found_old_backref) { /*
                 * there was a disk format change when mixed
                 * backref was in testing tree. The old format
@@ -9541,11 +10568,14 @@ out:
        printf("file data blocks allocated: %llu\n referenced %llu\n",
                (unsigned long long)data_bytes_allocated,
                (unsigned long long)data_bytes_referenced);
-       printf("%s\n", PACKAGE_STRING);
 
+       free_qgroup_counts();
        free_root_recs_tree(&root_cache);
 close_out:
        close_ctree(root);
 err_out:
+       if (ctx.progress_enabled)
+               task_deinit(ctx.info);
+
        return ret;
 }