7 files changed, 710 insertions, 79 deletions

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 7084431b7c9c..dc963121d1db 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1109,6 +1109,74 @@ static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
                                 found_key);
 }
 
+int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
+                          u64 start_off, struct btrfs_path *path,
+                          struct btrfs_inode_extref **ret_extref,
+                          u64 *found_off)
+{
+        int ret, slot;
+        struct btrfs_key key;
+        struct btrfs_key found_key;
+        struct btrfs_inode_extref *extref;
+        struct extent_buffer *leaf;
+        unsigned long ptr;
+
+        key.objectid = inode_objectid;
+        btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
+        key.offset = start_off;
+
+        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+        if (ret < 0)
+                return ret;
+
+        while (1) {
+                leaf = path->nodes[0];
+                slot = path->slots[0];
+                if (slot >= btrfs_header_nritems(leaf)) {
+                        /*
+                         * If the item at offset is not found,
+                         * btrfs_search_slot will point us to the slot
+                         * where it should be inserted. In our case
+                         * that will be the slot directly before the
+                         * next INODE_REF_KEY_V2 item. In the case
+                         * that we're pointing to the last slot in a
+                         * leaf, we must move one leaf over.
+                         */
+                        ret = btrfs_next_leaf(root, path);
+                        if (ret) {
+                                if (ret >= 1)
+                                        ret = -ENOENT;
+                                break;
+                        }
+                        continue;
+                }
+
+                btrfs_item_key_to_cpu(leaf, &found_key, slot);
+
+                /*
+                 * Check that we're still looking at an extended ref key for
+                 * this particular objectid. If we have different
+                 * objectid or type then there are no more to be found
+                 * in the tree and we can exit.
+                 */
+                ret = -ENOENT;
+                if (found_key.objectid != inode_objectid)
+                        break;
+                if (btrfs_key_type(&found_key) != BTRFS_INODE_EXTREF_KEY)
+                        break;
+
+                ret = 0;
+                ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
+                extref = (struct btrfs_inode_extref *)ptr;
+                *ret_extref = extref;
+                if (found_off)
+                        *found_off = found_key.offset;
+                break;
+        }
+
+        return ret;
+}
+
 /*
  * this iterates to turn a btrfs_inode_ref into a full filesystem path. elements
  * of the path are separated by '/' and the path is guaranteed to be
diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index 4fda5d8029a7..0b920c113952 100644
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -70,4 +70,9 @@ struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
                                         struct btrfs_path *path);
 void free_ipath(struct inode_fs_paths *ipath);
 
+int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
+                          u64 start_off, struct btrfs_path *path,
+                          struct btrfs_inode_extref **ret_extref,
+                          u64 *found_off);
+
 #endif
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 399521ab61da..50dcd0fbae11 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -154,6 +154,13 @@ struct btrfs_ordered_sum;
  */
 #define BTRFS_NAME_LEN 255
 
+/*
+ * Theoretical limit is larger, but we keep this down to a sane
+ * value. That should limit greatly the possibility of collisions on
+ * inode ref items.
+ */
+#define BTRFS_LINK_MAX 65535U
+
 /* 32 bytes in various csum fields */
 #define BTRFS_CSUM_SIZE 32
 
@@ -489,6 +496,8 @@ struct btrfs_super_block {
  */
 #define BTRFS_FEATURE_INCOMPAT_BIG_METADATA     (1ULL << 5)
 
+#define BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF    (1ULL << 6)
+
 #define BTRFS_FEATURE_COMPAT_SUPP               0ULL
 #define BTRFS_FEATURE_COMPAT_RO_SUPP            0ULL
 #define BTRFS_FEATURE_INCOMPAT_SUPP                     \
@@ -496,7 +505,8 @@ struct btrfs_super_block {
          BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |        \
          BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |          \
          BTRFS_FEATURE_INCOMPAT_BIG_METADATA |          \
-         BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO)
+         BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO |          \
+         BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
 
 /*
  * A leaf is full of items. offset and size tell us where to find
@@ -643,6 +653,14 @@ struct btrfs_inode_ref {
         /* name goes here */
 } __attribute__ ((__packed__));
 
+struct btrfs_inode_extref {
+        __le64 parent_objectid;
+        __le64 index;
+        __le16 name_len;
+        __u8   name[0];
+        /* name goes here */
+} __attribute__ ((__packed__));
+
 struct btrfs_timespec {
         __le64 sec;
         __le32 nsec;
@@ -1601,6 +1619,7 @@ struct btrfs_ioctl_defrag_range_args {
  */
 #define BTRFS_INODE_ITEM_KEY            1
 #define BTRFS_INODE_REF_KEY             12
+#define BTRFS_INODE_EXTREF_KEY          13
 #define BTRFS_XATTR_ITEM_KEY            24
 #define BTRFS_ORPHAN_ITEM_KEY           48
 /* reserve 2-15 close to the inode for later flexibility */
@@ -1987,6 +2006,13 @@ BTRFS_SETGET_STACK_FUNCS(block_group_flags,
 BTRFS_SETGET_FUNCS(inode_ref_name_len, struct btrfs_inode_ref, name_len, 16);
 BTRFS_SETGET_FUNCS(inode_ref_index, struct btrfs_inode_ref, index, 64);
 
+/* struct btrfs_inode_extref */
+BTRFS_SETGET_FUNCS(inode_extref_parent, struct btrfs_inode_extref,
+                   parent_objectid, 64);
+BTRFS_SETGET_FUNCS(inode_extref_name_len, struct btrfs_inode_extref,
+                   name_len, 16);
+BTRFS_SETGET_FUNCS(inode_extref_index, struct btrfs_inode_extref, index, 64);
+
 /* struct btrfs_inode_item */
 BTRFS_SETGET_FUNCS(inode_generation, struct btrfs_inode_item, generation, 64);
 BTRFS_SETGET_FUNCS(inode_sequence, struct btrfs_inode_item, sequence, 64);
@@ -3184,12 +3210,12 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root,
                            const char *name, int name_len,
                            u64 inode_objectid, u64 ref_objectid, u64 *index);
-struct btrfs_inode_ref *
-btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
-                        struct btrfs_root *root,
-                        struct btrfs_path *path,
-                        const char *name, int name_len,
-                        u64 inode_objectid, u64 ref_objectid, int mod);
+int btrfs_get_inode_ref_index(struct btrfs_trans_handle *trans,
+                              struct btrfs_root *root,
+                              struct btrfs_path *path,
+                              const char *name, int name_len,
+                              u64 inode_objectid, u64 ref_objectid, int mod,
+                              u64 *ret_index);
 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
                              struct btrfs_root *root,
                              struct btrfs_path *path, u64 objectid);
@@ -3197,6 +3223,19 @@ int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
                        *root, struct btrfs_path *path,
                        struct btrfs_key *location, int mod);
 
+struct btrfs_inode_extref *
+btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
+                          struct btrfs_root *root,
+                          struct btrfs_path *path,
+                          const char *name, int name_len,
+                          u64 inode_objectid, u64 ref_objectid, int ins_len,
+                          int cow);
+
+int btrfs_find_name_in_ext_backref(struct btrfs_path *path,
+                                   u64 ref_objectid, const char *name,
+                                   int name_len,
+                                   struct btrfs_inode_extref **extref_ret);
+
 /* file-item.c */
 int btrfs_del_csums(struct btrfs_trans_handle *trans,
                     struct btrfs_root *root, u64 bytenr, u64 len);
diff --git a/fs/btrfs/hash.h b/fs/btrfs/hash.h
index db2ff9773b99..1d982812ab67 100644
--- a/fs/btrfs/hash.h
+++ b/fs/btrfs/hash.h
@@ -24,4 +24,14 @@ static inline u64 btrfs_name_hash(const char *name, int len)
 {
         return crc32c((u32)~1, name, len);
 }
+
+/*
+ * Figure the key offset of an extended inode ref
+ */
+static inline u64 btrfs_extref_hash(u64 parent_objectid, const char *name,
+                                    int len)
+{
+        return (u64) crc32c(parent_objectid, name, len);
+}
+
 #endif
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index a13cf1a96c73..48b8fda93132 100644
--- a/fs/btrfs/inode-item.c
+++ b/fs/btrfs/inode-item.c
@@ -18,6 +18,7 @@
 
 #include "ctree.h"
 #include "disk-io.h"
+#include "hash.h"
 #include "transaction.h"
 #include "print-tree.h"
 
@@ -50,18 +51,57 @@ static int find_name_in_backref(struct btrfs_path *path, const char *name,
         return 0;
 }
 
-struct btrfs_inode_ref *
+int btrfs_find_name_in_ext_backref(struct btrfs_path *path, u64 ref_objectid,
+                                   const char *name, int name_len,
+                                   struct btrfs_inode_extref **extref_ret)
+{
+        struct extent_buffer *leaf;
+        struct btrfs_inode_extref *extref;
+        unsigned long ptr;
+        unsigned long name_ptr;
+        u32 item_size;
+        u32 cur_offset = 0;
+        int ref_name_len;
+
+        leaf = path->nodes[0];
+        item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+        ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
+
+        /*
+         * Search all extended backrefs in this item. We're only
+         * looking through any collisions so most of the time this is
+         * just going to compare against one buffer. If all is well,
+         * we'll return success and the inode ref object.
+         */
+        while (cur_offset < item_size) {
+                extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
+                name_ptr = (unsigned long)(&extref->name);
+                ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
+
+                if (ref_name_len == name_len &&
+                    btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
+                    (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)) {
+                        if (extref_ret)
+                                *extref_ret = extref;
+                        return 1;
+                }
+
+                cur_offset += ref_name_len + sizeof(*extref);
+        }
+        return 0;
+}
+
+static struct btrfs_inode_ref *
 btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
-                        struct btrfs_root *root,
-                        struct btrfs_path *path,
-                        const char *name, int name_len,
-                        u64 inode_objectid, u64 ref_objectid, int mod)
+                       struct btrfs_root *root,
+                       struct btrfs_path *path,
+                       const char *name, int name_len,
+                       u64 inode_objectid, u64 ref_objectid, int ins_len,
+                       int cow)
 {
+        int ret;
         struct btrfs_key key;
         struct btrfs_inode_ref *ref;
-        int ins_len = mod < 0 ? -1 : 0;
-        int cow = mod != 0;
-        int ret;
 
         key.objectid = inode_objectid;
         key.type = BTRFS_INODE_REF_KEY;
@@ -77,13 +117,150 @@ btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
         return ref;
 }
 
-int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
+/* Returns NULL if no extref found */
+struct btrfs_inode_extref *
+btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
+                          struct btrfs_root *root,
+                          struct btrfs_path *path,
+                          const char *name, int name_len,
+                          u64 inode_objectid, u64 ref_objectid, int ins_len,
+                          int cow)
+{
+        int ret;
+        struct btrfs_key key;
+        struct btrfs_inode_extref *extref;
+
+        key.objectid = inode_objectid;
+        key.type = BTRFS_INODE_EXTREF_KEY;
+        key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
+
+        ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
+        if (ret < 0)
+                return ERR_PTR(ret);
+        if (ret > 0)
+                return NULL;
+        if (!btrfs_find_name_in_ext_backref(path, ref_objectid, name, name_len, &extref))
+                return NULL;
+        return extref;
+}
+
+int btrfs_get_inode_ref_index(struct btrfs_trans_handle *trans,
+                              struct btrfs_root *root,
+                              struct btrfs_path *path,
+                              const char *name, int name_len,
+                              u64 inode_objectid, u64 ref_objectid, int mod,
+                              u64 *ret_index)
+{
+        struct btrfs_inode_ref *ref;
+        struct btrfs_inode_extref *extref;
+        int ins_len = mod < 0 ? -1 : 0;
+        int cow = mod != 0;
+
+        ref = btrfs_lookup_inode_ref(trans, root, path, name, name_len,
+                                     inode_objectid, ref_objectid, ins_len,
+                                     cow);
+        if (IS_ERR(ref))
+                return PTR_ERR(ref);
+
+        if (ref != NULL) {
+                *ret_index = btrfs_inode_ref_index(path->nodes[0], ref);
+                return 0;
+        }
+
+        btrfs_release_path(path);
+
+        extref = btrfs_lookup_inode_extref(trans, root, path, name,
+                                           name_len, inode_objectid,
+                                           ref_objectid, ins_len, cow);
+        if (IS_ERR(extref))
+                return PTR_ERR(extref);
+
+        if (extref) {
+                *ret_index = btrfs_inode_extref_index(path->nodes[0], extref);
+                return 0;
+        }
+
+        return -ENOENT;
+}
+
+int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root,
                            const char *name, int name_len,
                            u64 inode_objectid, u64 ref_objectid, u64 *index)
 {
         struct btrfs_path *path;
         struct btrfs_key key;
+        struct btrfs_inode_extref *extref;
+        struct extent_buffer *leaf;
+        int ret;
+        int del_len = name_len + sizeof(*extref);
+        unsigned long ptr;
+        unsigned long item_start;
+        u32 item_size;
+
+        key.objectid = inode_objectid;
+        btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
+        key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+
+        path->leave_spinning = 1;
+
+        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+        if (ret > 0)
+                ret = -ENOENT;
+        if (ret < 0)
+                goto out;
+
+        /*
+         * Sanity check - did we find the right item for this name?
+         * This should always succeed so error here will make the FS
+         * readonly.
+         */
+        if (!btrfs_find_name_in_ext_backref(path, ref_objectid,
+                                            name, name_len, &extref)) {
+                btrfs_std_error(root->fs_info, -ENOENT);
+                ret = -EROFS;
+                goto out;
+        }
+
+        leaf = path->nodes[0];
+        item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+        if (index)
+                *index = btrfs_inode_extref_index(leaf, extref);
+
+        if (del_len == item_size) {
+                /*
+                 * Common case only one ref in the item, remove the
+                 * whole item.
+                 */
+                ret = btrfs_del_item(trans, root, path);
+                goto out;
+        }
+
+        ptr = (unsigned long)extref;
+        item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
+
+        memmove_extent_buffer(leaf, ptr, ptr + del_len,
+                              item_size - (ptr + del_len - item_start));
+
+        btrfs_truncate_item(trans, root, path, item_size - del_len, 1);
+
+out:
+        btrfs_free_path(path);
+
+        return ret;
+}
+
+int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
+                        struct btrfs_root *root,
+                        const char *name, int name_len,
+                        u64 inode_objectid, u64 ref_objectid, u64 *index)
+{
+        struct btrfs_path *path;
+        struct btrfs_key key;
         struct btrfs_inode_ref *ref;
         struct extent_buffer *leaf;
         unsigned long ptr;
@@ -91,6 +268,7 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
         u32 item_size;
         u32 sub_item_len;
         int ret;
+        int search_ext_refs = 0;
         int del_len = name_len + sizeof(*ref);
 
         key.objectid = inode_objectid;
@@ -106,12 +284,14 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
         if (ret > 0) {
                 ret = -ENOENT;
+                search_ext_refs = 1;
                 goto out;
         } else if (ret < 0) {
                 goto out;
         }
         if (!find_name_in_backref(path, name, name_len, &ref)) {
                 ret = -ENOENT;
+                search_ext_refs = 1;
                 goto out;
         }
         leaf = path->nodes[0];
@@ -129,8 +309,78 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
         item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
         memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
                               item_size - (ptr + sub_item_len - item_start));
-        btrfs_truncate_item(trans, root, path,
-                                  item_size - sub_item_len, 1);
+        btrfs_truncate_item(trans, root, path, item_size - sub_item_len, 1);
+out:
+        btrfs_free_path(path);
+
+        if (search_ext_refs) {
+                /*
+                 * No refs were found, or we could not find the
+                 * name in our ref array. Find and remove the extended
+                 * inode ref then.
+                 */
+                return btrfs_del_inode_extref(trans, root, name, name_len,
+                                              inode_objectid, ref_objectid, index);
+        }
+
+        return ret;
+}
+
+/*
+ * btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
+ *
+ * The caller must have checked against BTRFS_LINK_MAX already.
+ */
+static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
+                                     struct btrfs_root *root,
+                                     const char *name, int name_len,
+                                     u64 inode_objectid, u64 ref_objectid, u64 index)
+{
+        struct btrfs_inode_extref *extref;
+        int ret;
+        int ins_len = name_len + sizeof(*extref);
+        unsigned long ptr;
+        struct btrfs_path *path;
+        struct btrfs_key key;
+        struct extent_buffer *leaf;
+        struct btrfs_item *item;
+
+        key.objectid = inode_objectid;
+        key.type = BTRFS_INODE_EXTREF_KEY;
+        key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+
+        path->leave_spinning = 1;
+        ret = btrfs_insert_empty_item(trans, root, path, &key,
+                                      ins_len);
+        if (ret == -EEXIST) {
+                if (btrfs_find_name_in_ext_backref(path, ref_objectid,
+                                                   name, name_len, NULL))
+                        goto out;
+
+                btrfs_extend_item(trans, root, path, ins_len);
+                ret = 0;
+        }
+        if (ret < 0)
+                goto out;
+
+        leaf = path->nodes[0];
+        item = btrfs_item_nr(leaf, path->slots[0]);
+        ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
+        ptr += btrfs_item_size(leaf, item) - ins_len;
+        extref = (struct btrfs_inode_extref *)ptr;
+
+        btrfs_set_inode_extref_name_len(path->nodes[0], extref, name_len);
+        btrfs_set_inode_extref_index(path->nodes[0], extref, index);
+        btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
+
+        ptr = (unsigned long)&extref->name;
+        write_extent_buffer(path->nodes[0], name, ptr, name_len);
+        btrfs_mark_buffer_dirty(path->nodes[0]);
+
 out:
         btrfs_free_path(path);
         return ret;
@@ -191,6 +441,19 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 
 out:
         btrfs_free_path(path);
+
+        if (ret == -EMLINK) {
+                struct btrfs_super_block *disk_super = root->fs_info->super_copy;
+                /* We ran out of space in the ref array. Need to
+                 * add an extended ref. */
+                if (btrfs_super_incompat_flags(disk_super)
+                    & BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
+                        ret = btrfs_insert_inode_extref(trans, root, name,
+                                                        name_len,
+                                                        inode_objectid,
+                                                        ref_objectid, index);
+        }
+
         return ret;
 }
 
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 1c50f7c4f5ac..596305e4d75b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2903,7 +2903,6 @@ static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
         struct btrfs_trans_handle *trans;
         struct btrfs_root *root = BTRFS_I(dir)->root;
         struct btrfs_path *path;
-        struct btrfs_inode_ref *ref;
         struct btrfs_dir_item *di;
         struct inode *inode = dentry->d_inode;
         u64 index;
@@ -3017,17 +3016,17 @@ static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
         }
         btrfs_release_path(path);
 
-        ref = btrfs_lookup_inode_ref(trans, root, path,
-                                dentry->d_name.name, dentry->d_name.len,
-                                ino, dir_ino, 0);
-        if (IS_ERR(ref)) {
-                err = PTR_ERR(ref);
+        ret = btrfs_get_inode_ref_index(trans, root, path, dentry->d_name.name,
+                                        dentry->d_name.len, ino, dir_ino, 0,
+                                        &index);
+        if (ret) {
+                err = ret;
                 goto out;
         }
-        BUG_ON(!ref); /* Logic error */
+
         if (check_path_shared(root, path))
                 goto out;
-        index = btrfs_inode_ref_index(path->nodes[0], ref);
+
         btrfs_release_path(path);
 
         /*
@@ -4743,6 +4742,12 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
         key[0].offset = 0;
 
+        /*
+         * Start new inodes with an inode_ref. This is slightly more
+         * efficient for small numbers of hard links since they will
+         * be packed into one item. Extended refs will kick in if we
+         * add more hard links than can fit in the ref item.
+         */
         key[1].objectid = objectid;
         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
         key[1].offset = ref_objectid;
@@ -5049,7 +5054,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
         if (root->objectid != BTRFS_I(inode)->root->objectid)
                 return -EXDEV;
 
-        if (inode->i_nlink == ~0U)
+        if (inode->i_nlink >= BTRFS_LINK_MAX)
                 return -EMLINK;
 
         err = btrfs_set_inode_index(dir, &index);
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 15dae589e59f..1d7b34844323 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -24,8 +24,10 @@
 #include "disk-io.h"
 #include "locking.h"
 #include "print-tree.h"
+#include "backref.h"
 #include "compat.h"
 #include "tree-log.h"
+#include "hash.h"
 
 /* magic values for the inode_only field in btrfs_log_inode:
  *
@@ -743,6 +745,7 @@ out:
  */
 static noinline int backref_in_log(struct btrfs_root *log,
                                    struct btrfs_key *key,
+                                   u64 ref_objectid,
                                    char *name, int namelen)
 {
         struct btrfs_path *path;
@@ -763,8 +766,17 @@ static noinline int backref_in_log(struct btrfs_root *log,
         if (ret != 0)
                 goto out;
 
-        item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
         ptr = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
+
+        if (key->type == BTRFS_INODE_EXTREF_KEY) {
+                if (btrfs_find_name_in_ext_backref(path, ref_objectid,
+                                                   name, namelen, NULL))
+                        match = 1;
+
+                goto out;
+        }
+
+        item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
         ptr_end = ptr + item_size;
         while (ptr < ptr_end) {
                 ref = (struct btrfs_inode_ref *)ptr;
@@ -790,27 +802,36 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
                                   struct btrfs_path *path,
                                   struct btrfs_root *log_root,
                                   struct inode *dir, struct inode *inode,
-                                  struct btrfs_key *key,
                                   struct extent_buffer *eb,
-                                  struct btrfs_inode_ref *ref,
-                                  char *name, int namelen, int *search_done)
+                                  u64 inode_objectid, u64 parent_objectid,
+                                  u64 ref_index, char *name, int namelen,
+                                  int *search_done)
 {
         int ret;
+        char *victim_name;
+        int victim_name_len;
+        struct extent_buffer *leaf;
         struct btrfs_dir_item *di;
+        struct btrfs_key search_key;
+        struct btrfs_inode_extref *extref;
 
-        ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
+again:
+        /* Search old style refs */
+        search_key.objectid = inode_objectid;
+        search_key.type = BTRFS_INODE_REF_KEY;
+        search_key.offset = parent_objectid;
+        ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
         if (ret == 0) {
-                char *victim_name;
-                int victim_name_len;
                 struct btrfs_inode_ref *victim_ref;
                 unsigned long ptr;
                 unsigned long ptr_end;
-                struct extent_buffer *leaf = path->nodes[0];
+
+                leaf = path->nodes[0];
 
                 /* are we trying to overwrite a back ref for the root directory
                  * if so, just jump out, we're done
                  */
-                if (key->objectid == key->offset)
+                if (search_key.objectid == search_key.offset)
                         return 1;
 
                 /* check all the names in this back reference to see
@@ -830,7 +851,9 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
                                            (unsigned long)(victim_ref + 1),
                                            victim_name_len);
 
-                        if (!backref_in_log(log_root, key, victim_name,
+                        if (!backref_in_log(log_root, &search_key,
+                                            parent_objectid,
+                                            victim_name,
                                             victim_name_len)) {
                                 btrfs_inc_nlink(inode);
                                 btrfs_release_path(path);
@@ -838,9 +861,14 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
                                 ret = btrfs_unlink_inode(trans, root, dir,
                                                          inode, victim_name,
                                                          victim_name_len);
+                                BUG_ON(ret);
                                 btrfs_run_delayed_items(trans, root);
+                                kfree(victim_name);
+                                *search_done = 1;
+                                goto again;
                         }
                         kfree(victim_name);
+
                         ptr = (unsigned long)(victim_ref + 1) + victim_name_len;
                 }
                 BUG_ON(ret);
@@ -853,10 +881,74 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
         }
         btrfs_release_path(path);
 
+        /* Same search but for extended refs */
+        extref = btrfs_lookup_inode_extref(NULL, root, path, name, namelen,
+                                           inode_objectid, parent_objectid, 0,
+                                           0);
+        if (!IS_ERR_OR_NULL(extref)) {
+                u32 item_size;
+                u32 cur_offset = 0;
+                unsigned long base;
+                struct inode *victim_parent;
+
+                leaf = path->nodes[0];
+
+                item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+                base = btrfs_item_ptr_offset(leaf, path->slots[0]);
+
+                while (cur_offset < item_size) {
+                        extref = (struct btrfs_inode_extref *)base + cur_offset;
+
+                        victim_name_len = btrfs_inode_extref_name_len(leaf, extref);
+
+                        if (btrfs_inode_extref_parent(leaf, extref) != parent_objectid)
+                                goto next;
+
+                        victim_name = kmalloc(victim_name_len, GFP_NOFS);
+                        read_extent_buffer(leaf, victim_name, (unsigned long)&extref->name,
+                                           victim_name_len);
+
+                        search_key.objectid = inode_objectid;
+                        search_key.type = BTRFS_INODE_EXTREF_KEY;
+                        search_key.offset = btrfs_extref_hash(parent_objectid,
+                                                              victim_name,
+                                                              victim_name_len);
+                        ret = 0;
+                        if (!backref_in_log(log_root, &search_key,
+                                            parent_objectid, victim_name,
+                                            victim_name_len)) {
+                                ret = -ENOENT;
+                                victim_parent = read_one_inode(root,
+                                                               parent_objectid);
+                                if (victim_parent) {
+                                        btrfs_inc_nlink(inode);
+                                        btrfs_release_path(path);
+
+                                        ret = btrfs_unlink_inode(trans, root,
+                                                                 victim_parent,
+                                                                 inode,
+                                                                 victim_name,
+                                                                 victim_name_len);
+                                        btrfs_run_delayed_items(trans, root);
+                                }
+                                BUG_ON(ret);
+                                iput(victim_parent);
+                                kfree(victim_name);
+                                *search_done = 1;
+                                goto again;
+                        }
+                        kfree(victim_name);
+                        BUG_ON(ret);
+next:
+                        cur_offset += victim_name_len + sizeof(*extref);
+                }
+                *search_done = 1;
+        }
+        btrfs_release_path(path);
+
         /* look for a conflicting sequence number */
         di = btrfs_lookup_dir_index_item(trans, root, path, btrfs_ino(dir),
-                                         btrfs_inode_ref_index(eb, ref),
-                                         name, namelen, 0);
+                                         ref_index, name, namelen, 0);
         if (di && !IS_ERR(di)) {
                 ret = drop_one_dir_item(trans, root, path, dir, di);
                 BUG_ON(ret);
@@ -875,6 +967,48 @@ static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
         return 0;
 }
 
+static int extref_get_fields(struct extent_buffer *eb, unsigned long ref_ptr,
+                             u32 *namelen, char **name, u64 *index,
+                             u64 *parent_objectid)
+{
+        struct btrfs_inode_extref *extref;
+
+        extref = (struct btrfs_inode_extref *)ref_ptr;
+
+        *namelen = btrfs_inode_extref_name_len(eb, extref);
+        *name = kmalloc(*namelen, GFP_NOFS);
+        if (*name == NULL)
+                return -ENOMEM;
+
+        read_extent_buffer(eb, *name, (unsigned long)&extref->name,
+                           *namelen);
+
+        *index = btrfs_inode_extref_index(eb, extref);
+        if (parent_objectid)
+                *parent_objectid = btrfs_inode_extref_parent(eb, extref);
+
+        return 0;
+}
+
+static int ref_get_fields(struct extent_buffer *eb, unsigned long ref_ptr,
+                          u32 *namelen, char **name, u64 *index)
+{
+        struct btrfs_inode_ref *ref;
+
+        ref = (struct btrfs_inode_ref *)ref_ptr;
+
+        *namelen = btrfs_inode_ref_name_len(eb, ref);
+        *name = kmalloc(*namelen, GFP_NOFS);
+        if (*name == NULL)
+                return -ENOMEM;
+
+        read_extent_buffer(eb, *name, (unsigned long)(ref + 1), *namelen);
+
+        *index = btrfs_inode_ref_index(eb, ref);
+
+        return 0;
+}
+
 /*
  * replay one inode back reference item found in the log tree.
  * eb, slot and key refer to the buffer and key found in the log tree.
@@ -888,7 +1022,6 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
                                   struct extent_buffer *eb, int slot,
                                   struct btrfs_key *key)
 {
-        struct btrfs_inode_ref *ref;
         struct inode *dir;
         struct inode *inode;
         unsigned long ref_ptr;
@@ -897,6 +1030,27 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
         int namelen;
         int ret;
         int search_done = 0;
+        int log_ref_ver = 0;
+        u64 parent_objectid;
+        u64 inode_objectid;
+        u64 ref_index;
+        int ref_struct_size;
+
+        ref_ptr = btrfs_item_ptr_offset(eb, slot);
+        ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);
+
+        if (key->type == BTRFS_INODE_EXTREF_KEY) {
+                struct btrfs_inode_extref *r;
+
+                ref_struct_size = sizeof(struct btrfs_inode_extref);
+                log_ref_ver = 1;
+                r = (struct btrfs_inode_extref *)ref_ptr;
+                parent_objectid = btrfs_inode_extref_parent(eb, r);
+        } else {
+                ref_struct_size = sizeof(struct btrfs_inode_ref);
+                parent_objectid = key->offset;
+        }
+        inode_objectid = key->objectid;
 
         /*
          * it is possible that we didn't log all the parent directories
@@ -904,32 +1058,38 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
          * copy the back ref in.  The link count fixup code will take
          * care of the rest
          */
-        dir = read_one_inode(root, key->offset);
+        dir = read_one_inode(root, parent_objectid);
         if (!dir)
                 return -ENOENT;
 
-        inode = read_one_inode(root, key->objectid);
+        inode = read_one_inode(root, inode_objectid);
         if (!inode) {
                 iput(dir);
                 return -EIO;
         }
 
-        ref_ptr = btrfs_item_ptr_offset(eb, slot);
-        ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);
-
         while (ref_ptr < ref_end) {
-                ref = (struct btrfs_inode_ref *)ref_ptr;
-
-                namelen = btrfs_inode_ref_name_len(eb, ref);
-                name = kmalloc(namelen, GFP_NOFS);
-                BUG_ON(!name);
-
-                read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);
+                if (log_ref_ver) {
+                        ret = extref_get_fields(eb, ref_ptr, &namelen, &name,
+                                                &ref_index, &parent_objectid);
+                        /*
+                         * parent object can change from one array
+                         * item to another.
+                         */
+                        if (!dir)
+                                dir = read_one_inode(root, parent_objectid);
+                        if (!dir)
+                                return -ENOENT;
+                } else {
+                        ret = ref_get_fields(eb, ref_ptr, &namelen, &name,
+                                             &ref_index);
+                }
+                if (ret)
+                        return ret;
 
                 /* if we already have a perfect match, we're done */
                 if (!inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
-                                  btrfs_inode_ref_index(eb, ref),
-                                  name, namelen)) {
+                                  ref_index, name, namelen)) {
                         /*
                          * look for a conflicting back reference in the
                          * metadata. if we find one we have to unlink that name
@@ -940,8 +1100,10 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 
                         if (!search_done) {
                                 ret = __add_inode_ref(trans, root, path, log,
-                                                      dir, inode, key, eb, ref,
-                                                      name, namelen,
+                                                      dir, inode, eb,
+                                                      inode_objectid,
+                                                      parent_objectid,
+                                                      ref_index, name, namelen,
                                                       &search_done);
                                 if (ret == 1)
                                         goto out;
@@ -950,14 +1112,18 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 
                         /* insert our name */
                         ret = btrfs_add_link(trans, dir, inode, name, namelen,
-                                             0, btrfs_inode_ref_index(eb, ref));
+                                             0, ref_index);
                         BUG_ON(ret);
 
                         btrfs_update_inode(trans, root, inode);
                 }
 
-                ref_ptr = (unsigned long)(ref + 1) + namelen;
+                ref_ptr = (unsigned long)(ref_ptr + ref_struct_size) + namelen;
                 kfree(name);
+                if (log_ref_ver) {
+                        iput(dir);
+                        dir = NULL;
+                }
         }
 
         /* finally write the back reference in the inode */
@@ -981,25 +1147,55 @@ static int insert_orphan_item(struct btrfs_trans_handle *trans,
         return ret;
 }
 
+static int count_inode_extrefs(struct btrfs_root *root,
+                               struct inode *inode, struct btrfs_path *path)
+{
+        int ret = 0;
+        int name_len;
+        unsigned int nlink = 0;
+        u32 item_size;
+        u32 cur_offset = 0;
+        u64 inode_objectid = btrfs_ino(inode);
+        u64 offset = 0;
+        unsigned long ptr;
+        struct btrfs_inode_extref *extref;
+        struct extent_buffer *leaf;
 
-/*
- * There are a few corners where the link count of the file can't
- * be properly maintained during replay.  So, instead of adding
- * lots of complexity to the log code, we just scan the backrefs
- * for any file that has been through replay.
- *
- * The scan will update the link count on the inode to reflect the
- * number of back refs found.  If it goes down to zero, the iput
- * will free the inode.
- */
-static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
-                                           struct btrfs_root *root,
-                                           struct inode *inode)
+        while (1) {
+                ret = btrfs_find_one_extref(root, inode_objectid, offset, path,
+                                            &extref, &offset);
+                if (ret)
+                        break;
+
+                leaf = path->nodes[0];
+                item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+                ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
+
+                while (cur_offset < item_size) {
+                        extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
+                        name_len = btrfs_inode_extref_name_len(leaf, extref);
+
+                        nlink++;
+
+                        cur_offset += name_len + sizeof(*extref);
+                }
+
+                offset++;
+                btrfs_release_path(path);
+        }
+        btrfs_release_path(path);
+
+        if (ret < 0)
+                return ret;
+        return nlink;
+}
+
+static int count_inode_refs(struct btrfs_root *root,
+                               struct inode *inode, struct btrfs_path *path)
 {
-        struct btrfs_path *path;
         int ret;
         struct btrfs_key key;
-        u64 nlink = 0;
+        unsigned int nlink = 0;
         unsigned long ptr;
         unsigned long ptr_end;
         int name_len;
@@ -1009,10 +1205,6 @@ static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
         key.type = BTRFS_INODE_REF_KEY;
         key.offset = (u64)-1;
 
-        path = btrfs_alloc_path();
-        if (!path)
-                return -ENOMEM;
-
         while (1) {
                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
                 if (ret < 0)
@@ -1046,6 +1238,50 @@ static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
                 btrfs_release_path(path);
         }
         btrfs_release_path(path);
+
+        return nlink;
+}
+
+/*
+ * There are a few corners where the link count of the file can't
+ * be properly maintained during replay.  So, instead of adding
+ * lots of complexity to the log code, we just scan the backrefs
+ * for any file that has been through replay.
+ *
+ * The scan will update the link count on the inode to reflect the
+ * number of back refs found.  If it goes down to zero, the iput
+ * will free the inode.
+ */
+static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
+                                           struct btrfs_root *root,
+                                           struct inode *inode)
+{
+        struct btrfs_path *path;
+        int ret;
+        u64 nlink = 0;
+        u64 ino = btrfs_ino(inode);
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+
+        ret = count_inode_refs(root, inode, path);
+        if (ret < 0)
+                goto out;
+
+        nlink = ret;
+
+        ret = count_inode_extrefs(root, inode, path);
+        if (ret == -ENOENT)
+                ret = 0;
+
+        if (ret < 0)
+                goto out;
+
+        nlink += ret;
+
+        ret = 0;
+
         if (nlink != inode->i_nlink) {
                 set_nlink(inode, nlink);
                 btrfs_update_inode(trans, root, inode);
@@ -1061,9 +1297,10 @@ static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
                 ret = insert_orphan_item(trans, root, ino);
                 BUG_ON(ret);
         }
-        btrfs_free_path(path);
 
-        return 0;
+out:
+        btrfs_free_path(path);
+        return ret;
 }
 
 static noinline int fixup_inode_link_counts(struct btrfs_trans_handle *trans,
@@ -1710,6 +1947,10 @@ static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb,
                         ret = add_inode_ref(wc->trans, root, log, path,
                                             eb, i, &key);
                         BUG_ON(ret && ret != -ENOENT);
+                } else if (key.type == BTRFS_INODE_EXTREF_KEY) {
+                        ret = add_inode_ref(wc->trans, root, log, path,
+                                            eb, i, &key);
+                        BUG_ON(ret && ret != -ENOENT);
                 } else if (key.type == BTRFS_EXTENT_DATA_KEY) {
                         ret = replay_one_extent(wc->trans, root, path,
                                                 eb, i, &key);